Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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> | |
1da177e4 LT |
30 | #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> | |
7dfb7103 | 40 | #include <linux/freezer.h> |
45d607ed | 41 | |
1da177e4 | 42 | #include <asm/uaccess.h> |
45d607ed RA |
43 | |
44 | #include "hvc_console.h" | |
1da177e4 LT |
45 | |
46 | #define HVC_MAJOR 229 | |
47 | #define HVC_MINOR 0 | |
48 | ||
1da177e4 LT |
49 | /* |
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 | /* | |
45d607ed RA |
56 | * 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. | |
1da177e4 | 59 | */ |
1da177e4 LT |
60 | #define N_OUTBUF 16 |
61 | #define N_INBUF 16 | |
62 | ||
45d607ed | 63 | #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
1da177e4 | 64 | |
837dcfaf MM |
65 | static struct tty_driver *hvc_driver; |
66 | static struct task_struct *hvc_task; | |
67 | ||
68 | /* Picks up late kicks after list walk but before schedule() */ | |
69 | static int hvc_kicked; | |
70 | ||
3e6c6f63 RR |
71 | static int hvc_init(void); |
72 | ||
837dcfaf MM |
73 | #ifdef CONFIG_MAGIC_SYSRQ |
74 | static int sysrq_pressed; | |
75 | #endif | |
76 | ||
1da177e4 | 77 | /* dynamic list of hvc_struct instances */ |
bed9759b | 78 | static LIST_HEAD(hvc_structs); |
1da177e4 LT |
79 | |
80 | /* | |
81 | * Protect the list of hvc_struct instances from inserts and removals during | |
82 | * list traversal. | |
83 | */ | |
84 | static DEFINE_SPINLOCK(hvc_structs_lock); | |
85 | ||
837dcfaf | 86 | /* |
6f24808e MM |
87 | * 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 | |
c3ea6921 | 89 | * a console candidate registered with hvc_instantiate(). |
837dcfaf | 90 | */ |
6f24808e | 91 | static int last_hvc = -1; |
837dcfaf MM |
92 | |
93 | /* | |
c3ea6921 | 94 | * Do not call this function with either the hvc_structs_lock or the hvc_struct |
12b20ded | 95 | * lock held. If successful, this function increments the kref reference |
837dcfaf MM |
96 | * count against the target hvc_struct so it should be released when finished. |
97 | */ | |
4fa156ea | 98 | static struct hvc_struct *hvc_get_by_index(int index) |
837dcfaf MM |
99 | { |
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) { | |
12b20ded | 108 | kref_get(&hp->kref); |
837dcfaf MM |
109 | 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 | ||
121 | ||
1da177e4 LT |
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 | */ | |
b5113068 | 128 | static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
64e4da57 MM |
129 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
130 | {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; | |
1da177e4 | 131 | |
837dcfaf MM |
132 | /* |
133 | * Console APIs, NOT TTY. These APIs are available immediately when | |
134 | * hvc_console_setup() finds adapters. | |
135 | */ | |
136 | ||
4fa156ea AB |
137 | static void hvc_console_print(struct console *co, const char *b, |
138 | unsigned count) | |
837dcfaf | 139 | { |
45d607ed | 140 | char c[N_OUTBUF] __ALIGNED__; |
837dcfaf | 141 | unsigned i = 0, n = 0; |
030ffad2 | 142 | int r, donecr = 0, index = co->index; |
837dcfaf MM |
143 | |
144 | /* Console access attempt outside of acceptable console range. */ | |
030ffad2 | 145 | if (index >= MAX_NR_HVC_CONSOLES) |
837dcfaf MM |
146 | return; |
147 | ||
c3ea6921 | 148 | /* This console adapter was removed so it is not usable. */ |
ecfcbee7 | 149 | if (vtermnos[index] == -1) |
837dcfaf MM |
150 | 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 { | |
