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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> | |
7dfb7103 | 41 | #include <linux/freezer.h> |
45d607ed | 42 | |
1da177e4 | 43 | #include <asm/uaccess.h> |
45d607ed RA |
44 | |
45 | #include "hvc_console.h" | |
1da177e4 LT |
46 | |
47 | #define HVC_MAJOR 229 | |
48 | #define HVC_MINOR 0 | |
49 | ||
1da177e4 LT |
50 | /* |
51 | * Wait this long per iteration while trying to push buffered data to the | |
52 | * hypervisor before allowing the tty to complete a close operation. | |
53 | */ | |
54 | #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ | |
55 | ||
56 | /* | |
45d607ed RA |
57 | * These sizes are most efficient for vio, because they are the |
58 | * native transfer size. We could make them selectable in the | |
59 | * future to better deal with backends that want other buffer sizes. | |
1da177e4 | 60 | */ |
1da177e4 LT |
61 | #define N_OUTBUF 16 |
62 | #define N_INBUF 16 | |
63 | ||
45d607ed | 64 | #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
1da177e4 | 65 | |
837dcfaf MM |
66 | static struct tty_driver *hvc_driver; |
67 | static struct task_struct *hvc_task; | |
68 | ||
69 | /* Picks up late kicks after list walk but before schedule() */ | |
70 | static int hvc_kicked; | |
71 | ||
72 | #ifdef CONFIG_MAGIC_SYSRQ | |
73 | static int sysrq_pressed; | |
74 | #endif | |
75 | ||
1da177e4 LT |
76 | struct hvc_struct { |
77 | spinlock_t lock; | |
78 | int index; | |
79 | struct tty_struct *tty; | |
80 | unsigned int count; | |
81 | int do_wakeup; | |
4e9e95a3 SR |
82 | char *outbuf; |
83 | int outbuf_size; | |
1da177e4 LT |
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 | |
c3ea6921 | 105 | * a console candidate registered with hvc_instantiate(). |
837dcfaf | 106 | */ |
6f24808e | 107 | static int last_hvc = -1; |
837dcfaf MM |
108 | |
109 | /* | |
c3ea6921 | 110 | * Do not call this function with either the hvc_structs_lock or the hvc_struct |
837dcfaf MM |
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 | */ | |
4fa156ea | 114 | static struct hvc_struct *hvc_get_by_index(int index) |
837dcfaf MM |
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 | ||
4fa156ea AB |
153 | static void hvc_console_print(struct console *co, const char *b, |
154 | unsigned count) | |
837dcfaf | 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 | ||
c3ea6921 | 164 | /* This console adapter was removed so it is not usable. */ |
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 | ||
4fa156ea | 212 | static struct console hvc_con_driver = { |
837dcfaf MM |
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 | 221 | /* |
c3ea6921 | 222 | * Early console initialization. Precedes driver initialization. |
d5ee257c MM |
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 | ||
c3ea6921 | 259 | /* make sure no no tty has been registered in this index */ |
7805b1b2 MM |
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 | 268 | |
c3ea6921 | 269 | /* reserve all indices up to and including this index */ |
6f24808e MM |
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 | } | |
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 | */ | |
7d12e780 | 296 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance) |
1da177e4 | 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; | |
8cd0ae05 | 317 | int irq = 0; |
1da177e4 LT |
318 | int rc = 0; |
319 | struct kobject *kobjp; | |
320 | ||
321 | /* Auto increments kobject reference if found. */ | |
87fd7724 | 322 | if (!(hp = hvc_get_by_index(tty->index))) |
1da177e4 | 323 | return -ENODEV; |
1da177e4 LT |
324 | |
325 | spin_lock_irqsave(&hp->lock, flags); | |
326 | /* Check and then increment for fast path open. */ | |
327 | if (hp->count++ > 0) { | |
