x86/speculation/mds: Fix documentation typo
[linux/fpc-iii.git] / drivers / char / virtio_console.c
bloba089474cb046af5d8dba1e7e5e855a566c2144ba
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>
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.
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.
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
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/splice.h>
28 #include <linux/pagemap.h>
29 #include <linux/init.h>
30 #include <linux/list.h>
31 #include <linux/poll.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/spinlock.h>
35 #include <linux/virtio.h>
36 #include <linux/virtio_console.h>
37 #include <linux/wait.h>
38 #include <linux/workqueue.h>
39 #include <linux/module.h>
40 #include <linux/dma-mapping.h>
41 #include "../tty/hvc/hvc_console.h"
43 #define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
46 * This is a global struct for storing common data for all the devices
47 * this driver handles.
49 * Mainly, it has a linked list for all the consoles in one place so
50 * that callbacks from hvc for get_chars(), put_chars() work properly
51 * across multiple devices and multiple ports per device.
53 struct ports_driver_data {
54 /* Used for registering chardevs */
55 struct class *class;
57 /* Used for exporting per-port information to debugfs */
58 struct dentry *debugfs_dir;
60 /* List of all the devices we're handling */
61 struct list_head portdevs;
64 * This is used to keep track of the number of hvc consoles
65 * spawned by this driver. This number is given as the first
66 * argument to hvc_alloc(). To correctly map an initial
67 * console spawned via hvc_instantiate to the console being
68 * hooked up via hvc_alloc, we need to pass the same vtermno.
70 * We also just assume the first console being initialised was
71 * the first one that got used as the initial console.
73 unsigned int next_vtermno;
75 /* All the console devices handled by this driver */
76 struct list_head consoles;
78 static struct ports_driver_data pdrvdata;
80 static DEFINE_SPINLOCK(pdrvdata_lock);
81 static DECLARE_COMPLETION(early_console_added);
83 /* This struct holds information that's relevant only for console ports */
84 struct console {
85 /* We'll place all consoles in a list in the pdrvdata struct */
86 struct list_head list;
88 /* The hvc device associated with this console port */
89 struct hvc_struct *hvc;
91 /* The size of the console */
92 struct winsize ws;
95 * This number identifies the number that we used to register
96 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
97 * number passed on by the hvc callbacks to us to
98 * differentiate between the other console ports handled by
99 * this driver
101 u32 vtermno;
104 struct port_buffer {
105 char *buf;
107 /* size of the buffer in *buf above */
108 size_t size;
110 /* used length of the buffer */
111 size_t len;
112 /* offset in the buf from which to consume data */
113 size_t offset;
115 /* DMA address of buffer */
116 dma_addr_t dma;
118 /* Device we got DMA memory from */
119 struct device *dev;
121 /* List of pending dma buffers to free */
122 struct list_head list;
124 /* If sgpages == 0 then buf is used */
125 unsigned int sgpages;
127 /* sg is used if spages > 0. sg must be the last in is struct */
128 struct scatterlist sg[0];
132 * This is a per-device struct that stores data common to all the
133 * ports for that device (vdev->priv).
135 struct ports_device {
136 /* Next portdev in the list, head is in the pdrvdata struct */
137 struct list_head list;
140 * Workqueue handlers where we process deferred work after
141 * notification
143 struct work_struct control_work;
144 struct work_struct config_work;
146 struct list_head ports;
148 /* To protect the list of ports */
149 spinlock_t ports_lock;
151 /* To protect the vq operations for the control channel */
152 spinlock_t c_ivq_lock;
153 spinlock_t c_ovq_lock;
155 /* max. number of ports this device can hold */
156 u32 max_nr_ports;
158 /* The virtio device we're associated with */
159 struct virtio_device *vdev;
162 * A couple of virtqueues for the control channel: one for
163 * guest->host transfers, one for host->guest transfers
165 struct virtqueue *c_ivq, *c_ovq;
168 * A control packet buffer for guest->host requests, protected
169 * by c_ovq_lock.
171 struct virtio_console_control cpkt;
173 /* Array of per-port IO virtqueues */
174 struct virtqueue **in_vqs, **out_vqs;
176 /* Major number for this device. Ports will be created as minors. */
177 int chr_major;
180 struct port_stats {
181 unsigned long bytes_sent, bytes_received, bytes_discarded;
184 /* This struct holds the per-port data */
185 struct port {
186 /* Next port in the list, head is in the ports_device */
187 struct list_head list;
189 /* Pointer to the parent virtio_console device */
190 struct ports_device *portdev;
192 /* The current buffer from which data has to be fed to readers */
193 struct port_buffer *inbuf;
196 * To protect the operations on the in_vq associated with this
197 * port. Has to be a spinlock because it can be called from
198 * interrupt context (get_char()).
200 spinlock_t inbuf_lock;
202 /* Protect the operations on the out_vq. */
203 spinlock_t outvq_lock;
205 /* The IO vqs for this port */
206 struct virtqueue *in_vq, *out_vq;
208 /* File in the debugfs directory that exposes this port's information */
209 struct dentry *debugfs_file;
212 * Keep count of the bytes sent, received and discarded for
213 * this port for accounting and debugging purposes. These
214 * counts are not reset across port open / close events.
216 struct port_stats stats;
219 * The entries in this struct will be valid if this port is
220 * hooked up to an hvc console
222 struct console cons;
224 /* Each port associates with a separate char device */
225 struct cdev *cdev;
226 struct device *dev;
228 /* Reference-counting to handle port hot-unplugs and file operations */
229 struct kref kref;
231 /* A waitqueue for poll() or blocking read operations */
232 wait_queue_head_t waitqueue;
234 /* The 'name' of the port that we expose via sysfs properties */
235 char *name;
237 /* We can notify apps of host connect / disconnect events via SIGIO */
238 struct fasync_struct *async_queue;
240 /* The 'id' to identify the port with the Host */
241 u32 id;
243 bool outvq_full;
245 /* Is the host device open */
246 bool host_connected;
248 /* We should allow only one process to open a port */
249 bool guest_connected;
252 /* This is the very early arch-specified put chars function. */
253 static int (*early_put_chars)(u32, const char *, int);
255 static struct port *find_port_by_vtermno(u32 vtermno)
257 struct port *port;
258 struct console *cons;
259 unsigned long flags;
261 spin_lock_irqsave(&pdrvdata_lock, flags);
262 list_for_each_entry(cons, &pdrvdata.consoles, list) {
263 if (cons->vtermno == vtermno) {
264 port = container_of(cons, struct port, cons);
265 goto out;
268 port = NULL;
269 out:
270 spin_unlock_irqrestore(&pdrvdata_lock, flags);
271 return port;
274 static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
275 dev_t dev)
277 struct port *port;
278 unsigned long flags;
280 spin_lock_irqsave(&portdev->ports_lock, flags);
281 list_for_each_entry(port, &portdev->ports, list) {
282 if (port->cdev->dev == dev) {
283 kref_get(&port->kref);
284 goto out;
287 port = NULL;
288 out:
289 spin_unlock_irqrestore(&portdev->ports_lock, flags);
291 return port;
294 static struct port *find_port_by_devt(dev_t dev)
296 struct ports_device *portdev;
297 struct port *port;
298 unsigned long flags;
300 spin_lock_irqsave(&pdrvdata_lock, flags);
301 list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
302 port = find_port_by_devt_in_portdev(portdev, dev);
303 if (port)
304 goto out;
306 port = NULL;
307 out:
308 spin_unlock_irqrestore(&pdrvdata_lock, flags);
309 return port;
312 static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
314 struct port *port;
315 unsigned long flags;
