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/config.h>
26 #include <linux/console.h>
27 #include <linux/cpumask.h>
28 #include <linux/init.h>
29 #include <linux/kbd_kern.h>
30 #include <linux/kernel.h>
31 #include <linux/kobject.h>
32 #include <linux/kthread.h>
33 #include <linux/list.h>
34 #include <linux/module.h>
35 #include <linux/major.h>
36 #include <linux/sysrq.h>
37 #include <linux/tty.h>
38 #include <linux/tty_flip.h>
39 #include <linux/sched.h>
40 #include <linux/spinlock.h>
41 #include <linux/delay.h>
42 #include <asm/uaccess.h>
43 #include <asm/hvconsole.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 * The Linux TTY code does not support dynamic addition of tty derived devices
59 * so we need to know how many tty devices we might need when space is allocated
60 * for the tty device. Since this driver supports hotplug of vty adapters we
61 * need to make sure we have enough allocated.
63 #define HVC_ALLOC_TTY_ADAPTERS 8
68 #define __ALIGNED__ __attribute__((__aligned__(8)))
70 static struct tty_driver
*hvc_driver
;
71 static struct task_struct
*hvc_task
;
73 /* Picks up late kicks after list walk but before schedule() */
74 static int hvc_kicked
;
76 #ifdef CONFIG_MAGIC_SYSRQ
77 static int sysrq_pressed
;
83 struct tty_struct
*tty
;
86 char outbuf
[N_OUTBUF
] __ALIGNED__
;
91 struct list_head next
;
92 struct kobject kobj
; /* ref count & hvc_struct lifetime */
96 /* dynamic list of hvc_struct instances */
97 static struct list_head hvc_structs
= LIST_HEAD_INIT(hvc_structs
);
100 * Protect the list of hvc_struct instances from inserts and removals during
103 static DEFINE_SPINLOCK(hvc_structs_lock
);
106 * This value is used to assign a tty->index value to a hvc_struct based
107 * upon order of exposure via hvc_probe(), when we can not match it to
108 * a console canidate registered with hvc_instantiate().
110 static int last_hvc
= -1;
113 * Do not call this function with either the hvc_strucst_lock or the hvc_struct
114 * lock held. If successful, this function increments the kobject reference
115 * count against the target hvc_struct so it should be released when finished.
117 struct hvc_struct
*hvc_get_by_index(int index
)
119 struct hvc_struct
*hp
;
122 spin_lock(&hvc_structs_lock
);
124 list_for_each_entry(hp
, &hvc_structs
, next
) {
125 spin_lock_irqsave(&hp
->lock
, flags
);
126 if (hp
->index
== index
) {
127 kobject_get(&hp
->kobj
);
128 spin_unlock_irqrestore(&hp
->lock
, flags
);
129 spin_unlock(&hvc_structs_lock
);
132 spin_unlock_irqrestore(&hp
->lock
, flags
);
136 spin_unlock(&hvc_structs_lock
);
142 * Initial console vtermnos for console API usage prior to full console
143 * initialization. Any vty adapter outside this range will not have usable
144 * console interfaces but can still be used as a tty device. This has to be
145 * static because kmalloc will not work during early console init.
147 static uint32_t vtermnos
[MAX_NR_HVC_CONSOLES
] =
148 {[0 ... MAX_NR_HVC_CONSOLES
- 1] = -1};
151 * Console APIs, NOT TTY. These APIs are available immediately when
152 * hvc_console_setup() finds adapters.
