drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/export.h>
  35 #include <linux/sched/rt.h>
  36 #include <linux/delay.h>
  37 #include <linux/kthread.h>
  38 #include <linux/ioport.h>
  39 #include <linux/acpi.h>
  40 #include <linux/highmem.h>
  41
  42 #define CREATE_TRACE_POINTS
  43 #include <trace/events/spi.h>
  44
  45 static void spidev_release(struct device *dev)
  46 {
  47         struct spi_device       *spi = to_spi_device(dev);
  48
  49         /* spi masters may cleanup for released devices */
  50         if (spi->master->cleanup)
  51                 spi->master->cleanup(spi);
  52
  53         spi_master_put(spi->master);
  54         kfree(spi);
  55 }
  56
  57 static ssize_t
  58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  59 {
  60         const struct spi_device *spi = to_spi_device(dev);
  61         int len;
  62
  63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  64         if (len != -ENODEV)
  65                 return len;
  66
  67         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  68 }
  69 static DEVICE_ATTR_RO(modalias);
  70
  71 #define SPI_STATISTICS_ATTRS(field, file)                               \
  72 static ssize_t spi_master_##field##_show(struct device *dev,            \
  73                                          struct device_attribute *attr, \
  74                                          char *buf)                     \
  75 {                                                                       \
  76         struct spi_master *master = container_of(dev,                   \
  77                                                  struct spi_master, dev); \
  78         return spi_statistics_##field##_show(&master->statistics, buf); \
  79 }                                                                       \
  80 static struct device_attribute dev_attr_spi_master_##field = {          \
  81         .attr = { .name = file, .mode = S_IRUGO },                      \
  82         .show = spi_master_##field##_show,                              \
  83 };                                                                      \
  84 static ssize_t spi_device_##field##_show(struct device *dev,            \
  85                                          struct device_attribute *attr, \
  86                                         char *buf)                      \
  87 {                                                                       \
  88         struct spi_device *spi = to_spi_device(dev);                    \
  89         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  90 }                                                                       \
  91 static struct device_attribute dev_attr_spi_device_##field = {          \
  92         .attr = { .name = file, .mode = S_IRUGO },                      \
  93         .show = spi_device_##field##_show,                              \
  94 }
  95
  96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  98                                             char *buf)                  \
  99 {                                                                       \
 100         unsigned long flags;                                            \
 101         ssize_t len;                                                    \
 102         spin_lock_irqsave(&stat->lock, flags);                          \
 103         len = sprintf(buf, format_string, stat->field);                 \
 104         spin_unlock_irqrestore(&stat->lock, flags);                     \
 105         return len;                                                     \
 106 }                                                                       \
 107 SPI_STATISTICS_ATTRS(name, file)
 108
 109 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 110         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 111                                  field, format_string)
 112
 113 SPI_STATISTICS_SHOW(messages, "%lu");
 114 SPI_STATISTICS_SHOW(transfers, "%lu");
 115 SPI_STATISTICS_SHOW(errors, "%lu");
 116 SPI_STATISTICS_SHOW(timedout, "%lu");
 117
 118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 120 SPI_STATISTICS_SHOW(spi_async, "%lu");
 121
 122 SPI_STATISTICS_SHOW(bytes, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 125
 126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 127         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 128                                  "transfer_bytes_histo_" number,        \
 129                                  transfer_bytes_histo[index],  "%lu")
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 147
 148 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 149
 150 static struct attribute *spi_dev_attrs[] = {
 151         &dev_attr_modalias.attr,
 152         NULL,
 153 };
 154
 155 static const struct attribute_group spi_dev_group = {
 156         .attrs  = spi_dev_attrs,
 157 };
 158
 159 static struct attribute *spi_device_statistics_attrs[] = {
 160         &dev_attr_spi_device_messages.attr,
 161         &dev_attr_spi_device_transfers.attr,
 162         &dev_attr_spi_device_errors.attr,
 163         &dev_attr_spi_device_timedout.attr,
 164         &dev_attr_spi_device_spi_sync.attr,
 165         &dev_attr_spi_device_spi_sync_immediate.attr,
 166         &dev_attr_spi_device_spi_async.attr,
 167         &dev_attr_spi_device_bytes.attr,
 168         &dev_attr_spi_device_bytes_rx.attr,
 169         &dev_attr_spi_device_bytes_tx.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 186         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 187         &dev_attr_spi_device_transfers_split_maxsize.attr,
 188         NULL,
 189 };
 190
 191 static const struct attribute_group spi_device_statistics_group = {
 192         .name  = "statistics",
 193         .attrs  = spi_device_statistics_attrs,
 194 };
 195
 196 static const struct attribute_group *spi_dev_groups[] = {
 197         &spi_dev_group,
 198         &spi_device_statistics_group,
 199         NULL,
 200 };
 201
 202 static struct attribute *spi_master_statistics_attrs[] = {
 203         &dev_attr_spi_master_messages.attr,
 204         &dev_attr_spi_master_transfers.attr,
 205         &dev_attr_spi_master_errors.attr,
 206         &dev_attr_spi_master_timedout.attr,
 207         &dev_attr_spi_master_spi_sync.attr,
 208         &dev_attr_spi_master_spi_sync_immediate.attr,
 209         &dev_attr_spi_master_spi_async.attr,
 210         &dev_attr_spi_master_bytes.attr,
 211         &dev_attr_spi_master_bytes_rx.attr,
 212         &dev_attr_spi_master_bytes_tx.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 226         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 227         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 228         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 229         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 230         &dev_attr_spi_master_transfers_split_maxsize.attr,
 231         NULL,
 232 };
 233
 234 static const struct attribute_group spi_master_statistics_group = {
 235         .name  = "statistics",
 236         .attrs  = spi_master_statistics_attrs,
 237 };
 238
 239 static const struct attribute_group *spi_master_groups[] = {
 240         &spi_master_statistics_group,
 241         NULL,
 242 };
 243
 244 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 245                                        struct spi_transfer *xfer,
 246                                        struct spi_master *master)
 247 {
 248         unsigned long flags;
 249         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 250
 251         if (l2len < 0)
 252                 l2len = 0;
 253
 254         spin_lock_irqsave(&stats->lock, flags);
 255
 256         stats->transfers++;
 257         stats->transfer_bytes_histo[l2len]++;
 258
 259         stats->bytes += xfer->len;
 260         if ((xfer->tx_buf) &&
 261             (xfer->tx_buf != master->dummy_tx))
 262                 stats->bytes_tx += xfer->len;
 263         if ((xfer->rx_buf) &&
 264             (xfer->rx_buf != master->dummy_rx))
 265                 stats->bytes_rx += xfer->len;
 266
 267         spin_unlock_irqrestore(&stats->lock, flags);
 268 }
 269 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 270
 271 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 272  * and the sysfs version makes coldplug work too.
 273  */
 274
 275 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 276                                                 const struct spi_device *sdev)
 277 {
 278         while (id->name[0]) {
 279                 if (!strcmp(sdev->modalias, id->name))
 280                         return id;
 281                 id++;
 282         }
 283         return NULL;
 284 }
 285
 286 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 287 {
 288         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 289
 290         return spi_match_id(sdrv->id_table, sdev);
 291 }
 292 EXPORT_SYMBOL_GPL(spi_get_device_id);
 293
 294 static int spi_match_device(struct device *dev, struct device_driver *drv)
 295 {
 296         const struct spi_device *spi = to_spi_device(dev);
 297         const struct spi_driver *sdrv = to_spi_driver(drv);
 298
 299         /* Attempt an OF style match */
 300         if (of_driver_match_device(dev, drv))
 301                 return 1;
 302
 303         /* Then try ACPI */
 304         if (acpi_driver_match_device(dev, drv))
 305                 return 1;
 306
 307         if (sdrv->id_table)
 308                 return !!spi_match_id(sdrv->id_table, spi);
 309
 310         return strcmp(spi->modalias, drv->name) == 0;
 311 }
 312
 313 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 314 {
 315         const struct spi_device         *spi = to_spi_device(dev);
 316         int rc;
 317
 318         rc = acpi_device_uevent_modalias(dev, env);
 319         if (rc != -ENODEV)
 320                 return rc;
 321
 322         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 323         return 0;
 324 }
 325
 326 struct bus_type spi_bus_type = {
 327         .name           = "spi",
 328         .dev_groups     = spi_dev_groups,
 329         .match          = spi_match_device,
 330         .uevent         = spi_uevent,
 331 };
 332 EXPORT_SYMBOL_GPL(spi_bus_type);
 333
 334
 335 static int spi_drv_probe(struct device *dev)
 336 {
 337         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 338         struct spi_device               *spi = to_spi_device(dev);
 339         int ret;
 340
 341         ret = of_clk_set_defaults(dev->of_node, false);
 342         if (ret)
 343                 return ret;
 344
 345         if (dev->of_node) {
 346                 spi->irq = of_irq_get(dev->of_node, 0);
 347                 if (spi->irq == -EPROBE_DEFER)
 348                         return -EPROBE_DEFER;
 349                 if (spi->irq < 0)
 350                         spi->irq = 0;
 351         }
 352
 353         ret = dev_pm_domain_attach(dev, true);
 354         if (ret != -EPROBE_DEFER) {
 355                 ret = sdrv->probe(spi);
 356                 if (ret)
 357                         dev_pm_domain_detach(dev, true);
 358         }
 359
 360         return ret;
 361 }
 362
 363 static int spi_drv_remove(struct device *dev)
 364 {
 365         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 366         int ret;
 367
 368         ret = sdrv->remove(to_spi_device(dev));
 369         dev_pm_domain_detach(dev, true);
 370
 371         return ret;
 372 }
 373
 374 static void spi_drv_shutdown(struct device *dev)
 375 {
 376         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 377
 378         sdrv->shutdown(to_spi_device(dev));
 379 }
 380
 381 /**
 382  * __spi_register_driver - register a SPI driver
 383  * @owner: owner module of the driver to register
 384  * @sdrv: the driver to register
 385  * Context: can sleep
 386  *
 387  * Return: zero on success, else a negative error code.
 388  */
 389 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 390 {
 391         sdrv->driver.owner = owner;
 392         sdrv->driver.bus = &spi_bus_type;
 393         if (sdrv->probe)
 394                 sdrv->driver.probe = spi_drv_probe;
 395         if (sdrv->remove)
 396                 sdrv->driver.remove = spi_drv_remove;
 397         if (sdrv->shutdown)
 398                 sdrv->driver.shutdown = spi_drv_shutdown;
 399         return driver_register(&sdrv->driver);
 400 }
 401 EXPORT_SYMBOL_GPL(__spi_register_driver);
 402
 403 /*-------------------------------------------------------------------------*/
 404
 405 /* SPI devices should normally not be created by SPI device drivers; that
 406  * would make them board-specific.  Similarly with SPI master drivers.
 407  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 408  * with other readonly (flashable) information about mainboard devices.
 409  */
 410
 411 struct boardinfo {
 412         struct list_head        list;
 413         struct spi_board_info   board_info;
 414 };
 415
 416 static LIST_HEAD(board_list);
 417 static LIST_HEAD(spi_master_list);
 418
 419 /*
 420  * Used to protect add/del opertion for board_info list and
 421  * spi_master list, and their matching process
 422  */
 423 static DEFINE_MUTEX(board_lock);
 424
 425 /**
 426  * spi_alloc_device - Allocate a new SPI device
 427  * @master: Controller to which device is connected
 428  * Context: can sleep
 429  *
 430  * Allows a driver to allocate and initialize a spi_device without
 431  * registering it immediately.  This allows a driver to directly
 432  * fill the spi_device with device parameters before calling
 433  * spi_add_device() on it.
 434  *
 435  * Caller is responsible to call spi_add_device() on the returned
 436  * spi_device structure to add it to the SPI master.  If the caller
 437  * needs to discard the spi_device without adding it, then it should
 438  * call spi_dev_put() on it.
 439  *
 440  * Return: a pointer to the new device, or NULL.
