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/signal.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/idr.h>
  27 #include <linux/fs.h>
  28 #include <linux/kdev_t.h>
  29 #include <linux/kfifo.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/completion.h>
  32
  33 #include "greybus.h"
  34 #include "gbphy.h"
  35
  36 #define GB_NUM_MINORS   16      /* 16 is more than enough */
  37 #define GB_NAME         "ttyGB"
  38
  39 #define GB_UART_WRITE_FIFO_SIZE         PAGE_SIZE
  40 #define GB_UART_WRITE_ROOM_MARGIN       1       /* leave some space in fifo */
  41 #define GB_UART_FIRMWARE_CREDITS        4096
  42 #define GB_UART_CREDIT_WAIT_TIMEOUT_MSEC        10000
  43
  44 struct gb_tty_line_coding {
  45         __le32  rate;
  46         __u8    format;
  47         __u8    parity;
  48         __u8    data_bits;
  49         __u8    flow_control;
  50 };
  51
  52 struct gb_tty {
  53         struct gbphy_device *gbphy_dev;
  54         struct tty_port port;
  55         void *buffer;
  56         size_t buffer_payload_max;
  57         struct gb_connection *connection;
  58         u16 cport_id;
  59         unsigned int minor;
  60         unsigned char clocal;
  61         bool disconnected;
  62         spinlock_t read_lock;
  63         spinlock_t write_lock;
  64         struct async_icount iocount;
  65         struct async_icount oldcount;
  66         wait_queue_head_t wioctl;
  67         struct mutex mutex;
  68         u8 ctrlin;      /* input control lines */
  69         u8 ctrlout;     /* output control lines */
  70         struct gb_tty_line_coding line_coding;
  71         struct work_struct tx_work;
  72         struct kfifo write_fifo;
  73         bool close_pending;
  74         unsigned int credits;
  75         struct completion credits_complete;
  76 };
  77
  78 static struct tty_driver *gb_tty_driver;
  79 static DEFINE_IDR(tty_minors);
  80 static DEFINE_MUTEX(table_lock);
  81
  82 static int gb_uart_receive_data_handler(struct gb_operation *op)
  83 {
  84         struct gb_connection *connection = op->connection;
  85         struct gb_tty *gb_tty = gb_connection_get_data(connection);
  86         struct tty_port *port = &gb_tty->port;
  87         struct gb_message *request = op->request;
  88         struct gb_uart_recv_data_request *receive_data;
  89         u16 recv_data_size;
  90         int count;
  91         unsigned long tty_flags = TTY_NORMAL;
  92
  93         if (request->payload_size < sizeof(*receive_data)) {
  94                 dev_err(&gb_tty->gbphy_dev->dev,
  95                         "short receive-data request received (%zu < %zu)\n",
  96                         request->payload_size, sizeof(*receive_data));
  97                 return -EINVAL;
  98         }
  99
 100         receive_data = op->request->payload;
 101         recv_data_size = le16_to_cpu(receive_data->size);
 102
 103         if (recv_data_size != request->payload_size - sizeof(*receive_data)) {
 104                 dev_err(&gb_tty->gbphy_dev->dev,
 105                         "malformed receive-data request received (%u != %zu)\n",
 106                         recv_data_size,
 107                         request->payload_size - sizeof(*receive_data));
 108                 return -EINVAL;
 109         }
 110
 111         if (!recv_data_size)
 112                 return -EINVAL;
 113
 114         if (receive_data->flags) {
 115                 if (receive_data->flags & GB_UART_RECV_FLAG_BREAK)
 116                         tty_flags = TTY_BREAK;
 117                 else if (receive_data->flags & GB_UART_RECV_FLAG_PARITY)
 118                         tty_flags = TTY_PARITY;
 119                 else if (receive_data->flags & GB_UART_RECV_FLAG_FRAMING)
 120                         tty_flags = TTY_FRAME;
 121
 122                 /* overrun is special, not associated with a char */
 123                 if (receive_data->flags & GB_UART_RECV_FLAG_OVERRUN)
 124                         tty_insert_flip_char(port, 0, TTY_OVERRUN);
 125         }
 126         count = tty_insert_flip_string_fixed_flag(port, receive_data->data,
 127                                                   tty_flags, recv_data_size);
 128         if (count != recv_data_size) {
 129                 dev_err(&gb_tty->gbphy_dev->dev,
 130                         "UART: RX 0x%08x bytes only wrote 0x%08x\n",
 131                         recv_data_size, count);
 132         }
 133         if (count)
 134                 tty_flip_buffer_push(port);
