]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/char/hvc_console.c
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>
42 #include <asm/uaccess.h>
44 #include "hvc_console.h"
50 * Wait this long per iteration while trying to push buffered data to the
51 * hypervisor before allowing the tty to complete a close operation.
53 #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
56 * These sizes are most efficient for vio, because they are the
57 * native transfer size. We could make them selectable in the
58 * future to better deal with backends that want other buffer sizes.
63 #define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
65 static struct tty_driver
*hvc_driver
;
66 static struct task_struct
*hvc_task
;
68 /* Picks up late kicks after list walk but before schedule() */
69 static int hvc_kicked
;
71 static int hvc_init(void);
73 #ifdef CONFIG_MAGIC_SYSRQ
74 static int sysrq_pressed
;
77 /* dynamic list of hvc_struct instances */
78 static LIST_HEAD(hvc_structs
);
81 * Protect the list of hvc_struct instances from inserts and removals during
84 static DEFINE_SPINLOCK(hvc_structs_lock
);
87 * This value is used to assign a tty->index value to a hvc_struct based
88 * upon order of exposure via hvc_probe(), when we can not match it to
89 * a console candidate registered with hvc_instantiate().
91 static int last_hvc
= -1;
94 * Do not call this function with either the hvc_structs_lock or the hvc_struct
95 * lock held. If successful, this function increments the kref reference
96 * count against the target hvc_struct so it should be released when finished.
98 static struct hvc_struct
*hvc_get_by_index(int index
)
100 struct hvc_struct
*hp
;
103 spin_lock(&hvc_structs_lock
);
105 list_for_each_entry(hp
, &hvc_structs
, next
) {
106 spin_lock_irqsave(&hp
->lock
, flags
);
107 if (hp
->index
== index
) {
109 spin_unlock_irqrestore(&hp
->lock
, flags
);
110 spin_unlock(&hvc_structs_lock
);
113 spin_unlock_irqrestore(&hp
->lock
, flags
);
117 spin_unlock(&hvc_structs_lock
);
123 * Initial console vtermnos for console API usage prior to full console
124 * initialization. Any vty adapter outside this range will not have usable
125 * console interfaces but can still be used as a tty device. This has to be
126 * static because kmalloc will not work during early console init.
128 static struct hv_ops
*cons_ops
[MAX_NR_HVC_CONSOLES
];
129 static uint32_t vtermnos
[MAX_NR_HVC_CONSOLES
] =
130 {[0 ... MAX_NR_HVC_CONSOLES
- 1] = -1};
133 * Console APIs, NOT TTY. These APIs are available immediately when
134 * hvc_console_setup() finds adapters.
137 static void hvc_console_print(struct console
*co
, const char *b
,
140 char c
[N_OUTBUF
] __ALIGNED__
;
141 unsigned i
= 0, n
= 0;
142 int r
, donecr
= 0, index
= co
->index
;
144 /* Console access attempt outside of acceptable console range. */
145 if (index
>= MAX_NR_HVC_CONSOLES
)
148 /* This console adapter was removed so it is not usable. */
149 if (vtermnos
[index
] < 0)
152 while (count
> 0 || i
> 0) {
153 if (count
> 0 && i
< sizeof(c
)) {
154 if (b
[n
] == '\n' && !donecr
) {
163 r
= cons_ops
[index
]->put_chars(vtermnos
[index
], c
, i
);
165 /* throw away chars on error */
176 static struct tty_driver
*hvc_console_device(struct console
*c
, int *index
)
178 if (vtermnos
[c
->index
] == -1)
185 static int __init
hvc_console_setup(struct console
*co
, char *options
)
187 if (co
->index
< 0 || co
->index
>= MAX_NR_HVC_CONSOLES
)
190 if (vtermnos
[co
->index
] == -1)
196 static struct console hvc_con_driver
= {
198 .write
= hvc_console_print
,
199 .device
= hvc_console_device
,
200 .setup
= hvc_console_setup
,
201 .flags
= CON_PRINTBUFFER
,
206 * Early console initialization. Precedes driver initialization.
208 * (1) we are first, and the user specified another driver
209 * -- index will remain -1
210 * (2) we are first and the user specified no driver
211 * -- index will be set to 0, then we will fail setup.
212 * (3) we are first and the user specified our driver
213 * -- index will be set to user specified driver, and we will fail
214 * (4) we are after driver, and this initcall will register us
215 * -- if the user didn't specify a driver then the console will match
217 * Note that for cases 2 and 3, we will match later when the io driver
218 * calls hvc_instantiate() and call register again.
