arch/um/drivers/chan_kern.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/tty.h>
   8 #include <linux/tty_flip.h>
   9 #include "chan_kern.h"
  10 #include "os.h"
  11
  12 #ifdef CONFIG_NOCONFIG_CHAN
  13 static void *not_configged_init(char *str, int device,
  14                                 const struct chan_opts *opts)
  15 {
  16         printk(KERN_ERR "Using a channel type which is configured out of "
  17                "UML\n");
  18         return NULL;
  19 }
  20
  21 static int not_configged_open(int input, int output, int primary, void *data,
  22                               char **dev_out)
  23 {
  24         printk(KERN_ERR "Using a channel type which is configured out of "
  25                "UML\n");
  26         return -ENODEV;
  27 }
  28
  29 static void not_configged_close(int fd, void *data)
  30 {
  31         printk(KERN_ERR "Using a channel type which is configured out of "
  32                "UML\n");
  33 }
  34
  35 static int not_configged_read(int fd, char *c_out, void *data)
  36 {
  37         printk(KERN_ERR "Using a channel type which is configured out of "
  38                "UML\n");
  39         return -EIO;
  40 }
  41
  42 static int not_configged_write(int fd, const char *buf, int len, void *data)
  43 {
  44         printk(KERN_ERR "Using a channel type which is configured out of "
  45                "UML\n");
  46         return -EIO;
  47 }
  48
  49 static int not_configged_console_write(int fd, const char *buf, int len)
  50 {
  51         printk(KERN_ERR "Using a channel type which is configured out of "
  52                "UML\n");
  53         return -EIO;
  54 }
  55
  56 static int not_configged_window_size(int fd, void *data, unsigned short *rows,
  57                                      unsigned short *cols)
  58 {
  59         printk(KERN_ERR "Using a channel type which is configured out of "
  60                "UML\n");
  61         return -ENODEV;
  62 }
  63
  64 static void not_configged_free(void *data)
  65 {
  66         printk(KERN_ERR "Using a channel type which is configured out of "
  67                "UML\n");
  68 }
  69
  70 static const struct chan_ops not_configged_ops = {
  71         .init           = not_configged_init,
  72         .open           = not_configged_open,
  73         .close          = not_configged_close,
  74         .read           = not_configged_read,
  75         .write          = not_configged_write,
  76         .console_write  = not_configged_console_write,
  77         .window_size    = not_configged_window_size,
  78         .free           = not_configged_free,
  79         .winch          = 0,
  80 };
  81 #endif /* CONFIG_NOCONFIG_CHAN */
  82
  83 static void tty_receive_char(struct tty_struct *tty, char ch)
  84 {
  85         if (tty == NULL)
  86                 return;
  87
  88         if (I_IXON(tty) && !I_IXOFF(tty) && !tty->raw) {
  89                 if (ch == STOP_CHAR(tty)) {
  90                         stop_tty(tty);
  91                         return;
  92                 }
  93                 else if (ch == START_CHAR(tty)) {
  94                         start_tty(tty);
  95                         return;
  96                 }
  97         }
  98
  99         tty_insert_flip_char(tty, ch, TTY_NORMAL);
 100 }
 101
 102 static int open_one_chan(struct chan *chan)
 103 {
 104         int fd, err;
 105
 106         if (chan->opened)
 107                 return 0;
 108
 109         if (chan->ops->open == NULL)
 110                 fd = 0;
 111         else fd = (*chan->ops->open)(chan->input, chan->output, chan->primary,
 112                                      chan->data, &chan->dev);
 113         if (fd < 0)
 114                 return fd;
 115
 116         err = os_set_fd_block(fd, 0);
 117         if (err) {
 118                 (*chan->ops->close)(fd, chan->data);
 119                 return err;
 120         }
 121
 122         chan->fd = fd;
 123
 124         chan->opened = 1;
 125         return 0;
 126 }
 127
 128 static int open_chan(struct list_head *chans)
 129 {
 130         struct list_head *ele;
 131         struct chan *chan;
 132         int ret, err = 0;
 133
 134         list_for_each(ele, chans) {