155 void hvc_console_print(struct console
*co
, const char *b
, unsigned count
)
157 char c
[16] __ALIGNED__
;
158 unsigned i
= 0, n
= 0;
161 /* Console access attempt outside of acceptable console range. */
162 if (co
->index
>= MAX_NR_HVC_CONSOLES
)
165 /* This console adapter was removed so it is not useable. */
166 if (vtermnos
[co
->index
] < 0)
169 while (count
> 0 || i
> 0) {
170 if (count
> 0 && i
< sizeof(c
)) {
171 if (b
[n
] == '\n' && !donecr
) {
180 r
= hvc_put_chars(vtermnos
[co
->index
], c
, i
);
182 /* throw away chars on error */
193 static struct tty_driver
*hvc_console_device(struct console
*c
, int *index
)
199 static int __init
hvc_console_setup(struct console
*co
, char *options
)
204 struct console hvc_con_driver
= {
206 .write
= hvc_console_print
,
207 .device
= hvc_console_device
,
208 .setup
= hvc_console_setup
,
209 .flags
= CON_PRINTBUFFER
,
213 /* Early console initialization. Preceeds driver initialization. */
214 static int __init
hvc_console_init(void)
217 register_console(&hvc_con_driver
);
220 console_initcall(hvc_console_init
);
223 * hvc_instantiate() is an early console discovery method which locates
224 * consoles * prior to the vio subsystem discovering them. Hotplugged
225 * vty adapters do NOT get an hvc_instantiate() callback since they
226 * appear after early console init.
228 int hvc_instantiate(uint32_t vtermno
, int index
)
230 if (index
< 0 || index
>= MAX_NR_HVC_CONSOLES
)
233 if (vtermnos
[index
] != -1)
236 vtermnos
[index
] = vtermno
;
238 /* reserve all indices upto and including this index */
239 if (last_hvc
< index
)
245 /* Wake the sleeping khvcd */
246 static void hvc_kick(void)
249 wake_up_process(hvc_task
);
252 static int hvc_poll(struct hvc_struct
*hp
);
255 * NOTE: This API isn't used if the console adapter doesn't support interrupts.
256 * In this case the console is poll driven.
258 static irqreturn_t
hvc_handle_interrupt(int irq
, void *dev_instance
, struct pt_regs
*regs
)
260 /* if hvc_poll request a repoll, then kick the hvcd thread */
261 if (hvc_poll(dev_instance
))
266 static void hvc_unthrottle(struct tty_struct
*tty
)
272 * The TTY interface won't be used until after the vio layer has exposed the vty
273 * adapter to the kernel.
275 static int hvc_open(struct tty_struct
*tty
, struct file
* filp
)
277 struct hvc_struct
*hp
;
281 struct kobject
*kobjp
;
283 /* Auto increments kobject reference if found. */
284 if (!(hp
= hvc_get_by_index(tty
->index
))) {
285 printk(KERN_WARNING
"hvc_console: tty open failed, no vty associated with tty.\n");
289 spin_lock_irqsave(&hp
->lock
, flags
);
290 /* Check and then increment for fast path open. */
291 if (hp
->count
++ > 0) {
292 spin_unlock_irqrestore(&hp
->lock
, flags
);
295 } /* else count == 0 */
297 tty
->driver_data
= hp
;
299 /* Save for request_irq outside of spin_lock. */
302 hp
->irq_requested
= 1;
306 spin_unlock_irqrestore(&hp
->lock
, flags
);
307 /* check error, fallback to non-irq */
309 rc
= request_irq(irq
, hvc_handle_interrupt
, SA_INTERRUPT
, "hvc_console", hp
);
312 * If the request_irq() fails and we return an error. The tty layer
313 * will call hvc_close() after a failed open but we don't want to clean
314 * up there so we'll clean up here and clear out the previously set
315 * tty fields and return the kobject reference.
318 spin_lock_irqsave(&hp
->lock
, flags
);
320 hp
->irq_requested
= 0;
321 spin_unlock_irqrestore(&hp
->lock
, flags
);
322 tty
->driver_data
= NULL
;
324 printk(KERN_ERR
"hvc_open: request_irq failed with rc %d.\n", rc
);
326 /* Force wakeup of the polling thread */
332 static void hvc_close(struct tty_struct
*tty
, struct file
* filp
)
334 struct hvc_struct
*hp
;
335 struct kobject
*kobjp
;
339 if (tty_hung_up_p(filp
))
343 * No driver_data means that this close was issued after a failed
344 * hvc_open by the tty layer's release_dev() function and we can just
345 * exit cleanly because the kobject reference wasn't made.
347 if (!tty
->driver_data
)
350 hp
= tty
->driver_data
;
351 spin_lock_irqsave(&hp
->lock
, flags
);
354 if (--hp
->count
== 0) {
355 if (hp
->irq_requested
)
357 hp
->irq_requested
= 0;
359 /* We are done with the tty pointer now. */
361 spin_unlock_irqrestore(&hp
->lock
, flags
);
364 * Chain calls chars_in_buffer() and returns immediately if
365 * there is no buffered data otherwise sleeps on a wait queue
366 * waking periodically to check chars_in_buffer().
