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