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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#include <linux/serial_core.h>
43
44#include <asm/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
73static int hvc_init(void);
74
75#ifdef CONFIG_MAGIC_SYSRQ
76static int sysrq_pressed;
77#endif
78
79
80static LIST_HEAD(hvc_structs);
81
82
83
84
85
86static DEFINE_SPINLOCK(hvc_structs_lock);
87
88
89
90
91
92
93static int last_hvc = -1;
94
95
96
97
98
99
100static struct hvc_struct *hvc_get_by_index(int index)
101{
102 struct hvc_struct *hp;
103 unsigned long flags;
104
105 spin_lock(&hvc_structs_lock);
106
107 list_for_each_entry(hp, &hvc_structs, next) {
108 spin_lock_irqsave(&hp->lock, flags);
109 if (hp->index == index) {
110 tty_port_get(&hp->port);
111 spin_unlock_irqrestore(&hp->lock, flags);
112 spin_unlock(&hvc_structs_lock);
113 return hp;
114 }
115 spin_unlock_irqrestore(&hp->lock, flags);
116 }
117 hp = NULL;
118
119 spin_unlock(&hvc_structs_lock);
120 return hp;
121}
122
123
124
125
126
127
128
129
130static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
131static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
132 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
133
134
135
136
137
138
139static void hvc_console_print(struct console *co, const char *b,
140 unsigned count)
141{
142 char c[N_OUTBUF] __ALIGNED__;
143 unsigned i = 0, n = 0;
144 int r, donecr = 0, index = co->index;
145
146
147 if (index >= MAX_NR_HVC_CONSOLES)
148 return;
149
150
151 if (vtermnos[index] == -1)
152 return;
153
154 while (count > 0 || i > 0) {
155 if (count > 0 && i < sizeof(c)) {
156 if (b[n] == '\n' && !donecr) {
157 c[i++] = '\r';
158 donecr = 1;
159 } else {
160 c[i++] = b[n++];
161 donecr = 0;
162 --count;
163 }
164 } else {
165 r = cons_ops[index]->put_chars(vtermnos[index], c, i);
166 if (r <= 0) {
167
168
169 if (r != -EAGAIN)
170 i = 0;
171 } else if (r > 0) {
172 i -= r;
173 if (i > 0)
174 memmove(c, c+r, i);
175 }
176 }
177 }
178}
179
180static struct tty_driver *hvc_console_device(struct console *c, int *index)
181{
182 if (vtermnos[c->index] == -1)
183 return NULL;
184
185 *index = c->index;
186 return hvc_driver;
187}
188
189static int __init hvc_console_setup(struct console *co, char *options)
190{
191 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
192 return -ENODEV;
193
194 if (vtermnos[co->index] == -1)
195 return -ENODEV;
196
197 return 0;
198}
199
200static struct console hvc_console = {
201 .name = "hvc",
202 .write = hvc_console_print,
203 .device = hvc_console_device,
204 .setup = hvc_console_setup,
205 .flags = CON_PRINTBUFFER,
206 .index = -1,
207};
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224static int __init hvc_console_init(void)
225{
226 register_console(&hvc_console);
227 return 0;
228}
229console_initcall(hvc_console_init);
230
231
232static void hvc_port_destruct(struct tty_port *port)
233{
234 struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
235 unsigned long flags;
236
237 spin_lock(&hvc_structs_lock);
238
239 spin_lock_irqsave(&hp->lock, flags);
240 list_del(&(hp->next));
241 spin_unlock_irqrestore(&hp->lock, flags);
242
243 spin_unlock(&hvc_structs_lock);
244
245 kfree(hp);
246}
247
248static void hvc_check_console(int index)
249{
250
251 if (hvc_console.flags & CON_ENABLED)
252 return;
253
254
255
256
257
258 if (index == hvc_console.index)
259 register_console(&hvc_console);
260}
261
262
263
264
265
266
267
268int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
269{
270 struct hvc_struct *hp;
271
272 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
273 return -1;
274
275 if (vtermnos[index] != -1)
276 return -1;
277
278
279 hp = hvc_get_by_index(index);
