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1// SPDX-License-Identifier: GPL-2.0
2/* vcc.c: sun4v virtual channel concentrator
3 *
4 * Copyright (C) 2017 Oracle. All rights reserved.
5 */
6
7#include <linux/delay.h>
8#include <linux/interrupt.h>
9#include <linux/module.h>
10#include <linux/slab.h>
11#include <linux/sysfs.h>
12#include <linux/tty.h>
13#include <linux/tty_flip.h>
14#include <asm/vio.h>
15#include <asm/ldc.h>
16
17#define DRV_MODULE_NAME "vcc"
18#define DRV_MODULE_VERSION "1.1"
19#define DRV_MODULE_RELDATE "July 1, 2017"
20
21static char version[] =
22 DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")";
23
24MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
25MODULE_LICENSE("GPL");
26MODULE_VERSION(DRV_MODULE_VERSION);
27
28struct vcc_port {
29 struct vio_driver_state vio;
30
31 spinlock_t lock;
32 char *domain;
33 struct tty_struct *tty; /* only populated while dev is open */
34 unsigned long index; /* index into the vcc_table */
35
36 u64 refcnt;
37 bool excl_locked;
38
39 bool removed;
40
41 /* This buffer is required to support the tty write_room interface
42 * and guarantee that any characters that the driver accepts will
43 * be eventually sent, either immediately or later.
44 */
45 int chars_in_buffer;
46 struct vio_vcc buffer;
47
48 struct timer_list rx_timer;
49 struct timer_list tx_timer;
50};
51
52/* Microseconds that thread will delay waiting for a vcc port ref */
53#define VCC_REF_DELAY 100
54
55#define VCC_MAX_PORTS 1024
56#define VCC_MINOR_START 0 /* must be zero */
57#define VCC_BUFF_LEN VIO_VCC_MTU_SIZE
58
59#define VCC_CTL_BREAK -1
60#define VCC_CTL_HUP -2
61
62static const char vcc_driver_name[] = "vcc";
63static const char vcc_device_node[] = "vcc";
64static struct tty_driver *vcc_tty_driver;
65
66static struct vcc_port *vcc_table[VCC_MAX_PORTS];
67static DEFINE_SPINLOCK(vcc_table_lock);
68
69int vcc_dbg;
70int vcc_dbg_ldc;
71int vcc_dbg_vio;
72
73module_param(vcc_dbg, uint, 0664);
74module_param(vcc_dbg_ldc, uint, 0664);
75module_param(vcc_dbg_vio, uint, 0664);
76
77#define VCC_DBG_DRV 0x1
78#define VCC_DBG_LDC 0x2
79#define VCC_DBG_PKT 0x4
80
81#define vccdbg(f, a...) \
82 do { \
83 if (vcc_dbg & VCC_DBG_DRV) \
84 pr_info(f, ## a); \
85 } while (0) \
86
87#define vccdbgl(l) \
88 do { \
89 if (vcc_dbg & VCC_DBG_LDC) \
90 ldc_print(l); \
91 } while (0) \
92
93#define vccdbgp(pkt) \
94 do { \
95 if (vcc_dbg & VCC_DBG_PKT) { \
96 int i; \
97 for (i = 0; i < pkt.tag.stype; i++) \
98 pr_info("[%c]", pkt.data[i]); \
99 } \
100 } while (0) \
101
102/* Note: Be careful when adding flags to this line discipline. Don't
103 * add anything that will cause echoing or we'll go into recursive
104 * loop echoing chars back and forth with the console drivers.
105 */
106static const struct ktermios vcc_tty_termios = {
107 .c_iflag = IGNBRK | IGNPAR,
108 .c_oflag = OPOST,
109 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
110 .c_cc = INIT_C_CC,
111 .c_ispeed = 38400,
112 .c_ospeed = 38400
113};
114
115/**
116 * vcc_table_add() - Add VCC port to the VCC table
117 * @port: pointer to the VCC port
118 *
119 * Return: index of the port in the VCC table on success,
120 * -1 on failure
121 */
122static int vcc_table_add(struct vcc_port *port)
123{
124 unsigned long flags;
125 int i;
126
127 spin_lock_irqsave(&vcc_table_lock, flags);
128 for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
129 if (!vcc_table[i]) {
130 vcc_table[i] = port;
131 break;
132 }
133 }
134 spin_unlock_irqrestore(&vcc_table_lock, flags);
135
136 if (i < VCC_MAX_PORTS)
137 return i;
138 else
139 return -1;
140}
141
142/**
143 * vcc_table_remove() - Removes a VCC port from the VCC table
144 * @index: Index into the VCC table
145 */
146static void vcc_table_remove(unsigned long index)
147{
148 unsigned long flags;
149
150 if (WARN_ON(index >= VCC_MAX_PORTS))
151 return;
152
153 spin_lock_irqsave(&vcc_table_lock, flags);
154 vcc_table[index] = NULL;
155 spin_unlock_irqrestore(&vcc_table_lock, flags);
156}
157
158/**
159 * vcc_get() - Gets a reference to VCC port
160 * @index: Index into the VCC table
161 * @excl: Indicates if an exclusive access is requested
162 *
163 * Return: reference to the VCC port, if found
164 * NULL, if port not found
165 */
166static struct vcc_port *vcc_get(unsigned long index, bool excl)
167{
168 struct vcc_port *port;
169 unsigned long flags;
170
171try_again:
172 spin_lock_irqsave(&vcc_table_lock, flags);
173
174 port = vcc_table[index];
175 if (!port) {
176 spin_unlock_irqrestore(&vcc_table_lock, flags);
177 return NULL;
178 }
179
180 if (!excl) {
181 if (port->excl_locked) {
182 spin_unlock_irqrestore(&vcc_table_lock, flags);
183 udelay(VCC_REF_DELAY);
184 goto try_again;
185 }
186 port->refcnt++;
187 spin_unlock_irqrestore(&vcc_table_lock, flags);
188 return port;
189 }
190
191 if (port->refcnt) {
192 spin_unlock_irqrestore(&vcc_table_lock, flags);
193 /* Threads wanting exclusive access will wait half the time,
194 * probably giving them higher priority in the case of
195 * multiple waiters.
