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1 /*
2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
3 * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
4 * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20 #include <linux/cdev.h>
21 #include <linux/debugfs.h>
22 #include <linux/completion.h>
23 #include <linux/device.h>
24 #include <linux/err.h>
25 #include <linux/freezer.h>
26 #include <linux/fs.h>
27 #include <linux/init.h>
28 #include <linux/list.h>
29 #include <linux/poll.h>
30 #include <linux/sched.h>
31 #include <linux/slab.h>
32 #include <linux/spinlock.h>
33 #include <linux/virtio.h>
34 #include <linux/virtio_console.h>
35 #include <linux/wait.h>
36 #include <linux/workqueue.h>
37 #include <linux/module.h>
38 #include "../tty/hvc/hvc_console.h"
39
40 /*
41 * This is a global struct for storing common data for all the devices
42 * this driver handles.
43 *
44 * Mainly, it has a linked list for all the consoles in one place so
45 * that callbacks from hvc for get_chars(), put_chars() work properly
46 * across multiple devices and multiple ports per device.
47 */
48 struct ports_driver_data {
49 /* Used for registering chardevs */
50 struct class *class;
51
52 /* Used for exporting per-port information to debugfs */
53 struct dentry *debugfs_dir;
54
55 /* List of all the devices we're handling */
56 struct list_head portdevs;
57
58 /* Number of devices this driver is handling */
59 unsigned int index;
60
61 /*
62 * This is used to keep track of the number of hvc consoles
63 * spawned by this driver. This number is given as the first
64 * argument to hvc_alloc(). To correctly map an initial
65 * console spawned via hvc_instantiate to the console being
66 * hooked up via hvc_alloc, we need to pass the same vtermno.
67 *
68 * We also just assume the first console being initialised was
69 * the first one that got used as the initial console.
70 */
71 unsigned int next_vtermno;
72
73 /* All the console devices handled by this driver */
74 struct list_head consoles;
75 };
76 static struct ports_driver_data pdrvdata;
77
78 DEFINE_SPINLOCK(pdrvdata_lock);
79 DECLARE_COMPLETION(early_console_added);
80
81 /* This struct holds information that's relevant only for console ports */
82 struct console {
83 /* We'll place all consoles in a list in the pdrvdata struct */
84 struct list_head list;
85
86 /* The hvc device associated with this console port */
87 struct hvc_struct *hvc;
88
89 /* The size of the console */
90 struct winsize ws;
91
92 /*
93 * This number identifies the number that we used to register
94 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
95 * number passed on by the hvc callbacks to us to
96 * differentiate between the other console ports handled by
97 * this driver
98 */
99 u32 vtermno;
100 };
101
102 struct port_buffer {
103 char *buf;
104
105 /* size of the buffer in *buf above */
106 size_t size;
107
108 /* used length of the buffer */
109 size_t len;
110 /* offset in the buf from which to consume data */
111 size_t offset;
112 };
113
114 /*
115 * This is a per-device struct that stores data common to all the
116 * ports for that device (vdev->priv).
117 */
118 struct ports_device {
119 /* Next portdev in the list, head is in the pdrvdata struct */
120 struct list_head list;
121
122 /*
123 * Workqueue handlers where we process deferred work after
124 * notification
125 */
126 struct work_struct control_work;
127
128 struct list_head ports;
129
130 /* To protect the list of ports */
131 spinlock_t ports_lock;
132
133 /* To protect the vq operations for the control channel */
134 spinlock_t cvq_lock;
135
136 /* The current config space is stored here */
137 struct virtio_console_config config;
138
139 /* The virtio device we're associated with */
140 struct virtio_device *vdev;
141
142 /*
143 * A couple of virtqueues for the control channel: one for
144 * guest->host transfers, one for host->guest transfers
145 */
146 struct virtqueue *c_ivq, *c_ovq;
147
148 /* Array of per-port IO virtqueues */
149 struct virtqueue **in_vqs, **out_vqs;
150
151 /* Used for numbering devices for sysfs and debugfs */
152 unsigned int drv_index;
153
154 /* Major number for this device. Ports will be created as minors. */
155 int chr_major;
156 };
157
158 struct port_stats {
159 unsigned long bytes_sent, bytes_received, bytes_discarded;
160 };
161
162 /* This struct holds the per-port data */
163 struct port {
164 /* Next port in the list, head is in the ports_device */
165 struct list_head list;
166
167 /* Pointer to the parent virtio_console device */
168 struct ports_device *portdev;
169
170 /* The current buffer from which data has to be fed to readers */
171 struct port_buffer *inbuf;
172
173 /*
174 * To protect the operations on the in_vq associated with this
175 * port. Has to be a spinlock because it can be called from
176 * interrupt context (get_char()).
177 */
178 spinlock_t inbuf_lock;
179
180 /* Protect the operations on the out_vq. */
181 spinlock_t outvq_lock;
182
183 /* The IO vqs for this port */
184 struct virtqueue *in_vq, *out_vq;
185
186 /* File in the debugfs directory that exposes this port's information */
187 struct dentry *debugfs_file;
188
189 /*
190 * Keep count of the bytes sent, received and discarded for
191 * this port for accounting and debugging purposes. These
192 * counts are not reset across port open / close events.
