blob: 4053d1cd393f520101857047d52fc63b70efe7d7 [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
25#include <linux/console.h>
26#include <linux/cpumask.h>
27#include <linux/init.h>
28#include <linux/kbd_kern.h>
29#include <linux/kernel.h>
30#include <linux/kobject.h>
31#include <linux/kthread.h>
32#include <linux/list.h>
33#include <linux/module.h>
34#include <linux/major.h>
35#include <linux/sysrq.h>
36#include <linux/tty.h>
37#include <linux/tty_flip.h>
38#include <linux/sched.h>
39#include <linux/spinlock.h>
40#include <linux/delay.h>
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020041
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <asm/uaccess.h>
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020043
44#include "hvc_console.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
46#define HVC_MAJOR 229
47#define HVC_MINOR 0
48
49#define TIMEOUT (10)
50
51/*
52 * Wait this long per iteration while trying to push buffered data to the
53 * hypervisor before allowing the tty to complete a close operation.
54 */
55#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
56
57/*
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020058 * These sizes are most efficient for vio, because they are the
59 * native transfer size. We could make them selectable in the
60 * future to better deal with backends that want other buffer sizes.
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070062#define N_OUTBUF 16
63#define N_INBUF 16
64
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020065#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
Milton Miller837dcfa2005-07-07 17:56:16 -070067static struct tty_driver *hvc_driver;
68static struct task_struct *hvc_task;
69
70/* Picks up late kicks after list walk but before schedule() */
71static int hvc_kicked;
72
73#ifdef CONFIG_MAGIC_SYSRQ
74static int sysrq_pressed;
75#endif
76
Linus Torvalds1da177e2005-04-16 15:20:36 -070077struct hvc_struct {
78 spinlock_t lock;
79 int index;
80 struct tty_struct *tty;
81 unsigned int count;
82 int do_wakeup;
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +100083 char *outbuf;
84 int outbuf_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 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. */
Olof Johansson87fd7722006-09-07 15:18:08 -0500323 if (!(hp = hvc_get_by_index(tty->index)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
326 spin_lock_irqsave(&hp->lock, flags);
327 /* Check and then increment for fast path open. */
328 if (hp->count++ > 0) {
329 spin_unlock_irqrestore(&hp->lock, flags);
330 hvc_kick();
331 return 0;
332 } /* else count == 0 */
333
334 tty->driver_data = hp;
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500335 tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */
336
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 hp->tty = tty;
338 /* Save for request_irq outside of spin_lock. */
339 irq = hp->irq;
340 if (irq != NO_IRQ)
341 hp->irq_requested = 1;
342
343 kobjp = &hp->kobj;
344
345 spin_unlock_irqrestore(&hp->lock, flags);
346 /* check error, fallback to non-irq */
347 if (irq != NO_IRQ)
Thomas Gleixner0f2ed4c2006-07-01 19:29:33 -0700348 rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED, "hvc_console", hp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349
350 /*
351 * If the request_irq() fails and we return an error. The tty layer
352 * will call hvc_close() after a failed open but we don't want to clean
353 * up there so we'll clean up here and clear out the previously set
354 * tty fields and return the kobject reference.
355 */
356 if (rc) {
357 spin_lock_irqsave(&hp->lock, flags);
358 hp->tty = NULL;
359 hp->irq_requested = 0;
360 spin_unlock_irqrestore(&hp->lock, flags);
361 tty->driver_data = NULL;
362 kobject_put(kobjp);
363 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
364 }
365 /* Force wakeup of the polling thread */
366 hvc_kick();
367
368 return rc;
369}
370
371static void hvc_close(struct tty_struct *tty, struct file * filp)
372{
373 struct hvc_struct *hp;
374 struct kobject *kobjp;
375 int irq = NO_IRQ;
376 unsigned long flags;
377
378 if (tty_hung_up_p(filp))
379 return;
380
381 /*
382 * No driver_data means that this close was issued after a failed
383 * hvc_open by the tty layer's release_dev() function and we can just
384 * exit cleanly because the kobject reference wasn't made.
