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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);
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000164 if (r <= 0) {
Milton Miller837dcfa2005-07-07 17:56:16 -0700165 /* 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) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 /* We are done with the tty pointer now. */
371 hp->tty = NULL;
372 spin_unlock_irqrestore(&hp->lock, flags);
373
Christian Borntraegereef26222008-10-12 21:51:31 +0000374 if (hp->ops->notifier_del)
375 hp->ops->notifier_del(hp, hp->data);
376
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000377 /* cancel pending tty resize work */
378 cancel_work_sync(&hp->tty_resize);
379
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 /*
381 * Chain calls chars_in_buffer() and returns immediately if
382 * there is no buffered data otherwise sleeps on a wait queue
383 * waking periodically to check chars_in_buffer().
384 */
385 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 } else {
387 if (hp->count < 0)
388 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
389 hp->vtermno, hp->count);
390 spin_unlock_irqrestore(&hp->lock, flags);
391 }
392
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800393 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394}
395
396static void hvc_hangup(struct tty_struct *tty)
397{
398 struct hvc_struct *hp = tty->driver_data;
399 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 int temp_open_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401
402 if (!hp)
403 return;
404
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000405 /* cancel pending tty resize work */
406 cancel_work_sync(&hp->tty_resize);
407
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 spin_lock_irqsave(&hp->lock, flags);
409
410 /*
411 * The N_TTY line discipline has problems such that in a close vs
412 * open->hangup case this can be called after the final close so prevent
413 * that from happening for now.
414 */
415 if (hp->count <= 0) {
416 spin_unlock_irqrestore(&hp->lock, flags);
417 return;
418 }
419
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 temp_open_count = hp->count;
421 hp->count = 0;
422 hp->n_outbuf = 0;
423 hp->tty = NULL;
Christian Borntraeger611e0972008-06-20 15:24:08 +0200424
Christian Borntraegereef26222008-10-12 21:51:31 +0000425 spin_unlock_irqrestore(&hp->lock, flags);
426
Hendrik Bruecknerfc362e22008-10-13 23:12:48 +0000427 if (hp->ops->notifier_hangup)
428 hp->ops->notifier_hangup(hp, hp->data);
Christian Borntraeger611e0972008-06-20 15:24:08 +0200429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 while(temp_open_count) {
431 --temp_open_count;
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800432 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 }
434}
435
436/*
437 * Push buffered characters whether they were just recently buffered or waiting
438 * on a blocked hypervisor. Call this function with hp->lock held.
439 */
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000440static int hvc_push(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441{
442 int n;
443
Milton Miller030ffad2005-07-07 17:56:25 -0700444 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 if (n <= 0) {
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200446 if (n == 0) {
447 hp->do_wakeup = 1;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000448 return 0;
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200449 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 /* throw away output on error; this happens when
451 there is no session connected to the vterm. */
452 hp->n_outbuf = 0;
453 } else
454 hp->n_outbuf -= n;
455 if (hp->n_outbuf > 0)
456 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
457 else
458 hp->do_wakeup = 1;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000459
460 return n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461}
462
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200463static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200465 struct hvc_struct *hp = tty->driver_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 unsigned long flags;
467 int rsize, written = 0;
468
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200469 /* This write was probably executed during a tty close. */
470 if (!hp)
471 return -EPIPE;
472
473 if (hp->count <= 0)
474 return -EIO;
475
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 spin_lock_irqsave(&hp->lock, flags);
477
478 /* Push pending writes */
479 if (hp->n_outbuf > 0)
480 hvc_push(hp);
481
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000482 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 if (rsize > count)
484 rsize = count;
485 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
486 count -= rsize;
487 buf += rsize;
488 hp->n_outbuf += rsize;
489 written += rsize;
490 hvc_push(hp);
491 }
492 spin_unlock_irqrestore(&hp->lock, flags);
493
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 /*
495 * Racy, but harmless, kick thread if there is still pending data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 */
497 if (hp->n_outbuf)
498 hvc_kick();
499
500 return written;
501}
502
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000503/**
504 * hvc_set_winsz() - Resize the hvc tty terminal window.
505 * @work: work structure.
506 *
507 * The routine shall not be called within an atomic context because it
508 * might sleep.
509 *
510 * Locking: hp->lock
511 */
512static void hvc_set_winsz(struct work_struct *work)
513{
514 struct hvc_struct *hp;
515 unsigned long hvc_flags;
516 struct tty_struct *tty;
517 struct winsize ws;
518
519 hp = container_of(work, struct hvc_struct, tty_resize);
520 if (!hp)
521 return;
522
523 spin_lock_irqsave(&hp->lock, hvc_flags);
524 if (!hp->tty) {
525 spin_unlock_irqrestore(&hp->lock, hvc_flags);
526 return;
527 }
528 ws = hp->ws;
529 tty = tty_kref_get(hp->tty);
530 spin_unlock_irqrestore(&hp->lock, hvc_flags);
531
532 tty_do_resize(tty, tty, &ws);
533 tty_kref_put(tty);
534}
535
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536/*
537 * This is actually a contract between the driver and the tty layer outlining
will schmidtc3ea6922007-04-18 00:54:51 +1000538 * how much write room the driver can guarantee will be sent OR BUFFERED. This
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 * driver MUST honor the return value.
