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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090041#include <linux/slab.h>
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020042
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <asm/uaccess.h>
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020044
45#include "hvc_console.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
47#define HVC_MAJOR 229
48#define HVC_MINOR 0
49
Linus Torvalds1da177e2005-04-16 15:20:36 -070050/*
51 * Wait this long per iteration while trying to push buffered data to the
52 * hypervisor before allowing the tty to complete a close operation.
53 */
54#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
55
56/*
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020057 * These sizes are most efficient for vio, because they are the
58 * native transfer size. We could make them selectable in the
59 * future to better deal with backends that want other buffer sizes.
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070061#define N_OUTBUF 16
62#define N_INBUF 16
63
Ryan S. Arnold45d607e2006-03-27 21:25:16 +020064#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Milton Miller837dcfa2005-07-07 17:56:16 -070066static struct tty_driver *hvc_driver;
67static struct task_struct *hvc_task;
68
69/* Picks up late kicks after list walk but before schedule() */
70static int hvc_kicked;
71
Rusty Russell3e6c6f62007-10-16 23:30:13 -070072static int hvc_init(void);
73
Milton Miller837dcfa2005-07-07 17:56:16 -070074#ifdef CONFIG_MAGIC_SYSRQ
75static int sysrq_pressed;
76#endif
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078/* dynamic list of hvc_struct instances */
Denis Chengbed97592008-02-06 01:37:35 -080079static LIST_HEAD(hvc_structs);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
81/*
82 * Protect the list of hvc_struct instances from inserts and removals during
83 * list traversal.
84 */
85static DEFINE_SPINLOCK(hvc_structs_lock);
86
87/*
Milton Miller6f248082005-07-07 17:56:17 -070088 * This value is used to assign a tty->index value to a hvc_struct based
89 * upon order of exposure via hvc_probe(), when we can not match it to
will schmidtc3ea6922007-04-18 00:54:51 +100090 * a console candidate registered with hvc_instantiate().
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 */
Milton Miller6f248082005-07-07 17:56:17 -070092static int last_hvc = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Linus Torvalds1da177e2005-04-16 15:20:36 -070094/*
will schmidtc3ea6922007-04-18 00:54:51 +100095 * Do not call this function with either the hvc_structs_lock or the hvc_struct
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -080096 * lock held. If successful, this function increments the kref reference
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 * count against the target hvc_struct so it should be released when finished.
98 */
Adrian Bunk4fa156e2007-05-08 00:24:24 -070099static struct hvc_struct *hvc_get_by_index(int index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100{
101 struct hvc_struct *hp;
102 unsigned long flags;
103
104 spin_lock(&hvc_structs_lock);
105
106 list_for_each_entry(hp, &hvc_structs, next) {
107 spin_lock_irqsave(&hp->lock, flags);
108 if (hp->index == index) {
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800109 kref_get(&hp->kref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 spin_unlock_irqrestore(&hp->lock, flags);
111 spin_unlock(&hvc_structs_lock);
112 return hp;
113 }
114 spin_unlock_irqrestore(&hp->lock, flags);
115 }
116 hp = NULL;
117
118 spin_unlock(&hvc_structs_lock);
119 return hp;
120}
121
Milton Miller837dcfa2005-07-07 17:56:16 -0700122
123/*
124 * Initial console vtermnos for console API usage prior to full console
125 * initialization. Any vty adapter outside this range will not have usable
126 * console interfaces but can still be used as a tty device. This has to be
127 * static because kmalloc will not work during early console init.
128 */
Rusty Russellb5113062010-01-18 03:44:57 +0000129static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
Milton Miller64e4da52005-07-07 17:56:22 -0700130static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
131 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
Milton Miller837dcfa2005-07-07 17:56:16 -0700132
133/*
134 * Console APIs, NOT TTY. These APIs are available immediately when
135 * hvc_console_setup() finds adapters.
