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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
1da177e4 LT |
2 | /* |
3 | * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM | |
4 | * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM | |
5 | * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp. | |
6 | * Copyright (C) 2004 IBM Corporation | |
7 | * | |
8 | * Additional Author(s): | |
9 | * Ryan S. Arnold <rsa@us.ibm.com> | |
1da177e4 LT |
10 | */ |
11 | ||
12 | #include <linux/console.h> | |
13 | #include <linux/cpumask.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/kbd_kern.h> | |
16 | #include <linux/kernel.h> | |
1da177e4 LT |
17 | #include <linux/kthread.h> |
18 | #include <linux/list.h> | |
1da177e4 | 19 | #include <linux/major.h> |
f76a1cbe | 20 | #include <linux/atomic.h> |
1da177e4 LT |
21 | #include <linux/sysrq.h> |
22 | #include <linux/tty.h> | |
23 | #include <linux/tty_flip.h> | |
24 | #include <linux/sched.h> | |
25 | #include <linux/spinlock.h> | |
26 | #include <linux/delay.h> | |
7dfb7103 | 27 | #include <linux/freezer.h> |
5a0e3ad6 | 28 | #include <linux/slab.h> |
762e77ae | 29 | #include <linux/serial_core.h> |
45d607ed | 30 | |
7c0f6ba6 | 31 | #include <linux/uaccess.h> |
45d607ed RA |
32 | |
33 | #include "hvc_console.h" | |
1da177e4 LT |
34 | |
35 | #define HVC_MAJOR 229 | |
36 | #define HVC_MINOR 0 | |
37 | ||
1da177e4 LT |
38 | /* |
39 | * Wait this long per iteration while trying to push buffered data to the | |
40 | * hypervisor before allowing the tty to complete a close operation. | |
41 | */ | |
42 | #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ | |
43 | ||
44 | /* | |
45d607ed RA |
45 | * These sizes are most efficient for vio, because they are the |
46 | * native transfer size. We could make them selectable in the | |
47 | * future to better deal with backends that want other buffer sizes. | |
1da177e4 | 48 | */ |
1da177e4 LT |
49 | #define N_OUTBUF 16 |
50 | #define N_INBUF 16 | |
51 | ||
45d607ed | 52 | #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
1da177e4 | 53 | |
837dcfaf MM |
54 | static struct tty_driver *hvc_driver; |
55 | static struct task_struct *hvc_task; | |
56 | ||
57 | /* Picks up late kicks after list walk but before schedule() */ | |
58 | static int hvc_kicked; | |
59 | ||
f76a1cbe PG |
60 | /* hvc_init is triggered from hvc_alloc, i.e. only when actually used */ |
61 | static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1); | |
62 | ||
3e6c6f63 RR |
63 | static int hvc_init(void); |
64 | ||
837dcfaf MM |
65 | #ifdef CONFIG_MAGIC_SYSRQ |
66 | static int sysrq_pressed; | |
67 | #endif | |
68 | ||
1da177e4 | 69 | /* dynamic list of hvc_struct instances */ |
bed9759b | 70 | static LIST_HEAD(hvc_structs); |
1da177e4 LT |
71 | |
72 | /* | |
73 | * Protect the list of hvc_struct instances from inserts and removals during | |
74 | * list traversal. | |
75 | */ | |
a9bf5c8a | 76 | static DEFINE_MUTEX(hvc_structs_mutex); |
1da177e4 | 77 | |
837dcfaf | 78 | /* |
6f24808e MM |
79 | * This value is used to assign a tty->index value to a hvc_struct based |
80 | * upon order of exposure via hvc_probe(), when we can not match it to | |
c3ea6921 | 81 | * a console candidate registered with hvc_instantiate(). |
837dcfaf | 82 | */ |
6f24808e | 83 | static int last_hvc = -1; |
837dcfaf MM |
84 | |
85 | /* | |
a9bf5c8a | 86 | * Do not call this function with either the hvc_structs_mutex or the hvc_struct |
12b20ded | 87 | * lock held. If successful, this function increments the kref reference |
837dcfaf MM |
88 | * count against the target hvc_struct so it should be released when finished. |
89 | */ | |
4fa156ea | 90 | static struct hvc_struct *hvc_get_by_index(int index) |
837dcfaf MM |
91 | { |
92 | struct hvc_struct *hp; | |
93 | unsigned long flags; | |
94 | ||
a9bf5c8a | 95 | mutex_lock(&hvc_structs_mutex); |
837dcfaf MM |
96 | |
97 | list_for_each_entry(hp, &hvc_structs, next) { | |
98 | spin_lock_irqsave(&hp->lock, flags); | |
99 | if (hp->index == index) { | |
f3d9f250 | 100 | tty_port_get(&hp->port); |
837dcfaf | 101 | spin_unlock_irqrestore(&hp->lock, flags); |
a9bf5c8a | 102 | mutex_unlock(&hvc_structs_mutex); |
837dcfaf MM |
103 | return hp; |
104 | } | |
105 | spin_unlock_irqrestore(&hp->lock, flags); | |
106 | } | |
107 | hp = NULL; | |
a9bf5c8a | 108 | mutex_unlock(&hvc_structs_mutex); |
837dcfaf | 109 | |
837dcfaf MM |
110 | return hp; |
111 | } | |
112 | ||
9f65b81f NP |
113 | static int __hvc_flush(const struct hv_ops *ops, uint32_t vtermno, bool wait) |
114 | { | |
115 | if (wait) | |
116 | might_sleep(); | |
117 | ||
118 | if (ops->flush) | |
119 | return ops->flush(vtermno, wait); | |
120 | return 0; | |
121 | } | |
122 | ||
123 | static int hvc_console_flush(const struct hv_ops *ops, uint32_t vtermno) | |
124 | { | |
125 | return __hvc_flush(ops, vtermno, false); | |
