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/idr.h>
  17#include <linux/init.h>
  18#include <linux/list.h>
  19#include <linux/poll.h>
  20#include <linux/sched.h>
  21#include <linux/slab.h>
  22#include <linux/spinlock.h>
  23#include <linux/virtio.h>
  24#include <linux/virtio_console.h>
  25#include <linux/wait.h>
  26#include <linux/workqueue.h>
  27#include <linux/module.h>
  28#include <linux/dma-mapping.h>
  29#include "../tty/hvc/hvc_console.h"
  30
  31#define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
  32#define VIRTCONS_MAX_PORTS 0x8000
  33
  34/*
  35 * This is a global struct for storing common data for all the devices
  36 * this driver handles.
  37 *
  38 * Mainly, it has a linked list for all the consoles in one place so
  39 * that callbacks from hvc for get_chars(), put_chars() work properly
  40 * across multiple devices and multiple ports per device.
  41 */
  42struct ports_driver_data {
 
 
 
  43	/* Used for exporting per-port information to debugfs */
  44	struct dentry *debugfs_dir;
  45
  46	/* List of all the devices we're handling */
  47	struct list_head portdevs;
  48
 
 
 
 
 
 
 
 
 
 
 
 
  49	/* All the console devices handled by this driver */
  50	struct list_head consoles;
  51};
  52
  53static struct ports_driver_data pdrvdata;
  54
  55static const struct class port_class = {
  56	.name = "virtio-ports",
  57};
  58
  59static DEFINE_SPINLOCK(pdrvdata_lock);
  60static DECLARE_COMPLETION(early_console_added);
  61
  62/* This struct holds information that's relevant only for console ports */
  63struct console {
  64	/* We'll place all consoles in a list in the pdrvdata struct */
  65	struct list_head list;
  66
  67	/* The hvc device associated with this console port */
  68	struct hvc_struct *hvc;
  69
  70	/* The size of the console */
  71	struct winsize ws;
  72
  73	/*
  74	 * This number identifies the number that we used to register
  75	 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
  76	 * number passed on by the hvc callbacks to us to
  77	 * differentiate between the other console ports handled by
  78	 * this driver
  79	 */
  80	u32 vtermno;
  81};
  82
  83static DEFINE_IDA(vtermno_ida);
  84
  85struct port_buffer {
  86	char *buf;
  87
  88	/* size of the buffer in *buf above */
  89	size_t size;
  90
  91	/* used length of the buffer */
  92	size_t len;
  93	/* offset in the buf from which to consume data */
  94	size_t offset;
  95
  96	/* DMA address of buffer */
  97	dma_addr_t dma;
  98
  99	/* Device we got DMA memory from */
 100	struct device *dev;
 101
 102	/* List of pending dma buffers to free */
 103	struct list_head list;
 104
 105	/* If sgpages == 0 then buf is used */
 106	unsigned int sgpages;
 107
 108	/* sg is used if spages > 0. sg must be the last in is struct */
 109	struct scatterlist sg[] __counted_by(sgpages);
 110};
 111
 112/*
 113 * This is a per-device struct that stores data common to all the
 114 * ports for that device (vdev->priv).
 115 */
 116struct ports_device {
 117	/* Next portdev in the list, head is in the pdrvdata struct */
 118	struct list_head list;
 119
 120	/*
 121	 * Workqueue handlers where we process deferred work after
 122	 * notification
 123	 */
 124	struct work_struct control_work;
 125	struct work_struct config_work;
 126
 127	struct list_head ports;
 128
 129	/* To protect the list of ports */
 130	spinlock_t ports_lock;
 131
 132	/* To protect the vq operations for the control channel */
 133	spinlock_t c_ivq_lock;
 134	spinlock_t c_ovq_lock;
 135
 136	/* max. number of ports this device can hold */
 137	u32 max_nr_ports;
 138
 139	/* The virtio device we're associated with */
 140	struct virtio_device *vdev;
 141
 142	/*
 143	 * A couple of virtqueues for the control channel: one for
 144	 * guest->host transfers, one for host->guest transfers
 145	 */
 146	struct virtqueue *c_ivq, *c_ovq;
 147
 148	/*
 149	 * A control packet buffer for guest->host requests, protected
 150	 * by c_ovq_lock.
 151	 */
 152	struct virtio_console_control cpkt;
 153
 154	/* Array of per-port IO virtqueues */
 155	struct virtqueue **in_vqs, **out_vqs;
 156
 157	/* Major number for this device.  Ports will be created as minors. */
 158	int chr_major;
 159};
 160
 161struct port_stats {
 162	unsigned long bytes_sent, bytes_received, bytes_discarded;
 163};
 164
 165/* This struct holds the per-port data */
 166struct port {
 167	/* Next port in the list, head is in the ports_device */
 168	struct list_head list;
 169
 170	/* Pointer to the parent virtio_console device */
 171	struct ports_device *portdev;
 172
 173	/* The current buffer from which data has to be fed to readers */
 174	struct port_buffer *inbuf;
 175
 176	/*
 177	 * To protect the operations on the in_vq associated with this
 178	 * port.  Has to be a spinlock because it can be called from
 179	 * interrupt context (get_char()).
 180	 */
 181	spinlock_t inbuf_lock;
 182
 183	/* Protect the operations on the out_vq. */
 184	spinlock_t outvq_lock;
 185
 186	/* The IO vqs for this port */
 187	struct virtqueue *in_vq, *out_vq;
 188
 189	/* File in the debugfs directory that exposes this port's information */
 190	struct dentry *debugfs_file;
 191
 192	/*
 193	 * Keep count of the bytes sent, received and discarded for
 194	 * this port for accounting and debugging purposes.  These
 195	 * counts are not reset across port open / close events.
 196	 */
 197	struct port_stats stats;
 198
 199	/*
 200	 * The entries in this struct will be valid if this port is
 201	 * hooked up to an hvc console
 202	 */
 203	struct console cons;
 204
 205	/* Each port associates with a separate char device */
 206	struct cdev *cdev;
 207	struct device *dev;
 208
 209	/* Reference-counting to handle port hot-unplugs and file operations */
 210	struct kref kref;
 211
 212	/* A waitqueue for poll() or blocking read operations */
 213	wait_queue_head_t waitqueue;
 214
 215	/* The 'name' of the port that we expose via sysfs properties */
 216	char *name;
 217
 218	/* We can notify apps of host connect / disconnect events via SIGIO */
 219	struct fasync_struct *async_queue;
 220
 221	/* The 'id' to identify the port with the Host */
 222	u32 id;
 223
 224	bool outvq_full;
 225
 226	/* Is the host device open */
 227	bool host_connected;
 228
 229	/* We should allow only one process to open a port */
 230	bool guest_connected;
 231};
 232
 
 
 
