blob: 2b6a56b2bf35c78b53153d87b032c720b5b0b004 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
3 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
4 * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
5 * Copyright (C) 2004 IBM Corporation
6 *
7 * Additional Author(s):
8 * Ryan S. Arnold <rsa@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 */
24
Milton Millere51d8c92005-07-07 17:56:21 -070025#include <linux/config.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/console.h>
27#include <linux/cpumask.h>
28#include <linux/init.h>
29#include <linux/kbd_kern.h>
30#include <linux/kernel.h>
31#include <linux/kobject.h>
32#include <linux/kthread.h>
33#include <linux/list.h>
34#include <linux/module.h>
35#include <linux/major.h>
36#include <linux/sysrq.h>
37#include <linux/tty.h>
38#include <linux/tty_flip.h>
39#include <linux/sched.h>
40#include <linux/spinlock.h>
41#include <linux/delay.h>
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020042
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <asm/uaccess.h>
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020044
45#include "hvc_console.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
47#define HVC_MAJOR 229
48#define HVC_MINOR 0
49
50#define TIMEOUT (10)
51
52/*
53 * Wait this long per iteration while trying to push buffered data to the
54 * hypervisor before allowing the tty to complete a close operation.
55 */
56#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
57
58/*
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020059 * These sizes are most efficient for vio, because they are the
60 * native transfer size. We could make them selectable in the
61 * future to better deal with backends that want other buffer sizes.
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070063#define N_OUTBUF 16
64#define N_INBUF 16
65
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020066#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
Milton Miller837dcfa2005-07-07 17:56:16 -070068static struct tty_driver *hvc_driver;
69static struct task_struct *hvc_task;
70
71/* Picks up late kicks after list walk but before schedule() */
72static int hvc_kicked;
73
74#ifdef CONFIG_MAGIC_SYSRQ
75static int sysrq_pressed;
76#endif
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078struct hvc_struct {
79 spinlock_t lock;
80 int index;
81 struct tty_struct *tty;
82 unsigned int count;
83 int do_wakeup;
84 char outbuf[N_OUTBUF] __ALIGNED__;
85 int n_outbuf;
86 uint32_t vtermno;
Milton Miller030ffad2005-07-07 17:56:25 -070087 struct hv_ops *ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 int irq_requested;
89 int irq;
90 struct list_head next;
91 struct kobject kobj; /* ref count & hvc_struct lifetime */
Linus Torvalds1da177e2005-04-16 15:20:36 -070092};
93
94/* dynamic list of hvc_struct instances */
95static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs);
96
97/*
98 * Protect the list of hvc_struct instances from inserts and removals during
99 * list traversal.
100 */
101static DEFINE_SPINLOCK(hvc_structs_lock);
102
103/*
Milton Miller6f248082005-07-07 17:56:17 -0700104 * This value is used to assign a tty->index value to a hvc_struct based
105 * upon order of exposure via hvc_probe(), when we can not match it to
106 * a console canidate registered with hvc_instantiate().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 */
Milton Miller6f248082005-07-07 17:56:17 -0700108static int last_hvc = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110/*
111 * Do not call this function with either the hvc_strucst_lock or the hvc_struct
112 * lock held. If successful, this function increments the kobject reference
113 * count against the target hvc_struct so it should be released when finished.
114 */
115struct hvc_struct *hvc_get_by_index(int index)
116{
117 struct hvc_struct *hp;
118 unsigned long flags;
119
120 spin_lock(&hvc_structs_lock);
121
122 list_for_each_entry(hp, &hvc_structs, next) {
123 spin_lock_irqsave(&hp->lock, flags);
124 if (hp->index == index) {
125 kobject_get(&hp->kobj);
126 spin_unlock_irqrestore(&hp->lock, flags);
127 spin_unlock(&hvc_structs_lock);
128 return hp;
129 }
130 spin_unlock_irqrestore(&hp->lock, flags);
131 }
132 hp = NULL;
133
134 spin_unlock(&hvc_structs_lock);
135 return hp;
136}
137
Milton Miller837dcfa2005-07-07 17:56:16 -0700138
139/*
140 * Initial console vtermnos for console API usage prior to full console
141 * initialization. Any vty adapter outside this range will not have usable
142 * console interfaces but can still be used as a tty device. This has to be
143 * static because kmalloc will not work during early console init.
