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