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/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);
93 * This value is used to assign a tty->index value to a hvc_struct based
94 * upon order of exposure via hvc_probe(), when we can not match it to
95 * a console candidate registered with hvc_instantiate().
97 static int last_hvc = -1;
100 * Do not call this function with either the hvc_structs_lock or the hvc_struct
101 * lock held. If successful, this function increments the kref reference
102 * count against the target hvc_struct so it should be released when finished.
104 static struct hvc_struct *hvc_get_by_index(int index)
106 struct hvc_struct *hp;
109 spin_lock(&hvc_structs_lock);
111 list_for_each_entry(hp, &hvc_structs, next) {
112 spin_lock_irqsave(&hp->lock, flags);
113 if (hp->index == index) {
114 tty_port_get(&hp->port);
115 spin_unlock_irqrestore(&hp->lock, flags);
116 spin_unlock(&hvc_structs_lock);
119 spin_unlock_irqrestore(&hp->lock, flags);
123 spin_unlock(&hvc_structs_lock);
129 * Initial console vtermnos for console API usage prior to full console
130 * initialization. Any vty adapter outside this range will not have usable
131 * console interfaces but can still be used as a tty device. This has to be
132 * static because kmalloc will not work during early console init.
134 static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
135 static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
136 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
139 * Console APIs, NOT TTY. These APIs are available immediately when
140 * hvc_console_setup() finds adapters.
143 static void hvc_console_print(struct console *co, const char *b,
146 char c[N_OUTBUF] __ALIGNED__;
147 unsigned i = 0, n = 0;
148 int r, donecr = 0, index = co->index;
150 /* Console access attempt outside of acceptable console range. */
151 if (index >= MAX_NR_HVC_CONSOLES)
154 /* This console adapter was removed so it is not usable. */
155 if (vtermnos[index] == -1)
158 while (count > 0 || i > 0) {
159 if (count > 0 && i < sizeof(c)) {
160 if (b[n] == '\n' && !donecr) {
169 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
171 /* throw away characters on error
172 * but spin in case of -EAGAIN */
184 static struct tty_driver *hvc_console_device(struct console *c, int *index)
186 if (vtermnos[c->index] == -1)
193 static int hvc_console_setup(struct console *co, char *options)
195 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
198 if (vtermnos[co->index] == -1)
204 static struct console hvc_console = {
206 .write = hvc_console_print,
207 .device = hvc_console_device,
208 .setup = hvc_console_setup,
209 .flags = CON_PRINTBUFFER,
214 * Early console initialization. Precedes driver initialization.
216 * (1) we are first, and the user specified another driver
217 * -- index will remain -1
218 * (2) we are first and the user specified no driver
219 * -- index will be set to 0, then we will fail setup.
220 * (3) we are first and the user specified our driver
221 * -- index will be set to user specified driver, and we will fail
222 * (4) we are after driver, and this initcall will register us
223 * -- if the user didn't specify a driver then the console will match
225 * Note that for cases 2 and 3, we will match later when the io driver
226 * calls hvc_instantiate() and call register again.
228 static int __init hvc_console_init(void)
230 register_console(&hvc_console);
233 console_initcall(hvc_console_init);
235 /* callback when the kboject ref count reaches zero. */
236 static void hvc_port_destruct(struct tty_port *port)
238 struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
241 spin_lock(&hvc_structs_lock);
243 spin_lock_irqsave(&hp->lock, flags);
244 list_del(&(hp->next));
245 spin_unlock_irqrestore(&hp->lock, flags);
247 spin_unlock(&hvc_structs_lock);
252 static void hvc_check_console(int index)
254 /* Already enabled, bail out */
255 if (hvc_console.flags & CON_ENABLED)
258 /* If this index is what the user requested, then register
259 * now (setup won't fail at this point). It's ok to just
260 * call register again if previously .setup failed.
262 if (index == hvc_console.index)
263 register_console(&hvc_console);
267 * hvc_instantiate() is an early console discovery method which locates
268 * consoles * prior to the vio subsystem discovering them. Hotplugged
269 * vty adapters do NOT get an hvc_instantiate() callback since they
270 * appear after early console init.
