drivers/staging/greybus/uart.c

   1 /*
   2  * UART driver for the Greybus "generic" UART module.
   3  *
   4  * Copyright 2014 Google Inc.
   5  * Copyright 2014 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  *
   9  * Heavily based on drivers/usb/class/cdc-acm.c and
  10  * drivers/usb/serial/usb-serial.c.
  11  */
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/module.h>
  17 #include <linux/sched.h>
  18 #include <linux/wait.h>
  19 #include <linux/slab.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/mutex.h>
  22 #include <linux/tty.h>
  23 #include <linux/serial.h>
  24 #include <linux/tty_driver.h>
  25 #include <linux/tty_flip.h>
  26 #include <linux/serial.h>
  27 #include <linux/idr.h>
  28 #include <linux/fs.h>
  29 #include <linux/kdev_t.h>
  30 #include <linux/kfifo.h>
  31 #include <linux/workqueue.h>
  32 #include <linux/completion.h>
  33
  34 #include "greybus.h"
  35 #include "gbphy.h"
  36
  37 #define GB_NUM_MINORS   16      /* 16 is is more than enough */
  38 #define GB_NAME         "ttyGB"
  39
  40 #define GB_UART_WRITE_FIFO_SIZE         PAGE_SIZE
  41 #define GB_UART_WRITE_ROOM_MARGIN       1       /* leave some space in fifo */
  42 #define GB_UART_FIRMWARE_CREDITS        4096
  43 #define GB_UART_CREDIT_WAIT_TIMEOUT_MSEC        10000
  44
  45 struct gb_tty_line_coding {
  46         __le32  rate;
  47         __u8    format;
  48         __u8    parity;
  49         __u8    data_bits;
  50         __u8    flow_control;
  51 };
  52
  53 struct gb_tty {
  54         struct gbphy_device *gbphy_dev;
  55         struct tty_port port;
  56         void *buffer;
  57         size_t buffer_payload_max;
  58         struct gb_connection *connection;
  59         u16 cport_id;
  60         unsigned int minor;
  61         unsigned char clocal;
  62         bool disconnected;
  63         spinlock_t read_lock;
  64         spinlock_t write_lock;
  65         struct async_icount iocount;
  66         struct async_icount oldcount;
  67         wait_queue_head_t wioctl;
  68         struct mutex mutex;
  69         u8 ctrlin;      /* input control lines */
  70         u8 ctrlout;     /* output control lines */
  71         struct gb_tty_line_coding line_coding;
  72         struct work_struct tx_work;
  73         struct kfifo write_fifo;
  74         bool close_pending;
  75         unsigned int credits;
  76         struct completion credits_complete;
  77 };
  78
  79 static struct tty_driver *gb_tty_driver;
  80 static DEFINE_IDR(tty_minors);
  81 static DEFINE_MUTEX(table_lock);
  82
  83 static int gb_uart_receive_data_handler(struct gb_operation *op)
  84 {
  85         struct gb_connection *connection = op->connection;
  86         struct gb_tty *gb_tty = gb_connection_get_data(connection);
  87         struct tty_port *port = &gb_tty->port;
  88         struct gb_message *request = op->request;
  89         struct gb_uart_recv_data_request *receive_data;
  90         u16 recv_data_size;
  91         int count;
  92         unsigned long tty_flags = TTY_NORMAL;
  93
  94         if (request->payload_size < sizeof(*receive_data)) {
  95                 dev_err(&gb_tty->gbphy_dev->dev,
  96                                 "short receive-data request received (%zu < %zu)\n",
  97                                 request->payload_size, sizeof(*receive_data));
  98                 return -EINVAL;
  99         }
 100
 101         receive_data = op->request->payload;
 102         recv_data_size = le16_to_cpu(receive_data->size);
 103
 104         if (recv_data_size != request->payload_size - sizeof(*receive_data)) {
 105                 dev_err(&gb_tty->gbphy_dev->dev,
 106                                 "malformed receive-data request received (%u != %zu)\n",
 107                                 recv_data_size,
 108                                 request->payload_size - sizeof(*receive_data));
 109                 return -EINVAL;
 110         }
 111
 112         if (!recv_data_size)
 113                 return -EINVAL;
 114
 115         if (receive_data->flags) {
 116                 if (receive_data->flags & GB_UART_RECV_FLAG_BREAK)
 117                         tty_flags = TTY_BREAK;
 118                 else if (receive_data->flags & GB_UART_RECV_FLAG_PARITY)
 119                         tty_flags = TTY_PARITY;
 120                 else if (receive_data->flags & GB_UART_RECV_FLAG_FRAMING)
 121                         tty_flags = TTY_FRAME;
 122
 123                 /* overrun is special, not associated with a char */
 124                 if (receive_data->flags & GB_UART_RECV_FLAG_OVERRUN)
 125                         tty_insert_flip_char(port, 0, TTY_OVERRUN);
