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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/hvc_console.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/char/hvc_console.c')
-rw-r--r--drivers/char/hvc_console.c831
1 files changed, 831 insertions, 0 deletions
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
new file mode 100644
index 000000000000..88cd858f74d0
--- /dev/null
+++ b/drivers/char/hvc_console.c
@@ -0,0 +1,831 @@
1/*
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
6 *
7 * Additional Author(s):
8 * Ryan S. Arnold <rsa@us.ibm.com>
9 *
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.
14 *
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.
19 *
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
23 */
24
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/kobject.h>
31#include <linux/kthread.h>
32#include <linux/list.h>
33#include <linux/module.h>
34#include <linux/major.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 <asm/uaccess.h>
42#include <asm/hvconsole.h>
43#include <asm/vio.h>
44
45#define HVC_MAJOR 229
46#define HVC_MINOR 0
47
48#define TIMEOUT (10)
49
50/*
51 * Wait this long per iteration while trying to push buffered data to the
52 * hypervisor before allowing the tty to complete a close operation.
53 */
54#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
55
56/*
57 * The Linux TTY code does not support dynamic addition of tty derived devices
58 * so we need to know how many tty devices we might need when space is allocated
59 * for the tty device. Since this driver supports hotplug of vty adapters we
60 * need to make sure we have enough allocated.
61 */
62#define HVC_ALLOC_TTY_ADAPTERS 8
63
64static struct tty_driver *hvc_driver;
65#ifdef CONFIG_MAGIC_SYSRQ
66static int sysrq_pressed;
67#endif
68
69#define N_OUTBUF 16
70#define N_INBUF 16
71
72#define __ALIGNED__ __attribute__((__aligned__(8)))
73
74struct hvc_struct {
75 spinlock_t lock;
76 int index;
77 struct tty_struct *tty;
78 unsigned int count;
79 int do_wakeup;
80 char outbuf[N_OUTBUF] __ALIGNED__;
81 int n_outbuf;
82 uint32_t vtermno;
83 int irq_requested;
84 int irq;
85 struct list_head next;
86 struct kobject kobj; /* ref count & hvc_struct lifetime */
87 struct vio_dev *vdev;
88};
89
90/* dynamic list of hvc_struct instances */
91static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs);
92
93/*
94 * Protect the list of hvc_struct instances from inserts and removals during
95 * list traversal.
96 */
97static DEFINE_SPINLOCK(hvc_structs_lock);
98
99/*
100 * Initial console vtermnos for console API usage prior to full console
101 * initialization. Any vty adapter outside this range will not have usable
102 * console interfaces but can still be used as a tty device. This has to be
103 * static because kmalloc will not work during early console init.
104 */
105static uint32_t vtermnos[MAX_NR_HVC_CONSOLES];
106
107/* Used for accounting purposes */
108static int num_vterms = 0;
109
110static struct task_struct *hvc_task;
111
112/*
113 * This value is used to associate a tty->index value to a hvc_struct based
114 * upon order of exposure via hvc_probe().
115 */
116static int hvc_count = -1;
117
118/* Picks up late kicks after list walk but before schedule() */
119static int hvc_kicked;
120
121/* Wake the sleeping khvcd */
122static void hvc_kick(void)
123{
124 hvc_kicked = 1;
125 wake_up_process(hvc_task);
126}
127
128/*
129 * NOTE: This API isn't used if the console adapter doesn't support interrupts.
130 * In this case the console is poll driven.
131 */
132static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
133{
134 hvc_kick();
135 return IRQ_HANDLED;
136}
137
138static void hvc_unthrottle(struct tty_struct *tty)
139{
140 hvc_kick();
141}
142
143/*
144 * Do not call this function with either the hvc_strucst_lock or the hvc_struct
145 * lock held. If successful, this function increments the kobject reference
146 * count against the target hvc_struct so it should be released when finished.