328 | spin_unlock_irqrestore(&hp->lock, flags); | |
329 | hvc_kick(); | |
330 | return 0; | |
331 | } /* else count == 0 */ | |
332 | ||
333 | tty->driver_data = hp; | |
fb5c594c MO |
334 | tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */ |
335 | ||
1da177e4 LT |
336 | hp->tty = tty; |
337 | /* Save for request_irq outside of spin_lock. */ | |
338 | irq = hp->irq; | |
8cd0ae05 | 339 | if (irq) |
1da177e4 LT |
340 | hp->irq_requested = 1; |
341 | ||
342 | kobjp = &hp->kobj; | |
343 | ||
344 | spin_unlock_irqrestore(&hp->lock, flags); | |
345 | /* check error, fallback to non-irq */ | |
8cd0ae05 | 346 | if (irq) |
0f2ed4c6 | 347 | rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED, "hvc_console", hp); |
1da177e4 LT |
348 | |
349 | /* | |
350 | * If the request_irq() fails and we return an error. The tty layer | |
351 | * will call hvc_close() after a failed open but we don't want to clean | |
352 | * up there so we'll clean up here and clear out the previously set | |
353 | * tty fields and return the kobject reference. | |
354 | */ | |
355 | if (rc) { | |
356 | spin_lock_irqsave(&hp->lock, flags); | |
357 | hp->tty = NULL; | |
358 | hp->irq_requested = 0; | |
359 | spin_unlock_irqrestore(&hp->lock, flags); | |
360 | tty->driver_data = NULL; | |
361 | kobject_put(kobjp); | |
362 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); | |
363 | } | |
364 | /* Force wakeup of the polling thread */ | |
365 | hvc_kick(); | |
366 | ||
367 | return rc; | |
368 | } | |
369 | ||
370 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
371 | { | |
372 | struct hvc_struct *hp; | |
373 | struct kobject *kobjp; | |
8cd0ae05 | 374 | int irq = 0; |
1da177e4 LT |
375 | unsigned long flags; |
376 | ||
377 | if (tty_hung_up_p(filp)) | |
378 | return; | |
379 | ||
380 | /* | |
381 | * No driver_data means that this close was issued after a failed | |
382 | * hvc_open by the tty layer's release_dev() function and we can just | |
383 | * exit cleanly because the kobject reference wasn't made. | |
384 | */ | |
385 | if (!tty->driver_data) | |
386 | return; | |
387 | ||
388 | hp = tty->driver_data; | |
389 | spin_lock_irqsave(&hp->lock, flags); | |
390 | ||
391 | kobjp = &hp->kobj; | |
392 | if (--hp->count == 0) { | |
393 | if (hp->irq_requested) | |
394 | irq = hp->irq; | |
395 | hp->irq_requested = 0; | |
396 | ||
397 | /* We are done with the tty pointer now. */ | |
398 | hp->tty = NULL; | |
399 | spin_unlock_irqrestore(&hp->lock, flags); | |
400 | ||
401 | /* | |
402 | * Chain calls chars_in_buffer() and returns immediately if | |
403 | * there is no buffered data otherwise sleeps on a wait queue | |
404 | * waking periodically to check chars_in_buffer(). | |
405 | */ | |
406 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
407 | ||
8cd0ae05 | 408 | if (irq) |
1da177e4 LT |
409 | free_irq(irq, hp); |
410 | ||
411 | } else { | |
412 | if (hp->count < 0) | |
413 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
414 | hp->vtermno, hp->count); | |
415 | spin_unlock_irqrestore(&hp->lock, flags); | |
416 | } | |
417 | ||
418 | kobject_put(kobjp); | |
419 | } | |
420 | ||
421 | static void hvc_hangup(struct tty_struct *tty) | |
422 | { | |
423 | struct hvc_struct *hp = tty->driver_data; | |
424 | unsigned long flags; | |
8cd0ae05 | 425 | int irq = 0; |
1da177e4 LT |
426 | int temp_open_count; |
427 | struct kobject *kobjp; | |
428 | ||
429 | if (!hp) | |
430 | return; | |
431 | ||
432 | spin_lock_irqsave(&hp->lock, flags); | |
433 | ||
434 | /* | |
435 | * The N_TTY line discipline has problems such that in a close vs | |
436 | * open->hangup case this can be called after the final close so prevent | |
437 | * that from happening for now. | |
438 | */ | |
439 | if (hp->count <= 0) { | |