540 */
541static int hvc_write_room(struct tty_struct *tty)
542{
543 struct hvc_struct *hp = tty->driver_data;
544
545 if (!hp)
546 return -1;
547
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000548 return hp->outbuf_size - hp->n_outbuf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549}
550
551static int hvc_chars_in_buffer(struct tty_struct *tty)
552{
553 struct hvc_struct *hp = tty->driver_data;
554
555 if (!hp)
556 return -1;
557 return hp->n_outbuf;
558}
559
Will Schmidtb7910722007-04-18 00:44:46 +1000560/*
561 * timeout will vary between the MIN and MAX values defined here. By default
562 * and during console activity we will use a default MIN_TIMEOUT of 10. When
563 * the console is idle, we increase the timeout value on each pass through
564 * msleep until we reach the max. This may be noticeable as a brief (average
565 * one second) delay on the console before the console responds to input when
566 * there has been no input for some time.
567 */
568#define MIN_TIMEOUT (10)
569#define MAX_TIMEOUT (2000)
570static u32 timeout = MIN_TIMEOUT;
571
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572#define HVC_POLL_READ 0x00000001
573#define HVC_POLL_WRITE 0x00000002
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
Christian Borntraeger611e0972008-06-20 15:24:08 +0200575int hvc_poll(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576{
577 struct tty_struct *tty;
578 int i, n, poll_mask = 0;
579 char buf[N_INBUF] __ALIGNED__;
580 unsigned long flags;
581 int read_total = 0;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000582 int written_total = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583
584 spin_lock_irqsave(&hp->lock, flags);
585
586 /* Push pending writes */
587 if (hp->n_outbuf > 0)
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000588 written_total = hvc_push(hp);
Michael Ellermanb5374462006-06-07 17:10:03 +1000589
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 /* Reschedule us if still some write pending */
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000591 if (hp->n_outbuf > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 poll_mask |= HVC_POLL_WRITE;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000593 /* If hvc_push() was not able to write, sleep a few msecs */
594 timeout = (written_total) ? 0 : MIN_TIMEOUT;
595 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596
597 /* No tty attached, just skip */
598 tty = hp->tty;
599 if (tty == NULL)
600 goto bail;
601
602 /* Now check if we can get data (are we throttled ?) */
603 if (test_bit(TTY_THROTTLED, &tty->flags))
604 goto throttled;
605
Christian Borntraeger611e0972008-06-20 15:24:08 +0200606 /* If we aren't notifier driven and aren't throttled, we always
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 * request a reschedule
608 */
Christian Borntraeger611e0972008-06-20 15:24:08 +0200609 if (!hp->irq_requested)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 poll_mask |= HVC_POLL_READ;
611
612 /* Read data if any */
613 for (;;) {
Alan Cox33f0f882006-01-09 20:54:13 -0800614 int count = tty_buffer_request_room(tty, N_INBUF);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615
616 /* If flip is full, just reschedule a later read */
617 if (count == 0) {
618 poll_mask |= HVC_POLL_READ;
619 break;
620 }
621
Milton Miller030ffad2005-07-07 17:56:25 -0700622 n = hp->ops->get_chars(hp->vtermno, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 if (n <= 0) {
624 /* Hangup the tty when disconnected from host */
625 if (n == -EPIPE) {
626 spin_unlock_irqrestore(&hp->lock, flags);
627 tty_hangup(tty);
628 spin_lock_irqsave(&hp->lock, flags);
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200629 } else if ( n == -EAGAIN ) {
630 /*
631 * Some back-ends can only ensure a certain min
632 * num of bytes read, which may be > 'count'.
633 * Let the tty clear the flip buff to make room.