196 */
197 udelay(VCC_REF_DELAY/2);
198 goto try_again;
199 }
200
201 port->refcnt++;
202 port->excl_locked = true;
203 spin_unlock_irqrestore(&vcc_table_lock, flags);
204
205 return port;
206}
207
208/**
209 * vcc_put() - Returns a reference to VCC port
210 * @port: pointer to VCC port
211 * @excl: Indicates if the returned reference is an exclusive reference
212 *
213 * Note: It's the caller's responsibility to ensure the correct value
214 * for the excl flag
215 */
216static void vcc_put(struct vcc_port *port, bool excl)
217{
218 unsigned long flags;
219
220 if (!port)
221 return;
222
223 spin_lock_irqsave(&vcc_table_lock, flags);
224
225 /* check if caller attempted to put with the wrong flags */
226 if (WARN_ON((excl && !port->excl_locked) ||
227 (!excl && port->excl_locked)))
228 goto done;
229
230 port->refcnt--;
231
232 if (excl)
233 port->excl_locked = false;
234
235done:
236 spin_unlock_irqrestore(&vcc_table_lock, flags);
237}
238
239/**
240 * vcc_get_ne() - Get a non-exclusive reference to VCC port
241 * @index: Index into the VCC table
242 *
243 * Gets a non-exclusive reference to VCC port, if it's not removed
244 *
245 * Return: pointer to the VCC port, if found
246 * NULL, if port not found
247 */
248static struct vcc_port *vcc_get_ne(unsigned long index)
249{
250 struct vcc_port *port;
251
252 port = vcc_get(index, false);
253
254 if (port && port->removed) {
255 vcc_put(port, false);
256 return NULL;
257 }
258
259 return port;
260}
261
262static void vcc_kick_rx(struct vcc_port *port)
263{
264 struct vio_driver_state *vio = &port->vio;
265
266 assert_spin_locked(&port->lock);
267
268 if (!timer_pending(&port->rx_timer) && !port->removed) {
269 disable_irq_nosync(vio->vdev->rx_irq);
270 port->rx_timer.expires = (jiffies + 1);
271 add_timer(&port->rx_timer);
272 }
273}
274
275static void vcc_kick_tx(struct vcc_port *port)
276{
277 assert_spin_locked(&port->lock);
278
279 if (!timer_pending(&port->tx_timer) && !port->removed) {
280 port->tx_timer.expires = (jiffies + 1);
281 add_timer(&port->tx_timer);
282 }
283}
284
285static int vcc_rx_check(struct tty_struct *tty, int size)
286{
287 if (WARN_ON(!tty || !tty->port))
288 return 1;
289
290 /* tty_buffer_request_room won't sleep because it uses
291 * GFP_ATOMIC flag to allocate buffer
292 */
293 if (test_bit(TTY_THROTTLED, &tty->flags) ||
294 (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
295 return 0;
296
297 return 1;
298}
299
300static int vcc_rx(struct tty_struct *tty, char *buf, int size)
301{
302 int len = 0;
303
304 if (WARN_ON(!tty || !tty->port))
305 return len;
306
307 len = tty_insert_flip_string(tty->port, buf, size);
308 if (len)
309 tty_flip_buffer_push(tty->port);
310
311 return len;
312}
313
314static int vcc_ldc_read(struct vcc_port *port)
315{
316 struct vio_driver_state *vio = &port->vio;
317 struct tty_struct *tty;
318 struct vio_vcc pkt;
319 int rv = 0;
320
321 tty = port->tty;
322 if (!tty) {
323 rv = ldc_rx_reset(vio->lp);
324 vccdbg("VCC: reset rx q: rv=%d\n", rv);
325 goto done;
326 }
327
328 /* Read as long as LDC has incoming data. */
329 while (1) {
330 if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
331 vcc_kick_rx(port);
332 break;
333 }
334
335 vccdbgl(vio->lp);
336
337 rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
338 if (rv <= 0)
339 break;
340
341 vccdbg("VCC: ldc_read()=%d\n", rv);
342 vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
343 pkt.tag.type, pkt.tag.stype,
344 pkt.tag.stype_env, pkt.tag.sid);
345
346 if (pkt.tag.type == VIO_TYPE_DATA) {
347 vccdbgp(pkt);
348 /* vcc_rx_check ensures memory availability */
349 vcc_rx(tty, pkt.data, pkt.tag.stype);
350 } else {
351 pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
352 pkt.tag.type, pkt.tag.stype,
353 pkt.tag.stype_env, pkt.tag.sid);
354 rv = -ECONNRESET;
355 break;
356 }
357
358 WARN_ON(rv != LDC_PACKET_SIZE);
359 }
360
361done:
362 return rv;
363}
364
365static void vcc_rx_timer(struct timer_list *t)
366{
367 struct vcc_port *port = from_timer(port, t, rx_timer);
368 struct vio_driver_state *vio;
369 unsigned long flags;
370 int rv;
371
372 spin_lock_irqsave(&port->lock, flags);
373 port->rx_timer.expires = 0;
374
375 vio = &port->vio;
376
377 enable_irq(vio->vdev->rx_irq);
378
379 if (!port->tty || port->removed)
380 goto done;
381
382 rv = vcc_ldc_read(port);
383 if (rv == -ECONNRESET)
384 vio_conn_reset(vio);
385
386done:
387 spin_unlock_irqrestore(&port->lock, flags);
388 vcc_put(port, false);
389}
390
391static void vcc_tx_timer(struct timer_list *t)
392{
393 struct vcc_port *port = from_timer(port, t, tx_timer);
394 struct vio_vcc *pkt;
395 unsigned long flags;
396 int tosend = 0;
397 int rv;
398
399 spin_lock_irqsave(&port->lock, flags);
400 port->tx_timer.expires = 0;
401
402 if (!port->tty || port->removed)
403 goto done;
404
405 tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
406 if (!tosend)
407 goto done;
408
409 pkt = &port->buffer;
410 pkt->tag.type = VIO_TYPE_DATA;
411 pkt->tag.stype = tosend;
412 vccdbgl(port->vio.lp);
413
414 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
415 WARN_ON(!rv);
416
417 if (rv < 0) {
418 vccdbg("VCC: ldc_write()=%d\n", rv);
419 vcc_kick_tx(port);
420 } else {
421 struct tty_struct *tty = port->tty;
422
423 port->chars_in_buffer = 0;
424 if (tty)
425 tty_wakeup(tty);
426 }
427
428done:
429 spin_unlock_irqrestore(&port->lock, flags);
430 vcc_put(port, false);
431}
432
433/**
434 * vcc_event() - LDC event processing engine
435 * @arg: VCC private data
436 * @event: LDC event
437 *
438 * Handles LDC events for VCC
439 */
440static void vcc_event(void *arg, int event)
441{
442 struct vio_driver_state *vio;
443 struct vcc_port *port;
444 unsigned long flags;
445 int rv;
446
447 port = arg;
448 vio = &port->vio;
449
450 spin_lock_irqsave(&port->lock, flags);
451
452 switch (event) {
453 case LDC_EVENT_RESET:
454 case LDC_EVENT_UP:
455 vio_link_state_change(vio, event);
456 break;
457
458 case LDC_EVENT_DATA_READY:
459 rv = vcc_ldc_read(port);
460 if (rv == -ECONNRESET)
461 vio_conn_reset(vio);
462 break;
463
464 default:
465 pr_err("VCC: unexpected LDC event(%d)\n", event);
466 }
467
468 spin_unlock_irqrestore(&port->lock, flags);
469}
470
471static struct ldc_channel_config vcc_ldc_cfg = {
472 .event = vcc_event,
473 .mtu = VIO_VCC_MTU_SIZE,
474 .mode = LDC_MODE_RAW,
475 .debug = 0,
476};
477
478/* Ordered from largest major to lowest */
479static struct vio_version vcc_versions[] = {
480 { .major = 1, .minor = 0 },
481};
482
483static struct tty_port_operations vcc_port_ops = { 0 };
484
485static ssize_t vcc_sysfs_domain_show(struct device *dev,
486 struct device_attribute *attr,
487 char *buf)
488{
489 struct vcc_port *port;
490 int rv;
491
492 port = dev_get_drvdata(dev);
493 if (!port)
494 return -ENODEV;
495
496 rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
497
498 return rv;
499}
500
501static int vcc_send_ctl(struct vcc_port *port, int ctl)
502{
503 struct vio_vcc pkt;
504 int rv;
505
506 pkt.tag.type = VIO_TYPE_CTRL;
507 pkt.tag.sid = ctl;
508 pkt.tag.stype = 0;
509
510 rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
511 WARN_ON(!rv);
512 vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
513
514 return rv;
515}
516
517static ssize_t vcc_sysfs_break_store(struct device *dev,
518 struct device_attribute *attr,
519 const char *buf, size_t count)
520{
521 struct vcc_port *port;
522 unsigned long flags;
523 int rv = count;
524 int brk;
525
526 port = dev_get_drvdata(dev);
527 if (!port)
528 return -ENODEV;
529
530 spin_lock_irqsave(&port->lock, flags);
531
532 if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
533 rv = -EINVAL;
534 else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
535 vcc_kick_tx(port);
536
537 spin_unlock_irqrestore(&port->lock, flags);
538
539 return rv;
540}
541
542static DEVICE_ATTR(domain, 0400, vcc_sysfs_domain_show, NULL);
543static DEVICE_ATTR(break, 0200, NULL, vcc_sysfs_break_store);
544
545static struct attribute *vcc_sysfs_entries[] = {
546 &dev_attr_domain.attr,
547 &dev_attr_break.attr,
548 NULL
549};
550
551static struct attribute_group vcc_attribute_group = {
552 .name = NULL,
553 .attrs = vcc_sysfs_entries,
554};
555
556/**
557 * vcc_probe() - Initialize VCC port
558 * @vdev: Pointer to VIO device of the new VCC port
559 * @id: VIO device ID
560 *
561 * Initializes a VCC port to receive serial console data from
562 * the guest domain. Sets up a TTY end point on the control
563 * domain. Sets up VIO/LDC link between the guest & control
564 * domain endpoints.
