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 | */ | |
030ffad2 | 128 | static 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. */ |
030ffad2 | 149 | if (vtermnos[index] < 0) |
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 | */ |
030ffad2 | 250 | int hvc_instantiate(uint32_t vtermno, int index, 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) { | |
315 | spin_unlock_irqrestore(&hp->lock, flags); | |
316 | hvc_kick(); | |
317 | return 0; | |
318 | } /* else count == 0 */ | |
319 | ||
320 | tty->driver_data = hp; | |
fb5c594c MO |
321 | tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */ |
322 | ||
1da177e4 | 323 | hp->tty = 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 LT |
339 | spin_unlock_irqrestore(&hp->lock, flags); |
340 | tty->driver_data = NULL; | |
12b20ded | 341 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
342 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); |
343 | } | |
344 | /* Force wakeup of the polling thread */ | |
345 | hvc_kick(); | |
346 | ||
347 | return rc; | |
348 | } | |
349 | ||
350 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
351 | { | |
352 | struct hvc_struct *hp; | |
1da177e4 LT |
353 | unsigned long flags; |
354 | ||
355 | if (tty_hung_up_p(filp)) | |
356 | return; | |
357 | ||
358 | /* | |
359 | * No driver_data means that this close was issued after a failed | |
360 | * hvc_open by the tty layer's release_dev() function and we can just | |
12b20ded | 361 | * exit cleanly because the kref reference wasn't made. |
1da177e4 LT |
362 | */ |
363 | if (!tty->driver_data) | |
364 | return; | |
365 | ||
366 | hp = tty->driver_data; | |
367 | spin_lock_irqsave(&hp->lock, flags); | |
368 | ||
1da177e4 | 369 | if (--hp->count == 0) { |
1da177e4 LT |
370 | /* We are done with the tty pointer now. */ |
371 | hp->tty = NULL; | |
372 | spin_unlock_irqrestore(&hp->lock, flags); | |
373 | ||
eef2622a CB |
374 | if (hp->ops->notifier_del) |
375 | hp->ops->notifier_del(hp, hp->data); | |
376 | ||
1da177e4 LT |
377 | /* |
378 | * Chain calls chars_in_buffer() and returns immediately if | |
379 | * there is no buffered data otherwise sleeps on a wait queue | |
380 | * waking periodically to check chars_in_buffer(). | |
381 | */ | |
382 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
1da177e4 LT |
383 | } else { |
384 | if (hp->count < 0) | |
385 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
386 | hp->vtermno, hp->count); | |
387 | spin_unlock_irqrestore(&hp->lock, flags); | |
388 | } | |
389 | ||
12b20ded | 390 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
391 | } |
392 | ||
393 | static void hvc_hangup(struct tty_struct *tty) | |
394 | { | |
395 | struct hvc_struct *hp = tty->driver_data; | |
396 | unsigned long flags; | |
1da177e4 | 397 | int temp_open_count; |
1da177e4 LT |
398 | |
399 | if (!hp) | |
400 | return; | |
401 | ||
402 | spin_lock_irqsave(&hp->lock, flags); | |
403 | ||
404 | /* | |
405 | * The N_TTY line discipline has problems such that in a close vs | |
406 | * open->hangup case this can be called after the final close so prevent | |
407 | * that from happening for now. | |
408 | */ | |
409 | if (hp->count <= 0) { | |
410 | spin_unlock_irqrestore(&hp->lock, flags); | |
411 | return; | |
412 | } | |
413 | ||
1da177e4 LT |
414 | temp_open_count = hp->count; |
415 | hp->count = 0; | |
416 | hp->n_outbuf = 0; | |
417 | hp->tty = NULL; | |
611e097d | 418 | |
eef2622a CB |
419 | spin_unlock_irqrestore(&hp->lock, flags); |
420 | ||
fc362e2e HB |
421 | if (hp->ops->notifier_hangup) |
422 | hp->ops->notifier_hangup(hp, hp->data); | |
611e097d | 423 | |
1da177e4 LT |
424 | while(temp_open_count) { |
