xref: /openbmc/linux/drivers/char/virtio_console.c (revision 0b26ca68)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
4  * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
5  * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
6  */
7 #include <linux/cdev.h>
8 #include <linux/debugfs.h>
9 #include <linux/completion.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/freezer.h>
13 #include <linux/fs.h>
14 #include <linux/splice.h>
15 #include <linux/pagemap.h>
16 #include <linux/init.h>
17 #include <linux/list.h>
18 #include <linux/poll.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/spinlock.h>
22 #include <linux/virtio.h>
23 #include <linux/virtio_console.h>
24 #include <linux/wait.h>
25 #include <linux/workqueue.h>
26 #include <linux/module.h>
27 #include <linux/dma-mapping.h>
28 #include "../tty/hvc/hvc_console.h"
29 
30 #define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
31 
32 /*
33  * This is a global struct for storing common data for all the devices
34  * this driver handles.
35  *
36  * Mainly, it has a linked list for all the consoles in one place so
37  * that callbacks from hvc for get_chars(), put_chars() work properly
38  * across multiple devices and multiple ports per device.
39  */
40 struct ports_driver_data {
41 	/* Used for registering chardevs */
42 	struct class *class;
43 
44 	/* Used for exporting per-port information to debugfs */
45 	struct dentry *debugfs_dir;
46 
47 	/* List of all the devices we're handling */
48 	struct list_head portdevs;
49 
50 	/*
51 	 * This is used to keep track of the number of hvc consoles
52 	 * spawned by this driver.  This number is given as the first
53 	 * argument to hvc_alloc().  To correctly map an initial
54 	 * console spawned via hvc_instantiate to the console being
55 	 * hooked up via hvc_alloc, we need to pass the same vtermno.
56 	 *
57 	 * We also just assume the first console being initialised was
58 	 * the first one that got used as the initial console.
59 	 */
60 	unsigned int next_vtermno;
61 
62 	/* All the console devices handled by this driver */
63 	struct list_head consoles;
64 };
65 static struct ports_driver_data pdrvdata = { .next_vtermno = 1};
66 
67 static DEFINE_SPINLOCK(pdrvdata_lock);
68 static DECLARE_COMPLETION(early_console_added);
69 
70 /* This struct holds information that's relevant only for console ports */
71 struct console {
72 	/* We'll place all consoles in a list in the pdrvdata struct */
73 	struct list_head list;
74 
75 	/* The hvc device associated with this console port */
76 	struct hvc_struct *hvc;
77 
78 	/* The size of the console */
79 	struct winsize ws;
80 
81 	/*
82 	 * This number identifies the number that we used to register
83 	 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
84 	 * number passed on by the hvc callbacks to us to
85 	 * differentiate between the other console ports handled by
86 	 * this driver
87 	 */
88 	u32 vtermno;
89 };
90 
91 struct port_buffer {
92 	char *buf;
93 
94 	/* size of the buffer in *buf above */
95 	size_t size;
96 
97 	/* used length of the buffer */
98 	size_t len;
99 	/* offset in the buf from which to consume data */
100 	size_t offset;
101 
102 	/* DMA address of buffer */
103 	dma_addr_t dma;
104 
105 	/* Device we got DMA memory from */
106 	struct device *dev;
107 
108 	/* List of pending dma buffers to free */
109 	struct list_head list;
110 
111 	/* If sgpages == 0 then buf is used */
112 	unsigned int sgpages;
113 
114 	/* sg is used if spages > 0. sg must be the last in is struct */
115 	struct scatterlist sg[];
116 };
117 
118 /*
119  * This is a per-device struct that stores data common to all the
120  * ports for that device (vdev->priv).
121  */
122 struct ports_device {
123 	/* Next portdev in the list, head is in the pdrvdata struct */
124 	struct list_head list;
125 
126 	/*
127 	 * Workqueue handlers where we process deferred work after
128 	 * notification
129 	 */
130 	struct work_struct control_work;
131 	struct work_struct config_work;
132 
133 	struct list_head ports;
134 
135 	/* To protect the list of ports */
136 	spinlock_t ports_lock;
137 
138 	/* To protect the vq operations for the control channel */
139 	spinlock_t c_ivq_lock;
140 	spinlock_t c_ovq_lock;
141 
142 	/* max. number of ports this device can hold */
143 	u32 max_nr_ports;
144 
145 	/* The virtio device we're associated with */
146 	struct virtio_device *vdev;
147 
148 	/*
149 	 * A couple of virtqueues for the control channel: one for
150 	 * guest->host transfers, one for host->guest transfers
151 	 */
152 	struct virtqueue *c_ivq, *c_ovq;
153 
154 	/*
155 	 * A control packet buffer for guest->host requests, protected
156 	 * by c_ovq_lock.
157 	 */
158 	struct virtio_console_control cpkt;
159 
160 	/* Array of per-port IO virtqueues */
161 	struct virtqueue **in_vqs, **out_vqs;
162 
163 	/* Major number for this device.  Ports will be created as minors. */
164 	int chr_major;
165 };
166 
167 struct port_stats {
168 	unsigned long bytes_sent, bytes_received, bytes_discarded;
169 };
170 
171 /* This struct holds the per-port data */
172 struct port {
173 	/* Next port in the list, head is in the ports_device */
174 	struct list_head list;
175 
176 	/* Pointer to the parent virtio_console device */
177 	struct ports_device *portdev;
178 
179 	/* The current buffer from which data has to be fed to readers */
180 	struct port_buffer *inbuf;
181 
182 	/*
183 	 * To protect the operations on the in_vq associated with this
184 	 * port.  Has to be a spinlock because it can be called from
185 	 * interrupt context (get_char()).
186 	 */
187 	spinlock_t inbuf_lock;
188 
189 	/* Protect the operations on the out_vq. */
190 	spinlock_t outvq_lock;
191 
192 	/* The IO vqs for this port */
193 	struct virtqueue *in_vq, *out_vq;
194 
195 	/* File in the debugfs directory that exposes this port's information */
196 	struct dentry *debugfs_file;
197 
198 	/*
199 	 * Keep count of the bytes sent, received and discarded for
200 	 * this port for accounting and debugging purposes.  These
201 	 * counts are not reset across port open / close events.
202 	 */
203 	struct port_stats stats;
204 
205 	/*
206 	 * The entries in this struct will be valid if this port is
207 	 * hooked up to an hvc console
208 	 */
209 	struct console cons;
210 
211 	/* Each port associates with a separate char device */
212 	struct cdev *cdev;
213 	struct device *dev;
214 
215 	/* Reference-counting to handle port hot-unplugs and file operations */
216 	struct kref kref;
217 
218 	/* A waitqueue for poll() or blocking read operations */
219 	wait_queue_head_t waitqueue;
220 
221 	/* The 'name' of the port that we expose via sysfs properties */
222 	char *name;
223 
224 	/* We can notify apps of host connect / disconnect events via SIGIO */
225 	struct fasync_struct *async_queue;
226 
227 	/* The 'id' to identify the port with the Host */
228 	u32 id;
229 
230 	bool outvq_full;
231 
232 	/* Is the host device open */
233 	bool host_connected;
234 
235 	/* We should allow only one process to open a port */
236 	bool guest_connected;
237 };
238 
239 /* This is the very early arch-specified put chars function. */
240 static int (*early_put_chars)(u32, const char *, int);
241 
242 static struct port *find_port_by_vtermno(u32 vtermno)
243 {
244 	struct port *port;
245 	struct console *cons;
246 	unsigned long flags;
247 
248 	spin_lock_irqsave(&pdrvdata_lock, flags);
249 	list_for_each_entry(cons, &pdrvdata.consoles, list) {
250 		if (cons->vtermno == vtermno) {
251 			port = container_of(cons, struct port, cons);
252 			goto out;
253 		}
254 	}
255 	port = NULL;
256 out:
257 	spin_unlock_irqrestore(&pdrvdata_lock, flags);
258 	return port;
259 }
260 
261 static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
262 						 dev_t dev)
263 {
264 	struct port *port;
265 	unsigned long flags;
266 
267 	spin_lock_irqsave(&portdev->ports_lock, flags);
268 	list_for_each_entry(port, &portdev->ports, list) {
269 		if (port->cdev->dev == dev) {
270 			kref_get(&port->kref);
271 			goto out;
272 		}
273 	}
274 	port = NULL;
275 out:
276 	spin_unlock_irqrestore(&portdev->ports_lock, flags);
277 
278 	return port;
279 }
280 
281 static struct port *find_port_by_devt(dev_t dev)
282 {
283 	struct ports_device *portdev;
284 	struct port *port;
285 	unsigned long flags;
286 
287 	spin_lock_irqsave(&pdrvdata_lock, flags);
288 	list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
289 		port = find_port_by_devt_in_portdev(portdev, dev);
290 		if (port)
291 			goto out;
292 	}
293 	port = NULL;
294 out:
295 	spin_unlock_irqrestore(&pdrvdata_lock, flags);
296 	return port;
297 }
298 
299 static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
300 {
301 	struct port *port;
302 	unsigned long flags;
303 
304 	spin_lock_irqsave(&portdev->ports_lock, flags);
305 	list_for_each_entry(port, &portdev->ports, list)
