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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/init.h>
33#include <linux/major.h>
34#include <linux/atomic.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 <linux/freezer.h>
42#include <linux/slab.h>
43#include <linux/serial_core.h>
44
45#include <linux/uaccess.h>
46
47#include "hvc_console.h"
48
49#define HVC_MAJOR 229
50#define HVC_MINOR 0
51
52
53
54
55
56#define HVC_CLOSE_WAIT (HZ/100)
57
58
59
60
61
62
63#define N_OUTBUF 16
64#define N_INBUF 16
65
66#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
67
68static struct tty_driver *hvc_driver;
69static struct task_struct *hvc_task;
70
71
72static int hvc_kicked;
73
74
75static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1);
76
77static int hvc_init(void);
78
79#ifdef CONFIG_MAGIC_SYSRQ
80static int sysrq_pressed;
81#endif
82
83
84static LIST_HEAD(hvc_structs);
85
86
87
88
89
90static DEFINE_SPINLOCK(hvc_structs_lock);
91
92
93
94
95
96
97static int last_hvc = -1;
98
99
100
101
102
103
104static struct hvc_struct *hvc_get_by_index(int index)
105{
106 struct hvc_struct *hp;
107 unsigned long flags;
108
109 spin_lock(&hvc_structs_lock);
110
111 list_for_each_entry(hp, &hvc_structs, next) {
112 spin_lock_irqsave(&hp->lock, flags);
113 if (hp->index == index) {
114 tty_port_get(&hp->port);
115 spin_unlock_irqrestore(&hp->lock, flags);
116 spin_unlock(&hvc_structs_lock);
117 return hp;
118 }
119 spin_unlock_irqrestore(&hp->lock, flags);
120 }
121 hp = NULL;
122
123 spin_unlock(&hvc_structs_lock);
124 return hp;
125}
126
127
128
129
130
131
132
133
134static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
135static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
136 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
137
138
139
140
141
142
143static void hvc_console_print(struct console *co, const char *b,
144 unsigned count)
145{
146 char c[N_OUTBUF] __ALIGNED__;
147 unsigned i = 0, n = 0;
148 int r, donecr = 0, index = co->index;
149
150
151 if (index >= MAX_NR_HVC_CONSOLES)
152 return;
153
154
155 if (vtermnos[index] == -1)
156 return;
157
158 while (count > 0 || i > 0) {
159 if (count > 0 && i < sizeof(c)) {
160 if (b[n] == '\n' && !donecr) {
161 c[i++] = '\r';
162 donecr = 1;
163 } else {
164 c[i++] = b[n++];
165 donecr = 0;
166 --count;
167 }
168 } else {
169 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
170 if (r <= 0) {
171
172
173 if (r != -EAGAIN)
174 i = 0;
175 } else if (r > 0) {
176 i -= r;
177 if (i > 0)
178 memmove(c, c+r, i);
179 }
180 }
181 }
182}
183
184static struct tty_driver *hvc_console_device(struct console *c, int *index)
185{
186 if (vtermnos[c->index] == -1)
187 return NULL;
188
189 *index = c->index;
190 return hvc_driver;
191}
192
193static int hvc_console_setup(struct console *co, char *options)
194{
195 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
196 return -ENODEV;
197
198 if (vtermnos[co->index] == -1)
199 return -ENODEV;
200
201 return 0;
202}
203
204static struct console hvc_console = {
205 .name = "hvc",
206 .write = hvc_console_print,
207 .device = hvc_console_device,
208 .setup = hvc_console_setup,
209 .flags = CON_PRINTBUFFER,
210 .index = -1,
211};
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228static int __init hvc_console_init(void)
229{
230 register_console(&hvc_console);
231 return 0;
232}
233console_initcall(hvc_console_init);
234
235
236static void hvc_port_destruct(struct tty_port *port)
237{
238 struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
239 unsigned long flags;
