drivers/staging/greybus/uart.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * UART driver for the Greybus "generic" UART module.
   4  *
   5  * Copyright 2014 Google Inc.
   6  * Copyright 2014 Linaro Ltd.
   7  *
   8  * Heavily based on drivers/usb/class/cdc-acm.c and
   9  * drivers/usb/serial/usb-serial.c.
  10  */
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/kernel.h>
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched/signal.h>
  17 #include <linux/wait.h>
  18 #include <linux/slab.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/mutex.h>
  21 #include <linux/tty.h>
  22 #include <linux/serial.h>
  23 #include <linux/tty_driver.h>
  24 #include <linux/tty_flip.h>
  25 #include <linux/idr.h>
  26 #include <linux/fs.h>
  27 #include <linux/kdev_t.h>
  28 #include <linux/kfifo.h>
  29 #include <linux/workqueue.h>
  30 #include <linux/completion.h>
  31
  32 #include "greybus.h"
  33 #include "gbphy.h"
  34
  35 #define GB_NUM_MINORS   16      /* 16 is more than enough */
  36 #define GB_NAME         "ttyGB"
  37
  38 #define GB_UART_WRITE_FIFO_SIZE         PAGE_SIZE
  39 #define GB_UART_WRITE_ROOM_MARGIN       1       /* leave some space in fifo */
  40 #define GB_UART_FIRMWARE_CREDITS        4096
  41 #define GB_UART_CREDIT_WAIT_TIMEOUT_MSEC        10000
  42
  43 struct gb_tty_line_coding {
  44         __le32  rate;
  45         __u8    format;
  46         __u8    parity;
  47         __u8    data_bits;
  48         __u8    flow_control;
  49 };
  50
  51 struct gb_tty {
  52         struct gbphy_device *gbphy_dev;
  53         struct tty_port port;
  54         void *buffer;
  55         size_t buffer_payload_max;
  56         struct gb_connection *connection;
  57         u16 cport_id;
  58         unsigned int minor;
  59         unsigned char clocal;
  60         bool disconnected;
  61         spinlock_t read_lock;
  62         spinlock_t write_lock;
  63         struct async_icount iocount;
  64         struct async_icount oldcount;
  65         wait_queue_head_t wioctl;
  66         struct mutex mutex;
  67         u8 ctrlin;      /* input control lines */
  68         u8 ctrlout;     /* output control lines */
  69         struct gb_tty_line_coding line_coding;
  70         struct work_struct tx_work;
  71         struct kfifo write_fifo;
  72         bool close_pending;
  73         unsigned int credits;
  74         struct completion credits_complete;
  75 };
  76
  77 static struct tty_driver *gb_tty_driver;
  78 static DEFINE_IDR(tty_minors);
  79 static DEFINE_MUTEX(table_lock);
  80
  81 static int gb_uart_receive_data_handler(struct gb_operation *op)
  82 {
  83         struct gb_connection *connection = op->connection;
  84         struct gb_tty *gb_tty = gb_connection_get_data(connection);
  85         struct tty_port *port = &gb_tty->port;
  86         struct gb_message *request = op->request;
  87         struct gb_uart_recv_data_request *receive_data;
  88         u16 recv_data_size;
  89         int count;
  90         unsigned long tty_flags = TTY_NORMAL;
  91
  92         if (request->payload_size < sizeof(*receive_data)) {
  93                 dev_err(&gb_tty->gbphy_dev->dev,
  94                         "short receive-data request received (%zu < %zu)\n",
  95                         request->payload_size, sizeof(*receive_data));
  96                 return -EINVAL;
  97         }
  98
  99         receive_data = op->request->payload;
 100         recv_data_size = le16_to_cpu(receive_data->size);
 101
 102         if (recv_data_size != request->payload_size - sizeof(*receive_data)) {
 103                 dev_err(&gb_tty->gbphy_dev->dev,
 104                         "malformed receive-data request received (%u != %zu)\n",
 105                         recv_data_size,
 106                         request->payload_size - sizeof(*receive_data));
 107                 return -EINVAL;
 108         }
 109
 110         if (!recv_data_size)
 111                 return -EINVAL;
 112
 113         if (receive_data->flags) {
 114                 if (receive_data->flags & GB_UART_RECV_FLAG_BREAK)
 115                         tty_flags = TTY_BREAK;
 116                 else if (receive_data->flags & GB_UART_RECV_FLAG_PARITY)
 117                         tty_flags = TTY_PARITY;
 118                 else if (receive_data->flags & GB_UART_RECV_FLAG_FRAMING)
 119                         tty_flags = TTY_FRAME;
 120
 121                 /* overrun is special, not associated with a char */
 122                 if (receive_data->flags & GB_UART_RECV_FLAG_OVERRUN)
 123                         tty_insert_flip_char(port, 0, TTY_OVERRUN);
 124         }
