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