147 */
148struct hvc_struct *hvc_get_by_index(int index)
149{
150 struct hvc_struct *hp;
151 unsigned long flags;
152
153 spin_lock(&hvc_structs_lock);
154
155 list_for_each_entry(hp, &hvc_structs, next) {
156 spin_lock_irqsave(&hp->lock, flags);
157 if (hp->index == index) {
158 kobject_get(&hp->kobj);
159 spin_unlock_irqrestore(&hp->lock, flags);
160 spin_unlock(&hvc_structs_lock);
161 return hp;
162 }
163 spin_unlock_irqrestore(&hp->lock, flags);
164 }
165 hp = NULL;
166
167 spin_unlock(&hvc_structs_lock);
168 return hp;
169}
170
171/*
172 * The TTY interface won't be used until after the vio layer has exposed the vty
173 * adapter to the kernel.
174 */
175static int hvc_open(struct tty_struct *tty, struct file * filp)
176{
177 struct hvc_struct *hp;
178 unsigned long flags;
179 int irq = NO_IRQ;
180 int rc = 0;
181 struct kobject *kobjp;
182
183 /* Auto increments kobject reference if found. */
184 if (!(hp = hvc_get_by_index(tty->index))) {
185 printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n");
186 return -ENODEV;
187 }
188
189 spin_lock_irqsave(&hp->lock, flags);
190 /* Check and then increment for fast path open. */
191 if (hp->count++ > 0) {
192 spin_unlock_irqrestore(&hp->lock, flags);
193 hvc_kick();
194 return 0;
195 } /* else count == 0 */
196
197 tty->driver_data = hp;
198 hp->tty = tty;
199 /* Save for request_irq outside of spin_lock. */
200 irq = hp->irq;
201 if (irq != NO_IRQ)
202 hp->irq_requested = 1;
203
204 kobjp = &hp->kobj;
205
206 spin_unlock_irqrestore(&hp->lock, flags);
207 /* check error, fallback to non-irq */
208 if (irq != NO_IRQ)
209 rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp);
210
211 /*
212 * If the request_irq() fails and we return an error. The tty layer
213 * will call hvc_close() after a failed open but we don't want to clean
214 * up there so we'll clean up here and clear out the previously set
215 * tty fields and return the kobject reference.
216 */
217 if (rc) {
218 spin_lock_irqsave(&hp->lock, flags);
219 hp->tty = NULL;
220 hp->irq_requested = 0;
221 spin_unlock_irqrestore(&hp->lock, flags);
222 tty->driver_data = NULL;
223 kobject_put(kobjp);
224 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
225 }
226 /* Force wakeup of the polling thread */
227 hvc_kick();
228
229 return rc;
230}
231
232static void hvc_close(struct tty_struct *tty, struct file * filp)
233{
234 struct hvc_struct *hp;
235 struct kobject *kobjp;
236 int irq = NO_IRQ;
237 unsigned long flags;
238
239 if (tty_hung_up_p(filp))
240 return;
241
242 /*
243 * No driver_data means that this close was issued after a failed
244 * hvc_open by the tty layer's release_dev() function and we can just
245 * exit cleanly because the kobject reference wasn't made.
246 */
247 if (!tty->driver_data)
248 return;
249
250 hp = tty->driver_data;
251 spin_lock_irqsave(&hp->lock, flags);
252
253 kobjp = &hp->kobj;
254 if (--hp->count == 0) {
255 if (hp->irq_requested)
256 irq = hp->irq;
257 hp->irq_requested = 0;
258
259 /* We are done with the tty pointer now. */
260 hp->tty = NULL;
261 spin_unlock_irqrestore(&hp->lock, flags);
262
263 /*
264 * Chain calls chars_in_buffer() and returns immediately if
265 * there is no buffered data otherwise sleeps on a wait queue
266 * waking periodically to check chars_in_buffer().
267 */
268 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
269
270 if (irq != NO_IRQ)
271 free_irq(irq, hp);
272
273 } else {
274 if (hp->count < 0)
275 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
276 hp->vtermno, hp->count);
277 spin_unlock_irqrestore(&hp->lock, flags);
278 }
279
280 kobject_put(kobjp);
281}
282
283static void hvc_hangup(struct tty_struct *tty)
284{
285 struct hvc_struct *hp = tty->driver_data;
286 unsigned long flags;
287 int irq = NO_IRQ;
288 int temp_open_count;
289 struct kobject *kobjp;
290
291 if (!hp)
292 return;
293
294 spin_lock_irqsave(&hp->lock, flags);
295
296 /*
297 * The N_TTY line discipline has problems such that in a close vs
298 * open->hangup case this can be called after the final close so prevent
299 * that from happening for now.