144 */
Milton Miller030ffad2005-07-07 17:56:25 -0700145static struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
Milton Miller64e4da52005-07-07 17:56:22 -0700146static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
147 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
Milton Miller837dcfa2005-07-07 17:56:16 -0700148
149/*
150 * Console APIs, NOT TTY. These APIs are available immediately when
151 * hvc_console_setup() finds adapters.
152 */
153
154void hvc_console_print(struct console *co, const char *b, unsigned count)
155{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200156 char c[N_OUTBUF] __ALIGNED__;
Milton Miller837dcfa2005-07-07 17:56:16 -0700157 unsigned i = 0, n = 0;
Milton Miller030ffad2005-07-07 17:56:25 -0700158 int r, donecr = 0, index = co->index;
Milton Miller837dcfa2005-07-07 17:56:16 -0700159
160 /* Console access attempt outside of acceptable console range. */
Milton Miller030ffad2005-07-07 17:56:25 -0700161 if (index >= MAX_NR_HVC_CONSOLES)
Milton Miller837dcfa2005-07-07 17:56:16 -0700162 return;
163
164 /* This console adapter was removed so it is not useable. */
Milton Miller030ffad2005-07-07 17:56:25 -0700165 if (vtermnos[index] < 0)
Milton Miller837dcfa2005-07-07 17:56:16 -0700166 return;
167
168 while (count > 0 || i > 0) {
169 if (count > 0 && i < sizeof(c)) {
170 if (b[n] == '\n' && !donecr) {
171 c[i++] = '\r';
172 donecr = 1;
173 } else {
174 c[i++] = b[n++];
175 donecr = 0;
176 --count;
177 }
178 } else {
Milton Miller030ffad2005-07-07 17:56:25 -0700179 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
Milton Miller837dcfa2005-07-07 17:56:16 -0700180 if (r < 0) {
181 /* throw away chars on error */
182 i = 0;
183 } else if (r > 0) {
184 i -= r;
185 if (i > 0)
186 memmove(c, c+r, i);
187 }
188 }
189 }
190}
191
192static struct tty_driver *hvc_console_device(struct console *c, int *index)
193{
Milton Miller7805b1b2005-07-07 17:56:23 -0700194 if (vtermnos[c->index] == -1)
195 return NULL;
196
Milton Miller837dcfa2005-07-07 17:56:16 -0700197 *index = c->index;
198 return hvc_driver;
199}
200
201static int __init hvc_console_setup(struct console *co, char *options)
202{
Milton Miller7805b1b2005-07-07 17:56:23 -0700203 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
204 return -ENODEV;
205
206 if (vtermnos[co->index] == -1)
207 return -ENODEV;
208
Milton Miller837dcfa2005-07-07 17:56:16 -0700209 return 0;
210}
211
212struct console hvc_con_driver = {
213 .name = "hvc",
214 .write = hvc_console_print,
215 .device = hvc_console_device,
216 .setup = hvc_console_setup,
217 .flags = CON_PRINTBUFFER,
218 .index = -1,
219};
220
Milton Millerd5ee2572005-07-07 17:56:24 -0700221/*
222 * Early console initialization. Preceeds driver initialization.
223 *
224 * (1) we are first, and the user specified another driver
225 * -- index will remain -1
226 * (2) we are first and the user specified no driver
227 * -- index will be set to 0, then we will fail setup.
228 * (3) we are first and the user specified our driver
229 * -- index will be set to user specified driver, and we will fail
230 * (4) we are after driver, and this initcall will register us
231 * -- if the user didn't specify a driver then the console will match
232 *
233 * Note that for cases 2 and 3, we will match later when the io driver
234 * calls hvc_instantiate() and call register again.
235 */
Milton Miller837dcfa2005-07-07 17:56:16 -0700236static int __init hvc_console_init(void)
237{
Milton Miller837dcfa2005-07-07 17:56:16 -0700238 register_console(&hvc_con_driver);
239 return 0;
240}
241console_initcall(hvc_console_init);
242
243/*
Milton Miller6f248082005-07-07 17:56:17 -0700244 * hvc_instantiate() is an early console discovery method which locates
245 * consoles * prior to the vio subsystem discovering them. Hotplugged
246 * vty adapters do NOT get an hvc_instantiate() callback since they
247 * appear after early console init.