 135                 chan = list_entry(ele, struct chan, list);
 136                 ret = open_one_chan(chan);
 137                 if (chan->primary)
 138                         err = ret;
 139         }
 140         return err;
 141 }
 142
 143 void chan_enable_winch(struct list_head *chans, struct tty_struct *tty)
 144 {
 145         struct list_head *ele;
 146         struct chan *chan;
 147
 148         list_for_each(ele, chans) {
 149                 chan = list_entry(ele, struct chan, list);
 150                 if (chan->primary && chan->output && chan->ops->winch) {
 151                         register_winch(chan->fd, tty);
 152                         return;
 153                 }
 154         }
 155 }
 156
 157 int enable_chan(struct line *line)
 158 {
 159         struct list_head *ele;
 160         struct chan *chan;
 161         int err;
 162
 163         list_for_each(ele, &line->chan_list) {
 164                 chan = list_entry(ele, struct chan, list);
 165                 err = open_one_chan(chan);
 166                 if (err) {
 167                         if (chan->primary)
 168                                 goto out_close;
 169
 170                         continue;
 171                 }
 172
 173                 if (chan->enabled)
 174                         continue;
 175                 err = line_setup_irq(chan->fd, chan->input, chan->output, line,
 176                                      chan);
 177                 if (err)
 178                         goto out_close;
 179
 180                 chan->enabled = 1;
 181         }
 182
 183         return 0;
 184
 185  out_close:
 186         close_chan(&line->chan_list, 0);
 187         return err;
 188 }
 189
 190 /* Items are added in IRQ context, when free_irq can't be called, and
 191  * removed in process context, when it can.
 192  * This handles interrupt sources which disappear, and which need to
 193  * be permanently disabled.  This is discovered in IRQ context, but
 194  * the freeing of the IRQ must be done later.
 195  */
 196 static DEFINE_SPINLOCK(irqs_to_free_lock);
 197 static LIST_HEAD(irqs_to_free);
 198
 199 void free_irqs(void)
 200 {
 201         struct chan *chan;
 202         LIST_HEAD(list);
 203         struct list_head *ele;
 204         unsigned long flags;
 205
 206         spin_lock_irqsave(&irqs_to_free_lock, flags);
 207         list_splice_init(&irqs_to_free, &list);
 208         spin_unlock_irqrestore(&irqs_to_free_lock, flags);
 209
 210         list_for_each(ele, &list) {
 211                 chan = list_entry(ele, struct chan, free_list);
 212
 213                 if (chan->input)
 214                         free_irq(chan->line->driver->read_irq, chan);
 215                 if (chan->output)
 216                         free_irq(chan->line->driver->write_irq, chan);
 217                 chan->enabled = 0;
 218         }
 219 }
 220
 221 static void close_one_chan(struct chan *chan, int delay_free_irq)
 222 {
 223         unsigned long flags;
 224
 225         if (!chan->opened)
 226                 return;
 227
 228         if (delay_free_irq) {
 229                 spin_lock_irqsave(&irqs_to_free_lock, flags);
 230                 list_add(&chan->free_list, &irqs_to_free);
 231                 spin_unlock_irqrestore(&irqs_to_free_lock, flags);
 232         }
 233         else {
 234                 if (chan->input)
 235                         free_irq(chan->line->driver->read_irq, chan);
 236                 if (chan->output)
 237                         free_irq(chan->line->driver->write_irq, chan);
 238                 chan->enabled = 0;
 239         }
 240         if (chan->ops->close != NULL)
 241                 (*chan->ops->close)(chan->fd, chan->data);
 242
 243         chan->opened = 0;
 244         chan->fd = -1;
 245 }
 246
 247 void close_chan(struct list_head *chans, int delay_free_irq)
 248 {
 249         struct chan *chan;
 250
 251         /* Close in reverse order as open in case more than one of them
 252          * refers to the same device and they save and restore that device's
 253          * state.  Then, the first one opened will have the original state,
 254          * so it must be the last closed.
