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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>
41#include <linux/slab.h>
42
43#include <asm/uaccess.h>
44
45#include "hvc_console.h"
46
47#define HVC_MAJOR 229
48#define HVC_MINOR 0
49
50
51
52
53
54#define HVC_CLOSE_WAIT (HZ/100)
55
56
57
58
59
60
61#define N_OUTBUF 16
62#define N_INBUF 16
63
64#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
65
66static struct tty_driver *hvc_driver;
67static struct task_struct *hvc_task;
68
69
70static int hvc_kicked;
71
72static int hvc_init(void);
73
74#ifdef CONFIG_MAGIC_SYSRQ
75static int sysrq_pressed;
76#endif
77
78
79static LIST_HEAD(hvc_structs);
80
81
82
83
84
85static DEFINE_SPINLOCK(hvc_structs_lock);
86
87
88
89
90
91
92static int last_hvc = -1;
93
94
95
96
97
98
99static struct hvc_struct *hvc_get_by_index(int index)
100{
101 struct hvc_struct *hp;
102 unsigned long flags;
103
104 spin_lock(&hvc_structs_lock);
105
106 list_for_each_entry(hp, &hvc_structs, next) {
107 spin_lock_irqsave(&hp->lock, flags);
108 if (hp->index == index) {
109 kref_get(&hp->kref);
110 spin_unlock_irqrestore(&hp->lock, flags);
111 spin_unlock(&hvc_structs_lock);
112 return hp;
113 }
114 spin_unlock_irqrestore(&hp->lock, flags);
115 }
116 hp = NULL;
117
118 spin_unlock(&hvc_structs_lock);
119 return hp;
120}
121
122
123
124
125
126
127
128
129static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
130static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
131 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
132
133
134
135
136
137
138static void hvc_console_print(struct console *co, const char *b,
139 unsigned count)
140{
141 char c[N_OUTBUF] __ALIGNED__;
142 unsigned i = 0, n = 0;
143 int r, donecr = 0, index = co->index;
144
145
146 if (index >= MAX_NR_HVC_CONSOLES)
147 return;
148
149
150 if (vtermnos[index] == -1)
151 return;
152
153 while (count > 0 || i > 0) {
154 if (count > 0 && i < sizeof(c)) {
155 if (b[n] == '\n' && !donecr) {
156 c[i++] = '\r';
157 donecr = 1;
158 } else {
159 c[i++] = b[n++];
160 donecr = 0;
161 --count;
162 }
163 } else {
164 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
165 if (r <= 0) {
166
167 i = 0;
168 } else if (r > 0) {
169 i -= r;
170 if (i > 0)
171 memmove(c, c+r, i);
172 }
173 }
174 }
175}
176
177static struct tty_driver *hvc_console_device(struct console *c, int *index)
178{
179 if (vtermnos[c->index] == -1)
180 return NULL;
181
182 *index = c->index;
183 return hvc_driver;
184}
185
186static int __init hvc_console_setup(struct console *co, char *options)
187{
188 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
189 return -ENODEV;
190
191 if (vtermnos[co->index] == -1)
192 return -ENODEV;
193
194 return 0;
195}
196
197static struct console hvc_console = {
198 .name = "hvc",
199 .write = hvc_console_print,
200 .device = hvc_console_device,
201 .setup = hvc_console_setup,
202 .flags = CON_PRINTBUFFER,
203 .index = -1,
204};
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221static int __init hvc_console_init(void)
222{
223 register_console(&hvc_console);
224 return 0;
225}
