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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 <linux/termios_internal.h>
15#include <asm/vio.h>
16#include <asm/ldc.h>
17
18MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
19MODULE_LICENSE("GPL");
20MODULE_VERSION("1.1");
21
22struct vcc_port {
23 struct vio_driver_state vio;
24
25 spinlock_t lock;
26 char *domain;
27 struct tty_struct *tty; /* only populated while dev is open */
28 unsigned long index; /* index into the vcc_table */
29
30 u64 refcnt;
31 bool excl_locked;
32
33 bool removed;
34
35 /* This buffer is required to support the tty write_room interface
36 * and guarantee that any characters that the driver accepts will
37 * be eventually sent, either immediately or later.
38 */
39 size_t chars_in_buffer;
40 struct vio_vcc buffer;
41
42 struct timer_list rx_timer;
43 struct timer_list tx_timer;
44};
45
46/* Microseconds that thread will delay waiting for a vcc port ref */
47#define VCC_REF_DELAY 100
48
49#define VCC_MAX_PORTS 1024
50#define VCC_MINOR_START 0 /* must be zero */
51#define VCC_BUFF_LEN VIO_VCC_MTU_SIZE
52
53#define VCC_CTL_BREAK -1
54#define VCC_CTL_HUP -2
55
56static struct tty_driver *vcc_tty_driver;
57
58static struct vcc_port *vcc_table[VCC_MAX_PORTS];
59static DEFINE_SPINLOCK(vcc_table_lock);
60
61static unsigned int vcc_dbg;
62static unsigned int vcc_dbg_ldc;
63static unsigned int vcc_dbg_vio;
64
65module_param(vcc_dbg, uint, 0664);
66module_param(vcc_dbg_ldc, uint, 0664);
67module_param(vcc_dbg_vio, uint, 0664);
68
69#define VCC_DBG_DRV 0x1
70#define VCC_DBG_LDC 0x2
71#define VCC_DBG_PKT 0x4
72
73#define vccdbg(f, a...) \
74 do { \
75 if (vcc_dbg & VCC_DBG_DRV) \
76 pr_info(f, ## a); \
77 } while (0) \
78
79#define vccdbgl(l) \
80 do { \
81 if (vcc_dbg & VCC_DBG_LDC) \
82 ldc_print(l); \
83 } while (0) \
84
85#define vccdbgp(pkt) \
86 do { \
87 if (vcc_dbg & VCC_DBG_PKT) { \
88 int i; \
89 for (i = 0; i < pkt.tag.stype; i++) \
90 pr_info("[%c]", pkt.data[i]); \
91 } \
92 } while (0) \
93
94/* Note: Be careful when adding flags to this line discipline. Don't
95 * add anything that will cause echoing or we'll go into recursive
96 * loop echoing chars back and forth with the console drivers.
97 */
98static const struct ktermios vcc_tty_termios = {
99 .c_iflag = IGNBRK | IGNPAR,
100 .c_oflag = OPOST,
101 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
102 .c_cc = INIT_C_CC,
103 .c_ispeed = 38400,
104 .c_ospeed = 38400
105};
106
107/**
108 * vcc_table_add() - Add VCC port to the VCC table
109 * @port: pointer to the VCC port
110 *
111 * Return: index of the port in the VCC table on success,
112 * -1 on failure
113 */
114static int vcc_table_add(struct vcc_port *port)
115{
116 unsigned long flags;
117 int i;
118
119 spin_lock_irqsave(&vcc_table_lock, flags);
120 for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
121 if (!vcc_table[i]) {
122 vcc_table[i] = port;
123 break;
124 }
125 }
126 spin_unlock_irqrestore(&vcc_table_lock, flags);
127
128 if (i < VCC_MAX_PORTS)
129 return i;
130 else
131 return -1;
132}
133
134/**
135 * vcc_table_remove() - Removes a VCC port from the VCC table
136 * @index: Index into the VCC table
137 */
138static void vcc_table_remove(unsigned long index)
139{
140 unsigned long flags;
141
142 if (WARN_ON(index >= VCC_MAX_PORTS))
143 return;
144
145 spin_lock_irqsave(&vcc_table_lock, flags);
146 vcc_table[index] = NULL;
147 spin_unlock_irqrestore(&vcc_table_lock, flags);
148}
149
150/**
151 * vcc_get() - Gets a reference to VCC port
152 * @index: Index into the VCC table
153 * @excl: Indicates if an exclusive access is requested
154 *
155 * Return: reference to the VCC port, if found
156 * NULL, if port not found
157 */
158static struct vcc_port *vcc_get(unsigned long index, bool excl)
159{
160 struct vcc_port *port;
161 unsigned long flags;
162
163try_again:
164 spin_lock_irqsave(&vcc_table_lock, flags);
165
166 port = vcc_table[index];
167 if (!port) {
168 spin_unlock_irqrestore(&vcc_table_lock, flags);
169 return NULL;
170 }
171
172 if (!excl) {
173 if (port->excl_locked) {
174 spin_unlock_irqrestore(&vcc_table_lock, flags);
175 udelay(VCC_REF_DELAY);
176 goto try_again;
177 }
178 port->refcnt++;
179 spin_unlock_irqrestore(&vcc_table_lock, flags);
180 return port;
181 }
182
183 if (port->refcnt) {
184 spin_unlock_irqrestore(&vcc_table_lock, flags);
185 /* Threads wanting exclusive access will wait half the time,
186 * probably giving them higher priority in the case of
187 * multiple waiters.