240
241 spin_lock(&hvc_structs_lock);
242
243 spin_lock_irqsave(&hp->lock, flags);
244 list_del(&(hp->next));
245 spin_unlock_irqrestore(&hp->lock, flags);
246
247 spin_unlock(&hvc_structs_lock);
248
249 kfree(hp);
250}
251
252static void hvc_check_console(int index)
253{
254
255 if (hvc_console.flags & CON_ENABLED)
256 return;
257
258
259
260
261
262 if (index == hvc_console.index)
263 register_console(&hvc_console);
264}
265
266
267
268
269
270
271
272int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
273{
274 struct hvc_struct *hp;
275
276 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
277 return -1;
278
279 if (vtermnos[index] != -1)
280 return -1;
281
282
283 hp = hvc_get_by_index(index);
284 if (hp) {
285 tty_port_put(&hp->port);
286 return -1;
287 }
288
289 vtermnos[index] = vtermno;
290 cons_ops[index] = ops;
291
292
293 if (last_hvc < index)
294 last_hvc = index;
295
296
297 hvc_check_console(index);
298
299 return 0;
300}
301EXPORT_SYMBOL_GPL(hvc_instantiate);
302
303
304void hvc_kick(void)
305{
306 hvc_kicked = 1;
307 wake_up_process(hvc_task);
308}
309EXPORT_SYMBOL_GPL(hvc_kick);
310
311static void hvc_unthrottle(struct tty_struct *tty)
312{
313 hvc_kick();
314}
315
316static int hvc_install(struct tty_driver *driver, struct tty_struct *tty)
317{
318 struct hvc_struct *hp;
319 int rc;
320
321
322 hp = hvc_get_by_index(tty->index);
323 if (!hp)
324 return -ENODEV;
325
326 tty->driver_data = hp;
327
328 rc = tty_port_install(&hp->port, driver, tty);
329 if (rc)
330 tty_port_put(&hp->port);
331 return rc;
332}
333
334
335
336
337
338static int hvc_open(struct tty_struct *tty, struct file * filp)
339{
340 struct hvc_struct *hp = tty->driver_data;
341 unsigned long flags;
342 int rc = 0;
343
344 spin_lock_irqsave(&hp->port.lock, flags);
345
346 if (hp->port.count++ > 0) {
347 spin_unlock_irqrestore(&hp->port.lock, flags);
348 hvc_kick();
349 return 0;
350 }
351 spin_unlock_irqrestore(&hp->port.lock, flags);
352
353 tty_port_tty_set(&hp->port, tty);
354
355 if (hp->ops->notifier_add)
356 rc = hp->ops->notifier_add(hp, hp->data);
357
358
359
360
361
362
363
364 if (rc) {
365 tty_port_tty_set(&hp->port, NULL);
366 tty->driver_data = NULL;
367 tty_port_put(&hp->port);
368 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
369 } else
370
371 if (C_BAUD(tty))
372 if (hp->ops->dtr_rts)
373 hp->ops->dtr_rts(hp, 1);
374
375
376 hvc_kick();
377
378 return rc;
379}
380
381static void hvc_close(struct tty_struct *tty, struct file * filp)
382{
383 struct hvc_struct *hp;
384 unsigned long flags;
385
386 if (tty_hung_up_p(filp))
387 return;
388
389
390
391
392
393
394 if (!tty->driver_data)
395 return;
396
397 hp = tty->driver_data;
398
399 spin_lock_irqsave(&hp->port.lock, flags);
400
401 if (--hp->port.count == 0) {
402 spin_unlock_irqrestore(&hp->port.lock, flags);
403
404 tty_port_tty_set(&hp->port, NULL);
405
406 if (C_HUPCL(tty))
407 if (hp->ops->dtr_rts)
408 hp->ops->dtr_rts(hp, 0);
409
410 if (hp->ops->notifier_del)
411 hp->ops->notifier_del(hp, hp->data);
412
413
414 cancel_work_sync(&hp->tty_resize);
415
416
417
418
419
420
421 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
422 } else {
423 if (hp->port.count < 0)
424 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
425 hp->vtermno, hp->port.count);
426 spin_unlock_irqrestore(&hp->port.lock, flags);
427 }
428}
429
430static void hvc_cleanup(struct tty_struct *tty)
431{
432 struct hvc_struct *hp = tty->driver_data;
433
434 tty_port_put(&hp->port);
435}
436
437static void hvc_hangup(struct tty_struct *tty)