368 tty_wait_until_sent(tty
, HVC_CLOSE_WAIT
);
375 printk(KERN_ERR
"hvc_close %X: oops, count is %d\n",
376 hp
->vtermno
, hp
->count
);
377 spin_unlock_irqrestore(&hp
->lock
, flags
);
383 static void hvc_hangup(struct tty_struct
*tty
)
385 struct hvc_struct
*hp
= tty
->driver_data
;
389 struct kobject
*kobjp
;
394 spin_lock_irqsave(&hp
->lock
, flags
);
397 * The N_TTY line discipline has problems such that in a close vs
398 * open->hangup case this can be called after the final close so prevent
399 * that from happening for now.
401 if (hp
->count
<= 0) {
402 spin_unlock_irqrestore(&hp
->lock
, flags
);
407 temp_open_count
= hp
->count
;
411 if (hp
->irq_requested
)
412 /* Saved for use outside of spin_lock. */
414 hp
->irq_requested
= 0;
415 spin_unlock_irqrestore(&hp
->lock
, flags
);
418 while(temp_open_count
) {
425 * Push buffered characters whether they were just recently buffered or waiting
426 * on a blocked hypervisor. Call this function with hp->lock held.
428 static void hvc_push(struct hvc_struct
*hp
)
432 n
= hvc_put_chars(hp
->vtermno
, hp
->outbuf
, hp
->n_outbuf
);
436 /* throw away output on error; this happens when
437 there is no session connected to the vterm. */
441 if (hp
->n_outbuf
> 0)
442 memmove(hp
->outbuf
, hp
->outbuf
+ n
, hp
->n_outbuf
);
447 static inline int __hvc_write_kernel(struct hvc_struct
*hp
,
448 const unsigned char *buf
, int count
)
451 int rsize
, written
= 0;
453 spin_lock_irqsave(&hp
->lock
, flags
);
455 /* Push pending writes */
456 if (hp
->n_outbuf
> 0)
459 while (count
> 0 && (rsize
= N_OUTBUF
- hp
->n_outbuf
) > 0) {
462 memcpy(hp
->outbuf
+ hp
->n_outbuf
, buf
, rsize
);
465 hp
->n_outbuf
+= rsize
;
469 spin_unlock_irqrestore(&hp
->lock
, flags
);
473 static int hvc_write(struct tty_struct
*tty
, const unsigned char *buf
, int count
)
475 struct hvc_struct
*hp
= tty
->driver_data
;
478 /* This write was probably executed during a tty close. */
485 written
= __hvc_write_kernel(hp
, buf
, count
);
488 * Racy, but harmless, kick thread if there is still pending data.
489 * There really is nothing wrong with kicking the thread, even if there
490 * is no buffered data.
499 * This is actually a contract between the driver and the tty layer outlining
500 * how much write room the driver can guarentee will be sent OR BUFFERED. This
501 * driver MUST honor the return value.
