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12#include <linux/console.h>
13#include <linux/cpumask.h>
14#include <linux/init.h>
15#include <linux/kbd_kern.h>
16#include <linux/kernel.h>
17#include <linux/kthread.h>
18#include <linux/list.h>
19#include <linux/major.h>
20#include <linux/atomic.h>
21#include <linux/sysrq.h>
22#include <linux/tty.h>
23#include <linux/tty_flip.h>
24#include <linux/sched.h>
25#include <linux/spinlock.h>
26#include <linux/delay.h>
27#include <linux/freezer.h>
28#include <linux/slab.h>
29#include <linux/serial_core.h>
30
31#include <linux/uaccess.h>
32
33#include "hvc_console.h"
34
35#define HVC_MAJOR 229
36#define HVC_MINOR 0
37
38
39
40
41
42#define HVC_CLOSE_WAIT (HZ/100)
43
44
45
46
47
48
49#define N_OUTBUF 16
50#define N_INBUF 16
51
52#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
53
54static struct tty_driver *hvc_driver;
55static struct task_struct *hvc_task;
56
57
58static int hvc_kicked;
59
60
61static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1);
62
63static int hvc_init(void);
64
65#ifdef CONFIG_MAGIC_SYSRQ
66static int sysrq_pressed;
67#endif
68
69
70static LIST_HEAD(hvc_structs);
71
72
73
74
75
76static DEFINE_SPINLOCK(hvc_structs_lock);
77
78
79
80
81
82
83static int last_hvc = -1;
84
85
86
87
88
89
90static struct hvc_struct *hvc_get_by_index(int index)
91{
92 struct hvc_struct *hp;
93 unsigned long flags;
94
95 spin_lock(&hvc_structs_lock);
96
97 list_for_each_entry(hp, &hvc_structs, next) {
98 spin_lock_irqsave(&hp->lock, flags);
99 if (hp->index == index) {
100 tty_port_get(&hp->port);
101 spin_unlock_irqrestore(&hp->lock, flags);
102 spin_unlock(&hvc_structs_lock);
103 return hp;
104 }
105 spin_unlock_irqrestore(&hp->lock, flags);
106 }
107 hp = NULL;
108
109 spin_unlock(&hvc_structs_lock);
110 return hp;
111}
112
113
114
115
116
117
118
119
120static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
121static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
122 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
123
124
125
126
127
128
129static void hvc_console_print(struct console *co, const char *b,
130 unsigned count)
131{
132 char c[N_OUTBUF] __ALIGNED__;
133 unsigned i = 0, n = 0;
134 int r, donecr = 0, index = co->index;
135
136
137 if (index >= MAX_NR_HVC_CONSOLES)
138 return;
139
140
141 if (vtermnos[index] == -1)
142 return;
143
144 while (count > 0 || i > 0) {
145 if (count > 0 && i < sizeof(c)) {
146 if (b[n] == '\n' && !donecr) {
147 c[i++] = '\r';
148 donecr = 1;
149 } else {
150 c[i++] = b[n++];
151 donecr = 0;
152 --count;
153 }
154 } else {
155 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
156 if (r <= 0) {
157
158
159 if (r != -EAGAIN)
160 i = 0;
161 } else if (r > 0) {
162 i -= r;
163 if (i > 0)
164 memmove(c, c+r, i);
165 }
166 }
167 }
168}
169
170static struct tty_driver *hvc_console_device(struct console *c, int *index)
171{
172 if (vtermnos[c->index] == -1)
173 return NULL;
174
175 *index = c->index;
176 return hvc_driver;
177}
178
179static int hvc_console_setup(struct console *co, char *options)
180{
181 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
182 return -ENODEV;
183
184 if (vtermnos[co->index] == -1)
185 return -ENODEV;
186
187 return 0;
188}
189
190static struct console hvc_console = {
191 .name = "hvc",
192 .write = hvc_console_print,
193 .device = hvc_console_device,
194 .setup = hvc_console_setup,
195 .flags = CON_PRINTBUFFER,
196 .index = -1,
197};
198
199
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205
206
207
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209
210
211
212
213
214static int __init hvc_console_init(void)