126 | } | |
127 | ||
128 | /* | |
129 | * Wait for the console to flush before writing more to it. This sleeps. | |
130 | */ | |
131 | static int hvc_flush(struct hvc_struct *hp) | |
132 | { | |
133 | return __hvc_flush(hp->ops, hp->vtermno, true); | |
134 | } | |
135 | ||
1da177e4 LT |
136 | /* |
137 | * Initial console vtermnos for console API usage prior to full console | |
138 | * initialization. Any vty adapter outside this range will not have usable | |
139 | * console interfaces but can still be used as a tty device. This has to be | |
140 | * static because kmalloc will not work during early console init. | |
141 | */ | |
b5113068 | 142 | static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
64e4da57 MM |
143 | static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
144 | {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; | |
1da177e4 | 145 | |
837dcfaf MM |
146 | /* |
147 | * Console APIs, NOT TTY. These APIs are available immediately when | |
148 | * hvc_console_setup() finds adapters. | |
149 | */ | |
150 | ||
4fa156ea AB |
151 | static void hvc_console_print(struct console *co, const char *b, |
152 | unsigned count) | |
837dcfaf | 153 | { |
45d607ed | 154 | char c[N_OUTBUF] __ALIGNED__; |
837dcfaf | 155 | unsigned i = 0, n = 0; |
030ffad2 | 156 | int r, donecr = 0, index = co->index; |
837dcfaf MM |
157 | |
158 | /* Console access attempt outside of acceptable console range. */ | |
030ffad2 | 159 | if (index >= MAX_NR_HVC_CONSOLES) |
837dcfaf MM |
160 | return; |
161 | ||
c3ea6921 | 162 | /* This console adapter was removed so it is not usable. */ |
ecfcbee7 | 163 | if (vtermnos[index] == -1) |
837dcfaf MM |
164 | return; |
165 | ||
166 | while (count > 0 || i > 0) { | |
167 | if (count > 0 && i < sizeof(c)) { | |
168 | if (b[n] == '\n' && !donecr) { | |
169 | c[i++] = '\r'; | |
170 | donecr = 1; | |
171 | } else { | |
172 | c[i++] = b[n++]; | |
173 | donecr = 0; | |
174 | --count; | |
175 | } | |
176 | } else { | |
030ffad2 | 177 | r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
3feebbb5 | 178 | if (r <= 0) { |
8c2381af HB |
179 | /* throw away characters on error |
180 | * but spin in case of -EAGAIN */ | |
9f65b81f | 181 | if (r != -EAGAIN) { |
8c2381af | 182 | i = 0; |
9f65b81f NP |
183 | } else { |
184 | hvc_console_flush(cons_ops[index], | |
185 | vtermnos[index]); | |
186 | } | |
837dcfaf MM |
187 | } else if (r > 0) { |
188 | i -= r; | |
189 | if (i > 0) | |
190 | memmove(c, c+r, i); | |
191 | } | |
192 | } | |
193 | } | |
9f65b81f | 194 | hvc_console_flush(cons_ops[index], vtermnos[index]); |
837dcfaf MM |
195 | } |
196 | ||
197 | static struct tty_driver *hvc_console_device(struct console *c, int *index) | |
198 | { | |
7805b1b2 MM |
199 | if (vtermnos[c->index] == -1) |
200 | return NULL; | |
201 | ||
837dcfaf MM |
202 | *index = c->index; |
203 | return hvc_driver; | |
204 | } | |
205 | ||
501fed45 | 206 | static int hvc_console_setup(struct console *co, char *options) |
4d2bb3f5 | 207 | { |
7805b1b2 MM |
208 | if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
209 | return -ENODEV; | |
210 | ||
211 | if (vtermnos[co->index] == -1) | |
212 | return -ENODEV; | |
213 | ||
837dcfaf MM |
214 | return 0; |
215 | } | |
216 | ||
4455b119 | 217 | static struct console hvc_console = { |
837dcfaf MM |
218 | .name = "hvc", |
219 | .write = hvc_console_print, | |
220 | .device = hvc_console_device, | |
221 | .setup = hvc_console_setup, | |
222 | .flags = CON_PRINTBUFFER, | |
223 | .index = -1, | |
224 | }; | |
225 | ||
d5ee257c | 226 | /* |
c3ea6921 | 227 | * Early console initialization. Precedes driver initialization. |
d5ee257c MM |
228 | * |
229 | * (1) we are first, and the user specified another driver | |
230 | * -- index will remain -1 | |
231 | * (2) we are first and the user specified no driver | |
232 | * -- index will be set to 0, then we will fail setup. | |
233 | * (3) we are first and the user specified our driver | |
234 | * -- index will be set to user specified driver, and we will fail | |
235 | * (4) we are after driver, and this initcall will register us | |
236 | * -- if the user didn't specify a driver then the console will match | |
237 | * | |
238 | * Note that for cases 2 and 3, we will match later when the io driver | |
239 | * calls hvc_instantiate() and call register again. | |
240 | */ | |
837dcfaf MM |
241 | static int __init hvc_console_init(void) |
242 | { | |
4455b119 | 243 | register_console(&hvc_console); |
837dcfaf MM |
244 | return 0; |
245 | } | |
246 | console_initcall(hvc_console_init); | |
1da177e4 | 247 | |
12b20ded | 248 | /* callback when the kboject ref count reaches zero. */ |
f3d9f250 | 249 | static void hvc_port_destruct(struct tty_port *port) |
12b20ded | 250 | { |
f3d9f250 | 251 | struct hvc_struct *hp = container_of(port, struct hvc_struct, port); |
12b20ded GKH |
252 | unsigned long flags; |