306 		if (port->id == id)
307 			goto out;
308 	port = NULL;
309 out:
310 	spin_unlock_irqrestore(&portdev->ports_lock, flags);
311 
312 	return port;
313 }
314 
315 static struct port *find_port_by_vq(struct ports_device *portdev,
316 				    struct virtqueue *vq)
317 {
318 	struct port *port;
319 	unsigned long flags;
320 
321 	spin_lock_irqsave(&portdev->ports_lock, flags);
322 	list_for_each_entry(port, &portdev->ports, list)
323 		if (port->in_vq == vq || port->out_vq == vq)
324 			goto out;
325 	port = NULL;
326 out:
327 	spin_unlock_irqrestore(&portdev->ports_lock, flags);
328 	return port;
329 }
330 
331 static bool is_console_port(struct port *port)
332 {
333 	if (port->cons.hvc)
334 		return true;
335 	return false;
336 }
337 
338 static bool is_rproc_serial(const struct virtio_device *vdev)
339 {
340 	return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
341 }
342 
343 static inline bool use_multiport(struct ports_device *portdev)
344 {
345 	/*
346 	 * This condition can be true when put_chars is called from
347 	 * early_init
348 	 */
349 	if (!portdev->vdev)
350 		return false;
351 	return __virtio_test_bit(portdev->vdev, VIRTIO_CONSOLE_F_MULTIPORT);
352 }
353 
354 static DEFINE_SPINLOCK(dma_bufs_lock);
355 static LIST_HEAD(pending_free_dma_bufs);
356 
357 static void free_buf(struct port_buffer *buf, bool can_sleep)
358 {
359 	unsigned int i;
360 
361 	for (i = 0; i < buf->sgpages; i++) {
362 		struct page *page = sg_page(&buf->sg[i]);
363 		if (!page)
364 			break;
365 		put_page(page);
366 	}
367 
368 	if (!buf->dev) {
369 		kfree(buf->buf);
370 	} else if (is_rproc_enabled) {
371 		unsigned long flags;
372 
373 		/* dma_free_coherent requires interrupts to be enabled. */
374 		if (!can_sleep) {
375 			/* queue up dma-buffers to be freed later */
376 			spin_lock_irqsave(&dma_bufs_lock, flags);
377 			list_add_tail(&buf->list, &pending_free_dma_bufs);
378 			spin_unlock_irqrestore(&dma_bufs_lock, flags);
379 			return;
380 		}
381 		dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
382 
383 		/* Release device refcnt and allow it to be freed */
384 		put_device(buf->dev);
385 	}
386 
387 	kfree(buf);
388 }
389 
390 static void reclaim_dma_bufs(void)
391 {
392 	unsigned long flags;
393 	struct port_buffer *buf, *tmp;
394 	LIST_HEAD(tmp_list);
395 
396 	if (list_empty(&pending_free_dma_bufs))
397 		return;
398 
399 	/* Create a copy of the pending_free_dma_bufs while holding the lock */
400 	spin_lock_irqsave(&dma_bufs_lock, flags);
401 	list_cut_position(&tmp_list, &pending_free_dma_bufs,
402 			  pending_free_dma_bufs.prev);
403 	spin_unlock_irqrestore(&dma_bufs_lock, flags);
404 
405 	/* Release the dma buffers, without irqs enabled */
406 	list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
407 		list_del(&buf->list);
408 		free_buf(buf, true);
409 	}
410 }
411 
412 static struct port_buffer *alloc_buf(struct virtio_device *vdev, size_t buf_size,
413 				     int pages)
414 {
415 	struct port_buffer *buf;
416 
417 	reclaim_dma_bufs();
418 
419 	/*
420 	 * Allocate buffer and the sg list. The sg list array is allocated
421 	 * directly after the port_buffer struct.
422 	 */
423 	buf = kmalloc(struct_size(buf, sg, pages), GFP_KERNEL);
424 	if (!buf)
425 		goto fail;
426 
427 	buf->sgpages = pages;
428 	if (pages > 0) {
429 		buf->dev = NULL;
430 		buf->buf = NULL;
431 		return buf;
432 	}
433 
434 	if (is_rproc_serial(vdev)) {
435 		/*
436 		 * Allocate DMA memory from ancestor. When a virtio
437 		 * device is created by remoteproc, the DMA memory is
438 		 * associated with the parent device:
439 		 * virtioY => remoteprocX#vdevYbuffer.
440 		 */
441 		buf->dev = vdev->dev.parent;
442 		if (!buf->dev)
443 			goto free_buf;
444 
445 		/* Increase device refcnt to avoid freeing it */
446 		get_device(buf->dev);
447 		buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
448 					      GFP_KERNEL);
449 	} else {
450 		buf->dev = NULL;
451 		buf->buf = kmalloc(buf_size, GFP_KERNEL);
452 	}
453 
454 	if (!buf->buf)
455 		goto free_buf;
456 	buf->len = 0;
457 	buf->offset = 0;
458 	buf->size = buf_size;
459 	return buf;
460 
461 free_buf:
462 	kfree(buf);
463 fail:
464 	return NULL;
465 }
466 
467 /* Callers should take appropriate locks */
468 static struct port_buffer *get_inbuf(struct port *port)
469 {
470 	struct port_buffer *buf;
471 	unsigned int len;
472 
473 	if (port->inbuf)
474 		return port->inbuf;
475 
476 	buf = virtqueue_get_buf(port->in_vq, &len);
477 	if (buf) {
478 		buf->len = len;
479 		buf->offset = 0;
480 		port->stats.bytes_received += len;
481 	}
482 	return buf;
483 }
484 
485 /*
486  * Create a scatter-gather list representing our input buffer and put
487  * it in the queue.
488  *
489  * Callers should take appropriate locks.
490  */
491 static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
492 {
493 	struct scatterlist sg[1];
494 	int ret;
495 
496 	sg_init_one(sg, buf->buf, buf->size);
497 
498 	ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC);
499 	virtqueue_kick(vq);
500 	if (!ret)
501 		ret = vq->num_free;
502 	return ret;
503 }
504 
505 /* Discard any unread data this port has. Callers lockers. */
506 static void discard_port_data(struct port *port)
507 {
508 	struct port_buffer *buf;
509 	unsigned int err;
510 
511 	if (!port->portdev) {
512 		/* Device has been unplugged.  vqs are already gone. */
513 		return;
514 	}
515 	buf = get_inbuf(port);
516 
517 	err = 0;
518 	while (buf) {
519 		port->stats.bytes_discarded += buf->len - buf->offset;
520 		if (add_inbuf(port->in_vq, buf) < 0) {
521 			err++;
522 			free_buf(buf, false);
523 		}
524 		port->inbuf = NULL;
525 		buf = get_inbuf(port);
526 	}
527 	if (err)
528 		dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
529 			 err);
530 }
531 
532 static bool port_has_data(struct port *port)
533 {
534 	unsigned long flags;
535 	bool ret;
536 
537 	ret = false;
538 	spin_lock_irqsave(&port->inbuf_lock, flags);
539 	port->inbuf = get_inbuf(port);
540 	if (port->inbuf)
541 		ret = true;
542 
543 	spin_unlock_irqrestore(&port->inbuf_lock, flags);
544 	return ret;
545 }
546 
547 static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
548 				  unsigned int event, unsigned int value)
549 {
550 	struct scatterlist sg[1];
551 	struct virtqueue *vq;
552 	unsigned int len;
553 
554 	if (!use_multiport(portdev))
555 		return 0;
556 
557 	vq = portdev->c_ovq;
558 
559 	spin_lock(&portdev->c_ovq_lock);
560 
561 	portdev->cpkt.id = cpu_to_virtio32(portdev->vdev, port_id);
562 	portdev->cpkt.event = cpu_to_virtio16(portdev->vdev, event);
563 	portdev->cpkt.value = cpu_to_virtio16(portdev->vdev, value);
564 
565 	sg_init_one(sg, &portdev->cpkt, sizeof(struct virtio_console_control));
566 
567 	if (virtqueue_add_outbuf(vq, sg, 1, &portdev->cpkt, GFP_ATOMIC) == 0) {
568 		virtqueue_kick(vq);
569 		while (!virtqueue_get_buf(vq, &len)
570 			&& !virtqueue_is_broken(vq))
571 			cpu_relax();
572 	}
573 
574 	spin_unlock(&portdev->c_ovq_lock);
575 	return 0;
576 }
577 
578 static ssize_t send_control_msg(struct port *port, unsigned int event,
579 				unsigned int value)
580 {
581 	/* Did the port get unplugged before userspace closed it? */
582 	if (port->portdev)
583 		return __send_control_msg(port->portdev, port->id, event, value);
584 	return 0;
585 }
586 
587 
588 /* Callers must take the port->outvq_lock */
589 static void reclaim_consumed_buffers(struct port *port)
590 {
591 	struct port_buffer *buf;
592 	unsigned int len;
593 
594 	if (!port->portdev) {
595 		/* Device has been unplugged.  vqs are already gone. */
596 		return;
597 	}
598 	while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
599 		free_buf(buf, false);
600 		port->outvq_full = false;
601 	}
602 }
603 
604 static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
605 			      int nents, size_t in_count,
606 			      void *data, bool nonblock)
607 {
608 	struct virtqueue *out_vq;
609 	int err;
610 	unsigned long flags;
611 	unsigned int len;
612 
613 	out_vq = port->out_vq;
614 
615 	spin_lock_irqsave(&port->outvq_lock, flags);
616 
617 	reclaim_consumed_buffers(port);
618 
619 	err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
620 
621 	/* Tell Host to go! */
622 	virtqueue_kick(out_vq);
623 
624 	if (err) {
625 		in_count = 0;
626 		goto done;
627 	}
628 
629 	if (out_vq->num_free == 0)
630 		port->outvq_full = true;
631 
632 	if (nonblock)
633 		goto done;
634 
635 	/*
636 	 * Wait till the host acknowledges it pushed out the data we
637 	 * sent.  This is done for data from the hvc_console; the tty
638 	 * operations are performed with spinlocks held so we can't
639 	 * sleep here.  An alternative would be to copy the data to a
640 	 * buffer and relax the spinning requirement.  The downside is
641 	 * we need to kmalloc a GFP_ATOMIC buffer each time the
642 	 * console driver writes something out.
