]>
Commit | Line | Data |
---|---|---|
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> | |
30 | #include <linux/kobject.h> | |
31 | #include <linux/kthread.h> | |
32 | #include <linux/list.h> | |
33 | #include <linux/module.h> | |
34 | #include <linux/major.h> | |
35 | #include <linux/sysrq.h> | |
36 | #include <linux/tty.h> | |
37 | #include <linux/tty_flip.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/spinlock.h> | |
40 | #include <linux/delay.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 | ||
49 | #define TIMEOUT (10) | |
50 | ||
51 | /* | |
52 | * Wait this long per iteration while trying to push buffered data to the | |
53 | * hypervisor before allowing the tty to complete a close operation. | |
54 | */ | |
55 | #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ | |
56 | ||
57 | /* | |
45d607ed RA |
58 | * These sizes are most efficient for vio, because they are the |
59 | * native transfer size. We could make them selectable in the | |
60 | * future to better deal with backends that want other buffer sizes. | |
1da177e4 | 61 | */ |
1da177e4 LT |
62 | #define N_OUTBUF 16 |
63 | #define N_INBUF 16 | |
64 | ||
45d607ed | 65 | #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
1da177e4 | 66 | |
837dcfaf MM |
67 | static struct tty_driver *hvc_driver; |
68 | static struct task_struct *hvc_task; | |
69 | ||
70 | /* Picks up late kicks after list walk but before schedule() */ | |
71 | static int hvc_kicked; | |
72 | ||
73 | #ifdef CONFIG_MAGIC_SYSRQ | |
74 | static int sysrq_pressed; | |
75 | #endif | |
76 | ||
1da177e4 LT |
77 | struct hvc_struct { |
78 | spinlock_t lock; | |
79 | int index; | |
80 | struct tty_struct *tty; | |
81 | unsigned int count; | |
82 | int do_wakeup; | |
4e9e95a3 SR |
83 | char *outbuf; |
84 | int outbuf_size; | |
1da177e4 LT |
85 | int n_outbuf; |
86 | uint32_t vtermno; | |
030ffad2 | 87 | struct hv_ops *ops; |
1da177e4 LT |
88 | int irq_requested; |
89 | int irq; | |
90 | struct list_head next; | |
91 | struct kobject kobj; /* ref count & hvc_struct lifetime */ | |
1da177e4 LT |
92 | }; |
93 | ||
94 | /* dynamic list of hvc_struct instances */ | |
95 | static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs); | |
96 | ||
97 | /* | |
98 | * Protect the list of hvc_struct instances from inserts and removals during | |
99 | * list traversal. | |
100 | */ | |
101 | static DEFINE_SPINLOCK(hvc_structs_lock); | |
102 | ||
837dcfaf | 103 | /* |
6f24808e MM |
104 | * This value is used to assign a tty->index value to a hvc_struct based |
105 | * upon order of exposure via hvc_probe(), when we can not match it to | |
106 | * a console canidate registered with hvc_instantiate(). | |
837dcfaf | 107 | */ |
6f24808e | 108 | static int last_hvc = -1; |
837dcfaf MM |
109 | |
110 | /* | |
111 | * Do not call this function with either the hvc_strucst_lock or the hvc_struct | |
112 | * lock held. If successful, this function increments the kobject reference | |
113 | * count against the target hvc_struct so it should be released when finished. | |
114 | */ | |
115 | struct hvc_struct *hvc_get_by_index(int index) | |
116 | { | |
117 | struct hvc_struct *hp; | |
118 | unsigned long flags; | |
119 | ||
120 | spin_lock(&hvc_structs_lock); | |
121 | ||
122 | list_for_each_entry(hp, &hvc_structs, next) { | |
123 | spin_lock_irqsave(&hp->lock, flags); | |
124 | if (hp->index == index) { | |
125 | kobject_get(&hp->kobj); | |
126 | spin_unlock_irqrestore(&hp->lock, flags); | |
127 | spin_unlock(&hvc_structs_lock); | |
128 | return hp; | |
129 | } | |
