blob: fd64137b1ab915fb9384fa674ad54be65c5f0074 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <linux/kthread.h>
31#include <linux/list.h>
32#include <linux/module.h>
33#include <linux/major.h>
34#include <linux/sysrq.h>
35#include <linux/tty.h>
36#include <linux/tty_flip.h>
37#include <linux/sched.h>
38#include <linux/spinlock.h>
39#include <linux/delay.h>
Nigel Cunningham7dfb7102006-12-06 20:34:23 -080040#include <linux/freezer.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
Linus Torvalds1da177e2005-04-16 15:20:36 -070049/*
50 * Wait this long per iteration while trying to push buffered data to the
51 * hypervisor before allowing the tty to complete a close operation.
52 */
53#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
54
55/*
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020056 * These sizes are most efficient for vio, because they are the
57 * native transfer size. We could make them selectable in the
58 * future to better deal with backends that want other buffer sizes.
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070060#define N_OUTBUF 16
61#define N_INBUF 16
62
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020063#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
Milton Miller837dcfa2005-07-07 17:56:16 -070065static struct tty_driver *hvc_driver;
66static struct task_struct *hvc_task;
67
68/* Picks up late kicks after list walk but before schedule() */
69static int hvc_kicked;
70
Rusty Russell3e6c6f62007-10-16 23:30:13 -070071static int hvc_init(void);
72
Milton Miller837dcfa2005-07-07 17:56:16 -070073#ifdef CONFIG_MAGIC_SYSRQ
74static int sysrq_pressed;
75#endif
76
Linus Torvalds1da177e2005-04-16 15:20:36 -070077/* dynamic list of hvc_struct instances */
Denis Chengbed97592008-02-06 01:37:35 -080078static LIST_HEAD(hvc_structs);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
80/*
81 * Protect the list of hvc_struct instances from inserts and removals during
82 * list traversal.
83 */
84static DEFINE_SPINLOCK(hvc_structs_lock);
85
86/*
Milton Miller6f248082005-07-07 17:56:17 -070087 * This value is used to assign a tty->index value to a hvc_struct based
88 * upon order of exposure via hvc_probe(), when we can not match it to
will schmidtc3ea6922007-04-18 00:54:51 +100089 * a console candidate registered with hvc_instantiate().
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 */
Milton Miller6f248082005-07-07 17:56:17 -070091static int last_hvc = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
Linus Torvalds1da177e2005-04-16 15:20:36 -070093/*
will schmidtc3ea6922007-04-18 00:54:51 +100094 * Do not call this function with either the hvc_structs_lock or the hvc_struct
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -080095 * lock held. If successful, this function increments the kref reference
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 * count against the target hvc_struct so it should be released when finished.
97 */
Adrian Bunk4fa156e2007-05-08 00:24:24 -070098static struct hvc_struct *hvc_get_by_index(int index)
Linus Torvalds1da177e2005-04-16 15:20:36 -070099{
100 struct hvc_struct *hp;
101 unsigned long flags;
102
103 spin_lock(&hvc_structs_lock);
104
105 list_for_each_entry(hp, &hvc_structs, next) {
106 spin_lock_irqsave(&hp->lock, flags);
107 if (hp->index == index) {
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800108 kref_get(&hp->kref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 spin_unlock_irqrestore(&hp->lock, flags);
110 spin_unlock(&hvc_structs_lock);
111 return hp;
112 }
113 spin_unlock_irqrestore(&hp->lock, flags);
114 }
115 hp = NULL;
116
117 spin_unlock(&hvc_structs_lock);
118 return hp;
119}
120
Milton Miller837dcfa2005-07-07 17:56:16 -0700121
122/*
123 * Initial console vtermnos for console API usage prior to full console
124 * initialization. Any vty adapter outside this range will not have usable
125 * console interfaces but can still be used as a tty device. This has to be
126 * static because kmalloc will not work during early console init.