300 */
301 if (hp->count <= 0) {
302 spin_unlock_irqrestore(&hp->lock, flags);
303 return;
304 }
305
306 kobjp = &hp->kobj;
307 temp_open_count = hp->count;
308 hp->count = 0;
309 hp->n_outbuf = 0;
310 hp->tty = NULL;
311 if (hp->irq_requested)
312 /* Saved for use outside of spin_lock. */
313 irq = hp->irq;
314 hp->irq_requested = 0;
315 spin_unlock_irqrestore(&hp->lock, flags);
316 if (irq != NO_IRQ)
317 free_irq(irq, hp);
318 while(temp_open_count) {
319 --temp_open_count;
320 kobject_put(kobjp);
321 }
322}
323
324/*
325 * Push buffered characters whether they were just recently buffered or waiting
326 * on a blocked hypervisor. Call this function with hp->lock held.
327 */
328static void hvc_push(struct hvc_struct *hp)
329{
330 int n;
331
332 n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
333 if (n <= 0) {
334 if (n == 0)
335 return;
336 /* throw away output on error; this happens when
337 there is no session connected to the vterm. */
338 hp->n_outbuf = 0;
339 } else
340 hp->n_outbuf -= n;
341 if (hp->n_outbuf > 0)
342 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
343 else
344 hp->do_wakeup = 1;
345}
346
347static inline int __hvc_write_kernel(struct hvc_struct *hp,
348 const unsigned char *buf, int count)
349{
350 unsigned long flags;
351 int rsize, written = 0;
352
353 spin_lock_irqsave(&hp->lock, flags);
354
355 /* Push pending writes */
356 if (hp->n_outbuf > 0)
357 hvc_push(hp);
358
359 while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) {
360 if (rsize > count)
361 rsize = count;
362 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
363 count -= rsize;
364 buf += rsize;
365 hp->n_outbuf += rsize;
366 written += rsize;
367 hvc_push(hp);
368 }
369 spin_unlock_irqrestore(&hp->lock, flags);
370
371 return written;
372}
373static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
374{
375 struct hvc_struct *hp = tty->driver_data;
376 int written;
377
378 /* This write was probably executed during a tty close. */
379 if (!hp)
380 return -EPIPE;
381
382 if (hp->count <= 0)
383 return -EIO;
384
385 written = __hvc_write_kernel(hp, buf, count);
386
387 /*
388 * Racy, but harmless, kick thread if there is still pending data.
389 * There really is nothing wrong with kicking the thread, even if there
390 * is no buffered data.
391 */
392 if (hp->n_outbuf)
393 hvc_kick();
394
395 return written;
396}
397
398/*
399 * This is actually a contract between the driver and the tty layer outlining
400 * how much write room the driver can guarentee will be sent OR BUFFERED. This
401 * driver MUST honor the return value.
