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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 | ||
e51d8c90 | 25 | #include <linux/config.h> |
1da177e4 LT |
26 | #include <linux/console.h> |
27 | #include <linux/cpumask.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/kbd_kern.h> | |
30 | #include <linux/kernel.h> | |
31 | #include <linux/kobject.h> | |
32 | #include <linux/kthread.h> | |
33 | #include <linux/list.h> | |
34 | #include <linux/module.h> | |
35 | #include <linux/major.h> | |
36 | #include <linux/sysrq.h> | |
37 | #include <linux/tty.h> | |
38 | #include <linux/tty_flip.h> | |
39 | #include <linux/sched.h> | |
40 | #include <linux/spinlock.h> | |
41 | #include <linux/delay.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 | ||
50 | #define TIMEOUT (10) | |
51 | ||
52 | /* | |
53 | * Wait this long per iteration while trying to push buffered data to the | |
54 | * hypervisor before allowing the tty to complete a close operation. | |
55 | */ | |
56 | #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ | |
57 | ||
58 | /* | |
45d607ed RA |
59 | * These sizes are most efficient for vio, because they are the |
60 | * native transfer size. We could make them selectable in the | |
61 | * future to better deal with backends that want other buffer sizes. | |
1da177e4 | 62 | */ |
1da177e4 LT |
63 | #define N_OUTBUF 16 |
64 | #define N_INBUF 16 | |
65 | ||
45d607ed | 66 | #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
1da177e4 | 67 | |
837dcfaf MM |
68 | static struct tty_driver *hvc_driver; |
69 | static struct task_struct *hvc_task; | |
70 | ||
71 | /* Picks up late kicks after list walk but before schedule() */ | |
72 | static int hvc_kicked; | |
73 | ||
74 | #ifdef CONFIG_MAGIC_SYSRQ | |
75 | static int sysrq_pressed; | |
76 | #endif | |
77 | ||
1da177e4 LT |
78 | struct hvc_struct { |
79 | spinlock_t lock; | |
80 | int index; | |
81 | struct tty_struct *tty; | |
82 | unsigned int count; | |
83 | int do_wakeup; | |
84 | char outbuf[N_OUTBUF] __ALIGNED__; | |
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 | */ | |
297 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs) | |
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. */ | |
323 | if (!(hp = hvc_get_by_index(tty->index))) { | |
324 | printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n"); | |
325 | return -ENODEV; | |
326 | } | |
327 | ||
328 | spin_lock_irqsave(&hp->lock, flags); | |
329 | /* Check and then increment for fast path open. */ | |
330 | if (hp->count++ > 0) { | |
331 | spin_unlock_irqrestore(&hp->lock, flags); | |
332 | hvc_kick(); | |
333 | return 0; | |
334 | } /* else count == 0 */ | |
335 | ||
336 | tty->driver_data = hp; | |
fb5c594c MO |
337 | tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */ |
338 | ||
1da177e4 LT |
339 | hp->tty = tty; |
340 | /* Save for request_irq outside of spin_lock. */ | |
341 | irq = hp->irq; | |
342 | if (irq != NO_IRQ) | |
343 | hp->irq_requested = 1; | |
344 | ||
345 | kobjp = &hp->kobj; | |
346 | ||
347 | spin_unlock_irqrestore(&hp->lock, flags); | |
348 | /* check error, fallback to non-irq */ | |
349 | if (irq != NO_IRQ) | |
350 | rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp); | |
351 | ||
352 | /* | |
353 | * If the request_irq() fails and we return an error. The tty layer | |
354 | * will call hvc_close() after a failed open but we don't want to clean | |
355 | * up there so we'll clean up here and clear out the previously set | |
356 | * tty fields and return the kobject reference. | |
357 | */ | |
358 | if (rc) { | |
359 | spin_lock_irqsave(&hp->lock, flags); | |
360 | hp->tty = NULL; | |
361 | hp->irq_requested = 0; | |
362 | spin_unlock_irqrestore(&hp->lock, flags); | |
363 | tty->driver_data = NULL; | |
364 | kobject_put(kobjp); | |
365 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); | |
366 | } | |
367 | /* Force wakeup of the polling thread */ | |
368 | hvc_kick(); | |