127 */
Milton Miller030ffad2005-07-07 17:56:25 -0700128static struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
Milton Miller64e4da52005-07-07 17:56:22 -0700129static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
130 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
Milton Miller837dcfa2005-07-07 17:56:16 -0700131
132/*
133 * Console APIs, NOT TTY. These APIs are available immediately when
134 * hvc_console_setup() finds adapters.
135 */
136
Adrian Bunk4fa156e2007-05-08 00:24:24 -0700137static void hvc_console_print(struct console *co, const char *b,
138 unsigned count)
Milton Miller837dcfa2005-07-07 17:56:16 -0700139{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200140 char c[N_OUTBUF] __ALIGNED__;
Milton Miller837dcfa2005-07-07 17:56:16 -0700141 unsigned i = 0, n = 0;
Milton Miller030ffad2005-07-07 17:56:25 -0700142 int r, donecr = 0, index = co->index;
Milton Miller837dcfa2005-07-07 17:56:16 -0700143
144 /* Console access attempt outside of acceptable console range. */
Milton Miller030ffad2005-07-07 17:56:25 -0700145 if (index >= MAX_NR_HVC_CONSOLES)
Milton Miller837dcfa2005-07-07 17:56:16 -0700146 return;
147
will schmidtc3ea6922007-04-18 00:54:51 +1000148 /* This console adapter was removed so it is not usable. */
Milton Miller030ffad2005-07-07 17:56:25 -0700149 if (vtermnos[index] < 0)
Milton Miller837dcfa2005-07-07 17:56:16 -0700150 return;
151
152 while (count > 0 || i > 0) {
153 if (count > 0 && i < sizeof(c)) {
154 if (b[n] == '\n' && !donecr) {
155 c[i++] = '\r';
156 donecr = 1;
157 } else {
158 c[i++] = b[n++];
159 donecr = 0;
160 --count;
161 }
162 } else {
Milton Miller030ffad2005-07-07 17:56:25 -0700163 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
Milton Miller837dcfa2005-07-07 17:56:16 -0700164 if (r < 0) {
165 /* throw away chars on error */
166 i = 0;
167 } else if (r > 0) {
168 i -= r;
169 if (i > 0)
170 memmove(c, c+r, i);
171 }
172 }
173 }
174}
175
176static struct tty_driver *hvc_console_device(struct console *c, int *index)
177{
Milton Miller7805b1b2005-07-07 17:56:23 -0700178 if (vtermnos[c->index] == -1)
179 return NULL;
180
Milton Miller837dcfa2005-07-07 17:56:16 -0700181 *index = c->index;
182 return hvc_driver;
183}
184
185static int __init hvc_console_setup(struct console *co, char *options)
186{
Milton Miller7805b1b2005-07-07 17:56:23 -0700187 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
188 return -ENODEV;
189
190 if (vtermnos[co->index] == -1)
191 return -ENODEV;
192
Milton Miller837dcfa2005-07-07 17:56:16 -0700193 return 0;
194}
195
Adrian Bunk4fa156e2007-05-08 00:24:24 -0700196static struct console hvc_con_driver = {
Milton Miller837dcfa2005-07-07 17:56:16 -0700197 .name = "hvc",
198 .write = hvc_console_print,
199 .device = hvc_console_device,
200 .setup = hvc_console_setup,
201 .flags = CON_PRINTBUFFER,
202 .index = -1,
203};
204
Milton Millerd5ee2572005-07-07 17:56:24 -0700205/*
will schmidtc3ea6922007-04-18 00:54:51 +1000206 * Early console initialization. Precedes driver initialization.
Milton Millerd5ee2572005-07-07 17:56:24 -0700207 *
208 * (1) we are first, and the user specified another driver
209 * -- index will remain -1
210 * (2) we are first and the user specified no driver
211 * -- index will be set to 0, then we will fail setup.
