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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 | |
92057a49 BH |
305 | /* check if we need to re-register the kernel console */ |
306 | hvc_check_console(index); | |
d5ee257c | 307 | |
837dcfaf MM |
308 | return 0; |
309 | } | |
7721c494 | 310 | EXPORT_SYMBOL_GPL(hvc_instantiate); |
1da177e4 LT |
311 | |
312 | /* Wake the sleeping khvcd */ | |
611e097d | 313 | void hvc_kick(void) |
1da177e4 LT |
314 | { |
315 | hvc_kicked = 1; | |
316 | wake_up_process(hvc_task); | |
317 | } | |
7721c494 | 318 | EXPORT_SYMBOL_GPL(hvc_kick); |
1da177e4 | 319 | |
1da177e4 LT |
320 | static void hvc_unthrottle(struct tty_struct *tty) |
321 | { | |
322 | hvc_kick(); | |
323 | } | |
324 | ||
bdb498c2 JS |
325 | static int hvc_install(struct tty_driver *driver, struct tty_struct *tty) |
326 | { | |
327 | struct hvc_struct *hp; | |
328 | int rc; | |
329 | ||
330 | /* Auto increments kref reference if found. */ | |
b8dccc1b GKH |
331 | hp = hvc_get_by_index(tty->index); |
332 | if (!hp) | |
bdb498c2 JS |
333 | return -ENODEV; |
334 | ||
335 | tty->driver_data = hp; | |
336 | ||
337 | rc = tty_port_install(&hp->port, driver, tty); | |
338 | if (rc) | |
339 | tty_port_put(&hp->port); | |
340 | return rc; | |
341 | } | |
342 | ||
1da177e4 LT |
343 | /* |
344 | * The TTY interface won't be used until after the vio layer has exposed the vty | |
345 | * adapter to the kernel. | |
346 | */ | |
347 | static int hvc_open(struct tty_struct *tty, struct file * filp) | |
348 | { | |
cf9c9445 | 349 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 | 350 | unsigned long flags; |
1da177e4 | 351 | int rc = 0; |
1da177e4 | 352 | |
0146b693 | 353 | spin_lock_irqsave(&hp->port.lock, flags); |
1da177e4 | 354 | /* Check and then increment for fast path open. */ |
0146b693 JS |
355 | if (hp->port.count++ > 0) { |
356 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
1da177e4 | 357 | hvc_kick(); |
cf9c9445 | 358 | return 0; |
1da177e4 | 359 | } /* else count == 0 */ |
0146b693 | 360 | spin_unlock_irqrestore(&hp->port.lock, flags); |
1da177e4 | 361 | |
85bbc003 JS |
362 | tty_port_tty_set(&hp->port, tty); |
363 | ||
b1b135c8 CB |
364 | if (hp->ops->notifier_add) |
365 | rc = hp->ops->notifier_add(hp, hp->data); | |
1da177e4 LT |
366 | |
367 | /* | |
611e097d | 368 | * If the notifier fails we return an error. The tty layer |
1da177e4 LT |
369 | * will call hvc_close() after a failed open but we don't want to clean |
370 | * up there so we'll clean up here and clear out the previously set | |
12b20ded | 371 | * tty fields and return the kref reference. |
1da177e4 LT |
372 | */ |
373 | if (rc) { | |
1da177e4 | 374 | printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); |
24eb2377 | 375 | } else { |
33e745a1 HB |
376 | /* We are ready... raise DTR/RTS */ |
377 | if (C_BAUD(tty)) | |
378 | if (hp->ops->dtr_rts) | |
379 | hp->ops->dtr_rts(hp, 1); | |
24eb2377 JS |
380 | tty_port_set_initialized(&hp->port, true); |
381 | } | |
33e745a1 | 382 | |
1da177e4 LT |
383 | /* Force wakeup of the polling thread */ |
384 | hvc_kick(); | |
385 | ||
386 | return rc; | |
387 | } | |
388 | ||
389 | static void hvc_close(struct tty_struct *tty, struct file * filp) | |
390 | { | |
24eb2377 | 391 | struct hvc_struct *hp = tty->driver_data; |
1da177e4 LT |
392 | unsigned long flags; |
393 | ||
394 | if (tty_hung_up_p(filp)) | |