Milton Miller837dcfa2005-07-07 17:56:16 -0700248 */
Milton Miller030ffad2005-07-07 17:56:25 -0700249int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops)
Milton Miller837dcfa2005-07-07 17:56:16 -0700250{
Milton Miller7805b1b2005-07-07 17:56:23 -0700251 struct hvc_struct *hp;
252
Milton Miller837dcfa2005-07-07 17:56:16 -0700253 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
254 return -1;
255
256 if (vtermnos[index] != -1)
257 return -1;
258
Milton Miller7805b1b2005-07-07 17:56:23 -0700259 /* make sure no no tty has been registerd in this index */
260 hp = hvc_get_by_index(index);
261 if (hp) {
262 kobject_put(&hp->kobj);
263 return -1;
264 }
265
Milton Miller837dcfa2005-07-07 17:56:16 -0700266 vtermnos[index] = vtermno;
Milton Miller030ffad2005-07-07 17:56:25 -0700267 cons_ops[index] = ops;
Milton Miller6f248082005-07-07 17:56:17 -0700268
269 /* reserve all indices upto and including this index */
270 if (last_hvc < index)
271 last_hvc = index;
272
Milton Millerd5ee2572005-07-07 17:56:24 -0700273 /* if this index is what the user requested, then register
274 * now (setup won't fail at this point). It's ok to just
275 * call register again if previously .setup failed.
276 */
277 if (index == hvc_con_driver.index)
278 register_console(&hvc_con_driver);
279
Milton Miller837dcfa2005-07-07 17:56:16 -0700280 return 0;
281}
Milton Milleracad9552005-07-07 17:56:24 -0700282EXPORT_SYMBOL(hvc_instantiate);
Milton Miller837dcfa2005-07-07 17:56:16 -0700283
284/* Wake the sleeping khvcd */
285static void hvc_kick(void)
286{
287 hvc_kicked = 1;
288 wake_up_process(hvc_task);
289}
290
Milton Miller8b67f8c2005-07-07 17:56:18 -0700291static int hvc_poll(struct hvc_struct *hp);
292
Milton Miller837dcfa2005-07-07 17:56:16 -0700293/*
294 * NOTE: This API isn't used if the console adapter doesn't support interrupts.
295 * In this case the console is poll driven.
296 */
297static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
298{
Milton Miller8b67f8c2005-07-07 17:56:18 -0700299 /* if hvc_poll request a repoll, then kick the hvcd thread */
300 if (hvc_poll(dev_instance))
301 hvc_kick();
Milton Miller837dcfa2005-07-07 17:56:16 -0700302 return IRQ_HANDLED;
303}
304
305static void hvc_unthrottle(struct tty_struct *tty)
306{
307 hvc_kick();
308}
309
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310/*
311 * The TTY interface won't be used until after the vio layer has exposed the vty
312 * adapter to the kernel.
313 */
314static int hvc_open(struct tty_struct *tty, struct file * filp)
315{
316 struct hvc_struct *hp;
317 unsigned long flags;
318 int irq = NO_IRQ;
319 int rc = 0;
320 struct kobject *kobjp;
321
322 /* Auto increments kobject reference if found. */
323 if (!(hp = hvc_get_by_index(tty->index))) {
324 printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n");
325 return -ENODEV;
326 }
327
328 spin_lock_irqsave(&hp->lock, flags);
329 /* Check and then increment for fast path open. */
330 if (hp->count++ > 0) {
331 spin_unlock_irqrestore(&hp->lock, flags);
332 hvc_kick();
333 return 0;
334 } /* else count == 0 */
335
336 tty->driver_data = hp;
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500337 tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */
338
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 hp->tty = tty;
340 /* Save for request_irq outside of spin_lock. */
341 irq = hp->irq;
342 if (irq != NO_IRQ)
343 hp->irq_requested = 1;
344
345 kobjp = &hp->kobj;
346
347 spin_unlock_irqrestore(&hp->lock, flags);
348 /* check error, fallback to non-irq */
349 if (irq != NO_IRQ)
350 rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp);
351
352 /*
353 * If the request_irq() fails and we return an error. The tty layer
354 * will call hvc_close() after a failed open but we don't want to clean
355 * up there so we'll clean up here and clear out the previously set
356 * tty fields and return the kobject reference.