193 */
194 struct port_stats stats;
195
196 /*
197 * The entries in this struct will be valid if this port is
198 * hooked up to an hvc console
199 */
200 struct console cons;
201
202 /* Each port associates with a separate char device */
203 struct cdev *cdev;
204 struct device *dev;
205
206 /* Reference-counting to handle port hot-unplugs and file operations */
207 struct kref kref;
208
209 /* A waitqueue for poll() or blocking read operations */
210 wait_queue_head_t waitqueue;
211
212 /* The 'name' of the port that we expose via sysfs properties */
213 char *name;
214
215 /* We can notify apps of host connect / disconnect events via SIGIO */
216 struct fasync_struct *async_queue;
217
218 /* The 'id' to identify the port with the Host */
219 u32 id;
220
221 bool outvq_full;
222
223 /* Is the host device open */
224 bool host_connected;
225
226 /* We should allow only one process to open a port */
227 bool guest_connected;
228 };
229
230 /* This is the very early arch-specified put chars function. */
231 static int (*early_put_chars)(u32, const char *, int);
232
233 static struct port *find_port_by_vtermno(u32 vtermno)
234 {
235 struct port *port;
236 struct console *cons;
237 unsigned long flags;
238
239 spin_lock_irqsave(&pdrvdata_lock, flags);
240 list_for_each_entry(cons, &pdrvdata.consoles, list) {
241 if (cons->vtermno == vtermno) {
242 port = container_of(cons, struct port, cons);
243 goto out;
244 }
245 }
246 port = NULL;
247 out:
248 spin_unlock_irqrestore(&pdrvdata_lock, flags);
249 return port;
250 }
251
252 static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
253 dev_t dev)
254 {
255 struct port *port;
256 unsigned long flags;
257
258 spin_lock_irqsave(&portdev->ports_lock, flags);
259 list_for_each_entry(port, &portdev->ports, list)
260 if (port->cdev->dev == dev)
261 goto out;
262 port = NULL;
263 out:
264 spin_unlock_irqrestore(&portdev->ports_lock, flags);
265
266 return port;
267 }
268
269 static struct port *find_port_by_devt(dev_t dev)
270 {
271 struct ports_device *portdev;
272 struct port *port;
273 unsigned long flags;
274
275 spin_lock_irqsave(&pdrvdata_lock, flags);
276 list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
277 port = find_port_by_devt_in_portdev(portdev, dev);
278 if (port)
279 goto out;
280 }
281 port = NULL;
282 out:
283 spin_unlock_irqrestore(&pdrvdata_lock, flags);
284 return port;
285 }
286
287 static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
288 {
289 struct port *port;
290 unsigned long flags;
291
292 spin_lock_irqsave(&portdev->ports_lock, flags);
293 list_for_each_entry(port, &portdev->ports, list)
294 if (port->id == id)
295 goto out;
296 port = NULL;
297 out:
298 spin_unlock_irqrestore(&portdev->ports_lock, flags);
299
300 return port;
301 }
302
303 static struct port *find_port_by_vq(struct ports_device *portdev,
304 struct virtqueue *vq)
305 {
306 struct port *port;
307 unsigned long flags;
308
309 spin_lock_irqsave(&portdev->ports_lock, flags);
310 list_for_each_entry(port, &portdev->ports, list)
311 if (port->in_vq == vq || port->out_vq == vq)
312 goto out;
313 port = NULL;
314 out:
315 spin_unlock_irqrestore(&portdev->ports_lock, flags);
316 return port;
317 }
318
319 static bool is_console_port(struct port *port)
320 {
321 if (port->cons.hvc)
322 return true;
323 return false;
324 }
325
326 static inline bool use_multiport(struct ports_device *portdev)
327 {
328 /*
329 * This condition can be true when put_chars is called from
330 * early_init
331 */
332 if (!portdev->vdev)
333 return 0;
334 return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
335 }
336
337 static void free_buf(struct port_buffer *buf)
338 {
339 kfree(buf->buf);
340 kfree(buf);
341 }
342
343 static struct port_buffer *alloc_buf(size_t buf_size)
344 {
345 struct port_buffer *buf;
346
347 buf = kmalloc(sizeof(*buf), GFP_KERNEL);
348 if (!buf)
349 goto fail;
350 buf->buf = kzalloc(buf_size, GFP_KERNEL);
351 if (!buf->buf)
352 goto free_buf;
353 buf->len = 0;
354 buf->offset = 0;
355 buf->size = buf_size;
356 return buf;
357
358 free_buf:
359 kfree(buf);
360 fail:
361 return NULL;
362 }
363
364 /* Callers should take appropriate locks */
365 static struct port_buffer *get_inbuf(struct port *port)
366 {
367 struct port_buffer *buf;
368 unsigned int len;
369
370 if (port->inbuf)
371 return port->inbuf;
372
373 buf = virtqueue_get_buf(port->in_vq, &len);
374 if (buf) {
375 buf->len = len;
376 buf->offset = 0;
377 port->stats.bytes_received += len;
378 }
379 return buf;
380 }
381
382 /*
383 * Create a scatter-gather list representing our input buffer and put
384 * it in the queue.
385 *
386 * Callers should take appropriate locks.
387 */
388 static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
389 {
390 struct scatterlist sg[1];
391 int ret;
392
393 sg_init_one(sg, buf->buf, buf->size);
394
395 ret = virtqueue_add_buf(vq, sg, 0, 1, buf);
396 virtqueue_kick(vq);
397 return ret;
398 }
399
400 /* Discard any unread data this port has. Callers lockers. */
401 static void discard_port_data(struct port *port)
402 {
403 struct port_buffer *buf;
404 unsigned int err;
405
406 if (!port->portdev) {
407 /* Device has been unplugged. vqs are already gone. */
408 return;
409 }
410 buf = get_inbuf(port);
411
412 err = 0;
413 while (buf) {
414 port->stats.bytes_discarded += buf->len - buf->offset;
415 if (add_inbuf(port->in_vq, buf) < 0) {
416 err++;
417 free_buf(buf);
418 }
419 port->inbuf = NULL;
420 buf = get_inbuf(port);
421 }
422 if (err)
423 dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
424 err);
425 }
426
427 static bool port_has_data(struct port *port)
428 {
429 unsigned long flags;
430 bool ret;
431
432 ret = false;
433 spin_lock_irqsave(&port->inbuf_lock, flags);
434 port->inbuf = get_inbuf(port);
435 if (port->inbuf)
436 ret = true;
437
438 spin_unlock_irqrestore(&port->inbuf_lock, flags);
439 return ret;
440 }
441
442 static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
443 unsigned int event, unsigned int value)
444 {
445 struct scatterlist sg[1];
446 struct virtio_console_control cpkt;
447 struct virtqueue *vq;
448 unsigned int len;
449
450 if (!use_multiport(portdev))
451 return 0;
452
453 cpkt.id = port_id;
454 cpkt.event = event;
455 cpkt.value = value;
456
457 vq = portdev->c_ovq;
458
459 sg_init_one(sg, &cpkt, sizeof(cpkt));
460 if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
461 virtqueue_kick(vq);
462 while (!virtqueue_get_buf(vq, &len))
463 cpu_relax();
464 }
465 return 0;
466 }
467
468 static ssize_t send_control_msg(struct port *port, unsigned int event,
469 unsigned int value)
470 {
471 /* Did the port get unplugged before userspace closed it? */
472 if (port->portdev)
473 return __send_control_msg(port->portdev, port->id, event, value);
474 return 0;
475 }
476
477 /* Callers must take the port->outvq_lock */
478 static void reclaim_consumed_buffers(struct port *port)
479 {
480 void *buf;
481 unsigned int len;
482
483 if (!port->portdev) {
484 /* Device has been unplugged. vqs are already gone. */
485 return;
486 }
487 while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
488 kfree(buf);
489 port->outvq_full = false;
490 }
491 }
492
493 static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
494 bool nonblock)
495 {
496 struct scatterlist sg[1];
497 struct virtqueue *out_vq;
498 ssize_t ret;
499 unsigned long flags;
500 unsigned int len;
501
502 out_vq = port->out_vq;
503
504 spin_lock_irqsave(&port->outvq_lock, flags);
505
506 reclaim_consumed_buffers(port);
507
508 sg_init_one(sg, in_buf, in_count);
509 ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf);
510
511 /* Tell Host to go! */
512 virtqueue_kick(out_vq);
513
514 if (ret < 0) {
515 in_count = 0;
516 goto done;
517 }
518
519 if (ret == 0)
520 port->outvq_full = true;
521
522 if (nonblock)
523 goto done;
524
525 /*
526 * Wait till the host acknowledges it pushed out the data we
527 * sent. This is done for data from the hvc_console; the tty
528 * operations are performed with spinlocks held so we can't
529 * sleep here. An alternative would be to copy the data to a
530 * buffer and relax the spinning requirement. The downside is
531 * we need to kmalloc a GFP_ATOMIC buffer each time the
532 * console driver writes something out.
