Commit | Line | Data |
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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> | |
12b20ded | 30 | #include <linux/kref.h> |
1da177e4 LT |
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> | |
7dfb7103 | 41 | #include <linux/freezer.h> |
45d607ed | 42 | |
1da177e4 | 43 | #include <asm/uaccess.h> |
45d607ed RA |
44 | |
45 | #include "hvc_console.h" | |
1da177e4 LT |
46 | |
47 | #define HVC_MAJOR 229 | |
48 | #define HVC_MINOR 0 | |
49 | ||
1da177e4 LT |
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 | /* | |
45d607ed RA |
57 | * These sizes are most efficient for vio, because they are the |
58 | * native transfer size. We could make them selectable in the | |
59 | * future to better deal with backends that want other buffer sizes. | |
1da177e4 | 60 | */ |
1da177e4 LT |
61 | #define N_OUTBUF 16 |
62 | #define N_INBUF 16 | |
63 | ||
45d607ed | 64 | #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
1da177e4 | 65 | |
837dcfaf MM |
66 | static struct tty_driver *hvc_driver; |
67 | static struct task_struct *hvc_task; | |
68 | ||
69 | /* Picks up late kicks after list walk but before schedule() */ | |
70 | static int hvc_kicked; | |
71 | ||
3e6c6f63 RR |
72 | static int hvc_init(void); |
73 | ||
837dcfaf MM |
74 | #ifdef CONFIG_MAGIC_SYSRQ |
75 | static int sysrq_pressed; | |
76 | #endif | |
77 | ||
1da177e4 LT |
78 | struct hvc_struct { |
79 | spinlock_t lock; | |
80 | int index; | |
81 | struct tty_struct *tty; | |
82 | unsigned int count; | |
83 | int do_wakeup; | |
4e9e95a3 SR |
84 | char *outbuf; |
85 | int outbuf_size; | |
1da177e4 LT |
86 | int n_outbuf; |
87 | uint32_t vtermno; | |
030ffad2 | 88 | struct hv_ops *ops; |
1da177e4 LT |
89 | int irq_requested; |
90 | int irq; | |
91 | struct list_head next; | |
12b20ded | 92 | struct kref kref; /* ref count & hvc_struct lifetime */ |
1da177e4 LT |
93 | }; |
94 | ||
95 | /* dynamic list of hvc_struct instances */ | |
bed9759b | 96 | static LIST_HEAD(hvc_structs); |
1da177e4 LT |
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 | |
c3ea6921 | 107 | * a console candidate registered with hvc_instantiate(). |
837dcfaf | 108 | */ |
6f24808e | 109 | static int last_hvc = -1; |
837dcfaf MM |
110 | |
111 | /* | |
c3ea6921 | 112 | * Do not call this function with either the hvc_structs_lock or the hvc_struct |
12b20ded | 113 | * lock held. If successful, this function increments the kref reference |
837dcfaf MM |
114 | * count against the target hvc_struct so it should be released when finished. |
115 | */ | |
4fa156ea | 116 | static struct hvc_struct *hvc_get_by_index(int index) |
837dcfaf MM |
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) { | |
12b20ded | 126 | kref_get(&hp->kref); |
837dcfaf MM |
127 | spin_unlock_irqrestore(&hp->lock, flags); |
128 | spin_unlock(&hvc_structs_lock); | |
129 | return hp; | |
130 | } | |
131 | spin_unlock_irqrestore(&hp->lock, flags); | |
132 | } | |
133 | hp = NULL; | |
134 | ||
135 | spin_unlock(&hvc_structs_lock); | |
136 | return hp; | |
137 | } | |
138 | ||
139 | ||
1da177e4 LT |
140 | /* |
141 | * Initial console vtermnos for console API usage prior to full console | |
142 | * initialization. Any vty adapter outside this range will not have usable | |
143 | * console interfaces but can still be used as a tty device. This has to be | |
144 | * static because kmalloc will not work during early console init. | |
145 | */ | |
030ffad2 | 146 | static struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
64e4da57 MM |
147 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
