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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> | |
41 | #include <asm/uaccess.h> | |
42 | #include <asm/hvconsole.h> | |
43 | #include <asm/vio.h> | |
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; | |
88 | int irq_requested; | |
89 | int irq; | |
90 | struct list_head next; | |
91 | struct kobject kobj; /* ref count & hvc_struct lifetime */ | |
92 | struct vio_dev *vdev; | |
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 | */ | |
146 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES]; | |
147 | ||
148 | /* Used for accounting purposes */ | |
149 | static int num_vterms = 0; | |
150 | ||
837dcfaf MM |
151 | /* |
152 | * Console APIs, NOT TTY. These APIs are available immediately when | |
153 | * hvc_console_setup() finds adapters. | |
154 | */ | |
155 | ||
156 | void hvc_console_print(struct console *co, const char *b, unsigned count) | |
157 | { | |
158 | char c[16] __ALIGNED__; | |
159 | unsigned i = 0, n = 0; | |
160 | int r, donecr = 0; | |
161 | ||
162 | /* Console access attempt outside of acceptable console range. */ | |
163 | if (co->index >= MAX_NR_HVC_CONSOLES) | |
164 | return; | |
165 | ||
166 | /* This console adapter was removed so it is not useable. */ | |
167 | if (vtermnos[co->index] < 0) | |
168 | return; | |
169 | ||
170 | while (count > 0 || i > 0) { | |
171 | if (count > 0 && i < sizeof(c)) { | |
172 | if (b[n] == '\n' && !donecr) { | |
173 | c[i++] = '\r'; | |
174 | donecr = 1; | |
175 | } else { | |
176 | c[i++] = b[n++]; | |
177 | donecr = 0; | |
178 | --count; | |
179 | } | |
180 | } else { | |
181 | r = hvc_put_chars(vtermnos[co->index], c, i); | |
182 | if (r < 0) { | |
183 | /* throw away chars on error */ | |
184 | i = 0; | |
185 | } else if (r > 0) { | |
186 | i -= r; | |
187 | if (i > 0) | |
188 | memmove(c, c+r, i); | |
189 | } | |
190 | } | |
191 | } | |
192 | } | |
193 | ||
194 | static struct tty_driver *hvc_console_device(struct console *c, int *index) | |
195 | { | |
196 | *index = c->index; | |
197 | return hvc_driver; | |
198 | } | |
199 | ||
200 | static int __init hvc_console_setup(struct console *co, char *options) | |
201 | { | |
202 | return 0; | |
203 | } | |
204 | ||
205 | struct console hvc_con_driver = { | |
206 | .name = "hvc", | |
207 | .write = hvc_console_print, | |
208 | .device = hvc_console_device, | |
209 | .setup = hvc_console_setup, | |
210 | .flags = CON_PRINTBUFFER, | |
211 | .index = -1, | |
212 | }; | |
213 | ||
214 | /* Early console initialization. Preceeds driver initialization. */ | |
215 | static int __init hvc_console_init(void) | |
216 | { | |
217 | int i; | |
218 | ||
219 | for (i=0; i<MAX_NR_HVC_CONSOLES; i++) | |
220 | vtermnos[i] = -1; | |
221 | num_vterms = hvc_find_vtys(); | |
222 | register_console(&hvc_con_driver); | |
223 | return 0; | |
224 | } | |
225 | console_initcall(hvc_console_init); | |
1da177e4 LT |
226 | |
227 | /* | |
6f24808e MM |
228 | * hvc_instantiate() is an early console discovery method which locates |
229 | * consoles * prior to the vio subsystem discovering them. Hotplugged | |
230 | * vty adapters do NOT get an hvc_instantiate() callback since they | |
231 | * appear after early console init. | |
1da177e4 | 232 | */ |
837dcfaf MM |
233 | int hvc_instantiate(uint32_t vtermno, int index) |
234 | { | |