 233static struct port *find_port_by_vtermno(u32 vtermno)
 234{
 235	struct port *port;
 236	struct console *cons;
 237	unsigned long flags;
 238
 239	spin_lock_irqsave(&pdrvdata_lock, flags);
 240	list_for_each_entry(cons, &pdrvdata.consoles, list) {
 241		if (cons->vtermno == vtermno) {
 242			port = container_of(cons, struct port, cons);
 243			goto out;
 244		}
 245	}
 246	port = NULL;
 247out:
 248	spin_unlock_irqrestore(&pdrvdata_lock, flags);
 249	return port;
 250}
 251
 252static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
 253						 dev_t dev)
 254{
 255	struct port *port;
 256	unsigned long flags;
 257
 258	spin_lock_irqsave(&portdev->ports_lock, flags);
 259	list_for_each_entry(port, &portdev->ports, list) {
 260		if (port->cdev->dev == dev) {
 261			kref_get(&port->kref);
 262			goto out;
 263		}
 264	}
 265	port = NULL;
 266out:
 267	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 268
 269	return port;
 270}
 271
 272static struct port *find_port_by_devt(dev_t dev)
 273{
 274	struct ports_device *portdev;
 275	struct port *port;
 276	unsigned long flags;
 277
 278	spin_lock_irqsave(&pdrvdata_lock, flags);
 279	list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
 280		port = find_port_by_devt_in_portdev(portdev, dev);
 281		if (port)
 282			goto out;
 283	}
 284	port = NULL;
 285out:
 286	spin_unlock_irqrestore(&pdrvdata_lock, flags);
 287	return port;
 288}
 289
 290static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 291{
 292	struct port *port;
 293	unsigned long flags;
 294
 295	spin_lock_irqsave(&portdev->ports_lock, flags);
 296	list_for_each_entry(port, &portdev->ports, list)
 297		if (port->id == id)
 298			goto out;
 299	port = NULL;
 300out:
 301	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 302
 303	return port;
 304}
 305
 306static struct port *find_port_by_vq(struct ports_device *portdev,
 307				    struct virtqueue *vq)
 308{
 309	struct port *port;
 310	unsigned long flags;
 311
 312	spin_lock_irqsave(&portdev->ports_lock, flags);
 313	list_for_each_entry(port, &portdev->ports, list)
 314		if (port->in_vq == vq || port->out_vq == vq)
 315			goto out;
 316	port = NULL;
 317out:
 318	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 319	return port;
 320}
 321
 322static bool is_console_port(struct port *port)
 323{
 324	if (port->cons.hvc)
 325		return true;
 326	return false;
 327}
 328
 329static bool is_rproc_serial(const struct virtio_device *vdev)
 330{
 331	return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
 332}
 333
 334static inline bool use_multiport(struct ports_device *portdev)
 335{
 336	/*
 337	 * This condition can be true when put_chars is called from
 338	 * early_init
 339	 */
 340	if (!portdev->vdev)
 341		return false;
 342	return __virtio_test_bit(portdev->vdev, VIRTIO_CONSOLE_F_MULTIPORT);
 343}
 344
 345static DEFINE_SPINLOCK(dma_bufs_lock);
 346static LIST_HEAD(pending_free_dma_bufs);
 347
 348static void free_buf(struct port_buffer *buf, bool can_sleep)
 349{
 350	unsigned int i;
 351
 352	for (i = 0; i < buf->sgpages; i++) {
 353		struct page *page = sg_page(&buf->sg[i]);
 354		if (!page)
 355			break;
 356		put_page(page);
 357	}
 358
 359	if (!buf->dev) {
 360		kfree(buf->buf);
 361	} else if (is_rproc_enabled) {
 362		unsigned long flags;
 363
 364		/* dma_free_coherent requires interrupts to be enabled. */
 365		if (!can_sleep) {
 366			/* queue up dma-buffers to be freed later */
 367			spin_lock_irqsave(&dma_bufs_lock, flags);
 368			list_add_tail(&buf->list, &pending_free_dma_bufs);
 369			spin_unlock_irqrestore(&dma_bufs_lock, flags);
 370			return;
 371		}
 372		dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
 373
 374		/* Release device refcnt and allow it to be freed */
 375		put_device(buf->dev);
 376	}
 377
 378	kfree(buf);
 379}
 380
 381static void reclaim_dma_bufs(void)
 382{
 383	unsigned long flags;
 384	struct port_buffer *buf, *tmp;
 385	LIST_HEAD(tmp_list);
 386
 387	if (list_empty(&pending_free_dma_bufs))
 388		return;
 389
 390	/* Create a copy of the pending_free_dma_bufs while holding the lock */
 391	spin_lock_irqsave(&dma_bufs_lock, flags);
 392	list_cut_position(&tmp_list, &pending_free_dma_bufs,
 393			  pending_free_dma_bufs.prev);
 394	spin_unlock_irqrestore(&dma_bufs_lock, flags);
 395
 396	/* Release the dma buffers, without irqs enabled */
 397	list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
 398		list_del(&buf->list);
 399		free_buf(buf, true);
 400	}
 401}
 402
 403static struct port_buffer *alloc_buf(struct virtio_device *vdev, size_t buf_size,
 404				     int pages)
 405{
 406	struct port_buffer *buf;
 407
 408	reclaim_dma_bufs();
 409
 410	/*
 411	 * Allocate buffer and the sg list. The sg list array is allocated
 412	 * directly after the port_buffer struct.
 413	 */
 414	buf = kmalloc(struct_size(buf, sg, pages), GFP_KERNEL);
 415	if (!buf)
 416		goto fail;
 417
 418	buf->sgpages = pages;
 419	if (pages > 0) {
 420		buf->dev = NULL;
 421		buf->buf = NULL;
 422		return buf;
 423	}
 424
 425	if (is_rproc_serial(vdev)) {
 426		/*
 427		 * Allocate DMA memory from ancestor. When a virtio
 428		 * device is created by remoteproc, the DMA memory is
 429		 * associated with the parent device:
 430		 * virtioY => remoteprocX#vdevYbuffer.
 431		 */
 432		buf->dev = vdev->dev.parent;
 433		if (!buf->dev)
 434			goto free_buf;
 