 126         }
 127         count = tty_insert_flip_string_fixed_flag(port, receive_data->data,
 128                                                   tty_flags, recv_data_size);
 129         if (count != recv_data_size) {
 130                 dev_err(&gb_tty->gbphy_dev->dev,
 131                         "UART: RX 0x%08x bytes only wrote 0x%08x\n",
 132                         recv_data_size, count);
 133         }
 134         if (count)
 135                 tty_flip_buffer_push(port);
 136         return 0;
 137 }
 138
 139 static int gb_uart_serial_state_handler(struct gb_operation *op)
 140 {
 141         struct gb_connection *connection = op->connection;
 142         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 143         struct gb_message *request = op->request;
 144         struct gb_uart_serial_state_request *serial_state;
 145
 146         if (request->payload_size < sizeof(*serial_state)) {
 147                 dev_err(&gb_tty->gbphy_dev->dev,
 148                                 "short serial-state event received (%zu < %zu)\n",
 149                                 request->payload_size, sizeof(*serial_state));
 150                 return -EINVAL;
 151         }
 152
 153         serial_state = request->payload;
 154         gb_tty->ctrlin = serial_state->control;
 155
 156         return 0;
 157 }
 158
 159 static int gb_uart_receive_credits_handler(struct gb_operation *op)
 160 {
 161         struct gb_connection *connection = op->connection;
 162         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 163         struct gb_message *request = op->request;
 164         struct gb_uart_receive_credits_request *credit_request;
 165         unsigned long flags;
 166         unsigned int incoming_credits;
 167         int ret = 0;
 168
 169         if (request->payload_size < sizeof(*credit_request)) {
 170                 dev_err(&gb_tty->gbphy_dev->dev,
 171                                 "short receive_credits event received (%zu < %zu)\n",
 172                                 request->payload_size,
 173                                 sizeof(*credit_request));
 174                 return -EINVAL;
 175         }
 176
 177         credit_request = request->payload;
 178         incoming_credits = le16_to_cpu(credit_request->count);
 179
 180         spin_lock_irqsave(&gb_tty->write_lock, flags);
 181         gb_tty->credits += incoming_credits;
 182         if (gb_tty->credits > GB_UART_FIRMWARE_CREDITS) {
 183                 gb_tty->credits -= incoming_credits;
 184                 ret = -EINVAL;
 185         }
 186         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 187
 188         if (ret) {
 189                 dev_err(&gb_tty->gbphy_dev->dev,
 190                         "invalid number of incoming credits: %d\n",
 191                         incoming_credits);
 192                 return ret;
 193         }
 194
 195         if (!gb_tty->close_pending)
 196                 schedule_work(&gb_tty->tx_work);
 197
 198         /*
 199          * the port the tty layer may be waiting for credits
 200          */
 201         tty_port_tty_wakeup(&gb_tty->port);
 202
 203         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 204                 complete(&gb_tty->credits_complete);
 205
 206         return ret;
 207 }
 208
 209 static int gb_uart_request_handler(struct gb_operation *op)
 210 {
 211         struct gb_connection *connection = op->connection;
 212         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 213         int type = op->type;
 214         int ret;
 215
 216         switch (type) {
 217         case GB_UART_TYPE_RECEIVE_DATA:
 218                 ret = gb_uart_receive_data_handler(op);
 219                 break;
 220         case GB_UART_TYPE_SERIAL_STATE:
 221                 ret = gb_uart_serial_state_handler(op);
 222                 break;
 223         case GB_UART_TYPE_RECEIVE_CREDITS:
 224                 ret = gb_uart_receive_credits_handler(op);
 225                 break;
 226         default:
 227                 dev_err(&gb_tty->gbphy_dev->dev,
 228                         "unsupported unsolicited request: 0x%02x\n", type);
 229                 ret = -EINVAL;
 230         }
 231
 232         return ret;
 233 }
 234
 235 static void  gb_uart_tx_write_work(struct work_struct *work)
 236 {
 237         struct gb_uart_send_data_request *request;
 238         struct gb_tty *gb_tty;
 239         unsigned long flags;
 240         unsigned int send_size;
 241         int ret;
 242
 243         gb_tty = container_of(work, struct gb_tty, tx_work);
 244         request = gb_tty->buffer;
 245
 246         while (1) {
