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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> | |
42 | #include <asm/uaccess.h> | |
43 | #include <asm/hvconsole.h> | |
1da177e4 LT |
44 | |
45 | #define HVC_MAJOR 229 | |
46 | #define HVC_MINOR 0 | |
47 | ||
48 | #define TIMEOUT (10) | |
49 | ||
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 | /* | |
57 | * The Linux TTY code does not support dynamic addition of tty derived devices | |
58 | * so we need to know how many tty devices we might need when space is allocated | |
59 | * for the tty device. Since this driver supports hotplug of vty adapters we | |
60 | * need to make sure we have enough allocated. | |
61 | */ | |
62 | #define HVC_ALLOC_TTY_ADAPTERS 8 | |
63 | ||
1da177e4 LT |
64 | #define N_OUTBUF 16 |
65 | #define N_INBUF 16 | |
66 | ||
67 | #define __ALIGNED__ __attribute__((__aligned__(8))) | |
68 | ||
837dcfaf MM |
69 | static struct tty_driver *hvc_driver; |
70 | static struct task_struct *hvc_task; | |
71 | ||
72 | /* Picks up late kicks after list walk but before schedule() */ | |
73 | static int hvc_kicked; | |
74 | ||
75 | #ifdef CONFIG_MAGIC_SYSRQ | |
76 | static int sysrq_pressed; | |
77 | #endif | |
78 | ||
1da177e4 LT |
79 | struct hvc_struct { |
80 | spinlock_t lock; | |
81 | int index; | |
82 | struct tty_struct *tty; | |
83 | unsigned int count; | |
84 | int do_wakeup; | |
85 | char outbuf[N_OUTBUF] __ALIGNED__; | |
86 | int n_outbuf; | |
87 | uint32_t vtermno; | |
030ffad2 | 88 | struct hv_ops *ops; |
1da177e4 LT |
89 | int irq_requested; |
90 | int irq; | |
91 | struct list_head next; | |
92 | struct kobject kobj; /* ref count & hvc_struct lifetime */ | |
1da177e4 LT |
93 | }; |
94 | ||
95 | /* dynamic list of hvc_struct instances */ | |
96 | static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs); | |
97 | ||
98 | /* | |
99 | * Protect the list of hvc_struct instances from inserts and removals during | |
100 | * list traversal. | |
101 | */ | |
102 | static DEFINE_SPINLOCK(hvc_structs_lock); | |
103 | ||
837dcfaf | 104 | /* |
6f24808e MM |
105 | * This value is used to assign a tty->index value to a hvc_struct based |
106 | * upon order of exposure via hvc_probe(), when we can not match it to | |
107 | * a console canidate registered with hvc_instantiate(). | |
837dcfaf | 108 | */ |
6f24808e | 109 | static int last_hvc = -1; |
837dcfaf MM |
110 | |
111 | /* | |
112 | * Do not call this function with either the hvc_strucst_lock or the hvc_struct | |
113 | * lock held. If successful, this function increments the kobject reference | |
114 | * count against the target hvc_struct so it should be released when finished. | |
115 | */ | |
116 | struct hvc_struct *hvc_get_by_index(int index) | |
117 | { | |
118 | struct hvc_struct *hp; | |
119 | unsigned long flags; | |
120 | ||
121 | spin_lock(&hvc_structs_lock); | |
122 | ||
123 | list_for_each_entry(hp, &hvc_structs, next) { | |
124 | spin_lock_irqsave(&hp->lock, flags); | |
125 | if (hp->index == index) { | |
126 | kobject_get(&hp->kobj); | |
127 | spin_unlock_irqrestore(&hp->lock, flags); | |
128 | spin_unlock(&hvc_structs_lock); | |
129 | return hp; | |
130 | } | |
131 | spin_unlock_irqrestore(&hp->lock, flags); | |
132 | } | |
133 | hp = NULL; | |
134 | ||
135 | spin_unlock(&hvc_structs_lock); | |
136 | return hp; | |
137 | } | |
138 | ||
139 | ||
1da177e4 LT |
140 | /* |
141 | * Initial console vtermnos for console API usage prior to full console | |
142 | * initialization. Any vty adapter outside this range will not have usable | |
143 | * console interfaces but can still be used as a tty device. This has to be | |
144 | * static because kmalloc will not work during early console init. | |
145 | */ | |
030ffad2 | 146 | static struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