357 */
358 if (rc) {
359 spin_lock_irqsave(&hp->lock, flags);
360 hp->tty = NULL;
361 hp->irq_requested = 0;
362 spin_unlock_irqrestore(&hp->lock, flags);
363 tty->driver_data = NULL;
364 kobject_put(kobjp);
365 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
366 }
367 /* Force wakeup of the polling thread */
368 hvc_kick();
369
370 return rc;
371}
372
373static void hvc_close(struct tty_struct *tty, struct file * filp)
374{
375 struct hvc_struct *hp;
376 struct kobject *kobjp;
377 int irq = NO_IRQ;
378 unsigned long flags;
379
380 if (tty_hung_up_p(filp))
381 return;
382
383 /*
384 * No driver_data means that this close was issued after a failed
385 * hvc_open by the tty layer's release_dev() function and we can just
386 * exit cleanly because the kobject reference wasn't made.
387 */
388 if (!tty->driver_data)
389 return;
390
391 hp = tty->driver_data;
392 spin_lock_irqsave(&hp->lock, flags);
393
394 kobjp = &hp->kobj;
395 if (--hp->count == 0) {
396 if (hp->irq_requested)
397 irq = hp->irq;
398 hp->irq_requested = 0;
399
400 /* We are done with the tty pointer now. */
401 hp->tty = NULL;
402 spin_unlock_irqrestore(&hp->lock, flags);
403
404 /*
405 * Chain calls chars_in_buffer() and returns immediately if
406 * there is no buffered data otherwise sleeps on a wait queue
407 * waking periodically to check chars_in_buffer().
408 */
409 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
410
411 if (irq != NO_IRQ)
412 free_irq(irq, hp);
413
414 } else {
415 if (hp->count < 0)
416 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
417 hp->vtermno, hp->count);
418 spin_unlock_irqrestore(&hp->lock, flags);
419 }
420
421 kobject_put(kobjp);
422}
423
424static void hvc_hangup(struct tty_struct *tty)
425{
426 struct hvc_struct *hp = tty->driver_data;
427 unsigned long flags;
428 int irq = NO_IRQ;
429 int temp_open_count;
430 struct kobject *kobjp;
431
432 if (!hp)
433 return;
434
435 spin_lock_irqsave(&hp->lock, flags);
436
437 /*
438 * The N_TTY line discipline has problems such that in a close vs
439 * open->hangup case this can be called after the final close so prevent
440 * that from happening for now.
441 */
442 if (hp->count <= 0) {
443 spin_unlock_irqrestore(&hp->lock, flags);
444 return;
445 }
446
447 kobjp = &hp->kobj;
448 temp_open_count = hp->count;
449 hp->count = 0;
450 hp->n_outbuf = 0;
451 hp->tty = NULL;
452 if (hp->irq_requested)
453 /* Saved for use outside of spin_lock. */
454 irq = hp->irq;
455 hp->irq_requested = 0;
456 spin_unlock_irqrestore(&hp->lock, flags);
457 if (irq != NO_IRQ)
458 free_irq(irq, hp);
459 while(temp_open_count) {
460 --temp_open_count;
461 kobject_put(kobjp);
462 }
463}
464
465/*
466 * Push buffered characters whether they were just recently buffered or waiting
467 * on a blocked hypervisor. Call this function with hp->lock held.
