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