402 */
403static int hvc_write_room(struct tty_struct *tty)
404{
405 struct hvc_struct *hp = tty->driver_data;
406
407 if (!hp)
408 return -1;
409
410 return N_OUTBUF - hp->n_outbuf;
411}
412
413static int hvc_chars_in_buffer(struct tty_struct *tty)
414{
415 struct hvc_struct *hp = tty->driver_data;
416
417 if (!hp)
418 return -1;
419 return hp->n_outbuf;
420}
421
422#define HVC_POLL_READ 0x00000001
423#define HVC_POLL_WRITE 0x00000002
424#define HVC_POLL_QUICK 0x00000004
425
426static int hvc_poll(struct hvc_struct *hp)
427{
428 struct tty_struct *tty;
429 int i, n, poll_mask = 0;
430 char buf[N_INBUF] __ALIGNED__;
431 unsigned long flags;
432 int read_total = 0;
433
434 spin_lock_irqsave(&hp->lock, flags);
435
436 /* Push pending writes */
437 if (hp->n_outbuf > 0)
438 hvc_push(hp);
439 /* Reschedule us if still some write pending */
440 if (hp->n_outbuf > 0)
441 poll_mask |= HVC_POLL_WRITE;
442
443 /* No tty attached, just skip */
444 tty = hp->tty;
445 if (tty == NULL)
446 goto bail;
447
448 /* Now check if we can get data (are we throttled ?) */
449 if (test_bit(TTY_THROTTLED, &tty->flags))
450 goto throttled;
451
452 /* If we aren't interrupt driven and aren't throttled, we always
453 * request a reschedule
454 */
455 if (hp->irq == NO_IRQ)
456 poll_mask |= HVC_POLL_READ;
457
458 /* Read data if any */
459 for (;;) {
460 int count = N_INBUF;
461 if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
462 count = TTY_FLIPBUF_SIZE - tty->flip.count;
463
464 /* If flip is full, just reschedule a later read */
465 if (count == 0) {
466 poll_mask |= HVC_POLL_READ;
467 break;
468 }
469
470 n = hvc_get_chars(hp->vtermno, buf, count);
471 if (n <= 0) {
472 /* Hangup the tty when disconnected from host */
473 if (n == -EPIPE) {
474 spin_unlock_irqrestore(&hp->lock, flags);
475 tty_hangup(tty);
476 spin_lock_irqsave(&hp->lock, flags);
477 }
478 break;
479 }
480 for (i = 0; i < n; ++i) {
481#ifdef CONFIG_MAGIC_SYSRQ
482 /* Handle the SysRq Hack */
483 if (buf[i] == '\x0f') { /* ^O -- should support a sequence */
484 sysrq_pressed = 1;
485 continue;
486 } else if (sysrq_pressed) {
487 handle_sysrq(buf[i], NULL, tty);
488 sysrq_pressed = 0;
489 continue;
490 }
491#endif /* CONFIG_MAGIC_SYSRQ */
492 tty_insert_flip_char(tty, buf[i], 0);
493 }
494
495 if (tty->flip.count)
496 tty_schedule_flip(tty);
497
498 /*
499 * Account for the total amount read in one loop, and if above
500 * 64 bytes, we do a quick schedule loop to let the tty grok the
501 * data and eventually throttle us.
502 */
503 read_total += n;
504 if (read_total >= 64) {
505 poll_mask |= HVC_POLL_QUICK;
506 break;
507 }
508 }
509 throttled:
510 /* Wakeup write queue if necessary */
511 if (hp->do_wakeup) {
512 hp->do_wakeup = 0;
513 tty_wakeup(tty);
514 }
515 bail:
516 spin_unlock_irqrestore(&hp->lock, flags);
517
518 return poll_mask;
519}
520
521#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
522extern cpumask_t cpus_in_xmon;
523#else
524static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
525#endif
526
527/*
528 * This kthread is either polling or interrupt driven. This is determined by
529 * calling hvc_poll() who determines whether a console adapter support
530 * interrupts.