425 | --temp_open_count; | |
12b20ded | 426 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
427 | } |
428 | } | |
429 | ||
430 | /* | |
431 | * Push buffered characters whether they were just recently buffered or waiting | |
432 | * on a blocked hypervisor. Call this function with hp->lock held. | |
433 | */ | |
3feebbb5 | 434 | static int hvc_push(struct hvc_struct *hp) |
1da177e4 LT |
435 | { |
436 | int n; | |
437 | ||
030ffad2 | 438 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 439 | if (n <= 0) { |
45d607ed RA |
440 | if (n == 0) { |
441 | hp->do_wakeup = 1; | |
3feebbb5 | 442 | return 0; |
45d607ed | 443 | } |
1da177e4 LT |
444 | /* throw away output on error; this happens when |
445 | there is no session connected to the vterm. */ | |
446 | hp->n_outbuf = 0; | |
447 | } else | |
448 | hp->n_outbuf -= n; | |
449 | if (hp->n_outbuf > 0) | |
450 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
451 | else | |
452 | hp->do_wakeup = 1; | |
3feebbb5 HB |
453 | |
454 | return n; | |
1da177e4 LT |
455 | } |
456 | ||
45d607ed | 457 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 458 | { |
45d607ed | 459 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
460 | unsigned long flags; |
461 | int rsize, written = 0; | |
462 | ||
45d607ed RA |
463 | /* This write was probably executed during a tty close. */ |
464 | if (!hp) | |
465 | return -EPIPE; | |
466 | ||
467 | if (hp->count <= 0) | |
468 | return -EIO; | |
469 | ||
1da177e4 LT |
470 | spin_lock_irqsave(&hp->lock, flags); |
471 | ||
472 | /* Push pending writes */ | |
473 | if (hp->n_outbuf > 0) | |
474 | hvc_push(hp); | |
475 | ||
4e9e95a3 | 476 | while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { |
1da177e4 LT |
477 | if (rsize > count) |
478 | rsize = count; | |
479 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
480 | count -= rsize; | |
481 | buf += rsize; | |
482 | hp->n_outbuf += rsize; | |
483 | written += rsize; | |
484 | hvc_push(hp); | |
485 | } | |
486 | spin_unlock_irqrestore(&hp->lock, flags); | |
487 | ||
1da177e4 LT |
488 | /* |
489 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
490 | */ |
491 | if (hp->n_outbuf) | |
492 | hvc_kick(); | |
493 | ||
494 | return written; | |
495 | } | |
496 | ||
497 | /* | |
498 | * This is actually a contract between the driver and the tty layer outlining | |
c3ea6921 | 499 | * how much write room the driver can guarantee will be sent OR BUFFERED. This |
1da177e4 LT |
500 | * driver MUST honor the return value. |
501 | */ | |
502 | static int hvc_write_room(struct tty_struct *tty) | |
503 | { | |
504 | struct hvc_struct *hp = tty->driver_data; | |
505 | ||
506 | if (!hp) | |
507 | return -1; | |
508 | ||
4e9e95a3 | 509 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
510 | } |
511 | ||
512 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
513 | { | |
514 | struct hvc_struct *hp = tty->driver_data; | |
515 | ||
516 | if (!hp) | |
517 | return -1; | |
518 | return hp->n_outbuf; | |
519 | } | |
520 | ||
b791072b WS |
521 | /* |
522 | * timeout will vary between the MIN and MAX values defined here. By default | |
523 | * and during console activity we will use a default MIN_TIMEOUT of 10. When | |
524 | * the console is idle, we increase the timeout value on each pass through | |
525 | * msleep until we reach the max. This may be noticeable as a brief (average | |
526 | * one second) delay on the console before the console responds to input when | |
527 | * there has been no input for some time. | |
528 | */ | |
529 | #define MIN_TIMEOUT (10) | |
530 | #define MAX_TIMEOUT (2000) | |
531 | static u32 timeout = MIN_TIMEOUT; | |
532 | ||
1da177e4 LT |