643 	 */
644 	while (!virtqueue_get_buf(out_vq, &len)
645 		&& !virtqueue_is_broken(out_vq))
646 		cpu_relax();
647 done:
648 	spin_unlock_irqrestore(&port->outvq_lock, flags);
649 
650 	port->stats.bytes_sent += in_count;
651 	/*
652 	 * We're expected to return the amount of data we wrote -- all
653 	 * of it
654 	 */
655 	return in_count;
656 }
657 
658 /*
659  * Give out the data that's requested from the buffer that we have
660  * queued up.
661  */
662 static ssize_t fill_readbuf(struct port *port, char __user *out_buf,
663 			    size_t out_count, bool to_user)
664 {
665 	struct port_buffer *buf;
666 	unsigned long flags;
667 
668 	if (!out_count || !port_has_data(port))
669 		return 0;
670 
671 	buf = port->inbuf;
672 	out_count = min(out_count, buf->len - buf->offset);
673 
674 	if (to_user) {
675 		ssize_t ret;
676 
677 		ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
678 		if (ret)
679 			return -EFAULT;
680 	} else {
681 		memcpy((__force char *)out_buf, buf->buf + buf->offset,
682 		       out_count);
683 	}
684 
685 	buf->offset += out_count;
686 
687 	if (buf->offset == buf->len) {
688 		/*
689 		 * We're done using all the data in this buffer.
690 		 * Re-queue so that the Host can send us more data.
691 		 */
692 		spin_lock_irqsave(&port->inbuf_lock, flags);
693 		port->inbuf = NULL;
694 
695 		if (add_inbuf(port->in_vq, buf) < 0)
696 			dev_warn(port->dev, "failed add_buf\n");
697 
698 		spin_unlock_irqrestore(&port->inbuf_lock, flags);
699 	}
700 	/* Return the number of bytes actually copied */
701 	return out_count;
702 }
703 
704 /* The condition that must be true for polling to end */
705 static bool will_read_block(struct port *port)
706 {
707 	if (!port->guest_connected) {
708 		/* Port got hot-unplugged. Let's exit. */
709 		return false;
710 	}
711 	return !port_has_data(port) && port->host_connected;
712 }
713 
714 static bool will_write_block(struct port *port)
715 {
716 	bool ret;
717 
718 	if (!port->guest_connected) {
719 		/* Port got hot-unplugged. Let's exit. */
720 		return false;
721 	}
722 	if (!port->host_connected)
723 		return true;
724 
725 	spin_lock_irq(&port->outvq_lock);
726 	/*
727 	 * Check if the Host has consumed any buffers since we last
728 	 * sent data (this is only applicable for nonblocking ports).
729 	 */
730 	reclaim_consumed_buffers(port);
731 	ret = port->outvq_full;
732 	spin_unlock_irq(&port->outvq_lock);
733 
734 	return ret;
735 }
736 
737 static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
738 			      size_t count, loff_t *offp)
739 {
740 	struct port *port;
741 	ssize_t ret;
742 
743 	port = filp->private_data;
744 
745 	/* Port is hot-unplugged. */
746 	if (!port->guest_connected)
747 		return -ENODEV;
748 
749 	if (!port_has_data(port)) {
750 		/*
751 		 * If nothing's connected on the host just return 0 in
752 		 * case of list_empty; this tells the userspace app
753 		 * that there's no connection
754 		 */
755 		if (!port->host_connected)
756 			return 0;
757 		if (filp->f_flags & O_NONBLOCK)
758 			return -EAGAIN;
759 
760 		ret = wait_event_freezable(port->waitqueue,
761 					   !will_read_block(port));
762 		if (ret < 0)
763 			return ret;
764 	}
765 	/* Port got hot-unplugged while we were waiting above. */
766 	if (!port->guest_connected)
767 		return -ENODEV;
768 	/*
769 	 * We could've received a disconnection message while we were
770 	 * waiting for more data.
771 	 *
772 	 * This check is not clubbed in the if() statement above as we
773 	 * might receive some data as well as the host could get
774 	 * disconnected after we got woken up from our wait.  So we
775 	 * really want to give off whatever data we have and only then
776 	 * check for host_connected.
777 	 */
778 	if (!port_has_data(port) && !port->host_connected)
779 		return 0;
780 
781 	return fill_readbuf(port, ubuf, count, true);
782 }
783 
784 static int wait_port_writable(struct port *port, bool nonblock)
785 {
786 	int ret;
787 
788 	if (will_write_block(port)) {
789 		if (nonblock)
790 			return -EAGAIN;
791 
792 		ret = wait_event_freezable(port->waitqueue,
793 					   !will_write_block(port));
794 		if (ret < 0)
795 			return ret;
796 	}
797 	/* Port got hot-unplugged. */
798 	if (!port->guest_connected)
799 		return -ENODEV;
800 
801 	return 0;
802 }
803 
804 static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
805 			       size_t count, loff_t *offp)
806 {
807 	struct port *port;
808 	struct port_buffer *buf;
809 	ssize_t ret;
810 	bool nonblock;
811 	struct scatterlist sg[1];
812 
813 	/* Userspace could be out to fool us */
814 	if (!count)
815 		return 0;
816 
817 	port = filp->private_data;
818 
819 	nonblock = filp->f_flags & O_NONBLOCK;
820 
821 	ret = wait_port_writable(port, nonblock);
822 	if (ret < 0)
823 		return ret;
824 
825 	count = min((size_t)(32 * 1024), count);
826 
827 	buf = alloc_buf(port->portdev->vdev, count, 0);
828 	if (!buf)
829 		return -ENOMEM;
830 
831 	ret = copy_from_user(buf->buf, ubuf, count);
832 	if (ret) {
833 		ret = -EFAULT;
834 		goto free_buf;
835 	}
836 
837 	/*
838 	 * We now ask send_buf() to not spin for generic ports -- we
839 	 * can re-use the same code path that non-blocking file
840 	 * descriptors take for blocking file descriptors since the
841 	 * wait is already done and we're certain the write will go
842 	 * through to the host.
843 	 */
844 	nonblock = true;
845 	sg_init_one(sg, buf->buf, count);
846 	ret = __send_to_port(port, sg, 1, count, buf, nonblock);
847 
848 	if (nonblock && ret > 0)
849 		goto out;
850 
851 free_buf:
852 	free_buf(buf, true);
853 out:
854 	return ret;
855 }
856 
857 struct sg_list {
858 	unsigned int n;
859 	unsigned int size;
860 	size_t len;
861 	struct scatterlist *sg;
862 };
863 
864 static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
865 			struct splice_desc *sd)
866 {
867 	struct sg_list *sgl = sd->u.data;
868 	unsigned int offset, len;
869 
870 	if (sgl->n == sgl->size)
871 		return 0;
872 
873 	/* Try lock this page */
874 	if (pipe_buf_try_steal(pipe, buf)) {
875 		/* Get reference and unlock page for moving */
876 		get_page(buf->page);
877 		unlock_page(buf->page);
878 
879 		len = min(buf->len, sd->len);
880 		sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
881 	} else {
882 		/* Failback to copying a page */
883 		struct page *page = alloc_page(GFP_KERNEL);
884 		char *src;
885 
886 		if (!page)
887 			return -ENOMEM;
888 
889 		offset = sd->pos & ~PAGE_MASK;
890 
891 		len = sd->len;
892 		if (len + offset > PAGE_SIZE)
893 			len = PAGE_SIZE - offset;
894 
895 		src = kmap_atomic(buf->page);
896 		memcpy(page_address(page) + offset, src + buf->offset, len);
897 		kunmap_atomic(src);
898 
899 		sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
900 	}
901 	sgl->n++;
902 	sgl->len += len;
903 
904 	return len;
905 }
906 
907 /* Faster zero-copy write by splicing */
908 static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
909 				      struct file *filp, loff_t *ppos,
910 				      size_t len, unsigned int flags)
911 {
912 	struct port *port = filp->private_data;
913 	struct sg_list sgl;
914 	ssize_t ret;
915 	struct port_buffer *buf;
916 	struct splice_desc sd = {
917 		.total_len = len,
918 		.flags = flags,
919 		.pos = *ppos,
920 		.u.data = &sgl,
921 	};
922 	unsigned int occupancy;
923 
924 	/*
925 	 * Rproc_serial does not yet support splice. To support splice
926 	 * pipe_to_sg() must allocate dma-buffers and copy content from
927 	 * regular pages to dma pages. And alloc_buf and free_buf must
928 	 * support allocating and freeing such a list of dma-buffers.