280 if (hp) {
281 tty_port_put(&hp->port);
282 return -1;
283 }
284
285 vtermnos[index] = vtermno;
286 cons_ops[index] = ops;
287
288
289 if (last_hvc < index)
290 last_hvc = index;
291
292
293 hvc_check_console(index);
294
295 return 0;
296}
297EXPORT_SYMBOL_GPL(hvc_instantiate);
298
299
300void hvc_kick(void)
301{
302 hvc_kicked = 1;
303 wake_up_process(hvc_task);
304}
305EXPORT_SYMBOL_GPL(hvc_kick);
306
307static void hvc_unthrottle(struct tty_struct *tty)
308{
309 hvc_kick();
310}
311
312static int hvc_install(struct tty_driver *driver, struct tty_struct *tty)
313{
314 struct hvc_struct *hp;
315 int rc;
316
317
318 if (!(hp = hvc_get_by_index(tty->index)))
319 return -ENODEV;
320
321 tty->driver_data = hp;
322
323 rc = tty_port_install(&hp->port, driver, tty);
324 if (rc)
325 tty_port_put(&hp->port);
326 return rc;
327}
328
329
330
331
332
333static int hvc_open(struct tty_struct *tty, struct file * filp)
334{
335 struct hvc_struct *hp = tty->driver_data;
336 unsigned long flags;
337 int rc = 0;
338
339 spin_lock_irqsave(&hp->port.lock, flags);
340
341 if (hp->port.count++ > 0) {
342 spin_unlock_irqrestore(&hp->port.lock, flags);
343 hvc_kick();
344 return 0;
345 }
346 spin_unlock_irqrestore(&hp->port.lock, flags);
347
348 tty_port_tty_set(&hp->port, tty);
349
350 if (hp->ops->notifier_add)
351 rc = hp->ops->notifier_add(hp, hp->data);
352
353
354
355
356
357
358
359 if (rc) {
360 tty_port_tty_set(&hp->port, NULL);
361 tty->driver_data = NULL;
362 tty_port_put(&hp->port);
363 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
364 }
365
366 hvc_kick();
367
368 return rc;
369}
370
371static void hvc_close(struct tty_struct *tty, struct file * filp)
372{
373 struct hvc_struct *hp;
374 unsigned long flags;
375
376 if (tty_hung_up_p(filp))
377 return;
378
379
380
381
382
383
384 if (!tty->driver_data)
385 return;
386
387 hp = tty->driver_data;
388
389 spin_lock_irqsave(&hp->port.lock, flags);
390
391 if (--hp->port.count == 0) {
392 spin_unlock_irqrestore(&hp->port.lock, flags);
393
394 tty_port_tty_set(&hp->port, NULL);
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_from_close(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 (test_bit(TTY_THROTTLED, &tty->flags))
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 if (timeout < MAX_TIMEOUT)
751 timeout += (timeout >> 6) + 1;
752
753 msleep_interruptible(timeout);
754 }
755 }
756 __set_current_state(TASK_RUNNING);
757 } while (!kthread_should_stop());
758
759 return 0;
760}
761
762static int hvc_tiocmget(struct tty_struct *tty)
763{
764 struct hvc_struct *hp = tty->driver_data;
765
766 if (!hp || !hp->ops->tiocmget)
767 return -EINVAL;
768 return hp->ops->tiocmget(hp);
769}
770
771static int hvc_tiocmset(struct tty_struct *tty,
772 unsigned int set, unsigned int clear)
773{
774 struct hvc_struct *hp = tty->driver_data;
775
776 if (!hp || !hp->ops->tiocmset)
777 return -EINVAL;
778 return hp->ops->tiocmset(hp, set, clear);
779}
780
781#ifdef CONFIG_CONSOLE_POLL
782int hvc_poll_init(struct tty_driver *driver, int line, char *options)
783{
784 return 0;
785}
786
787static int hvc_poll_get_char(struct tty_driver *driver, int line)
788{
789 struct tty_struct *tty = driver->ttys[0];
790 struct hvc_struct *hp = tty->driver_data;
791 int n;
792 char ch;
793
794 n = hp->ops->get_chars(hp->vtermno, &ch, 1);
795
796 if (n == 0)
797 return NO_POLL_CHAR;
798
799 return ch;
800}
801
802static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)
803{
804 struct tty_struct *tty = driver->ttys[0];
805 struct hvc_struct *hp = tty->driver_data;
806 int n;
807
808 do {
809 n = hp->ops->put_chars(hp->vtermno, &ch, 1);
810 } while (n <= 0);
811}
812#endif
813
814static const struct tty_operations hvc_ops = {