 435
 436		/* Increase device refcnt to avoid freeing it */
 437		get_device(buf->dev);
 438		buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
 439					      GFP_KERNEL);
 440	} else {
 441		buf->dev = NULL;
 442		buf->buf = kmalloc(buf_size, GFP_KERNEL);
 443	}
 444
 445	if (!buf->buf)
 446		goto free_buf;
 447	buf->len = 0;
 448	buf->offset = 0;
 449	buf->size = buf_size;
 450	return buf;
 451
 452free_buf:
 453	kfree(buf);
 454fail:
 455	return NULL;
 456}
 457
 458/* Callers should take appropriate locks */
 459static struct port_buffer *get_inbuf(struct port *port)
 460{
 461	struct port_buffer *buf;
 462	unsigned int len;
 463
 464	if (port->inbuf)
 465		return port->inbuf;
 466
 467	buf = virtqueue_get_buf(port->in_vq, &len);
 468	if (buf) {
 469		buf->len = min_t(size_t, len, buf->size);
 470		buf->offset = 0;
 471		port->stats.bytes_received += len;
 472	}
 473	return buf;
 474}
 475
 476/*
 477 * Create a scatter-gather list representing our input buffer and put
 478 * it in the queue.
 479 *
 480 * Callers should take appropriate locks.
 481 */
 482static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 483{
 484	struct scatterlist sg[1];
 485	int ret;
 486
 487	sg_init_one(sg, buf->buf, buf->size);
 488
 489	ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC);
 490	virtqueue_kick(vq);
 491	if (!ret)
 492		ret = vq->num_free;
 493	return ret;
 494}
 495
 496/* Discard any unread data this port has. Callers lockers. */
 497static void discard_port_data(struct port *port)
 498{
 499	struct port_buffer *buf;
 500	unsigned int err;
 501
 502	if (!port->portdev) {
 503		/* Device has been unplugged.  vqs are already gone. */
 504		return;
 505	}
 506	buf = get_inbuf(port);
 507
 508	err = 0;
 509	while (buf) {
 510		port->stats.bytes_discarded += buf->len - buf->offset;
 511		if (add_inbuf(port->in_vq, buf) < 0) {
 512			err++;
 513			free_buf(buf, false);
 514		}
 515		port->inbuf = NULL;
 516		buf = get_inbuf(port);
 517	}
 518	if (err)
 519		dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
 520			 err);
 521}
 522
 523static bool port_has_data(struct port *port)
 524{
 525	unsigned long flags;
 526	bool ret;
 527
 528	ret = false;
 529	spin_lock_irqsave(&port->inbuf_lock, flags);
 530	port->inbuf = get_inbuf(port);
 531	if (port->inbuf)
 532		ret = true;
 533
 534	spin_unlock_irqrestore(&port->inbuf_lock, flags);
 535	return ret;
 536}
 537
 538static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
 539				  unsigned int event, unsigned int value)
 540{
 541	struct scatterlist sg[1];
 542	struct virtqueue *vq;
 543	unsigned int len;
 544
 545	if (!use_multiport(portdev))
 546		return 0;
 547
 548	vq = portdev->c_ovq;
 549
 550	spin_lock(&portdev->c_ovq_lock);
 551
 552	portdev->cpkt.id = cpu_to_virtio32(portdev->vdev, port_id);
 553	portdev->cpkt.event = cpu_to_virtio16(portdev->vdev, event);
 554	portdev->cpkt.value = cpu_to_virtio16(portdev->vdev, value);
 555
 556	sg_init_one(sg, &portdev->cpkt, sizeof(struct virtio_console_control));
 557
 558	if (virtqueue_add_outbuf(vq, sg, 1, &portdev->cpkt, GFP_ATOMIC) == 0) {
 559		virtqueue_kick(vq);
 560		while (!virtqueue_get_buf(vq, &len)
 561			&& !virtqueue_is_broken(vq))
 562			cpu_relax();
 563	}
 564
 565	spin_unlock(&portdev->c_ovq_lock);
 566	return 0;
 567}
 568
 569static ssize_t send_control_msg(struct port *port, unsigned int event,
 570				unsigned int value)
 571{
 572	/* Did the port get unplugged before userspace closed it? */
 573	if (port->portdev)
 574		return __send_control_msg(port->portdev, port->id, event, value);
 575	return 0;
 576}
 577
 578
 579/* Callers must take the port->outvq_lock */
 580static void reclaim_consumed_buffers(struct port *port)
 581{
 582	struct port_buffer *buf;
 583	unsigned int len;
 584
 585	if (!port->portdev) {
 586		/* Device has been unplugged.  vqs are already gone. */
 587		return;
 588	}
 589	while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
 590		free_buf(buf, false);
 591		port->outvq_full = false;
 592	}
 593}
 594
 595static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
 596			      int nents, size_t in_count,
 597			      void *data, bool nonblock)
 598{
 599	struct virtqueue *out_vq;
 600	int err;
 601	unsigned long flags;
 602	unsigned int len;
 603
 604	out_vq = port->out_vq;
 605
 606	spin_lock_irqsave(&port->outvq_lock, flags);
 607
 608	reclaim_consumed_buffers(port);
 609
 610	err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
 611
 612	/* Tell Host to go! */
 613	virtqueue_kick(out_vq);
 614
 615	if (err) {
 616		in_count = 0;
 617		goto done;
 618	}
 619
 620	if (out_vq->num_free == 0)
 621		port->outvq_full = true;
 622
 623	if (nonblock)
 624		goto done;
 625
 626	/*
 627	 * Wait till the host acknowledges it pushed out the data we
 628	 * sent.  This is done for data from the hvc_console; the tty
 629	 * operations are performed with spinlocks held so we can't
 630	 * sleep here.  An alternative would be to copy the data to a
 631	 * buffer and relax the spinning requirement.  The downside is
 632	 * we need to kmalloc a GFP_ATOMIC buffer each time the
 633	 * console driver writes something out.
 634	 */
 635	while (!virtqueue_get_buf(out_vq, &len)
 636		&& !virtqueue_is_broken(out_vq))
 637		cpu_relax();
 638done:
 639	spin_unlock_irqrestore(&port->outvq_lock, flags);
 640
 641	port->stats.bytes_sent += in_count;
 642	/*
 643	 * We're expected to return the amount of data we wrote -- all
 644	 * of it
 645	 */
 646	return in_count;
 647}
 648
 649/*
 650 * Give out the data that's requested from the buffer that we have
 651 * queued up.
 652 */
 653static ssize_t fill_readbuf(struct port *port, u8 __user *out_buf,
 654			    size_t out_count, bool to_user)
 655{
 656	struct port_buffer *buf;
 657	unsigned long flags;
 658
 659	if (!out_count || !port_has_data(port))
 660		return 0;
 661
 662	buf = port->inbuf;
 663	out_count = min(out_count, buf->len - buf->offset);
 664
 665	if (to_user) {
 666		ssize_t ret;
 667
 668		ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
 669		if (ret)
 670			return -EFAULT;
 671	} else {
 672		memcpy((__force u8 *)out_buf, buf->buf + buf->offset,
 673		       out_count);
 674	}
 675
 676	buf->offset += out_count;
 677
 678	if (buf->offset == buf->len) {
 679		/*
 680		 * We're done using all the data in this buffer.
 681		 * Re-queue so that the Host can send us more data.
 682		 */
 683		spin_lock_irqsave(&port->inbuf_lock, flags);
 684		port->inbuf = NULL;
 685
 686		if (add_inbuf(port->in_vq, buf) < 0)
 687			dev_warn(port->dev, "failed add_buf\n");
 688
 689		spin_unlock_irqrestore(&port->inbuf_lock, flags);
 690	}
 691	/* Return the number of bytes actually copied */
 692	return out_count;
 693}
 694
 695/* The condition that must be true for polling to end */
 696static bool will_read_block(struct port *port)
 697{
 698	if (!port->guest_connected) {
 699		/* Port got hot-unplugged. Let's exit. */
 700		return false;
 701	}
 702	return !port_has_data(port) && port->host_connected;
 703}
 704
 705static bool will_write_block(struct port *port)
 706{
 707	bool ret;
 708
 709	if (!port->guest_connected) {
 710		/* Port got hot-unplugged. Let's exit. */
 711		return false;
 712	}
 713	if (!port->host_connected)
 714		return true;
 715
 716	spin_lock_irq(&port->outvq_lock);
 717	/*
 718	 * Check if the Host has consumed any buffers since we last
 719	 * sent data (this is only applicable for nonblocking ports).
 720	 */
 721	reclaim_consumed_buffers(port);
 722	ret = port->outvq_full;
 723	spin_unlock_irq(&port->outvq_lock);
 724
 725	return ret;
 726}
 727
 728static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
 729			      size_t count, loff_t *offp)
 730{
 731	struct port *port;
 732	ssize_t ret;
 733
 734	port = filp->private_data;
 735
 736	/* Port is hot-unplugged. */
 737	if (!port->guest_connected)
 738		return -ENODEV;
 739
 740	if (!port_has_data(port)) {
 741		/*
 742		 * If nothing's connected on the host just return 0 in
 743		 * case of list_empty; this tells the userspace app
 744		 * that there's no connection
 745		 */
 746		if (!port->host_connected)
 747			return 0;
 748		if (filp->f_flags & O_NONBLOCK)
 749			return -EAGAIN;
 750
 751		ret = wait_event_freezable(port->waitqueue,
 752					   !will_read_block(port));
 753		if (ret < 0)
 754			return ret;
 755	}
 756	/* Port got hot-unplugged while we were waiting above. */
 757	if (!port->guest_connected)
 758		return -ENODEV;
 759	/*
 760	 * We could've received a disconnection message while we were
 761	 * waiting for more data.
 762	 *
 763	 * This check is not clubbed in the if() statement above as we
 764	 * might receive some data as well as the host could get
 765	 * disconnected after we got woken up from our wait.  So we
 766	 * really want to give off whatever data we have and only then
 767	 * check for host_connected.
 768	 */
 769	if (!port_has_data(port) && !port->host_connected)
 770		return 0;
 771
 772	return fill_readbuf(port, ubuf, count, true);