 135         return 0;
 136 }
 137
 138 static int gb_uart_serial_state_handler(struct gb_operation *op)
 139 {
 140         struct gb_connection *connection = op->connection;
 141         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 142         struct gb_message *request = op->request;
 143         struct gb_uart_serial_state_request *serial_state;
 144
 145         if (request->payload_size < sizeof(*serial_state)) {
 146                 dev_err(&gb_tty->gbphy_dev->dev,
 147                         "short serial-state event received (%zu < %zu)\n",
 148                         request->payload_size, sizeof(*serial_state));
 149                 return -EINVAL;
 150         }
 151
 152         serial_state = request->payload;
 153         gb_tty->ctrlin = serial_state->control;
 154
 155         return 0;
 156 }
 157
 158 static int gb_uart_receive_credits_handler(struct gb_operation *op)
 159 {
 160         struct gb_connection *connection = op->connection;
 161         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 162         struct gb_message *request = op->request;
 163         struct gb_uart_receive_credits_request *credit_request;
 164         unsigned long flags;
 165         unsigned int incoming_credits;
 166         int ret = 0;
 167
 168         if (request->payload_size < sizeof(*credit_request)) {
 169                 dev_err(&gb_tty->gbphy_dev->dev,
 170                         "short receive_credits event received (%zu < %zu)\n",
 171                         request->payload_size,
 172                         sizeof(*credit_request));
 173                 return -EINVAL;
 174         }
 175
 176         credit_request = request->payload;
 177         incoming_credits = le16_to_cpu(credit_request->count);
 178
 179         spin_lock_irqsave(&gb_tty->write_lock, flags);
 180         gb_tty->credits += incoming_credits;
 181         if (gb_tty->credits > GB_UART_FIRMWARE_CREDITS) {
 182                 gb_tty->credits -= incoming_credits;
 183                 ret = -EINVAL;
 184         }
 185         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 186
 187         if (ret) {
 188                 dev_err(&gb_tty->gbphy_dev->dev,
 189                         "invalid number of incoming credits: %d\n",
 190                         incoming_credits);
 191                 return ret;
 192         }
 193
 194         if (!gb_tty->close_pending)
 195                 schedule_work(&gb_tty->tx_work);
 196
 197         /*
 198          * the port the tty layer may be waiting for credits
 199          */
 200         tty_port_tty_wakeup(&gb_tty->port);
 201
 202         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 203                 complete(&gb_tty->credits_complete);
 204
 205         return ret;
 206 }
 207
 208 static int gb_uart_request_handler(struct gb_operation *op)
 209 {
 210         struct gb_connection *connection = op->connection;
 211         struct gb_tty *gb_tty = gb_connection_get_data(connection);
 212         int type = op->type;
 213         int ret;
 214
 215         switch (type) {
 216         case GB_UART_TYPE_RECEIVE_DATA:
 217                 ret = gb_uart_receive_data_handler(op);
 218                 break;
 219         case GB_UART_TYPE_SERIAL_STATE:
 220                 ret = gb_uart_serial_state_handler(op);
 221                 break;
 222         case GB_UART_TYPE_RECEIVE_CREDITS:
 223                 ret = gb_uart_receive_credits_handler(op);
 224                 break;
 225         default:
 226                 dev_err(&gb_tty->gbphy_dev->dev,
 227                         "unsupported unsolicited request: 0x%02x\n", type);
 228                 ret = -EINVAL;
 229         }
 230
 231         return ret;
 232 }
 233
 234 static void  gb_uart_tx_write_work(struct work_struct *work)
 235 {
 236         struct gb_uart_send_data_request *request;
 237         struct gb_tty *gb_tty;
 238         unsigned long flags;
 239         unsigned int send_size;
 240         int ret;
 241
 242         gb_tty = container_of(work, struct gb_tty, tx_work);
 243         request = gb_tty->buffer;
 244
 245         while (1) {
 246                 if (gb_tty->close_pending)
 247                         break;
 248
 249                 spin_lock_irqsave(&gb_tty->write_lock, flags);
 250                 send_size = gb_tty->buffer_payload_max;
 251                 if (send_size > gb_tty->credits)
 252                         send_size = gb_tty->credits;
 253