385 */
386 if (!tty->driver_data)
387 return;
388
389 hp = tty->driver_data;
390 spin_lock_irqsave(&hp->lock, flags);
391
392 kobjp = &hp->kobj;
393 if (--hp->count == 0) {
394 if (hp->irq_requested)
395 irq = hp->irq;
396 hp->irq_requested = 0;
397
398 /* We are done with the tty pointer now. */
399 hp->tty = NULL;
400 spin_unlock_irqrestore(&hp->lock, flags);
401
402 /*
403 * Chain calls chars_in_buffer() and returns immediately if
404 * there is no buffered data otherwise sleeps on a wait queue
405 * waking periodically to check chars_in_buffer().
406 */
407 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
408
409 if (irq != NO_IRQ)
410 free_irq(irq, hp);
411
412 } else {
413 if (hp->count < 0)
414 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
415 hp->vtermno, hp->count);
416 spin_unlock_irqrestore(&hp->lock, flags);
417 }
418
419 kobject_put(kobjp);
420}
421
422static void hvc_hangup(struct tty_struct *tty)
423{
424 struct hvc_struct *hp = tty->driver_data;
425 unsigned long flags;
426 int irq = NO_IRQ;
427 int temp_open_count;
428 struct kobject *kobjp;
429
430 if (!hp)
431 return;
432
433 spin_lock_irqsave(&hp->lock, flags);
434
435 /*
436 * The N_TTY line discipline has problems such that in a close vs
437 * open->hangup case this can be called after the final close so prevent
438 * that from happening for now.
439 */
440 if (hp->count <= 0) {
441 spin_unlock_irqrestore(&hp->lock, flags);
442 return;
443 }
444
445 kobjp = &hp->kobj;
446 temp_open_count = hp->count;
447 hp->count = 0;
448 hp->n_outbuf = 0;
449 hp->tty = NULL;
450 if (hp->irq_requested)
451 /* Saved for use outside of spin_lock. */
452 irq = hp->irq;
453 hp->irq_requested = 0;
454 spin_unlock_irqrestore(&hp->lock, flags);
455 if (irq != NO_IRQ)
456 free_irq(irq, hp);
457 while(temp_open_count) {
458 --temp_open_count;
459 kobject_put(kobjp);
460 }
461}
462
463/*
464 * Push buffered characters whether they were just recently buffered or waiting
465 * on a blocked hypervisor. Call this function with hp->lock held.
466 */
467static void hvc_push(struct hvc_struct *hp)
468{
469 int n;
470
Milton Miller030ffad2005-07-07 17:56:25 -0700471 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 if (n <= 0) {
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200473 if (n == 0) {
474 hp->do_wakeup = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 return;
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200476 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 /* throw away output on error; this happens when
478 there is no session connected to the vterm. */
479 hp->n_outbuf = 0;
480 } else
481 hp->n_outbuf -= n;
482 if (hp->n_outbuf > 0)
483 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
484 else
485 hp->do_wakeup = 1;
486}
487
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200488static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200490 struct hvc_struct *hp = tty->driver_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 unsigned long flags;
492 int rsize, written = 0;
493
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200494 /* This write was probably executed during a tty close. */
495 if (!hp)
496 return -EPIPE;
497
498 if (hp->count <= 0)
499 return -EIO;
500
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 spin_lock_irqsave(&hp->lock, flags);
502
503 /* Push pending writes */
504 if (hp->n_outbuf > 0)
505 hvc_push(hp);
506
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000507 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 if (rsize > count)
509 rsize = count;
510 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
511 count -= rsize;
512 buf += rsize;
513 hp->n_outbuf += rsize;
514 written += rsize;
515 hvc_push(hp);
516 }
517 spin_unlock_irqrestore(&hp->lock, flags);
518
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 /*
520 * Racy, but harmless, kick thread if there is still pending data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 */
522 if (hp->n_outbuf)
523 hvc_kick();
524
525 return written;
526}
527
528/*
529 * This is actually a contract between the driver and the tty layer outlining
530 * how much write room the driver can guarentee will be sent OR BUFFERED. This
531 * driver MUST honor the return value.