253 | ||
a9bf5c8a | 254 | mutex_lock(&hvc_structs_mutex); |
12b20ded GKH |
255 | |
256 | spin_lock_irqsave(&hp->lock, flags); | |
257 | list_del(&(hp->next)); | |
258 | spin_unlock_irqrestore(&hp->lock, flags); | |
259 | ||
a9bf5c8a | 260 | mutex_unlock(&hvc_structs_mutex); |
12b20ded GKH |
261 | |
262 | kfree(hp); | |
263 | } | |
264 | ||
92057a49 BH |
265 | static void hvc_check_console(int index) |
266 | { | |
267 | /* Already enabled, bail out */ | |
268 | if (hvc_console.flags & CON_ENABLED) | |
269 | return; | |
270 | ||
271 | /* If this index is what the user requested, then register | |
272 | * now (setup won't fail at this point). It's ok to just | |
273 | * call register again if previously .setup failed. | |
274 | */ | |
275 | if (index == hvc_console.index) | |
276 | register_console(&hvc_console); | |
277 | } | |
278 | ||
1da177e4 | 279 | /* |
6f24808e MM |
280 | * hvc_instantiate() is an early console discovery method which locates |
281 | * consoles * prior to the vio subsystem discovering them. Hotplugged | |
282 | * vty adapters do NOT get an hvc_instantiate() callback since they | |
283 | * appear after early console init. | |
1da177e4 | 284 | */ |
b5113068 | 285 | int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) |
837dcfaf | 286 | { |
7805b1b2 MM |
287 | struct hvc_struct *hp; |
288 | ||
837dcfaf MM |
289 | if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
290 | return -1; | |
1da177e4 | 291 | |
837dcfaf MM |
292 | if (vtermnos[index] != -1) |
293 | return -1; | |
294 | ||
c3ea6921 | 295 | /* make sure no no tty has been registered in this index */ |
7805b1b2 MM |
296 | hp = hvc_get_by_index(index); |
297 | if (hp) { | |
f3d9f250 | 298 | tty_port_put(&hp->port); |
7805b1b2 MM |
299 | return -1; |
300 | } | |
301 | ||
837dcfaf | 302 | vtermnos[index] = vtermno; |
030ffad2 | 303 | cons_ops[index] = ops; |
6f24808e | 304 | |
c3ea6921 | 305 | /* reserve all indices up to and including this index */ |
6f24808e MM |
306 | if (last_hvc < index) |
307 | last_hvc = index; | |
308 | ||
92057a49 BH |
309 | /* check if we need to re-register the kernel console */ |
310 | hvc_check_console(index); | |
d5ee257c | 311 | |
837dcfaf MM |
312 | return 0; |
313 | } | |
7721c494 | 314 | EXPORT_SYMBOL_GPL(hvc_instantiate); |
1da177e4 LT |
315 | |
316 | /* Wake the sleeping khvcd */ | |
611e097d | 317 | void hvc_kick(void) |
1da177e4 LT |
318 | { |
319 | hvc_kicked = 1; | |
320 | wake_up_process(hvc_task); | |
321 | } | |
7721c494 | 322 | EXPORT_SYMBOL_GPL(hvc_kick); |
1da177e4 | 323 | |
1da177e4 LT |
324 | static void hvc_unthrottle(struct tty_struct *tty) |
325 | { | |
326 | hvc_kick(); | |
327 | } | |
328 | ||
bdb498c2 JS |
329 | static int hvc_install(struct tty_driver *driver, struct tty_struct *tty) |
330 | { | |
331 | struct hvc_struct *hp; | |
332 | int rc; | |
333 | ||
334 | /* Auto increments kref reference if found. */ | |
b8dccc1b GKH |
335 | hp = hvc_get_by_index(tty->index); |
336 | if (!hp) | |
bdb498c2 JS |
337 | return -ENODEV; |
338 | ||
339 | tty->driver_data = hp; | |
340 | ||
341 | rc = tty_port_install(&hp->port, driver, tty); | |
342 | if (rc) | |
343 | tty_port_put(&hp->port); | |
344 | return rc; | |
345 | } | |
346 | ||
1da177e4 LT |
347 | /* |
348 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
349 | * adapter to the kernel. | |
350 | */ | |
351 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
352 | { | |
bdb498c2 | 353 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 | 354 | unsigned long flags; |
1da177e4 | 355 | int rc = 0; |
1da177e4 | 356 | |
0146b693 | 357 | spin_lock_irqsave(&hp->port.lock, flags); |
1da177e4 | 358 | /* Check and then increment for fast path open. */ |
0146b693 JS |
359 | if (hp->port.count++ > 0) { |
360 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
1da177e4 LT |
361 | hvc_kick(); |
362 | return 0; | |
363 | } /* else count == 0 */ | |
0146b693 | 364 | spin_unlock_irqrestore(&hp->port.lock, flags); |
1da177e4 | 365 | |
85bbc003 JS |
366 | tty_port_tty_set(&hp->port, tty); |
367 | ||
b1b135c8 CB |
368 | if (hp->ops->notifier_add) |
369 | rc = hp->ops->notifier_add(hp, hp->data); | |
1da177e4 LT |
370 | |
371 | /* | |
611e097d | 372 | * If the notifier fails we return an error. The tty layer |
1da177e4 LT |
373 | * will call hvc_close() after a failed open but we don't want to clean |
374 | * up there so we'll clean up here and clear out the previously set | |
12b20ded | 375 | * tty fields and return the kref reference. |
1da177e4 LT |
376 | */ |
377 | if (rc) { | |
85bbc003 | 378 | tty_port_tty_set(&hp->port, NULL); |
1da177e4 | 379 | tty->driver_data = NULL; |
f3d9f250 | 380 | tty_port_put(&hp->port); |
1da177e4 | 381 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); |
33e745a1 HB |
382 | } else |
383 | /* We are ready... raise DTR/RTS */ | |
384 | if (C_BAUD(tty)) | |