 255          */
 256         list_for_each_entry_reverse(chan, chans, list) {
 257                 close_one_chan(chan, delay_free_irq);
 258         }
 259 }
 260
 261 void deactivate_chan(struct list_head *chans, int irq)
 262 {
 263         struct list_head *ele;
 264
 265         struct chan *chan;
 266         list_for_each(ele, chans) {
 267                 chan = list_entry(ele, struct chan, list);
 268
 269                 if (chan->enabled && chan->input)
 270                         deactivate_fd(chan->fd, irq);
 271         }
 272 }
 273
 274 void reactivate_chan(struct list_head *chans, int irq)
 275 {
 276         struct list_head *ele;
 277         struct chan *chan;
 278
 279         list_for_each(ele, chans) {
 280                 chan = list_entry(ele, struct chan, list);
 281
 282                 if (chan->enabled && chan->input)
 283                         reactivate_fd(chan->fd, irq);
 284         }
 285 }
 286
 287 int write_chan(struct list_head *chans, const char *buf, int len,
 288                int write_irq)
 289 {
 290         struct list_head *ele;
 291         struct chan *chan = NULL;
 292         int n, ret = 0;
 293
 294         if (len == 0)
 295                 return 0;
 296
 297         list_for_each(ele, chans) {
 298                 chan = list_entry(ele, struct chan, list);
 299                 if (!chan->output || (chan->ops->write == NULL))
 300                         continue;
 301
 302                 n = chan->ops->write(chan->fd, buf, len, chan->data);
 303                 if (chan->primary) {
 304                         ret = n;
 305                         if ((ret == -EAGAIN) || ((ret >= 0) && (ret < len)))
 306                                 reactivate_fd(chan->fd, write_irq);
 307                 }
 308         }
 309         return ret;
 310 }
 311
 312 int console_write_chan(struct list_head *chans, const char *buf, int len)
 313 {
 314         struct list_head *ele;
 315         struct chan *chan;
 316         int n, ret = 0;
 317
 318         list_for_each(ele, chans) {
 319                 chan = list_entry(ele, struct chan, list);
 320                 if (!chan->output || (chan->ops->console_write == NULL))
 321                         continue;
 322
 323                 n = chan->ops->console_write(chan->fd, buf, len);
 324                 if (chan->primary)
 325                         ret = n;
 326         }
 327         return ret;
 328 }
 329
 330 int console_open_chan(struct line *line, struct console *co)
 331 {
 332         int err;
 333
 334         err = open_chan(&line->chan_list);
 335         if (err)
 336                 return err;
 337
 338         printk(KERN_INFO "Console initialized on /dev/%s%d\n", co->name,
 339                co->index);
 340         return 0;
 341 }
 342
 343 int chan_window_size(struct list_head *chans, unsigned short *rows_out,
 344                       unsigned short *cols_out)
 345 {
 346         struct list_head *ele;
 347         struct chan *chan;
 348
 349         list_for_each(ele, chans) {
 350                 chan = list_entry(ele, struct chan, list);
 351                 if (chan->primary) {
 352                         if (chan->ops->window_size == NULL)
 353                                 return 0;
 354                         return chan->ops->window_size(chan->fd, chan->data,
 355                                                       rows_out, cols_out);
 356                 }
 357         }
 358         return 0;
 359 }
 360
 361 static void free_one_chan(struct chan *chan, int delay_free_irq)
 362 {
 363         list_del(&chan->list);
 364
 365         close_one_chan(chan, delay_free_irq);
 366
 367         if (chan->ops->free != NULL)
 368                 (*chan->ops->free)(chan->data);
 369
 370         if (chan->primary && chan->output)
 371                 ignore_sigio_fd(chan->fd);
 372         kfree(chan);
 373 }
 374
 375 static void free_chan(struct list_head *chans, int delay_free_irq)
 376 {
 377         struct list_head *ele, *next;
 378         struct chan *chan;
 379
 380         list_for_each_safe(ele, next, chans) {
 381                 chan = list_entry(ele, struct chan, list);