220 static int __init
hvc_console_init(void)
222 register_console(&hvc_con_driver
);
225 console_initcall(hvc_console_init
);
227 /* callback when the kboject ref count reaches zero. */
228 static void destroy_hvc_struct(struct kref
*kref
)
230 struct hvc_struct
*hp
= container_of(kref
, struct hvc_struct
, kref
);
233 spin_lock(&hvc_structs_lock
);
235 spin_lock_irqsave(&hp
->lock
, flags
);
236 list_del(&(hp
->next
));
237 spin_unlock_irqrestore(&hp
->lock
, flags
);
239 spin_unlock(&hvc_structs_lock
);
245 * hvc_instantiate() is an early console discovery method which locates
246 * consoles * prior to the vio subsystem discovering them. Hotplugged
247 * vty adapters do NOT get an hvc_instantiate() callback since they
248 * appear after early console init.
250 int hvc_instantiate(uint32_t vtermno
, int index
, struct hv_ops
*ops
)
252 struct hvc_struct
*hp
;
254 if (index
< 0 || index
>= MAX_NR_HVC_CONSOLES
)
257 if (vtermnos
[index
] != -1)
260 /* make sure no no tty has been registered in this index */
261 hp
= hvc_get_by_index(index
);
263 kref_put(&hp
->kref
, destroy_hvc_struct
);
267 vtermnos
[index
] = vtermno
;
268 cons_ops
[index
] = ops
;
270 /* reserve all indices up to and including this index */
271 if (last_hvc
< index
)
274 /* if this index is what the user requested, then register
275 * now (setup won't fail at this point). It's ok to just
276 * call register again if previously .setup failed.
278 if (index
== hvc_con_driver
.index
)
279 register_console(&hvc_con_driver
);
283 EXPORT_SYMBOL_GPL(hvc_instantiate
);
285 /* Wake the sleeping khvcd */
289 wake_up_process(hvc_task
);
291 EXPORT_SYMBOL_GPL(hvc_kick
);
293 static void hvc_unthrottle(struct tty_struct
*tty
)
299 * The TTY interface won't be used until after the vio layer has exposed the vty
300 * adapter to the kernel.
302 static int hvc_open(struct tty_struct
*tty
, struct file
* filp
)
304 struct hvc_struct
*hp
;
308 /* Auto increments kref reference if found. */
309 if (!(hp
= hvc_get_by_index(tty
->index
)))
312 spin_lock_irqsave(&hp
->lock
, flags
);
313 /* Check and then increment for fast path open. */
314 if (hp
->count
++ > 0) {
315 spin_unlock_irqrestore(&hp
->lock
, flags
);
318 } /* else count == 0 */
320 tty
->driver_data
= hp
;
324 spin_unlock_irqrestore(&hp
->lock
, flags
);
326 if (hp
->ops
->notifier_add
)
327 rc
= hp
->ops
->notifier_add(hp
, hp
->data
);
330 * If the notifier fails we return an error. The tty layer
331 * will call hvc_close() after a failed open but we don't want to clean
332 * up there so we'll clean up here and clear out the previously set
333 * tty fields and return the kref reference.
336 spin_lock_irqsave(&hp
->lock
, flags
);
338 spin_unlock_irqrestore(&hp
->lock
, flags
);
339 tty
->driver_data
= NULL
;
340 kref_put(&hp
->kref
, destroy_hvc_struct
);
341 printk(KERN_ERR
"hvc_open: request_irq failed with rc %d.\n", rc
);
343 /* Force wakeup of the polling thread */
349 static void hvc_close(struct tty_struct
*tty
, struct file
* filp
)
351 struct hvc_struct
*hp
;
354 if (tty_hung_up_p(filp
))
358 * No driver_data means that this close was issued after a failed
359 * hvc_open by the tty layer's release_dev() function and we can just
360 * exit cleanly because the kref reference wasn't made.
362 if (!tty
->driver_data
)
365 hp
= tty
->driver_data
;
366 spin_lock_irqsave(&hp
->lock
, flags
);
368 if (--hp
->count
== 0) {
369 /* We are done with the tty pointer now. */
371 spin_unlock_irqrestore(&hp
->lock
, flags
);
373 if (hp
->ops
->notifier_del
)
374 hp
->ops
->notifier_del(hp
, hp
->data
);
376 /* cancel pending tty resize work */
377 cancel_work_sync(&hp
->tty_resize
);
380 * Chain calls chars_in_buffer() and returns immediately if
381 * there is no buffered data otherwise sleeps on a wait queue
382 * waking periodically to check chars_in_buffer().