385 | if (hp->ops->dtr_rts) | |
386 | hp->ops->dtr_rts(hp, 1); | |
387 | ||
1da177e4 LT |
388 | /* Force wakeup of the polling thread */ |
389 | hvc_kick(); | |
390 | ||
391 | return rc; | |
392 | } | |
393 | ||
394 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
395 | { | |
396 | struct hvc_struct *hp; | |
1da177e4 LT |
397 | unsigned long flags; |
398 | ||
399 | if (tty_hung_up_p(filp)) | |
400 | return; | |
401 | ||
402 | /* | |
403 | * No driver_data means that this close was issued after a failed | |
404 | * hvc_open by the tty layer's release_dev() function and we can just | |
12b20ded | 405 | * exit cleanly because the kref reference wasn't made. |
1da177e4 LT |
406 | */ |
407 | if (!tty->driver_data) | |
408 | return; | |
409 | ||
410 | hp = tty->driver_data; | |
e74d098c | 411 | |
0146b693 | 412 | spin_lock_irqsave(&hp->port.lock, flags); |
1da177e4 | 413 | |
0146b693 JS |
414 | if (--hp->port.count == 0) { |
415 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
85bbc003 JS |
416 | /* We are done with the tty pointer now. */ |
417 | tty_port_tty_set(&hp->port, NULL); | |
1da177e4 | 418 | |
33e745a1 HB |
419 | if (C_HUPCL(tty)) |
420 | if (hp->ops->dtr_rts) | |
421 | hp->ops->dtr_rts(hp, 0); | |
422 | ||
eef2622a CB |
423 | if (hp->ops->notifier_del) |
424 | hp->ops->notifier_del(hp, hp->data); | |
425 | ||
febde371 HB |
426 | /* cancel pending tty resize work */ |
427 | cancel_work_sync(&hp->tty_resize); | |
428 | ||
1da177e4 LT |
429 | /* |
430 | * Chain calls chars_in_buffer() and returns immediately if | |
431 | * there is no buffered data otherwise sleeps on a wait queue | |
432 | * waking periodically to check chars_in_buffer(). | |
433 | */ | |
79c1faa4 | 434 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); |
1da177e4 | 435 | } else { |
0146b693 | 436 | if (hp->port.count < 0) |
1da177e4 | 437 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", |
0146b693 JS |
438 | hp->vtermno, hp->port.count); |
439 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
1da177e4 | 440 | } |
bdb498c2 JS |
441 | } |
442 | ||
443 | static void hvc_cleanup(struct tty_struct *tty) | |
444 | { | |
445 | struct hvc_struct *hp = tty->driver_data; | |
1da177e4 | 446 | |
f3d9f250 | 447 | tty_port_put(&hp->port); |
1da177e4 LT |
448 | } |
449 | ||
450 | static void hvc_hangup(struct tty_struct *tty) | |
451 | { | |
452 | struct hvc_struct *hp = tty->driver_data; | |
453 | unsigned long flags; | |
1da177e4 LT |
454 | |
455 | if (!hp) | |
456 | return; | |
457 | ||
febde371 HB |
458 | /* cancel pending tty resize work */ |
459 | cancel_work_sync(&hp->tty_resize); | |
460 | ||
0146b693 | 461 | spin_lock_irqsave(&hp->port.lock, flags); |
1da177e4 LT |
462 | |
463 | /* | |
464 | * The N_TTY line discipline has problems such that in a close vs | |
465 | * open->hangup case this can be called after the final close so prevent | |
466 | * that from happening for now. | |
467 | */ | |
0146b693 JS |
468 | if (hp->port.count <= 0) { |
469 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
1da177e4 LT |
470 | return; |
471 | } | |
472 | ||
0146b693 JS |
473 | hp->port.count = 0; |
474 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
85bbc003 | 475 | tty_port_tty_set(&hp->port, NULL); |
eef2622a | 476 | |
0146b693 JS |
477 | hp->n_outbuf = 0; |
478 | ||
fc362e2e | 479 | if (hp->ops->notifier_hangup) |
e74d098c | 480 | hp->ops->notifier_hangup(hp, hp->data); |
1da177e4 LT |
481 | } |
482 | ||
483 | /* | |
484 | * Push buffered characters whether they were just recently buffered or waiting | |
485 | * on a blocked hypervisor. Call this function with hp->lock held. | |
486 | */ | |
3feebbb5 | 487 | static int hvc_push(struct hvc_struct *hp) |
1da177e4 LT |
488 | { |
489 | int n; | |
490 | ||
030ffad2 | 491 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 492 | if (n <= 0) { |
8c2381af | 493 | if (n == 0 || n == -EAGAIN) { |
45d607ed | 494 | hp->do_wakeup = 1; |
3feebbb5 | 495 | return 0; |
45d607ed | 496 | } |
1da177e4 LT |
497 | /* throw away output on error; this happens when |
498 | there is no session connected to the vterm. */ | |
499 | hp->n_outbuf = 0; | |
500 | } else | |
501 | hp->n_outbuf -= n; | |
502 | if (hp->n_outbuf > 0) | |
503 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
504 | else | |
505 | hp->do_wakeup = 1; | |
3feebbb5 HB |
506 | |
507 | return n; | |
1da177e4 LT |
508 | } |
509 | ||
45d607ed | 510 | static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
1da177e4 | 511 | { |
45d607ed | 512 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
513 | unsigned long flags; |
514 | int rsize, written = 0; | |
515 | ||
45d607ed RA |
516 | /* This write was probably executed during a tty close. */ |
517 | if (!hp) | |
518 | return -EPIPE; | |
519 | ||
0146b693 JS |
520 | /* FIXME what's this (unprotected) check for? */ |
521 | if (hp->port.count <= 0) | |