533 */
534 while (!virtqueue_get_buf(out_vq, &len))
535 cpu_relax();
536 done:
537 spin_unlock_irqrestore(&port->outvq_lock, flags);
538
539 port->stats.bytes_sent += in_count;
540 /*
541 * We're expected to return the amount of data we wrote -- all
542 * of it
543 */
544 return in_count;
545 }
546
547 /*
548 * Give out the data that's requested from the buffer that we have
549 * queued up.
550 */
551 static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
552 bool to_user)
553 {
554 struct port_buffer *buf;
555 unsigned long flags;
556
557 if (!out_count || !port_has_data(port))
558 return 0;
559
560 buf = port->inbuf;
561 out_count = min(out_count, buf->len - buf->offset);
562
563 if (to_user) {
564 ssize_t ret;
565
566 ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
567 if (ret)
568 return -EFAULT;
569 } else {
570 memcpy(out_buf, buf->buf + buf->offset, out_count);
571 }
572
573 buf->offset += out_count;
574
575 if (buf->offset == buf->len) {
576 /*
577 * We're done using all the data in this buffer.
578 * Re-queue so that the Host can send us more data.
579 */
580 spin_lock_irqsave(&port->inbuf_lock, flags);
581 port->inbuf = NULL;
582
583 if (add_inbuf(port->in_vq, buf) < 0)
584 dev_warn(port->dev, "failed add_buf\n");
585
586 spin_unlock_irqrestore(&port->inbuf_lock, flags);
587 }
588 /* Return the number of bytes actually copied */
589 return out_count;
590 }
591
592 /* The condition that must be true for polling to end */
593 static bool will_read_block(struct port *port)
594 {
595 if (!port->guest_connected) {
596 /* Port got hot-unplugged. Let's exit. */
597 return false;
598 }
599 return !port_has_data(port) && port->host_connected;
600 }
601
602 static bool will_write_block(struct port *port)
603 {
604 bool ret;
605
606 if (!port->guest_connected) {
607 /* Port got hot-unplugged. Let's exit. */
608 return false;
609 }
610 if (!port->host_connected)
611 return true;
612
613 spin_lock_irq(&port->outvq_lock);
614 /*
615 * Check if the Host has consumed any buffers since we last
616 * sent data (this is only applicable for nonblocking ports).
617 */
618 reclaim_consumed_buffers(port);
619 ret = port->outvq_full;
620 spin_unlock_irq(&port->outvq_lock);
621
622 return ret;
623 }
624
625 static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
626 size_t count, loff_t *offp)
627 {
628 struct port *port;
629 ssize_t ret;
630
631 port = filp->private_data;
632
633 if (!port_has_data(port)) {
634 /*
635 * If nothing's connected on the host just return 0 in
636 * case of list_empty; this tells the userspace app
637 * that there's no connection
638 */
639 if (!port->host_connected)
640 return 0;
641 if (filp->f_flags & O_NONBLOCK)
642 return -EAGAIN;
643
644 ret = wait_event_freezable(port->waitqueue,
645 !will_read_block(port));
646 if (ret < 0)
647 return ret;
648 }
649 /* Port got hot-unplugged. */
650 if (!port->guest_connected)
651 return -ENODEV;
652 /*
653 * We could've received a disconnection message while we were
654 * waiting for more data.
655 *
656 * This check is not clubbed in the if() statement above as we
657 * might receive some data as well as the host could get
658 * disconnected after we got woken up from our wait. So we
659 * really want to give off whatever data we have and only then
660 * check for host_connected.
661 */
662 if (!port_has_data(port) && !port->host_connected)
663 return 0;
664
665 return fill_readbuf(port, ubuf, count, true);
666 }
667
668 static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
669 size_t count, loff_t *offp)
670 {
671 struct port *port;
672 char *buf;
673 ssize_t ret;
674 bool nonblock;
675
676 /* Userspace could be out to fool us */
677 if (!count)
678 return 0;
679
680 port = filp->private_data;
681
682 nonblock = filp->f_flags & O_NONBLOCK;
683
684 if (will_write_block(port)) {
685 if (nonblock)
686 return -EAGAIN;
687
688 ret = wait_event_freezable(port->waitqueue,
689 !will_write_block(port));
690 if (ret < 0)
691 return ret;
692 }
693 /* Port got hot-unplugged. */
694 if (!port->guest_connected)
695 return -ENODEV;
696
697 count = min((size_t)(32 * 1024), count);
698
699 buf = kmalloc(count, GFP_KERNEL);
700 if (!buf)
701 return -ENOMEM;
702
703 ret = copy_from_user(buf, ubuf, count);
704 if (ret) {
705 ret = -EFAULT;
706 goto free_buf;
707 }
708
709 /*
710 * We now ask send_buf() to not spin for generic ports -- we
711 * can re-use the same code path that non-blocking file
712 * descriptors take for blocking file descriptors since the
713 * wait is already done and we're certain the write will go
714 * through to the host.
715 */
716 nonblock = true;
717 ret = send_buf(port, buf, count, nonblock);
718
719 if (nonblock && ret > 0)
720 goto out;
721
722 free_buf:
723 kfree(buf);
724 out:
725 return ret;
726 }
727
728 static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
729 {
730 struct port *port;
731 unsigned int ret;
732
733 port = filp->private_data;
734 poll_wait(filp, &port->waitqueue, wait);
735
736 if (!port->guest_connected) {
737 /* Port got unplugged */
738 return POLLHUP;
739 }
740 ret = 0;
741 if (!will_read_block(port))
742 ret |= POLLIN | POLLRDNORM;
743 if (!will_write_block(port))
744 ret |= POLLOUT;
745 if (!port->host_connected)
746 ret |= POLLHUP;
747
748 return ret;
749 }
750
751 static void remove_port(struct kref *kref);
752
753 static int port_fops_release(struct inode *inode, struct file *filp)
754 {
755 struct port *port;
756
757 port = filp->private_data;
758
759 /* Notify host of port being closed */
760 send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
761
762 spin_lock_irq(&port->inbuf_lock);
763 port->guest_connected = false;
764
765 discard_port_data(port);
766
767 spin_unlock_irq(&port->inbuf_lock);
768
769 spin_lock_irq(&port->outvq_lock);
770 reclaim_consumed_buffers(port);
771 spin_unlock_irq(&port->outvq_lock);
772
773 /*
774 * Locks aren't necessary here as a port can't be opened after
775 * unplug, and if a port isn't unplugged, a kref would already
776 * exist for the port. Plus, taking ports_lock here would
777 * create a dependency on other locks taken by functions
778 * inside remove_port if we're the last holder of the port,
779 * creating many problems.
