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> |
5a0e3ad6 | 41 | #include <linux/slab.h> |
45d607ed | 42 | |
1da177e4 | 43 | #include <asm/uaccess.h> |
45d607ed RA |
44 | |
45 | #include "hvc_console.h" | |
1da177e4 LT |
46 | |
47 | #define HVC_MAJOR 229 | |
48 | #define HVC_MINOR 0 | |
49 | ||
1da177e4 LT |
50 | /* |
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 | /* | |
45d607ed RA |
57 | * 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. | |
1da177e4 | 60 | */ |
1da177e4 LT |
61 | #define N_OUTBUF 16 |
62 | #define N_INBUF 16 | |
63 | ||
45d607ed | 64 | #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
1da177e4 | 65 | |
837dcfaf MM |
66 | static struct tty_driver *hvc_driver; |
67 | static struct task_struct *hvc_task; | |
68 | ||
69 | /* Picks up late kicks after list walk but before schedule() */ | |
70 | static int hvc_kicked; | |
71 | ||
3e6c6f63 RR |
72 | static int hvc_init(void); |
73 | ||
837dcfaf MM |
74 | #ifdef CONFIG_MAGIC_SYSRQ |
75 | static int sysrq_pressed; | |
76 | #endif | |
77 | ||
1da177e4 | 78 | /* dynamic list of hvc_struct instances */ |
bed9759b | 79 | static LIST_HEAD(hvc_structs); |
1da177e4 LT |
80 | |
81 | /* | |
82 | * Protect the list of hvc_struct instances from inserts and removals during | |
83 | * list traversal. | |
84 | */ | |
85 | static DEFINE_SPINLOCK(hvc_structs_lock); | |
86 | ||
837dcfaf | 87 | /* |
6f24808e MM |
88 | * 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 | |
c3ea6921 | 90 | * a console candidate registered with hvc_instantiate(). |
837dcfaf | 91 | */ |
6f24808e | 92 | static int last_hvc = -1; |
837dcfaf MM |
93 | |
94 | /* | |
c3ea6921 | 95 | * Do not call this function with either the hvc_structs_lock or the hvc_struct |
12b20ded | 96 | * lock held. If successful, this function increments the kref reference |
837dcfaf MM |
97 | * count against the target hvc_struct so it should be released when finished. |
98 | */ | |
4fa156ea | 99 | static struct hvc_struct *hvc_get_by_index(int index) |
837dcfaf MM |
100 | { |
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) { | |
12b20ded | 109 | kref_get(&hp->kref); |
837dcfaf MM |
110 | 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 | ||
122 | ||
1da177e4 LT |
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 | */ | |
b5113068 | 129 | static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
64e4da57 MM |
130 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
131 | {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; | |
1da177e4 | 132 | |
837dcfaf MM |
133 | /* |
134 | * Console APIs, NOT TTY. These APIs are available immediately when | |
135 | * hvc_console_setup() finds adapters. | |
136 | */ | |
137 | ||
4fa156ea AB |
138 | static void hvc_console_print(struct console *co, const char *b, |
139 | unsigned count) | |
837dcfaf | 140 | { |
45d607ed | 141 | char c[N_OUTBUF] __ALIGNED__; |
837dcfaf | 142 | unsigned i = 0, n = 0; |
030ffad2 | 143 | int r, donecr = 0, index = co->index; |
837dcfaf MM |
144 | |
145 | /* Console access attempt outside of acceptable console range. */ | |
030ffad2 | 146 | if (index >= MAX_NR_HVC_CONSOLES) |
837dcfaf MM |
147 | return; |
148 | ||
c3ea6921 | 149 | /* This console adapter was removed so it is not usable. */ |
ecfcbee7 | 150 | if (vtermnos[index] == -1) |
837dcfaf MM |
151 | 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 { | |
030ffad2 | 164 | r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
3feebbb5 | 165 | if (r <= 0) { |
837dcfaf MM |
166 | /* 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 | ||
177 | static struct tty_driver *hvc_console_device(struct console *c, int *index) | |
178 | { | |
7805b1b2 MM |
179 | if (vtermnos[c->index] == -1) |
180 | return NULL; | |
181 | ||
837dcfaf MM |
