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
7 * Additional Author(s):
8 * Ryan S. Arnold <rsa@us.ibm.com>
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.
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.
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
25 #include <linux/console.h>
26 #include <linux/cpumask.h>
27 #include <linux/init.h>
28 #include <linux/kbd_kern.h>
29 #include <linux/kernel.h>
30 #include <linux/kthread.h>
31 #include <linux/list.h>
32 #include <linux/module.h>
33 #include <linux/major.h>
34 #include <linux/sysrq.h>
35 #include <linux/tty.h>
36 #include <linux/tty_flip.h>
37 #include <linux/sched.h>
38 #include <linux/spinlock.h>
39 #include <linux/delay.h>
40 #include <linux/freezer.h>
41 #include <linux/slab.h>
42 #include <linux/serial_core.h>
44 #include <asm/uaccess.h>
46 #include "hvc_console.h"
52 * Wait this long per iteration while trying to push buffered data to the
53 * hypervisor before allowing the tty to complete a close operation.
55 #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
58 * These sizes are most efficient for vio, because they are the
59 * native transfer size. We could make them selectable in the
60 * future to better deal with backends that want other buffer sizes.
65 #define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
67 static struct tty_driver
*hvc_driver
;
68 static struct task_struct
*hvc_task
;
70 /* Picks up late kicks after list walk but before schedule() */
71 static int hvc_kicked
;
73 static int hvc_init(void);
75 #ifdef CONFIG_MAGIC_SYSRQ
76 static int sysrq_pressed
;
79 /* dynamic list of hvc_struct instances */
80 static LIST_HEAD(hvc_structs
);
83 * Protect the list of hvc_struct instances from inserts and removals during
86 static DEFINE_SPINLOCK(hvc_structs_lock
);
89 * This value is used to assign a tty->index value to a hvc_struct based
90 * upon order of exposure via hvc_probe(), when we can not match it to
91 * a console candidate registered with hvc_instantiate().
93 static int last_hvc
= -1;
96 * Do not call this function with either the hvc_structs_lock or the hvc_struct
97 * lock held. If successful, this function increments the kref reference
98 * count against the target hvc_struct so it should be released when finished.
100 static struct hvc_struct
*hvc_get_by_index(int index
)
102 struct hvc_struct
*hp
;
105 spin_lock(&hvc_structs_lock
);
107 list_for_each_entry(hp
, &hvc_structs
, next
) {
108 spin_lock_irqsave(&hp
->lock
, flags
);
109 if (hp
->index
== index
) {
111 spin_unlock_irqrestore(&hp
->lock
, flags
);
112 spin_unlock(&hvc_structs_lock
);
115 spin_unlock_irqrestore(&hp
->lock
, flags
);
119 spin_unlock(&hvc_structs_lock
);
125 * Initial console vtermnos for console API usage prior to full console
126 * initialization. Any vty adapter outside this range will not have usable
127 * console interfaces but can still be used as a tty device. This has to be
128 * static because kmalloc will not work during early console init.
130 static const struct hv_ops
*cons_ops
[MAX_NR_HVC_CONSOLES
];
131 static uint32_t vtermnos
[MAX_NR_HVC_CONSOLES
] =
132 {[0 ... MAX_NR_HVC_CONSOLES
- 1] = -1};
135 * Console APIs, NOT TTY. These APIs are available immediately when
136 * hvc_console_setup() finds adapters.
139 static void hvc_console_print(struct console
*co
, const char *b
,
142 char c
[N_OUTBUF
] __ALIGNED__
;
143 unsigned i
= 0, n
= 0;
144 int r
, donecr
= 0, index
= co
->index
;
146 /* Console access attempt outside of acceptable console range. */
147 if (index
>= MAX_NR_HVC_CONSOLES
)
150 /* This console adapter was removed so it is not usable. */
151 if (vtermnos
[index
] == -1)
154 while (count
> 0 || i
> 0) {
155 if (count
> 0 && i
< sizeof(c
)) {
156 if (b
[n
] == '\n' && !donecr
) {
165 r
= cons_ops
[index
]->put_chars(vtermnos
[index
], c
, i
);
167 /* throw away characters on error
168 * but spin in case of -EAGAIN */
180 static struct tty_driver
*hvc_console_device(struct console
*c
, int *index
)
182 if (vtermnos
[c
->index
] == -1)
189 static int __init
hvc_console_setup(struct console
*co
, char *options
)
191 if (co
->index
< 0 || co
->index
>= MAX_NR_HVC_CONSOLES
)
194 if (vtermnos
[co
->index
] == -1)
200 static struct console hvc_console
= {
202 .write
= hvc_console_print
,
203 .device
= hvc_console_device
,
204 .setup
= hvc_console_setup
,
205 .flags
= CON_PRINTBUFFER
,
210 * Early console initialization. Precedes driver initialization.