 247                 if (gb_tty->close_pending)
 248                         break;
 249
 250                 spin_lock_irqsave(&gb_tty->write_lock, flags);
 251                 send_size = gb_tty->buffer_payload_max;
 252                 if (send_size > gb_tty->credits)
 253                         send_size = gb_tty->credits;
 254
 255                 send_size = kfifo_out_peek(&gb_tty->write_fifo,
 256                                         &request->data[0],
 257                                         send_size);
 258                 if (!send_size) {
 259                         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 260                         break;
 261                 }
 262
 263                 gb_tty->credits -= send_size;
 264                 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 265
 266                 request->size = cpu_to_le16(send_size);
 267                 ret = gb_operation_sync(gb_tty->connection,
 268                                         GB_UART_TYPE_SEND_DATA,
 269                                         request, sizeof(*request) + send_size,
 270                                         NULL, 0);
 271                 if (ret) {
 272                         dev_err(&gb_tty->gbphy_dev->dev,
 273                                 "send data error: %d\n", ret);
 274                         spin_lock_irqsave(&gb_tty->write_lock, flags);
 275                         gb_tty->credits += send_size;
 276                         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 277                         if (!gb_tty->close_pending)
 278                                 schedule_work(work);
 279                         return;
 280                 }
 281
 282                 spin_lock_irqsave(&gb_tty->write_lock, flags);
 283                 ret = kfifo_out(&gb_tty->write_fifo, &request->data[0],
 284                                 send_size);
 285                 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 286
 287                 tty_port_tty_wakeup(&gb_tty->port);
 288         }
 289 }
 290
 291 static int send_line_coding(struct gb_tty *tty)
 292 {
 293         struct gb_uart_set_line_coding_request request;
 294
 295         memcpy(&request, &tty->line_coding,
 296                sizeof(tty->line_coding));
 297         return gb_operation_sync(tty->connection, GB_UART_TYPE_SET_LINE_CODING,
 298                                  &request, sizeof(request), NULL, 0);
 299 }
 300
 301 static int send_control(struct gb_tty *gb_tty, u8 control)
 302 {
 303         struct gb_uart_set_control_line_state_request request;
 304
 305         request.control = control;
 306         return gb_operation_sync(gb_tty->connection,
 307                                  GB_UART_TYPE_SET_CONTROL_LINE_STATE,
 308                                  &request, sizeof(request), NULL, 0);
 309 }
 310
 311 static int send_break(struct gb_tty *gb_tty, u8 state)
 312 {
 313         struct gb_uart_set_break_request request;
 314
 315         if ((state != 0) && (state != 1)) {
 316                 dev_err(&gb_tty->gbphy_dev->dev,
 317                         "invalid break state of %d\n", state);
 318                 return -EINVAL;
 319         }
 320
 321         request.state = state;
 322         return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_SEND_BREAK,
 323                                  &request, sizeof(request), NULL, 0);
 324 }
 325
 326 static int gb_uart_wait_for_all_credits(struct gb_tty *gb_tty)
 327 {
 328         int ret;
 329
 330         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 331                 return 0;
 332
 333         ret = wait_for_completion_timeout(&gb_tty->credits_complete,
 334                         msecs_to_jiffies(GB_UART_CREDIT_WAIT_TIMEOUT_MSEC));
 335         if (!ret) {
 336                 dev_err(&gb_tty->gbphy_dev->dev,
 337                         "time out waiting for credits\n");
 338                 return -ETIMEDOUT;
 339         }
 340
 341         return 0;
 342 }
 343
 344 static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
 345 {
 346         struct gb_uart_serial_flush_request request;
 347
 348         request.flags = flags;
 349         return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_FLUSH_FIFOS,
 350                                  &request, sizeof(request), NULL, 0);
 351 }
 352
 353 static struct gb_tty *get_gb_by_minor(unsigned minor)
 354 {
 355         struct gb_tty *gb_tty;
 356
 357         mutex_lock(&table_lock);
 358         gb_tty = idr_find(&tty_minors, minor);
 359         if (gb_tty) {
 360                 mutex_lock(&gb_tty->mutex);
 361                 if (gb_tty->disconnected) {