212 * (3) we are first and the user specified our driver
213 * -- index will be set to user specified driver, and we will fail
214 * (4) we are after driver, and this initcall will register us
215 * -- if the user didn't specify a driver then the console will match
216 *
217 * Note that for cases 2 and 3, we will match later when the io driver
218 * calls hvc_instantiate() and call register again.
219 */
Milton Miller837dcfa2005-07-07 17:56:16 -0700220static int __init hvc_console_init(void)
221{
Milton Miller837dcfa2005-07-07 17:56:16 -0700222 register_console(&hvc_con_driver);
223 return 0;
224}
225console_initcall(hvc_console_init);
226
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800227/* callback when the kboject ref count reaches zero. */
228static void destroy_hvc_struct(struct kref *kref)
229{
230 struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref);
231 unsigned long flags;
232
233 spin_lock(&hvc_structs_lock);
234
235 spin_lock_irqsave(&hp->lock, flags);
236 list_del(&(hp->next));
237 spin_unlock_irqrestore(&hp->lock, flags);
238
239 spin_unlock(&hvc_structs_lock);
240
241 kfree(hp);
242}
243
Milton Miller837dcfa2005-07-07 17:56:16 -0700244/*
Milton Miller6f248082005-07-07 17:56:17 -0700245 * hvc_instantiate() is an early console discovery method which locates
246 * consoles * prior to the vio subsystem discovering them. Hotplugged
247 * vty adapters do NOT get an hvc_instantiate() callback since they
248 * appear after early console init.
Milton Miller837dcfa2005-07-07 17:56:16 -0700249 */
Milton Miller030ffad2005-07-07 17:56:25 -0700250int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops)
Milton Miller837dcfa2005-07-07 17:56:16 -0700251{
Milton Miller7805b1b2005-07-07 17:56:23 -0700252 struct hvc_struct *hp;
253
Milton Miller837dcfa2005-07-07 17:56:16 -0700254 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
255 return -1;
256
257 if (vtermnos[index] != -1)
258 return -1;
259
will schmidtc3ea6922007-04-18 00:54:51 +1000260 /* make sure no no tty has been registered in this index */
Milton Miller7805b1b2005-07-07 17:56:23 -0700261 hp = hvc_get_by_index(index);
262 if (hp) {
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800263 kref_put(&hp->kref, destroy_hvc_struct);
Milton Miller7805b1b2005-07-07 17:56:23 -0700264 return -1;
265 }
266
Milton Miller837dcfa2005-07-07 17:56:16 -0700267 vtermnos[index] = vtermno;
Milton Miller030ffad2005-07-07 17:56:25 -0700268 cons_ops[index] = ops;
Milton Miller6f248082005-07-07 17:56:17 -0700269
will schmidtc3ea6922007-04-18 00:54:51 +1000270 /* reserve all indices up to and including this index */
Milton Miller6f248082005-07-07 17:56:17 -0700271 if (last_hvc < index)
272 last_hvc = index;
273
Milton Millerd5ee2572005-07-07 17:56:24 -0700274 /* if this index is what the user requested, then register
275 * now (setup won't fail at this point). It's ok to just
276 * call register again if previously .setup failed.
277 */
278 if (index == hvc_con_driver.index)
279 register_console(&hvc_con_driver);
280
Milton Miller837dcfa2005-07-07 17:56:16 -0700281 return 0;
282}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500283EXPORT_SYMBOL_GPL(hvc_instantiate);
Milton Miller837dcfa2005-07-07 17:56:16 -0700284
285/* Wake the sleeping khvcd */
Christian Borntraeger611e0972008-06-20 15:24:08 +0200286void hvc_kick(void)
Milton Miller837dcfa2005-07-07 17:56:16 -0700287{
288 hvc_kicked = 1;
289 wake_up_process(hvc_task);
290}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500291EXPORT_SYMBOL_GPL(hvc_kick);
Milton Miller837dcfa2005-07-07 17:56:16 -0700292
Milton Miller837dcfa2005-07-07 17:56:16 -0700293static void hvc_unthrottle(struct tty_struct *tty)
294{
295 hvc_kick();
296}
297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298/*
299 * The TTY interface won't be used until after the vio layer has exposed the vty
300 * adapter to the kernel.