 441  */
 442 struct spi_device *spi_alloc_device(struct spi_master *master)
 443 {
 444         struct spi_device       *spi;
 445
 446         if (!spi_master_get(master))
 447                 return NULL;
 448
 449         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 450         if (!spi) {
 451                 spi_master_put(master);
 452                 return NULL;
 453         }
 454
 455         spi->master = master;
 456         spi->dev.parent = &master->dev;
 457         spi->dev.bus = &spi_bus_type;
 458         spi->dev.release = spidev_release;
 459         spi->cs_gpio = -ENOENT;
 460
 461         spin_lock_init(&spi->statistics.lock);
 462
 463         device_initialize(&spi->dev);
 464         return spi;
 465 }
 466 EXPORT_SYMBOL_GPL(spi_alloc_device);
 467
 468 static void spi_dev_set_name(struct spi_device *spi)
 469 {
 470         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 471
 472         if (adev) {
 473                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 474                 return;
 475         }
 476
 477         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 478                      spi->chip_select);
 479 }
 480
 481 static int spi_dev_check(struct device *dev, void *data)
 482 {
 483         struct spi_device *spi = to_spi_device(dev);
 484         struct spi_device *new_spi = data;
 485
 486         if (spi->master == new_spi->master &&
 487             spi->chip_select == new_spi->chip_select)
 488                 return -EBUSY;
 489         return 0;
 490 }
 491
 492 /**
 493  * spi_add_device - Add spi_device allocated with spi_alloc_device
 494  * @spi: spi_device to register
 495  *
 496  * Companion function to spi_alloc_device.  Devices allocated with
 497  * spi_alloc_device can be added onto the spi bus with this function.
 498  *
 499  * Return: 0 on success; negative errno on failure
 500  */
 501 int spi_add_device(struct spi_device *spi)
 502 {
 503         static DEFINE_MUTEX(spi_add_lock);
 504         struct spi_master *master = spi->master;
 505         struct device *dev = master->dev.parent;
 506         int status;
 507
 508         /* Chipselects are numbered 0..max; validate. */
 509         if (spi->chip_select >= master->num_chipselect) {
 510                 dev_err(dev, "cs%d >= max %d\n",
 511                         spi->chip_select,
 512                         master->num_chipselect);
 513                 return -EINVAL;
 514         }
 515
 516         /* Set the bus ID string */
 517         spi_dev_set_name(spi);
 518
 519         /* We need to make sure there's no other device with this
 520          * chipselect **BEFORE** we call setup(), else we'll trash
 521          * its configuration.  Lock against concurrent add() calls.
 522          */
 523         mutex_lock(&spi_add_lock);
 524
 525         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 526         if (status) {
 527                 dev_err(dev, "chipselect %d already in use\n",
 528                                 spi->chip_select);
 529                 goto done;
 530         }
 531
 532         if (master->cs_gpios)
 533                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 534
 535         /* Drivers may modify this initial i/o setup, but will
 536          * normally rely on the device being setup.  Devices
 537          * using SPI_CS_HIGH can't coexist well otherwise...
 538          */
 539         status = spi_setup(spi);
 540         if (status < 0) {
 541                 dev_err(dev, "can't setup %s, status %d\n",
 542                                 dev_name(&spi->dev), status);
 543                 goto done;
 544         }
 545
 546         /* Device may be bound to an active driver when this returns */
 547         status = device_add(&spi->dev);
 548         if (status < 0)
 549                 dev_err(dev, "can't add %s, status %d\n",
 550                                 dev_name(&spi->dev), status);
 551         else
 552                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 553
 554 done:
 555         mutex_unlock(&spi_add_lock);
 556         return status;
 557 }
 558 EXPORT_SYMBOL_GPL(spi_add_device);
 559
 560 /**
 561  * spi_new_device - instantiate one new SPI device
 562  * @master: Controller to which device is connected
 563  * @chip: Describes the SPI device
 564  * Context: can sleep
 565  *
 566  * On typical mainboards, this is purely internal; and it's not needed
 567  * after board init creates the hard-wired devices.  Some development
 568  * platforms may not be able to use spi_register_board_info though, and
 569  * this is exported so that for example a USB or parport based adapter
 570  * driver could add devices (which it would learn about out-of-band).
 571  *
 572  * Return: the new device, or NULL.
 573  */
 574 struct spi_device *spi_new_device(struct spi_master *master,
 575                                   struct spi_board_info *chip)
 576 {
 577         struct spi_device       *proxy;
 578         int                     status;
 579
 580         /* NOTE:  caller did any chip->bus_num checks necessary.
 581          *
 582          * Also, unless we change the return value convention to use
 583          * error-or-pointer (not NULL-or-pointer), troubleshootability
 584          * suggests syslogged diagnostics are best here (ugh).
 585          */
 586
 587         proxy = spi_alloc_device(master);
 588         if (!proxy)
 589                 return NULL;
 590
 591         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 592
 593         proxy->chip_select = chip->chip_select;
 594         proxy->max_speed_hz = chip->max_speed_hz;
 595         proxy->mode = chip->mode;
 596         proxy->irq = chip->irq;
 597         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 598         proxy->dev.platform_data = (void *) chip->platform_data;
 599         proxy->controller_data = chip->controller_data;
 600         proxy->controller_state = NULL;
 601
 602         status = spi_add_device(proxy);
 603         if (status < 0) {
 604                 spi_dev_put(proxy);
 605                 return NULL;
 606         }
 607
 608         return proxy;
 609 }
 610 EXPORT_SYMBOL_GPL(spi_new_device);
 611
 612 /**
 613  * spi_unregister_device - unregister a single SPI device
 614  * @spi: spi_device to unregister
 615  *
 616  * Start making the passed SPI device vanish. Normally this would be handled
 617  * by spi_unregister_master().
 618  */
 619 void spi_unregister_device(struct spi_device *spi)
 620 {
 621         if (!spi)
 622                 return;
 623
 624         if (spi->dev.of_node) {
 625                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 626                 of_node_put(spi->dev.of_node);
 627         }
 628         if (ACPI_COMPANION(&spi->dev))
 629                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 630         device_unregister(&spi->dev);
 631 }
 632 EXPORT_SYMBOL_GPL(spi_unregister_device);
 633
 634 static void spi_match_master_to_boardinfo(struct spi_master *master,
 635                                 struct spi_board_info *bi)
 636 {
 637         struct spi_device *dev;
 638
 639         if (master->bus_num != bi->bus_num)
 640                 return;
 641
 642         dev = spi_new_device(master, bi);
 643         if (!dev)
 644                 dev_err(master->dev.parent, "can't create new device for %s\n",
 645                         bi->modalias);
 646 }
 647
 648 /**
 649  * spi_register_board_info - register SPI devices for a given board
 650  * @info: array of chip descriptors
 651  * @n: how many descriptors are provided
 652  * Context: can sleep
 653  *
 654  * Board-specific early init code calls this (probably during arch_initcall)
 655  * with segments of the SPI device table.  Any device nodes are created later,
 656  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 657  * this table of devices forever, so that reloading a controller driver will
 658  * not make Linux forget about these hard-wired devices.
 659  *
 660  * Other code can also call this, e.g. a particular add-on board might provide
 661  * SPI devices through its expansion connector, so code initializing that board
 662  * would naturally declare its SPI devices.
 663  *
 664  * The board info passed can safely be __initdata ... but be careful of
 665  * any embedded pointers (platform_data, etc), they're copied as-is.
 666  *
 667  * Return: zero on success, else a negative error code.
 668  */
 669 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 670 {
 671         struct boardinfo *bi;
 672         int i;
 673
 674         if (!n)
 675                 return -EINVAL;
 676
 677         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 678         if (!bi)
 679                 return -ENOMEM;
 680
 681         for (i = 0; i < n; i++, bi++, info++) {
 682                 struct spi_master *master;
 683
 684                 memcpy(&bi->board_info, info, sizeof(*info));
 685                 mutex_lock(&board_lock);
 686                 list_add_tail(&bi->list, &board_list);
 687                 list_for_each_entry(master, &spi_master_list, list)
 688                         spi_match_master_to_boardinfo(master, &bi->board_info);
 689                 mutex_unlock(&board_lock);
 690         }
 691
 692         return 0;
 693 }
 694
 695 /*-------------------------------------------------------------------------*/
 696
 697 static void spi_set_cs(struct spi_device *spi, bool enable)
 698 {
 699         if (spi->mode & SPI_CS_HIGH)
 700                 enable = !enable;
 701
 702         if (gpio_is_valid(spi->cs_gpio))
 703                 gpio_set_value(spi->cs_gpio, !enable);
 704         else if (spi->master->set_cs)
 705                 spi->master->set_cs(spi, !enable);
 706 }
 707
 708 #ifdef CONFIG_HAS_DMA
 709 static int spi_map_buf(struct spi_master *master, struct device *dev,
 710                        struct sg_table *sgt, void *buf, size_t len,
 711                        enum dma_data_direction dir)
 712 {
 713         const bool vmalloced_buf = is_vmalloc_addr(buf);
 714         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 715 #ifdef CONFIG_HIGHMEM
 716         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
 717                                 (unsigned long)buf < (PKMAP_BASE +
 718                                         (LAST_PKMAP * PAGE_SIZE)));
 719 #else
 720         const bool kmap_buf = false;
 721 #endif
 722         int desc_len;
 723         int sgs;
 724         struct page *vm_page;
 725         void *sg_buf;
 726         size_t min;
 727         int i, ret;
 728
 729         if (vmalloced_buf || kmap_buf) {
 730                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 731                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 732         } else if (virt_addr_valid(buf)) {
 733                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
 734                 sgs = DIV_ROUND_UP(len, desc_len);
 735         } else {
 736                 return -EINVAL;
 737         }
 738
 739         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 740         if (ret != 0)
 741                 return ret;
 742
 743         for (i = 0; i < sgs; i++) {
 744
 745                 if (vmalloced_buf || kmap_buf) {
 746                         min = min_t(size_t,
 747                                     len, desc_len - offset_in_page(buf));
 748                         if (vmalloced_buf)
 749                                 vm_page = vmalloc_to_page(buf);
 750                         else
 751                                 vm_page = kmap_to_page(buf);
 752                         if (!vm_page) {
 753                                 sg_free_table(sgt);
 754                                 return -ENOMEM;
 755                         }
 756                         sg_set_page(&sgt->sgl[i], vm_page,
 757                                     min, offset_in_page(buf));
 758                 } else {
 759                         min = min_t(size_t, len, desc_len);
 760                         sg_buf = buf;
 761                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
 762                 }
 763
 764                 buf += min;
 765                 len -= min;
 766         }
 767
 768         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 769         if (!ret)
 770                 ret = -ENOMEM;
 771         if (ret < 0) {
 772                 sg_free_table(sgt);
 773                 return ret;
 774         }
 775
 776         sgt->nents = ret;
 777
 778         return 0;
 779 }
 780
 781 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 782                           struct sg_table *sgt, enum dma_data_direction dir)
 783 {
 784         if (sgt->orig_nents) {
 785                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 786                 sg_free_table(sgt);
 787         }
 788 }
 789
 790 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 791 {
 792         struct device *tx_dev, *rx_dev;
 793         struct spi_transfer *xfer;
 794         int ret;
 795
 796         if (!master->can_dma)
 797                 return 0;
 798
 799         if (master->dma_tx)
 800                 tx_dev = master->dma_tx->device->dev;
 801         else
 802                 tx_dev = master->dev.parent;
 803
 804         if (master->dma_rx)
 805                 rx_dev = master->dma_rx->device->dev;
 806         else
 807                 rx_dev = master->dev.parent;
 808
 809         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 810                 if (!master->can_dma(master, msg->spi, xfer))
 811                         continue;
 812
 813                 if (xfer->tx_buf != NULL) {
 814                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 815                                           (void *)xfer->tx_buf, xfer->len,
 816                                           DMA_TO_DEVICE);
 817                         if (ret != 0)
 818                                 return ret;
 819                 }
 820
 821                 if (xfer->rx_buf != NULL) {
 822                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 823                                           xfer->rx_buf, xfer->len,
 824                                           DMA_FROM_DEVICE);
 825                         if (ret != 0) {
 826                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 827                                               DMA_TO_DEVICE);
 828                                 return ret;
 829                         }
 830                 }
 831         }
 832
 833         master->cur_msg_mapped = true;
 834
 835         return 0;
 836 }
 837
 838 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 839 {
 840         struct spi_transfer *xfer;
 841         struct device *tx_dev, *rx_dev;
 842
 843         if (!master->cur_msg_mapped || !master->can_dma)
 844                 return 0;
 845
 846         if (master->dma_tx)
 847                 tx_dev = master->dma_tx->device->dev;
 848         else
 849                 tx_dev = master->dev.parent;
 850
 851         if (master->dma_rx)
 852                 rx_dev = master->dma_rx->device->dev;
 853         else
 854                 rx_dev = master->dev.parent;
 855
 856         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 857                 if (!master->can_dma(master, msg->spi, xfer))
 858                         continue;
 859
 860                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 861                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 862         }
 863
 864         return 0;
 865 }
 866 #else /* !CONFIG_HAS_DMA */
 867 static inline int spi_map_buf(struct spi_master *master,
 868                               struct device *dev, struct sg_table *sgt,
 869                               void *buf, size_t len,
 870                               enum dma_data_direction dir)
 871 {
 872         return -EINVAL;
 873 }
 874
 875 static inline void spi_unmap_buf(struct spi_master *master,
 876                                  struct device *dev, struct sg_table *sgt,
 877                                  enum dma_data_direction dir)
 878 {
 879 }
 880
 881 static inline int __spi_map_msg(struct spi_master *master,
 882                                 struct spi_message *msg)
 883 {
 884         return 0;
 885 }
 886
 887 static inline int __spi_unmap_msg(struct spi_master *master,
 888                                   struct spi_message *msg)
 889 {
 890         return 0;
 891 }
 892 #endif /* !CONFIG_HAS_DMA */
 893
 894 static inline int spi_unmap_msg(struct spi_master *master,
 895                                 struct spi_message *msg)
 896 {
 897         struct spi_transfer *xfer;
 898
 899         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 900                 /*
 901                  * Restore the original value of tx_buf or rx_buf if they are
 902                  * NULL.
