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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 MM |
104 | /* |
105 | * This value is used to associate a tty->index value to a hvc_struct based | |
106 | * upon order of exposure via hvc_probe(). | |
107 | */ | |
108 | static int hvc_count = -1; | |
109 | ||
110 | /* | |
111 | * Do not call this function with either the hvc_strucst_lock or the hvc_struct | |
112 | * lock held. If successful, this function increments the kobject reference | |
113 | * count against the target hvc_struct so it should be released when finished. | |
114 | */ | |
115 | struct hvc_struct *hvc_get_by_index(int index) | |
116 | { | |
117 | struct hvc_struct *hp; | |
118 | unsigned long flags; | |
119 | ||
120 | spin_lock(&hvc_structs_lock); | |
121 | ||
122 | list_for_each_entry(hp, &hvc_structs, next) { | |
123 | spin_lock_irqsave(&hp->lock, flags); | |
124 | if (hp->index == index) { | |
125 | kobject_get(&hp->kobj); | |
126 | spin_unlock_irqrestore(&hp->lock, flags); | |
127 | spin_unlock(&hvc_structs_lock); | |
128 | return hp; | |
129 | } | |
130 | spin_unlock_irqrestore(&hp->lock, flags); | |
131 | } | |
132 | hp = NULL; | |
133 | ||
134 | spin_unlock(&hvc_structs_lock); | |
135 | return hp; | |
136 | } | |
137 | ||
138 | ||
1da177e4 LT |
139 | /* |
140 | * Initial console vtermnos for console API usage prior to full console | |
141 | * initialization. Any vty adapter outside this range will not have usable | |
142 | * console interfaces but can still be used as a tty device. This has to be | |
143 | * static because kmalloc will not work during early console init. | |
144 | */ | |
145 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES]; | |
146 | ||
147 | /* Used for accounting purposes */ | |
148 | static int num_vterms = 0; | |
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; | |
220 | num_vterms = hvc_find_vtys(); | |
221 | register_console(&hvc_con_driver); | |
222 | return 0; | |
223 | } | |
224 | console_initcall(hvc_console_init); | |
1da177e4 LT |
225 | |
226 | /* | |
837dcfaf MM |
227 | * hvc_instantiate() is an early console discovery method which locates consoles |
228 | * prior to the vio subsystem discovering them. Hotplugged vty adapters do NOT | |
229 | * get an hvc_instantiate() callback since the appear after early console init. | |
1da177e4 | 230 | */ |
837dcfaf MM |
231 | int hvc_instantiate(uint32_t vtermno, int index) |
232 | { | |
233 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) | |
234 | return -1; | |
1da177e4 | 235 | |
837dcfaf MM |
236 | if (vtermnos[index] != -1) |
237 | return -1; | |
238 | ||
239 | vtermnos[index] = vtermno; | |
240 | return 0; | |
241 | } | |
1da177e4 LT |
242 | |
243 | /* Wake the sleeping khvcd */ | |
244 | static void hvc_kick(void) | |
245 | { | |
246 | hvc_kicked = 1; | |
247 | wake_up_process(hvc_task); | |
248 | } | |
249 | ||
250 | /* | |
251 | * NOTE: This API isn't used if the console adapter doesn't support interrupts. | |
252 | * In this case the console is poll driven. | |
253 | */ | |
254 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs) | |
255 | { | |
256 | hvc_kick(); | |
257 | return IRQ_HANDLED; | |
258 | } | |
259 | ||
260 | static void hvc_unthrottle(struct tty_struct *tty) | |
261 | { | |
262 | hvc_kick(); | |
263 | } | |
264 | ||
1da177e4 LT |
265 | /* |
266 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
267 | * adapter to the kernel. | |
268 | */ | |
269 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
270 | { | |
271 | struct hvc_struct *hp; | |
272 | unsigned long flags; | |