148 | {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; | |
1da177e4 | 149 | |
837dcfaf MM |
150 | /* |
151 | * Console APIs, NOT TTY. These APIs are available immediately when | |
152 | * hvc_console_setup() finds adapters. | |
153 | */ | |
154 | ||
4fa156ea AB |
155 | static void hvc_console_print(struct console *co, const char *b, |
156 | unsigned count) | |
837dcfaf | 157 | { |
45d607ed | 158 | char c[N_OUTBUF] __ALIGNED__; |
837dcfaf | 159 | unsigned i = 0, n = 0; |
030ffad2 | 160 | int r, donecr = 0, index = co->index; |
837dcfaf MM |
161 | |
162 | /* Console access attempt outside of acceptable console range. */ | |
030ffad2 | 163 | if (index >= MAX_NR_HVC_CONSOLES) |
837dcfaf MM |
164 | return; |
165 | ||
c3ea6921 | 166 | /* This console adapter was removed so it is not usable. */ |
030ffad2 | 167 | if (vtermnos[index] < 0) |
837dcfaf MM |
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 { | |
030ffad2 | 181 | r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
837dcfaf MM |
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 | { | |
7805b1b2 MM |
196 | if (vtermnos[c->index] == -1) |
197 | return NULL; | |
198 | ||
837dcfaf MM |
199 | *index = c->index; |
200 | return hvc_driver; | |
201 | } | |
202 | ||
203 | static int __init hvc_console_setup(struct console *co, char *options) | |
204 | { | |
7805b1b2 MM |
205 | if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
206 | return -ENODEV; | |
207 | ||
208 | if (vtermnos[co->index] == -1) | |
209 | return -ENODEV; | |
210 | ||
837dcfaf MM |
211 | return 0; |
212 | } | |
213 | ||
4fa156ea | 214 | static struct console hvc_con_driver = { |
837dcfaf MM |
215 | .name = "hvc", |
216 | .write = hvc_console_print, | |
217 | .device = hvc_console_device, | |
218 | .setup = hvc_console_setup, | |
219 | .flags = CON_PRINTBUFFER, | |
220 | .index = -1, | |
221 | }; | |
222 | ||
d5ee257c | 223 | /* |
c3ea6921 | 224 | * Early console initialization. Precedes driver initialization. |
d5ee257c MM |
225 | * |
226 | * (1) we are first, and the user specified another driver | |
227 | * -- index will remain -1 | |
228 | * (2) we are first and the user specified no driver | |
229 | * -- index will be set to 0, then we will fail setup. | |
230 | * (3) we are first and the user specified our driver | |
231 | * -- index will be set to user specified driver, and we will fail | |
232 | * (4) we are after driver, and this initcall will register us | |
233 | * -- if the user didn't specify a driver then the console will match | |
234 | * | |
235 | * Note that for cases 2 and 3, we will match later when the io driver | |
236 | * calls hvc_instantiate() and call register again. | |
237 | */ | |
837dcfaf MM |
238 | static int __init hvc_console_init(void) |
239 | { | |
837dcfaf MM |
240 | register_console(&hvc_con_driver); |
241 | return 0; | |
242 | } | |
243 | console_initcall(hvc_console_init); | |
1da177e4 | 244 | |
12b20ded GKH |
245 | /* callback when the kboject ref count reaches zero. */ |
246 | static void destroy_hvc_struct(struct kref *kref) | |
247 | { | |
248 | struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref); | |
249 | unsigned long flags; | |
250 | ||
251 | spin_lock(&hvc_structs_lock); | |
252 | ||
253 | spin_lock_irqsave(&hp->lock, flags); | |
254 | list_del(&(hp->next)); | |
255 | spin_unlock_irqrestore(&hp->lock, flags); | |
256 | ||
257 | spin_unlock(&hvc_structs_lock); | |
258 | ||
259 | kfree(hp); | |
260 | } | |
261 | ||
1da177e4 | 262 | /* |
6f24808e MM |
263 | * hvc_instantiate() is an early console discovery method which locates |
264 | * consoles * prior to the vio subsystem discovering them. Hotplugged | |