634 */
635 poll_mask |= HVC_POLL_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 }
637 break;
638 }
639 for (i = 0; i < n; ++i) {
640#ifdef CONFIG_MAGIC_SYSRQ
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700641 if (hp->index == hvc_con_driver.index) {
642 /* Handle the SysRq Hack */
643 /* XXX should support a sequence */
644 if (buf[i] == '\x0f') { /* ^O */
Hendrik Brueckner368c1e32008-12-16 00:09:38 +0000645 /* if ^O is pressed again, reset
646 * sysrq_pressed and flip ^O char */
647 sysrq_pressed = !sysrq_pressed;
648 if (sysrq_pressed)
649 continue;
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700650 } else if (sysrq_pressed) {
David Howells7d12e782006-10-05 14:55:46 +0100651 handle_sysrq(buf[i], tty);
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700652 sysrq_pressed = 0;
653 continue;
654 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 }
656#endif /* CONFIG_MAGIC_SYSRQ */
657 tty_insert_flip_char(tty, buf[i], 0);
658 }
659
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 read_total += n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 }
662 throttled:
663 /* Wakeup write queue if necessary */
664 if (hp->do_wakeup) {
665 hp->do_wakeup = 0;
666 tty_wakeup(tty);
667 }
668 bail:
669 spin_unlock_irqrestore(&hp->lock, flags);
670
Will Schmidtb7910722007-04-18 00:44:46 +1000671 if (read_total) {
672 /* Activity is occurring, so reset the polling backoff value to
673 a minimum for performance. */
674 timeout = MIN_TIMEOUT;
675
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500676 tty_flip_buffer_push(tty);
Will Schmidtb7910722007-04-18 00:44:46 +1000677 }
678
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 return poll_mask;
680}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500681EXPORT_SYMBOL_GPL(hvc_poll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000683/**
684 * hvc_resize() - Update terminal window size information.
685 * @hp: HVC console pointer
686 * @ws: Terminal window size structure
687 *
688 * Stores the specified window size information in the hvc structure of @hp.
689 * The function schedule the tty resize update.
690 *
691 * Locking: Locking free; the function MUST be called holding hp->lock
692 */
693void hvc_resize(struct hvc_struct *hp, struct winsize ws)
694{
Hendrik Brueckner7947cf02008-11-18 01:28:28 +0000695 hp->ws = ws;
696 schedule_work(&hp->tty_resize);
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000697}
698
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699/*
700 * This kthread is either polling or interrupt driven. This is determined by
701 * calling hvc_poll() who determines whether a console adapter support
702 * interrupts.
703 */
Adrian Bunk5605d4d2007-07-09 11:37:38 -0700704static int khvcd(void *unused)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705{
706 int poll_mask;
707 struct hvc_struct *hp;
708
Rafael J. Wysocki83144182007-07-17 04:03:35 -0700709 set_freezable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 __set_current_state(TASK_RUNNING);
711 do {
712 poll_mask = 0;
713 hvc_kicked = 0;
Andrew Mortonb64074e2006-09-16 12:15:38 -0700714 try_to_freeze();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 wmb();
Michael Ellerman1c8950f2008-05-08 14:27:17 +1000716 if (!cpus_are_in_xmon()) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 spin_lock(&hvc_structs_lock);
718 list_for_each_entry(hp, &hvc_structs, next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 poll_mask |= hvc_poll(hp);
720 }
721 spin_unlock(&hvc_structs_lock);
722 } else
723 poll_mask |= HVC_POLL_READ;
724 if (hvc_kicked)
725 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 set_current_state(TASK_INTERRUPTIBLE);
727 if (!hvc_kicked) {
728 if (poll_mask == 0)
729 schedule();
Will Schmidtb7910722007-04-18 00:44:46 +1000730 else {
731 if (timeout < MAX_TIMEOUT)
732 timeout += (timeout >> 6) + 1;
733
734 msleep_interruptible(timeout);
735 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 }
737 __set_current_state(TASK_RUNNING);
738 } while (!kthread_should_stop());
739
740 return 0;
741}
742
Jeff Dikeb68e31d2006-10-02 02:17:18 -0700743static const struct tty_operations hvc_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 .open = hvc_open,
745 .close = hvc_close,
746 .write = hvc_write,
747 .hangup = hvc_hangup,
748 .unthrottle = hvc_unthrottle,
749 .write_room = hvc_write_room,
750 .chars_in_buffer = hvc_chars_in_buffer,
751};
752
Christian Borntraeger611e0972008-06-20 15:24:08 +0200753struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int data,
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000754 struct hv_ops *ops, int outbuf_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755{
756 struct hvc_struct *hp;
Milton Miller6f248082005-07-07 17:56:17 -0700757 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700759 /* We wait until a driver actually comes along */
760 if (!hvc_driver) {
761 int err = hvc_init();
762 if (err)
763 return ERR_PTR(err);
764 }
765
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000766 hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
767 GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 if (!hp)
Milton Milleracad9552005-07-07 17:56:24 -0700769 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
771 memset(hp, 0x00, sizeof(*hp));
Milton Milleracad9552005-07-07 17:56:24 -0700772
773 hp->vtermno = vtermno;
Christian Borntraeger611e0972008-06-20 15:24:08 +0200774 hp->data = data;
Milton Miller030ffad2005-07-07 17:56:25 -0700775 hp->ops = ops;
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000776 hp->outbuf_size = outbuf_size;
777 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800779 kref_init(&hp->kref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000781 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 spin_lock_init(&hp->lock);
783 spin_lock(&hvc_structs_lock);
Milton Miller6f248082005-07-07 17:56:17 -0700784
785 /*
786 * find index to use:
787 * see if this vterm id matches one registered for console.