565 *
566 * Return: status of the probe
567 */
568static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
569{
570 struct mdesc_handle *hp;
571 struct vcc_port *port;
572 struct device *dev;
573 const char *domain;
574 char *name;
575 u64 node;
576 int rv;
577
578 vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
579
580 if (!vcc_tty_driver) {
581 pr_err("VCC: TTY driver not registered\n");
582 return -ENODEV;
583 }
584
585 port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
586 if (!port)
587 return -ENOMEM;
588
589 name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
590
591 rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
592 ARRAY_SIZE(vcc_versions), NULL, name);
593 if (rv)
594 goto free_port;
595
596 port->vio.debug = vcc_dbg_vio;
597 vcc_ldc_cfg.debug = vcc_dbg_ldc;
598
599 rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
600 if (rv)
601 goto free_port;
602
603 spin_lock_init(&port->lock);
604
605 port->index = vcc_table_add(port);
606 if (port->index == -1) {
607 pr_err("VCC: no more TTY indices left for allocation\n");
608 rv = -ENOMEM;
609 goto free_ldc;
610 }
611
612 /* Register the device using VCC table index as TTY index */
613 dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
614 if (IS_ERR(dev)) {
615 rv = PTR_ERR(dev);
616 goto free_table;
617 }
618
619 hp = mdesc_grab();
620
621 node = vio_vdev_node(hp, vdev);
622 if (node == MDESC_NODE_NULL) {
623 rv = -ENXIO;
624 mdesc_release(hp);
625 goto unreg_tty;
626 }
627
628 domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
629 if (!domain) {
630 rv = -ENXIO;
631 mdesc_release(hp);
632 goto unreg_tty;
633 }
634 port->domain = kstrdup(domain, GFP_KERNEL);
635
636 mdesc_release(hp);
637
638 rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
639 if (rv)
640 goto free_domain;
641
642 timer_setup(&port->rx_timer, vcc_rx_timer, 0);
643 timer_setup(&port->tx_timer, vcc_tx_timer, 0);
644
645 dev_set_drvdata(&vdev->dev, port);
646
647 /* It's possible to receive IRQs in the middle of vio_port_up. Disable
648 * IRQs until the port is up.
649 */
650 disable_irq_nosync(vdev->rx_irq);
651 vio_port_up(&port->vio);
652 enable_irq(vdev->rx_irq);
653
654 return 0;
655
656free_domain:
657 kfree(port->domain);
658unreg_tty:
659 tty_unregister_device(vcc_tty_driver, port->index);
660free_table:
661 vcc_table_remove(port->index);
662free_ldc:
663 vio_ldc_free(&port->vio);
664free_port:
665 kfree(name);
666 kfree(port);
667
668 return rv;
669}
670
671/**
672 * vcc_remove() - Terminate a VCC port
673 * @vdev: Pointer to VIO device of the VCC port
674 *
675 * Terminates a VCC port. Sets up the teardown of TTY and
676 * VIO/LDC link between guest and primary domains.
677 *
678 * Return: status of removal
679 */
680static int vcc_remove(struct vio_dev *vdev)
681{
682 struct vcc_port *port = dev_get_drvdata(&vdev->dev);
683
684 if (!port)
685 return -ENODEV;
686
687 del_timer_sync(&port->rx_timer);
688 del_timer_sync(&port->tx_timer);
689
690 /* If there's a process with the device open, do a synchronous
691 * hangup of the TTY. This *may* cause the process to call close
692 * asynchronously, but it's not guaranteed.
693 */
694 if (port->tty)
695 tty_vhangup(port->tty);
696
697 /* Get exclusive reference to VCC, ensures that there are no other
698 * clients to this port
699 */
700 port = vcc_get(port->index, true);
701
702 if (WARN_ON(!port))
703 return -ENODEV;
704
705 tty_unregister_device(vcc_tty_driver, port->index);
706
707 del_timer_sync(&port->vio.timer);
708 vio_ldc_free(&port->vio);
709 sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
710 dev_set_drvdata(&vdev->dev, NULL);
711 if (port->tty) {
712 port->removed = true;
713 vcc_put(port, true);
714 } else {
715 vcc_table_remove(port->index);
716
717 kfree(port->vio.name);
718 kfree(port->domain);
719 kfree(port);
720 }
721
722 return 0;
723}
724
725static const struct vio_device_id vcc_match[] = {
726 {
727 .type = "vcc-port",
728 },
729 {},
730};
731MODULE_DEVICE_TABLE(vio, vcc_match);
732
733static struct vio_driver vcc_driver = {
734 .id_table = vcc_match,
735 .probe = vcc_probe,
736 .remove = vcc_remove,
737 .name = "vcc",
738};
739
740static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
741{
742 struct vcc_port *port;
743
744 if (unlikely(!tty)) {
745 pr_err("VCC: open: Invalid TTY handle\n");
746 return -ENXIO;
747 }
748
749 if (tty->count > 1)
750 return -EBUSY;
751
752 port = vcc_get_ne(tty->index);
753 if (unlikely(!port)) {
754 pr_err("VCC: open: Failed to find VCC port\n");
755 return -ENODEV;
756 }
757
758 if (unlikely(!port->vio.lp)) {
759 pr_err("VCC: open: LDC channel not configured\n");
760 vcc_put(port, false);
761 return -EPIPE;
762 }
763 vccdbgl(port->vio.lp);
764
765 vcc_put(port, false);
766
767 if (unlikely(!tty->port)) {
768 pr_err("VCC: open: TTY port not found\n");
769 return -ENXIO;
770 }
771
772 if (unlikely(!tty->port->ops)) {
773 pr_err("VCC: open: TTY ops not defined\n");
774 return -ENXIO;
775 }
776
777 return tty_port_open(tty->port, tty, vcc_file);
778}
779
780static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
781{
782 if (unlikely(!tty)) {
783 pr_err("VCC: close: Invalid TTY handle\n");
784 return;
785 }
786
787 if (unlikely(tty->count > 1))
788 return;
789
790 if (unlikely(!tty->port)) {
791 pr_err("VCC: close: TTY port not found\n");
792 return;
793 }
794
795 tty_port_close(tty->port, tty, vcc_file);
796}
797
798static void vcc_ldc_hup(struct vcc_port *port)
799{
800 unsigned long flags;
801
802 spin_lock_irqsave(&port->lock, flags);
803
804 if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
805 vcc_kick_tx(port);
806
807 spin_unlock_irqrestore(&port->lock, flags);
808}
809
810static void vcc_hangup(struct tty_struct *tty)
811{
812 struct vcc_port *port;
813
814 if (unlikely(!tty)) {
815 pr_err("VCC: hangup: Invalid TTY handle\n");
816 return;
817 }
818
819 port = vcc_get_ne(tty->index);
820 if (unlikely(!port)) {
821 pr_err("VCC: hangup: Failed to find VCC port\n");
822 return;
823 }
824
825 if (unlikely(!tty->port)) {
826 pr_err("VCC: hangup: TTY port not found\n");
827 vcc_put(port, false);
828 return;
829 }
830
831 vcc_ldc_hup(port);
832
833 vcc_put(port, false);
834
835 tty_port_hangup(tty->port);
836}
837
838static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
839 int count)
840{
841 struct vcc_port *port;
842 struct vio_vcc *pkt;
843 unsigned long flags;
844 int total_sent = 0;
845 int tosend = 0;
846 int rv = -EINVAL;
847
848 if (unlikely(!tty)) {
849 pr_err("VCC: write: Invalid TTY handle\n");
850 return -ENXIO;
851 }
852
853 port = vcc_get_ne(tty->index);
854 if (unlikely(!port)) {
855 pr_err("VCC: write: Failed to find VCC port");
856 return -ENODEV;
857 }
858
859 spin_lock_irqsave(&port->lock, flags);
860
861 pkt = &port->buffer;
862 pkt->tag.type = VIO_TYPE_DATA;
863
864 while (count > 0) {
865 /* Minimum of data to write and space available */
866 tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
867
868 if (!tosend)
869 break;
870
871 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
872 tosend);
873 port->chars_in_buffer += tosend;
874 pkt->tag.stype = tosend;
875
876 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
877 pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
878 vccdbg("DATA [%s]\n", pkt->data);
879 vccdbgl(port->vio.lp);
880
881 /* Since we know we have enough room in VCC buffer for tosend
882 * we record that it was sent regardless of whether the
883 * hypervisor actually took it because we have it buffered.