265 | * vty adapters do NOT get an hvc_instantiate() callback since they | |
266 | * appear after early console init. | |
1da177e4 | 267 | */ |
030ffad2 | 268 | int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops) |
837dcfaf | 269 | { |
7805b1b2 MM |
270 | struct hvc_struct *hp; |
271 | ||
837dcfaf MM |
272 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
273 | return -1; | |
1da177e4 | 274 | |
837dcfaf MM |
275 | if (vtermnos[index] != -1) |
276 | return -1; | |
277 | ||
c3ea6921 | 278 | /* make sure no no tty has been registered in this index */ |
7805b1b2 MM |
279 | hp = hvc_get_by_index(index); |
280 | if (hp) { | |
12b20ded | 281 | kref_put(&hp->kref, destroy_hvc_struct); |
7805b1b2 MM |
282 | return -1; |
283 | } | |
284 | ||
837dcfaf | 285 | vtermnos[index] = vtermno; |
030ffad2 | 286 | cons_ops[index] = ops; |
6f24808e | 287 | |
c3ea6921 | 288 | /* reserve all indices up to and including this index */ |
6f24808e MM |
289 | if (last_hvc < index) |
290 | last_hvc = index; | |
291 | ||
d5ee257c MM |
292 | /* if this index is what the user requested, then register |
293 | * now (setup won't fail at this point). It's ok to just | |
294 | * call register again if previously .setup failed. | |
295 | */ | |
296 | if (index == hvc_con_driver.index) | |
297 | register_console(&hvc_con_driver); | |
298 | ||
837dcfaf MM |
299 | return 0; |
300 | } | |
1da177e4 LT |
301 | |
302 | /* Wake the sleeping khvcd */ | |
303 | static void hvc_kick(void) | |
304 | { | |
305 | hvc_kicked = 1; | |
306 | wake_up_process(hvc_task); | |
307 | } | |
308 | ||
8b67f8c1 MM |
309 | static int hvc_poll(struct hvc_struct *hp); |
310 | ||
1da177e4 LT |
311 | /* |
312 | * NOTE: This API isn't used if the console adapter doesn't support interrupts. | |
313 | * In this case the console is poll driven. | |
314 | */ | |
7d12e780 | 315 | static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance) |
1da177e4 | 316 | { |
8b67f8c1 MM |
317 | /* if hvc_poll request a repoll, then kick the hvcd thread */ |
318 | if (hvc_poll(dev_instance)) | |
319 | hvc_kick(); | |
1da177e4 LT |
320 | return IRQ_HANDLED; |
321 | } | |
322 | ||
323 | static void hvc_unthrottle(struct tty_struct *tty) | |
324 | { | |
325 | hvc_kick(); | |
326 | } | |
327 | ||
1da177e4 LT |
328 | /* |
329 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
330 | * adapter to the kernel. | |
331 | */ | |
332 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
333 | { | |
334 | struct hvc_struct *hp; | |
335 | unsigned long flags; | |
8cd0ae05 | 336 | int irq = 0; |
1da177e4 | 337 | int rc = 0; |
1da177e4 | 338 | |
12b20ded | 339 | /* Auto increments kref reference if found. */ |
87fd7724 | 340 | if (!(hp = hvc_get_by_index(tty->index))) |
1da177e4 | 341 | return -ENODEV; |
1da177e4 LT |
342 | |
343 | spin_lock_irqsave(&hp->lock, flags); | |
344 | /* Check and then increment for fast path open. */ | |
345 | if (hp->count++ > 0) { | |
346 | spin_unlock_irqrestore(&hp->lock, flags); | |
347 | hvc_kick(); | |
348 | return 0; | |
349 | } /* else count == 0 */ | |
350 | ||
351 | tty->driver_data = hp; | |
fb5c594c MO |
352 | tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */ |
353 | ||
1da177e4 LT |
354 | hp->tty = tty; |
355 | /* Save for request_irq outside of spin_lock. */ | |
356 | irq = hp->irq; | |
8cd0ae05 | 357 | if (irq) |
1da177e4 LT |
358 | hp->irq_requested = 1; |
359 | ||
1da177e4 LT |
360 | spin_unlock_irqrestore(&hp->lock, flags); |
361 | /* check error, fallback to non-irq */ | |
8cd0ae05 | 362 | if (irq) |
0f2ed4c6 | 363 | rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED, "hvc_console", hp); |
