drivers/tty/ipwireless/tty.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * IPWireless 3G PCMCIA Network Driver
   4  *
   5  * Original code
   6  *   by Stephen Blackheath <[email protected]>,
   7  *      Ben Martel <[email protected]>
   8  *
   9  * Copyrighted as follows:
  10  *   Copyright (C) 2004 by Symmetric Systems Ltd (NZ)
  11  *
  12  * Various driver changes and rewrites, port to new kernels
  13  *   Copyright (C) 2006-2007 Jiri Kosina
  14  *
  15  * Misc code cleanups and updates
  16  *   Copyright (C) 2007 David Sterba
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/mutex.h>
  22 #include <linux/ppp_defs.h>
  23 #include <linux/if.h>
  24 #include <linux/ppp-ioctl.h>
  25 #include <linux/sched.h>
  26 #include <linux/serial.h>
  27 #include <linux/slab.h>
  28 #include <linux/tty.h>
  29 #include <linux/tty_driver.h>
  30 #include <linux/tty_flip.h>
  31 #include <linux/uaccess.h>
  32
  33 #include "tty.h"
  34 #include "network.h"
  35 #include "hardware.h"
  36 #include "main.h"
  37
  38 #define IPWIRELESS_PCMCIA_START         (0)
  39 #define IPWIRELESS_PCMCIA_MINORS        (24)
  40 #define IPWIRELESS_PCMCIA_MINOR_RANGE   (8)
  41
  42 #define TTYTYPE_MODEM    (0)
  43 #define TTYTYPE_MONITOR  (1)
  44 #define TTYTYPE_RAS_RAW  (2)
  45
  46 struct ipw_tty {
  47         struct tty_port port;
  48         int index;
  49         struct ipw_hardware *hardware;
  50         unsigned int channel_idx;
  51         unsigned int secondary_channel_idx;
  52         int tty_type;
  53         struct ipw_network *network;
  54         unsigned int control_lines;
  55         struct mutex ipw_tty_mutex;
  56         int tx_bytes_queued;
  57         int closing;
  58 };
  59
  60 static struct ipw_tty *ttys[IPWIRELESS_PCMCIA_MINORS];
  61
  62 static struct tty_driver *ipw_tty_driver;
  63
  64 static char *tty_type_name(int tty_type)
  65 {
  66         static char *channel_names[] = {
  67                 "modem",
  68                 "monitor",
  69                 "RAS-raw"
  70         };
  71
  72         return channel_names[tty_type];
  73 }
  74
  75 static struct ipw_tty *get_tty(int index)
  76 {
  77         /*
  78          * The 'ras_raw' channel is only available when 'loopback' mode
  79          * is enabled.
  80          * Number of minor starts with 16 (_RANGE * _RAS_RAW).