395 | return; | |
396 | ||
0146b693 | 397 | spin_lock_irqsave(&hp->port.lock, flags); |
1da177e4 | 398 | |
0146b693 JS |
399 | if (--hp->port.count == 0) { |
400 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
85bbc003 JS |
401 | /* We are done with the tty pointer now. */ |
402 | tty_port_tty_set(&hp->port, NULL); | |
1da177e4 | 403 | |
24eb2377 JS |
404 | if (!tty_port_initialized(&hp->port)) |
405 | return; | |
406 | ||
33e745a1 HB |
407 | if (C_HUPCL(tty)) |
408 | if (hp->ops->dtr_rts) | |
409 | hp->ops->dtr_rts(hp, 0); | |
410 | ||
eef2622a CB |
411 | if (hp->ops->notifier_del) |
412 | hp->ops->notifier_del(hp, hp->data); | |
413 | ||
febde371 HB |
414 | /* cancel pending tty resize work */ |
415 | cancel_work_sync(&hp->tty_resize); | |
416 | ||
1da177e4 LT |
417 | /* |
418 | * Chain calls chars_in_buffer() and returns immediately if | |
419 | * there is no buffered data otherwise sleeps on a wait queue | |
420 | * waking periodically to check chars_in_buffer(). | |
421 | */ | |
79c1faa4 | 422 | tty_wait_until_sent(tty, HVC_CLOSE_WAIT); |
24eb2377 | 423 | tty_port_set_initialized(&hp->port, false); |
1da177e4 | 424 | } else { |
0146b693 | 425 | if (hp->port.count < 0) |
1da177e4 | 426 | printk(KERN_ERR "hvc_close %X: oops, count is %d\n", |
0146b693 JS |
427 | hp->vtermno, hp->port.count); |
428 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
1da177e4 | 429 | } |
bdb498c2 JS |
430 | } |
431 | ||
432 | static void hvc_cleanup(struct tty_struct *tty) | |
433 | { | |
434 | struct hvc_struct *hp = tty->driver_data; | |
1da177e4 | 435 | |
f3d9f250 | 436 | tty_port_put(&hp->port); |
1da177e4 LT |
437 | } |
438 | ||
439 | static void hvc_hangup(struct tty_struct *tty) | |
440 | { | |
441 | struct hvc_struct *hp = tty->driver_data; | |
442 | unsigned long flags; | |
1da177e4 LT |
443 | |
444 | if (!hp) | |
445 | return; | |
446 | ||
febde371 HB |
447 | /* cancel pending tty resize work */ |
448 | cancel_work_sync(&hp->tty_resize); | |
449 | ||
0146b693 | 450 | spin_lock_irqsave(&hp->port.lock, flags); |
1da177e4 LT |
451 | |
452 | /* | |
453 | * The N_TTY line discipline has problems such that in a close vs | |
454 | * open->hangup case this can be called after the final close so prevent | |
455 | * that from happening for now. | |
456 | */ | |
0146b693 JS |
457 | if (hp->port.count <= 0) { |
458 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
1da177e4 LT |
459 | return; |
460 | } | |
461 | ||
0146b693 JS |
462 | hp->port.count = 0; |
463 | spin_unlock_irqrestore(&hp->port.lock, flags); | |
85bbc003 | 464 | tty_port_tty_set(&hp->port, NULL); |
eef2622a | 465 | |
0146b693 JS |
466 | hp->n_outbuf = 0; |
467 | ||
fc362e2e | 468 | if (hp->ops->notifier_hangup) |
e74d098c | 469 | hp->ops->notifier_hangup(hp, hp->data); |
1da177e4 LT |
470 | } |
471 | ||
472 | /* | |
473 | * Push buffered characters whether they were just recently buffered or waiting | |
474 | * on a blocked hypervisor. Call this function with hp->lock held. | |
475 | */ | |
3feebbb5 | 476 | static int hvc_push(struct hvc_struct *hp) |
1da177e4 LT |
477 | { |
478 | int n; | |
479 | ||
030ffad2 | 480 | n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
1da177e4 | 481 | if (n <= 0) { |
8c2381af | 482 | if (n == 0 || n == -EAGAIN) { |
45d607ed | 483 | hp->do_wakeup = 1; |
3feebbb5 | 484 | return 0; |
45d607ed | 485 | } |
1da177e4 LT |
486 | /* throw away output on error; this happens when |