301 */
302static int hvc_open(struct tty_struct *tty, struct file * filp)
303{
304 struct hvc_struct *hp;
305 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 int rc = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800308 /* Auto increments kref reference if found. */
Olof Johansson87fd7722006-09-07 15:18:08 -0500309 if (!(hp = hvc_get_by_index(tty->index)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311
312 spin_lock_irqsave(&hp->lock, flags);
313 /* Check and then increment for fast path open. */
314 if (hp->count++ > 0) {
315 spin_unlock_irqrestore(&hp->lock, flags);
316 hvc_kick();
317 return 0;
318 } /* else count == 0 */
319
320 tty->driver_data = hp;
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500321 tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */
322
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 hp->tty = tty;
Christian Borntraeger611e0972008-06-20 15:24:08 +0200324
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 spin_unlock_irqrestore(&hp->lock, flags);
Christian Borntraeger611e0972008-06-20 15:24:08 +0200326
Christian Borntraegerb1b135c2008-08-07 09:18:34 +0200327 if (hp->ops->notifier_add)
328 rc = hp->ops->notifier_add(hp, hp->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
330 /*
Christian Borntraeger611e0972008-06-20 15:24:08 +0200331 * If the notifier fails we return an error. The tty layer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 * will call hvc_close() after a failed open but we don't want to clean
333 * up there so we'll clean up here and clear out the previously set
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800334 * tty fields and return the kref reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 */
336 if (rc) {
337 spin_lock_irqsave(&hp->lock, flags);
338 hp->tty = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 spin_unlock_irqrestore(&hp->lock, flags);
340 tty->driver_data = NULL;
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800341 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
343 }
344 /* Force wakeup of the polling thread */
345 hvc_kick();
346
347 return rc;
348}
349
350static void hvc_close(struct tty_struct *tty, struct file * filp)
351{
352 struct hvc_struct *hp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 unsigned long flags;
354
355 if (tty_hung_up_p(filp))
356 return;
357
358 /*
359 * No driver_data means that this close was issued after a failed
360 * hvc_open by the tty layer's release_dev() function and we can just
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800361 * exit cleanly because the kref reference wasn't made.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 */
363 if (!tty->driver_data)
364 return;
365
366 hp = tty->driver_data;
367 spin_lock_irqsave(&hp->lock, flags);
368
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (--hp->count == 0) {
Christian Borntraeger611e0972008-06-20 15:24:08 +0200370 if (hp->ops->notifier_del)
371 hp->ops->notifier_del(hp, hp->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372
373 /* We are done with the tty pointer now. */
374 hp->tty = NULL;
375 spin_unlock_irqrestore(&hp->lock, flags);
376
377 /*
378 * Chain calls chars_in_buffer() and returns immediately if
379 * there is no buffered data otherwise sleeps on a wait queue
380 * waking periodically to check chars_in_buffer().
381 */
382 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 } else {
384 if (hp->count < 0)
385 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
386 hp->vtermno, hp->count);
387 spin_unlock_irqrestore(&hp->lock, flags);
388 }
389
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800390 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391}
392
393static void hvc_hangup(struct tty_struct *tty)
394{
395 struct hvc_struct *hp = tty->driver_data;
396 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 int temp_open_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398
399 if (!hp)
400 return;
401
402 spin_lock_irqsave(&hp->lock, flags);
403
404 /*
405 * The N_TTY line discipline has problems such that in a close vs
406 * open->hangup case this can be called after the final close so prevent
407 * that from happening for now.