884 */
885 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
886 vccdbg("VCC: write: ldc_write(%d)=%d\n",
887 (VIO_TAG_SIZE + tosend), rv);
888
889 total_sent += tosend;
890 count -= tosend;
891 if (rv < 0) {
892 vcc_kick_tx(port);
893 break;
894 }
895
896 port->chars_in_buffer = 0;
897 }
898
899 spin_unlock_irqrestore(&port->lock, flags);
900
901 vcc_put(port, false);
902
903 vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
904
905 return total_sent ? total_sent : rv;
906}
907
908static int vcc_write_room(struct tty_struct *tty)
909{
910 struct vcc_port *port;
911 u64 num;
912
913 if (unlikely(!tty)) {
914 pr_err("VCC: write_room: Invalid TTY handle\n");
915 return -ENXIO;
916 }
917
918 port = vcc_get_ne(tty->index);
919 if (unlikely(!port)) {
920 pr_err("VCC: write_room: Failed to find VCC port\n");
921 return -ENODEV;
922 }
923
924 num = VCC_BUFF_LEN - port->chars_in_buffer;
925
926 vcc_put(port, false);
927
928 return num;
929}
930
931static int vcc_chars_in_buffer(struct tty_struct *tty)
932{
933 struct vcc_port *port;
934 u64 num;
935
936 if (unlikely(!tty)) {
937 pr_err("VCC: chars_in_buffer: Invalid TTY handle\n");
938 return -ENXIO;
939 }
940
941 port = vcc_get_ne(tty->index);
942 if (unlikely(!port)) {
943 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
944 return -ENODEV;
945 }
946
947 num = port->chars_in_buffer;
948
949 vcc_put(port, false);
950
951 return num;
952}
953
954static int vcc_break_ctl(struct tty_struct *tty, int state)
955{
956 struct vcc_port *port;
957 unsigned long flags;
958
959 if (unlikely(!tty)) {
960 pr_err("VCC: break_ctl: Invalid TTY handle\n");
961 return -ENXIO;
962 }
963
964 port = vcc_get_ne(tty->index);
965 if (unlikely(!port)) {
966 pr_err("VCC: break_ctl: Failed to find VCC port\n");
967 return -ENODEV;
968 }
969
970 /* Turn off break */
971 if (state == 0) {
972 vcc_put(port, false);
973 return 0;
974 }
975
976 spin_lock_irqsave(&port->lock, flags);
977
978 if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
979 vcc_kick_tx(port);
980
981 spin_unlock_irqrestore(&port->lock, flags);
982
983 vcc_put(port, false);
984
985 return 0;
986}
987
988static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
989{
990 struct vcc_port *port_vcc;
991 struct tty_port *port_tty;
992 int ret;
993
994 if (unlikely(!tty)) {
995 pr_err("VCC: install: Invalid TTY handle\n");
996 return -ENXIO;
997 }
998
999 if (tty->index >= VCC_MAX_PORTS)
1000 return -EINVAL;
1001
1002 ret = tty_standard_install(driver, tty);
1003 if (ret)
1004 return ret;
1005
1006 port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
1007 if (!port_tty)
1008 return -ENOMEM;
1009
1010 port_vcc = vcc_get(tty->index, true);
1011 if (!port_vcc) {
1012 pr_err("VCC: install: Failed to find VCC port\n");
1013 tty->port = NULL;
1014 kfree(port_tty);
1015 return -ENODEV;
1016 }
1017
1018 tty_port_init(port_tty);
1019 port_tty->ops = &vcc_port_ops;
1020 tty->port = port_tty;
1021
1022 port_vcc->tty = tty;
1023
1024 vcc_put(port_vcc, true);
1025
1026 return 0;
1027}
1028
1029static void vcc_cleanup(struct tty_struct *tty)
1030{
1031 struct vcc_port *port;
1032
1033 if (unlikely(!tty)) {
1034 pr_err("VCC: cleanup: Invalid TTY handle\n");
1035 return;
1036 }
1037
1038 port = vcc_get(tty->index, true);
1039 if (port) {
1040 port->tty = NULL;
1041
1042 if (port->removed) {
1043 vcc_table_remove(tty->index);
1044 kfree(port->vio.name);
1045 kfree(port->domain);
1046 kfree(port);
1047 } else {
1048 vcc_put(port, true);
1049 }
1050 }
1051
1052 tty_port_destroy(tty->port);
1053 kfree(tty->port);
1054 tty->port = NULL;
1055}
1056
1057static const struct tty_operations vcc_ops = {
1058 .open = vcc_open,
1059 .close = vcc_close,
1060 .hangup = vcc_hangup,
1061 .write = vcc_write,
1062 .write_room = vcc_write_room,
1063 .chars_in_buffer = vcc_chars_in_buffer,
1064 .break_ctl = vcc_break_ctl,
1065 .install = vcc_install,
1066 .cleanup = vcc_cleanup,
1067};
1068
1069#define VCC_TTY_FLAGS (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1070
1071static int vcc_tty_init(void)
1072{
1073 int rv;
1074
1075 pr_info("VCC: %s\n", version);
1076
1077 vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1078 if (IS_ERR(vcc_tty_driver)) {
1079 pr_err("VCC: TTY driver alloc failed\n");
1080 return PTR_ERR(vcc_tty_driver);
1081 }
1082
1083 vcc_tty_driver->driver_name = vcc_driver_name;
1084 vcc_tty_driver->name = vcc_device_node;
1085
1086 vcc_tty_driver->minor_start = VCC_MINOR_START;
1087 vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1088 vcc_tty_driver->init_termios = vcc_tty_termios;
1089
1090 tty_set_operations(vcc_tty_driver, &vcc_ops);
1091
1092 rv = tty_register_driver(vcc_tty_driver);
1093 if (rv) {
1094 pr_err("VCC: TTY driver registration failed\n");
1095 put_tty_driver(vcc_tty_driver);
1096 vcc_tty_driver = NULL;
1097 return rv;
1098 }
1099
1100 vccdbg("VCC: TTY driver registered\n");
1101
1102 return 0;
1103}
1104
1105static void vcc_tty_exit(void)
1106{
1107 tty_unregister_driver(vcc_tty_driver);
1108 put_tty_driver(vcc_tty_driver);
1109 vccdbg("VCC: TTY driver unregistered\n");
1110
1111 vcc_tty_driver = NULL;
1112}
1113
1114static int __init vcc_init(void)
1115{
1116 int rv;
1117
1118 rv = vcc_tty_init();
1119 if (rv) {
1120 pr_err("VCC: TTY init failed\n");
1121 return rv;
1122 }
1123
1124 rv = vio_register_driver(&vcc_driver);
1125 if (rv) {
1126 pr_err("VCC: VIO driver registration failed\n");
1127 vcc_tty_exit();
1128 } else {
1129 vccdbg("VCC: VIO driver registered successfully\n");
1130 }
1131
1132 return rv;
1133}
1134
1135static void __exit vcc_exit(void)
1136{
1137 vio_unregister_driver(&vcc_driver);
1138 vccdbg("VCC: VIO driver unregistered\n");
1139 vcc_tty_exit();
1140 vccdbg("VCC: TTY driver unregistered\n");
1141}
1142
1143module_init(vcc_init);
1144module_exit(vcc_exit);
1// SPDX-License-Identifier: GPL-2.0
2/* vcc.c: sun4v virtual channel concentrator
3 *
4 * Copyright (C) 2017 Oracle. All rights reserved.