 125         count = tty_insert_flip_string_fixed_flag(port, receive_data->data,
 126                                                   tty_flags, recv_data_size);
 127         if (count != recv_data_size) {
 128                 dev_err(&gb_tty->gbphy_dev->dev,
 129                         "UART: RX 0x%08x bytes only wrote 0x%08x\n",
 130                         recv_data_size, count);
 131         }
 132         if (count)
 133                 tty_flip_buffer_push(port);
 134         return 0;
 135 }
 136
 137 static int gb_uart_serial_state_handler(struct gb_operation *op)
 138 {
 139         struct gb_connection *connection = op->connection;
 140         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 141         struct gb_message *request = op->request;
 142         struct gb_uart_serial_state_request *serial_state;
 143
 144         if (request->payload_size < sizeof(*serial_state)) {
 145                 dev_err(&gb_tty->gbphy_dev->dev,
 146                         "short serial-state event received (%zu < %zu)\n",
 147                         request->payload_size, sizeof(*serial_state));
 148                 return -EINVAL;
 149         }
 150
 151         serial_state = request->payload;
 152         gb_tty->ctrlin = serial_state->control;
 153
 154         return 0;
 155 }
 156
 157 static int gb_uart_receive_credits_handler(struct gb_operation *op)
 158 {
 159         struct gb_connection *connection = op->connection;
 160         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 161         struct gb_message *request = op->request;
 162         struct gb_uart_receive_credits_request *credit_request;
 163         unsigned long flags;
 164         unsigned int incoming_credits;
 165         int ret = 0;
 166
 167         if (request->payload_size < sizeof(*credit_request)) {
 168                 dev_err(&gb_tty->gbphy_dev->dev,
 169                         "short receive_credits event received (%zu < %zu)\n",
 170                         request->payload_size,
 171                         sizeof(*credit_request));
 172                 return -EINVAL;
 173         }
 174
 175         credit_request = request->payload;
 176         incoming_credits = le16_to_cpu(credit_request->count);
 177
 178         spin_lock_irqsave(&gb_tty->write_lock, flags);
 179         gb_tty->credits += incoming_credits;
 180         if (gb_tty->credits > GB_UART_FIRMWARE_CREDITS) {
 181                 gb_tty->credits -= incoming_credits;
 182                 ret = -EINVAL;
 183         }
 184         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 185
 186         if (ret) {
 187                 dev_err(&gb_tty->gbphy_dev->dev,
 188                         "invalid number of incoming credits: %d\n",
 189                         incoming_credits);
 190                 return ret;
 191         }
 192
 193         if (!gb_tty->close_pending)
 194                 schedule_work(&gb_tty->tx_work);
 195
 196         /*
 197          * the port the tty layer may be waiting for credits
 198          */
 199         tty_port_tty_wakeup(&gb_tty->port);
 200
 201         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 202                 complete(&gb_tty->credits_complete);
 203
 204         return ret;
 205 }
 206
 207 static int gb_uart_request_handler(struct gb_operation *op)
 208 {
 209         struct gb_connection *connection = op->connection;
 210         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 211         int type = op->type;
 212         int ret;
 213
 214         switch (type) {
 215         case GB_UART_TYPE_RECEIVE_DATA:
 216                 ret = gb_uart_receive_data_handler(op);
 217                 break;
 218         case GB_UART_TYPE_SERIAL_STATE:
 219                 ret = gb_uart_serial_state_handler(op);
 220                 break;
 221         case GB_UART_TYPE_RECEIVE_CREDITS:
 222                 ret = gb_uart_receive_credits_handler(op);
 223                 break;
 224         default:
 225                 dev_err(&gb_tty->gbphy_dev->dev,
 226                         "unsupported unsolicited request: 0x%02x\n", type);
 227                 ret = -EINVAL;
 228         }
 229
 230         return ret;
 231 }
 232
 233 static void  gb_uart_tx_write_work(struct work_struct *work)
 234 {
 235         struct gb_uart_send_data_request *request;
 236         struct gb_tty *gb_tty;
 237         unsigned long flags;
 238         unsigned int send_size;
 239         int ret;
 240
 241         gb_tty = container_of(work, struct gb_tty, tx_work);
 242         request = gb_tty->buffer;
 243
 244         while (1) {
 245                 if (gb_tty->close_pending)