030ffad2 | 163 | r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
3feebbb5 | 164 | if (r <= 0) { |
837dcfaf MM |
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 | ||
176 | static struct tty_driver *hvc_console_device(struct console *c, int *index) | |
177 | { | |
7805b1b2 MM |
178 | if (vtermnos[c->index] == -1) |
179 | return NULL; | |
180 | ||
837dcfaf MM |
181 | *index = c->index; |
182 | return hvc_driver; | |
183 | } | |
184 | ||
185 | static int __init hvc_console_setup(struct console *co, char *options) | |
186 | { | |
7805b1b2 MM |
187 | if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
188 | return -ENODEV; | |
189 | ||
190 | if (vtermnos[co->index] == -1) | |
191 | return -ENODEV; | |
192 | ||
837dcfaf MM |
193 | return 0; |
194 | } | |
195 | ||
4fa156ea | 196 | static struct console hvc_con_driver = { |
837dcfaf MM |
197 | .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 | ||
d5ee257c | 205 | /* |
c3ea6921 | 206 | * Early console initialization. Precedes driver initialization. |
d5ee257c MM |
207 | * |
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 | */ | |
837dcfaf MM |
220 | static int __init hvc_console_init(void) |
221 | { | |
837dcfaf MM |
222 | register_console(&hvc_con_driver); |
223 | return 0; | |
224 | } | |
225 | console_initcall(hvc_console_init); | |
1da177e4 | 226 | |
12b20ded GKH |
227 | /* callback when the kboject ref count reaches zero. */ |
228 | static 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 | ||
1da177e4 | 244 | /* |
6f24808e MM |
245 | * 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. | |
1da177e4 | 249 | */ |
b5113068 | 250 | int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) |
837dcfaf | 251 | { |
7805b1b2 MM |
252 | struct hvc_struct *hp; |
253 | ||
837dcfaf MM |
254 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
255 | return -1; | |
1da177e4 | 256 | |
837dcfaf MM |
257 | if (vtermnos[index] != -1) |
258 | return -1; | |
259 | ||
c3ea6921 | 260 | /* make sure no no tty has been registered in this index */ |
7805b1b2 MM |
261 | hp = hvc_get_by_index(index); |
262 | if (hp) { | |
12b20ded | 263 | kref_put(&hp->kref, destroy_hvc_struct); |
7805b1b2 MM |
264 | return -1; |
265 | } | |
266 | ||
837dcfaf | 267 | vtermnos[index] = vtermno; |
030ffad2 | 268 | cons_ops[index] = ops; |
6f24808e | 269 | |
c3ea6921 | 270 | /* reserve all indices up to and including this index */ |
6f24808e MM |
271 | if (last_hvc < index) |
272 | last_hvc = index; | |
273 | ||
d5ee257c MM |
274 | /* 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 | ||
837dcfaf MM |
281 | return 0; |
282 | } | |
7721c494 | 283 | EXPORT_SYMBOL_GPL(hvc_instantiate); |
1da177e4 LT |
284 | |
285 | /* Wake the sleeping khvcd */ | |
611e097d | 286 | void hvc_kick(void) |
1da177e4 LT |
287 | { |
288 | hvc_kicked = 1; | |
289 | wake_up_process(hvc_task); | |
290 | } | |
7721c494 | 291 | EXPORT_SYMBOL_GPL(hvc_kick); |
1da177e4 | 292 | |
1da177e4 LT |
293 | static void hvc_unthrottle(struct tty_struct *tty) |
294 | { | |
295 | hvc_kick(); | |
296 | } | |
297 | ||
1da177e4 LT |
298 | /* |
299 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
300 | * adapter to the kernel. | |
301 | */ | |
302 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
303 | { | |
304 | struct hvc_struct *hp; | |
305 | unsigned long flags; | |
1da177e4 | 306 | int rc = 0; |
1da177e4 | 307 | |
12b20ded | 308 | /* Auto increments kref reference if found. */ |
87fd7724 | 309 | if (!(hp = hvc_get_by_index(tty->index))) |
1da177e4 | 310 | return -ENODEV; |
1da177e4 LT |
311 | |