5 */
6
7#include <linux/delay.h>
8#include <linux/interrupt.h>
9#include <linux/module.h>
10#include <linux/slab.h>
11#include <linux/sysfs.h>
12#include <linux/tty.h>
13#include <linux/tty_flip.h>
14#include <asm/vio.h>
15#include <asm/ldc.h>
16
17MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
18MODULE_LICENSE("GPL");
19MODULE_VERSION("1.1");
20
21struct vcc_port {
22 struct vio_driver_state vio;
23
24 spinlock_t lock;
25 char *domain;
26 struct tty_struct *tty; /* only populated while dev is open */
27 unsigned long index; /* index into the vcc_table */
28
29 u64 refcnt;
30 bool excl_locked;
31
32 bool removed;
33
34 /* This buffer is required to support the tty write_room interface
35 * and guarantee that any characters that the driver accepts will
36 * be eventually sent, either immediately or later.
37 */
38 int chars_in_buffer;
39 struct vio_vcc buffer;
40
41 struct timer_list rx_timer;
42 struct timer_list tx_timer;
43};
44
45/* Microseconds that thread will delay waiting for a vcc port ref */
46#define VCC_REF_DELAY 100
47
48#define VCC_MAX_PORTS 1024
49#define VCC_MINOR_START 0 /* must be zero */
50#define VCC_BUFF_LEN VIO_VCC_MTU_SIZE
51
52#define VCC_CTL_BREAK -1
53#define VCC_CTL_HUP -2
54
55static struct tty_driver *vcc_tty_driver;
56
57static struct vcc_port *vcc_table[VCC_MAX_PORTS];
58static DEFINE_SPINLOCK(vcc_table_lock);
59
60static unsigned int vcc_dbg;
61static unsigned int vcc_dbg_ldc;
62static unsigned int vcc_dbg_vio;
63
64module_param(vcc_dbg, uint, 0664);
65module_param(vcc_dbg_ldc, uint, 0664);
66module_param(vcc_dbg_vio, uint, 0664);
67
68#define VCC_DBG_DRV 0x1
69#define VCC_DBG_LDC 0x2
70#define VCC_DBG_PKT 0x4
71
72#define vccdbg(f, a...) \
73 do { \
74 if (vcc_dbg & VCC_DBG_DRV) \
75 pr_info(f, ## a); \
76 } while (0) \
77
78#define vccdbgl(l) \
79 do { \
80 if (vcc_dbg & VCC_DBG_LDC) \
81 ldc_print(l); \
82 } while (0) \
83
84#define vccdbgp(pkt) \
85 do { \
86 if (vcc_dbg & VCC_DBG_PKT) { \
87 int i; \
88 for (i = 0; i < pkt.tag.stype; i++) \
89 pr_info("[%c]", pkt.data[i]); \
90 } \
91 } while (0) \
92
93/* Note: Be careful when adding flags to this line discipline. Don't
94 * add anything that will cause echoing or we'll go into recursive
95 * loop echoing chars back and forth with the console drivers.
96 */
97static const struct ktermios vcc_tty_termios = {
98 .c_iflag = IGNBRK | IGNPAR,
99 .c_oflag = OPOST,
100 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
101 .c_cc = INIT_C_CC,
102 .c_ispeed = 38400,
103 .c_ospeed = 38400
104};
105
106/**
107 * vcc_table_add() - Add VCC port to the VCC table
108 * @port: pointer to the VCC port
109 *
110 * Return: index of the port in the VCC table on success,
111 * -1 on failure
112 */
113static int vcc_table_add(struct vcc_port *port)
114{
115 unsigned long flags;
116 int i;
117
118 spin_lock_irqsave(&vcc_table_lock, flags);
119 for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
120 if (!vcc_table[i]) {
121 vcc_table[i] = port;
122 break;
123 }
124 }
125 spin_unlock_irqrestore(&vcc_table_lock, flags);
126
127 if (i < VCC_MAX_PORTS)
128 return i;
129 else
130 return -1;
131}
132
133/**
134 * vcc_table_remove() - Removes a VCC port from the VCC table
135 * @index: Index into the VCC table
136 */
137static void vcc_table_remove(unsigned long index)
138{
139 unsigned long flags;
140
141 if (WARN_ON(index >= VCC_MAX_PORTS))
142 return;
143
144 spin_lock_irqsave(&vcc_table_lock, flags);
145 vcc_table[index] = NULL;
146 spin_unlock_irqrestore(&vcc_table_lock, flags);
147}
148
149/**
150 * vcc_get() - Gets a reference to VCC port
151 * @index: Index into the VCC table
152 * @excl: Indicates if an exclusive access is requested
153 *
154 * Return: reference to the VCC port, if found
155 * NULL, if port not found
156 */
157static struct vcc_port *vcc_get(unsigned long index, bool excl)
158{
159 struct vcc_port *port;
160 unsigned long flags;
161
162try_again:
163 spin_lock_irqsave(&vcc_table_lock, flags);
164
165 port = vcc_table[index];
166 if (!port) {
167 spin_unlock_irqrestore(&vcc_table_lock, flags);
168 return NULL;
169 }
170
171 if (!excl) {
172 if (port->excl_locked) {
173 spin_unlock_irqrestore(&vcc_table_lock, flags);
174 udelay(VCC_REF_DELAY);
175 goto try_again;
176 }
177 port->refcnt++;
178 spin_unlock_irqrestore(&vcc_table_lock, flags);
179 return port;
180 }
181
182 if (port->refcnt) {
183 spin_unlock_irqrestore(&vcc_table_lock, flags);
184 /* Threads wanting exclusive access will wait half the time,
185 * probably giving them higher priority in the case of
186 * multiple waiters.