 773}
 774
 775static int wait_port_writable(struct port *port, bool nonblock)
 776{
 777	int ret;
 778
 779	if (will_write_block(port)) {
 780		if (nonblock)
 781			return -EAGAIN;
 782
 783		ret = wait_event_freezable(port->waitqueue,
 784					   !will_write_block(port));
 785		if (ret < 0)
 786			return ret;
 787	}
 788	/* Port got hot-unplugged. */
 789	if (!port->guest_connected)
 790		return -ENODEV;
 791
 792	return 0;
 793}
 794
 795static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 796			       size_t count, loff_t *offp)
 797{
 798	struct port *port;
 799	struct port_buffer *buf;
 800	ssize_t ret;
 801	bool nonblock;
 802	struct scatterlist sg[1];
 803
 804	/* Userspace could be out to fool us */
 805	if (!count)
 806		return 0;
 807
 808	port = filp->private_data;
 809
 810	nonblock = filp->f_flags & O_NONBLOCK;
 811
 812	ret = wait_port_writable(port, nonblock);
 813	if (ret < 0)
 814		return ret;
 815
 816	count = min((size_t)(32 * 1024), count);
 817
 818	buf = alloc_buf(port->portdev->vdev, count, 0);
 819	if (!buf)
 820		return -ENOMEM;
 821
 822	ret = copy_from_user(buf->buf, ubuf, count);
 823	if (ret) {
 824		ret = -EFAULT;
 825		goto free_buf;
 826	}
 827
 828	/*
 829	 * We now ask send_buf() to not spin for generic ports -- we
 830	 * can re-use the same code path that non-blocking file
 831	 * descriptors take for blocking file descriptors since the
 832	 * wait is already done and we're certain the write will go
 833	 * through to the host.
 834	 */
 835	nonblock = true;
 836	sg_init_one(sg, buf->buf, count);
 837	ret = __send_to_port(port, sg, 1, count, buf, nonblock);
 838
 839	if (nonblock && ret > 0)
 840		goto out;
 841
 842free_buf:
 843	free_buf(buf, true);
 844out:
 845	return ret;
 846}
 847
 848struct sg_list {
 849	unsigned int n;
 850	unsigned int size;
 851	size_t len;
 852	struct scatterlist *sg;
 853};
 854
 855static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 856			struct splice_desc *sd)
 857{
 858	struct sg_list *sgl = sd->u.data;
 859	unsigned int offset, len;
 860
 861	if (sgl->n == sgl->size)
 862		return 0;
 863
 864	/* Try lock this page */
 865	if (pipe_buf_try_steal(pipe, buf)) {
 866		/* Get reference and unlock page for moving */
 867		get_page(buf->page);
 868		unlock_page(buf->page);
 869
 870		len = min(buf->len, sd->len);
 871		sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
 872	} else {
 873		/* Failback to copying a page */
 874		struct page *page = alloc_page(GFP_KERNEL);
 875		char *src;
 876
 877		if (!page)
 878			return -ENOMEM;
 879
 880		offset = sd->pos & ~PAGE_MASK;
 881
 882		len = sd->len;
 883		if (len + offset > PAGE_SIZE)
 884			len = PAGE_SIZE - offset;
 885
 886		src = kmap_atomic(buf->page);
 887		memcpy(page_address(page) + offset, src + buf->offset, len);
 888		kunmap_atomic(src);
 889
 890		sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
 891	}
 892	sgl->n++;
 893	sgl->len += len;
 894
 895	return len;
 896}
 897
 898/* Faster zero-copy write by splicing */
 899static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
 900				      struct file *filp, loff_t *ppos,
 901				      size_t len, unsigned int flags)
 902{
 903	struct port *port = filp->private_data;
 904	struct sg_list sgl;
 905	ssize_t ret;
 906	struct port_buffer *buf;
 907	struct splice_desc sd = {
 908		.total_len = len,
 909		.flags = flags,
 910		.pos = *ppos,
 911		.u.data = &sgl,
 912	};
 913	unsigned int occupancy;
 914
 915	/*
 916	 * Rproc_serial does not yet support splice. To support splice
 917	 * pipe_to_sg() must allocate dma-buffers and copy content from
 918	 * regular pages to dma pages. And alloc_buf and free_buf must
 919	 * support allocating and freeing such a list of dma-buffers.
 920	 */
 921	if (is_rproc_serial(port->out_vq->vdev))
 922		return -EINVAL;
 923
 924	pipe_lock(pipe);
 925	ret = 0;
 926	if (pipe_empty(pipe->head, pipe->tail))
 927		goto error_out;
 928
 929	ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
 930	if (ret < 0)
 931		goto error_out;
 932
 933	occupancy = pipe_occupancy(pipe->head, pipe->tail);
 934	buf = alloc_buf(port->portdev->vdev, 0, occupancy);
 935
 936	if (!buf) {
 937		ret = -ENOMEM;
 938		goto error_out;
 939	}
 940
 941	sgl.n = 0;
 942	sgl.len = 0;
 943	sgl.size = occupancy;
 944	sgl.sg = buf->sg;
 945	sg_init_table(sgl.sg, sgl.size);
 946	ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
 947	pipe_unlock(pipe);
 948	if (likely(ret > 0))
 949		ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
 950
 951	if (unlikely(ret <= 0))
 952		free_buf(buf, true);
 953	return ret;
 954
 955error_out:
 956	pipe_unlock(pipe);
 957	return ret;
 958}
 959
 960static __poll_t port_fops_poll(struct file *filp, poll_table *wait)
 961{
 962	struct port *port;
 963	__poll_t ret;
 964
 965	port = filp->private_data;
 966	poll_wait(filp, &port->waitqueue, wait);
 967
 968	if (!port->guest_connected) {
 969		/* Port got unplugged */
 970		return EPOLLHUP;
 971	}
 972	ret = 0;
 973	if (!will_read_block(port))
 974		ret |= EPOLLIN | EPOLLRDNORM;
 975	if (!will_write_block(port))
 976		ret |= EPOLLOUT;
 977	if (!port->host_connected)
 978		ret |= EPOLLHUP;
 979
 980	return ret;
 981}
 982
 983static void remove_port(struct kref *kref);
 984
 985static int port_fops_release(struct inode *inode, struct file *filp)
 986{
 987	struct port *port;
 988
 989	port = filp->private_data;
 990
 991	/* Notify host of port being closed */
 992	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 993
 994	spin_lock_irq(&port->inbuf_lock);
 995	port->guest_connected = false;
 996
 997	discard_port_data(port);
 998
 999	spin_unlock_irq(&port->inbuf_lock);
1000
1001	spin_lock_irq(&port->outvq_lock);
1002	reclaim_consumed_buffers(port);
1003	spin_unlock_irq(&port->outvq_lock);
1004
1005	reclaim_dma_bufs();
1006	/*
1007	 * Locks aren't necessary here as a port can't be opened after
1008	 * unplug, and if a port isn't unplugged, a kref would already
1009	 * exist for the port.  Plus, taking ports_lock here would
1010	 * create a dependency on other locks taken by functions
1011	 * inside remove_port if we're the last holder of the port,
1012	 * creating many problems.
1013	 */
1014	kref_put(&port->kref, remove_port);
1015
1016	return 0;
1017}
1018
1019static int port_fops_open(struct inode *inode, struct file *filp)
1020{
1021	struct cdev *cdev = inode->i_cdev;
1022	struct port *port;
1023	int ret;
1024
1025	/* We get the port with a kref here */
1026	port = find_port_by_devt(cdev->dev);
1027	if (!port) {
1028		/* Port was unplugged before we could proceed */
1029		return -ENXIO;
1030	}
1031	filp->private_data = port;
1032
1033	/*
1034	 * Don't allow opening of console port devices -- that's done
1035	 * via /dev/hvc
1036	 */
1037	if (is_console_port(port)) {
1038		ret = -ENXIO;
1039		goto out;
1040	}
1041
1042	/* Allow only one process to open a particular port at a time */
1043	spin_lock_irq(&port->inbuf_lock);
1044	if (port->guest_connected) {
1045		spin_unlock_irq(&port->inbuf_lock);
1046		ret = -EBUSY;
1047		goto out;
1048	}
1049
1050	port->guest_connected = true;
1051	spin_unlock_irq(&port->inbuf_lock);
1052
1053	spin_lock_irq(&port->outvq_lock);
1054	/*
1055	 * There might be a chance that we missed reclaiming a few
1056	 * buffers in the window of the port getting previously closed
1057	 * and opening now.
1058	 */
1059	reclaim_consumed_buffers(port);
1060	spin_unlock_irq(&port->outvq_lock);
1061
1062	nonseekable_open(inode, filp);
1063
1064	/* Notify host of port being opened */
1065	send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
1066
1067	return 0;
1068out:
1069	kref_put(&port->kref, remove_port);
1070	return ret;
1071}
1072
1073static int port_fops_fasync(int fd, struct file *filp, int mode)
1074{
1075	struct port *port;
1076
1077	port = filp->private_data;
1078	return fasync_helper(fd, filp, mode, &port->async_queue);
1079}
1080
1081/*
1082 * The file operations that we support: programs in the guest can open
1083 * a console device, read from it, write to it, poll for data and
1084 * close it.  The devices are at
1085 *   /dev/vport<device number>p<port number>
1086 */
1087static const struct file_operations port_fops = {
1088	.owner = THIS_MODULE,
1089	.open  = port_fops_open,
1090	.read  = port_fops_read,
1091	.write = port_fops_write,
1092	.splice_write = port_fops_splice_write,
1093	.poll  = port_fops_poll,
1094	.release = port_fops_release,
1095	.fasync = port_fops_fasync,
1096	.llseek = no_llseek,
1097};
1098
1099/*
1100 * The put_chars() callback is pretty straightforward.
1101 *
1102 * We turn the characters into a scatter-gather list, add it to the
1103 * output queue and then kick the Host.  Then we sit here waiting for
1104 * it to finish: inefficient in theory, but in practice
1105 * implementations will do it immediately.
1106 */
1107static ssize_t put_chars(u32 vtermno, const u8 *buf, size_t count)
1108{
1109	struct port *port;
1110	struct scatterlist sg[1];
1111	void *data;
1112	int ret;
1113
 