369 | ||
370 | return rc; | |
371 | } | |
372 | ||
373 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
374 | { | |
375 | struct hvc_struct *hp; | |
376 | struct kobject *kobjp; | |
377 | int irq = NO_IRQ; | |
378 | unsigned long flags; | |
379 | ||
380 | if (tty_hung_up_p(filp)) | |
381 | return; | |
382 | ||
383 | /* | |
384 | * No driver_data means that this close was issued after a failed | |
385 | * hvc_open by the tty layer's release_dev() function and we can just | |
386 | * exit cleanly because the kobject reference wasn't made. | |
387 | */ | |
388 | if (!tty->driver_data) | |
389 | return; | |
390 | ||
391 | hp = tty->driver_data; | |
392 | spin_lock_irqsave(&hp->lock, flags); | |
393 | ||
394 | kobjp = &hp->kobj; | |
395 | if (--hp->count == 0) { | |
396 | if (hp->irq_requested) | |
397 | irq = hp->irq; | |
398 | hp->irq_requested = 0; | |
399 | ||
400 | /* We are done with the tty pointer now. */ | |
401 | hp->tty = NULL; | |
402 | spin_unlock_irqrestore(&hp->lock, flags); | |
403 | ||
404 | /* | |
405 | * Chain calls chars_in_buffer() and returns immediately if | |
406 | * there is no buffered data otherwise sleeps on a wait queue | |
407 | * waking periodically to check chars_in_buffer(). | |
408 | */ | |
409 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
410 | ||
411 | if (irq != NO_IRQ) | |
412 | free_irq(irq, hp); | |
413 | ||
414 | } else { | |
415 | if (hp->count < 0) | |
416 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
417 | hp->vtermno, hp->count); | |
418 | spin_unlock_irqrestore(&hp->lock, flags); | |
419 | } | |
420 | ||
421 | kobject_put(kobjp); | |
422 | } | |
423 | ||
424 | static void hvc_hangup(struct tty_struct *tty) | |
425 | { | |
426 | struct hvc_struct *hp = tty->driver_data; | |
427 | unsigned long flags; | |
428 | int irq = NO_IRQ; | |
429 | int temp_open_count; | |
430 | struct kobject *kobjp; | |
431 | ||
432 | if (!hp) | |
433 | return; | |
434 | ||
435 | spin_lock_irqsave(&hp->lock, flags); | |
436 | ||
437 | /* | |
438 | * The N_TTY line discipline has problems such that in a close vs | |
439 | * open->hangup case this can be called after the final close so prevent | |
440 | * that from happening for now. | |
441 | */ | |
442 | if (hp->count <= 0) { | |
443 | spin_unlock_irqrestore(&hp->lock, flags); | |
444 | return; | |
445 | } | |
446 | ||
447 | kobjp = &hp->kobj; | |
448 | temp_open_count = hp->count; | |
449 | hp->count = 0; | |
450 | hp->n_outbuf = 0; | |
451 | hp->tty = NULL; | |
452 | if (hp->irq_requested) | |
453 | /* Saved for use outside of spin_lock. */ | |
454 | irq = hp->irq; | |
455 | hp->irq_requested = 0; | |
456 | spin_unlock_irqrestore(&hp->lock, flags); | |
457 | if (irq != NO_IRQ) | |
458 | free_irq(irq, hp); | |
459 | while(temp_open_count) { | |
460 | --temp_open_count; | |
461 | kobject_put(kobjp); | |
462 | } | |
463 | } | |
464 | ||
465 | /* | |
466 | * Push buffered characters whether they were just recently buffered or waiting | |
467 | * on a blocked hypervisor. Call this function with hp->lock held. | |
468 | */ | |
469 | static void hvc_push(struct hvc_struct *hp) | |
470 | { | |
471 | int n; | |
472 | ||
030ffad2 | 473 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 474 | if (n <= 0) { |
45d607ed RA |
475 | if (n == 0) { |
476 | hp->do_wakeup = 1; | |
1da177e4 | 477 | return; |
45d607ed | 478 | } |
1da177e4 LT |
479 | /* throw away output on error; this happens when |
480 | there is no session connected to the vterm. */ | |
481 | hp->n_outbuf = 0; | |
482 | } else | |
483 | hp->n_outbuf -= n; | |
484 | if (hp->n_outbuf > 0) | |
485 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
486 | else | |
487 | hp->do_wakeup = 1; | |
488 | } | |
489 | ||
45d607ed | 490 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 491 | { |
45d607ed | 492 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
493 | unsigned long flags; |
494 | int rsize, written = 0; | |
495 | ||