438{
439 struct hvc_struct *hp = tty->driver_data;
440 unsigned long flags;
441
442 if (!hp)
443 return;
444
445
446 cancel_work_sync(&hp->tty_resize);
447
448 spin_lock_irqsave(&hp->port.lock, flags);
449
450
451
452
453
454
455 if (hp->port.count <= 0) {
456 spin_unlock_irqrestore(&hp->port.lock, flags);
457 return;
458 }
459
460 hp->port.count = 0;
461 spin_unlock_irqrestore(&hp->port.lock, flags);
462 tty_port_tty_set(&hp->port, NULL);
463
464 hp->n_outbuf = 0;
465
466 if (hp->ops->notifier_hangup)
467 hp->ops->notifier_hangup(hp, hp->data);
468}
469
470
471
472
473
474static int hvc_push(struct hvc_struct *hp)
475{
476 int n;
477
478 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
479 if (n <= 0) {
480 if (n == 0 || n == -EAGAIN) {
481 hp->do_wakeup = 1;
482 return 0;
483 }
484
485
486 hp->n_outbuf = 0;
487 } else
488 hp->n_outbuf -= n;
489 if (hp->n_outbuf > 0)
490 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
491 else
492 hp->do_wakeup = 1;
493
494 return n;
495}
496
497static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
498{
499 struct hvc_struct *hp = tty->driver_data;
500 unsigned long flags;
501 int rsize, written = 0;
502
503
504 if (!hp)
505 return -EPIPE;
506
507
508 if (hp->port.count <= 0)
509 return -EIO;
510
511 spin_lock_irqsave(&hp->lock, flags);
512
513
514 if (hp->n_outbuf > 0)
515 hvc_push(hp);
516
517 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
518 if (rsize > count)
519 rsize = count;
520 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
521 count -= rsize;
522 buf += rsize;
523 hp->n_outbuf += rsize;
524 written += rsize;
525 hvc_push(hp);
526 }
527 spin_unlock_irqrestore(&hp->lock, flags);
528
529
530
531
532 if (hp->n_outbuf)
533 hvc_kick();
534
535 return written;
536}
537
538
539
540
541
542
543
544
545
546
547static void hvc_set_winsz(struct work_struct *work)
548{
549 struct hvc_struct *hp;
550 unsigned long hvc_flags;
551 struct tty_struct *tty;
552 struct winsize ws;
553
554 hp = container_of(work, struct hvc_struct, tty_resize);
555
556 tty = tty_port_tty_get(&hp->port);
557 if (!tty)
558 return;
559
560 spin_lock_irqsave(&hp->lock, hvc_flags);
561 ws = hp->ws;
562 spin_unlock_irqrestore(&hp->lock, hvc_flags);
563
564 tty_do_resize(tty, &ws);
565 tty_kref_put(tty);
566}
567
568
569
570
571
572
573static int hvc_write_room(struct tty_struct *tty)
574{
575 struct hvc_struct *hp = tty->driver_data;
576
577 if (!hp)
578 return 0;
579
580 return hp->outbuf_size - hp->n_outbuf;
581}
582
583static int hvc_chars_in_buffer(struct tty_struct *tty)
584{
585 struct hvc_struct *hp = tty->driver_data;
586
587 if (!hp)
588 return 0;
589 return hp->n_outbuf;
590}
591
592
593
594
595
596
597
598
599
600#define MIN_TIMEOUT (10)
601#define MAX_TIMEOUT (2000)
602static u32 timeout = MIN_TIMEOUT;
603
604#define HVC_POLL_READ 0x00000001
605#define HVC_POLL_WRITE 0x00000002
606
607int hvc_poll(struct hvc_struct *hp)
608{
609 struct tty_struct *tty;
610 int i, n, poll_mask = 0;
611 char buf[N_INBUF] __ALIGNED__;
612 unsigned long flags;
613 int read_total = 0;
614 int written_total = 0;
615
616 spin_lock_irqsave(&hp->lock, flags);
617
618
619 if (hp->n_outbuf > 0)
620 written_total = hvc_push(hp);
621
622
623 if (hp->n_outbuf > 0) {
624 poll_mask |= HVC_POLL_WRITE;
625
626 timeout = (written_total) ? 0 : MIN_TIMEOUT;
627 }
628
629
630 tty = tty_port_tty_get(&hp->port);
631 if (tty == NULL)
632 goto bail;
633
634
635 if (tty_throttled(tty))
636 goto throttled;
637
638
639
640
641 if (!hp->irq_requested)
642 poll_mask |= HVC_POLL_READ;
643