130 | spin_unlock_irqrestore(&hp->lock, flags); | |
131 | } | |
132 | hp = NULL; | |
133 | ||
134 | spin_unlock(&hvc_structs_lock); | |
135 | return hp; | |
136 | } | |
137 | ||
138 | ||
1da177e4 LT |
139 | /* |
140 | * Initial console vtermnos for console API usage prior to full console | |
141 | * initialization. Any vty adapter outside this range will not have usable | |
142 | * console interfaces but can still be used as a tty device. This has to be | |
143 | * static because kmalloc will not work during early console init. | |
144 | */ | |
030ffad2 | 145 | static struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
64e4da57 MM |
146 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
147 | {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; | |
1da177e4 | 148 | |
837dcfaf MM |
149 | /* |
150 | * Console APIs, NOT TTY. These APIs are available immediately when | |
151 | * hvc_console_setup() finds adapters. | |
152 | */ | |
153 | ||
154 | void hvc_console_print(struct console *co, const char *b, unsigned count) | |
155 | { | |
45d607ed | 156 | char c[N_OUTBUF] __ALIGNED__; |
837dcfaf | 157 | unsigned i = 0, n = 0; |
030ffad2 | 158 | int r, donecr = 0, index = co->index; |
837dcfaf MM |
159 | |
160 | /* Console access attempt outside of acceptable console range. */ | |
030ffad2 | 161 | if (index >= MAX_NR_HVC_CONSOLES) |
837dcfaf MM |
162 | return; |
163 | ||
164 | /* This console adapter was removed so it is not useable. */ | |
030ffad2 | 165 | if (vtermnos[index] < 0) |
837dcfaf MM |
166 | return; |
167 | ||
168 | while (count > 0 || i > 0) { | |
169 | if (count > 0 && i < sizeof(c)) { | |
170 | if (b[n] == '\n' && !donecr) { | |
171 | c[i++] = '\r'; | |
172 | donecr = 1; | |
173 | } else { | |
174 | c[i++] = b[n++]; | |
175 | donecr = 0; | |
176 | --count; | |
177 | } | |
178 | } else { | |
030ffad2 | 179 | r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
837dcfaf MM |
180 | if (r < 0) { |
181 | /* throw away chars on error */ | |
182 | i = 0; | |
183 | } else if (r > 0) { | |
184 | i -= r; | |
185 | if (i > 0) | |
186 | memmove(c, c+r, i); | |
187 | } | |
188 | } | |
189 | } | |
190 | } | |
191 | ||
192 | static struct tty_driver *hvc_console_device(struct console *c, int *index) | |
193 | { | |
7805b1b2 MM |
194 | if (vtermnos[c->index] == -1) |
195 | return NULL; | |
196 | ||
837dcfaf MM |
197 | *index = c->index; |
198 | return hvc_driver; | |
199 | } | |
200 | ||
201 | static int __init hvc_console_setup(struct console *co, char *options) | |
202 | { | |
7805b1b2 MM |
203 | if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
204 | return -ENODEV; | |
205 | ||
206 | if (vtermnos[co->index] == -1) | |
207 | return -ENODEV; | |
208 | ||
837dcfaf MM |
209 | return 0; |
210 | } | |
211 | ||
212 | struct console hvc_con_driver = { | |
213 | .name = "hvc", | |
214 | .write = hvc_console_print, | |
215 | .device = hvc_console_device, | |
216 | .setup = hvc_console_setup, | |
217 | .flags = CON_PRINTBUFFER, | |
218 | .index = -1, | |
219 | }; | |
220 | ||
d5ee257c MM |
221 | /* |
222 | * Early console initialization. Preceeds driver initialization. | |
223 | * | |
224 | * (1) we are first, and the user specified another driver | |
225 | * -- index will remain -1 | |
226 | * (2) we are first and the user specified no driver | |
227 | * -- index will be set to 0, then we will fail setup. | |
228 | * (3) we are first and the user specified our driver | |
229 | * -- index will be set to user specified driver, and we will fail | |