 
 
1114	port = find_port_by_vtermno(vtermno);
1115	if (!port)
1116		return -EPIPE;
1117
1118	data = kmemdup(buf, count, GFP_ATOMIC);
1119	if (!data)
1120		return -ENOMEM;
1121
1122	sg_init_one(sg, data, count);
1123	ret = __send_to_port(port, sg, 1, count, data, false);
1124	kfree(data);
1125	return ret;
1126}
1127
1128/*
1129 * get_chars() is the callback from the hvc_console infrastructure
1130 * when an interrupt is received.
1131 *
1132 * We call out to fill_readbuf that gets us the required data from the
1133 * buffers that are queued up.
1134 */
1135static ssize_t get_chars(u32 vtermno, u8 *buf, size_t count)
1136{
1137	struct port *port;
1138
 
 
 
 
1139	port = find_port_by_vtermno(vtermno);
1140	if (!port)
1141		return -EPIPE;
1142
1143	/* If we don't have an input queue yet, we can't get input. */
1144	BUG_ON(!port->in_vq);
1145
1146	return fill_readbuf(port, (__force u8 __user *)buf, count, false);
1147}
1148
1149static void resize_console(struct port *port)
1150{
1151	struct virtio_device *vdev;
1152
1153	/* The port could have been hot-unplugged */
1154	if (!port || !is_console_port(port))
1155		return;
1156
1157	vdev = port->portdev->vdev;
1158
1159	/* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1160	if (!is_rproc_serial(vdev) &&
1161	    virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1162		hvc_resize(port->cons.hvc, port->cons.ws);
1163}
1164
1165/* We set the configuration at this point, since we now have a tty */
1166static int notifier_add_vio(struct hvc_struct *hp, int data)
1167{
1168	struct port *port;
1169
1170	port = find_port_by_vtermno(hp->vtermno);
1171	if (!port)
1172		return -EINVAL;
1173
1174	hp->irq_requested = 1;
1175	resize_console(port);
1176
1177	return 0;
1178}
1179
1180static void notifier_del_vio(struct hvc_struct *hp, int data)
1181{
1182	hp->irq_requested = 0;
1183}
1184
1185/* The operations for console ports. */
1186static const struct hv_ops hv_ops = {
1187	.get_chars = get_chars,
1188	.put_chars = put_chars,
1189	.notifier_add = notifier_add_vio,
1190	.notifier_del = notifier_del_vio,
1191	.notifier_hangup = notifier_del_vio,
1192};
1193
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1194static int init_port_console(struct port *port)
1195{
1196	int ret;
1197
1198	/*
1199	 * The Host's telling us this port is a console port.  Hook it
1200	 * up with an hvc console.
1201	 *
1202	 * To set up and manage our virtual console, we call
1203	 * hvc_alloc().
1204	 *
1205	 * The first argument of hvc_alloc() is the virtual console
1206	 * number.  The second argument is the parameter for the
1207	 * notification mechanism (like irq number).  We currently
1208	 * leave this as zero, virtqueues have implicit notifications.
1209	 *
1210	 * The third argument is a "struct hv_ops" containing the
1211	 * put_chars() get_chars(), notifier_add() and notifier_del()
1212	 * pointers.  The final argument is the output buffer size: we
1213	 * can do any size, so we put PAGE_SIZE here.
1214	 */
1215	ret = ida_alloc_min(&vtermno_ida, 1, GFP_KERNEL);
1216	if (ret < 0)
1217		return ret;
1218
1219	port->cons.vtermno = ret;
1220	port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1221	if (IS_ERR(port->cons.hvc)) {
1222		ret = PTR_ERR(port->cons.hvc);
1223		dev_err(port->dev,
1224			"error %d allocating hvc for port\n", ret);
1225		port->cons.hvc = NULL;
1226		ida_free(&vtermno_ida, port->cons.vtermno);
1227		return ret;
1228	}
1229	spin_lock_irq(&pdrvdata_lock);
 
1230	list_add_tail(&port->cons.list, &pdrvdata.consoles);
1231	spin_unlock_irq(&pdrvdata_lock);
1232	port->guest_connected = true;
1233
 
 
 
 
 
 
 
1234	/* Notify host of port being opened */
1235	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1236
1237	return 0;
1238}
1239
1240static ssize_t show_port_name(struct device *dev,
1241			      struct device_attribute *attr, char *buffer)
1242{
1243	struct port *port;
1244
1245	port = dev_get_drvdata(dev);
1246
1247	return sprintf(buffer, "%s\n", port->name);
1248}
1249
1250static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1251
1252static struct attribute *port_sysfs_entries[] = {
1253	&dev_attr_name.attr,
1254	NULL
1255};
1256
1257static const struct attribute_group port_attribute_group = {
1258	.name = NULL,		/* put in device directory */
1259	.attrs = port_sysfs_entries,
1260};
1261
1262static int port_debugfs_show(struct seq_file *s, void *data)
1263{
1264	struct port *port = s->private;
1265
1266	seq_printf(s, "name: %s\n", port->name ? port->name : "");
1267	seq_printf(s, "guest_connected: %d\n", port->guest_connected);
1268	seq_printf(s, "host_connected: %d\n", port->host_connected);
1269	seq_printf(s, "outvq_full: %d\n", port->outvq_full);
1270	seq_printf(s, "bytes_sent: %lu\n", port->stats.bytes_sent);
1271	seq_printf(s, "bytes_received: %lu\n", port->stats.bytes_received);
1272	seq_printf(s, "bytes_discarded: %lu\n", port->stats.bytes_discarded);
1273	seq_printf(s, "is_console: %s\n",
1274		   is_console_port(port) ? "yes" : "no");
1275	seq_printf(s, "console_vtermno: %u\n", port->cons.vtermno);
1276
1277	return 0;
1278}
1279
1280DEFINE_SHOW_ATTRIBUTE(port_debugfs);
1281
1282static void set_console_size(struct port *port, u16 rows, u16 cols)
1283{
1284	if (!port || !is_console_port(port))
1285		return;
1286
1287	port->cons.ws.ws_row = rows;
1288	port->cons.ws.ws_col = cols;
1289}
1290
1291static int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1292{
1293	struct port_buffer *buf;
1294	int nr_added_bufs;
1295	int ret;
1296
1297	nr_added_bufs = 0;
1298	do {
1299		buf = alloc_buf(vq->vdev, PAGE_SIZE, 0);
1300		if (!buf)
1301			return -ENOMEM;
1302
1303		spin_lock_irq(lock);
1304		ret = add_inbuf(vq, buf);
1305		if (ret < 0) {
1306			spin_unlock_irq(lock);
1307			free_buf(buf, true);
1308			return ret;
1309		}
1310		nr_added_bufs++;
1311		spin_unlock_irq(lock);
1312	} while (ret > 0);
1313
1314	return nr_added_bufs;
1315}
1316
1317static void send_sigio_to_port(struct port *port)
1318{
1319	if (port->async_queue && port->guest_connected)
1320		kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1321}
1322
1323static int add_port(struct ports_device *portdev, u32 id)
1324{
1325	char debugfs_name[16];
1326	struct port *port;
1327	dev_t devt;
1328	int err;
1329
1330	port = kmalloc(sizeof(*port), GFP_KERNEL);
1331	if (!port) {
1332		err = -ENOMEM;
1333		goto fail;
1334	}
1335	kref_init(&port->kref);
1336
1337	port->portdev = portdev;
1338	port->id = id;
1339
1340	port->name = NULL;
1341	port->inbuf = NULL;
1342	port->cons.hvc = NULL;
1343	port->async_queue = NULL;
1344
1345	port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1346	port->cons.vtermno = 0;
1347
1348	port->host_connected = port->guest_connected = false;
1349	port->stats = (struct port_stats) { 0 };
1350
1351	port->outvq_full = false;
1352
1353	port->in_vq = portdev->in_vqs[port->id];
1354	port->out_vq = portdev->out_vqs[port->id];
1355
1356	port->cdev = cdev_alloc();
1357	if (!port->cdev) {
1358		dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1359		err = -ENOMEM;
1360		goto free_port;
1361	}
1362	port->cdev->ops = &port_fops;
1363
1364	devt = MKDEV(portdev->chr_major, id);
1365	err = cdev_add(port->cdev, devt, 1);
1366	if (err < 0) {
1367		dev_err(&port->portdev->vdev->dev,
1368			"Error %d adding cdev for port %u\n", err, id);
1369		goto free_cdev;
1370	}
1371	port->dev = device_create(&port_class, &port->portdev->vdev->dev,
1372				  devt, port, "vport%up%u",
1373				  port->portdev->vdev->index, id);
1374	if (IS_ERR(port->dev)) {
1375		err = PTR_ERR(port->dev);
1376		dev_err(&port->portdev->vdev->dev,
1377			"Error %d creating device for port %u\n",
1378			err, id);
1379		goto free_cdev;
1380	}
1381
1382	spin_lock_init(&port->inbuf_lock);
1383	spin_lock_init(&port->outvq_lock);
1384	init_waitqueue_head(&port->waitqueue);
1385
1386	/* We can safely ignore ENOSPC because it means
1387	 * the queue already has buffers. Buffers are removed
1388	 * only by virtcons_remove(), not by unplug_port()
1389	 */
1390	err = fill_queue(port->in_vq, &port->inbuf_lock);
1391	if (err < 0 && err != -ENOSPC) {
1392		dev_err(port->dev, "Error allocating inbufs\n");
1393		goto free_device;
1394	}
1395
1396	if (is_rproc_serial(port->portdev->vdev))
1397		/*
1398		 * For rproc_serial assume remote processor is connected.
1399		 * rproc_serial does not want the console port, only
1400		 * the generic port implementation.
1401		 */
1402		port->host_connected = true;
1403	else if (!use_multiport(port->portdev)) {
1404		/*
1405		 * If we're not using multiport support,
1406		 * this has to be a console port.
1407		 */
1408		err = init_port_console(port);
1409		if (err)
1410			goto free_inbufs;
1411	}
1412
1413	spin_lock_irq(&portdev->ports_lock);
1414	list_add_tail(&port->list, &port->portdev->ports);
1415	spin_unlock_irq(&portdev->ports_lock);
1416
1417	/*
1418	 * Tell the Host we're set so that it can send us various
1419	 * configuration parameters for this port (eg, port name,
1420	 * caching, whether this is a console port, etc.)
1421	 */
1422	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1423
1424	/*
1425	 * Finally, create the debugfs file that we can use to
1426	 * inspect a port's state at any time
1427	 */
1428	snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
1429		 port->portdev->vdev->index, id);
1430	port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1431						 pdrvdata.debugfs_dir,
1432						 port, &port_debugfs_fops);
 