644
645 for (;;) {
646 int count = tty_buffer_request_room(&hp->port, N_INBUF);
647
648
649 if (count == 0) {
650 poll_mask |= HVC_POLL_READ;
651 break;
652 }
653
654 n = hp->ops->get_chars(hp->vtermno, buf, count);
655 if (n <= 0) {
656
657 if (n == -EPIPE) {
658 spin_unlock_irqrestore(&hp->lock, flags);
659 tty_hangup(tty);
660 spin_lock_irqsave(&hp->lock, flags);
661 } else if ( n == -EAGAIN ) {
662
663
664
665
666
667 poll_mask |= HVC_POLL_READ;
668 }
669 break;
670 }
671 for (i = 0; i < n; ++i) {
672#ifdef CONFIG_MAGIC_SYSRQ
673 if (hp->index == hvc_console.index) {
674
675
676 if (buf[i] == '\x0f') {
677
678
679 sysrq_pressed = !sysrq_pressed;
680 if (sysrq_pressed)
681 continue;
682 } else if (sysrq_pressed) {
683 handle_sysrq(buf[i]);
684 sysrq_pressed = 0;
685 continue;
686 }
687 }
688#endif
689 tty_insert_flip_char(&hp->port, buf[i], 0);
690 }
691
692 read_total += n;
693 }
694 throttled:
695
696 if (hp->do_wakeup) {
697 hp->do_wakeup = 0;
698 tty_wakeup(tty);
699 }
700 bail:
701 spin_unlock_irqrestore(&hp->lock, flags);
702
703 if (read_total) {
704
705
706 timeout = MIN_TIMEOUT;
707
708 tty_flip_buffer_push(&hp->port);
709 }
710 tty_kref_put(tty);
711
712 return poll_mask;
713}
714EXPORT_SYMBOL_GPL(hvc_poll);
715
716
717
718
719
720
721
722
723
724
725
726void __hvc_resize(struct hvc_struct *hp, struct winsize ws)
727{
728 hp->ws = ws;
729 schedule_work(&hp->tty_resize);
730}
731EXPORT_SYMBOL_GPL(__hvc_resize);
732
733
734
735
736
737
738static int khvcd(void *unused)
739{
740 int poll_mask;
741 struct hvc_struct *hp;
742
743 set_freezable();
744 do {
745 poll_mask = 0;
746 hvc_kicked = 0;
747 try_to_freeze();
748 wmb();
749 if (!cpus_are_in_xmon()) {
750 spin_lock(&hvc_structs_lock);
751 list_for_each_entry(hp, &hvc_structs, next) {
752 poll_mask |= hvc_poll(hp);
753 }
754 spin_unlock(&hvc_structs_lock);
755 } else
756 poll_mask |= HVC_POLL_READ;
757 if (hvc_kicked)
758 continue;
759 set_current_state(TASK_INTERRUPTIBLE);
760 if (!hvc_kicked) {
761 if (poll_mask == 0)
762 schedule();
763 else {
764 unsigned long j_timeout;
765
766 if (timeout < MAX_TIMEOUT)
767 timeout += (timeout >> 6) + 1;
768
769
770
771
772
773 j_timeout = msecs_to_jiffies(timeout) + 1;
774 schedule_timeout_interruptible(j_timeout);
775 }
776 }
777 __set_current_state(TASK_RUNNING);
778 } while (!kthread_should_stop());
779
780 return 0;
781}
782
783static int hvc_tiocmget(struct tty_struct *tty)
784{
785 struct hvc_struct *hp = tty->driver_data;
786
787 if (!hp || !hp->ops->tiocmget)
788 return -EINVAL;
789 return hp->ops->tiocmget(hp);
790}
791
792static int hvc_tiocmset(struct tty_struct *tty,
793 unsigned int set, unsigned int clear)
794{
795 struct hvc_struct *hp = tty->driver_data;
796
797 if (!hp || !hp->ops->tiocmset)
798 return -EINVAL;
799 return hp->ops->tiocmset(hp, set, clear);
800}
801
802#ifdef CONFIG_CONSOLE_POLL
803static int hvc_poll_init(struct tty_driver *driver, int line, char *options)
804{
805 return 0;
806}
807
808static int hvc_poll_get_char(struct tty_driver *driver, int line)
809{
810 struct tty_struct *tty = driver->ttys[0];
811 struct hvc_struct *hp = tty->driver_data;
812 int n;
813 char ch;
814
815 n = hp->ops->get_chars(hp->vtermno, &ch, 1);
816
817 if (n <= 0)
818 return NO_POLL_CHAR;
819
820 return ch;
821}
822
823static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)
824{
825 struct tty_struct *tty = driver->ttys[0];
826 struct hvc_struct *hp = tty->driver_data;
827 int n;
828
829 do {
830 n = hp->ops->put_chars(hp->vtermno, &ch, 1);
831 } while (n <= 0);
832}