230 | * (4) we are after driver, and this initcall will register us | |
231 | * -- if the user didn't specify a driver then the console will match | |
232 | * | |
233 | * Note that for cases 2 and 3, we will match later when the io driver | |
234 | * calls hvc_instantiate() and call register again. | |
235 | */ | |
837dcfaf MM |
236 | static int __init hvc_console_init(void) |
237 | { | |
837dcfaf MM |
238 | register_console(&hvc_con_driver); |
239 | return 0; | |
240 | } | |
241 | console_initcall(hvc_console_init); | |
1da177e4 LT |
242 | |
243 | /* | |
6f24808e MM |
244 | * hvc_instantiate() is an early console discovery method which locates |
245 | * consoles * prior to the vio subsystem discovering them. Hotplugged | |
246 | * vty adapters do NOT get an hvc_instantiate() callback since they | |
247 | * appear after early console init. | |
1da177e4 | 248 | */ |
030ffad2 | 249 | int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops) |
837dcfaf | 250 | { |
7805b1b2 MM |
251 | struct hvc_struct *hp; |
252 | ||
837dcfaf MM |
253 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
254 | return -1; | |
1da177e4 | 255 | |
837dcfaf MM |
256 | if (vtermnos[index] != -1) |
257 | return -1; | |
258 | ||
7805b1b2 MM |
259 | /* make sure no no tty has been registerd in this index */ |
260 | hp = hvc_get_by_index(index); | |
261 | if (hp) { | |
262 | kobject_put(&hp->kobj); | |
263 | return -1; | |
264 | } | |
265 | ||
837dcfaf | 266 | vtermnos[index] = vtermno; |
030ffad2 | 267 | cons_ops[index] = ops; |
6f24808e MM |
268 | |
269 | /* reserve all indices upto and including this index */ | |
270 | if (last_hvc < index) | |
271 | last_hvc = index; | |
272 | ||
d5ee257c MM |
273 | /* if this index is what the user requested, then register |
274 | * now (setup won't fail at this point). It's ok to just | |
275 | * call register again if previously .setup failed. | |
276 | */ | |
277 | if (index == hvc_con_driver.index) | |
278 | register_console(&hvc_con_driver); | |
279 | ||
837dcfaf MM |
280 | return 0; |
281 | } | |
acad9559 | 282 | EXPORT_SYMBOL(hvc_instantiate); |
1da177e4 LT |
283 | |
284 | /* Wake the sleeping khvcd */ | |
285 | static void hvc_kick(void) | |
286 | { | |
287 | hvc_kicked = 1; | |
288 | wake_up_process(hvc_task); | |
289 | } | |
290 | ||
8b67f8c1 MM |
291 | static int hvc_poll(struct hvc_struct *hp); |
292 | ||
1da177e4 LT |
293 | /* |
294 | * NOTE: This API isn't used if the console adapter doesn't support interrupts. | |
295 | * In this case the console is poll driven. | |
296 | */ | |
7d12e780 | 297 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance) |
1da177e4 | 298 | { |
8b67f8c1 MM |
299 | /* if hvc_poll request a repoll, then kick the hvcd thread */ |
300 | if (hvc_poll(dev_instance)) | |
301 | hvc_kick(); | |
1da177e4 LT |
302 | return IRQ_HANDLED; |
303 | } | |
304 | ||
305 | static void hvc_unthrottle(struct tty_struct *tty) | |
306 | { | |
307 | hvc_kick(); | |
308 | } | |
309 | ||
1da177e4 LT |
310 | /* |
311 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
312 | * adapter to the kernel. | |
313 | */ | |
314 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
315 | { | |
316 | struct hvc_struct *hp; | |
317 | unsigned long flags; | |
318 | int irq = NO_IRQ; | |
319 | int rc = 0; | |
320 | struct kobject *kobjp; | |
321 | ||
322 | /* Auto increments kobject reference if found. */ | |
87fd7724 | 323 | if (!(hp = hvc_get_by_index(tty->index))) |
1da177e4 | 324 | return -ENODEV; |
1da177e4 LT |
325 | |
326 | spin_lock_irqsave(&hp->lock, flags); | |
327 | /* Check and then increment for fast path open. */ | |