317 spin_lock_irqsave(&portdev->ports_lock, flags);
318 list_for_each_entry(port, &portdev->ports, list)
319 if (port->id == id)
320 goto out;
321 port = NULL;
322 out:
323 spin_unlock_irqrestore(&portdev->ports_lock, flags);
325 return port;
328 static struct port *find_port_by_vq(struct ports_device *portdev,
329 struct virtqueue *vq)
331 struct port *port;
332 unsigned long flags;
334 spin_lock_irqsave(&portdev->ports_lock, flags);
335 list_for_each_entry(port, &portdev->ports, list)
336 if (port->in_vq == vq || port->out_vq == vq)
337 goto out;
338 port = NULL;
339 out:
340 spin_unlock_irqrestore(&portdev->ports_lock, flags);
341 return port;
344 static bool is_console_port(struct port *port)
346 if (port->cons.hvc)
347 return true;
348 return false;
351 static bool is_rproc_serial(const struct virtio_device *vdev)
353 return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
356 static inline bool use_multiport(struct ports_device *portdev)
359 * This condition can be true when put_chars is called from
360 * early_init
362 if (!portdev->vdev)
363 return false;
364 return __virtio_test_bit(portdev->vdev, VIRTIO_CONSOLE_F_MULTIPORT);
367 static DEFINE_SPINLOCK(dma_bufs_lock);
368 static LIST_HEAD(pending_free_dma_bufs);
370 static void free_buf(struct port_buffer *buf, bool can_sleep)
372 unsigned int i;
374 for (i = 0; i < buf->sgpages; i++) {
375 struct page *page = sg_page(&buf->sg[i]);
376 if (!page)
377 break;
378 put_page(page);
381 if (!buf->dev) {
382 kfree(buf->buf);
383 } else if (is_rproc_enabled) {
384 unsigned long flags;
386 /* dma_free_coherent requires interrupts to be enabled. */
387 if (!can_sleep) {
388 /* queue up dma-buffers to be freed later */
389 spin_lock_irqsave(&dma_bufs_lock, flags);
390 list_add_tail(&buf->list, &pending_free_dma_bufs);
391 spin_unlock_irqrestore(&dma_bufs_lock, flags);
392 return;
394 dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
396 /* Release device refcnt and allow it to be freed */
397 put_device(buf->dev);
400 kfree(buf);
403 static void reclaim_dma_bufs(void)
405 unsigned long flags;
406 struct port_buffer *buf, *tmp;
407 LIST_HEAD(tmp_list);
409 if (list_empty(&pending_free_dma_bufs))
410 return;
412 /* Create a copy of the pending_free_dma_bufs while holding the lock */
413 spin_lock_irqsave(&dma_bufs_lock, flags);
414 list_cut_position(&tmp_list, &pending_free_dma_bufs,
415 pending_free_dma_bufs.prev);
416 spin_unlock_irqrestore(&dma_bufs_lock, flags);
418 /* Release the dma buffers, without irqs enabled */
419 list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
420 list_del(&buf->list);
421 free_buf(buf, true);
425 static struct port_buffer *alloc_buf(struct virtio_device *vdev, size_t buf_size,
426 int pages)
428 struct port_buffer *buf;
430 reclaim_dma_bufs();
433 * Allocate buffer and the sg list. The sg list array is allocated
434 * directly after the port_buffer struct.
436 buf = kmalloc(sizeof(*buf) + sizeof(struct scatterlist) * pages,
437 GFP_KERNEL);
438 if (!buf)
439 goto fail;
441 buf->sgpages = pages;
442 if (pages > 0) {
443 buf->dev = NULL;
444 buf->buf = NULL;
445 return buf;
448 if (is_rproc_serial(vdev)) {
450 * Allocate DMA memory from ancestor. When a virtio
451 * device is created by remoteproc, the DMA memory is
452 * associated with the grandparent device:
453 * vdev => rproc => platform-dev.
455 if (!vdev->dev.parent || !vdev->dev.parent->parent)
456 goto free_buf;
457 buf->dev = vdev->dev.parent->parent;
459 /* Increase device refcnt to avoid freeing it */
460 get_device(buf->dev);
461 buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
462 GFP_KERNEL);
463 } else {
464 buf->dev = NULL;
465 buf->buf = kmalloc(buf_size, GFP_KERNEL);
468 if (!buf->buf)
469 goto free_buf;
470 buf->len = 0;
471 buf->offset = 0;
472 buf->size = buf_size;
473 return buf;
475 free_buf:
476 kfree(buf);
477 fail:
478 return NULL;
481 /* Callers should take appropriate locks */
482 static struct port_buffer *get_inbuf(struct port *port)
484 struct port_buffer *buf;
485 unsigned int len;
487 if (port->inbuf)
488 return port->inbuf;
490 buf = virtqueue_get_buf(port->in_vq, &len);
491 if (buf) {
492 buf->len = len;
493 buf->offset = 0;
494 port->stats.bytes_received += len;
496 return buf;
500 * Create a scatter-gather list representing our input buffer and put
501 * it in the queue.
503 * Callers should take appropriate locks.
505 static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
507 struct scatterlist sg[1];
508 int ret;
510 sg_init_one(sg, buf->buf, buf->size);
512 ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC);
513 virtqueue_kick(vq);
514 if (!ret)
515 ret = vq->num_free;
516 return ret;
519 /* Discard any unread data this port has. Callers lockers. */
520 static void discard_port_data(struct port *port)
522 struct port_buffer *buf;
523 unsigned int err;
525 if (!port->portdev) {
526 /* Device has been unplugged. vqs are already gone. */
527 return;
529 buf = get_inbuf(port);
531 err = 0;
532 while (buf) {
533 port->stats.bytes_discarded += buf->len - buf->offset;
534 if (add_inbuf(port->in_vq, buf) < 0) {
535 err++;
536 free_buf(buf, false);
538 port->inbuf = NULL;
539 buf = get_inbuf(port);
541 if (err)
542 dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
543 err);
546 static bool port_has_data(struct port *port)
548 unsigned long flags;
549 bool ret;
551 ret = false;
552 spin_lock_irqsave(&port->inbuf_lock, flags);
553 port->inbuf = get_inbuf(port);
554 if (port->inbuf)
555 ret = true;
557 spin_unlock_irqrestore(&port->inbuf_lock, flags);
558 return ret;
561 static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
562 unsigned int event, unsigned int value)
564 struct scatterlist sg[1];
565 struct virtqueue *vq;
566 unsigned int len;
568 if (!use_multiport(portdev))
569 return 0;
571 vq = portdev->c_ovq;
573 spin_lock(&portdev->c_ovq_lock);
575 portdev->cpkt.id = cpu_to_virtio32(portdev->vdev, port_id);
576 portdev->cpkt.event = cpu_to_virtio16(portdev->vdev, event);
577 portdev->cpkt.value = cpu_to_virtio16(portdev->vdev, value);
579 sg_init_one(sg, &portdev->cpkt, sizeof(struct virtio_console_control));
581 if (virtqueue_add_outbuf(vq, sg, 1, &portdev->cpkt, GFP_ATOMIC) == 0) {
582 virtqueue_kick(vq);
583 while (!virtqueue_get_buf(vq, &len)
584 && !virtqueue_is_broken(vq))
585 cpu_relax();
588 spin_unlock(&portdev->c_ovq_lock);
589 return 0;
592 static ssize_t send_control_msg(struct port *port, unsigned int event,
593 unsigned int value)
595 /* Did the port get unplugged before userspace closed it? */
596 if (port->portdev)
597 return __send_control_msg(port->portdev, port->id, event, value);
598 return 0;
602 /* Callers must take the port->outvq_lock */
603 static void reclaim_consumed_buffers(struct port *port)
605 struct port_buffer *buf;
606 unsigned int len;
608 if (!port->portdev) {
609 /* Device has been unplugged. vqs are already gone. */
610 return;
612 while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
613 free_buf(buf, false);
614 port->outvq_full = false;
618 static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
619 int nents, size_t in_count,
620 void *data, bool nonblock)
622 struct virtqueue *out_vq;
623 int err;
624 unsigned long flags;
625 unsigned int len;
627 out_vq = port->out_vq;
629 spin_lock_irqsave(&port->outvq_lock, flags);
631 reclaim_consumed_buffers(port);
633 err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
635 /* Tell Host to go! */
636 virtqueue_kick(out_vq);
638 if (err) {
639 in_count = 0;
640 goto done;
643 if (out_vq->num_free == 0)
644 port->outvq_full = true;
646 if (nonblock)
647 goto done;
650 * Wait till the host acknowledges it pushed out the data we
651 * sent. This is done for data from the hvc_console; the tty
652 * operations are performed with spinlocks held so we can't
653 * sleep here. An alternative would be to copy the data to a
654 * buffer and relax the spinning requirement. The downside is
655 * we need to kmalloc a GFP_ATOMIC buffer each time the
656 * console driver writes something out.