384 tty_wait_until_sent(tty
, HVC_CLOSE_WAIT
);
387 printk(KERN_ERR
"hvc_close %X: oops, count is %d\n",
388 hp
->vtermno
, hp
->count
);
389 spin_unlock_irqrestore(&hp
->lock
, flags
);
392 kref_put(&hp
->kref
, destroy_hvc_struct
);
395 static void hvc_hangup(struct tty_struct
*tty
)
397 struct hvc_struct
*hp
= tty
->driver_data
;
404 /* cancel pending tty resize work */
405 cancel_work_sync(&hp
->tty_resize
);
407 spin_lock_irqsave(&hp
->lock
, flags
);
410 * The N_TTY line discipline has problems such that in a close vs
411 * open->hangup case this can be called after the final close so prevent
412 * that from happening for now.
414 if (hp
->count
<= 0) {
415 spin_unlock_irqrestore(&hp
->lock
, flags
);
419 temp_open_count
= hp
->count
;
424 spin_unlock_irqrestore(&hp
->lock
, flags
);
426 if (hp
->ops
->notifier_hangup
)
427 hp
->ops
->notifier_hangup(hp
, hp
->data
);
429 while(temp_open_count
) {
431 kref_put(&hp
->kref
, destroy_hvc_struct
);
436 * Push buffered characters whether they were just recently buffered or waiting
437 * on a blocked hypervisor. Call this function with hp->lock held.
439 static int hvc_push(struct hvc_struct
*hp
)
443 n
= hp
->ops
->put_chars(hp
->vtermno
, hp
->outbuf
, hp
->n_outbuf
);
449 /* throw away output on error; this happens when
450 there is no session connected to the vterm. */
454 if (hp
->n_outbuf
> 0)
455 memmove(hp
->outbuf
, hp
->outbuf
+ n
, hp
->n_outbuf
);
462 static int hvc_write(struct tty_struct
*tty
, const unsigned char *buf
, int count
)
464 struct hvc_struct
*hp
= tty
->driver_data
;
466 int rsize
, written
= 0;
468 /* This write was probably executed during a tty close. */
475 spin_lock_irqsave(&hp
->lock
, flags
);
477 /* Push pending writes */
478 if (hp
->n_outbuf
> 0)
481 while (count
> 0 && (rsize
= hp
->outbuf_size
- hp
->n_outbuf
) > 0) {
484 memcpy(hp
->outbuf
+ hp
->n_outbuf
, buf
, rsize
);
487 hp
->n_outbuf
+= rsize
;
491 spin_unlock_irqrestore(&hp
->lock
, flags
);
494 * Racy, but harmless, kick thread if there is still pending data.
503 * hvc_set_winsz() - Resize the hvc tty terminal window.
504 * @work: work structure.
506 * The routine shall not be called within an atomic context because it
511 static void hvc_set_winsz(struct work_struct
*work
)
513 struct hvc_struct
*hp
;
514 unsigned long hvc_flags
;
515 struct tty_struct
*tty
;
518 hp
= container_of(work
, struct hvc_struct
, tty_resize
);
520 spin_lock_irqsave(&hp
->lock
, hvc_flags
);
522 spin_unlock_irqrestore(&hp
->lock
, hvc_flags
);
526 tty
= tty_kref_get(hp
->tty
);
527 spin_unlock_irqrestore(&hp
->lock
, hvc_flags
);
529 tty_do_resize(tty
, &ws
);
534 * This is actually a contract between the driver and the tty layer outlining
535 * how much write room the driver can guarantee will be sent OR BUFFERED. This
536 * driver MUST honor the return value.
538 static int hvc_write_room(struct tty_struct
*tty
)
540 struct hvc_struct
*hp
= tty
->driver_data
;
545 return hp
->outbuf_size
- hp
->n_outbuf
;
548 static int hvc_chars_in_buffer(struct tty_struct
*tty
)
550 struct hvc_struct
*hp
= tty
->driver_data
;
558 * timeout will vary between the MIN and MAX values defined here. By default
559 * and during console activity we will use a default MIN_TIMEOUT of 10. When
560 * the console is idle, we increase the timeout value on each pass through
561 * msleep until we reach the max. This may be noticeable as a brief (average
562 * one second) delay on the console before the console responds to input when
563 * there has been no input for some time.