408 */
409 if (hp->count <= 0) {
410 spin_unlock_irqrestore(&hp->lock, flags);
411 return;
412 }
413
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 temp_open_count = hp->count;
415 hp->count = 0;
416 hp->n_outbuf = 0;
417 hp->tty = NULL;
Christian Borntraeger611e0972008-06-20 15:24:08 +0200418
419 if (hp->ops->notifier_del)
420 hp->ops->notifier_del(hp, hp->data);
421
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 spin_unlock_irqrestore(&hp->lock, flags);
Christian Borntraeger611e0972008-06-20 15:24:08 +0200423
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 while(temp_open_count) {
425 --temp_open_count;
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800426 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 }
428}
429
430/*
431 * Push buffered characters whether they were just recently buffered or waiting
432 * on a blocked hypervisor. Call this function with hp->lock held.
433 */
434static void hvc_push(struct hvc_struct *hp)
435{
436 int n;
437
Milton Miller030ffad2005-07-07 17:56:25 -0700438 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 if (n <= 0) {
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200440 if (n == 0) {
441 hp->do_wakeup = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 return;
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200443 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 /* throw away output on error; this happens when
445 there is no session connected to the vterm. */
446 hp->n_outbuf = 0;
447 } else
448 hp->n_outbuf -= n;
449 if (hp->n_outbuf > 0)
450 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
451 else
452 hp->do_wakeup = 1;
453}
454
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200455static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200457 struct hvc_struct *hp = tty->driver_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 unsigned long flags;
459 int rsize, written = 0;
460
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200461 /* This write was probably executed during a tty close. */
462 if (!hp)
463 return -EPIPE;
464
465 if (hp->count <= 0)
466 return -EIO;
467
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 spin_lock_irqsave(&hp->lock, flags);
469
470 /* Push pending writes */
471 if (hp->n_outbuf > 0)
472 hvc_push(hp);
473
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000474 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 if (rsize > count)
476 rsize = count;
477 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
478 count -= rsize;
479 buf += rsize;
480 hp->n_outbuf += rsize;
481 written += rsize;
482 hvc_push(hp);
483 }
484 spin_unlock_irqrestore(&hp->lock, flags);
485
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 /*
487 * Racy, but harmless, kick thread if there is still pending data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 */
489 if (hp->n_outbuf)
490 hvc_kick();
491
492 return written;
493}
494
495/*
496 * This is actually a contract between the driver and the tty layer outlining
will schmidtc3ea6922007-04-18 00:54:51 +1000497 * how much write room the driver can guarantee will be sent OR BUFFERED. This
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 * driver MUST honor the return value.
499 */
500static int hvc_write_room(struct tty_struct *tty)
501{
502 struct hvc_struct *hp = tty->driver_data;
503
504 if (!hp)
505 return -1;
506
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000507 return hp->outbuf_size - hp->n_outbuf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508}
509
510static int hvc_chars_in_buffer(struct tty_struct *tty)
511{
512 struct hvc_struct *hp = tty->driver_data;
513
514 if (!hp)
515 return -1;
516 return hp->n_outbuf;
517}
518
Will Schmidtb7910722007-04-18 00:44:46 +1000519/*
520 * timeout will vary between the MIN and MAX values defined here. By default
521 * and during console activity we will use a default MIN_TIMEOUT of 10. When
522 * the console is idle, we increase the timeout value on each pass through
523 * msleep until we reach the max. This may be noticeable as a brief (average
524 * one second) delay on the console before the console responds to input when
525 * there has been no input for some time.