272 int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
274 struct hvc_struct *hp;
276 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
279 if (vtermnos[index] != -1)
282 /* make sure no no tty has been registered in this index */
283 hp = hvc_get_by_index(index);
285 tty_port_put(&hp->port);
289 vtermnos[index] = vtermno;
290 cons_ops[index] = ops;
292 /* reserve all indices up to and including this index */
293 if (last_hvc < index)
296 /* check if we need to re-register the kernel console */
297 hvc_check_console(index);
301 EXPORT_SYMBOL_GPL(hvc_instantiate);
303 /* Wake the sleeping khvcd */
307 wake_up_process(hvc_task);
309 EXPORT_SYMBOL_GPL(hvc_kick);
311 static void hvc_unthrottle(struct tty_struct *tty)
316 static int hvc_install(struct tty_driver *driver, struct tty_struct *tty)
318 struct hvc_struct *hp;
321 /* Auto increments kref reference if found. */
322 if (!(hp = hvc_get_by_index(tty->index)))
325 tty->driver_data = hp;
327 rc = tty_port_install(&hp->port, driver, tty);
329 tty_port_put(&hp->port);
334 * The TTY interface won't be used until after the vio layer has exposed the vty
335 * adapter to the kernel.
337 static int hvc_open(struct tty_struct *tty, struct file * filp)
339 struct hvc_struct *hp = tty->driver_data;
343 spin_lock_irqsave(&hp->port.lock, flags);
344 /* Check and then increment for fast path open. */
345 if (hp->port.count++ > 0) {
346 spin_unlock_irqrestore(&hp->port.lock, flags);
349 } /* else count == 0 */
350 spin_unlock_irqrestore(&hp->port.lock, flags);
352 tty_port_tty_set(&hp->port, tty);
354 if (hp->ops->notifier_add)
355 rc = hp->ops->notifier_add(hp, hp->data);
358 * If the notifier fails we return an error. The tty layer
359 * will call hvc_close() after a failed open but we don't want to clean
360 * up there so we'll clean up here and clear out the previously set
361 * tty fields and return the kref reference.
364 tty_port_tty_set(&hp->port, NULL);
365 tty->driver_data = NULL;
366 tty_port_put(&hp->port);
367 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
369 /* Force wakeup of the polling thread */
375 static void hvc_close(struct tty_struct *tty, struct file * filp)
377 struct hvc_struct *hp;
380 if (tty_hung_up_p(filp))
384 * No driver_data means that this close was issued after a failed
385 * hvc_open by the tty layer's release_dev() function and we can just
386 * exit cleanly because the kref reference wasn't made.
388 if (!tty->driver_data)
391 hp = tty->driver_data;
393 spin_lock_irqsave(&hp->port.lock, flags);
395 if (--hp->port.count == 0) {
396 spin_unlock_irqrestore(&hp->port.lock, flags);
397 /* We are done with the tty pointer now. */
398 tty_port_tty_set(&hp->port, NULL);
400 if (hp->ops->notifier_del)
401 hp->ops->notifier_del(hp, hp->data);
403 /* cancel pending tty resize work */
404 cancel_work_sync(&hp->tty_resize);
407 * Chain calls chars_in_buffer() and returns immediately if
408 * there is no buffered data otherwise sleeps on a wait queue
409 * waking periodically to check chars_in_buffer().
411 tty_wait_until_sent_from_close(tty, HVC_CLOSE_WAIT);
413 if (hp->port.count < 0)
414 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
415 hp->vtermno, hp->port.count);
416 spin_unlock_irqrestore(&hp->port.lock, flags);
420 static void hvc_cleanup(struct tty_struct *tty)
422 struct hvc_struct *hp = tty->driver_data;
424 tty_port_put(&hp->port);
427 static void hvc_hangup(struct tty_struct *tty)
429 struct hvc_struct *hp = tty->driver_data;
435 /* cancel pending tty resize work */
436 cancel_work_sync(&hp->tty_resize);
438 spin_lock_irqsave(&hp->port.lock, flags);
441 * The N_TTY line discipline has problems such that in a close vs
442 * open->hangup case this can be called after the final close so prevent
443 * that from happening for now.