  81          */
  82         if (!ipwireless_loopback && index >=
  83                          IPWIRELESS_PCMCIA_MINOR_RANGE * TTYTYPE_RAS_RAW)
  84                 return NULL;
  85
  86         return ttys[index];
  87 }
  88
  89 static int ipw_open(struct tty_struct *linux_tty, struct file *filp)
  90 {
  91         struct ipw_tty *tty = get_tty(linux_tty->index);
  92
  93         if (!tty)
  94                 return -ENODEV;
  95
  96         mutex_lock(&tty->ipw_tty_mutex);
  97         if (tty->port.count == 0)
  98                 tty->tx_bytes_queued = 0;
  99
 100         tty->port.count++;
 101
 102         tty->port.tty = linux_tty;
 103         linux_tty->driver_data = tty;
 104         tty->port.low_latency = 1;
 105
 106         if (tty->tty_type == TTYTYPE_MODEM)
 107                 ipwireless_ppp_open(tty->network);
 108
 109         mutex_unlock(&tty->ipw_tty_mutex);
 110
 111         return 0;
 112 }
 113
 114 static void do_ipw_close(struct ipw_tty *tty)
 115 {
 116         tty->port.count--;
 117
 118         if (tty->port.count == 0) {
 119                 struct tty_struct *linux_tty = tty->port.tty;
 120
 121                 if (linux_tty != NULL) {
 122                         tty->port.tty = NULL;
 123                         linux_tty->driver_data = NULL;
 124
 125                         if (tty->tty_type == TTYTYPE_MODEM)
 126                                 ipwireless_ppp_close(tty->network);
 127                 }
 128         }
 129 }
 130
 131 static void ipw_hangup(struct tty_struct *linux_tty)
 132 {
 133         struct ipw_tty *tty = linux_tty->driver_data;
 134
 135         if (!tty)
 136                 return;
 137
 138         mutex_lock(&tty->ipw_tty_mutex);
 139         if (tty->port.count == 0) {
 140                 mutex_unlock(&tty->ipw_tty_mutex);
 141                 return;
 142         }
 143
 144         do_ipw_close(tty);
 145
 146         mutex_unlock(&tty->ipw_tty_mutex);
 147 }
 148
 149 static void ipw_close(struct tty_struct *linux_tty, struct file *filp)
 150 {
 151         ipw_hangup(linux_tty);
 152 }
 153
 154 /* Take data received from hardware, and send it out the tty */
 155 void ipwireless_tty_received(struct ipw_tty *tty, unsigned char *data,
 156                         unsigned int length)
 157 {
 158         int work = 0;
 159
 160         mutex_lock(&tty->ipw_tty_mutex);
 161
 162         if (!tty->port.count) {
 163                 mutex_unlock(&tty->ipw_tty_mutex);
 164                 return;
 165         }
 166         mutex_unlock(&tty->ipw_tty_mutex);
 167
 168         work = tty_insert_flip_string(&tty->port, data, length);
 169
 170         if (work != length)
 171                 printk(KERN_DEBUG IPWIRELESS_PCCARD_NAME
 172                                 ": %d chars not inserted to flip buffer!\n",
 173                                 length - work);
 174
 175         if (work)
 176                 tty_flip_buffer_push(&tty->port);
 177 }
 178
 179 static void ipw_write_packet_sent_callback(void *callback_data,
 180                                            unsigned int packet_length)
 181 {
 182         struct ipw_tty *tty = callback_data;
 183
 184         /*
 185          * Packet has been sent, so we subtract the number of bytes from our
 186          * tally of outstanding TX bytes.
 187          */
 188         tty->tx_bytes_queued -= packet_length;
 189 }
 190
 191 static int ipw_write(struct tty_struct *linux_tty,
 192                      const unsigned char *buf, int count)
 193 {
 194         struct ipw_tty *tty = linux_tty->driver_data;
 195         int room, ret;
 196
 197         if (!tty)
 198                 return -ENODEV;
 199
 200         mutex_lock(&tty->ipw_tty_mutex);
 201         if (!tty->port.count) {
 202                 mutex_unlock(&tty->ipw_tty_mutex);
 203                 return -EINVAL;
 204         }
 205
 206         room = IPWIRELESS_TX_QUEUE_SIZE - tty->tx_bytes_queued;
 207         if (room < 0)
 208                 room = 0;
 209         /* Don't allow caller to write any more than we have room for */