187 */
188 udelay(VCC_REF_DELAY/2);
189 goto try_again;
190 }
191
192 port->refcnt++;
193 port->excl_locked = true;
194 spin_unlock_irqrestore(&vcc_table_lock, flags);
195
196 return port;
197}
198
199/**
200 * vcc_put() - Returns a reference to VCC port
201 * @port: pointer to VCC port
202 * @excl: Indicates if the returned reference is an exclusive reference
203 *
204 * Note: It's the caller's responsibility to ensure the correct value
205 * for the excl flag
206 */
207static void vcc_put(struct vcc_port *port, bool excl)
208{
209 unsigned long flags;
210
211 if (!port)
212 return;
213
214 spin_lock_irqsave(&vcc_table_lock, flags);
215
216 /* check if caller attempted to put with the wrong flags */
217 if (WARN_ON((excl && !port->excl_locked) ||
218 (!excl && port->excl_locked)))
219 goto done;
220
221 port->refcnt--;
222
223 if (excl)
224 port->excl_locked = false;
225
226done:
227 spin_unlock_irqrestore(&vcc_table_lock, flags);
228}
229
230/**
231 * vcc_get_ne() - Get a non-exclusive reference to VCC port
232 * @index: Index into the VCC table
233 *
234 * Gets a non-exclusive reference to VCC port, if it's not removed
235 *
236 * Return: pointer to the VCC port, if found
237 * NULL, if port not found
238 */
239static struct vcc_port *vcc_get_ne(unsigned long index)
240{
241 struct vcc_port *port;
242
243 port = vcc_get(index, false);
244
245 if (port && port->removed) {
246 vcc_put(port, false);
247 return NULL;
248 }
249
250 return port;
251}
252
253static void vcc_kick_rx(struct vcc_port *port)
254{
255 struct vio_driver_state *vio = &port->vio;
256
257 assert_spin_locked(&port->lock);
258
259 if (!timer_pending(&port->rx_timer) && !port->removed) {
260 disable_irq_nosync(vio->vdev->rx_irq);
261 port->rx_timer.expires = (jiffies + 1);
262 add_timer(&port->rx_timer);
263 }
264}
265
266static void vcc_kick_tx(struct vcc_port *port)
267{
268 assert_spin_locked(&port->lock);
269
270 if (!timer_pending(&port->tx_timer) && !port->removed) {
271 port->tx_timer.expires = (jiffies + 1);
272 add_timer(&port->tx_timer);
273 }
274}
275
276static int vcc_rx_check(struct tty_struct *tty, int size)
277{
278 if (WARN_ON(!tty || !tty->port))
279 return 1;
280
281 /* tty_buffer_request_room won't sleep because it uses
282 * GFP_ATOMIC flag to allocate buffer
283 */
284 if (test_bit(TTY_THROTTLED, &tty->flags) ||
285 (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
286 return 0;
287
288 return 1;
289}
290
291static int vcc_rx(struct tty_struct *tty, char *buf, int size)
292{
293 int len = 0;
294
295 if (WARN_ON(!tty || !tty->port))
296 return len;
297
298 len = tty_insert_flip_string(tty->port, buf, size);
299 if (len)
300 tty_flip_buffer_push(tty->port);
301
302 return len;
303}
304
305static int vcc_ldc_read(struct vcc_port *port)
306{
307 struct vio_driver_state *vio = &port->vio;
308 struct tty_struct *tty;
309 struct vio_vcc pkt;
310 int rv = 0;
311
312 tty = port->tty;
313 if (!tty) {
314 rv = ldc_rx_reset(vio->lp);
315 vccdbg("VCC: reset rx q: rv=%d\n", rv);
316 goto done;
317 }
318
319 /* Read as long as LDC has incoming data. */
320 while (1) {
321 if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
322 vcc_kick_rx(port);
323 break;
324 }
325
326 vccdbgl(vio->lp);
327
328 rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
329 if (rv <= 0)
330 break;
331
332 vccdbg("VCC: ldc_read()=%d\n", rv);
333 vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
334 pkt.tag.type, pkt.tag.stype,
335 pkt.tag.stype_env, pkt.tag.sid);
336
337 if (pkt.tag.type == VIO_TYPE_DATA) {
338 vccdbgp(pkt);
339 /* vcc_rx_check ensures memory availability */
340 vcc_rx(tty, pkt.data, pkt.tag.stype);
341 } else {
342 pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
343 pkt.tag.type, pkt.tag.stype,
344 pkt.tag.stype_env, pkt.tag.sid);
345 rv = -ECONNRESET;
346 break;
347 }
348
349 WARN_ON(rv != LDC_PACKET_SIZE);
350 }
351
352done:
353 return rv;
354}
355
356static void vcc_rx_timer(struct timer_list *t)
357{
358 struct vcc_port *port = from_timer(port, t, rx_timer);
359 struct vio_driver_state *vio;
360 unsigned long flags;
361 int rv;
362
363 spin_lock_irqsave(&port->lock, flags);
364 port->rx_timer.expires = 0;
365
366 vio = &port->vio;
367
368 enable_irq(vio->vdev->rx_irq);
369
370 if (!port->tty || port->removed)
371 goto done;
372
373 rv = vcc_ldc_read(port);
374 if (rv == -ECONNRESET)
375 vio_conn_reset(vio);
376
377done:
378 spin_unlock_irqrestore(&port->lock, flags);
379 vcc_put(port, false);
380}
381
382static void vcc_tx_timer(struct timer_list *t)
383{
384 struct vcc_port *port = from_timer(port, t, tx_timer);
385 struct vio_vcc *pkt;
386 unsigned long flags;
387 int tosend = 0;
388 int rv;
389
390 spin_lock_irqsave(&port->lock, flags);
391 port->tx_timer.expires = 0;
392
393 if (!port->tty || port->removed)
394 goto done;
395
396 tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
397 if (!tosend)
398 goto done;
399
400 pkt = &port->buffer;
401 pkt->tag.type = VIO_TYPE_DATA;
402 pkt->tag.stype = tosend;
403 vccdbgl(port->vio.lp);
404
405 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
406 WARN_ON(!rv);
407
408 if (rv < 0) {
409 vccdbg("VCC: ldc_write()=%d\n", rv);
410 vcc_kick_tx(port);
411 } else {
412 struct tty_struct *tty = port->tty;
413
414 port->chars_in_buffer = 0;
415 if (tty)
416 tty_wakeup(tty);
417 }
418
419done:
420 spin_unlock_irqrestore(&port->lock, flags);
421 vcc_put(port, false);
422}
423
424/**
425 * vcc_event() - LDC event processing engine
426 * @arg: VCC private data
427 * @event: LDC event
428 *
429 * Handles LDC events for VCC
430 */
431static void vcc_event(void *arg, int event)
432{
433 struct vio_driver_state *vio;
434 struct vcc_port *port;
435 unsigned long flags;
436 int rv;
437
438 port = arg;
439 vio = &port->vio;
440
441 spin_lock_irqsave(&port->lock, flags);
442
443 switch (event) {
444 case LDC_EVENT_RESET:
445 case LDC_EVENT_UP:
446 vio_link_state_change(vio, event);
447 break;
448
449 case LDC_EVENT_DATA_READY:
450 rv = vcc_ldc_read(port);
451 if (rv == -ECONNRESET)
452 vio_conn_reset(vio);
453 break;
454
455 default:
456 pr_err("VCC: unexpected LDC event(%d)\n", event);
457 }
458
459 spin_unlock_irqrestore(&port->lock, flags);
460}
461
462static struct ldc_channel_config vcc_ldc_cfg = {
463 .event = vcc_event,
464 .mtu = VIO_VCC_MTU_SIZE,
465 .mode = LDC_MODE_RAW,
466 .debug = 0,
467};
468
469/* Ordered from largest major to lowest */
470static struct vio_version vcc_versions[] = {
471 { .major = 1, .minor = 0 },
472};
473
474static struct tty_port_operations vcc_port_ops = { 0 };
475
476static ssize_t domain_show(struct device *dev,
477 struct device_attribute *attr,
478 char *buf)
479{
480 struct vcc_port *port;
481 int rv;
482
483 port = dev_get_drvdata(dev);
484 if (!port)
485 return -ENODEV;
486
487 rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
488
489 return rv;
490}
491
492static int vcc_send_ctl(struct vcc_port *port, int ctl)
493{
494 struct vio_vcc pkt;
495 int rv;
496
497 pkt.tag.type = VIO_TYPE_CTRL;
498 pkt.tag.sid = ctl;
499 pkt.tag.stype = 0;
500
501 rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
502 WARN_ON(!rv);
503 vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
504
505 return rv;
506}
507
508static ssize_t break_store(struct device *dev,
509 struct device_attribute *attr,
510 const char *buf, size_t count)
511{
512 struct vcc_port *port;
513 unsigned long flags;
514 int rv = count;
515 int brk;
516
517 port = dev_get_drvdata(dev);
518 if (!port)
519 return -ENODEV;
520
521 spin_lock_irqsave(&port->lock, flags);
522
523 if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
524 rv = -EINVAL;
525 else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
526 vcc_kick_tx(port);
527
528 spin_unlock_irqrestore(&port->lock, flags);
529
530 return rv;
531}
532
533static DEVICE_ATTR_ADMIN_RO(domain);
534static DEVICE_ATTR_WO(break);
535
536static struct attribute *vcc_sysfs_entries[] = {
537 &dev_attr_domain.attr,
538 &dev_attr_break.attr,
539 NULL
540};
541
542static struct attribute_group vcc_attribute_group = {
543 .name = NULL,
544 .attrs = vcc_sysfs_entries,
545};
546
547/**
548 * vcc_probe() - Initialize VCC port
549 * @vdev: Pointer to VIO device of the new VCC port
550 * @id: VIO device ID
551 *
552 * Initializes a VCC port to receive serial console data from
553 * the guest domain. Sets up a TTY end point on the control
554 * domain. Sets up VIO/LDC link between the guest & control
555 * domain endpoints.