1da177e4 LT |
364 | |
365 | /* | |
366 | * If the request_irq() fails and we return an error. The tty layer | |
367 | * will call hvc_close() after a failed open but we don't want to clean | |
368 | * up there so we'll clean up here and clear out the previously set | |
12b20ded | 369 | * tty fields and return the kref reference. |
1da177e4 LT |
370 | */ |
371 | if (rc) { | |
372 | spin_lock_irqsave(&hp->lock, flags); | |
373 | hp->tty = NULL; | |
374 | hp->irq_requested = 0; | |
375 | spin_unlock_irqrestore(&hp->lock, flags); | |
376 | tty->driver_data = NULL; | |
12b20ded | 377 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
378 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); |
379 | } | |
380 | /* Force wakeup of the polling thread */ | |
381 | hvc_kick(); | |
382 | ||
383 | return rc; | |
384 | } | |
385 | ||
386 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
387 | { | |
388 | struct hvc_struct *hp; | |
8cd0ae05 | 389 | int irq = 0; |
1da177e4 LT |
390 | unsigned long flags; |
391 | ||
392 | if (tty_hung_up_p(filp)) | |
393 | return; | |
394 | ||
395 | /* | |
396 | * No driver_data means that this close was issued after a failed | |
397 | * hvc_open by the tty layer's release_dev() function and we can just | |
12b20ded | 398 | * exit cleanly because the kref reference wasn't made. |
1da177e4 LT |
399 | */ |
400 | if (!tty->driver_data) | |
401 | return; | |
402 | ||
403 | hp = tty->driver_data; | |
404 | spin_lock_irqsave(&hp->lock, flags); | |
405 | ||
1da177e4 LT |
406 | if (--hp->count == 0) { |
407 | if (hp->irq_requested) | |
408 | irq = hp->irq; | |
409 | hp->irq_requested = 0; | |
410 | ||
411 | /* We are done with the tty pointer now. */ | |
412 | hp->tty = NULL; | |
413 | spin_unlock_irqrestore(&hp->lock, flags); | |
414 | ||
415 | /* | |
416 | * Chain calls chars_in_buffer() and returns immediately if | |
417 | * there is no buffered data otherwise sleeps on a wait queue | |
418 | * waking periodically to check chars_in_buffer(). | |
419 | */ | |
420 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); | |
421 | ||
8cd0ae05 | 422 | if (irq) |
1da177e4 LT |
423 | free_irq(irq, hp); |
424 | ||
425 | } else { | |
426 | if (hp->count < 0) | |
427 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", | |
428 | hp->vtermno, hp->count); | |
429 | spin_unlock_irqrestore(&hp->lock, flags); | |
430 | } | |
431 | ||
12b20ded | 432 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
433 | } |
434 | ||
435 | static void hvc_hangup(struct tty_struct *tty) | |
436 | { | |
437 | struct hvc_struct *hp = tty->driver_data; | |
438 | unsigned long flags; | |
8cd0ae05 | 439 | int irq = 0; |
1da177e4 | 440 | int temp_open_count; |
1da177e4 LT |
441 | |
442 | if (!hp) | |
443 | return; | |
444 | ||
445 | spin_lock_irqsave(&hp->lock, flags); | |
446 | ||
447 | /* | |
448 | * The N_TTY line discipline has problems such that in a close vs | |
449 | * open->hangup case this can be called after the final close so prevent | |
450 | * that from happening for now. | |
451 | */ | |
452 | if (hp->count <= 0) { | |
453 | spin_unlock_irqrestore(&hp->lock, flags); | |
454 | return; | |
455 | } | |
456 | ||
1da177e4 LT |
457 | temp_open_count = hp->count; |
458 | hp->count = 0; | |
459 | hp->n_outbuf = 0; | |
460 | hp->tty = NULL; | |
461 | if (hp->irq_requested) | |
462 | /* Saved for use outside of spin_lock. */ | |
463 | irq = hp->irq; | |
464 | hp->irq_requested = 0; | |
465 | spin_unlock_irqrestore(&hp->lock, flags); | |
8cd0ae05 | 466 | if (irq) |
1da177e4 LT |
467 | free_irq(irq, hp); |