 254                 send_size = kfifo_out_peek(&gb_tty->write_fifo,
 255                                            &request->data[0],
 256                                            send_size);
 257                 if (!send_size) {
 258                         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 259                         break;
 260                 }
 261
 262                 gb_tty->credits -= send_size;
 263                 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 264
 265                 request->size = cpu_to_le16(send_size);
 266                 ret = gb_operation_sync(gb_tty->connection,
 267                                         GB_UART_TYPE_SEND_DATA,
 268                                         request, sizeof(*request) + send_size,
 269                                         NULL, 0);
 270                 if (ret) {
 271                         dev_err(&gb_tty->gbphy_dev->dev,
 272                                 "send data error: %d\n", ret);
 273                         spin_lock_irqsave(&gb_tty->write_lock, flags);
 274                         gb_tty->credits += send_size;
 275                         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 276                         if (!gb_tty->close_pending)
 277                                 schedule_work(work);
 278                         return;
 279                 }
 280
 281                 spin_lock_irqsave(&gb_tty->write_lock, flags);
 282                 ret = kfifo_out(&gb_tty->write_fifo, &request->data[0],
 283                                 send_size);
 284                 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 285
 286                 tty_port_tty_wakeup(&gb_tty->port);
 287         }
 288 }
 289
 290 static int send_line_coding(struct gb_tty *tty)
 291 {
 292         struct gb_uart_set_line_coding_request request;
 293
 294         memcpy(&request, &tty->line_coding,
 295                sizeof(tty->line_coding));
 296         return gb_operation_sync(tty->connection, GB_UART_TYPE_SET_LINE_CODING,
 297                                  &request, sizeof(request), NULL, 0);
 298 }
 299
 300 static int send_control(struct gb_tty *gb_tty, u8 control)
 301 {
 302         struct gb_uart_set_control_line_state_request request;
 303
 304         request.control = control;
 305         return gb_operation_sync(gb_tty->connection,
 306                                  GB_UART_TYPE_SET_CONTROL_LINE_STATE,
 307                                  &request, sizeof(request), NULL, 0);
 308 }
 309
 310 static int send_break(struct gb_tty *gb_tty, u8 state)
 311 {
 312         struct gb_uart_set_break_request request;
 313
 314         if ((state != 0) && (state != 1)) {
 315                 dev_err(&gb_tty->gbphy_dev->dev,
 316                         "invalid break state of %d\n", state);
 317                 return -EINVAL;
 318         }
 319
 320         request.state = state;
 321         return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_SEND_BREAK,
 322                                  &request, sizeof(request), NULL, 0);
 323 }
 324
 325 static int gb_uart_wait_for_all_credits(struct gb_tty *gb_tty)
 326 {
 327         int ret;
 328
 329         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 330                 return 0;
 331
 332         ret = wait_for_completion_timeout(&gb_tty->credits_complete,
 333                         msecs_to_jiffies(GB_UART_CREDIT_WAIT_TIMEOUT_MSEC));
 334         if (!ret) {
 335                 dev_err(&gb_tty->gbphy_dev->dev,
 336                         "time out waiting for credits\n");
 337                 return -ETIMEDOUT;
 338         }
 339
 340         return 0;
 341 }
 342
 343 static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
 344 {
 345         struct gb_uart_serial_flush_request request;
 346
 347         request.flags = flags;
 348         return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_FLUSH_FIFOS,
 349                                  &request, sizeof(request), NULL, 0);
 350 }
 351
 352 static struct gb_tty *get_gb_by_minor(unsigned int minor)
 353 {
 354         struct gb_tty *gb_tty;
 355
 356         mutex_lock(&table_lock);
 357         gb_tty = idr_find(&tty_minors, minor);
 358         if (gb_tty) {
 359                 mutex_lock(&gb_tty->mutex);
 360                 if (gb_tty->disconnected) {
 361                         mutex_unlock(&gb_tty->mutex);
 362                         gb_tty = NULL;
 363                 } else {
 364                         tty_port_get(&gb_tty->port);