531 */
532int khvcd(void *unused)
533{
534 int poll_mask;
535 struct hvc_struct *hp;
536
537 __set_current_state(TASK_RUNNING);
538 do {
539 poll_mask = 0;
540 hvc_kicked = 0;
541 wmb();
542 if (cpus_empty(cpus_in_xmon)) {
543 spin_lock(&hvc_structs_lock);
544 list_for_each_entry(hp, &hvc_structs, next) {
545 /*hp = list_entry(node, struct hvc_struct, * next); */
546 poll_mask |= hvc_poll(hp);
547 }
548 spin_unlock(&hvc_structs_lock);
549 } else
550 poll_mask |= HVC_POLL_READ;
551 if (hvc_kicked)
552 continue;
553 if (poll_mask & HVC_POLL_QUICK) {
554 yield();
555 continue;
556 }
557 set_current_state(TASK_INTERRUPTIBLE);
558 if (!hvc_kicked) {
559 if (poll_mask == 0)
560 schedule();
561 else
562 msleep_interruptible(TIMEOUT);
563 }
564 __set_current_state(TASK_RUNNING);
565 } while (!kthread_should_stop());
566
567 return 0;
568}
569
570static struct tty_operations hvc_ops = {
571 .open = hvc_open,
572 .close = hvc_close,
573 .write = hvc_write,
574 .hangup = hvc_hangup,
575 .unthrottle = hvc_unthrottle,
576 .write_room = hvc_write_room,
577 .chars_in_buffer = hvc_chars_in_buffer,
578};
579
580char hvc_driver_name[] = "hvc_console";
581
582static struct vio_device_id hvc_driver_table[] __devinitdata= {
583 {"serial", "hvterm1"},
584 { NULL, }
585};
586MODULE_DEVICE_TABLE(vio, hvc_driver_table);
587
588/* callback when the kboject ref count reaches zero. */
589static void destroy_hvc_struct(struct kobject *kobj)
590{
591 struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
592 unsigned long flags;
593
594 spin_lock(&hvc_structs_lock);
595
596 spin_lock_irqsave(&hp->lock, flags);
597 list_del(&(hp->next));
598 spin_unlock_irqrestore(&hp->lock, flags);
599
600 spin_unlock(&hvc_structs_lock);
601
602 kfree(hp);
603}
604
605static struct kobj_type hvc_kobj_type = {
606 .release = destroy_hvc_struct,
607};
608
609static int __devinit hvc_probe(
610 struct vio_dev *dev,
611 const struct vio_device_id *id)
612{
613 struct hvc_struct *hp;
614
615 /* probed with invalid parameters. */
616 if (!dev || !id)
617 return -EPERM;
618
619 hp = kmalloc(sizeof(*hp), GFP_KERNEL);
620 if (!hp)
621 return -ENOMEM;
622
623 memset(hp, 0x00, sizeof(*hp));
624 hp->vtermno = dev->unit_address;
625 hp->vdev = dev;
626 hp->vdev->dev.driver_data = hp;
627 hp->irq = dev->irq;
628
629 kobject_init(&hp->kobj);
630 hp->kobj.ktype = &hvc_kobj_type;
631
632 spin_lock_init(&hp->lock);
633 spin_lock(&hvc_structs_lock);
634 hp->index = ++hvc_count;
635 list_add_tail(&(hp->next), &hvc_structs);
636 spin_unlock(&hvc_structs_lock);
637
638 return 0;
639}
640
641static int __devexit hvc_remove(struct vio_dev *dev)
642{
643 struct hvc_struct *hp = dev->dev.driver_data;
644 unsigned long flags;
645 struct kobject *kobjp;
646 struct tty_struct *tty;
647
648 spin_lock_irqsave(&hp->lock, flags);
649 tty = hp->tty;
650 kobjp = &hp->kobj;
651
652 if (hp->index < MAX_NR_HVC_CONSOLES)
653 vtermnos[hp->index] = -1;
654
655 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
656
657 spin_unlock_irqrestore(&hp->lock, flags);
658
659 /*
660 * We 'put' the instance that was grabbed when the kobject instance
661 * was intialized using kobject_init(). Let the last holder of this
662 * kobject cause it to be removed, which will probably be the tty_hangup
663 * below.
664 */
665 kobject_put(kobjp);
666
667 /*
668 * This function call will auto chain call hvc_hangup. The tty should
669 * always be valid at this time unless a simultaneous tty close already
670 * cleaned up the hvc_struct.
