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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 | */ | |
147 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES]; | |
148 | ||
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 | { | |
195 | *index = c->index; | |
196 | return hvc_driver; | |
197 | } | |
198 | ||
199 | static int __init hvc_console_setup(struct console *co, char *options) | |
200 | { | |
201 | return 0; | |
202 | } | |
203 | ||
204 | struct console hvc_con_driver = { | |
205 | .name = "hvc", | |
206 | .write = hvc_console_print, | |
207 | .device = hvc_console_device, | |
208 | .setup = hvc_console_setup, | |
209 | .flags = CON_PRINTBUFFER, | |
210 | .index = -1, | |
211 | }; | |
212 | ||
213 | /* Early console initialization. Preceeds driver initialization. */ | |
214 | static int __init hvc_console_init(void) | |
215 | { | |
216 | int i; | |
217 | ||
218 | for (i=0; i<MAX_NR_HVC_CONSOLES; i++) | |
219 | vtermnos[i] = -1; | |
5f6d9c07 | 220 | hvc_find_vtys(); |
837dcfaf MM |
221 | register_console(&hvc_con_driver); |
222 | return 0; | |
223 | } | |
224 | console_initcall(hvc_console_init); | |
1da177e4 LT |
225 | |
226 | /* | |
6f24808e MM |
227 | * hvc_instantiate() is an early console discovery method which locates |
228 | * consoles * prior to the vio subsystem discovering them. Hotplugged | |
229 | * vty adapters do NOT get an hvc_instantiate() callback since they | |
230 | * appear after early console init. | |
1da177e4 | 231 | */ |
837dcfaf MM |
232 | int hvc_instantiate(uint32_t vtermno, int index) |
233 | { | |
234 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) | |
235 | return -1; | |
1da177e4 | 236 | |
837dcfaf MM |
237 | if (vtermnos[index] != -1) |
238 | return -1; | |
239 | ||
240 | vtermnos[index] = vtermno; | |
6f24808e MM |
241 | |
242 | /* reserve all indices upto and including this index */ | |
243 | if (last_hvc < index) | |
244 | last_hvc = index; | |
245 | ||
837dcfaf MM |
246 | return 0; |
247 | } | |
1da177e4 LT |
248 | |
249 | /* Wake the sleeping khvcd */ | |
250 | static void hvc_kick(void) | |
251 | { | |
252 | hvc_kicked = 1; | |
253 | wake_up_process(hvc_task); | |
254 | } | |
255 | ||
8b67f8c1 MM |
256 | static int hvc_poll(struct hvc_struct *hp); |
257 | ||
1da177e4 LT |
258 | /* |
259 | * NOTE: This API isn't used if the console adapter doesn't support interrupts. | |
260 | * In this case the console is poll driven. | |
261 | */ | |
262 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs) | |
263 | { | |
8b67f8c1 MM |
264 | /* if hvc_poll request a repoll, then kick the hvcd thread */ |
265 | if (hvc_poll(dev_instance)) | |
266 | hvc_kick(); | |
1da177e4 LT |
267 | return IRQ_HANDLED; |
268 | } | |
269 | ||
270 | static void hvc_unthrottle(struct tty_struct *tty) | |
271 | { | |
272 | hvc_kick(); | |
273 | } | |
274 | ||
1da177e4 LT |
275 | /* |
276 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
277 | * adapter to the kernel. | |
278 | */ | |
279 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
280 | { | |
281 | struct hvc_struct *hp; | |
282 | unsigned long flags; | |
283 | int irq = NO_IRQ; | |
284 | int rc = 0; | |
285 | struct kobject *kobjp; | |
286 | ||
287 | /* Auto increments kobject reference if found. */ | |
288 | if (!(hp = hvc_get_by_index(tty->index))) { | |
289 | printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n"); | |
290 | return -ENODEV; | |
291 | } | |
292 | ||
293 | spin_lock_irqsave(&hp->lock, flags); | |
294 | /* Check and then increment for fast path open. */ | |
295 | if (hp->count++ > 0) { | |
296 | spin_unlock_irqrestore(&hp->lock, flags); | |