532 */
533static int hvc_write_room(struct tty_struct *tty)
534{
535 struct hvc_struct *hp = tty->driver_data;
536
537 if (!hp)
538 return -1;
539
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000540 return hp->outbuf_size - hp->n_outbuf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541}
542
543static int hvc_chars_in_buffer(struct tty_struct *tty)
544{
545 struct hvc_struct *hp = tty->driver_data;
546
547 if (!hp)
548 return -1;
549 return hp->n_outbuf;
550}
551
552#define HVC_POLL_READ 0x00000001
553#define HVC_POLL_WRITE 0x00000002
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554
555static int hvc_poll(struct hvc_struct *hp)
556{
557 struct tty_struct *tty;
558 int i, n, poll_mask = 0;
559 char buf[N_INBUF] __ALIGNED__;
560 unsigned long flags;
561 int read_total = 0;
562
563 spin_lock_irqsave(&hp->lock, flags);
564
565 /* Push pending writes */
566 if (hp->n_outbuf > 0)
567 hvc_push(hp);
Michael Ellermanb5374462006-06-07 17:10:03 +1000568
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 /* Reschedule us if still some write pending */
570 if (hp->n_outbuf > 0)
571 poll_mask |= HVC_POLL_WRITE;
572
573 /* No tty attached, just skip */
574 tty = hp->tty;
575 if (tty == NULL)
576 goto bail;
577
578 /* Now check if we can get data (are we throttled ?) */
579 if (test_bit(TTY_THROTTLED, &tty->flags))
580 goto throttled;
581
582 /* If we aren't interrupt driven and aren't throttled, we always
583 * request a reschedule
584 */
585 if (hp->irq == NO_IRQ)
586 poll_mask |= HVC_POLL_READ;
587
588 /* Read data if any */
589 for (;;) {
Alan Cox33f0f882006-01-09 20:54:13 -0800590 int count = tty_buffer_request_room(tty, N_INBUF);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591
592 /* If flip is full, just reschedule a later read */
593 if (count == 0) {
594 poll_mask |= HVC_POLL_READ;
595 break;
596 }
597
Milton Miller030ffad2005-07-07 17:56:25 -0700598 n = hp->ops->get_chars(hp->vtermno, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 if (n <= 0) {
600 /* Hangup the tty when disconnected from host */
601 if (n == -EPIPE) {
602 spin_unlock_irqrestore(&hp->lock, flags);
603 tty_hangup(tty);
604 spin_lock_irqsave(&hp->lock, flags);
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200605 } else if ( n == -EAGAIN ) {
606 /*
607 * Some back-ends can only ensure a certain min
608 * num of bytes read, which may be > 'count'.
609 * Let the tty clear the flip buff to make room.
610 */
611 poll_mask |= HVC_POLL_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 }
613 break;
614 }
615 for (i = 0; i < n; ++i) {
616#ifdef CONFIG_MAGIC_SYSRQ
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700617 if (hp->index == hvc_con_driver.index) {
618 /* Handle the SysRq Hack */
619 /* XXX should support a sequence */
620 if (buf[i] == '\x0f') { /* ^O */
621 sysrq_pressed = 1;
622 continue;
623 } else if (sysrq_pressed) {
624 handle_sysrq(buf[i], NULL, tty);
625 sysrq_pressed = 0;
626 continue;
627 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 }
629#endif /* CONFIG_MAGIC_SYSRQ */
630 tty_insert_flip_char(tty, buf[i], 0);
631 }
632
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 read_total += n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 }
635 throttled:
636 /* Wakeup write queue if necessary */
637 if (hp->do_wakeup) {
638 hp->do_wakeup = 0;
639 tty_wakeup(tty);
640 }
641 bail:
642 spin_unlock_irqrestore(&hp->lock, flags);
643
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500644 if (read_total)
645 tty_flip_buffer_push(tty);
646
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 return poll_mask;
648}
649
650#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
651extern cpumask_t cpus_in_xmon;
652#else
653static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
654#endif
655
656/*
657 * This kthread is either polling or interrupt driven. This is determined by
658 * calling hvc_poll() who determines whether a console adapter support
659 * interrupts.