188 */
189 udelay(VCC_REF_DELAY/2);
190 goto try_again;
191 }
192
193 port->refcnt++;
194 port->excl_locked = true;
195 spin_unlock_irqrestore(&vcc_table_lock, flags);
196
197 return port;
198}
199
200/**
201 * vcc_put() - Returns a reference to VCC port
202 * @port: pointer to VCC port
203 * @excl: Indicates if the returned reference is an exclusive reference
204 *
205 * Note: It's the caller's responsibility to ensure the correct value
206 * for the excl flag
207 */
208static void vcc_put(struct vcc_port *port, bool excl)
209{
210 unsigned long flags;
211
212 if (!port)
213 return;
214
215 spin_lock_irqsave(&vcc_table_lock, flags);
216
217 /* check if caller attempted to put with the wrong flags */
218 if (WARN_ON((excl && !port->excl_locked) ||
219 (!excl && port->excl_locked)))
220 goto done;
221
222 port->refcnt--;
223
224 if (excl)
225 port->excl_locked = false;
226
227done:
228 spin_unlock_irqrestore(&vcc_table_lock, flags);
229}
230
231/**
232 * vcc_get_ne() - Get a non-exclusive reference to VCC port
233 * @index: Index into the VCC table
234 *
235 * Gets a non-exclusive reference to VCC port, if it's not removed
236 *
237 * Return: pointer to the VCC port, if found
238 * NULL, if port not found
239 */
240static struct vcc_port *vcc_get_ne(unsigned long index)
241{
242 struct vcc_port *port;
243
244 port = vcc_get(index, false);
245
246 if (port && port->removed) {
247 vcc_put(port, false);
248 return NULL;
249 }
250
251 return port;
252}
253
254static void vcc_kick_rx(struct vcc_port *port)
255{
256 struct vio_driver_state *vio = &port->vio;
257
258 assert_spin_locked(&port->lock);
259
260 if (!timer_pending(&port->rx_timer) && !port->removed) {
261 disable_irq_nosync(vio->vdev->rx_irq);
262 port->rx_timer.expires = (jiffies + 1);
263 add_timer(&port->rx_timer);
264 }
265}
266
267static void vcc_kick_tx(struct vcc_port *port)
268{
269 assert_spin_locked(&port->lock);
270
271 if (!timer_pending(&port->tx_timer) && !port->removed) {
272 port->tx_timer.expires = (jiffies + 1);
273 add_timer(&port->tx_timer);
274 }
275}
276
277static int vcc_rx_check(struct tty_struct *tty, int size)
278{
279 if (WARN_ON(!tty || !tty->port))
280 return 1;
281
282 /* tty_buffer_request_room won't sleep because it uses
283 * GFP_ATOMIC flag to allocate buffer
284 */
285 if (test_bit(TTY_THROTTLED, &tty->flags) ||
286 (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
287 return 0;
288
289 return 1;
290}
291
292static int vcc_rx(struct tty_struct *tty, char *buf, int size)
293{
294 int len = 0;
295
296 if (WARN_ON(!tty || !tty->port))
297 return len;
298
299 len = tty_insert_flip_string(tty->port, buf, size);
300 if (len)
301 tty_flip_buffer_push(tty->port);
302
303 return len;
304}
305
306static int vcc_ldc_read(struct vcc_port *port)
307{
308 struct vio_driver_state *vio = &port->vio;
309 struct tty_struct *tty;
310 struct vio_vcc pkt;
311 int rv = 0;
312
313 tty = port->tty;
314 if (!tty) {
315 rv = ldc_rx_reset(vio->lp);
316 vccdbg("VCC: reset rx q: rv=%d\n", rv);
317 goto done;
318 }
319
320 /* Read as long as LDC has incoming data. */
321 while (1) {
322 if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
323 vcc_kick_rx(port);
324 break;
325 }
326
327 vccdbgl(vio->lp);
328
329 rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
330 if (rv <= 0)
331 break;
332
333 vccdbg("VCC: ldc_read()=%d\n", rv);
334 vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
335 pkt.tag.type, pkt.tag.stype,
336 pkt.tag.stype_env, pkt.tag.sid);
337
338 if (pkt.tag.type == VIO_TYPE_DATA) {
339 vccdbgp(pkt);