235 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) | |
236 | return -1; | |
1da177e4 | 237 | |
837dcfaf MM |
238 | if (vtermnos[index] != -1) |
239 | return -1; | |
240 | ||
241 | vtermnos[index] = vtermno; | |
6f24808e MM |
242 | |
243 | /* reserve all indices upto and including this index */ | |
244 | if (last_hvc < index) | |
245 | last_hvc = index; | |
246 | ||
837dcfaf MM |
247 | return 0; |
248 | } | |
1da177e4 LT |
249 | |
250 | /* Wake the sleeping khvcd */ | |
251 | static void hvc_kick(void) | |
252 | { | |
253 | hvc_kicked = 1; | |
254 | wake_up_process(hvc_task); | |
255 | } | |
256 | ||
8b67f8c1 MM |
257 | static int hvc_poll(struct hvc_struct *hp); |
258 | ||
1da177e4 LT |
259 | /* |
260 | * NOTE: This API isn't used if the console adapter doesn't support interrupts. | |
261 | * In this case the console is poll driven. | |
262 | */ | |
263 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs) | |
264 | { | |
8b67f8c1 MM |
265 | /* if hvc_poll request a repoll, then kick the hvcd thread */ |
266 | if (hvc_poll(dev_instance)) | |
267 | hvc_kick(); | |
1da177e4 LT |
268 | return IRQ_HANDLED; |
269 | } | |
270 | ||
271 | static void hvc_unthrottle(struct tty_struct *tty) | |
272 | { | |
273 | hvc_kick(); | |
274 | } | |
275 | ||
1da177e4 LT |
276 | /* |
277 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
278 | * adapter to the kernel. | |
279 | */ | |
280 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
281 | { | |
282 | struct hvc_struct *hp; | |
283 | unsigned long flags; | |
284 | int irq = NO_IRQ; | |
285 | int rc = 0; | |
286 | struct kobject *kobjp; | |
287 | ||
288 | /* Auto increments kobject reference if found. */ | |
289 | if (!(hp = hvc_get_by_index(tty->index))) { | |
290 | printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n"); | |
291 | return -ENODEV; | |
292 | } | |
293 | ||
294 | spin_lock_irqsave(&hp->lock, flags); | |
295 | /* Check and then increment for fast path open. */ | |
296 | if (hp->count++ > 0) { | |
297 | spin_unlock_irqrestore(&hp->lock, flags); | |
298 | hvc_kick(); | |
299 | return 0; | |
300 | } /* else count == 0 */ | |
301 | ||
302 | tty->driver_data = hp; | |
303 | hp->tty = tty; | |
304 | /* Save for request_irq outside of spin_lock. */ | |
305 | irq = hp->irq; | |
306 | if (irq != NO_IRQ) | |
307 | hp->irq_requested = 1; | |
308 | ||
309 | kobjp = &hp->kobj; | |
310 | ||
311 | spin_unlock_irqrestore(&hp->lock, flags); | |
312 | /* check error, fallback to non-irq */ | |
313 | if (irq != NO_IRQ) | |
314 | rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp); | |
315 | ||
316 | /* | |
317 | * If the request_irq() fails and we return an error. The tty layer | |
318 | * will call hvc_close() after a failed open but we don't want to clean | |
319 | * up there so we'll clean up here and clear out the previously set | |
320 | * tty fields and return the kobject reference. | |
321 | */ | |
322 | if (rc) { | |
323 | spin_lock_irqsave(&hp->lock, flags); | |
324 | hp->tty = NULL; | |
325 | hp->irq_requested = 0; | |
326 | spin_unlock_irqrestore(&hp->lock, flags); | |
327 | tty->driver_data = NULL; | |
328 | kobject_put(kobjp); | |
329 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); | |
330 | } | |
331 | /* Force wakeup of the polling thread */ | |
332 | hvc_kick(); | |
333 | ||
334 | return rc; | |
335 | } | |
336 | ||