658 while (!virtqueue_get_buf(out_vq, &len)
659 && !virtqueue_is_broken(out_vq))
660 cpu_relax();
661 done:
662 spin_unlock_irqrestore(&port->outvq_lock, flags);
664 port->stats.bytes_sent += in_count;
666 * We're expected to return the amount of data we wrote -- all
667 * of it
669 return in_count;
673 * Give out the data that's requested from the buffer that we have
674 * queued up.
676 static ssize_t fill_readbuf(struct port *port, char __user *out_buf,
677 size_t out_count, bool to_user)
679 struct port_buffer *buf;
680 unsigned long flags;
682 if (!out_count || !port_has_data(port))
683 return 0;
685 buf = port->inbuf;
686 out_count = min(out_count, buf->len - buf->offset);
688 if (to_user) {
689 ssize_t ret;
691 ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
692 if (ret)
693 return -EFAULT;
694 } else {
695 memcpy((__force char *)out_buf, buf->buf + buf->offset,
696 out_count);
699 buf->offset += out_count;
701 if (buf->offset == buf->len) {
703 * We're done using all the data in this buffer.
704 * Re-queue so that the Host can send us more data.
706 spin_lock_irqsave(&port->inbuf_lock, flags);
707 port->inbuf = NULL;
709 if (add_inbuf(port->in_vq, buf) < 0)
710 dev_warn(port->dev, "failed add_buf\n");
712 spin_unlock_irqrestore(&port->inbuf_lock, flags);
714 /* Return the number of bytes actually copied */
715 return out_count;
718 /* The condition that must be true for polling to end */
719 static bool will_read_block(struct port *port)
721 if (!port->guest_connected) {
722 /* Port got hot-unplugged. Let's exit. */
723 return false;
725 return !port_has_data(port) && port->host_connected;
728 static bool will_write_block(struct port *port)
730 bool ret;
732 if (!port->guest_connected) {
733 /* Port got hot-unplugged. Let's exit. */
734 return false;
736 if (!port->host_connected)
737 return true;
739 spin_lock_irq(&port->outvq_lock);
741 * Check if the Host has consumed any buffers since we last
742 * sent data (this is only applicable for nonblocking ports).
744 reclaim_consumed_buffers(port);
745 ret = port->outvq_full;
746 spin_unlock_irq(&port->outvq_lock);
748 return ret;
751 static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
752 size_t count, loff_t *offp)
754 struct port *port;
755 ssize_t ret;
757 port = filp->private_data;
759 /* Port is hot-unplugged. */
760 if (!port->guest_connected)
761 return -ENODEV;
763 if (!port_has_data(port)) {
765 * If nothing's connected on the host just return 0 in
766 * case of list_empty; this tells the userspace app
767 * that there's no connection
769 if (!port->host_connected)
770 return 0;
771 if (filp->f_flags & O_NONBLOCK)
772 return -EAGAIN;
774 ret = wait_event_freezable(port->waitqueue,
775 !will_read_block(port));
776 if (ret < 0)
777 return ret;
779 /* Port got hot-unplugged while we were waiting above. */
780 if (!port->guest_connected)
781 return -ENODEV;
783 * We could've received a disconnection message while we were
784 * waiting for more data.
786 * This check is not clubbed in the if() statement above as we
787 * might receive some data as well as the host could get
788 * disconnected after we got woken up from our wait. So we
789 * really want to give off whatever data we have and only then
790 * check for host_connected.
792 if (!port_has_data(port) && !port->host_connected)
793 return 0;
795 return fill_readbuf(port, ubuf, count, true);
798 static int wait_port_writable(struct port *port, bool nonblock)
800 int ret;
802 if (will_write_block(port)) {
803 if (nonblock)
804 return -EAGAIN;
806 ret = wait_event_freezable(port->waitqueue,
807 !will_write_block(port));
808 if (ret < 0)
809 return ret;
811 /* Port got hot-unplugged. */
812 if (!port->guest_connected)
813 return -ENODEV;
815 return 0;
818 static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
819 size_t count, loff_t *offp)
821 struct port *port;
822 struct port_buffer *buf;
823 ssize_t ret;
824 bool nonblock;
825 struct scatterlist sg[1];
827 /* Userspace could be out to fool us */
828 if (!count)
829 return 0;
831 port = filp->private_data;
833 nonblock = filp->f_flags & O_NONBLOCK;
835 ret = wait_port_writable(port, nonblock);
836 if (ret < 0)
837 return ret;
839 count = min((size_t)(32 * 1024), count);
841 buf = alloc_buf(port->portdev->vdev, count, 0);
842 if (!buf)
843 return -ENOMEM;
845 ret = copy_from_user(buf->buf, ubuf, count);
846 if (ret) {
847 ret = -EFAULT;
848 goto free_buf;
852 * We now ask send_buf() to not spin for generic ports -- we
853 * can re-use the same code path that non-blocking file
854 * descriptors take for blocking file descriptors since the
855 * wait is already done and we're certain the write will go
856 * through to the host.
858 nonblock = true;
859 sg_init_one(sg, buf->buf, count);
860 ret = __send_to_port(port, sg, 1, count, buf, nonblock);
862 if (nonblock && ret > 0)
863 goto out;
865 free_buf:
866 free_buf(buf, true);
867 out:
868 return ret;
871 struct sg_list {
872 unsigned int n;
873 unsigned int size;
874 size_t len;
875 struct scatterlist *sg;
878 static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
879 struct splice_desc *sd)
881 struct sg_list *sgl = sd->u.data;
882 unsigned int offset, len;
884 if (sgl->n == sgl->size)
885 return 0;
887 /* Try lock this page */
888 if (pipe_buf_steal(pipe, buf) == 0) {
889 /* Get reference and unlock page for moving */
890 get_page(buf->page);
891 unlock_page(buf->page);
893 len = min(buf->len, sd->len);
894 sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
895 } else {
896 /* Failback to copying a page */
897 struct page *page = alloc_page(GFP_KERNEL);
898 char *src;
900 if (!page)
901 return -ENOMEM;
903 offset = sd->pos & ~PAGE_MASK;
905 len = sd->len;
906 if (len + offset > PAGE_SIZE)
907 len = PAGE_SIZE - offset;
909 src = kmap_atomic(buf->page);
910 memcpy(page_address(page) + offset, src + buf->offset, len);
911 kunmap_atomic(src);
913 sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
915 sgl->n++;
916 sgl->len += len;
918 return len;
921 /* Faster zero-copy write by splicing */
922 static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
923 struct file *filp, loff_t *ppos,
924 size_t len, unsigned int flags)
926 struct port *port = filp->private_data;
927 struct sg_list sgl;
928 ssize_t ret;
929 struct port_buffer *buf;
930 struct splice_desc sd = {
931 .total_len = len,
932 .flags = flags,
933 .pos = *ppos,
934 .u.data = &sgl,
938 * Rproc_serial does not yet support splice. To support splice
939 * pipe_to_sg() must allocate dma-buffers and copy content from
940 * regular pages to dma pages. And alloc_buf and free_buf must
941 * support allocating and freeing such a list of dma-buffers.