64e4da57 MM |
147 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
148 | {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; | |
1da177e4 | 149 | |
837dcfaf MM |
150 | /* |
151 | * Console APIs, NOT TTY. These APIs are available immediately when | |
152 | * hvc_console_setup() finds adapters. | |
153 | */ | |
154 | ||
155 | void hvc_console_print(struct console *co, const char *b, unsigned count) | |
156 | { | |
157 | char c[16] __ALIGNED__; | |
158 | unsigned i = 0, n = 0; | |
030ffad2 | 159 | int r, donecr = 0, index = co->index; |
837dcfaf MM |
160 | |
161 | /* Console access attempt outside of acceptable console range. */ | |
030ffad2 | 162 | if (index >= MAX_NR_HVC_CONSOLES) |
837dcfaf MM |
163 | return; |
164 | ||
165 | /* This console adapter was removed so it is not useable. */ | |
030ffad2 | 166 | if (vtermnos[index] < 0) |
837dcfaf MM |
167 | return; |
168 | ||
169 | while (count > 0 || i > 0) { | |
170 | if (count > 0 && i < sizeof(c)) { | |
171 | if (b[n] == '\n' && !donecr) { | |
172 | c[i++] = '\r'; | |
173 | donecr = 1; | |
174 | } else { | |
175 | c[i++] = b[n++]; | |
176 | donecr = 0; | |
177 | --count; | |
178 | } | |
179 | } else { | |
030ffad2 | 180 | r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
837dcfaf MM |
181 | if (r < 0) { |
182 | /* throw away chars on error */ | |
183 | i = 0; | |
184 | } else if (r > 0) { | |
185 | i -= r; | |
186 | if (i > 0) | |
187 | memmove(c, c+r, i); | |
188 | } | |
189 | } | |
190 | } | |
191 | } | |
192 | ||
193 | static struct tty_driver *hvc_console_device(struct console *c, int *index) | |
194 | { | |
7805b1b2 MM |
195 | if (vtermnos[c->index] == -1) |
196 | return NULL; | |
197 | ||
837dcfaf MM |
198 | *index = c->index; |
199 | return hvc_driver; | |
200 | } | |
201 | ||
202 | static int __init hvc_console_setup(struct console *co, char *options) | |
203 | { | |
7805b1b2 MM |
204 | if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
205 | return -ENODEV; | |
206 | ||
207 | if (vtermnos[co->index] == -1) | |
208 | return -ENODEV; | |
209 | ||
837dcfaf MM |
210 | return 0; |
211 | } | |
212 | ||
213 | struct console hvc_con_driver = { | |
214 | .name = "hvc", | |
215 | .write = hvc_console_print, | |
216 | .device = hvc_console_device, | |
217 | .setup = hvc_console_setup, | |
218 | .flags = CON_PRINTBUFFER, | |
219 | .index = -1, | |
220 | }; | |
221 | ||
d5ee257c MM |
222 | /* |
223 | * Early console initialization. Preceeds driver initialization. | |
224 | * | |
225 | * (1) we are first, and the user specified another driver | |
226 | * -- index will remain -1 | |
227 | * (2) we are first and the user specified no driver | |
228 | * -- index will be set to 0, then we will fail setup. | |
229 | * (3) we are first and the user specified our driver | |
230 | * -- index will be set to user specified driver, and we will fail | |
231 | * (4) we are after driver, and this initcall will register us | |
232 | * -- if the user didn't specify a driver then the console will match | |
233 | * | |
234 | * Note that for cases 2 and 3, we will match later when the io driver | |
235 | * calls hvc_instantiate() and call register again. | |
236 | */ | |
837dcfaf MM |
237 | static int __init hvc_console_init(void) |
238 | { | |
837dcfaf MM |
239 | register_console(&hvc_con_driver); |
240 | return 0; | |
241 | } | |
242 | console_initcall(hvc_console_init); | |
1da177e4 LT |
243 | |
244 | /* | |
6f24808e MM |
245 | * hvc_instantiate() is an early console discovery method which locates |
246 | * consoles * prior to the vio subsystem discovering them. Hotplugged | |
247 | * vty adapters do NOT get an hvc_instantiate() callback since they | |
248 | * appear after early console init. | |
1da177e4 | 249 | */ |
030ffad2 | 250 | int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops) |