468 */
469static void hvc_push(struct hvc_struct *hp)
470{
471 int n;
472
Milton Miller030ffad2005-07-07 17:56:25 -0700473 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 if (n <= 0) {
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200475 if (n == 0) {
476 hp->do_wakeup = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 return;
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200478 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 /* throw away output on error; this happens when
480 there is no session connected to the vterm. */
481 hp->n_outbuf = 0;
482 } else
483 hp->n_outbuf -= n;
484 if (hp->n_outbuf > 0)
485 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
486 else
487 hp->do_wakeup = 1;
488}
489
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200490static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200492 struct hvc_struct *hp = tty->driver_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 unsigned long flags;
494 int rsize, written = 0;
495
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200496 /* This write was probably executed during a tty close. */
497 if (!hp)
498 return -EPIPE;
499
500 if (hp->count <= 0)
501 return -EIO;
502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 spin_lock_irqsave(&hp->lock, flags);
504
505 /* Push pending writes */
506 if (hp->n_outbuf > 0)
507 hvc_push(hp);
508
509 while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) {
510 if (rsize > count)
511 rsize = count;
512 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
513 count -= rsize;
514 buf += rsize;
515 hp->n_outbuf += rsize;
516 written += rsize;
517 hvc_push(hp);
518 }
519 spin_unlock_irqrestore(&hp->lock, flags);
520
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 /*
522 * Racy, but harmless, kick thread if there is still pending data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 */
524 if (hp->n_outbuf)
525 hvc_kick();
526
527 return written;
528}
529
530/*
531 * This is actually a contract between the driver and the tty layer outlining
532 * how much write room the driver can guarentee will be sent OR BUFFERED. This
533 * driver MUST honor the return value.
534 */
535static int hvc_write_room(struct tty_struct *tty)
536{
537 struct hvc_struct *hp = tty->driver_data;
538
539 if (!hp)
540 return -1;
541
542 return N_OUTBUF - hp->n_outbuf;
543}
544
545static int hvc_chars_in_buffer(struct tty_struct *tty)
546{
547 struct hvc_struct *hp = tty->driver_data;
548
549 if (!hp)
550 return -1;
551 return hp->n_outbuf;
552}
553
554#define HVC_POLL_READ 0x00000001
555#define HVC_POLL_WRITE 0x00000002
556#define HVC_POLL_QUICK 0x00000004
557
558static int hvc_poll(struct hvc_struct *hp)
559{
560 struct tty_struct *tty;
561 int i, n, poll_mask = 0;
562 char buf[N_INBUF] __ALIGNED__;
563 unsigned long flags;
564 int read_total = 0;
565
566 spin_lock_irqsave(&hp->lock, flags);
567
568 /* Push pending writes */
569 if (hp->n_outbuf > 0)
570 hvc_push(hp);
571 /* Reschedule us if still some write pending */
572 if (hp->n_outbuf > 0)
573 poll_mask |= HVC_POLL_WRITE;
574
575 /* No tty attached, just skip */
576 tty = hp->tty;
577 if (tty == NULL)
578 goto bail;
579
580 /* Now check if we can get data (are we throttled ?) */
581 if (test_bit(TTY_THROTTLED, &tty->flags))
582 goto throttled;
583
584 /* If we aren't interrupt driven and aren't throttled, we always
585 * request a reschedule
586 */
587 if (hp->irq == NO_IRQ)
588 poll_mask |= HVC_POLL_READ;
589
590 /* Read data if any */
591 for (;;) {
Alan Cox33f0f882006-01-09 20:54:13 -0800592 int count = tty_buffer_request_room(tty, N_INBUF);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
594 /* If flip is full, just reschedule a later read */
595 if (count == 0) {
596 poll_mask |= HVC_POLL_READ;
597 break;
598 }
599
Milton Miller030ffad2005-07-07 17:56:25 -0700600 n = hp->ops->get_chars(hp->vtermno, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 if (n <= 0) {
602 /* Hangup the tty when disconnected from host */
603 if (n == -EPIPE) {
604 spin_unlock_irqrestore(&hp->lock, flags);
605 tty_hangup(tty);
606 spin_lock_irqsave(&hp->lock, flags);
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200607 } else if ( n == -EAGAIN ) {
608 /*
609 * Some back-ends can only ensure a certain min
610 * num of bytes read, which may be > 'count'.
611 * Let the tty clear the flip buff to make room.