136 */
137
Adrian Bunk4fa156e2007-05-08 00:24:24 -0700138static void hvc_console_print(struct console *co, const char *b,
139 unsigned count)
Milton Miller837dcfa2005-07-07 17:56:16 -0700140{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200141 char c[N_OUTBUF] __ALIGNED__;
Milton Miller837dcfa2005-07-07 17:56:16 -0700142 unsigned i = 0, n = 0;
Milton Miller030ffad2005-07-07 17:56:25 -0700143 int r, donecr = 0, index = co->index;
Milton Miller837dcfa2005-07-07 17:56:16 -0700144
145 /* Console access attempt outside of acceptable console range. */
Milton Miller030ffad2005-07-07 17:56:25 -0700146 if (index >= MAX_NR_HVC_CONSOLES)
Milton Miller837dcfa2005-07-07 17:56:16 -0700147 return;
148
will schmidtc3ea6922007-04-18 00:54:51 +1000149 /* This console adapter was removed so it is not usable. */
Roel Kluinecfcbee2009-12-09 12:34:16 -0800150 if (vtermnos[index] == -1)
Milton Miller837dcfa2005-07-07 17:56:16 -0700151 return;
152
153 while (count > 0 || i > 0) {
154 if (count > 0 && i < sizeof(c)) {
155 if (b[n] == '\n' && !donecr) {
156 c[i++] = '\r';
157 donecr = 1;
158 } else {
159 c[i++] = b[n++];
160 donecr = 0;
161 --count;
162 }
163 } else {
Milton Miller030ffad2005-07-07 17:56:25 -0700164 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000165 if (r <= 0) {
Milton Miller837dcfa2005-07-07 17:56:16 -0700166 /* throw away chars on error */
167 i = 0;
168 } else if (r > 0) {
169 i -= r;
170 if (i > 0)
171 memmove(c, c+r, i);
172 }
173 }
174 }
175}
176
177static struct tty_driver *hvc_console_device(struct console *c, int *index)
178{
Milton Miller7805b1b2005-07-07 17:56:23 -0700179 if (vtermnos[c->index] == -1)
180 return NULL;
181
Milton Miller837dcfa2005-07-07 17:56:16 -0700182 *index = c->index;
183 return hvc_driver;
184}
185
186static int __init hvc_console_setup(struct console *co, char *options)
187{
Milton Miller7805b1b2005-07-07 17:56:23 -0700188 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
189 return -ENODEV;
190
191 if (vtermnos[co->index] == -1)
192 return -ENODEV;
193
Milton Miller837dcfa2005-07-07 17:56:16 -0700194 return 0;
195}
196
Adrian Bunk4fa156e2007-05-08 00:24:24 -0700197static struct console hvc_con_driver = {
Milton Miller837dcfa2005-07-07 17:56:16 -0700198 .name = "hvc",
199 .write = hvc_console_print,
200 .device = hvc_console_device,
201 .setup = hvc_console_setup,
202 .flags = CON_PRINTBUFFER,
203 .index = -1,
204};
205
Milton Millerd5ee2572005-07-07 17:56:24 -0700206/*
will schmidtc3ea6922007-04-18 00:54:51 +1000207 * Early console initialization. Precedes driver initialization.
Milton Millerd5ee2572005-07-07 17:56:24 -0700208 *
209 * (1) we are first, and the user specified another driver
210 * -- index will remain -1
211 * (2) we are first and the user specified no driver
212 * -- index will be set to 0, then we will fail setup.
213 * (3) we are first and the user specified our driver
214 * -- index will be set to user specified driver, and we will fail
215 * (4) we are after driver, and this initcall will register us
216 * -- if the user didn't specify a driver then the console will match
217 *
218 * Note that for cases 2 and 3, we will match later when the io driver
219 * calls hvc_instantiate() and call register again.
220 */
Milton Miller837dcfa2005-07-07 17:56:16 -0700221static int __init hvc_console_init(void)
222{
Milton Miller837dcfa2005-07-07 17:56:16 -0700223 register_console(&hvc_con_driver);
224 return 0;
225}
226console_initcall(hvc_console_init);
227
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800228/* callback when the kboject ref count reaches zero. */
229static void destroy_hvc_struct(struct kref *kref)
230{
231 struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref);
232 unsigned long flags;
233
234 spin_lock(&hvc_structs_lock);
235
236 spin_lock_irqsave(&hp->lock, flags);
237 list_del(&(hp->next));
238 spin_unlock_irqrestore(&hp->lock, flags);
239
240 spin_unlock(&hvc_structs_lock);
241
242 kfree(hp);
243}
244
Milton Miller837dcfa2005-07-07 17:56:16 -0700245/*
Milton Miller6f248082005-07-07 17:56:17 -0700246 * hvc_instantiate() is an early console discovery method which locates
247 * consoles * prior to the vio subsystem discovering them. Hotplugged
248 * vty adapters do NOT get an hvc_instantiate() callback since they
249 * appear after early console init.