503 static int hvc_write_room(struct tty_struct
*tty
)
505 struct hvc_struct
*hp
= tty
->driver_data
;
510 return N_OUTBUF
- hp
->n_outbuf
;
513 static int hvc_chars_in_buffer(struct tty_struct
*tty
)
515 struct hvc_struct
*hp
= tty
->driver_data
;
522 #define HVC_POLL_READ 0x00000001
523 #define HVC_POLL_WRITE 0x00000002
524 #define HVC_POLL_QUICK 0x00000004
526 static int hvc_poll(struct hvc_struct
*hp
)
528 struct tty_struct
*tty
;
529 int i
, n
, poll_mask
= 0;
530 char buf
[N_INBUF
] __ALIGNED__
;
534 spin_lock_irqsave(&hp
->lock
, flags
);
536 /* Push pending writes */
537 if (hp
->n_outbuf
> 0)
539 /* Reschedule us if still some write pending */
540 if (hp
->n_outbuf
> 0)
541 poll_mask
|= HVC_POLL_WRITE
;
543 /* No tty attached, just skip */
548 /* Now check if we can get data (are we throttled ?) */
549 if (test_bit(TTY_THROTTLED
, &tty
->flags
))
552 /* If we aren't interrupt driven and aren't throttled, we always
553 * request a reschedule
555 if (hp
->irq
== NO_IRQ
)
556 poll_mask
|= HVC_POLL_READ
;
558 /* Read data if any */
561 if (count
> (TTY_FLIPBUF_SIZE
- tty
->flip
.count
))
562 count
= TTY_FLIPBUF_SIZE
- tty
->flip
.count
;
564 /* If flip is full, just reschedule a later read */
566 poll_mask
|= HVC_POLL_READ
;
570 n
= hvc_get_chars(hp
->vtermno
, buf
, count
);
572 /* Hangup the tty when disconnected from host */
574 spin_unlock_irqrestore(&hp
->lock
, flags
);
576 spin_lock_irqsave(&hp
->lock
, flags
);
580 for (i
= 0; i
< n
; ++i
) {
581 #ifdef CONFIG_MAGIC_SYSRQ
582 if (hp
->index
== hvc_con_driver
.index
) {
583 /* Handle the SysRq Hack */
584 /* XXX should support a sequence */
585 if (buf
[i
] == '\x0f') { /* ^O */
588 } else if (sysrq_pressed
) {
589 handle_sysrq(buf
[i
], NULL
, tty
);
594 #endif /* CONFIG_MAGIC_SYSRQ */
595 tty_insert_flip_char(tty
, buf
[i
], 0);
599 tty_schedule_flip(tty
);
602 * Account for the total amount read in one loop, and if above
603 * 64 bytes, we do a quick schedule loop to let the tty grok
604 * the data and eventually throttle us.
607 if (read_total
>= 64) {
608 poll_mask
|= HVC_POLL_QUICK
;
613 /* Wakeup write queue if necessary */
619 spin_unlock_irqrestore(&hp
->lock
, flags
);
624 #if defined(CONFIG_XMON) && defined(CONFIG_SMP)
625 extern cpumask_t cpus_in_xmon
;
627 static const cpumask_t cpus_in_xmon
= CPU_MASK_NONE
;
631 * This kthread is either polling or interrupt driven. This is determined by
632 * calling hvc_poll() who determines whether a console adapter support
635 int khvcd(void *unused
)
638 struct hvc_struct
*hp
;
640 __set_current_state(TASK_RUNNING
);
645 if (cpus_empty(cpus_in_xmon
)) {
646 spin_lock(&hvc_structs_lock
);
647 list_for_each_entry(hp
, &hvc_structs
, next
) {
648 poll_mask
|= hvc_poll(hp
);
650 spin_unlock(&hvc_structs_lock
);
652 poll_mask
|= HVC_POLL_READ
;
655 if (poll_mask
& HVC_POLL_QUICK
) {
659 set_current_state(TASK_INTERRUPTIBLE
);
664 msleep_interruptible(TIMEOUT
);
666 __set_current_state(TASK_RUNNING
);
667 } while (!kthread_should_stop());
672 static struct tty_operations hvc_ops
= {
676 .hangup
= hvc_hangup
,
677 .unthrottle
= hvc_unthrottle
,
678 .write_room
= hvc_write_room
,
679 .chars_in_buffer
= hvc_chars_in_buffer
,
682 /* callback when the kboject ref count reaches zero. */
683 static void destroy_hvc_struct(struct kobject
*kobj
)
685 struct hvc_struct
*hp
= container_of(kobj
, struct hvc_struct
, kobj
);
688 spin_lock(&hvc_structs_lock
);
690 spin_lock_irqsave(&hp
->lock
, flags
);
691 list_del(&(hp
->next
));
692 spin_unlock_irqrestore(&hp
->lock
, flags
);
694 spin_unlock(&hvc_structs_lock
);
699 static struct kobj_type hvc_kobj_type
= {
700 .release
= destroy_hvc_struct
,
703 static int __devinit
hvc_probe(
705 const struct vio_device_id
*id
)
707 struct hvc_struct
*hp
;
710 /* probed with invalid parameters. */
714 hp
= kmalloc(sizeof(*hp
), GFP_KERNEL
);
718 memset(hp
, 0x00, sizeof(*hp
));
719 hp
->vtermno
= dev
->unit_address
;
721 hp
->vdev
->dev
.driver_data
= hp
;
724 kobject_init(&hp
->kobj
);
725 hp
->kobj
.ktype
= &hvc_kobj_type
;
727 spin_lock_init(&hp
->lock
);
728 spin_lock(&hvc_structs_lock
);
732 * see if this vterm id matches one registered for console.