273 | int irq = NO_IRQ; | |
274 | int rc = 0; | |
275 | struct kobject *kobjp; | |
276 | ||
277 | /* Auto increments kobject reference if found. */ | |
278 | if (!(hp = hvc_get_by_index(tty->index))) { | |
279 | printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n"); | |
280 | return -ENODEV; | |
281 | } | |
282 | ||
283 | spin_lock_irqsave(&hp->lock, flags); | |
284 | /* Check and then increment for fast path open. */ | |
285 | if (hp->count++ > 0) { | |
286 | spin_unlock_irqrestore(&hp->lock, flags); | |
287 | hvc_kick(); | |
288 | return 0; | |
289 | } /* else count == 0 */ | |
290 | ||
291 | tty->driver_data = hp; | |
292 | hp->tty = tty; | |
293 | /* Save for request_irq outside of spin_lock. */ | |
294 | irq = hp->irq; | |
295 | if (irq != NO_IRQ) | |
296 | hp->irq_requested = 1; | |
297 | ||
298 | kobjp = &hp->kobj; | |
299 | ||
300 | spin_unlock_irqrestore(&hp->lock, flags); | |
301 | /* check error, fallback to non-irq */ | |
302 | if (irq != NO_IRQ) | |
303 | rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp); | |
304 | ||
305 | /* | |
306 | * If the request_irq() fails and we return an error. The tty layer | |
307 | * will call hvc_close() after a failed open but we don't want to clean | |
308 | * up there so we'll clean up here and clear out the previously set | |
309 | * tty fields and return the kobject reference. | |
310 | */ | |
311 | if (rc) { | |
312 | spin_lock_irqsave(&hp->lock, flags); | |
313 | hp->tty = NULL; | |
314 | hp->irq_requested = 0; | |
315 | spin_unlock_irqrestore(&hp->lock, flags); | |
316 | tty->driver_data = NULL; | |
317 | kobject_put(kobjp); | |
318 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); | |
319 | } | |
320 | /* Force wakeup of the polling thread */ | |
321 | hvc_kick(); | |
322 | ||
323 | return rc; | |
324 | } | |
325 | ||
326 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
327 | { | |
328 | struct hvc_struct *hp; | |
329 | struct kobject *kobjp; | |
330 | int irq = NO_IRQ; | |
331 | unsigned long flags; | |
332 | ||
333 | if (tty_hung_up_p(filp)) | |
334 | return; | |
335 | ||
336 | /* | |
337 | * No driver_data means that this close was issued after a failed | |
338 | * hvc_open by the tty layer's release_dev() function and we can just | |
339 | * exit cleanly because the kobject reference wasn't made. | |
340 | */ | |
341 | if (!tty->driver_data) | |
342 | return; | |
343 | ||
344 | hp = tty->driver_data; | |
345 | spin_lock_irqsave(&hp->lock, flags); | |
346 | ||
347 | kobjp = &hp->kobj; | |
348 | if (--hp->count == 0) { | |
349 | if (hp->irq_requested) | |
350 | irq = hp->irq; | |
351 | hp->irq_requested = 0; | |
352 | ||
353 | /* We are done with the tty pointer now. */ | |
354 | hp->tty = NULL; | |
355 | spin_unlock_irqrestore(&hp->lock, flags); | |
356 | ||
357 | /* | |
358 | * Chain calls chars_in_buffer() and returns immediately if | |
359 | * there is no buffered data otherwise sleeps on a wait queue | |
360 | * waking periodically to check chars_in_buffer(). | |
361 | */ | |
362 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
363 | ||
364 | if (irq != NO_IRQ) | |
365 | free_irq(irq, hp); | |
366 | ||
367 | } else { | |
368 | if (hp->count < 0) | |
369 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
370 | hp->vtermno, hp->count); | |
371 | spin_unlock_irqrestore(&hp->lock, flags); | |
372 | } | |
373 | ||
374 | kobject_put(kobjp); | |
375 | } | |
376 | ||
377 | static void hvc_hangup(struct tty_struct *tty) | |
378 | { | |
379 | struct hvc_struct *hp = tty->driver_data; | |
380 | unsigned long flags; | |
381 | int irq = NO_IRQ; | |