215{
216 register_console(&hvc_console);
217 return 0;
218}
219console_initcall(hvc_console_init);
220
221
222static void hvc_port_destruct(struct tty_port *port)
223{
224 struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
225 unsigned long flags;
226
227 spin_lock(&hvc_structs_lock);
228
229 spin_lock_irqsave(&hp->lock, flags);
230 list_del(&(hp->next));
231 spin_unlock_irqrestore(&hp->lock, flags);
232
233 spin_unlock(&hvc_structs_lock);
234
235 kfree(hp);
236}
237
238static void hvc_check_console(int index)
239{
240
241 if (hvc_console.flags & CON_ENABLED)
242 return;
243
244
245
246
247
248 if (index == hvc_console.index)
249 register_console(&hvc_console);
250}
251
252
253
254
255
256
257
258int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
259{
260 struct hvc_struct *hp;
261
262 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
263 return -1;
264
265 if (vtermnos[index] != -1)
266 return -1;
267
268
269 hp = hvc_get_by_index(index);
270 if (hp) {
271 tty_port_put(&hp->port);
272 return -1;
273 }
274
275 vtermnos[index] = vtermno;
276 cons_ops[index] = ops;
277
278
279 if (last_hvc < index)
280 last_hvc = index;
281
282
283 hvc_check_console(index);
284
285 return 0;
286}
287EXPORT_SYMBOL_GPL(hvc_instantiate);
288
289
290void hvc_kick(void)
291{
292 hvc_kicked = 1;
293 wake_up_process(hvc_task);
294}
295EXPORT_SYMBOL_GPL(hvc_kick);
296
297static void hvc_unthrottle(struct tty_struct *tty)
298{
299 hvc_kick();
300}
301
302static int hvc_install(struct tty_driver *driver, struct tty_struct *tty)
303{
304 struct hvc_struct *hp;
305 int rc;
306
307
308 hp = hvc_get_by_index(tty->index);
309 if (!hp)
310 return -ENODEV;
311
312 tty->driver_data = hp;
313
314 rc = tty_port_install(&hp->port, driver, tty);
315 if (rc)
316 tty_port_put(&hp->port);
317 return rc;
318}
319
320
321
322
323
324static int hvc_open(struct tty_struct *tty, struct file * filp)
325{
326 struct hvc_struct *hp = tty->driver_data;
327 unsigned long flags;
328 int rc = 0;
329
330 spin_lock_irqsave(&hp->port.lock, flags);
331
332 if (hp->port.count++ > 0) {
333 spin_unlock_irqrestore(&hp->port.lock, flags);
334 hvc_kick();
335 return 0;
336 }
337 spin_unlock_irqrestore(&hp->port.lock, flags);
338
339 tty_port_tty_set(&hp->port, tty);
340
341 if (hp->ops->notifier_add)
342 rc = hp->ops->notifier_add(hp, hp->data);
343
344
345
346
347
348
349
350 if (rc) {
351 tty_port_tty_set(&hp->port, NULL);
352 tty->driver_data = NULL;
353 tty_port_put(&hp->port);
354 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
355 } else
356
357 if (C_BAUD(tty))
358 if (hp->ops->dtr_rts)
359 hp->ops->dtr_rts(hp, 1);
360
361
362 hvc_kick();
363
364 return rc;
365}
366
367static void hvc_close(struct tty_struct *tty, struct file * filp)
368{
369 struct hvc_struct *hp;
370 unsigned long flags;
371
372 if (tty_hung_up_p(filp))
373 return;
374
375
376
377
378
379
380 if (!tty->driver_data)
381 return;
382
383 hp = tty->driver_data;
384
385 spin_lock_irqsave(&hp->port.lock, flags);
386
387 if (--hp->port.count == 0) {
388 spin_unlock_irqrestore(&hp->port.lock, flags);
389
390 tty_port_tty_set(&hp->port, NULL);
391
392 if (C_HUPCL(tty))
393 if (hp->ops->dtr_rts)
394 hp->ops->dtr_rts(hp, 0);
395
396 if (hp->ops->notifier_del)
397 hp->ops->notifier_del(hp, hp->data);
398
399
400 cancel_work_sync(&hp->tty_resize);
401
402
403
404
405
406
407 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
408 } else {
409 if (hp->port.count < 0)
410 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
411 hp->vtermno, hp->port.count);
412 spin_unlock_irqrestore(&hp->port.lock, flags);
