drivers/misc/mic/cosm/cosm_main.c

   1 /*
   2  * Intel MIC Platform Software Stack (MPSS)
   3  *
   4  * Copyright(c) 2015 Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * The full GNU General Public License is included in this distribution in
  16  * the file called "COPYING".
  17  *
  18  * Intel MIC Coprocessor State Management (COSM) Driver
  19  *
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/delay.h>
  24 #include <linux/idr.h>
  25 #include <linux/slab.h>
  26 #include <linux/cred.h>
  27 #include "cosm_main.h"
  28
  29 static const char cosm_driver_name[] = "mic";
  30
  31 /* COSM ID allocator */
  32 static struct ida g_cosm_ida;
  33 /* Class of MIC devices for sysfs accessibility. */
  34 static struct class *g_cosm_class;
  35 /* Number of MIC devices */
  36 static atomic_t g_num_dev;
  37
  38 /**
  39  * cosm_hw_reset - Issue a HW reset for the MIC device
  40  * @cdev: pointer to cosm_device instance
  41  */
  42 static void cosm_hw_reset(struct cosm_device *cdev, bool force)
  43 {
  44         int i;
  45
  46 #define MIC_RESET_TO (45)
  47         if (force && cdev->hw_ops->force_reset)
  48                 cdev->hw_ops->force_reset(cdev);
  49         else
  50                 cdev->hw_ops->reset(cdev);
  51
  52         for (i = 0; i < MIC_RESET_TO; i++) {
  53                 if (cdev->hw_ops->ready(cdev)) {
  54                         cosm_set_state(cdev, MIC_READY);
  55                         return;
  56                 }
  57                 /*
  58                  * Resets typically take 10s of seconds to complete.
  59                  * Since an MMIO read is required to check if the
  60                  * firmware is ready or not, a 1 second delay works nicely.
  61                  */
  62                 msleep(1000);
  63         }
  64         cosm_set_state(cdev, MIC_RESET_FAILED);
  65 }
  66
  67 /**
  68  * cosm_start - Start the MIC
  69  * @cdev: pointer to cosm_device instance
  70  *
  71  * This function prepares an MIC for boot and initiates boot.
  72  * RETURNS: An appropriate -ERRNO error value on error, or 0 for success.
  73  */
  74 int cosm_start(struct cosm_device *cdev)
  75 {
  76         const struct cred *orig_cred;
  77         struct cred *override_cred;
  78         int rc;
  79
  80         mutex_lock(&cdev->cosm_mutex);
  81         if (!cdev->bootmode) {
  82                 dev_err(&cdev->dev, "%s %d bootmode not set\n",
  83                         __func__, __LINE__);
  84                 rc = -EINVAL;
  85                 goto unlock_ret;
  86         }
  87 retry:
  88         if (cdev->state != MIC_READY) {
  89                 dev_err(&cdev->dev, "%s %d MIC state not READY\n",
  90                         __func__, __LINE__);
  91                 rc = -EINVAL;
  92                 goto unlock_ret;
  93         }
  94         if (!cdev->hw_ops->ready(cdev)) {
  95                 cosm_hw_reset(cdev, false);
  96                 /*
  97                  * The state will either be MIC_READY if the reset succeeded
  98                  * or MIC_RESET_FAILED if the firmware reset failed.
  99                  */
 100                 goto retry;
 101         }
 102
 103         /*
 104          * Set credentials to root to allow non-root user to download initramsfs
 105          * with 600 permissions
 106          */
 107         override_cred = prepare_creds();
 108         if (!override_cred) {
 109                 dev_err(&cdev->dev, "%s %d prepare_creds failed\n",
 110                         __func__, __LINE__);
 111                 rc = -ENOMEM;
 112                 goto unlock_ret;
 113         }
 114         override_cred->fsuid = GLOBAL_ROOT_UID;
 115         orig_cred = override_creds(override_cred);
 116
 117         rc = cdev->hw_ops->start(cdev, cdev->index);
 118
 119         revert_creds(orig_cred);
 120         put_cred(override_cred);
 121         if (rc)
 122                 goto unlock_ret;
 123
 124         /*
 125          * If linux is being booted, card is treated 'online' only
 126          * when the scif interface in the card is up. If anything else
 127          * is booted, we set card to 'online' immediately.
 128          */
 129         if (!strcmp(cdev->bootmode, "linux"))
 130                 cosm_set_state(cdev, MIC_BOOTING);
 131         else
 132                 cosm_set_state(cdev, MIC_ONLINE);
 133 unlock_ret:
 134         mutex_unlock(&cdev->cosm_mutex);
 135         if (rc)
 136                 dev_err(&cdev->dev, "cosm_start failed rc %d\n", rc);
 137         return rc;
 138 }
 139
 140 /**
 141  * cosm_stop - Prepare the MIC for reset and trigger reset
 142  * @cdev: pointer to cosm_device instance
 143  * @force: force a MIC to reset even if it is already reset and ready.