328 | if (hp->count++ > 0) { | |
329 | spin_unlock_irqrestore(&hp->lock, flags); | |
330 | hvc_kick(); | |
331 | return 0; | |
332 | } /* else count == 0 */ | |
333 | ||
334 | tty->driver_data = hp; | |
fb5c594c MO |
335 | tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */ |
336 | ||
1da177e4 LT |
337 | hp->tty = tty; |
338 | /* Save for request_irq outside of spin_lock. */ | |
339 | irq = hp->irq; | |
340 | if (irq != NO_IRQ) | |
341 | hp->irq_requested = 1; | |
342 | ||
343 | kobjp = &hp->kobj; | |
344 | ||
345 | spin_unlock_irqrestore(&hp->lock, flags); | |
346 | /* check error, fallback to non-irq */ | |
347 | if (irq != NO_IRQ) | |
0f2ed4c6 | 348 | rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED, "hvc_console", hp); |
1da177e4 LT |
349 | |
350 | /* | |
351 | * If the request_irq() fails and we return an error. The tty layer | |
352 | * will call hvc_close() after a failed open but we don't want to clean | |
353 | * up there so we'll clean up here and clear out the previously set | |
354 | * tty fields and return the kobject reference. | |
355 | */ | |
356 | if (rc) { | |
357 | spin_lock_irqsave(&hp->lock, flags); | |
358 | hp->tty = NULL; | |
359 | hp->irq_requested = 0; | |
360 | spin_unlock_irqrestore(&hp->lock, flags); | |
361 | tty->driver_data = NULL; | |
362 | kobject_put(kobjp); | |
363 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); | |
364 | } | |
365 | /* Force wakeup of the polling thread */ | |
366 | hvc_kick(); | |
367 | ||
368 | return rc; | |
369 | } | |
370 | ||
371 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
372 | { | |
373 | struct hvc_struct *hp; | |
374 | struct kobject *kobjp; | |
375 | int irq = NO_IRQ; | |
376 | unsigned long flags; | |
377 | ||
378 | if (tty_hung_up_p(filp)) | |
379 | return; | |
380 | ||
381 | /* | |
382 | * No driver_data means that this close was issued after a failed | |
383 | * hvc_open by the tty layer's release_dev() function and we can just | |
384 | * exit cleanly because the kobject reference wasn't made. | |
385 | */ | |
386 | if (!tty->driver_data) | |
387 | return; | |
388 | ||
389 | hp = tty->driver_data; | |
390 | spin_lock_irqsave(&hp->lock, flags); | |
391 | ||
392 | kobjp = &hp->kobj; | |
393 | if (--hp->count == 0) { | |
394 | if (hp->irq_requested) | |
395 | irq = hp->irq; | |
396 | hp->irq_requested = 0; | |
397 | ||
398 | /* We are done with the tty pointer now. */ | |
399 | hp->tty = NULL; | |
400 | spin_unlock_irqrestore(&hp->lock, flags); | |
401 | ||
402 | /* | |
403 | * Chain calls chars_in_buffer() and returns immediately if | |
404 | * there is no buffered data otherwise sleeps on a wait queue | |
405 | * waking periodically to check chars_in_buffer(). | |
406 | */ | |
407 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
408 | ||
409 | if (irq != NO_IRQ) | |
410 | free_irq(irq, hp); | |
411 | ||
412 | } else { | |
413 | if (hp->count < 0) | |
414 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
415 | hp->vtermno, hp->count); | |
416 | spin_unlock_irqrestore(&hp->lock, flags); | |
417 | } | |
418 | ||
419 | kobject_put(kobjp); | |
420 | } | |
421 | ||
422 | static void hvc_hangup(struct tty_struct *tty) | |
423 | { | |
424 | struct hvc_struct *hp = tty->driver_data; | |
425 | unsigned long flags; | |
426 | int irq = NO_IRQ; | |
427 | int temp_open_count; | |
428 | struct kobject *kobjp; | |
429 | ||
430 | if (!hp) | |
431 | return; | |
432 | ||
433 | spin_lock_irqsave(&hp->lock, flags); | |
434 | ||
435 | /* | |