487 | there is no session connected to the vterm. */ | |
488 | hp->n_outbuf = 0; | |
489 | } else | |
490 | hp->n_outbuf -= n; | |
491 | if (hp->n_outbuf > 0) | |
492 | memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); | |
493 | else | |
494 | hp->do_wakeup = 1; | |
3feebbb5 HB |
495 | |
496 | return n; | |
1da177e4 LT |
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 | ||
0146b693 JS |
509 | /* FIXME what's this (unprotected) check for? */ |
510 | if (hp->port.count <= 0) | |
45d607ed RA |
511 | return -EIO; |
512 | ||
550ddadc | 513 | while (count > 0) { |
7f2bf784 NP |
514 | int ret = 0; |
515 | ||
550ddadc | 516 | spin_lock_irqsave(&hp->lock, flags); |
1da177e4 | 517 | |
550ddadc NP |
518 | rsize = hp->outbuf_size - hp->n_outbuf; |
519 | ||
520 | if (rsize) { | |
521 | if (rsize > count) | |
522 | rsize = count; | |
523 | memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); | |
524 | count -= rsize; | |
525 | buf += rsize; | |
526 | hp->n_outbuf += rsize; | |
527 | written += rsize; | |
528 | } | |
529 | ||
530 | if (hp->n_outbuf > 0) | |
7f2bf784 | 531 | ret = hvc_push(hp); |
550ddadc NP |
532 | |
533 | spin_unlock_irqrestore(&hp->lock, flags); | |
534 | ||
7f2bf784 NP |
535 | if (!ret) |
536 | break; | |
537 | ||
9f65b81f NP |
538 | if (count) { |
539 | if (hp->n_outbuf > 0) | |
540 | hvc_flush(hp); | |
550ddadc | 541 | cond_resched(); |
9f65b81f | 542 | } |
1da177e4 | 543 | } |
1da177e4 | 544 | |
1da177e4 LT |
545 | /* |
546 | * Racy, but harmless, kick thread if there is still pending data. | |
1da177e4 LT |
547 | */ |
548 | if (hp->n_outbuf) | |
549 | hvc_kick(); | |
550 | ||
551 | return written; | |
552 | } | |
553 | ||
febde371 HB |
554 | /** |
555 | * hvc_set_winsz() - Resize the hvc tty terminal window. | |
556 | * @work: work structure. | |
557 | * | |
558 | * The routine shall not be called within an atomic context because it | |
559 | * might sleep. | |
560 | * | |
561 | * Locking: hp->lock | |
562 | */ | |
563 | static void hvc_set_winsz(struct work_struct *work) | |
564 | { | |
565 | struct hvc_struct *hp; | |
566 | unsigned long hvc_flags; | |
567 | struct tty_struct *tty; | |
568 | struct winsize ws; | |
569 | ||
570 | hp = container_of(work, struct hvc_struct, tty_resize); | |
febde371 | 571 | |
85bbc003 JS |
572 | tty = tty_port_tty_get(&hp->port); |
573 | if (!tty) | |
febde371 | 574 | return; |
85bbc003 JS |
575 | |
576 | spin_lock_irqsave(&hp->lock, hvc_flags); | |
577 | ws = hp->ws; | |
febde371 HB |
578 | spin_unlock_irqrestore(&hp->lock, hvc_flags); |
579 | ||
fc6f6238 | 580 | tty_do_resize(tty, &ws); |
febde371 HB |
581 | tty_kref_put(tty); |
582 | } | |
583 | ||
1da177e4 LT |
584 | /* |
585 | * This is actually a contract between the driver and the tty layer outlining | |
c3ea6921 | 586 | * how much write room the driver can guarantee will be sent OR BUFFERED. This |
1da177e4 LT |
587 | * driver MUST honor the return value. |
588 | */ | |
03b3b1a2 | 589 | static unsigned int hvc_write_room(struct tty_struct *tty) |
1da177e4 LT |
590 | { |
591 | struct hvc_struct *hp = tty->driver_data; | |
592 | ||
593 | if (!hp) | |
d83114e9 | 594 | return 0; |
1da177e4 | 595 | |
4e9e95a3 | 596 | return hp->outbuf_size - hp->n_outbuf; |
1da177e4 LT |
597 | } |
598 | ||
599 | static int hvc_chars_in_buffer(struct tty_struct *tty) | |
600 | { | |
601 | struct hvc_struct *hp = tty->driver_data; | |