 210         if (count > room)
 211                 count = room;
 212
 213         if (count == 0) {
 214                 mutex_unlock(&tty->ipw_tty_mutex);
 215                 return 0;
 216         }
 217
 218         ret = ipwireless_send_packet(tty->hardware, IPW_CHANNEL_RAS,
 219                                buf, count,
 220                                ipw_write_packet_sent_callback, tty);
 221         if (ret == -1) {
 222                 mutex_unlock(&tty->ipw_tty_mutex);
 223                 return 0;
 224         }
 225
 226         tty->tx_bytes_queued += count;
 227         mutex_unlock(&tty->ipw_tty_mutex);
 228
 229         return count;
 230 }
 231
 232 static int ipw_write_room(struct tty_struct *linux_tty)
 233 {
 234         struct ipw_tty *tty = linux_tty->driver_data;
 235         int room;
 236
 237         /* FIXME: Exactly how is the tty object locked here .. */
 238         if (!tty)
 239                 return -ENODEV;
 240
 241         if (!tty->port.count)
 242                 return -EINVAL;
 243
 244         room = IPWIRELESS_TX_QUEUE_SIZE - tty->tx_bytes_queued;
 245         if (room < 0)
 246                 room = 0;
 247
 248         return room;
 249 }
 250
 251 static int ipwireless_get_serial_info(struct ipw_tty *tty,
 252                                       struct serial_struct __user *retinfo)
 253 {
 254         struct serial_struct tmp;
 255
 256         memset(&tmp, 0, sizeof(tmp));
 257         tmp.type = PORT_UNKNOWN;
 258         tmp.line = tty->index;
 259         tmp.baud_base = 115200;
 260
 261         if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
 262                 return -EFAULT;
 263
 264         return 0;
 265 }
 266
 267 static int ipw_chars_in_buffer(struct tty_struct *linux_tty)
 268 {
 269         struct ipw_tty *tty = linux_tty->driver_data;
 270
 271         if (!tty)
 272                 return 0;
 273
 274         if (!tty->port.count)
 275                 return 0;
 276
 277         return tty->tx_bytes_queued;
 278 }
 279
 280 static int get_control_lines(struct ipw_tty *tty)
 281 {
 282         unsigned int my = tty->control_lines;
 283         unsigned int out = 0;
 284
 285         if (my & IPW_CONTROL_LINE_RTS)
 286                 out |= TIOCM_RTS;
 287         if (my & IPW_CONTROL_LINE_DTR)
 288                 out |= TIOCM_DTR;
 289         if (my & IPW_CONTROL_LINE_CTS)
 290                 out |= TIOCM_CTS;
 291         if (my & IPW_CONTROL_LINE_DSR)
 292                 out |= TIOCM_DSR;
 293         if (my & IPW_CONTROL_LINE_DCD)
 294                 out |= TIOCM_CD;
 295
 296         return out;
 297 }
 298
 299 static int set_control_lines(struct ipw_tty *tty, unsigned int set,
 300                              unsigned int clear)
 301 {
 302         int ret;
 303
 304         if (set & TIOCM_RTS) {
 305                 ret = ipwireless_set_RTS(tty->hardware, tty->channel_idx, 1);
 306                 if (ret)
 307                         return ret;
 308                 if (tty->secondary_channel_idx != -1) {
 309                         ret = ipwireless_set_RTS(tty->hardware,
 310                                           tty->secondary_channel_idx, 1);
 311                         if (ret)
 312                                 return ret;
 313                 }
 314         }
 315         if (set & TIOCM_DTR) {
 316                 ret = ipwireless_set_DTR(tty->hardware, tty->channel_idx, 1);
 317                 if (ret)
 318                         return ret;
 319                 if (tty->secondary_channel_idx != -1) {
 320                         ret = ipwireless_set_DTR(tty->hardware,
 321                                           tty->secondary_channel_idx, 1);
 322                         if (ret)
 323                                 return ret;
 324                 }
 325         }
 326         if (clear & TIOCM_RTS) {
 327                 ret = ipwireless_set_RTS(tty->hardware, tty->channel_idx, 0);
 328                 if (tty->secondary_channel_idx != -1) {
 329                         ret = ipwireless_set_RTS(tty->hardware,