780 */
781 kref_put(&port->kref, remove_port);
782
783 return 0;
784 }
785
786 static int port_fops_open(struct inode *inode, struct file *filp)
787 {
788 struct cdev *cdev = inode->i_cdev;
789 struct port *port;
790 int ret;
791
792 port = find_port_by_devt(cdev->dev);
793 filp->private_data = port;
794
795 /* Prevent against a port getting hot-unplugged at the same time */
796 spin_lock_irq(&port->portdev->ports_lock);
797 kref_get(&port->kref);
798 spin_unlock_irq(&port->portdev->ports_lock);
799
800 /*
801 * Don't allow opening of console port devices -- that's done
802 * via /dev/hvc
803 */
804 if (is_console_port(port)) {
805 ret = -ENXIO;
806 goto out;
807 }
808
809 /* Allow only one process to open a particular port at a time */
810 spin_lock_irq(&port->inbuf_lock);
811 if (port->guest_connected) {
812 spin_unlock_irq(&port->inbuf_lock);
813 ret = -EMFILE;
814 goto out;
815 }
816
817 port->guest_connected = true;
818 spin_unlock_irq(&port->inbuf_lock);
819
820 spin_lock_irq(&port->outvq_lock);
821 /*
822 * There might be a chance that we missed reclaiming a few
823 * buffers in the window of the port getting previously closed
824 * and opening now.
825 */
826 reclaim_consumed_buffers(port);
827 spin_unlock_irq(&port->outvq_lock);
828
829 nonseekable_open(inode, filp);
830
831 /* Notify host of port being opened */
832 send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
833
834 return 0;
835 out:
836 kref_put(&port->kref, remove_port);
837 return ret;
838 }
839
840 static int port_fops_fasync(int fd, struct file *filp, int mode)
841 {
842 struct port *port;
843
844 port = filp->private_data;
845 return fasync_helper(fd, filp, mode, &port->async_queue);
846 }
847
848 /*
849 * The file operations that we support: programs in the guest can open
850 * a console device, read from it, write to it, poll for data and
851 * close it. The devices are at
852 * /dev/vport<device number>p<port number>
853 */
854 static const struct file_operations port_fops = {
855 .owner = THIS_MODULE,
856 .open = port_fops_open,
857 .read = port_fops_read,
858 .write = port_fops_write,
859 .poll = port_fops_poll,
860 .release = port_fops_release,
861 .fasync = port_fops_fasync,
862 .llseek = no_llseek,
863 };
864
865 /*
866 * The put_chars() callback is pretty straightforward.
867 *
868 * We turn the characters into a scatter-gather list, add it to the
869 * output queue and then kick the Host. Then we sit here waiting for
870 * it to finish: inefficient in theory, but in practice
871 * implementations will do it immediately (lguest's Launcher does).
872 */
873 static int put_chars(u32 vtermno, const char *buf, int count)
874 {
875 struct port *port;
876
877 if (unlikely(early_put_chars))
878 return early_put_chars(vtermno, buf, count);
879
880 port = find_port_by_vtermno(vtermno);
881 if (!port)
882 return -EPIPE;
883
884 return send_buf(port, (void *)buf, count, false);
885 }
886
887 /*
888 * get_chars() is the callback from the hvc_console infrastructure
889 * when an interrupt is received.
890 *
891 * We call out to fill_readbuf that gets us the required data from the
892 * buffers that are queued up.
893 */
894 static int get_chars(u32 vtermno, char *buf, int count)
895 {
896 struct port *port;
897
898 /* If we've not set up the port yet, we have no input to give. */
899 if (unlikely(early_put_chars))
900 return 0;
901
902 port = find_port_by_vtermno(vtermno);
903 if (!port)
904 return -EPIPE;
905
906 /* If we don't have an input queue yet, we can't get input. */
907 BUG_ON(!port->in_vq);
908
909 return fill_readbuf(port, buf, count, false);
910 }
911
912 static void resize_console(struct port *port)
913 {
914 struct virtio_device *vdev;
915
916 /* The port could have been hot-unplugged */
917 if (!port || !is_console_port(port))
918 return;
919
920 vdev = port->portdev->vdev;
921 if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
922 hvc_resize(port->cons.hvc, port->cons.ws);
923 }
924
925 /* We set the configuration at this point, since we now have a tty */
926 static int notifier_add_vio(struct hvc_struct *hp, int data)
927 {
928 struct port *port;
929
930 port = find_port_by_vtermno(hp->vtermno);
931 if (!port)
932 return -EINVAL;
933
934 hp->irq_requested = 1;
935 resize_console(port);
936
937 return 0;
938 }
939
940 static void notifier_del_vio(struct hvc_struct *hp, int data)
941 {
942 hp->irq_requested = 0;
943 }
944
945 /* The operations for console ports. */
946 static const struct hv_ops hv_ops = {
947 .get_chars = get_chars,
948 .put_chars = put_chars,
949 .notifier_add = notifier_add_vio,
950 .notifier_del = notifier_del_vio,
951 .notifier_hangup = notifier_del_vio,
952 };
953
954 /*
955 * Console drivers are initialized very early so boot messages can go
956 * out, so we do things slightly differently from the generic virtio
957 * initialization of the net and block drivers.
958 *
959 * At this stage, the console is output-only. It's too early to set
960 * up a virtqueue, so we let the drivers do some boutique early-output
961 * thing.
962 */
963 int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
964 {
965 early_put_chars = put_chars;
966 return hvc_instantiate(0, 0, &hv_ops);
967 }
968
969 int init_port_console(struct port *port)
970 {
971 int ret;
972
973 /*
974 * The Host's telling us this port is a console port. Hook it
975 * up with an hvc console.
976 *
977 * To set up and manage our virtual console, we call
978 * hvc_alloc().
979 *
980 * The first argument of hvc_alloc() is the virtual console
981 * number. The second argument is the parameter for the
982 * notification mechanism (like irq number). We currently
983 * leave this as zero, virtqueues have implicit notifications.
984 *
985 * The third argument is a "struct hv_ops" containing the
986 * put_chars() get_chars(), notifier_add() and notifier_del()
987 * pointers. The final argument is the output buffer size: we
988 * can do any size, so we put PAGE_SIZE here.