 365                         mutex_unlock(&gb_tty->mutex);
 366                 }
 367         }
 368         mutex_unlock(&table_lock);
 369         return gb_tty;
 370 }
 371
 372 static int alloc_minor(struct gb_tty *gb_tty)
 373 {
 374         int minor;
 375
 376         mutex_lock(&table_lock);
 377         minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
 378         mutex_unlock(&table_lock);
 379         if (minor >= 0)
 380                 gb_tty->minor = minor;
 381         return minor;
 382 }
 383
 384 static void release_minor(struct gb_tty *gb_tty)
 385 {
 386         int minor = gb_tty->minor;
 387
 388         gb_tty->minor = 0;      /* Maybe should use an invalid value instead */
 389         mutex_lock(&table_lock);
 390         idr_remove(&tty_minors, minor);
 391         mutex_unlock(&table_lock);
 392 }
 393
 394 static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty)
 395 {
 396         struct gb_tty *gb_tty;
 397         int retval;
 398
 399         gb_tty = get_gb_by_minor(tty->index);
 400         if (!gb_tty)
 401                 return -ENODEV;
 402
 403         retval = tty_standard_install(driver, tty);
 404         if (retval)
 405                 goto error;
 406
 407         tty->driver_data = gb_tty;
 408         return 0;
 409 error:
 410         tty_port_put(&gb_tty->port);
 411         return retval;
 412 }
 413
 414 static int gb_tty_open(struct tty_struct *tty, struct file *file)
 415 {
 416         struct gb_tty *gb_tty = tty->driver_data;
 417
 418         return tty_port_open(&gb_tty->port, tty, file);
 419 }
 420
 421 static void gb_tty_close(struct tty_struct *tty, struct file *file)
 422 {
 423         struct gb_tty *gb_tty = tty->driver_data;
 424
 425         tty_port_close(&gb_tty->port, tty, file);
 426 }
 427
 428 static void gb_tty_cleanup(struct tty_struct *tty)
 429 {
 430         struct gb_tty *gb_tty = tty->driver_data;
 431
 432         tty_port_put(&gb_tty->port);
 433 }
 434
 435 static void gb_tty_hangup(struct tty_struct *tty)
 436 {
 437         struct gb_tty *gb_tty = tty->driver_data;
 438
 439         tty_port_hangup(&gb_tty->port);
 440 }
 441
 442 static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
 443                         int count)
 444 {
 445         struct gb_tty *gb_tty = tty->driver_data;
 446
 447         count =  kfifo_in_spinlocked(&gb_tty->write_fifo, buf, count,
 448                                      &gb_tty->write_lock);
 449         if (count && !gb_tty->close_pending)
 450                 schedule_work(&gb_tty->tx_work);
 451
 452         return count;
 453 }
 454
 455 static int gb_tty_write_room(struct tty_struct *tty)
 456 {
 457         struct gb_tty *gb_tty = tty->driver_data;
 458         unsigned long flags;
 459         int room;
 460
 461         spin_lock_irqsave(&gb_tty->write_lock, flags);
 462         room = kfifo_avail(&gb_tty->write_fifo);
 463         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 464
 465         room -= GB_UART_WRITE_ROOM_MARGIN;
 466         if (room < 0)
 467                 return 0;
 468
 469         return room;
 470 }
 471
 472 static int gb_tty_chars_in_buffer(struct tty_struct *tty)
 473 {
 474         struct gb_tty *gb_tty = tty->driver_data;
 475         unsigned long flags;
 476         int chars;
 477
 478         spin_lock_irqsave(&gb_tty->write_lock, flags);
 479         chars = kfifo_len(&gb_tty->write_fifo);
 480         if (gb_tty->credits < GB_UART_FIRMWARE_CREDITS)
 481                 chars += GB_UART_FIRMWARE_CREDITS - gb_tty->credits;
 482         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 483
 484         return chars;
 485 }
 486
 487 static int gb_tty_break_ctl(struct tty_struct *tty, int state)
 488 {
 489         struct gb_tty *gb_tty = tty->driver_data;
 490
 491         return send_break(gb_tty, state ? 1 : 0);
 492 }
 493
 494 static void gb_tty_set_termios(struct tty_struct *tty,
 495                                struct ktermios *termios_old)
 496 {
 497         struct gb_tty *gb_tty = tty->driver_data;
 498         struct ktermios *termios = &tty->termios;
 499         struct gb_tty_line_coding newline;
 500         u8 newctrl = gb_tty->ctrlout;
 501
 502         newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
 503         newline.format = termios->c_cflag & CSTOPB ?
 504                                 GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
 505         newline.parity = termios->c_cflag & PARENB ?