929 	 */
930 	if (is_rproc_serial(port->out_vq->vdev))
931 		return -EINVAL;
932 
933 	pipe_lock(pipe);
934 	ret = 0;
935 	if (pipe_empty(pipe->head, pipe->tail))
936 		goto error_out;
937 
938 	ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
939 	if (ret < 0)
940 		goto error_out;
941 
942 	occupancy = pipe_occupancy(pipe->head, pipe->tail);
943 	buf = alloc_buf(port->portdev->vdev, 0, occupancy);
944 
945 	if (!buf) {
946 		ret = -ENOMEM;
947 		goto error_out;
948 	}
949 
950 	sgl.n = 0;
951 	sgl.len = 0;
952 	sgl.size = occupancy;
953 	sgl.sg = buf->sg;
954 	sg_init_table(sgl.sg, sgl.size);
955 	ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
956 	pipe_unlock(pipe);
957 	if (likely(ret > 0))
958 		ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
959 
960 	if (unlikely(ret <= 0))
961 		free_buf(buf, true);
962 	return ret;
963 
964 error_out:
965 	pipe_unlock(pipe);
966 	return ret;
967 }
968 
969 static __poll_t port_fops_poll(struct file *filp, poll_table *wait)
970 {
971 	struct port *port;
972 	__poll_t ret;
973 
974 	port = filp->private_data;
975 	poll_wait(filp, &port->waitqueue, wait);
976 
977 	if (!port->guest_connected) {
978 		/* Port got unplugged */
979 		return EPOLLHUP;
980 	}
981 	ret = 0;
982 	if (!will_read_block(port))
983 		ret |= EPOLLIN | EPOLLRDNORM;
984 	if (!will_write_block(port))
985 		ret |= EPOLLOUT;
986 	if (!port->host_connected)
987 		ret |= EPOLLHUP;
988 
989 	return ret;
990 }
991 
992 static void remove_port(struct kref *kref);
993 
994 static int port_fops_release(struct inode *inode, struct file *filp)
995 {
996 	struct port *port;
997 
998 	port = filp->private_data;
999 
1000 	/* Notify host of port being closed */
1001 	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1002 
1003 	spin_lock_irq(&port->inbuf_lock);
1004 	port->guest_connected = false;
1005 
1006 	discard_port_data(port);
1007 
1008 	spin_unlock_irq(&port->inbuf_lock);
1009 
1010 	spin_lock_irq(&port->outvq_lock);
1011 	reclaim_consumed_buffers(port);
1012 	spin_unlock_irq(&port->outvq_lock);
1013 
1014 	reclaim_dma_bufs();
1015 	/*
1016 	 * Locks aren't necessary here as a port can't be opened after
1017 	 * unplug, and if a port isn't unplugged, a kref would already
1018 	 * exist for the port.  Plus, taking ports_lock here would
1019 	 * create a dependency on other locks taken by functions
1020 	 * inside remove_port if we're the last holder of the port,
1021 	 * creating many problems.
1022 	 */
1023 	kref_put(&port->kref, remove_port);
1024 
1025 	return 0;
1026 }
1027 
1028 static int port_fops_open(struct inode *inode, struct file *filp)
1029 {
1030 	struct cdev *cdev = inode->i_cdev;
1031 	struct port *port;
1032 	int ret;
1033 
1034 	/* We get the port with a kref here */
1035 	port = find_port_by_devt(cdev->dev);
1036 	if (!port) {
1037 		/* Port was unplugged before we could proceed */
1038 		return -ENXIO;
1039 	}
1040 	filp->private_data = port;
1041 
1042 	/*
1043 	 * Don't allow opening of console port devices -- that's done
1044 	 * via /dev/hvc
1045 	 */
1046 	if (is_console_port(port)) {
1047 		ret = -ENXIO;
1048 		goto out;
1049 	}
1050 
1051 	/* Allow only one process to open a particular port at a time */
1052 	spin_lock_irq(&port->inbuf_lock);
1053 	if (port->guest_connected) {
1054 		spin_unlock_irq(&port->inbuf_lock);
1055 		ret = -EBUSY;
1056 		goto out;
1057 	}
1058 
1059 	port->guest_connected = true;
1060 	spin_unlock_irq(&port->inbuf_lock);
1061 
1062 	spin_lock_irq(&port->outvq_lock);
1063 	/*
1064 	 * There might be a chance that we missed reclaiming a few
1065 	 * buffers in the window of the port getting previously closed
1066 	 * and opening now.
1067 	 */
1068 	reclaim_consumed_buffers(port);
1069 	spin_unlock_irq(&port->outvq_lock);
1070 
1071 	nonseekable_open(inode, filp);
1072 
1073 	/* Notify host of port being opened */
1074 	send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1075 
1076 	return 0;
1077 out:
1078 	kref_put(&port->kref, remove_port);
1079 	return ret;
1080 }
1081 
1082 static int port_fops_fasync(int fd, struct file *filp, int mode)
1083 {
1084 	struct port *port;
1085 
1086 	port = filp->private_data;
1087 	return fasync_helper(fd, filp, mode, &port->async_queue);
1088 }
1089 
1090 /*
1091  * The file operations that we support: programs in the guest can open
1092  * a console device, read from it, write to it, poll for data and
1093  * close it.  The devices are at
1094  *   /dev/vport<device number>p<port number>
1095  */
1096 static const struct file_operations port_fops = {
1097 	.owner = THIS_MODULE,
1098 	.open  = port_fops_open,
1099 	.read  = port_fops_read,
1100 	.write = port_fops_write,
1101 	.splice_write = port_fops_splice_write,
1102 	.poll  = port_fops_poll,
1103 	.release = port_fops_release,
1104 	.fasync = port_fops_fasync,
1105 	.llseek = no_llseek,
1106 };
1107 
1108 /*
1109  * The put_chars() callback is pretty straightforward.
1110  *
1111  * We turn the characters into a scatter-gather list, add it to the
1112  * output queue and then kick the Host.  Then we sit here waiting for
1113  * it to finish: inefficient in theory, but in practice
1114  * implementations will do it immediately.
1115  */
1116 static int put_chars(u32 vtermno, const char *buf, int count)
1117 {
1118 	struct port *port;
1119 	struct scatterlist sg[1];
1120 	void *data;
1121 	int ret;
1122 
1123 	if (unlikely(early_put_chars))
1124 		return early_put_chars(vtermno, buf, count);
1125 
1126 	port = find_port_by_vtermno(vtermno);
1127 	if (!port)
1128 		return -EPIPE;
1129 
1130 	data = kmemdup(buf, count, GFP_ATOMIC);
1131 	if (!data)
1132 		return -ENOMEM;
1133 
1134 	sg_init_one(sg, data, count);
1135 	ret = __send_to_port(port, sg, 1, count, data, false);
1136 	kfree(data);
1137 	return ret;
1138 }
1139 
1140 /*
1141  * get_chars() is the callback from the hvc_console infrastructure
1142  * when an interrupt is received.
1143  *
1144  * We call out to fill_readbuf that gets us the required data from the
1145  * buffers that are queued up.
1146  */
1147 static int get_chars(u32 vtermno, char *buf, int count)
1148 {
1149 	struct port *port;
1150 
1151 	/* If we've not set up the port yet, we have no input to give. */
1152 	if (unlikely(early_put_chars))
1153 		return 0;
1154 
1155 	port = find_port_by_vtermno(vtermno);
1156 	if (!port)
1157 		return -EPIPE;
1158 
1159 	/* If we don't have an input queue yet, we can't get input. */
1160 	BUG_ON(!port->in_vq);
1161 
1162 	return fill_readbuf(port, (__force char __user *)buf, count, false);
1163 }
1164 
1165 static void resize_console(struct port *port)
1166 {
1167 	struct virtio_device *vdev;
1168 
1169 	/* The port could have been hot-unplugged */
1170 	if (!port || !is_console_port(port))
1171 		return;
1172 
1173 	vdev = port->portdev->vdev;
1174 
1175 	/* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1176 	if (!is_rproc_serial(vdev) &&
1177 	    virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1178 		hvc_resize(port->cons.hvc, port->cons.ws);
1179 }
1180 
1181 /* We set the configuration at this point, since we now have a tty */
1182 static int notifier_add_vio(struct hvc_struct *hp, int data)
1183 {
1184 	struct port *port;
1185 
1186 	port = find_port_by_vtermno(hp->vtermno);
1187 	if (!port)
1188 		return -EINVAL;
1189 
1190 	hp->irq_requested = 1;
1191 	resize_console(port);
1192 
1193 	return 0;
1194 }
1195 
1196 static void notifier_del_vio(struct hvc_struct *hp, int data)
1197 {
1198 	hp->irq_requested = 0;
1199 }
1200 
1201 /* The operations for console ports. */
1202 static const struct hv_ops hv_ops = {
1203 	.get_chars = get_chars,
1204 	.put_chars = put_chars,
1205 	.notifier_add = notifier_add_vio,
1206 	.notifier_del = notifier_del_vio,
1207 	.notifier_hangup = notifier_del_vio,
1208 };
1209 
1210 /*
1211  * Console drivers are initialized very early so boot messages can go
1212  * out, so we do things slightly differently from the generic virtio
1213  * initialization of the net and block drivers.
1214  *
1215  * At this stage, the console is output-only.  It's too early to set
1216  * up a virtqueue, so we let the drivers do some boutique early-output
1217  * thing.