 246                         break;
 247
 248                 spin_lock_irqsave(&gb_tty->write_lock, flags);
 249                 send_size = gb_tty->buffer_payload_max;
 250                 if (send_size > gb_tty->credits)
 251                         send_size = gb_tty->credits;
 252
 253                 send_size = kfifo_out_peek(&gb_tty->write_fifo,
 254                                            &request->data[0],
 255                                            send_size);
 256                 if (!send_size) {
 257                         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 258                         break;
 259                 }
 260
 261                 gb_tty->credits -= send_size;
 262                 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 263
 264                 request->size = cpu_to_le16(send_size);
 265                 ret = gb_operation_sync(gb_tty->connection,
 266                                         GB_UART_TYPE_SEND_DATA,
 267                                         request, sizeof(*request) + send_size,
 268                                         NULL, 0);
 269                 if (ret) {
 270                         dev_err(&gb_tty->gbphy_dev->dev,
 271                                 "send data error: %d\n", ret);
 272                         spin_lock_irqsave(&gb_tty->write_lock, flags);
 273                         gb_tty->credits += send_size;
 274                         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 275                         if (!gb_tty->close_pending)
 276                                 schedule_work(work);
 277                         return;
 278                 }
 279
 280                 spin_lock_irqsave(&gb_tty->write_lock, flags);
 281                 ret = kfifo_out(&gb_tty->write_fifo, &request->data[0],
 282                                 send_size);
 283                 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 284
 285                 tty_port_tty_wakeup(&gb_tty->port);
 286         }
 287 }
 288
 289 static int send_line_coding(struct gb_tty *tty)
 290 {
 291         struct gb_uart_set_line_coding_request request;
 292
 293         memcpy(&request, &tty->line_coding,
 294                sizeof(tty->line_coding));
 295         return gb_operation_sync(tty->connection, GB_UART_TYPE_SET_LINE_CODING,
 296                                  &request, sizeof(request), NULL, 0);
 297 }
 298
 299 static int send_control(struct gb_tty *gb_tty, u8 control)
 300 {
 301         struct gb_uart_set_control_line_state_request request;
 302
 303         request.control = control;
 304         return gb_operation_sync(gb_tty->connection,
 305                                  GB_UART_TYPE_SET_CONTROL_LINE_STATE,
 306                                  &request, sizeof(request), NULL, 0);
 307 }
 308
 309 static int send_break(struct gb_tty *gb_tty, u8 state)
 310 {
 311         struct gb_uart_set_break_request request;
 312
 313         if ((state != 0) && (state != 1)) {
 314                 dev_err(&gb_tty->gbphy_dev->dev,
 315                         "invalid break state of %d\n", state);
 316                 return -EINVAL;
 317         }
 318
 319         request.state = state;
 320         return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_SEND_BREAK,
 321                                  &request, sizeof(request), NULL, 0);
 322 }
 323
 324 static int gb_uart_wait_for_all_credits(struct gb_tty *gb_tty)
 325 {
 326         int ret;
 327
 328         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 329                 return 0;
 330
 331         ret = wait_for_completion_timeout(&gb_tty->credits_complete,
 332                         msecs_to_jiffies(GB_UART_CREDIT_WAIT_TIMEOUT_MSEC));
 333         if (!ret) {
 334                 dev_err(&gb_tty->gbphy_dev->dev,
 335                         "time out waiting for credits\n");
 336                 return -ETIMEDOUT;
 337         }
 338
 339         return 0;
 340 }
 341
 342 static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
 343 {
 344         struct gb_uart_serial_flush_request request;
 345
 346         request.flags = flags;
 347         return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_FLUSH_FIFOS,
 348                                  &request, sizeof(request), NULL, 0);
 349 }
 350
 351 static struct gb_tty *get_gb_by_minor(unsigned int minor)
 352 {
 353         struct gb_tty *gb_tty;
 354
 355         mutex_lock(&table_lock);
 356         gb_tty = idr_find(&tty_minors, minor);
 357         if (gb_tty) {
 358                 mutex_lock(&gb_tty->mutex);
 359                 if (gb_tty->disconnected) {