45d607ed RA |
522 | return -EIO; |
523 | ||
550ddadc | 524 | while (count > 0) { |
7f2bf784 NP |
525 | int ret = 0; |
526 | ||
550ddadc | 527 | spin_lock_irqsave(&hp->lock, flags); |
1da177e4 | 528 | |
550ddadc NP |
529 | rsize = hp->outbuf_size - hp->n_outbuf; |
530 | ||
531 | if (rsize) { | |
532 | if (rsize > count) | |
533 | rsize = count; | |
534 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
535 | count -= rsize; | |
536 | buf += rsize; | |
537 | hp->n_outbuf += rsize; | |
538 | written += rsize; | |
539 | } | |
540 | ||
541 | if (hp->n_outbuf > 0) | |
7f2bf784 | 542 | ret = hvc_push(hp); |
550ddadc NP |
543 | |
544 | spin_unlock_irqrestore(&hp->lock, flags); | |
545 | ||
7f2bf784 NP |
546 | if (!ret) |
547 | break; | |
548 | ||
9f65b81f NP |
549 | if (count) { |
550 | if (hp->n_outbuf > 0) | |
551 | hvc_flush(hp); | |
550ddadc | 552 | cond_resched(); |
9f65b81f | 553 | } |
1da177e4 | 554 | } |
1da177e4 | 555 | |
1da177e4 LT |
556 | /* |
557 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
558 | */ |
559 | if (hp->n_outbuf) | |
560 | hvc_kick(); | |
561 | ||
562 | return written; | |
563 | } | |
564 | ||
febde371 HB |
565 | /** |
566 | * hvc_set_winsz() - Resize the hvc tty terminal window. | |
567 | * @work: work structure. | |
568 | * | |
569 | * The routine shall not be called within an atomic context because it | |
570 | * might sleep. | |
571 | * | |
572 | * Locking: hp->lock | |
573 | */ | |
574 | static void hvc_set_winsz(struct work_struct *work) | |
575 | { | |
576 | struct hvc_struct *hp; | |
577 | unsigned long hvc_flags; | |
578 | struct tty_struct *tty; | |
579 | struct winsize ws; | |
580 | ||
581 | hp = container_of(work, struct hvc_struct, tty_resize); | |
febde371 | 582 | |
85bbc003 JS |
583 | tty = tty_port_tty_get(&hp->port); |
584 | if (!tty) | |
febde371 | 585 | return; |
85bbc003 JS |
586 | |
587 | spin_lock_irqsave(&hp->lock, hvc_flags); | |
588 | ws = hp->ws; | |
febde371 HB |
589 | spin_unlock_irqrestore(&hp->lock, hvc_flags); |
590 | ||
fc6f6238 | 591 | tty_do_resize(tty, &ws); |
febde371 HB |
592 | tty_kref_put(tty); |
593 | } | |
594 | ||
1da177e4 LT |
595 | /* |
596 | * This is actually a contract between the driver and the tty layer outlining | |
c3ea6921 | 597 | * how much write room the driver can guarantee will be sent OR BUFFERED. This |
1da177e4 LT |
598 | * driver MUST honor the return value. |
599 | */ | |
600 | static int hvc_write_room(struct tty_struct *tty) | |
601 | { | |
602 | struct hvc_struct *hp = tty->driver_data; | |
603 | ||
604 | if (!hp) | |
d83114e9 | 605 | return 0; |
1da177e4 | 606 | |
4e9e95a3 | 607 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
608 | } |
609 | ||
610 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
611 | { | |
612 | struct hvc_struct *hp = tty->driver_data; | |
613 | ||
614 | if (!hp) | |
23198fda | 615 | return 0; |
1da177e4 LT |
616 | return hp->n_outbuf; |
617 | } | |
618 | ||
b791072b WS |
619 | /* |
620 | * timeout will vary between the MIN and MAX values defined here. By default | |
621 | * and during console activity we will use a default MIN_TIMEOUT of 10. When | |
622 | * the console is idle, we increase the timeout value on each pass through | |
623 | * msleep until we reach the max. This may be noticeable as a brief (average | |
624 | * one second) delay on the console before the console responds to input when | |
625 | * there has been no input for some time. | |
626 | */ | |
627 | #define MIN_TIMEOUT (10) | |
628 | #define MAX_TIMEOUT (2000) | |
629 | static u32 timeout = MIN_TIMEOUT; | |
630 | ||
68b2fc71 NP |
631 | /* |
632 | * Maximum number of bytes to get from the console driver if hvc_poll is | |
633 | * called from driver (and can't sleep). Any more than this and we break | |
634 | * and start polling with khvcd. This value was derived from from an OpenBMC | |
635 | * console with the OPAL driver that results in about 0.25ms interrupts off | |
636 | * latency. | |
637 | */ | |
638 | #define HVC_ATOMIC_READ_MAX 128 | |
639 | ||
1da177e4 LT |
640 | #define HVC_POLL_READ 0x00000001 |
641 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 | 642 | |
cfb5946b | 643 | static int __hvc_poll(struct hvc_struct *hp, bool may_sleep) |
1da177e4 LT |
644 | { |
645 | struct tty_struct *tty; | |
ec97eaad | 646 | int i, n, count, poll_mask = 0; |
1da177e4 LT |
647 | char buf[N_INBUF] __ALIGNED__; |
648 | unsigned long flags; | |
649 | int read_total = 0; | |
3feebbb5 | 650 | int written_total = 0; |
1da177e4 LT |
651 | |
652 | spin_lock_irqsave(&hp->lock, flags); | |
653 | ||
654 | /* Push pending writes */ | |
655 | if (hp->n_outbuf > 0) | |
3feebbb5 | 656 | written_total = hvc_push(hp); |
b5374461 | 657 | |
1da177e4 | 658 | /* Reschedule us if still some write pending */ |
3feebbb5 | 659 | if (hp->n_outbuf > 0) { |
1da177e4 | 660 | poll_mask |= HVC_POLL_WRITE; |