 506                                 (termios->c_cflag & PARODD ? 1 : 2) +
 507                                 (termios->c_cflag & CMSPAR ? 2 : 0) : 0;
 508
 509         switch (termios->c_cflag & CSIZE) {
 510         case CS5:
 511                 newline.data_bits = 5;
 512                 break;
 513         case CS6:
 514                 newline.data_bits = 6;
 515                 break;
 516         case CS7:
 517                 newline.data_bits = 7;
 518                 break;
 519         case CS8:
 520         default:
 521                 newline.data_bits = 8;
 522                 break;
 523         }
 524
 525         /* FIXME: needs to clear unsupported bits in the termios */
 526         gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
 527
 528         if (C_BAUD(tty) == B0) {
 529                 newline.rate = gb_tty->line_coding.rate;
 530                 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 531         } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
 532                 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 533         }
 534
 535         if (newctrl != gb_tty->ctrlout) {
 536                 gb_tty->ctrlout = newctrl;
 537                 send_control(gb_tty, newctrl);
 538         }
 539
 540         if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
 541                 newline.flow_control = GB_SERIAL_AUTO_RTSCTS_EN;
 542         else
 543                 newline.flow_control = 0;
 544
 545         if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
 546                 memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
 547                 send_line_coding(gb_tty);
 548         }
 549 }
 550
 551 static int gb_tty_tiocmget(struct tty_struct *tty)
 552 {
 553         struct gb_tty *gb_tty = tty->driver_data;
 554
 555         return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
 556                (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
 557                (gb_tty->ctrlin  & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
 558                (gb_tty->ctrlin  & GB_UART_CTRL_RI  ? TIOCM_RI  : 0) |
 559                (gb_tty->ctrlin  & GB_UART_CTRL_DCD ? TIOCM_CD  : 0) |
 560                TIOCM_CTS;
 561 }
 562
 563 static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
 564                            unsigned int clear)
 565 {
 566         struct gb_tty *gb_tty = tty->driver_data;
 567         u8 newctrl = gb_tty->ctrlout;
 568
 569         set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
 570               (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
 571         clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
 572                 (clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
 573
 574         newctrl = (newctrl & ~clear) | set;
 575         if (gb_tty->ctrlout == newctrl)
 576                 return 0;
 577
 578         gb_tty->ctrlout = newctrl;
 579         return send_control(gb_tty, newctrl);
 580 }
 581
 582 static void gb_tty_throttle(struct tty_struct *tty)
 583 {
 584         struct gb_tty *gb_tty = tty->driver_data;
 585         unsigned char stop_char;
 586         int retval;
 587
 588         if (I_IXOFF(tty)) {
 589                 stop_char = STOP_CHAR(tty);
 590                 retval = gb_tty_write(tty, &stop_char, 1);
 591                 if (retval <= 0)
 592                         return;
 593         }
 594
 595         if (tty->termios.c_cflag & CRTSCTS) {
 596                 gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
 597                 retval = send_control(gb_tty, gb_tty->ctrlout);
 598         }
 599 }
 600
 601 static void gb_tty_unthrottle(struct tty_struct *tty)
 602 {
 603         struct gb_tty *gb_tty = tty->driver_data;
 604         unsigned char start_char;
 605         int retval;
 606
 607         if (I_IXOFF(tty)) {
 608                 start_char = START_CHAR(tty);
 609                 retval = gb_tty_write(tty, &start_char, 1);
 610                 if (retval <= 0)
 611                         return;
 612         }
 613
 614         if (tty->termios.c_cflag & CRTSCTS) {
 615                 gb_tty->ctrlout |= GB_UART_CTRL_RTS;
 616                 retval = send_control(gb_tty, gb_tty->ctrlout);
 617         }
 618 }
 619
 620 static int get_serial_info(struct gb_tty *gb_tty,
 621                            struct serial_struct __user *info)
 622 {
 623         struct serial_struct tmp;
 624
 625         memset(&tmp, 0, sizeof(tmp));
 626         tmp.type = PORT_16550A;
 627         tmp.line = gb_tty->minor;
 628         tmp.xmit_fifo_size = 16;
 629         tmp.baud_base = 9600;
 630         tmp.close_delay = gb_tty->port.close_delay / 10;
 631         tmp.closing_wait =
 632                 gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 633                 ASYNC_CLOSING_WAIT_NONE : gb_tty->port.closing_wait / 10;
 634
 635         if (copy_to_user(info, &tmp, sizeof(tmp)))
 636                 return -EFAULT;
 637         return 0;
 638 }
 639
 640 static int set_serial_info(struct gb_tty *gb_tty,