 360                         mutex_unlock(&gb_tty->mutex);
 361                         gb_tty = NULL;
 362                 } else {
 363                         tty_port_get(&gb_tty->port);
 364                         mutex_unlock(&gb_tty->mutex);
 365                 }
 366         }
 367         mutex_unlock(&table_lock);
 368         return gb_tty;
 369 }
 370
 371 static int alloc_minor(struct gb_tty *gb_tty)
 372 {
 373         int minor;
 374
 375         mutex_lock(&table_lock);
 376         minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
 377         mutex_unlock(&table_lock);
 378         if (minor >= 0)
 379                 gb_tty->minor = minor;
 380         return minor;
 381 }
 382
 383 static void release_minor(struct gb_tty *gb_tty)
 384 {
 385         int minor = gb_tty->minor;
 386
 387         gb_tty->minor = 0;      /* Maybe should use an invalid value instead */
 388         mutex_lock(&table_lock);
 389         idr_remove(&tty_minors, minor);
 390         mutex_unlock(&table_lock);
 391 }
 392
 393 static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty)
 394 {
 395         struct gb_tty *gb_tty;
 396         int retval;
 397
 398         gb_tty = get_gb_by_minor(tty->index);
 399         if (!gb_tty)
 400                 return -ENODEV;
 401
 402         retval = tty_standard_install(driver, tty);
 403         if (retval)
 404                 goto error;
 405
 406         tty->driver_data = gb_tty;
 407         return 0;
 408 error:
 409         tty_port_put(&gb_tty->port);
 410         return retval;
 411 }
 412
 413 static int gb_tty_open(struct tty_struct *tty, struct file *file)
 414 {
 415         struct gb_tty *gb_tty = tty->driver_data;
 416
 417         return tty_port_open(&gb_tty->port, tty, file);
 418 }
 419
 420 static void gb_tty_close(struct tty_struct *tty, struct file *file)
 421 {
 422         struct gb_tty *gb_tty = tty->driver_data;
 423
 424         tty_port_close(&gb_tty->port, tty, file);
 425 }
 426
 427 static void gb_tty_cleanup(struct tty_struct *tty)
 428 {
 429         struct gb_tty *gb_tty = tty->driver_data;
 430
 431         tty_port_put(&gb_tty->port);
 432 }
 433
 434 static void gb_tty_hangup(struct tty_struct *tty)
 435 {
 436         struct gb_tty *gb_tty = tty->driver_data;
 437
 438         tty_port_hangup(&gb_tty->port);
 439 }
 440
 441 static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
 442                         int count)
 443 {
 444         struct gb_tty *gb_tty = tty->driver_data;
 445
 446         count =  kfifo_in_spinlocked(&gb_tty->write_fifo, buf, count,
 447                                      &gb_tty->write_lock);
 448         if (count && !gb_tty->close_pending)
 449                 schedule_work(&gb_tty->tx_work);
 450
 451         return count;
 452 }
 453
 454 static int gb_tty_write_room(struct tty_struct *tty)
 455 {
 456         struct gb_tty *gb_tty = tty->driver_data;
 457         unsigned long flags;
 458         int room;
 459
 460         spin_lock_irqsave(&gb_tty->write_lock, flags);
 461         room = kfifo_avail(&gb_tty->write_fifo);
 462         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 463
 464         room -= GB_UART_WRITE_ROOM_MARGIN;
 465         if (room < 0)
 466                 return 0;
 467
 468         return room;
 469 }
 470
 471 static int gb_tty_chars_in_buffer(struct tty_struct *tty)
 472 {
 473         struct gb_tty *gb_tty = tty->driver_data;
 474         unsigned long flags;
 475         int chars;
 476
 477         spin_lock_irqsave(&gb_tty->write_lock, flags);
 478         chars = kfifo_len(&gb_tty->write_fifo);
 479         if (gb_tty->credits < GB_UART_FIRMWARE_CREDITS)
 480                 chars += GB_UART_FIRMWARE_CREDITS - gb_tty->credits;
 481         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 482
 483         return chars;
 484 }
 485
 486 static int gb_tty_break_ctl(struct tty_struct *tty, int state)
 487 {
 488         struct gb_tty *gb_tty = tty->driver_data;
 489
 490         return send_break(gb_tty, state ? 1 : 0);
 491 }
 492
 493 static void gb_tty_set_termios(struct tty_struct *tty,
 494                                struct ktermios *termios_old)
 495 {
 496         struct gb_tty *gb_tty = tty->driver_data;
 497         struct ktermios *termios = &tty->termios;
 498         struct gb_tty_line_coding newline;
 499         u8 newctrl = gb_tty->ctrlout;
 500
 501         newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
 502         newline.format = termios->c_cflag & CSTOPB ?
 503                                 GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
 504         newline.parity = termios->c_cflag & PARENB ?