182 | *index = c->index; |
183 | return hvc_driver; | |
184 | } | |
185 | ||
186 | static int __init hvc_console_setup(struct console *co, char *options) | |
187 | { | |
7805b1b2 MM |
188 | if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
189 | return -ENODEV; | |
190 | ||
191 | if (vtermnos[co->index] == -1) | |
192 | return -ENODEV; | |
193 | ||
837dcfaf MM |
194 | return 0; |
195 | } | |
196 | ||
4455b119 | 197 | static struct console hvc_console = { |
837dcfaf MM |
198 | .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 | ||
d5ee257c | 206 | /* |
c3ea6921 | 207 | * Early console initialization. Precedes driver initialization. |
d5ee257c MM |
208 | * |
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 | */ | |
837dcfaf MM |
221 | static int __init hvc_console_init(void) |
222 | { | |
4455b119 | 223 | register_console(&hvc_console); |
837dcfaf MM |
224 | return 0; |
225 | } | |
226 | console_initcall(hvc_console_init); | |
1da177e4 | 227 | |
12b20ded GKH |
228 | /* callback when the kboject ref count reaches zero. */ |
229 | static 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 | ||
1da177e4 | 245 | /* |
6f24808e MM |
246 | * 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. | |
1da177e4 | 250 | */ |
b5113068 | 251 | int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) |
837dcfaf | 252 | { |
7805b1b2 MM |
253 | struct hvc_struct *hp; |
254 | ||
837dcfaf MM |
255 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
256 | return -1; | |
1da177e4 | 257 | |
837dcfaf MM |
258 | if (vtermnos[index] != -1) |
259 | return -1; | |
260 | ||
c3ea6921 | 261 | /* make sure no no tty has been registered in this index */ |
7805b1b2 MM |
262 | hp = hvc_get_by_index(index); |
263 | if (hp) { | |
12b20ded | 264 | kref_put(&hp->kref, destroy_hvc_struct); |
7805b1b2 MM |
265 | return -1; |
266 | } | |
267 | ||
837dcfaf | 268 | vtermnos[index] = vtermno; |
030ffad2 | 269 | cons_ops[index] = ops; |
6f24808e | 270 | |
c3ea6921 | 271 | /* reserve all indices up to and including this index */ |
6f24808e MM |
272 | if (last_hvc < index) |
273 | last_hvc = index; | |
274 | ||
d5ee257c MM |
275 | /* 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 | */ | |
4455b119 CM |
279 | if (index == hvc_console.index) |
280 | register_console(&hvc_console); | |
d5ee257c | 281 | |
837dcfaf MM |
282 | return 0; |
283 | } | |
7721c494 | 284 | EXPORT_SYMBOL_GPL(hvc_instantiate); |
1da177e4 LT |
285 | |
286 | /* Wake the sleeping khvcd */ | |
611e097d | 287 | void hvc_kick(void) |
1da177e4 LT |
288 | { |
289 | hvc_kicked = 1; | |
290 | wake_up_process(hvc_task); | |
291 | } | |
7721c494 | 292 | EXPORT_SYMBOL_GPL(hvc_kick); |
1da177e4 | 293 | |
1da177e4 LT |
294 | static void hvc_unthrottle(struct tty_struct *tty) |
295 | { | |
296 | hvc_kick(); | |
297 | } | |
298 | ||
1da177e4 LT |
299 | /* |
300 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
301 | * adapter to the kernel. | |
302 | */ | |
303 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
304 | { | |
305 | struct hvc_struct *hp; | |
306 | unsigned long flags; | |
1da177e4 | 307 | int rc = 0; |
1da177e4 | 308 | |
12b20ded | 309 | /* Auto increments kref reference if found. */ |
87fd7724 | 310 | if (!(hp = hvc_get_by_index(tty->index))) |
1da177e4 | 311 | return -ENODEV; |
1da177e4 LT |
312 | |
313 | spin_lock_irqsave(&hp->lock, flags); | |
314 | /* Check and then increment for fast path open. */ | |
315 | if (hp->count++ > 0) { | |
e74d098c | 316 | tty_kref_get(tty); |
1da177e4 LT |
317 | spin_unlock_irqrestore(&hp->lock, flags); |
318 | hvc_kick(); | |
319 | return 0; | |
320 | } /* else count == 0 */ | |
321 | ||
322 | tty->driver_data = hp; | |
fb5c594c | 323 | |
e74d098c | 324 | hp->tty = tty_kref_get(tty); |
611e097d | 325 | |
