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/init.h>
33 #include <linux/major.h>
34 #include <linux/atomic.h>
35 #include <linux/sysrq.h>
36 #include <linux/tty.h>
37 #include <linux/tty_flip.h>
38 #include <linux/sched.h>
39 #include <linux/spinlock.h>
40 #include <linux/delay.h>
41 #include <linux/freezer.h>
42 #include <linux/slab.h>
43 #include <linux/serial_core.h>
45 #include <asm/uaccess.h>
47 #include "hvc_console.h"
53 * Wait this long per iteration while trying to push buffered data to the
54 * hypervisor before allowing the tty to complete a close operation.
56 #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
59 * These sizes are most efficient for vio, because they are the
60 * native transfer size. We could make them selectable in the
61 * future to better deal with backends that want other buffer sizes.
66 #define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
68 static struct tty_driver *hvc_driver;
69 static struct task_struct *hvc_task;
71 /* Picks up late kicks after list walk but before schedule() */
72 static int hvc_kicked;
74 /* hvc_init is triggered from hvc_alloc, i.e. only when actually used */
75 static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1);
77 static int hvc_init(void);
79 #ifdef CONFIG_MAGIC_SYSRQ
80 static int sysrq_pressed;
83 /* dynamic list of hvc_struct instances */
84 static LIST_HEAD(hvc_structs);
87 * Protect the list of hvc_struct instances from inserts and removals during
90 static DEFINE_SPINLOCK(hvc_structs_lock);
92 /* Mutex to serialize hvc_open */
93 static DEFINE_MUTEX(hvc_open_mutex);
95 * This value is used to assign a tty->index value to a hvc_struct based
96 * upon order of exposure via hvc_probe(), when we can not match it to
97 * a console candidate registered with hvc_instantiate().
99 static int last_hvc = -1;
102 * Do not call this function with either the hvc_structs_lock or the hvc_struct
103 * lock held. If successful, this function increments the kref reference
104 * count against the target hvc_struct so it should be released when finished.
106 static struct hvc_struct *hvc_get_by_index(int index)
108 struct hvc_struct *hp;
111 spin_lock(&hvc_structs_lock);
113 list_for_each_entry(hp, &hvc_structs, next) {
114 spin_lock_irqsave(&hp->lock, flags);
115 if (hp->index == index) {
116 tty_port_get(&hp->port);
117 spin_unlock_irqrestore(&hp->lock, flags);
118 spin_unlock(&hvc_structs_lock);
121 spin_unlock_irqrestore(&hp->lock, flags);
125 spin_unlock(&hvc_structs_lock);
131 * Initial console vtermnos for console API usage prior to full console
132 * initialization. Any vty adapter outside this range will not have usable
133 * console interfaces but can still be used as a tty device. This has to be
134 * static because kmalloc will not work during early console init.
136 static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
137 static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
138 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
141 * Console APIs, NOT TTY. These APIs are available immediately when
142 * hvc_console_setup() finds adapters.
145 static void hvc_console_print(struct console *co, const char *b,
148 char c[N_OUTBUF] __ALIGNED__;
149 unsigned i = 0, n = 0;
150 int r, donecr = 0, index = co->index;
152 /* Console access attempt outside of acceptable console range. */
153 if (index >= MAX_NR_HVC_CONSOLES)
156 /* This console adapter was removed so it is not usable. */
157 if (vtermnos[index] == -1)
160 while (count > 0 || i > 0) {
161 if (count > 0 && i < sizeof(c)) {
162 if (b[n] == '\n' && !donecr) {
171 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
173 /* throw away characters on error
174 * but spin in case of -EAGAIN */
186 static struct tty_driver *hvc_console_device(struct console *c, int *index)
188 if (vtermnos[c->index] == -1)
195 static int hvc_console_setup(struct console *co, char *options)
197 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
200 if (vtermnos[co->index] == -1)
206 static struct console hvc_console = {
208 .write = hvc_console_print,
209 .device = hvc_console_device,
210 .setup = hvc_console_setup,
211 .flags = CON_PRINTBUFFER,
216 * Early console initialization. Precedes driver initialization.
218 * (1) we are first, and the user specified another driver
219 * -- index will remain -1
220 * (2) we are first and the user specified no driver
221 * -- index will be set to 0, then we will fail setup.
222 * (3) we are first and the user specified our driver
223 * -- index will be set to user specified driver, and we will fail
224 * (4) we are after driver, and this initcall will register us
225 * -- if the user didn't specify a driver then the console will match
227 * Note that for cases 2 and 3, we will match later when the io driver
228 * calls hvc_instantiate() and call register again.