3feebbb5 HB |
661 | /* If hvc_push() was not able to write, sleep a few msecs */ |
662 | timeout = (written_total) ? 0 : MIN_TIMEOUT; | |
663 | } | |
1da177e4 | 664 | |
cfb5946b NP |
665 | if (may_sleep) { |
666 | spin_unlock_irqrestore(&hp->lock, flags); | |
667 | cond_resched(); | |
668 | spin_lock_irqsave(&hp->lock, flags); | |
669 | } | |
670 | ||
1da177e4 | 671 | /* No tty attached, just skip */ |
85bbc003 | 672 | tty = tty_port_tty_get(&hp->port); |
1da177e4 LT |
673 | if (tty == NULL) |
674 | goto bail; | |
675 | ||
676 | /* Now check if we can get data (are we throttled ?) */ | |
97ef38b8 | 677 | if (tty_throttled(tty)) |
ec97eaad | 678 | goto out; |
1da177e4 | 679 | |
611e097d | 680 | /* If we aren't notifier driven and aren't throttled, we always |
1da177e4 LT |
681 | * request a reschedule |
682 | */ | |
611e097d | 683 | if (!hp->irq_requested) |
1da177e4 LT |
684 | poll_mask |= HVC_POLL_READ; |
685 | ||
68b2fc71 | 686 | read_again: |
1da177e4 | 687 | /* Read data if any */ |
ec97eaad NP |
688 | count = tty_buffer_request_room(&hp->port, N_INBUF); |
689 | ||
690 | /* If flip is full, just reschedule a later read */ | |
691 | if (count == 0) { | |
692 | poll_mask |= HVC_POLL_READ; | |
693 | goto out; | |
694 | } | |
695 | ||
696 | n = hp->ops->get_chars(hp->vtermno, buf, count); | |
697 | if (n <= 0) { | |
698 | /* Hangup the tty when disconnected from host */ | |
699 | if (n == -EPIPE) { | |
700 | spin_unlock_irqrestore(&hp->lock, flags); | |
701 | tty_hangup(tty); | |
702 | spin_lock_irqsave(&hp->lock, flags); | |
703 | } else if ( n == -EAGAIN ) { | |
704 | /* | |
705 | * Some back-ends can only ensure a certain min | |
706 | * num of bytes read, which may be > 'count'. | |
707 | * Let the tty clear the flip buff to make room. | |
708 | */ | |
1da177e4 | 709 | poll_mask |= HVC_POLL_READ; |
1da177e4 | 710 | } |
ec97eaad NP |
711 | goto out; |
712 | } | |
1da177e4 | 713 | |
ec97eaad | 714 | for (i = 0; i < n; ++i) { |
1da177e4 | 715 | #ifdef CONFIG_MAGIC_SYSRQ |
ec97eaad NP |
716 | if (hp->index == hvc_console.index) { |
717 | /* Handle the SysRq Hack */ | |
718 | /* XXX should support a sequence */ | |
719 | if (buf[i] == '\x0f') { /* ^O */ | |
720 | /* if ^O is pressed again, reset | |
721 | * sysrq_pressed and flip ^O char */ | |
722 | sysrq_pressed = !sysrq_pressed; | |
723 | if (sysrq_pressed) | |
2b9e0bac | 724 | continue; |
ec97eaad NP |
725 | } else if (sysrq_pressed) { |
726 | handle_sysrq(buf[i]); | |
727 | sysrq_pressed = 0; | |
728 | continue; | |
1da177e4 | 729 | } |
1da177e4 | 730 | } |
ec97eaad NP |
731 | #endif /* CONFIG_MAGIC_SYSRQ */ |
732 | tty_insert_flip_char(&hp->port, buf[i], 0); | |
1da177e4 | 733 | } |
68b2fc71 NP |
734 | read_total += n; |
735 | ||
736 | if (may_sleep) { | |
737 | /* Keep going until the flip is full */ | |
738 | spin_unlock_irqrestore(&hp->lock, flags); | |
739 | cond_resched(); | |
740 | spin_lock_irqsave(&hp->lock, flags); | |
741 | goto read_again; | |
742 | } else if (read_total < HVC_ATOMIC_READ_MAX) { | |
743 | /* Break and defer if it's a large read in atomic */ | |
744 | goto read_again; | |
745 | } | |
ec97eaad | 746 | |
6e7f6b82 NP |
747 | /* |
748 | * Latency break, schedule another poll immediately. | |
749 | */ | |
750 | poll_mask |= HVC_POLL_READ; | |
751 | ||
ec97eaad | 752 | out: |
1da177e4 LT |
753 | /* Wakeup write queue if necessary */ |
754 | if (hp->do_wakeup) { | |
755 | hp->do_wakeup = 0; | |
756 | tty_wakeup(tty); | |
757 | } | |
758 | bail: | |
759 | spin_unlock_irqrestore(&hp->lock, flags); | |
760 | ||
b791072b WS |
761 | if (read_total) { |
762 | /* Activity is occurring, so reset the polling backoff value to | |
763 | a minimum for performance. */ | |
764 | timeout = MIN_TIMEOUT; | |
765 | ||
2e124b4a | 766 | tty_flip_buffer_push(&hp->port); |
b791072b | 767 | } |
85bbc003 | 768 | tty_kref_put(tty); |
b791072b | 769 | |
1da177e4 LT |
770 | return poll_mask; |
771 | } | |
cfb5946b NP |
772 | |
773 | int hvc_poll(struct hvc_struct *hp) | |
774 | { | |
775 | return __hvc_poll(hp, false); | |
776 | } | |
7721c494 | 777 | EXPORT_SYMBOL_GPL(hvc_poll); |
1da177e4 | 778 | |
febde371 | 779 | /** |
254be490 | 780 | * __hvc_resize() - Update terminal window size information. |
febde371 HB |
781 | * @hp: HVC console pointer |
782 | * @ws: Terminal window size structure | |
783 | * | |
784 | * Stores the specified window size information in the hvc structure of @hp. | |
785 | * The function schedule the tty resize update. | |
786 | * | |
787 | * Locking: Locking free; the function MUST be called holding hp->lock | |
788 | */ | |
254be490 | 789 | void __hvc_resize(struct hvc_struct *hp, struct winsize ws) |
febde371 | 790 | { |
7947cf0d HB |
791 | hp->ws = ws; |
792 | schedule_work(&hp->tty_resize); | |
febde371 | 793 | } |
254be490 | 794 | EXPORT_SYMBOL_GPL(__hvc_resize); |
febde371 | 795 | |
1da177e4 LT |