 
 
1433	return 0;
1434
1435free_inbufs:
1436free_device:
1437	device_destroy(&port_class, port->dev->devt);
1438free_cdev:
1439	cdev_del(port->cdev);
1440free_port:
1441	kfree(port);
1442fail:
1443	/* The host might want to notify management sw about port add failure */
1444	__send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1445	return err;
1446}
1447
1448/* No users remain, remove all port-specific data. */
1449static void remove_port(struct kref *kref)
1450{
1451	struct port *port;
1452
1453	port = container_of(kref, struct port, kref);
1454
1455	kfree(port);
1456}
1457
1458static void remove_port_data(struct port *port)
1459{
1460	spin_lock_irq(&port->inbuf_lock);
1461	/* Remove unused data this port might have received. */
1462	discard_port_data(port);
1463	spin_unlock_irq(&port->inbuf_lock);
1464
1465	spin_lock_irq(&port->outvq_lock);
1466	reclaim_consumed_buffers(port);
1467	spin_unlock_irq(&port->outvq_lock);
1468}
1469
1470/*
1471 * Port got unplugged.  Remove port from portdev's list and drop the
1472 * kref reference.  If no userspace has this port opened, it will
1473 * result in immediate removal the port.
1474 */
1475static void unplug_port(struct port *port)
1476{
1477	spin_lock_irq(&port->portdev->ports_lock);
1478	list_del(&port->list);
1479	spin_unlock_irq(&port->portdev->ports_lock);
1480
1481	spin_lock_irq(&port->inbuf_lock);
1482	if (port->guest_connected) {
1483		/* Let the app know the port is going down. */
1484		send_sigio_to_port(port);
1485
1486		/* Do this after sigio is actually sent */
1487		port->guest_connected = false;
1488		port->host_connected = false;
1489
1490		wake_up_interruptible(&port->waitqueue);
1491	}
1492	spin_unlock_irq(&port->inbuf_lock);
1493
1494	if (is_console_port(port)) {
1495		spin_lock_irq(&pdrvdata_lock);
1496		list_del(&port->cons.list);
1497		spin_unlock_irq(&pdrvdata_lock);
1498		hvc_remove(port->cons.hvc);
1499		ida_free(&vtermno_ida, port->cons.vtermno);
1500	}
1501
1502	remove_port_data(port);
1503
1504	/*
1505	 * We should just assume the device itself has gone off --
1506	 * else a close on an open port later will try to send out a
1507	 * control message.
1508	 */
1509	port->portdev = NULL;
1510
1511	sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1512	device_destroy(&port_class, port->dev->devt);
1513	cdev_del(port->cdev);
1514
1515	debugfs_remove(port->debugfs_file);
1516	kfree(port->name);
1517
1518	/*
1519	 * Locks around here are not necessary - a port can't be
1520	 * opened after we removed the port struct from ports_list
1521	 * above.
1522	 */
1523	kref_put(&port->kref, remove_port);
1524}
1525
1526/* Any private messages that the Host and Guest want to share */
1527static void handle_control_message(struct virtio_device *vdev,
1528				   struct ports_device *portdev,
1529				   struct port_buffer *buf)
1530{
1531	struct virtio_console_control *cpkt;
1532	struct port *port;
1533	size_t name_size;
1534	int err;
1535
1536	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1537
1538	port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
1539	if (!port &&
1540	    cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
1541		/* No valid header at start of buffer.  Drop it. */
1542		dev_dbg(&portdev->vdev->dev,
1543			"Invalid index %u in control packet\n", cpkt->id);
1544		return;
1545	}
1546
1547	switch (virtio16_to_cpu(vdev, cpkt->event)) {
1548	case VIRTIO_CONSOLE_PORT_ADD:
1549		if (port) {
1550			dev_dbg(&portdev->vdev->dev,
1551				"Port %u already added\n", port->id);
1552			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1553			break;
1554		}
1555		if (virtio32_to_cpu(vdev, cpkt->id) >=
1556		    portdev->max_nr_ports) {
1557			dev_warn(&portdev->vdev->dev,
1558				"Request for adding port with "
1559				"out-of-bound id %u, max. supported id: %u\n",
1560				cpkt->id, portdev->max_nr_ports - 1);
1561			break;
1562		}
1563		add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
1564		break;
1565	case VIRTIO_CONSOLE_PORT_REMOVE:
1566		unplug_port(port);
1567		break;
1568	case VIRTIO_CONSOLE_CONSOLE_PORT:
1569		if (!cpkt->value)
1570			break;
1571		if (is_console_port(port))
1572			break;
1573
1574		init_port_console(port);
1575		complete(&early_console_added);
1576		/*
1577		 * Could remove the port here in case init fails - but
1578		 * have to notify the host first.
1579		 */
1580		break;
1581	case VIRTIO_CONSOLE_RESIZE: {
1582		struct {
1583			__u16 rows;
1584			__u16 cols;
1585		} size;
1586
1587		if (!is_console_port(port))
1588			break;
1589
1590		memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1591		       sizeof(size));
1592		set_console_size(port, size.rows, size.cols);
1593
1594		port->cons.hvc->irq_requested = 1;
1595		resize_console(port);
1596		break;
1597	}
1598	case VIRTIO_CONSOLE_PORT_OPEN:
1599		port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
1600		wake_up_interruptible(&port->waitqueue);
1601		/*
1602		 * If the host port got closed and the host had any
1603		 * unconsumed buffers, we'll be able to reclaim them
1604		 * now.
1605		 */
1606		spin_lock_irq(&port->outvq_lock);
1607		reclaim_consumed_buffers(port);
1608		spin_unlock_irq(&port->outvq_lock);
1609
1610		/*
1611		 * If the guest is connected, it'll be interested in
1612		 * knowing the host connection state changed.
1613		 */
1614		spin_lock_irq(&port->inbuf_lock);
1615		send_sigio_to_port(port);
1616		spin_unlock_irq(&port->inbuf_lock);
1617		break;
1618	case VIRTIO_CONSOLE_PORT_NAME:
1619		/*
1620		 * If we woke up after hibernation, we can get this
1621		 * again.  Skip it in that case.
1622		 */
1623		if (port->name)
1624			break;
1625
1626		/*
1627		 * Skip the size of the header and the cpkt to get the size
1628		 * of the name that was sent
1629		 */
1630		name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1631
1632		port->name = kmalloc(name_size, GFP_KERNEL);
1633		if (!port->name) {
1634			dev_err(port->dev,
1635				"Not enough space to store port name\n");
1636			break;
1637		}
1638		strscpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1639			name_size);
 