312 | spin_lock_irqsave(&hp->lock, flags); | |
313 | /* Check and then increment for fast path open. */ | |
314 | if (hp->count++ > 0) { | |
e74d098c | 315 | tty_kref_get(tty); |
1da177e4 LT |
316 | spin_unlock_irqrestore(&hp->lock, flags); |
317 | hvc_kick(); | |
318 | return 0; | |
319 | } /* else count == 0 */ | |
320 | ||
321 | tty->driver_data = hp; | |
fb5c594c | 322 | |
e74d098c | 323 | hp->tty = tty_kref_get(tty); |
611e097d | 324 | |
1da177e4 | 325 | spin_unlock_irqrestore(&hp->lock, flags); |
611e097d | 326 | |
b1b135c8 CB |
327 | if (hp->ops->notifier_add) |
328 | rc = hp->ops->notifier_add(hp, hp->data); | |
1da177e4 LT |
329 | |
330 | /* | |
611e097d | 331 | * If the notifier fails we return an error. The tty layer |
1da177e4 LT |
332 | * 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 | |
12b20ded | 334 | * tty fields and return the kref reference. |
1da177e4 LT |
335 | */ |
336 | if (rc) { | |
337 | spin_lock_irqsave(&hp->lock, flags); | |
338 | hp->tty = NULL; | |
1da177e4 | 339 | spin_unlock_irqrestore(&hp->lock, flags); |
e74d098c | 340 | tty_kref_put(tty); |
1da177e4 | 341 | tty->driver_data = NULL; |
12b20ded | 342 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
343 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); |
344 | } | |
345 | /* Force wakeup of the polling thread */ | |
346 | hvc_kick(); | |
347 | ||
348 | return rc; | |
349 | } | |
350 | ||
351 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
352 | { | |
353 | struct hvc_struct *hp; | |
1da177e4 LT |
354 | unsigned long flags; |
355 | ||
356 | if (tty_hung_up_p(filp)) | |
357 | return; | |
358 | ||
359 | /* | |
360 | * No driver_data means that this close was issued after a failed | |
361 | * hvc_open by the tty layer's release_dev() function and we can just | |
12b20ded | 362 | * exit cleanly because the kref reference wasn't made. |
1da177e4 LT |
363 | */ |
364 | if (!tty->driver_data) | |
365 | return; | |
366 | ||
367 | hp = tty->driver_data; | |
e74d098c | 368 | |
1da177e4 | 369 | spin_lock_irqsave(&hp->lock, flags); |
e74d098c | 370 | tty_kref_get(tty); |
1da177e4 | 371 | |
1da177e4 | 372 | if (--hp->count == 0) { |
1da177e4 LT |
373 | /* We are done with the tty pointer now. */ |
374 | hp->tty = NULL; | |
375 | spin_unlock_irqrestore(&hp->lock, flags); | |
376 | ||
e74d098c AS |
377 | /* Put the ref obtained in hvc_open() */ |
378 | tty_kref_put(tty); | |
379 | ||
eef2622a CB |
380 | if (hp->ops->notifier_del) |
381 | hp->ops->notifier_del(hp, hp->data); | |
382 | ||
febde371 HB |
383 | /* cancel pending tty resize work */ |
384 | cancel_work_sync(&hp->tty_resize); | |
385 | ||
1da177e4 LT |
386 | /* |
387 | * Chain calls chars_in_buffer() and returns immediately if | |
388 | * there is no buffered data otherwise sleeps on a wait queue | |
389 | * waking periodically to check chars_in_buffer(). | |
390 | */ | |
391 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
1da177e4 LT |
392 | } else { |
393 | if (hp->count < 0) | |
394 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
395 | hp->vtermno, hp->count); | |
396 | spin_unlock_irqrestore(&hp->lock, flags); | |
397 | } | |
398 | ||
e74d098c | 399 | tty_kref_put(tty); |
12b20ded | 400 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
401 | } |
402 | ||
403 | static void hvc_hangup(struct tty_struct *tty) | |
404 | { | |
405 | struct hvc_struct *hp = tty->driver_data; | |
406 | unsigned long flags; | |
1da177e4 | 407 | int temp_open_count; |
1da177e4 LT |
408 | |
409 | if (!hp) | |
410 | return; | |
411 | ||
febde371 HB |