533 | #define HVC_POLL_READ 0x00000001 |
534 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 | 535 | |
611e097d | 536 | int hvc_poll(struct hvc_struct *hp) |
1da177e4 LT |
537 | { |
538 | struct tty_struct *tty; | |
539 | int i, n, poll_mask = 0; | |
540 | char buf[N_INBUF] __ALIGNED__; | |
541 | unsigned long flags; | |
542 | int read_total = 0; | |
3feebbb5 | 543 | int written_total = 0; |
1da177e4 LT |
544 | |
545 | spin_lock_irqsave(&hp->lock, flags); | |
546 | ||
547 | /* Push pending writes */ | |
548 | if (hp->n_outbuf > 0) | |
3feebbb5 | 549 | written_total = hvc_push(hp); |
b5374461 | 550 | |
1da177e4 | 551 | /* Reschedule us if still some write pending */ |
3feebbb5 | 552 | if (hp->n_outbuf > 0) { |
1da177e4 | 553 | poll_mask |= HVC_POLL_WRITE; |
3feebbb5 HB |
554 | /* If hvc_push() was not able to write, sleep a few msecs */ |
555 | timeout = (written_total) ? 0 : MIN_TIMEOUT; | |
556 | } | |
1da177e4 LT |
557 | |
558 | /* No tty attached, just skip */ | |
559 | tty = hp->tty; | |
560 | if (tty == NULL) | |
561 | goto bail; | |
562 | ||
563 | /* Now check if we can get data (are we throttled ?) */ | |
564 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
565 | goto throttled; | |
566 | ||
611e097d | 567 | /* If we aren't notifier driven and aren't throttled, we always |
1da177e4 LT |
568 | * request a reschedule |
569 | */ | |
611e097d | 570 | if (!hp->irq_requested) |
1da177e4 LT |
571 | poll_mask |= HVC_POLL_READ; |
572 | ||
573 | /* Read data if any */ | |
574 | for (;;) { | |
33f0f88f | 575 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
576 | |
577 | /* If flip is full, just reschedule a later read */ | |
578 | if (count == 0) { | |
579 | poll_mask |= HVC_POLL_READ; | |
580 | break; | |
581 | } | |
582 | ||
030ffad2 | 583 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
584 | if (n <= 0) { |
585 | /* Hangup the tty when disconnected from host */ | |
586 | if (n == -EPIPE) { | |
587 | spin_unlock_irqrestore(&hp->lock, flags); | |
588 | tty_hangup(tty); | |
589 | spin_lock_irqsave(&hp->lock, flags); | |
45d607ed RA |
590 | } else if ( n == -EAGAIN ) { |
591 | /* | |
592 | * Some back-ends can only ensure a certain min | |
593 | * num of bytes read, which may be > 'count'. | |
594 | * Let the tty clear the flip buff to make room. | |
595 | */ | |
596 | poll_mask |= HVC_POLL_READ; | |
1da177e4 LT |
597 | } |
598 | break; | |
599 | } | |
600 | for (i = 0; i < n; ++i) { | |
601 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
602 | if (hp->index == hvc_con_driver.index) { |
603 | /* Handle the SysRq Hack */ | |
604 | /* XXX should support a sequence */ | |
605 | if (buf[i] == '\x0f') { /* ^O */ | |
606 | sysrq_pressed = 1; | |
607 | continue; | |
608 | } else if (sysrq_pressed) { | |
7d12e780 | 609 | handle_sysrq(buf[i], tty); |
2b9e0bac MM |
610 | sysrq_pressed = 0; |
611 | continue; | |
612 | } | |
1da177e4 LT |
613 | } |
614 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
615 | tty_insert_flip_char(tty, buf[i], 0); | |
616 | } | |
617 | ||
1da177e4 | 618 | read_total += n; |
1da177e4 LT |
619 | } |
620 | throttled: | |
621 | /* Wakeup write queue if necessary */ | |
622 | if (hp->do_wakeup) { | |
623 | hp->do_wakeup = 0; | |
624 | tty_wakeup(tty); | |
625 | } | |
626 | bail: | |
627 | spin_unlock_irqrestore(&hp->lock, flags); | |
628 | ||
b791072b WS |
629 | if (read_total) { |
630 | /* Activity is occurring, so reset the polling backoff value to | |
631 | a minimum for performance. */ | |
632 | timeout = MIN_TIMEOUT; | |
633 | ||
fb5c594c | 634 | tty_flip_buffer_push(tty); |
b791072b WS |
635 | } |
636 | ||
1da177e4 LT |
637 | return poll_mask; |
638 | } | |