297 | hvc_kick(); | |
298 | return 0; | |
299 | } /* else count == 0 */ | |
300 | ||
301 | tty->driver_data = hp; | |
302 | hp->tty = tty; | |
303 | /* Save for request_irq outside of spin_lock. */ | |
304 | irq = hp->irq; | |
305 | if (irq != NO_IRQ) | |
306 | hp->irq_requested = 1; | |
307 | ||
308 | kobjp = &hp->kobj; | |
309 | ||
310 | spin_unlock_irqrestore(&hp->lock, flags); | |
311 | /* check error, fallback to non-irq */ | |
312 | if (irq != NO_IRQ) | |
313 | rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp); | |
314 | ||
315 | /* | |
316 | * If the request_irq() fails and we return an error. The tty layer | |
317 | * will call hvc_close() after a failed open but we don't want to clean | |
318 | * up there so we'll clean up here and clear out the previously set | |
319 | * tty fields and return the kobject reference. | |
320 | */ | |
321 | if (rc) { | |
322 | spin_lock_irqsave(&hp->lock, flags); | |
323 | hp->tty = NULL; | |
324 | hp->irq_requested = 0; | |
325 | spin_unlock_irqrestore(&hp->lock, flags); | |
326 | tty->driver_data = NULL; | |
327 | kobject_put(kobjp); | |
328 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); | |
329 | } | |
330 | /* Force wakeup of the polling thread */ | |
331 | hvc_kick(); | |
332 | ||
333 | return rc; | |
334 | } | |
335 | ||
336 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
337 | { | |
338 | struct hvc_struct *hp; | |
339 | struct kobject *kobjp; | |
340 | int irq = NO_IRQ; | |
341 | unsigned long flags; | |
342 | ||
343 | if (tty_hung_up_p(filp)) | |
344 | return; | |
345 | ||
346 | /* | |
347 | * No driver_data means that this close was issued after a failed | |
348 | * hvc_open by the tty layer's release_dev() function and we can just | |
349 | * exit cleanly because the kobject reference wasn't made. | |
350 | */ | |
351 | if (!tty->driver_data) | |
352 | return; | |
353 | ||
354 | hp = tty->driver_data; | |
355 | spin_lock_irqsave(&hp->lock, flags); | |
356 | ||
357 | kobjp = &hp->kobj; | |
358 | if (--hp->count == 0) { | |
359 | if (hp->irq_requested) | |
360 | irq = hp->irq; | |
361 | hp->irq_requested = 0; | |
362 | ||
363 | /* We are done with the tty pointer now. */ | |
364 | hp->tty = NULL; | |
365 | spin_unlock_irqrestore(&hp->lock, flags); | |
366 | ||
367 | /* | |
368 | * Chain calls chars_in_buffer() and returns immediately if | |
369 | * there is no buffered data otherwise sleeps on a wait queue | |
370 | * waking periodically to check chars_in_buffer(). | |
371 | */ | |
372 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
373 | ||
374 | if (irq != NO_IRQ) | |
375 | free_irq(irq, hp); | |
376 | ||
377 | } else { | |
378 | if (hp->count < 0) | |
379 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
380 | hp->vtermno, hp->count); | |
381 | spin_unlock_irqrestore(&hp->lock, flags); | |
382 | } | |
383 | ||
384 | kobject_put(kobjp); | |
385 | } | |
386 | ||
387 | static void hvc_hangup(struct tty_struct *tty) | |
388 | { | |
389 | struct hvc_struct *hp = tty->driver_data; | |
390 | unsigned long flags; | |
391 | int irq = NO_IRQ; | |
392 | int temp_open_count; | |
393 | struct kobject *kobjp; | |
394 | ||
395 | if (!hp) | |
396 | return; | |
397 | ||
398 | spin_lock_irqsave(&hp->lock, flags); | |
399 | ||
400 | /* | |
401 | * The N_TTY line discipline has problems such that in a close vs | |
402 | * open->hangup case this can be called after the final close so prevent | |
403 | * that from happening for now. | |
404 | */ | |
405 | if (hp->count <= 0) { | |
406 | spin_unlock_irqrestore(&hp->lock, flags); | |
407 | return; | |