837dcfaf | 251 | { |
7805b1b2 MM |
252 | struct hvc_struct *hp; |
253 | ||
837dcfaf MM |
254 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
255 | return -1; | |
1da177e4 | 256 | |
837dcfaf MM |
257 | if (vtermnos[index] != -1) |
258 | return -1; | |
259 | ||
7805b1b2 MM |
260 | /* make sure no no tty has been registerd in this index */ |
261 | hp = hvc_get_by_index(index); | |
262 | if (hp) { | |
263 | kobject_put(&hp->kobj); | |
264 | return -1; | |
265 | } | |
266 | ||
837dcfaf | 267 | vtermnos[index] = vtermno; |
030ffad2 | 268 | cons_ops[index] = ops; |
6f24808e MM |
269 | |
270 | /* reserve all indices upto and including this index */ | |
271 | if (last_hvc < index) | |
272 | last_hvc = index; | |
273 | ||
d5ee257c MM |
274 | /* if this index is what the user requested, then register |
275 | * now (setup won't fail at this point). It's ok to just | |
276 | * call register again if previously .setup failed. | |
277 | */ | |
278 | if (index == hvc_con_driver.index) | |
279 | register_console(&hvc_con_driver); | |
280 | ||
837dcfaf MM |
281 | return 0; |
282 | } | |
acad9559 | 283 | EXPORT_SYMBOL(hvc_instantiate); |
1da177e4 LT |
284 | |
285 | /* Wake the sleeping khvcd */ | |
286 | static void hvc_kick(void) | |
287 | { | |
288 | hvc_kicked = 1; | |
289 | wake_up_process(hvc_task); | |
290 | } | |
291 | ||
8b67f8c1 MM |
292 | static int hvc_poll(struct hvc_struct *hp); |
293 | ||
1da177e4 LT |
294 | /* |
295 | * NOTE: This API isn't used if the console adapter doesn't support interrupts. | |
296 | * In this case the console is poll driven. | |
297 | */ | |
298 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs) | |
299 | { | |
8b67f8c1 MM |
300 | /* if hvc_poll request a repoll, then kick the hvcd thread */ |
301 | if (hvc_poll(dev_instance)) | |
302 | hvc_kick(); | |
1da177e4 LT |
303 | return IRQ_HANDLED; |
304 | } | |
305 | ||
306 | static void hvc_unthrottle(struct tty_struct *tty) | |
307 | { | |
308 | hvc_kick(); | |
309 | } | |
310 | ||
1da177e4 LT |
311 | /* |
312 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
313 | * adapter to the kernel. | |
314 | */ | |
315 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
316 | { | |
317 | struct hvc_struct *hp; | |
318 | unsigned long flags; | |
319 | int irq = NO_IRQ; | |
320 | int rc = 0; | |
321 | struct kobject *kobjp; | |
322 | ||
323 | /* Auto increments kobject reference if found. */ | |
324 | if (!(hp = hvc_get_by_index(tty->index))) { | |
325 | printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n"); | |
326 | return -ENODEV; | |
327 | } | |
328 | ||
329 | spin_lock_irqsave(&hp->lock, flags); | |
330 | /* Check and then increment for fast path open. */ | |
331 | if (hp->count++ > 0) { | |
332 | spin_unlock_irqrestore(&hp->lock, flags); | |
333 | hvc_kick(); | |
334 | return 0; | |
335 | } /* else count == 0 */ | |
336 | ||
337 | tty->driver_data = hp; | |
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 LT |
473 | if (n <= 0) { |
474 | if (n == 0) | |
475 | return; | |
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 | ||
487 | static inline int __hvc_write_kernel(struct hvc_struct *hp, | |
488 | const unsigned char *buf, int count) | |
489 | { | |
490 | unsigned long flags; | |
491 | int rsize, written = 0; | |
492 | ||
493 | spin_lock_irqsave(&hp->lock, flags); | |
494 | ||
495 | /* Push pending writes */ | |
496 | if (hp->n_outbuf > 0) | |
497 | hvc_push(hp); | |
498 | ||
499 | while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { | |
500 | if (rsize > count) | |
501 | rsize = count; | |
502 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
503 | count -= rsize; | |
504 | buf += rsize; | |
505 | hp->n_outbuf += rsize; | |
506 | written += rsize; | |
507 | hvc_push(hp); | |
508 | } | |
509 | spin_unlock_irqrestore(&hp->lock, flags); | |