1218  */
1219 int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
1220 {
1221 	early_put_chars = put_chars;
1222 	return hvc_instantiate(0, 0, &hv_ops);
1223 }
1224 
1225 static int init_port_console(struct port *port)
1226 {
1227 	int ret;
1228 
1229 	/*
1230 	 * The Host's telling us this port is a console port.  Hook it
1231 	 * up with an hvc console.
1232 	 *
1233 	 * To set up and manage our virtual console, we call
1234 	 * hvc_alloc().
1235 	 *
1236 	 * The first argument of hvc_alloc() is the virtual console
1237 	 * number.  The second argument is the parameter for the
1238 	 * notification mechanism (like irq number).  We currently
1239 	 * leave this as zero, virtqueues have implicit notifications.
1240 	 *
1241 	 * The third argument is a "struct hv_ops" containing the
1242 	 * put_chars() get_chars(), notifier_add() and notifier_del()
1243 	 * pointers.  The final argument is the output buffer size: we
1244 	 * can do any size, so we put PAGE_SIZE here.
1245 	 */
1246 	port->cons.vtermno = pdrvdata.next_vtermno;
1247 
1248 	port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1249 	if (IS_ERR(port->cons.hvc)) {
1250 		ret = PTR_ERR(port->cons.hvc);
1251 		dev_err(port->dev,
1252 			"error %d allocating hvc for port\n", ret);
1253 		port->cons.hvc = NULL;
1254 		return ret;
1255 	}
1256 	spin_lock_irq(&pdrvdata_lock);
1257 	pdrvdata.next_vtermno++;
1258 	list_add_tail(&port->cons.list, &pdrvdata.consoles);
1259 	spin_unlock_irq(&pdrvdata_lock);
1260 	port->guest_connected = true;
1261 
1262 	/*
1263 	 * Start using the new console output if this is the first
1264 	 * console to come up.
1265 	 */
1266 	if (early_put_chars)
1267 		early_put_chars = NULL;
1268 
1269 	/* Notify host of port being opened */
1270 	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1271 
1272 	return 0;
1273 }
1274 
1275 static ssize_t show_port_name(struct device *dev,
1276 			      struct device_attribute *attr, char *buffer)
1277 {
1278 	struct port *port;
1279 
1280 	port = dev_get_drvdata(dev);
1281 
1282 	return sprintf(buffer, "%s\n", port->name);
1283 }
1284 
1285 static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1286 
1287 static struct attribute *port_sysfs_entries[] = {
1288 	&dev_attr_name.attr,
1289 	NULL
1290 };
1291 
1292 static const struct attribute_group port_attribute_group = {
1293 	.name = NULL,		/* put in device directory */
1294 	.attrs = port_sysfs_entries,
1295 };
1296 
1297 static int port_debugfs_show(struct seq_file *s, void *data)
1298 {
1299 	struct port *port = s->private;
1300 
1301 	seq_printf(s, "name: %s\n", port->name ? port->name : "");
1302 	seq_printf(s, "guest_connected: %d\n", port->guest_connected);
1303 	seq_printf(s, "host_connected: %d\n", port->host_connected);
1304 	seq_printf(s, "outvq_full: %d\n", port->outvq_full);
1305 	seq_printf(s, "bytes_sent: %lu\n", port->stats.bytes_sent);
1306 	seq_printf(s, "bytes_received: %lu\n", port->stats.bytes_received);
1307 	seq_printf(s, "bytes_discarded: %lu\n", port->stats.bytes_discarded);
1308 	seq_printf(s, "is_console: %s\n",
1309 		   is_console_port(port) ? "yes" : "no");
1310 	seq_printf(s, "console_vtermno: %u\n", port->cons.vtermno);
1311 
1312 	return 0;
1313 }
1314 
1315 DEFINE_SHOW_ATTRIBUTE(port_debugfs);
1316 
1317 static void set_console_size(struct port *port, u16 rows, u16 cols)
1318 {
1319 	if (!port || !is_console_port(port))
1320 		return;
1321 
1322 	port->cons.ws.ws_row = rows;
1323 	port->cons.ws.ws_col = cols;
1324 }
1325 
1326 static int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1327 {
1328 	struct port_buffer *buf;
1329 	int nr_added_bufs;
1330 	int ret;
1331 
1332 	nr_added_bufs = 0;
1333 	do {
1334 		buf = alloc_buf(vq->vdev, PAGE_SIZE, 0);
1335 		if (!buf)
1336 			return -ENOMEM;
1337 
1338 		spin_lock_irq(lock);
1339 		ret = add_inbuf(vq, buf);
1340 		if (ret < 0) {
1341 			spin_unlock_irq(lock);
1342 			free_buf(buf, true);
1343 			return ret;
1344 		}
1345 		nr_added_bufs++;
1346 		spin_unlock_irq(lock);
1347 	} while (ret > 0);
1348 
1349 	return nr_added_bufs;
1350 }
1351 
1352 static void send_sigio_to_port(struct port *port)
1353 {
1354 	if (port->async_queue && port->guest_connected)
1355 		kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1356 }
1357 
1358 static int add_port(struct ports_device *portdev, u32 id)
1359 {
1360 	char debugfs_name[16];
1361 	struct port *port;
1362 	dev_t devt;
1363 	int err;
1364 
1365 	port = kmalloc(sizeof(*port), GFP_KERNEL);
1366 	if (!port) {
1367 		err = -ENOMEM;
1368 		goto fail;
1369 	}
1370 	kref_init(&port->kref);
1371 
1372 	port->portdev = portdev;
1373 	port->id = id;
1374 
1375 	port->name = NULL;
1376 	port->inbuf = NULL;
1377 	port->cons.hvc = NULL;
1378 	port->async_queue = NULL;
1379 
1380 	port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1381 	port->cons.vtermno = 0;
1382 
1383 	port->host_connected = port->guest_connected = false;
1384 	port->stats = (struct port_stats) { 0 };
1385 
1386 	port->outvq_full = false;
1387 
1388 	port->in_vq = portdev->in_vqs[port->id];
1389 	port->out_vq = portdev->out_vqs[port->id];
1390 
1391 	port->cdev = cdev_alloc();
1392 	if (!port->cdev) {
1393 		dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1394 		err = -ENOMEM;
1395 		goto free_port;
1396 	}
1397 	port->cdev->ops = &port_fops;
1398 
1399 	devt = MKDEV(portdev->chr_major, id);
1400 	err = cdev_add(port->cdev, devt, 1);
1401 	if (err < 0) {
1402 		dev_err(&port->portdev->vdev->dev,
1403 			"Error %d adding cdev for port %u\n", err, id);
1404 		goto free_cdev;
1405 	}
1406 	port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1407 				  devt, port, "vport%up%u",
1408 				  port->portdev->vdev->index, id);
1409 	if (IS_ERR(port->dev)) {
1410 		err = PTR_ERR(port->dev);
1411 		dev_err(&port->portdev->vdev->dev,
1412 			"Error %d creating device for port %u\n",
1413 			err, id);
1414 		goto free_cdev;
1415 	}
1416 
1417 	spin_lock_init(&port->inbuf_lock);
1418 	spin_lock_init(&port->outvq_lock);
1419 	init_waitqueue_head(&port->waitqueue);
1420 
1421 	/* We can safely ignore ENOSPC because it means
1422 	 * the queue already has buffers. Buffers are removed
1423 	 * only by virtcons_remove(), not by unplug_port()
1424 	 */
1425 	err = fill_queue(port->in_vq, &port->inbuf_lock);
1426 	if (err < 0 && err != -ENOSPC) {
1427 		dev_err(port->dev, "Error allocating inbufs\n");
1428 		goto free_device;
1429 	}
1430 
1431 	if (is_rproc_serial(port->portdev->vdev))
1432 		/*
1433 		 * For rproc_serial assume remote processor is connected.
1434 		 * rproc_serial does not want the console port, only
1435 		 * the generic port implementation.
1436 		 */
1437 		port->host_connected = true;
1438 	else if (!use_multiport(port->portdev)) {
1439 		/*
1440 		 * If we're not using multiport support,
1441 		 * this has to be a console port.
1442 		 */
1443 		err = init_port_console(port);
1444 		if (err)
1445 			goto free_inbufs;
1446 	}
1447 
1448 	spin_lock_irq(&portdev->ports_lock);
1449 	list_add_tail(&port->list, &port->portdev->ports);
1450 	spin_unlock_irq(&portdev->ports_lock);
1451 
1452 	/*
1453 	 * Tell the Host we're set so that it can send us various
1454 	 * configuration parameters for this port (eg, port name,
1455 	 * caching, whether this is a console port, etc.)