413 }
414}
415
416static void hvc_cleanup(struct tty_struct *tty)
417{
418 struct hvc_struct *hp = tty->driver_data;
419
420 tty_port_put(&hp->port);
421}
422
423static void hvc_hangup(struct tty_struct *tty)
424{
425 struct hvc_struct *hp = tty->driver_data;
426 unsigned long flags;
427
428 if (!hp)
429 return;
430
431
432 cancel_work_sync(&hp->tty_resize);
433
434 spin_lock_irqsave(&hp->port.lock, flags);
435
436
437
438
439
440
441 if (hp->port.count <= 0) {
442 spin_unlock_irqrestore(&hp->port.lock, flags);
443 return;
444 }
445
446 hp->port.count = 0;
447 spin_unlock_irqrestore(&hp->port.lock, flags);
448 tty_port_tty_set(&hp->port, NULL);
449
450 hp->n_outbuf = 0;
451
452 if (hp->ops->notifier_hangup)
453 hp->ops->notifier_hangup(hp, hp->data);
454}
455
456
457
458
459
460static int hvc_push(struct hvc_struct *hp)
461{
462 int n;
463
464 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
465 if (n <= 0) {
466 if (n == 0 || n == -EAGAIN) {
467 hp->do_wakeup = 1;
468 return 0;
469 }
470
471
472 hp->n_outbuf = 0;
473 } else
474 hp->n_outbuf -= n;
475 if (hp->n_outbuf > 0)
476 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
477 else
478 hp->do_wakeup = 1;
479
480 return n;
481}
482
483static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
484{
485 struct hvc_struct *hp = tty->driver_data;
486 unsigned long flags;
487 int rsize, written = 0;
488
489
490 if (!hp)
491 return -EPIPE;
492
493
494 if (hp->port.count <= 0)
495 return -EIO;
496
497 spin_lock_irqsave(&hp->lock, flags);
498
499
500 if (hp->n_outbuf > 0)
501 hvc_push(hp);
502
503 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
504 if (rsize > count)
505 rsize = count;
506 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
507 count -= rsize;
508 buf += rsize;
509 hp->n_outbuf += rsize;
510 written += rsize;
511 hvc_push(hp);
512 }
513 spin_unlock_irqrestore(&hp->lock, flags);
514
515
516
517
518 if (hp->n_outbuf)
519 hvc_kick();
520
521 return written;
522}
523
524
525
526
527
528
529
530
531
532
533static void hvc_set_winsz(struct work_struct *work)
534{
535 struct hvc_struct *hp;
536 unsigned long hvc_flags;
537 struct tty_struct *tty;
538 struct winsize ws;
539
540 hp = container_of(work, struct hvc_struct, tty_resize);
541
542 tty = tty_port_tty_get(&hp->port);
543 if (!tty)
544 return;
545
546 spin_lock_irqsave(&hp->lock, hvc_flags);
547 ws = hp->ws;
548 spin_unlock_irqrestore(&hp->lock, hvc_flags);
549
550 tty_do_resize(tty, &ws);
551 tty_kref_put(tty);
552}
553
554
555
556
557
558
559static int hvc_write_room(struct tty_struct *tty)
560{
561 struct hvc_struct *hp = tty->driver_data;
562
563 if (!hp)
564 return 0;
565
566 return hp->outbuf_size - hp->n_outbuf;
567}
568
569static int hvc_chars_in_buffer(struct tty_struct *tty)
570{
571 struct hvc_struct *hp = tty->driver_data;
572
573 if (!hp)
574 return 0;
575 return hp->n_outbuf;
576}
577
578
579
580
581
582
583
584
585
586#define MIN_TIMEOUT (10)
587#define MAX_TIMEOUT (2000)
588static u32 timeout = MIN_TIMEOUT;
589
590#define HVC_POLL_READ 0x00000001
591#define HVC_POLL_WRITE 0x00000002
592
593int hvc_poll(struct hvc_struct *hp)
594{
595 struct tty_struct *tty;
596 int i, n, poll_mask = 0;
597 char buf[N_INBUF] __ALIGNED__;
598 unsigned long flags;
599 int read_total = 0;
600 int written_total = 0;
601
602 spin_lock_irqsave(&hp->lock, flags);
603
604
605 if (hp->n_outbuf > 0)
606 written_total = hvc_push(hp);
607
608
609 if (hp->n_outbuf > 0) {
610 poll_mask |= HVC_POLL_WRITE;
611
612 timeout = (written_total) ? 0 : MIN_TIMEOUT;
613 }
614
615
616 tty = tty_port_tty_get(&hp->port);
617 if (tty == NULL)
618 goto bail;