382 | int temp_open_count; | |
383 | struct kobject *kobjp; | |
384 | ||
385 | if (!hp) | |
386 | return; | |
387 | ||
388 | spin_lock_irqsave(&hp->lock, flags); | |
389 | ||
390 | /* | |
391 | * The N_TTY line discipline has problems such that in a close vs | |
392 | * open->hangup case this can be called after the final close so prevent | |
393 | * that from happening for now. | |
394 | */ | |
395 | if (hp->count <= 0) { | |
396 | spin_unlock_irqrestore(&hp->lock, flags); | |
397 | return; | |
398 | } | |
399 | ||
400 | kobjp = &hp->kobj; | |
401 | temp_open_count = hp->count; | |
402 | hp->count = 0; | |
403 | hp->n_outbuf = 0; | |
404 | hp->tty = NULL; | |
405 | if (hp->irq_requested) | |
406 | /* Saved for use outside of spin_lock. */ | |
407 | irq = hp->irq; | |
408 | hp->irq_requested = 0; | |
409 | spin_unlock_irqrestore(&hp->lock, flags); | |
410 | if (irq != NO_IRQ) | |
411 | free_irq(irq, hp); | |
412 | while(temp_open_count) { | |
413 | --temp_open_count; | |
414 | kobject_put(kobjp); | |
415 | } | |
416 | } | |
417 | ||
418 | /* | |
419 | * Push buffered characters whether they were just recently buffered or waiting | |
420 | * on a blocked hypervisor. Call this function with hp->lock held. | |
421 | */ | |
422 | static void hvc_push(struct hvc_struct *hp) | |
423 | { | |
424 | int n; | |
425 | ||
426 | n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); | |
427 | if (n <= 0) { | |
428 | if (n == 0) | |
429 | return; | |
430 | /* throw away output on error; this happens when | |
431 | there is no session connected to the vterm. */ | |
432 | hp->n_outbuf = 0; | |
433 | } else | |
434 | hp->n_outbuf -= n; | |
435 | if (hp->n_outbuf > 0) | |
436 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
437 | else | |
438 | hp->do_wakeup = 1; | |
439 | } | |
440 | ||
441 | static inline int __hvc_write_kernel(struct hvc_struct *hp, | |
442 | const unsigned char *buf, int count) | |
443 | { | |
444 | unsigned long flags; | |
445 | int rsize, written = 0; | |
446 | ||
447 | spin_lock_irqsave(&hp->lock, flags); | |
448 | ||
449 | /* Push pending writes */ | |
450 | if (hp->n_outbuf > 0) | |
451 | hvc_push(hp); | |
452 | ||
453 | while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) { | |
454 | if (rsize > count) | |
455 | rsize = count; | |
456 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
457 | count -= rsize; | |
458 | buf += rsize; | |
459 | hp->n_outbuf += rsize; | |
460 | written += rsize; | |
461 | hvc_push(hp); | |
462 | } | |
463 | spin_unlock_irqrestore(&hp->lock, flags); | |
464 | ||
465 | return written; | |
466 | } | |
467 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
468 | { | |
469 | struct hvc_struct *hp = tty->driver_data; | |
470 | int written; | |
471 | ||
472 | /* This write was probably executed during a tty close. */ | |
473 | if (!hp) | |
474 | return -EPIPE; | |
475 | ||
476 | if (hp->count <= 0) | |
477 | return -EIO; | |
478 | ||
479 | written = __hvc_write_kernel(hp, buf, count); | |
480 | ||
481 | /* | |
482 | * Racy, but harmless, kick thread if there is still pending data. | |
483 | * There really is nothing wrong with kicking the thread, even if there | |
484 | * is no buffered data. | |
485 | */ | |
486 | if (hp->n_outbuf) | |
487 | hvc_kick(); | |
488 | ||
489 | return written; | |
490 | } | |
491 | ||
492 | /* | |
493 | * This is actually a contract between the driver and the tty layer outlining | |
494 | * how much write room the driver can guarentee will be sent OR BUFFERED. This | |
495 | * driver MUST honor the return value. | |
496 | */ | |