340 /* vcc_rx_check ensures memory availability */
341 vcc_rx(tty, pkt.data, pkt.tag.stype);
342 } else {
343 pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
344 pkt.tag.type, pkt.tag.stype,
345 pkt.tag.stype_env, pkt.tag.sid);
346 rv = -ECONNRESET;
347 break;
348 }
349
350 WARN_ON(rv != LDC_PACKET_SIZE);
351 }
352
353done:
354 return rv;
355}
356
357static void vcc_rx_timer(struct timer_list *t)
358{
359 struct vcc_port *port = timer_container_of(port, t, rx_timer);
360 struct vio_driver_state *vio;
361 unsigned long flags;
362 int rv;
363
364 spin_lock_irqsave(&port->lock, flags);
365 port->rx_timer.expires = 0;
366
367 vio = &port->vio;
368
369 enable_irq(vio->vdev->rx_irq);
370
371 if (!port->tty || port->removed)
372 goto done;
373
374 rv = vcc_ldc_read(port);
375 if (rv == -ECONNRESET)
376 vio_conn_reset(vio);
377
378done:
379 spin_unlock_irqrestore(&port->lock, flags);
380 vcc_put(port, false);
381}
382
383static void vcc_tx_timer(struct timer_list *t)
384{
385 struct vcc_port *port = timer_container_of(port, t, tx_timer);
386 struct vio_vcc *pkt;
387 unsigned long flags;
388 size_t tosend = 0;
389 int rv;
390
391 spin_lock_irqsave(&port->lock, flags);
392 port->tx_timer.expires = 0;
393
394 if (!port->tty || port->removed)
395 goto done;
396
397 tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
398 if (!tosend)
399 goto done;
400
401 pkt = &port->buffer;
402 pkt->tag.type = VIO_TYPE_DATA;
403 pkt->tag.stype = tosend;
404 vccdbgl(port->vio.lp);
405
406 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
407 WARN_ON(!rv);
408
409 if (rv < 0) {
410 vccdbg("VCC: ldc_write()=%d\n", rv);
411 vcc_kick_tx(port);
412 } else {
413 struct tty_struct *tty = port->tty;
414
415 port->chars_in_buffer = 0;
416 if (tty)
417 tty_wakeup(tty);
418 }
419
420done:
421 spin_unlock_irqrestore(&port->lock, flags);
422 vcc_put(port, false);
423}
424
425/**
426 * vcc_event() - LDC event processing engine
427 * @arg: VCC private data
428 * @event: LDC event
429 *
430 * Handles LDC events for VCC
431 */
432static void vcc_event(void *arg, int event)
433{
434 struct vio_driver_state *vio;
435 struct vcc_port *port;
436 unsigned long flags;
437 int rv;
438
439 port = arg;
440 vio = &port->vio;
441
442 spin_lock_irqsave(&port->lock, flags);
443
444 switch (event) {
445 case LDC_EVENT_RESET:
446 case LDC_EVENT_UP:
447 vio_link_state_change(vio, event);
448 break;
449
450 case LDC_EVENT_DATA_READY:
451 rv = vcc_ldc_read(port);
452 if (rv == -ECONNRESET)
453 vio_conn_reset(vio);
454 break;
455
456 default:
457 pr_err("VCC: unexpected LDC event(%d)\n", event);
458 }
459
460 spin_unlock_irqrestore(&port->lock, flags);
461}
462
463static struct ldc_channel_config vcc_ldc_cfg = {
464 .event = vcc_event,
465 .mtu = VIO_VCC_MTU_SIZE,
466 .mode = LDC_MODE_RAW,
467 .debug = 0,
468};
469
470/* Ordered from largest major to lowest */
471static struct vio_version vcc_versions[] = {
472 { .major = 1, .minor = 0 },
473};
474
475static struct tty_port_operations vcc_port_ops = { 0 };
476
477static ssize_t domain_show(struct device *dev,
478 struct device_attribute *attr,
479 char *buf)
480{
481 struct vcc_port *port;
482 int rv;
483
484 port = dev_get_drvdata(dev);
485 if (!port)
486 return -ENODEV;
487
488 rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
489
490 return rv;
491}
492
493static int vcc_send_ctl(struct vcc_port *port, int ctl)
494{
495 struct vio_vcc pkt = {};
496 int rv;
497
498 pkt.tag.type = VIO_TYPE_CTRL;
499 pkt.tag.sid = ctl;
500 pkt.tag.stype = 0;
501
502 rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