337 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
338 | { | |
339 | struct hvc_struct *hp; | |
340 | struct kobject *kobjp; | |
341 | int irq = NO_IRQ; | |
342 | unsigned long flags; | |
343 | ||
344 | if (tty_hung_up_p(filp)) | |
345 | return; | |
346 | ||
347 | /* | |
348 | * No driver_data means that this close was issued after a failed | |
349 | * hvc_open by the tty layer's release_dev() function and we can just | |
350 | * exit cleanly because the kobject reference wasn't made. | |
351 | */ | |
352 | if (!tty->driver_data) | |
353 | return; | |
354 | ||
355 | hp = tty->driver_data; | |
356 | spin_lock_irqsave(&hp->lock, flags); | |
357 | ||
358 | kobjp = &hp->kobj; | |
359 | if (--hp->count == 0) { | |
360 | if (hp->irq_requested) | |
361 | irq = hp->irq; | |
362 | hp->irq_requested = 0; | |
363 | ||
364 | /* We are done with the tty pointer now. */ | |
365 | hp->tty = NULL; | |
366 | spin_unlock_irqrestore(&hp->lock, flags); | |
367 | ||
368 | /* | |
369 | * Chain calls chars_in_buffer() and returns immediately if | |
370 | * there is no buffered data otherwise sleeps on a wait queue | |
371 | * waking periodically to check chars_in_buffer(). | |
372 | */ | |
373 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
374 | ||
375 | if (irq != NO_IRQ) | |
376 | free_irq(irq, hp); | |
377 | ||
378 | } else { | |
379 | if (hp->count < 0) | |
380 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
381 | hp->vtermno, hp->count); | |
382 | spin_unlock_irqrestore(&hp->lock, flags); | |
383 | } | |
384 | ||
385 | kobject_put(kobjp); | |
386 | } | |
387 | ||
388 | static void hvc_hangup(struct tty_struct *tty) | |
389 | { | |
390 | struct hvc_struct *hp = tty->driver_data; | |
391 | unsigned long flags; | |
392 | int irq = NO_IRQ; | |
393 | int temp_open_count; | |
394 | struct kobject *kobjp; | |
395 | ||
396 | if (!hp) | |
397 | return; | |
398 | ||
399 | spin_lock_irqsave(&hp->lock, flags); | |
400 | ||
401 | /* | |
402 | * The N_TTY line discipline has problems such that in a close vs | |
403 | * open->hangup case this can be called after the final close so prevent | |
404 | * that from happening for now. | |
405 | */ | |
406 | if (hp->count <= 0) { | |
407 | spin_unlock_irqrestore(&hp->lock, flags); | |
408 | return; | |
409 | } | |
410 | ||
411 | kobjp = &hp->kobj; | |
412 | temp_open_count = hp->count; | |
413 | hp->count = 0; | |
414 | hp->n_outbuf = 0; | |
415 | hp->tty = NULL; | |
416 | if (hp->irq_requested) | |
417 | /* Saved for use outside of spin_lock. */ | |
418 | irq = hp->irq; | |
419 | hp->irq_requested = 0; | |
420 | spin_unlock_irqrestore(&hp->lock, flags); | |
421 | if (irq != NO_IRQ) | |
422 | free_irq(irq, hp); | |
423 | while(temp_open_count) { | |
424 | --temp_open_count; | |
425 | kobject_put(kobjp); | |
426 | } | |
427 | } | |
428 | ||
429 | /* | |
430 | * Push buffered characters whether they were just recently buffered or waiting | |
431 | * on a blocked hypervisor. Call this function with hp->lock held. | |
432 | */ | |
433 | static void hvc_push(struct hvc_struct *hp) | |
434 | { | |
435 | int n; | |
436 | ||
437 | n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); | |
438 | if (n <= 0) { | |
439 | if (n == 0) | |
440 | return; | |
441 | /* throw away output on error; this happens when | |
442 | there is no session connected to the vterm. */ | |
443 | hp->n_outbuf = 0; | |