1640
1641		/*
1642		 * Since we only have one sysfs attribute, 'name',
1643		 * create it only if we have a name for the port.
1644		 */
1645		err = sysfs_create_group(&port->dev->kobj,
1646					 &port_attribute_group);
1647		if (err) {
1648			dev_err(port->dev,
1649				"Error %d creating sysfs device attributes\n",
1650				err);
1651		} else {
1652			/*
1653			 * Generate a udev event so that appropriate
1654			 * symlinks can be created based on udev
1655			 * rules.
1656			 */
1657			kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1658		}
1659		break;
1660	}
1661}
1662
1663static void control_work_handler(struct work_struct *work)
1664{
1665	struct ports_device *portdev;
1666	struct virtqueue *vq;
1667	struct port_buffer *buf;
1668	unsigned int len;
1669
1670	portdev = container_of(work, struct ports_device, control_work);
1671	vq = portdev->c_ivq;
1672
1673	spin_lock(&portdev->c_ivq_lock);
1674	while ((buf = virtqueue_get_buf(vq, &len))) {
1675		spin_unlock(&portdev->c_ivq_lock);
1676
1677		buf->len = min_t(size_t, len, buf->size);
1678		buf->offset = 0;
1679
1680		handle_control_message(vq->vdev, portdev, buf);
1681
1682		spin_lock(&portdev->c_ivq_lock);
1683		if (add_inbuf(portdev->c_ivq, buf) < 0) {
1684			dev_warn(&portdev->vdev->dev,
1685				 "Error adding buffer to queue\n");
1686			free_buf(buf, false);
1687		}
1688	}
1689	spin_unlock(&portdev->c_ivq_lock);
1690}
1691
1692static void flush_bufs(struct virtqueue *vq, bool can_sleep)
1693{
1694	struct port_buffer *buf;
1695	unsigned int len;
1696
1697	while ((buf = virtqueue_get_buf(vq, &len)))
1698		free_buf(buf, can_sleep);
1699}
1700
1701static void out_intr(struct virtqueue *vq)
1702{
1703	struct port *port;
1704
1705	port = find_port_by_vq(vq->vdev->priv, vq);
1706	if (!port) {
1707		flush_bufs(vq, false);
1708		return;
1709	}
1710
1711	wake_up_interruptible(&port->waitqueue);
1712}
1713
1714static void in_intr(struct virtqueue *vq)
1715{
1716	struct port *port;
1717	unsigned long flags;
1718
1719	port = find_port_by_vq(vq->vdev->priv, vq);
1720	if (!port) {
1721		flush_bufs(vq, false);
1722		return;
1723	}
1724
1725	spin_lock_irqsave(&port->inbuf_lock, flags);
1726	port->inbuf = get_inbuf(port);
1727
1728	/*
1729	 * Normally the port should not accept data when the port is
1730	 * closed. For generic serial ports, the host won't (shouldn't)
1731	 * send data till the guest is connected. But this condition
1732	 * can be reached when a console port is not yet connected (no
1733	 * tty is spawned) and the other side sends out data over the
1734	 * vring, or when a remote devices start sending data before
1735	 * the ports are opened.
1736	 *
1737	 * A generic serial port will discard data if not connected,
1738	 * while console ports and rproc-serial ports accepts data at
1739	 * any time. rproc-serial is initiated with guest_connected to
1740	 * false because port_fops_open expects this. Console ports are
1741	 * hooked up with an HVC console and is initialized with
1742	 * guest_connected to true.
1743	 */
1744
1745	if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1746		discard_port_data(port);
1747
1748	/* Send a SIGIO indicating new data in case the process asked for it */
1749	send_sigio_to_port(port);
1750
1751	spin_unlock_irqrestore(&port->inbuf_lock, flags);
1752
1753	wake_up_interruptible(&port->waitqueue);
1754
1755	if (is_console_port(port) && hvc_poll(port->cons.hvc))
1756		hvc_kick();
1757}
1758
1759static void control_intr(struct virtqueue *vq)
1760{
1761	struct ports_device *portdev;
1762
1763	portdev = vq->vdev->priv;
1764	schedule_work(&portdev->control_work);
1765}
1766
1767static void config_intr(struct virtio_device *vdev)
1768{
1769	struct ports_device *portdev;
1770
1771	portdev = vdev->priv;
1772
1773	if (!use_multiport(portdev))
1774		schedule_work(&portdev->config_work);
1775}
1776
1777static void config_work_handler(struct work_struct *work)
1778{
1779	struct ports_device *portdev;
1780
1781	portdev = container_of(work, struct ports_device, config_work);
1782	if (!use_multiport(portdev)) {
1783		struct virtio_device *vdev;
1784		struct port *port;
1785		u16 rows, cols;
1786
1787		vdev = portdev->vdev;
1788		virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1789		virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1790
1791		port = find_port_by_id(portdev, 0);
1792		set_console_size(port, rows, cols);
1793
1794		/*
1795		 * We'll use this way of resizing only for legacy
1796		 * support.  For newer userspace
1797		 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1798		 * to indicate console size changes so that it can be
1799		 * done per-port.
1800		 */
1801		resize_console(port);
1802	}
1803}
1804
1805static int init_vqs(struct ports_device *portdev)
1806{
1807	vq_callback_t **io_callbacks;
1808	char **io_names;
1809	struct virtqueue **vqs;
1810	u32 i, j, nr_ports, nr_queues;
1811	int err;
1812
1813	nr_ports = portdev->max_nr_ports;
1814	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1815
1816	vqs = kmalloc_array(nr_queues, sizeof(struct virtqueue *), GFP_KERNEL);
1817	io_callbacks = kmalloc_array(nr_queues, sizeof(vq_callback_t *),
1818				     GFP_KERNEL);
1819	io_names = kmalloc_array(nr_queues, sizeof(char *), GFP_KERNEL);
1820	portdev->in_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1821					GFP_KERNEL);
1822	portdev->out_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1823					 GFP_KERNEL);
1824	if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1825	    !portdev->out_vqs) {
1826		err = -ENOMEM;
1827		goto free;
1828	}
1829
1830	/*
1831	 * For backward compat (newer host but older guest), the host
1832	 * spawns a console port first and also inits the vqs for port
1833	 * 0 before others.
1834	 */
1835	j = 0;
1836	io_callbacks[j] = in_intr;
1837	io_callbacks[j + 1] = out_intr;
1838	io_names[j] = "input";
1839	io_names[j + 1] = "output";
1840	j += 2;
1841
1842	if (use_multiport(portdev)) {
1843		io_callbacks[j] = control_intr;
1844		io_callbacks[j + 1] = NULL;
1845		io_names[j] = "control-i";
1846		io_names[j + 1] = "control-o";
1847
1848		for (i = 1; i < nr_ports; i++) {
1849			j += 2;
1850			io_callbacks[j] = in_intr;
1851			io_callbacks[j + 1] = out_intr;
1852			io_names[j] = "input";
1853			io_names[j + 1] = "output";
1854		}
1855	}
1856	/* Find the queues. */
1857	err = virtio_find_vqs(portdev->vdev, nr_queues, vqs,
1858			      io_callbacks,
1859			      (const char **)io_names, NULL);
1860	if (err)
1861		goto free;
1862
1863	j = 0;
1864	portdev->in_vqs[0] = vqs[0];
1865	portdev->out_vqs[0] = vqs[1];
1866	j += 2;
1867	if (use_multiport(portdev)) {
1868		portdev->c_ivq = vqs[j];
1869		portdev->c_ovq = vqs[j + 1];
1870
1871		for (i = 1; i < nr_ports; i++) {
1872			j += 2;
1873			portdev->in_vqs[i] = vqs[j];
1874			portdev->out_vqs[i] = vqs[j + 1];
1875		}
1876	}
1877	kfree(io_names);
1878	kfree(io_callbacks);
1879	kfree(vqs);
1880
1881	return 0;
1882
1883free:
1884	kfree(portdev->out_vqs);
1885	kfree(portdev->in_vqs);
1886	kfree(io_names);
1887	kfree(io_callbacks);
1888	kfree(vqs);
1889
1890	return err;
1891}
1892
1893static const struct file_operations portdev_fops = {
1894	.owner = THIS_MODULE,
1895};
1896
1897static void remove_vqs(struct ports_device *portdev)
1898{
1899	struct virtqueue *vq;
1900
1901	virtio_device_for_each_vq(portdev->vdev, vq) {
1902		struct port_buffer *buf;
1903
1904		flush_bufs(vq, true);
1905		while ((buf = virtqueue_detach_unused_buf(vq)))
1906			free_buf(buf, true);
1907		cond_resched();
1908	}
1909	portdev->vdev->config->del_vqs(portdev->vdev);
1910	kfree(portdev->in_vqs);
1911	kfree(portdev->out_vqs);
1912}
1913
1914static void virtcons_remove(struct virtio_device *vdev)
1915{
1916	struct ports_device *portdev;
1917	struct port *port, *port2;
1918
1919	portdev = vdev->priv;
1920
1921	spin_lock_irq(&pdrvdata_lock);
1922	list_del(&portdev->list);
1923	spin_unlock_irq(&pdrvdata_lock);
1924
1925	/* Device is going away, exit any polling for buffers */
1926	virtio_break_device(vdev);
1927	if (use_multiport(portdev))
1928		flush_work(&portdev->control_work);
1929	else
1930		flush_work(&portdev->config_work);
1931
1932	/* Disable interrupts for vqs */
1933	virtio_reset_device(vdev);
1934	/* Finish up work that's lined up */
1935	if (use_multiport(portdev))
1936		cancel_work_sync(&portdev->control_work);
1937	else
1938		cancel_work_sync(&portdev->config_work);
1939
1940	list_for_each_entry_safe(port, port2, &portdev->ports, list)
1941		unplug_port(port);
1942
1943	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1944
1945	/*
1946	 * When yanking out a device, we immediately lose the
1947	 * (device-side) queues.  So there's no point in keeping the
1948	 * guest side around till we drop our final reference.  This
1949	 * also means that any ports which are in an open state will
1950	 * have to just stop using the port, as the vqs are going
1951	 * away.
1952	 */
1953	remove_vqs(portdev);
1954	kfree(portdev);
1955}
1956
1957/*
1958 * Once we're further in boot, we get probed like any other virtio
1959 * device.
1960 *
1961 * If the host also supports multiple console ports, we check the
1962 * config space to see how many ports the host has spawned.  We
1963 * initialize each port found.
1964 */
1965static int virtcons_probe(struct virtio_device *vdev)
1966{
1967	struct ports_device *portdev;
1968	int err;
1969	bool multiport;
 