602 | ||
603 | if (!hp) | |
23198fda | 604 | return 0; |
1da177e4 LT |
605 | return hp->n_outbuf; |
606 | } | |
607 | ||
b791072b WS |
608 | /* |
609 | * timeout will vary between the MIN and MAX values defined here. By default | |
610 | * and during console activity we will use a default MIN_TIMEOUT of 10. When | |
611 | * the console is idle, we increase the timeout value on each pass through | |
612 | * msleep until we reach the max. This may be noticeable as a brief (average | |
613 | * one second) delay on the console before the console responds to input when | |
614 | * there has been no input for some time. | |
615 | */ | |
616 | #define MIN_TIMEOUT (10) | |
617 | #define MAX_TIMEOUT (2000) | |
618 | static u32 timeout = MIN_TIMEOUT; | |
619 | ||
68b2fc71 NP |
620 | /* |
621 | * Maximum number of bytes to get from the console driver if hvc_poll is | |
622 | * called from driver (and can't sleep). Any more than this and we break | |
623 | * and start polling with khvcd. This value was derived from from an OpenBMC | |
624 | * console with the OPAL driver that results in about 0.25ms interrupts off | |
625 | * latency. | |
626 | */ | |
627 | #define HVC_ATOMIC_READ_MAX 128 | |
628 | ||
1da177e4 LT |
629 | #define HVC_POLL_READ 0x00000001 |
630 | #define HVC_POLL_WRITE 0x00000002 | |
1da177e4 | 631 | |
cfb5946b | 632 | static int __hvc_poll(struct hvc_struct *hp, bool may_sleep) |
1da177e4 LT |
633 | { |
634 | struct tty_struct *tty; | |
ec97eaad | 635 | int i, n, count, poll_mask = 0; |
1da177e4 LT |
636 | char buf[N_INBUF] __ALIGNED__; |
637 | unsigned long flags; | |
638 | int read_total = 0; | |
3feebbb5 | 639 | int written_total = 0; |
1da177e4 LT |
640 | |
641 | spin_lock_irqsave(&hp->lock, flags); | |
642 | ||
643 | /* Push pending writes */ | |
644 | if (hp->n_outbuf > 0) | |
3feebbb5 | 645 | written_total = hvc_push(hp); |
b5374461 | 646 | |
1da177e4 | 647 | /* Reschedule us if still some write pending */ |
3feebbb5 | 648 | if (hp->n_outbuf > 0) { |
1da177e4 | 649 | poll_mask |= HVC_POLL_WRITE; |
3feebbb5 HB |
650 | /* If hvc_push() was not able to write, sleep a few msecs */ |
651 | timeout = (written_total) ? 0 : MIN_TIMEOUT; | |
652 | } | |
1da177e4 | 653 | |
cfb5946b NP |
654 | if (may_sleep) { |
655 | spin_unlock_irqrestore(&hp->lock, flags); | |
656 | cond_resched(); | |
657 | spin_lock_irqsave(&hp->lock, flags); | |
658 | } | |
659 | ||
1da177e4 | 660 | /* No tty attached, just skip */ |
85bbc003 | 661 | tty = tty_port_tty_get(&hp->port); |
1da177e4 LT |
662 | if (tty == NULL) |
663 | goto bail; | |
664 | ||
665 | /* Now check if we can get data (are we throttled ?) */ | |
97ef38b8 | 666 | if (tty_throttled(tty)) |
ec97eaad | 667 | goto out; |
1da177e4 | 668 | |
611e097d | 669 | /* If we aren't notifier driven and aren't throttled, we always |
1da177e4 LT |
670 | * request a reschedule |
671 | */ | |
611e097d | 672 | if (!hp->irq_requested) |
1da177e4 LT |
673 | poll_mask |= HVC_POLL_READ; |
674 | ||
68b2fc71 | 675 | read_again: |
1da177e4 | 676 | /* Read data if any */ |
ec97eaad NP |
677 | count = tty_buffer_request_room(&hp->port, N_INBUF); |
678 | ||
679 | /* If flip is full, just reschedule a later read */ | |
680 | if (count == 0) { | |
681 | poll_mask |= HVC_POLL_READ; | |
682 | goto out; | |
683 | } | |
684 | ||
685 | n = hp->ops->get_chars(hp->vtermno, buf, count); | |
686 | if (n <= 0) { | |