526 */
527#define MIN_TIMEOUT (10)
528#define MAX_TIMEOUT (2000)
529static u32 timeout = MIN_TIMEOUT;
530
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531#define HVC_POLL_READ 0x00000001
532#define HVC_POLL_WRITE 0x00000002
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533
Christian Borntraeger611e0972008-06-20 15:24:08 +0200534int hvc_poll(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535{
536 struct tty_struct *tty;
537 int i, n, poll_mask = 0;
538 char buf[N_INBUF] __ALIGNED__;
539 unsigned long flags;
540 int read_total = 0;
541
542 spin_lock_irqsave(&hp->lock, flags);
543
544 /* Push pending writes */
545 if (hp->n_outbuf > 0)
546 hvc_push(hp);
Michael Ellermanb5374462006-06-07 17:10:03 +1000547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 /* Reschedule us if still some write pending */
549 if (hp->n_outbuf > 0)
550 poll_mask |= HVC_POLL_WRITE;
551
552 /* No tty attached, just skip */
553 tty = hp->tty;
554 if (tty == NULL)
555 goto bail;
556
557 /* Now check if we can get data (are we throttled ?) */
558 if (test_bit(TTY_THROTTLED, &tty->flags))
559 goto throttled;
560
Christian Borntraeger611e0972008-06-20 15:24:08 +0200561 /* If we aren't notifier driven and aren't throttled, we always
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 * request a reschedule
563 */
Christian Borntraeger611e0972008-06-20 15:24:08 +0200564 if (!hp->irq_requested)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 poll_mask |= HVC_POLL_READ;
566
567 /* Read data if any */
568 for (;;) {
Alan Cox33f0f882006-01-09 20:54:13 -0800569 int count = tty_buffer_request_room(tty, N_INBUF);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570
571 /* If flip is full, just reschedule a later read */
572 if (count == 0) {
573 poll_mask |= HVC_POLL_READ;
574 break;
575 }
576
Milton Miller030ffad2005-07-07 17:56:25 -0700577 n = hp->ops->get_chars(hp->vtermno, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 if (n <= 0) {
579 /* Hangup the tty when disconnected from host */
580 if (n == -EPIPE) {
581 spin_unlock_irqrestore(&hp->lock, flags);
582 tty_hangup(tty);
583 spin_lock_irqsave(&hp->lock, flags);
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200584 } else if ( n == -EAGAIN ) {
585 /*
586 * Some back-ends can only ensure a certain min
587 * num of bytes read, which may be > 'count'.
588 * Let the tty clear the flip buff to make room.
589 */
590 poll_mask |= HVC_POLL_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 }
592 break;
593 }
594 for (i = 0; i < n; ++i) {
595#ifdef CONFIG_MAGIC_SYSRQ
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700596 if (hp->index == hvc_con_driver.index) {
597 /* Handle the SysRq Hack */
598 /* XXX should support a sequence */
599 if (buf[i] == '\x0f') { /* ^O */
600 sysrq_pressed = 1;
601 continue;
602 } else if (sysrq_pressed) {
David Howells7d12e782006-10-05 14:55:46 +0100603 handle_sysrq(buf[i], tty);
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700604 sysrq_pressed = 0;
605 continue;
606 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 }
608#endif /* CONFIG_MAGIC_SYSRQ */
609 tty_insert_flip_char(tty, buf[i], 0);
610 }
611
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 read_total += n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 }
614 throttled:
615 /* Wakeup write queue if necessary */
616 if (hp->do_wakeup) {
617 hp->do_wakeup = 0;
618 tty_wakeup(tty);
619 }
620 bail:
621 spin_unlock_irqrestore(&hp->lock, flags);
622
Will Schmidtb7910722007-04-18 00:44:46 +1000623 if (read_total) {
624 /* Activity is occurring, so reset the polling backoff value to
625 a minimum for performance. */
626 timeout = MIN_TIMEOUT;
627
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500628 tty_flip_buffer_push(tty);
Will Schmidtb7910722007-04-18 00:44:46 +1000629 }
630
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 return poll_mask;
632}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500633EXPORT_SYMBOL_GPL(hvc_poll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635/*
636 * This kthread is either polling or interrupt driven. This is determined by
637 * calling hvc_poll() who determines whether a console adapter support
638 * interrupts.