1da177e4 | 326 | spin_unlock_irqrestore(&hp->lock, flags); |
611e097d | 327 | |
b1b135c8 CB |
328 | if (hp->ops->notifier_add) |
329 | rc = hp->ops->notifier_add(hp, hp->data); | |
1da177e4 LT |
330 | |
331 | /* | |
611e097d | 332 | * If the notifier fails we return an error. The tty layer |
1da177e4 LT |
333 | * 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 | |
12b20ded | 335 | * tty fields and return the kref reference. |
1da177e4 LT |
336 | */ |
337 | if (rc) { | |
338 | spin_lock_irqsave(&hp->lock, flags); | |
339 | hp->tty = NULL; | |
1da177e4 | 340 | spin_unlock_irqrestore(&hp->lock, flags); |
e74d098c | 341 | tty_kref_put(tty); |
1da177e4 | 342 | tty->driver_data = NULL; |
12b20ded | 343 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
344 | 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 | ||
352 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
353 | { | |
354 | struct hvc_struct *hp; | |
1da177e4 LT |
355 | 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 | |
12b20ded | 363 | * exit cleanly because the kref reference wasn't made. |
1da177e4 LT |
364 | */ |
365 | if (!tty->driver_data) | |
366 | return; | |
367 | ||
368 | hp = tty->driver_data; | |
e74d098c | 369 | |
1da177e4 LT |
370 | spin_lock_irqsave(&hp->lock, flags); |
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 | ||
eef2622a CB |
377 | if (hp->ops->notifier_del) |
378 | hp->ops->notifier_del(hp, hp->data); | |
379 | ||
febde371 HB |
380 | /* cancel pending tty resize work */ |
381 | cancel_work_sync(&hp->tty_resize); | |
382 | ||
1da177e4 LT |
383 | /* |
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); | |
1da177e4 LT |
389 | } 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 | ||
e74d098c | 396 | tty_kref_put(tty); |
12b20ded | 397 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
398 | } |
399 | ||
400 | static void hvc_hangup(struct tty_struct *tty) | |
401 | { | |
402 | struct hvc_struct *hp = tty->driver_data; | |
403 | unsigned long flags; | |
1da177e4 | 404 | int temp_open_count; |
1da177e4 LT |
405 | |
406 | if (!hp) | |
407 | return; | |
408 | ||
febde371 HB |
409 | /* cancel pending tty resize work */ |
410 | cancel_work_sync(&hp->tty_resize); | |
411 | ||
1da177e4 LT |
412 | 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 | ||
1da177e4 LT |
424 | temp_open_count = hp->count; |
425 | hp->count = 0; | |
426 | hp->n_outbuf = 0; | |
427 | hp->tty = NULL; | |
611e097d | 428 | |
eef2622a CB |
429 | spin_unlock_irqrestore(&hp->lock, flags); |
430 | ||
fc362e2e | 431 | if (hp->ops->notifier_hangup) |
e74d098c | 432 | hp->ops->notifier_hangup(hp, hp->data); |
611e097d | 433 | |
1da177e4 LT |
434 | while(temp_open_count) { |
435 | --temp_open_count; | |
e74d098c | 436 | tty_kref_put(tty); |
12b20ded | 437 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
438 | } |
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 | */ | |
3feebbb5 | 445 | static int hvc_push(struct hvc_struct *hp) |
1da177e4 LT |
446 | { |
447 | int n; | |
448 | ||
030ffad2 | 449 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 450 | if (n <= 0) { |
45d607ed RA |
451 | if (n == 0) { |
452 | hp->do_wakeup = 1; | |
3feebbb5 | 453 | return 0; |
45d607ed | 454 | } |
1da177e4 LT |
455 | /* 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; | |
3feebbb5 HB |
464 | |
465 | return n; | |
1da177e4 LT |
466 | } |
467 | ||
45d607ed | 468 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 469 | { |
45d607ed | 470 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
471 | unsigned long flags; |
472 | int rsize, written = 0; | |
473 | ||
45d607ed RA |
474 | /* 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 | ||
1da177e4 LT |
481 | spin_lock_irqsave(&hp->lock, flags); |
482 | ||
483 | /* Push pending writes */ | |