468 | while(temp_open_count) { | |
469 | --temp_open_count; | |
12b20ded | 470 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
471 | } |
472 | } | |
473 | ||
474 | /* | |
475 | * Push buffered characters whether they were just recently buffered or waiting | |
476 | * on a blocked hypervisor. Call this function with hp->lock held. | |
477 | */ | |
478 | static void hvc_push(struct hvc_struct *hp) | |
479 | { | |
480 | int n; | |
481 | ||
030ffad2 | 482 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 483 | if (n <= 0) { |
45d607ed RA |
484 | if (n == 0) { |
485 | hp->do_wakeup = 1; | |
1da177e4 | 486 | return; |
45d607ed | 487 | } |
1da177e4 LT |
488 | /* throw away output on error; this happens when |
489 | there is no session connected to the vterm. */ | |
490 | hp->n_outbuf = 0; | |
491 | } else | |
492 | hp->n_outbuf -= n; | |
493 | if (hp->n_outbuf > 0) | |
494 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
495 | else | |
496 | hp->do_wakeup = 1; | |
497 | } | |
498 | ||
45d607ed | 499 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 500 | { |
45d607ed | 501 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
502 | unsigned long flags; |
503 | int rsize, written = 0; | |
504 | ||
45d607ed RA |
505 | /* This write was probably executed during a tty close. */ |
506 | if (!hp) | |
507 | return -EPIPE; | |
508 | ||
509 | if (hp->count <= 0) | |
510 | return -EIO; | |
511 | ||
1da177e4 LT |
512 | spin_lock_irqsave(&hp->lock, flags); |
513 | ||
514 | /* Push pending writes */ | |
515 | if (hp->n_outbuf > 0) | |
516 | hvc_push(hp); | |
517 | ||
4e9e95a3 | 518 | while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { |
1da177e4 LT |
519 | if (rsize > count) |
520 | rsize = count; | |
521 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
522 | count -= rsize; | |
523 | buf += rsize; | |
524 | hp->n_outbuf += rsize; | |
525 | written += rsize; | |
526 | hvc_push(hp); | |
527 | } | |
528 | spin_unlock_irqrestore(&hp->lock, flags); | |
529 | ||
1da177e4 LT |
530 | /* |
531 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
532 | */ |
533 | if (hp->n_outbuf) | |
534 | hvc_kick(); | |
535 | ||
536 | return written; | |
537 | } | |
538 | ||
539 | /* | |
540 | * This is actually a contract between the driver and the tty layer outlining | |
c3ea6921 | 541 | * how much write room the driver can guarantee will be sent OR BUFFERED. This |
1da177e4 LT |
542 | * driver MUST honor the return value. |
543 | */ | |
544 | static int hvc_write_room(struct tty_struct *tty) | |
545 | { | |
546 | struct hvc_struct *hp = tty->driver_data; | |
547 | ||
548 | if (!hp) | |
549 | return -1; | |
550 | ||
4e9e95a3 | 551 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
552 | } |
553 | ||
554 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
555 | { | |
556 | struct hvc_struct *hp = tty->driver_data; | |
557 | ||
558 | if (!hp) | |
559 | return -1; | |
560 | return hp->n_outbuf; | |
561 | } | |
562 | ||
b791072b WS |
563 | /* |
564 | * timeout will vary between the MIN and MAX values defined here. By default | |
565 | * and during console activity we will use a default MIN_TIMEOUT of 10. When | |
566 | * the console is idle, we increase the timeout value on each pass through | |
567 | * msleep until we reach the max. This may be noticeable as a brief (average | |
568 | * one second) delay on the console before the console responds to input when | |
569 | * there has been no input for some time. | |
570 | */ | |
571 | #define MIN_TIMEOUT (10) | |
572 | #define MAX_TIMEOUT (2000) | |
573 | static u32 timeout = MIN_TIMEOUT; | |
574 | ||
1da177e4 LT |