943 if (is_rproc_serial(port->out_vq->vdev))
944 return -EINVAL;
947 * pipe->nrbufs == 0 means there are no data to transfer,
948 * so this returns just 0 for no data.
950 pipe_lock(pipe);
951 if (!pipe->nrbufs) {
952 ret = 0;
953 goto error_out;
956 ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
957 if (ret < 0)
958 goto error_out;
960 buf = alloc_buf(port->portdev->vdev, 0, pipe->nrbufs);
961 if (!buf) {
962 ret = -ENOMEM;
963 goto error_out;
966 sgl.n = 0;
967 sgl.len = 0;
968 sgl.size = pipe->nrbufs;
969 sgl.sg = buf->sg;
970 sg_init_table(sgl.sg, sgl.size);
971 ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
972 pipe_unlock(pipe);
973 if (likely(ret > 0))
974 ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
976 if (unlikely(ret <= 0))
977 free_buf(buf, true);
978 return ret;
980 error_out:
981 pipe_unlock(pipe);
982 return ret;
985 static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
987 struct port *port;
988 unsigned int ret;
990 port = filp->private_data;
991 poll_wait(filp, &port->waitqueue, wait);
993 if (!port->guest_connected) {
994 /* Port got unplugged */
995 return POLLHUP;
997 ret = 0;
998 if (!will_read_block(port))
999 ret |= POLLIN | POLLRDNORM;
1000 if (!will_write_block(port))
1001 ret |= POLLOUT;
1002 if (!port->host_connected)
1003 ret |= POLLHUP;
1005 return ret;
1008 static void remove_port(struct kref *kref);
1010 static int port_fops_release(struct inode *inode, struct file *filp)
1012 struct port *port;
1014 port = filp->private_data;
1016 /* Notify host of port being closed */
1017 send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1019 spin_lock_irq(&port->inbuf_lock);
1020 port->guest_connected = false;
1022 discard_port_data(port);
1024 spin_unlock_irq(&port->inbuf_lock);
1026 spin_lock_irq(&port->outvq_lock);
1027 reclaim_consumed_buffers(port);
1028 spin_unlock_irq(&port->outvq_lock);
1030 reclaim_dma_bufs();
1032 * Locks aren't necessary here as a port can't be opened after
1033 * unplug, and if a port isn't unplugged, a kref would already
1034 * exist for the port. Plus, taking ports_lock here would
1035 * create a dependency on other locks taken by functions
1036 * inside remove_port if we're the last holder of the port,
1037 * creating many problems.
1039 kref_put(&port->kref, remove_port);
1041 return 0;
1044 static int port_fops_open(struct inode *inode, struct file *filp)
1046 struct cdev *cdev = inode->i_cdev;
1047 struct port *port;
1048 int ret;
1050 /* We get the port with a kref here */
1051 port = find_port_by_devt(cdev->dev);
1052 if (!port) {
1053 /* Port was unplugged before we could proceed */
1054 return -ENXIO;
1056 filp->private_data = port;
1059 * Don't allow opening of console port devices -- that's done
1060 * via /dev/hvc
1062 if (is_console_port(port)) {
1063 ret = -ENXIO;
1064 goto out;
1067 /* Allow only one process to open a particular port at a time */
1068 spin_lock_irq(&port->inbuf_lock);
1069 if (port->guest_connected) {
1070 spin_unlock_irq(&port->inbuf_lock);
1071 ret = -EBUSY;
1072 goto out;
1075 port->guest_connected = true;
1076 spin_unlock_irq(&port->inbuf_lock);
1078 spin_lock_irq(&port->outvq_lock);
1080 * There might be a chance that we missed reclaiming a few
1081 * buffers in the window of the port getting previously closed
1082 * and opening now.
1084 reclaim_consumed_buffers(port);
1085 spin_unlock_irq(&port->outvq_lock);
1087 nonseekable_open(inode, filp);
1089 /* Notify host of port being opened */
1090 send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1092 return 0;
1093 out:
1094 kref_put(&port->kref, remove_port);
1095 return ret;
1098 static int port_fops_fasync(int fd, struct file *filp, int mode)
1100 struct port *port;
1102 port = filp->private_data;
1103 return fasync_helper(fd, filp, mode, &port->async_queue);
1107 * The file operations that we support: programs in the guest can open
1108 * a console device, read from it, write to it, poll for data and
1109 * close it. The devices are at
1110 * /dev/vport<device number>p<port number>
1112 static const struct file_operations port_fops = {
1113 .owner = THIS_MODULE,
1114 .open = port_fops_open,
1115 .read = port_fops_read,
1116 .write = port_fops_write,
1117 .splice_write = port_fops_splice_write,
1118 .poll = port_fops_poll,
1119 .release = port_fops_release,
1120 .fasync = port_fops_fasync,
1121 .llseek = no_llseek,
1125 * The put_chars() callback is pretty straightforward.
1127 * We turn the characters into a scatter-gather list, add it to the
1128 * output queue and then kick the Host. Then we sit here waiting for
1129 * it to finish: inefficient in theory, but in practice
1130 * implementations will do it immediately.
1132 static int put_chars(u32 vtermno, const char *buf, int count)
1134 struct port *port;
1135 struct scatterlist sg[1];
1136 void *data;
1137 int ret;
1139 if (unlikely(early_put_chars))
1140 return early_put_chars(vtermno, buf, count);
1142 port = find_port_by_vtermno(vtermno);
1143 if (!port)
1144 return -EPIPE;
1146 data = kmemdup(buf, count, GFP_ATOMIC);
1147 if (!data)
1148 return -ENOMEM;
1150 sg_init_one(sg, data, count);
1151 ret = __send_to_port(port, sg, 1, count, data, false);
1152 kfree(data);
1153 return ret;
1157 * get_chars() is the callback from the hvc_console infrastructure
1158 * when an interrupt is received.
1160 * We call out to fill_readbuf that gets us the required data from the
1161 * buffers that are queued up.
1163 static int get_chars(u32 vtermno, char *buf, int count)
1165 struct port *port;
1167 /* If we've not set up the port yet, we have no input to give. */
1168 if (unlikely(early_put_chars))
1169 return 0;
1171 port = find_port_by_vtermno(vtermno);
1172 if (!port)
1173 return -EPIPE;
1175 /* If we don't have an input queue yet, we can't get input. */
1176 BUG_ON(!port->in_vq);
1178 return fill_readbuf(port, (__force char __user *)buf, count, false);
1181 static void resize_console(struct port *port)
1183 struct virtio_device *vdev;
1185 /* The port could have been hot-unplugged */
1186 if (!port || !is_console_port(port))
1187 return;
1189 vdev = port->portdev->vdev;
1191 /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1192 if (!is_rproc_serial(vdev) &&
1193 virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1194 hvc_resize(port->cons.hvc, port->cons.ws);
1197 /* We set the configuration at this point, since we now have a tty */
1198 static int notifier_add_vio(struct hvc_struct *hp, int data)
1200 struct port *port;
1202 port = find_port_by_vtermno(hp->vtermno);
1203 if (!port)
1204 return -EINVAL;
1206 hp->irq_requested = 1;
1207 resize_console(port);
1209 return 0;
1212 static void notifier_del_vio(struct hvc_struct *hp, int data)
1214 hp->irq_requested = 0;
1217 /* The operations for console ports. */
1218 static const struct hv_ops hv_ops = {
1219 .get_chars = get_chars,
1220 .put_chars = put_chars,
1221 .notifier_add = notifier_add_vio,
1222 .notifier_del = notifier_del_vio,
1223 .notifier_hangup = notifier_del_vio,
1227 * Console drivers are initialized very early so boot messages can go
1228 * out, so we do things slightly differently from the generic virtio
1229 * initialization of the net and block drivers.