440 | spin_unlock_irqrestore(&hp->lock, flags); | |
441 | return; | |
442 | } | |
443 | ||
444 | kobjp = &hp->kobj; | |
445 | temp_open_count = hp->count; | |
446 | hp->count = 0; | |
447 | hp->n_outbuf = 0; | |
448 | hp->tty = NULL; | |
449 | if (hp->irq_requested) | |
450 | /* Saved for use outside of spin_lock. */ | |
451 | irq = hp->irq; | |
452 | hp->irq_requested = 0; | |
453 | spin_unlock_irqrestore(&hp->lock, flags); | |
8cd0ae05 | 454 | if (irq) |
1da177e4 LT |
455 | free_irq(irq, hp); |
456 | while(temp_open_count) { | |
457 | --temp_open_count; | |
458 | kobject_put(kobjp); | |
459 | } | |
460 | } | |
461 | ||
462 | /* | |
463 | * Push buffered characters whether they were just recently buffered or waiting | |
464 | * on a blocked hypervisor. Call this function with hp->lock held. | |
465 | */ | |
466 | static void hvc_push(struct hvc_struct *hp) | |
467 | { | |
468 | int n; | |
469 | ||
030ffad2 | 470 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 471 | if (n <= 0) { |
45d607ed RA |
472 | if (n == 0) { |
473 | hp->do_wakeup = 1; | |
1da177e4 | 474 | return; |
45d607ed | 475 | } |
1da177e4 LT |
476 | /* throw away output on error; this happens when |
477 | there is no session connected to the vterm. */ | |
478 | hp->n_outbuf = 0; | |
479 | } else | |
480 | hp->n_outbuf -= n; | |
481 | if (hp->n_outbuf > 0) | |
482 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
483 | else | |
484 | hp->do_wakeup = 1; | |
485 | } | |
486 | ||
45d607ed | 487 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 488 | { |
45d607ed | 489 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
490 | unsigned long flags; |
491 | int rsize, written = 0; | |
492 | ||
45d607ed RA |
493 | /* This write was probably executed during a tty close. */ |
494 | if (!hp) | |
495 | return -EPIPE; | |
496 | ||
497 | if (hp->count <= 0) | |
498 | return -EIO; | |
499 | ||
1da177e4 LT |
500 | spin_lock_irqsave(&hp->lock, flags); |
501 | ||
502 | /* Push pending writes */ | |
503 | if (hp->n_outbuf > 0) | |
504 | hvc_push(hp); | |
505 | ||
4e9e95a3 | 506 | while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { |
1da177e4 LT |
507 | if (rsize > count) |
508 | rsize = count; | |
509 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
510 | count -= rsize; | |
511 | buf += rsize; | |
512 | hp->n_outbuf += rsize; | |
513 | written += rsize; | |
514 | hvc_push(hp); | |
515 | } | |
516 | spin_unlock_irqrestore(&hp->lock, flags); | |
517 | ||
1da177e4 LT |
518 | /* |
519 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
520 | */ |
521 | if (hp->n_outbuf) | |
522 | hvc_kick(); | |
523 | ||
524 | return written; | |
525 | } | |
526 | ||
527 | /* | |
528 | * This is actually a contract between the driver and the tty layer outlining | |
c3ea6921 | 529 | * how much write room the driver can guarantee will be sent OR BUFFERED. This |
1da177e4 LT |
530 | * driver MUST honor the return value. |
531 | */ | |
532 | static int hvc_write_room(struct tty_struct *tty) | |
533 | { | |
534 | struct hvc_struct *hp = tty->driver_data; | |
535 | ||
536 | if (!hp) | |
537 | return -1; | |
538 | ||
4e9e95a3 | 539 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
540 | } |
541 | ||
542 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
543 | { | |
544 | struct hvc_struct *hp = tty->driver_data; | |
545 | ||
546 | if (!hp) | |
547 | return -1; | |
548 | return hp->n_outbuf; | |
549 | } | |
550 | ||
b791072b WS |
551 | /* |
552 | * timeout will vary between the MIN and MAX values defined here. By default | |
553 | * and during console activity we will use a default MIN_TIMEOUT of 10. When | |
554 | * the console is idle, we increase the timeout value on each pass through | |
555 | * msleep until we reach the max. This may be noticeable as a brief (average | |