 903                  */
 904                 if (xfer->tx_buf == master->dummy_tx)
 905                         xfer->tx_buf = NULL;
 906                 if (xfer->rx_buf == master->dummy_rx)
 907                         xfer->rx_buf = NULL;
 908         }
 909
 910         return __spi_unmap_msg(master, msg);
 911 }
 912
 913 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 914 {
 915         struct spi_transfer *xfer;
 916         void *tmp;
 917         unsigned int max_tx, max_rx;
 918
 919         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 920                 max_tx = 0;
 921                 max_rx = 0;
 922
 923                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 924                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 925                             !xfer->tx_buf)
 926                                 max_tx = max(xfer->len, max_tx);
 927                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 928                             !xfer->rx_buf)
 929                                 max_rx = max(xfer->len, max_rx);
 930                 }
 931
 932                 if (max_tx) {
 933                         tmp = krealloc(master->dummy_tx, max_tx,
 934                                        GFP_KERNEL | GFP_DMA);
 935                         if (!tmp)
 936                                 return -ENOMEM;
 937                         master->dummy_tx = tmp;
 938                         memset(tmp, 0, max_tx);
 939                 }
 940
 941                 if (max_rx) {
 942                         tmp = krealloc(master->dummy_rx, max_rx,
 943                                        GFP_KERNEL | GFP_DMA);
 944                         if (!tmp)
 945                                 return -ENOMEM;
 946                         master->dummy_rx = tmp;
 947                 }
 948
 949                 if (max_tx || max_rx) {
 950                         list_for_each_entry(xfer, &msg->transfers,
 951                                             transfer_list) {
 952                                 if (!xfer->tx_buf)
 953                                         xfer->tx_buf = master->dummy_tx;
 954                                 if (!xfer->rx_buf)
 955                                         xfer->rx_buf = master->dummy_rx;
 956                         }
 957                 }
 958         }
 959
 960         return __spi_map_msg(master, msg);
 961 }
 962
 963 /*
 964  * spi_transfer_one_message - Default implementation of transfer_one_message()
 965  *
 966  * This is a standard implementation of transfer_one_message() for
 967  * drivers which implement a transfer_one() operation.  It provides
 968  * standard handling of delays and chip select management.
 969  */
 970 static int spi_transfer_one_message(struct spi_master *master,
 971                                     struct spi_message *msg)
 972 {
 973         struct spi_transfer *xfer;
 974         bool keep_cs = false;
 975         int ret = 0;
 976         unsigned long long ms = 1;
 977         struct spi_statistics *statm = &master->statistics;
 978         struct spi_statistics *stats = &msg->spi->statistics;
 979
 980         spi_set_cs(msg->spi, true);
 981
 982         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 983         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 984
 985         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 986                 trace_spi_transfer_start(msg, xfer);
 987
 988                 spi_statistics_add_transfer_stats(statm, xfer, master);
 989                 spi_statistics_add_transfer_stats(stats, xfer, master);
 990
 991                 if (xfer->tx_buf || xfer->rx_buf) {
 992                         reinit_completion(&master->xfer_completion);
 993
 994                         ret = master->transfer_one(master, msg->spi, xfer);
 995                         if (ret < 0) {
 996                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 997                                                                errors);
 998                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 999                                                                errors);
1000                                 dev_err(&msg->spi->dev,
1001                                         "SPI transfer failed: %d\n", ret);
1002                                 goto out;
1003                         }
1004
1005                         if (ret > 0) {
1006                                 ret = 0;
1007                                 ms = 8LL * 1000LL * xfer->len;
1008                                 do_div(ms, xfer->speed_hz);
1009                                 ms += ms + 200; /* some tolerance */
1010
1011                                 if (ms > UINT_MAX)
1012                                         ms = UINT_MAX;
1013
1014                                 ms = wait_for_completion_timeout(&master->xfer_completion,
1015                                                                  msecs_to_jiffies(ms));
1016                         }
1017
1018                         if (ms == 0) {
1019                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1020                                                                timedout);
1021                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1022                                                                timedout);
1023                                 dev_err(&msg->spi->dev,
1024                                         "SPI transfer timed out\n");
1025                                 msg->status = -ETIMEDOUT;
1026                         }
1027                 } else {
1028                         if (xfer->len)
1029                                 dev_err(&msg->spi->dev,
1030                                         "Bufferless transfer has length %u\n",
1031                                         xfer->len);
1032                 }
1033
1034                 trace_spi_transfer_stop(msg, xfer);
1035
1036                 if (msg->status != -EINPROGRESS)
1037                         goto out;
1038
1039                 if (xfer->delay_usecs)
1040                         udelay(xfer->delay_usecs);
1041
1042                 if (xfer->cs_change) {
1043                         if (list_is_last(&xfer->transfer_list,
1044                                          &msg->transfers)) {
1045                                 keep_cs = true;
1046                         } else {
1047                                 spi_set_cs(msg->spi, false);
1048                                 udelay(10);
1049                                 spi_set_cs(msg->spi, true);
1050                         }
1051                 }
1052
1053                 msg->actual_length += xfer->len;
1054         }
1055
1056 out:
1057         if (ret != 0 || !keep_cs)
1058                 spi_set_cs(msg->spi, false);
1059
1060         if (msg->status == -EINPROGRESS)
1061                 msg->status = ret;
1062
1063         if (msg->status && master->handle_err)
1064                 master->handle_err(master, msg);
1065
1066         spi_res_release(master, msg);
1067
1068         spi_finalize_current_message(master);
1069
1070         return ret;
1071 }
1072
1073 /**
1074  * spi_finalize_current_transfer - report completion of a transfer
1075  * @master: the master reporting completion
1076  *
1077  * Called by SPI drivers using the core transfer_one_message()
1078  * implementation to notify it that the current interrupt driven
1079  * transfer has finished and the next one may be scheduled.
1080  */
1081 void spi_finalize_current_transfer(struct spi_master *master)
1082 {
1083         complete(&master->xfer_completion);
1084 }
1085 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1086
1087 /**
1088  * __spi_pump_messages - function which processes spi message queue
1089  * @master: master to process queue for
1090  * @in_kthread: true if we are in the context of the message pump thread
1091  *
1092  * This function checks if there is any spi message in the queue that
1093  * needs processing and if so call out to the driver to initialize hardware
1094  * and transfer each message.
1095  *
1096  * Note that it is called both from the kthread itself and also from
1097  * inside spi_sync(); the queue extraction handling at the top of the
1098  * function should deal with this safely.
1099  */
1100 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1101 {
1102         unsigned long flags;
1103         bool was_busy = false;
1104         int ret;
1105
1106         /* Lock queue */
1107         spin_lock_irqsave(&master->queue_lock, flags);
1108
1109         /* Make sure we are not already running a message */
1110         if (master->cur_msg) {
1111                 spin_unlock_irqrestore(&master->queue_lock, flags);
1112                 return;
1113         }
1114
1115         /* If another context is idling the device then defer */
1116         if (master->idling) {
1117                 kthread_queue_work(&master->kworker, &master->pump_messages);
1118                 spin_unlock_irqrestore(&master->queue_lock, flags);
1119                 return;
1120         }
1121
1122         /* Check if the queue is idle */
1123         if (list_empty(&master->queue) || !master->running) {
1124                 if (!master->busy) {
1125                         spin_unlock_irqrestore(&master->queue_lock, flags);
1126                         return;
1127                 }
1128
1129                 /* Only do teardown in the thread */
1130                 if (!in_kthread) {
1131                         kthread_queue_work(&master->kworker,
1132                                            &master->pump_messages);
1133                         spin_unlock_irqrestore(&master->queue_lock, flags);
1134                         return;
1135                 }
1136
1137                 master->busy = false;
1138                 master->idling = true;
1139                 spin_unlock_irqrestore(&master->queue_lock, flags);
1140
1141                 kfree(master->dummy_rx);
1142                 master->dummy_rx = NULL;
1143                 kfree(master->dummy_tx);
1144                 master->dummy_tx = NULL;
1145                 if (master->unprepare_transfer_hardware &&
1146                     master->unprepare_transfer_hardware(master))
1147                         dev_err(&master->dev,
1148                                 "failed to unprepare transfer hardware\n");
1149                 if (master->auto_runtime_pm) {
1150                         pm_runtime_mark_last_busy(master->dev.parent);
1151                         pm_runtime_put_autosuspend(master->dev.parent);
1152                 }
1153                 trace_spi_master_idle(master);
1154
1155                 spin_lock_irqsave(&master->queue_lock, flags);
1156                 master->idling = false;
1157                 spin_unlock_irqrestore(&master->queue_lock, flags);
1158                 return;
1159         }
1160
1161         /* Extract head of queue */
1162         master->cur_msg =
1163                 list_first_entry(&master->queue, struct spi_message, queue);
1164
1165         list_del_init(&master->cur_msg->queue);
1166         if (master->busy)
1167                 was_busy = true;
1168         else
1169                 master->busy = true;
1170         spin_unlock_irqrestore(&master->queue_lock, flags);
1171
1172         mutex_lock(&master->io_mutex);
1173
1174         if (!was_busy && master->auto_runtime_pm) {
1175                 ret = pm_runtime_get_sync(master->dev.parent);
1176                 if (ret < 0) {
1177                         dev_err(&master->dev, "Failed to power device: %d\n",
1178                                 ret);
1179                         mutex_unlock(&master->io_mutex);
1180                         return;
1181                 }
1182         }
1183
1184         if (!was_busy)
1185                 trace_spi_master_busy(master);
1186
1187         if (!was_busy && master->prepare_transfer_hardware) {
1188                 ret = master->prepare_transfer_hardware(master);
1189                 if (ret) {
1190                         dev_err(&master->dev,
1191                                 "failed to prepare transfer hardware\n");
1192
1193                         if (master->auto_runtime_pm)
1194                                 pm_runtime_put(master->dev.parent);
1195                         mutex_unlock(&master->io_mutex);
1196                         return;
1197                 }
1198         }
1199
1200         trace_spi_message_start(master->cur_msg);
1201
1202         if (master->prepare_message) {
1203                 ret = master->prepare_message(master, master->cur_msg);
1204                 if (ret) {
1205                         dev_err(&master->dev,
1206                                 "failed to prepare message: %d\n", ret);
1207                         master->cur_msg->status = ret;
1208                         spi_finalize_current_message(master);
1209                         goto out;
1210                 }
1211                 master->cur_msg_prepared = true;
1212         }
1213
1214         ret = spi_map_msg(master, master->cur_msg);
1215         if (ret) {
1216                 master->cur_msg->status = ret;
1217                 spi_finalize_current_message(master);
1218                 goto out;
1219         }
1220
1221         ret = master->transfer_one_message(master, master->cur_msg);
1222         if (ret) {
1223                 dev_err(&master->dev,
1224                         "failed to transfer one message from queue\n");
1225                 goto out;
1226         }
1227
1228 out:
1229         mutex_unlock(&master->io_mutex);
1230
1231         /* Prod the scheduler in case transfer_one() was busy waiting */
1232         if (!ret)
1233                 cond_resched();
1234 }
1235
1236 /**
1237  * spi_pump_messages - kthread work function which processes spi message queue
1238  * @work: pointer to kthread work struct contained in the master struct
1239  */
1240 static void spi_pump_messages(struct kthread_work *work)
1241 {
1242         struct spi_master *master =
1243                 container_of(work, struct spi_master, pump_messages);
1244
1245         __spi_pump_messages(master, true);
1246 }
1247
1248 static int spi_init_queue(struct spi_master *master)
1249 {
1250         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1251
1252         master->running = false;
1253         master->busy = false;
1254
1255         kthread_init_worker(&master->kworker);
1256         master->kworker_task = kthread_run(kthread_worker_fn,
1257                                            &master->kworker, "%s",
1258                                            dev_name(&master->dev));
1259         if (IS_ERR(master->kworker_task)) {
1260                 dev_err(&master->dev, "failed to create message pump task\n");
1261                 return PTR_ERR(master->kworker_task);
1262         }
1263         kthread_init_work(&master->pump_messages, spi_pump_messages);
1264
1265         /*
1266          * Master config will indicate if this controller should run the
1267          * message pump with high (realtime) priority to reduce the transfer
1268          * latency on the bus by minimising the delay between a transfer
1269          * request and the scheduling of the message pump thread. Without this
1270          * setting the message pump thread will remain at default priority.
