arch/um/drivers/chan_kern.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
   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, u8 *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 u8 *buf, size_t 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->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->read_irq, chan);
 199                 if (chan->output && chan->enabled)
 200                         um_free_irq(chan->line->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->read_irq, chan);
 219                 if (chan->output && chan->enabled)
 220                         um_free_irq(chan->line->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 int write_chan(struct chan *chan, const u8 *buf, size_t len, int write_irq)
 251 {
 252         int n, ret = 0;
 253
 254         if (len == 0 || !chan || !chan->ops->write)
 255                 return 0;
 256
 257         n = chan->ops->write(chan->fd, buf, len, chan->data);
 258         if (chan->primary) {
 259                 ret = n;
 260         }
 261         return ret;
 262 }
 263
 264 int console_write_chan(struct chan *chan, const char *buf, int len)
 265 {
 266         int n, ret = 0;
 267
 268         if (!chan || !chan->ops->console_write)
 269                 return 0;
 270
 271         n = chan->ops->console_write(chan->fd, buf, len);
 272         if (chan->primary)
 273                 ret = n;
 274         return ret;
 275 }
 276
 277 int console_open_chan(struct line *line, struct console *co)
 278 {
 279         int err;
 280
 281         err = open_chan(&line->chan_list);
 282         if (err)
 283                 return err;
 284
 285         printk(KERN_INFO "Console initialized on /dev/%s%d\n", co->name,
 286                co->index);
 287         return 0;
 288 }
 289
 290 int chan_window_size(struct line *line, unsigned short *rows_out,
 291                       unsigned short *cols_out)
 292 {
 293         struct chan *chan;
 294
 295         chan = line->chan_in;
 296         if (chan && chan->primary) {
 297                 if (chan->ops->window_size == NULL)
 298                         return 0;
 299                 return chan->ops->window_size(chan->fd, chan->data,
 300                                               rows_out, cols_out);
 301         }
 302         chan = line->chan_out;
 303         if (chan && chan->primary) {
 304                 if (chan->ops->window_size == NULL)
 305                         return 0;
 306                 return chan->ops->window_size(chan->fd, chan->data,
 307                                               rows_out, cols_out);
 308         }
 309         return 0;
 310 }
 311
 312 static void free_one_chan(struct chan *chan)
 313 {
 314         list_del(&chan->list);
 315
 316         close_one_chan(chan, 0);
 317
 318         if (chan->ops->free != NULL)
 319                 (*chan->ops->free)(chan->data);
 320
 321         if (chan->primary && chan->output)
 322                 ignore_sigio_fd(chan->fd);
 323         kfree(chan);
 324 }
 325
 326 static void free_chan(struct list_head *chans)
 327 {
 328         struct list_head *ele, *next;
 329         struct chan *chan;
 330
 331         list_for_each_safe(ele, next, chans) {
 332                 chan = list_entry(ele, struct chan, list);
 333                 free_one_chan(chan);
 334         }
 335 }
 336
 337 static int one_chan_config_string(struct chan *chan, char *str, int size,
 338                                   char **error_out)
 339 {
 340         int n = 0;
 341
 342         if (chan == NULL) {
 343                 CONFIG_CHUNK(str, size, n, "none", 1);
 344                 return n;
 345         }
 346
 347         CONFIG_CHUNK(str, size, n, chan->ops->type, 0);
 348
 349         if (chan->dev == NULL) {
 350                 CONFIG_CHUNK(str, size, n, "", 1);
 351                 return n;
 352         }
 353
 354         CONFIG_CHUNK(str, size, n, ":", 0);
 355         CONFIG_CHUNK(str, size, n, chan->dev, 0);
 356
 357         return n;
 358 }
 359
 360 static int chan_pair_config_string(struct chan *in, struct chan *out,
 361                                    char *str, int size, char **error_out)
 362 {
 363         int n;
 364
 365         n = one_chan_config_string(in, str, size, error_out);
 366         str += n;
 367         size -= n;
 368
 369         if (in == out) {
 370                 CONFIG_CHUNK(str, size, n, "", 1);
 371                 return n;
 372         }
 373
 374         CONFIG_CHUNK(str, size, n, ",", 1);
 375         n = one_chan_config_string(out, str, size, error_out);
 376         str += n;
 377         size -= n;
 378         CONFIG_CHUNK(str, size, n, "", 1);
 379
 380         return n;
 381 }
 382
 383 int chan_config_string(struct line *line, char *str, int size,
 384                        char **error_out)
 385 {
 386         struct chan *in = line->chan_in, *out = line->chan_out;
 387
 388         if (in && !in->primary)
 389                 in = NULL;
 390         if (out && !out->primary)
 391                 out = NULL;
 392
 393         return chan_pair_config_string(in, out, str, size, error_out);
 394 }
 395
 396 struct chan_type {
 397         char *key;
 398         const struct chan_ops *ops;
 399 };
 400
 401 static const struct chan_type chan_table[] = {
 402         { "fd", &fd_ops },
 403
 404 #ifdef CONFIG_NULL_CHAN
 405         { "null", &null_ops },
 406 #else
 407         { "null", &not_configged_ops },
 408 #endif
 409
 410 #ifdef CONFIG_PORT_CHAN
 411         { "port", &port_ops },
 412 #else