612 */
613 poll_mask |= HVC_POLL_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 }
615 break;
616 }
617 for (i = 0; i < n; ++i) {
618#ifdef CONFIG_MAGIC_SYSRQ
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700619 if (hp->index == hvc_con_driver.index) {
620 /* Handle the SysRq Hack */
621 /* XXX should support a sequence */
622 if (buf[i] == '\x0f') { /* ^O */
623 sysrq_pressed = 1;
624 continue;
625 } else if (sysrq_pressed) {
626 handle_sysrq(buf[i], NULL, tty);
627 sysrq_pressed = 0;
628 continue;
629 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 }
631#endif /* CONFIG_MAGIC_SYSRQ */
632 tty_insert_flip_char(tty, buf[i], 0);
633 }
634
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 read_total += n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 }
637 throttled:
638 /* Wakeup write queue if necessary */
639 if (hp->do_wakeup) {
640 hp->do_wakeup = 0;
641 tty_wakeup(tty);
642 }
643 bail:
644 spin_unlock_irqrestore(&hp->lock, flags);
645
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500646 if (read_total)
647 tty_flip_buffer_push(tty);
648
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 return poll_mask;
650}
651
652#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
653extern cpumask_t cpus_in_xmon;
654#else
655static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
656#endif
657
658/*
659 * This kthread is either polling or interrupt driven. This is determined by
660 * calling hvc_poll() who determines whether a console adapter support
661 * interrupts.
662 */
663int khvcd(void *unused)
664{
665 int poll_mask;
666 struct hvc_struct *hp;
667
668 __set_current_state(TASK_RUNNING);
669 do {
670 poll_mask = 0;
671 hvc_kicked = 0;
672 wmb();
673 if (cpus_empty(cpus_in_xmon)) {
674 spin_lock(&hvc_structs_lock);
675 list_for_each_entry(hp, &hvc_structs, next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 poll_mask |= hvc_poll(hp);
677 }
678 spin_unlock(&hvc_structs_lock);
679 } else
680 poll_mask |= HVC_POLL_READ;
681 if (hvc_kicked)
682 continue;
683 if (poll_mask & HVC_POLL_QUICK) {
684 yield();
685 continue;
686 }
687 set_current_state(TASK_INTERRUPTIBLE);
688 if (!hvc_kicked) {
689 if (poll_mask == 0)
690 schedule();
691 else
692 msleep_interruptible(TIMEOUT);
693 }
694 __set_current_state(TASK_RUNNING);
695 } while (!kthread_should_stop());
696
697 return 0;
698}
699
700static struct tty_operations hvc_ops = {
701 .open = hvc_open,
702 .close = hvc_close,
703 .write = hvc_write,
704 .hangup = hvc_hangup,
705 .unthrottle = hvc_unthrottle,
706 .write_room = hvc_write_room,
707 .chars_in_buffer = hvc_chars_in_buffer,
708};
709
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710/* callback when the kboject ref count reaches zero. */
711static void destroy_hvc_struct(struct kobject *kobj)
712{
713 struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
714 unsigned long flags;
715
716 spin_lock(&hvc_structs_lock);
717
718 spin_lock_irqsave(&hp->lock, flags);
719 list_del(&(hp->next));
720 spin_unlock_irqrestore(&hp->lock, flags);
721
722 spin_unlock(&hvc_structs_lock);
723
724 kfree(hp);
725}
726
727static struct kobj_type hvc_kobj_type = {
728 .release = destroy_hvc_struct,
729};
730
Milton Miller030ffad2005-07-07 17:56:25 -0700731struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
732 struct hv_ops *ops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733{
734 struct hvc_struct *hp;
Milton Miller6f248082005-07-07 17:56:17 -0700735 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 hp = kmalloc(sizeof(*hp), GFP_KERNEL);
738 if (!hp)
Milton Milleracad9552005-07-07 17:56:24 -0700739 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740
741 memset(hp, 0x00, sizeof(*hp));
Milton Milleracad9552005-07-07 17:56:24 -0700742
743 hp->vtermno = vtermno;
744 hp->irq = irq;
Milton Miller030ffad2005-07-07 17:56:25 -0700745 hp->ops = ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746
747 kobject_init(&hp->kobj);
748 hp->kobj.ktype = &hvc_kobj_type;
749
750 spin_lock_init(&hp->lock);
751 spin_lock(&hvc_structs_lock);
Milton Miller6f248082005-07-07 17:56:17 -0700752
753 /*
754 * find index to use:
755 * see if this vterm id matches one registered for console.