408 | } | |
409 | ||
410 | kobjp = &hp->kobj; | |
411 | temp_open_count = hp->count; | |
412 | hp->count = 0; | |
413 | hp->n_outbuf = 0; | |
414 | hp->tty = NULL; | |
415 | if (hp->irq_requested) | |
416 | /* Saved for use outside of spin_lock. */ | |
417 | irq = hp->irq; | |
418 | hp->irq_requested = 0; | |
419 | spin_unlock_irqrestore(&hp->lock, flags); | |
420 | if (irq != NO_IRQ) | |
421 | free_irq(irq, hp); | |
422 | while(temp_open_count) { | |
423 | --temp_open_count; | |
424 | kobject_put(kobjp); | |
425 | } | |
426 | } | |
427 | ||
428 | /* | |
429 | * Push buffered characters whether they were just recently buffered or waiting | |
430 | * on a blocked hypervisor. Call this function with hp->lock held. | |
431 | */ | |
432 | static void hvc_push(struct hvc_struct *hp) | |
433 | { | |
434 | int n; | |
435 | ||
436 | n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); | |
437 | if (n <= 0) { | |
438 | if (n == 0) | |
439 | return; | |
440 | /* throw away output on error; this happens when | |
441 | there is no session connected to the vterm. */ | |
442 | hp->n_outbuf = 0; | |
443 | } else | |
444 | hp->n_outbuf -= n; | |
445 | if (hp->n_outbuf > 0) | |
446 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
447 | else | |
448 | hp->do_wakeup = 1; | |
449 | } | |
450 | ||
451 | static inline int __hvc_write_kernel(struct hvc_struct *hp, | |
452 | const unsigned char *buf, int count) | |
453 | { | |
454 | unsigned long flags; | |
455 | int rsize, written = 0; | |
456 | ||
457 | spin_lock_irqsave(&hp->lock, flags); | |
458 | ||
459 | /* Push pending writes */ | |
460 | if (hp->n_outbuf > 0) | |
461 | hvc_push(hp); | |
462 | ||
463 | while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { | |
464 | if (rsize > count) | |
465 | rsize = count; | |
466 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
467 | count -= rsize; | |
468 | buf += rsize; | |
469 | hp->n_outbuf += rsize; | |
470 | written += rsize; | |
471 | hvc_push(hp); | |
472 | } | |
473 | spin_unlock_irqrestore(&hp->lock, flags); | |
474 | ||
475 | return written; | |
476 | } | |
477 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
478 | { | |
479 | struct hvc_struct *hp = tty->driver_data; | |
480 | int written; | |
481 | ||
482 | /* This write was probably executed during a tty close. */ | |
483 | if (!hp) | |
484 | return -EPIPE; | |
485 | ||
486 | if (hp->count <= 0) | |
487 | return -EIO; | |
488 | ||
489 | written = __hvc_write_kernel(hp, buf, count); | |
490 | ||
491 | /* | |
492 | * Racy, but harmless, kick thread if there is still pending data. | |
493 | * There really is nothing wrong with kicking the thread, even if there | |
494 | * is no buffered data. | |
495 | */ | |
496 | if (hp->n_outbuf) | |
497 | hvc_kick(); | |
498 | ||
499 | return written; | |
500 | } | |
501 | ||
502 | /* | |
503 | * This is actually a contract between the driver and the tty layer outlining | |
504 | * how much write room the driver can guarentee will be sent OR BUFFERED. This | |
505 | * driver MUST honor the return value. | |
506 | */ | |
507 | static int hvc_write_room(struct tty_struct *tty) | |
508 | { | |
509 | struct hvc_struct *hp = tty->driver_data; | |
510 | ||
511 | if (!hp) | |
512 | return -1; | |
513 | ||
514 | return N_OUTBUF - hp->n_outbuf; | |
515 | } | |
516 | ||
517 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
518 | { | |
519 | struct hvc_struct *hp = tty->driver_data; | |
520 | ||
521 | if (!hp) | |
522 | return -1; | |
523 | return hp->n_outbuf; | |
524 | } | |
525 | ||
526 | #define HVC_POLL_READ 0x00000001 | |
527 | #define HVC_POLL_WRITE 0x00000002 | |
