spi-topcliff-pch: add recovery processing in case wait-event timeout
[zen-stable.git] / arch / um / drivers / line.c
blobc1cf2206b84bcebb6326a48787c93f965326763b
1 /*
2 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
6 #include "linux/irqreturn.h"
7 #include "linux/kd.h"
8 #include "linux/sched.h"
9 #include "linux/slab.h"
10 #include "chan.h"
11 #include "irq_kern.h"
12 #include "irq_user.h"
13 #include "kern_util.h"
14 #include "os.h"
16 #define LINE_BUFSIZE 4096
18 static irqreturn_t line_interrupt(int irq, void *data)
20 struct chan *chan = data;
21 struct line *line = chan->line;
23 if (line)
24 chan_interrupt(&line->chan_list, &line->task, line->tty, irq);
25 return IRQ_HANDLED;
28 static void line_timer_cb(struct work_struct *work)
30 struct line *line = container_of(work, struct line, task.work);
32 if (!line->throttled)
33 chan_interrupt(&line->chan_list, &line->task, line->tty,
34 line->driver->read_irq);
38 * Returns the free space inside the ring buffer of this line.
40 * Should be called while holding line->lock (this does not modify data).
42 static int write_room(struct line *line)
44 int n;
46 if (line->buffer == NULL)
47 return LINE_BUFSIZE - 1;
49 /* This is for the case where the buffer is wrapped! */
50 n = line->head - line->tail;
52 if (n <= 0)
53 n += LINE_BUFSIZE; /* The other case */
54 return n - 1;
57 int line_write_room(struct tty_struct *tty)
59 struct line *line = tty->driver_data;
60 unsigned long flags;
61 int room;
63 spin_lock_irqsave(&line->lock, flags);
64 room = write_room(line);
65 spin_unlock_irqrestore(&line->lock, flags);
67 return room;
70 int line_chars_in_buffer(struct tty_struct *tty)
72 struct line *line = tty->driver_data;
73 unsigned long flags;
74 int ret;
76 spin_lock_irqsave(&line->lock, flags);
77 /* write_room subtracts 1 for the needed NULL, so we readd it.*/
78 ret = LINE_BUFSIZE - (write_room(line) + 1);
79 spin_unlock_irqrestore(&line->lock, flags);
81 return ret;
85 * This copies the content of buf into the circular buffer associated with
86 * this line.
87 * The return value is the number of characters actually copied, i.e. the ones
88 * for which there was space: this function is not supposed to ever flush out
89 * the circular buffer.
91 * Must be called while holding line->lock!
93 static int buffer_data(struct line *line, const char *buf, int len)
95 int end, room;
97 if (line->buffer == NULL) {
98 line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
99 if (line->buffer == NULL) {
100 printk(KERN_ERR "buffer_data - atomic allocation "
101 "failed\n");
102 return 0;
104 line->head = line->buffer;
105 line->tail = line->buffer;
108 room = write_room(line);
109 len = (len > room) ? room : len;
111 end = line->buffer + LINE_BUFSIZE - line->tail;
113 if (len < end) {
114 memcpy(line->tail, buf, len);
115 line->tail += len;
117 else {
118 /* The circular buffer is wrapping */
119 memcpy(line->tail, buf, end);
120 buf += end;
121 memcpy(line->buffer, buf, len - end);
122 line->tail = line->buffer + len - end;
125 return len;
129 * Flushes the ring buffer to the output channels. That is, write_chan is
130 * called, passing it line->head as buffer, and an appropriate count.
132 * On exit, returns 1 when the buffer is empty,
133 * 0 when the buffer is not empty on exit,
134 * and -errno when an error occurred.
136 * Must be called while holding line->lock!*/
137 static int flush_buffer(struct line *line)
139 int n, count;
141 if ((line->buffer == NULL) || (line->head == line->tail))
142 return 1;
144 if (line->tail < line->head) {
145 /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
146 count = line->buffer + LINE_BUFSIZE - line->head;
148 n = write_chan(&line->chan_list, line->head, count,
149 line->driver->write_irq);
150 if (n < 0)
151 return n;
152 if (n == count) {
154 * We have flushed from ->head to buffer end, now we
155 * must flush only from the beginning to ->tail.
157 line->head = line->buffer;
158 } else {
159 line->head += n;
160 return 0;
164 count = line->tail - line->head;
165 n = write_chan(&line->chan_list, line->head, count,
166 line->driver->write_irq);
168 if (n < 0)
169 return n;
171 line->head += n;
172 return line->head == line->tail;
175 void line_flush_buffer(struct tty_struct *tty)
177 struct line *line = tty->driver_data;
178 unsigned long flags;
180 spin_lock_irqsave(&line->lock, flags);
181 flush_buffer(line);
182 spin_unlock_irqrestore(&line->lock, flags);
186 * We map both ->flush_chars and ->put_char (which go in pair) onto
187 * ->flush_buffer and ->write. Hope it's not that bad.