 362                         mutex_unlock(&gb_tty->mutex);
 363                         gb_tty = NULL;
 364                 } else {
 365                         tty_port_get(&gb_tty->port);
 366                         mutex_unlock(&gb_tty->mutex);
 367                 }
 368         }
 369         mutex_unlock(&table_lock);
 370         return gb_tty;
 371 }
 372
 373 static int alloc_minor(struct gb_tty *gb_tty)
 374 {
 375         int minor;
 376
 377         mutex_lock(&table_lock);
 378         minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
 379         mutex_unlock(&table_lock);
 380         if (minor >= 0)
 381                 gb_tty->minor = minor;
 382         return minor;
 383 }
 384
 385 static void release_minor(struct gb_tty *gb_tty)
 386 {
 387         int minor = gb_tty->minor;
 388
 389         gb_tty->minor = 0;      /* Maybe should use an invalid value instead */
 390         mutex_lock(&table_lock);
 391         idr_remove(&tty_minors, minor);
 392         mutex_unlock(&table_lock);
 393 }
 394
 395 static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty)
 396 {
 397         struct gb_tty *gb_tty;
 398         int retval;
 399
 400         gb_tty = get_gb_by_minor(tty->index);
 401         if (!gb_tty)
 402                 return -ENODEV;
 403
 404         retval = tty_standard_install(driver, tty);
 405         if (retval)
 406                 goto error;
 407
 408         tty->driver_data = gb_tty;
 409         return 0;
 410 error:
 411         tty_port_put(&gb_tty->port);
 412         return retval;
 413 }
 414
 415 static int gb_tty_open(struct tty_struct *tty, struct file *file)
 416 {
 417         struct gb_tty *gb_tty = tty->driver_data;
 418
 419         return tty_port_open(&gb_tty->port, tty, file);
 420 }
 421
 422 static void gb_tty_close(struct tty_struct *tty, struct file *file)
 423 {
 424         struct gb_tty *gb_tty = tty->driver_data;
 425
 426         tty_port_close(&gb_tty->port, tty, file);
 427 }
 428
 429 static void gb_tty_cleanup(struct tty_struct *tty)
 430 {
 431         struct gb_tty *gb_tty = tty->driver_data;
 432
 433         tty_port_put(&gb_tty->port);
 434 }
 435
 436 static void gb_tty_hangup(struct tty_struct *tty)
 437 {
 438         struct gb_tty *gb_tty = tty->driver_data;
 439
 440         tty_port_hangup(&gb_tty->port);
 441 }
 442
 443 static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
 444                         int count)
 445 {
 446         struct gb_tty *gb_tty = tty->driver_data;
 447
 448         count =  kfifo_in_spinlocked(&gb_tty->write_fifo, buf, count,
 449                                         &gb_tty->write_lock);
 450         if (count && !gb_tty->close_pending)
 451                 schedule_work(&gb_tty->tx_work);
 452
 453         return count;
 454 }
 455
 456 static int gb_tty_write_room(struct tty_struct *tty)
 457 {
 458         struct gb_tty *gb_tty = tty->driver_data;
 459         unsigned long flags;
 460         int room;
 461
 462         spin_lock_irqsave(&gb_tty->write_lock, flags);
 463         room = kfifo_avail(&gb_tty->write_fifo);
 464         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 465
 466         room -= GB_UART_WRITE_ROOM_MARGIN;
 467         if (room < 0)
 468                 return 0;
 469
 470         return room;
 471 }
 472
 473 static int gb_tty_chars_in_buffer(struct tty_struct *tty)
 474 {
 475         struct gb_tty *gb_tty = tty->driver_data;
 476         unsigned long flags;
 477         int chars;
 478
 479         spin_lock_irqsave(&gb_tty->write_lock, flags);
 480         chars = kfifo_len(&gb_tty->write_fifo);
 481         if (gb_tty->credits < GB_UART_FIRMWARE_CREDITS)
 482                 chars += GB_UART_FIRMWARE_CREDITS - gb_tty->credits;
 483         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 484
 485         return chars;
 486 }
 487
 488 static int gb_tty_break_ctl(struct tty_struct *tty, int state)
 489 {
 490         struct gb_tty *gb_tty = tty->driver_data;
 491
 492         return send_break(gb_tty, state ? 1 : 0);
 493 }
 494
 495 static void gb_tty_set_termios(struct tty_struct *tty,
 496                                struct ktermios *termios_old)
 497 {
 498         struct gb_tty *gb_tty = tty->driver_data;
 499         struct ktermios *termios = &tty->termios;
 500         struct gb_tty_line_coding newline;
 501         u8 newctrl = gb_tty->ctrlout;
 502
 503         newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
 504         newline.format = termios->c_cflag & CSTOPB ?
 505                                 GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
 506         newline.parity = termios->c_cflag & PARENB ?