671 */
672 if (tty)
673 tty_hangup(tty);
674 return 0;
675}
676
677static struct vio_driver hvc_vio_driver = {
678 .name = hvc_driver_name,
679 .id_table = hvc_driver_table,
680 .probe = hvc_probe,
681 .remove = hvc_remove,
682};
683
684/* Driver initialization. Follow console initialization. This is where the TTY
685 * interfaces start to become available. */
686int __init hvc_init(void)
687{
688 int rc;
689
690 /* We need more than num_vterms adapters due to hotplug additions. */
691 hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
692 /* hvc_driver = alloc_tty_driver(num_vterms); */
693 if (!hvc_driver)
694 return -ENOMEM;
695
696 hvc_driver->owner = THIS_MODULE;
697 hvc_driver->devfs_name = "hvc/";
698 hvc_driver->driver_name = "hvc";
699 hvc_driver->name = "hvc";
700 hvc_driver->major = HVC_MAJOR;
701 hvc_driver->minor_start = HVC_MINOR;
702 hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM;
703 hvc_driver->init_termios = tty_std_termios;
704 hvc_driver->flags = TTY_DRIVER_REAL_RAW;
705 tty_set_operations(hvc_driver, &hvc_ops);
706
707 if (tty_register_driver(hvc_driver))
708 panic("Couldn't register hvc console driver\n");
709
710 /* Always start the kthread because there can be hotplug vty adapters
711 * added later. */
712 hvc_task = kthread_run(khvcd, NULL, "khvcd");
713 if (IS_ERR(hvc_task)) {
714 panic("Couldn't create kthread for console.\n");
715 put_tty_driver(hvc_driver);
716 return -EIO;
717 }
718
719 /* Register as a vio device to receive callbacks */
720 rc = vio_register_driver(&hvc_vio_driver);
721
722 return rc;
723}
724
725/* This isn't particularily necessary due to this being a console driver but it
726 * is nice to be thorough */
727static void __exit hvc_exit(void)
728{
729 kthread_stop(hvc_task);
730
731 vio_unregister_driver(&hvc_vio_driver);
732 tty_unregister_driver(hvc_driver);
733 /* return tty_struct instances allocated in hvc_init(). */
734 put_tty_driver(hvc_driver);
735}
736
737/*
738 * Console APIs, NOT TTY. These APIs are available immediately when
739 * hvc_console_setup() finds adapters.
740 */
741
742/*
743 * hvc_instantiate() is an early console discovery method which locates consoles
744 * prior to the vio subsystem discovering them. Hotplugged vty adapters do NOT
745 * get an hvc_instantiate() callback since the appear after early console init.
746 */
747int hvc_instantiate(uint32_t vtermno, int index)
748{
749 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
750 return -1;
751
752 if (vtermnos[index] != -1)
753 return -1;
754
755 vtermnos[index] = vtermno;
756 return 0;
757}
758
759void hvc_console_print(struct console *co, const char *b, unsigned count)
760{
761 char c[16] __ALIGNED__;
762 unsigned i = 0, n = 0;
763 int r, donecr = 0;
764
765 /* Console access attempt outside of acceptable console range. */
766 if (co->index >= MAX_NR_HVC_CONSOLES)
767 return;
768
769 /* This console adapter was removed so it is not useable. */
770 if (vtermnos[co->index] < 0)
771 return;
772
773 while (count > 0 || i > 0) {
774 if (count > 0 && i < sizeof(c)) {
775 if (b[n] == '\n' && !donecr) {
776 c[i++] = '\r';
777 donecr = 1;
778 } else {
779 c[i++] = b[n++];
780 donecr = 0;
781 --count;
782 }
783 } else {
784 r = hvc_put_chars(vtermnos[co->index], c, i);
785 if (r < 0) {
786 /* throw away chars on error */
787 i = 0;
788 } else if (r > 0) {
789 i -= r;
790 if (i > 0)
791 memmove(c, c+r, i);
792 }
793 }
794 }
795}
796
797static struct tty_driver *hvc_console_device(struct console *c, int *index)
798{
799 *index = c->index;
800 return hvc_driver;
801}
802
803static int __init hvc_console_setup(struct console *co, char *options)
804{
805 return 0;
806}
807
808struct console hvc_con_driver = {
809 .name = "hvc",
810 .write = hvc_console_print,
811 .device = hvc_console_device,
812 .setup = hvc_console_setup,
813 .flags = CON_PRINTBUFFER,
814 .index = -1,
815};
816
817/* Early console initialization. Preceeds driver initialization. */
818static int __init hvc_console_init(void)
819{
820 int i;
821
822 for (i=0; i<MAX_NR_HVC_CONSOLES; i++)
823 vtermnos[i] = -1;
824 num_vterms = hvc_find_vtys();
825 register_console(&hvc_con_driver);
826 return 0;
827}
828console_initcall(hvc_console_init);
829
830module_init(hvc_init);
831module_exit(hvc_exit);