556 | * one second) delay on the console before the console responds to input when | |
557 | * there has been no input for some time. | |
558 | */ | |
559 | #define MIN_TIMEOUT (10) | |
560 | #define MAX_TIMEOUT (2000) | |
561 | static u32 timeout = MIN_TIMEOUT; | |
562 | ||
1da177e4 LT |
563 | #define HVC_POLL_READ 0x00000001 |
564 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 LT |
565 | |
566 | static int hvc_poll(struct hvc_struct *hp) | |
567 | { | |
568 | struct tty_struct *tty; | |
569 | int i, n, poll_mask = 0; | |
570 | char buf[N_INBUF] __ALIGNED__; | |
571 | unsigned long flags; | |
572 | int read_total = 0; | |
573 | ||
574 | spin_lock_irqsave(&hp->lock, flags); | |
575 | ||
576 | /* Push pending writes */ | |
577 | if (hp->n_outbuf > 0) | |
578 | hvc_push(hp); | |
b5374461 | 579 | |
1da177e4 LT |
580 | /* Reschedule us if still some write pending */ |
581 | if (hp->n_outbuf > 0) | |
582 | poll_mask |= HVC_POLL_WRITE; | |
583 | ||
584 | /* No tty attached, just skip */ | |
585 | tty = hp->tty; | |
586 | if (tty == NULL) | |
587 | goto bail; | |
588 | ||
589 | /* Now check if we can get data (are we throttled ?) */ | |
590 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
591 | goto throttled; | |
592 | ||
593 | /* If we aren't interrupt driven and aren't throttled, we always | |
594 | * request a reschedule | |
595 | */ | |
8cd0ae05 | 596 | if (hp->irq == 0) |
1da177e4 LT |
597 | poll_mask |= HVC_POLL_READ; |
598 | ||
599 | /* Read data if any */ | |
600 | for (;;) { | |
33f0f88f | 601 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
602 | |
603 | /* If flip is full, just reschedule a later read */ | |
604 | if (count == 0) { | |
605 | poll_mask |= HVC_POLL_READ; | |
606 | break; | |
607 | } | |
608 | ||
030ffad2 | 609 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
610 | if (n <= 0) { |
611 | /* Hangup the tty when disconnected from host */ | |
612 | if (n == -EPIPE) { | |
613 | spin_unlock_irqrestore(&hp->lock, flags); | |
614 | tty_hangup(tty); | |
615 | spin_lock_irqsave(&hp->lock, flags); | |
45d607ed RA |
616 | } else if ( n == -EAGAIN ) { |
617 | /* | |
618 | * Some back-ends can only ensure a certain min | |
619 | * num of bytes read, which may be > 'count'. | |
620 | * Let the tty clear the flip buff to make room. | |
621 | */ | |
622 | poll_mask |= HVC_POLL_READ; | |
1da177e4 LT |
623 | } |
624 | break; | |
625 | } | |
626 | for (i = 0; i < n; ++i) { | |
627 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
628 | if (hp->index == hvc_con_driver.index) { |
629 | /* Handle the SysRq Hack */ | |
630 | /* XXX should support a sequence */ | |
631 | if (buf[i] == '\x0f') { /* ^O */ | |
632 | sysrq_pressed = 1; | |
633 | continue; | |
634 | } else if (sysrq_pressed) { | |
7d12e780 | 635 | handle_sysrq(buf[i], tty); |
2b9e0bac MM |
636 | sysrq_pressed = 0; |
637 | continue; | |
638 | } | |
1da177e4 LT |
639 | } |
640 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
641 | tty_insert_flip_char(tty, buf[i], 0); | |
642 | } | |
643 | ||
1da177e4 | 644 | read_total += n; |
1da177e4 LT |
645 | } |
646 | throttled: | |
647 | /* Wakeup write queue if necessary */ | |
648 | if (hp->do_wakeup) { | |
649 | hp->do_wakeup = 0; | |
650 | tty_wakeup(tty); | |
651 | } | |
652 | bail: | |
653 | spin_unlock_irqrestore(&hp->lock, flags); | |
654 | ||
b791072b WS |
655 | if (read_total) { |
656 | /* Activity is occurring, so reset the polling backoff value to | |
657 | a minimum for performance. */ | |
658 | timeout = MIN_TIMEOUT; | |
659 | ||
fb5c594c | 660 | tty_flip_buffer_push(tty); |
b791072b WS |
661 | } |
662 | ||
1da177e4 LT |
663 | return poll_mask; |
664 | } | |
665 | ||
666 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