503 WARN_ON(!rv);
504 vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
505
506 return rv;
507}
508
509static ssize_t break_store(struct device *dev,
510 struct device_attribute *attr,
511 const char *buf, size_t count)
512{
513 struct vcc_port *port;
514 unsigned long flags;
515 int rv = count;
516 int brk;
517
518 port = dev_get_drvdata(dev);
519 if (!port)
520 return -ENODEV;
521
522 spin_lock_irqsave(&port->lock, flags);
523
524 if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
525 rv = -EINVAL;
526 else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
527 vcc_kick_tx(port);
528
529 spin_unlock_irqrestore(&port->lock, flags);
530
531 return rv;
532}
533
534static DEVICE_ATTR_ADMIN_RO(domain);
535static DEVICE_ATTR_WO(break);
536
537static struct attribute *vcc_sysfs_entries[] = {
538 &dev_attr_domain.attr,
539 &dev_attr_break.attr,
540 NULL
541};
542
543static struct attribute_group vcc_attribute_group = {
544 .name = NULL,
545 .attrs = vcc_sysfs_entries,
546};
547
548/**
549 * vcc_probe() - Initialize VCC port
550 * @vdev: Pointer to VIO device of the new VCC port
551 * @id: VIO device ID
552 *
553 * Initializes a VCC port to receive serial console data from
554 * the guest domain. Sets up a TTY end point on the control
555 * domain. Sets up VIO/LDC link between the guest & control
556 * domain endpoints.
557 *
558 * Return: status of the probe
559 */
560static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
561{
562 struct mdesc_handle *hp;
563 struct vcc_port *port;
564 struct device *dev;
565 const char *domain;
566 char *name;
567 u64 node;
568 int rv;
569
570 vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
571
572 if (!vcc_tty_driver) {
573 pr_err("VCC: TTY driver not registered\n");
574 return -ENODEV;
575 }
576
577 port = kzalloc_obj(struct vcc_port);
578 if (!port)
579 return -ENOMEM;
580
581 name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
582 if (!name) {
583 rv = -ENOMEM;
584 goto free_port;
585 }
586
587 rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
588 ARRAY_SIZE(vcc_versions), NULL, name);
589 if (rv)
590 goto free_name;
591
592 port->vio.debug = vcc_dbg_vio;
593 vcc_ldc_cfg.debug = vcc_dbg_ldc;
594
595 rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
596 if (rv)
597 goto free_name;
598
599 spin_lock_init(&port->lock);
600
601 port->index = vcc_table_add(port);
602 if (port->index == -1) {
603 pr_err("VCC: no more TTY indices left for allocation\n");
604 rv = -ENOMEM;
605 goto free_ldc;
606 }
607
608 /* Register the device using VCC table index as TTY index */
609 dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
610 if (IS_ERR(dev)) {
611 rv = PTR_ERR(dev);
612 goto free_table;
613 }
614
615 hp = mdesc_grab();
616
617 node = vio_vdev_node(hp, vdev);
618 if (node == MDESC_NODE_NULL) {
619 rv = -ENXIO;
620 mdesc_release(hp);
621 goto unreg_tty;
622 }
623
624 domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
625 if (!domain) {
626 rv = -ENXIO;
627 mdesc_release(hp);
628 goto unreg_tty;
629 }
630 port->domain = kstrdup(domain, GFP_KERNEL);
631 if (!port->domain) {
632 rv = -ENOMEM;
633 goto unreg_tty;
634 }
635
636
637 mdesc_release(hp);
638
639 rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
640 if (rv)
641 goto free_domain;
642
643 timer_setup(&port->rx_timer, vcc_rx_timer, 0);
644 timer_setup(&port->tx_timer, vcc_tx_timer, 0);
645
646 dev_set_drvdata(&vdev->dev, port);
647
648 /* It's possible to receive IRQs in the middle of vio_port_up. Disable
649 * IRQs until the port is up.