497 | static int hvc_write_room(struct tty_struct *tty) | |
498 | { | |
499 | struct hvc_struct *hp = tty->driver_data; | |
500 | ||
501 | if (!hp) | |
502 | return -1; | |
503 | ||
504 | return N_OUTBUF - hp->n_outbuf; | |
505 | } | |
506 | ||
507 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
508 | { | |
509 | struct hvc_struct *hp = tty->driver_data; | |
510 | ||
511 | if (!hp) | |
512 | return -1; | |
513 | return hp->n_outbuf; | |
514 | } | |
515 | ||
516 | #define HVC_POLL_READ 0x00000001 | |
517 | #define HVC_POLL_WRITE 0x00000002 | |
518 | #define HVC_POLL_QUICK 0x00000004 | |
519 | ||
520 | static int hvc_poll(struct hvc_struct *hp) | |
521 | { | |
522 | struct tty_struct *tty; | |
523 | int i, n, poll_mask = 0; | |
524 | char buf[N_INBUF] __ALIGNED__; | |
525 | unsigned long flags; | |
526 | int read_total = 0; | |
527 | ||
528 | spin_lock_irqsave(&hp->lock, flags); | |
529 | ||
530 | /* Push pending writes */ | |
531 | if (hp->n_outbuf > 0) | |
532 | hvc_push(hp); | |
533 | /* Reschedule us if still some write pending */ | |
534 | if (hp->n_outbuf > 0) | |
535 | poll_mask |= HVC_POLL_WRITE; | |
536 | ||
537 | /* No tty attached, just skip */ | |
538 | tty = hp->tty; | |
539 | if (tty == NULL) | |
540 | goto bail; | |
541 | ||
542 | /* Now check if we can get data (are we throttled ?) */ | |
543 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
544 | goto throttled; | |
545 | ||
546 | /* If we aren't interrupt driven and aren't throttled, we always | |
547 | * request a reschedule | |
548 | */ | |
549 | if (hp->irq == NO_IRQ) | |
550 | poll_mask |= HVC_POLL_READ; | |
551 | ||
552 | /* Read data if any */ | |
553 | for (;;) { | |
554 | int count = N_INBUF; | |
555 | if (count > (TTY_FLIPBUF_SIZE - tty->flip.count)) | |
556 | count = TTY_FLIPBUF_SIZE - tty->flip.count; | |
557 | ||
558 | /* If flip is full, just reschedule a later read */ | |
559 | if (count == 0) { | |
560 | poll_mask |= HVC_POLL_READ; | |
561 | break; | |
562 | } | |
563 | ||
564 | n = hvc_get_chars(hp->vtermno, buf, count); | |
565 | if (n <= 0) { | |
566 | /* Hangup the tty when disconnected from host */ | |
567 | if (n == -EPIPE) { | |
568 | spin_unlock_irqrestore(&hp->lock, flags); | |
569 | tty_hangup(tty); | |
570 | spin_lock_irqsave(&hp->lock, flags); | |
571 | } | |
572 | break; | |
573 | } | |
574 | for (i = 0; i < n; ++i) { | |
575 | #ifdef CONFIG_MAGIC_SYSRQ | |
576 | /* Handle the SysRq Hack */ | |
577 | if (buf[i] == '\x0f') { /* ^O -- should support a sequence */ | |
578 | sysrq_pressed = 1; | |
579 | continue; | |
580 | } else if (sysrq_pressed) { | |
581 | handle_sysrq(buf[i], NULL, tty); | |
582 | sysrq_pressed = 0; | |
583 | continue; | |
584 | } | |
585 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
586 | tty_insert_flip_char(tty, buf[i], 0); | |
587 | } | |
588 | ||
589 | if (tty->flip.count) | |
590 | tty_schedule_flip(tty); | |
591 | ||
592 | /* | |
593 | * Account for the total amount read in one loop, and if above | |
594 | * 64 bytes, we do a quick schedule loop to let the tty grok the | |
595 | * data and eventually throttle us. | |
596 | */ | |
597 | read_total += n; | |
598 | if (read_total >= 64) { | |
599 | poll_mask |= HVC_POLL_QUICK; | |
600 | break; | |
601 | } | |
602 | } | |
603 | throttled: | |
604 | /* Wakeup write queue if necessary */ | |
605 | if (hp->do_wakeup) { | |
606 | hp->do_wakeup = 0; | |
607 | tty_wakeup(tty); | |
608 | } | |
609 | bail: | |
610 | spin_unlock_irqrestore(&hp->lock, flags); | |
611 | ||
612 | return poll_mask; | |
613 | } | |
614 | ||
615 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