436 | * The N_TTY line discipline has problems such that in a close vs | |
437 | * open->hangup case this can be called after the final close so prevent | |
438 | * that from happening for now. | |
439 | */ | |
440 | if (hp->count <= 0) { | |
441 | spin_unlock_irqrestore(&hp->lock, flags); | |
442 | return; | |
443 | } | |
444 | ||
445 | kobjp = &hp->kobj; | |
446 | temp_open_count = hp->count; | |
447 | hp->count = 0; | |
448 | hp->n_outbuf = 0; | |
449 | hp->tty = NULL; | |
450 | if (hp->irq_requested) | |
451 | /* Saved for use outside of spin_lock. */ | |
452 | irq = hp->irq; | |
453 | hp->irq_requested = 0; | |
454 | spin_unlock_irqrestore(&hp->lock, flags); | |
455 | if (irq != NO_IRQ) | |
456 | free_irq(irq, hp); | |
457 | while(temp_open_count) { | |
458 | --temp_open_count; | |
459 | kobject_put(kobjp); | |
460 | } | |
461 | } | |
462 | ||
463 | /* | |
464 | * Push buffered characters whether they were just recently buffered or waiting | |
465 | * on a blocked hypervisor. Call this function with hp->lock held. | |
466 | */ | |
467 | static void hvc_push(struct hvc_struct *hp) | |
468 | { | |
469 | int n; | |
470 | ||
030ffad2 | 471 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 472 | if (n <= 0) { |
45d607ed RA |
473 | if (n == 0) { |
474 | hp->do_wakeup = 1; | |
1da177e4 | 475 | return; |
45d607ed | 476 | } |
1da177e4 LT |
477 | /* throw away output on error; this happens when |
478 | there is no session connected to the vterm. */ | |
479 | hp->n_outbuf = 0; | |
480 | } else | |
481 | hp->n_outbuf -= n; | |
482 | if (hp->n_outbuf > 0) | |
483 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
484 | else | |
485 | hp->do_wakeup = 1; | |
486 | } | |
487 | ||
45d607ed | 488 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 489 | { |
45d607ed | 490 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
491 | unsigned long flags; |
492 | int rsize, written = 0; | |
493 | ||
45d607ed RA |
494 | /* This write was probably executed during a tty close. */ |
495 | if (!hp) | |
496 | return -EPIPE; | |
497 | ||
498 | if (hp->count <= 0) | |
499 | return -EIO; | |
500 | ||
1da177e4 LT |
501 | spin_lock_irqsave(&hp->lock, flags); |
502 | ||
503 | /* Push pending writes */ | |
504 | if (hp->n_outbuf > 0) | |
505 | hvc_push(hp); | |
506 | ||
4e9e95a3 | 507 | while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { |
1da177e4 LT |
508 | if (rsize > count) |
509 | rsize = count; | |
510 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
511 | count -= rsize; | |
512 | buf += rsize; | |
513 | hp->n_outbuf += rsize; | |
514 | written += rsize; | |
515 | hvc_push(hp); | |
516 | } | |
517 | spin_unlock_irqrestore(&hp->lock, flags); | |
518 | ||
1da177e4 LT |
519 | /* |
520 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
521 | */ |
522 | if (hp->n_outbuf) | |
523 | hvc_kick(); | |
524 | ||
525 | return written; | |
526 | } | |
527 | ||
528 | /* | |
529 | * This is actually a contract between the driver and the tty layer outlining | |
530 | * how much write room the driver can guarentee will be sent OR BUFFERED. This | |
531 | * driver MUST honor the return value. | |
532 | */ | |
533 | static int hvc_write_room(struct tty_struct *tty) | |
534 | { | |
535 | struct hvc_struct *hp = tty->driver_data; | |
536 | ||
537 | if (!hp) | |
538 | return -1; | |
539 | ||
4e9e95a3 | 540 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
541 | } |
542 | ||
543 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
544 | { | |
545 | struct hvc_struct *hp = tty->driver_data; | |
546 | ||
547 | if (!hp) | |
548 | return -1; | |