 507                                 (termios->c_cflag & PARODD ? 1 : 2) +
 508                                 (termios->c_cflag & CMSPAR ? 2 : 0) : 0;
 509
 510         switch (termios->c_cflag & CSIZE) {
 511         case CS5:
 512                 newline.data_bits = 5;
 513                 break;
 514         case CS6:
 515                 newline.data_bits = 6;
 516                 break;
 517         case CS7:
 518                 newline.data_bits = 7;
 519                 break;
 520         case CS8:
 521         default:
 522                 newline.data_bits = 8;
 523                 break;
 524         }
 525
 526         /* FIXME: needs to clear unsupported bits in the termios */
 527         gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
 528
 529         if (C_BAUD(tty) == B0) {
 530                 newline.rate = gb_tty->line_coding.rate;
 531                 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 532         } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
 533                 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 534         }
 535
 536         if (newctrl != gb_tty->ctrlout) {
 537                 gb_tty->ctrlout = newctrl;
 538                 send_control(gb_tty, newctrl);
 539         }
 540
 541         if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
 542                 newline.flow_control |= GB_SERIAL_AUTO_RTSCTS_EN;
 543         else
 544                 newline.flow_control &= ~GB_SERIAL_AUTO_RTSCTS_EN;
 545
 546         if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
 547                 memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
 548                 send_line_coding(gb_tty);
 549         }
 550 }
 551
 552 static int gb_tty_tiocmget(struct tty_struct *tty)
 553 {
 554         struct gb_tty *gb_tty = tty->driver_data;
 555
 556         return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
 557                (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
 558                (gb_tty->ctrlin  & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
 559                (gb_tty->ctrlin  & GB_UART_CTRL_RI  ? TIOCM_RI  : 0) |
 560                (gb_tty->ctrlin  & GB_UART_CTRL_DCD ? TIOCM_CD  : 0) |
 561                TIOCM_CTS;
 562 }
 563
 564 static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
 565                            unsigned int clear)
 566 {
 567         struct gb_tty *gb_tty = tty->driver_data;
 568         u8 newctrl = gb_tty->ctrlout;
 569
 570         set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
 571               (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
 572         clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
 573                 (clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
 574
 575         newctrl = (newctrl & ~clear) | set;
 576         if (gb_tty->ctrlout == newctrl)
 577                 return 0;
 578
 579         gb_tty->ctrlout = newctrl;
 580         return send_control(gb_tty, newctrl);
 581 }
 582
 583 static void gb_tty_throttle(struct tty_struct *tty)
 584 {
 585         struct gb_tty *gb_tty = tty->driver_data;
 586         unsigned char stop_char;
 587         int retval;
 588
 589         if (I_IXOFF(tty)) {
 590                 stop_char = STOP_CHAR(tty);
 591                 retval = gb_tty_write(tty, &stop_char, 1);
 592                 if (retval <= 0)
 593                         return;
 594         }
 595
 596         if (tty->termios.c_cflag & CRTSCTS) {
 597                 gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
 598                 retval = send_control(gb_tty, gb_tty->ctrlout);
 599         }
 600 }
 601
 602 static void gb_tty_unthrottle(struct tty_struct *tty)
 603 {
 604         struct gb_tty *gb_tty = tty->driver_data;
 605         unsigned char start_char;
 606         int retval;
 607
 608         if (I_IXOFF(tty)) {
 609                 start_char = START_CHAR(tty);
 610                 retval = gb_tty_write(tty, &start_char, 1);
 611                 if (retval <= 0)
 612                         return;
 613         }
 614
 615         if (tty->termios.c_cflag & CRTSCTS) {
 616                 gb_tty->ctrlout |= GB_UART_CTRL_RTS;
 617                 retval = send_control(gb_tty, gb_tty->ctrlout);
 618         }
 619 }
 620
 621 static int get_serial_info(struct gb_tty *gb_tty,
 622                            struct serial_struct __user *info)
 623 {
 624         struct serial_struct tmp;
 625
 626         if (!info)
 627                 return -EINVAL;
 628
 629         memset(&tmp, 0, sizeof(tmp));
 630         tmp.flags = ASYNC_LOW_LATENCY | ASYNC_SKIP_TEST;
 631         tmp.type = PORT_16550A;
 632         tmp.line = gb_tty->minor;
 633         tmp.xmit_fifo_size = 16;
 634         tmp.baud_base = 9600;
 635         tmp.close_delay = gb_tty->port.close_delay / 10;
 636         tmp.closing_wait = gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 637                                 ASYNC_CLOSING_WAIT_NONE : gb_tty->port.closing_wait / 10;