445 if (hp->port.count <= 0) {
446 spin_unlock_irqrestore(&hp->port.lock, flags);
451 spin_unlock_irqrestore(&hp->port.lock, flags);
452 tty_port_tty_set(&hp->port, NULL);
456 if (hp->ops->notifier_hangup)
457 hp->ops->notifier_hangup(hp, hp->data);
461 * Push buffered characters whether they were just recently buffered or waiting
462 * on a blocked hypervisor. Call this function with hp->lock held.
464 static int hvc_push(struct hvc_struct *hp)
468 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
470 if (n == 0 || n == -EAGAIN) {
474 /* throw away output on error; this happens when
475 there is no session connected to the vterm. */
479 if (hp->n_outbuf > 0)
480 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
487 static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
489 struct hvc_struct *hp = tty->driver_data;
491 int rsize, written = 0;
493 /* This write was probably executed during a tty close. */
497 /* FIXME what's this (unprotected) check for? */
498 if (hp->port.count <= 0)
501 spin_lock_irqsave(&hp->lock, flags);
503 /* Push pending writes */
504 if (hp->n_outbuf > 0)
507 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
510 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
513 hp->n_outbuf += rsize;
517 spin_unlock_irqrestore(&hp->lock, flags);
520 * Racy, but harmless, kick thread if there is still pending data.
529 * hvc_set_winsz() - Resize the hvc tty terminal window.
530 * @work: work structure.
532 * The routine shall not be called within an atomic context because it
537 static void hvc_set_winsz(struct work_struct *work)
539 struct hvc_struct *hp;
540 unsigned long hvc_flags;
541 struct tty_struct *tty;
544 hp = container_of(work, struct hvc_struct, tty_resize);
546 tty = tty_port_tty_get(&hp->port);
550 spin_lock_irqsave(&hp->lock, hvc_flags);
552 spin_unlock_irqrestore(&hp->lock, hvc_flags);
554 tty_do_resize(tty, &ws);
559 * This is actually a contract between the driver and the tty layer outlining
560 * how much write room the driver can guarantee will be sent OR BUFFERED. This
561 * driver MUST honor the return value.
563 static int hvc_write_room(struct tty_struct *tty)
565 struct hvc_struct *hp = tty->driver_data;
570 return hp->outbuf_size - hp->n_outbuf;
573 static int hvc_chars_in_buffer(struct tty_struct *tty)
575 struct hvc_struct *hp = tty->driver_data;
583 * timeout will vary between the MIN and MAX values defined here. By default
584 * and during console activity we will use a default MIN_TIMEOUT of 10. When
585 * the console is idle, we increase the timeout value on each pass through
586 * msleep until we reach the max. This may be noticeable as a brief (average
587 * one second) delay on the console before the console responds to input when
588 * there has been no input for some time.
590 #define MIN_TIMEOUT (10)
591 #define MAX_TIMEOUT (2000)
592 static u32 timeout = MIN_TIMEOUT;
594 #define HVC_POLL_READ 0x00000001
595 #define HVC_POLL_WRITE 0x00000002
597 int hvc_poll(struct hvc_struct *hp)
599 struct tty_struct *tty;
600 int i, n, poll_mask = 0;
601 char buf[N_INBUF] __ALIGNED__;
604 int written_total = 0;
606 spin_lock_irqsave(&hp->lock, flags);
608 /* Push pending writes */
609 if (hp->n_outbuf > 0)
610 written_total = hvc_push(hp);
612 /* Reschedule us if still some write pending */
613 if (hp->n_outbuf > 0) {
614 poll_mask |= HVC_POLL_WRITE;
615 /* If hvc_push() was not able to write, sleep a few msecs */
616 timeout = (written_total) ? 0 : MIN_TIMEOUT;
619 /* No tty attached, just skip */
620 tty = tty_port_tty_get(&hp->port);
624 /* Now check if we can get data (are we throttled ?) */
625 if (test_bit(TTY_THROTTLED, &tty->flags))
628 /* If we aren't notifier driven and aren't throttled, we always
629 * request a reschedule
631 if (!hp->irq_requested)
632 poll_mask |= HVC_POLL_READ;
634 /* Read data if any */
636 int count = tty_buffer_request_room(&hp->port, N_INBUF);
638 /* If flip is full, just reschedule a later read */
640 poll_mask |= HVC_POLL_READ;
644 n = hp->ops->get_chars(hp->vtermno, buf, count);
646 /* Hangup the tty when disconnected from host */
648 spin_unlock_irqrestore(&hp->lock, flags);
650 spin_lock_irqsave(&hp->lock, flags);
651 } else if ( n == -EAGAIN ) {
653 * Some back-ends can only ensure a certain min
654 * num of bytes read, which may be > 'count'.
