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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> | |
44 | #include <asm/vio.h> | |
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 | /* | |
58 | * The Linux TTY code does not support dynamic addition of tty derived devices | |
59 | * so we need to know how many tty devices we might need when space is allocated | |
60 | * for the tty device. Since this driver supports hotplug of vty adapters we | |
61 | * need to make sure we have enough allocated. | |
62 | */ | |
63 | #define HVC_ALLOC_TTY_ADAPTERS 8 | |
64 | ||
1da177e4 LT |
65 | #define N_OUTBUF 16 |
66 | #define N_INBUF 16 | |
67 | ||
68 | #define __ALIGNED__ __attribute__((__aligned__(8))) | |
69 | ||
837dcfaf MM |
70 | static struct tty_driver *hvc_driver; |
71 | static struct task_struct *hvc_task; | |
72 | ||
73 | /* Picks up late kicks after list walk but before schedule() */ | |
74 | static int hvc_kicked; | |
75 | ||
76 | #ifdef CONFIG_MAGIC_SYSRQ | |
77 | static int sysrq_pressed; | |
78 | #endif | |
79 | ||
1da177e4 LT |
80 | struct hvc_struct { |
81 | spinlock_t lock; | |
82 | int index; | |
83 | struct tty_struct *tty; | |
84 | unsigned int count; | |
85 | int do_wakeup; | |
86 | char outbuf[N_OUTBUF] __ALIGNED__; | |
87 | int n_outbuf; | |
88 | uint32_t vtermno; | |
89 | int irq_requested; | |
90 | int irq; | |
91 | struct list_head next; | |
92 | struct kobject kobj; /* ref count & hvc_struct lifetime */ | |
93 | struct vio_dev *vdev; | |
94 | }; | |
95 | ||
96 | /* dynamic list of hvc_struct instances */ | |
97 | static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs); | |
98 | ||
99 | /* | |
100 | * Protect the list of hvc_struct instances from inserts and removals during | |
101 | * list traversal. | |
102 | */ | |
103 | static DEFINE_SPINLOCK(hvc_structs_lock); | |
104 | ||
837dcfaf | 105 | /* |
6f24808e MM |
106 | * This value is used to assign a tty->index value to a hvc_struct based |
107 | * upon order of exposure via hvc_probe(), when we can not match it to | |
108 | * a console canidate registered with hvc_instantiate(). | |
837dcfaf | 109 | */ |
6f24808e | 110 | static int last_hvc = -1; |
837dcfaf MM |
111 | |
112 | /* | |
113 | * Do not call this function with either the hvc_strucst_lock or the hvc_struct | |
114 | * lock held. If successful, this function increments the kobject reference | |
115 | * count against the target hvc_struct so it should be released when finished. | |
116 | */ | |
117 | struct hvc_struct *hvc_get_by_index(int index) | |
118 | { | |
119 | struct hvc_struct *hp; | |
120 | unsigned long flags; | |
121 | ||
122 | spin_lock(&hvc_structs_lock); | |
123 | ||
124 | list_for_each_entry(hp, &hvc_structs, next) { | |
125 | spin_lock_irqsave(&hp->lock, flags); | |
126 | if (hp->index == index) { | |
127 | kobject_get(&hp->kobj); | |
128 | spin_unlock_irqrestore(&hp->lock, flags); | |
129 | spin_unlock(&hvc_structs_lock); | |
130 | return hp; | |
131 | } | |
132 | spin_unlock_irqrestore(&hp->lock, flags); | |
133 | } | |
134 | hp = NULL; | |
135 | ||
136 | spin_unlock(&hvc_structs_lock); | |
137 | return hp; | |
138 | } | |
139 | ||
140 | ||
1da177e4 LT |
141 | /* |
142 | * Initial console vtermnos for console API usage prior to full console | |
143 | * initialization. Any vty adapter outside this range will not have usable | |
144 | * console interfaces but can still be used as a tty device. This has to be | |
145 | * static because kmalloc will not work during early console init. | |
146 | */ | |
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; | |
159 | int r, donecr = 0; | |
160 | ||