 638
 639         if (copy_to_user(info, &tmp, sizeof(tmp)))
 640                 return -EFAULT;
 641         return 0;
 642 }
 643
 644 static int set_serial_info(struct gb_tty *gb_tty,
 645                            struct serial_struct __user *newinfo)
 646 {
 647         struct serial_struct new_serial;
 648         unsigned int closing_wait;
 649         unsigned int close_delay;
 650         int retval = 0;
 651
 652         if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
 653                 return -EFAULT;
 654
 655         close_delay = new_serial.close_delay * 10;
 656         closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 657                         ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
 658
 659         mutex_lock(&gb_tty->port.mutex);
 660         if (!capable(CAP_SYS_ADMIN)) {
 661                 if ((close_delay != gb_tty->port.close_delay) ||
 662                     (closing_wait != gb_tty->port.closing_wait))
 663                         retval = -EPERM;
 664                 else
 665                         retval = -EOPNOTSUPP;
 666         } else {
 667                 gb_tty->port.close_delay = close_delay;
 668                 gb_tty->port.closing_wait = closing_wait;
 669         }
 670         mutex_unlock(&gb_tty->port.mutex);
 671         return retval;
 672 }
 673
 674 static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
 675 {
 676         int retval = 0;
 677         unsigned long flags;
 678         DECLARE_WAITQUEUE(wait, current);
 679         struct async_icount old;
 680         struct async_icount new;
 681
 682         if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
 683                 return -EINVAL;
 684
 685         do {
 686                 spin_lock_irqsave(&gb_tty->read_lock, flags);
 687                 old = gb_tty->oldcount;
 688                 new = gb_tty->iocount;
 689                 gb_tty->oldcount = new;
 690                 spin_unlock_irqrestore(&gb_tty->read_lock, flags);
 691
 692                 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
 693                         break;
 694                 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
 695                         break;
 696                 if ((arg & TIOCM_RI) && (old.rng != new.rng))
 697                         break;
 698
 699                 add_wait_queue(&gb_tty->wioctl, &wait);
 700                 set_current_state(TASK_INTERRUPTIBLE);
 701                 schedule();
 702                 remove_wait_queue(&gb_tty->wioctl, &wait);
 703                 if (gb_tty->disconnected) {
 704                         if (arg & TIOCM_CD)
 705                                 break;
 706                         retval = -ENODEV;
 707                 } else if (signal_pending(current)) {
 708                         retval = -ERESTARTSYS;
 709                 }
 710         } while (!retval);
 711
 712         return retval;
 713 }
 714
 715 static int get_serial_usage(struct gb_tty *gb_tty,
 716                             struct serial_icounter_struct __user *count)
 717 {
 718         struct serial_icounter_struct icount;
 719         int retval = 0;
 720
 721         memset(&icount, 0, sizeof(icount));
 722         icount.dsr = gb_tty->iocount.dsr;
 723         icount.rng = gb_tty->iocount.rng;
 724         icount.dcd = gb_tty->iocount.dcd;
 725         icount.frame = gb_tty->iocount.frame;
 726         icount.overrun = gb_tty->iocount.overrun;
 727         icount.parity = gb_tty->iocount.parity;
 728         icount.brk = gb_tty->iocount.brk;
 729
 730         if (copy_to_user(count, &icount, sizeof(icount)) > 0)
 731                 retval = -EFAULT;
 732
 733         return retval;
 734 }
 735
 736 static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
 737                         unsigned long arg)
 738 {
 739         struct gb_tty *gb_tty = tty->driver_data;
 740
 741         switch (cmd) {
 742         case TIOCGSERIAL:
 743                 return get_serial_info(gb_tty,
 744                                        (struct serial_struct __user *)arg);
 745         case TIOCSSERIAL:
 746                 return set_serial_info(gb_tty,
 747                                        (struct serial_struct __user *)arg);
 748         case TIOCMIWAIT:
 749                 return wait_serial_change(gb_tty, arg);
 750         case TIOCGICOUNT:
 751                 return get_serial_usage(gb_tty,
 752                                         (struct serial_icounter_struct __user *)arg);
 753         }
 754
 755         return -ENOIOCTLCMD;
 756 }
 757
 758 static void gb_tty_dtr_rts(struct tty_port *port, int on)
 759 {
 760         struct gb_tty *gb_tty;
 761         u8 newctrl;
 762
 763         gb_tty = container_of(port, struct gb_tty, port);
 764         newctrl = gb_tty->ctrlout;
 765
 766         if (on)
 767                 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 768         else
 769                 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 770