1231 * At this stage, the console is output-only. It's too early to set
1232 * up a virtqueue, so we let the drivers do some boutique early-output
1233 * thing.
1235 int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
1237 early_put_chars = put_chars;
1238 return hvc_instantiate(0, 0, &hv_ops);
1241 static int init_port_console(struct port *port)
1243 int ret;
1246 * The Host's telling us this port is a console port. Hook it
1247 * up with an hvc console.
1249 * To set up and manage our virtual console, we call
1250 * hvc_alloc().
1252 * The first argument of hvc_alloc() is the virtual console
1253 * number. The second argument is the parameter for the
1254 * notification mechanism (like irq number). We currently
1255 * leave this as zero, virtqueues have implicit notifications.
1257 * The third argument is a "struct hv_ops" containing the
1258 * put_chars() get_chars(), notifier_add() and notifier_del()
1259 * pointers. The final argument is the output buffer size: we
1260 * can do any size, so we put PAGE_SIZE here.
1262 port->cons.vtermno = pdrvdata.next_vtermno;
1264 port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1265 if (IS_ERR(port->cons.hvc)) {
1266 ret = PTR_ERR(port->cons.hvc);
1267 dev_err(port->dev,
1268 "error %d allocating hvc for port\n", ret);
1269 port->cons.hvc = NULL;
1270 return ret;
1272 spin_lock_irq(&pdrvdata_lock);
1273 pdrvdata.next_vtermno++;
1274 list_add_tail(&port->cons.list, &pdrvdata.consoles);
1275 spin_unlock_irq(&pdrvdata_lock);
1276 port->guest_connected = true;
1279 * Start using the new console output if this is the first
1280 * console to come up.
1282 if (early_put_chars)
1283 early_put_chars = NULL;
1285 /* Notify host of port being opened */
1286 send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1288 return 0;
1291 static ssize_t show_port_name(struct device *dev,
1292 struct device_attribute *attr, char *buffer)
1294 struct port *port;
1296 port = dev_get_drvdata(dev);
1298 return sprintf(buffer, "%s\n", port->name);
1301 static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1303 static struct attribute *port_sysfs_entries[] = {
1304 &dev_attr_name.attr,
1305 NULL
1308 static const struct attribute_group port_attribute_group = {
1309 .name = NULL, /* put in device directory */
1310 .attrs = port_sysfs_entries,
1313 static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1314 size_t count, loff_t *offp)
1316 struct port *port;
1317 char *buf;
1318 ssize_t ret, out_offset, out_count;
1320 out_count = 1024;
1321 buf = kmalloc(out_count, GFP_KERNEL);
1322 if (!buf)
1323 return -ENOMEM;
1325 port = filp->private_data;
1326 out_offset = 0;
1327 out_offset += snprintf(buf + out_offset, out_count,
1328 "name: %s\n", port->name ? port->name : "");
1329 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1330 "guest_connected: %d\n", port->guest_connected);
1331 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1332 "host_connected: %d\n", port->host_connected);
1333 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1334 "outvq_full: %d\n", port->outvq_full);
1335 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1336 "bytes_sent: %lu\n", port->stats.bytes_sent);
1337 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1338 "bytes_received: %lu\n",
1339 port->stats.bytes_received);
1340 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1341 "bytes_discarded: %lu\n",
1342 port->stats.bytes_discarded);
1343 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1344 "is_console: %s\n",
1345 is_console_port(port) ? "yes" : "no");
1346 out_offset += snprintf(buf + out_offset, out_count - out_offset,
1347 "console_vtermno: %u\n", port->cons.vtermno);
1349 ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1350 kfree(buf);
1351 return ret;
1354 static const struct file_operations port_debugfs_ops = {
1355 .owner = THIS_MODULE,
1356 .open = simple_open,
1357 .read = debugfs_read,
1360 static void set_console_size(struct port *port, u16 rows, u16 cols)
1362 if (!port || !is_console_port(port))
1363 return;
1365 port->cons.ws.ws_row = rows;
1366 port->cons.ws.ws_col = cols;
1369 static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1371 struct port_buffer *buf;
1372 unsigned int nr_added_bufs;
1373 int ret;
1375 nr_added_bufs = 0;
1376 do {
1377 buf = alloc_buf(vq->vdev, PAGE_SIZE, 0);
1378 if (!buf)
1379 break;
1381 spin_lock_irq(lock);
1382 ret = add_inbuf(vq, buf);
1383 if (ret < 0) {
1384 spin_unlock_irq(lock);
1385 free_buf(buf, true);
1386 break;
1388 nr_added_bufs++;
1389 spin_unlock_irq(lock);
1390 } while (ret > 0);
1392 return nr_added_bufs;
1395 static void send_sigio_to_port(struct port *port)
1397 if (port->async_queue && port->guest_connected)
1398 kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1401 static int add_port(struct ports_device *portdev, u32 id)
1403 char debugfs_name[16];
1404 struct port *port;
1405 dev_t devt;
1406 unsigned int nr_added_bufs;
1407 int err;
1409 port = kmalloc(sizeof(*port), GFP_KERNEL);
1410 if (!port) {
1411 err = -ENOMEM;
1412 goto fail;
1414 kref_init(&port->kref);
1416 port->portdev = portdev;
1417 port->id = id;
1419 port->name = NULL;
1420 port->inbuf = NULL;
1421 port->cons.hvc = NULL;
1422 port->async_queue = NULL;
1424 port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1426 port->host_connected = port->guest_connected = false;
1427 port->stats = (struct port_stats) { 0 };
1429 port->outvq_full = false;
1431 port->in_vq = portdev->in_vqs[port->id];
1432 port->out_vq = portdev->out_vqs[port->id];
1434 port->cdev = cdev_alloc();
1435 if (!port->cdev) {
1436 dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1437 err = -ENOMEM;
1438 goto free_port;
1440 port->cdev->ops = &port_fops;
1442 devt = MKDEV(portdev->chr_major, id);
1443 err = cdev_add(port->cdev, devt, 1);
1444 if (err < 0) {
1445 dev_err(&port->portdev->vdev->dev,
1446 "Error %d adding cdev for port %u\n", err, id);
1447 goto free_cdev;
1449 port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1450 devt, port, "vport%up%u",
1451 port->portdev->vdev->index, id);
1452 if (IS_ERR(port->dev)) {
1453 err = PTR_ERR(port->dev);
1454 dev_err(&port->portdev->vdev->dev,
1455 "Error %d creating device for port %u\n",
1456 err, id);
1457 goto free_cdev;
1460 spin_lock_init(&port->inbuf_lock);
1461 spin_lock_init(&port->outvq_lock);
1462 init_waitqueue_head(&port->waitqueue);
1464 /* Fill the in_vq with buffers so the host can send us data. */
1465 nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1466 if (!nr_added_bufs) {
1467 dev_err(port->dev, "Error allocating inbufs\n");
1468 err = -ENOMEM;
1469 goto free_device;
1472 if (is_rproc_serial(port->portdev->vdev))
1474 * For rproc_serial assume remote processor is connected.
1475 * rproc_serial does not want the console port, only
1476 * the generic port implementation.
1478 port->host_connected = true;
1479 else if (!use_multiport(port->portdev)) {
1481 * If we're not using multiport support,
1482 * this has to be a console port.
1484 err = init_port_console(port);
1485 if (err)
1486 goto free_inbufs;
1489 spin_lock_irq(&portdev->ports_lock);
1490 list_add_tail(&port->list, &port->portdev->ports);
1491 spin_unlock_irq(&portdev->ports_lock);
1494 * Tell the Host we're set so that it can send us various
1495 * configuration parameters for this port (eg, port name,
1496 * caching, whether this is a console port, etc.)