556 *
557 * Return: status of the probe
558 */
559static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
560{
561 struct mdesc_handle *hp;
562 struct vcc_port *port;
563 struct device *dev;
564 const char *domain;
565 char *name;
566 u64 node;
567 int rv;
568
569 vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
570
571 if (!vcc_tty_driver) {
572 pr_err("VCC: TTY driver not registered\n");
573 return -ENODEV;
574 }
575
576 port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
577 if (!port)
578 return -ENOMEM;
579
580 name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
581
582 rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
583 ARRAY_SIZE(vcc_versions), NULL, name);
584 if (rv)
585 goto free_port;
586
587 port->vio.debug = vcc_dbg_vio;
588 vcc_ldc_cfg.debug = vcc_dbg_ldc;
589
590 rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
591 if (rv)
592 goto free_port;
593
594 spin_lock_init(&port->lock);
595
596 port->index = vcc_table_add(port);
597 if (port->index == -1) {
598 pr_err("VCC: no more TTY indices left for allocation\n");
599 rv = -ENOMEM;
600 goto free_ldc;
601 }
602
603 /* Register the device using VCC table index as TTY index */
604 dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
605 if (IS_ERR(dev)) {
606 rv = PTR_ERR(dev);
607 goto free_table;
608 }
609
610 hp = mdesc_grab();
611
612 node = vio_vdev_node(hp, vdev);
613 if (node == MDESC_NODE_NULL) {
614 rv = -ENXIO;
615 mdesc_release(hp);
616 goto unreg_tty;
617 }
618
619 domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
620 if (!domain) {
621 rv = -ENXIO;
622 mdesc_release(hp);
623 goto unreg_tty;
624 }
625 port->domain = kstrdup(domain, GFP_KERNEL);
626
627 mdesc_release(hp);
628
629 rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
630 if (rv)
631 goto free_domain;
632
633 timer_setup(&port->rx_timer, vcc_rx_timer, 0);
634 timer_setup(&port->tx_timer, vcc_tx_timer, 0);
635
636 dev_set_drvdata(&vdev->dev, port);
637
638 /* It's possible to receive IRQs in the middle of vio_port_up. Disable
639 * IRQs until the port is up.
640 */
641 disable_irq_nosync(vdev->rx_irq);
642 vio_port_up(&port->vio);
643 enable_irq(vdev->rx_irq);
644
645 return 0;
646
647free_domain:
648 kfree(port->domain);
649unreg_tty:
650 tty_unregister_device(vcc_tty_driver, port->index);
651free_table:
652 vcc_table_remove(port->index);
653free_ldc:
654 vio_ldc_free(&port->vio);
655free_port:
656 kfree(name);
657 kfree(port);
658
659 return rv;
660}
661
662/**
663 * vcc_remove() - Terminate a VCC port
664 * @vdev: Pointer to VIO device of the VCC port
665 *
666 * Terminates a VCC port. Sets up the teardown of TTY and
667 * VIO/LDC link between guest and primary domains.
668 *
669 * Return: status of removal
670 */
671static void vcc_remove(struct vio_dev *vdev)
672{
673 struct vcc_port *port = dev_get_drvdata(&vdev->dev);
674
675 del_timer_sync(&port->rx_timer);
676 del_timer_sync(&port->tx_timer);
677
678 /* If there's a process with the device open, do a synchronous
679 * hangup of the TTY. This *may* cause the process to call close
680 * asynchronously, but it's not guaranteed.
681 */
682 if (port->tty)
683 tty_vhangup(port->tty);
684
685 /* Get exclusive reference to VCC, ensures that there are no other
686 * clients to this port. This cannot fail.
687 */
688 vcc_get(port->index, true);
689
690 tty_unregister_device(vcc_tty_driver, port->index);
691
692 del_timer_sync(&port->vio.timer);
693 vio_ldc_free(&port->vio);
694 sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
695 dev_set_drvdata(&vdev->dev, NULL);
696 if (port->tty) {
697 port->removed = true;
698 vcc_put(port, true);
699 } else {
700 vcc_table_remove(port->index);
701
702 kfree(port->vio.name);
703 kfree(port->domain);
704 kfree(port);
705 }
706}
707
708static const struct vio_device_id vcc_match[] = {
709 {
710 .type = "vcc-port",
711 },
712 {},
713};
714MODULE_DEVICE_TABLE(vio, vcc_match);
715
716static struct vio_driver vcc_driver = {
717 .id_table = vcc_match,
718 .probe = vcc_probe,
719 .remove = vcc_remove,
720 .name = "vcc",
721};
722
723static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
724{
725 struct vcc_port *port;
726
727 if (tty->count > 1)
728 return -EBUSY;
729
730 port = vcc_get_ne(tty->index);
731 if (unlikely(!port)) {
732 pr_err("VCC: open: Failed to find VCC port\n");
733 return -ENODEV;
734 }
735
736 if (unlikely(!port->vio.lp)) {
737 pr_err("VCC: open: LDC channel not configured\n");
738 vcc_put(port, false);
739 return -EPIPE;
740 }
741 vccdbgl(port->vio.lp);
742
743 vcc_put(port, false);
744
745 if (unlikely(!tty->port)) {
746 pr_err("VCC: open: TTY port not found\n");
747 return -ENXIO;
748 }
749
750 if (unlikely(!tty->port->ops)) {
751 pr_err("VCC: open: TTY ops not defined\n");
752 return -ENXIO;
753 }
754
755 return tty_port_open(tty->port, tty, vcc_file);
756}
757
758static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
759{
760 if (unlikely(tty->count > 1))
761 return;
762
763 if (unlikely(!tty->port)) {
764 pr_err("VCC: close: TTY port not found\n");
765 return;
766 }
767
768 tty_port_close(tty->port, tty, vcc_file);
769}
770
771static void vcc_ldc_hup(struct vcc_port *port)
772{
773 unsigned long flags;
774
775 spin_lock_irqsave(&port->lock, flags);
776
777 if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
778 vcc_kick_tx(port);
779
780 spin_unlock_irqrestore(&port->lock, flags);
781}
782
783static void vcc_hangup(struct tty_struct *tty)
784{
785 struct vcc_port *port;
786
787 port = vcc_get_ne(tty->index);
788 if (unlikely(!port)) {
789 pr_err("VCC: hangup: Failed to find VCC port\n");
790 return;
791 }
792
793 if (unlikely(!tty->port)) {
794 pr_err("VCC: hangup: TTY port not found\n");
795 vcc_put(port, false);
796 return;
797 }
798
799 vcc_ldc_hup(port);
800
801 vcc_put(port, false);
802
803 tty_port_hangup(tty->port);
804}
805
806static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
807 int count)
808{
809 struct vcc_port *port;
810 struct vio_vcc *pkt;
811 unsigned long flags;
812 int total_sent = 0;
813 int tosend = 0;
814 int rv = -EINVAL;
815
816 port = vcc_get_ne(tty->index);
817 if (unlikely(!port)) {
818 pr_err("VCC: write: Failed to find VCC port");
819 return -ENODEV;
820 }
821
822 spin_lock_irqsave(&port->lock, flags);
823
824 pkt = &port->buffer;
825 pkt->tag.type = VIO_TYPE_DATA;
826
827 while (count > 0) {
828 /* Minimum of data to write and space available */
829 tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
830
831 if (!tosend)
832 break;
833
834 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
835 tosend);
836 port->chars_in_buffer += tosend;
837 pkt->tag.stype = tosend;
838
839 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
840 pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
841 vccdbg("DATA [%s]\n", pkt->data);
842 vccdbgl(port->vio.lp);
843
844 /* Since we know we have enough room in VCC buffer for tosend
845 * we record that it was sent regardless of whether the
846 * hypervisor actually took it because we have it buffered.