444 | } else | |
445 | hp->n_outbuf -= n; | |
446 | if (hp->n_outbuf > 0) | |
447 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
448 | else | |
449 | hp->do_wakeup = 1; | |
450 | } | |
451 | ||
452 | static inline int __hvc_write_kernel(struct hvc_struct *hp, | |
453 | const unsigned char *buf, int count) | |
454 | { | |
455 | unsigned long flags; | |
456 | int rsize, written = 0; | |
457 | ||
458 | spin_lock_irqsave(&hp->lock, flags); | |
459 | ||
460 | /* Push pending writes */ | |
461 | if (hp->n_outbuf > 0) | |
462 | hvc_push(hp); | |
463 | ||
464 | while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { | |
465 | if (rsize > count) | |
466 | rsize = count; | |
467 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
468 | count -= rsize; | |
469 | buf += rsize; | |
470 | hp->n_outbuf += rsize; | |
471 | written += rsize; | |
472 | hvc_push(hp); | |
473 | } | |
474 | spin_unlock_irqrestore(&hp->lock, flags); | |
475 | ||
476 | return written; | |
477 | } | |
478 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
479 | { | |
480 | struct hvc_struct *hp = tty->driver_data; | |
481 | int written; | |
482 | ||
483 | /* This write was probably executed during a tty close. */ | |
484 | if (!hp) | |
485 | return -EPIPE; | |
486 | ||
487 | if (hp->count <= 0) | |
488 | return -EIO; | |
489 | ||
490 | written = __hvc_write_kernel(hp, buf, count); | |
491 | ||
492 | /* | |
493 | * Racy, but harmless, kick thread if there is still pending data. | |
494 | * There really is nothing wrong with kicking the thread, even if there | |
495 | * is no buffered data. | |
496 | */ | |
497 | if (hp->n_outbuf) | |
498 | hvc_kick(); | |
499 | ||
500 | return written; | |
501 | } | |
502 | ||
503 | /* | |
504 | * This is actually a contract between the driver and the tty layer outlining | |
505 | * how much write room the driver can guarentee will be sent OR BUFFERED. This | |
506 | * driver MUST honor the return value. | |
507 | */ | |
508 | static int hvc_write_room(struct tty_struct *tty) | |
509 | { | |
510 | struct hvc_struct *hp = tty->driver_data; | |
511 | ||
512 | if (!hp) | |
513 | return -1; | |
514 | ||
515 | return N_OUTBUF - hp->n_outbuf; | |
516 | } | |
517 | ||
518 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
519 | { | |
520 | struct hvc_struct *hp = tty->driver_data; | |
521 | ||
522 | if (!hp) | |
523 | return -1; | |
524 | return hp->n_outbuf; | |
525 | } | |
526 | ||
527 | #define HVC_POLL_READ 0x00000001 | |
528 | #define HVC_POLL_WRITE 0x00000002 | |
529 | #define HVC_POLL_QUICK 0x00000004 | |
530 | ||
531 | static int hvc_poll(struct hvc_struct *hp) | |
532 | { | |
533 | struct tty_struct *tty; | |
534 | int i, n, poll_mask = 0; | |
535 | char buf[N_INBUF] __ALIGNED__; | |
536 | unsigned long flags; | |
537 | int read_total = 0; | |
538 | ||
539 | spin_lock_irqsave(&hp->lock, flags); | |
540 | ||
541 | /* Push pending writes */ | |
542 | if (hp->n_outbuf > 0) | |
543 | hvc_push(hp); | |
544 | /* Reschedule us if still some write pending */ | |
545 | if (hp->n_outbuf > 0) | |
546 | poll_mask |= HVC_POLL_WRITE; | |
547 | ||
548 | /* No tty attached, just skip */ | |
549 | tty = hp->tty; | |
550 | if (tty == NULL) | |
551 | goto bail; | |
552 | ||
553 | /* Now check if we can get data (are we throttled ?) */ | |
554 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