575 | #define HVC_POLL_READ 0x00000001 |
576 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 LT |
577 | |
578 | static int hvc_poll(struct hvc_struct *hp) | |
579 | { | |
580 | struct tty_struct *tty; | |
581 | int i, n, poll_mask = 0; | |
582 | char buf[N_INBUF] __ALIGNED__; | |
583 | unsigned long flags; | |
584 | int read_total = 0; | |
585 | ||
586 | spin_lock_irqsave(&hp->lock, flags); | |
587 | ||
588 | /* Push pending writes */ | |
589 | if (hp->n_outbuf > 0) | |
590 | hvc_push(hp); | |
b5374461 | 591 | |
1da177e4 LT |
592 | /* Reschedule us if still some write pending */ |
593 | if (hp->n_outbuf > 0) | |
594 | poll_mask |= HVC_POLL_WRITE; | |
595 | ||
596 | /* No tty attached, just skip */ | |
597 | tty = hp->tty; | |
598 | if (tty == NULL) | |
599 | goto bail; | |
600 | ||
601 | /* Now check if we can get data (are we throttled ?) */ | |
602 | if (test_bit(TTY_THROTTLED, &tty->flags)) | |
603 | goto throttled; | |
604 | ||
605 | /* If we aren't interrupt driven and aren't throttled, we always | |
606 | * request a reschedule | |
607 | */ | |
8cd0ae05 | 608 | if (hp->irq == 0) |
1da177e4 LT |
609 | poll_mask |= HVC_POLL_READ; |
610 | ||
611 | /* Read data if any */ | |
612 | for (;;) { | |
33f0f88f | 613 | int count = tty_buffer_request_room(tty, N_INBUF); |
1da177e4 LT |
614 | |
615 | /* If flip is full, just reschedule a later read */ | |
616 | if (count == 0) { | |
617 | poll_mask |= HVC_POLL_READ; | |
618 | break; | |
619 | } | |
620 | ||
030ffad2 | 621 | n = hp->ops->get_chars(hp->vtermno, buf, count); |
1da177e4 LT |
622 | if (n <= 0) { |
623 | /* Hangup the tty when disconnected from host */ | |
624 | if (n == -EPIPE) { | |
625 | spin_unlock_irqrestore(&hp->lock, flags); | |
626 | tty_hangup(tty); | |
627 | spin_lock_irqsave(&hp->lock, flags); | |
45d607ed RA |
628 | } else if ( n == -EAGAIN ) { |
629 | /* | |
630 | * Some back-ends can only ensure a certain min | |
631 | * num of bytes read, which may be > 'count'. | |
632 | * Let the tty clear the flip buff to make room. | |
633 | */ | |
634 | poll_mask |= HVC_POLL_READ; | |
1da177e4 LT |
635 | } |
636 | break; | |
637 | } | |
638 | for (i = 0; i < n; ++i) { | |
639 | #ifdef CONFIG_MAGIC_SYSRQ | |
2b9e0bac MM |
640 | if (hp->index == hvc_con_driver.index) { |
641 | /* Handle the SysRq Hack */ | |
642 | /* XXX should support a sequence */ | |
643 | if (buf[i] == '\x0f') { /* ^O */ | |
644 | sysrq_pressed = 1; | |
645 | continue; | |
646 | } else if (sysrq_pressed) { | |
7d12e780 | 647 | handle_sysrq(buf[i], tty); |
2b9e0bac MM |
648 | sysrq_pressed = 0; |
649 | continue; | |
650 | } | |
1da177e4 LT |
651 | } |
652 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
653 | tty_insert_flip_char(tty, buf[i], 0); | |
654 | } | |
655 | ||
1da177e4 | 656 | read_total += n; |
1da177e4 LT |
657 | } |
658 | throttled: | |
659 | /* Wakeup write queue if necessary */ | |
660 | if (hp->do_wakeup) { | |
661 | hp->do_wakeup = 0; | |
662 | tty_wakeup(tty); | |
663 | } | |
664 | bail: | |
665 | spin_unlock_irqrestore(&hp->lock, flags); | |
666 | ||
b791072b WS |
667 | if (read_total) { |
668 | /* Activity is occurring, so reset the polling backoff value to | |
669 | a minimum for performance. */ | |
670 | timeout = MIN_TIMEOUT; | |
671 | ||
fb5c594c | 672 | tty_flip_buffer_push(tty); |
b791072b WS |
673 | } |
674 | ||
1da177e4 LT |
675 | return poll_mask; |
676 | } | |
677 | ||
678 | #if defined(CONFIG_XMON) && defined(CONFIG_SMP) | |
679 | extern cpumask_t cpus_in_xmon; | |
680 | #else | |
681 | static const cpumask_t cpus_in_xmon = CPU_MASK_NONE; | |
682 | #endif | |
683 | ||
684 | /* | |