212 * (1) we are first, and the user specified another driver
213 * -- index will remain -1
214 * (2) we are first and the user specified no driver
215 * -- index will be set to 0, then we will fail setup.
216 * (3) we are first and the user specified our driver
217 * -- index will be set to user specified driver, and we will fail
218 * (4) we are after driver, and this initcall will register us
219 * -- if the user didn't specify a driver then the console will match
221 * Note that for cases 2 and 3, we will match later when the io driver
222 * calls hvc_instantiate() and call register again.
224 static int __init
hvc_console_init(void)
226 register_console(&hvc_console
);
229 console_initcall(hvc_console_init
);
231 /* callback when the kboject ref count reaches zero. */
232 static void destroy_hvc_struct(struct kref
*kref
)
234 struct hvc_struct
*hp
= container_of(kref
, struct hvc_struct
, kref
);
237 spin_lock(&hvc_structs_lock
);
239 spin_lock_irqsave(&hp
->lock
, flags
);
240 list_del(&(hp
->next
));
241 spin_unlock_irqrestore(&hp
->lock
, flags
);
243 spin_unlock(&hvc_structs_lock
);
249 * hvc_instantiate() is an early console discovery method which locates
250 * consoles * prior to the vio subsystem discovering them. Hotplugged
251 * vty adapters do NOT get an hvc_instantiate() callback since they
252 * appear after early console init.
254 int hvc_instantiate(uint32_t vtermno
, int index
, const struct hv_ops
*ops
)
256 struct hvc_struct
*hp
;
258 if (index
< 0 || index
>= MAX_NR_HVC_CONSOLES
)
261 if (vtermnos
[index
] != -1)
264 /* make sure no no tty has been registered in this index */
265 hp
= hvc_get_by_index(index
);
267 kref_put(&hp
->kref
, destroy_hvc_struct
);
271 vtermnos
[index
] = vtermno
;
272 cons_ops
[index
] = ops
;
274 /* reserve all indices up to and including this index */
275 if (last_hvc
< index
)
278 /* if this index is what the user requested, then register
279 * now (setup won't fail at this point). It's ok to just
280 * call register again if previously .setup failed.
282 if (index
== hvc_console
.index
)
283 register_console(&hvc_console
);
287 EXPORT_SYMBOL_GPL(hvc_instantiate
);
289 /* Wake the sleeping khvcd */
293 wake_up_process(hvc_task
);
295 EXPORT_SYMBOL_GPL(hvc_kick
);
297 static void hvc_unthrottle(struct tty_struct
*tty
)
303 * The TTY interface won't be used until after the vio layer has exposed the vty
304 * adapter to the kernel.
306 static int hvc_open(struct tty_struct
*tty
, struct file
* filp
)
308 struct hvc_struct
*hp
;
312 /* Auto increments kref reference if found. */
313 if (!(hp
= hvc_get_by_index(tty
->index
)))
316 spin_lock_irqsave(&hp
->lock
, flags
);
317 /* Check and then increment for fast path open. */
318 if (hp
->count
++ > 0) {
320 spin_unlock_irqrestore(&hp
->lock
, flags
);
323 } /* else count == 0 */
325 tty
->driver_data
= hp
;
327 hp
->tty
= tty_kref_get(tty
);
329 spin_unlock_irqrestore(&hp
->lock
, flags
);
331 if (hp
->ops
->notifier_add
)
332 rc
= hp
->ops
->notifier_add(hp
, hp
->data
);
335 * If the notifier fails we return an error. The tty layer
336 * will call hvc_close() after a failed open but we don't want to clean
337 * up there so we'll clean up here and clear out the previously set
338 * tty fields and return the kref reference.