667 | extern cpumask_t cpus_in_xmon; | |
668 | #else | |
669 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
670 | #endif | |
671 | ||
672 | /* | |
673 | * This kthread is either polling or interrupt driven. This is determined by | |
674 | * calling hvc_poll() who determines whether a console adapter support | |
675 | * interrupts. | |
676 | */ | |
5605d4de | 677 | static int khvcd(void *unused) |
1da177e4 LT |
678 | { |
679 | int poll_mask; | |
680 | struct hvc_struct *hp; | |
681 | ||
83144186 | 682 | set_freezable(); |
1da177e4 LT |
683 | __set_current_state(TASK_RUNNING); |
684 | do { | |
685 | poll_mask = 0; | |
686 | hvc_kicked = 0; | |
b64074e4 | 687 | try_to_freeze(); |
1da177e4 LT |
688 | wmb(); |
689 | if (cpus_empty(cpus_in_xmon)) { | |
690 | spin_lock(&hvc_structs_lock); | |
691 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
692 | poll_mask |= hvc_poll(hp); |
693 | } | |
694 | spin_unlock(&hvc_structs_lock); | |
695 | } else | |
696 | poll_mask |= HVC_POLL_READ; | |
697 | if (hvc_kicked) | |
698 | continue; | |
b5374461 | 699 | if (poll_mask & HVC_POLL_WRITE) { |
1da177e4 LT |
700 | yield(); |
701 | continue; | |
702 | } | |
703 | set_current_state(TASK_INTERRUPTIBLE); | |
704 | if (!hvc_kicked) { | |
705 | if (poll_mask == 0) | |
706 | schedule(); | |
b791072b WS |
707 | else { |
708 | if (timeout < MAX_TIMEOUT) | |
709 | timeout += (timeout >> 6) + 1; | |
710 | ||
711 | msleep_interruptible(timeout); | |
712 | } | |
1da177e4 LT |
713 | } |
714 | __set_current_state(TASK_RUNNING); | |
715 | } while (!kthread_should_stop()); | |
716 | ||
717 | return 0; | |
718 | } | |
719 | ||
b68e31d0 | 720 | static const struct tty_operations hvc_ops = { |
1da177e4 LT |
721 | .open = hvc_open, |
722 | .close = hvc_close, | |
723 | .write = hvc_write, | |
724 | .hangup = hvc_hangup, | |
725 | .unthrottle = hvc_unthrottle, | |
726 | .write_room = hvc_write_room, | |
727 | .chars_in_buffer = hvc_chars_in_buffer, | |
728 | }; | |
729 | ||
1da177e4 LT |
730 | /* callback when the kboject ref count reaches zero. */ |
731 | static void destroy_hvc_struct(struct kobject *kobj) | |
732 | { | |
733 | struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); | |
734 | unsigned long flags; | |
735 | ||
736 | spin_lock(&hvc_structs_lock); | |
737 | ||
738 | spin_lock_irqsave(&hp->lock, flags); | |
739 | list_del(&(hp->next)); | |
740 | spin_unlock_irqrestore(&hp->lock, flags); | |
741 | ||
742 | spin_unlock(&hvc_structs_lock); | |
743 | ||
744 | kfree(hp); | |
745 | } | |
746 | ||
747 | static struct kobj_type hvc_kobj_type = { | |
748 | .release = destroy_hvc_struct, | |
749 | }; | |
750 | ||
030ffad2 | 751 | struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, |
4e9e95a3 | 752 | struct hv_ops *ops, int outbuf_size) |
1da177e4 LT |
753 | { |
754 | struct hvc_struct *hp; | |
6f24808e | 755 | int i; |
1da177e4 | 756 | |
4e9e95a3 SR |
757 | hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
758 | GFP_KERNEL); | |
1da177e4 | 759 | if (!hp) |
acad9559 | 760 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
761 | |
762 | memset(hp, 0x00, sizeof(*hp)); | |
acad9559 MM |
763 | |
764 | hp->vtermno = vtermno; | |
765 | hp->irq = irq; | |
030ffad2 | 766 | hp->ops = ops; |
4e9e95a3 SR |
767 | hp->outbuf_size = outbuf_size; |
768 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 LT |
769 | |
770 | kobject_init(&hp->kobj); | |
771 | hp->kobj.ktype = &hvc_kobj_type; | |
772 | ||
773 | spin_lock_init(&hp->lock); | |
774 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
775 | |
776 | /* | |
777 | * find index to use: | |
778 | * see if this vterm id matches one registered for console. | |
779 | */ | |
780 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
45d607ed RA |