45d607ed RA |
496 | /* This write was probably executed during a tty close. */ |
497 | if (!hp) | |
498 | return -EPIPE; | |
499 | ||
500 | if (hp->count <= 0) | |
501 | return -EIO; | |
502 | ||
1da177e4 LT |
503 | spin_lock_irqsave(&hp->lock, flags); |
504 | ||
505 | /* Push pending writes */ | |
506 | if (hp->n_outbuf > 0) | |
507 | hvc_push(hp); | |
508 | ||
509 | while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { | |
510 | if (rsize > count) | |
511 | rsize = count; | |
512 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
513 | count -= rsize; | |
514 | buf += rsize; | |
515 | hp->n_outbuf += rsize; | |
516 | written += rsize; | |
517 | hvc_push(hp); | |
518 | } | |
519 | spin_unlock_irqrestore(&hp->lock, flags); | |
520 | ||
1da177e4 LT |
521 | /* |
522 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
523 | */ |
524 | if (hp->n_outbuf) | |
525 | hvc_kick(); | |
526 | ||
527 | return written; | |
528 | } | |
529 | ||
530 | /* | |
531 | * This is actually a contract between the driver and the tty layer outlining | |
532 | * how much write room the driver can guarentee will be sent OR BUFFERED. This | |
533 | * driver MUST honor the return value. | |
534 | */ | |
535 | static int hvc_write_room(struct tty_struct *tty) | |
536 | { | |
537 | struct hvc_struct *hp = tty->driver_data; | |
538 | ||
539 | if (!hp) | |
540 | return -1; | |
541 | ||
542 | return N_OUTBUF - hp->n_outbuf; | |
543 | } | |
544 | ||
545 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
546 | { | |
547 | struct hvc_struct *hp = tty->driver_data; | |
548 | ||
549 | if (!hp) | |
550 | return -1; | |
551 | return hp->n_outbuf; | |
552 | } | |
553 | ||
554 | #define HVC_POLL_READ 0x00000001 | |
555 | #define HVC_POLL_WRITE 0x00000002 | |
556 | #define HVC_POLL_QUICK 0x00000004 | |
557 | ||
558 | static int hvc_poll(struct hvc_struct *hp) | |
559 | { | |
560 | struct tty_struct *tty; | |
561 | int i, n, poll_mask = 0; | |
562 | char buf[N_INBUF] __ALIGNED__; | |
563 | unsigned long flags; | |
564 | int read_total = 0; | |
565 | ||
566 | spin_lock_irqsave(&hp->lock, flags); | |
567 | ||
568 | /* Push pending writes */ | |
569 | if (hp->n_outbuf > 0) | |
570 | hvc_push(hp); | |
571 | /* Reschedule us if still some write pending */ | |
572 | if (hp->n_outbuf > 0) | |
573 | poll_mask |= HVC_POLL_WRITE; | |
574 | ||
575 | /* No tty attached, just skip */ | |
576 | tty = hp->tty; | |
577 | if (tty == NULL) | |
578 | goto bail; | |
579 | ||
580 | /* Now check if we can get data (are we throttled ?) */ | |
581 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
582 | goto throttled; | |
583 | ||
584 | /* If we aren't interrupt driven and aren't throttled, we always | |
585 | * request a reschedule | |
586 | */ | |
587 | if (hp->irq == NO_IRQ) | |
588 | poll_mask |= HVC_POLL_READ; | |
589 | ||
590 | /* Read data if any */ | |
591 | for (;;) { | |
33f0f88f | 592 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
593 | |
594 | /* If flip is full, just reschedule a later read */ | |
595 | if (count == 0) { | |
596 | poll_mask |= HVC_POLL_READ; | |
597 | break; | |
598 | } | |
599 | ||
030ffad2 | 600 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
601 | if (n <= 0) { |
602 | /* Hangup the tty when disconnected from host */ | |
603 | if (n == -EPIPE) { | |
604 | spin_unlock_irqrestore(&hp->lock, flags); | |
605 | tty_hangup(tty); | |
606 | spin_lock_irqsave(&hp->lock, flags); | |
45d607ed RA |
607 | } else if ( n == -EAGAIN ) { |
608 | /* | |
609 | * Some back-ends can only ensure a certain min | |
610 | * num of bytes read, which may be > 'count'. | |
611 | * Let the tty clear the flip buff to make room. | |
612 | */ | |
613 | poll_mask |= HVC_POLL_READ; | |
1da177e4 LT |
614 | } |
615 | break; | |
616 | } | |
617 | for (i = 0; i < n; ++i) { | |
618 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
619 | if (hp->index == hvc_con_driver.index) { |
620 | /* Handle the SysRq Hack */ | |