230 static int __init hvc_console_init(void)
232 register_console(&hvc_console);
235 console_initcall(hvc_console_init);
237 /* callback when the kboject ref count reaches zero. */
238 static void hvc_port_destruct(struct tty_port *port)
240 struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
243 spin_lock(&hvc_structs_lock);
245 spin_lock_irqsave(&hp->lock, flags);
246 list_del(&(hp->next));
247 spin_unlock_irqrestore(&hp->lock, flags);
249 spin_unlock(&hvc_structs_lock);
254 static void hvc_check_console(int index)
256 /* Already enabled, bail out */
257 if (hvc_console.flags & CON_ENABLED)
260 /* If this index is what the user requested, then register
261 * now (setup won't fail at this point). It's ok to just
262 * call register again if previously .setup failed.
264 if (index == hvc_console.index)
265 register_console(&hvc_console);
269 * hvc_instantiate() is an early console discovery method which locates
270 * consoles * prior to the vio subsystem discovering them. Hotplugged
271 * vty adapters do NOT get an hvc_instantiate() callback since they
272 * appear after early console init.
274 int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
276 struct hvc_struct *hp;
278 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
281 if (vtermnos[index] != -1)
284 /* make sure no no tty has been registered in this index */
285 hp = hvc_get_by_index(index);
287 tty_port_put(&hp->port);
291 vtermnos[index] = vtermno;
292 cons_ops[index] = ops;
294 /* check if we need to re-register the kernel console */
295 hvc_check_console(index);
299 EXPORT_SYMBOL_GPL(hvc_instantiate);
301 /* Wake the sleeping khvcd */
305 wake_up_process(hvc_task);
307 EXPORT_SYMBOL_GPL(hvc_kick);
309 static void hvc_unthrottle(struct tty_struct *tty)
314 static int hvc_install(struct tty_driver *driver, struct tty_struct *tty)
316 struct hvc_struct *hp;
319 /* Auto increments kref reference if found. */
320 hp = hvc_get_by_index(tty->index);
324 tty->driver_data = hp;
326 rc = tty_port_install(&hp->port, driver, tty);
328 tty_port_put(&hp->port);
333 * The TTY interface won't be used until after the vio layer has exposed the vty
334 * adapter to the kernel.
336 static int hvc_open(struct tty_struct *tty, struct file * filp)
338 struct hvc_struct *hp;
342 mutex_lock(&hvc_open_mutex);
344 hp = tty->driver_data;
350 spin_lock_irqsave(&hp->port.lock, flags);
351 /* Check and then increment for fast path open. */
352 if (hp->port.count++ > 0) {
353 spin_unlock_irqrestore(&hp->port.lock, flags);
356 } /* else count == 0 */
357 spin_unlock_irqrestore(&hp->port.lock, flags);
359 tty_port_tty_set(&hp->port, tty);
361 if (hp->ops->notifier_add)
362 rc = hp->ops->notifier_add(hp, hp->data);
365 * If the notifier fails we return an error. The tty layer
366 * will call hvc_close() after a failed open but we don't want to clean
367 * up there so we'll clean up here and clear out the previously set
368 * tty fields and return the kref reference.
371 tty_port_tty_set(&hp->port, NULL);
372 tty->driver_data = NULL;
373 tty_port_put(&hp->port);
374 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
376 /* We are ready... raise DTR/RTS */
378 if (hp->ops->dtr_rts)
379 hp->ops->dtr_rts(hp, 1);
381 /* Force wakeup of the polling thread */
385 mutex_unlock(&hvc_open_mutex);
389 static void hvc_close(struct tty_struct *tty, struct file * filp)
391 struct hvc_struct *hp;
394 if (tty_hung_up_p(filp))
398 * No driver_data means that this close was issued after a failed
399 * hvc_open by the tty layer's release_dev() function and we can just
400 * exit cleanly because the kref reference wasn't made.
402 if (!tty->driver_data)
405 hp = tty->driver_data;
407 spin_lock_irqsave(&hp->port.lock, flags);
409 if (--hp->port.count == 0) {
410 spin_unlock_irqrestore(&hp->port.lock, flags);
411 /* We are done with the tty pointer now. */
412 tty_port_tty_set(&hp->port, NULL);
415 if (hp->ops->dtr_rts)
416 hp->ops->dtr_rts(hp, 0);
418 if (hp->ops->notifier_del)
419 hp->ops->notifier_del(hp, hp->data);
421 /* cancel pending tty resize work */
422 cancel_work_sync(&hp->tty_resize);
425 * Chain calls chars_in_buffer() and returns immediately if
426 * there is no buffered data otherwise sleeps on a wait queue
427 * waking periodically to check chars_in_buffer().