989 */
990 port->cons.vtermno = pdrvdata.next_vtermno;
991
992 port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
993 if (IS_ERR(port->cons.hvc)) {
994 ret = PTR_ERR(port->cons.hvc);
995 dev_err(port->dev,
996 "error %d allocating hvc for port\n", ret);
997 port->cons.hvc = NULL;
998 return ret;
999 }
1000 spin_lock_irq(&pdrvdata_lock);
1001 pdrvdata.next_vtermno++;
1002 list_add_tail(&port->cons.list, &pdrvdata.consoles);
1003 spin_unlock_irq(&pdrvdata_lock);
1004 port->guest_connected = true;
1005
1006 /*
1007 * Start using the new console output if this is the first
1008 * console to come up.
1009 */
1010 if (early_put_chars)
1011 early_put_chars = NULL;
1012
1013 /* Notify host of port being opened */
1014 send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1015
1016 return 0;
1017 }
1018
1019 static ssize_t show_port_name(struct device *dev,
1020 struct device_attribute *attr, char *buffer)
1021 {
1022 struct port *port;
1023
1024 port = dev_get_drvdata(dev);
1025
1026 return sprintf(buffer, "%s\n", port->name);
1027 }
1028
1029 static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1030
1031 static struct attribute *port_sysfs_entries[] = {
1032 &dev_attr_name.attr,
1033 NULL
1034 };
1035
1036 static struct attribute_group port_attribute_group = {
1037 .name = NULL, /* put in device directory */
1038 .attrs = port_sysfs_entries,
1039 };
1040
1041 static int debugfs_open(struct inode *inode, struct file *filp)
1042 {
1043 filp->private_data = inode->i_private;
1044 return 0;
1045 }
1046
1047 static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1048 size_t count, loff_t *offp)
1049 {
1050 struct port *port;
1051 char *buf;
1052 ssize_t ret, out_offset, out_count;
1053
1054 out_count = 1024;
1055 buf = kmalloc(out_count, GFP_KERNEL);
1056 if (!buf)
1057 return -ENOMEM;
1058
1059 port = filp->private_data;
1060 out_offset = 0;
1061 out_offset += snprintf(buf + out_offset, out_count,
1062 "name: %s\n", port->name ? port->name : "");
1063 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1064 "guest_connected: %d\n", port->guest_connected);
1065 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1066 "host_connected: %d\n", port->host_connected);
1067 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1068 "outvq_full: %d\n", port->outvq_full);
1069 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1070 "bytes_sent: %lu\n", port->stats.bytes_sent);
1071 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1072 "bytes_received: %lu\n",
1073 port->stats.bytes_received);
1074 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1075 "bytes_discarded: %lu\n",
1076 port->stats.bytes_discarded);
1077 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1078 "is_console: %s\n",
1079 is_console_port(port) ? "yes" : "no");
1080 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1081 "console_vtermno: %u\n", port->cons.vtermno);
1082
1083 ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1084 kfree(buf);
1085 return ret;
1086 }
1087
1088 static const struct file_operations port_debugfs_ops = {
1089 .owner = THIS_MODULE,
1090 .open = debugfs_open,
1091 .read = debugfs_read,
1092 };
1093
1094 static void set_console_size(struct port *port, u16 rows, u16 cols)
1095 {
1096 if (!port || !is_console_port(port))
1097 return;
1098
1099 port->cons.ws.ws_row = rows;
1100 port->cons.ws.ws_col = cols;
1101 }
1102
1103 static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1104 {
1105 struct port_buffer *buf;
1106 unsigned int nr_added_bufs;
1107 int ret;
1108
1109 nr_added_bufs = 0;
1110 do {
1111 buf = alloc_buf(PAGE_SIZE);
1112 if (!buf)
1113 break;
1114
1115 spin_lock_irq(lock);
1116 ret = add_inbuf(vq, buf);
1117 if (ret < 0) {
1118 spin_unlock_irq(lock);
1119 free_buf(buf);
1120 break;
1121 }
1122 nr_added_bufs++;
1123 spin_unlock_irq(lock);
1124 } while (ret > 0);
1125
1126 return nr_added_bufs;
1127 }
1128
1129 static void send_sigio_to_port(struct port *port)
1130 {
1131 if (port->async_queue && port->guest_connected)
1132 kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1133 }
1134
1135 static int add_port(struct ports_device *portdev, u32 id)
1136 {
1137 char debugfs_name[16];
1138 struct port *port;
1139 struct port_buffer *buf;
1140 dev_t devt;
1141 unsigned int nr_added_bufs;
1142 int err;
1143
1144 port = kmalloc(sizeof(*port), GFP_KERNEL);
1145 if (!port) {
1146 err = -ENOMEM;
1147 goto fail;
1148 }
1149 kref_init(&port->kref);
1150
1151 port->portdev = portdev;
1152 port->id = id;
1153
1154 port->name = NULL;
1155 port->inbuf = NULL;
1156 port->cons.hvc = NULL;
1157 port->async_queue = NULL;
1158
1159 port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1160
1161 port->host_connected = port->guest_connected = false;
1162 port->stats = (struct port_stats) { 0 };
1163
1164 port->outvq_full = false;
1165
1166 port->in_vq = portdev->in_vqs[port->id];
1167 port->out_vq = portdev->out_vqs[port->id];
1168
1169 port->cdev = cdev_alloc();
1170 if (!port->cdev) {
1171 dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1172 err = -ENOMEM;
1173 goto free_port;
1174 }
1175 port->cdev->ops = &port_fops;
1176
1177 devt = MKDEV(portdev->chr_major, id);
1178 err = cdev_add(port->cdev, devt, 1);
1179 if (err < 0) {
1180 dev_err(&port->portdev->vdev->dev,
1181 "Error %d adding cdev for port %u\n", err, id);
1182 goto free_cdev;
1183 }
1184 port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1185 devt, port, "vport%up%u",
1186 port->portdev->drv_index, id);
1187 if (IS_ERR(port->dev)) {
1188 err = PTR_ERR(port->dev);
1189 dev_err(&port->portdev->vdev->dev,
1190 "Error %d creating device for port %u\n",
1191 err, id);
1192 goto free_cdev;
1193 }
1194
1195 spin_lock_init(&port->inbuf_lock);
1196 spin_lock_init(&port->outvq_lock);
1197 init_waitqueue_head(&port->waitqueue);
1198
1199 /* Fill the in_vq with buffers so the host can send us data. */
1200 nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1201 if (!nr_added_bufs) {
1202 dev_err(port->dev, "Error allocating inbufs\n");
1203 err = -ENOMEM;
1204 goto free_device;
1205 }
1206
1207 /*
1208 * If we're not using multiport support, this has to be a console port
1209 */
1210 if (!use_multiport(port->portdev)) {
1211 err = init_port_console(port);
1212 if (err)
1213 goto free_inbufs;
1214 }
1215
1216 spin_lock_irq(&portdev->ports_lock);
1217 list_add_tail(&port->list, &port->portdev->ports);
1218 spin_unlock_irq(&portdev->ports_lock);
1219
1220 /*
1221 * Tell the Host we're set so that it can send us various
1222 * configuration parameters for this port (eg, port name,
1223 * caching, whether this is a console port, etc.)