1271          */
1272         if (master->rt) {
1273                 dev_info(&master->dev,
1274                         "will run message pump with realtime priority\n");
1275                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1276         }
1277
1278         return 0;
1279 }
1280
1281 /**
1282  * spi_get_next_queued_message() - called by driver to check for queued
1283  * messages
1284  * @master: the master to check for queued messages
1285  *
1286  * If there are more messages in the queue, the next message is returned from
1287  * this call.
1288  *
1289  * Return: the next message in the queue, else NULL if the queue is empty.
1290  */
1291 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1292 {
1293         struct spi_message *next;
1294         unsigned long flags;
1295
1296         /* get a pointer to the next message, if any */
1297         spin_lock_irqsave(&master->queue_lock, flags);
1298         next = list_first_entry_or_null(&master->queue, struct spi_message,
1299                                         queue);
1300         spin_unlock_irqrestore(&master->queue_lock, flags);
1301
1302         return next;
1303 }
1304 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1305
1306 /**
1307  * spi_finalize_current_message() - the current message is complete
1308  * @master: the master to return the message to
1309  *
1310  * Called by the driver to notify the core that the message in the front of the
1311  * queue is complete and can be removed from the queue.
1312  */
1313 void spi_finalize_current_message(struct spi_master *master)
1314 {
1315         struct spi_message *mesg;
1316         unsigned long flags;
1317         int ret;
1318
1319         spin_lock_irqsave(&master->queue_lock, flags);
1320         mesg = master->cur_msg;
1321         spin_unlock_irqrestore(&master->queue_lock, flags);
1322
1323         spi_unmap_msg(master, mesg);
1324
1325         if (master->cur_msg_prepared && master->unprepare_message) {
1326                 ret = master->unprepare_message(master, mesg);
1327                 if (ret) {
1328                         dev_err(&master->dev,
1329                                 "failed to unprepare message: %d\n", ret);
1330                 }
1331         }
1332
1333         spin_lock_irqsave(&master->queue_lock, flags);
1334         master->cur_msg = NULL;
1335         master->cur_msg_prepared = false;
1336         kthread_queue_work(&master->kworker, &master->pump_messages);
1337         spin_unlock_irqrestore(&master->queue_lock, flags);
1338
1339         trace_spi_message_done(mesg);
1340
1341         mesg->state = NULL;
1342         if (mesg->complete)
1343                 mesg->complete(mesg->context);
1344 }
1345 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1346
1347 static int spi_start_queue(struct spi_master *master)
1348 {
1349         unsigned long flags;
1350
1351         spin_lock_irqsave(&master->queue_lock, flags);
1352
1353         if (master->running || master->busy) {
1354                 spin_unlock_irqrestore(&master->queue_lock, flags);
1355                 return -EBUSY;
1356         }
1357
1358         master->running = true;
1359         master->cur_msg = NULL;
1360         spin_unlock_irqrestore(&master->queue_lock, flags);
1361
1362         kthread_queue_work(&master->kworker, &master->pump_messages);
1363
1364         return 0;
1365 }
1366
1367 static int spi_stop_queue(struct spi_master *master)
1368 {
1369         unsigned long flags;
1370         unsigned limit = 500;
1371         int ret = 0;
1372
1373         spin_lock_irqsave(&master->queue_lock, flags);
1374
1375         /*
1376          * This is a bit lame, but is optimized for the common execution path.
1377          * A wait_queue on the master->busy could be used, but then the common
1378          * execution path (pump_messages) would be required to call wake_up or
1379          * friends on every SPI message. Do this instead.
1380          */
1381         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1382                 spin_unlock_irqrestore(&master->queue_lock, flags);
1383                 usleep_range(10000, 11000);
1384                 spin_lock_irqsave(&master->queue_lock, flags);
1385         }
1386
1387         if (!list_empty(&master->queue) || master->busy)
1388                 ret = -EBUSY;
1389         else
1390                 master->running = false;
1391
1392         spin_unlock_irqrestore(&master->queue_lock, flags);
1393
1394         if (ret) {
1395                 dev_warn(&master->dev,
1396                          "could not stop message queue\n");
1397                 return ret;
1398         }
1399         return ret;
1400 }
1401
1402 static int spi_destroy_queue(struct spi_master *master)
1403 {
1404         int ret;
1405
1406         ret = spi_stop_queue(master);
1407
1408         /*
1409          * kthread_flush_worker will block until all work is done.
1410          * If the reason that stop_queue timed out is that the work will never
1411          * finish, then it does no good to call flush/stop thread, so
1412          * return anyway.
1413          */
1414         if (ret) {
1415                 dev_err(&master->dev, "problem destroying queue\n");
1416                 return ret;
1417         }
1418
1419         kthread_flush_worker(&master->kworker);
1420         kthread_stop(master->kworker_task);
1421
1422         return 0;
1423 }
1424
1425 static int __spi_queued_transfer(struct spi_device *spi,
1426                                  struct spi_message *msg,
1427                                  bool need_pump)
1428 {
1429         struct spi_master *master = spi->master;
1430         unsigned long flags;
1431
1432         spin_lock_irqsave(&master->queue_lock, flags);
1433
1434         if (!master->running) {
1435                 spin_unlock_irqrestore(&master->queue_lock, flags);
1436                 return -ESHUTDOWN;
1437         }
1438         msg->actual_length = 0;
1439         msg->status = -EINPROGRESS;
1440
1441         list_add_tail(&msg->queue, &master->queue);
1442         if (!master->busy && need_pump)
1443                 kthread_queue_work(&master->kworker, &master->pump_messages);
1444
1445         spin_unlock_irqrestore(&master->queue_lock, flags);
1446         return 0;
1447 }
1448
1449 /**
1450  * spi_queued_transfer - transfer function for queued transfers
1451  * @spi: spi device which is requesting transfer
1452  * @msg: spi message which is to handled is queued to driver queue
1453  *
1454  * Return: zero on success, else a negative error code.
1455  */
1456 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1457 {
1458         return __spi_queued_transfer(spi, msg, true);
1459 }
1460
1461 static int spi_master_initialize_queue(struct spi_master *master)
1462 {
1463         int ret;
1464
1465         master->transfer = spi_queued_transfer;
1466         if (!master->transfer_one_message)
1467                 master->transfer_one_message = spi_transfer_one_message;
1468
1469         /* Initialize and start queue */
1470         ret = spi_init_queue(master);
1471         if (ret) {
1472                 dev_err(&master->dev, "problem initializing queue\n");
1473                 goto err_init_queue;
1474         }
1475         master->queued = true;
1476         ret = spi_start_queue(master);
1477         if (ret) {
1478                 dev_err(&master->dev, "problem starting queue\n");
1479                 goto err_start_queue;
1480         }
1481
1482         return 0;
1483
1484 err_start_queue:
1485         spi_destroy_queue(master);
1486 err_init_queue:
1487         return ret;
1488 }
1489
1490 /*-------------------------------------------------------------------------*/
1491
1492 #if defined(CONFIG_OF)
1493 static struct spi_device *
1494 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1495 {
1496         struct spi_device *spi;
1497         int rc;
1498         u32 value;
1499
1500         /* Alloc an spi_device */
1501         spi = spi_alloc_device(master);
1502         if (!spi) {
1503                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1504                         nc->full_name);
1505                 rc = -ENOMEM;
1506                 goto err_out;
1507         }
1508
1509         /* Select device driver */
1510         rc = of_modalias_node(nc, spi->modalias,
1511                                 sizeof(spi->modalias));
1512         if (rc < 0) {
1513                 dev_err(&master->dev, "cannot find modalias for %s\n",
1514                         nc->full_name);
1515                 goto err_out;
1516         }
1517
1518         /* Device address */
1519         rc = of_property_read_u32(nc, "reg", &value);
1520         if (rc) {
1521                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1522                         nc->full_name, rc);
1523                 goto err_out;
1524         }
1525         spi->chip_select = value;
1526
1527         /* Mode (clock phase/polarity/etc.) */
1528         if (of_find_property(nc, "spi-cpha", NULL))
1529                 spi->mode |= SPI_CPHA;
1530         if (of_find_property(nc, "spi-cpol", NULL))
1531                 spi->mode |= SPI_CPOL;
1532         if (of_find_property(nc, "spi-cs-high", NULL))
1533                 spi->mode |= SPI_CS_HIGH;
1534         if (of_find_property(nc, "spi-3wire", NULL))
1535                 spi->mode |= SPI_3WIRE;
1536         if (of_find_property(nc, "spi-lsb-first", NULL))
1537                 spi->mode |= SPI_LSB_FIRST;
1538
1539         /* Device DUAL/QUAD mode */
1540         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1541                 switch (value) {
1542                 case 1:
1543                         break;
1544                 case 2:
1545                         spi->mode |= SPI_TX_DUAL;
1546                         break;
1547                 case 4:
1548                         spi->mode |= SPI_TX_QUAD;
1549                         break;
1550                 default:
1551                         dev_warn(&master->dev,
1552                                 "spi-tx-bus-width %d not supported\n",
1553                                 value);
1554                         break;
1555                 }
1556         }
1557
1558         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1559                 switch (value) {
1560                 case 1:
1561                         break;
1562                 case 2:
1563                         spi->mode |= SPI_RX_DUAL;
1564                         break;
1565                 case 4:
1566                         spi->mode |= SPI_RX_QUAD;
1567                         break;
1568                 default:
1569                         dev_warn(&master->dev,
1570                                 "spi-rx-bus-width %d not supported\n",
1571                                 value);
1572                         break;
1573                 }
1574         }
1575
1576         /* Device speed */
1577         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1578         if (rc) {
1579                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1580                         nc->full_name, rc);
1581                 goto err_out;
1582         }
1583         spi->max_speed_hz = value;
1584
1585         /* Store a pointer to the node in the device structure */
1586         of_node_get(nc);
1587         spi->dev.of_node = nc;
1588
1589         /* Register the new device */
1590         rc = spi_add_device(spi);
1591         if (rc) {
1592                 dev_err(&master->dev, "spi_device register error %s\n",
1593                         nc->full_name);
1594                 goto err_of_node_put;
1595         }
1596
1597         return spi;
1598
1599 err_of_node_put:
1600         of_node_put(nc);
1601 err_out:
1602         spi_dev_put(spi);
1603         return ERR_PTR(rc);
1604 }
1605
1606 /**
1607  * of_register_spi_devices() - Register child devices onto the SPI bus
1608  * @master:     Pointer to spi_master device
1609  *
1610  * Registers an spi_device for each child node of master node which has a 'reg'
1611  * property.
1612  */
1613 static void of_register_spi_devices(struct spi_master *master)
1614 {
1615         struct spi_device *spi;
1616         struct device_node *nc;
1617
1618         if (!master->dev.of_node)
1619                 return;
1620
1621         for_each_available_child_of_node(master->dev.of_node, nc) {
1622                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1623                         continue;
1624                 spi = of_register_spi_device(master, nc);
1625                 if (IS_ERR(spi)) {
1626                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1627                                 nc->full_name);
1628                         of_node_clear_flag(nc, OF_POPULATED);
1629                 }
1630         }
1631 }
1632 #else
1633 static void of_register_spi_devices(struct spi_master *master) { }
1634 #endif
1635
1636 #ifdef CONFIG_ACPI
1637 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1638 {
1639         struct spi_device *spi = data;
1640         struct spi_master *master = spi->master;
1641
1642         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1643                 struct acpi_resource_spi_serialbus *sb;
1644
1645                 sb = &ares->data.spi_serial_bus;
1646                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1647                         /*
1648                          * ACPI DeviceSelection numbering is handled by the
1649                          * host controller driver in Windows and can vary
1650                          * from driver to driver. In Linux we always expect
1651                          * 0 .. max - 1 so we need to ask the driver to
1652                          * translate between the two schemes.