429 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
431 if (hp->port.count < 0)
432 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
433 hp->vtermno, hp->port.count);
434 spin_unlock_irqrestore(&hp->port.lock, flags);
438 static void hvc_cleanup(struct tty_struct *tty)
440 struct hvc_struct *hp = tty->driver_data;
442 tty_port_put(&hp->port);
445 static void hvc_hangup(struct tty_struct *tty)
447 struct hvc_struct *hp = tty->driver_data;
453 /* cancel pending tty resize work */
454 cancel_work_sync(&hp->tty_resize);
456 spin_lock_irqsave(&hp->port.lock, flags);
459 * The N_TTY line discipline has problems such that in a close vs
460 * open->hangup case this can be called after the final close so prevent
461 * that from happening for now.
463 if (hp->port.count <= 0) {
464 spin_unlock_irqrestore(&hp->port.lock, flags);
469 spin_unlock_irqrestore(&hp->port.lock, flags);
470 tty_port_tty_set(&hp->port, NULL);
474 if (hp->ops->notifier_hangup)
475 hp->ops->notifier_hangup(hp, hp->data);
479 * Push buffered characters whether they were just recently buffered or waiting
480 * on a blocked hypervisor. Call this function with hp->lock held.
482 static int hvc_push(struct hvc_struct *hp)
486 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
488 if (n == 0 || n == -EAGAIN) {
492 /* throw away output on error; this happens when
493 there is no session connected to the vterm. */
497 if (hp->n_outbuf > 0)
498 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
505 static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
507 struct hvc_struct *hp = tty->driver_data;
509 int rsize, written = 0;
511 /* This write was probably executed during a tty close. */
515 /* FIXME what's this (unprotected) check for? */
516 if (hp->port.count <= 0)
519 spin_lock_irqsave(&hp->lock, flags);
521 /* Push pending writes */
522 if (hp->n_outbuf > 0)
525 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
528 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
531 hp->n_outbuf += rsize;
535 spin_unlock_irqrestore(&hp->lock, flags);
538 * Racy, but harmless, kick thread if there is still pending data.
547 * hvc_set_winsz() - Resize the hvc tty terminal window.
548 * @work: work structure.
550 * The routine shall not be called within an atomic context because it
555 static void hvc_set_winsz(struct work_struct *work)
557 struct hvc_struct *hp;
558 unsigned long hvc_flags;
559 struct tty_struct *tty;
562 hp = container_of(work, struct hvc_struct, tty_resize);
564 tty = tty_port_tty_get(&hp->port);
568 spin_lock_irqsave(&hp->lock, hvc_flags);
570 spin_unlock_irqrestore(&hp->lock, hvc_flags);
572 tty_do_resize(tty, &ws);
577 * This is actually a contract between the driver and the tty layer outlining
578 * how much write room the driver can guarantee will be sent OR BUFFERED. This
579 * driver MUST honor the return value.
581 static int hvc_write_room(struct tty_struct *tty)
583 struct hvc_struct *hp = tty->driver_data;
588 return hp->outbuf_size - hp->n_outbuf;
591 static int hvc_chars_in_buffer(struct tty_struct *tty)
593 struct hvc_struct *hp = tty->driver_data;
601 * timeout will vary between the MIN and MAX values defined here. By default
602 * and during console activity we will use a default MIN_TIMEOUT of 10. When
603 * the console is idle, we increase the timeout value on each pass through
604 * msleep until we reach the max. This may be noticeable as a brief (average
605 * one second) delay on the console before the console responds to input when
606 * there has been no input for some time.