1224 */
1225 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1226
1227 if (pdrvdata.debugfs_dir) {
1228 /*
1229 * Finally, create the debugfs file that we can use to
1230 * inspect a port's state at any time
1231 */
1232 sprintf(debugfs_name, "vport%up%u",
1233 port->portdev->drv_index, id);
1234 port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1235 pdrvdata.debugfs_dir,
1236 port,
1237 &port_debugfs_ops);
1238 }
1239 return 0;
1240
1241 free_inbufs:
1242 while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1243 free_buf(buf);
1244 free_device:
1245 device_destroy(pdrvdata.class, port->dev->devt);
1246 free_cdev:
1247 cdev_del(port->cdev);
1248 free_port:
1249 kfree(port);
1250 fail:
1251 /* The host might want to notify management sw about port add failure */
1252 __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1253 return err;
1254 }
1255
1256 /* No users remain, remove all port-specific data. */
1257 static void remove_port(struct kref *kref)
1258 {
1259 struct port *port;
1260
1261 port = container_of(kref, struct port, kref);
1262
1263 sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1264 device_destroy(pdrvdata.class, port->dev->devt);
1265 cdev_del(port->cdev);
1266
1267 kfree(port->name);
1268
1269 debugfs_remove(port->debugfs_file);
1270
1271 kfree(port);
1272 }
1273
1274 /*
1275 * Port got unplugged. Remove port from portdev's list and drop the
1276 * kref reference. If no userspace has this port opened, it will
1277 * result in immediate removal the port.
1278 */
1279 static void unplug_port(struct port *port)
1280 {
1281 struct port_buffer *buf;
1282
1283 spin_lock_irq(&port->portdev->ports_lock);
1284 list_del(&port->list);
1285 spin_unlock_irq(&port->portdev->ports_lock);
1286
1287 if (port->guest_connected) {
1288 port->guest_connected = false;
1289 port->host_connected = false;
1290 wake_up_interruptible(&port->waitqueue);
1291
1292 /* Let the app know the port is going down. */
1293 send_sigio_to_port(port);
1294 }
1295
1296 if (is_console_port(port)) {
1297 spin_lock_irq(&pdrvdata_lock);
1298 list_del(&port->cons.list);
1299 spin_unlock_irq(&pdrvdata_lock);
1300 hvc_remove(port->cons.hvc);
1301 }
1302
1303 /* Remove unused data this port might have received. */
1304 discard_port_data(port);
1305
1306 reclaim_consumed_buffers(port);
1307
1308 /* Remove buffers we queued up for the Host to send us data in. */
1309 while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1310 free_buf(buf);
1311
1312 /*
1313 * We should just assume the device itself has gone off --
1314 * else a close on an open port later will try to send out a
1315 * control message.
1316 */
1317 port->portdev = NULL;
1318
1319 /*
1320 * Locks around here are not necessary - a port can't be
1321 * opened after we removed the port struct from ports_list
1322 * above.
1323 */
1324 kref_put(&port->kref, remove_port);
1325 }
1326
1327 /* Any private messages that the Host and Guest want to share */
1328 static void handle_control_message(struct ports_device *portdev,
1329 struct port_buffer *buf)
1330 {
1331 struct virtio_console_control *cpkt;
1332 struct port *port;
1333 size_t name_size;
1334 int err;
1335
1336 cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1337
1338 port = find_port_by_id(portdev, cpkt->id);
1339 if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
1340 /* No valid header at start of buffer. Drop it. */
1341 dev_dbg(&portdev->vdev->dev,
1342 "Invalid index %u in control packet\n", cpkt->id);
1343 return;
1344 }
1345
1346 switch (cpkt->event) {
1347 case VIRTIO_CONSOLE_PORT_ADD:
1348 if (port) {
1349 dev_dbg(&portdev->vdev->dev,
1350 "Port %u already added\n", port->id);
1351 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1352 break;
1353 }
1354 if (cpkt->id >= portdev->config.max_nr_ports) {
1355 dev_warn(&portdev->vdev->dev,
1356 "Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1357 cpkt->id, portdev->config.max_nr_ports - 1);
1358 break;
1359 }
1360 add_port(portdev, cpkt->id);
1361 break;
1362 case VIRTIO_CONSOLE_PORT_REMOVE:
1363 unplug_port(port);
1364 break;
1365 case VIRTIO_CONSOLE_CONSOLE_PORT:
1366 if (!cpkt->value)
1367 break;
1368 if (is_console_port(port))
1369 break;
1370
1371 init_port_console(port);
1372 complete(&early_console_added);
1373 /*
1374 * Could remove the port here in case init fails - but
1375 * have to notify the host first.
1376 */
1377 break;
1378 case VIRTIO_CONSOLE_RESIZE: {
1379 struct {
1380 __u16 rows;
1381 __u16 cols;
1382 } size;
1383
1384 if (!is_console_port(port))
1385 break;
1386
1387 memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1388 sizeof(size));
1389 set_console_size(port, size.rows, size.cols);
1390
1391 port->cons.hvc->irq_requested = 1;
1392 resize_console(port);
1393 break;
1394 }
1395 case VIRTIO_CONSOLE_PORT_OPEN:
1396 port->host_connected = cpkt->value;
1397 wake_up_interruptible(&port->waitqueue);
1398 /*
1399 * If the host port got closed and the host had any
1400 * unconsumed buffers, we'll be able to reclaim them
1401 * now.
1402 */
1403 spin_lock_irq(&port->outvq_lock);
1404 reclaim_consumed_buffers(port);
1405 spin_unlock_irq(&port->outvq_lock);
1406
1407 /*
1408 * If the guest is connected, it'll be interested in
1409 * knowing the host connection state changed.
1410 */
1411 send_sigio_to_port(port);
1412 break;
1413 case VIRTIO_CONSOLE_PORT_NAME:
1414 /*
1415 * If we woke up after hibernation, we can get this
1416 * again. Skip it in that case.
1417 */
1418 if (port->name)
1419 break;
1420
1421 /*
1422 * Skip the size of the header and the cpkt to get the size
1423 * of the name that was sent
1424 */
1425 name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1426
1427 port->name = kmalloc(name_size, GFP_KERNEL);
1428 if (!port->name) {
1429 dev_err(port->dev,
1430 "Not enough space to store port name\n");
1431 break;
1432 }
1433 strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1434 name_size - 1);
1435 port->name[name_size - 1] = 0;
1436
1437 /*
1438 * Since we only have one sysfs attribute, 'name',
1439 * create it only if we have a name for the port.
1440 */
1441 err = sysfs_create_group(&port->dev->kobj,
1442 &port_attribute_group);
1443 if (err) {
1444 dev_err(port->dev,
1445 "Error %d creating sysfs device attributes\n",
1446 err);
1447 } else {
1448 /*
1449 * Generate a udev event so that appropriate
1450 * symlinks can be created based on udev
1451 * rules.