1653                          */
1654                         if (master->fw_translate_cs) {
1655                                 int cs = master->fw_translate_cs(master,
1656                                                 sb->device_selection);
1657                                 if (cs < 0)
1658                                         return cs;
1659                                 spi->chip_select = cs;
1660                         } else {
1661                                 spi->chip_select = sb->device_selection;
1662                         }
1663
1664                         spi->max_speed_hz = sb->connection_speed;
1665
1666                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1667                                 spi->mode |= SPI_CPHA;
1668                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1669                                 spi->mode |= SPI_CPOL;
1670                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1671                                 spi->mode |= SPI_CS_HIGH;
1672                 }
1673         } else if (spi->irq < 0) {
1674                 struct resource r;
1675
1676                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1677                         spi->irq = r.start;
1678         }
1679
1680         /* Always tell the ACPI core to skip this resource */
1681         return 1;
1682 }
1683
1684 static acpi_status acpi_register_spi_device(struct spi_master *master,
1685                                             struct acpi_device *adev)
1686 {
1687         struct list_head resource_list;
1688         struct spi_device *spi;
1689         int ret;
1690
1691         if (acpi_bus_get_status(adev) || !adev->status.present ||
1692             acpi_device_enumerated(adev))
1693                 return AE_OK;
1694
1695         spi = spi_alloc_device(master);
1696         if (!spi) {
1697                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1698                         dev_name(&adev->dev));
1699                 return AE_NO_MEMORY;
1700         }
1701
1702         ACPI_COMPANION_SET(&spi->dev, adev);
1703         spi->irq = -1;
1704
1705         INIT_LIST_HEAD(&resource_list);
1706         ret = acpi_dev_get_resources(adev, &resource_list,
1707                                      acpi_spi_add_resource, spi);
1708         acpi_dev_free_resource_list(&resource_list);
1709
1710         if (ret < 0 || !spi->max_speed_hz) {
1711                 spi_dev_put(spi);
1712                 return AE_OK;
1713         }
1714
1715         if (spi->irq < 0)
1716                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1717
1718         acpi_device_set_enumerated(adev);
1719
1720         adev->power.flags.ignore_parent = true;
1721         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1722         if (spi_add_device(spi)) {
1723                 adev->power.flags.ignore_parent = false;
1724                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1725                         dev_name(&adev->dev));
1726                 spi_dev_put(spi);
1727         }
1728
1729         return AE_OK;
1730 }
1731
1732 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1733                                        void *data, void **return_value)
1734 {
1735         struct spi_master *master = data;
1736         struct acpi_device *adev;
1737
1738         if (acpi_bus_get_device(handle, &adev))
1739                 return AE_OK;
1740
1741         return acpi_register_spi_device(master, adev);
1742 }
1743
1744 static void acpi_register_spi_devices(struct spi_master *master)
1745 {
1746         acpi_status status;
1747         acpi_handle handle;
1748
1749         handle = ACPI_HANDLE(master->dev.parent);
1750         if (!handle)
1751                 return;
1752
1753         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1754                                      acpi_spi_add_device, NULL,
1755                                      master, NULL);
1756         if (ACPI_FAILURE(status))
1757                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1758 }
1759 #else
1760 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1761 #endif /* CONFIG_ACPI */
1762
1763 static void spi_master_release(struct device *dev)
1764 {
1765         struct spi_master *master;
1766
1767         master = container_of(dev, struct spi_master, dev);
1768         kfree(master);
1769 }
1770
1771 static struct class spi_master_class = {
1772         .name           = "spi_master",
1773         .owner          = THIS_MODULE,
1774         .dev_release    = spi_master_release,
1775         .dev_groups     = spi_master_groups,
1776 };
1777
1778
1779 /**
1780  * spi_alloc_master - allocate SPI master controller
1781  * @dev: the controller, possibly using the platform_bus
1782  * @size: how much zeroed driver-private data to allocate; the pointer to this
1783  *      memory is in the driver_data field of the returned device,
1784  *      accessible with spi_master_get_devdata().
1785  * Context: can sleep
1786  *
1787  * This call is used only by SPI master controller drivers, which are the
1788  * only ones directly touching chip registers.  It's how they allocate
1789  * an spi_master structure, prior to calling spi_register_master().
1790  *
1791  * This must be called from context that can sleep.
1792  *
1793  * The caller is responsible for assigning the bus number and initializing
1794  * the master's methods before calling spi_register_master(); and (after errors
1795  * adding the device) calling spi_master_put() to prevent a memory leak.
1796  *
1797  * Return: the SPI master structure on success, else NULL.
1798  */
1799 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1800 {
1801         struct spi_master       *master;
1802
1803         if (!dev)
1804                 return NULL;
1805
1806         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1807         if (!master)
1808                 return NULL;
1809
1810         device_initialize(&master->dev);
1811         master->bus_num = -1;
1812         master->num_chipselect = 1;
1813         master->dev.class = &spi_master_class;
1814         master->dev.parent = dev;
1815         pm_suspend_ignore_children(&master->dev, true);
1816         spi_master_set_devdata(master, &master[1]);
1817
1818         return master;
1819 }
1820 EXPORT_SYMBOL_GPL(spi_alloc_master);
1821
1822 #ifdef CONFIG_OF
1823 static int of_spi_register_master(struct spi_master *master)
1824 {
1825         int nb, i, *cs;
1826         struct device_node *np = master->dev.of_node;
1827
1828         if (!np)
1829                 return 0;
1830
1831         nb = of_gpio_named_count(np, "cs-gpios");
1832         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1833
1834         /* Return error only for an incorrectly formed cs-gpios property */
1835         if (nb == 0 || nb == -ENOENT)
1836                 return 0;
1837         else if (nb < 0)
1838                 return nb;
1839
1840         cs = devm_kzalloc(&master->dev,
1841                           sizeof(int) * master->num_chipselect,
1842                           GFP_KERNEL);
1843         master->cs_gpios = cs;
1844
1845         if (!master->cs_gpios)
1846                 return -ENOMEM;
1847
1848         for (i = 0; i < master->num_chipselect; i++)
1849                 cs[i] = -ENOENT;
1850
1851         for (i = 0; i < nb; i++)
1852                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1853
1854         return 0;
1855 }
1856 #else
1857 static int of_spi_register_master(struct spi_master *master)
1858 {
1859         return 0;
1860 }
1861 #endif
1862
1863 /**
1864  * spi_register_master - register SPI master controller
1865  * @master: initialized master, originally from spi_alloc_master()
1866  * Context: can sleep
1867  *
1868  * SPI master controllers connect to their drivers using some non-SPI bus,
1869  * such as the platform bus.  The final stage of probe() in that code
1870  * includes calling spi_register_master() to hook up to this SPI bus glue.
1871  *
1872  * SPI controllers use board specific (often SOC specific) bus numbers,
1873  * and board-specific addressing for SPI devices combines those numbers
1874  * with chip select numbers.  Since SPI does not directly support dynamic
1875  * device identification, boards need configuration tables telling which
1876  * chip is at which address.
1877  *
1878  * This must be called from context that can sleep.  It returns zero on
1879  * success, else a negative error code (dropping the master's refcount).
1880  * After a successful return, the caller is responsible for calling
1881  * spi_unregister_master().
1882  *
1883  * Return: zero on success, else a negative error code.
1884  */
1885 int spi_register_master(struct spi_master *master)
1886 {
1887         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1888         struct device           *dev = master->dev.parent;
1889         struct boardinfo        *bi;
1890         int                     status = -ENODEV;
1891         int                     dynamic = 0;
1892
1893         if (!dev)
1894                 return -ENODEV;
1895
1896         status = of_spi_register_master(master);
1897         if (status)
1898                 return status;
1899
1900         /* even if it's just one always-selected device, there must
1901          * be at least one chipselect
1902          */
1903         if (master->num_chipselect == 0)
1904                 return -EINVAL;
1905
1906         if ((master->bus_num < 0) && master->dev.of_node)
1907                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1908
1909         /* convention:  dynamically assigned bus IDs count down from the max */
1910         if (master->bus_num < 0) {
1911                 /* FIXME switch to an IDR based scheme, something like
1912                  * I2C now uses, so we can't run out of "dynamic" IDs
1913                  */
1914                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1915                 dynamic = 1;
1916         }
1917
1918         INIT_LIST_HEAD(&master->queue);
1919         spin_lock_init(&master->queue_lock);
1920         spin_lock_init(&master->bus_lock_spinlock);
1921         mutex_init(&master->bus_lock_mutex);
1922         mutex_init(&master->io_mutex);
1923         master->bus_lock_flag = 0;
1924         init_completion(&master->xfer_completion);
1925         if (!master->max_dma_len)
1926                 master->max_dma_len = INT_MAX;
1927
1928         /* register the device, then userspace will see it.
1929          * registration fails if the bus ID is in use.
1930          */
1931         dev_set_name(&master->dev, "spi%u", master->bus_num);
1932         status = device_add(&master->dev);
1933         if (status < 0)
1934                 goto done;
1935         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1936                         dynamic ? " (dynamic)" : "");
1937
1938         /* If we're using a queued driver, start the queue */
1939         if (master->transfer)
1940                 dev_info(dev, "master is unqueued, this is deprecated\n");
1941         else {
1942                 status = spi_master_initialize_queue(master);
1943                 if (status) {
1944                         device_del(&master->dev);
1945                         goto done;
1946                 }
1947         }
1948         /* add statistics */
1949         spin_lock_init(&master->statistics.lock);
1950
1951         mutex_lock(&board_lock);
1952         list_add_tail(&master->list, &spi_master_list);
1953         list_for_each_entry(bi, &board_list, list)
1954                 spi_match_master_to_boardinfo(master, &bi->board_info);
1955         mutex_unlock(&board_lock);
1956
1957         /* Register devices from the device tree and ACPI */
1958         of_register_spi_devices(master);
1959         acpi_register_spi_devices(master);
1960 done:
1961         return status;
1962 }
1963 EXPORT_SYMBOL_GPL(spi_register_master);
1964
1965 static void devm_spi_unregister(struct device *dev, void *res)
1966 {
1967         spi_unregister_master(*(struct spi_master **)res);
1968 }
1969
1970 /**
1971  * dev_spi_register_master - register managed SPI master controller
1972  * @dev:    device managing SPI master
1973  * @master: initialized master, originally from spi_alloc_master()
1974  * Context: can sleep
1975  *
1976  * Register a SPI device as with spi_register_master() which will
1977  * automatically be unregister
1978  *
1979  * Return: zero on success, else a negative error code.
1980  */
1981 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1982 {
1983         struct spi_master **ptr;
1984         int ret;
1985
1986         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1987         if (!ptr)
1988                 return -ENOMEM;
1989
1990         ret = spi_register_master(master);
1991         if (!ret) {
1992                 *ptr = master;
1993                 devres_add(dev, ptr);
1994         } else {
1995                 devres_free(ptr);
1996         }
1997
1998         return ret;
1999 }
2000 EXPORT_SYMBOL_GPL(devm_spi_register_master);
2001
2002 static int __unregister(struct device *dev, void *null)
2003 {
2004         spi_unregister_device(to_spi_device(dev));
2005         return 0;
2006 }
2007
2008 /**
2009  * spi_unregister_master - unregister SPI master controller
2010  * @master: the master being unregistered
2011  * Context: can sleep
2012  *
2013  * This call is used only by SPI master controller drivers, which are the
2014  * only ones directly touching chip registers.
2015  *
2016  * This must be called from context that can sleep.
2017  */
2018 void spi_unregister_master(struct spi_master *master)
2019 {
2020         int dummy;
2021
2022         if (master->queued) {
2023                 if (spi_destroy_queue(master))
2024                         dev_err(&master->dev, "queue remove failed\n");
2025         }
2026
2027         mutex_lock(&board_lock);
2028         list_del(&master->list);
2029         mutex_unlock(&board_lock);
2030
2031         dummy = device_for_each_child(&master->dev, NULL, __unregister);
2032         device_unregister(&master->dev);
2033 }
2034 EXPORT_SYMBOL_GPL(spi_unregister_master);
2035
2036 int spi_master_suspend(struct spi_master *master)
2037 {
2038         int ret;
2039
2040         /* Basically no-ops for non-queued masters */
2041         if (!master->queued)
2042                 return 0;
2043
2044         ret = spi_stop_queue(master);
2045         if (ret)
2046                 dev_err(&master->dev, "queue stop failed\n");
2047
2048         return ret;
2049 }
2050 EXPORT_SYMBOL_GPL(spi_master_suspend);
2051
2052 int spi_master_resume(struct spi_master *master)
2053 {
2054         int ret;
2055
2056         if (!master->queued)
2057                 return 0;
2058
2059         ret = spi_start_queue(master);
2060         if (ret)
2061                 dev_err(&master->dev, "queue restart failed\n");
2062
2063         return ret;
2064 }
2065 EXPORT_SYMBOL_GPL(spi_master_resume);
2066
2067 static int __spi_master_match(struct device *dev, const void *data)
2068 {
2069         struct spi_master *m;
2070         const u16 *bus_num = data;
2071
2072         m = container_of(dev, struct spi_master, dev);
2073         return m->bus_num == *bus_num;
2074 }
2075
2076 /**
2077  * spi_busnum_to_master - look up master associated with bus_num
2078  * @bus_num: the master's bus number
2079  * Context: can sleep
2080  *
2081  * This call may be used with devices that are registered after
2082  * arch init time.  It returns a refcounted pointer to the relevant
2083  * spi_master (which the caller must release), or NULL if there is
2084  * no such master registered.