510 | ||
511 | return written; | |
512 | } | |
513 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
514 | { | |
515 | struct hvc_struct *hp = tty->driver_data; | |
516 | int written; | |
517 | ||
518 | /* This write was probably executed during a tty close. */ | |
519 | if (!hp) | |
520 | return -EPIPE; | |
521 | ||
522 | if (hp->count <= 0) | |
523 | return -EIO; | |
524 | ||
525 | written = __hvc_write_kernel(hp, buf, count); | |
526 | ||
527 | /* | |
528 | * Racy, but harmless, kick thread if there is still pending data. | |
529 | * There really is nothing wrong with kicking the thread, even if there | |
530 | * is no buffered data. | |
531 | */ | |
532 | if (hp->n_outbuf) | |
533 | hvc_kick(); | |
534 | ||
535 | return written; | |
536 | } | |
537 | ||
538 | /* | |
539 | * This is actually a contract between the driver and the tty layer outlining | |
540 | * how much write room the driver can guarentee will be sent OR BUFFERED. This | |
541 | * driver MUST honor the return value. | |
542 | */ | |
543 | static int hvc_write_room(struct tty_struct *tty) | |
544 | { | |
545 | struct hvc_struct *hp = tty->driver_data; | |
546 | ||
547 | if (!hp) | |
548 | return -1; | |
549 | ||
550 | return N_OUTBUF - hp->n_outbuf; | |
551 | } | |
552 | ||
553 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
554 | { | |
555 | struct hvc_struct *hp = tty->driver_data; | |
556 | ||
557 | if (!hp) | |
558 | return -1; | |
559 | return hp->n_outbuf; | |
560 | } | |
561 | ||
562 | #define HVC_POLL_READ 0x00000001 | |
563 | #define HVC_POLL_WRITE 0x00000002 | |
564 | #define HVC_POLL_QUICK 0x00000004 | |
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); | |
579 | /* Reschedule us if still some write pending */ | |
580 | if (hp->n_outbuf > 0) | |
581 | poll_mask |= HVC_POLL_WRITE; | |
582 | ||
583 | /* No tty attached, just skip */ | |
584 | tty = hp->tty; | |
585 | if (tty == NULL) | |
586 | goto bail; | |
587 | ||
588 | /* Now check if we can get data (are we throttled ?) */ | |
589 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
590 | goto throttled; | |
591 | ||
592 | /* If we aren't interrupt driven and aren't throttled, we always | |
593 | * request a reschedule | |
594 | */ | |
595 | if (hp->irq == NO_IRQ) | |
596 | poll_mask |= HVC_POLL_READ; | |
597 | ||
598 | /* Read data if any */ | |
599 | for (;;) { | |
33f0f88f | 600 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
601 | |
602 | /* If flip is full, just reschedule a later read */ | |
603 | if (count == 0) { | |
604 | poll_mask |= HVC_POLL_READ; | |
605 | break; | |
606 | } | |
607 | ||
030ffad2 | 608 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
609 | if (n <= 0) { |
610 | /* Hangup the tty when disconnected from host */ | |
611 | if (n == -EPIPE) { | |
612 | spin_unlock_irqrestore(&hp->lock, flags); | |
613 | tty_hangup(tty); | |
614 | spin_lock_irqsave(&hp->lock, flags); | |
615 | } | |
616 | break; | |
617 | } | |
618 | for (i = 0; i < n; ++i) { | |
619 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
620 | if (hp->index == hvc_con_driver.index) { |
621 | /* Handle the SysRq Hack */ | |
622 | /* XXX should support a sequence */ | |
623 | if (buf[i] == '\x0f') { /* ^O */ | |
624 | sysrq_pressed = 1; | |
625 | continue; | |
626 | } else if (sysrq_pressed) { | |
627 | handle_sysrq(buf[i], NULL, tty); | |
628 | sysrq_pressed = 0; | |
629 | continue; | |
630 | } | |
1da177e4 LT |
631 | } |
632 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
633 | tty_insert_flip_char(tty, buf[i], 0); | |
634 | } | |
635 | ||
33f0f88f | 636 | if (count) |
1da177e4 LT |
637 | tty_schedule_flip(tty); |
638 | ||
639 | /* | |
640 | * Account for the total amount read in one loop, and if above | |
8b67f8c1 MM |
641 | * 64 bytes, we do a quick schedule loop to let the tty grok |