 382                 free_one_chan(chan, delay_free_irq);
 383         }
 384 }
 385
 386 static int one_chan_config_string(struct chan *chan, char *str, int size,
 387                                   char **error_out)
 388 {
 389         int n = 0;
 390
 391         if (chan == NULL) {
 392                 CONFIG_CHUNK(str, size, n, "none", 1);
 393                 return n;
 394         }
 395
 396         CONFIG_CHUNK(str, size, n, chan->ops->type, 0);
 397
 398         if (chan->dev == NULL) {
 399                 CONFIG_CHUNK(str, size, n, "", 1);
 400                 return n;
 401         }
 402
 403         CONFIG_CHUNK(str, size, n, ":", 0);
 404         CONFIG_CHUNK(str, size, n, chan->dev, 0);
 405
 406         return n;
 407 }
 408
 409 static int chan_pair_config_string(struct chan *in, struct chan *out,
 410                                    char *str, int size, char **error_out)
 411 {
 412         int n;
 413
 414         n = one_chan_config_string(in, str, size, error_out);
 415         str += n;
 416         size -= n;
 417
 418         if (in == out) {
 419                 CONFIG_CHUNK(str, size, n, "", 1);
 420                 return n;
 421         }
 422
 423         CONFIG_CHUNK(str, size, n, ",", 1);
 424         n = one_chan_config_string(out, str, size, error_out);
 425         str += n;
 426         size -= n;
 427         CONFIG_CHUNK(str, size, n, "", 1);
 428
 429         return n;
 430 }
 431
 432 int chan_config_string(struct list_head *chans, char *str, int size,
 433                        char **error_out)
 434 {
 435         struct list_head *ele;
 436         struct chan *chan, *in = NULL, *out = NULL;
 437
 438         list_for_each(ele, chans) {
 439                 chan = list_entry(ele, struct chan, list);
 440                 if (!chan->primary)
 441                         continue;
 442                 if (chan->input)
 443                         in = chan;
 444                 if (chan->output)
 445                         out = chan;
 446         }
 447
 448         return chan_pair_config_string(in, out, str, size, error_out);
 449 }
 450
 451 struct chan_type {
 452         char *key;
 453         const struct chan_ops *ops;
 454 };
 455
 456 static const struct chan_type chan_table[] = {
 457         { "fd", &fd_ops },
 458
 459 #ifdef CONFIG_NULL_CHAN
 460         { "null", &null_ops },
 461 #else
 462         { "null", &not_configged_ops },
 463 #endif
 464
 465 #ifdef CONFIG_PORT_CHAN
 466         { "port", &port_ops },
 467 #else
 468         { "port", &not_configged_ops },
 469 #endif
 470
 471 #ifdef CONFIG_PTY_CHAN
 472         { "pty", &pty_ops },
 473         { "pts", &pts_ops },
 474 #else
 475         { "pty", &not_configged_ops },
 476         { "pts", &not_configged_ops },
 477 #endif
 478
 479 #ifdef CONFIG_TTY_CHAN
 480         { "tty", &tty_ops },
 481 #else
 482         { "tty", &not_configged_ops },
 483 #endif
 484
 485 #ifdef CONFIG_XTERM_CHAN
 486         { "xterm", &xterm_ops },
 487 #else
 488         { "xterm", &not_configged_ops },
 489 #endif
 490 };
 491
 492 static struct chan *parse_chan(struct line *line, char *str, int device,
 493                                const struct chan_opts *opts, char **error_out)
 494 {
 495         const struct chan_type *entry;
 496         const struct chan_ops *ops;
 497         struct chan *chan;
 498         void *data;
 499         int i;
 500
 501         ops = NULL;
 502         data = NULL;
 503         for(i = 0; i < ARRAY_SIZE(chan_table); i++) {
 504                 entry = &chan_table[i];
 505                 if (!strncmp(str, entry->key, strlen(entry->key))) {
 506                         ops = entry->ops;
 507                         str += strlen(entry->key);
 508                         break;
 509                 }
 510         }
 511         if (ops == NULL) {
 512                 *error_out = "No match for configured backends";
 513                 return NULL;
 514         }
 515
 516         data = (*ops->init)(str, device, opts);
 517         if (data == NULL) {
 518                 *error_out = "Configuration failed";