189 void line_flush_chars(struct tty_struct *tty)
191 line_flush_buffer(tty);
194 int line_put_char(struct tty_struct *tty, unsigned char ch)
196 return line_write(tty, &ch, sizeof(ch));
199 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
201 struct line *line = tty->driver_data;
202 unsigned long flags;
203 int n, ret = 0;
205 spin_lock_irqsave(&line->lock, flags);
206 if (line->head != line->tail)
207 ret = buffer_data(line, buf, len);
208 else {
209 n = write_chan(&line->chan_list, buf, len,
210 line->driver->write_irq);
211 if (n < 0) {
212 ret = n;
213 goto out_up;
216 len -= n;
217 ret += n;
218 if (len > 0)
219 ret += buffer_data(line, buf + n, len);
221 out_up:
222 spin_unlock_irqrestore(&line->lock, flags);
223 return ret;
226 void line_set_termios(struct tty_struct *tty, struct ktermios * old)
228 /* nothing */
231 static const struct {
232 int cmd;
233 char *level;
234 char *name;
235 } tty_ioctls[] = {
236 /* don't print these, they flood the log ... */
237 { TCGETS, NULL, "TCGETS" },
238 { TCSETS, NULL, "TCSETS" },
239 { TCSETSW, NULL, "TCSETSW" },
240 { TCFLSH, NULL, "TCFLSH" },
241 { TCSBRK, NULL, "TCSBRK" },
243 /* general tty stuff */
244 { TCSETSF, KERN_DEBUG, "TCSETSF" },
245 { TCGETA, KERN_DEBUG, "TCGETA" },
246 { TIOCMGET, KERN_DEBUG, "TIOCMGET" },
247 { TCSBRKP, KERN_DEBUG, "TCSBRKP" },
248 { TIOCMSET, KERN_DEBUG, "TIOCMSET" },
250 /* linux-specific ones */
251 { TIOCLINUX, KERN_INFO, "TIOCLINUX" },
252 { KDGKBMODE, KERN_INFO, "KDGKBMODE" },
253 { KDGKBTYPE, KERN_INFO, "KDGKBTYPE" },
254 { KDSIGACCEPT, KERN_INFO, "KDSIGACCEPT" },
257 int line_ioctl(struct tty_struct *tty, unsigned int cmd,
258 unsigned long arg)
260 int ret;
261 int i;
263 ret = 0;
264 switch(cmd) {
265 #ifdef TIOCGETP
266 case TIOCGETP:
267 case TIOCSETP:
268 case TIOCSETN:
269 #endif
270 #ifdef TIOCGETC
271 case TIOCGETC:
272 case TIOCSETC:
273 #endif
274 #ifdef TIOCGLTC
275 case TIOCGLTC:
276 case TIOCSLTC:
277 #endif
278 /* Note: these are out of date as we now have TCGETS2 etc but this
279 whole lot should probably go away */
280 case TCGETS:
281 case TCSETSF:
282 case TCSETSW:
283 case TCSETS:
284 case TCGETA:
285 case TCSETAF:
286 case TCSETAW:
287 case TCSETA:
288 case TCXONC:
289 case TCFLSH:
290 case TIOCOUTQ:
291 case TIOCINQ:
292 case TIOCGLCKTRMIOS:
293 case TIOCSLCKTRMIOS:
294 case TIOCPKT:
295 case TIOCGSOFTCAR:
296 case TIOCSSOFTCAR:
297 return -ENOIOCTLCMD;
298 #if 0
299 case TCwhatever:
300 /* do something */
301 break;
302 #endif
303 default:
304 for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
305 if (cmd == tty_ioctls[i].cmd)
306 break;
307 if (i == ARRAY_SIZE(tty_ioctls)) {
308 printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
309 __func__, tty->name, cmd);
311 ret = -ENOIOCTLCMD;
312 break;
314 return ret;
317 void line_throttle(struct tty_struct *tty)
319 struct line *line = tty->driver_data;
321 deactivate_chan(&line->chan_list, line->driver->read_irq);
322 line->throttled = 1;
325 void line_unthrottle(struct tty_struct *tty)
327 struct line *line = tty->driver_data;
329 line->throttled = 0;
330 chan_interrupt(&line->chan_list, &line->task, tty,
331 line->driver->read_irq);
334 * Maybe there is enough stuff pending that calling the interrupt
335 * throttles us again. In this case, line->throttled will be 1
336 * again and we shouldn't turn the interrupt back on.