555 | goto throttled; | |
556 | ||
557 | /* If we aren't interrupt driven and aren't throttled, we always | |
558 | * request a reschedule | |
559 | */ | |
560 | if (hp->irq == NO_IRQ) | |
561 | poll_mask |= HVC_POLL_READ; | |
562 | ||
563 | /* Read data if any */ | |
564 | for (;;) { | |
565 | int count = N_INBUF; | |
566 | if (count > (TTY_FLIPBUF_SIZE - tty->flip.count)) | |
567 | count = TTY_FLIPBUF_SIZE - tty->flip.count; | |
568 | ||
569 | /* If flip is full, just reschedule a later read */ | |
570 | if (count == 0) { | |
571 | poll_mask |= HVC_POLL_READ; | |
572 | break; | |
573 | } | |
574 | ||
575 | n = hvc_get_chars(hp->vtermno, buf, count); | |
576 | if (n <= 0) { | |
577 | /* Hangup the tty when disconnected from host */ | |
578 | if (n == -EPIPE) { | |
579 | spin_unlock_irqrestore(&hp->lock, flags); | |
580 | tty_hangup(tty); | |
581 | spin_lock_irqsave(&hp->lock, flags); | |
582 | } | |
583 | break; | |
584 | } | |
585 | for (i = 0; i < n; ++i) { | |
586 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
587 | if (hp->index == hvc_con_driver.index) { |
588 | /* Handle the SysRq Hack */ | |
589 | /* XXX should support a sequence */ | |
590 | if (buf[i] == '\x0f') { /* ^O */ | |
591 | sysrq_pressed = 1; | |
592 | continue; | |
593 | } else if (sysrq_pressed) { | |
594 | handle_sysrq(buf[i], NULL, tty); | |
595 | sysrq_pressed = 0; | |
596 | continue; | |
597 | } | |
1da177e4 LT |
598 | } |
599 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
600 | tty_insert_flip_char(tty, buf[i], 0); | |
601 | } | |
602 | ||
603 | if (tty->flip.count) | |
604 | tty_schedule_flip(tty); | |
605 | ||
606 | /* | |
607 | * Account for the total amount read in one loop, and if above | |
8b67f8c1 MM |
608 | * 64 bytes, we do a quick schedule loop to let the tty grok |
609 | * the data and eventually throttle us. | |
1da177e4 LT |
610 | */ |
611 | read_total += n; | |
612 | if (read_total >= 64) { | |
613 | poll_mask |= HVC_POLL_QUICK; | |
614 | break; | |
615 | } | |
616 | } | |
617 | throttled: | |
618 | /* Wakeup write queue if necessary */ | |
619 | if (hp->do_wakeup) { | |
620 | hp->do_wakeup = 0; | |
621 | tty_wakeup(tty); | |
622 | } | |
623 | bail: | |
624 | spin_unlock_irqrestore(&hp->lock, flags); | |
625 | ||
626 | return poll_mask; | |
627 | } | |
628 | ||
629 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
630 | extern cpumask_t cpus_in_xmon; | |
631 | #else | |
632 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
633 | #endif | |
634 | ||
635 | /* | |
636 | * This kthread is either polling or interrupt driven. This is determined by | |
637 | * calling hvc_poll() who determines whether a console adapter support | |
638 | * interrupts. | |
639 | */ | |
640 | int khvcd(void *unused) | |
641 | { | |
642 | int poll_mask; | |
643 | struct hvc_struct *hp; | |
644 | ||
645 | __set_current_state(TASK_RUNNING); | |
646 | do { | |
647 | poll_mask = 0; | |
648 | hvc_kicked = 0; | |
649 | wmb(); | |
650 | if (cpus_empty(cpus_in_xmon)) { | |
651 | spin_lock(&hvc_structs_lock); | |
652 | list_for_each_entry(hp, &hvc_structs, next) { | |
653 | /*hp = list_entry(node, struct hvc_struct, * next); */ | |
654 | poll_mask |= hvc_poll(hp); | |
655 | } | |
656 | spin_unlock(&hvc_structs_lock); | |
657 | } else | |
658 | poll_mask |= HVC_POLL_READ; | |
659 | if (hvc_kicked) | |
660 | continue; | |