 330                                           tty->secondary_channel_idx, 0);
 331                         if (ret)
 332                                 return ret;
 333                 }
 334         }
 335         if (clear & TIOCM_DTR) {
 336                 ret = ipwireless_set_DTR(tty->hardware, tty->channel_idx, 0);
 337                 if (tty->secondary_channel_idx != -1) {
 338                         ret = ipwireless_set_DTR(tty->hardware,
 339                                           tty->secondary_channel_idx, 0);
 340                         if (ret)
 341                                 return ret;
 342                 }
 343         }
 344         return 0;
 345 }
 346
 347 static int ipw_tiocmget(struct tty_struct *linux_tty)
 348 {
 349         struct ipw_tty *tty = linux_tty->driver_data;
 350         /* FIXME: Exactly how is the tty object locked here .. */
 351
 352         if (!tty)
 353                 return -ENODEV;
 354
 355         if (!tty->port.count)
 356                 return -EINVAL;
 357
 358         return get_control_lines(tty);
 359 }
 360
 361 static int
 362 ipw_tiocmset(struct tty_struct *linux_tty,
 363              unsigned int set, unsigned int clear)
 364 {
 365         struct ipw_tty *tty = linux_tty->driver_data;
 366         /* FIXME: Exactly how is the tty object locked here .. */
 367
 368         if (!tty)
 369                 return -ENODEV;
 370
 371         if (!tty->port.count)
 372                 return -EINVAL;
 373
 374         return set_control_lines(tty, set, clear);
 375 }
 376
 377 static int ipw_ioctl(struct tty_struct *linux_tty,
 378                      unsigned int cmd, unsigned long arg)
 379 {
 380         struct ipw_tty *tty = linux_tty->driver_data;
 381
 382         if (!tty)
 383                 return -ENODEV;
 384
 385         if (!tty->port.count)
 386                 return -EINVAL;
 387
 388         /* FIXME: Exactly how is the tty object locked here .. */
 389
 390         switch (cmd) {
 391         case TIOCGSERIAL:
 392                 return ipwireless_get_serial_info(tty, (void __user *) arg);
 393
 394         case TIOCSSERIAL:
 395                 return 0;       /* Keeps the PCMCIA scripts happy. */
 396         }
 397
 398         if (tty->tty_type == TTYTYPE_MODEM) {
 399                 switch (cmd) {
 400                 case PPPIOCGCHAN:
 401                         {
 402                                 int chan = ipwireless_ppp_channel_index(
 403                                                         tty->network);
 404
 405                                 if (chan < 0)
 406                                         return -ENODEV;
 407                                 if (put_user(chan, (int __user *) arg))
 408                                         return -EFAULT;
 409                         }
 410                         return 0;
 411
 412                 case PPPIOCGUNIT:
 413                         {
 414                                 int unit = ipwireless_ppp_unit_number(
 415                                                 tty->network);
 416
 417                                 if (unit < 0)
 418                                         return -ENODEV;
 419                                 if (put_user(unit, (int __user *) arg))
 420                                         return -EFAULT;
 421                         }
 422                         return 0;
 423
 424                 case FIONREAD:
 425                         {
 426                                 int val = 0;
 427
 428                                 if (put_user(val, (int __user *) arg))
 429                                         return -EFAULT;
 430                         }
 431                         return 0;
 432                 case TCFLSH:
 433                         return tty_perform_flush(linux_tty, arg);
 434                 }
 435         }
 436         return -ENOIOCTLCMD;
 437 }
 438
 439 static int add_tty(int j,
 440                     struct ipw_hardware *hardware,
 441                     struct ipw_network *network, int channel_idx,