608 #define MIN_TIMEOUT (10)
609 #define MAX_TIMEOUT (2000)
610 static u32 timeout = MIN_TIMEOUT;
612 #define HVC_POLL_READ 0x00000001
613 #define HVC_POLL_WRITE 0x00000002
615 int hvc_poll(struct hvc_struct *hp)
617 struct tty_struct *tty;
618 int i, n, poll_mask = 0;
619 char buf[N_INBUF] __ALIGNED__;
622 int written_total = 0;
624 spin_lock_irqsave(&hp->lock, flags);
626 /* Push pending writes */
627 if (hp->n_outbuf > 0)
628 written_total = hvc_push(hp);
630 /* Reschedule us if still some write pending */
631 if (hp->n_outbuf > 0) {
632 poll_mask |= HVC_POLL_WRITE;
633 /* If hvc_push() was not able to write, sleep a few msecs */
634 timeout = (written_total) ? 0 : MIN_TIMEOUT;
637 /* No tty attached, just skip */
638 tty = tty_port_tty_get(&hp->port);
642 /* Now check if we can get data (are we throttled ?) */
643 if (test_bit(TTY_THROTTLED, &tty->flags))
646 /* If we aren't notifier driven and aren't throttled, we always
647 * request a reschedule
649 if (!hp->irq_requested)
650 poll_mask |= HVC_POLL_READ;
652 /* Read data if any */
654 int count = tty_buffer_request_room(&hp->port, N_INBUF);
656 /* If flip is full, just reschedule a later read */
658 poll_mask |= HVC_POLL_READ;
662 n = hp->ops->get_chars(hp->vtermno, buf, count);
664 /* Hangup the tty when disconnected from host */
666 spin_unlock_irqrestore(&hp->lock, flags);
668 spin_lock_irqsave(&hp->lock, flags);
669 } else if ( n == -EAGAIN ) {
671 * Some back-ends can only ensure a certain min
672 * num of bytes read, which may be > 'count'.
673 * Let the tty clear the flip buff to make room.
675 poll_mask |= HVC_POLL_READ;
679 for (i = 0; i < n; ++i) {
680 #ifdef CONFIG_MAGIC_SYSRQ
681 if (hp->index == hvc_console.index) {
682 /* Handle the SysRq Hack */
683 /* XXX should support a sequence */
684 if (buf[i] == '\x0f') { /* ^O */
685 /* if ^O is pressed again, reset
686 * sysrq_pressed and flip ^O char */
687 sysrq_pressed = !sysrq_pressed;
690 } else if (sysrq_pressed) {
691 handle_sysrq(buf[i]);
696 #endif /* CONFIG_MAGIC_SYSRQ */
697 tty_insert_flip_char(&hp->port, buf[i], 0);
703 /* Wakeup write queue if necessary */
709 spin_unlock_irqrestore(&hp->lock, flags);
712 /* Activity is occurring, so reset the polling backoff value to
713 a minimum for performance. */
714 timeout = MIN_TIMEOUT;
716 tty_flip_buffer_push(&hp->port);
722 EXPORT_SYMBOL_GPL(hvc_poll);
725 * __hvc_resize() - Update terminal window size information.
726 * @hp: HVC console pointer
727 * @ws: Terminal window size structure
729 * Stores the specified window size information in the hvc structure of @hp.
730 * The function schedule the tty resize update.
732 * Locking: Locking free; the function MUST be called holding hp->lock
734 void __hvc_resize(struct hvc_struct *hp, struct winsize ws)
737 schedule_work(&hp->tty_resize);
739 EXPORT_SYMBOL_GPL(__hvc_resize);
742 * This kthread is either polling or interrupt driven. This is determined by
743 * calling hvc_poll() who determines whether a console adapter support
746 static int khvcd(void *unused)
749 struct hvc_struct *hp;
757 if (!cpus_are_in_xmon()) {
758 spin_lock(&hvc_structs_lock);
759 list_for_each_entry(hp, &hvc_structs, next) {
760 poll_mask |= hvc_poll(hp);
762 spin_unlock(&hvc_structs_lock);
764 poll_mask |= HVC_POLL_READ;
767 set_current_state(TASK_INTERRUPTIBLE);
772 unsigned long j_timeout;
774 if (timeout < MAX_TIMEOUT)
775 timeout += (timeout >> 6) + 1;
778 * We don't use msleep_interruptible otherwise
779 * "kick" will fail to wake us up
781 j_timeout = msecs_to_jiffies(timeout) + 1;
782 schedule_timeout_interruptible(j_timeout);
785 __set_current_state(TASK_RUNNING);
786 } while (!kthread_should_stop());
791 static int hvc_tiocmget(struct tty_struct *tty)
793 struct hvc_struct *hp = tty->driver_data;
795 if (!hp || !hp->ops->tiocmget)
797 return hp->ops->tiocmget(hp);
800 static int hvc_tiocmset(struct tty_struct *tty,
801 unsigned int set, unsigned int clear)
803 struct hvc_struct *hp = tty->driver_data;
805 if (!hp || !hp->ops->tiocmset)
807 return hp->ops->tiocmset(hp, set, clear);
810 #ifdef CONFIG_CONSOLE_POLL