1456 	 */
1457 	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1458 
1459 	if (pdrvdata.debugfs_dir) {
1460 		/*
1461 		 * Finally, create the debugfs file that we can use to
1462 		 * inspect a port's state at any time
1463 		 */
1464 		snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
1465 			 port->portdev->vdev->index, id);
1466 		port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1467 							 pdrvdata.debugfs_dir,
1468 							 port,
1469 							 &port_debugfs_fops);
1470 	}
1471 	return 0;
1472 
1473 free_inbufs:
1474 free_device:
1475 	device_destroy(pdrvdata.class, port->dev->devt);
1476 free_cdev:
1477 	cdev_del(port->cdev);
1478 free_port:
1479 	kfree(port);
1480 fail:
1481 	/* The host might want to notify management sw about port add failure */
1482 	__send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1483 	return err;
1484 }
1485 
1486 /* No users remain, remove all port-specific data. */
1487 static void remove_port(struct kref *kref)
1488 {
1489 	struct port *port;
1490 
1491 	port = container_of(kref, struct port, kref);
1492 
1493 	kfree(port);
1494 }
1495 
1496 static void remove_port_data(struct port *port)
1497 {
1498 	spin_lock_irq(&port->inbuf_lock);
1499 	/* Remove unused data this port might have received. */
1500 	discard_port_data(port);
1501 	spin_unlock_irq(&port->inbuf_lock);
1502 
1503 	spin_lock_irq(&port->outvq_lock);
1504 	reclaim_consumed_buffers(port);
1505 	spin_unlock_irq(&port->outvq_lock);
1506 }
1507 
1508 /*
1509  * Port got unplugged.  Remove port from portdev's list and drop the
1510  * kref reference.  If no userspace has this port opened, it will
1511  * result in immediate removal the port.
1512  */
1513 static void unplug_port(struct port *port)
1514 {
1515 	spin_lock_irq(&port->portdev->ports_lock);
1516 	list_del(&port->list);
1517 	spin_unlock_irq(&port->portdev->ports_lock);
1518 
1519 	spin_lock_irq(&port->inbuf_lock);
1520 	if (port->guest_connected) {
1521 		/* Let the app know the port is going down. */
1522 		send_sigio_to_port(port);
1523 
1524 		/* Do this after sigio is actually sent */
1525 		port->guest_connected = false;
1526 		port->host_connected = false;
1527 
1528 		wake_up_interruptible(&port->waitqueue);
1529 	}
1530 	spin_unlock_irq(&port->inbuf_lock);
1531 
1532 	if (is_console_port(port)) {
1533 		spin_lock_irq(&pdrvdata_lock);
1534 		list_del(&port->cons.list);
1535 		spin_unlock_irq(&pdrvdata_lock);
1536 		hvc_remove(port->cons.hvc);
1537 	}
1538 
1539 	remove_port_data(port);
1540 
1541 	/*
1542 	 * We should just assume the device itself has gone off --
1543 	 * else a close on an open port later will try to send out a
1544 	 * control message.
1545 	 */
1546 	port->portdev = NULL;
1547 
1548 	sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1549 	device_destroy(pdrvdata.class, port->dev->devt);
1550 	cdev_del(port->cdev);
1551 
1552 	debugfs_remove(port->debugfs_file);
1553 	kfree(port->name);
1554 
1555 	/*
1556 	 * Locks around here are not necessary - a port can't be
1557 	 * opened after we removed the port struct from ports_list
1558 	 * above.
1559 	 */
1560 	kref_put(&port->kref, remove_port);
1561 }
1562 
1563 /* Any private messages that the Host and Guest want to share */
1564 static void handle_control_message(struct virtio_device *vdev,
1565 				   struct ports_device *portdev,
1566 				   struct port_buffer *buf)
1567 {
1568 	struct virtio_console_control *cpkt;
1569 	struct port *port;
1570 	size_t name_size;
1571 	int err;
1572 
1573 	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1574 
1575 	port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
1576 	if (!port &&
1577 	    cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
1578 		/* No valid header at start of buffer.  Drop it. */
1579 		dev_dbg(&portdev->vdev->dev,
1580 			"Invalid index %u in control packet\n", cpkt->id);
1581 		return;
1582 	}
1583 
1584 	switch (virtio16_to_cpu(vdev, cpkt->event)) {
1585 	case VIRTIO_CONSOLE_PORT_ADD:
1586 		if (port) {
1587 			dev_dbg(&portdev->vdev->dev,
1588 				"Port %u already added\n", port->id);
1589 			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1590 			break;
1591 		}
1592 		if (virtio32_to_cpu(vdev, cpkt->id) >=
1593 		    portdev->max_nr_ports) {
1594 			dev_warn(&portdev->vdev->dev,
1595 				"Request for adding port with "
1596 				"out-of-bound id %u, max. supported id: %u\n",
1597 				cpkt->id, portdev->max_nr_ports - 1);
1598 			break;
1599 		}
1600 		add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
1601 		break;
1602 	case VIRTIO_CONSOLE_PORT_REMOVE:
1603 		unplug_port(port);
1604 		break;
1605 	case VIRTIO_CONSOLE_CONSOLE_PORT:
1606 		if (!cpkt->value)
1607 			break;
1608 		if (is_console_port(port))
1609 			break;
1610 
1611 		init_port_console(port);
1612 		complete(&early_console_added);
1613 		/*
1614 		 * Could remove the port here in case init fails - but
1615 		 * have to notify the host first.
1616 		 */
1617 		break;
1618 	case VIRTIO_CONSOLE_RESIZE: {
1619 		struct {
1620 			__u16 rows;
1621 			__u16 cols;
1622 		} size;
1623 
1624 		if (!is_console_port(port))
1625 			break;
1626 
1627 		memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1628 		       sizeof(size));
1629 		set_console_size(port, size.rows, size.cols);
1630 
1631 		port->cons.hvc->irq_requested = 1;
1632 		resize_console(port);
1633 		break;
1634 	}
1635 	case VIRTIO_CONSOLE_PORT_OPEN:
1636 		port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
1637 		wake_up_interruptible(&port->waitqueue);
1638 		/*
1639 		 * If the host port got closed and the host had any
1640 		 * unconsumed buffers, we'll be able to reclaim them
1641 		 * now.
1642 		 */
1643 		spin_lock_irq(&port->outvq_lock);
1644 		reclaim_consumed_buffers(port);
1645 		spin_unlock_irq(&port->outvq_lock);
1646 
1647 		/*
1648 		 * If the guest is connected, it'll be interested in
1649 		 * knowing the host connection state changed.
1650 		 */
1651 		spin_lock_irq(&port->inbuf_lock);
1652 		send_sigio_to_port(port);
1653 		spin_unlock_irq(&port->inbuf_lock);
1654 		break;
1655 	case VIRTIO_CONSOLE_PORT_NAME:
1656 		/*
1657 		 * If we woke up after hibernation, we can get this
1658 		 * again.  Skip it in that case.
1659 		 */
1660 		if (port->name)
1661 			break;
1662 
1663 		/*
1664 		 * Skip the size of the header and the cpkt to get the size
1665 		 * of the name that was sent
1666 		 */
1667 		name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1668 
1669 		port->name = kmalloc(name_size, GFP_KERNEL);
1670 		if (!port->name) {
1671 			dev_err(port->dev,
1672 				"Not enough space to store port name\n");
1673 			break;
1674 		}
1675 		strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1676 			name_size - 1);
1677 		port->name[name_size - 1] = 0;
1678 
1679 		/*
1680 		 * Since we only have one sysfs attribute, 'name',
1681 		 * create it only if we have a name for the port.
1682 		 */
1683 		err = sysfs_create_group(&port->dev->kobj,
1684 					 &port_attribute_group);
1685 		if (err) {
1686 			dev_err(port->dev,
1687 				"Error %d creating sysfs device attributes\n",
1688 				err);
1689 		} else {
1690 			/*
1691 			 * Generate a udev event so that appropriate
1692 			 * symlinks can be created based on udev
1693 			 * rules.
1694 			 */
1695 			kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1696 		}
1697 		break;
1698 	}
1699 }
1700 
1701 static void control_work_handler(struct work_struct *work)
1702 {
1703 	struct ports_device *portdev;
1704 	struct virtqueue *vq;
1705 	struct port_buffer *buf;
1706 	unsigned int len;
1707 
1708 	portdev = container_of(work, struct ports_device, control_work);
1709 	vq = portdev->c_ivq;
1710 
1711 	spin_lock(&portdev->c_ivq_lock);
1712 	while ((buf = virtqueue_get_buf(vq, &len))) {
1713 		spin_unlock(&portdev->c_ivq_lock);
1714 
1715 		buf->len = len;
1716 		buf->offset = 0;
1717 
1718 		handle_control_message(vq->vdev, portdev, buf);
1719 
1720 		spin_lock(&portdev->c_ivq_lock);
1721 		if (add_inbuf(portdev->c_ivq, buf) < 0) {
1722 			dev_warn(&portdev->vdev->dev,
1723 				 "Error adding buffer to queue\n");
1724 			free_buf(buf, false);
1725 		}
1726 	}
1727 	spin_unlock(&portdev->c_ivq_lock);
1728 }
1729 
1730 static void flush_bufs(struct virtqueue *vq, bool can_sleep)
1731 {
1732 	struct port_buffer *buf;
1733 	unsigned int len;
1734 
1735 	while ((buf = virtqueue_get_buf(vq, &len)))
1736 		free_buf(buf, can_sleep);
1737 }
1738 
1739 static void out_intr(struct virtqueue *vq)
1740 {
1741 	struct port *port;
1742 
1743 	port = find_port_by_vq(vq->vdev->priv, vq);
1744 	if (!port) {
1745 		flush_bufs(vq, false);
1746 		return;
1747 	}
1748 
1749 	wake_up_interruptible(&port->waitqueue);
1750 }
1751 
1752 static void in_intr(struct virtqueue *vq)
1753 {
1754 	struct port *port;
1755 	unsigned long flags;
1756 
1757 	port = find_port_by_vq(vq->vdev->priv, vq);
1758 	if (!port) {
1759 		flush_bufs(vq, false);
1760 		return;
1761 	}
1762 
1763 	spin_lock_irqsave(&port->inbuf_lock, flags);
1764 	port->inbuf = get_inbuf(port);
1765 
1766 	/*
1767 	 * Normally the port should not accept data when the port is
1768 	 * closed. For generic serial ports, the host won't (shouldn't)
1769 	 * send data till the guest is connected. But this condition
1770 	 * can be reached when a console port is not yet connected (no
1771 	 * tty is spawned) and the other side sends out data over the
1772 	 * vring, or when a remote devices start sending data before
1773 	 * the ports are opened.