412 | /* cancel pending tty resize work */ |
413 | cancel_work_sync(&hp->tty_resize); | |
414 | ||
1da177e4 LT |
415 | spin_lock_irqsave(&hp->lock, flags); |
416 | ||
417 | /* | |
418 | * The N_TTY line discipline has problems such that in a close vs | |
419 | * open->hangup case this can be called after the final close so prevent | |
420 | * that from happening for now. | |
421 | */ | |
422 | if (hp->count <= 0) { | |
423 | spin_unlock_irqrestore(&hp->lock, flags); | |
424 | return; | |
425 | } | |
426 | ||
1da177e4 LT |
427 | temp_open_count = hp->count; |
428 | hp->count = 0; | |
429 | hp->n_outbuf = 0; | |
430 | hp->tty = NULL; | |
611e097d | 431 | |
eef2622a CB |
432 | spin_unlock_irqrestore(&hp->lock, flags); |
433 | ||
fc362e2e | 434 | if (hp->ops->notifier_hangup) |
e74d098c | 435 | hp->ops->notifier_hangup(hp, hp->data); |
611e097d | 436 | |
1da177e4 LT |
437 | while(temp_open_count) { |
438 | --temp_open_count; | |
e74d098c | 439 | tty_kref_put(tty); |
12b20ded | 440 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
441 | } |
442 | } | |
443 | ||
444 | /* | |
445 | * Push buffered characters whether they were just recently buffered or waiting | |
446 | * on a blocked hypervisor. Call this function with hp->lock held. | |
447 | */ | |
3feebbb5 | 448 | static int hvc_push(struct hvc_struct *hp) |
1da177e4 LT |
449 | { |
450 | int n; | |
451 | ||
030ffad2 | 452 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 453 | if (n <= 0) { |
45d607ed RA |
454 | if (n == 0) { |
455 | hp->do_wakeup = 1; | |
3feebbb5 | 456 | return 0; |
45d607ed | 457 | } |
1da177e4 LT |
458 | /* throw away output on error; this happens when |
459 | there is no session connected to the vterm. */ | |
460 | hp->n_outbuf = 0; | |
461 | } else | |
462 | hp->n_outbuf -= n; | |
463 | if (hp->n_outbuf > 0) | |
464 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
465 | else | |
466 | hp->do_wakeup = 1; | |
3feebbb5 HB |
467 | |
468 | return n; | |
1da177e4 LT |
469 | } |
470 | ||
45d607ed | 471 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 472 | { |
45d607ed | 473 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
474 | unsigned long flags; |
475 | int rsize, written = 0; | |
476 | ||
45d607ed RA |
477 | /* This write was probably executed during a tty close. */ |
478 | if (!hp) | |
479 | return -EPIPE; | |
480 | ||
481 | if (hp->count <= 0) | |
482 | return -EIO; | |
483 | ||
1da177e4 LT |
484 | spin_lock_irqsave(&hp->lock, flags); |
485 | ||
486 | /* Push pending writes */ | |
487 | if (hp->n_outbuf > 0) | |
488 | hvc_push(hp); | |
489 | ||
4e9e95a3 | 490 | while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { |
1da177e4 LT |
491 | if (rsize > count) |
492 | rsize = count; | |
493 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
494 | count -= rsize; | |
495 | buf += rsize; | |
496 | hp->n_outbuf += rsize; | |
497 | written += rsize; | |
498 | hvc_push(hp); | |
499 | } | |
500 | spin_unlock_irqrestore(&hp->lock, flags); | |
501 | ||
1da177e4 LT |
502 | /* |
503 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
504 | */ |
505 | if (hp->n_outbuf) | |
506 | hvc_kick(); | |
507 | ||
508 | return written; | |
509 | } | |
510 | ||
febde371 HB |
511 | /** |
512 | * hvc_set_winsz() - Resize the hvc tty terminal window. | |
513 | * @work: work structure. | |
514 | * | |
515 | * The routine shall not be called within an atomic context because it | |
516 | * might sleep. | |
517 | * | |
518 | * Locking: hp->lock | |
519 | */ | |
520 | static void hvc_set_winsz(struct work_struct *work) | |
521 | { | |