833#endif
834
835static const struct tty_operations hvc_ops = {
836 .install = hvc_install,
837 .open = hvc_open,
838 .close = hvc_close,
839 .cleanup = hvc_cleanup,
840 .write = hvc_write,
841 .hangup = hvc_hangup,
842 .unthrottle = hvc_unthrottle,
843 .write_room = hvc_write_room,
844 .chars_in_buffer = hvc_chars_in_buffer,
845 .tiocmget = hvc_tiocmget,
846 .tiocmset = hvc_tiocmset,
847#ifdef CONFIG_CONSOLE_POLL
848 .poll_init = hvc_poll_init,
849 .poll_get_char = hvc_poll_get_char,
850 .poll_put_char = hvc_poll_put_char,
851#endif
852};
853
854static const struct tty_port_operations hvc_port_ops = {
855 .destruct = hvc_port_destruct,
856};
857
858struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
859 const struct hv_ops *ops,
860 int outbuf_size)
861{
862 struct hvc_struct *hp;
863 int i;
864
865
866 if (atomic_inc_not_zero(&hvc_needs_init)) {
867 int err = hvc_init();
868 if (err)
869 return ERR_PTR(err);
870 }
871
872 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
873 GFP_KERNEL);
874 if (!hp)
875 return ERR_PTR(-ENOMEM);
876
877 hp->vtermno = vtermno;
878 hp->data = data;
879 hp->ops = ops;
880 hp->outbuf_size = outbuf_size;
881 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
882
883 tty_port_init(&hp->port);
884 hp->port.ops = &hvc_port_ops;
885
886 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
887 spin_lock_init(&hp->lock);
888 spin_lock(&hvc_structs_lock);
889
890
891
892
893
894 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
895 if (vtermnos[i] == hp->vtermno &&
896 cons_ops[i] == hp->ops)
897 break;
898
899
900 if (i >= MAX_NR_HVC_CONSOLES)
901 i = ++last_hvc;
902
903 hp->index = i;
904 cons_ops[i] = ops;
905 vtermnos[i] = vtermno;
906
907 list_add_tail(&(hp->next), &hvc_structs);
908 spin_unlock(&hvc_structs_lock);
909
910
911 hvc_check_console(i);
912
913 return hp;
914}
915EXPORT_SYMBOL_GPL(hvc_alloc);
916
917int hvc_remove(struct hvc_struct *hp)
918{
919 unsigned long flags;
920 struct tty_struct *tty;
921
922 tty = tty_port_tty_get(&hp->port);
923
924 spin_lock_irqsave(&hp->lock, flags);
925 if (hp->index < MAX_NR_HVC_CONSOLES) {
926 console_lock();
927 vtermnos[hp->index] = -1;
928 cons_ops[hp->index] = NULL;
929 console_unlock();
930 }
931
932
933
934 spin_unlock_irqrestore(&hp->lock, flags);
935
936
937
938
939
940
941
942 tty_port_put(&hp->port);
943
944
945
946
947 if (tty) {
948 tty_vhangup(tty);
949 tty_kref_put(tty);
950 }
951 return 0;
952}
953EXPORT_SYMBOL_GPL(hvc_remove);
954
955
956static int hvc_init(void)
957{
958 struct tty_driver *drv;
959 int err;
960
961
962 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
963 if (!drv) {
964 err = -ENOMEM;
965 goto out;
966 }
967
968 drv->driver_name = "hvc";
969 drv->name = "hvc";
970 drv->major = HVC_MAJOR;
971 drv->minor_start = HVC_MINOR;
972 drv->type = TTY_DRIVER_TYPE_SYSTEM;
973 drv->init_termios = tty_std_termios;
974 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
975 tty_set_operations(drv, &hvc_ops);
976
977
978
979 hvc_task = kthread_run(khvcd, NULL, "khvcd");
980 if (IS_ERR(hvc_task)) {
981 printk(KERN_ERR "Couldn't create kthread for console.\n");
982 err = PTR_ERR(hvc_task);
983 goto put_tty;
984 }
985
986 err = tty_register_driver(drv);
987 if (err) {
988 printk(KERN_ERR "Couldn't register hvc console driver\n");
989 goto stop_thread;
990 }
991
992
993
994
995
996 smp_mb();
997 hvc_driver = drv;
998 return 0;
999
1000stop_thread:
1001 kthread_stop(hvc_task);
1002 hvc_task = NULL;
1003put_tty:
1004 put_tty_driver(drv);
1005out:
1006 return err;
1007}
1008