7721c494 | 639 | EXPORT_SYMBOL_GPL(hvc_poll); |
1da177e4 | 640 | |
1da177e4 LT |
641 | /* |
642 | * This kthread is either polling or interrupt driven. This is determined by | |
643 | * calling hvc_poll() who determines whether a console adapter support | |
644 | * interrupts. | |
645 | */ | |
5605d4de | 646 | static int khvcd(void *unused) |
1da177e4 LT |
647 | { |
648 | int poll_mask; | |
649 | struct hvc_struct *hp; | |
650 | ||
83144186 | 651 | set_freezable(); |
1da177e4 LT |
652 | __set_current_state(TASK_RUNNING); |
653 | do { | |
654 | poll_mask = 0; | |
655 | hvc_kicked = 0; | |
b64074e4 | 656 | try_to_freeze(); |
1da177e4 | 657 | wmb(); |
1c8950ff | 658 | if (!cpus_are_in_xmon()) { |
1da177e4 LT |
659 | spin_lock(&hvc_structs_lock); |
660 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
661 | poll_mask |= hvc_poll(hp); |
662 | } | |
663 | spin_unlock(&hvc_structs_lock); | |
664 | } else | |
665 | poll_mask |= HVC_POLL_READ; | |
666 | if (hvc_kicked) | |
667 | continue; | |
1da177e4 LT |
668 | set_current_state(TASK_INTERRUPTIBLE); |
669 | if (!hvc_kicked) { | |
670 | if (poll_mask == 0) | |
671 | schedule(); | |
b791072b WS |
672 | else { |
673 | if (timeout < MAX_TIMEOUT) | |
674 | timeout += (timeout >> 6) + 1; | |
675 | ||
676 | msleep_interruptible(timeout); | |
677 | } | |
1da177e4 LT |
678 | } |
679 | __set_current_state(TASK_RUNNING); | |
680 | } while (!kthread_should_stop()); | |
681 | ||
682 | return 0; | |
683 | } | |
684 | ||
b68e31d0 | 685 | static const struct tty_operations hvc_ops = { |
1da177e4 LT |
686 | .open = hvc_open, |
687 | .close = hvc_close, | |
688 | .write = hvc_write, | |
689 | .hangup = hvc_hangup, | |
690 | .unthrottle = hvc_unthrottle, | |
691 | .write_room = hvc_write_room, | |
692 | .chars_in_buffer = hvc_chars_in_buffer, | |
693 | }; | |
694 | ||
611e097d | 695 | struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int data, |
4e9e95a3 | 696 | struct hv_ops *ops, int outbuf_size) |
1da177e4 LT |
697 | { |
698 | struct hvc_struct *hp; | |
6f24808e | 699 | int i; |
1da177e4 | 700 | |
3e6c6f63 RR |
701 | /* We wait until a driver actually comes along */ |
702 | if (!hvc_driver) { | |
703 | int err = hvc_init(); | |
704 | if (err) | |
705 | return ERR_PTR(err); | |
706 | } | |
707 | ||
4e9e95a3 SR |
708 | hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
709 | GFP_KERNEL); | |
1da177e4 | 710 | if (!hp) |
acad9559 | 711 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
712 | |
713 | memset(hp, 0x00, sizeof(*hp)); | |
acad9559 MM |
714 | |
715 | hp->vtermno = vtermno; | |
611e097d | 716 | hp->data = data; |
030ffad2 | 717 | hp->ops = ops; |
4e9e95a3 SR |
718 | hp->outbuf_size = outbuf_size; |
719 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 | 720 | |
12b20ded | 721 | kref_init(&hp->kref); |
1da177e4 LT |
722 | |
723 | spin_lock_init(&hp->lock); | |
724 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
725 | |
726 | /* | |
727 | * find index to use: | |
728 | * see if this vterm id matches one registered for console. | |
729 | */ | |
730 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
45d607ed RA |
731 | if (vtermnos[i] == hp->vtermno && |
732 | cons_ops[i] == hp->ops) | |
6f24808e MM |
733 | break; |
734 | ||
735 | /* no matching slot, just use a counter */ | |
736 | if (i >= MAX_NR_HVC_CONSOLES) | |
737 | i = ++last_hvc; | |
738 | ||
739 | hp->index = i; | |
740 | ||
1da177e4 LT |
741 | list_add_tail(&(hp->next), &hvc_structs); |
742 | spin_unlock(&hvc_structs_lock); | |
743 | ||
acad9559 | 744 | return hp; |
1da177e4 | 745 | } |
7721c494 | 746 | EXPORT_SYMBOL_GPL(hvc_alloc); |
1da177e4 | 747 | |
acad9559 | 748 | int __devexit hvc_remove(struct hvc_struct *hp) |