2085  *
2086  * Return: the SPI master structure on success, else NULL.
2087  */
2088 struct spi_master *spi_busnum_to_master(u16 bus_num)
2089 {
2090         struct device           *dev;
2091         struct spi_master       *master = NULL;
2092
2093         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2094                                 __spi_master_match);
2095         if (dev)
2096                 master = container_of(dev, struct spi_master, dev);
2097         /* reference got in class_find_device */
2098         return master;
2099 }
2100 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2101
2102 /*-------------------------------------------------------------------------*/
2103
2104 /* Core methods for SPI resource management */
2105
2106 /**
2107  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2108  *                 during the processing of a spi_message while using
2109  *                 spi_transfer_one
2110  * @spi:     the spi device for which we allocate memory
2111  * @release: the release code to execute for this resource
2112  * @size:    size to alloc and return
2113  * @gfp:     GFP allocation flags
2114  *
2115  * Return: the pointer to the allocated data
2116  *
2117  * This may get enhanced in the future to allocate from a memory pool
2118  * of the @spi_device or @spi_master to avoid repeated allocations.
2119  */
2120 void *spi_res_alloc(struct spi_device *spi,
2121                     spi_res_release_t release,
2122                     size_t size, gfp_t gfp)
2123 {
2124         struct spi_res *sres;
2125
2126         sres = kzalloc(sizeof(*sres) + size, gfp);
2127         if (!sres)
2128                 return NULL;
2129
2130         INIT_LIST_HEAD(&sres->entry);
2131         sres->release = release;
2132
2133         return sres->data;
2134 }
2135 EXPORT_SYMBOL_GPL(spi_res_alloc);
2136
2137 /**
2138  * spi_res_free - free an spi resource
2139  * @res: pointer to the custom data of a resource
2140  *
2141  */
2142 void spi_res_free(void *res)
2143 {
2144         struct spi_res *sres = container_of(res, struct spi_res, data);
2145
2146         if (!res)
2147                 return;
2148
2149         WARN_ON(!list_empty(&sres->entry));
2150         kfree(sres);
2151 }
2152 EXPORT_SYMBOL_GPL(spi_res_free);
2153
2154 /**
2155  * spi_res_add - add a spi_res to the spi_message
2156  * @message: the spi message
2157  * @res:     the spi_resource
2158  */
2159 void spi_res_add(struct spi_message *message, void *res)
2160 {
2161         struct spi_res *sres = container_of(res, struct spi_res, data);
2162
2163         WARN_ON(!list_empty(&sres->entry));
2164         list_add_tail(&sres->entry, &message->resources);
2165 }
2166 EXPORT_SYMBOL_GPL(spi_res_add);
2167
2168 /**
2169  * spi_res_release - release all spi resources for this message
2170  * @master:  the @spi_master
2171  * @message: the @spi_message
2172  */
2173 void spi_res_release(struct spi_master *master,
2174                      struct spi_message *message)
2175 {
2176         struct spi_res *res;
2177
2178         while (!list_empty(&message->resources)) {
2179                 res = list_last_entry(&message->resources,
2180                                       struct spi_res, entry);
2181
2182                 if (res->release)
2183                         res->release(master, message, res->data);
2184
2185                 list_del(&res->entry);
2186
2187                 kfree(res);
2188         }
2189 }
2190 EXPORT_SYMBOL_GPL(spi_res_release);
2191
2192 /*-------------------------------------------------------------------------*/
2193
2194 /* Core methods for spi_message alterations */
2195
2196 static void __spi_replace_transfers_release(struct spi_master *master,
2197                                             struct spi_message *msg,
2198                                             void *res)
2199 {
2200         struct spi_replaced_transfers *rxfer = res;
2201         size_t i;
2202
2203         /* call extra callback if requested */
2204         if (rxfer->release)
2205                 rxfer->release(master, msg, res);
2206
2207         /* insert replaced transfers back into the message */
2208         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2209
2210         /* remove the formerly inserted entries */
2211         for (i = 0; i < rxfer->inserted; i++)
2212                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2213 }
2214
2215 /**
2216  * spi_replace_transfers - replace transfers with several transfers
2217  *                         and register change with spi_message.resources
2218  * @msg:           the spi_message we work upon
2219  * @xfer_first:    the first spi_transfer we want to replace
2220  * @remove:        number of transfers to remove
2221  * @insert:        the number of transfers we want to insert instead
2222  * @release:       extra release code necessary in some circumstances
2223  * @extradatasize: extra data to allocate (with alignment guarantees
2224  *                 of struct @spi_transfer)
2225  * @gfp:           gfp flags
2226  *
2227  * Returns: pointer to @spi_replaced_transfers,
2228  *          PTR_ERR(...) in case of errors.
2229  */
2230 struct spi_replaced_transfers *spi_replace_transfers(
2231         struct spi_message *msg,
2232         struct spi_transfer *xfer_first,
2233         size_t remove,
2234         size_t insert,
2235         spi_replaced_release_t release,
2236         size_t extradatasize,
2237         gfp_t gfp)
2238 {
2239         struct spi_replaced_transfers *rxfer;
2240         struct spi_transfer *xfer;
2241         size_t i;
2242
2243         /* allocate the structure using spi_res */
2244         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2245                               insert * sizeof(struct spi_transfer)
2246                               + sizeof(struct spi_replaced_transfers)
2247                               + extradatasize,
2248                               gfp);
2249         if (!rxfer)
2250                 return ERR_PTR(-ENOMEM);
2251
2252         /* the release code to invoke before running the generic release */
2253         rxfer->release = release;
2254
2255         /* assign extradata */
2256         if (extradatasize)
2257                 rxfer->extradata =
2258                         &rxfer->inserted_transfers[insert];
2259
2260         /* init the replaced_transfers list */
2261         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2262
2263         /* assign the list_entry after which we should reinsert
2264          * the @replaced_transfers - it may be spi_message.messages!
2265          */
2266         rxfer->replaced_after = xfer_first->transfer_list.prev;
2267
2268         /* remove the requested number of transfers */
2269         for (i = 0; i < remove; i++) {
2270                 /* if the entry after replaced_after it is msg->transfers
2271                  * then we have been requested to remove more transfers
2272                  * than are in the list
2273                  */
2274                 if (rxfer->replaced_after->next == &msg->transfers) {
2275                         dev_err(&msg->spi->dev,
2276                                 "requested to remove more spi_transfers than are available\n");
2277                         /* insert replaced transfers back into the message */
2278                         list_splice(&rxfer->replaced_transfers,
2279                                     rxfer->replaced_after);
2280
2281                         /* free the spi_replace_transfer structure */
2282                         spi_res_free(rxfer);
2283
2284                         /* and return with an error */
2285                         return ERR_PTR(-EINVAL);
2286                 }
2287
2288                 /* remove the entry after replaced_after from list of
2289                  * transfers and add it to list of replaced_transfers
2290                  */
2291                 list_move_tail(rxfer->replaced_after->next,
2292                                &rxfer->replaced_transfers);
2293         }
2294
2295         /* create copy of the given xfer with identical settings
2296          * based on the first transfer to get removed
2297          */
2298         for (i = 0; i < insert; i++) {
2299                 /* we need to run in reverse order */
2300                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2301
2302                 /* copy all spi_transfer data */
2303                 memcpy(xfer, xfer_first, sizeof(*xfer));
2304
2305                 /* add to list */
2306                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2307
2308                 /* clear cs_change and delay_usecs for all but the last */
2309                 if (i) {
2310                         xfer->cs_change = false;
2311                         xfer->delay_usecs = 0;
2312                 }
2313         }
2314
2315         /* set up inserted */
2316         rxfer->inserted = insert;
2317
2318         /* and register it with spi_res/spi_message */
2319         spi_res_add(msg, rxfer);
2320
2321         return rxfer;
2322 }
2323 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2324
2325 static int __spi_split_transfer_maxsize(struct spi_master *master,
2326                                         struct spi_message *msg,
2327                                         struct spi_transfer **xferp,
2328                                         size_t maxsize,
2329                                         gfp_t gfp)
2330 {
2331         struct spi_transfer *xfer = *xferp, *xfers;
2332         struct spi_replaced_transfers *srt;
2333         size_t offset;
2334         size_t count, i;
2335
2336         /* warn once about this fact that we are splitting a transfer */
2337         dev_warn_once(&msg->spi->dev,
2338                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2339                       xfer->len, maxsize);
2340
2341         /* calculate how many we have to replace */
2342         count = DIV_ROUND_UP(xfer->len, maxsize);
2343
2344         /* create replacement */
2345         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2346         if (IS_ERR(srt))
2347                 return PTR_ERR(srt);
2348         xfers = srt->inserted_transfers;
2349
2350         /* now handle each of those newly inserted spi_transfers
2351          * note that the replacements spi_transfers all are preset
2352          * to the same values as *xferp, so tx_buf, rx_buf and len
2353          * are all identical (as well as most others)
2354          * so we just have to fix up len and the pointers.
2355          *
2356          * this also includes support for the depreciated
2357          * spi_message.is_dma_mapped interface
2358          */
2359
2360         /* the first transfer just needs the length modified, so we
2361          * run it outside the loop
2362          */
2363         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2364
2365         /* all the others need rx_buf/tx_buf also set */
2366         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2367                 /* update rx_buf, tx_buf and dma */
2368                 if (xfers[i].rx_buf)
2369                         xfers[i].rx_buf += offset;
2370                 if (xfers[i].rx_dma)
2371                         xfers[i].rx_dma += offset;
2372                 if (xfers[i].tx_buf)
2373                         xfers[i].tx_buf += offset;
2374                 if (xfers[i].tx_dma)
2375                         xfers[i].tx_dma += offset;
2376
2377                 /* update length */
2378                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2379         }
2380
2381         /* we set up xferp to the last entry we have inserted,
2382          * so that we skip those already split transfers
2383          */
2384         *xferp = &xfers[count - 1];
2385
2386         /* increment statistics counters */
2387         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2388                                        transfers_split_maxsize);
2389         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2390                                        transfers_split_maxsize);
2391
2392         return 0;
2393 }
2394
2395 /**
2396  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2397  *                              when an individual transfer exceeds a
2398  *                              certain size
2399  * @master:    the @spi_master for this transfer
2400  * @msg:   the @spi_message to transform
2401  * @maxsize:  the maximum when to apply this
2402  * @gfp: GFP allocation flags
2403  *
2404  * Return: status of transformation
2405  */
2406 int spi_split_transfers_maxsize(struct spi_master *master,
2407                                 struct spi_message *msg,
2408                                 size_t maxsize,
2409                                 gfp_t gfp)
2410 {
2411         struct spi_transfer *xfer;
2412         int ret;
2413
2414         /* iterate over the transfer_list,
2415          * but note that xfer is advanced to the last transfer inserted
2416          * to avoid checking sizes again unnecessarily (also xfer does
2417          * potentiall belong to a different list by the time the
2418          * replacement has happened
2419          */
2420         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2421                 if (xfer->len > maxsize) {
2422                         ret = __spi_split_transfer_maxsize(
2423                                 master, msg, &xfer, maxsize, gfp);
2424                         if (ret)
2425                                 return ret;
2426                 }
2427         }
2428
2429         return 0;
2430 }
2431 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2432
2433 /*-------------------------------------------------------------------------*/
2434
2435 /* Core methods for SPI master protocol drivers.  Some of the
2436  * other core methods are currently defined as inline functions.
2437  */
2438
2439 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2440 {
2441         if (master->bits_per_word_mask) {
2442                 /* Only 32 bits fit in the mask */
2443                 if (bits_per_word > 32)
2444                         return -EINVAL;
2445                 if (!(master->bits_per_word_mask &
2446                                 SPI_BPW_MASK(bits_per_word)))
2447                         return -EINVAL;
2448         }
2449
2450         return 0;
2451 }
2452
2453 /**
2454  * spi_setup - setup SPI mode and clock rate
2455  * @spi: the device whose settings are being modified
2456  * Context: can sleep, and no requests are queued to the device
2457  *
2458  * SPI protocol drivers may need to update the transfer mode if the
2459  * device doesn't work with its default.  They may likewise need
2460  * to update clock rates or word sizes from initial values.  This function
2461  * changes those settings, and must be called from a context that can sleep.
2462  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2463  * effect the next time the device is selected and data is transferred to
2464  * or from it.  When this function returns, the spi device is deselected.