 641                            struct serial_struct __user *newinfo)
 642 {
 643         struct serial_struct new_serial;
 644         unsigned int closing_wait;
 645         unsigned int close_delay;
 646         int retval = 0;
 647
 648         if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
 649                 return -EFAULT;
 650
 651         close_delay = new_serial.close_delay * 10;
 652         closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 653                         ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
 654
 655         mutex_lock(&gb_tty->port.mutex);
 656         if (!capable(CAP_SYS_ADMIN)) {
 657                 if ((close_delay != gb_tty->port.close_delay) ||
 658                     (closing_wait != gb_tty->port.closing_wait))
 659                         retval = -EPERM;
 660         } else {
 661                 gb_tty->port.close_delay = close_delay;
 662                 gb_tty->port.closing_wait = closing_wait;
 663         }
 664         mutex_unlock(&gb_tty->port.mutex);
 665         return retval;
 666 }
 667
 668 static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
 669 {
 670         int retval = 0;
 671         DECLARE_WAITQUEUE(wait, current);
 672         struct async_icount old;
 673         struct async_icount new;
 674
 675         if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
 676                 return -EINVAL;
 677
 678         do {
 679                 spin_lock_irq(&gb_tty->read_lock);
 680                 old = gb_tty->oldcount;
 681                 new = gb_tty->iocount;
 682                 gb_tty->oldcount = new;
 683                 spin_unlock_irq(&gb_tty->read_lock);
 684
 685                 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
 686                         break;
 687                 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
 688                         break;
 689                 if ((arg & TIOCM_RI) && (old.rng != new.rng))
 690                         break;
 691
 692                 add_wait_queue(&gb_tty->wioctl, &wait);
 693                 set_current_state(TASK_INTERRUPTIBLE);
 694                 schedule();
 695                 remove_wait_queue(&gb_tty->wioctl, &wait);
 696                 if (gb_tty->disconnected) {
 697                         if (arg & TIOCM_CD)
 698                                 break;
 699                         retval = -ENODEV;
 700                 } else if (signal_pending(current)) {
 701                         retval = -ERESTARTSYS;
 702                 }
 703         } while (!retval);
 704
 705         return retval;
 706 }
 707
 708 static int gb_tty_get_icount(struct tty_struct *tty,
 709                              struct serial_icounter_struct *icount)
 710 {
 711         struct gb_tty *gb_tty = tty->driver_data;
 712
 713         icount->dsr = gb_tty->iocount.dsr;
 714         icount->rng = gb_tty->iocount.rng;
 715         icount->dcd = gb_tty->iocount.dcd;
 716         icount->frame = gb_tty->iocount.frame;
 717         icount->overrun = gb_tty->iocount.overrun;
 718         icount->parity = gb_tty->iocount.parity;
 719         icount->brk = gb_tty->iocount.brk;
 720
 721         return 0;
 722 }
 723
 724 static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
 725                         unsigned long arg)
 726 {
 727         struct gb_tty *gb_tty = tty->driver_data;
 728
 729         switch (cmd) {
 730         case TIOCGSERIAL:
 731                 return get_serial_info(gb_tty,
 732                                        (struct serial_struct __user *)arg);
 733         case TIOCSSERIAL:
 734                 return set_serial_info(gb_tty,
 735                                        (struct serial_struct __user *)arg);
 736         case TIOCMIWAIT:
 737                 return wait_serial_change(gb_tty, arg);
 738         }
 739
 740         return -ENOIOCTLCMD;
 741 }
 742
 743 static void gb_tty_dtr_rts(struct tty_port *port, int on)
 744 {
 745         struct gb_tty *gb_tty;
 746         u8 newctrl;
 747
 748         gb_tty = container_of(port, struct gb_tty, port);
 749         newctrl = gb_tty->ctrlout;
 750
 751         if (on)
 752                 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 753         else
 754                 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
 755
 756         gb_tty->ctrlout = newctrl;
 757         send_control(gb_tty, newctrl);
 758 }
 759
 760 static int gb_tty_port_activate(struct tty_port *port,
 761                                 struct tty_struct *tty)
 762 {
 763         struct gb_tty *gb_tty;
 764
 765         gb_tty = container_of(port, struct gb_tty, port);
 766
 767         return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
 768 }
 769
 770 static void gb_tty_port_shutdown(struct tty_port *port)
 771 {
 772         struct gb_tty *gb_tty;
 773         unsigned long flags;
 774         int ret;
 775
 776         gb_tty = container_of(port, struct gb_tty, port);
 777
 778         gb_tty->close_pending = true;
 779