338 if (!line->throttled)
339 reactivate_chan(&line->chan_list, line->driver->read_irq);
342 static irqreturn_t line_write_interrupt(int irq, void *data)
344 struct chan *chan = data;
345 struct line *line = chan->line;
346 struct tty_struct *tty = line->tty;
347 int err;
350 * Interrupts are disabled here because we registered the interrupt with
351 * IRQF_DISABLED (see line_setup_irq).
354 spin_lock(&line->lock);
355 err = flush_buffer(line);
356 if (err == 0) {
357 return IRQ_NONE;
358 } else if (err < 0) {
359 line->head = line->buffer;
360 line->tail = line->buffer;
362 spin_unlock(&line->lock);
364 if (tty == NULL)
365 return IRQ_NONE;
367 tty_wakeup(tty);
368 return IRQ_HANDLED;
371 int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
373 const struct line_driver *driver = line->driver;
374 int err = 0, flags = IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM;
376 if (input)
377 err = um_request_irq(driver->read_irq, fd, IRQ_READ,
378 line_interrupt, flags,
379 driver->read_irq_name, data);
380 if (err)
381 return err;
382 if (output)
383 err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
384 line_write_interrupt, flags,
385 driver->write_irq_name, data);
386 line->have_irq = 1;
387 return err;
391 * Normally, a driver like this can rely mostly on the tty layer
392 * locking, particularly when it comes to the driver structure.
393 * However, in this case, mconsole requests can come in "from the
394 * side", and race with opens and closes.
396 * mconsole config requests will want to be sure the device isn't in
397 * use, and get_config, open, and close will want a stable
398 * configuration. The checking and modification of the configuration
399 * is done under a spinlock. Checking whether the device is in use is
400 * line->tty->count > 1, also under the spinlock.
402 * line->count serves to decide whether the device should be enabled or
403 * disabled on the host. If it's equal to 0, then we are doing the
404 * first open or last close. Otherwise, open and close just return.
407 int line_open(struct line *lines, struct tty_struct *tty)
409 struct line *line = &lines[tty->index];
410 int err = -ENODEV;
412 spin_lock(&line->count_lock);
413 if (!line->valid)
414 goto out_unlock;
416 err = 0;
417 if (line->count++)
418 goto out_unlock;
420 BUG_ON(tty->driver_data);
421 tty->driver_data = line;
422 line->tty = tty;
424 spin_unlock(&line->count_lock);
425 err = enable_chan(line);
426 if (err) /* line_close() will be called by our caller */
427 return err;
429 INIT_DELAYED_WORK(&line->task, line_timer_cb);
431 if (!line->sigio) {
432 chan_enable_winch(&line->chan_list, tty);
433 line->sigio = 1;
436 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
437 &tty->winsize.ws_col);
439 return 0;
441 out_unlock:
442 spin_unlock(&line->count_lock);
443 return err;
446 static void unregister_winch(struct tty_struct *tty);
448 void line_close(struct tty_struct *tty, struct file * filp)
450 struct line *line = tty->driver_data;
453 * If line_open fails (and tty->driver_data is never set),
454 * tty_open will call line_close. So just return in this case.
456 if (line == NULL)
457 return;
459 /* We ignore the error anyway! */
460 flush_buffer(line);
462 spin_lock(&line->count_lock);
463 BUG_ON(!line->valid);
465 if (--line->count)
466 goto out_unlock;
468 line->tty = NULL;
469 tty->driver_data = NULL;
471 spin_unlock(&line->count_lock);
473 if (line->sigio) {
474 unregister_winch(tty);
475 line->sigio = 0;
478 return;
480 out_unlock:
481 spin_unlock(&line->count_lock);
484 void close_lines(struct line *lines, int nlines)
486 int i;
488 for(i = 0; i < nlines; i++)
489 close_chan(&lines[i].chan_list, 0);
492 static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
493 char **error_out)
495 struct line *line = &lines[n];
496 int err = -EINVAL;
498 spin_lock(&line->count_lock);
500 if (line->count) {
501 *error_out = "Device is already open";
502 goto out;
505 if (line->init_pri <= init_prio) {
506 line->init_pri = init_prio;
507 if (!strcmp(init, "none"))
508 line->valid = 0;
509 else {
510 line->init_str = init;
511 line->valid = 1;
514 err = 0;
515 out:
516 spin_unlock(&line->count_lock);
517 return err;
521 * Common setup code for both startup command line and mconsole initialization.