642 | * the data and eventually throttle us. | |
1da177e4 LT |
643 | */ |
644 | read_total += n; | |
645 | if (read_total >= 64) { | |
646 | poll_mask |= HVC_POLL_QUICK; | |
647 | break; | |
648 | } | |
649 | } | |
650 | throttled: | |
651 | /* Wakeup write queue if necessary */ | |
652 | if (hp->do_wakeup) { | |
653 | hp->do_wakeup = 0; | |
654 | tty_wakeup(tty); | |
655 | } | |
656 | bail: | |
657 | spin_unlock_irqrestore(&hp->lock, flags); | |
658 | ||
659 | return poll_mask; | |
660 | } | |
661 | ||
662 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
663 | extern cpumask_t cpus_in_xmon; | |
664 | #else | |
665 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
666 | #endif | |
667 | ||
668 | /* | |
669 | * This kthread is either polling or interrupt driven. This is determined by | |
670 | * calling hvc_poll() who determines whether a console adapter support | |
671 | * interrupts. | |
672 | */ | |
673 | int khvcd(void *unused) | |
674 | { | |
675 | int poll_mask; | |
676 | struct hvc_struct *hp; | |
677 | ||
678 | __set_current_state(TASK_RUNNING); | |
679 | do { | |
680 | poll_mask = 0; | |
681 | hvc_kicked = 0; | |
682 | wmb(); | |
683 | if (cpus_empty(cpus_in_xmon)) { | |
684 | spin_lock(&hvc_structs_lock); | |
685 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
686 | poll_mask |= hvc_poll(hp); |
687 | } | |
688 | spin_unlock(&hvc_structs_lock); | |
689 | } else | |
690 | poll_mask |= HVC_POLL_READ; | |
691 | if (hvc_kicked) | |
692 | continue; | |
693 | if (poll_mask & HVC_POLL_QUICK) { | |
694 | yield(); | |
695 | continue; | |
696 | } | |
697 | set_current_state(TASK_INTERRUPTIBLE); | |
698 | if (!hvc_kicked) { | |
699 | if (poll_mask == 0) | |
700 | schedule(); | |
701 | else | |
702 | msleep_interruptible(TIMEOUT); | |
703 | } | |
704 | __set_current_state(TASK_RUNNING); | |
705 | } while (!kthread_should_stop()); | |
706 | ||
707 | return 0; | |
708 | } | |
709 | ||
710 | static struct tty_operations hvc_ops = { | |
711 | .open = hvc_open, | |
712 | .close = hvc_close, | |
713 | .write = hvc_write, | |
714 | .hangup = hvc_hangup, | |
715 | .unthrottle = hvc_unthrottle, | |
716 | .write_room = hvc_write_room, | |
717 | .chars_in_buffer = hvc_chars_in_buffer, | |
718 | }; | |
719 | ||
1da177e4 LT |
720 | /* callback when the kboject ref count reaches zero. */ |
721 | static void destroy_hvc_struct(struct kobject *kobj) | |
722 | { | |
723 | struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); | |
724 | unsigned long flags; | |
725 | ||
726 | spin_lock(&hvc_structs_lock); | |
727 | ||
728 | spin_lock_irqsave(&hp->lock, flags); | |
729 | list_del(&(hp->next)); | |
730 | spin_unlock_irqrestore(&hp->lock, flags); | |
731 | ||
732 | spin_unlock(&hvc_structs_lock); | |
733 | ||
734 | kfree(hp); | |
735 | } | |
736 | ||
737 | static struct kobj_type hvc_kobj_type = { | |
738 | .release = destroy_hvc_struct, | |
739 | }; | |
740 | ||
030ffad2 MM |
741 | struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, |
742 | struct hv_ops *ops) | |
1da177e4 LT |
743 | { |
744 | struct hvc_struct *hp; | |
6f24808e | 745 | int i; |
1da177e4 | 746 | |
1da177e4 LT |
747 | hp = kmalloc(sizeof(*hp), GFP_KERNEL); |
748 | if (!hp) | |
acad9559 | 749 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
750 | |
751 | memset(hp, 0x00, sizeof(*hp)); | |
acad9559 MM |
752 | |
753 | hp->vtermno = vtermno; | |
754 | hp->irq = irq; | |
030ffad2 | 755 | hp->ops = ops; |
1da177e4 LT |
756 | |
757 | kobject_init(&hp->kobj); | |
758 | hp->kobj.ktype = &hvc_kobj_type; | |
759 | ||
760 | spin_lock_init(&hp->lock); | |
761 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
762 | |
763 | /* | |
764 | * find index to use: | |
765 | * see if this vterm id matches one registered for console. | |
766 | */ | |