811 static int hvc_poll_init(struct tty_driver *driver, int line, char *options)
816 static int hvc_poll_get_char(struct tty_driver *driver, int line)
818 struct tty_struct *tty = driver->ttys[0];
819 struct hvc_struct *hp = tty->driver_data;
823 n = hp->ops->get_chars(hp->vtermno, &ch, 1);
831 static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)
833 struct tty_struct *tty = driver->ttys[0];
834 struct hvc_struct *hp = tty->driver_data;
838 n = hp->ops->put_chars(hp->vtermno, &ch, 1);
843 static const struct tty_operations hvc_ops = {
844 .install = hvc_install,
847 .cleanup = hvc_cleanup,
849 .hangup = hvc_hangup,
850 .unthrottle = hvc_unthrottle,
851 .write_room = hvc_write_room,
852 .chars_in_buffer = hvc_chars_in_buffer,
853 .tiocmget = hvc_tiocmget,
854 .tiocmset = hvc_tiocmset,
855 #ifdef CONFIG_CONSOLE_POLL
856 .poll_init = hvc_poll_init,
857 .poll_get_char = hvc_poll_get_char,
858 .poll_put_char = hvc_poll_put_char,
862 static const struct tty_port_operations hvc_port_ops = {
863 .destruct = hvc_port_destruct,
866 struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
867 const struct hv_ops *ops,
870 struct hvc_struct *hp;
873 /* We wait until a driver actually comes along */
874 if (atomic_inc_not_zero(&hvc_needs_init)) {
875 int err = hvc_init();
880 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
883 return ERR_PTR(-ENOMEM);
885 hp->vtermno = vtermno;
888 hp->outbuf_size = outbuf_size;
889 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
891 tty_port_init(&hp->port);
892 hp->port.ops = &hvc_port_ops;
894 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
895 spin_lock_init(&hp->lock);
896 spin_lock(&hvc_structs_lock);
900 * see if this vterm id matches one registered for console.
902 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
903 if (vtermnos[i] == hp->vtermno &&
904 cons_ops[i] == hp->ops)
907 if (i >= MAX_NR_HVC_CONSOLES) {
909 /* find 'empty' slot for console */
910 for (i = 0; i < MAX_NR_HVC_CONSOLES && vtermnos[i] != -1; i++) {
913 /* no matching slot, just use a counter */
914 if (i == MAX_NR_HVC_CONSOLES)
915 i = ++last_hvc + MAX_NR_HVC_CONSOLES;
919 if (i < MAX_NR_HVC_CONSOLES) {
921 vtermnos[i] = vtermno;
924 list_add_tail(&(hp->next), &hvc_structs);
925 spin_unlock(&hvc_structs_lock);
927 /* check if we need to re-register the kernel console */
928 hvc_check_console(i);
932 EXPORT_SYMBOL_GPL(hvc_alloc);
934 int hvc_remove(struct hvc_struct *hp)
937 struct tty_struct *tty;
939 tty = tty_port_tty_get(&hp->port);
941 spin_lock_irqsave(&hp->lock, flags);
942 if (hp->index < MAX_NR_HVC_CONSOLES) {
944 vtermnos[hp->index] = -1;
945 cons_ops[hp->index] = NULL;
949 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
951 spin_unlock_irqrestore(&hp->lock, flags);
954 * We 'put' the instance that was grabbed when the kref instance
955 * was initialized using kref_init(). Let the last holder of this
956 * kref cause it to be removed, which will probably be the tty_vhangup
959 tty_port_put(&hp->port);
962 * This function call will auto chain call hvc_hangup.
970 EXPORT_SYMBOL_GPL(hvc_remove);
972 /* Driver initialization: called as soon as someone uses hvc_alloc(). */
973 static int hvc_init(void)
975 struct tty_driver *drv;
978 /* We need more than hvc_count adapters due to hotplug additions. */
979 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
985 drv->driver_name = "hvc";
987 drv->major = HVC_MAJOR;
988 drv->minor_start = HVC_MINOR;
989 drv->type = TTY_DRIVER_TYPE_SYSTEM;
990 drv->init_termios = tty_std_termios;
991 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
992 tty_set_operations(drv, &hvc_ops);
994 /* Always start the kthread because there can be hotplug vty adapters
996 hvc_task = kthread_run(khvcd, NULL, "khvcd");
997 if (IS_ERR(hvc_task)) {
998 printk(KERN_ERR "Couldn't create kthread for console.\n");
999 err = PTR_ERR(hvc_task);
1003 err = tty_register_driver(drv);
1005 printk(KERN_ERR "Couldn't register hvc console driver\n");
1010 * Make sure tty is fully registered before allowing it to be
1011 * found by hvc_console_device.
1018 kthread_stop(hvc_task);
1021 put_tty_driver(drv);