1452 */
1453 kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1454 }
1455 break;
1456 }
1457 }
1458
1459 static void control_work_handler(struct work_struct *work)
1460 {
1461 struct ports_device *portdev;
1462 struct virtqueue *vq;
1463 struct port_buffer *buf;
1464 unsigned int len;
1465
1466 portdev = container_of(work, struct ports_device, control_work);
1467 vq = portdev->c_ivq;
1468
1469 spin_lock(&portdev->cvq_lock);
1470 while ((buf = virtqueue_get_buf(vq, &len))) {
1471 spin_unlock(&portdev->cvq_lock);
1472
1473 buf->len = len;
1474 buf->offset = 0;
1475
1476 handle_control_message(portdev, buf);
1477
1478 spin_lock(&portdev->cvq_lock);
1479 if (add_inbuf(portdev->c_ivq, buf) < 0) {
1480 dev_warn(&portdev->vdev->dev,
1481 "Error adding buffer to queue\n");
1482 free_buf(buf);
1483 }
1484 }
1485 spin_unlock(&portdev->cvq_lock);
1486 }
1487
1488 static void out_intr(struct virtqueue *vq)
1489 {
1490 struct port *port;
1491
1492 port = find_port_by_vq(vq->vdev->priv, vq);
1493 if (!port)
1494 return;
1495
1496 wake_up_interruptible(&port->waitqueue);
1497 }
1498
1499 static void in_intr(struct virtqueue *vq)
1500 {
1501 struct port *port;
1502 unsigned long flags;
1503
1504 port = find_port_by_vq(vq->vdev->priv, vq);
1505 if (!port)
1506 return;
1507
1508 spin_lock_irqsave(&port->inbuf_lock, flags);
1509 port->inbuf = get_inbuf(port);
1510
1511 /*
1512 * Don't queue up data when port is closed. This condition
1513 * can be reached when a console port is not yet connected (no
1514 * tty is spawned) and the host sends out data to console
1515 * ports. For generic serial ports, the host won't
1516 * (shouldn't) send data till the guest is connected.
1517 */
1518 if (!port->guest_connected)
1519 discard_port_data(port);
1520
1521 spin_unlock_irqrestore(&port->inbuf_lock, flags);
1522
1523 wake_up_interruptible(&port->waitqueue);
1524
1525 /* Send a SIGIO indicating new data in case the process asked for it */
1526 send_sigio_to_port(port);
1527
1528 if (is_console_port(port) && hvc_poll(port->cons.hvc))
1529 hvc_kick();
1530 }
1531
1532 static void control_intr(struct virtqueue *vq)
1533 {
1534 struct ports_device *portdev;
1535
1536 portdev = vq->vdev->priv;
1537 schedule_work(&portdev->control_work);
1538 }
1539
1540 static void config_intr(struct virtio_device *vdev)
1541 {
1542 struct ports_device *portdev;
1543
1544 portdev = vdev->priv;
1545
1546 if (!use_multiport(portdev)) {
1547 struct port *port;
1548 u16 rows, cols;
1549
1550 vdev->config->get(vdev,
1551 offsetof(struct virtio_console_config, cols),
1552 &cols, sizeof(u16));
1553 vdev->config->get(vdev,
1554 offsetof(struct virtio_console_config, rows),
1555 &rows, sizeof(u16));
1556
1557 port = find_port_by_id(portdev, 0);
1558 set_console_size(port, rows, cols);
1559
1560 /*
1561 * We'll use this way of resizing only for legacy
1562 * support. For newer userspace
1563 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1564 * to indicate console size changes so that it can be
1565 * done per-port.
1566 */
1567 resize_console(port);
1568 }
1569 }
1570
1571 static int init_vqs(struct ports_device *portdev)
1572 {
1573 vq_callback_t **io_callbacks;
1574 char **io_names;
1575 struct virtqueue **vqs;
1576 u32 i, j, nr_ports, nr_queues;
1577 int err;
1578
1579 nr_ports = portdev->config.max_nr_ports;
1580 nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1581
1582 vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1583 io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1584 io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1585 portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1586 GFP_KERNEL);
1587 portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1588 GFP_KERNEL);
1589 if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1590 !portdev->out_vqs) {
1591 err = -ENOMEM;
1592 goto free;
1593 }
1594
1595 /*
1596 * For backward compat (newer host but older guest), the host
1597 * spawns a console port first and also inits the vqs for port
1598 * 0 before others.
1599 */
1600 j = 0;
1601 io_callbacks[j] = in_intr;
1602 io_callbacks[j + 1] = out_intr;
1603 io_names[j] = "input";
1604 io_names[j + 1] = "output";
1605 j += 2;
1606
1607 if (use_multiport(portdev)) {
1608 io_callbacks[j] = control_intr;
1609 io_callbacks[j + 1] = NULL;
1610 io_names[j] = "control-i";
1611 io_names[j + 1] = "control-o";
1612
1613 for (i = 1; i < nr_ports; i++) {
1614 j += 2;
1615 io_callbacks[j] = in_intr;
1616 io_callbacks[j + 1] = out_intr;
1617 io_names[j] = "input";
1618 io_names[j + 1] = "output";
1619 }
1620 }
1621 /* Find the queues. */
1622 err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1623 io_callbacks,
1624 (const char **)io_names);
1625 if (err)
1626 goto free;
1627
1628 j = 0;
1629 portdev->in_vqs[0] = vqs[0];
1630 portdev->out_vqs[0] = vqs[1];
1631 j += 2;
1632 if (use_multiport(portdev)) {
1633 portdev->c_ivq = vqs[j];
1634 portdev->c_ovq = vqs[j + 1];
1635
1636 for (i = 1; i < nr_ports; i++) {
1637 j += 2;
1638 portdev->in_vqs[i] = vqs[j];
1639 portdev->out_vqs[i] = vqs[j + 1];
1640 }
1641 }
1642 kfree(io_names);
1643 kfree(io_callbacks);
1644 kfree(vqs);
1645
1646 return 0;
1647
1648 free:
1649 kfree(portdev->out_vqs);
1650 kfree(portdev->in_vqs);
1651 kfree(io_names);
1652 kfree(io_callbacks);
1653 kfree(vqs);
1654
1655 return err;
1656 }
1657
1658 static const struct file_operations portdev_fops = {
1659 .owner = THIS_MODULE,
1660 };
1661
1662 /*
1663 * Once we're further in boot, we get probed like any other virtio
1664 * device.
1665 *
1666 * If the host also supports multiple console ports, we check the
1667 * config space to see how many ports the host has spawned. We
1668 * initialize each port found.