565 #define MIN_TIMEOUT (10)
566 #define MAX_TIMEOUT (2000)
567 static u32 timeout
= MIN_TIMEOUT
;
569 #define HVC_POLL_READ 0x00000001
570 #define HVC_POLL_WRITE 0x00000002
572 int hvc_poll(struct hvc_struct
*hp
)
574 struct tty_struct
*tty
;
575 int i
, n
, poll_mask
= 0;
576 char buf
[N_INBUF
] __ALIGNED__
;
579 int written_total
= 0;
581 spin_lock_irqsave(&hp
->lock
, flags
);
583 /* Push pending writes */
584 if (hp
->n_outbuf
> 0)
585 written_total
= hvc_push(hp
);
587 /* Reschedule us if still some write pending */
588 if (hp
->n_outbuf
> 0) {
589 poll_mask
|= HVC_POLL_WRITE
;
590 /* If hvc_push() was not able to write, sleep a few msecs */
591 timeout
= (written_total
) ? 0 : MIN_TIMEOUT
;
594 /* No tty attached, just skip */
599 /* Now check if we can get data (are we throttled ?) */
600 if (test_bit(TTY_THROTTLED
, &tty
->flags
))
603 /* If we aren't notifier driven and aren't throttled, we always
604 * request a reschedule
606 if (!hp
->irq_requested
)
607 poll_mask
|= HVC_POLL_READ
;
609 /* Read data if any */
611 int count
= tty_buffer_request_room(tty
, N_INBUF
);
613 /* If flip is full, just reschedule a later read */
615 poll_mask
|= HVC_POLL_READ
;
619 n
= hp
->ops
->get_chars(hp
->vtermno
, buf
, count
);
621 /* Hangup the tty when disconnected from host */
623 spin_unlock_irqrestore(&hp
->lock
, flags
);
625 spin_lock_irqsave(&hp
->lock
, flags
);
626 } else if ( n
== -EAGAIN
) {
628 * Some back-ends can only ensure a certain min
629 * num of bytes read, which may be > 'count'.
630 * Let the tty clear the flip buff to make room.
632 poll_mask
|= HVC_POLL_READ
;
636 for (i
= 0; i
< n
; ++i
) {
637 #ifdef CONFIG_MAGIC_SYSRQ
638 if (hp
->index
== hvc_con_driver
.index
) {
639 /* Handle the SysRq Hack */
640 /* XXX should support a sequence */
641 if (buf
[i
] == '\x0f') { /* ^O */
642 /* if ^O is pressed again, reset
643 * sysrq_pressed and flip ^O char */
644 sysrq_pressed
= !sysrq_pressed
;
647 } else if (sysrq_pressed
) {
648 handle_sysrq(buf
[i
], tty
);
653 #endif /* CONFIG_MAGIC_SYSRQ */
654 tty_insert_flip_char(tty
, buf
[i
], 0);
660 /* Wakeup write queue if necessary */
666 spin_unlock_irqrestore(&hp
->lock
, flags
);
669 /* Activity is occurring, so reset the polling backoff value to
670 a minimum for performance. */
671 timeout
= MIN_TIMEOUT
;
673 tty_flip_buffer_push(tty
);
678 EXPORT_SYMBOL_GPL(hvc_poll
);
681 * __hvc_resize() - Update terminal window size information.
682 * @hp: HVC console pointer
683 * @ws: Terminal window size structure
685 * Stores the specified window size information in the hvc structure of @hp.
686 * The function schedule the tty resize update.