660 */
661int khvcd(void *unused)
662{
663 int poll_mask;
664 struct hvc_struct *hp;
665
666 __set_current_state(TASK_RUNNING);
667 do {
668 poll_mask = 0;
669 hvc_kicked = 0;
Andrew Mortonb64074e2006-09-16 12:15:38 -0700670 try_to_freeze();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 wmb();
672 if (cpus_empty(cpus_in_xmon)) {
673 spin_lock(&hvc_structs_lock);
674 list_for_each_entry(hp, &hvc_structs, next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 poll_mask |= hvc_poll(hp);
676 }
677 spin_unlock(&hvc_structs_lock);
678 } else
679 poll_mask |= HVC_POLL_READ;
680 if (hvc_kicked)
681 continue;
Michael Ellermanb5374462006-06-07 17:10:03 +1000682 if (poll_mask & HVC_POLL_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 yield();
684 continue;
685 }
686 set_current_state(TASK_INTERRUPTIBLE);
687 if (!hvc_kicked) {
688 if (poll_mask == 0)
689 schedule();
690 else
691 msleep_interruptible(TIMEOUT);
692 }
693 __set_current_state(TASK_RUNNING);
694 } while (!kthread_should_stop());
695
696 return 0;
697}
698
Jeff Dikeb68e31d2006-10-02 02:17:18 -0700699static const struct tty_operations hvc_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 .open = hvc_open,
701 .close = hvc_close,
702 .write = hvc_write,
703 .hangup = hvc_hangup,
704 .unthrottle = hvc_unthrottle,
705 .write_room = hvc_write_room,
706 .chars_in_buffer = hvc_chars_in_buffer,
707};
708
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709/* callback when the kboject ref count reaches zero. */
710static void destroy_hvc_struct(struct kobject *kobj)
711{
712 struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
713 unsigned long flags;
714
715 spin_lock(&hvc_structs_lock);
716
717 spin_lock_irqsave(&hp->lock, flags);
718 list_del(&(hp->next));
719 spin_unlock_irqrestore(&hp->lock, flags);
720
721 spin_unlock(&hvc_structs_lock);
722
723 kfree(hp);
724}
725
726static struct kobj_type hvc_kobj_type = {
727 .release = destroy_hvc_struct,
728};
729
Milton Miller030ffad2005-07-07 17:56:25 -0700730struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000731 struct hv_ops *ops, int outbuf_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732{
733 struct hvc_struct *hp;
Milton Miller6f248082005-07-07 17:56:17 -0700734 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000736 hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
737 GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 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;
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000746 hp->outbuf_size = outbuf_size;
747 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
749 kobject_init(&hp->kobj);
750 hp->kobj.ktype = &hvc_kobj_type;
751
752 spin_lock_init(&hp->lock);
753 spin_lock(&hvc_structs_lock);
Milton Miller6f248082005-07-07 17:56:17 -0700754
755 /*
756 * find index to use:
757 * see if this vterm id matches one registered for console.