661 | if (poll_mask & HVC_POLL_QUICK) { | |
662 | yield(); | |
663 | continue; | |
664 | } | |
665 | set_current_state(TASK_INTERRUPTIBLE); | |
666 | if (!hvc_kicked) { | |
667 | if (poll_mask == 0) | |
668 | schedule(); | |
669 | else | |
670 | msleep_interruptible(TIMEOUT); | |
671 | } | |
672 | __set_current_state(TASK_RUNNING); | |
673 | } while (!kthread_should_stop()); | |
674 | ||
675 | return 0; | |
676 | } | |
677 | ||
678 | static struct tty_operations hvc_ops = { | |
679 | .open = hvc_open, | |
680 | .close = hvc_close, | |
681 | .write = hvc_write, | |
682 | .hangup = hvc_hangup, | |
683 | .unthrottle = hvc_unthrottle, | |
684 | .write_room = hvc_write_room, | |
685 | .chars_in_buffer = hvc_chars_in_buffer, | |
686 | }; | |
687 | ||
1da177e4 LT |
688 | /* callback when the kboject ref count reaches zero. */ |
689 | static void destroy_hvc_struct(struct kobject *kobj) | |
690 | { | |
691 | struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); | |
692 | unsigned long flags; | |
693 | ||
694 | spin_lock(&hvc_structs_lock); | |
695 | ||
696 | spin_lock_irqsave(&hp->lock, flags); | |
697 | list_del(&(hp->next)); | |
698 | spin_unlock_irqrestore(&hp->lock, flags); | |
699 | ||
700 | spin_unlock(&hvc_structs_lock); | |
701 | ||
702 | kfree(hp); | |
703 | } | |
704 | ||
705 | static struct kobj_type hvc_kobj_type = { | |
706 | .release = destroy_hvc_struct, | |
707 | }; | |
708 | ||
709 | static int __devinit hvc_probe( | |
710 | struct vio_dev *dev, | |
711 | const struct vio_device_id *id) | |
712 | { | |
713 | struct hvc_struct *hp; | |
6f24808e | 714 | int i; |
1da177e4 LT |
715 | |
716 | /* probed with invalid parameters. */ | |
717 | if (!dev || !id) | |
718 | return -EPERM; | |
719 | ||
720 | hp = kmalloc(sizeof(*hp), GFP_KERNEL); | |
721 | if (!hp) | |
722 | return -ENOMEM; | |
723 | ||
724 | memset(hp, 0x00, sizeof(*hp)); | |
725 | hp->vtermno = dev->unit_address; | |
726 | hp->vdev = dev; | |
727 | hp->vdev->dev.driver_data = hp; | |
728 | hp->irq = dev->irq; | |
729 | ||
730 | kobject_init(&hp->kobj); | |
731 | hp->kobj.ktype = &hvc_kobj_type; | |
732 | ||
733 | spin_lock_init(&hp->lock); | |
734 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
735 | |
736 | /* | |
737 | * find index to use: | |
738 | * see if this vterm id matches one registered for console. | |
739 | */ | |
740 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
741 | if (vtermnos[i] == hp->vtermno) | |
742 | break; | |
743 | ||
744 | /* no matching slot, just use a counter */ | |
745 | if (i >= MAX_NR_HVC_CONSOLES) | |
746 | i = ++last_hvc; | |
747 | ||
748 | hp->index = i; | |
749 | ||
1da177e4 LT |
750 | list_add_tail(&(hp->next), &hvc_structs); |
751 | spin_unlock(&hvc_structs_lock); | |
752 | ||
753 | return 0; | |
754 | } | |
755 | ||
756 | static int __devexit hvc_remove(struct vio_dev *dev) | |
757 | { | |
758 | struct hvc_struct *hp = dev->dev.driver_data; | |
759 | unsigned long flags; | |
760 | struct kobject *kobjp; | |
761 | struct tty_struct *tty; | |
762 | ||
763 | spin_lock_irqsave(&hp->lock, flags); | |
764 | tty = hp->tty; | |
765 | kobjp = &hp->kobj; | |
766 | ||
767 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
768 | vtermnos[hp->index] = -1; | |
769 | ||
770 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
771 | ||
772 | spin_unlock_irqrestore(&hp->lock, flags); | |
773 | ||