522 | struct hvc_struct *hp; | |
523 | unsigned long hvc_flags; | |
524 | struct tty_struct *tty; | |
525 | struct winsize ws; | |
526 | ||
527 | hp = container_of(work, struct hvc_struct, tty_resize); | |
febde371 HB |
528 | |
529 | spin_lock_irqsave(&hp->lock, hvc_flags); | |
530 | if (!hp->tty) { | |
531 | spin_unlock_irqrestore(&hp->lock, hvc_flags); | |
532 | return; | |
533 | } | |
534 | ws = hp->ws; | |
535 | tty = tty_kref_get(hp->tty); | |
536 | spin_unlock_irqrestore(&hp->lock, hvc_flags); | |
537 | ||
fc6f6238 | 538 | tty_do_resize(tty, &ws); |
febde371 HB |
539 | tty_kref_put(tty); |
540 | } | |
541 | ||
1da177e4 LT |
542 | /* |
543 | * This is actually a contract between the driver and the tty layer outlining | |
c3ea6921 | 544 | * how much write room the driver can guarantee will be sent OR BUFFERED. This |
1da177e4 LT |
545 | * driver MUST honor the return value. |
546 | */ | |
547 | static int hvc_write_room(struct tty_struct *tty) | |
548 | { | |
549 | struct hvc_struct *hp = tty->driver_data; | |
550 | ||
551 | if (!hp) | |
552 | return -1; | |
553 | ||
4e9e95a3 | 554 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
555 | } |
556 | ||
557 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
558 | { | |
559 | struct hvc_struct *hp = tty->driver_data; | |
560 | ||
561 | if (!hp) | |
23198fda | 562 | return 0; |
1da177e4 LT |
563 | return hp->n_outbuf; |
564 | } | |
565 | ||
b791072b WS |
566 | /* |
567 | * timeout will vary between the MIN and MAX values defined here. By default | |
568 | * and during console activity we will use a default MIN_TIMEOUT of 10. When | |
569 | * the console is idle, we increase the timeout value on each pass through | |
570 | * msleep until we reach the max. This may be noticeable as a brief (average | |
571 | * one second) delay on the console before the console responds to input when | |
572 | * there has been no input for some time. | |
573 | */ | |
574 | #define MIN_TIMEOUT (10) | |
575 | #define MAX_TIMEOUT (2000) | |
576 | static u32 timeout = MIN_TIMEOUT; | |
577 | ||
1da177e4 LT |
578 | #define HVC_POLL_READ 0x00000001 |
579 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 | 580 | |
611e097d | 581 | int hvc_poll(struct hvc_struct *hp) |
1da177e4 LT |
582 | { |
583 | struct tty_struct *tty; | |
584 | int i, n, poll_mask = 0; | |
585 | char buf[N_INBUF] __ALIGNED__; | |
586 | unsigned long flags; | |
587 | int read_total = 0; | |
3feebbb5 | 588 | int written_total = 0; |
1da177e4 LT |
589 | |
590 | spin_lock_irqsave(&hp->lock, flags); | |
591 | ||
592 | /* Push pending writes */ | |
593 | if (hp->n_outbuf > 0) | |
3feebbb5 | 594 | written_total = hvc_push(hp); |
b5374461 | 595 | |
1da177e4 | 596 | /* Reschedule us if still some write pending */ |
3feebbb5 | 597 | if (hp->n_outbuf > 0) { |
1da177e4 | 598 | poll_mask |= HVC_POLL_WRITE; |
3feebbb5 HB |
599 | /* If hvc_push() was not able to write, sleep a few msecs */ |
600 | timeout = (written_total) ? 0 : MIN_TIMEOUT; | |
601 | } | |
1da177e4 LT |
602 | |
603 | /* No tty attached, just skip */ | |
e74d098c | 604 | tty = tty_kref_get(hp->tty); |
1da177e4 LT |
605 | if (tty == NULL) |
606 | goto bail; | |
607 | ||
608 | /* Now check if we can get data (are we throttled ?) */ | |
609 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
610 | goto throttled; | |
611 | ||
611e097d | 612 | /* If we aren't notifier driven and aren't throttled, we always |
1da177e4 LT |
613 | * request a reschedule |
614 | */ | |
611e097d | 615 | if (!hp->irq_requested) |
1da177e4 LT |