650 */
651 disable_irq_nosync(vdev->rx_irq);
652 vio_port_up(&port->vio);
653 enable_irq(vdev->rx_irq);
654
655 return 0;
656
657free_domain:
658 kfree(port->domain);
659unreg_tty:
660 tty_unregister_device(vcc_tty_driver, port->index);
661free_table:
662 vcc_table_remove(port->index);
663free_ldc:
664 vio_ldc_free(&port->vio);
665free_name:
666 kfree(name);
667free_port:
668 kfree(port);
669
670 return rv;
671}
672
673/**
674 * vcc_remove() - Terminate a VCC port
675 * @vdev: Pointer to VIO device of the VCC port
676 *
677 * Terminates a VCC port. Sets up the teardown of TTY and
678 * VIO/LDC link between guest and primary domains.
679 *
680 * Return: status of removal
681 */
682static void vcc_remove(struct vio_dev *vdev)
683{
684 struct vcc_port *port = dev_get_drvdata(&vdev->dev);
685
686 timer_delete_sync(&port->rx_timer);
687 timer_delete_sync(&port->tx_timer);
688
689 /* If there's a process with the device open, do a synchronous
690 * hangup of the TTY. This *may* cause the process to call close
691 * asynchronously, but it's not guaranteed.
692 */
693 if (port->tty)
694 tty_vhangup(port->tty);
695
696 /* Get exclusive reference to VCC, ensures that there are no other
697 * clients to this port. This cannot fail.
698 */
699 vcc_get(port->index, true);
700
701 tty_unregister_device(vcc_tty_driver, port->index);
702
703 timer_delete_sync(&port->vio.timer);
704 vio_ldc_free(&port->vio);
705 sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
706 dev_set_drvdata(&vdev->dev, NULL);
707 if (port->tty) {
708 port->removed = true;
709 vcc_put(port, true);
710 } else {
711 vcc_table_remove(port->index);
712
713 kfree(port->vio.name);
714 kfree(port->domain);
715 kfree(port);
716 }
717}
718
719static const struct vio_device_id vcc_match[] = {
720 {
721 .type = "vcc-port",
722 },
723 {},
724};
725MODULE_DEVICE_TABLE(vio, vcc_match);
726
727static struct vio_driver vcc_driver = {
728 .id_table = vcc_match,
729 .probe = vcc_probe,
730 .remove = vcc_remove,
731 .name = "vcc",
732};
733
734static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
735{
736 struct vcc_port *port;
737
738 if (tty->count > 1)
739 return -EBUSY;
740
741 port = vcc_get_ne(tty->index);
742 if (unlikely(!port)) {
743 pr_err("VCC: open: Failed to find VCC port\n");
744 return -ENODEV;
745 }
746
747 if (unlikely(!port->vio.lp)) {
748 pr_err("VCC: open: LDC channel not configured\n");
749 vcc_put(port, false);
750 return -EPIPE;
751 }
752 vccdbgl(port->vio.lp);
753
754 vcc_put(port, false);
755
756 if (unlikely(!tty->port)) {
757 pr_err("VCC: open: TTY port not found\n");
758 return -ENXIO;
759 }
760
761 if (unlikely(!tty->port->ops)) {
762 pr_err("VCC: open: TTY ops not defined\n");
763 return -ENXIO;
764 }
765
766 return tty_port_open(tty->port, tty, vcc_file);
767}
768
769static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
770{
771 if (unlikely(tty->count > 1))
772 return;
773
774 if (unlikely(!tty->port)) {
775 pr_err("VCC: close: TTY port not found\n");
776 return;
777 }
778
779 tty_port_close(tty->port, tty, vcc_file);
780}
781
782static void vcc_ldc_hup(struct vcc_port *port)
783{
784 unsigned long flags;
785
786 spin_lock_irqsave(&port->lock, flags);
787
788 if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
789 vcc_kick_tx(port);
790
791 spin_unlock_irqrestore(&port->lock, flags);
792}
793
794static void vcc_hangup(struct tty_struct *tty)
795{