 505                                 (termios->c_cflag & PARODD ? 1 : 2) +
 506                                 (termios->c_cflag & CMSPAR ? 2 : 0) : 0;
 507
 508         switch (termios->c_cflag & CSIZE) {
 509         case CS5:
 510                 newline.data_bits = 5;
 511                 break;
 512         case CS6:
 513                 newline.data_bits = 6;
 514                 break;
 515         case CS7:
 516                 newline.data_bits = 7;
 517                 break;
 518         case CS8:
 519         default:
 520                 newline.data_bits = 8;
 521                 break;
 522         }
 523
 524         /* FIXME: needs to clear unsupported bits in the termios */
 525         gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
 526
 527         if (C_BAUD(tty) == B0) {
 528                 newline.rate = gb_tty->line_coding.rate;
 529                 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 530         } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
 531                 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 532         }
 533
 534         if (newctrl != gb_tty->ctrlout) {
 535                 gb_tty->ctrlout = newctrl;
 536                 send_control(gb_tty, newctrl);
 537         }
 538
 539         if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
 540                 newline.flow_control |= GB_SERIAL_AUTO_RTSCTS_EN;
 541         else
 542                 newline.flow_control &= ~GB_SERIAL_AUTO_RTSCTS_EN;
 543
 544         if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
 545                 memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
 546                 send_line_coding(gb_tty);
 547         }
 548 }
 549
 550 static int gb_tty_tiocmget(struct tty_struct *tty)
 551 {
 552         struct gb_tty *gb_tty = tty->driver_data;
 553
 554         return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
 555                (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
 556                (gb_tty->ctrlin  & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
 557                (gb_tty->ctrlin  & GB_UART_CTRL_RI  ? TIOCM_RI  : 0) |
 558                (gb_tty->ctrlin  & GB_UART_CTRL_DCD ? TIOCM_CD  : 0) |
 559                TIOCM_CTS;
 560 }
 561
 562 static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
 563                            unsigned int clear)
 564 {
 565         struct gb_tty *gb_tty = tty->driver_data;
 566         u8 newctrl = gb_tty->ctrlout;
 567
 568         set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
 569               (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
 570         clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
 571                 (clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
 572
 573         newctrl = (newctrl & ~clear) | set;
 574         if (gb_tty->ctrlout == newctrl)
 575                 return 0;
 576
 577         gb_tty->ctrlout = newctrl;
 578         return send_control(gb_tty, newctrl);
 579 }
 580
 581 static void gb_tty_throttle(struct tty_struct *tty)
 582 {
 583         struct gb_tty *gb_tty = tty->driver_data;
 584         unsigned char stop_char;
 585         int retval;
 586
 587         if (I_IXOFF(tty)) {
 588                 stop_char = STOP_CHAR(tty);
 589                 retval = gb_tty_write(tty, &stop_char, 1);
 590                 if (retval <= 0)
 591                         return;
 592         }
 593
 594         if (tty->termios.c_cflag & CRTSCTS) {
 595                 gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
 596                 retval = send_control(gb_tty, gb_tty->ctrlout);
 597         }
 598 }
 599
 600 static void gb_tty_unthrottle(struct tty_struct *tty)
 601 {
 602         struct gb_tty *gb_tty = tty->driver_data;
 603         unsigned char start_char;
 604         int retval;
 605
 606         if (I_IXOFF(tty)) {
 607                 start_char = START_CHAR(tty);
 608                 retval = gb_tty_write(tty, &start_char, 1);
 609                 if (retval <= 0)
 610                         return;
 611         }
 612
 613         if (tty->termios.c_cflag & CRTSCTS) {
 614                 gb_tty->ctrlout |= GB_UART_CTRL_RTS;
 615                 retval = send_control(gb_tty, gb_tty->ctrlout);
 616         }
 617 }
 618
 619 static int get_serial_info(struct tty_struct *tty,
 620                            struct serial_struct *ss)
 621 {
 622         struct gb_tty *gb_tty = tty->driver_data;
 623
 624         ss->type = PORT_16550A;
 625         ss->line = gb_tty->minor;
 626         ss->xmit_fifo_size = 16;
 627         ss->baud_base = 9600;
 628         ss->close_delay = gb_tty->port.close_delay / 10;
 629         ss->closing_wait =
 630                 gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 631                 ASYNC_CLOSING_WAIT_NONE : gb_tty->port.closing_wait / 10;
 632         return 0;
 633 }
 634
 635 static int set_serial_info(struct tty_struct *tty,