 413         { "port", &not_configged_ops },
 414 #endif
 415
 416 #ifdef CONFIG_PTY_CHAN
 417         { "pty", &pty_ops },
 418         { "pts", &pts_ops },
 419 #else
 420         { "pty", &not_configged_ops },
 421         { "pts", &not_configged_ops },
 422 #endif
 423
 424 #ifdef CONFIG_TTY_CHAN
 425         { "tty", &tty_ops },
 426 #else
 427         { "tty", &not_configged_ops },
 428 #endif
 429
 430 #ifdef CONFIG_XTERM_CHAN
 431         { "xterm", &xterm_ops },
 432 #else
 433         { "xterm", &not_configged_ops },
 434 #endif
 435 };
 436
 437 static struct chan *parse_chan(struct line *line, char *str, int device,
 438                                const struct chan_opts *opts, char **error_out)
 439 {
 440         const struct chan_type *entry;
 441         const struct chan_ops *ops;
 442         struct chan *chan;
 443         void *data;
 444         int i;
 445
 446         ops = NULL;
 447         data = NULL;
 448         for(i = 0; i < ARRAY_SIZE(chan_table); i++) {
 449                 entry = &chan_table[i];
 450                 if (!strncmp(str, entry->key, strlen(entry->key))) {
 451                         ops = entry->ops;
 452                         str += strlen(entry->key);
 453                         break;
 454                 }
 455         }
 456         if (ops == NULL) {
 457                 *error_out = "No match for configured backends";
 458                 return NULL;
 459         }
 460
 461         data = (*ops->init)(str, device, opts);
 462         if (data == NULL) {
 463                 *error_out = "Configuration failed";
 464                 return NULL;
 465         }
 466
 467         chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
 468         if (chan == NULL) {
 469                 *error_out = "Memory allocation failed";
 470                 return NULL;
 471         }
 472         *chan = ((struct chan) { .list          = LIST_HEAD_INIT(chan->list),
 473                                  .free_list     =
 474                                         LIST_HEAD_INIT(chan->free_list),
 475                                  .line          = line,
 476                                  .primary       = 1,
 477                                  .input         = 0,
 478                                  .output        = 0,
 479                                  .opened        = 0,
 480                                  .enabled       = 0,
 481                                  .fd            = -1,
 482                                  .ops           = ops,
 483                                  .data          = data });
 484         return chan;
 485 }
 486
 487 int parse_chan_pair(char *str, struct line *line, int device,
 488                     const struct chan_opts *opts, char **error_out)
 489 {
 490         struct list_head *chans = &line->chan_list;
 491         struct chan *new;
 492         char *in, *out;
 493
 494         if (!list_empty(chans)) {
 495                 line->chan_in = line->chan_out = NULL;
 496                 free_chan(chans);
 497                 INIT_LIST_HEAD(chans);
 498         }
 499
 500         if (!str)
 501                 return 0;
 502
 503         out = strchr(str, ',');
 504         if (out != NULL) {
 505                 in = str;
 506                 *out = '\0';
 507                 out++;
 508                 new = parse_chan(line, in, device, opts, error_out);
 509                 if (new == NULL)
 510                         return -1;
 511
 512                 new->input = 1;
 513                 list_add(&new->list, chans);
 514                 line->chan_in = new;
 515
 516                 new = parse_chan(line, out, device, opts, error_out);
 517                 if (new == NULL)
 518                         return -1;
 519
 520                 list_add(&new->list, chans);
 521                 new->output = 1;
 522                 line->chan_out = new;
 523         }
 524         else {
 525                 new = parse_chan(line, str, device, opts, error_out);
 526                 if (new == NULL)
 527                         return -1;
 528
 529                 list_add(&new->list, chans);
 530                 new->input = 1;
 531                 new->output = 1;
 532                 line->chan_in = line->chan_out = new;
 533         }
 534         return 0;
 535 }
 536
 537 void chan_interrupt(struct line *line, int irq)
 538 {
 539         struct tty_port *port = &line->port;
 540         struct chan *chan = line->chan_in;
 541         int err;
 542         u8 c;
 543
 544         if (!chan || !chan->ops->read)
 545                 goto out;
 546
 547         do {
 548                 if (!tty_buffer_request_room(port, 1)) {
 549                         schedule_delayed_work(&line->task, 1);
 550                         goto out;
 551                 }
 552                 err = chan->ops->read(chan->fd, &c, chan->data);
 553                 if (err > 0)
 554                         tty_insert_flip_char(port, c, TTY_NORMAL);
 555         } while (err > 0);
 556
 557         if (err == -EIO) {
 558                 if (chan->primary) {
 559                         tty_port_tty_hangup(&line->port, false);
 560                         if (line->chan_out != chan)
 561                                 close_one_chan(line->chan_out, 1);
 562                 }
 563                 close_one_chan(chan, 1);
 564                 if (chan->primary)
 565                         return;
 566         }
 567  out:
 568         tty_flip_buffer_push(port);
 569 }