1669 */
1670 static int __devinit virtcons_probe(struct virtio_device *vdev)
1671 {
1672 struct ports_device *portdev;
1673 int err;
1674 bool multiport;
1675 bool early = early_put_chars != NULL;
1676
1677 /* Ensure to read early_put_chars now */
1678 barrier();
1679
1680 portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1681 if (!portdev) {
1682 err = -ENOMEM;
1683 goto fail;
1684 }
1685
1686 /* Attach this portdev to this virtio_device, and vice-versa. */
1687 portdev->vdev = vdev;
1688 vdev->priv = portdev;
1689
1690 spin_lock_irq(&pdrvdata_lock);
1691 portdev->drv_index = pdrvdata.index++;
1692 spin_unlock_irq(&pdrvdata_lock);
1693
1694 portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1695 &portdev_fops);
1696 if (portdev->chr_major < 0) {
1697 dev_err(&vdev->dev,
1698 "Error %d registering chrdev for device %u\n",
1699 portdev->chr_major, portdev->drv_index);
1700 err = portdev->chr_major;
1701 goto free;
1702 }
1703
1704 multiport = false;
1705 portdev->config.max_nr_ports = 1;
1706 if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
1707 offsetof(struct virtio_console_config,
1708 max_nr_ports),
1709 &portdev->config.max_nr_ports) == 0)
1710 multiport = true;
1711
1712 err = init_vqs(portdev);
1713 if (err < 0) {
1714 dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
1715 goto free_chrdev;
1716 }
1717
1718 spin_lock_init(&portdev->ports_lock);
1719 INIT_LIST_HEAD(&portdev->ports);
1720
1721 if (multiport) {
1722 unsigned int nr_added_bufs;
1723
1724 spin_lock_init(&portdev->cvq_lock);
1725 INIT_WORK(&portdev->control_work, &control_work_handler);
1726
1727 nr_added_bufs = fill_queue(portdev->c_ivq, &portdev->cvq_lock);
1728 if (!nr_added_bufs) {
1729 dev_err(&vdev->dev,
1730 "Error allocating buffers for control queue\n");
1731 err = -ENOMEM;
1732 goto free_vqs;
1733 }
1734 } else {
1735 /*
1736 * For backward compatibility: Create a console port
1737 * if we're running on older host.
1738 */
1739 add_port(portdev, 0);
1740 }
1741
1742 spin_lock_irq(&pdrvdata_lock);
1743 list_add_tail(&portdev->list, &pdrvdata.portdevs);
1744 spin_unlock_irq(&pdrvdata_lock);
1745
1746 __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1747 VIRTIO_CONSOLE_DEVICE_READY, 1);
1748
1749 /*
1750 * If there was an early virtio console, assume that there are no
1751 * other consoles. We need to wait until the hvc_alloc matches the
1752 * hvc_instantiate, otherwise tty_open will complain, resulting in
1753 * a "Warning: unable to open an initial console" boot failure.
1754 * Without multiport this is done in add_port above. With multiport
1755 * this might take some host<->guest communication - thus we have to
1756 * wait.
1757 */
1758 if (multiport && early)
1759 wait_for_completion(&early_console_added);
1760
1761 return 0;
1762
1763 free_vqs:
1764 /* The host might want to notify mgmt sw about device add failure */
1765 __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1766 VIRTIO_CONSOLE_DEVICE_READY, 0);
1767 vdev->config->del_vqs(vdev);
1768 kfree(portdev->in_vqs);
1769 kfree(portdev->out_vqs);
1770 free_chrdev:
1771 unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1772 free:
1773 kfree(portdev);
1774 fail:
1775 return err;
1776 }
1777
1778 static void virtcons_remove(struct virtio_device *vdev)
1779 {
1780 struct ports_device *portdev;
1781 struct port *port, *port2;
1782
1783 portdev = vdev->priv;
1784
1785 spin_lock_irq(&pdrvdata_lock);
1786 list_del(&portdev->list);
1787 spin_unlock_irq(&pdrvdata_lock);
1788
1789 /* Disable interrupts for vqs */
1790 vdev->config->reset(vdev);
1791 /* Finish up work that's lined up */
1792 cancel_work_sync(&portdev->control_work);
1793
1794 list_for_each_entry_safe(port, port2, &portdev->ports, list)
1795 unplug_port(port);
1796
1797 unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1798
1799 /*
1800 * When yanking out a device, we immediately lose the
1801 * (device-side) queues. So there's no point in keeping the
1802 * guest side around till we drop our final reference. This
1803 * also means that any ports which are in an open state will
1804 * have to just stop using the port, as the vqs are going
1805 * away.
1806 */
1807 if (use_multiport(portdev)) {
1808 struct port_buffer *buf;
1809 unsigned int len;
1810
1811 while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1812 free_buf(buf);
1813
1814 while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1815 free_buf(buf);
1816 }
1817
1818 vdev->config->del_vqs(vdev);
1819 kfree(portdev->in_vqs);
1820 kfree(portdev->out_vqs);
1821
1822 kfree(portdev);
1823 }
1824
1825 static struct virtio_device_id id_table[] = {
1826 { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
1827 { 0 },
1828 };
1829
1830 static unsigned int features[] = {
1831 VIRTIO_CONSOLE_F_SIZE,
1832 VIRTIO_CONSOLE_F_MULTIPORT,
1833 };
1834
1835 static struct virtio_driver virtio_console = {
1836 .feature_table = features,
1837 .feature_table_size = ARRAY_SIZE(features),
1838 .driver.name = KBUILD_MODNAME,
1839 .driver.owner = THIS_MODULE,
1840 .id_table = id_table,
1841 .probe = virtcons_probe,
1842 .remove = virtcons_remove,
1843 .config_changed = config_intr,
1844 };
1845
1846 static int __init init(void)
1847 {
1848 int err;
1849
1850 pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
1851 if (IS_ERR(pdrvdata.class)) {
1852 err = PTR_ERR(pdrvdata.class);
1853 pr_err("Error %d creating virtio-ports class\n", err);
1854 return err;
1855 }
1856
1857 pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
1858 if (!pdrvdata.debugfs_dir) {
1859 pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
1860 PTR_ERR(pdrvdata.debugfs_dir));
1861 }
1862 INIT_LIST_HEAD(&pdrvdata.consoles);
1863 INIT_LIST_HEAD(&pdrvdata.portdevs);
1864
1865 return register_virtio_driver(&virtio_console);
1866 }
1867
1868 static void __exit fini(void)
1869 {
1870 unregister_virtio_driver(&virtio_console);
1871
1872 class_destroy(pdrvdata.class);
1873 if (pdrvdata.debugfs_dir)
1874 debugfs_remove_recursive(pdrvdata.debugfs_dir);
1875 }
1876 module_init(init);
1877 module_exit(fini);
1878
1879 MODULE_DEVICE_TABLE(virtio, id_table);
1880 MODULE_DESCRIPTION("Virtio console driver");
1881 MODULE_LICENSE("GPL");