619
620
621 if (tty_throttled(tty))
622 goto throttled;
623
624
625
626
627 if (!hp->irq_requested)
628 poll_mask |= HVC_POLL_READ;
629
630
631 for (;;) {
632 int count = tty_buffer_request_room(&hp->port, N_INBUF);
633
634
635 if (count == 0) {
636 poll_mask |= HVC_POLL_READ;
637 break;
638 }
639
640 n = hp->ops->get_chars(hp->vtermno, buf, count);
641 if (n <= 0) {
642
643 if (n == -EPIPE) {
644 spin_unlock_irqrestore(&hp->lock, flags);
645 tty_hangup(tty);
646 spin_lock_irqsave(&hp->lock, flags);
647 } else if ( n == -EAGAIN ) {
648
649
650
651
652
653 poll_mask |= HVC_POLL_READ;
654 }
655 break;
656 }
657 for (i = 0; i < n; ++i) {
658#ifdef CONFIG_MAGIC_SYSRQ
659 if (hp->index == hvc_console.index) {
660
661
662 if (buf[i] == '\x0f') {
663
664
665 sysrq_pressed = !sysrq_pressed;
666 if (sysrq_pressed)
667 continue;
668 } else if (sysrq_pressed) {
669 handle_sysrq(buf[i]);
670 sysrq_pressed = 0;
671 continue;
672 }
673 }
674#endif
675 tty_insert_flip_char(&hp->port, buf[i], 0);
676 }
677
678 read_total += n;
679 }
680 throttled:
681
682 if (hp->do_wakeup) {
683 hp->do_wakeup = 0;
684 tty_wakeup(tty);
685 }
686 bail:
687 spin_unlock_irqrestore(&hp->lock, flags);
688
689 if (read_total) {
690
691
692 timeout = MIN_TIMEOUT;
693
694 tty_flip_buffer_push(&hp->port);
695 }
696 tty_kref_put(tty);
697
698 return poll_mask;
699}
700EXPORT_SYMBOL_GPL(hvc_poll);
701
702
703
704
705
706
707
708
709
710
711
712void __hvc_resize(struct hvc_struct *hp, struct winsize ws)
713{
714 hp->ws = ws;
715 schedule_work(&hp->tty_resize);
716}
717EXPORT_SYMBOL_GPL(__hvc_resize);
718
719
720
721
722
723
724static int khvcd(void *unused)
725{
726 int poll_mask;
727 struct hvc_struct *hp;
728
729 set_freezable();
730 do {
731 poll_mask = 0;
732 hvc_kicked = 0;
733 try_to_freeze();
734 wmb();
735 if (!cpus_are_in_xmon()) {
736 spin_lock(&hvc_structs_lock);
737 list_for_each_entry(hp, &hvc_structs, next) {
738 poll_mask |= hvc_poll(hp);
739 }
740 spin_unlock(&hvc_structs_lock);
741 } else
742 poll_mask |= HVC_POLL_READ;
743 if (hvc_kicked)
744 continue;
745 set_current_state(TASK_INTERRUPTIBLE);
746 if (!hvc_kicked) {
747 if (poll_mask == 0)
748 schedule();
749 else {
750 unsigned long j_timeout;
751
752 if (timeout < MAX_TIMEOUT)
753 timeout += (timeout >> 6) + 1;
754
755
756
757
758
759 j_timeout = msecs_to_jiffies(timeout) + 1;
760 schedule_timeout_interruptible(j_timeout);
761 }
762 }
763 __set_current_state(TASK_RUNNING);
764 } while (!kthread_should_stop());
765
766 return 0;
767}
768
769static int hvc_tiocmget(struct tty_struct *tty)
770{
771 struct hvc_struct *hp = tty->driver_data;
772
773 if (!hp || !hp->ops->tiocmget)
774 return -EINVAL;
775 return hp->ops->tiocmget(hp);
776}
777
778static int hvc_tiocmset(struct tty_struct *tty,
779 unsigned int set, unsigned int clear)
780{
781 struct hvc_struct *hp = tty->driver_data;
782
783 if (!hp || !hp->ops->tiocmset)
784 return -EINVAL;
785 return hp->ops->tiocmset(hp, set, clear);
786}
787
788#ifdef CONFIG_CONSOLE_POLL
789static int hvc_poll_init(struct tty_driver *driver, int line, char *options)
790{
791 return 0;
792}
793
794static int hvc_poll_get_char(struct tty_driver *driver, int line)
795{
796 struct tty_struct *tty = driver->ttys[0];
797 struct hvc_struct *hp = tty->driver_data;
798 int n;
799 char ch;
800
801 n = hp->ops->get_chars(hp->vtermno, &ch, 1);
802
803 if (n <= 0)
804 return NO_POLL_CHAR;
805
806 return ch;
807}
808
809static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)
810{
811 struct tty_struct *tty = driver->ttys[0];
812 struct hvc_struct *hp = tty->driver_data;
813 int n;
814
815 do {