Milton Miller837dcfa2005-07-07 17:56:16 -0700250 */
Rusty Russellb5113062010-01-18 03:44:57 +0000251int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
Milton Miller837dcfa2005-07-07 17:56:16 -0700252{
Milton Miller7805b1b2005-07-07 17:56:23 -0700253 struct hvc_struct *hp;
254
Milton Miller837dcfa2005-07-07 17:56:16 -0700255 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
256 return -1;
257
258 if (vtermnos[index] != -1)
259 return -1;
260
will schmidtc3ea6922007-04-18 00:54:51 +1000261 /* make sure no no tty has been registered in this index */
Milton Miller7805b1b2005-07-07 17:56:23 -0700262 hp = hvc_get_by_index(index);
263 if (hp) {
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800264 kref_put(&hp->kref, destroy_hvc_struct);
Milton Miller7805b1b2005-07-07 17:56:23 -0700265 return -1;
266 }
267
Milton Miller837dcfa2005-07-07 17:56:16 -0700268 vtermnos[index] = vtermno;
Milton Miller030ffad2005-07-07 17:56:25 -0700269 cons_ops[index] = ops;
Milton Miller6f248082005-07-07 17:56:17 -0700270
will schmidtc3ea6922007-04-18 00:54:51 +1000271 /* reserve all indices up to and including this index */
Milton Miller6f248082005-07-07 17:56:17 -0700272 if (last_hvc < index)
273 last_hvc = index;
274
Milton Millerd5ee2572005-07-07 17:56:24 -0700275 /* if this index is what the user requested, then register
276 * now (setup won't fail at this point). It's ok to just
277 * call register again if previously .setup failed.
278 */
279 if (index == hvc_con_driver.index)
280 register_console(&hvc_con_driver);
281
Milton Miller837dcfa2005-07-07 17:56:16 -0700282 return 0;
283}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500284EXPORT_SYMBOL_GPL(hvc_instantiate);
Milton Miller837dcfa2005-07-07 17:56:16 -0700285
286/* Wake the sleeping khvcd */
Christian Borntraeger611e0972008-06-20 15:24:08 +0200287void hvc_kick(void)
Milton Miller837dcfa2005-07-07 17:56:16 -0700288{
289 hvc_kicked = 1;
290 wake_up_process(hvc_task);
291}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500292EXPORT_SYMBOL_GPL(hvc_kick);
Milton Miller837dcfa2005-07-07 17:56:16 -0700293
Milton Miller837dcfa2005-07-07 17:56:16 -0700294static void hvc_unthrottle(struct tty_struct *tty)
295{
296 hvc_kick();
297}
298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299/*
300 * The TTY interface won't be used until after the vio layer has exposed the vty
301 * adapter to the kernel.
302 */
303static int hvc_open(struct tty_struct *tty, struct file * filp)
304{
305 struct hvc_struct *hp;
306 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 int rc = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800309 /* Auto increments kref reference if found. */
Olof Johansson87fd7722006-09-07 15:18:08 -0500310 if (!(hp = hvc_get_by_index(tty->index)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312
313 spin_lock_irqsave(&hp->lock, flags);
314 /* Check and then increment for fast path open. */
315 if (hp->count++ > 0) {
Amit Shahe74d0982010-03-12 11:53:15 +0530316 tty_kref_get(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 spin_unlock_irqrestore(&hp->lock, flags);
318 hvc_kick();
319 return 0;
320 } /* else count == 0 */
321
322 tty->driver_data = hp;
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500323
Amit Shahe74d0982010-03-12 11:53:15 +0530324 hp->tty = tty_kref_get(tty);
Christian Borntraeger611e0972008-06-20 15:24:08 +0200325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 spin_unlock_irqrestore(&hp->lock, flags);
Christian Borntraeger611e0972008-06-20 15:24:08 +0200327
Christian Borntraegerb1b135c2008-08-07 09:18:34 +0200328 if (hp->ops->notifier_add)
329 rc = hp->ops->notifier_add(hp, hp->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330
331 /*
Christian Borntraeger611e0972008-06-20 15:24:08 +0200332 * If the notifier fails we return an error. The tty layer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 * will call hvc_close() after a failed open but we don't want to clean
334 * up there so we'll clean up here and clear out the previously set
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800335 * tty fields and return the kref reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 */
337 if (rc) {
338 spin_lock_irqsave(&hp->lock, flags);
339 hp->tty = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 spin_unlock_irqrestore(&hp->lock, flags);
Amit Shahe74d0982010-03-12 11:53:15 +0530341 tty_kref_put(tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 tty->driver_data = NULL;
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800343 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
345 }
346 /* Force wakeup of the polling thread */
347 hvc_kick();
348
349 return rc;
350}
351
352static void hvc_close(struct tty_struct *tty, struct file * filp)
353{
354 struct hvc_struct *hp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 unsigned long flags;
356
357 if (tty_hung_up_p(filp))
358 return;
359
360 /*
361 * No driver_data means that this close was issued after a failed
362 * hvc_open by the tty layer's release_dev() function and we can just
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800363 * exit cleanly because the kref reference wasn't made.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 */
365 if (!tty->driver_data)
366 return;
367
368 hp = tty->driver_data;
Amit Shahe74d0982010-03-12 11:53:15 +0530369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 spin_lock_irqsave(&hp->lock, flags);