 442                     int secondary_channel_idx, int tty_type)
 443 {
 444         ttys[j] = kzalloc(sizeof(struct ipw_tty), GFP_KERNEL);
 445         if (!ttys[j])
 446                 return -ENOMEM;
 447         ttys[j]->index = j;
 448         ttys[j]->hardware = hardware;
 449         ttys[j]->channel_idx = channel_idx;
 450         ttys[j]->secondary_channel_idx = secondary_channel_idx;
 451         ttys[j]->network = network;
 452         ttys[j]->tty_type = tty_type;
 453         mutex_init(&ttys[j]->ipw_tty_mutex);
 454         tty_port_init(&ttys[j]->port);
 455
 456         tty_port_register_device(&ttys[j]->port, ipw_tty_driver, j, NULL);
 457         ipwireless_associate_network_tty(network, channel_idx, ttys[j]);
 458
 459         if (secondary_channel_idx != -1)
 460                 ipwireless_associate_network_tty(network,
 461                                                  secondary_channel_idx,
 462                                                  ttys[j]);
 463         /* check if we provide raw device (if loopback is enabled) */
 464         if (get_tty(j))
 465                 printk(KERN_INFO IPWIRELESS_PCCARD_NAME
 466                        ": registering %s device ttyIPWp%d\n",
 467                        tty_type_name(tty_type), j);
 468
 469         return 0;
 470 }
 471
 472 struct ipw_tty *ipwireless_tty_create(struct ipw_hardware *hardware,
 473                                       struct ipw_network *network)
 474 {
 475         int i, j;
 476
 477         for (i = 0; i < IPWIRELESS_PCMCIA_MINOR_RANGE; i++) {
 478                 int allfree = 1;
 479
 480                 for (j = i; j < IPWIRELESS_PCMCIA_MINORS;
 481                                 j += IPWIRELESS_PCMCIA_MINOR_RANGE)
 482                         if (ttys[j] != NULL) {
 483                                 allfree = 0;
 484                                 break;
 485                         }
 486
 487                 if (allfree) {
 488                         j = i;
 489
 490                         if (add_tty(j, hardware, network,
 491                                         IPW_CHANNEL_DIALLER, IPW_CHANNEL_RAS,
 492                                         TTYTYPE_MODEM))
 493                                 return NULL;
 494
 495                         j += IPWIRELESS_PCMCIA_MINOR_RANGE;
 496                         if (add_tty(j, hardware, network,
 497                                         IPW_CHANNEL_DIALLER, -1,
 498                                         TTYTYPE_MONITOR))
 499                                 return NULL;
 500
 501                         j += IPWIRELESS_PCMCIA_MINOR_RANGE;
 502                         if (add_tty(j, hardware, network,
 503                                         IPW_CHANNEL_RAS, -1,
 504                                         TTYTYPE_RAS_RAW))
 505                                 return NULL;
 506
 507                         return ttys[i];
 508                 }
 509         }
 510         return NULL;
 511 }
 512
 513 /*
 514  * Must be called before ipwireless_network_free().
 515  */
 516 void ipwireless_tty_free(struct ipw_tty *tty)
 517 {
 518         int j;
 519         struct ipw_network *network = ttys[tty->index]->network;
 520
 521         for (j = tty->index; j < IPWIRELESS_PCMCIA_MINORS;
 522                         j += IPWIRELESS_PCMCIA_MINOR_RANGE) {
 523                 struct ipw_tty *ttyj = ttys[j];
 524
 525                 if (ttyj) {
 526                         mutex_lock(&ttyj->ipw_tty_mutex);
 527                         if (get_tty(j))
 528                                 printk(KERN_INFO IPWIRELESS_PCCARD_NAME
 529                                        ": deregistering %s device ttyIPWp%d\n",
 530                                        tty_type_name(ttyj->tty_type), j);
 531                         ttyj->closing = 1;
 532                         if (ttyj->port.tty != NULL) {
 533                                 mutex_unlock(&ttyj->ipw_tty_mutex);
 534                                 tty_vhangup(ttyj->port.tty);
 535                                 /* FIXME: Exactly how is the tty object locked here