687 | /* Hangup the tty when disconnected from host */ | |
688 | if (n == -EPIPE) { | |
689 | spin_unlock_irqrestore(&hp->lock, flags); | |
690 | tty_hangup(tty); | |
691 | spin_lock_irqsave(&hp->lock, flags); | |
692 | } else if ( n == -EAGAIN ) { | |
693 | /* | |
694 | * Some back-ends can only ensure a certain min | |
695 | * num of bytes read, which may be > 'count'. | |
696 | * Let the tty clear the flip buff to make room. | |
697 | */ | |
1da177e4 | 698 | poll_mask |= HVC_POLL_READ; |
1da177e4 | 699 | } |
ec97eaad NP |
700 | goto out; |
701 | } | |
1da177e4 | 702 | |
ec97eaad | 703 | for (i = 0; i < n; ++i) { |
1da177e4 | 704 | #ifdef CONFIG_MAGIC_SYSRQ |
ec97eaad NP |
705 | if (hp->index == hvc_console.index) { |
706 | /* Handle the SysRq Hack */ | |
707 | /* XXX should support a sequence */ | |
708 | if (buf[i] == '\x0f') { /* ^O */ | |
709 | /* if ^O is pressed again, reset | |
710 | * sysrq_pressed and flip ^O char */ | |
711 | sysrq_pressed = !sysrq_pressed; | |
712 | if (sysrq_pressed) | |
2b9e0bac | 713 | continue; |
ec97eaad NP |
714 | } else if (sysrq_pressed) { |
715 | handle_sysrq(buf[i]); | |
716 | sysrq_pressed = 0; | |
717 | continue; | |
1da177e4 | 718 | } |
1da177e4 | 719 | } |
ec97eaad NP |
720 | #endif /* CONFIG_MAGIC_SYSRQ */ |
721 | tty_insert_flip_char(&hp->port, buf[i], 0); | |
1da177e4 | 722 | } |
68b2fc71 NP |
723 | read_total += n; |
724 | ||
725 | if (may_sleep) { | |
726 | /* Keep going until the flip is full */ | |
727 | spin_unlock_irqrestore(&hp->lock, flags); | |
728 | cond_resched(); | |
729 | spin_lock_irqsave(&hp->lock, flags); | |
730 | goto read_again; | |
731 | } else if (read_total < HVC_ATOMIC_READ_MAX) { | |
732 | /* Break and defer if it's a large read in atomic */ | |
733 | goto read_again; | |
734 | } | |
ec97eaad | 735 | |
6e7f6b82 NP |
736 | /* |
737 | * Latency break, schedule another poll immediately. | |
738 | */ | |
739 | poll_mask |= HVC_POLL_READ; | |
740 | ||
ec97eaad | 741 | out: |
1da177e4 LT |
742 | /* Wakeup write queue if necessary */ |
743 | if (hp->do_wakeup) { | |
744 | hp->do_wakeup = 0; | |
745 | tty_wakeup(tty); | |
746 | } | |
747 | bail: | |
748 | spin_unlock_irqrestore(&hp->lock, flags); | |
749 | ||
b791072b WS |
750 | if (read_total) { |
751 | /* Activity is occurring, so reset the polling backoff value to | |
752 | a minimum for performance. */ | |
753 | timeout = MIN_TIMEOUT; | |
754 | ||
2e124b4a | 755 | tty_flip_buffer_push(&hp->port); |
b791072b | 756 | } |
85bbc003 | 757 | tty_kref_put(tty); |
b791072b | 758 | |
1da177e4 LT |
759 | return poll_mask; |
760 | } | |
cfb5946b NP |
761 | |
762 | int hvc_poll(struct hvc_struct *hp) | |
763 | { | |
764 | return __hvc_poll(hp, false); | |
765 | } | |
7721c494 | 766 | EXPORT_SYMBOL_GPL(hvc_poll); |
1da177e4 | 767 | |
febde371 | 768 | /** |
254be490 | 769 | * __hvc_resize() - Update terminal window size information. |
febde371 HB |
770 | * @hp: HVC console pointer |
771 | * @ws: Terminal window size structure | |
772 | * | |
773 | * Stores the specified window size information in the hvc structure of @hp. | |
774 | * The function schedule the tty resize update. | |
775 | * | |
776 | * Locking: Locking free; the function MUST be called holding hp->lock | |
777 | */ | |
254be490 | 778 | void __hvc_resize(struct hvc_struct *hp, struct winsize ws) |
febde371 | 779 | { |
7947cf0d HB |
780 | hp->ws = ws; |