161 | /* Console access attempt outside of acceptable console range. */ | |
162 | if (co->index >= MAX_NR_HVC_CONSOLES) | |
163 | return; | |
164 | ||
165 | /* This console adapter was removed so it is not useable. */ | |
166 | if (vtermnos[co->index] < 0) | |
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 { | |
180 | r = hvc_put_chars(vtermnos[co->index], c, i); | |
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 | */ |
837dcfaf MM |
250 | int hvc_instantiate(uint32_t vtermno, int index) |
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; |
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 | } | |
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; | |
336 | hp->tty = tty; | |
337 | /* Save for request_irq outside of spin_lock. */ | |
338 | irq = hp->irq; | |
339 | if (irq != NO_IRQ) | |
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 */ | |
346 | if (irq != NO_IRQ) | |
347 | rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp); | |
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; | |
374 | int irq = NO_IRQ; | |
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 | ||
408 | if (irq != NO_IRQ) | |
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; | |
425 | int irq = NO_IRQ; | |
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); | |
454 | if (irq != NO_IRQ) | |
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 | ||
470 | n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); | |
471 | if (n <= 0) { | |
472 | if (n == 0) | |
473 | return; | |
474 | /* throw away output on error; this happens when | |
475 | there is no session connected to the vterm. */ | |
476 | hp->n_outbuf = 0; | |
477 | } else | |
478 | hp->n_outbuf -= n; | |
479 | if (hp->n_outbuf > 0) | |
480 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
481 | else | |
482 | hp->do_wakeup = 1; | |
483 | } | |
484 | ||
485 | static inline int __hvc_write_kernel(struct hvc_struct *hp, | |
486 | const unsigned char *buf, int count) | |
487 | { | |
488 | unsigned long flags; | |
489 | int rsize, written = 0; | |
490 | ||
491 | spin_lock_irqsave(&hp->lock, flags); | |
492 | ||
493 | /* Push pending writes */ | |
494 | if (hp->n_outbuf > 0) | |
495 | hvc_push(hp); | |
496 | ||
497 | while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { | |
498 | if (rsize > count) | |
499 | rsize = count; | |
500 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
501 | count -= rsize; | |
502 | buf += rsize; | |
503 | hp->n_outbuf += rsize; | |
504 | written += rsize; | |
505 | hvc_push(hp); | |
506 | } | |
507 | spin_unlock_irqrestore(&hp->lock, flags); | |
508 | ||
509 | return written; | |
510 | } | |
511 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
512 | { | |
513 | struct hvc_struct *hp = tty->driver_data; | |
514 | int written; | |
515 | ||
516 | /* This write was probably executed during a tty close. */ | |
517 | if (!hp) | |
518 | return -EPIPE; | |
519 | ||
520 | if (hp->count <= 0) | |
521 | return -EIO; | |
522 | ||
523 | written = __hvc_write_kernel(hp, buf, count); | |
524 | ||
525 | /* | |
526 | * Racy, but harmless, kick thread if there is still pending data. | |
527 | * There really is nothing wrong with kicking the thread, even if there | |
528 | * is no buffered data. | |
529 | */ | |
530 | if (hp->n_outbuf) | |
531 | hvc_kick(); | |
532 | ||
533 | return written; | |
534 | } | |
535 | ||
536 | /* | |
537 | * This is actually a contract between the driver and the tty layer outlining | |
538 | * how much write room the driver can guarentee will be sent OR BUFFERED. This | |
539 | * driver MUST honor the return value. | |
540 | */ | |
541 | static int hvc_write_room(struct tty_struct *tty) | |