685 | * This kthread is either polling or interrupt driven. This is determined by | |
686 | * calling hvc_poll() who determines whether a console adapter support | |
687 | * interrupts. | |
688 | */ | |
5605d4de | 689 | static int khvcd(void *unused) |
1da177e4 LT |
690 | { |
691 | int poll_mask; | |
692 | struct hvc_struct *hp; | |
693 | ||
83144186 | 694 | set_freezable(); |
1da177e4 LT |
695 | __set_current_state(TASK_RUNNING); |
696 | do { | |
697 | poll_mask = 0; | |
698 | hvc_kicked = 0; | |
b64074e4 | 699 | try_to_freeze(); |
1da177e4 LT |
700 | wmb(); |
701 | if (cpus_empty(cpus_in_xmon)) { | |
702 | spin_lock(&hvc_structs_lock); | |
703 | list_for_each_entry(hp, &hvc_structs, next) { | |
1da177e4 LT |
704 | poll_mask |= hvc_poll(hp); |
705 | } | |
706 | spin_unlock(&hvc_structs_lock); | |
707 | } else | |
708 | poll_mask |= HVC_POLL_READ; | |
709 | if (hvc_kicked) | |
710 | continue; | |
b5374461 | 711 | if (poll_mask & HVC_POLL_WRITE) { |
1da177e4 LT |
712 | yield(); |
713 | continue; | |
714 | } | |
715 | set_current_state(TASK_INTERRUPTIBLE); | |
716 | if (!hvc_kicked) { | |
717 | if (poll_mask == 0) | |
718 | schedule(); | |
b791072b WS |
719 | else { |
720 | if (timeout < MAX_TIMEOUT) | |
721 | timeout += (timeout >> 6) + 1; | |
722 | ||
723 | msleep_interruptible(timeout); | |
724 | } | |
1da177e4 LT |
725 | } |
726 | __set_current_state(TASK_RUNNING); | |
727 | } while (!kthread_should_stop()); | |
728 | ||
729 | return 0; | |
730 | } | |
731 | ||
b68e31d0 | 732 | static const struct tty_operations hvc_ops = { |
1da177e4 LT |
733 | .open = hvc_open, |
734 | .close = hvc_close, | |
735 | .write = hvc_write, | |
736 | .hangup = hvc_hangup, | |
737 | .unthrottle = hvc_unthrottle, | |
738 | .write_room = hvc_write_room, | |
739 | .chars_in_buffer = hvc_chars_in_buffer, | |
740 | }; | |
741 | ||
030ffad2 | 742 | struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, |
4e9e95a3 | 743 | struct hv_ops *ops, int outbuf_size) |
1da177e4 LT |
744 | { |
745 | struct hvc_struct *hp; | |
6f24808e | 746 | int i; |
1da177e4 | 747 | |
3e6c6f63 RR |
748 | /* We wait until a driver actually comes along */ |
749 | if (!hvc_driver) { | |
750 | int err = hvc_init(); | |
751 | if (err) | |
752 | return ERR_PTR(err); | |
753 | } | |
754 | ||
4e9e95a3 SR |
755 | hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
756 | GFP_KERNEL); | |
1da177e4 | 757 | if (!hp) |
acad9559 | 758 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
759 | |
760 | memset(hp, 0x00, sizeof(*hp)); | |
acad9559 MM |
761 | |
762 | hp->vtermno = vtermno; | |
763 | hp->irq = irq; | |
030ffad2 | 764 | hp->ops = ops; |
4e9e95a3 SR |
765 | hp->outbuf_size = outbuf_size; |
766 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 | 767 | |
12b20ded | 768 | kref_init(&hp->kref); |
1da177e4 LT |
769 | |
770 | spin_lock_init(&hp->lock); | |
771 | spin_lock(&hvc_structs_lock); | |
6f24808e MM |
772 | |
773 | /* | |
774 | * find index to use: | |
775 | * see if this vterm id matches one registered for console. | |
776 | */ | |
777 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) | |
45d607ed RA |
778 | if (vtermnos[i] == hp->vtermno && |
779 | cons_ops[i] == hp->ops) | |
6f24808e MM |
780 | break; |
781 | ||
782 | /* no matching slot, just use a counter */ | |
783 | if (i >= MAX_NR_HVC_CONSOLES) | |
784 | i = ++last_hvc; | |
785 | ||
786 | hp->index = i; | |
787 | ||
1da177e4 LT |
788 | list_add_tail(&(hp->next), &hvc_structs); |
789 | spin_unlock(&hvc_structs_lock); | |
790 | ||
acad9559 | 791 | return hp; |
1da177e4 LT |
792 | } |
793 | ||
acad9559 | 794 | int __devexit hvc_remove(struct hvc_struct *hp) |