 519                 return NULL;
 520         }
 521
 522         chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
 523         if (chan == NULL) {
 524                 *error_out = "Memory allocation failed";
 525                 return NULL;
 526         }
 527         *chan = ((struct chan) { .list          = LIST_HEAD_INIT(chan->list),
 528                                  .free_list     =
 529                                         LIST_HEAD_INIT(chan->free_list),
 530                                  .line          = line,
 531                                  .primary       = 1,
 532                                  .input         = 0,
 533                                  .output        = 0,
 534                                  .opened        = 0,
 535                                  .enabled       = 0,
 536                                  .fd            = -1,
 537                                  .ops           = ops,
 538                                  .data          = data });
 539         return chan;
 540 }
 541
 542 int parse_chan_pair(char *str, struct line *line, int device,
 543                     const struct chan_opts *opts, char **error_out)
 544 {
 545         struct list_head *chans = &line->chan_list;
 546         struct chan *new, *chan;
 547         char *in, *out;
 548
 549         if (!list_empty(chans)) {
 550                 chan = list_entry(chans->next, struct chan, list);
 551                 free_chan(chans, 0);
 552                 INIT_LIST_HEAD(chans);
 553         }
 554
 555         out = strchr(str, ',');
 556         if (out != NULL) {
 557                 in = str;
 558                 *out = '\0';
 559                 out++;
 560                 new = parse_chan(line, in, device, opts, error_out);
 561                 if (new == NULL)
 562                         return -1;
 563
 564                 new->input = 1;
 565                 list_add(&new->list, chans);
 566
 567                 new = parse_chan(line, out, device, opts, error_out);
 568                 if (new == NULL)
 569                         return -1;
 570
 571                 list_add(&new->list, chans);
 572                 new->output = 1;
 573         }
 574         else {
 575                 new = parse_chan(line, str, device, opts, error_out);
 576                 if (new == NULL)
 577                         return -1;
 578
 579                 list_add(&new->list, chans);
 580                 new->input = 1;
 581                 new->output = 1;
 582         }
 583         return 0;
 584 }
 585
 586 void chan_interrupt(struct list_head *chans, struct delayed_work *task,
 587                     struct tty_struct *tty, int irq)
 588 {
 589         struct list_head *ele, *next;
 590         struct chan *chan;
 591         int err;
 592         char c;
 593
 594         list_for_each_safe(ele, next, chans) {
 595                 chan = list_entry(ele, struct chan, list);
 596                 if (!chan->input || (chan->ops->read == NULL))
 597                         continue;
 598                 do {
 599                         if (tty && !tty_buffer_request_room(tty, 1)) {
 600                                 schedule_delayed_work(task, 1);
 601                                 goto out;
 602                         }
 603                         err = chan->ops->read(chan->fd, &c, chan->data);
 604                         if (err > 0)
 605                                 tty_receive_char(tty, c);
 606                 } while (err > 0);
 607
 608                 if (err == 0)
 609                         reactivate_fd(chan->fd, irq);
 610                 if (err == -EIO) {
 611                         if (chan->primary) {
 612                                 if (tty != NULL)
 613                                         tty_hangup(tty);
 614                                 close_chan(chans, 1);
 615                                 return;
 616                         }
 617                         else close_one_chan(chan, 1);
 618                 }
 619         }
 620  out:
 621         if (tty)
 622                 tty_flip_buffer_push(tty);
 623 }