756 */
757 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200758 if (vtermnos[i] == hp->vtermno &&
759 cons_ops[i] == hp->ops)
Milton Miller6f248082005-07-07 17:56:17 -0700760 break;
761
762 /* no matching slot, just use a counter */
763 if (i >= MAX_NR_HVC_CONSOLES)
764 i = ++last_hvc;
765
766 hp->index = i;
767
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 list_add_tail(&(hp->next), &hvc_structs);
769 spin_unlock(&hvc_structs_lock);
770
Milton Milleracad9552005-07-07 17:56:24 -0700771 return hp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772}
Milton Milleracad9552005-07-07 17:56:24 -0700773EXPORT_SYMBOL(hvc_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774
Milton Milleracad9552005-07-07 17:56:24 -0700775int __devexit hvc_remove(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 unsigned long flags;
778 struct kobject *kobjp;
779 struct tty_struct *tty;
780
781 spin_lock_irqsave(&hp->lock, flags);
782 tty = hp->tty;
783 kobjp = &hp->kobj;
784
785 if (hp->index < MAX_NR_HVC_CONSOLES)
786 vtermnos[hp->index] = -1;
787
788 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
789
790 spin_unlock_irqrestore(&hp->lock, flags);
791
792 /*
793 * We 'put' the instance that was grabbed when the kobject instance
794 * was intialized using kobject_init(). Let the last holder of this
795 * kobject cause it to be removed, which will probably be the tty_hangup
796 * below.
797 */
798 kobject_put(kobjp);
799
800 /*
801 * This function call will auto chain call hvc_hangup. The tty should
802 * always be valid at this time unless a simultaneous tty close already
803 * cleaned up the hvc_struct.
804 */
805 if (tty)
806 tty_hangup(tty);
807 return 0;
808}
Milton Milleracad9552005-07-07 17:56:24 -0700809EXPORT_SYMBOL(hvc_remove);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810
811/* Driver initialization. Follow console initialization. This is where the TTY
812 * interfaces start to become available. */
813int __init hvc_init(void)
814{
Michael Neuling55aab8c2006-03-25 17:30:00 +1100815 struct tty_driver *drv;
816
Milton Miller5f6d9c02005-07-07 17:56:21 -0700817 /* We need more than hvc_count adapters due to hotplug additions. */
Michael Neuling55aab8c2006-03-25 17:30:00 +1100818 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
819 if (!drv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 return -ENOMEM;
821
Michael Neuling55aab8c2006-03-25 17:30:00 +1100822 drv->owner = THIS_MODULE;
823 drv->devfs_name = "hvc/";
824 drv->driver_name = "hvc";
825 drv->name = "hvc";
826 drv->major = HVC_MAJOR;
827 drv->minor_start = HVC_MINOR;
828 drv->type = TTY_DRIVER_TYPE_SYSTEM;
829 drv->init_termios = tty_std_termios;
830 drv->flags = TTY_DRIVER_REAL_RAW;
831 tty_set_operations(drv, &hvc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 /* Always start the kthread because there can be hotplug vty adapters
834 * added later. */
835 hvc_task = kthread_run(khvcd, NULL, "khvcd");
836 if (IS_ERR(hvc_task)) {
837 panic("Couldn't create kthread for console.\n");
Michael Neuling55aab8c2006-03-25 17:30:00 +1100838 put_tty_driver(drv);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 return -EIO;
840 }
841
Michael Neuling55aab8c2006-03-25 17:30:00 +1100842 if (tty_register_driver(drv))
Anton Blanchardef4cbee2005-09-14 14:19:18 -0700843 panic("Couldn't register hvc console driver\n");
844
Michael Neuling55aab8c2006-03-25 17:30:00 +1100845 mb();
846 hvc_driver = drv;
Milton Milleracad9552005-07-07 17:56:24 -0700847 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848}
Milton Miller837dcfa2005-07-07 17:56:16 -0700849module_init(hvc_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
Milton Miller320da0d2005-07-07 17:56:20 -0700851/* This isn't particularily necessary due to this being a console driver
852 * but it is nice to be thorough.
853 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854static void __exit hvc_exit(void)
855{
856 kthread_stop(hvc_task);
857
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 tty_unregister_driver(hvc_driver);
859 /* return tty_struct instances allocated in hvc_init(). */
860 put_tty_driver(hvc_driver);
Milton Miller320da0d2005-07-07 17:56:20 -0700861 unregister_console(&hvc_con_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863module_exit(hvc_exit);