688 * Locking: Locking free; the function MUST be called holding hp->lock
690 void __hvc_resize(struct hvc_struct
*hp
, struct winsize ws
)
693 schedule_work(&hp
->tty_resize
);
695 EXPORT_SYMBOL_GPL(__hvc_resize
);
698 * This kthread is either polling or interrupt driven. This is determined by
699 * calling hvc_poll() who determines whether a console adapter support
702 static int khvcd(void *unused
)
705 struct hvc_struct
*hp
;
708 __set_current_state(TASK_RUNNING
);
714 if (!cpus_are_in_xmon()) {
715 spin_lock(&hvc_structs_lock
);
716 list_for_each_entry(hp
, &hvc_structs
, next
) {
717 poll_mask
|= hvc_poll(hp
);
719 spin_unlock(&hvc_structs_lock
);
721 poll_mask
|= HVC_POLL_READ
;
724 set_current_state(TASK_INTERRUPTIBLE
);
729 if (timeout
< MAX_TIMEOUT
)
730 timeout
+= (timeout
>> 6) + 1;
732 msleep_interruptible(timeout
);
735 __set_current_state(TASK_RUNNING
);
736 } while (!kthread_should_stop());
741 static const struct tty_operations hvc_ops
= {
745 .hangup
= hvc_hangup
,
746 .unthrottle
= hvc_unthrottle
,
747 .write_room
= hvc_write_room
,
748 .chars_in_buffer
= hvc_chars_in_buffer
,
751 struct hvc_struct __devinit
*hvc_alloc(uint32_t vtermno
, int data
,
752 struct hv_ops
*ops
, int outbuf_size
)
754 struct hvc_struct
*hp
;
757 /* We wait until a driver actually comes along */
759 int err
= hvc_init();
764 hp
= kzalloc(ALIGN(sizeof(*hp
), sizeof(long)) + outbuf_size
,
767 return ERR_PTR(-ENOMEM
);
769 hp
->vtermno
= vtermno
;
772 hp
->outbuf_size
= outbuf_size
;
773 hp
->outbuf
= &((char *)hp
)[ALIGN(sizeof(*hp
), sizeof(long))];
775 kref_init(&hp
->kref
);
777 INIT_WORK(&hp
->tty_resize
, hvc_set_winsz
);
778 spin_lock_init(&hp
->lock
);
779 spin_lock(&hvc_structs_lock
);
783 * see if this vterm id matches one registered for console.
785 for (i
=0; i
< MAX_NR_HVC_CONSOLES
; i
++)
786 if (vtermnos
[i
] == hp
->vtermno
&&
787 cons_ops
[i
] == hp
->ops
)
790 /* no matching slot, just use a counter */
791 if (i
>= MAX_NR_HVC_CONSOLES
)
796 list_add_tail(&(hp
->next
), &hvc_structs
);
797 spin_unlock(&hvc_structs_lock
);
801 EXPORT_SYMBOL_GPL(hvc_alloc
);
803 int hvc_remove(struct hvc_struct
*hp
)
806 struct tty_struct
*tty
;
808 spin_lock_irqsave(&hp
->lock
, flags
);
811 if (hp
->index
< MAX_NR_HVC_CONSOLES
)
812 vtermnos
[hp
->index
] = -1;
814 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
816 spin_unlock_irqrestore(&hp
->lock
, flags
);
819 * We 'put' the instance that was grabbed when the kref instance
820 * was initialized using kref_init(). Let the last holder of this
821 * kref cause it to be removed, which will probably be the tty_hangup
824 kref_put(&hp
->kref
, destroy_hvc_struct
);
827 * This function call will auto chain call hvc_hangup. The tty should
828 * always be valid at this time unless a simultaneous tty close already
829 * cleaned up the hvc_struct.
835 EXPORT_SYMBOL_GPL(hvc_remove
);
837 /* Driver initialization: called as soon as someone uses hvc_alloc(). */
838 static int hvc_init(void)
840 struct tty_driver
*drv
;
843 /* We need more than hvc_count adapters due to hotplug additions. */
844 drv
= alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS
);
850 drv
->owner
= THIS_MODULE
;
851 drv
->driver_name
= "hvc";
853 drv
->major
= HVC_MAJOR
;
854 drv
->minor_start
= HVC_MINOR
;
855 drv
->type
= TTY_DRIVER_TYPE_SYSTEM
;
856 drv
->init_termios
= tty_std_termios
;
857 drv
->flags
= TTY_DRIVER_REAL_RAW
| TTY_DRIVER_RESET_TERMIOS
;
858 tty_set_operations(drv
, &hvc_ops
);
860 /* Always start the kthread because there can be hotplug vty adapters
862 hvc_task
= kthread_run(khvcd
, NULL
, "khvcd");
863 if (IS_ERR(hvc_task
)) {
864 printk(KERN_ERR
"Couldn't create kthread for console.\n");
865 err
= PTR_ERR(hvc_task
);
869 err
= tty_register_driver(drv
);
871 printk(KERN_ERR
"Couldn't register hvc console driver\n");
876 * Make sure tty is fully registered before allowing it to be
877 * found by hvc_console_device.
884 kthread_stop(hvc_task
);
892 /* This isn't particularly necessary due to this being a console driver
893 * but it is nice to be thorough.
895 static void __exit
hvc_exit(void)
898 kthread_stop(hvc_task
);
900 tty_unregister_driver(hvc_driver
);
901 /* return tty_struct instances allocated in hvc_init(). */
902 put_tty_driver(hvc_driver
);
903 unregister_console(&hvc_con_driver
);
906 module_exit(hvc_exit
);