484 | if (hp->n_outbuf > 0) | |
485 | hvc_push(hp); | |
486 | ||
4e9e95a3 | 487 | while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { |
1da177e4 LT |
488 | 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 | ||
1da177e4 LT |
499 | /* |
500 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
501 | */ |
502 | if (hp->n_outbuf) | |
503 | hvc_kick(); | |
504 | ||
505 | return written; | |
506 | } | |
507 | ||
febde371 HB |
508 | /** |
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 | */ | |
517 | static 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); | |
febde371 HB |
525 | |
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 | ||
fc6f6238 | 535 | tty_do_resize(tty, &ws); |
febde371 HB |
536 | tty_kref_put(tty); |
537 | } | |
538 | ||
1da177e4 LT |
539 | /* |
540 | * This is actually a contract between the driver and the tty layer outlining | |
c3ea6921 | 541 | * how much write room the driver can guarantee will be sent OR BUFFERED. This |
1da177e4 LT |
542 | * driver MUST honor the return value. |
543 | */ | |
544 | static 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 | ||
4e9e95a3 | 551 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
552 | } |
553 | ||
554 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
555 | { | |
556 | struct hvc_struct *hp = tty->driver_data; | |
557 | ||
558 | if (!hp) | |
23198fda | 559 | return 0; |
1da177e4 LT |
560 | return hp->n_outbuf; |
561 | } | |
562 | ||
b791072b WS |
563 | /* |
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) | |
573 | static u32 timeout = MIN_TIMEOUT; | |
574 | ||
1da177e4 LT |
575 | #define HVC_POLL_READ 0x00000001 |
576 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 | 577 | |
611e097d | 578 | int hvc_poll(struct hvc_struct *hp) |
1da177e4 LT |
579 | { |
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; | |
3feebbb5 | 585 | int written_total = 0; |
1da177e4 LT |
586 | |
587 | spin_lock_irqsave(&hp->lock, flags); | |
588 | ||
589 | /* Push pending writes */ | |
590 | if (hp->n_outbuf > 0) | |
3feebbb5 | 591 | written_total = hvc_push(hp); |
b5374461 | 592 | |
1da177e4 | 593 | /* Reschedule us if still some write pending */ |
3feebbb5 | 594 | if (hp->n_outbuf > 0) { |
1da177e4 | 595 | poll_mask |= HVC_POLL_WRITE; |
3feebbb5 HB |
596 | /* If hvc_push() was not able to write, sleep a few msecs */ |
597 | timeout = (written_total) ? 0 : MIN_TIMEOUT; | |
598 | } | |
1da177e4 LT |
599 | |
600 | /* No tty attached, just skip */ | |
e74d098c | 601 | tty = tty_kref_get(hp->tty); |
1da177e4 LT |
602 | 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 | ||
611e097d | 609 | /* If we aren't notifier driven and aren't throttled, we always |
1da177e4 LT |
610 | * request a reschedule |
611 | */ | |
611e097d | 612 | if (!hp->irq_requested) |
1da177e4 LT |
613 | poll_mask |= HVC_POLL_READ; |
614 | ||
615 | /* Read data if any */ | |
616 | for (;;) { | |
33f0f88f | 617 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
618 | |
619 | /* If flip is full, just reschedule a later read */ | |
620 | if (count == 0) { | |
621 | poll_mask |= HVC_POLL_READ; | |
622 | break; | |
623 | } | |
624 | ||
030ffad2 | 625 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
626 | 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); | |
45d607ed RA |
632 | } 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; | |
1da177e4 LT |
639 | } |
640 | break; | |
641 | } | |
642 | for (i = 0; i < n; ++i) { | |
643 | #ifdef CONFIG_MAGIC_SYSRQ | |
4455b119 | 644 | if (hp->index == hvc_console.index) { |
2b9e0bac MM |
645 | /* Handle the SysRq Hack */ |
646 | /* XXX should support a sequence */ | |
647 | if (buf[i] == '\x0f') { /* ^O */ | |
368c1e32 HB |
648 | /* if ^O is pressed again, reset |
649 | * sysrq_pressed and flip ^O char */ | |