616 | poll_mask |= HVC_POLL_READ; |
617 | ||
618 | /* Read data if any */ | |
619 | for (;;) { | |
33f0f88f | 620 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
621 | |
622 | /* If flip is full, just reschedule a later read */ | |
623 | if (count == 0) { | |
624 | poll_mask |= HVC_POLL_READ; | |
625 | break; | |
626 | } | |
627 | ||
030ffad2 | 628 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
629 | if (n <= 0) { |
630 | /* Hangup the tty when disconnected from host */ | |
631 | if (n == -EPIPE) { | |
632 | spin_unlock_irqrestore(&hp->lock, flags); | |
633 | tty_hangup(tty); | |
634 | spin_lock_irqsave(&hp->lock, flags); | |
45d607ed RA |
635 | } else if ( n == -EAGAIN ) { |
636 | /* | |
637 | * Some back-ends can only ensure a certain min | |
638 | * num of bytes read, which may be > 'count'. | |
639 | * Let the tty clear the flip buff to make room. | |
640 | */ | |
641 | poll_mask |= HVC_POLL_READ; | |
1da177e4 LT |
642 | } |
643 | break; | |
644 | } | |
645 | for (i = 0; i < n; ++i) { | |
646 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
647 | if (hp->index == hvc_con_driver.index) { |
648 | /* Handle the SysRq Hack */ | |
649 | /* XXX should support a sequence */ | |
650 | if (buf[i] == '\x0f') { /* ^O */ | |
368c1e32 HB |
651 | /* if ^O is pressed again, reset |
652 | * sysrq_pressed and flip ^O char */ | |
653 | sysrq_pressed = !sysrq_pressed; | |
654 | if (sysrq_pressed) | |
655 | continue; | |
2b9e0bac | 656 | } else if (sysrq_pressed) { |
7d12e780 | 657 | handle_sysrq(buf[i], tty); |
2b9e0bac MM |
658 | sysrq_pressed = 0; |
659 | continue; | |
660 | } | |
1da177e4 LT |
661 | } |
662 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
663 | tty_insert_flip_char(tty, buf[i], 0); | |
664 | } | |
665 | ||
1da177e4 | 666 | read_total += n; |
1da177e4 LT |
667 | } |
668 | throttled: | |
669 | /* Wakeup write queue if necessary */ | |
670 | if (hp->do_wakeup) { | |
671 | hp->do_wakeup = 0; | |
672 | tty_wakeup(tty); | |
673 | } | |
674 | bail: | |
675 | spin_unlock_irqrestore(&hp->lock, flags); | |
676 | ||
b791072b WS |
677 | if (read_total) { |
678 | /* Activity is occurring, so reset the polling backoff value to | |
679 | a minimum for performance. */ | |
680 | timeout = MIN_TIMEOUT; | |
681 | ||
fb5c594c | 682 | tty_flip_buffer_push(tty); |
b791072b | 683 | } |
e74d098c AS |
684 | if (tty) |
685 | tty_kref_put(tty); | |
b791072b | 686 | |
1da177e4 LT |
687 | return poll_mask; |
688 | } | |
7721c494 | 689 | EXPORT_SYMBOL_GPL(hvc_poll); |
1da177e4 | 690 | |
febde371 | 691 | /** |
254be490 | 692 | * __hvc_resize() - Update terminal window size information. |
febde371 HB |
693 | * @hp: HVC console pointer |
694 | * @ws: Terminal window size structure | |
695 | * | |
696 | * Stores the specified window size information in the hvc structure of @hp. | |
697 | * The function schedule the tty resize update. | |
698 | * | |
699 | * Locking: Locking free; the function MUST be called holding hp->lock | |
700 | */ | |
254be490 | 701 | void __hvc_resize(struct hvc_struct *hp, struct winsize ws) |
febde371 | 702 | { |
7947cf0d HB |
703 | hp->ws = ws; |
704 | schedule_work(&hp->tty_resize); | |
febde371 | 705 | } |
254be490 | 706 | EXPORT_SYMBOL_GPL(__hvc_resize); |
febde371 | 707 | |
1da177e4 LT |
708 | /* |
709 | * This kthread is either polling or interrupt driven. This is determined by | |
710 | * calling hvc_poll() who determines whether a console adapter support | |
711 | * interrupts. | |
712 | */ | |
5605d4de | 713 | static int khvcd(void *unused) |
1da177e4 LT |
714 | { |