1498 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1500 if (pdrvdata.debugfs_dir) {
1502 * Finally, create the debugfs file that we can use to
1503 * inspect a port's state at any time
1505 snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
1506 port->portdev->vdev->index, id);
1507 port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1508 pdrvdata.debugfs_dir,
1509 port,
1510 &port_debugfs_ops);
1512 return 0;
1514 free_inbufs:
1515 free_device:
1516 device_destroy(pdrvdata.class, port->dev->devt);
1517 free_cdev:
1518 cdev_del(port->cdev);
1519 free_port:
1520 kfree(port);
1521 fail:
1522 /* The host might want to notify management sw about port add failure */
1523 __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1524 return err;
1527 /* No users remain, remove all port-specific data. */
1528 static void remove_port(struct kref *kref)
1530 struct port *port;
1532 port = container_of(kref, struct port, kref);
1534 kfree(port);
1537 static void remove_port_data(struct port *port)
1539 spin_lock_irq(&port->inbuf_lock);
1540 /* Remove unused data this port might have received. */
1541 discard_port_data(port);
1542 spin_unlock_irq(&port->inbuf_lock);
1544 spin_lock_irq(&port->outvq_lock);
1545 reclaim_consumed_buffers(port);
1546 spin_unlock_irq(&port->outvq_lock);
1550 * Port got unplugged. Remove port from portdev's list and drop the
1551 * kref reference. If no userspace has this port opened, it will
1552 * result in immediate removal the port.
1554 static void unplug_port(struct port *port)
1556 spin_lock_irq(&port->portdev->ports_lock);
1557 list_del(&port->list);
1558 spin_unlock_irq(&port->portdev->ports_lock);
1560 spin_lock_irq(&port->inbuf_lock);
1561 if (port->guest_connected) {
1562 /* Let the app know the port is going down. */
1563 send_sigio_to_port(port);
1565 /* Do this after sigio is actually sent */
1566 port->guest_connected = false;
1567 port->host_connected = false;
1569 wake_up_interruptible(&port->waitqueue);
1571 spin_unlock_irq(&port->inbuf_lock);
1573 if (is_console_port(port)) {
1574 spin_lock_irq(&pdrvdata_lock);
1575 list_del(&port->cons.list);
1576 spin_unlock_irq(&pdrvdata_lock);
1577 hvc_remove(port->cons.hvc);
1580 remove_port_data(port);
1583 * We should just assume the device itself has gone off --
1584 * else a close on an open port later will try to send out a
1585 * control message.
1587 port->portdev = NULL;
1589 sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1590 device_destroy(pdrvdata.class, port->dev->devt);
1591 cdev_del(port->cdev);
1593 debugfs_remove(port->debugfs_file);
1594 kfree(port->name);
1597 * Locks around here are not necessary - a port can't be
1598 * opened after we removed the port struct from ports_list
1599 * above.
1601 kref_put(&port->kref, remove_port);
1604 /* Any private messages that the Host and Guest want to share */
1605 static void handle_control_message(struct virtio_device *vdev,
1606 struct ports_device *portdev,
1607 struct port_buffer *buf)
1609 struct virtio_console_control *cpkt;
1610 struct port *port;
1611 size_t name_size;
1612 int err;
1614 cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1616 port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
1617 if (!port &&
1618 cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
1619 /* No valid header at start of buffer. Drop it. */
1620 dev_dbg(&portdev->vdev->dev,
1621 "Invalid index %u in control packet\n", cpkt->id);
1622 return;
1625 switch (virtio16_to_cpu(vdev, cpkt->event)) {
1626 case VIRTIO_CONSOLE_PORT_ADD:
1627 if (port) {
1628 dev_dbg(&portdev->vdev->dev,
1629 "Port %u already added\n", port->id);
1630 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1631 break;
1633 if (virtio32_to_cpu(vdev, cpkt->id) >=
1634 portdev->max_nr_ports) {
1635 dev_warn(&portdev->vdev->dev,
1636 "Request for adding port with "
1637 "out-of-bound id %u, max. supported id: %u\n",
1638 cpkt->id, portdev->max_nr_ports - 1);
1639 break;
1641 add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
1642 break;
1643 case VIRTIO_CONSOLE_PORT_REMOVE:
1644 unplug_port(port);
1645 break;
1646 case VIRTIO_CONSOLE_CONSOLE_PORT:
1647 if (!cpkt->value)
1648 break;
1649 if (is_console_port(port))
1650 break;
1652 init_port_console(port);
1653 complete(&early_console_added);
1655 * Could remove the port here in case init fails - but
1656 * have to notify the host first.
1658 break;
1659 case VIRTIO_CONSOLE_RESIZE: {
1660 struct {
1661 __u16 rows;
1662 __u16 cols;
1663 } size;
1665 if (!is_console_port(port))
1666 break;
1668 memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1669 sizeof(size));
1670 set_console_size(port, size.rows, size.cols);
1672 port->cons.hvc->irq_requested = 1;
1673 resize_console(port);
1674 break;
1676 case VIRTIO_CONSOLE_PORT_OPEN:
1677 port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
1678 wake_up_interruptible(&port->waitqueue);
1680 * If the host port got closed and the host had any
1681 * unconsumed buffers, we'll be able to reclaim them
1682 * now.
1684 spin_lock_irq(&port->outvq_lock);
1685 reclaim_consumed_buffers(port);
1686 spin_unlock_irq(&port->outvq_lock);
1689 * If the guest is connected, it'll be interested in
1690 * knowing the host connection state changed.
1692 spin_lock_irq(&port->inbuf_lock);
1693 send_sigio_to_port(port);
1694 spin_unlock_irq(&port->inbuf_lock);
1695 break;
1696 case VIRTIO_CONSOLE_PORT_NAME:
1698 * If we woke up after hibernation, we can get this
1699 * again. Skip it in that case.
1701 if (port->name)
1702 break;
1705 * Skip the size of the header and the cpkt to get the size
1706 * of the name that was sent
1708 name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1710 port->name = kmalloc(name_size, GFP_KERNEL);
1711 if (!port->name) {
1712 dev_err(port->dev,
1713 "Not enough space to store port name\n");
1714 break;
1716 strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1717 name_size - 1);
1718 port->name[name_size - 1] = 0;
1721 * Since we only have one sysfs attribute, 'name',
1722 * create it only if we have a name for the port.
1724 err = sysfs_create_group(&port->dev->kobj,
1725 &port_attribute_group);
1726 if (err) {
1727 dev_err(port->dev,
1728 "Error %d creating sysfs device attributes\n",
1729 err);
1730 } else {
1732 * Generate a udev event so that appropriate
1733 * symlinks can be created based on udev
1734 * rules.
1736 kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1738 break;
1742 static void control_work_handler(struct work_struct *work)
1744 struct ports_device *portdev;
1745 struct virtqueue *vq;
1746 struct port_buffer *buf;
1747 unsigned int len;
1749 portdev = container_of(work, struct ports_device, control_work);
1750 vq = portdev->c_ivq;
1752 spin_lock(&portdev->c_ivq_lock);
1753 while ((buf = virtqueue_get_buf(vq, &len))) {
1754 spin_unlock(&portdev->c_ivq_lock);
1756 buf->len = len;
1757 buf->offset = 0;
1759 handle_control_message(vq->vdev, portdev, buf);
1761 spin_lock(&portdev->c_ivq_lock);
1762 if (add_inbuf(portdev->c_ivq, buf) < 0) {
1763 dev_warn(&portdev->vdev->dev,
1764 "Error adding buffer to queue\n");
1765 free_buf(buf, false);
1768 spin_unlock(&portdev->c_ivq_lock);
1771 static void flush_bufs(struct virtqueue *vq, bool can_sleep)
1773 struct port_buffer *buf;
1774 unsigned int len;
1776 while ((buf = virtqueue_get_buf(vq, &len)))
1777 free_buf(buf, can_sleep);
1780 static void out_intr(struct virtqueue *vq)
1782 struct port *port;
1784 port = find_port_by_vq(vq->vdev->priv, vq);
1785 if (!port) {
1786 flush_bufs(vq, false);
1787 return;
1790 wake_up_interruptible(&port->waitqueue);
1793 static void in_intr(struct virtqueue *vq)
1795 struct port *port;
1796 unsigned long flags;
1798 port = find_port_by_vq(vq->vdev->priv, vq);
1799 if (!port) {
1800 flush_bufs(vq, false);
1801 return;
1804 spin_lock_irqsave(&port->inbuf_lock, flags);
1805 port->inbuf = get_inbuf(port);
1808 * Normally the port should not accept data when the port is
1809 * closed. For generic serial ports, the host won't (shouldn't)
1810 * send data till the guest is connected. But this condition
1811 * can be reached when a console port is not yet connected (no
1812 * tty is spawned) and the other side sends out data over the
1813 * vring, or when a remote devices start sending data before
1814 * the ports are opened.