781 | schedule_work(&hp->tty_resize); | |
febde371 | 782 | } |
254be490 | 783 | EXPORT_SYMBOL_GPL(__hvc_resize); |
febde371 | 784 | |
1da177e4 LT |
785 | /* |
786 | * This kthread is either polling or interrupt driven. This is determined by | |
787 | * calling hvc_poll() who determines whether a console adapter support | |
788 | * interrupts. | |
789 | */ | |
5605d4de | 790 | static int khvcd(void *unused) |
1da177e4 LT |
791 | { |
792 | int poll_mask; | |
793 | struct hvc_struct *hp; | |
794 | ||
83144186 | 795 | set_freezable(); |
1da177e4 LT |
796 | do { |
797 | poll_mask = 0; | |
798 | hvc_kicked = 0; | |
b64074e4 | 799 | try_to_freeze(); |
1da177e4 | 800 | wmb(); |
1c8950ff | 801 | if (!cpus_are_in_xmon()) { |
a9bf5c8a | 802 | mutex_lock(&hvc_structs_mutex); |
1da177e4 | 803 | list_for_each_entry(hp, &hvc_structs, next) { |
cfb5946b NP |
804 | poll_mask |= __hvc_poll(hp, true); |
805 | cond_resched(); | |
1da177e4 | 806 | } |
a9bf5c8a | 807 | mutex_unlock(&hvc_structs_mutex); |
1da177e4 LT |
808 | } else |
809 | poll_mask |= HVC_POLL_READ; | |
810 | if (hvc_kicked) | |
811 | continue; | |
1da177e4 LT |
812 | set_current_state(TASK_INTERRUPTIBLE); |
813 | if (!hvc_kicked) { | |
814 | if (poll_mask == 0) | |
815 | schedule(); | |
b791072b | 816 | else { |
15a27431 BH |
817 | unsigned long j_timeout; |
818 | ||
b791072b WS |
819 | if (timeout < MAX_TIMEOUT) |
820 | timeout += (timeout >> 6) + 1; | |
821 | ||
15a27431 BH |
822 | /* |
823 | * We don't use msleep_interruptible otherwise | |
824 | * "kick" will fail to wake us up | |
825 | */ | |
826 | j_timeout = msecs_to_jiffies(timeout) + 1; | |
827 | schedule_timeout_interruptible(j_timeout); | |
b791072b | 828 | } |
1da177e4 LT |
829 | } |
830 | __set_current_state(TASK_RUNNING); | |
831 | } while (!kthread_should_stop()); | |
832 | ||
833 | return 0; | |
834 | } | |
835 | ||
4d2bb3f5 BH |
836 | static int hvc_tiocmget(struct tty_struct *tty) |
837 | { | |
838 | struct hvc_struct *hp = tty->driver_data; | |
839 | ||
840 | if (!hp || !hp->ops->tiocmget) | |
841 | return -EINVAL; | |
842 | return hp->ops->tiocmget(hp); | |
843 | } | |
844 | ||
845 | static int hvc_tiocmset(struct tty_struct *tty, | |
846 | unsigned int set, unsigned int clear) | |
847 | { | |
848 | struct hvc_struct *hp = tty->driver_data; | |
849 | ||
850 | if (!hp || !hp->ops->tiocmset) | |
851 | return -EINVAL; | |
852 | return hp->ops->tiocmset(hp, set, clear); | |
853 | } | |
854 | ||
762e77ae | 855 | #ifdef CONFIG_CONSOLE_POLL |
5855b210 | 856 | static int hvc_poll_init(struct tty_driver *driver, int line, char *options) |
762e77ae AB |
857 | { |
858 | return 0; | |
859 | } | |
860 | ||
861 | static int hvc_poll_get_char(struct tty_driver *driver, int line) | |
862 | { | |
863 | struct tty_struct *tty = driver->ttys[0]; | |
864 | struct hvc_struct *hp = tty->driver_data; | |
865 | int n; | |
866 | char ch; | |
867 | ||
868 | n = hp->ops->get_chars(hp->vtermno, &ch, 1); | |
869 | ||
fab794ae | 870 | if (n <= 0) |
762e77ae AB |
871 | return NO_POLL_CHAR; |
872 | ||
873 | return ch; | |
874 | } | |
875 | ||
876 | static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch) | |
877 | { | |
878 | struct tty_struct *tty = driver->ttys[0]; | |
879 | struct hvc_struct *hp = tty->driver_data; | |
880 | int n; | |
881 | ||
882 | do { | |
883 | n = hp->ops->put_chars(hp->vtermno, &ch, 1); | |
884 | } while (n <= 0); | |
885 | } | |