621 | /* XXX should support a sequence */ | |
622 | if (buf[i] == '\x0f') { /* ^O */ | |
623 | sysrq_pressed = 1; | |
624 | continue; | |
625 | } else if (sysrq_pressed) { | |
626 | handle_sysrq(buf[i], NULL, tty); | |
627 | sysrq_pressed = 0; | |
628 | continue; | |
629 | } | |
1da177e4 LT |
630 | } |
631 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
632 | tty_insert_flip_char(tty, buf[i], 0); | |
633 | } | |
634 | ||
1da177e4 | 635 | read_total += n; |
1da177e4 LT |
636 | } |
637 | throttled: | |
638 | /* Wakeup write queue if necessary */ | |
639 | if (hp->do_wakeup) { | |
640 | hp->do_wakeup = 0; | |
641 | tty_wakeup(tty); | |
642 | } | |
643 | bail: | |
644 | spin_unlock_irqrestore(&hp->lock, flags); | |
645 | ||
fb5c594c MO |
646 | if (read_total) |
647 | tty_flip_buffer_push(tty); | |
648 | ||
1da177e4 LT |
649 | return poll_mask; |
650 | } | |
651 | ||
652 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
653 | extern cpumask_t cpus_in_xmon; | |
654 | #else | |
655 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
656 | #endif | |
657 | ||
658 | /* | |
659 | * This kthread is either polling or interrupt driven. This is determined by | |
660 | * calling hvc_poll() who determines whether a console adapter support | |
661 | * interrupts. | |
662 | */ | |
663 | int khvcd(void *unused) | |
664 | { | |
665 | int poll_mask; | |
666 | struct hvc_struct *hp; | |
667 | ||
668 | __set_current_state(TASK_RUNNING); | |
669 | do { | |
670 | poll_mask = 0; | |
671 | hvc_kicked = 0; | |
672 | wmb(); | |
673 | if (cpus_empty(cpus_in_xmon)) { | |
674 | spin_lock(&hvc_structs_lock); | |
675 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
676 | poll_mask |= hvc_poll(hp); |
677 | } | |
678 | spin_unlock(&hvc_structs_lock); | |
679 | } else | |
680 | poll_mask |= HVC_POLL_READ; | |
681 | if (hvc_kicked) | |
682 | continue; | |
683 | if (poll_mask & HVC_POLL_QUICK) { | |
684 | yield(); | |
685 | continue; | |
686 | } | |
687 | set_current_state(TASK_INTERRUPTIBLE); | |
688 | if (!hvc_kicked) { | |
689 | if (poll_mask == 0) | |
690 | schedule(); | |
691 | else | |
692 | msleep_interruptible(TIMEOUT); | |
693 | } | |
694 | __set_current_state(TASK_RUNNING); | |
695 | } while (!kthread_should_stop()); | |
696 | ||
697 | return 0; | |
698 | } | |
699 | ||
700 | static struct tty_operations hvc_ops = { | |
701 | .open = hvc_open, | |
702 | .close = hvc_close, | |
703 | .write = hvc_write, | |
704 | .hangup = hvc_hangup, | |
705 | .unthrottle = hvc_unthrottle, | |
706 | .write_room = hvc_write_room, | |
707 | .chars_in_buffer = hvc_chars_in_buffer, | |
708 | }; | |
709 | ||
1da177e4 LT |
710 | /* callback when the kboject ref count reaches zero. */ |
711 | static void destroy_hvc_struct(struct kobject *kobj) | |
712 | { | |
713 | struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); | |
714 | unsigned long flags; | |
715 | ||
716 | spin_lock(&hvc_structs_lock); | |
717 | ||
718 | spin_lock_irqsave(&hp->lock, flags); | |
719 | list_del(&(hp->next)); | |
720 | spin_unlock_irqrestore(&hp->lock, flags); | |
721 | ||
722 | spin_unlock(&hvc_structs_lock); | |
723 | ||
724 | kfree(hp); | |
725 | } | |
726 | ||
727 | static struct kobj_type hvc_kobj_type = { | |
728 | .release = destroy_hvc_struct, | |
729 | }; | |
730 | ||
030ffad2 MM |
731 | struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, |
732 | struct hv_ops *ops) | |
1da177e4 LT |
733 | { |
734 | struct hvc_struct *hp; | |
6f24808e | 735 | int i; |
1da177e4 | 736 | |
1da177e4 LT |
737 | hp = kmalloc(sizeof(*hp), GFP_KERNEL); |
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; |
1da177e4 LT |
746 | |
747 | kobject_init(&hp->kobj); | |
748 | hp->kobj.ktype = &hvc_kobj_type; | |
749 | ||
750 | spin_lock_init(&hp->lock); | |
751 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
752 | |
753 | /* | |
754 | * find index to use: | |
755 | * see if this vterm id matches one registered for console. | |