796 | /* |
797 | * This kthread is either polling or interrupt driven. This is determined by | |
798 | * calling hvc_poll() who determines whether a console adapter support | |
799 | * interrupts. | |
800 | */ | |
5605d4de | 801 | static int khvcd(void *unused) |
1da177e4 LT |
802 | { |
803 | int poll_mask; | |
804 | struct hvc_struct *hp; | |
805 | ||
83144186 | 806 | set_freezable(); |
1da177e4 LT |
807 | do { |
808 | poll_mask = 0; | |
809 | hvc_kicked = 0; | |
b64074e4 | 810 | try_to_freeze(); |
1da177e4 | 811 | wmb(); |
1c8950ff | 812 | if (!cpus_are_in_xmon()) { |
a9bf5c8a | 813 | mutex_lock(&hvc_structs_mutex); |
1da177e4 | 814 | list_for_each_entry(hp, &hvc_structs, next) { |
cfb5946b NP |
815 | poll_mask |= __hvc_poll(hp, true); |
816 | cond_resched(); | |
1da177e4 | 817 | } |
a9bf5c8a | 818 | mutex_unlock(&hvc_structs_mutex); |
1da177e4 LT |
819 | } else |
820 | poll_mask |= HVC_POLL_READ; | |
821 | if (hvc_kicked) | |
822 | continue; | |
1da177e4 LT |
823 | set_current_state(TASK_INTERRUPTIBLE); |
824 | if (!hvc_kicked) { | |
825 | if (poll_mask == 0) | |
826 | schedule(); | |
b791072b | 827 | else { |
15a27431 BH |
828 | unsigned long j_timeout; |
829 | ||
b791072b WS |
830 | if (timeout < MAX_TIMEOUT) |
831 | timeout += (timeout >> 6) + 1; | |
832 | ||
15a27431 BH |
833 | /* |
834 | * We don't use msleep_interruptible otherwise | |
835 | * "kick" will fail to wake us up | |
836 | */ | |
837 | j_timeout = msecs_to_jiffies(timeout) + 1; | |
838 | schedule_timeout_interruptible(j_timeout); | |
b791072b | 839 | } |
1da177e4 LT |
840 | } |
841 | __set_current_state(TASK_RUNNING); | |
842 | } while (!kthread_should_stop()); | |
843 | ||
844 | return 0; | |
845 | } | |
846 | ||
4d2bb3f5 BH |
847 | static int hvc_tiocmget(struct tty_struct *tty) |
848 | { | |
849 | struct hvc_struct *hp = tty->driver_data; | |
850 | ||
851 | if (!hp || !hp->ops->tiocmget) | |
852 | return -EINVAL; | |
853 | return hp->ops->tiocmget(hp); | |
854 | } | |
855 | ||
856 | static int hvc_tiocmset(struct tty_struct *tty, | |
857 | unsigned int set, unsigned int clear) | |
858 | { | |
859 | struct hvc_struct *hp = tty->driver_data; | |
860 | ||
861 | if (!hp || !hp->ops->tiocmset) | |
862 | return -EINVAL; | |
863 | return hp->ops->tiocmset(hp, set, clear); | |
864 | } | |
865 | ||
762e77ae | 866 | #ifdef CONFIG_CONSOLE_POLL |
5855b210 | 867 | static int hvc_poll_init(struct tty_driver *driver, int line, char *options) |
762e77ae AB |
868 | { |
869 | return 0; | |
870 | } | |
871 | ||
872 | static int hvc_poll_get_char(struct tty_driver *driver, int line) | |
873 | { | |
874 | struct tty_struct *tty = driver->ttys[0]; | |
875 | struct hvc_struct *hp = tty->driver_data; | |
876 | int n; | |
877 | char ch; | |
878 | ||
879 | n = hp->ops->get_chars(hp->vtermno, &ch, 1); | |
880 | ||
fab794ae | 881 | if (n <= 0) |
762e77ae AB |
882 | return NO_POLL_CHAR; |
883 | ||
884 | return ch; | |
885 | } | |
886 | ||
887 | static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch) | |
888 | { | |
889 | struct tty_struct *tty = driver->ttys[0]; | |
890 | struct hvc_struct *hp = tty->driver_data; | |
891 | int n; | |
892 | ||
893 | do { | |
894 | n = hp->ops->put_chars(hp->vtermno, &ch, 1); | |
895 | } while (n <= 0); | |
896 | } | |
897 | #endif | |
898 | ||
b68e31d0 | 899 | static const struct tty_operations hvc_ops = { |
bdb498c2 | 900 | .install = hvc_install, |
1da177e4 LT |
901 | .open = hvc_open, |
902 | .close = hvc_close, | |
bdb498c2 | 903 | .cleanup = hvc_cleanup, |
1da177e4 LT |
904 | .write = hvc_write, |
905 | .hangup = hvc_hangup, | |
906 | .unthrottle = hvc_unthrottle, | |
907 | .write_room = hvc_write_room, | |
908 | .chars_in_buffer = hvc_chars_in_buffer, | |
4d2bb3f5 BH |
909 | .tiocmget = hvc_tiocmget, |
910 | .tiocmset = hvc_tiocmset, | |
762e77ae AB |
911 | #ifdef CONFIG_CONSOLE_POLL |
912 | .poll_init = hvc_poll_init, | |
913 | .poll_get_char = hvc_poll_get_char, | |
914 | .poll_put_char = hvc_poll_put_char, | |
915 | #endif | |
1da177e4 LT |
916 | }; |
917 | ||
f3d9f250 JS |
918 | static const struct tty_port_operations hvc_port_ops = { |
919 | .destruct = hvc_port_destruct, | |
920 | }; | |
921 | ||
119ea109 AS |
922 | struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, |
923 | const struct hv_ops *ops, | |
924 | int outbuf_size) | |
1da177e4 LT |
925 | { |
926 | struct hvc_struct *hp; | |
6f24808e | 927 | int i; |
1da177e4 | 928 | |
3e6c6f63 | 929 | /* We wait until a driver actually comes along */ |
f76a1cbe | 930 | if (atomic_inc_not_zero(&hvc_needs_init)) { |
3e6c6f63 RR |
931 | int err = hvc_init(); |
932 | if (err) | |
933 | return ERR_PTR(err); | |
934 | } | |
935 | ||
2da7582f | 936 | hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
4e9e95a3 | 937 | GFP_KERNEL); |
1da177e4 | 938 | if (!hp) |
acad9559 | 939 | return ERR_PTR(-ENOMEM); |
1da177e4 | 940 | |