639 */
Adrian Bunk5605d4d2007-07-09 11:37:38 -0700640static int khvcd(void *unused)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641{
642 int poll_mask;
643 struct hvc_struct *hp;
644
Rafael J. Wysocki83144182007-07-17 04:03:35 -0700645 set_freezable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 __set_current_state(TASK_RUNNING);
647 do {
648 poll_mask = 0;
649 hvc_kicked = 0;
Andrew Mortonb64074e2006-09-16 12:15:38 -0700650 try_to_freeze();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 wmb();
Michael Ellerman1c8950f2008-05-08 14:27:17 +1000652 if (!cpus_are_in_xmon()) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 spin_lock(&hvc_structs_lock);
654 list_for_each_entry(hp, &hvc_structs, next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 poll_mask |= hvc_poll(hp);
656 }
657 spin_unlock(&hvc_structs_lock);
658 } else
659 poll_mask |= HVC_POLL_READ;
660 if (hvc_kicked)
661 continue;
Michael Ellermanb5374462006-06-07 17:10:03 +1000662 if (poll_mask & HVC_POLL_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 yield();
664 continue;
665 }
666 set_current_state(TASK_INTERRUPTIBLE);
667 if (!hvc_kicked) {
668 if (poll_mask == 0)
669 schedule();
Will Schmidtb7910722007-04-18 00:44:46 +1000670 else {
671 if (timeout < MAX_TIMEOUT)
672 timeout += (timeout >> 6) + 1;
673
674 msleep_interruptible(timeout);
675 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 }
677 __set_current_state(TASK_RUNNING);
678 } while (!kthread_should_stop());
679
680 return 0;
681}
682
Jeff Dikeb68e31d2006-10-02 02:17:18 -0700683static const struct tty_operations hvc_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 .open = hvc_open,
685 .close = hvc_close,
686 .write = hvc_write,
687 .hangup = hvc_hangup,
688 .unthrottle = hvc_unthrottle,
689 .write_room = hvc_write_room,
690 .chars_in_buffer = hvc_chars_in_buffer,
691};
692
Christian Borntraeger611e0972008-06-20 15:24:08 +0200693struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int data,
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000694 struct hv_ops *ops, int outbuf_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695{
696 struct hvc_struct *hp;
Milton Miller6f248082005-07-07 17:56:17 -0700697 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700699 /* We wait until a driver actually comes along */
700 if (!hvc_driver) {
701 int err = hvc_init();
702 if (err)
703 return ERR_PTR(err);
704 }
705
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000706 hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
707 GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 if (!hp)
Milton Milleracad9552005-07-07 17:56:24 -0700709 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710
711 memset(hp, 0x00, sizeof(*hp));
Milton Milleracad9552005-07-07 17:56:24 -0700712
713 hp->vtermno = vtermno;
Christian Borntraeger611e0972008-06-20 15:24:08 +0200714 hp->data = data;
Milton Miller030ffad2005-07-07 17:56:25 -0700715 hp->ops = ops;
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000716 hp->outbuf_size = outbuf_size;
717 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800719 kref_init(&hp->kref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720
721 spin_lock_init(&hp->lock);
722 spin_lock(&hvc_structs_lock);
Milton Miller6f248082005-07-07 17:56:17 -0700723
724 /*
725 * find index to use:
726 * see if this vterm id matches one registered for console.