2465  *
2466  * Note that this call will fail if the protocol driver specifies an option
2467  * that the underlying controller or its driver does not support.  For
2468  * example, not all hardware supports wire transfers using nine bit words,
2469  * LSB-first wire encoding, or active-high chipselects.
2470  *
2471  * Return: zero on success, else a negative error code.
2472  */
2473 int spi_setup(struct spi_device *spi)
2474 {
2475         unsigned        bad_bits, ugly_bits;
2476         int             status;
2477
2478         /* check mode to prevent that DUAL and QUAD set at the same time
2479          */
2480         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2481                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2482                 dev_err(&spi->dev,
2483                 "setup: can not select dual and quad at the same time\n");
2484                 return -EINVAL;
2485         }
2486         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2487          */
2488         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2489                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2490                 return -EINVAL;
2491         /* help drivers fail *cleanly* when they need options
2492          * that aren't supported with their current master
2493          */
2494         bad_bits = spi->mode & ~spi->master->mode_bits;
2495         ugly_bits = bad_bits &
2496                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2497         if (ugly_bits) {
2498                 dev_warn(&spi->dev,
2499                          "setup: ignoring unsupported mode bits %x\n",
2500                          ugly_bits);
2501                 spi->mode &= ~ugly_bits;
2502                 bad_bits &= ~ugly_bits;
2503         }
2504         if (bad_bits) {
2505                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2506                         bad_bits);
2507                 return -EINVAL;
2508         }
2509
2510         if (!spi->bits_per_word)
2511                 spi->bits_per_word = 8;
2512
2513         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2514         if (status)
2515                 return status;
2516
2517         if (!spi->max_speed_hz)
2518                 spi->max_speed_hz = spi->master->max_speed_hz;
2519
2520         if (spi->master->setup)
2521                 status = spi->master->setup(spi);
2522
2523         spi_set_cs(spi, false);
2524
2525         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2526                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2527                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2528                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2529                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2530                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2531                         spi->bits_per_word, spi->max_speed_hz,
2532                         status);
2533
2534         return status;
2535 }
2536 EXPORT_SYMBOL_GPL(spi_setup);
2537
2538 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2539 {
2540         struct spi_master *master = spi->master;
2541         struct spi_transfer *xfer;
2542         int w_size;
2543
2544         if (list_empty(&message->transfers))
2545                 return -EINVAL;
2546
2547         /* Half-duplex links include original MicroWire, and ones with
2548          * only one data pin like SPI_3WIRE (switches direction) or where
2549          * either MOSI or MISO is missing.  They can also be caused by
2550          * software limitations.
2551          */
2552         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2553                         || (spi->mode & SPI_3WIRE)) {
2554                 unsigned flags = master->flags;
2555
2556                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2557                         if (xfer->rx_buf && xfer->tx_buf)
2558                                 return -EINVAL;
2559                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2560                                 return -EINVAL;
2561                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2562                                 return -EINVAL;
2563                 }
2564         }
2565
2566         /**
2567          * Set transfer bits_per_word and max speed as spi device default if
2568          * it is not set for this transfer.
2569          * Set transfer tx_nbits and rx_nbits as single transfer default
2570          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2571          */
2572         message->frame_length = 0;
2573         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2574                 message->frame_length += xfer->len;
2575                 if (!xfer->bits_per_word)
2576                         xfer->bits_per_word = spi->bits_per_word;
2577
2578                 if (!xfer->speed_hz)
2579                         xfer->speed_hz = spi->max_speed_hz;
2580                 if (!xfer->speed_hz)
2581                         xfer->speed_hz = master->max_speed_hz;
2582
2583                 if (master->max_speed_hz &&
2584                     xfer->speed_hz > master->max_speed_hz)
2585                         xfer->speed_hz = master->max_speed_hz;
2586
2587                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2588                         return -EINVAL;
2589
2590                 /*
2591                  * SPI transfer length should be multiple of SPI word size
2592                  * where SPI word size should be power-of-two multiple
2593                  */
2594                 if (xfer->bits_per_word <= 8)
2595                         w_size = 1;
2596                 else if (xfer->bits_per_word <= 16)
2597                         w_size = 2;
2598                 else
2599                         w_size = 4;
2600
2601                 /* No partial transfers accepted */
2602                 if (xfer->len % w_size)
2603                         return -EINVAL;
2604
2605                 if (xfer->speed_hz && master->min_speed_hz &&
2606                     xfer->speed_hz < master->min_speed_hz)
2607                         return -EINVAL;
2608
2609                 if (xfer->tx_buf && !xfer->tx_nbits)
2610                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2611                 if (xfer->rx_buf && !xfer->rx_nbits)
2612                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2613                 /* check transfer tx/rx_nbits:
2614                  * 1. check the value matches one of single, dual and quad
2615                  * 2. check tx/rx_nbits match the mode in spi_device
2616                  */
2617                 if (xfer->tx_buf) {
2618                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2619                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2620                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2621                                 return -EINVAL;
2622                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2623                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2624                                 return -EINVAL;
2625                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2626                                 !(spi->mode & SPI_TX_QUAD))
2627                                 return -EINVAL;
2628                 }
2629                 /* check transfer rx_nbits */
2630                 if (xfer->rx_buf) {
2631                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2632                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2633                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2634                                 return -EINVAL;
2635                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2636                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2637                                 return -EINVAL;
2638                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2639                                 !(spi->mode & SPI_RX_QUAD))
2640                                 return -EINVAL;
2641                 }
2642         }
2643
2644         message->status = -EINPROGRESS;
2645
2646         return 0;
2647 }
2648
2649 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2650 {
2651         struct spi_master *master = spi->master;
2652
2653         message->spi = spi;
2654
2655         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2656         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2657
2658         trace_spi_message_submit(message);
2659
2660         return master->transfer(spi, message);
2661 }
2662
2663 /**
2664  * spi_async - asynchronous SPI transfer
2665  * @spi: device with which data will be exchanged
2666  * @message: describes the data transfers, including completion callback
2667  * Context: any (irqs may be blocked, etc)
2668  *
2669  * This call may be used in_irq and other contexts which can't sleep,
2670  * as well as from task contexts which can sleep.
2671  *
2672  * The completion callback is invoked in a context which can't sleep.
2673  * Before that invocation, the value of message->status is undefined.
2674  * When the callback is issued, message->status holds either zero (to
2675  * indicate complete success) or a negative error code.  After that
2676  * callback returns, the driver which issued the transfer request may
2677  * deallocate the associated memory; it's no longer in use by any SPI
2678  * core or controller driver code.
2679  *
2680  * Note that although all messages to a spi_device are handled in
2681  * FIFO order, messages may go to different devices in other orders.
2682  * Some device might be higher priority, or have various "hard" access
2683  * time requirements, for example.
2684  *
2685  * On detection of any fault during the transfer, processing of
2686  * the entire message is aborted, and the device is deselected.
2687  * Until returning from the associated message completion callback,
2688  * no other spi_message queued to that device will be processed.
2689  * (This rule applies equally to all the synchronous transfer calls,
2690  * which are wrappers around this core asynchronous primitive.)
2691  *
2692  * Return: zero on success, else a negative error code.
2693  */
2694 int spi_async(struct spi_device *spi, struct spi_message *message)
2695 {
2696         struct spi_master *master = spi->master;
2697         int ret;
2698         unsigned long flags;
2699
2700         ret = __spi_validate(spi, message);
2701         if (ret != 0)
2702                 return ret;
2703
2704         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2705
2706         if (master->bus_lock_flag)
2707                 ret = -EBUSY;
2708         else
2709                 ret = __spi_async(spi, message);
2710
2711         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2712
2713         return ret;
2714 }
2715 EXPORT_SYMBOL_GPL(spi_async);
2716
2717 /**
2718  * spi_async_locked - version of spi_async with exclusive bus usage
2719  * @spi: device with which data will be exchanged
2720  * @message: describes the data transfers, including completion callback
2721  * Context: any (irqs may be blocked, etc)
2722  *
2723  * This call may be used in_irq and other contexts which can't sleep,
2724  * as well as from task contexts which can sleep.
2725  *
2726  * The completion callback is invoked in a context which can't sleep.
2727  * Before that invocation, the value of message->status is undefined.
2728  * When the callback is issued, message->status holds either zero (to
2729  * indicate complete success) or a negative error code.  After that
2730  * callback returns, the driver which issued the transfer request may
2731  * deallocate the associated memory; it's no longer in use by any SPI
2732  * core or controller driver code.
2733  *
2734  * Note that although all messages to a spi_device are handled in
2735  * FIFO order, messages may go to different devices in other orders.
2736  * Some device might be higher priority, or have various "hard" access
2737  * time requirements, for example.
2738  *
2739  * On detection of any fault during the transfer, processing of
2740  * the entire message is aborted, and the device is deselected.
2741  * Until returning from the associated message completion callback,
2742  * no other spi_message queued to that device will be processed.
2743  * (This rule applies equally to all the synchronous transfer calls,
2744  * which are wrappers around this core asynchronous primitive.)
2745  *
2746  * Return: zero on success, else a negative error code.
2747  */
2748 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2749 {
2750         struct spi_master *master = spi->master;
2751         int ret;
2752         unsigned long flags;
2753
2754         ret = __spi_validate(spi, message);
2755         if (ret != 0)
2756                 return ret;
2757
2758         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2759
2760         ret = __spi_async(spi, message);
2761
2762         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2763
2764         return ret;
2765
2766 }
2767 EXPORT_SYMBOL_GPL(spi_async_locked);
2768
2769
2770 int spi_flash_read(struct spi_device *spi,
2771                    struct spi_flash_read_message *msg)
2772
2773 {
2774         struct spi_master *master = spi->master;
2775         struct device *rx_dev = NULL;
2776         int ret;
2777
2778         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2779              msg->addr_nbits == SPI_NBITS_DUAL) &&
2780             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2781                 return -EINVAL;
2782         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2783              msg->addr_nbits == SPI_NBITS_QUAD) &&
2784             !(spi->mode & SPI_TX_QUAD))
2785                 return -EINVAL;
2786         if (msg->data_nbits == SPI_NBITS_DUAL &&
2787             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2788                 return -EINVAL;
2789         if (msg->data_nbits == SPI_NBITS_QUAD &&
2790             !(spi->mode &  SPI_RX_QUAD))
2791                 return -EINVAL;
2792
2793         if (master->auto_runtime_pm) {
2794                 ret = pm_runtime_get_sync(master->dev.parent);
2795                 if (ret < 0) {
2796                         dev_err(&master->dev, "Failed to power device: %d\n",
2797                                 ret);
2798                         return ret;
2799                 }
2800         }
2801
2802         mutex_lock(&master->bus_lock_mutex);
2803         mutex_lock(&master->io_mutex);
2804         if (master->dma_rx) {
2805                 rx_dev = master->dma_rx->device->dev;
2806                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2807                                   msg->buf, msg->len,
2808                                   DMA_FROM_DEVICE);
2809                 if (!ret)
2810                         msg->cur_msg_mapped = true;
2811         }
2812         ret = master->spi_flash_read(spi, msg);
2813         if (msg->cur_msg_mapped)
2814                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2815                               DMA_FROM_DEVICE);
2816         mutex_unlock(&master->io_mutex);
2817         mutex_unlock(&master->bus_lock_mutex);
2818
2819         if (master->auto_runtime_pm)
2820                 pm_runtime_put(master->dev.parent);
2821
2822         return ret;
2823 }
2824 EXPORT_SYMBOL_GPL(spi_flash_read);
2825
2826 /*-------------------------------------------------------------------------*/
2827
2828 /* Utility methods for SPI master protocol drivers, layered on
2829  * top of the core.  Some other utility methods are defined as
2830  * inline functions.
2831  */
2832
2833 static void spi_complete(void *arg)
2834 {
2835         complete(arg);
2836 }
2837
2838 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2839 {
2840         DECLARE_COMPLETION_ONSTACK(done);
2841         int status;
2842         struct spi_master *master = spi->master;
2843         unsigned long flags;
2844
2845         status = __spi_validate(spi, message);
2846         if (status != 0)
2847                 return status;
2848
2849         message->complete = spi_complete;
2850         message->context = &done;
2851         message->spi = spi;
2852
2853         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2854         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2855
2856         /* If we're not using the legacy transfer method then we will
2857          * try to transfer in the calling context so special case.
2858          * This code would be less tricky if we could remove the
2859          * support for driver implemented message queues.
2860          */
2861         if (master->transfer == spi_queued_transfer) {
2862                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2863
2864                 trace_spi_message_submit(message);
2865
2866                 status = __spi_queued_transfer(spi, message, false);
2867
2868                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2869         } else {
2870                 status = spi_async_locked(spi, message);
2871         }
2872
2873         if (status == 0) {
2874                 /* Push out the messages in the calling context if we
2875                  * can.