788 */
789 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200790 if (vtermnos[i] == hp->vtermno &&
791 cons_ops[i] == hp->ops)
Milton Miller6f248082005-07-07 17:56:17 -0700792 break;
793
794 /* no matching slot, just use a counter */
795 if (i >= MAX_NR_HVC_CONSOLES)
796 i = ++last_hvc;
797
798 hp->index = i;
799
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 list_add_tail(&(hp->next), &hvc_structs);
801 spin_unlock(&hvc_structs_lock);
802
Milton Milleracad9552005-07-07 17:56:24 -0700803 return hp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500805EXPORT_SYMBOL_GPL(hvc_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
Hendrik Brueckner934752d2008-10-13 23:12:52 +0000807int hvc_remove(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 struct tty_struct *tty;
811
812 spin_lock_irqsave(&hp->lock, flags);
813 tty = hp->tty;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814
815 if (hp->index < MAX_NR_HVC_CONSOLES)
816 vtermnos[hp->index] = -1;
817
818 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
819
820 spin_unlock_irqrestore(&hp->lock, flags);
821
822 /*
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800823 * We 'put' the instance that was grabbed when the kref instance
824 * was initialized using kref_init(). Let the last holder of this
825 * kref cause it to be removed, which will probably be the tty_hangup
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 * below.
827 */
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800828 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829
830 /*
831 * This function call will auto chain call hvc_hangup. The tty should
832 * always be valid at this time unless a simultaneous tty close already
833 * cleaned up the hvc_struct.
834 */
835 if (tty)
836 tty_hangup(tty);
837 return 0;
838}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700840/* Driver initialization: called as soon as someone uses hvc_alloc(). */
841static int hvc_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842{
Michael Neuling55aab8c2006-03-25 17:30:00 +1100843 struct tty_driver *drv;
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700844 int err;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100845
Milton Miller5f6d9c02005-07-07 17:56:21 -0700846 /* We need more than hvc_count adapters due to hotplug additions. */
Michael Neuling55aab8c2006-03-25 17:30:00 +1100847 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700848 if (!drv) {
849 err = -ENOMEM;
850 goto out;
851 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852
Michael Neuling55aab8c2006-03-25 17:30:00 +1100853 drv->owner = THIS_MODULE;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100854 drv->driver_name = "hvc";
855 drv->name = "hvc";
856 drv->major = HVC_MAJOR;
857 drv->minor_start = HVC_MINOR;
858 drv->type = TTY_DRIVER_TYPE_SYSTEM;
859 drv->init_termios = tty_std_termios;
Hendrik Brueckner56ce9e22008-10-13 23:12:49 +0000860 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100861 tty_set_operations(drv, &hvc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 /* Always start the kthread because there can be hotplug vty adapters
864 * added later. */
865 hvc_task = kthread_run(khvcd, NULL, "khvcd");
866 if (IS_ERR(hvc_task)) {
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700867 printk(KERN_ERR "Couldn't create kthread for console.\n");
868 err = PTR_ERR(hvc_task);
869 goto put_tty;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 }
871
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700872 err = tty_register_driver(drv);
873 if (err) {
874 printk(KERN_ERR "Couldn't register hvc console driver\n");
875 goto stop_thread;
876 }
Anton Blanchardef4cbee2005-09-14 14:19:18 -0700877
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700878 /* FIXME: This mb() seems completely random. Remove it. */
Michael Neuling55aab8c2006-03-25 17:30:00 +1100879 mb();
880 hvc_driver = drv;
Milton Milleracad9552005-07-07 17:56:24 -0700881 return 0;
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700882
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700883stop_thread:
884 kthread_stop(hvc_task);
885 hvc_task = NULL;
Julia Lawall2571cd6a2008-10-13 10:31:49 +0100886put_tty:
887 put_tty_driver(drv);
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700888out:
889 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890}
891
will schmidtc3ea6922007-04-18 00:54:51 +1000892/* This isn't particularly necessary due to this being a console driver
Milton Miller320da0d2005-07-07 17:56:20 -0700893 * but it is nice to be thorough.
894 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895static void __exit hvc_exit(void)
896{
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700897 if (hvc_driver) {
898 kthread_stop(hvc_task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700900 tty_unregister_driver(hvc_driver);
901 /* return tty_struct instances allocated in hvc_init(). */
902 put_tty_driver(hvc_driver);
903 unregister_console(&hvc_con_driver);
904 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906module_exit(hvc_exit);