542 | { | |
543 | struct hvc_struct *hp = tty->driver_data; | |
544 | ||
545 | if (!hp) | |
546 | return -1; | |
547 | ||
548 | return N_OUTBUF - hp->n_outbuf; | |
549 | } | |
550 | ||
551 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
552 | { | |
553 | struct hvc_struct *hp = tty->driver_data; | |
554 | ||
555 | if (!hp) | |
556 | return -1; | |
557 | return hp->n_outbuf; | |
558 | } | |
559 | ||
560 | #define HVC_POLL_READ 0x00000001 | |
561 | #define HVC_POLL_WRITE 0x00000002 | |
562 | #define HVC_POLL_QUICK 0x00000004 | |
563 | ||
564 | static int hvc_poll(struct hvc_struct *hp) | |
565 | { | |
566 | struct tty_struct *tty; | |
567 | int i, n, poll_mask = 0; | |
568 | char buf[N_INBUF] __ALIGNED__; | |
569 | unsigned long flags; | |
570 | int read_total = 0; | |
571 | ||
572 | spin_lock_irqsave(&hp->lock, flags); | |
573 | ||
574 | /* Push pending writes */ | |
575 | if (hp->n_outbuf > 0) | |
576 | hvc_push(hp); | |
577 | /* Reschedule us if still some write pending */ | |
578 | if (hp->n_outbuf > 0) | |
579 | poll_mask |= HVC_POLL_WRITE; | |
580 | ||
581 | /* No tty attached, just skip */ | |
582 | tty = hp->tty; | |
583 | if (tty == NULL) | |
584 | goto bail; | |
585 | ||
586 | /* Now check if we can get data (are we throttled ?) */ | |
587 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
588 | goto throttled; | |
589 | ||
590 | /* If we aren't interrupt driven and aren't throttled, we always | |
591 | * request a reschedule | |
592 | */ | |
593 | if (hp->irq == NO_IRQ) | |
594 | poll_mask |= HVC_POLL_READ; | |
595 | ||
596 | /* Read data if any */ | |
597 | for (;;) { | |
598 | int count = N_INBUF; | |
599 | if (count > (TTY_FLIPBUF_SIZE - tty->flip.count)) | |
600 | count = TTY_FLIPBUF_SIZE - tty->flip.count; | |
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 | ||
608 | n = hvc_get_chars(hp->vtermno, buf, count); | |
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 | ||
636 | if (tty->flip.count) | |
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 | ||
741 | static int __devinit hvc_probe( | |
742 | struct vio_dev *dev, | |
743 | const struct vio_device_id *id) | |
744 | { | |
745 | struct hvc_struct *hp; | |
6f24808e | 746 | int i; |
1da177e4 LT |
747 | |
748 | /* probed with invalid parameters. */ | |
749 | if (!dev || !id) | |
750 | return -EPERM; | |
751 | ||
752 | hp = kmalloc(sizeof(*hp), GFP_KERNEL); | |
753 | if (!hp) | |
754 | return -ENOMEM; | |
755 | ||
756 | memset(hp, 0x00, sizeof(*hp)); | |
757 | hp->vtermno = dev->unit_address; | |
758 | hp->vdev = dev; | |
759 | hp->vdev->dev.driver_data = hp; | |
760 | hp->irq = dev->irq; | |
761 | ||
762 | kobject_init(&hp->kobj); | |
763 | hp->kobj.ktype = &hvc_kobj_type; | |
764 | ||
765 | spin_lock_init(&hp->lock); | |
766 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
767 | |
768 | /* | |
769 | * find index to use: | |
770 | * see if this vterm id matches one registered for console. | |
771 | */ | |
772 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
773 | if (vtermnos[i] == hp->vtermno) | |
774 | break; | |
775 | ||
776 | /* no matching slot, just use a counter */ | |
777 | if (i >= MAX_NR_HVC_CONSOLES) | |
778 | i = ++last_hvc; | |
779 | ||
780 | hp->index = i; | |
781 | ||
1da177e4 LT |
782 | list_add_tail(&(hp->next), &hvc_structs); |
783 | spin_unlock(&hvc_structs_lock); | |
784 | ||
785 | return 0; | |
786 | } | |
787 | ||
788 | static int __devexit hvc_remove(struct vio_dev *dev) | |
789 | { | |
790 | struct hvc_struct *hp = dev->dev.driver_data; | |
791 | unsigned long flags; | |
792 | struct kobject *kobjp; | |
793 | struct tty_struct *tty; | |
794 | ||