650 | sysrq_pressed = !sysrq_pressed; | |
651 | if (sysrq_pressed) | |
652 | continue; | |
2b9e0bac | 653 | } else if (sysrq_pressed) { |
7d12e780 | 654 | handle_sysrq(buf[i], tty); |
2b9e0bac MM |
655 | sysrq_pressed = 0; |
656 | continue; | |
657 | } | |
1da177e4 LT |
658 | } |
659 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
660 | tty_insert_flip_char(tty, buf[i], 0); | |
661 | } | |
662 | ||
1da177e4 | 663 | read_total += n; |
1da177e4 LT |
664 | } |
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 | ||
b791072b WS |
674 | if (read_total) { |
675 | /* Activity is occurring, so reset the polling backoff value to | |
676 | a minimum for performance. */ | |
677 | timeout = MIN_TIMEOUT; | |
678 | ||
fb5c594c | 679 | tty_flip_buffer_push(tty); |
b791072b | 680 | } |
e74d098c AS |
681 | if (tty) |
682 | tty_kref_put(tty); | |
b791072b | 683 | |
1da177e4 LT |
684 | return poll_mask; |
685 | } | |
7721c494 | 686 | EXPORT_SYMBOL_GPL(hvc_poll); |
1da177e4 | 687 | |
febde371 | 688 | /** |
254be490 | 689 | * __hvc_resize() - Update terminal window size information. |
febde371 HB |
690 | * @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 | */ | |
254be490 | 698 | void __hvc_resize(struct hvc_struct *hp, struct winsize ws) |
febde371 | 699 | { |
7947cf0d HB |
700 | hp->ws = ws; |
701 | schedule_work(&hp->tty_resize); | |
febde371 | 702 | } |
254be490 | 703 | EXPORT_SYMBOL_GPL(__hvc_resize); |
febde371 | 704 | |
1da177e4 LT |
705 | /* |
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 | */ | |
5605d4de | 710 | static int khvcd(void *unused) |
1da177e4 LT |
711 | { |
712 | int poll_mask; | |
713 | struct hvc_struct *hp; | |
714 | ||
83144186 | 715 | set_freezable(); |
1da177e4 LT |
716 | __set_current_state(TASK_RUNNING); |
717 | do { | |
718 | poll_mask = 0; | |
719 | hvc_kicked = 0; | |
b64074e4 | 720 | try_to_freeze(); |
1da177e4 | 721 | wmb(); |
1c8950ff | 722 | if (!cpus_are_in_xmon()) { |
1da177e4 LT |
723 | spin_lock(&hvc_structs_lock); |
724 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
725 | 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; | |
1da177e4 LT |
732 | set_current_state(TASK_INTERRUPTIBLE); |
733 | if (!hvc_kicked) { | |
734 | if (poll_mask == 0) | |
735 | schedule(); | |
b791072b WS |
736 | else { |
737 | if (timeout < MAX_TIMEOUT) | |
738 | timeout += (timeout >> 6) + 1; | |
739 | ||
740 | msleep_interruptible(timeout); | |
741 | } | |
1da177e4 LT |
742 | } |
743 | __set_current_state(TASK_RUNNING); | |
744 | } while (!kthread_should_stop()); | |
745 | ||
746 | return 0; | |
747 | } | |
748 | ||
b68e31d0 | 749 | static const struct tty_operations hvc_ops = { |
1da177e4 LT |
750 | .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 | ||
119ea109 AS |
759 | struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, |
760 | const struct hv_ops *ops, | |
761 | int outbuf_size) | |
1da177e4 LT |
762 | { |
763 | struct hvc_struct *hp; | |
6f24808e | 764 | int i; |
1da177e4 | 765 | |
3e6c6f63 RR |
766 | /* 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 | ||
2da7582f | 773 | hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
4e9e95a3 | 774 | GFP_KERNEL); |
1da177e4 | 775 | if (!hp) |
acad9559 | 776 | return ERR_PTR(-ENOMEM); |
1da177e4 | 777 | |
acad9559 | 778 | hp->vtermno = vtermno; |
611e097d | 779 | hp->data = data; |
030ffad2 | 780 | hp->ops = ops; |
4e9e95a3 SR |
781 | hp->outbuf_size = outbuf_size; |
782 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 | 783 | |
12b20ded | 784 | kref_init(&hp->kref); |
1da177e4 | 785 | |
febde371 | 786 | INIT_WORK(&hp->tty_resize, hvc_set_winsz); |
1da177e4 LT |
787 | spin_lock_init(&hp->lock); |
788 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
789 | |
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++) | |