715 | int poll_mask; | |
716 | struct hvc_struct *hp; | |
717 | ||
83144186 | 718 | set_freezable(); |
1da177e4 LT |
719 | __set_current_state(TASK_RUNNING); |
720 | do { | |
721 | poll_mask = 0; | |
722 | hvc_kicked = 0; | |
b64074e4 | 723 | try_to_freeze(); |
1da177e4 | 724 | wmb(); |
1c8950ff | 725 | if (!cpus_are_in_xmon()) { |
1da177e4 LT |
726 | spin_lock(&hvc_structs_lock); |
727 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
728 | poll_mask |= hvc_poll(hp); |
729 | } | |
730 | spin_unlock(&hvc_structs_lock); | |
731 | } else | |
732 | poll_mask |= HVC_POLL_READ; | |
733 | if (hvc_kicked) | |
734 | continue; | |
1da177e4 LT |
735 | set_current_state(TASK_INTERRUPTIBLE); |
736 | if (!hvc_kicked) { | |
737 | if (poll_mask == 0) | |
738 | schedule(); | |
b791072b WS |
739 | else { |
740 | if (timeout < MAX_TIMEOUT) | |
741 | timeout += (timeout >> 6) + 1; | |
742 | ||
743 | msleep_interruptible(timeout); | |
744 | } | |
1da177e4 LT |
745 | } |
746 | __set_current_state(TASK_RUNNING); | |
747 | } while (!kthread_should_stop()); | |
748 | ||
749 | return 0; | |
750 | } | |
751 | ||
b68e31d0 | 752 | static const struct tty_operations hvc_ops = { |
1da177e4 LT |
753 | .open = hvc_open, |
754 | .close = hvc_close, | |
755 | .write = hvc_write, | |
756 | .hangup = hvc_hangup, | |
757 | .unthrottle = hvc_unthrottle, | |
758 | .write_room = hvc_write_room, | |
759 | .chars_in_buffer = hvc_chars_in_buffer, | |
760 | }; | |
761 | ||
119ea109 AS |
762 | struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, |
763 | const struct hv_ops *ops, | |
764 | int outbuf_size) | |
1da177e4 LT |
765 | { |
766 | struct hvc_struct *hp; | |
6f24808e | 767 | int i; |
1da177e4 | 768 | |
3e6c6f63 RR |
769 | /* We wait until a driver actually comes along */ |
770 | if (!hvc_driver) { | |
771 | int err = hvc_init(); | |
772 | if (err) | |
773 | return ERR_PTR(err); | |
774 | } | |
775 | ||
2da7582f | 776 | hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
4e9e95a3 | 777 | GFP_KERNEL); |
1da177e4 | 778 | if (!hp) |
acad9559 | 779 | return ERR_PTR(-ENOMEM); |
1da177e4 | 780 | |
acad9559 | 781 | hp->vtermno = vtermno; |
611e097d | 782 | hp->data = data; |
030ffad2 | 783 | hp->ops = ops; |
4e9e95a3 SR |
784 | hp->outbuf_size = outbuf_size; |
785 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 | 786 | |
12b20ded | 787 | kref_init(&hp->kref); |
1da177e4 | 788 | |
febde371 | 789 | INIT_WORK(&hp->tty_resize, hvc_set_winsz); |
1da177e4 LT |
790 | spin_lock_init(&hp->lock); |
791 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
792 | |
793 | /* | |
794 | * find index to use: | |
795 | * see if this vterm id matches one registered for console. | |
796 | */ | |
797 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
45d607ed RA |
798 | if (vtermnos[i] == hp->vtermno && |
799 | cons_ops[i] == hp->ops) | |
6f24808e MM |
800 | break; |
801 | ||
802 | /* no matching slot, just use a counter */ | |
803 | if (i >= MAX_NR_HVC_CONSOLES) | |
804 | i = ++last_hvc; | |
805 | ||
806 | hp->index = i; | |
807 | ||
1da177e4 LT |
808 | list_add_tail(&(hp->next), &hvc_structs); |
809 | spin_unlock(&hvc_structs_lock); | |
810 | ||
acad9559 | 811 | return hp; |
1da177e4 | 812 | } |
7721c494 | 813 | EXPORT_SYMBOL_GPL(hvc_alloc); |
1da177e4 | 814 | |
934752d8 | 815 | int hvc_remove(struct hvc_struct *hp) |
1da177e4 | 816 | { |
1da177e4 | 817 | unsigned long flags; |
1da177e4 LT |
818 | struct tty_struct *tty; |
819 | ||
820 | spin_lock_irqsave(&hp->lock, flags); | |
e74d098c | 821 | tty = tty_kref_get(hp->tty); |
1da177e4 LT |