2876                  */
2877                 if (master->transfer == spi_queued_transfer) {
2878                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2879                                                        spi_sync_immediate);
2880                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2881                                                        spi_sync_immediate);
2882                         __spi_pump_messages(master, false);
2883                 }
2884
2885                 wait_for_completion(&done);
2886                 status = message->status;
2887         }
2888         message->context = NULL;
2889         return status;
2890 }
2891
2892 /**
2893  * spi_sync - blocking/synchronous SPI data transfers
2894  * @spi: device with which data will be exchanged
2895  * @message: describes the data transfers
2896  * Context: can sleep
2897  *
2898  * This call may only be used from a context that may sleep.  The sleep
2899  * is non-interruptible, and has no timeout.  Low-overhead controller
2900  * drivers may DMA directly into and out of the message buffers.
2901  *
2902  * Note that the SPI device's chip select is active during the message,
2903  * and then is normally disabled between messages.  Drivers for some
2904  * frequently-used devices may want to minimize costs of selecting a chip,
2905  * by leaving it selected in anticipation that the next message will go
2906  * to the same chip.  (That may increase power usage.)
2907  *
2908  * Also, the caller is guaranteeing that the memory associated with the
2909  * message will not be freed before this call returns.
2910  *
2911  * Return: zero on success, else a negative error code.
2912  */
2913 int spi_sync(struct spi_device *spi, struct spi_message *message)
2914 {
2915         int ret;
2916
2917         mutex_lock(&spi->master->bus_lock_mutex);
2918         ret = __spi_sync(spi, message);
2919         mutex_unlock(&spi->master->bus_lock_mutex);
2920
2921         return ret;
2922 }
2923 EXPORT_SYMBOL_GPL(spi_sync);
2924
2925 /**
2926  * spi_sync_locked - version of spi_sync with exclusive bus usage
2927  * @spi: device with which data will be exchanged
2928  * @message: describes the data transfers
2929  * Context: can sleep
2930  *
2931  * This call may only be used from a context that may sleep.  The sleep
2932  * is non-interruptible, and has no timeout.  Low-overhead controller
2933  * drivers may DMA directly into and out of the message buffers.
2934  *
2935  * This call should be used by drivers that require exclusive access to the
2936  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2937  * be released by a spi_bus_unlock call when the exclusive access is over.
2938  *
2939  * Return: zero on success, else a negative error code.
2940  */
2941 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2942 {
2943         return __spi_sync(spi, message);
2944 }
2945 EXPORT_SYMBOL_GPL(spi_sync_locked);
2946
2947 /**
2948  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2949  * @master: SPI bus master that should be locked for exclusive bus access
2950  * Context: can sleep
2951  *
2952  * This call may only be used from a context that may sleep.  The sleep
2953  * is non-interruptible, and has no timeout.
2954  *
2955  * This call should be used by drivers that require exclusive access to the
2956  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2957  * exclusive access is over. Data transfer must be done by spi_sync_locked
2958  * and spi_async_locked calls when the SPI bus lock is held.
2959  *
2960  * Return: always zero.
2961  */
2962 int spi_bus_lock(struct spi_master *master)
2963 {
2964         unsigned long flags;
2965
2966         mutex_lock(&master->bus_lock_mutex);
2967
2968         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2969         master->bus_lock_flag = 1;
2970         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2971
2972         /* mutex remains locked until spi_bus_unlock is called */
2973
2974         return 0;
2975 }
2976 EXPORT_SYMBOL_GPL(spi_bus_lock);
2977
2978 /**
2979  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2980  * @master: SPI bus master that was locked for exclusive bus access
2981  * Context: can sleep
2982  *
2983  * This call may only be used from a context that may sleep.  The sleep
2984  * is non-interruptible, and has no timeout.
2985  *
2986  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2987  * call.
2988  *
2989  * Return: always zero.
2990  */
2991 int spi_bus_unlock(struct spi_master *master)
2992 {
2993         master->bus_lock_flag = 0;
2994
2995         mutex_unlock(&master->bus_lock_mutex);
2996
2997         return 0;
2998 }
2999 EXPORT_SYMBOL_GPL(spi_bus_unlock);
3000
3001 /* portable code must never pass more than 32 bytes */
3002 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
3003
3004 static u8       *buf;
3005
3006 /**
3007  * spi_write_then_read - SPI synchronous write followed by read
3008  * @spi: device with which data will be exchanged
3009  * @txbuf: data to be written (need not be dma-safe)
3010  * @n_tx: size of txbuf, in bytes
3011  * @rxbuf: buffer into which data will be read (need not be dma-safe)
3012  * @n_rx: size of rxbuf, in bytes
3013  * Context: can sleep
3014  *
3015  * This performs a half duplex MicroWire style transaction with the
3016  * device, sending txbuf and then reading rxbuf.  The return value
3017  * is zero for success, else a negative errno status code.
3018  * This call may only be used from a context that may sleep.
3019  *
3020  * Parameters to this routine are always copied using a small buffer;
3021  * portable code should never use this for more than 32 bytes.
3022  * Performance-sensitive or bulk transfer code should instead use
3023  * spi_{async,sync}() calls with dma-safe buffers.
3024  *
3025  * Return: zero on success, else a negative error code.
3026  */
3027 int spi_write_then_read(struct spi_device *spi,
3028                 const void *txbuf, unsigned n_tx,
3029                 void *rxbuf, unsigned n_rx)
3030 {
3031         static DEFINE_MUTEX(lock);
3032
3033         int                     status;
3034         struct spi_message      message;
3035         struct spi_transfer     x[2];
3036         u8                      *local_buf;
3037
3038         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3039          * copying here, (as a pure convenience thing), but we can
3040          * keep heap costs out of the hot path unless someone else is
3041          * using the pre-allocated buffer or the transfer is too large.
3042          */
3043         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3044                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3045                                     GFP_KERNEL | GFP_DMA);
3046                 if (!local_buf)
3047                         return -ENOMEM;
3048         } else {
3049                 local_buf = buf;
3050         }
3051
3052         spi_message_init(&message);
3053         memset(x, 0, sizeof(x));
3054         if (n_tx) {
3055                 x[0].len = n_tx;
3056                 spi_message_add_tail(&x[0], &message);
3057         }
3058         if (n_rx) {
3059                 x[1].len = n_rx;
3060                 spi_message_add_tail(&x[1], &message);
3061         }
3062
3063         memcpy(local_buf, txbuf, n_tx);
3064         x[0].tx_buf = local_buf;
3065         x[1].rx_buf = local_buf + n_tx;
3066
3067         /* do the i/o */
3068         status = spi_sync(spi, &message);
3069         if (status == 0)
3070                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3071
3072         if (x[0].tx_buf == buf)
3073                 mutex_unlock(&lock);
3074         else
3075                 kfree(local_buf);
3076
3077         return status;
3078 }
3079 EXPORT_SYMBOL_GPL(spi_write_then_read);
3080
3081 /*-------------------------------------------------------------------------*/
3082
3083 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3084 static int __spi_of_device_match(struct device *dev, void *data)
3085 {
3086         return dev->of_node == data;
3087 }
3088
3089 /* must call put_device() when done with returned spi_device device */
3090 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3091 {
3092         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3093                                                 __spi_of_device_match);
3094         return dev ? to_spi_device(dev) : NULL;
3095 }
3096
3097 static int __spi_of_master_match(struct device *dev, const void *data)
3098 {
3099         return dev->of_node == data;
3100 }
3101
3102 /* the spi masters are not using spi_bus, so we find it with another way */
3103 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3104 {
3105         struct device *dev;
3106
3107         dev = class_find_device(&spi_master_class, NULL, node,
3108                                 __spi_of_master_match);
3109         if (!dev)
3110                 return NULL;
3111
3112         /* reference got in class_find_device */
3113         return container_of(dev, struct spi_master, dev);
3114 }
3115
3116 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3117                          void *arg)
3118 {
3119         struct of_reconfig_data *rd = arg;
3120         struct spi_master *master;
3121         struct spi_device *spi;
3122
3123         switch (of_reconfig_get_state_change(action, arg)) {
3124         case OF_RECONFIG_CHANGE_ADD:
3125                 master = of_find_spi_master_by_node(rd->dn->parent);
3126                 if (master == NULL)
3127                         return NOTIFY_OK;       /* not for us */
3128
3129                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3130                         put_device(&master->dev);
3131                         return NOTIFY_OK;
3132                 }
3133
3134                 spi = of_register_spi_device(master, rd->dn);
3135                 put_device(&master->dev);
3136
3137                 if (IS_ERR(spi)) {
3138                         pr_err("%s: failed to create for '%s'\n",
3139                                         __func__, rd->dn->full_name);
3140                         of_node_clear_flag(rd->dn, OF_POPULATED);
3141                         return notifier_from_errno(PTR_ERR(spi));
3142                 }
3143                 break;
3144
3145         case OF_RECONFIG_CHANGE_REMOVE:
3146                 /* already depopulated? */
3147                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3148                         return NOTIFY_OK;
3149
3150                 /* find our device by node */
3151                 spi = of_find_spi_device_by_node(rd->dn);
3152                 if (spi == NULL)
3153                         return NOTIFY_OK;       /* no? not meant for us */
3154
3155                 /* unregister takes one ref away */
3156                 spi_unregister_device(spi);
3157
3158                 /* and put the reference of the find */
3159                 put_device(&spi->dev);
3160                 break;
3161         }
3162
3163         return NOTIFY_OK;
3164 }
3165
3166 static struct notifier_block spi_of_notifier = {
3167         .notifier_call = of_spi_notify,
3168 };
3169 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3170 extern struct notifier_block spi_of_notifier;
3171 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3172
3173 #if IS_ENABLED(CONFIG_ACPI)
3174 static int spi_acpi_master_match(struct device *dev, const void *data)
3175 {
3176         return ACPI_COMPANION(dev->parent) == data;
3177 }
3178
3179 static int spi_acpi_device_match(struct device *dev, void *data)
3180 {
3181         return ACPI_COMPANION(dev) == data;
3182 }
3183
3184 static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3185 {
3186         struct device *dev;
3187
3188         dev = class_find_device(&spi_master_class, NULL, adev,
3189                                 spi_acpi_master_match);
3190         if (!dev)
3191                 return NULL;
3192
3193         return container_of(dev, struct spi_master, dev);
3194 }
3195
3196 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3197 {
3198         struct device *dev;
3199
3200         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3201
3202         return dev ? to_spi_device(dev) : NULL;
3203 }
3204
3205 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3206                            void *arg)
3207 {
3208         struct acpi_device *adev = arg;
3209         struct spi_master *master;
3210         struct spi_device *spi;
3211
3212         switch (value) {
3213         case ACPI_RECONFIG_DEVICE_ADD:
3214                 master = acpi_spi_find_master_by_adev(adev->parent);
3215                 if (!master)
3216                         break;
3217
3218                 acpi_register_spi_device(master, adev);
3219                 put_device(&master->dev);
3220                 break;
3221         case ACPI_RECONFIG_DEVICE_REMOVE:
3222                 if (!acpi_device_enumerated(adev))
3223                         break;
3224
3225                 spi = acpi_spi_find_device_by_adev(adev);
3226                 if (!spi)
3227                         break;
3228
3229                 spi_unregister_device(spi);
3230                 put_device(&spi->dev);
3231                 break;
3232         }
3233
3234         return NOTIFY_OK;
3235 }
3236
3237 static struct notifier_block spi_acpi_notifier = {
3238         .notifier_call = acpi_spi_notify,
3239 };
3240 #else
3241 extern struct notifier_block spi_acpi_notifier;
3242 #endif
3243
3244 static int __init spi_init(void)
3245 {
3246         int     status;
3247
3248         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3249         if (!buf) {
3250                 status = -ENOMEM;
3251                 goto err0;
3252         }
3253
3254         status = bus_register(&spi_bus_type);
3255         if (status < 0)
3256                 goto err1;
3257
3258         status = class_register(&spi_master_class);
3259         if (status < 0)
3260                 goto err2;
3261
3262         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3263                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3264         if (IS_ENABLED(CONFIG_ACPI))
3265                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3266
3267         return 0;
3268
3269 err2:
3270         bus_unregister(&spi_bus_type);
3271 err1:
3272         kfree(buf);
3273         buf = NULL;
3274 err0:
3275         return status;
3276 }
3277
3278 /* board_info is normally registered in arch_initcall(),
3279  * but even essential drivers wait till later
3280  *
3281  * REVISIT only boardinfo really needs static linking. the rest (device and
3282  * driver registration) _could_ be dynamically linked (modular) ... costs
3283  * include needing to have boardinfo data structures be much more public.
3284  */
3285 postcore_initcall(spi_init);
3286