886 | #endif | |
887 | ||
b68e31d0 | 888 | static const struct tty_operations hvc_ops = { |
bdb498c2 | 889 | .install = hvc_install, |
1da177e4 LT |
890 | .open = hvc_open, |
891 | .close = hvc_close, | |
bdb498c2 | 892 | .cleanup = hvc_cleanup, |
1da177e4 LT |
893 | .write = hvc_write, |
894 | .hangup = hvc_hangup, | |
895 | .unthrottle = hvc_unthrottle, | |
896 | .write_room = hvc_write_room, | |
897 | .chars_in_buffer = hvc_chars_in_buffer, | |
4d2bb3f5 BH |
898 | .tiocmget = hvc_tiocmget, |
899 | .tiocmset = hvc_tiocmset, | |
762e77ae AB |
900 | #ifdef CONFIG_CONSOLE_POLL |
901 | .poll_init = hvc_poll_init, | |
902 | .poll_get_char = hvc_poll_get_char, | |
903 | .poll_put_char = hvc_poll_put_char, | |
904 | #endif | |
1da177e4 LT |
905 | }; |
906 | ||
f3d9f250 JS |
907 | static const struct tty_port_operations hvc_port_ops = { |
908 | .destruct = hvc_port_destruct, | |
909 | }; | |
910 | ||
119ea109 AS |
911 | struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, |
912 | const struct hv_ops *ops, | |
913 | int outbuf_size) | |
1da177e4 LT |
914 | { |
915 | struct hvc_struct *hp; | |
6f24808e | 916 | int i; |
1da177e4 | 917 | |
3e6c6f63 | 918 | /* We wait until a driver actually comes along */ |
f76a1cbe | 919 | if (atomic_inc_not_zero(&hvc_needs_init)) { |
3e6c6f63 RR |
920 | int err = hvc_init(); |
921 | if (err) | |
922 | return ERR_PTR(err); | |
923 | } | |
924 | ||
2da7582f | 925 | hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
4e9e95a3 | 926 | GFP_KERNEL); |
1da177e4 | 927 | if (!hp) |
acad9559 | 928 | return ERR_PTR(-ENOMEM); |
1da177e4 | 929 | |
acad9559 | 930 | hp->vtermno = vtermno; |
611e097d | 931 | hp->data = data; |
030ffad2 | 932 | hp->ops = ops; |
4e9e95a3 SR |
933 | hp->outbuf_size = outbuf_size; |
934 | hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; | |
1da177e4 | 935 | |
f3d9f250 JS |
936 | tty_port_init(&hp->port); |
937 | hp->port.ops = &hvc_port_ops; | |
1da177e4 | 938 | |
febde371 | 939 | INIT_WORK(&hp->tty_resize, hvc_set_winsz); |
1da177e4 | 940 | spin_lock_init(&hp->lock); |
a9bf5c8a | 941 | mutex_lock(&hvc_structs_mutex); |
6f24808e MM |
942 | |
943 | /* | |
944 | * find index to use: | |
945 | * see if this vterm id matches one registered for console. | |
946 | */ | |
31555213 | 947 | for (i=0; i < MAX_NR_HVC_CONSOLES; i++) |
45d607ed RA |
948 | if (vtermnos[i] == hp->vtermno && |
949 | cons_ops[i] == hp->ops) | |
6f24808e MM |
950 | break; |
951 | ||
9a9fc42b AM |
952 | if (i >= MAX_NR_HVC_CONSOLES) { |
953 | ||
954 | /* find 'empty' slot for console */ | |
955 | for (i = 0; i < MAX_NR_HVC_CONSOLES && vtermnos[i] != -1; i++) { | |
956 | } | |
957 | ||
958 | /* no matching slot, just use a counter */ | |
959 | if (i == MAX_NR_HVC_CONSOLES) | |
960 | i = ++last_hvc + MAX_NR_HVC_CONSOLES; | |
961 | } | |
6f24808e MM |
962 | |
963 | hp->index = i; | |
9a9fc42b AM |
964 | if (i < MAX_NR_HVC_CONSOLES) { |
965 | cons_ops[i] = ops; | |
966 | vtermnos[i] = vtermno; | |
967 | } | |
6f24808e | 968 | |
1da177e4 | 969 | list_add_tail(&(hp->next), &hvc_structs); |
a9bf5c8a | 970 | mutex_unlock(&hvc_structs_mutex); |
1da177e4 | 971 | |
92057a49 BH |
972 | /* check if we need to re-register the kernel console */ |
973 | hvc_check_console(i); | |
974 | ||
acad9559 | 975 | return hp; |
1da177e4 | 976 | } |
7721c494 | 977 | EXPORT_SYMBOL_GPL(hvc_alloc); |
1da177e4 | 978 | |
934752d8 | 979 | int hvc_remove(struct hvc_struct *hp) |