734 for (i
=0; i
< MAX_NR_HVC_CONSOLES
; i
++)
735 if (vtermnos
[i
] == hp
->vtermno
)
738 /* no matching slot, just use a counter */
739 if (i
>= MAX_NR_HVC_CONSOLES
)
744 list_add_tail(&(hp
->next
), &hvc_structs
);
745 spin_unlock(&hvc_structs_lock
);
750 static int __devexit
hvc_remove(struct vio_dev
*dev
)
752 struct hvc_struct
*hp
= dev
->dev
.driver_data
;
754 struct kobject
*kobjp
;
755 struct tty_struct
*tty
;
757 spin_lock_irqsave(&hp
->lock
, flags
);
761 if (hp
->index
< MAX_NR_HVC_CONSOLES
)
762 vtermnos
[hp
->index
] = -1;
764 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
766 spin_unlock_irqrestore(&hp
->lock
, flags
);
769 * We 'put' the instance that was grabbed when the kobject instance
770 * was intialized using kobject_init(). Let the last holder of this
771 * kobject cause it to be removed, which will probably be the tty_hangup
777 * This function call will auto chain call hvc_hangup. The tty should
778 * always be valid at this time unless a simultaneous tty close already
779 * cleaned up the hvc_struct.
786 char hvc_driver_name
[] = "hvc_console";
788 static struct vio_device_id hvc_driver_table
[] __devinitdata
= {
789 {"serial", "hvterm1"},
792 MODULE_DEVICE_TABLE(vio
, hvc_driver_table
);
794 static struct vio_driver hvc_vio_driver
= {
795 .name
= hvc_driver_name
,
796 .id_table
= hvc_driver_table
,
798 .remove
= hvc_remove
,
801 /* Driver initialization. Follow console initialization. This is where the TTY
802 * interfaces start to become available. */
803 int __init
hvc_init(void)
807 /* We need more than hvc_count adapters due to hotplug additions. */
808 hvc_driver
= alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS
);
812 hvc_driver
->owner
= THIS_MODULE
;
813 hvc_driver
->devfs_name
= "hvc/";
814 hvc_driver
->driver_name
= "hvc";
815 hvc_driver
->name
= "hvc";
816 hvc_driver
->major
= HVC_MAJOR
;
817 hvc_driver
->minor_start
= HVC_MINOR
;
818 hvc_driver
->type
= TTY_DRIVER_TYPE_SYSTEM
;
819 hvc_driver
->init_termios
= tty_std_termios
;
820 hvc_driver
->flags
= TTY_DRIVER_REAL_RAW
;
821 tty_set_operations(hvc_driver
, &hvc_ops
);
823 if (tty_register_driver(hvc_driver
))
824 panic("Couldn't register hvc console driver\n");
826 /* Always start the kthread because there can be hotplug vty adapters
828 hvc_task
= kthread_run(khvcd
, NULL
, "khvcd");
829 if (IS_ERR(hvc_task
)) {
830 panic("Couldn't create kthread for console.\n");
831 put_tty_driver(hvc_driver
);
835 /* Register as a vio device to receive callbacks */
836 rc
= vio_register_driver(&hvc_vio_driver
);
840 module_init(hvc_init
);
842 /* This isn't particularily necessary due to this being a console driver
843 * but it is nice to be thorough.
845 static void __exit
hvc_exit(void)
847 kthread_stop(hvc_task
);
849 vio_unregister_driver(&hvc_vio_driver
);
850 tty_unregister_driver(hvc_driver
);
851 /* return tty_struct instances allocated in hvc_init(). */
852 put_tty_driver(hvc_driver
);
853 unregister_console(&hvc_con_driver
);
855 module_exit(hvc_exit
);