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};
1097
1098/*
1099 * The put_chars() callback is pretty straightforward.
1100 *
1101 * We turn the characters into a scatter-gather list, add it to the
1102 * output queue and then kick the Host.  Then we sit here waiting for
1103 * it to finish: inefficient in theory, but in practice
1104 * implementations will do it immediately.
1105 */
1106static ssize_t put_chars(u32 vtermno, const u8 *buf, size_t count)
1107{
1108	struct port *port;
1109	struct scatterlist sg[1];
1110	void *data;
1111	int ret;
1112
 
 
 
1113	port = find_port_by_vtermno(vtermno);
1114	if (!port)
1115		return -EPIPE;
1116
1117	data = kmemdup(buf, count, GFP_ATOMIC);
1118	if (!data)
1119		return -ENOMEM;
1120
1121	sg_init_one(sg, data, count);
1122	ret = __send_to_port(port, sg, 1, count, data, false);
1123	kfree(data);
1124	return ret;
1125}
1126
1127/*
1128 * get_chars() is the callback from the hvc_console infrastructure
1129 * when an interrupt is received.
1130 *
1131 * We call out to fill_readbuf that gets us the required data from the
1132 * buffers that are queued up.
1133 */
1134static ssize_t get_chars(u32 vtermno, u8 *buf, size_t count)
1135{
1136	struct port *port;
1137
 
 
 
 
1138	port = find_port_by_vtermno(vtermno);
1139	if (!port)
1140		return -EPIPE;
1141
1142	/* If we don't have an input queue yet, we can't get input. */
1143	BUG_ON(!port->in_vq);
1144
1145	return fill_readbuf(port, (__force u8 __user *)buf, count, false);
1146}
1147
1148static void resize_console(struct port *port)
1149{
1150	struct virtio_device *vdev;
1151
1152	/* The port could have been hot-unplugged */
1153	if (!port || !is_console_port(port))
1154		return;
1155
1156	vdev = port->portdev->vdev;
1157
1158	/* Don't test F_SIZE at all if we're rproc: not a valid feature! */
1159	if (!is_rproc_serial(vdev) &&
1160	    virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
1161		hvc_resize(port->cons.hvc, port->cons.ws);
1162}
1163
1164/* We set the configuration at this point, since we now have a tty */
1165static int notifier_add_vio(struct hvc_struct *hp, int data)
1166{
1167	struct port *port;
1168
1169	port = find_port_by_vtermno(hp->vtermno);
1170	if (!port)
1171		return -EINVAL;
1172
1173	hp->irq_requested = 1;
1174	resize_console(port);
1175
1176	return 0;
1177}
1178
1179static void notifier_del_vio(struct hvc_struct *hp, int data)
1180{
1181	hp->irq_requested = 0;
1182}
1183
1184/* The operations for console ports. */
1185static const struct hv_ops hv_ops = {
1186	.get_chars = get_chars,
1187	.put_chars = put_chars,
1188	.notifier_add = notifier_add_vio,
1189	.notifier_del = notifier_del_vio,
1190	.notifier_hangup = notifier_del_vio,
1191};
1192
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1193static int init_port_console(struct port *port)
1194{
1195	int ret;
1196
1197	/*
1198	 * The Host's telling us this port is a console port.  Hook it
1199	 * up with an hvc console.
1200	 *
1201	 * To set up and manage our virtual console, we call
1202	 * hvc_alloc().
1203	 *
1204	 * The first argument of hvc_alloc() is the virtual console
1205	 * number.  The second argument is the parameter for the
1206	 * notification mechanism (like irq number).  We currently
1207	 * leave this as zero, virtqueues have implicit notifications.
1208	 *
1209	 * The third argument is a "struct hv_ops" containing the
1210	 * put_chars() get_chars(), notifier_add() and notifier_del()
1211	 * pointers.  The final argument is the output buffer size: we
1212	 * can do any size, so we put PAGE_SIZE here.
1213	 */
1214	ret = ida_alloc_min(&vtermno_ida, 1, GFP_KERNEL);
1215	if (ret < 0)
1216		return ret;
1217
1218	port->cons.vtermno = ret;
1219	port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
1220	if (IS_ERR(port->cons.hvc)) {
1221		ret = PTR_ERR(port->cons.hvc);
1222		dev_err(port->dev,
1223			"error %d allocating hvc for port\n", ret);
1224		port->cons.hvc = NULL;
1225		ida_free(&vtermno_ida, port->cons.vtermno);
1226		return ret;
1227	}
1228	spin_lock_irq(&pdrvdata_lock);
 
1229	list_add_tail(&port->cons.list, &pdrvdata.consoles);
1230	spin_unlock_irq(&pdrvdata_lock);
1231	port->guest_connected = true;
1232
 