 771         gb_tty->ctrlout = newctrl;
 772         send_control(gb_tty, newctrl);
 773 }
 774
 775 static void gb_tty_port_shutdown(struct tty_port *port)
 776 {
 777         struct gb_tty *gb_tty;
 778         unsigned long flags;
 779         int ret;
 780
 781         gb_tty = container_of(port, struct gb_tty, port);
 782
 783         gb_tty->close_pending = true;
 784
 785         cancel_work_sync(&gb_tty->tx_work);
 786
 787         spin_lock_irqsave(&gb_tty->write_lock, flags);
 788         kfifo_reset_out(&gb_tty->write_fifo);
 789         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 790
 791         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 792                 goto out;
 793
 794         ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
 795         if (ret) {
 796                 dev_err(&gb_tty->gbphy_dev->dev,
 797                         "error flushing transmitter: %d\n", ret);
 798         }
 799
 800         gb_uart_wait_for_all_credits(gb_tty);
 801
 802 out:
 803         gb_tty->close_pending = false;
 804 }
 805
 806 static const struct tty_operations gb_ops = {
 807         .install =              gb_tty_install,
 808         .open =                 gb_tty_open,
 809         .close =                gb_tty_close,
 810         .cleanup =              gb_tty_cleanup,
 811         .hangup =               gb_tty_hangup,
 812         .write =                gb_tty_write,
 813         .write_room =           gb_tty_write_room,
 814         .ioctl =                gb_tty_ioctl,
 815         .throttle =             gb_tty_throttle,
 816         .unthrottle =           gb_tty_unthrottle,
 817         .chars_in_buffer =      gb_tty_chars_in_buffer,
 818         .break_ctl =            gb_tty_break_ctl,
 819         .set_termios =          gb_tty_set_termios,
 820         .tiocmget =             gb_tty_tiocmget,
 821         .tiocmset =             gb_tty_tiocmset,
 822 };
 823
 824 static struct tty_port_operations gb_port_ops = {
 825         .dtr_rts =              gb_tty_dtr_rts,
 826         .shutdown =             gb_tty_port_shutdown,
 827 };
 828
 829 static int gb_uart_probe(struct gbphy_device *gbphy_dev,
 830                          const struct gbphy_device_id *id)
 831 {
 832         struct gb_connection *connection;
 833         size_t max_payload;
 834         struct gb_tty *gb_tty;
 835         struct device *tty_dev;
 836         int retval;
 837         int minor;
 838
 839         gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
 840         if (!gb_tty)
 841                 return -ENOMEM;
 842
 843         connection = gb_connection_create(gbphy_dev->bundle,
 844                                           le16_to_cpu(gbphy_dev->cport_desc->id),
 845                                           gb_uart_request_handler);
 846         if (IS_ERR(connection)) {
 847                 retval = PTR_ERR(connection);
 848                 goto exit_tty_free;
 849         }
 850
 851         max_payload = gb_operation_get_payload_size_max(connection);
 852         if (max_payload < sizeof(struct gb_uart_send_data_request)) {
 853                 retval = -EINVAL;
 854                 goto exit_connection_destroy;
 855         }
 856
 857         gb_tty->buffer_payload_max = max_payload -
 858                         sizeof(struct gb_uart_send_data_request);
 859
 860         gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
 861         if (!gb_tty->buffer) {
 862                 retval = -ENOMEM;
 863                 goto exit_connection_destroy;
 864         }
 865
 866         INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
 867
 868         retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
 869                                 GFP_KERNEL);
 870         if (retval)
 871                 goto exit_buf_free;
 872
 873         gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
 874         init_completion(&gb_tty->credits_complete);
 875
 876         minor = alloc_minor(gb_tty);
 877         if (minor < 0) {
 878                 if (minor == -ENOSPC) {
 879                         dev_err(&connection->bundle->dev,
 880                                 "no more free minor numbers\n");
 881                         retval = -ENODEV;
 882                 } else {
 883                         retval = minor;
 884                 }
 885                 goto exit_kfifo_free;
 886         }
 887
 888         gb_tty->minor = minor;
 889         spin_lock_init(&gb_tty->write_lock);
 890         spin_lock_init(&gb_tty->read_lock);
 891         init_waitqueue_head(&gb_tty->wioctl);
 892         mutex_init(&gb_tty->mutex);
 893
 894         tty_port_init(&gb_tty->port);
 895         gb_tty->port.ops = &gb_port_ops;
 896
 897         gb_tty->connection = connection;
 898         gb_tty->gbphy_dev = gbphy_dev;
 899         gb_connection_set_data(connection, gb_tty);
 900         gb_gbphy_set_data(gbphy_dev, gb_tty);
 901
 902         retval = gb_connection_enable_tx(connection);