1da177e4 | 749 | { |
1da177e4 | 750 | unsigned long flags; |
1da177e4 LT |
751 | struct tty_struct *tty; |
752 | ||
753 | spin_lock_irqsave(&hp->lock, flags); | |
754 | tty = hp->tty; | |
1da177e4 LT |
755 | |
756 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
757 | vtermnos[hp->index] = -1; | |
758 | ||
759 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
760 | ||
761 | spin_unlock_irqrestore(&hp->lock, flags); | |
762 | ||
763 | /* | |
12b20ded GKH |
764 | * We 'put' the instance that was grabbed when the kref instance |
765 | * was initialized using kref_init(). Let the last holder of this | |
766 | * kref cause it to be removed, which will probably be the tty_hangup | |
1da177e4 LT |
767 | * below. |
768 | */ | |
12b20ded | 769 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
770 | |
771 | /* | |
772 | * This function call will auto chain call hvc_hangup. The tty should | |
773 | * always be valid at this time unless a simultaneous tty close already | |
774 | * cleaned up the hvc_struct. | |
775 | */ | |
776 | if (tty) | |
777 | tty_hangup(tty); | |
778 | return 0; | |
779 | } | |
1da177e4 | 780 | |
3e6c6f63 RR |
781 | /* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
782 | static int hvc_init(void) | |
1da177e4 | 783 | { |
55aab8cd | 784 | struct tty_driver *drv; |
3e6c6f63 | 785 | int err; |
55aab8cd | 786 | |
5f6d9c07 | 787 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd | 788 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
3e6c6f63 RR |
789 | if (!drv) { |
790 | err = -ENOMEM; | |
791 | goto out; | |
792 | } | |
1da177e4 | 793 | |
55aab8cd | 794 | drv->owner = THIS_MODULE; |
55aab8cd MN |
795 | drv->driver_name = "hvc"; |
796 | drv->name = "hvc"; | |
797 | drv->major = HVC_MAJOR; | |
798 | drv->minor_start = HVC_MINOR; | |
799 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
800 | drv->init_termios = tty_std_termios; | |
56ce9e2b | 801 | drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; |
55aab8cd | 802 | tty_set_operations(drv, &hvc_ops); |
1da177e4 | 803 | |
1da177e4 LT |
804 | /* Always start the kthread because there can be hotplug vty adapters |
805 | * added later. */ | |
806 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
807 | if (IS_ERR(hvc_task)) { | |
3e6c6f63 RR |
808 | printk(KERN_ERR "Couldn't create kthread for console.\n"); |
809 | err = PTR_ERR(hvc_task); | |
810 | goto put_tty; | |
1da177e4 LT |
811 | } |
812 | ||
3e6c6f63 RR |
813 | err = tty_register_driver(drv); |
814 | if (err) { | |
815 | printk(KERN_ERR "Couldn't register hvc console driver\n"); | |
816 | goto stop_thread; | |
817 | } | |
ef4cbee0 | 818 | |
3e6c6f63 | 819 | /* FIXME: This mb() seems completely random. Remove it. */ |
55aab8cd MN |
820 | mb(); |
821 | hvc_driver = drv; | |
acad9559 | 822 | return 0; |
3e6c6f63 | 823 | |
3e6c6f63 RR |
824 | stop_thread: |
825 | kthread_stop(hvc_task); | |
826 | hvc_task = NULL; | |
2571cd6a JL |
827 | put_tty: |
828 | put_tty_driver(drv); | |
3e6c6f63 RR |
829 | out: |
830 | return err; | |
1da177e4 LT |
831 | } |
832 | ||
c3ea6921 | 833 | /* This isn't particularly necessary due to this being a console driver |
320da0d2 MM |
834 | * but it is nice to be thorough. |
835 | */ | |
1da177e4 LT |
836 | static void __exit hvc_exit(void) |
837 | { | |
3e6c6f63 RR |
838 | if (hvc_driver) { |
839 | kthread_stop(hvc_task); | |
1da177e4 | 840 | |
3e6c6f63 RR |
841 | tty_unregister_driver(hvc_driver); |
842 | /* return tty_struct instances allocated in hvc_init(). */ | |
843 | put_tty_driver(hvc_driver); | |
844 | unregister_console(&hvc_con_driver); | |
845 | } | |
1da177e4 | 846 | } |
1da177e4 | 847 | module_exit(hvc_exit); |