767 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
768 | if (vtermnos[i] == hp->vtermno) | |
769 | break; | |
770 | ||
771 | /* no matching slot, just use a counter */ | |
772 | if (i >= MAX_NR_HVC_CONSOLES) | |
773 | i = ++last_hvc; | |
774 | ||
775 | hp->index = i; | |
776 | ||
1da177e4 LT |
777 | list_add_tail(&(hp->next), &hvc_structs); |
778 | spin_unlock(&hvc_structs_lock); | |
779 | ||
acad9559 | 780 | return hp; |
1da177e4 | 781 | } |
acad9559 | 782 | EXPORT_SYMBOL(hvc_alloc); |
1da177e4 | 783 | |
acad9559 | 784 | int __devexit hvc_remove(struct hvc_struct *hp) |
1da177e4 | 785 | { |
1da177e4 LT |
786 | unsigned long flags; |
787 | struct kobject *kobjp; | |
788 | struct tty_struct *tty; | |
789 | ||
790 | spin_lock_irqsave(&hp->lock, flags); | |
791 | tty = hp->tty; | |
792 | kobjp = &hp->kobj; | |
793 | ||
794 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
795 | vtermnos[hp->index] = -1; | |
796 | ||
797 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
798 | ||
799 | spin_unlock_irqrestore(&hp->lock, flags); | |
800 | ||
801 | /* | |
802 | * We 'put' the instance that was grabbed when the kobject instance | |
803 | * was intialized using kobject_init(). Let the last holder of this | |
804 | * kobject cause it to be removed, which will probably be the tty_hangup | |
805 | * below. | |
806 | */ | |
807 | kobject_put(kobjp); | |
808 | ||
809 | /* | |
810 | * This function call will auto chain call hvc_hangup. The tty should | |
811 | * always be valid at this time unless a simultaneous tty close already | |
812 | * cleaned up the hvc_struct. | |
813 | */ | |
814 | if (tty) | |
815 | tty_hangup(tty); | |
816 | return 0; | |
817 | } | |
acad9559 | 818 | EXPORT_SYMBOL(hvc_remove); |
1da177e4 LT |
819 | |
820 | /* Driver initialization. Follow console initialization. This is where the TTY | |
821 | * interfaces start to become available. */ | |
822 | int __init hvc_init(void) | |
823 | { | |
5f6d9c07 | 824 | /* We need more than hvc_count adapters due to hotplug additions. */ |
1da177e4 | 825 | hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
1da177e4 LT |
826 | if (!hvc_driver) |
827 | return -ENOMEM; | |
828 | ||
829 | hvc_driver->owner = THIS_MODULE; | |
830 | hvc_driver->devfs_name = "hvc/"; | |
831 | hvc_driver->driver_name = "hvc"; | |
832 | hvc_driver->name = "hvc"; | |
833 | hvc_driver->major = HVC_MAJOR; | |
834 | hvc_driver->minor_start = HVC_MINOR; | |
835 | hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM; | |
836 | hvc_driver->init_termios = tty_std_termios; | |
837 | hvc_driver->flags = TTY_DRIVER_REAL_RAW; | |
838 | tty_set_operations(hvc_driver, &hvc_ops); | |
839 | ||
1da177e4 LT |
840 | /* Always start the kthread because there can be hotplug vty adapters |
841 | * added later. */ | |
842 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
843 | if (IS_ERR(hvc_task)) { | |
844 | panic("Couldn't create kthread for console.\n"); | |
845 | put_tty_driver(hvc_driver); | |
846 | return -EIO; | |
847 | } | |
848 | ||
ef4cbee0 AB |
849 | if (tty_register_driver(hvc_driver)) |
850 | panic("Couldn't register hvc console driver\n"); | |
851 | ||
acad9559 | 852 | return 0; |
1da177e4 | 853 | } |
837dcfaf | 854 | module_init(hvc_init); |
1da177e4 | 855 | |
320da0d2 MM |
856 | /* This isn't particularily necessary due to this being a console driver |
857 | * but it is nice to be thorough. | |
858 | */ | |
1da177e4 LT |
859 | static void __exit hvc_exit(void) |
860 | { | |
861 | kthread_stop(hvc_task); | |
862 | ||
1da177e4 LT |
863 | tty_unregister_driver(hvc_driver); |
864 | /* return tty_struct instances allocated in hvc_init(). */ | |
865 | put_tty_driver(hvc_driver); | |
320da0d2 | 866 | unregister_console(&hvc_con_driver); |
1da177e4 | 867 | } |
1da177e4 | 868 | module_exit(hvc_exit); |