 144  *
 145  * RETURNS: None
 146  */
 147 void cosm_stop(struct cosm_device *cdev, bool force)
 148 {
 149         mutex_lock(&cdev->cosm_mutex);
 150         if (cdev->state != MIC_READY || force) {
 151                 /*
 152                  * Don't call hw_ops if they have been called previously.
 153                  * stop(..) calls device_unregister and will crash the system if
 154                  * called multiple times.
 155                  */
 156                 u8 state = cdev->state == MIC_RESETTING ?
 157                                         cdev->prev_state : cdev->state;
 158                 bool call_hw_ops = state != MIC_RESET_FAILED &&
 159                                         state != MIC_READY;
 160
 161                 if (cdev->state != MIC_RESETTING)
 162                         cosm_set_state(cdev, MIC_RESETTING);
 163                 cdev->heartbeat_watchdog_enable = false;
 164                 if (call_hw_ops)
 165                         cdev->hw_ops->stop(cdev, force);
 166                 cosm_hw_reset(cdev, force);
 167                 cosm_set_shutdown_status(cdev, MIC_NOP);
 168                 if (call_hw_ops && cdev->hw_ops->post_reset)
 169                         cdev->hw_ops->post_reset(cdev, cdev->state);
 170         }
 171         mutex_unlock(&cdev->cosm_mutex);
 172         flush_work(&cdev->scif_work);
 173 }
 174
 175 /**
 176  * cosm_reset_trigger_work - Trigger MIC reset
 177  * @work: The work structure
 178  *
 179  * This work is scheduled whenever the host wants to reset the MIC.
 180  */
 181 static void cosm_reset_trigger_work(struct work_struct *work)
 182 {
 183         struct cosm_device *cdev = container_of(work, struct cosm_device,
 184                                                 reset_trigger_work);
 185         cosm_stop(cdev, false);
 186 }
 187
 188 /**
 189  * cosm_reset - Schedule MIC reset
 190  * @cdev: pointer to cosm_device instance
 191  *
 192  * RETURNS: An -EINVAL if the card is already READY or 0 for success.
 193  */
 194 int cosm_reset(struct cosm_device *cdev)
 195 {
 196         int rc = 0;
 197
 198         mutex_lock(&cdev->cosm_mutex);
 199         if (cdev->state != MIC_READY) {
 200                 if (cdev->state != MIC_RESETTING) {
 201                         cdev->prev_state = cdev->state;
 202                         cosm_set_state(cdev, MIC_RESETTING);
 203                         schedule_work(&cdev->reset_trigger_work);
 204                 }
 205         } else {
 206                 dev_err(&cdev->dev, "%s %d MIC is READY\n", __func__, __LINE__);
 207                 rc = -EINVAL;
 208         }
 209         mutex_unlock(&cdev->cosm_mutex);
 210         return rc;
 211 }
 212
 213 /**
 214  * cosm_shutdown - Initiate MIC shutdown.
 215  * @cdev: pointer to cosm_device instance
 216  *
 217  * RETURNS: None
 218  */
 219 int cosm_shutdown(struct cosm_device *cdev)
 220 {
 221         struct cosm_msg msg = { .id = COSM_MSG_SHUTDOWN };
 222         int rc = 0;
 223
 224         mutex_lock(&cdev->cosm_mutex);
 225         if (cdev->state != MIC_ONLINE) {
 226                 rc = -EINVAL;
 227                 dev_err(&cdev->dev, "%s %d skipping shutdown in state: %s\n",
 228                         __func__, __LINE__, cosm_state_string[cdev->state]);
 229                 goto err;
 230         }
 231
 232         if (!cdev->epd) {
 233                 rc = -ENOTCONN;
 234                 dev_err(&cdev->dev, "%s %d scif endpoint not connected rc %d\n",
 235                         __func__, __LINE__, rc);
 236                 goto err;
 237         }
 238
 239         rc = scif_send(cdev->epd, &msg, sizeof(msg), SCIF_SEND_BLOCK);
 240         if (rc < 0) {
 241                 dev_err(&cdev->dev, "%s %d scif_send failed rc %d\n",
 242                         __func__, __LINE__, rc);
 243                 goto err;
 244         }
 245         cdev->heartbeat_watchdog_enable = false;
 246         cosm_set_state(cdev, MIC_SHUTTING_DOWN);
 247         rc = 0;
 248 err:
 249         mutex_unlock(&cdev->cosm_mutex);
 250         return rc;
 251 }
 252
 253 static int cosm_driver_probe(struct cosm_device *cdev)
 254 {
 255         int rc;
 256
 257         /* Initialize SCIF server at first probe */
 258         if (atomic_add_return(1, &g_num_dev) == 1) {
 259                 rc = cosm_scif_init();
 260                 if (rc)
 261                         goto scif_exit;
 262         }
 263         mutex_init(&cdev->cosm_mutex);
 264         INIT_WORK(&cdev->reset_trigger_work, cosm_reset_trigger_work);