341 spin_lock_irqsave(&hp
->lock
, flags
);
343 spin_unlock_irqrestore(&hp
->lock
, flags
);
345 tty
->driver_data
= NULL
;
346 kref_put(&hp
->kref
, destroy_hvc_struct
);
347 printk(KERN_ERR
"hvc_open: request_irq failed with rc %d.\n", rc
);
349 /* Force wakeup of the polling thread */
355 static void hvc_close(struct tty_struct
*tty
, struct file
* filp
)
357 struct hvc_struct
*hp
;
360 if (tty_hung_up_p(filp
))
364 * No driver_data means that this close was issued after a failed
365 * hvc_open by the tty layer's release_dev() function and we can just
366 * exit cleanly because the kref reference wasn't made.
368 if (!tty
->driver_data
)
371 hp
= tty
->driver_data
;
373 spin_lock_irqsave(&hp
->lock
, flags
);
375 if (--hp
->count
== 0) {
376 /* We are done with the tty pointer now. */
378 spin_unlock_irqrestore(&hp
->lock
, flags
);
380 if (hp
->ops
->notifier_del
)
381 hp
->ops
->notifier_del(hp
, hp
->data
);
383 /* cancel pending tty resize work */
384 cancel_work_sync(&hp
->tty_resize
);
387 * Chain calls chars_in_buffer() and returns immediately if
388 * there is no buffered data otherwise sleeps on a wait queue
389 * waking periodically to check chars_in_buffer().
391 tty_wait_until_sent(tty
, HVC_CLOSE_WAIT
);
394 printk(KERN_ERR
"hvc_close %X: oops, count is %d\n",
395 hp
->vtermno
, hp
->count
);
396 spin_unlock_irqrestore(&hp
->lock
, flags
);
400 kref_put(&hp
->kref
, destroy_hvc_struct
);
403 static void hvc_hangup(struct tty_struct
*tty
)
405 struct hvc_struct
*hp
= tty
->driver_data
;
412 /* cancel pending tty resize work */
413 cancel_work_sync(&hp
->tty_resize
);
415 spin_lock_irqsave(&hp
->lock
, flags
);
418 * The N_TTY line discipline has problems such that in a close vs
419 * open->hangup case this can be called after the final close so prevent
420 * that from happening for now.
422 if (hp
->count
<= 0) {
423 spin_unlock_irqrestore(&hp
->lock
, flags
);
427 temp_open_count
= hp
->count
;
432 spin_unlock_irqrestore(&hp
->lock
, flags
);
434 if (hp
->ops
->notifier_hangup
)
435 hp
->ops
->notifier_hangup(hp
, hp
->data
);
437 while(temp_open_count
) {
440 kref_put(&hp
->kref
, destroy_hvc_struct
);
445 * Push buffered characters whether they were just recently buffered or waiting
446 * on a blocked hypervisor. Call this function with hp->lock held.
448 static int hvc_push(struct hvc_struct
*hp
)
452 n
= hp
->ops
->put_chars(hp
->vtermno
, hp
->outbuf
, hp
->n_outbuf
);
454 if (n
== 0 || n
== -EAGAIN
) {
458 /* throw away output on error; this happens when
459 there is no session connected to the vterm. */
463 if (hp
->n_outbuf
> 0)
464 memmove(hp
->outbuf
, hp
->outbuf
+ n
, hp
->n_outbuf
);
471 static int hvc_write(struct tty_struct
*tty
, const unsigned char *buf
, int count
)
473 struct hvc_struct
*hp
= tty
->driver_data
;
475 int rsize
, written
= 0;
477 /* This write was probably executed during a tty close. */
484 spin_lock_irqsave(&hp
->lock
, flags
);
486 /* Push pending writes */
487 if (hp
->n_outbuf
> 0)
490 while (count
> 0 && (rsize
= hp
->outbuf_size
- hp
->n_outbuf
) > 0) {
493 memcpy(hp
->outbuf
+ hp
->n_outbuf
, buf
, rsize
);
496 hp
->n_outbuf
+= rsize
;
500 spin_unlock_irqrestore(&hp
->lock
, flags
);
503 * Racy, but harmless, kick thread if there is still pending data.