795 | spin_lock_irqsave(&hp->lock, flags); | |
796 | tty = hp->tty; | |
797 | kobjp = &hp->kobj; | |
798 | ||
799 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
800 | vtermnos[hp->index] = -1; | |
801 | ||
802 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
803 | ||
804 | spin_unlock_irqrestore(&hp->lock, flags); | |
805 | ||
806 | /* | |
807 | * We 'put' the instance that was grabbed when the kobject instance | |
808 | * was intialized using kobject_init(). Let the last holder of this | |
809 | * kobject cause it to be removed, which will probably be the tty_hangup | |
810 | * below. | |
811 | */ | |
812 | kobject_put(kobjp); | |
813 | ||
814 | /* | |
815 | * This function call will auto chain call hvc_hangup. The tty should | |
816 | * always be valid at this time unless a simultaneous tty close already | |
817 | * cleaned up the hvc_struct. | |
818 | */ | |
819 | if (tty) | |
820 | tty_hangup(tty); | |
821 | return 0; | |
822 | } | |
823 | ||
837dcfaf MM |
824 | char hvc_driver_name[] = "hvc_console"; |
825 | ||
826 | static struct vio_device_id hvc_driver_table[] __devinitdata= { | |
827 | {"serial", "hvterm1"}, | |
828 | { NULL, } | |
829 | }; | |
830 | MODULE_DEVICE_TABLE(vio, hvc_driver_table); | |
831 | ||
1da177e4 LT |
832 | static struct vio_driver hvc_vio_driver = { |
833 | .name = hvc_driver_name, | |
834 | .id_table = hvc_driver_table, | |
835 | .probe = hvc_probe, | |
836 | .remove = hvc_remove, | |
837 | }; | |
838 | ||
839 | /* Driver initialization. Follow console initialization. This is where the TTY | |
840 | * interfaces start to become available. */ | |
841 | int __init hvc_init(void) | |
842 | { | |
843 | int rc; | |
844 | ||
5f6d9c07 | 845 | /* We need more than hvc_count adapters due to hotplug additions. */ |
1da177e4 | 846 | hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
1da177e4 LT |
847 | if (!hvc_driver) |
848 | return -ENOMEM; | |
849 | ||
850 | hvc_driver->owner = THIS_MODULE; | |
851 | hvc_driver->devfs_name = "hvc/"; | |
852 | hvc_driver->driver_name = "hvc"; | |
853 | hvc_driver->name = "hvc"; | |
854 | hvc_driver->major = HVC_MAJOR; | |
855 | hvc_driver->minor_start = HVC_MINOR; | |
856 | hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM; | |
857 | hvc_driver->init_termios = tty_std_termios; | |
858 | hvc_driver->flags = TTY_DRIVER_REAL_RAW; | |
859 | tty_set_operations(hvc_driver, &hvc_ops); | |
860 | ||
861 | if (tty_register_driver(hvc_driver)) | |
862 | panic("Couldn't register hvc console driver\n"); | |
863 | ||
864 | /* Always start the kthread because there can be hotplug vty adapters | |
865 | * added later. */ | |
866 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
867 | if (IS_ERR(hvc_task)) { | |
868 | panic("Couldn't create kthread for console.\n"); | |
869 | put_tty_driver(hvc_driver); | |
870 | return -EIO; | |
871 | } | |
872 | ||
873 | /* Register as a vio device to receive callbacks */ | |
874 | rc = vio_register_driver(&hvc_vio_driver); | |
875 | ||
876 | return rc; | |
877 | } | |
837dcfaf | 878 | module_init(hvc_init); |
1da177e4 | 879 | |
320da0d2 MM |
880 | /* This isn't particularily necessary due to this being a console driver |
881 | * but it is nice to be thorough. | |
882 | */ | |
1da177e4 LT |
883 | static void __exit hvc_exit(void) |
884 | { | |
885 | kthread_stop(hvc_task); | |
886 | ||
887 | vio_unregister_driver(&hvc_vio_driver); | |
888 | tty_unregister_driver(hvc_driver); | |
889 | /* return tty_struct instances allocated in hvc_init(). */ | |
890 | put_tty_driver(hvc_driver); | |
320da0d2 | 891 | unregister_console(&hvc_con_driver); |
1da177e4 | 892 | } |
1da177e4 | 893 | module_exit(hvc_exit); |