781 | if (vtermnos[i] == hp->vtermno && |
782 | cons_ops[i] == hp->ops) | |
6f24808e MM |
783 | break; |
784 | ||
785 | /* no matching slot, just use a counter */ | |
786 | if (i >= MAX_NR_HVC_CONSOLES) | |
787 | i = ++last_hvc; | |
788 | ||
789 | hp->index = i; | |
790 | ||
1da177e4 LT |
791 | list_add_tail(&(hp->next), &hvc_structs); |
792 | spin_unlock(&hvc_structs_lock); | |
793 | ||
acad9559 | 794 | return hp; |
1da177e4 LT |
795 | } |
796 | ||
acad9559 | 797 | int __devexit hvc_remove(struct hvc_struct *hp) |
1da177e4 | 798 | { |
1da177e4 LT |
799 | unsigned long flags; |
800 | struct kobject *kobjp; | |
801 | struct tty_struct *tty; | |
802 | ||
803 | spin_lock_irqsave(&hp->lock, flags); | |
804 | tty = hp->tty; | |
805 | kobjp = &hp->kobj; | |
806 | ||
807 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
808 | vtermnos[hp->index] = -1; | |
809 | ||
810 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
811 | ||
812 | spin_unlock_irqrestore(&hp->lock, flags); | |
813 | ||
814 | /* | |
815 | * We 'put' the instance that was grabbed when the kobject instance | |
c3ea6921 | 816 | * was initialized using kobject_init(). Let the last holder of this |
1da177e4 LT |
817 | * kobject cause it to be removed, which will probably be the tty_hangup |
818 | * below. | |
819 | */ | |
820 | kobject_put(kobjp); | |
821 | ||
822 | /* | |
823 | * This function call will auto chain call hvc_hangup. The tty should | |
824 | * always be valid at this time unless a simultaneous tty close already | |
825 | * cleaned up the hvc_struct. | |
826 | */ | |
827 | if (tty) | |
828 | tty_hangup(tty); | |
829 | return 0; | |
830 | } | |
1da177e4 LT |
831 | |
832 | /* Driver initialization. Follow console initialization. This is where the TTY | |
833 | * interfaces start to become available. */ | |
4fa156ea | 834 | static int __init hvc_init(void) |
1da177e4 | 835 | { |
55aab8cd MN |
836 | struct tty_driver *drv; |
837 | ||
5f6d9c07 | 838 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd MN |
839 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
840 | if (!drv) | |
1da177e4 LT |
841 | return -ENOMEM; |
842 | ||
55aab8cd | 843 | drv->owner = THIS_MODULE; |
55aab8cd MN |
844 | drv->driver_name = "hvc"; |
845 | drv->name = "hvc"; | |
846 | drv->major = HVC_MAJOR; | |
847 | drv->minor_start = HVC_MINOR; | |
848 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
849 | drv->init_termios = tty_std_termios; | |
850 | drv->flags = TTY_DRIVER_REAL_RAW; | |
851 | tty_set_operations(drv, &hvc_ops); | |
1da177e4 | 852 | |
1da177e4 LT |
853 | /* Always start the kthread because there can be hotplug vty adapters |
854 | * added later. */ | |
855 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
856 | if (IS_ERR(hvc_task)) { | |
857 | panic("Couldn't create kthread for console.\n"); | |
55aab8cd | 858 | put_tty_driver(drv); |
1da177e4 LT |
859 | return -EIO; |
860 | } | |
861 | ||
55aab8cd | 862 | if (tty_register_driver(drv)) |
ef4cbee0 AB |
863 | panic("Couldn't register hvc console driver\n"); |
864 | ||
55aab8cd MN |
865 | mb(); |
866 | hvc_driver = drv; | |
acad9559 | 867 | return 0; |
1da177e4 | 868 | } |
837dcfaf | 869 | module_init(hvc_init); |
1da177e4 | 870 | |
c3ea6921 | 871 | /* This isn't particularly necessary due to this being a console driver |
320da0d2 MM |
872 | * but it is nice to be thorough. |
873 | */ | |
1da177e4 LT |
874 | static void __exit hvc_exit(void) |
875 | { | |
876 | kthread_stop(hvc_task); | |
877 | ||
1da177e4 LT |
878 | tty_unregister_driver(hvc_driver); |
879 | /* return tty_struct instances allocated in hvc_init(). */ | |
880 | put_tty_driver(hvc_driver); | |
320da0d2 | 881 | unregister_console(&hvc_con_driver); |
1da177e4 | 882 | } |
1da177e4 | 883 | module_exit(hvc_exit); |