1da177e4 | 795 | { |
1da177e4 | 796 | unsigned long flags; |
1da177e4 LT |
797 | struct tty_struct *tty; |
798 | ||
799 | spin_lock_irqsave(&hp->lock, flags); | |
800 | tty = hp->tty; | |
1da177e4 LT |
801 | |
802 | if (hp->index < MAX_NR_HVC_CONSOLES) | |
803 | vtermnos[hp->index] = -1; | |
804 | ||
805 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
806 | ||
807 | spin_unlock_irqrestore(&hp->lock, flags); | |
808 | ||
809 | /* | |
12b20ded GKH |
810 | * We 'put' the instance that was grabbed when the kref instance |
811 | * was initialized using kref_init(). Let the last holder of this | |
812 | * kref cause it to be removed, which will probably be the tty_hangup | |
1da177e4 LT |
813 | * below. |
814 | */ | |
12b20ded | 815 | kref_put(&hp->kref, destroy_hvc_struct); |
1da177e4 LT |
816 | |
817 | /* | |
818 | * This function call will auto chain call hvc_hangup. The tty should | |
819 | * always be valid at this time unless a simultaneous tty close already | |
820 | * cleaned up the hvc_struct. | |
821 | */ | |
822 | if (tty) | |
823 | tty_hangup(tty); | |
824 | return 0; | |
825 | } | |
1da177e4 | 826 | |
3e6c6f63 RR |
827 | /* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
828 | static int hvc_init(void) | |
1da177e4 | 829 | { |
55aab8cd | 830 | struct tty_driver *drv; |
3e6c6f63 | 831 | int err; |
55aab8cd | 832 | |
5f6d9c07 | 833 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd | 834 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
3e6c6f63 RR |
835 | if (!drv) { |
836 | err = -ENOMEM; | |
837 | goto out; | |
838 | } | |
1da177e4 | 839 | |
55aab8cd | 840 | drv->owner = THIS_MODULE; |
55aab8cd MN |
841 | drv->driver_name = "hvc"; |
842 | drv->name = "hvc"; | |
843 | drv->major = HVC_MAJOR; | |
844 | drv->minor_start = HVC_MINOR; | |
845 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
846 | drv->init_termios = tty_std_termios; | |
847 | drv->flags = TTY_DRIVER_REAL_RAW; | |
848 | tty_set_operations(drv, &hvc_ops); | |
1da177e4 | 849 | |
1da177e4 LT |
850 | /* Always start the kthread because there can be hotplug vty adapters |
851 | * added later. */ | |
852 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
853 | if (IS_ERR(hvc_task)) { | |
3e6c6f63 RR |
854 | printk(KERN_ERR "Couldn't create kthread for console.\n"); |
855 | err = PTR_ERR(hvc_task); | |
856 | goto put_tty; | |
1da177e4 LT |
857 | } |
858 | ||
3e6c6f63 RR |
859 | err = tty_register_driver(drv); |
860 | if (err) { | |
861 | printk(KERN_ERR "Couldn't register hvc console driver\n"); | |
862 | goto stop_thread; | |
863 | } | |
ef4cbee0 | 864 | |
3e6c6f63 | 865 | /* FIXME: This mb() seems completely random. Remove it. */ |
55aab8cd MN |
866 | mb(); |
867 | hvc_driver = drv; | |
acad9559 | 868 | return 0; |
3e6c6f63 RR |
869 | |
870 | put_tty: | |
871 | put_tty_driver(hvc_driver); | |
872 | stop_thread: | |
873 | kthread_stop(hvc_task); | |
874 | hvc_task = NULL; | |
875 | out: | |
876 | return err; | |
1da177e4 LT |
877 | } |
878 | ||
c3ea6921 | 879 | /* This isn't particularly necessary due to this being a console driver |
320da0d2 MM |
880 | * but it is nice to be thorough. |
881 | */ | |
1da177e4 LT |
882 | static void __exit hvc_exit(void) |
883 | { | |
3e6c6f63 RR |
884 | if (hvc_driver) { |
885 | kthread_stop(hvc_task); | |
1da177e4 | 886 | |
3e6c6f63 RR |
887 | tty_unregister_driver(hvc_driver); |
888 | /* return tty_struct instances allocated in hvc_init(). */ | |
889 | put_tty_driver(hvc_driver); | |
890 | unregister_console(&hvc_con_driver); | |
891 | } | |
1da177e4 | 892 | } |
1da177e4 | 893 | module_exit(hvc_exit); |