acad9559 | 941 | hp->vtermno = vtermno; |
611e097d | 942 | hp->data = data; |
030ffad2 | 943 | hp->ops = ops; |
4e9e95a3 SR |
944 | hp->outbuf_size = outbuf_size; |
945 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 | 946 | |
f3d9f250 JS |
947 | tty_port_init(&hp->port); |
948 | hp->port.ops = &hvc_port_ops; | |
1da177e4 | 949 | |
febde371 | 950 | INIT_WORK(&hp->tty_resize, hvc_set_winsz); |
1da177e4 | 951 | spin_lock_init(&hp->lock); |
a9bf5c8a | 952 | mutex_lock(&hvc_structs_mutex); |
6f24808e MM |
953 | |
954 | /* | |
955 | * find index to use: | |
956 | * see if this vterm id matches one registered for console. | |
957 | */ | |
31555213 | 958 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) |
45d607ed RA |
959 | if (vtermnos[i] == hp->vtermno && |
960 | cons_ops[i] == hp->ops) | |
6f24808e MM |
961 | break; |
962 | ||
963 | /* no matching slot, just use a counter */ | |
964 | if (i >= MAX_NR_HVC_CONSOLES) | |
965 | i = ++last_hvc; | |
966 | ||
967 | hp->index = i; | |
92057a49 BH |
968 | cons_ops[i] = ops; |
969 | vtermnos[i] = vtermno; | |
6f24808e | 970 | |
1da177e4 | 971 | list_add_tail(&(hp->next), &hvc_structs); |
a9bf5c8a | 972 | mutex_unlock(&hvc_structs_mutex); |
1da177e4 | 973 | |
92057a49 BH |
974 | /* check if we need to re-register the kernel console */ |
975 | hvc_check_console(i); | |
976 | ||
acad9559 | 977 | return hp; |
1da177e4 | 978 | } |
7721c494 | 979 | EXPORT_SYMBOL_GPL(hvc_alloc); |
1da177e4 | 980 | |
934752d8 | 981 | int hvc_remove(struct hvc_struct *hp) |
1da177e4 | 982 | { |
1da177e4 | 983 | unsigned long flags; |
1da177e4 LT |
984 | struct tty_struct *tty; |
985 | ||
85bbc003 | 986 | tty = tty_port_tty_get(&hp->port); |
1da177e4 | 987 | |
19fa6e60 | 988 | console_lock(); |
85bbc003 | 989 | spin_lock_irqsave(&hp->lock, flags); |
92057a49 | 990 | if (hp->index < MAX_NR_HVC_CONSOLES) { |
1da177e4 | 991 | vtermnos[hp->index] = -1; |
92057a49 | 992 | cons_ops[hp->index] = NULL; |
92057a49 | 993 | } |
1da177e4 LT |
994 | |
995 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
996 | ||
997 | spin_unlock_irqrestore(&hp->lock, flags); | |
19fa6e60 | 998 | console_unlock(); |
1da177e4 LT |
999 | |
1000 | /* | |
12b20ded GKH |
1001 | * We 'put' the instance that was grabbed when the kref instance |
1002 | * was initialized using kref_init(). Let the last holder of this | |
e74d098c | 1003 | * kref cause it to be removed, which will probably be the tty_vhangup |
1da177e4 LT |
1004 | * below. |
1005 | */ | |
f3d9f250 | 1006 | tty_port_put(&hp->port); |
1da177e4 LT |
1007 | |
1008 | /* | |
e74d098c | 1009 | * This function call will auto chain call hvc_hangup. |
1da177e4 | 1010 | */ |
e74d098c AS |
1011 | if (tty) { |
1012 | tty_vhangup(tty); | |
1013 | tty_kref_put(tty); | |
1014 | } | |
1da177e4 LT |
1015 | return 0; |
1016 | } | |
c0cefebc | 1017 | EXPORT_SYMBOL_GPL(hvc_remove); |
1da177e4 | 1018 | |
3e6c6f63 RR |
1019 | /* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
1020 | static int hvc_init(void) | |
1da177e4 | 1021 | { |
55aab8cd | 1022 | struct tty_driver *drv; |
3e6c6f63 | 1023 | int err; |
55aab8cd | 1024 | |
5f6d9c07 | 1025 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd | 1026 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
3e6c6f63 RR |
1027 | if (!drv) { |
1028 | err = -ENOMEM; | |
1029 | goto out; | |
1030 | } | |
1da177e4 | 1031 | |
55aab8cd MN |
1032 | drv->driver_name = "hvc"; |
1033 | drv->name = "hvc"; | |
1034 | drv->major = HVC_MAJOR; | |
1035 | drv->minor_start = HVC_MINOR; | |
1036 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
1037 | drv->init_termios = tty_std_termios; | |
56ce9e2b | 1038 | drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; |
55aab8cd | 1039 | tty_set_operations(drv, &hvc_ops); |
1da177e4 | 1040 | |
1da177e4 LT |
1041 | /* Always start the kthread because there can be hotplug vty adapters |
1042 | * added later. */ | |
1043 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
1044 | if (IS_ERR(hvc_task)) { | |
3e6c6f63 RR |
1045 | printk(KERN_ERR "Couldn't create kthread for console.\n"); |
1046 | err = PTR_ERR(hvc_task); | |
1047 | goto put_tty; | |
1da177e4 LT |
1048 | } |
1049 | ||
3e6c6f63 RR |
1050 | err = tty_register_driver(drv); |
1051 | if (err) { | |
1052 | printk(KERN_ERR "Couldn't register hvc console driver\n"); | |
1053 | goto stop_thread; | |
1054 | } | |
ef4cbee0 | 1055 | |
9fef3d2d MM |
1056 | /* |
1057 | * Make sure tty is fully registered before allowing it to be | |
1058 | * found by hvc_console_device. | |
1059 | */ | |
1060 | smp_mb(); | |
55aab8cd | 1061 | hvc_driver = drv; |
acad9559 | 1062 | return 0; |
3e6c6f63 | 1063 | |
3e6c6f63 RR |
1064 | stop_thread: |
1065 | kthread_stop(hvc_task); | |
1066 | hvc_task = NULL; | |
2571cd6a JL |
1067 | put_tty: |
1068 | put_tty_driver(drv); | |
3e6c6f63 RR |
1069 | out: |
1070 | return err; | |
1da177e4 | 1071 | } |