758 */
759 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200760 if (vtermnos[i] == hp->vtermno &&
761 cons_ops[i] == hp->ops)
Milton Miller6f248082005-07-07 17:56:17 -0700762 break;
763
764 /* no matching slot, just use a counter */
765 if (i >= MAX_NR_HVC_CONSOLES)
766 i = ++last_hvc;
767
768 hp->index = i;
769
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 list_add_tail(&(hp->next), &hvc_structs);
771 spin_unlock(&hvc_structs_lock);
772
Milton Milleracad9552005-07-07 17:56:24 -0700773 return hp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774}
Milton Milleracad9552005-07-07 17:56:24 -0700775EXPORT_SYMBOL(hvc_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776
Milton Milleracad9552005-07-07 17:56:24 -0700777int __devexit hvc_remove(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 unsigned long flags;
780 struct kobject *kobjp;
781 struct tty_struct *tty;
782
783 spin_lock_irqsave(&hp->lock, flags);
784 tty = hp->tty;
785 kobjp = &hp->kobj;
786
787 if (hp->index < MAX_NR_HVC_CONSOLES)
788 vtermnos[hp->index] = -1;
789
790 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
791
792 spin_unlock_irqrestore(&hp->lock, flags);
793
794 /*
795 * We 'put' the instance that was grabbed when the kobject instance
796 * was intialized using kobject_init(). Let the last holder of this
797 * kobject cause it to be removed, which will probably be the tty_hangup
798 * below.
799 */
800 kobject_put(kobjp);
801
802 /*
803 * This function call will auto chain call hvc_hangup. The tty should
804 * always be valid at this time unless a simultaneous tty close already
805 * cleaned up the hvc_struct.
806 */
807 if (tty)
808 tty_hangup(tty);
809 return 0;
810}
Milton Milleracad9552005-07-07 17:56:24 -0700811EXPORT_SYMBOL(hvc_remove);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812
813/* Driver initialization. Follow console initialization. This is where the TTY
814 * interfaces start to become available. */
815int __init hvc_init(void)
816{
Michael Neuling55aab8c2006-03-25 17:30:00 +1100817 struct tty_driver *drv;
818
Milton Miller5f6d9c02005-07-07 17:56:21 -0700819 /* We need more than hvc_count adapters due to hotplug additions. */
Michael Neuling55aab8c2006-03-25 17:30:00 +1100820 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
821 if (!drv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 return -ENOMEM;
823
Michael Neuling55aab8c2006-03-25 17:30:00 +1100824 drv->owner = THIS_MODULE;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100825 drv->driver_name = "hvc";
826 drv->name = "hvc";
827 drv->major = HVC_MAJOR;
828 drv->minor_start = HVC_MINOR;
829 drv->type = TTY_DRIVER_TYPE_SYSTEM;
830 drv->init_termios = tty_std_termios;
831 drv->flags = TTY_DRIVER_REAL_RAW;
832 tty_set_operations(drv, &hvc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 /* Always start the kthread because there can be hotplug vty adapters
835 * added later. */
836 hvc_task = kthread_run(khvcd, NULL, "khvcd");
837 if (IS_ERR(hvc_task)) {
838 panic("Couldn't create kthread for console.\n");
Michael Neuling55aab8c2006-03-25 17:30:00 +1100839 put_tty_driver(drv);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 return -EIO;
841 }
842
Michael Neuling55aab8c2006-03-25 17:30:00 +1100843 if (tty_register_driver(drv))
Anton Blanchardef4cbee2005-09-14 14:19:18 -0700844 panic("Couldn't register hvc console driver\n");
845
Michael Neuling55aab8c2006-03-25 17:30:00 +1100846 mb();
847 hvc_driver = drv;
Milton Milleracad9552005-07-07 17:56:24 -0700848 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849}
Milton Miller837dcfa2005-07-07 17:56:16 -0700850module_init(hvc_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851
Milton Miller320da0d2005-07-07 17:56:20 -0700852/* This isn't particularily necessary due to this being a console driver
853 * but it is nice to be thorough.
854 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855static void __exit hvc_exit(void)
856{
857 kthread_stop(hvc_task);
858
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 tty_unregister_driver(hvc_driver);
860 /* return tty_struct instances allocated in hvc_init(). */
861 put_tty_driver(hvc_driver);
Milton Miller320da0d2005-07-07 17:56:20 -0700862 unregister_console(&hvc_con_driver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864module_exit(hvc_exit);