226console_initcall(hvc_console_init);
227
228
229static void destroy_hvc_struct(struct kref *kref)
230{
231 struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref);
232 unsigned long flags;
233
234 spin_lock(&hvc_structs_lock);
235
236 spin_lock_irqsave(&hp->lock, flags);
237 list_del(&(hp->next));
238 spin_unlock_irqrestore(&hp->lock, flags);
239
240 spin_unlock(&hvc_structs_lock);
241
242 kfree(hp);
243}
244
245
246
247
248
249
250
251int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
252{
253 struct hvc_struct *hp;
254
255 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
256 return -1;
257
258 if (vtermnos[index] != -1)
259 return -1;
260
261
262 hp = hvc_get_by_index(index);
263 if (hp) {
264 kref_put(&hp->kref, destroy_hvc_struct);
265 return -1;
266 }
267
268 vtermnos[index] = vtermno;
269 cons_ops[index] = ops;
270
271
272 if (last_hvc < index)
273 last_hvc = index;
274
275
276
277
278
279 if (index == hvc_console.index)
280 register_console(&hvc_console);
281
282 return 0;
283}
284EXPORT_SYMBOL_GPL(hvc_instantiate);
285
286
287void hvc_kick(void)
288{
289 hvc_kicked = 1;
290 wake_up_process(hvc_task);
291}
292EXPORT_SYMBOL_GPL(hvc_kick);
293
294static void hvc_unthrottle(struct tty_struct *tty)
295{
296 hvc_kick();
297}
298
299
300
301
302
303static int hvc_open(struct tty_struct *tty, struct file * filp)
304{
305 struct hvc_struct *hp;
306 unsigned long flags;
307 int rc = 0;
308
309
310 if (!(hp = hvc_get_by_index(tty->index)))
311 return -ENODEV;
312
313 spin_lock_irqsave(&hp->lock, flags);
314
315 if (hp->count++ > 0) {
316 tty_kref_get(tty);
317 spin_unlock_irqrestore(&hp->lock, flags);
318 hvc_kick();
319 return 0;
320 }
321
322 tty->driver_data = hp;
323
324 hp->tty = tty_kref_get(tty);
325
326 spin_unlock_irqrestore(&hp->lock, flags);
327
328 if (hp->ops->notifier_add)
329 rc = hp->ops->notifier_add(hp, hp->data);
330
331
332
333
334
335
336
337 if (rc) {
338 spin_lock_irqsave(&hp->lock, flags);
339 hp->tty = NULL;
340 spin_unlock_irqrestore(&hp->lock, flags);
341 tty_kref_put(tty);
342 tty->driver_data = NULL;
343 kref_put(&hp->kref, destroy_hvc_struct);
344 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
345 }
346
347 hvc_kick();
348
349 return rc;
350}
351
352static void hvc_close(struct tty_struct *tty, struct file * filp)
353{
354 struct hvc_struct *hp;
355 unsigned long flags;
356
357 if (tty_hung_up_p(filp))
358 return;
359
360
361
362
363
364
365 if (!tty->driver_data)
366 return;
367
368 hp = tty->driver_data;
369
370 spin_lock_irqsave(&hp->lock, flags);
371
372 if (--hp->count == 0) {
373
374 hp->tty = NULL;
375 spin_unlock_irqrestore(&hp->lock, flags);
376
377 if (hp->ops->notifier_del)
378 hp->ops->notifier_del(hp, hp->data);
379
380
381 cancel_work_sync(&hp->tty_resize);
382
383
384
385
386
387
388 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
389 } else {
390 if (hp->count < 0)
391 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
392 hp->vtermno, hp->count);
393 spin_unlock_irqrestore(&hp->lock, flags);
394 }
395
396 tty_kref_put(tty);
397 kref_put(&hp->kref, destroy_hvc_struct);