 903         if (retval)
 904                 goto exit_release_minor;
 905
 906         send_control(gb_tty, gb_tty->ctrlout);
 907
 908         /* initialize the uart to be 9600n81 */
 909         gb_tty->line_coding.rate = cpu_to_le32(9600);
 910         gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
 911         gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
 912         gb_tty->line_coding.data_bits = 8;
 913         send_line_coding(gb_tty);
 914
 915         retval = gb_connection_enable(connection);
 916         if (retval)
 917                 goto exit_connection_disable;
 918
 919         tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
 920                                            &gbphy_dev->dev);
 921         if (IS_ERR(tty_dev)) {
 922                 retval = PTR_ERR(tty_dev);
 923                 goto exit_connection_disable;
 924         }
 925
 926         return 0;
 927
 928 exit_connection_disable:
 929         gb_connection_disable(connection);
 930 exit_release_minor:
 931         release_minor(gb_tty);
 932 exit_kfifo_free:
 933         kfifo_free(&gb_tty->write_fifo);
 934 exit_buf_free:
 935         kfree(gb_tty->buffer);
 936 exit_connection_destroy:
 937         gb_connection_destroy(connection);
 938 exit_tty_free:
 939         kfree(gb_tty);
 940
 941         return retval;
 942 }
 943
 944 static void gb_uart_remove(struct gbphy_device *gbphy_dev)
 945 {
 946         struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
 947         struct gb_connection *connection = gb_tty->connection;
 948         struct tty_struct *tty;
 949
 950         mutex_lock(&gb_tty->mutex);
 951         gb_tty->disconnected = true;
 952
 953         wake_up_all(&gb_tty->wioctl);
 954         mutex_unlock(&gb_tty->mutex);
 955
 956         tty = tty_port_tty_get(&gb_tty->port);
 957         if (tty) {
 958                 tty_vhangup(tty);
 959                 tty_kref_put(tty);
 960         }
 961
 962         gb_connection_disable_rx(connection);
 963         tty_unregister_device(gb_tty_driver, gb_tty->minor);
 964
 965         /* FIXME - free transmit / receive buffers */
 966
 967         gb_connection_disable(connection);
 968         tty_port_destroy(&gb_tty->port);
 969         gb_connection_destroy(connection);
 970         release_minor(gb_tty);
 971         kfifo_free(&gb_tty->write_fifo);
 972         kfree(gb_tty->buffer);
 973         kfree(gb_tty);
 974 }
 975
 976 static int gb_tty_init(void)
 977 {
 978         int retval = 0;
 979
 980         gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
 981         if (IS_ERR(gb_tty_driver)) {
 982                 pr_err("Can not allocate tty driver\n");
 983                 retval = -ENOMEM;
 984                 goto fail_unregister_dev;
 985         }
 986
 987         gb_tty_driver->driver_name = "gb";
 988         gb_tty_driver->name = GB_NAME;
 989         gb_tty_driver->major = 0;
 990         gb_tty_driver->minor_start = 0;
 991         gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
 992         gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
 993         gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 994         gb_tty_driver->init_termios = tty_std_termios;
 995         gb_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 996         tty_set_operations(gb_tty_driver, &gb_ops);
 997
 998         retval = tty_register_driver(gb_tty_driver);
 999         if (retval) {
1000                 pr_err("Can not register tty driver: %d\n", retval);
1001                 goto fail_put_gb_tty;
1002         }
1003
1004         return 0;
1005
1006 fail_put_gb_tty:
1007         put_tty_driver(gb_tty_driver);
1008 fail_unregister_dev:
1009         return retval;
1010 }
1011
1012 static void gb_tty_exit(void)
1013 {
1014         tty_unregister_driver(gb_tty_driver);
1015         put_tty_driver(gb_tty_driver);
1016         idr_destroy(&tty_minors);
1017 }
1018
1019 static const struct gbphy_device_id gb_uart_id_table[] = {
1020         { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
1021         { },
1022 };
1023 MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
1024
1025 static struct gbphy_driver uart_driver = {
1026         .name           = "uart",
1027         .probe          = gb_uart_probe,
1028         .remove         = gb_uart_remove,
1029         .id_table       = gb_uart_id_table,
1030 };
1031
1032 static int gb_uart_driver_init(void)
1033 {
1034         int ret;
1035
1036         ret = gb_tty_init();
1037         if (ret)
1038                 return ret;
1039
1040         ret = gb_gbphy_register(&uart_driver);
1041         if (ret) {
1042                 gb_tty_exit();
1043                 return ret;
1044         }
1045
1046         return 0;
1047 }
1048 module_init(gb_uart_driver_init);
1049
1050 static void gb_uart_driver_exit(void)
1051 {
1052         gb_gbphy_deregister(&uart_driver);
1053         gb_tty_exit();
1054 }
1055
1056 module_exit(gb_uart_driver_exit);
1057 MODULE_LICENSE("GPL v2");