1970
1971	/* We only need a config space if features are offered */
1972	if (!vdev->config->get &&
1973	    (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
1974	     || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
1975		dev_err(&vdev->dev, "%s failure: config access disabled\n",
1976			__func__);
1977		return -EINVAL;
1978	}
1979
 
 
 
1980	portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1981	if (!portdev) {
1982		err = -ENOMEM;
1983		goto fail;
1984	}
1985
1986	/* Attach this portdev to this virtio_device, and vice-versa. */
1987	portdev->vdev = vdev;
1988	vdev->priv = portdev;
1989
1990	portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1991					     &portdev_fops);
1992	if (portdev->chr_major < 0) {
1993		dev_err(&vdev->dev,
1994			"Error %d registering chrdev for device %u\n",
1995			portdev->chr_major, vdev->index);
1996		err = portdev->chr_major;
1997		goto free;
1998	}
1999
2000	multiport = false;
2001	portdev->max_nr_ports = 1;
2002
2003	/* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
2004	if (!is_rproc_serial(vdev) &&
2005	    virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
2006				 struct virtio_console_config, max_nr_ports,
2007				 &portdev->max_nr_ports) == 0) {
2008		if (portdev->max_nr_ports == 0 ||
2009		    portdev->max_nr_ports > VIRTCONS_MAX_PORTS) {
2010			dev_err(&vdev->dev,
2011				"Invalidate max_nr_ports %d",
2012				portdev->max_nr_ports);
2013			err = -EINVAL;
2014			goto free;
2015		}
2016		multiport = true;
2017	}
2018
2019	err = init_vqs(portdev);
2020	if (err < 0) {
2021		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2022		goto free_chrdev;
2023	}
2024
2025	spin_lock_init(&portdev->ports_lock);
2026	INIT_LIST_HEAD(&portdev->ports);
2027	INIT_LIST_HEAD(&portdev->list);
2028
2029	virtio_device_ready(portdev->vdev);
2030
2031	INIT_WORK(&portdev->config_work, &config_work_handler);
2032	INIT_WORK(&portdev->control_work, &control_work_handler);
2033
2034	if (multiport) {
2035		spin_lock_init(&portdev->c_ivq_lock);
2036		spin_lock_init(&portdev->c_ovq_lock);
2037
2038		err = fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2039		if (err < 0) {
2040			dev_err(&vdev->dev,
2041				"Error allocating buffers for control queue\n");
2042			/*
2043			 * The host might want to notify mgmt sw about device
2044			 * add failure.
2045			 */
2046			__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2047					   VIRTIO_CONSOLE_DEVICE_READY, 0);
2048			/* Device was functional: we need full cleanup. */
2049			virtcons_remove(vdev);
2050			return err;
2051		}
2052	} else {
2053		/*
2054		 * For backward compatibility: Create a console port
2055		 * if we're running on older host.
2056		 */
2057		add_port(portdev, 0);
2058	}
2059
2060	spin_lock_irq(&pdrvdata_lock);
2061	list_add_tail(&portdev->list, &pdrvdata.portdevs);
2062	spin_unlock_irq(&pdrvdata_lock);
2063
2064	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2065			   VIRTIO_CONSOLE_DEVICE_READY, 1);
2066
 
 
 
 
 
 
 
 
 
 
 
 
2067	return 0;
2068
2069free_chrdev:
2070	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2071free:
2072	kfree(portdev);
2073fail:
2074	return err;
2075}
2076
2077static const struct virtio_device_id id_table[] = {
2078	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2079	{ 0 },
2080};
2081MODULE_DEVICE_TABLE(virtio, id_table);
2082
2083static const unsigned int features[] = {
2084	VIRTIO_CONSOLE_F_SIZE,
2085	VIRTIO_CONSOLE_F_MULTIPORT,
2086};
2087
2088static const struct virtio_device_id rproc_serial_id_table[] = {
2089#if IS_ENABLED(CONFIG_REMOTEPROC)
2090	{ VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2091#endif
2092	{ 0 },
2093};
2094MODULE_DEVICE_TABLE(virtio, rproc_serial_id_table);
2095
2096static const unsigned int rproc_serial_features[] = {
2097};
2098
2099#ifdef CONFIG_PM_SLEEP
2100static int virtcons_freeze(struct virtio_device *vdev)
2101{
2102	struct ports_device *portdev;
2103	struct port *port;
2104
2105	portdev = vdev->priv;
2106
2107	virtio_reset_device(vdev);
2108
2109	if (use_multiport(portdev))
2110		virtqueue_disable_cb(portdev->c_ivq);
2111	cancel_work_sync(&portdev->control_work);
2112	cancel_work_sync(&portdev->config_work);
2113	/*
2114	 * Once more: if control_work_handler() was running, it would
2115	 * enable the cb as the last step.
2116	 */
2117	if (use_multiport(portdev))
2118		virtqueue_disable_cb(portdev->c_ivq);
2119
2120	list_for_each_entry(port, &portdev->ports, list) {
2121		virtqueue_disable_cb(port->in_vq);
2122		virtqueue_disable_cb(port->out_vq);
2123		/*
2124		 * We'll ask the host later if the new invocation has
2125		 * the port opened or closed.
2126		 */
2127		port->host_connected = false;
2128		remove_port_data(port);
2129	}
2130	remove_vqs(portdev);
2131
2132	return 0;
2133}
2134
2135static int virtcons_restore(struct virtio_device *vdev)
2136{
2137	struct ports_device *portdev;
2138	struct port *port;
2139	int ret;
2140
2141	portdev = vdev->priv;
2142
2143	ret = init_vqs(portdev);
2144	if (ret)
2145		return ret;
2146
2147	virtio_device_ready(portdev->vdev);
2148
2149	if (use_multiport(portdev))
2150		fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2151
2152	list_for_each_entry(port, &portdev->ports, list) {
2153		port->in_vq = portdev->in_vqs[port->id];
2154		port->out_vq = portdev->out_vqs[port->id];
2155
2156		fill_queue(port->in_vq, &port->inbuf_lock);
2157
2158		/* Get port open/close status on the host */
2159		send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2160
2161		/*
2162		 * If a port was open at the time of suspending, we
2163		 * have to let the host know that it's still open.
2164		 */
2165		if (port->guest_connected)
2166			send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2167	}
2168	return 0;
2169}
2170#endif
2171
2172static struct virtio_driver virtio_console = {
2173	.feature_table = features,
2174	.feature_table_size = ARRAY_SIZE(features),
2175	.driver.name =	KBUILD_MODNAME,
2176	.driver.owner =	THIS_MODULE,
2177	.id_table =	id_table,
2178	.probe =	virtcons_probe,
2179	.remove =	virtcons_remove,
2180	.config_changed = config_intr,
2181#ifdef CONFIG_PM_SLEEP
2182	.freeze =	virtcons_freeze,
2183	.restore =	virtcons_restore,
2184#endif
2185};
2186
2187static struct virtio_driver virtio_rproc_serial = {
2188	.feature_table = rproc_serial_features,
2189	.feature_table_size = ARRAY_SIZE(rproc_serial_features),
2190	.driver.name =	"virtio_rproc_serial",
2191	.driver.owner =	THIS_MODULE,
2192	.id_table =	rproc_serial_id_table,
2193	.probe =	virtcons_probe,
2194	.remove =	virtcons_remove,
2195};
2196
2197static int __init virtio_console_init(void)
2198{
2199	int err;
2200
2201	err = class_register(&port_class);
2202	if (err)
 
 
2203		return err;
 
2204
2205	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
 
 
2206	INIT_LIST_HEAD(&pdrvdata.consoles);
2207	INIT_LIST_HEAD(&pdrvdata.portdevs);
2208
2209	err = register_virtio_driver(&virtio_console);
2210	if (err < 0) {
2211		pr_err("Error %d registering virtio driver\n", err);
2212		goto free;
2213	}
2214	err = register_virtio_driver(&virtio_rproc_serial);
2215	if (err < 0) {
2216		pr_err("Error %d registering virtio rproc serial driver\n",
2217		       err);
2218		goto unregister;
2219	}
2220	return 0;
2221unregister:
2222	unregister_virtio_driver(&virtio_console);
2223free:
2224	debugfs_remove_recursive(pdrvdata.debugfs_dir);
2225	class_unregister(&port_class);
2226	return err;
2227}
2228
2229static void __exit virtio_console_fini(void)
2230{
2231	reclaim_dma_bufs();
2232
2233	unregister_virtio_driver(&virtio_console);
2234	unregister_virtio_driver(&virtio_rproc_serial);
2235
2236	class_unregister(&port_class);
2237	debugfs_remove_recursive(pdrvdata.debugfs_dir);
2238}
2239module_init(virtio_console_init);
2240module_exit(virtio_console_fini);
2241
2242MODULE_DESCRIPTION("Virtio console driver");
2243MODULE_LICENSE("GPL");