 780         cancel_work_sync(&gb_tty->tx_work);
 781
 782         spin_lock_irqsave(&gb_tty->write_lock, flags);
 783         kfifo_reset_out(&gb_tty->write_fifo);
 784         spin_unlock_irqrestore(&gb_tty->write_lock, flags);
 785
 786         if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
 787                 goto out;
 788
 789         ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
 790         if (ret) {
 791                 dev_err(&gb_tty->gbphy_dev->dev,
 792                         "error flushing transmitter: %d\n", ret);
 793         }
 794
 795         gb_uart_wait_for_all_credits(gb_tty);
 796
 797 out:
 798         gb_tty->close_pending = false;
 799
 800         gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
 801 }
 802
 803 static void gb_tty_port_destruct(struct tty_port *port)
 804 {
 805         struct gb_tty *gb_tty = container_of(port, struct gb_tty, port);
 806
 807         if (gb_tty->minor != GB_NUM_MINORS)
 808                 release_minor(gb_tty);
 809         kfifo_free(&gb_tty->write_fifo);
 810         kfree(gb_tty->buffer);
 811         kfree(gb_tty);
 812 }
 813
 814 static const struct tty_operations gb_ops = {
 815         .install =              gb_tty_install,
 816         .open =                 gb_tty_open,
 817         .close =                gb_tty_close,
 818         .cleanup =              gb_tty_cleanup,
 819         .hangup =               gb_tty_hangup,
 820         .write =                gb_tty_write,
 821         .write_room =           gb_tty_write_room,
 822         .ioctl =                gb_tty_ioctl,
 823         .throttle =             gb_tty_throttle,
 824         .unthrottle =           gb_tty_unthrottle,
 825         .chars_in_buffer =      gb_tty_chars_in_buffer,
 826         .break_ctl =            gb_tty_break_ctl,
 827         .set_termios =          gb_tty_set_termios,
 828         .tiocmget =             gb_tty_tiocmget,
 829         .tiocmset =             gb_tty_tiocmset,
 830         .get_icount =           gb_tty_get_icount,
 831 };
 832
 833 static const struct tty_port_operations gb_port_ops = {
 834         .dtr_rts =              gb_tty_dtr_rts,
 835         .activate =             gb_tty_port_activate,
 836         .shutdown =             gb_tty_port_shutdown,
 837         .destruct =             gb_tty_port_destruct,
 838 };
 839
 840 static int gb_uart_probe(struct gbphy_device *gbphy_dev,
 841                          const struct gbphy_device_id *id)
 842 {
 843         struct gb_connection *connection;
 844         size_t max_payload;
 845         struct gb_tty *gb_tty;
 846         struct device *tty_dev;
 847         int retval;
 848         int minor;
 849
 850         connection = gb_connection_create(gbphy_dev->bundle,
 851                                           le16_to_cpu(gbphy_dev->cport_desc->id),
 852                                           gb_uart_request_handler);
 853         if (IS_ERR(connection))
 854                 return PTR_ERR(connection);
 855
 856         max_payload = gb_operation_get_payload_size_max(connection);
 857         if (max_payload < sizeof(struct gb_uart_send_data_request)) {
 858                 retval = -EINVAL;
 859                 goto exit_connection_destroy;
 860         }
 861
 862         gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
 863         if (!gb_tty) {
 864                 retval = -ENOMEM;
 865                 goto exit_connection_destroy;
 866         }
 867
 868         tty_port_init(&gb_tty->port);
 869         gb_tty->port.ops = &gb_port_ops;
 870         gb_tty->minor = GB_NUM_MINORS;
 871
 872         gb_tty->buffer_payload_max = max_payload -
 873                         sizeof(struct gb_uart_send_data_request);
 874
 875         gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
 876         if (!gb_tty->buffer) {
 877                 retval = -ENOMEM;
 878                 goto exit_put_port;
 879         }
 880
 881         INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
 882
 883         retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
 884                              GFP_KERNEL);
 885         if (retval)
 886                 goto exit_put_port;
 887
 888         gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
 889         init_completion(&gb_tty->credits_complete);
 890
 891         minor = alloc_minor(gb_tty);
 892         if (minor < 0) {
 893                 if (minor == -ENOSPC) {
 894                         dev_err(&gbphy_dev->dev,
 895                                 "no more free minor numbers\n");
 896                         retval = -ENODEV;
 897                 } else {
 898                         retval = minor;
 899                 }
 900                 goto exit_put_port;
 901         }
 902
 903         gb_tty->minor = minor;
 904         spin_lock_init(&gb_tty->write_lock);
 905         spin_lock_init(&gb_tty->read_lock);
 906         init_waitqueue_head(&gb_tty->wioctl);
 907         mutex_init(&gb_tty->mutex);
 908
 909         gb_tty->connection = connection;
 910         gb_tty->gbphy_dev = gbphy_dev;