1774 	 *
1775 	 * A generic serial port will discard data if not connected,
1776 	 * while console ports and rproc-serial ports accepts data at
1777 	 * any time. rproc-serial is initiated with guest_connected to
1778 	 * false because port_fops_open expects this. Console ports are
1779 	 * hooked up with an HVC console and is initialized with
1780 	 * guest_connected to true.
1781 	 */
1782 
1783 	if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1784 		discard_port_data(port);
1785 
1786 	/* Send a SIGIO indicating new data in case the process asked for it */
1787 	send_sigio_to_port(port);
1788 
1789 	spin_unlock_irqrestore(&port->inbuf_lock, flags);
1790 
1791 	wake_up_interruptible(&port->waitqueue);
1792 
1793 	if (is_console_port(port) && hvc_poll(port->cons.hvc))
1794 		hvc_kick();
1795 }
1796 
1797 static void control_intr(struct virtqueue *vq)
1798 {
1799 	struct ports_device *portdev;
1800 
1801 	portdev = vq->vdev->priv;
1802 	schedule_work(&portdev->control_work);
1803 }
1804 
1805 static void config_intr(struct virtio_device *vdev)
1806 {
1807 	struct ports_device *portdev;
1808 
1809 	portdev = vdev->priv;
1810 
1811 	if (!use_multiport(portdev))
1812 		schedule_work(&portdev->config_work);
1813 }
1814 
1815 static void config_work_handler(struct work_struct *work)
1816 {
1817 	struct ports_device *portdev;
1818 
1819 	portdev = container_of(work, struct ports_device, config_work);
1820 	if (!use_multiport(portdev)) {
1821 		struct virtio_device *vdev;
1822 		struct port *port;
1823 		u16 rows, cols;
1824 
1825 		vdev = portdev->vdev;
1826 		virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1827 		virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1828 
1829 		port = find_port_by_id(portdev, 0);
1830 		set_console_size(port, rows, cols);
1831 
1832 		/*
1833 		 * We'll use this way of resizing only for legacy
1834 		 * support.  For newer userspace
1835 		 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1836 		 * to indicate console size changes so that it can be
1837 		 * done per-port.
1838 		 */
1839 		resize_console(port);
1840 	}
1841 }
1842 
1843 static int init_vqs(struct ports_device *portdev)
1844 {
1845 	vq_callback_t **io_callbacks;
1846 	char **io_names;
1847 	struct virtqueue **vqs;
1848 	u32 i, j, nr_ports, nr_queues;
1849 	int err;
1850 
1851 	nr_ports = portdev->max_nr_ports;
1852 	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1853 
1854 	vqs = kmalloc_array(nr_queues, sizeof(struct virtqueue *), GFP_KERNEL);
1855 	io_callbacks = kmalloc_array(nr_queues, sizeof(vq_callback_t *),
1856 				     GFP_KERNEL);
1857 	io_names = kmalloc_array(nr_queues, sizeof(char *), GFP_KERNEL);
1858 	portdev->in_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1859 					GFP_KERNEL);
1860 	portdev->out_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1861 					 GFP_KERNEL);
1862 	if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1863 	    !portdev->out_vqs) {
1864 		err = -ENOMEM;
1865 		goto free;
1866 	}
1867 
1868 	/*
1869 	 * For backward compat (newer host but older guest), the host
1870 	 * spawns a console port first and also inits the vqs for port
1871 	 * 0 before others.
1872 	 */
1873 	j = 0;
1874 	io_callbacks[j] = in_intr;
1875 	io_callbacks[j + 1] = out_intr;
1876 	io_names[j] = "input";
1877 	io_names[j + 1] = "output";
1878 	j += 2;
1879 
1880 	if (use_multiport(portdev)) {
1881 		io_callbacks[j] = control_intr;
1882 		io_callbacks[j + 1] = NULL;
1883 		io_names[j] = "control-i";
1884 		io_names[j + 1] = "control-o";
1885 
1886 		for (i = 1; i < nr_ports; i++) {
1887 			j += 2;
1888 			io_callbacks[j] = in_intr;
1889 			io_callbacks[j + 1] = out_intr;
1890 			io_names[j] = "input";
1891 			io_names[j + 1] = "output";
1892 		}
1893 	}
1894 	/* Find the queues. */
1895 	err = virtio_find_vqs(portdev->vdev, nr_queues, vqs,
1896 			      io_callbacks,
1897 			      (const char **)io_names, NULL);
1898 	if (err)
1899 		goto free;
1900 
1901 	j = 0;
1902 	portdev->in_vqs[0] = vqs[0];
1903 	portdev->out_vqs[0] = vqs[1];
1904 	j += 2;
1905 	if (use_multiport(portdev)) {
1906 		portdev->c_ivq = vqs[j];
1907 		portdev->c_ovq = vqs[j + 1];
1908 
1909 		for (i = 1; i < nr_ports; i++) {
1910 			j += 2;
1911 			portdev->in_vqs[i] = vqs[j];
1912 			portdev->out_vqs[i] = vqs[j + 1];
1913 		}
1914 	}
1915 	kfree(io_names);
1916 	kfree(io_callbacks);
1917 	kfree(vqs);
1918 
1919 	return 0;
1920 
1921 free:
1922 	kfree(portdev->out_vqs);
1923 	kfree(portdev->in_vqs);
1924 	kfree(io_names);
1925 	kfree(io_callbacks);
1926 	kfree(vqs);
1927 
1928 	return err;
1929 }
1930 
1931 static const struct file_operations portdev_fops = {
1932 	.owner = THIS_MODULE,
1933 };
1934 
1935 static void remove_vqs(struct ports_device *portdev)
1936 {
1937 	struct virtqueue *vq;
1938 
1939 	virtio_device_for_each_vq(portdev->vdev, vq) {
1940 		struct port_buffer *buf;
1941 
1942 		flush_bufs(vq, true);
1943 		while ((buf = virtqueue_detach_unused_buf(vq)))
1944 			free_buf(buf, true);
1945 	}
1946 	portdev->vdev->config->del_vqs(portdev->vdev);
1947 	kfree(portdev->in_vqs);
1948 	kfree(portdev->out_vqs);
1949 }
1950 
1951 static void virtcons_remove(struct virtio_device *vdev)
1952 {
1953 	struct ports_device *portdev;
1954 	struct port *port, *port2;
1955 
1956 	portdev = vdev->priv;
1957 
1958 	spin_lock_irq(&pdrvdata_lock);
1959 	list_del(&portdev->list);
1960 	spin_unlock_irq(&pdrvdata_lock);
1961 
1962 	/* Disable interrupts for vqs */
1963 	vdev->config->reset(vdev);
1964 	/* Finish up work that's lined up */
1965 	if (use_multiport(portdev))
1966 		cancel_work_sync(&portdev->control_work);
1967 	else
1968 		cancel_work_sync(&portdev->config_work);
1969 
1970 	list_for_each_entry_safe(port, port2, &portdev->ports, list)
1971 		unplug_port(port);
1972 
1973 	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1974 
1975 	/*
1976 	 * When yanking out a device, we immediately lose the
1977 	 * (device-side) queues.  So there's no point in keeping the
1978 	 * guest side around till we drop our final reference.  This
1979 	 * also means that any ports which are in an open state will
1980 	 * have to just stop using the port, as the vqs are going
1981 	 * away.
1982 	 */
1983 	remove_vqs(portdev);
1984 	kfree(portdev);
1985 }
1986 
1987 /*
1988  * Once we're further in boot, we get probed like any other virtio
1989  * device.
1990  *
1991  * If the host also supports multiple console ports, we check the
1992  * config space to see how many ports the host has spawned.  We
1993  * initialize each port found.