816 n = hp->ops->put_chars(hp->vtermno, &ch, 1);
817 } while (n <= 0);
818}
819#endif
820
821static const struct tty_operations hvc_ops = {
822 .install = hvc_install,
823 .open = hvc_open,
824 .close = hvc_close,
825 .cleanup = hvc_cleanup,
826 .write = hvc_write,
827 .hangup = hvc_hangup,
828 .unthrottle = hvc_unthrottle,
829 .write_room = hvc_write_room,
830 .chars_in_buffer = hvc_chars_in_buffer,
831 .tiocmget = hvc_tiocmget,
832 .tiocmset = hvc_tiocmset,
833#ifdef CONFIG_CONSOLE_POLL
834 .poll_init = hvc_poll_init,
835 .poll_get_char = hvc_poll_get_char,
836 .poll_put_char = hvc_poll_put_char,
837#endif
838};
839
840static const struct tty_port_operations hvc_port_ops = {
841 .destruct = hvc_port_destruct,
842};
843
844struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
845 const struct hv_ops *ops,
846 int outbuf_size)
847{
848 struct hvc_struct *hp;
849 int i;
850
851
852 if (atomic_inc_not_zero(&hvc_needs_init)) {
853 int err = hvc_init();
854 if (err)
855 return ERR_PTR(err);
856 }
857
858 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
859 GFP_KERNEL);
860 if (!hp)
861 return ERR_PTR(-ENOMEM);
862
863 hp->vtermno = vtermno;
864 hp->data = data;
865 hp->ops = ops;
866 hp->outbuf_size = outbuf_size;
867 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
868
869 tty_port_init(&hp->port);
870 hp->port.ops = &hvc_port_ops;
871
872 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
873 spin_lock_init(&hp->lock);
874 spin_lock(&hvc_structs_lock);
875
876
877
878
879
880 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
881 if (vtermnos[i] == hp->vtermno &&
882 cons_ops[i] == hp->ops)
883 break;
884
885
886 if (i >= MAX_NR_HVC_CONSOLES)
887 i = ++last_hvc;
888
889 hp->index = i;
890 cons_ops[i] = ops;
891 vtermnos[i] = vtermno;
892
893 list_add_tail(&(hp->next), &hvc_structs);
894 spin_unlock(&hvc_structs_lock);
895
896
897 hvc_check_console(i);
898
899 return hp;
900}
901EXPORT_SYMBOL_GPL(hvc_alloc);
902
903int hvc_remove(struct hvc_struct *hp)
904{
905 unsigned long flags;
906 struct tty_struct *tty;
907
908 tty = tty_port_tty_get(&hp->port);
909
910 console_lock();
911 spin_lock_irqsave(&hp->lock, flags);
912 if (hp->index < MAX_NR_HVC_CONSOLES) {
913 vtermnos[hp->index] = -1;
914 cons_ops[hp->index] = NULL;
915 }
916
917
918
919 spin_unlock_irqrestore(&hp->lock, flags);
920 console_unlock();
921
922
923
924
925
926
927
928 tty_port_put(&hp->port);
929
930
931
932
933 if (tty) {
934 tty_vhangup(tty);
935 tty_kref_put(tty);
936 }
937 return 0;
938}
939EXPORT_SYMBOL_GPL(hvc_remove);
940
941
942static int hvc_init(void)
943{
944 struct tty_driver *drv;
945 int err;
946
947
948 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
949 if (!drv) {
950 err = -ENOMEM;
951 goto out;
952 }
953
954 drv->driver_name = "hvc";
955 drv->name = "hvc";
956 drv->major = HVC_MAJOR;
957 drv->minor_start = HVC_MINOR;
958 drv->type = TTY_DRIVER_TYPE_SYSTEM;
959 drv->init_termios = tty_std_termios;
960 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
961 tty_set_operations(drv, &hvc_ops);
962
963
964
965 hvc_task = kthread_run(khvcd, NULL, "khvcd");
966 if (IS_ERR(hvc_task)) {
967 printk(KERN_ERR "Couldn't create kthread for console.\n");
968 err = PTR_ERR(hvc_task);
969 goto put_tty;
970 }
971
972 err = tty_register_driver(drv);
973 if (err) {
974 printk(KERN_ERR "Couldn't register hvc console driver\n");
975 goto stop_thread;
976 }
977
978
979
980
981
982 smp_mb();
983 hvc_driver = drv;
984 return 0;
985
986stop_thread:
987 kthread_stop(hvc_task);
988 hvc_task = NULL;
989put_tty:
990 put_tty_driver(drv);
991out:
992 return err;
993}
994