549 | return hp->n_outbuf; | |
550 | } | |
551 | ||
552 | #define HVC_POLL_READ 0x00000001 | |
553 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 LT |
554 | |
555 | static int hvc_poll(struct hvc_struct *hp) | |
556 | { | |
557 | struct tty_struct *tty; | |
558 | int i, n, poll_mask = 0; | |
559 | char buf[N_INBUF] __ALIGNED__; | |
560 | unsigned long flags; | |
561 | int read_total = 0; | |
562 | ||
563 | spin_lock_irqsave(&hp->lock, flags); | |
564 | ||
565 | /* Push pending writes */ | |
566 | if (hp->n_outbuf > 0) | |
567 | hvc_push(hp); | |
b5374461 | 568 | |
1da177e4 LT |
569 | /* Reschedule us if still some write pending */ |
570 | if (hp->n_outbuf > 0) | |
571 | poll_mask |= HVC_POLL_WRITE; | |
572 | ||
573 | /* No tty attached, just skip */ | |
574 | tty = hp->tty; | |
575 | if (tty == NULL) | |
576 | goto bail; | |
577 | ||
578 | /* Now check if we can get data (are we throttled ?) */ | |
579 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
580 | goto throttled; | |
581 | ||
582 | /* If we aren't interrupt driven and aren't throttled, we always | |
583 | * request a reschedule | |
584 | */ | |
585 | if (hp->irq == NO_IRQ) | |
586 | poll_mask |= HVC_POLL_READ; | |
587 | ||
588 | /* Read data if any */ | |
589 | for (;;) { | |
33f0f88f | 590 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
591 | |
592 | /* If flip is full, just reschedule a later read */ | |
593 | if (count == 0) { | |
594 | poll_mask |= HVC_POLL_READ; | |
595 | break; | |
596 | } | |
597 | ||
030ffad2 | 598 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
599 | if (n <= 0) { |
600 | /* Hangup the tty when disconnected from host */ | |
601 | if (n == -EPIPE) { | |
602 | spin_unlock_irqrestore(&hp->lock, flags); | |
603 | tty_hangup(tty); | |
604 | spin_lock_irqsave(&hp->lock, flags); | |
45d607ed RA |
605 | } else if ( n == -EAGAIN ) { |
606 | /* | |
607 | * Some back-ends can only ensure a certain min | |
608 | * num of bytes read, which may be > 'count'. | |
609 | * Let the tty clear the flip buff to make room. | |
610 | */ | |
611 | poll_mask |= HVC_POLL_READ; | |
1da177e4 LT |
612 | } |
613 | break; | |
614 | } | |
615 | for (i = 0; i < n; ++i) { | |
616 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
617 | if (hp->index == hvc_con_driver.index) { |
618 | /* Handle the SysRq Hack */ | |
619 | /* XXX should support a sequence */ | |
620 | if (buf[i] == '\x0f') { /* ^O */ | |
621 | sysrq_pressed = 1; | |
622 | continue; | |
623 | } else if (sysrq_pressed) { | |
7d12e780 | 624 | handle_sysrq(buf[i], tty); |
2b9e0bac MM |
625 | sysrq_pressed = 0; |
626 | continue; | |
627 | } | |
1da177e4 LT |
628 | } |
629 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
630 | tty_insert_flip_char(tty, buf[i], 0); | |
631 | } | |
632 | ||
1da177e4 | 633 | read_total += n; |
1da177e4 LT |
634 | } |
635 | throttled: | |
636 | /* Wakeup write queue if necessary */ | |
637 | if (hp->do_wakeup) { | |
638 | hp->do_wakeup = 0; | |
639 | tty_wakeup(tty); | |
640 | } | |
641 | bail: | |
642 | spin_unlock_irqrestore(&hp->lock, flags); | |
643 | ||
fb5c594c MO |
644 | if (read_total) |
645 | tty_flip_buffer_push(tty); | |
646 | ||
1da177e4 LT |
647 | return poll_mask; |
648 | } | |
649 | ||
650 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
651 | extern cpumask_t cpus_in_xmon; | |
652 | #else | |
653 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
654 | #endif | |
655 | ||
656 | /* | |
657 | * This kthread is either polling or interrupt driven. This is determined by | |