522 * @lines contains the array (of size @num) to modify;
523 * @init is the setup string;
524 * @error_out is an error string in the case of failure;
527 int line_setup(struct line *lines, unsigned int num, char *init,
528 char **error_out)
530 int i, n, err;
531 char *end;
533 if (*init == '=') {
535 * We said con=/ssl= instead of con#=, so we are configuring all
536 * consoles at once.
538 n = -1;
540 else {
541 n = simple_strtoul(init, &end, 0);
542 if (*end != '=') {
543 *error_out = "Couldn't parse device number";
544 return -EINVAL;
546 init = end;
548 init++;
550 if (n >= (signed int) num) {
551 *error_out = "Device number out of range";
552 return -EINVAL;
554 else if (n >= 0) {
555 err = setup_one_line(lines, n, init, INIT_ONE, error_out);
556 if (err)
557 return err;
559 else {
560 for(i = 0; i < num; i++) {
561 err = setup_one_line(lines, i, init, INIT_ALL,
562 error_out);
563 if (err)
564 return err;
567 return n == -1 ? num : n;
570 int line_config(struct line *lines, unsigned int num, char *str,
571 const struct chan_opts *opts, char **error_out)
573 struct line *line;
574 char *new;
575 int n;
577 if (*str == '=') {
578 *error_out = "Can't configure all devices from mconsole";
579 return -EINVAL;
582 new = kstrdup(str, GFP_KERNEL);
583 if (new == NULL) {
584 *error_out = "Failed to allocate memory";
585 return -ENOMEM;
587 n = line_setup(lines, num, new, error_out);
588 if (n < 0)
589 return n;
591 line = &lines[n];
592 return parse_chan_pair(line->init_str, line, n, opts, error_out);
595 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
596 int size, char **error_out)
598 struct line *line;
599 char *end;
600 int dev, n = 0;
602 dev = simple_strtoul(name, &end, 0);
603 if ((*end != '\0') || (end == name)) {
604 *error_out = "line_get_config failed to parse device number";
605 return 0;
608 if ((dev < 0) || (dev >= num)) {
609 *error_out = "device number out of range";
610 return 0;
613 line = &lines[dev];
615 spin_lock(&line->count_lock);
616 if (!line->valid)
617 CONFIG_CHUNK(str, size, n, "none", 1);
618 else if (line->tty == NULL)
619 CONFIG_CHUNK(str, size, n, line->init_str, 1);
620 else n = chan_config_string(&line->chan_list, str, size, error_out);
621 spin_unlock(&line->count_lock);
623 return n;
626 int line_id(char **str, int *start_out, int *end_out)
628 char *end;
629 int n;
631 n = simple_strtoul(*str, &end, 0);
632 if ((*end != '\0') || (end == *str))
633 return -1;
635 *str = end;
636 *start_out = n;
637 *end_out = n;
638 return n;
641 int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
643 int err;
644 char config[sizeof("conxxxx=none\0")];
646 sprintf(config, "%d=none", n);
647 err = line_setup(lines, num, config, error_out);
648 if (err >= 0)
649 err = 0;
650 return err;
653 struct tty_driver *register_lines(struct line_driver *line_driver,
654 const struct tty_operations *ops,
655 struct line *lines, int nlines)
657 int i;
658 struct tty_driver *driver = alloc_tty_driver(nlines);
660 if (!driver)
661 return NULL;
663 driver->driver_name = line_driver->name;
664 driver->name = line_driver->device_name;
665 driver->major = line_driver->major;
666 driver->minor_start = line_driver->minor_start;
667 driver->type = line_driver->type;
668 driver->subtype = line_driver->subtype;
669 driver->flags = TTY_DRIVER_REAL_RAW;
670 driver->init_termios = tty_std_termios;
671 tty_set_operations(driver, ops);
673 if (tty_register_driver(driver)) {
674 printk(KERN_ERR "register_lines : can't register %s driver\n",
675 line_driver->name);
676 put_tty_driver(driver);
677 return NULL;
680 for(i = 0; i < nlines; i++) {
681 if (!lines[i].valid)
682 tty_unregister_device(driver, i);
685 mconsole_register_dev(&line_driver->mc);
686 return driver;
689 static DEFINE_SPINLOCK(winch_handler_lock);
690 static LIST_HEAD(winch_handlers);
692 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
694 struct line *line;
695 char *error;
696 int i;
698 for(i = 0; i < nlines; i++) {
699 line = &lines[i];
700 INIT_LIST_HEAD(&line->chan_list);