528 | #define HVC_POLL_QUICK 0x00000004 | |
529 | ||
530 | static int hvc_poll(struct hvc_struct *hp) | |
531 | { | |
532 | struct tty_struct *tty; | |
533 | int i, n, poll_mask = 0; | |
534 | char buf[N_INBUF] __ALIGNED__; | |
535 | unsigned long flags; | |
536 | int read_total = 0; | |
537 | ||
538 | spin_lock_irqsave(&hp->lock, flags); | |
539 | ||
540 | /* Push pending writes */ | |
541 | if (hp->n_outbuf > 0) | |
542 | hvc_push(hp); | |
543 | /* Reschedule us if still some write pending */ | |
544 | if (hp->n_outbuf > 0) | |
545 | poll_mask |= HVC_POLL_WRITE; | |
546 | ||
547 | /* No tty attached, just skip */ | |
548 | tty = hp->tty; | |
549 | if (tty == NULL) | |
550 | goto bail; | |
551 | ||
552 | /* Now check if we can get data (are we throttled ?) */ | |
553 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
554 | goto throttled; | |
555 | ||
556 | /* If we aren't interrupt driven and aren't throttled, we always | |
557 | * request a reschedule | |
558 | */ | |
559 | if (hp->irq == NO_IRQ) | |
560 | poll_mask |= HVC_POLL_READ; | |
561 | ||
562 | /* Read data if any */ | |
563 | for (;;) { | |
564 | int count = N_INBUF; | |
565 | if (count > (TTY_FLIPBUF_SIZE - tty->flip.count)) | |
566 | count = TTY_FLIPBUF_SIZE - tty->flip.count; | |
567 | ||
568 | /* If flip is full, just reschedule a later read */ | |
569 | if (count == 0) { | |
570 | poll_mask |= HVC_POLL_READ; | |
571 | break; | |
572 | } | |
573 | ||
574 | n = hvc_get_chars(hp->vtermno, buf, count); | |
575 | if (n <= 0) { | |
576 | /* Hangup the tty when disconnected from host */ | |
577 | if (n == -EPIPE) { | |
578 | spin_unlock_irqrestore(&hp->lock, flags); | |
579 | tty_hangup(tty); | |
580 | spin_lock_irqsave(&hp->lock, flags); | |
581 | } | |
582 | break; | |
583 | } | |
584 | for (i = 0; i < n; ++i) { | |
585 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
586 | if (hp->index == hvc_con_driver.index) { |
587 | /* Handle the SysRq Hack */ | |
588 | /* XXX should support a sequence */ | |
589 | if (buf[i] == '\x0f') { /* ^O */ | |
590 | sysrq_pressed = 1; | |
591 | continue; | |
592 | } else if (sysrq_pressed) { | |
593 | handle_sysrq(buf[i], NULL, tty); | |
594 | sysrq_pressed = 0; | |
595 | continue; | |
596 | } | |
1da177e4 LT |
597 | } |
598 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
599 | tty_insert_flip_char(tty, buf[i], 0); | |
600 | } | |
601 | ||
602 | if (tty->flip.count) | |
603 | tty_schedule_flip(tty); | |
604 | ||
605 | /* | |
606 | * Account for the total amount read in one loop, and if above | |
8b67f8c1 MM |
607 | * 64 bytes, we do a quick schedule loop to let the tty grok |
608 | * the data and eventually throttle us. | |
1da177e4 LT |
609 | */ |
610 | read_total += n; | |
611 | if (read_total >= 64) { | |
612 | poll_mask |= HVC_POLL_QUICK; | |
613 | break; | |
614 | } | |
615 | } | |
616 | throttled: | |
617 | /* Wakeup write queue if necessary */ | |
618 | if (hp->do_wakeup) { | |
619 | hp->do_wakeup = 0; | |
620 | tty_wakeup(tty); | |
621 | } | |
622 | bail: | |
623 | spin_unlock_irqrestore(&hp->lock, flags); | |
624 | ||
625 | return poll_mask; | |
626 | } | |
627 | ||
628 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
629 | extern cpumask_t cpus_in_xmon; | |
630 | #else | |
631 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
632 | #endif | |
633 | ||
634 | /* | |
635 | * This kthread is either polling or interrupt driven. This is determined by | |
636 | * calling hvc_poll() who determines whether a console adapter support | |
637 | * interrupts. | |
638 | */ | |
639 | int khvcd(void *unused) | |
640 | { | |