655 * Let the tty clear the flip buff to make room.
657 poll_mask |= HVC_POLL_READ;
661 for (i = 0; i < n; ++i) {
662 #ifdef CONFIG_MAGIC_SYSRQ
663 if (hp->index == hvc_console.index) {
664 /* Handle the SysRq Hack */
665 /* XXX should support a sequence */
666 if (buf[i] == '\x0f') { /* ^O */
667 /* if ^O is pressed again, reset
668 * sysrq_pressed and flip ^O char */
669 sysrq_pressed = !sysrq_pressed;
672 } else if (sysrq_pressed) {
673 handle_sysrq(buf[i]);
678 #endif /* CONFIG_MAGIC_SYSRQ */
679 tty_insert_flip_char(&hp->port, buf[i], 0);
685 /* Wakeup write queue if necessary */
691 spin_unlock_irqrestore(&hp->lock, flags);
694 /* Activity is occurring, so reset the polling backoff value to
695 a minimum for performance. */
696 timeout = MIN_TIMEOUT;
698 tty_flip_buffer_push(&hp->port);
704 EXPORT_SYMBOL_GPL(hvc_poll);
707 * __hvc_resize() - Update terminal window size information.
708 * @hp: HVC console pointer
709 * @ws: Terminal window size structure
711 * Stores the specified window size information in the hvc structure of @hp.
712 * The function schedule the tty resize update.
714 * Locking: Locking free; the function MUST be called holding hp->lock
716 void __hvc_resize(struct hvc_struct *hp, struct winsize ws)
719 schedule_work(&hp->tty_resize);
721 EXPORT_SYMBOL_GPL(__hvc_resize);
724 * This kthread is either polling or interrupt driven. This is determined by
725 * calling hvc_poll() who determines whether a console adapter support
728 static int khvcd(void *unused)
731 struct hvc_struct *hp;
739 if (!cpus_are_in_xmon()) {
740 spin_lock(&hvc_structs_lock);
741 list_for_each_entry(hp, &hvc_structs, next) {
742 poll_mask |= hvc_poll(hp);
744 spin_unlock(&hvc_structs_lock);
746 poll_mask |= HVC_POLL_READ;
749 set_current_state(TASK_INTERRUPTIBLE);
754 if (timeout < MAX_TIMEOUT)
755 timeout += (timeout >> 6) + 1;
757 msleep_interruptible(timeout);
760 __set_current_state(TASK_RUNNING);
761 } while (!kthread_should_stop());
766 static int hvc_tiocmget(struct tty_struct *tty)
768 struct hvc_struct *hp = tty->driver_data;
770 if (!hp || !hp->ops->tiocmget)
772 return hp->ops->tiocmget(hp);
775 static int hvc_tiocmset(struct tty_struct *tty,
776 unsigned int set, unsigned int clear)
778 struct hvc_struct *hp = tty->driver_data;
780 if (!hp || !hp->ops->tiocmset)
782 return hp->ops->tiocmset(hp, set, clear);
785 #ifdef CONFIG_CONSOLE_POLL
786 int hvc_poll_init(struct tty_driver *driver, int line, char *options)
791 static int hvc_poll_get_char(struct tty_driver *driver, int line)
793 struct tty_struct *tty = driver->ttys[0];
794 struct hvc_struct *hp = tty->driver_data;
798 n = hp->ops->get_chars(hp->vtermno, &ch, 1);
806 static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)
808 struct tty_struct *tty = driver->ttys[0];
809 struct hvc_struct *hp = tty->driver_data;
813 n = hp->ops->put_chars(hp->vtermno, &ch, 1);
818 static const struct tty_operations hvc_ops = {
819 .install = hvc_install,
822 .cleanup = hvc_cleanup,
824 .hangup = hvc_hangup,
825 .unthrottle = hvc_unthrottle,
826 .write_room = hvc_write_room,
827 .chars_in_buffer = hvc_chars_in_buffer,
828 .tiocmget = hvc_tiocmget,
829 .tiocmset = hvc_tiocmset,
830 #ifdef CONFIG_CONSOLE_POLL
831 .poll_init = hvc_poll_init,
832 .poll_get_char = hvc_poll_get_char,
833 .poll_put_char = hvc_poll_put_char,