658 | * calling hvc_poll() who determines whether a console adapter support | |
659 | * interrupts. | |
660 | */ | |
661 | int khvcd(void *unused) | |
662 | { | |
663 | int poll_mask; | |
664 | struct hvc_struct *hp; | |
665 | ||
666 | __set_current_state(TASK_RUNNING); | |
667 | do { | |
668 | poll_mask = 0; | |
669 | hvc_kicked = 0; | |
b64074e4 | 670 | try_to_freeze(); |
1da177e4 LT |
671 | wmb(); |
672 | if (cpus_empty(cpus_in_xmon)) { | |
673 | spin_lock(&hvc_structs_lock); | |
674 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
675 | poll_mask |= hvc_poll(hp); |
676 | } | |
677 | spin_unlock(&hvc_structs_lock); | |
678 | } else | |
679 | poll_mask |= HVC_POLL_READ; | |
680 | if (hvc_kicked) | |
681 | continue; | |
b5374461 | 682 | if (poll_mask & HVC_POLL_WRITE) { |
1da177e4 LT |
683 | yield(); |
684 | continue; | |
685 | } | |
686 | set_current_state(TASK_INTERRUPTIBLE); | |
687 | if (!hvc_kicked) { | |
688 | if (poll_mask == 0) | |
689 | schedule(); | |
690 | else | |
691 | msleep_interruptible(TIMEOUT); | |
692 | } | |
693 | __set_current_state(TASK_RUNNING); | |
694 | } while (!kthread_should_stop()); | |
695 | ||
696 | return 0; | |
697 | } | |
698 | ||
b68e31d0 | 699 | static const struct tty_operations hvc_ops = { |
1da177e4 LT |
700 | .open = hvc_open, |
701 | .close = hvc_close, | |
702 | .write = hvc_write, | |
703 | .hangup = hvc_hangup, | |
704 | .unthrottle = hvc_unthrottle, | |
705 | .write_room = hvc_write_room, | |
706 | .chars_in_buffer = hvc_chars_in_buffer, | |
707 | }; | |
708 | ||
1da177e4 LT |
709 | /* callback when the kboject ref count reaches zero. */ |
710 | static void destroy_hvc_struct(struct kobject *kobj) | |
711 | { | |
712 | struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); | |
713 | unsigned long flags; | |
714 | ||
715 | spin_lock(&hvc_structs_lock); | |
716 | ||
717 | spin_lock_irqsave(&hp->lock, flags); | |
718 | list_del(&(hp->next)); | |
719 | spin_unlock_irqrestore(&hp->lock, flags); | |
720 | ||
721 | spin_unlock(&hvc_structs_lock); | |
722 | ||
723 | kfree(hp); | |
724 | } | |
725 | ||
726 | static struct kobj_type hvc_kobj_type = { | |
727 | .release = destroy_hvc_struct, | |
728 | }; | |
729 | ||
030ffad2 | 730 | struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, |
4e9e95a3 | 731 | struct hv_ops *ops, int outbuf_size) |
1da177e4 LT |
732 | { |
733 | struct hvc_struct *hp; | |
6f24808e | 734 | int i; |
1da177e4 | 735 | |
4e9e95a3 SR |
736 | hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
737 | GFP_KERNEL); | |
1da177e4 | 738 | if (!hp) |
acad9559 | 739 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
740 | |
741 | memset(hp, 0x00, sizeof(*hp)); | |
acad9559 MM |
742 | |
743 | hp->vtermno = vtermno; | |
744 | hp->irq = irq; | |
030ffad2 | 745 | hp->ops = ops; |
4e9e95a3 SR |
746 | hp->outbuf_size = outbuf_size; |
747 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 LT |
748 | |
749 | kobject_init(&hp->kobj); | |
750 | hp->kobj.ktype = &hvc_kobj_type; | |
751 | ||
752 | spin_lock_init(&hp->lock); | |
753 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
754 | |
755 | /* | |
756 | * find index to use: | |
757 | * see if this vterm id matches one registered for console. | |
758 | */ | |
759 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
45d607ed RA |
760 | if (vtermnos[i] == hp->vtermno && |
761 | cons_ops[i] == hp->ops) | |
6f24808e MM |
762 | break; |
763 | ||
764 | /* no matching slot, just use a counter */ | |
765 | if (i >= MAX_NR_HVC_CONSOLES) | |
766 | i = ++last_hvc; | |
767 | ||
768 | hp->index = i; | |