 636                            struct serial_struct *ss)
 637 {
 638         struct gb_tty *gb_tty = tty->driver_data;
 639         unsigned int closing_wait;
 640         unsigned int close_delay;
 641         int retval = 0;
 642
 643         close_delay = ss->close_delay * 10;
 644         closing_wait = ss->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 645                         ASYNC_CLOSING_WAIT_NONE : ss->closing_wait * 10;
 646
 647         mutex_lock(&gb_tty->port.mutex);
 648         if (!capable(CAP_SYS_ADMIN)) {
 649                 if ((close_delay != gb_tty->port.close_delay) ||
 650                     (closing_wait != gb_tty->port.closing_wait))
 651                         retval = -EPERM;
 652                 else
 653                         retval = -EOPNOTSUPP;
 654         } else {
 655                 gb_tty->port.close_delay = close_delay;
 656                 gb_tty->port.closing_wait = closing_wait;
 657         }
 658         mutex_unlock(&gb_tty->port.mutex);
 659         return retval;
 660 }
 661
 662 static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
 663 {
 664         int retval = 0;
 665         DECLARE_WAITQUEUE(wait, current);
 666         struct async_icount old;
 667         struct async_icount new;
 668
 669         if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
 670                 return -EINVAL;
 671
 672         do {
 673                 spin_lock_irq(&gb_tty->read_lock);
 674                 old = gb_tty->oldcount;
 675                 new = gb_tty->iocount;
 676                 gb_tty->oldcount = new;
 677                 spin_unlock_irq(&gb_tty->read_lock);
 678
 679                 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
 680                         break;
 681                 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
 682                         break;
 683                 if ((arg & TIOCM_RI) && (old.rng != new.rng))
 684                         break;
 685
 686                 add_wait_queue(&gb_tty->wioctl, &wait);
 687                 set_current_state(TASK_INTERRUPTIBLE);
 688                 schedule();
 689                 remove_wait_queue(&gb_tty->wioctl, &wait);
 690                 if (gb_tty->disconnected) {
 691                         if (arg & TIOCM_CD)
 692                                 break;
 693                         retval = -ENODEV;
 694                 } else if (signal_pending(current)) {
 695                         retval = -ERESTARTSYS;
 696                 }
 697         } while (!retval);
 698
 699         return retval;
 700 }
 701
 702 static int gb_tty_get_icount(struct tty_struct *tty,
 703                              struct serial_icounter_struct *icount)
 704 {
 705         struct gb_tty *gb_tty = tty->driver_data;
 706
 707         icount->dsr = gb_tty->iocount.dsr;
 708         icount->rng = gb_tty->iocount.rng;
 709         icount->dcd = gb_tty->iocount.dcd;
 710         icount->frame = gb_tty->iocount.frame;
 711         icount->overrun = gb_tty->iocount.overrun;
 712         icount->parity = gb_tty->iocount.parity;
 713         icount->brk = gb_tty->iocount.brk;
 714
 715         return 0;
 716 }
 717
 718 static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
 719                         unsigned long arg)
 720 {
 721         struct gb_tty *gb_tty = tty->driver_data;
 722
 723         switch (cmd) {
 724         case TIOCMIWAIT:
 725                 return wait_serial_change(gb_tty, arg);
 726         }
 727
 728         return -ENOIOCTLCMD;
 729 }
 730
 731 static void gb_tty_dtr_rts(struct tty_port *port, int on)
 732 {
 733         struct gb_tty *gb_tty;
 734         u8 newctrl;
 735
 736         gb_tty = container_of(port, struct gb_tty, port);
 737         newctrl = gb_tty->ctrlout;
 738
 739         if (on)
 740                 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 741         else
 742                 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 743
 744         gb_tty->ctrlout = newctrl;
 745         send_control(gb_tty, newctrl);
 746 }
 747
 748 static int gb_tty_port_activate(struct tty_port *port,
 749                                 struct tty_struct *tty)
 750 {
 751         struct gb_tty *gb_tty;
 752
 753         gb_tty = container_of(port, struct gb_tty, port);
 754
 755         return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
 756 }
 757
 758 static void gb_tty_port_shutdown(struct tty_port *port)
 759 {
 760         struct gb_tty *gb_tty;
 761         unsigned long flags;
 762         int ret;
 763
 764         gb_tty = container_of(port, struct gb_tty, port);
 765
 766         gb_tty->close_pending = true;
 767
 768         cancel_work_sync(&gb_tty->tx_work);
 769
 770         spin_lock_irqsave(&gb_tty->write_lock, flags);
 771         kfifo_reset_out(&gb_tty->write_fifo);
 772         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 773