1994  */
1995 static int virtcons_probe(struct virtio_device *vdev)
1996 {
1997 	struct ports_device *portdev;
1998 	int err;
1999 	bool multiport;
2000 	bool early = early_put_chars != NULL;
2001 
2002 	/* We only need a config space if features are offered */
2003 	if (!vdev->config->get &&
2004 	    (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
2005 	     || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
2006 		dev_err(&vdev->dev, "%s failure: config access disabled\n",
2007 			__func__);
2008 		return -EINVAL;
2009 	}
2010 
2011 	/* Ensure to read early_put_chars now */
2012 	barrier();
2013 
2014 	portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
2015 	if (!portdev) {
2016 		err = -ENOMEM;
2017 		goto fail;
2018 	}
2019 
2020 	/* Attach this portdev to this virtio_device, and vice-versa. */
2021 	portdev->vdev = vdev;
2022 	vdev->priv = portdev;
2023 
2024 	portdev->chr_major = register_chrdev(0, "virtio-portsdev",
2025 					     &portdev_fops);
2026 	if (portdev->chr_major < 0) {
2027 		dev_err(&vdev->dev,
2028 			"Error %d registering chrdev for device %u\n",
2029 			portdev->chr_major, vdev->index);
2030 		err = portdev->chr_major;
2031 		goto free;
2032 	}
2033 
2034 	multiport = false;
2035 	portdev->max_nr_ports = 1;
2036 
2037 	/* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2038 	if (!is_rproc_serial(vdev) &&
2039 	    virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2040 				 struct virtio_console_config, max_nr_ports,
2041 				 &portdev->max_nr_ports) == 0) {
2042 		multiport = true;
2043 	}
2044 
2045 	err = init_vqs(portdev);
2046 	if (err < 0) {
2047 		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2048 		goto free_chrdev;
2049 	}
2050 
2051 	spin_lock_init(&portdev->ports_lock);
2052 	INIT_LIST_HEAD(&portdev->ports);
2053 	INIT_LIST_HEAD(&portdev->list);
2054 
2055 	virtio_device_ready(portdev->vdev);
2056 
2057 	INIT_WORK(&portdev->config_work, &config_work_handler);
2058 	INIT_WORK(&portdev->control_work, &control_work_handler);
2059 
2060 	if (multiport) {
2061 		spin_lock_init(&portdev->c_ivq_lock);
2062 		spin_lock_init(&portdev->c_ovq_lock);
2063 
2064 		err = fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2065 		if (err < 0) {
2066 			dev_err(&vdev->dev,
2067 				"Error allocating buffers for control queue\n");
2068 			/*
2069 			 * The host might want to notify mgmt sw about device
2070 			 * add failure.
2071 			 */
2072 			__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2073 					   VIRTIO_CONSOLE_DEVICE_READY, 0);
2074 			/* Device was functional: we need full cleanup. */
2075 			virtcons_remove(vdev);
2076 			return err;
2077 		}
2078 	} else {
2079 		/*
2080 		 * For backward compatibility: Create a console port
2081 		 * if we're running on older host.
2082 		 */
2083 		add_port(portdev, 0);
2084 	}
2085 
2086 	spin_lock_irq(&pdrvdata_lock);
2087 	list_add_tail(&portdev->list, &pdrvdata.portdevs);
2088 	spin_unlock_irq(&pdrvdata_lock);
2089 
2090 	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2091 			   VIRTIO_CONSOLE_DEVICE_READY, 1);
2092 
2093 	/*
2094 	 * If there was an early virtio console, assume that there are no
2095 	 * other consoles. We need to wait until the hvc_alloc matches the
2096 	 * hvc_instantiate, otherwise tty_open will complain, resulting in
2097 	 * a "Warning: unable to open an initial console" boot failure.
2098 	 * Without multiport this is done in add_port above. With multiport
2099 	 * this might take some host<->guest communication - thus we have to
2100 	 * wait.
2101 	 */
2102 	if (multiport && early)
2103 		wait_for_completion(&early_console_added);
2104 
2105 	return 0;
2106 
2107 free_chrdev:
2108 	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2109 free:
2110 	kfree(portdev);
2111 fail:
2112 	return err;
2113 }
2114 
2115 static const struct virtio_device_id id_table[] = {
2116 	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2117 	{ 0 },
2118 };
2119 MODULE_DEVICE_TABLE(virtio, id_table);
2120 
2121 static const unsigned int features[] = {
2122 	VIRTIO_CONSOLE_F_SIZE,
2123 	VIRTIO_CONSOLE_F_MULTIPORT,
2124 };
2125 
2126 static const struct virtio_device_id rproc_serial_id_table[] = {
2127 #if IS_ENABLED(CONFIG_REMOTEPROC)
2128 	{ VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2129 #endif
2130 	{ 0 },
2131 };
2132 MODULE_DEVICE_TABLE(virtio, rproc_serial_id_table);
2133 
2134 static const unsigned int rproc_serial_features[] = {
2135 };
2136 
2137 #ifdef CONFIG_PM_SLEEP
2138 static int virtcons_freeze(struct virtio_device *vdev)
2139 {
2140 	struct ports_device *portdev;
2141 	struct port *port;
2142 
2143 	portdev = vdev->priv;
2144 
2145 	vdev->config->reset(vdev);
2146 
2147 	if (use_multiport(portdev))
2148 		virtqueue_disable_cb(portdev->c_ivq);
2149 	cancel_work_sync(&portdev->control_work);
2150 	cancel_work_sync(&portdev->config_work);
2151 	/*
2152 	 * Once more: if control_work_handler() was running, it would
2153 	 * enable the cb as the last step.
2154 	 */
2155 	if (use_multiport(portdev))
2156 		virtqueue_disable_cb(portdev->c_ivq);
2157 
2158 	list_for_each_entry(port, &portdev->ports, list) {
2159 		virtqueue_disable_cb(port->in_vq);
2160 		virtqueue_disable_cb(port->out_vq);
2161 		/*
2162 		 * We'll ask the host later if the new invocation has
2163 		 * the port opened or closed.
2164 		 */
2165 		port->host_connected = false;
2166 		remove_port_data(port);
2167 	}
2168 	remove_vqs(portdev);
2169 
2170 	return 0;
2171 }
2172 
2173 static int virtcons_restore(struct virtio_device *vdev)
2174 {
2175 	struct ports_device *portdev;
2176 	struct port *port;
2177 	int ret;
2178 
2179 	portdev = vdev->priv;
2180 
2181 	ret = init_vqs(portdev);
2182 	if (ret)
2183 		return ret;
2184 
2185 	virtio_device_ready(portdev->vdev);
2186 
2187 	if (use_multiport(portdev))
2188 		fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2189 
2190 	list_for_each_entry(port, &portdev->ports, list) {
2191 		port->in_vq = portdev->in_vqs[port->id];
2192 		port->out_vq = portdev->out_vqs[port->id];
2193 
2194 		fill_queue(port->in_vq, &port->inbuf_lock);
2195 
2196 		/* Get port open/close status on the host */
2197 		send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2198 
2199 		/*
2200 		 * If a port was open at the time of suspending, we
2201 		 * have to let the host know that it's still open.
2202 		 */
2203 		if (port->guest_connected)
2204 			send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2205 	}
2206 	return 0;
2207 }
2208 #endif
2209 
2210 static struct virtio_driver virtio_console = {
2211 	.feature_table = features,
2212 	.feature_table_size = ARRAY_SIZE(features),
2213 	.driver.name =	KBUILD_MODNAME,
2214 	.driver.owner =	THIS_MODULE,
2215 	.id_table =	id_table,
2216 	.probe =	virtcons_probe,
2217 	.remove =	virtcons_remove,
2218 	.config_changed = config_intr,
2219 #ifdef CONFIG_PM_SLEEP
2220 	.freeze =	virtcons_freeze,
2221 	.restore =	virtcons_restore,
2222 #endif
2223 };
2224 
2225 static struct virtio_driver virtio_rproc_serial = {
2226 	.feature_table = rproc_serial_features,
2227 	.feature_table_size = ARRAY_SIZE(rproc_serial_features),
2228 	.driver.name =	"virtio_rproc_serial",
2229 	.driver.owner =	THIS_MODULE,
2230 	.id_table =	rproc_serial_id_table,
2231 	.probe =	virtcons_probe,
2232 	.remove =	virtcons_remove,
2233 };
2234 
2235 static int __init init(void)
2236 {
2237 	int err;
2238 
2239 	pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
2240 	if (IS_ERR(pdrvdata.class)) {
2241 		err = PTR_ERR(pdrvdata.class);
2242 		pr_err("Error %d creating virtio-ports class\n", err);
2243 		return err;
2244 	}
2245 
2246 	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
2247 	if (!pdrvdata.debugfs_dir)
2248 		pr_warn("Error creating debugfs dir for virtio-ports\n");
2249 	INIT_LIST_HEAD(&pdrvdata.consoles);
2250 	INIT_LIST_HEAD(&pdrvdata.portdevs);
2251 
2252 	err = register_virtio_driver(&virtio_console);
2253 	if (err < 0) {
2254 		pr_err("Error %d registering virtio driver\n", err);
2255 		goto free;
2256 	}
2257 	err = register_virtio_driver(&virtio_rproc_serial);
2258 	if (err < 0) {
2259 		pr_err("Error %d registering virtio rproc serial driver\n",
2260 		       err);
2261 		goto unregister;
2262 	}
2263 	return 0;
2264 unregister:
2265 	unregister_virtio_driver(&virtio_console);
2266 free:
2267 	debugfs_remove_recursive(pdrvdata.debugfs_dir);
2268 	class_destroy(pdrvdata.class);
2269 	return err;
2270 }
2271 
2272 static void __exit fini(void)
2273 {
2274 	reclaim_dma_bufs();
2275 
2276 	unregister_virtio_driver(&virtio_console);
2277 	unregister_virtio_driver(&virtio_rproc_serial);
2278 
2279 	class_destroy(pdrvdata.class);
2280 	debugfs_remove_recursive(pdrvdata.debugfs_dir);
2281 }
2282 module_init(init);
2283 module_exit(fini);
2284 
2285 MODULE_DESCRIPTION("Virtio console driver");
2286 MODULE_LICENSE("GPL");
2287