45d607ed RA |
795 | if (vtermnos[i] == hp->vtermno && |
796 | cons_ops[i] == hp->ops) | |
6f24808e MM |
797 | 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 | ||
1da177e4 LT |
805 | list_add_tail(&(hp->next), &hvc_structs); |
806 | spin_unlock(&hvc_structs_lock); | |
807 | ||
acad9559 | 808 | return hp; |
1da177e4 | 809 | } |
7721c494 | 810 | EXPORT_SYMBOL_GPL(hvc_alloc); |
1da177e4 | 811 | |
934752d8 | 812 | int hvc_remove(struct hvc_struct *hp) |
1da177e4 | 813 | { |
1da177e4 | 814 | unsigned long flags; |
1da177e4 LT |
815 | struct tty_struct *tty; |
816 | ||
817 | spin_lock_irqsave(&hp->lock, flags); | |
e74d098c | 818 | tty = tty_kref_get(hp->tty); |
1da177e4 LT |
819 | |
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 | /* | |
12b20ded GKH |
828 | * We 'put' the instance that was grabbed when the kref instance |
829 | * was initialized using kref_init(). Let the last holder of this | |
e74d098c | 830 | * kref cause it to be removed, which will probably be the tty_vhangup |
1da177e4 LT |
831 | * below. |
832 | */ | |
12b20ded | 833 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
834 | |
835 | /* | |
e74d098c | 836 | * This function call will auto chain call hvc_hangup. |
1da177e4 | 837 | */ |
e74d098c AS |
838 | if (tty) { |
839 | tty_vhangup(tty); | |
840 | tty_kref_put(tty); | |
841 | } | |
1da177e4 LT |
842 | return 0; |
843 | } | |
c0cefebc | 844 | EXPORT_SYMBOL_GPL(hvc_remove); |
1da177e4 | 845 | |
3e6c6f63 RR |
846 | /* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
847 | static int hvc_init(void) | |
1da177e4 | 848 | { |
55aab8cd | 849 | struct tty_driver *drv; |
3e6c6f63 | 850 | int err; |
55aab8cd | 851 | |
5f6d9c07 | 852 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd | 853 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
3e6c6f63 RR |
854 | if (!drv) { |
855 | err = -ENOMEM; | |
856 | goto out; | |
857 | } | |
1da177e4 | 858 | |
55aab8cd | 859 | drv->owner = THIS_MODULE; |
55aab8cd MN |
860 | 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; | |
56ce9e2b | 866 | drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; |
55aab8cd | 867 | tty_set_operations(drv, &hvc_ops); |
1da177e4 | 868 | |
1da177e4 LT |
869 | /* 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)) { | |
3e6c6f63 RR |
873 | printk(KERN_ERR "Couldn't create kthread for console.\n"); |
874 | err = PTR_ERR(hvc_task); | |
875 | goto put_tty; | |
1da177e4 LT |
876 | } |
877 | ||
3e6c6f63 RR |
878 | err = tty_register_driver(drv); |
879 | if (err) { | |
880 | printk(KERN_ERR "Couldn't register hvc console driver\n"); | |
881 | goto stop_thread; | |
882 | } | |
ef4cbee0 | 883 | |
9fef3d2d MM |
884 | /* |
885 | * Make sure tty is fully registered before allowing it to be | |
886 | * found by hvc_console_device. | |
887 | */ | |
888 | smp_mb(); | |
55aab8cd | 889 | hvc_driver = drv; |
acad9559 | 890 | return 0; |
3e6c6f63 | 891 | |
3e6c6f63 RR |
892 | stop_thread: |
893 | kthread_stop(hvc_task); | |
894 | hvc_task = NULL; | |
2571cd6a JL |
895 | put_tty: |
896 | put_tty_driver(drv); | |
3e6c6f63 RR |
897 | out: |
898 | return err; | |
1da177e4 LT |
899 | } |
900 | ||
c3ea6921 | 901 | /* This isn't particularly necessary due to this being a console driver |
320da0d2 MM |
902 | * but it is nice to be thorough. |
903 | */ | |
1da177e4 LT |
904 | static void __exit hvc_exit(void) |
905 | { | |
3e6c6f63 RR |
906 | if (hvc_driver) { |
907 | kthread_stop(hvc_task); | |
1da177e4 | 908 | |
3e6c6f63 RR |
909 | tty_unregister_driver(hvc_driver); |
910 | /* return tty_struct instances allocated in hvc_init(). */ | |
911 | put_tty_driver(hvc_driver); | |
4455b119 | 912 | unregister_console(&hvc_console); |
3e6c6f63 | 913 | } |
1da177e4 | 914 | } |
1da177e4 | 915 | module_exit(hvc_exit); |