641 | int poll_mask; | |
642 | struct hvc_struct *hp; | |
643 | ||
644 | __set_current_state(TASK_RUNNING); | |
645 | do { | |
646 | poll_mask = 0; | |
647 | hvc_kicked = 0; | |
648 | wmb(); | |
649 | if (cpus_empty(cpus_in_xmon)) { | |
650 | spin_lock(&hvc_structs_lock); | |
651 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
652 | poll_mask |= hvc_poll(hp); |
653 | } | |
654 | spin_unlock(&hvc_structs_lock); | |
655 | } else | |
656 | poll_mask |= HVC_POLL_READ; | |
657 | if (hvc_kicked) | |
658 | continue; | |
659 | if (poll_mask & HVC_POLL_QUICK) { | |
660 | yield(); | |
661 | continue; | |
662 | } | |
663 | set_current_state(TASK_INTERRUPTIBLE); | |
664 | if (!hvc_kicked) { | |
665 | if (poll_mask == 0) | |
666 | schedule(); | |
667 | else | |
668 | msleep_interruptible(TIMEOUT); | |
669 | } | |
670 | __set_current_state(TASK_RUNNING); | |
671 | } while (!kthread_should_stop()); | |
672 | ||
673 | return 0; | |
674 | } | |
675 | ||
676 | static struct tty_operations hvc_ops = { | |
677 | .open = hvc_open, | |
678 | .close = hvc_close, | |
679 | .write = hvc_write, | |
680 | .hangup = hvc_hangup, | |
681 | .unthrottle = hvc_unthrottle, | |
682 | .write_room = hvc_write_room, | |
683 | .chars_in_buffer = hvc_chars_in_buffer, | |
684 | }; | |
685 | ||
1da177e4 LT |
686 | /* callback when the kboject ref count reaches zero. */ |
687 | static void destroy_hvc_struct(struct kobject *kobj) | |
688 | { | |
689 | struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); | |
690 | unsigned long flags; | |
691 | ||
692 | spin_lock(&hvc_structs_lock); | |
693 | ||
694 | spin_lock_irqsave(&hp->lock, flags); | |
695 | list_del(&(hp->next)); | |
696 | spin_unlock_irqrestore(&hp->lock, flags); | |
697 | ||
698 | spin_unlock(&hvc_structs_lock); | |
699 | ||
700 | kfree(hp); | |
701 | } | |
702 | ||
703 | static struct kobj_type hvc_kobj_type = { | |
704 | .release = destroy_hvc_struct, | |
705 | }; | |
706 | ||
707 | static int __devinit hvc_probe( | |
708 | struct vio_dev *dev, | |
709 | const struct vio_device_id *id) | |
710 | { | |
711 | struct hvc_struct *hp; | |
6f24808e | 712 | int i; |
1da177e4 LT |
713 | |
714 | /* probed with invalid parameters. */ | |
715 | if (!dev || !id) | |
716 | return -EPERM; | |
717 | ||
718 | hp = kmalloc(sizeof(*hp), GFP_KERNEL); | |
719 | if (!hp) | |
720 | return -ENOMEM; | |
721 | ||
722 | memset(hp, 0x00, sizeof(*hp)); | |
723 | hp->vtermno = dev->unit_address; | |
724 | hp->vdev = dev; | |
725 | hp->vdev->dev.driver_data = hp; | |
726 | hp->irq = dev->irq; | |
727 | ||
728 | kobject_init(&hp->kobj); | |
729 | hp->kobj.ktype = &hvc_kobj_type; | |
730 | ||
731 | spin_lock_init(&hp->lock); | |
732 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
733 | |
734 | /* | |
735 | * find index to use: | |
736 | * see if this vterm id matches one registered for console. | |
737 | */ | |
738 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
739 | if (vtermnos[i] == hp->vtermno) | |
740 | break; | |
741 | ||
742 | /* no matching slot, just use a counter */ | |
743 | if (i >= MAX_NR_HVC_CONSOLES) | |
744 | i = ++last_hvc; | |
745 | ||
746 | hp->index = i; | |
747 | ||
1da177e4 LT |
748 | list_add_tail(&(hp->next), &hvc_structs); |
749 | spin_unlock(&hvc_structs_lock); | |
750 | ||
751 | return 0; | |
752 | } | |
753 | ||
754 | static int __devexit hvc_remove(struct vio_dev *dev) | |
755 | { | |
756 | struct hvc_struct *hp = dev->dev.driver_data; | |
757 | unsigned long flags; | |
758 | struct kobject *kobjp; | |
759 | struct tty_struct *tty; | |
760 | ||
761 | spin_lock_irqsave(&hp->lock, flags); | |