847 */
848 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
849 vccdbg("VCC: write: ldc_write(%d)=%d\n",
850 (VIO_TAG_SIZE + tosend), rv);
851
852 total_sent += tosend;
853 count -= tosend;
854 if (rv < 0) {
855 vcc_kick_tx(port);
856 break;
857 }
858
859 port->chars_in_buffer = 0;
860 }
861
862 spin_unlock_irqrestore(&port->lock, flags);
863
864 vcc_put(port, false);
865
866 vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
867
868 return total_sent ? total_sent : rv;
869}
870
871static unsigned int vcc_write_room(struct tty_struct *tty)
872{
873 struct vcc_port *port;
874 unsigned int num;
875
876 port = vcc_get_ne(tty->index);
877 if (unlikely(!port)) {
878 pr_err("VCC: write_room: Failed to find VCC port\n");
879 return 0;
880 }
881
882 num = VCC_BUFF_LEN - port->chars_in_buffer;
883
884 vcc_put(port, false);
885
886 return num;
887}
888
889static unsigned int vcc_chars_in_buffer(struct tty_struct *tty)
890{
891 struct vcc_port *port;
892 unsigned int num;
893
894 port = vcc_get_ne(tty->index);
895 if (unlikely(!port)) {
896 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
897 return 0;
898 }
899
900 num = port->chars_in_buffer;
901
902 vcc_put(port, false);
903
904 return num;
905}
906
907static int vcc_break_ctl(struct tty_struct *tty, int state)
908{
909 struct vcc_port *port;
910 unsigned long flags;
911
912 port = vcc_get_ne(tty->index);
913 if (unlikely(!port)) {
914 pr_err("VCC: break_ctl: Failed to find VCC port\n");
915 return -ENODEV;
916 }
917
918 /* Turn off break */
919 if (state == 0) {
920 vcc_put(port, false);
921 return 0;
922 }
923
924 spin_lock_irqsave(&port->lock, flags);
925
926 if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
927 vcc_kick_tx(port);
928
929 spin_unlock_irqrestore(&port->lock, flags);
930
931 vcc_put(port, false);
932
933 return 0;
934}
935
936static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
937{
938 struct vcc_port *port_vcc;
939 struct tty_port *port_tty;
940 int ret;
941
942 if (tty->index >= VCC_MAX_PORTS)
943 return -EINVAL;
944
945 ret = tty_standard_install(driver, tty);
946 if (ret)
947 return ret;
948
949 port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
950 if (!port_tty)
951 return -ENOMEM;
952
953 port_vcc = vcc_get(tty->index, true);
954 if (!port_vcc) {
955 pr_err("VCC: install: Failed to find VCC port\n");
956 tty->port = NULL;
957 kfree(port_tty);
958 return -ENODEV;
959 }
960
961 tty_port_init(port_tty);
962 port_tty->ops = &vcc_port_ops;
963 tty->port = port_tty;
964
965 port_vcc->tty = tty;
966
967 vcc_put(port_vcc, true);
968
969 return 0;
970}
971
972static void vcc_cleanup(struct tty_struct *tty)
973{
974 struct vcc_port *port;
975
976 port = vcc_get(tty->index, true);
977 if (port) {
978 port->tty = NULL;
979
980 if (port->removed) {
981 vcc_table_remove(tty->index);
982 kfree(port->vio.name);
983 kfree(port->domain);
984 kfree(port);
985 } else {
986 vcc_put(port, true);
987 }
988 }
989
990 tty_port_destroy(tty->port);
991 kfree(tty->port);
992 tty->port = NULL;
993}
994
995static const struct tty_operations vcc_ops = {
996 .open = vcc_open,
997 .close = vcc_close,
998 .hangup = vcc_hangup,
999 .write = vcc_write,
1000 .write_room = vcc_write_room,
1001 .chars_in_buffer = vcc_chars_in_buffer,
1002 .break_ctl = vcc_break_ctl,
1003 .install = vcc_install,
1004 .cleanup = vcc_cleanup,
1005};
1006
1007#define VCC_TTY_FLAGS (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1008
1009static int vcc_tty_init(void)
1010{
1011 int rv;
1012
1013 vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1014 if (IS_ERR(vcc_tty_driver)) {
1015 pr_err("VCC: TTY driver alloc failed\n");
1016 return PTR_ERR(vcc_tty_driver);
1017 }
1018
1019 vcc_tty_driver->driver_name = "vcc";
1020 vcc_tty_driver->name = "vcc";
1021
1022 vcc_tty_driver->minor_start = VCC_MINOR_START;
1023 vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1024 vcc_tty_driver->init_termios = vcc_tty_termios;
1025
1026 tty_set_operations(vcc_tty_driver, &vcc_ops);
1027
1028 rv = tty_register_driver(vcc_tty_driver);
1029 if (rv) {
1030 pr_err("VCC: TTY driver registration failed\n");
1031 put_tty_driver(vcc_tty_driver);
1032 vcc_tty_driver = NULL;
1033 return rv;
1034 }
1035
1036 vccdbg("VCC: TTY driver registered\n");
1037
1038 return 0;
1039}
1040
1041static void vcc_tty_exit(void)
1042{
1043 tty_unregister_driver(vcc_tty_driver);
1044 put_tty_driver(vcc_tty_driver);
1045 vccdbg("VCC: TTY driver unregistered\n");
1046
1047 vcc_tty_driver = NULL;
1048}
1049
1050static int __init vcc_init(void)
1051{
1052 int rv;
1053
1054 rv = vcc_tty_init();
1055 if (rv) {
1056 pr_err("VCC: TTY init failed\n");
1057 return rv;
1058 }
1059
1060 rv = vio_register_driver(&vcc_driver);
1061 if (rv) {
1062 pr_err("VCC: VIO driver registration failed\n");
1063 vcc_tty_exit();
1064 } else {
1065 vccdbg("VCC: VIO driver registered successfully\n");
1066 }
1067
1068 return rv;
1069}
1070
1071static void __exit vcc_exit(void)
1072{
1073 vio_unregister_driver(&vcc_driver);
1074 vccdbg("VCC: VIO driver unregistered\n");
1075 vcc_tty_exit();
1076 vccdbg("VCC: TTY driver unregistered\n");
1077}
1078
1079module_init(vcc_init);
1080module_exit(vcc_exit);