616 | extern cpumask_t cpus_in_xmon; | |
617 | #else | |
618 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
619 | #endif | |
620 | ||
621 | /* | |
622 | * This kthread is either polling or interrupt driven. This is determined by | |
623 | * calling hvc_poll() who determines whether a console adapter support | |
624 | * interrupts. | |
625 | */ | |
626 | int khvcd(void *unused) | |
627 | { | |
628 | int poll_mask; | |
629 | struct hvc_struct *hp; | |
630 | ||
631 | __set_current_state(TASK_RUNNING); | |
632 | do { | |
633 | poll_mask = 0; | |
634 | hvc_kicked = 0; | |
635 | wmb(); | |
636 | if (cpus_empty(cpus_in_xmon)) { | |
637 | spin_lock(&hvc_structs_lock); | |
638 | list_for_each_entry(hp, &hvc_structs, next) { | |
639 | /*hp = list_entry(node, struct hvc_struct, * next); */ | |
640 | poll_mask |= hvc_poll(hp); | |
641 | } | |
642 | spin_unlock(&hvc_structs_lock); | |
643 | } else | |
644 | poll_mask |= HVC_POLL_READ; | |
645 | if (hvc_kicked) | |
646 | continue; | |
647 | if (poll_mask & HVC_POLL_QUICK) { | |
648 | yield(); | |
649 | continue; | |
650 | } | |
651 | set_current_state(TASK_INTERRUPTIBLE); | |
652 | if (!hvc_kicked) { | |
653 | if (poll_mask == 0) | |
654 | schedule(); | |
655 | else | |
656 | msleep_interruptible(TIMEOUT); | |
657 | } | |
658 | __set_current_state(TASK_RUNNING); | |
659 | } while (!kthread_should_stop()); | |
660 | ||
661 | return 0; | |
662 | } | |
663 | ||
664 | static struct tty_operations hvc_ops = { | |
665 | .open = hvc_open, | |
666 | .close = hvc_close, | |
667 | .write = hvc_write, | |
668 | .hangup = hvc_hangup, | |
669 | .unthrottle = hvc_unthrottle, | |
670 | .write_room = hvc_write_room, | |
671 | .chars_in_buffer = hvc_chars_in_buffer, | |
672 | }; | |
673 | ||
1da177e4 LT |
674 | /* callback when the kboject ref count reaches zero. */ |
675 | static void destroy_hvc_struct(struct kobject *kobj) | |
676 | { | |
677 | struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj); | |
678 | unsigned long flags; | |
679 | ||
680 | spin_lock(&hvc_structs_lock); | |
681 | ||
682 | spin_lock_irqsave(&hp->lock, flags); | |
683 | list_del(&(hp->next)); | |
684 | spin_unlock_irqrestore(&hp->lock, flags); | |
685 | ||
686 | spin_unlock(&hvc_structs_lock); | |
687 | ||
688 | kfree(hp); | |
689 | } | |
690 | ||
691 | static struct kobj_type hvc_kobj_type = { | |
692 | .release = destroy_hvc_struct, | |
693 | }; | |
694 | ||
695 | static int __devinit hvc_probe( | |
696 | struct vio_dev *dev, | |
697 | const struct vio_device_id *id) | |
698 | { | |
699 | struct hvc_struct *hp; | |
700 | ||
701 | /* probed with invalid parameters. */ | |
702 | if (!dev || !id) | |
703 | return -EPERM; | |
704 | ||
705 | hp = kmalloc(sizeof(*hp), GFP_KERNEL); | |
706 | if (!hp) | |
707 | return -ENOMEM; | |
708 | ||
709 | memset(hp, 0x00, sizeof(*hp)); | |
710 | hp->vtermno = dev->unit_address; | |
711 | hp->vdev = dev; | |
712 | hp->vdev->dev.driver_data = hp; | |
713 | hp->irq = dev->irq; | |
714 | ||
715 | kobject_init(&hp->kobj); | |
716 | hp->kobj.ktype = &hvc_kobj_type; | |
717 | ||
718 | spin_lock_init(&hp->lock); | |
719 | spin_lock(&hvc_structs_lock); | |
720 | hp->index = ++hvc_count; | |
721 | list_add_tail(&(hp->next), &hvc_structs); | |
722 | spin_unlock(&hvc_structs_lock); | |
723 | ||
724 | return 0; | |
725 | } | |
726 | ||
727 | static int __devexit hvc_remove(struct vio_dev *dev) | |
728 | { | |
729 | struct hvc_struct *hp = dev->dev.driver_data; | |
730 | unsigned long flags; | |
731 | struct kobject *kobjp; | |
732 | struct tty_struct *tty; | |
733 | ||