1816 * A generic serial port will discard data if not connected,
1817 * while console ports and rproc-serial ports accepts data at
1818 * any time. rproc-serial is initiated with guest_connected to
1819 * false because port_fops_open expects this. Console ports are
1820 * hooked up with an HVC console and is initialized with
1821 * guest_connected to true.
1824 if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1825 discard_port_data(port);
1827 /* Send a SIGIO indicating new data in case the process asked for it */
1828 send_sigio_to_port(port);
1830 spin_unlock_irqrestore(&port->inbuf_lock, flags);
1832 wake_up_interruptible(&port->waitqueue);
1834 if (is_console_port(port) && hvc_poll(port->cons.hvc))
1835 hvc_kick();
1838 static void control_intr(struct virtqueue *vq)
1840 struct ports_device *portdev;
1842 portdev = vq->vdev->priv;
1843 schedule_work(&portdev->control_work);
1846 static void config_intr(struct virtio_device *vdev)
1848 struct ports_device *portdev;
1850 portdev = vdev->priv;
1852 if (!use_multiport(portdev))
1853 schedule_work(&portdev->config_work);
1856 static void config_work_handler(struct work_struct *work)
1858 struct ports_device *portdev;
1860 portdev = container_of(work, struct ports_device, config_work);
1861 if (!use_multiport(portdev)) {
1862 struct virtio_device *vdev;
1863 struct port *port;
1864 u16 rows, cols;
1866 vdev = portdev->vdev;
1867 virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1868 virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1870 port = find_port_by_id(portdev, 0);
1871 set_console_size(port, rows, cols);
1874 * We'll use this way of resizing only for legacy
1875 * support. For newer userspace
1876 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1877 * to indicate console size changes so that it can be
1878 * done per-port.
1880 resize_console(port);
1884 static int init_vqs(struct ports_device *portdev)
1886 vq_callback_t **io_callbacks;
1887 char **io_names;
1888 struct virtqueue **vqs;
1889 u32 i, j, nr_ports, nr_queues;
1890 int err;
1892 nr_ports = portdev->max_nr_ports;
1893 nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1895 vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1896 io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1897 io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1898 portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1899 GFP_KERNEL);
1900 portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1901 GFP_KERNEL);
1902 if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1903 !portdev->out_vqs) {
1904 err = -ENOMEM;
1905 goto free;
1909 * For backward compat (newer host but older guest), the host
1910 * spawns a console port first and also inits the vqs for port
1911 * 0 before others.
1913 j = 0;
1914 io_callbacks[j] = in_intr;
1915 io_callbacks[j + 1] = out_intr;
1916 io_names[j] = "input";
1917 io_names[j + 1] = "output";
1918 j += 2;
1920 if (use_multiport(portdev)) {
1921 io_callbacks[j] = control_intr;
1922 io_callbacks[j + 1] = NULL;
1923 io_names[j] = "control-i";
1924 io_names[j + 1] = "control-o";
1926 for (i = 1; i < nr_ports; i++) {
1927 j += 2;
1928 io_callbacks[j] = in_intr;
1929 io_callbacks[j + 1] = out_intr;
1930 io_names[j] = "input";
1931 io_names[j + 1] = "output";
1934 /* Find the queues. */
1935 err = virtio_find_vqs(portdev->vdev, nr_queues, vqs,
1936 io_callbacks,
1937 (const char **)io_names, NULL);
1938 if (err)
1939 goto free;
1941 j = 0;
1942 portdev->in_vqs[0] = vqs[0];
1943 portdev->out_vqs[0] = vqs[1];
1944 j += 2;
1945 if (use_multiport(portdev)) {
1946 portdev->c_ivq = vqs[j];
1947 portdev->c_ovq = vqs[j + 1];
1949 for (i = 1; i < nr_ports; i++) {
1950 j += 2;
1951 portdev->in_vqs[i] = vqs[j];
1952 portdev->out_vqs[i] = vqs[j + 1];
1955 kfree(io_names);
1956 kfree(io_callbacks);
1957 kfree(vqs);
1959 return 0;
1961 free:
1962 kfree(portdev->out_vqs);
1963 kfree(portdev->in_vqs);
1964 kfree(io_names);
1965 kfree(io_callbacks);
1966 kfree(vqs);
1968 return err;
1971 static const struct file_operations portdev_fops = {
1972 .owner = THIS_MODULE,
1975 static void remove_vqs(struct ports_device *portdev)
1977 struct virtqueue *vq;
1979 virtio_device_for_each_vq(portdev->vdev, vq) {
1980 struct port_buffer *buf;
1982 flush_bufs(vq, true);
1983 while ((buf = virtqueue_detach_unused_buf(vq)))
1984 free_buf(buf, true);
1986 portdev->vdev->config->del_vqs(portdev->vdev);
1987 kfree(portdev->in_vqs);
1988 kfree(portdev->out_vqs);
1991 static void virtcons_remove(struct virtio_device *vdev)
1993 struct ports_device *portdev;
1994 struct port *port, *port2;
1996 portdev = vdev->priv;
1998 spin_lock_irq(&pdrvdata_lock);
1999 list_del(&portdev->list);
2000 spin_unlock_irq(&pdrvdata_lock);
2002 /* Disable interrupts for vqs */
2003 vdev->config->reset(vdev);
2004 /* Finish up work that's lined up */
2005 if (use_multiport(portdev))
2006 cancel_work_sync(&portdev->control_work);
2007 else
2008 cancel_work_sync(&portdev->config_work);
2010 list_for_each_entry_safe(port, port2, &portdev->ports, list)
2011 unplug_port(port);
2013 unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2016 * When yanking out a device, we immediately lose the
2017 * (device-side) queues. So there's no point in keeping the
2018 * guest side around till we drop our final reference. This
2019 * also means that any ports which are in an open state will
2020 * have to just stop using the port, as the vqs are going
2021 * away.
2023 remove_vqs(portdev);
2024 kfree(portdev);
2028 * Once we're further in boot, we get probed like any other virtio
2029 * device.
2031 * If the host also supports multiple console ports, we check the
2032 * config space to see how many ports the host has spawned. We
2033 * initialize each port found.