756 | */ | |
757 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
45d607ed RA |
758 | if (vtermnos[i] == hp->vtermno && |
759 | cons_ops[i] == hp->ops) | |
6f24808e MM |
760 | break; |
761 | ||
762 | /* no matching slot, just use a counter */ | |
763 | if (i >= MAX_NR_HVC_CONSOLES) | |
764 | i = ++last_hvc; | |
765 | ||
766 | hp->index = i; | |
767 | ||
1da177e4 LT |
768 | list_add_tail(&(hp->next), &hvc_structs); |
769 | spin_unlock(&hvc_structs_lock); | |
770 | ||
acad9559 | 771 | return hp; |
1da177e4 | 772 | } |
acad9559 | 773 | EXPORT_SYMBOL(hvc_alloc); |
1da177e4 | 774 | |
acad9559 | 775 | int __devexit hvc_remove(struct hvc_struct *hp) |
1da177e4 | 776 | { |
1da177e4 LT |
777 | unsigned long flags; |
778 | struct kobject *kobjp; | |
779 | struct tty_struct *tty; | |
780 | ||
781 | spin_lock_irqsave(&hp->lock, flags); | |
782 | tty = hp->tty; | |
783 | kobjp = &hp->kobj; | |
784 | ||
785 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
786 | vtermnos[hp->index] = -1; | |
787 | ||
788 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
789 | ||
790 | spin_unlock_irqrestore(&hp->lock, flags); | |
791 | ||
792 | /* | |
793 | * We 'put' the instance that was grabbed when the kobject instance | |
794 | * was intialized using kobject_init(). Let the last holder of this | |
795 | * kobject cause it to be removed, which will probably be the tty_hangup | |
796 | * below. | |
797 | */ | |
798 | kobject_put(kobjp); | |
799 | ||
800 | /* | |
801 | * This function call will auto chain call hvc_hangup. The tty should | |
802 | * always be valid at this time unless a simultaneous tty close already | |
803 | * cleaned up the hvc_struct. | |
804 | */ | |
805 | if (tty) | |
806 | tty_hangup(tty); | |
807 | return 0; | |
808 | } | |
acad9559 | 809 | EXPORT_SYMBOL(hvc_remove); |
1da177e4 LT |
810 | |
811 | /* Driver initialization. Follow console initialization. This is where the TTY | |
812 | * interfaces start to become available. */ | |
813 | int __init hvc_init(void) | |
814 | { | |
55aab8cd MN |
815 | struct tty_driver *drv; |
816 | ||
5f6d9c07 | 817 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd MN |
818 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
819 | if (!drv) | |
1da177e4 LT |
820 | return -ENOMEM; |
821 | ||
55aab8cd MN |
822 | drv->owner = THIS_MODULE; |
823 | drv->devfs_name = "hvc/"; | |
824 | drv->driver_name = "hvc"; | |
825 | drv->name = "hvc"; | |
826 | drv->major = HVC_MAJOR; | |
827 | drv->minor_start = HVC_MINOR; | |
828 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
829 | drv->init_termios = tty_std_termios; | |
830 | drv->flags = TTY_DRIVER_REAL_RAW; | |
831 | tty_set_operations(drv, &hvc_ops); | |
1da177e4 | 832 | |
1da177e4 LT |
833 | /* Always start the kthread because there can be hotplug vty adapters |
834 | * added later. */ | |
835 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
836 | if (IS_ERR(hvc_task)) { | |
837 | panic("Couldn't create kthread for console.\n"); | |
55aab8cd | 838 | put_tty_driver(drv); |
1da177e4 LT |
839 | return -EIO; |
840 | } | |
841 | ||
55aab8cd | 842 | if (tty_register_driver(drv)) |
ef4cbee0 AB |
843 | panic("Couldn't register hvc console driver\n"); |
844 | ||
55aab8cd MN |
845 | mb(); |
846 | hvc_driver = drv; | |
acad9559 | 847 | return 0; |
1da177e4 | 848 | } |
837dcfaf | 849 | module_init(hvc_init); |
1da177e4 | 850 | |
320da0d2 MM |
851 | /* This isn't particularily necessary due to this being a console driver |
852 | * but it is nice to be thorough. | |
853 | */ | |
1da177e4 LT |
854 | static void __exit hvc_exit(void) |
855 | { | |
856 | kthread_stop(hvc_task); | |
857 | ||
1da177e4 LT |
858 | tty_unregister_driver(hvc_driver); |
859 | /* return tty_struct instances allocated in hvc_init(). */ | |
860 | put_tty_driver(hvc_driver); | |
320da0d2 | 861 | unregister_console(&hvc_con_driver); |
1da177e4 | 862 | } |
1da177e4 | 863 | module_exit(hvc_exit); |