 774         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 775                 goto out;
 776
 777         ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
 778         if (ret) {
 779                 dev_err(&gb_tty->gbphy_dev->dev,
 780                         "error flushing transmitter: %d\n", ret);
 781         }
 782
 783         gb_uart_wait_for_all_credits(gb_tty);
 784
 785 out:
 786         gb_tty->close_pending = false;
 787
 788         gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
 789 }
 790
 791 static const struct tty_operations gb_ops = {
 792         .install =              gb_tty_install,
 793         .open =                 gb_tty_open,
 794         .close =                gb_tty_close,
 795         .cleanup =              gb_tty_cleanup,
 796         .hangup =               gb_tty_hangup,
 797         .write =                gb_tty_write,
 798         .write_room =           gb_tty_write_room,
 799         .ioctl =                gb_tty_ioctl,
 800         .throttle =             gb_tty_throttle,
 801         .unthrottle =           gb_tty_unthrottle,
 802         .chars_in_buffer =      gb_tty_chars_in_buffer,
 803         .break_ctl =            gb_tty_break_ctl,
 804         .set_termios =          gb_tty_set_termios,
 805         .tiocmget =             gb_tty_tiocmget,
 806         .tiocmset =             gb_tty_tiocmset,
 807         .get_icount =           gb_tty_get_icount,
 808         .set_serial =           set_serial_info,
 809         .get_serial =           get_serial_info,
 810 };
 811
 812 static const struct tty_port_operations gb_port_ops = {
 813         .dtr_rts =              gb_tty_dtr_rts,
 814         .activate =             gb_tty_port_activate,
 815         .shutdown =             gb_tty_port_shutdown,
 816 };
 817
 818 static int gb_uart_probe(struct gbphy_device *gbphy_dev,
 819                          const struct gbphy_device_id *id)
 820 {
 821         struct gb_connection *connection;
 822         size_t max_payload;
 823         struct gb_tty *gb_tty;
 824         struct device *tty_dev;
 825         int retval;
 826         int minor;
 827
 828         gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
 829         if (!gb_tty)
 830                 return -ENOMEM;
 831
 832         connection = gb_connection_create(gbphy_dev->bundle,
 833                                           le16_to_cpu(gbphy_dev->cport_desc->id),
 834                                           gb_uart_request_handler);
 835         if (IS_ERR(connection)) {
 836                 retval = PTR_ERR(connection);
 837                 goto exit_tty_free;
 838         }
 839
 840         max_payload = gb_operation_get_payload_size_max(connection);
 841         if (max_payload < sizeof(struct gb_uart_send_data_request)) {
 842                 retval = -EINVAL;
 843                 goto exit_connection_destroy;
 844         }
 845
 846         gb_tty->buffer_payload_max = max_payload -
 847                         sizeof(struct gb_uart_send_data_request);
 848
 849         gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
 850         if (!gb_tty->buffer) {
 851                 retval = -ENOMEM;
 852                 goto exit_connection_destroy;
 853         }
 854
 855         INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
 856
 857         retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
 858                              GFP_KERNEL);
 859         if (retval)
 860                 goto exit_buf_free;
 861
 862         gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
 863         init_completion(&gb_tty->credits_complete);
 864
 865         minor = alloc_minor(gb_tty);
 866         if (minor < 0) {
 867                 if (minor == -ENOSPC) {
 868                         dev_err(&gbphy_dev->dev,
 869                                 "no more free minor numbers\n");
 870                         retval = -ENODEV;
 871                 } else {
 872                         retval = minor;
 873                 }
 874                 goto exit_kfifo_free;
 875         }
 876
 877         gb_tty->minor = minor;
 878         spin_lock_init(&gb_tty->write_lock);
 879         spin_lock_init(&gb_tty->read_lock);
 880         init_waitqueue_head(&gb_tty->wioctl);
 881         mutex_init(&gb_tty->mutex);
 882
 883         tty_port_init(&gb_tty->port);
 884         gb_tty->port.ops = &gb_port_ops;
 885
 886         gb_tty->connection = connection;
 887         gb_tty->gbphy_dev = gbphy_dev;
 888         gb_connection_set_data(connection, gb_tty);
 889         gb_gbphy_set_data(gbphy_dev, gb_tty);
 890
 891         retval = gb_connection_enable_tx(connection);
 892         if (retval)
 893                 goto exit_release_minor;
 894
 895         send_control(gb_tty, gb_tty->ctrlout);
 896
 897         /* initialize the uart to be 9600n81 */
 898         gb_tty->line_coding.rate = cpu_to_le32(9600);
 899         gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