371
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 if (--hp->count == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 /* We are done with the tty pointer now. */
374 hp->tty = NULL;
375 spin_unlock_irqrestore(&hp->lock, flags);
376
Christian Borntraegereef26222008-10-12 21:51:31 +0000377 if (hp->ops->notifier_del)
378 hp->ops->notifier_del(hp, hp->data);
379
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000380 /* cancel pending tty resize work */
381 cancel_work_sync(&hp->tty_resize);
382
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 /*
384 * Chain calls chars_in_buffer() and returns immediately if
385 * there is no buffered data otherwise sleeps on a wait queue
386 * waking periodically to check chars_in_buffer().
387 */
388 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 } else {
390 if (hp->count < 0)
391 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
392 hp->vtermno, hp->count);
393 spin_unlock_irqrestore(&hp->lock, flags);
394 }
395
Amit Shahe74d0982010-03-12 11:53:15 +0530396 tty_kref_put(tty);
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800397 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398}
399
400static void hvc_hangup(struct tty_struct *tty)
401{
402 struct hvc_struct *hp = tty->driver_data;
403 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 int temp_open_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405
406 if (!hp)
407 return;
408
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000409 /* cancel pending tty resize work */
410 cancel_work_sync(&hp->tty_resize);
411
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 spin_lock_irqsave(&hp->lock, flags);
413
414 /*
415 * The N_TTY line discipline has problems such that in a close vs
416 * open->hangup case this can be called after the final close so prevent
417 * that from happening for now.
418 */
419 if (hp->count <= 0) {
420 spin_unlock_irqrestore(&hp->lock, flags);
421 return;
422 }
423
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 temp_open_count = hp->count;
425 hp->count = 0;
426 hp->n_outbuf = 0;
427 hp->tty = NULL;
Christian Borntraeger611e0972008-06-20 15:24:08 +0200428
Christian Borntraegereef26222008-10-12 21:51:31 +0000429 spin_unlock_irqrestore(&hp->lock, flags);
430
Hendrik Bruecknerfc362e22008-10-13 23:12:48 +0000431 if (hp->ops->notifier_hangup)
Amit Shahe74d0982010-03-12 11:53:15 +0530432 hp->ops->notifier_hangup(hp, hp->data);
Christian Borntraeger611e0972008-06-20 15:24:08 +0200433
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 while(temp_open_count) {
435 --temp_open_count;
Amit Shahe74d0982010-03-12 11:53:15 +0530436 tty_kref_put(tty);
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800437 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 }
439}
440
441/*
442 * Push buffered characters whether they were just recently buffered or waiting
443 * on a blocked hypervisor. Call this function with hp->lock held.
444 */
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000445static int hvc_push(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446{
447 int n;
448
Milton Miller030ffad2005-07-07 17:56:25 -0700449 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 if (n <= 0) {
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200451 if (n == 0) {
452 hp->do_wakeup = 1;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000453 return 0;
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200454 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 /* throw away output on error; this happens when
456 there is no session connected to the vterm. */
457 hp->n_outbuf = 0;
458 } else
459 hp->n_outbuf -= n;
460 if (hp->n_outbuf > 0)
461 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
462 else
463 hp->do_wakeup = 1;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000464
465 return n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466}
467
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200468static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469{
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200470 struct hvc_struct *hp = tty->driver_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 unsigned long flags;
472 int rsize, written = 0;
473
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200474 /* This write was probably executed during a tty close. */
475 if (!hp)
476 return -EPIPE;
477
478 if (hp->count <= 0)
479 return -EIO;
480
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 spin_lock_irqsave(&hp->lock, flags);
482
483 /* Push pending writes */
484 if (hp->n_outbuf > 0)
485 hvc_push(hp);
486
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000487 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 if (rsize > count)
489 rsize = count;
490 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
491 count -= rsize;
492 buf += rsize;
493 hp->n_outbuf += rsize;
494 written += rsize;
495 hvc_push(hp);
496 }
497 spin_unlock_irqrestore(&hp->lock, flags);
498
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 /*
500 * Racy, but harmless, kick thread if there is still pending data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 */
502 if (hp->n_outbuf)
503 hvc_kick();
504
505 return written;
506}
507
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000508/**
509 * hvc_set_winsz() - Resize the hvc tty terminal window.