398}
399
400static void hvc_hangup(struct tty_struct *tty)
401{
402 struct hvc_struct *hp = tty->driver_data;
403 unsigned long flags;
404 int temp_open_count;
405
406 if (!hp)
407 return;
408
409
410 cancel_work_sync(&hp->tty_resize);
411
412 spin_lock_irqsave(&hp->lock, flags);
413
414
415
416
417
418
419 if (hp->count <= 0) {
420 spin_unlock_irqrestore(&hp->lock, flags);
421 return;
422 }
423
424 temp_open_count = hp->count;
425 hp->count = 0;
426 hp->n_outbuf = 0;
427 hp->tty = NULL;
428
429 spin_unlock_irqrestore(&hp->lock, flags);
430
431 if (hp->ops->notifier_hangup)
432 hp->ops->notifier_hangup(hp, hp->data);
433
434 while(temp_open_count) {
435 --temp_open_count;
436 tty_kref_put(tty);
437 kref_put(&hp->kref, destroy_hvc_struct);
438 }
439}
440
441
442
443
444
445static int hvc_push(struct hvc_struct *hp)
446{
447 int n;
448
449 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
450 if (n <= 0) {
451 if (n == 0) {
452 hp->do_wakeup = 1;
453 return 0;
454 }
455
456
457 hp->n_outbuf = 0;
458 } else
459 hp->n_outbuf -= n;
460 if (hp->n_outbuf > 0)
461 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
462 else
463 hp->do_wakeup = 1;
464
465 return n;
466}
467
468static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
469{
470 struct hvc_struct *hp = tty->driver_data;
471 unsigned long flags;
472 int rsize, written = 0;
473
474
475 if (!hp)
476 return -EPIPE;
477
478 if (hp->count <= 0)
479 return -EIO;
480
481 spin_lock_irqsave(&hp->lock, flags);
482
483
484 if (hp->n_outbuf > 0)
485 hvc_push(hp);
486
487 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
488 if (rsize > count)
489 rsize = count;
490 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
491 count -= rsize;
492 buf += rsize;
493 hp->n_outbuf += rsize;
494 written += rsize;
495 hvc_push(hp);
496 }
497 spin_unlock_irqrestore(&hp->lock, flags);
498
499
500
501
502 if (hp->n_outbuf)
503 hvc_kick();
504
505 return written;
506}
507
508
509
510
511
512
513
514
515
516
517static void hvc_set_winsz(struct work_struct *work)
518{
519 struct hvc_struct *hp;
520 unsigned long hvc_flags;
521 struct tty_struct *tty;
522 struct winsize ws;
523
524 hp = container_of(work, struct hvc_struct, tty_resize);
525
526 spin_lock_irqsave(&hp->lock, hvc_flags);
527 if (!hp->tty) {
528 spin_unlock_irqrestore(&hp->lock, hvc_flags);
529 return;
530 }
531 ws = hp->ws;
532 tty = tty_kref_get(hp->tty);
533 spin_unlock_irqrestore(&hp->lock, hvc_flags);
534
535 tty_do_resize(tty, &ws);
536 tty_kref_put(tty);
537}
538
539
540
541
542
543
544static int hvc_write_room(struct tty_struct *tty)
545{
546 struct hvc_struct *hp = tty->driver_data;
547
548 if (!hp)
549 return -1;
550
551 return hp->outbuf_size - hp->n_outbuf;
552}
553
554static int hvc_chars_in_buffer(struct tty_struct *tty)
555{
556 struct hvc_struct *hp = tty->driver_data;
557
558 if (!hp)
559 return 0;
560 return hp->n_outbuf;
561}
562
563
564
565
566
567
568
569
570
571#define MIN_TIMEOUT (10)
572#define MAX_TIMEOUT (2000)
573static u32 timeout = MIN_TIMEOUT;
574
575#define HVC_POLL_READ 0x00000001
576#define HVC_POLL_WRITE 0x00000002