2035 static int virtcons_probe(struct virtio_device *vdev)
2037 struct ports_device *portdev;
2038 int err;
2039 bool multiport;
2040 bool early = early_put_chars != NULL;
2042 /* We only need a config space if features are offered */
2043 if (!vdev->config->get &&
2044 (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
2045 || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
2046 dev_err(&vdev->dev, "%s failure: config access disabled\n",
2047 __func__);
2048 return -EINVAL;
2051 /* Ensure to read early_put_chars now */
2052 barrier();
2054 portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
2055 if (!portdev) {
2056 err = -ENOMEM;
2057 goto fail;
2060 /* Attach this portdev to this virtio_device, and vice-versa. */
2061 portdev->vdev = vdev;
2062 vdev->priv = portdev;
2064 portdev->chr_major = register_chrdev(0, "virtio-portsdev",
2065 &portdev_fops);
2066 if (portdev->chr_major < 0) {
2067 dev_err(&vdev->dev,
2068 "Error %d registering chrdev for device %u\n",
2069 portdev->chr_major, vdev->index);
2070 err = portdev->chr_major;
2071 goto free;
2074 multiport = false;
2075 portdev->max_nr_ports = 1;
2077 /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2078 if (!is_rproc_serial(vdev) &&
2079 virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2080 struct virtio_console_config, max_nr_ports,
2081 &portdev->max_nr_ports) == 0) {
2082 multiport = true;
2085 err = init_vqs(portdev);
2086 if (err < 0) {
2087 dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2088 goto free_chrdev;
2091 spin_lock_init(&portdev->ports_lock);
2092 INIT_LIST_HEAD(&portdev->ports);
2093 INIT_LIST_HEAD(&portdev->list);
2095 virtio_device_ready(portdev->vdev);
2097 INIT_WORK(&portdev->config_work, &config_work_handler);
2098 INIT_WORK(&portdev->control_work, &control_work_handler);
2100 if (multiport) {
2101 unsigned int nr_added_bufs;
2103 spin_lock_init(&portdev->c_ivq_lock);
2104 spin_lock_init(&portdev->c_ovq_lock);
2106 nr_added_bufs = fill_queue(portdev->c_ivq,
2107 &portdev->c_ivq_lock);
2108 if (!nr_added_bufs) {
2109 dev_err(&vdev->dev,
2110 "Error allocating buffers for control queue\n");
2112 * The host might want to notify mgmt sw about device
2113 * add failure.
2115 __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2116 VIRTIO_CONSOLE_DEVICE_READY, 0);
2117 /* Device was functional: we need full cleanup. */
2118 virtcons_remove(vdev);
2119 return -ENOMEM;
2121 } else {
2123 * For backward compatibility: Create a console port
2124 * if we're running on older host.
2126 add_port(portdev, 0);
2129 spin_lock_irq(&pdrvdata_lock);
2130 list_add_tail(&portdev->list, &pdrvdata.portdevs);
2131 spin_unlock_irq(&pdrvdata_lock);
2133 __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2134 VIRTIO_CONSOLE_DEVICE_READY, 1);
2137 * If there was an early virtio console, assume that there are no
2138 * other consoles. We need to wait until the hvc_alloc matches the
2139 * hvc_instantiate, otherwise tty_open will complain, resulting in
2140 * a "Warning: unable to open an initial console" boot failure.
2141 * Without multiport this is done in add_port above. With multiport
2142 * this might take some host<->guest communication - thus we have to
2143 * wait.
2145 if (multiport && early)
2146 wait_for_completion(&early_console_added);
2148 return 0;
2150 free_chrdev:
2151 unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2152 free:
2153 kfree(portdev);
2154 fail:
2155 return err;
2158 static struct virtio_device_id id_table[] = {
2159 { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2160 { 0 },
2163 static unsigned int features[] = {
2164 VIRTIO_CONSOLE_F_SIZE,
2165 VIRTIO_CONSOLE_F_MULTIPORT,
2168 static struct virtio_device_id rproc_serial_id_table[] = {
2169 #if IS_ENABLED(CONFIG_REMOTEPROC)
2170 { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2171 #endif
2172 { 0 },
2175 static unsigned int rproc_serial_features[] = {
2178 #ifdef CONFIG_PM_SLEEP
2179 static int virtcons_freeze(struct virtio_device *vdev)
2181 struct ports_device *portdev;
2182 struct port *port;
2184 portdev = vdev->priv;
2186 vdev->config->reset(vdev);
2188 if (use_multiport(portdev))
2189 virtqueue_disable_cb(portdev->c_ivq);
2190 cancel_work_sync(&portdev->control_work);
2191 cancel_work_sync(&portdev->config_work);
2193 * Once more: if control_work_handler() was running, it would
2194 * enable the cb as the last step.
2196 if (use_multiport(portdev))
2197 virtqueue_disable_cb(portdev->c_ivq);
2199 list_for_each_entry(port, &portdev->ports, list) {
2200 virtqueue_disable_cb(port->in_vq);
2201 virtqueue_disable_cb(port->out_vq);
2203 * We'll ask the host later if the new invocation has
2204 * the port opened or closed.
2206 port->host_connected = false;
2207 remove_port_data(port);
2209 remove_vqs(portdev);
2211 return 0;
2214 static int virtcons_restore(struct virtio_device *vdev)
2216 struct ports_device *portdev;
2217 struct port *port;
2218 int ret;
2220 portdev = vdev->priv;
2222 ret = init_vqs(portdev);
2223 if (ret)
2224 return ret;
2226 virtio_device_ready(portdev->vdev);
2228 if (use_multiport(portdev))
2229 fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2231 list_for_each_entry(port, &portdev->ports, list) {
2232 port->in_vq = portdev->in_vqs[port->id];
2233 port->out_vq = portdev->out_vqs[port->id];
2235 fill_queue(port->in_vq, &port->inbuf_lock);
2237 /* Get port open/close status on the host */
2238 send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2241 * If a port was open at the time of suspending, we
2242 * have to let the host know that it's still open.
2244 if (port->guest_connected)
2245 send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2247 return 0;
2249 #endif
2251 static struct virtio_driver virtio_console = {
2252 .feature_table = features,
2253 .feature_table_size = ARRAY_SIZE(features),
2254 .driver.name = KBUILD_MODNAME,
2255 .driver.owner = THIS_MODULE,
2256 .id_table = id_table,
2257 .probe = virtcons_probe,
2258 .remove = virtcons_remove,
2259 .config_changed = config_intr,
2260 #ifdef CONFIG_PM_SLEEP
2261 .freeze = virtcons_freeze,
2262 .restore = virtcons_restore,
2263 #endif
2266 static struct virtio_driver virtio_rproc_serial = {
2267 .feature_table = rproc_serial_features,
2268 .feature_table_size = ARRAY_SIZE(rproc_serial_features),
2269 .driver.name = "virtio_rproc_serial",
2270 .driver.owner = THIS_MODULE,
2271 .id_table = rproc_serial_id_table,
2272 .probe = virtcons_probe,
2273 .remove = virtcons_remove,
2276 static int __init init(void)
2278 int err;
2280 pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2281 if (IS_ERR(pdrvdata.class)) {
2282 err = PTR_ERR(pdrvdata.class);
2283 pr_err("Error %d creating virtio-ports class\n", err);
2284 return err;
2287 pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2288 if (!pdrvdata.debugfs_dir)
2289 pr_warn("Error creating debugfs dir for virtio-ports\n");
2290 INIT_LIST_HEAD(&pdrvdata.consoles);
2291 INIT_LIST_HEAD(&pdrvdata.portdevs);
2293 err = register_virtio_driver(&virtio_console);
2294 if (err < 0) {
2295 pr_err("Error %d registering virtio driver\n", err);
2296 goto free;
2298 err = register_virtio_driver(&virtio_rproc_serial);
2299 if (err < 0) {
2300 pr_err("Error %d registering virtio rproc serial driver\n",
2301 err);
2302 goto unregister;
2304 return 0;
2305 unregister:
2306 unregister_virtio_driver(&virtio_console);
2307 free:
2308 debugfs_remove_recursive(pdrvdata.debugfs_dir);
2309 class_destroy(pdrvdata.class);
2310 return err;
2313 static void __exit fini(void)
2315 reclaim_dma_bufs();
2317 unregister_virtio_driver(&virtio_console);
2318 unregister_virtio_driver(&virtio_rproc_serial);
2320 class_destroy(pdrvdata.class);
2321 debugfs_remove_recursive(pdrvdata.debugfs_dir);
2323 module_init(init);
2324 module_exit(fini);
2326 MODULE_DEVICE_TABLE(virtio, id_table);
2327 MODULE_DESCRIPTION("Virtio console driver");
2328 MODULE_LICENSE("GPL");