510 * @work: work structure.
511 *
512 * The routine shall not be called within an atomic context because it
513 * might sleep.
514 *
515 * Locking: hp->lock
516 */
517static void hvc_set_winsz(struct work_struct *work)
518{
519 struct hvc_struct *hp;
520 unsigned long hvc_flags;
521 struct tty_struct *tty;
522 struct winsize ws;
523
524 hp = container_of(work, struct hvc_struct, tty_resize);
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000525
526 spin_lock_irqsave(&hp->lock, hvc_flags);
527 if (!hp->tty) {
528 spin_unlock_irqrestore(&hp->lock, hvc_flags);
529 return;
530 }
531 ws = hp->ws;
532 tty = tty_kref_get(hp->tty);
533 spin_unlock_irqrestore(&hp->lock, hvc_flags);
534
Alan Coxfc6f6232009-01-02 13:43:17 +0000535 tty_do_resize(tty, &ws);
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000536 tty_kref_put(tty);
537}
538
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539/*
540 * This is actually a contract between the driver and the tty layer outlining
will schmidtc3ea6922007-04-18 00:54:51 +1000541 * how much write room the driver can guarantee will be sent OR BUFFERED. This
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 * driver MUST honor the return value.
543 */
544static int hvc_write_room(struct tty_struct *tty)
545{
546 struct hvc_struct *hp = tty->driver_data;
547
548 if (!hp)
549 return -1;
550
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000551 return hp->outbuf_size - hp->n_outbuf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552}
553
554static int hvc_chars_in_buffer(struct tty_struct *tty)
555{
556 struct hvc_struct *hp = tty->driver_data;
557
558 if (!hp)
Alan Cox23198fd2009-07-20 16:05:27 +0100559 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 return hp->n_outbuf;
561}
562
Will Schmidtb7910722007-04-18 00:44:46 +1000563/*
564 * timeout will vary between the MIN and MAX values defined here. By default
565 * and during console activity we will use a default MIN_TIMEOUT of 10. When
566 * the console is idle, we increase the timeout value on each pass through
567 * msleep until we reach the max. This may be noticeable as a brief (average
568 * one second) delay on the console before the console responds to input when
569 * there has been no input for some time.
570 */
571#define MIN_TIMEOUT (10)
572#define MAX_TIMEOUT (2000)
573static u32 timeout = MIN_TIMEOUT;
574
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575#define HVC_POLL_READ 0x00000001
576#define HVC_POLL_WRITE 0x00000002
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577
Christian Borntraeger611e0972008-06-20 15:24:08 +0200578int hvc_poll(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579{
580 struct tty_struct *tty;
581 int i, n, poll_mask = 0;
582 char buf[N_INBUF] __ALIGNED__;
583 unsigned long flags;
584 int read_total = 0;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000585 int written_total = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
587 spin_lock_irqsave(&hp->lock, flags);
588
589 /* Push pending writes */
590 if (hp->n_outbuf > 0)
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000591 written_total = hvc_push(hp);
Michael Ellermanb5374462006-06-07 17:10:03 +1000592
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 /* Reschedule us if still some write pending */
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000594 if (hp->n_outbuf > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 poll_mask |= HVC_POLL_WRITE;
Hendrik Brueckner3feebbb2008-10-13 23:12:50 +0000596 /* If hvc_push() was not able to write, sleep a few msecs */
597 timeout = (written_total) ? 0 : MIN_TIMEOUT;
598 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599
600 /* No tty attached, just skip */
Amit Shahe74d0982010-03-12 11:53:15 +0530601 tty = tty_kref_get(hp->tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 if (tty == NULL)
603 goto bail;
604
605 /* Now check if we can get data (are we throttled ?) */
606 if (test_bit(TTY_THROTTLED, &tty->flags))
607 goto throttled;
608
Christian Borntraeger611e0972008-06-20 15:24:08 +0200609 /* If we aren't notifier driven and aren't throttled, we always
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 * request a reschedule
611 */