 911         gb_connection_set_data(connection, gb_tty);
 912         gb_gbphy_set_data(gbphy_dev, gb_tty);
 913
 914         retval = gb_connection_enable_tx(connection);
 915         if (retval)
 916                 goto exit_put_port;
 917
 918         send_control(gb_tty, gb_tty->ctrlout);
 919
 920         /* initialize the uart to be 9600n81 */
 921         gb_tty->line_coding.rate = cpu_to_le32(9600);
 922         gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
 923         gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
 924         gb_tty->line_coding.data_bits = 8;
 925         send_line_coding(gb_tty);
 926
 927         retval = gb_connection_enable(connection);
 928         if (retval)
 929                 goto exit_connection_disable;
 930
 931         tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
 932                                            &gbphy_dev->dev);
 933         if (IS_ERR(tty_dev)) {
 934                 retval = PTR_ERR(tty_dev);
 935                 goto exit_connection_disable;
 936         }
 937
 938         gbphy_runtime_put_autosuspend(gbphy_dev);
 939         return 0;
 940
 941 exit_connection_disable:
 942         gb_connection_disable(connection);
 943 exit_put_port:
 944         tty_port_put(&gb_tty->port);
 945 exit_connection_destroy:
 946         gb_connection_destroy(connection);
 947
 948         return retval;
 949 }
 950
 951 static void gb_uart_remove(struct gbphy_device *gbphy_dev)
 952 {
 953         struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
 954         struct gb_connection *connection = gb_tty->connection;
 955         struct tty_struct *tty;
 956         int ret;
 957
 958         ret = gbphy_runtime_get_sync(gbphy_dev);
 959         if (ret)
 960                 gbphy_runtime_get_noresume(gbphy_dev);
 961
 962         mutex_lock(&gb_tty->mutex);
 963         gb_tty->disconnected = true;
 964
 965         wake_up_all(&gb_tty->wioctl);
 966         mutex_unlock(&gb_tty->mutex);
 967
 968         tty = tty_port_tty_get(&gb_tty->port);
 969         if (tty) {
 970                 tty_vhangup(tty);
 971                 tty_kref_put(tty);
 972         }
 973
 974         gb_connection_disable_rx(connection);
 975         tty_unregister_device(gb_tty_driver, gb_tty->minor);
 976
 977         gb_connection_disable(connection);
 978         gb_connection_destroy(connection);
 979
 980         tty_port_put(&gb_tty->port);
 981 }
 982
 983 static int gb_tty_init(void)
 984 {
 985         int retval = 0;
 986
 987         gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
 988         if (IS_ERR(gb_tty_driver)) {
 989                 pr_err("Can not allocate tty driver\n");
 990                 retval = -ENOMEM;
 991                 goto fail_unregister_dev;
 992         }
 993
 994         gb_tty_driver->driver_name = "gb";
 995         gb_tty_driver->name = GB_NAME;
 996         gb_tty_driver->major = 0;
 997         gb_tty_driver->minor_start = 0;
 998         gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
 999         gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
1000         gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
1001         gb_tty_driver->init_termios = tty_std_termios;
1002         gb_tty_driver->init_termios.c_cflag = B9600 | CS8 |
1003                 CREAD | HUPCL | CLOCAL;
1004         tty_set_operations(gb_tty_driver, &gb_ops);
1005
1006         retval = tty_register_driver(gb_tty_driver);
1007         if (retval) {
1008                 pr_err("Can not register tty driver: %d\n", retval);
1009                 goto fail_put_gb_tty;
1010         }
1011
1012         return 0;
1013
1014 fail_put_gb_tty:
1015         put_tty_driver(gb_tty_driver);
1016 fail_unregister_dev:
1017         return retval;
1018 }
1019
1020 static void gb_tty_exit(void)
1021 {
1022         tty_unregister_driver(gb_tty_driver);
1023         put_tty_driver(gb_tty_driver);
1024         idr_destroy(&tty_minors);
1025 }
1026
1027 static const struct gbphy_device_id gb_uart_id_table[] = {
1028         { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
1029         { },
1030 };
1031 MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
1032
1033 static struct gbphy_driver uart_driver = {
1034         .name           = "uart",
1035         .probe          = gb_uart_probe,
1036         .remove         = gb_uart_remove,
1037         .id_table       = gb_uart_id_table,
1038 };
1039
1040 static int gb_uart_driver_init(void)
1041 {
1042         int ret;
1043
1044         ret = gb_tty_init();
1045         if (ret)
1046                 return ret;
1047
1048         ret = gb_gbphy_register(&uart_driver);
1049         if (ret) {
1050                 gb_tty_exit();
1051                 return ret;
1052         }
1053
1054         return 0;
1055 }
1056 module_init(gb_uart_driver_init);
1057
1058 static void gb_uart_driver_exit(void)
1059 {
1060         gb_gbphy_deregister(&uart_driver);
1061         gb_tty_exit();
1062 }
1063
1064 module_exit(gb_uart_driver_exit);
1065 MODULE_LICENSE("GPL v2");