512 * hvc_set_winsz() - Resize the hvc tty terminal window.
513 * @work: work structure.
515 * The routine shall not be called within an atomic context because it
520 static void hvc_set_winsz(struct work_struct
*work
)
522 struct hvc_struct
*hp
;
523 unsigned long hvc_flags
;
524 struct tty_struct
*tty
;
527 hp
= container_of(work
, struct hvc_struct
, tty_resize
);
529 spin_lock_irqsave(&hp
->lock
, hvc_flags
);
531 spin_unlock_irqrestore(&hp
->lock
, hvc_flags
);
535 tty
= tty_kref_get(hp
->tty
);
536 spin_unlock_irqrestore(&hp
->lock
, hvc_flags
);
538 tty_do_resize(tty
, &ws
);
543 * This is actually a contract between the driver and the tty layer outlining
544 * how much write room the driver can guarantee will be sent OR BUFFERED. This
545 * driver MUST honor the return value.
547 static int hvc_write_room(struct tty_struct
*tty
)
549 struct hvc_struct
*hp
= tty
->driver_data
;
554 return hp
->outbuf_size
- hp
->n_outbuf
;
557 static int hvc_chars_in_buffer(struct tty_struct
*tty
)
559 struct hvc_struct
*hp
= tty
->driver_data
;
567 * timeout will vary between the MIN and MAX values defined here. By default
568 * and during console activity we will use a default MIN_TIMEOUT of 10. When
569 * the console is idle, we increase the timeout value on each pass through
570 * msleep until we reach the max. This may be noticeable as a brief (average
571 * one second) delay on the console before the console responds to input when
572 * there has been no input for some time.
574 #define MIN_TIMEOUT (10)
575 #define MAX_TIMEOUT (2000)
576 static u32 timeout
= MIN_TIMEOUT
;
578 #define HVC_POLL_READ 0x00000001
579 #define HVC_POLL_WRITE 0x00000002
581 int hvc_poll(struct hvc_struct
*hp
)
583 struct tty_struct
*tty
;
584 int i
, n
, poll_mask
= 0;
585 char buf
[N_INBUF
] __ALIGNED__
;
588 int written_total
= 0;
590 spin_lock_irqsave(&hp
->lock
, flags
);
592 /* Push pending writes */
593 if (hp
->n_outbuf
> 0)
594 written_total
= hvc_push(hp
);
596 /* Reschedule us if still some write pending */
597 if (hp
->n_outbuf
> 0) {
598 poll_mask
|= HVC_POLL_WRITE
;
599 /* If hvc_push() was not able to write, sleep a few msecs */
600 timeout
= (written_total
) ? 0 : MIN_TIMEOUT
;
603 /* No tty attached, just skip */
604 tty
= tty_kref_get(hp
->tty
);
608 /* Now check if we can get data (are we throttled ?) */
609 if (test_bit(TTY_THROTTLED
, &tty
->flags
))
612 /* If we aren't notifier driven and aren't throttled, we always
613 * request a reschedule
615 if (!hp
->irq_requested
)
616 poll_mask
|= HVC_POLL_READ
;
618 /* Read data if any */
620 int count
= tty_buffer_request_room(tty
, N_INBUF
);
622 /* If flip is full, just reschedule a later read */
624 poll_mask
|= HVC_POLL_READ
;
628 n
= hp
->ops
->get_chars(hp
->vtermno
, buf
, count
);
630 /* Hangup the tty when disconnected from host */
632 spin_unlock_irqrestore(&hp
->lock
, flags
);
634 spin_lock_irqsave(&hp
->lock
, flags
);
635 } else if ( n
== -EAGAIN
) {
637 * Some back-ends can only ensure a certain min
638 * num of bytes read, which may be > 'count'.
639 * Let the tty clear the flip buff to make room.