702 if (line->init_str == NULL)
703 continue;
705 line->init_str = kstrdup(line->init_str, GFP_KERNEL);
706 if (line->init_str == NULL)
707 printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
709 if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
710 printk(KERN_ERR "parse_chan_pair failed for "
711 "device %d : %s\n", i, error);
712 line->valid = 0;
717 struct winch {
718 struct list_head list;
719 int fd;
720 int tty_fd;
721 int pid;
722 struct tty_struct *tty;
723 unsigned long stack;
724 struct work_struct work;
727 static void __free_winch(struct work_struct *work)
729 struct winch *winch = container_of(work, struct winch, work);
730 free_irq(WINCH_IRQ, winch);
732 if (winch->pid != -1)
733 os_kill_process(winch->pid, 1);
734 if (winch->stack != 0)
735 free_stack(winch->stack, 0);
736 kfree(winch);
739 static void free_winch(struct winch *winch)
741 int fd = winch->fd;
742 winch->fd = -1;
743 if (fd != -1)
744 os_close_file(fd);
745 list_del(&winch->list);
746 __free_winch(&winch->work);
749 static irqreturn_t winch_interrupt(int irq, void *data)
751 struct winch *winch = data;
752 struct tty_struct *tty;
753 struct line *line;
754 int fd = winch->fd;
755 int err;
756 char c;
758 if (fd != -1) {
759 err = generic_read(fd, &c, NULL);
760 if (err < 0) {
761 if (err != -EAGAIN) {
762 winch->fd = -1;
763 list_del(&winch->list);
764 os_close_file(fd);
765 printk(KERN_ERR "winch_interrupt : "
766 "read failed, errno = %d\n", -err);
767 printk(KERN_ERR "fd %d is losing SIGWINCH "
768 "support\n", winch->tty_fd);
769 INIT_WORK(&winch->work, __free_winch);
770 schedule_work(&winch->work);
771 return IRQ_HANDLED;
773 goto out;
776 tty = winch->tty;
777 if (tty != NULL) {
778 line = tty->driver_data;
779 if (line != NULL) {
780 chan_window_size(&line->chan_list, &tty->winsize.ws_row,
781 &tty->winsize.ws_col);
782 kill_pgrp(tty->pgrp, SIGWINCH, 1);
785 out:
786 if (winch->fd != -1)
787 reactivate_fd(winch->fd, WINCH_IRQ);
788 return IRQ_HANDLED;
791 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
792 unsigned long stack)
794 struct winch *winch;
796 winch = kmalloc(sizeof(*winch), GFP_KERNEL);
797 if (winch == NULL) {
798 printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
799 goto cleanup;
802 *winch = ((struct winch) { .list = LIST_HEAD_INIT(winch->list),
803 .fd = fd,
804 .tty_fd = tty_fd,
805 .pid = pid,
806 .tty = tty,
807 .stack = stack });
809 if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
810 IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
811 "winch", winch) < 0) {
812 printk(KERN_ERR "register_winch_irq - failed to register "
813 "IRQ\n");
814 goto out_free;
817 spin_lock(&winch_handler_lock);
818 list_add(&winch->list, &winch_handlers);
819 spin_unlock(&winch_handler_lock);
821 return;
823 out_free:
824 kfree(winch);
825 cleanup:
826 os_kill_process(pid, 1);
827 os_close_file(fd);
828 if (stack != 0)
829 free_stack(stack, 0);
832 static void unregister_winch(struct tty_struct *tty)
834 struct list_head *ele, *next;
835 struct winch *winch;
837 spin_lock(&winch_handler_lock);
839 list_for_each_safe(ele, next, &winch_handlers) {
840 winch = list_entry(ele, struct winch, list);
841 if (winch->tty == tty) {
842 free_winch(winch);
843 break;
846 spin_unlock(&winch_handler_lock);
849 static void winch_cleanup(void)
851 struct list_head *ele, *next;
852 struct winch *winch;
854 spin_lock(&winch_handler_lock);
856 list_for_each_safe(ele, next, &winch_handlers) {
857 winch = list_entry(ele, struct winch, list);
858 free_winch(winch);
861 spin_unlock(&winch_handler_lock);
863 __uml_exitcall(winch_cleanup);
865 char *add_xterm_umid(char *base)
867 char *umid, *title;
868 int len;
870 umid = get_umid();
871 if (*umid == '\0')
872 return base;
874 len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
875 title = kmalloc(len, GFP_KERNEL);
876 if (title == NULL) {
877 printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
878 return base;
881 snprintf(title, len, "%s (%s)", base, umid);
882 return title;