734 | spin_lock_irqsave(&hp->lock, flags); | |
735 | tty = hp->tty; | |
736 | kobjp = &hp->kobj; | |
737 | ||
738 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
739 | vtermnos[hp->index] = -1; | |
740 | ||
741 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
742 | ||
743 | spin_unlock_irqrestore(&hp->lock, flags); | |
744 | ||
745 | /* | |
746 | * We 'put' the instance that was grabbed when the kobject instance | |
747 | * was intialized using kobject_init(). Let the last holder of this | |
748 | * kobject cause it to be removed, which will probably be the tty_hangup | |
749 | * below. | |
750 | */ | |
751 | kobject_put(kobjp); | |
752 | ||
753 | /* | |
754 | * This function call will auto chain call hvc_hangup. The tty should | |
755 | * always be valid at this time unless a simultaneous tty close already | |
756 | * cleaned up the hvc_struct. | |
757 | */ | |
758 | if (tty) | |
759 | tty_hangup(tty); | |
760 | return 0; | |
761 | } | |
762 | ||
837dcfaf MM |
763 | char hvc_driver_name[] = "hvc_console"; |
764 | ||
765 | static struct vio_device_id hvc_driver_table[] __devinitdata= { | |
766 | {"serial", "hvterm1"}, | |
767 | { NULL, } | |
768 | }; | |
769 | MODULE_DEVICE_TABLE(vio, hvc_driver_table); | |
770 | ||
1da177e4 LT |
771 | static struct vio_driver hvc_vio_driver = { |
772 | .name = hvc_driver_name, | |
773 | .id_table = hvc_driver_table, | |
774 | .probe = hvc_probe, | |
775 | .remove = hvc_remove, | |
776 | }; | |
777 | ||
778 | /* Driver initialization. Follow console initialization. This is where the TTY | |
779 | * interfaces start to become available. */ | |
780 | int __init hvc_init(void) | |
781 | { | |
782 | int rc; | |
783 | ||
784 | /* We need more than num_vterms adapters due to hotplug additions. */ | |
785 | hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); | |
786 | /* hvc_driver = alloc_tty_driver(num_vterms); */ | |
787 | if (!hvc_driver) | |
788 | return -ENOMEM; | |
789 | ||
790 | hvc_driver->owner = THIS_MODULE; | |
791 | hvc_driver->devfs_name = "hvc/"; | |
792 | hvc_driver->driver_name = "hvc"; | |
793 | hvc_driver->name = "hvc"; | |
794 | hvc_driver->major = HVC_MAJOR; | |
795 | hvc_driver->minor_start = HVC_MINOR; | |
796 | hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM; | |
797 | hvc_driver->init_termios = tty_std_termios; | |
798 | hvc_driver->flags = TTY_DRIVER_REAL_RAW; | |
799 | tty_set_operations(hvc_driver, &hvc_ops); | |
800 | ||
801 | if (tty_register_driver(hvc_driver)) | |
802 | panic("Couldn't register hvc console driver\n"); | |
803 | ||
804 | /* Always start the kthread because there can be hotplug vty adapters | |
805 | * added later. */ | |
806 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
807 | if (IS_ERR(hvc_task)) { | |
808 | panic("Couldn't create kthread for console.\n"); | |
809 | put_tty_driver(hvc_driver); | |
810 | return -EIO; | |
811 | } | |
812 | ||
813 | /* Register as a vio device to receive callbacks */ | |
814 | rc = vio_register_driver(&hvc_vio_driver); | |
815 | ||
816 | return rc; | |
817 | } | |
837dcfaf | 818 | module_init(hvc_init); |
1da177e4 LT |
819 | |
820 | /* This isn't particularily necessary due to this being a console driver but it | |
821 | * is nice to be thorough */ | |
822 | static void __exit hvc_exit(void) | |
823 | { | |
824 | kthread_stop(hvc_task); | |
825 | ||
826 | vio_unregister_driver(&hvc_vio_driver); | |
827 | tty_unregister_driver(hvc_driver); | |
828 | /* return tty_struct instances allocated in hvc_init(). */ | |
829 | put_tty_driver(hvc_driver); | |
830 | } | |
1da177e4 | 831 | module_exit(hvc_exit); |