815 .install = hvc_install,
816 .open = hvc_open,
817 .close = hvc_close,
818 .cleanup = hvc_cleanup,
819 .write = hvc_write,
820 .hangup = hvc_hangup,
821 .unthrottle = hvc_unthrottle,
822 .write_room = hvc_write_room,
823 .chars_in_buffer = hvc_chars_in_buffer,
824 .tiocmget = hvc_tiocmget,
825 .tiocmset = hvc_tiocmset,
826#ifdef CONFIG_CONSOLE_POLL
827 .poll_init = hvc_poll_init,
828 .poll_get_char = hvc_poll_get_char,
829 .poll_put_char = hvc_poll_put_char,
830#endif
831};
832
833static const struct tty_port_operations hvc_port_ops = {
834 .destruct = hvc_port_destruct,
835};
836
837struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
838 const struct hv_ops *ops,
839 int outbuf_size)
840{
841 struct hvc_struct *hp;
842 int i;
843
844
845 if (!hvc_driver) {
846 int err = hvc_init();
847 if (err)
848 return ERR_PTR(err);
849 }
850
851 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
852 GFP_KERNEL);
853 if (!hp)
854 return ERR_PTR(-ENOMEM);
855
856 hp->vtermno = vtermno;
857 hp->data = data;
858 hp->ops = ops;
859 hp->outbuf_size = outbuf_size;
860 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
861
862 tty_port_init(&hp->port);
863 hp->port.ops = &hvc_port_ops;
864
865 INIT_WORK(&hp->tty_resize, hvc_set_winsz);
866 spin_lock_init(&hp->lock);
867 spin_lock(&hvc_structs_lock);
868
869
870
871
872
873 for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
874 if (vtermnos[i] == hp->vtermno &&
875 cons_ops[i] == hp->ops)
876 break;
877
878
879 if (i >= MAX_NR_HVC_CONSOLES)
880 i = ++last_hvc;
881
882 hp->index = i;
883 cons_ops[i] = ops;
884 vtermnos[i] = vtermno;
885
886 list_add_tail(&(hp->next), &hvc_structs);
887 spin_unlock(&hvc_structs_lock);
888
889
890 hvc_check_console(i);
891
892 return hp;
893}
894EXPORT_SYMBOL_GPL(hvc_alloc);
895
896int hvc_remove(struct hvc_struct *hp)
897{
898 unsigned long flags;
899 struct tty_struct *tty;
900
901 tty = tty_port_tty_get(&hp->port);
902
903 spin_lock_irqsave(&hp->lock, flags);
904 if (hp->index < MAX_NR_HVC_CONSOLES) {
905 console_lock();
906 vtermnos[hp->index] = -1;
907 cons_ops[hp->index] = NULL;
908 console_unlock();
909 }
910
911
912
913 spin_unlock_irqrestore(&hp->lock, flags);
914
915
916
917
918
919
920
921 tty_port_put(&hp->port);
922
923
924
925
926 if (tty) {
927 tty_vhangup(tty);
928 tty_kref_put(tty);
929 }
930 return 0;
931}
932EXPORT_SYMBOL_GPL(hvc_remove);
933
934
935static int hvc_init(void)
936{
937 struct tty_driver *drv;
938 int err;
939
940
941 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
942 if (!drv) {
943 err = -ENOMEM;
944 goto out;
945 }
946
947 drv->driver_name = "hvc";
948 drv->name = "hvc";
949 drv->major = HVC_MAJOR;
950 drv->minor_start = HVC_MINOR;
951 drv->type = TTY_DRIVER_TYPE_SYSTEM;
952 drv->init_termios = tty_std_termios;
953 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
954 tty_set_operations(drv, &hvc_ops);
955
956
957
958 hvc_task = kthread_run(khvcd, NULL, "khvcd");
959 if (IS_ERR(hvc_task)) {
960 printk(KERN_ERR "Couldn't create kthread for console.\n");
961 err = PTR_ERR(hvc_task);
962 goto put_tty;
963 }
964
965 err = tty_register_driver(drv);
966 if (err) {
967 printk(KERN_ERR "Couldn't register hvc console driver\n");
968 goto stop_thread;
969 }
970
971
972
973
974
975 smp_mb();
976 hvc_driver = drv;
977 return 0;
978
979stop_thread:
980 kthread_stop(hvc_task);
981 hvc_task = NULL;
982put_tty:
983 put_tty_driver(drv);
984out:
985 return err;
986}
987
988
989
990
991static void __exit hvc_exit(void)
992{
993 if (hvc_driver) {
994 kthread_stop(hvc_task);
995
996 tty_unregister_driver(hvc_driver);
997
998 put_tty_driver(hvc_driver);
999 unregister_console(&hvc_console);
1000 }
1001}
1002module_exit(hvc_exit);
1003