769 | ||
1da177e4 LT |
770 | list_add_tail(&(hp->next), &hvc_structs); |
771 | spin_unlock(&hvc_structs_lock); | |
772 | ||
acad9559 | 773 | return hp; |
1da177e4 | 774 | } |
acad9559 | 775 | EXPORT_SYMBOL(hvc_alloc); |
1da177e4 | 776 | |
acad9559 | 777 | int __devexit hvc_remove(struct hvc_struct *hp) |
1da177e4 | 778 | { |
1da177e4 LT |
779 | unsigned long flags; |
780 | struct kobject *kobjp; | |
781 | struct tty_struct *tty; | |
782 | ||
783 | spin_lock_irqsave(&hp->lock, flags); | |
784 | tty = hp->tty; | |
785 | kobjp = &hp->kobj; | |
786 | ||
787 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
788 | vtermnos[hp->index] = -1; | |
789 | ||
790 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
791 | ||
792 | spin_unlock_irqrestore(&hp->lock, flags); | |
793 | ||
794 | /* | |
795 | * We 'put' the instance that was grabbed when the kobject instance | |
796 | * was intialized using kobject_init(). Let the last holder of this | |
797 | * kobject cause it to be removed, which will probably be the tty_hangup | |
798 | * below. | |
799 | */ | |
800 | kobject_put(kobjp); | |
801 | ||
802 | /* | |
803 | * This function call will auto chain call hvc_hangup. The tty should | |
804 | * always be valid at this time unless a simultaneous tty close already | |
805 | * cleaned up the hvc_struct. | |
806 | */ | |
807 | if (tty) | |
808 | tty_hangup(tty); | |
809 | return 0; | |
810 | } | |
acad9559 | 811 | EXPORT_SYMBOL(hvc_remove); |
1da177e4 LT |
812 | |
813 | /* Driver initialization. Follow console initialization. This is where the TTY | |
814 | * interfaces start to become available. */ | |
815 | int __init hvc_init(void) | |
816 | { | |
55aab8cd MN |
817 | struct tty_driver *drv; |
818 | ||
5f6d9c07 | 819 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd MN |
820 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
821 | if (!drv) | |
1da177e4 LT |
822 | return -ENOMEM; |
823 | ||
55aab8cd | 824 | drv->owner = THIS_MODULE; |
55aab8cd MN |
825 | drv->driver_name = "hvc"; |
826 | drv->name = "hvc"; | |
827 | drv->major = HVC_MAJOR; | |
828 | drv->minor_start = HVC_MINOR; | |
829 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
830 | drv->init_termios = tty_std_termios; | |
831 | drv->flags = TTY_DRIVER_REAL_RAW; | |
832 | tty_set_operations(drv, &hvc_ops); | |
1da177e4 | 833 | |
1da177e4 LT |
834 | /* Always start the kthread because there can be hotplug vty adapters |
835 | * added later. */ | |
836 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
837 | if (IS_ERR(hvc_task)) { | |
838 | panic("Couldn't create kthread for console.\n"); | |
55aab8cd | 839 | put_tty_driver(drv); |
1da177e4 LT |
840 | return -EIO; |
841 | } | |
842 | ||
55aab8cd | 843 | if (tty_register_driver(drv)) |
ef4cbee0 AB |
844 | panic("Couldn't register hvc console driver\n"); |
845 | ||
55aab8cd MN |
846 | mb(); |
847 | hvc_driver = drv; | |
acad9559 | 848 | return 0; |
1da177e4 | 849 | } |
837dcfaf | 850 | module_init(hvc_init); |
1da177e4 | 851 | |
320da0d2 MM |
852 | /* This isn't particularily necessary due to this being a console driver |
853 | * but it is nice to be thorough. | |
854 | */ | |
1da177e4 LT |
855 | static void __exit hvc_exit(void) |
856 | { | |
857 | kthread_stop(hvc_task); | |
858 | ||
1da177e4 LT |
859 | tty_unregister_driver(hvc_driver); |
860 | /* return tty_struct instances allocated in hvc_init(). */ | |
861 | put_tty_driver(hvc_driver); | |
320da0d2 | 862 | unregister_console(&hvc_con_driver); |
1da177e4 | 863 | } |
1da177e4 | 864 | module_exit(hvc_exit); |