727 */
728 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200729 if (vtermnos[i] == hp->vtermno &&
730 cons_ops[i] == hp->ops)
Milton Miller6f248082005-07-07 17:56:17 -0700731 break;
732
733 /* no matching slot, just use a counter */
734 if (i >= MAX_NR_HVC_CONSOLES)
735 i = ++last_hvc;
736
737 hp->index = i;
738
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 list_add_tail(&(hp->next), &hvc_structs);
740 spin_unlock(&hvc_structs_lock);
741
Milton Milleracad9552005-07-07 17:56:24 -0700742 return hp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500744EXPORT_SYMBOL_GPL(hvc_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745
Milton Milleracad9552005-07-07 17:56:24 -0700746int __devexit hvc_remove(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 struct tty_struct *tty;
750
751 spin_lock_irqsave(&hp->lock, flags);
752 tty = hp->tty;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753
754 if (hp->index < MAX_NR_HVC_CONSOLES)
755 vtermnos[hp->index] = -1;
756
757 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
758
759 spin_unlock_irqrestore(&hp->lock, flags);
760
761 /*
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800762 * We 'put' the instance that was grabbed when the kref instance
763 * was initialized using kref_init(). Let the last holder of this
764 * kref cause it to be removed, which will probably be the tty_hangup
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 * below.
766 */
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800767 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
769 /*
770 * This function call will auto chain call hvc_hangup. The tty should
771 * always be valid at this time unless a simultaneous tty close already
772 * cleaned up the hvc_struct.
773 */
774 if (tty)
775 tty_hangup(tty);
776 return 0;
777}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700779/* Driver initialization: called as soon as someone uses hvc_alloc(). */
780static int hvc_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781{
Michael Neuling55aab8c2006-03-25 17:30:00 +1100782 struct tty_driver *drv;
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700783 int err;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100784
Milton Miller5f6d9c02005-07-07 17:56:21 -0700785 /* We need more than hvc_count adapters due to hotplug additions. */
Michael Neuling55aab8c2006-03-25 17:30:00 +1100786 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700787 if (!drv) {
788 err = -ENOMEM;
789 goto out;
790 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791
Michael Neuling55aab8c2006-03-25 17:30:00 +1100792 drv->owner = THIS_MODULE;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100793 drv->driver_name = "hvc";
794 drv->name = "hvc";
795 drv->major = HVC_MAJOR;
796 drv->minor_start = HVC_MINOR;
797 drv->type = TTY_DRIVER_TYPE_SYSTEM;
798 drv->init_termios = tty_std_termios;
799 drv->flags = TTY_DRIVER_REAL_RAW;
800 tty_set_operations(drv, &hvc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 /* Always start the kthread because there can be hotplug vty adapters
803 * added later. */
804 hvc_task = kthread_run(khvcd, NULL, "khvcd");
805 if (IS_ERR(hvc_task)) {
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700806 printk(KERN_ERR "Couldn't create kthread for console.\n");
807 err = PTR_ERR(hvc_task);
808 goto put_tty;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 }
810
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700811 err = tty_register_driver(drv);
812 if (err) {
813 printk(KERN_ERR "Couldn't register hvc console driver\n");
814 goto stop_thread;
815 }
Anton Blanchardef4cbee2005-09-14 14:19:18 -0700816
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700817 /* FIXME: This mb() seems completely random. Remove it. */
Michael Neuling55aab8c2006-03-25 17:30:00 +1100818 mb();
819 hvc_driver = drv;
Milton Milleracad9552005-07-07 17:56:24 -0700820 return 0;
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700821
822put_tty:
823 put_tty_driver(hvc_driver);
824stop_thread:
825 kthread_stop(hvc_task);
826 hvc_task = NULL;
827out:
828 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829}
830
will schmidtc3ea6922007-04-18 00:54:51 +1000831/* This isn't particularly necessary due to this being a console driver
Milton Miller320da0d2005-07-07 17:56:20 -0700832 * but it is nice to be thorough.
833 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834static void __exit hvc_exit(void)
835{
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700836 if (hvc_driver) {
837 kthread_stop(hvc_task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700839 tty_unregister_driver(hvc_driver);
840 /* return tty_struct instances allocated in hvc_init(). */
841 put_tty_driver(hvc_driver);
842 unregister_console(&hvc_con_driver);
843 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845module_exit(hvc_exit);