822 | |
823 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
824 | vtermnos[hp->index] = -1; | |
825 | ||
826 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
827 | ||
828 | spin_unlock_irqrestore(&hp->lock, flags); | |
829 | ||
830 | /* | |
12b20ded GKH |
831 | * We 'put' the instance that was grabbed when the kref instance |
832 | * was initialized using kref_init(). Let the last holder of this | |
e74d098c | 833 | * kref cause it to be removed, which will probably be the tty_vhangup |
1da177e4 LT |
834 | * below. |
835 | */ | |
12b20ded | 836 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
837 | |
838 | /* | |
e74d098c | 839 | * This function call will auto chain call hvc_hangup. |
1da177e4 | 840 | */ |
e74d098c AS |
841 | if (tty) { |
842 | tty_vhangup(tty); | |
843 | tty_kref_put(tty); | |
844 | } | |
1da177e4 LT |
845 | return 0; |
846 | } | |
c0cefebc | 847 | EXPORT_SYMBOL_GPL(hvc_remove); |
1da177e4 | 848 | |
3e6c6f63 RR |
849 | /* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
850 | static int hvc_init(void) | |
1da177e4 | 851 | { |
55aab8cd | 852 | struct tty_driver *drv; |
3e6c6f63 | 853 | int err; |
55aab8cd | 854 | |
5f6d9c07 | 855 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd | 856 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
3e6c6f63 RR |
857 | if (!drv) { |
858 | err = -ENOMEM; | |
859 | goto out; | |
860 | } | |
1da177e4 | 861 | |
55aab8cd | 862 | drv->owner = THIS_MODULE; |
55aab8cd MN |
863 | drv->driver_name = "hvc"; |
864 | drv->name = "hvc"; | |
865 | drv->major = HVC_MAJOR; | |
866 | drv->minor_start = HVC_MINOR; | |
867 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
868 | drv->init_termios = tty_std_termios; | |
56ce9e2b | 869 | drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; |
55aab8cd | 870 | tty_set_operations(drv, &hvc_ops); |
1da177e4 | 871 | |
1da177e4 LT |
872 | /* Always start the kthread because there can be hotplug vty adapters |
873 | * added later. */ | |
874 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
875 | if (IS_ERR(hvc_task)) { | |
3e6c6f63 RR |
876 | printk(KERN_ERR "Couldn't create kthread for console.\n"); |
877 | err = PTR_ERR(hvc_task); | |
878 | goto put_tty; | |
1da177e4 LT |
879 | } |
880 | ||
3e6c6f63 RR |
881 | err = tty_register_driver(drv); |
882 | if (err) { | |
883 | printk(KERN_ERR "Couldn't register hvc console driver\n"); | |
884 | goto stop_thread; | |
885 | } | |
ef4cbee0 | 886 | |
9fef3d2d MM |
887 | /* |
888 | * Make sure tty is fully registered before allowing it to be | |
889 | * found by hvc_console_device. | |
890 | */ | |
891 | smp_mb(); | |
55aab8cd | 892 | hvc_driver = drv; |
acad9559 | 893 | return 0; |
3e6c6f63 | 894 | |
3e6c6f63 RR |
895 | stop_thread: |
896 | kthread_stop(hvc_task); | |
897 | hvc_task = NULL; | |
2571cd6a JL |
898 | put_tty: |
899 | put_tty_driver(drv); | |
3e6c6f63 RR |
900 | out: |
901 | return err; | |
1da177e4 LT |
902 | } |
903 | ||
c3ea6921 | 904 | /* This isn't particularly necessary due to this being a console driver |
320da0d2 MM |
905 | * but it is nice to be thorough. |
906 | */ | |
1da177e4 LT |
907 | static void __exit hvc_exit(void) |
908 | { | |
3e6c6f63 RR |
909 | if (hvc_driver) { |
910 | kthread_stop(hvc_task); | |
1da177e4 | 911 | |
3e6c6f63 RR |
912 | tty_unregister_driver(hvc_driver); |
913 | /* return tty_struct instances allocated in hvc_init(). */ | |
914 | put_tty_driver(hvc_driver); | |
915 | unregister_console(&hvc_con_driver); | |
916 | } | |
1da177e4 | 917 | } |
1da177e4 | 918 | module_exit(hvc_exit); |