762 | tty = hp->tty; | |
763 | kobjp = &hp->kobj; | |
764 | ||
765 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
766 | vtermnos[hp->index] = -1; | |
767 | ||
768 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
769 | ||
770 | spin_unlock_irqrestore(&hp->lock, flags); | |
771 | ||
772 | /* | |
773 | * We 'put' the instance that was grabbed when the kobject instance | |
774 | * was intialized using kobject_init(). Let the last holder of this | |
775 | * kobject cause it to be removed, which will probably be the tty_hangup | |
776 | * below. | |
777 | */ | |
778 | kobject_put(kobjp); | |
779 | ||
780 | /* | |
781 | * This function call will auto chain call hvc_hangup. The tty should | |
782 | * always be valid at this time unless a simultaneous tty close already | |
783 | * cleaned up the hvc_struct. | |
784 | */ | |
785 | if (tty) | |
786 | tty_hangup(tty); | |
787 | return 0; | |
788 | } | |
789 | ||
837dcfaf MM |
790 | char hvc_driver_name[] = "hvc_console"; |
791 | ||
792 | static struct vio_device_id hvc_driver_table[] __devinitdata= { | |
793 | {"serial", "hvterm1"}, | |
794 | { NULL, } | |
795 | }; | |
796 | MODULE_DEVICE_TABLE(vio, hvc_driver_table); | |
797 | ||
1da177e4 LT |
798 | static struct vio_driver hvc_vio_driver = { |
799 | .name = hvc_driver_name, | |
800 | .id_table = hvc_driver_table, | |
801 | .probe = hvc_probe, | |
802 | .remove = hvc_remove, | |
803 | }; | |
804 | ||
805 | /* Driver initialization. Follow console initialization. This is where the TTY | |
806 | * interfaces start to become available. */ | |
807 | int __init hvc_init(void) | |
808 | { | |
809 | int rc; | |
810 | ||
5f6d9c07 | 811 | /* We need more than hvc_count adapters due to hotplug additions. */ |
1da177e4 | 812 | hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
1da177e4 LT |
813 | if (!hvc_driver) |
814 | return -ENOMEM; | |
815 | ||
816 | hvc_driver->owner = THIS_MODULE; | |
817 | hvc_driver->devfs_name = "hvc/"; | |
818 | hvc_driver->driver_name = "hvc"; | |
819 | hvc_driver->name = "hvc"; | |
820 | hvc_driver->major = HVC_MAJOR; | |
821 | hvc_driver->minor_start = HVC_MINOR; | |
822 | hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM; | |
823 | hvc_driver->init_termios = tty_std_termios; | |
824 | hvc_driver->flags = TTY_DRIVER_REAL_RAW; | |
825 | tty_set_operations(hvc_driver, &hvc_ops); | |
826 | ||
827 | if (tty_register_driver(hvc_driver)) | |
828 | panic("Couldn't register hvc console driver\n"); | |
829 | ||
830 | /* Always start the kthread because there can be hotplug vty adapters | |
831 | * added later. */ | |
832 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
833 | if (IS_ERR(hvc_task)) { | |
834 | panic("Couldn't create kthread for console.\n"); | |
835 | put_tty_driver(hvc_driver); | |
836 | return -EIO; | |
837 | } | |
838 | ||
839 | /* Register as a vio device to receive callbacks */ | |
840 | rc = vio_register_driver(&hvc_vio_driver); | |
841 | ||
842 | return rc; | |
843 | } | |
837dcfaf | 844 | module_init(hvc_init); |
1da177e4 | 845 | |
320da0d2 MM |
846 | /* This isn't particularily necessary due to this being a console driver |
847 | * but it is nice to be thorough. | |
848 | */ | |
1da177e4 LT |
849 | static void __exit hvc_exit(void) |
850 | { | |
851 | kthread_stop(hvc_task); | |
852 | ||
853 | vio_unregister_driver(&hvc_vio_driver); | |
854 | tty_unregister_driver(hvc_driver); | |
855 | /* return tty_struct instances allocated in hvc_init(). */ | |
856 | put_tty_driver(hvc_driver); | |
320da0d2 | 857 | unregister_console(&hvc_con_driver); |
1da177e4 | 858 | } |
1da177e4 | 859 | module_exit(hvc_exit); |