Christian Borntraeger611e0972008-06-20 15:24:08 +0200612 if (!hp->irq_requested)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 poll_mask |= HVC_POLL_READ;
614
615 /* Read data if any */
616 for (;;) {
Alan Cox33f0f882006-01-09 20:54:13 -0800617 int count = tty_buffer_request_room(tty, N_INBUF);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
619 /* If flip is full, just reschedule a later read */
620 if (count == 0) {
621 poll_mask |= HVC_POLL_READ;
622 break;
623 }
624
Milton Miller030ffad2005-07-07 17:56:25 -0700625 n = hp->ops->get_chars(hp->vtermno, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 if (n <= 0) {
627 /* Hangup the tty when disconnected from host */
628 if (n == -EPIPE) {
629 spin_unlock_irqrestore(&hp->lock, flags);
630 tty_hangup(tty);
631 spin_lock_irqsave(&hp->lock, flags);
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200632 } else if ( n == -EAGAIN ) {
633 /*
634 * Some back-ends can only ensure a certain min
635 * num of bytes read, which may be > 'count'.
636 * Let the tty clear the flip buff to make room.
637 */
638 poll_mask |= HVC_POLL_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 }
640 break;
641 }
642 for (i = 0; i < n; ++i) {
643#ifdef CONFIG_MAGIC_SYSRQ
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700644 if (hp->index == hvc_con_driver.index) {
645 /* Handle the SysRq Hack */
646 /* XXX should support a sequence */
647 if (buf[i] == '\x0f') { /* ^O */
Hendrik Brueckner368c1e32008-12-16 00:09:38 +0000648 /* if ^O is pressed again, reset
649 * sysrq_pressed and flip ^O char */
650 sysrq_pressed = !sysrq_pressed;
651 if (sysrq_pressed)
652 continue;
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700653 } else if (sysrq_pressed) {
David Howells7d12e782006-10-05 14:55:46 +0100654 handle_sysrq(buf[i], tty);
Milton Miller2b9e0ba2005-07-07 17:56:19 -0700655 sysrq_pressed = 0;
656 continue;
657 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 }
659#endif /* CONFIG_MAGIC_SYSRQ */
660 tty_insert_flip_char(tty, buf[i], 0);
661 }
662
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 read_total += n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 }
665 throttled:
666 /* Wakeup write queue if necessary */
667 if (hp->do_wakeup) {
668 hp->do_wakeup = 0;
669 tty_wakeup(tty);
670 }
671 bail:
672 spin_unlock_irqrestore(&hp->lock, flags);
673
Will Schmidtb7910722007-04-18 00:44:46 +1000674 if (read_total) {
675 /* Activity is occurring, so reset the polling backoff value to
676 a minimum for performance. */
677 timeout = MIN_TIMEOUT;
678
Michal Ostrowskifb5c5942006-02-18 09:29:59 -0500679 tty_flip_buffer_push(tty);
Will Schmidtb7910722007-04-18 00:44:46 +1000680 }
Amit Shahe74d0982010-03-12 11:53:15 +0530681 if (tty)
682 tty_kref_put(tty);
Will Schmidtb7910722007-04-18 00:44:46 +1000683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 return poll_mask;
685}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500686EXPORT_SYMBOL_GPL(hvc_poll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000688/**
Hendrik Brueckner254be492009-08-27 01:45:39 +0000689 * __hvc_resize() - Update terminal window size information.
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000690 * @hp: HVC console pointer
691 * @ws: Terminal window size structure
692 *
693 * Stores the specified window size information in the hvc structure of @hp.
694 * The function schedule the tty resize update.
695 *
696 * Locking: Locking free; the function MUST be called holding hp->lock
697 */
Hendrik Brueckner254be492009-08-27 01:45:39 +0000698void __hvc_resize(struct hvc_struct *hp, struct winsize ws)
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000699{
Hendrik Brueckner7947cf02008-11-18 01:28:28 +0000700 hp->ws = ws;
701 schedule_work(&hp->tty_resize);
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000702}
Hendrik Brueckner254be492009-08-27 01:45:39 +0000703EXPORT_SYMBOL_GPL(__hvc_resize);
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000704
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705/*
706 * This kthread is either polling or interrupt driven. This is determined by
707 * calling hvc_poll() who determines whether a console adapter support
708 * interrupts.