774 | /* | |
775 | * We 'put' the instance that was grabbed when the kobject instance | |
776 | * was intialized using kobject_init(). Let the last holder of this | |
777 | * kobject cause it to be removed, which will probably be the tty_hangup | |
778 | * below. | |
779 | */ | |
780 | kobject_put(kobjp); | |
781 | ||
782 | /* | |
783 | * This function call will auto chain call hvc_hangup. The tty should | |
784 | * always be valid at this time unless a simultaneous tty close already | |
785 | * cleaned up the hvc_struct. | |
786 | */ | |
787 | if (tty) | |
788 | tty_hangup(tty); | |
789 | return 0; | |
790 | } | |
791 | ||
837dcfaf MM |
792 | char hvc_driver_name[] = "hvc_console"; |
793 | ||
794 | static struct vio_device_id hvc_driver_table[] __devinitdata= { | |
795 | {"serial", "hvterm1"}, | |
796 | { NULL, } | |
797 | }; | |
798 | MODULE_DEVICE_TABLE(vio, hvc_driver_table); | |
799 | ||
1da177e4 LT |
800 | static struct vio_driver hvc_vio_driver = { |
801 | .name = hvc_driver_name, | |
802 | .id_table = hvc_driver_table, | |
803 | .probe = hvc_probe, | |
804 | .remove = hvc_remove, | |
805 | }; | |
806 | ||
807 | /* Driver initialization. Follow console initialization. This is where the TTY | |
808 | * interfaces start to become available. */ | |
809 | int __init hvc_init(void) | |
810 | { | |
811 | int rc; | |
812 | ||
813 | /* We need more than num_vterms adapters due to hotplug additions. */ | |
814 | hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); | |
815 | /* hvc_driver = alloc_tty_driver(num_vterms); */ | |
816 | if (!hvc_driver) | |
817 | return -ENOMEM; | |
818 | ||
819 | hvc_driver->owner = THIS_MODULE; | |
820 | hvc_driver->devfs_name = "hvc/"; | |
821 | hvc_driver->driver_name = "hvc"; | |
822 | hvc_driver->name = "hvc"; | |
823 | hvc_driver->major = HVC_MAJOR; | |
824 | hvc_driver->minor_start = HVC_MINOR; | |
825 | hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM; | |
826 | hvc_driver->init_termios = tty_std_termios; | |
827 | hvc_driver->flags = TTY_DRIVER_REAL_RAW; | |
828 | tty_set_operations(hvc_driver, &hvc_ops); | |
829 | ||
830 | if (tty_register_driver(hvc_driver)) | |
831 | panic("Couldn't register hvc console driver\n"); | |
832 | ||
833 | /* Always start the kthread because there can be hotplug vty adapters | |
834 | * added later. */ | |
835 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
836 | if (IS_ERR(hvc_task)) { | |
837 | panic("Couldn't create kthread for console.\n"); | |
838 | put_tty_driver(hvc_driver); | |
839 | return -EIO; | |
840 | } | |
841 | ||
842 | /* Register as a vio device to receive callbacks */ | |
843 | rc = vio_register_driver(&hvc_vio_driver); | |
844 | ||
845 | return rc; | |
846 | } | |
837dcfaf | 847 | module_init(hvc_init); |
1da177e4 | 848 | |
320da0d2 MM |
849 | /* This isn't particularily necessary due to this being a console driver |
850 | * but it is nice to be thorough. | |
851 | */ | |
1da177e4 LT |
852 | static void __exit hvc_exit(void) |
853 | { | |
854 | kthread_stop(hvc_task); | |
855 | ||
856 | vio_unregister_driver(&hvc_vio_driver); | |
857 | tty_unregister_driver(hvc_driver); | |
858 | /* return tty_struct instances allocated in hvc_init(). */ | |
859 | put_tty_driver(hvc_driver); | |
320da0d2 | 860 | unregister_console(&hvc_con_driver); |
1da177e4 | 861 | } |
1da177e4 | 862 | module_exit(hvc_exit); |