796 struct vcc_port *port;
797
798 port = vcc_get_ne(tty->index);
799 if (unlikely(!port)) {
800 pr_err("VCC: hangup: Failed to find VCC port\n");
801 return;
802 }
803
804 if (unlikely(!tty->port)) {
805 pr_err("VCC: hangup: TTY port not found\n");
806 vcc_put(port, false);
807 return;
808 }
809
810 vcc_ldc_hup(port);
811
812 vcc_put(port, false);
813
814 tty_port_hangup(tty->port);
815}
816
817static ssize_t vcc_write(struct tty_struct *tty, const u8 *buf, size_t count)
818{
819 struct vcc_port *port;
820 struct vio_vcc *pkt;
821 unsigned long flags;
822 size_t total_sent = 0;
823 size_t tosend = 0;
824 int rv = -EINVAL;
825
826 port = vcc_get_ne(tty->index);
827 if (unlikely(!port)) {
828 pr_err("VCC: write: Failed to find VCC port");
829 return -ENODEV;
830 }
831
832 spin_lock_irqsave(&port->lock, flags);
833
834 pkt = &port->buffer;
835 pkt->tag.type = VIO_TYPE_DATA;
836
837 while (count > 0) {
838 /* Minimum of data to write and space available */
839 tosend = min_t(size_t, count,
840 (VCC_BUFF_LEN - port->chars_in_buffer));
841
842 if (!tosend)
843 break;
844
845 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
846 tosend);
847 port->chars_in_buffer += tosend;
848 pkt->tag.stype = tosend;
849
850 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
851 pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
852 vccdbg("DATA [%s]\n", pkt->data);
853 vccdbgl(port->vio.lp);
854
855 /* Since we know we have enough room in VCC buffer for tosend
856 * we record that it was sent regardless of whether the
857 * hypervisor actually took it because we have it buffered.
858 */
859 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
860 vccdbg("VCC: write: ldc_write(%zu)=%d\n",
861 (VIO_TAG_SIZE + tosend), rv);
862
863 total_sent += tosend;
864 count -= tosend;
865 if (rv < 0) {
866 vcc_kick_tx(port);
867 break;
868 }
869
870 port->chars_in_buffer = 0;
871 }
872
873 spin_unlock_irqrestore(&port->lock, flags);
874
875 vcc_put(port, false);
876
877 vccdbg("VCC: write: total=%zu rv=%d", total_sent, rv);
878
879 return total_sent ? total_sent : rv;
880}
881
882static unsigned int vcc_write_room(struct tty_struct *tty)
883{
884 struct vcc_port *port;
885 unsigned int num;
886
887 port = vcc_get_ne(tty->index);
888 if (unlikely(!port)) {
889 pr_err("VCC: write_room: Failed to find VCC port\n");
890 return 0;
891 }
892
893 num = VCC_BUFF_LEN - port->chars_in_buffer;
894
895 vcc_put(port, false);
896
897 return num;
898}
899
900static unsigned int vcc_chars_in_buffer(struct tty_struct *tty)
901{
902 struct vcc_port *port;
903 unsigned int num;
904
905 port = vcc_get_ne(tty->index);
906 if (unlikely(!port)) {
907 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
908 return 0;
909 }
910
911 num = port->chars_in_buffer;
912
913 vcc_put(port, false);
914
915 return num;
916}
917
918static int vcc_break_ctl(struct tty_struct *tty, int state)
919{
920 struct vcc_port *port;
921 unsigned long flags;
922
923 port = vcc_get_ne(tty->index);
924 if (unlikely(!port)) {
925 pr_err("VCC: break_ctl: Failed to find VCC port\n");
926 return -ENODEV;
927 }
928
929 /* Turn off break */
930 if (state == 0) {
931 vcc_put(port, false);
932 return 0;
933 }
934
935 spin_lock_irqsave(&port->lock, flags);
936
937 if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
938 vcc_kick_tx(port);
939
940 spin_unlock_irqrestore(&port->lock, flags);
941
942 vcc_put(port, false);
943
944 return 0;