1da177e4 | 980 | { |
1da177e4 | 981 | unsigned long flags; |
1da177e4 LT |
982 | struct tty_struct *tty; |
983 | ||
85bbc003 | 984 | tty = tty_port_tty_get(&hp->port); |
1da177e4 | 985 | |
19fa6e60 | 986 | console_lock(); |
85bbc003 | 987 | spin_lock_irqsave(&hp->lock, flags); |
92057a49 | 988 | if (hp->index < MAX_NR_HVC_CONSOLES) { |
1da177e4 | 989 | vtermnos[hp->index] = -1; |
92057a49 | 990 | cons_ops[hp->index] = NULL; |
92057a49 | 991 | } |
1da177e4 LT |
992 | |
993 | /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ | |
994 | ||
995 | spin_unlock_irqrestore(&hp->lock, flags); | |
19fa6e60 | 996 | console_unlock(); |
1da177e4 LT |
997 | |
998 | /* | |
12b20ded GKH |
999 | * We 'put' the instance that was grabbed when the kref instance |
1000 | * was initialized using kref_init(). Let the last holder of this | |
e74d098c | 1001 | * kref cause it to be removed, which will probably be the tty_vhangup |
1da177e4 LT |
1002 | * below. |
1003 | */ | |
f3d9f250 | 1004 | tty_port_put(&hp->port); |
1da177e4 LT |
1005 | |
1006 | /* | |
e74d098c | 1007 | * This function call will auto chain call hvc_hangup. |
1da177e4 | 1008 | */ |
e74d098c AS |
1009 | if (tty) { |
1010 | tty_vhangup(tty); | |
1011 | tty_kref_put(tty); | |
1012 | } | |
1da177e4 LT |
1013 | return 0; |
1014 | } | |
c0cefebc | 1015 | EXPORT_SYMBOL_GPL(hvc_remove); |
1da177e4 | 1016 | |
3e6c6f63 RR |
1017 | /* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
1018 | static int hvc_init(void) | |
1da177e4 | 1019 | { |
55aab8cd | 1020 | struct tty_driver *drv; |
3e6c6f63 | 1021 | int err; |
55aab8cd | 1022 | |
5f6d9c07 | 1023 | /* We need more than hvc_count adapters due to hotplug additions. */ |
55aab8cd | 1024 | drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
3e6c6f63 RR |
1025 | if (!drv) { |
1026 | err = -ENOMEM; | |
1027 | goto out; | |
1028 | } | |
1da177e4 | 1029 | |
55aab8cd MN |
1030 | drv->driver_name = "hvc"; |
1031 | drv->name = "hvc"; | |
1032 | drv->major = HVC_MAJOR; | |
1033 | drv->minor_start = HVC_MINOR; | |
1034 | drv->type = TTY_DRIVER_TYPE_SYSTEM; | |
1035 | drv->init_termios = tty_std_termios; | |
56ce9e2b | 1036 | drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; |
55aab8cd | 1037 | tty_set_operations(drv, &hvc_ops); |
1da177e4 | 1038 | |
1da177e4 LT |
1039 | /* Always start the kthread because there can be hotplug vty adapters |
1040 | * added later. */ | |
1041 | hvc_task = kthread_run(khvcd, NULL, "khvcd"); | |
1042 | if (IS_ERR(hvc_task)) { | |
3e6c6f63 RR |
1043 | printk(KERN_ERR "Couldn't create kthread for console.\n"); |
1044 | err = PTR_ERR(hvc_task); | |
1045 | goto put_tty; | |
1da177e4 LT |
1046 | } |
1047 | ||
3e6c6f63 RR |
1048 | err = tty_register_driver(drv); |
1049 | if (err) { | |
1050 | printk(KERN_ERR "Couldn't register hvc console driver\n"); | |
1051 | goto stop_thread; | |
1052 | } | |
ef4cbee0 | 1053 | |
9fef3d2d MM |
1054 | /* |
1055 | * Make sure tty is fully registered before allowing it to be | |
1056 | * found by hvc_console_device. | |
1057 | */ | |
1058 | smp_mb(); | |
55aab8cd | 1059 | hvc_driver = drv; |
acad9559 | 1060 | return 0; |
3e6c6f63 | 1061 | |
3e6c6f63 RR |
1062 | stop_thread: |
1063 | kthread_stop(hvc_task); | |
1064 | hvc_task = NULL; | |
2571cd6a JL |
1065 | put_tty: |
1066 | put_tty_driver(drv); | |
3e6c6f63 RR |
1067 | out: |
1068 | return err; | |
1da177e4 | 1069 | } |