577
578int hvc_poll(struct hvc_struct *hp)
579{
580 struct tty_struct *tty;
581 int i, n, poll_mask = 0;
582 char buf[N_INBUF] __ALIGNED__;
583 unsigned long flags;
584 int read_total = 0;
585 int written_total = 0;
586
587 spin_lock_irqsave(&hp->lock, flags);
588
589
590 if (hp->n_outbuf > 0)
591 written_total = hvc_push(hp);
592
593
594 if (hp->n_outbuf > 0) {
595 poll_mask |= HVC_POLL_WRITE;
596
597 timeout = (written_total) ? 0 : MIN_TIMEOUT;
598 }
599
600
601 tty = tty_kref_get(hp->tty);
602 if (tty == NULL)
603 goto bail;
604
605
606 if (test_bit(TTY_THROTTLED, &tty->flags))
607 goto throttled;
608
609
610
611
612 if (!hp->irq_requested)
613 poll_mask |= HVC_POLL_READ;
614
615
616 for (;;) {
617 int count = tty_buffer_request_room(tty, N_INBUF);
618
619
620 if (count == 0) {
621 poll_mask |= HVC_POLL_READ;
622 break;
623 }
624
625 n = hp->ops->get_chars(hp->vtermno, buf, count);
626 if (n <= 0) {
627
628 if (n == -EPIPE) {
629 spin_unlock_irqrestore(&hp->lock, flags);
630 tty_hangup(tty);
631 spin_lock_irqsave(&hp->lock, flags);
632 } else if ( n == -EAGAIN ) {
633
634
635
636
637
638 poll_mask |= HVC_POLL_READ;
639 }
640 break;
641 }
642 for (i = 0; i < n; ++i) {
643#ifdef CONFIG_MAGIC_SYSRQ
644 if (hp->index == hvc_console.index) {
645
646
647 if (buf[i] == '\x0f') {
648
649
650 sysrq_pressed = !sysrq_pressed;
651 if (sysrq_pressed)
652 continue;
653 } else if (sysrq_pressed) {
654 handle_sysrq(buf[i]);
655 sysrq_pressed = 0;
656 continue;
657 }
658 }
659#endif
660 tty_insert_flip_char(tty, buf[i], 0);
661 }
662
663 read_total += n;
664 }
665 throttled:
666
667 if (hp->do_wakeup) {
668 hp->do_wakeup = 0;
669 tty_wakeup(tty);
670 }
671 bail:
672 spin_unlock_irqrestore(&hp->lock, flags);
673
674 if (read_total) {
675
676
677 timeout = MIN_TIMEOUT;
678
679 tty_flip_buffer_push(tty);
680 }
681 if (tty)
682 tty_kref_put(tty);
683
684 return poll_mask;
685}
686EXPORT_SYMBOL_GPL(hvc_poll);
687
688
689
690
691
692
693
694
695
696
697
698void __hvc_resize(struct hvc_struct *hp, struct winsize ws)
699{
700 hp->ws = ws;
701 schedule_work(&hp->tty_resize);
702}
703EXPORT_SYMBOL_GPL(__hvc_resize);
704
705
706
707
708
709
710static int khvcd(void *unused)
711{
712 int poll_mask;
713 struct hvc_struct *hp;
714
715 set_freezable();
716 do {
717 poll_mask = 0;
718 hvc_kicked = 0;
719 try_to_freeze();
720 wmb();
721 if (!cpus_are_in_xmon()) {
722 spin_lock(&hvc_structs_lock);
723 list_for_each_entry(hp, &hvc_structs, next) {
724 poll_mask |= hvc_poll(hp);
725 }
726 spin_unlock(&hvc_structs_lock);
727 } else
728 poll_mask |= HVC_POLL_READ;
729 if (hvc_kicked)
730 continue;
731 set_current_state(TASK_INTERRUPTIBLE);
732 if (!hvc_kicked) {
733 if (poll_mask == 0)
734 schedule();
735 else {
736 if (timeout < MAX_TIMEOUT)
737 timeout += (timeout >> 6) + 1;
738
739 msleep_interruptible(timeout);
740 }
741 }
742 __set_current_state(TASK_RUNNING);
743 } while (!kthread_should_stop());
744
745 return 0;
746}
747
748static const struct tty_operations hvc_ops = {
749 .open = hvc_open,
750 .close = hvc_close,
751 .write = hvc_write,