945}
946
947static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
948{
949 struct vcc_port *port_vcc;
950 struct tty_port *port_tty;
951 int ret;
952
953 if (tty->index >= VCC_MAX_PORTS)
954 return -EINVAL;
955
956 ret = tty_standard_install(driver, tty);
957 if (ret)
958 return ret;
959
960 port_tty = kzalloc_obj(struct tty_port);
961 if (!port_tty)
962 return -ENOMEM;
963
964 port_vcc = vcc_get(tty->index, true);
965 if (!port_vcc) {
966 pr_err("VCC: install: Failed to find VCC port\n");
967 tty->port = NULL;
968 kfree(port_tty);
969 return -ENODEV;
970 }
971
972 tty_port_init(port_tty);
973 port_tty->ops = &vcc_port_ops;
974 tty->port = port_tty;
975
976 port_vcc->tty = tty;
977
978 vcc_put(port_vcc, true);
979
980 return 0;
981}
982
983static void vcc_cleanup(struct tty_struct *tty)
984{
985 struct vcc_port *port;
986
987 port = vcc_get(tty->index, true);
988 if (port) {
989 scoped_guard(spinlock_irqsave, &port->lock)
990 port->tty = NULL;
991
992 if (port->removed) {
993 vcc_table_remove(tty->index);
994 kfree(port->vio.name);
995 kfree(port->domain);
996 kfree(port);
997 } else {
998 vcc_put(port, true);
999 }
1000 }
1001
1002 tty_port_destroy(tty->port);
1003 kfree(tty->port);
1004 tty->port = NULL;
1005}
1006
1007static const struct tty_operations vcc_ops = {
1008 .open = vcc_open,
1009 .close = vcc_close,
1010 .hangup = vcc_hangup,
1011 .write = vcc_write,
1012 .write_room = vcc_write_room,
1013 .chars_in_buffer = vcc_chars_in_buffer,
1014 .break_ctl = vcc_break_ctl,
1015 .install = vcc_install,
1016 .cleanup = vcc_cleanup,
1017};
1018
1019#define VCC_TTY_FLAGS (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1020
1021static int vcc_tty_init(void)
1022{
1023 int rv;
1024
1025 vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1026 if (IS_ERR(vcc_tty_driver)) {
1027 pr_err("VCC: TTY driver alloc failed\n");
1028 return PTR_ERR(vcc_tty_driver);
1029 }
1030
1031 vcc_tty_driver->driver_name = "vcc";
1032 vcc_tty_driver->name = "vcc";
1033
1034 vcc_tty_driver->minor_start = VCC_MINOR_START;
1035 vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1036 vcc_tty_driver->init_termios = vcc_tty_termios;
1037
1038 tty_set_operations(vcc_tty_driver, &vcc_ops);
1039
1040 rv = tty_register_driver(vcc_tty_driver);
1041 if (rv) {
1042 pr_err("VCC: TTY driver registration failed\n");
1043 tty_driver_kref_put(vcc_tty_driver);
1044 vcc_tty_driver = NULL;
1045 return rv;
1046 }
1047
1048 vccdbg("VCC: TTY driver registered\n");
1049
1050 return 0;
1051}
1052
1053static void vcc_tty_exit(void)
1054{
1055 tty_unregister_driver(vcc_tty_driver);
1056 tty_driver_kref_put(vcc_tty_driver);
1057 vccdbg("VCC: TTY driver unregistered\n");
1058
1059 vcc_tty_driver = NULL;
1060}
1061
1062static int __init vcc_init(void)
1063{
1064 int rv;
1065
1066 rv = vcc_tty_init();
1067 if (rv) {
1068 pr_err("VCC: TTY init failed\n");
1069 return rv;
1070 }
1071
1072 rv = vio_register_driver(&vcc_driver);
1073 if (rv) {
1074 pr_err("VCC: VIO driver registration failed\n");
1075 vcc_tty_exit();
1076 } else {
1077 vccdbg("VCC: VIO driver registered successfully\n");
1078 }
1079
1080 return rv;
1081}
1082
1083static void __exit vcc_exit(void)
1084{
1085 vio_unregister_driver(&vcc_driver);
1086 vccdbg("VCC: VIO driver unregistered\n");
1087 vcc_tty_exit();
1088 vccdbg("VCC: TTY driver unregistered\n");
1089}
1090
1091module_init(vcc_init);
1092module_exit(vcc_exit);