641 poll_mask
|= HVC_POLL_READ
;
645 for (i
= 0; i
< n
; ++i
) {
646 #ifdef CONFIG_MAGIC_SYSRQ
647 if (hp
->index
== hvc_console
.index
) {
648 /* Handle the SysRq Hack */
649 /* XXX should support a sequence */
650 if (buf
[i
] == '\x0f') { /* ^O */
651 /* if ^O is pressed again, reset
652 * sysrq_pressed and flip ^O char */
653 sysrq_pressed
= !sysrq_pressed
;
656 } else if (sysrq_pressed
) {
657 handle_sysrq(buf
[i
]);
662 #endif /* CONFIG_MAGIC_SYSRQ */
663 tty_insert_flip_char(tty
, buf
[i
], 0);
669 /* Wakeup write queue if necessary */
675 spin_unlock_irqrestore(&hp
->lock
, flags
);
678 /* Activity is occurring, so reset the polling backoff value to
679 a minimum for performance. */
680 timeout
= MIN_TIMEOUT
;
682 tty_flip_buffer_push(tty
);
689 EXPORT_SYMBOL_GPL(hvc_poll
);
692 * __hvc_resize() - Update terminal window size information.
693 * @hp: HVC console pointer
694 * @ws: Terminal window size structure
696 * Stores the specified window size information in the hvc structure of @hp.
697 * The function schedule the tty resize update.
699 * Locking: Locking free; the function MUST be called holding hp->lock
701 void __hvc_resize(struct hvc_struct
*hp
, struct winsize ws
)
704 schedule_work(&hp
->tty_resize
);
706 EXPORT_SYMBOL_GPL(__hvc_resize
);
709 * This kthread is either polling or interrupt driven. This is determined by
710 * calling hvc_poll() who determines whether a console adapter support
713 static int khvcd(void *unused
)
716 struct hvc_struct
*hp
;
724 if (!cpus_are_in_xmon()) {
725 spin_lock(&hvc_structs_lock
);
726 list_for_each_entry(hp
, &hvc_structs
, next
) {
727 poll_mask
|= hvc_poll(hp
);
729 spin_unlock(&hvc_structs_lock
);
731 poll_mask
|= HVC_POLL_READ
;
734 set_current_state(TASK_INTERRUPTIBLE
);
739 if (timeout
< MAX_TIMEOUT
)
740 timeout
+= (timeout
>> 6) + 1;
742 msleep_interruptible(timeout
);
745 __set_current_state(TASK_RUNNING
);
746 } while (!kthread_should_stop());
751 static int hvc_tiocmget(struct tty_struct
*tty
)
753 struct hvc_struct
*hp
= tty
->driver_data
;
755 if (!hp
|| !hp
->ops
->tiocmget
)
757 return hp
->ops
->tiocmget(hp
);
760 static int hvc_tiocmset(struct tty_struct
*tty
,
761 unsigned int set
, unsigned int clear
)
763 struct hvc_struct
*hp
= tty
->driver_data
;
765 if (!hp
|| !hp
->ops
->tiocmset
)
767 return hp
->ops
->tiocmset(hp
, set
, clear
);
770 #ifdef CONFIG_CONSOLE_POLL
771 int hvc_poll_init(struct tty_driver
*driver
, int line
, char *options
)
776 static int hvc_poll_get_char(struct tty_driver
*driver
, int line
)
778 struct tty_struct
*tty
= driver
->ttys
[0];
779 struct hvc_struct
*hp
= tty
->driver_data
;
783 n
= hp
->ops
->get_chars(hp
->vtermno
, &ch
, 1);
791 static void hvc_poll_put_char(struct tty_driver
*driver
, int line
, char ch
)
793 struct tty_struct
*tty
= driver
->ttys
[0];
794 struct hvc_struct
*hp
= tty
->driver_data
;
798 n
= hp
->ops
->put_chars(hp
->vtermno
, &ch
, 1);
803 static const struct tty_operations hvc_ops
= {
807 .hangup
= hvc_hangup
,
808 .unthrottle
= hvc_unthrottle
,
809 .write_room
= hvc_write_room
,
810 .chars_in_buffer
= hvc_chars_in_buffer
,
811 .tiocmget
= hvc_tiocmget
,
812 .tiocmset
= hvc_tiocmset
,
813 #ifdef CONFIG_CONSOLE_POLL
814 .poll_init
= hvc_poll_init
,
815 .poll_get_char
= hvc_poll_get_char
,
816 .poll_put_char
= hvc_poll_put_char
,
820 struct hvc_struct
*hvc_alloc(uint32_t vtermno
, int data
,
821 const struct hv_ops
*ops
,
824 struct hvc_struct
*hp
;
827 /* We wait until a driver actually comes along */
829 int err
= hvc_init();
834 hp
= kzalloc(ALIGN(sizeof(*hp
), sizeof(long)) + outbuf_size
,
837 return ERR_PTR(-ENOMEM
);
839 hp
->vtermno
= vtermno
;
842 hp
->outbuf_size
= outbuf_size
;
843 hp
->outbuf
= &((char *)hp
)[ALIGN(sizeof(*hp
), sizeof(long))];
845 kref_init(&hp
->kref
);
847 INIT_WORK(&hp
->tty_resize
, hvc_set_winsz
);
848 spin_lock_init(&hp
->lock
);
849 spin_lock(&hvc_structs_lock
);
853 * see if this vterm id matches one registered for console.