709 */
Adrian Bunk5605d4d2007-07-09 11:37:38 -0700710static int khvcd(void *unused)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711{
712 int poll_mask;
713 struct hvc_struct *hp;
714
Rafael J. Wysocki83144182007-07-17 04:03:35 -0700715 set_freezable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 __set_current_state(TASK_RUNNING);
717 do {
718 poll_mask = 0;
719 hvc_kicked = 0;
Andrew Mortonb64074e2006-09-16 12:15:38 -0700720 try_to_freeze();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 wmb();
Michael Ellerman1c8950f2008-05-08 14:27:17 +1000722 if (!cpus_are_in_xmon()) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 spin_lock(&hvc_structs_lock);
724 list_for_each_entry(hp, &hvc_structs, next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 poll_mask |= hvc_poll(hp);
726 }
727 spin_unlock(&hvc_structs_lock);
728 } else
729 poll_mask |= HVC_POLL_READ;
730 if (hvc_kicked)
731 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 set_current_state(TASK_INTERRUPTIBLE);
733 if (!hvc_kicked) {
734 if (poll_mask == 0)
735 schedule();
Will Schmidtb7910722007-04-18 00:44:46 +1000736 else {
737 if (timeout < MAX_TIMEOUT)
738 timeout += (timeout >> 6) + 1;
739
740 msleep_interruptible(timeout);
741 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 }
743 __set_current_state(TASK_RUNNING);
744 } while (!kthread_should_stop());
745
746 return 0;
747}
748
Jeff Dikeb68e31d2006-10-02 02:17:18 -0700749static const struct tty_operations hvc_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 .open = hvc_open,
751 .close = hvc_close,
752 .write = hvc_write,
753 .hangup = hvc_hangup,
754 .unthrottle = hvc_unthrottle,
755 .write_room = hvc_write_room,
756 .chars_in_buffer = hvc_chars_in_buffer,
757};
758
Amit Shah119ea102010-01-18 03:44:58 +0000759struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
760 const struct hv_ops *ops,
761 int outbuf_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762{
763 struct hvc_struct *hp;
Milton Miller6f248082005-07-07 17:56:17 -0700764 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700766 /* We wait until a driver actually comes along */
767 if (!hvc_driver) {
768 int err = hvc_init();
769 if (err)
770 return ERR_PTR(err);
771 }
772
Milton Miller2da75822009-01-08 02:14:28 +0000773 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000774 GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 if (!hp)
Milton Milleracad9552005-07-07 17:56:24 -0700776 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
Milton Milleracad9552005-07-07 17:56:24 -0700778 hp->vtermno = vtermno;
Christian Borntraeger611e0972008-06-20 15:24:08 +0200779 hp->data = data;
Milton Miller030ffad2005-07-07 17:56:25 -0700780 hp->ops = ops;
Stephen Rothwell4e9e95a2006-07-13 18:53:32 +1000781 hp->outbuf_size = outbuf_size;
782 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800784 kref_init(&hp->kref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785
Hendrik Bruecknerfebde372008-10-14 05:02:09 +0000786 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 spin_lock_init(&hp->lock);
788 spin_lock(&hvc_structs_lock);
Milton Miller6f248082005-07-07 17:56:17 -0700789
790 /*
791 * find index to use:
792 * see if this vterm id matches one registered for console.
793 */
794 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
Ryan S. Arnold45d607e2006-03-27 21:25:16 +0200795 if (vtermnos[i] == hp->vtermno &&
796 cons_ops[i] == hp->ops)
Milton Miller6f248082005-07-07 17:56:17 -0700797 break;
798
799 /* no matching slot, just use a counter */
800 if (i >= MAX_NR_HVC_CONSOLES)
801 i = ++last_hvc;
802
803 hp->index = i;
804
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 list_add_tail(&(hp->next), &hvc_structs);
806 spin_unlock(&hvc_structs_lock);
807
Milton Milleracad9552005-07-07 17:56:24 -0700808 return hp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809}
Christian Borntraeger7721c492008-07-25 12:06:06 -0500810EXPORT_SYMBOL_GPL(hvc_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811
Hendrik Brueckner934752d2008-10-13 23:12:52 +0000812int hvc_remove(struct hvc_struct *hp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 struct tty_struct *tty;
816
817 spin_lock_irqsave(&hp->lock, flags);
Amit Shahe74d0982010-03-12 11:53:15 +0530818 tty = tty_kref_get(hp->tty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819
820 if (hp->index < MAX_NR_HVC_CONSOLES)
821 vtermnos[hp->index] = -1;
822
823 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
824
825 spin_unlock_irqrestore(&hp->lock, flags);
826
827 /*
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800828 * We 'put' the instance that was grabbed when the kref instance
829 * was initialized using kref_init(). Let the last holder of this
Amit Shahe74d0982010-03-12 11:53:15 +0530830 * kref cause it to be removed, which will probably be the tty_vhangup
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 * below.