 900         gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
 901         gb_tty->line_coding.data_bits = 8;
 902         send_line_coding(gb_tty);
 903
 904         retval = gb_connection_enable(connection);
 905         if (retval)
 906                 goto exit_connection_disable;
 907
 908         tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
 909                                            &gbphy_dev->dev);
 910         if (IS_ERR(tty_dev)) {
 911                 retval = PTR_ERR(tty_dev);
 912                 goto exit_connection_disable;
 913         }
 914
 915         gbphy_runtime_put_autosuspend(gbphy_dev);
 916         return 0;
 917
 918 exit_connection_disable:
 919         gb_connection_disable(connection);
 920 exit_release_minor:
 921         release_minor(gb_tty);
 922 exit_kfifo_free:
 923         kfifo_free(&gb_tty->write_fifo);
 924 exit_buf_free:
 925         kfree(gb_tty->buffer);
 926 exit_connection_destroy:
 927         gb_connection_destroy(connection);
 928 exit_tty_free:
 929         kfree(gb_tty);
 930
 931         return retval;
 932 }
 933
 934 static void gb_uart_remove(struct gbphy_device *gbphy_dev)
 935 {
 936         struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
 937         struct gb_connection *connection = gb_tty->connection;
 938         struct tty_struct *tty;
 939         int ret;
 940
 941         ret = gbphy_runtime_get_sync(gbphy_dev);
 942         if (ret)
 943                 gbphy_runtime_get_noresume(gbphy_dev);
 944
 945         mutex_lock(&gb_tty->mutex);
 946         gb_tty->disconnected = true;
 947
 948         wake_up_all(&gb_tty->wioctl);
 949         mutex_unlock(&gb_tty->mutex);
 950
 951         tty = tty_port_tty_get(&gb_tty->port);
 952         if (tty) {
 953                 tty_vhangup(tty);
 954                 tty_kref_put(tty);
 955         }
 956
 957         gb_connection_disable_rx(connection);
 958         tty_unregister_device(gb_tty_driver, gb_tty->minor);
 959
 960         /* FIXME - free transmit / receive buffers */
 961
 962         gb_connection_disable(connection);
 963         tty_port_destroy(&gb_tty->port);
 964         gb_connection_destroy(connection);
 965         release_minor(gb_tty);
 966         kfifo_free(&gb_tty->write_fifo);
 967         kfree(gb_tty->buffer);
 968         kfree(gb_tty);
 969 }
 970
 971 static int gb_tty_init(void)
 972 {
 973         int retval = 0;
 974
 975         gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
 976         if (IS_ERR(gb_tty_driver)) {
 977                 pr_err("Can not allocate tty driver\n");
 978                 retval = -ENOMEM;
 979                 goto fail_unregister_dev;
 980         }
 981
 982         gb_tty_driver->driver_name = "gb";
 983         gb_tty_driver->name = GB_NAME;
 984         gb_tty_driver->major = 0;
 985         gb_tty_driver->minor_start = 0;
 986         gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
 987         gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
 988         gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 989         gb_tty_driver->init_termios = tty_std_termios;
 990         gb_tty_driver->init_termios.c_cflag = B9600 | CS8 |
 991                 CREAD | HUPCL | CLOCAL;
 992         tty_set_operations(gb_tty_driver, &gb_ops);
 993
 994         retval = tty_register_driver(gb_tty_driver);
 995         if (retval) {
 996                 pr_err("Can not register tty driver: %d\n", retval);
 997                 goto fail_put_gb_tty;
 998         }
 999
1000         return 0;
1001
1002 fail_put_gb_tty:
1003         put_tty_driver(gb_tty_driver);
1004 fail_unregister_dev:
1005         return retval;
1006 }
1007
1008 static void gb_tty_exit(void)
1009 {
1010         tty_unregister_driver(gb_tty_driver);
1011         put_tty_driver(gb_tty_driver);
1012         idr_destroy(&tty_minors);
1013 }
1014
1015 static const struct gbphy_device_id gb_uart_id_table[] = {
1016         { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
1017         { },
1018 };
1019 MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
1020
1021 static struct gbphy_driver uart_driver = {
1022         .name           = "uart",
1023         .probe          = gb_uart_probe,
1024         .remove         = gb_uart_remove,
1025         .id_table       = gb_uart_id_table,
1026 };
1027
1028 static int gb_uart_driver_init(void)
1029 {
1030         int ret;
1031
1032         ret = gb_tty_init();
1033         if (ret)
1034                 return ret;
1035
1036         ret = gb_gbphy_register(&uart_driver);
1037         if (ret) {
1038                 gb_tty_exit();
1039                 return ret;
1040         }
1041
1042         return 0;
1043 }
1044 module_init(gb_uart_driver_init);
1045
1046 static void gb_uart_driver_exit(void)
1047 {
1048         gb_gbphy_deregister(&uart_driver);
1049         gb_tty_exit();
1050 }
1051
1052 module_exit(gb_uart_driver_exit);
1053 MODULE_LICENSE("GPL v2");