 536                                    against a parallel ioctl etc */
 537                                 /* FIXME2: hangup does not mean all processes
 538                                  * are gone */
 539                                 mutex_lock(&ttyj->ipw_tty_mutex);
 540                         }
 541                         while (ttyj->port.count)
 542                                 do_ipw_close(ttyj);
 543                         ipwireless_disassociate_network_ttys(network,
 544                                                              ttyj->channel_idx);
 545                         tty_unregister_device(ipw_tty_driver, j);
 546                         tty_port_destroy(&ttyj->port);
 547                         ttys[j] = NULL;
 548                         mutex_unlock(&ttyj->ipw_tty_mutex);
 549                         kfree(ttyj);
 550                 }
 551         }
 552 }
 553
 554 static const struct tty_operations tty_ops = {
 555         .open = ipw_open,
 556         .close = ipw_close,
 557         .hangup = ipw_hangup,
 558         .write = ipw_write,
 559         .write_room = ipw_write_room,
 560         .ioctl = ipw_ioctl,
 561         .chars_in_buffer = ipw_chars_in_buffer,
 562         .tiocmget = ipw_tiocmget,
 563         .tiocmset = ipw_tiocmset,
 564 };
 565
 566 int ipwireless_tty_init(void)
 567 {
 568         int result;
 569
 570         ipw_tty_driver = alloc_tty_driver(IPWIRELESS_PCMCIA_MINORS);
 571         if (!ipw_tty_driver)
 572                 return -ENOMEM;
 573
 574         ipw_tty_driver->driver_name = IPWIRELESS_PCCARD_NAME;
 575         ipw_tty_driver->name = "ttyIPWp";
 576         ipw_tty_driver->major = 0;
 577         ipw_tty_driver->minor_start = IPWIRELESS_PCMCIA_START;
 578         ipw_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
 579         ipw_tty_driver->subtype = SERIAL_TYPE_NORMAL;
 580         ipw_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 581         ipw_tty_driver->init_termios = tty_std_termios;
 582         ipw_tty_driver->init_termios.c_cflag =
 583             B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 584         ipw_tty_driver->init_termios.c_ispeed = 9600;
 585         ipw_tty_driver->init_termios.c_ospeed = 9600;
 586         tty_set_operations(ipw_tty_driver, &tty_ops);
 587         result = tty_register_driver(ipw_tty_driver);
 588         if (result) {
 589                 printk(KERN_ERR IPWIRELESS_PCCARD_NAME
 590                        ": failed to register tty driver\n");
 591                 put_tty_driver(ipw_tty_driver);
 592                 return result;
 593         }
 594
 595         return 0;
 596 }
 597
 598 void ipwireless_tty_release(void)
 599 {
 600         int ret;
 601
 602         ret = tty_unregister_driver(ipw_tty_driver);
 603         put_tty_driver(ipw_tty_driver);
 604         if (ret != 0)
 605                 printk(KERN_ERR IPWIRELESS_PCCARD_NAME
 606                         ": tty_unregister_driver failed with code %d\n", ret);
 607 }
 608
 609 int ipwireless_tty_is_modem(struct ipw_tty *tty)
 610 {
 611         return tty->tty_type == TTYTYPE_MODEM;
 612 }
 613
 614 void
 615 ipwireless_tty_notify_control_line_change(struct ipw_tty *tty,
 616                                           unsigned int channel_idx,
 617                                           unsigned int control_lines,
 618                                           unsigned int changed_mask)
 619 {
 620         unsigned int old_control_lines = tty->control_lines;
 621
 622         tty->control_lines = (tty->control_lines & ~changed_mask)
 623                 | (control_lines & changed_mask);
 624
 625         /*
 626          * If DCD is de-asserted, we close the tty so pppd can tell that we
 627          * have gone offline.
 628          */
 629         if ((old_control_lines & IPW_CONTROL_LINE_DCD)
 630                         && !(tty->control_lines & IPW_CONTROL_LINE_DCD)
 631                         && tty->port.tty) {
 632                 tty_hangup(tty->port.tty);
 633         }
 634 }
 635