837 static const struct tty_port_operations hvc_port_ops = {
838 .destruct = hvc_port_destruct,
841 struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
842 const struct hv_ops *ops,
845 struct hvc_struct *hp;
848 /* We wait until a driver actually comes along */
849 if (atomic_inc_not_zero(&hvc_needs_init)) {
850 int err = hvc_init();
855 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
858 return ERR_PTR(-ENOMEM);
860 hp->vtermno = vtermno;
863 hp->outbuf_size = outbuf_size;
864 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
866 tty_port_init(&hp->port);
867 hp->port.ops = &hvc_port_ops;
869 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
870 spin_lock_init(&hp->lock);
871 spin_lock(&hvc_structs_lock);
875 * see if this vterm id matches one registered for console.
877 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
878 if (vtermnos[i] == hp->vtermno &&
879 cons_ops[i] == hp->ops)
882 /* no matching slot, just use a counter */
883 if (i >= MAX_NR_HVC_CONSOLES)
888 vtermnos[i] = vtermno;
890 list_add_tail(&(hp->next), &hvc_structs);
891 spin_unlock(&hvc_structs_lock);
893 /* check if we need to re-register the kernel console */
894 hvc_check_console(i);
898 EXPORT_SYMBOL_GPL(hvc_alloc);
900 int hvc_remove(struct hvc_struct *hp)
903 struct tty_struct *tty;
905 tty = tty_port_tty_get(&hp->port);
907 spin_lock_irqsave(&hp->lock, flags);
908 if (hp->index < MAX_NR_HVC_CONSOLES) {
910 vtermnos[hp->index] = -1;
911 cons_ops[hp->index] = NULL;
915 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
917 spin_unlock_irqrestore(&hp->lock, flags);
920 * We 'put' the instance that was grabbed when the kref instance
921 * was initialized using kref_init(). Let the last holder of this
922 * kref cause it to be removed, which will probably be the tty_vhangup
925 tty_port_put(&hp->port);
928 * This function call will auto chain call hvc_hangup.
936 EXPORT_SYMBOL_GPL(hvc_remove);
938 /* Driver initialization: called as soon as someone uses hvc_alloc(). */
939 static int hvc_init(void)
941 struct tty_driver *drv;
944 /* We need more than hvc_count adapters due to hotplug additions. */
945 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
951 drv->driver_name = "hvc";
953 drv->major = HVC_MAJOR;
954 drv->minor_start = HVC_MINOR;
955 drv->type = TTY_DRIVER_TYPE_SYSTEM;
956 drv->init_termios = tty_std_termios;
957 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
958 tty_set_operations(drv, &hvc_ops);
960 /* Always start the kthread because there can be hotplug vty adapters
962 hvc_task = kthread_run(khvcd, NULL, "khvcd");
963 if (IS_ERR(hvc_task)) {
964 printk(KERN_ERR "Couldn't create kthread for console.\n");
965 err = PTR_ERR(hvc_task);
969 err = tty_register_driver(drv);
971 printk(KERN_ERR "Couldn't register hvc console driver\n");
976 * Make sure tty is fully registered before allowing it to be
977 * found by hvc_console_device.
984 kthread_stop(hvc_task);
992 /* This isn't particularly necessary due to this being a console driver
993 * but it is nice to be thorough.
995 static void __exit hvc_exit(void)
998 kthread_stop(hvc_task);
1000 tty_unregister_driver(hvc_driver);
1001 /* return tty_struct instances allocated in hvc_init(). */
1002 put_tty_driver(hvc_driver);
1003 unregister_console(&hvc_console);
1006 module_exit(hvc_exit);