832 */
Greg Kroah-Hartman12b20de2007-11-28 10:46:22 -0800833 kref_put(&hp->kref, destroy_hvc_struct);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834
835 /*
Amit Shahe74d0982010-03-12 11:53:15 +0530836 * This function call will auto chain call hvc_hangup.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 */
Amit Shahe74d0982010-03-12 11:53:15 +0530838 if (tty) {
839 tty_vhangup(tty);
840 tty_kref_put(tty);
841 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 return 0;
843}
Amit Shahc0cefeb2009-11-27 20:50:49 +0000844EXPORT_SYMBOL_GPL(hvc_remove);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700846/* Driver initialization: called as soon as someone uses hvc_alloc(). */
847static int hvc_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848{
Michael Neuling55aab8c2006-03-25 17:30:00 +1100849 struct tty_driver *drv;
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700850 int err;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100851
Milton Miller5f6d9c02005-07-07 17:56:21 -0700852 /* We need more than hvc_count adapters due to hotplug additions. */
Michael Neuling55aab8c2006-03-25 17:30:00 +1100853 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700854 if (!drv) {
855 err = -ENOMEM;
856 goto out;
857 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858
Michael Neuling55aab8c2006-03-25 17:30:00 +1100859 drv->owner = THIS_MODULE;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100860 drv->driver_name = "hvc";
861 drv->name = "hvc";
862 drv->major = HVC_MAJOR;
863 drv->minor_start = HVC_MINOR;
864 drv->type = TTY_DRIVER_TYPE_SYSTEM;
865 drv->init_termios = tty_std_termios;
Hendrik Brueckner56ce9e22008-10-13 23:12:49 +0000866 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
Michael Neuling55aab8c2006-03-25 17:30:00 +1100867 tty_set_operations(drv, &hvc_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 /* Always start the kthread because there can be hotplug vty adapters
870 * added later. */
871 hvc_task = kthread_run(khvcd, NULL, "khvcd");
872 if (IS_ERR(hvc_task)) {
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700873 printk(KERN_ERR "Couldn't create kthread for console.\n");
874 err = PTR_ERR(hvc_task);
875 goto put_tty;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 }
877
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700878 err = tty_register_driver(drv);
879 if (err) {
880 printk(KERN_ERR "Couldn't register hvc console driver\n");
881 goto stop_thread;
882 }
Anton Blanchardef4cbee2005-09-14 14:19:18 -0700883
Milton Miller9fef3d22009-01-08 02:14:18 +0000884 /*
885 * Make sure tty is fully registered before allowing it to be
886 * found by hvc_console_device.
887 */
888 smp_mb();
Michael Neuling55aab8c2006-03-25 17:30:00 +1100889 hvc_driver = drv;
Milton Milleracad9552005-07-07 17:56:24 -0700890 return 0;
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700891
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700892stop_thread:
893 kthread_stop(hvc_task);
894 hvc_task = NULL;
Julia Lawall2571cd6a2008-10-13 10:31:49 +0100895put_tty:
896 put_tty_driver(drv);
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700897out:
898 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899}
900
will schmidtc3ea6922007-04-18 00:54:51 +1000901/* This isn't particularly necessary due to this being a console driver
Milton Miller320da0d2005-07-07 17:56:20 -0700902 * but it is nice to be thorough.
903 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904static void __exit hvc_exit(void)
905{
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700906 if (hvc_driver) {
907 kthread_stop(hvc_task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908
Rusty Russell3e6c6f62007-10-16 23:30:13 -0700909 tty_unregister_driver(hvc_driver);
910 /* return tty_struct instances allocated in hvc_init(). */
911 put_tty_driver(hvc_driver);
912 unregister_console(&hvc_con_driver);
913 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915module_exit(hvc_exit);