 265         INIT_WORK(&cdev->scif_work, cosm_scif_work);
 266         cdev->sysfs_heartbeat_enable = true;
 267         cosm_sysfs_init(cdev);
 268         cdev->sdev = device_create_with_groups(g_cosm_class, cdev->dev.parent,
 269                                MKDEV(0, cdev->index), cdev, cdev->attr_group,
 270                                "mic%d", cdev->index);
 271         if (IS_ERR(cdev->sdev)) {
 272                 rc = PTR_ERR(cdev->sdev);
 273                 dev_err(&cdev->dev, "device_create_with_groups failed rc %d\n",
 274                         rc);
 275                 goto scif_exit;
 276         }
 277
 278         cdev->state_sysfs = sysfs_get_dirent(cdev->sdev->kobj.sd,
 279                 "state");
 280         if (!cdev->state_sysfs) {
 281                 rc = -ENODEV;
 282                 dev_err(&cdev->dev, "sysfs_get_dirent failed rc %d\n", rc);
 283                 goto destroy_device;
 284         }
 285         cosm_create_debug_dir(cdev);
 286         return 0;
 287 destroy_device:
 288         device_destroy(g_cosm_class, MKDEV(0, cdev->index));
 289 scif_exit:
 290         if (atomic_dec_and_test(&g_num_dev))
 291                 cosm_scif_exit();
 292         return rc;
 293 }
 294
 295 static void cosm_driver_remove(struct cosm_device *cdev)
 296 {
 297         cosm_delete_debug_dir(cdev);
 298         sysfs_put(cdev->state_sysfs);
 299         device_destroy(g_cosm_class, MKDEV(0, cdev->index));
 300         flush_work(&cdev->reset_trigger_work);
 301         cosm_stop(cdev, false);
 302         if (atomic_dec_and_test(&g_num_dev))
 303                 cosm_scif_exit();
 304
 305         /* These sysfs entries might have allocated */
 306         kfree(cdev->cmdline);
 307         kfree(cdev->firmware);
 308         kfree(cdev->ramdisk);
 309         kfree(cdev->bootmode);
 310 }
 311
 312 static int cosm_suspend(struct device *dev)
 313 {
 314         struct cosm_device *cdev = dev_to_cosm(dev);
 315
 316         mutex_lock(&cdev->cosm_mutex);
 317         switch (cdev->state) {
 318         /**
 319          * Suspend/freeze hooks in userspace have already shutdown the card.
 320          * Card should be 'ready' in most cases. It is however possible that
 321          * some userspace application initiated a boot. In those cases, we
 322          * simply reset the card.
 323          */
 324         case MIC_ONLINE:
 325         case MIC_BOOTING:
 326         case MIC_SHUTTING_DOWN:
 327                 mutex_unlock(&cdev->cosm_mutex);
 328                 cosm_stop(cdev, false);
 329                 break;
 330         default:
 331                 mutex_unlock(&cdev->cosm_mutex);
 332                 break;
 333         }
 334         return 0;
 335 }
 336
 337 static const struct dev_pm_ops cosm_pm_ops = {
 338         .suspend = cosm_suspend,
 339         .freeze = cosm_suspend
 340 };
 341
 342 static struct cosm_driver cosm_driver = {
 343         .driver = {
 344                 .name =  KBUILD_MODNAME,
 345                 .owner = THIS_MODULE,
 346                 .pm = &cosm_pm_ops,
 347         },
 348         .probe = cosm_driver_probe,
 349         .remove = cosm_driver_remove
 350 };
 351
 352 static int __init cosm_init(void)
 353 {
 354         int ret;
 355
 356         cosm_init_debugfs();
 357
 358         g_cosm_class = class_create(THIS_MODULE, cosm_driver_name);
 359         if (IS_ERR(g_cosm_class)) {
 360                 ret = PTR_ERR(g_cosm_class);
 361                 pr_err("class_create failed ret %d\n", ret);
 362                 goto cleanup_debugfs;
 363         }
 364
 365         ida_init(&g_cosm_ida);
 366         ret = cosm_register_driver(&cosm_driver);
 367         if (ret) {
 368                 pr_err("cosm_register_driver failed ret %d\n", ret);
 369                 goto ida_destroy;
 370         }
 371         return 0;
 372 ida_destroy:
 373         ida_destroy(&g_cosm_ida);
 374         class_destroy(g_cosm_class);
 375 cleanup_debugfs:
 376         cosm_exit_debugfs();
 377         return ret;
 378 }
 379
 380 static void __exit cosm_exit(void)
 381 {
 382         cosm_unregister_driver(&cosm_driver);
 383         ida_destroy(&g_cosm_ida);
 384         class_destroy(g_cosm_class);
 385         cosm_exit_debugfs();
 386 }
 387
 388 module_init(cosm_init);
 389 module_exit(cosm_exit);
 390
 391 MODULE_AUTHOR("Intel Corporation");
 392 MODULE_DESCRIPTION("Intel(R) MIC Coprocessor State Management (COSM) Driver");
 393 MODULE_LICENSE("GPL v2");