855 for (i
=0; i
< MAX_NR_HVC_CONSOLES
; i
++)
856 if (vtermnos
[i
] == hp
->vtermno
&&
857 cons_ops
[i
] == hp
->ops
)
860 /* no matching slot, just use a counter */
861 if (i
>= MAX_NR_HVC_CONSOLES
)
866 list_add_tail(&(hp
->next
), &hvc_structs
);
867 spin_unlock(&hvc_structs_lock
);
871 EXPORT_SYMBOL_GPL(hvc_alloc
);
873 int hvc_remove(struct hvc_struct
*hp
)
876 struct tty_struct
*tty
;
878 spin_lock_irqsave(&hp
->lock
, flags
);
879 tty
= tty_kref_get(hp
->tty
);
881 if (hp
->index
< MAX_NR_HVC_CONSOLES
)
882 vtermnos
[hp
->index
] = -1;
884 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
886 spin_unlock_irqrestore(&hp
->lock
, flags
);
889 * We 'put' the instance that was grabbed when the kref instance
890 * was initialized using kref_init(). Let the last holder of this
891 * kref cause it to be removed, which will probably be the tty_vhangup
894 kref_put(&hp
->kref
, destroy_hvc_struct
);
897 * This function call will auto chain call hvc_hangup.
905 EXPORT_SYMBOL_GPL(hvc_remove
);
907 /* Driver initialization: called as soon as someone uses hvc_alloc(). */
908 static int hvc_init(void)
910 struct tty_driver
*drv
;
913 /* We need more than hvc_count adapters due to hotplug additions. */
914 drv
= alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS
);
920 drv
->owner
= THIS_MODULE
;
921 drv
->driver_name
= "hvc";
923 drv
->major
= HVC_MAJOR
;
924 drv
->minor_start
= HVC_MINOR
;
925 drv
->type
= TTY_DRIVER_TYPE_SYSTEM
;
926 drv
->init_termios
= tty_std_termios
;
927 drv
->flags
= TTY_DRIVER_REAL_RAW
| TTY_DRIVER_RESET_TERMIOS
;
928 tty_set_operations(drv
, &hvc_ops
);
930 /* Always start the kthread because there can be hotplug vty adapters
932 hvc_task
= kthread_run(khvcd
, NULL
, "khvcd");
933 if (IS_ERR(hvc_task
)) {
934 printk(KERN_ERR
"Couldn't create kthread for console.\n");
935 err
= PTR_ERR(hvc_task
);
939 err
= tty_register_driver(drv
);
941 printk(KERN_ERR
"Couldn't register hvc console driver\n");
946 * Make sure tty is fully registered before allowing it to be
947 * found by hvc_console_device.
954 kthread_stop(hvc_task
);
962 /* This isn't particularly necessary due to this being a console driver
963 * but it is nice to be thorough.
965 static void __exit
hvc_exit(void)
968 kthread_stop(hvc_task
);
970 tty_unregister_driver(hvc_driver
);
971 /* return tty_struct instances allocated in hvc_init(). */
972 put_tty_driver(hvc_driver
);
973 unregister_console(&hvc_console
);
976 module_exit(hvc_exit
);