752 .hangup = hvc_hangup,
753 .unthrottle = hvc_unthrottle,
754 .write_room = hvc_write_room,
755 .chars_in_buffer = hvc_chars_in_buffer,
756};
757
758struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
759 const struct hv_ops *ops,
760 int outbuf_size)
761{
762 struct hvc_struct *hp;
763 int i;
764
765
766 if (!hvc_driver) {
767 int err = hvc_init();
768 if (err)
769 return ERR_PTR(err);
770 }
771
772 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
773 GFP_KERNEL);
774 if (!hp)
775 return ERR_PTR(-ENOMEM);
776
777 hp->vtermno = vtermno;
778 hp->data = data;
779 hp->ops = ops;
780 hp->outbuf_size = outbuf_size;
781 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
782
783 kref_init(&hp->kref);
784
785 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
786 spin_lock_init(&hp->lock);
787 spin_lock(&hvc_structs_lock);
788
789
790
791
792
793 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
794 if (vtermnos[i] == hp->vtermno &&
795 cons_ops[i] == hp->ops)
796 break;
797
798
799 if (i >= MAX_NR_HVC_CONSOLES)
800 i = ++last_hvc;
801
802 hp->index = i;
803
804 list_add_tail(&(hp->next), &hvc_structs);
805 spin_unlock(&hvc_structs_lock);
806
807 return hp;
808}
809EXPORT_SYMBOL_GPL(hvc_alloc);
810
811int hvc_remove(struct hvc_struct *hp)
812{
813 unsigned long flags;
814 struct tty_struct *tty;
815
816 spin_lock_irqsave(&hp->lock, flags);
817 tty = tty_kref_get(hp->tty);
818
819 if (hp->index < MAX_NR_HVC_CONSOLES)
820 vtermnos[hp->index] = -1;
821
822
823
824 spin_unlock_irqrestore(&hp->lock, flags);
825
826
827
828
829
830
831
832 kref_put(&hp->kref, destroy_hvc_struct);
833
834
835
836
837 if (tty) {
838 tty_vhangup(tty);
839 tty_kref_put(tty);
840 }
841 return 0;
842}
843EXPORT_SYMBOL_GPL(hvc_remove);
844
845
846static int hvc_init(void)
847{
848 struct tty_driver *drv;
849 int err;
850
851
852 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
853 if (!drv) {
854 err = -ENOMEM;
855 goto out;
856 }
857
858 drv->owner = THIS_MODULE;
859 drv->driver_name = "hvc";
860 drv->name = "hvc";
861 drv->major = HVC_MAJOR;
862 drv->minor_start = HVC_MINOR;
863 drv->type = TTY_DRIVER_TYPE_SYSTEM;
864 drv->init_termios = tty_std_termios;
865 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
866 tty_set_operations(drv, &hvc_ops);
867
868
869
870 hvc_task = kthread_run(khvcd, NULL, "khvcd");
871 if (IS_ERR(hvc_task)) {
872 printk(KERN_ERR "Couldn't create kthread for console.\n");
873 err = PTR_ERR(hvc_task);
874 goto put_tty;
875 }
876
877 err = tty_register_driver(drv);
878 if (err) {
879 printk(KERN_ERR "Couldn't register hvc console driver\n");
880 goto stop_thread;
881 }
882
883
884
885
886
887 smp_mb();
888 hvc_driver = drv;
889 return 0;
890
891stop_thread:
892 kthread_stop(hvc_task);
893 hvc_task = NULL;
894put_tty:
895 put_tty_driver(drv);
896out:
897 return err;
898}
899
900
901
902
903static void __exit hvc_exit(void)
904{
905 if (hvc_driver) {
906 kthread_stop(hvc_task);
907
908 tty_unregister_driver(hvc_driver);
909
910 put_tty_driver(hvc_driver);
911 unregister_console(&hvc_console);
912 }
913}
914module_exit(hvc_exit);
915