 
 
 
 
 
 
1233	/* Notify host of port being opened */
1234	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1235
1236	return 0;
1237}
1238
1239static ssize_t show_port_name(struct device *dev,
1240			      struct device_attribute *attr, char *buffer)
1241{
1242	struct port *port;
1243
1244	port = dev_get_drvdata(dev);
1245
1246	return sprintf(buffer, "%s\n", port->name);
1247}
1248
1249static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1250
1251static struct attribute *port_sysfs_entries[] = {
1252	&dev_attr_name.attr,
1253	NULL
1254};
1255
1256static const struct attribute_group port_attribute_group = {
1257	.name = NULL,		/* put in device directory */
1258	.attrs = port_sysfs_entries,
1259};
1260
1261static int port_debugfs_show(struct seq_file *s, void *data)
 
1262{
1263	struct port *port = s->private;
 
 
 
 
 
 
 
1264
1265	seq_printf(s, "name: %s\n", port->name ? port->name : "");
1266	seq_printf(s, "guest_connected: %d\n", port->guest_connected);
1267	seq_printf(s, "host_connected: %d\n", port->host_connected);
1268	seq_printf(s, "outvq_full: %d\n", port->outvq_full);
1269	seq_printf(s, "bytes_sent: %lu\n", port->stats.bytes_sent);
1270	seq_printf(s, "bytes_received: %lu\n", port->stats.bytes_received);
1271	seq_printf(s, "bytes_discarded: %lu\n", port->stats.bytes_discarded);
1272	seq_printf(s, "is_console: %s\n",
1273		   is_console_port(port) ? "yes" : "no");
1274	seq_printf(s, "console_vtermno: %u\n", port->cons.vtermno);
 
 
 
 
 
 
 
 
 
 
 
 
 
1275
1276	return 0;
 
 
1277}
1278
1279DEFINE_SHOW_ATTRIBUTE(port_debugfs);
 
 
 
 
1280
1281static void set_console_size(struct port *port, u16 rows, u16 cols)
1282{
1283	if (!port || !is_console_port(port))
1284		return;
1285
1286	port->cons.ws.ws_row = rows;
1287	port->cons.ws.ws_col = cols;
1288}
1289
1290static int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1291{
1292	struct port_buffer *buf;
1293	int nr_added_bufs;
1294	int ret;
1295
1296	nr_added_bufs = 0;
1297	do {
1298		buf = alloc_buf(vq->vdev, PAGE_SIZE, 0);
1299		if (!buf)
1300			return -ENOMEM;
1301
1302		spin_lock_irq(lock);
1303		ret = add_inbuf(vq, buf);
1304		if (ret < 0) {
1305			spin_unlock_irq(lock);
1306			free_buf(buf, true);
1307			return ret;
1308		}
1309		nr_added_bufs++;
1310		spin_unlock_irq(lock);
1311	} while (ret > 0);
1312
1313	return nr_added_bufs;
1314}
1315
1316static void send_sigio_to_port(struct port *port)
1317{
1318	if (port->async_queue && port->guest_connected)
1319		kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1320}
1321
1322static int add_port(struct ports_device *portdev, u32 id)
1323{
1324	char debugfs_name[16];
1325	struct port *port;
1326	dev_t devt;
 
1327	int err;
1328
1329	port = kmalloc(sizeof(*port), GFP_KERNEL);
1330	if (!port) {
1331		err = -ENOMEM;
1332		goto fail;
1333	}
1334	kref_init(&port->kref);
1335
1336	port->portdev = portdev;
1337	port->id = id;
1338
1339	port->name = NULL;
1340	port->inbuf = NULL;
1341	port->cons.hvc = NULL;
1342	port->async_queue = NULL;
1343
1344	port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1345	port->cons.vtermno = 0;
1346
1347	port->host_connected = port->guest_connected = false;
1348	port->stats = (struct port_stats) { 0 };
1349
1350	port->outvq_full = false;
1351
1352	port->in_vq = portdev->in_vqs[port->id];
1353	port->out_vq = portdev->out_vqs[port->id];
1354
1355	port->cdev = cdev_alloc();
1356	if (!port->cdev) {
1357		dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1358		err = -ENOMEM;
1359		goto free_port;
1360	}
1361	port->cdev->ops = &port_fops;
1362
1363	devt = MKDEV(portdev->chr_major, id);
1364	err = cdev_add(port->cdev, devt, 1);
1365	if (err < 0) {
1366		dev_err(&port->portdev->vdev->dev,
1367			"Error %d adding cdev for port %u\n", err, id);
1368		goto free_cdev;
1369	}
1370	port->dev = device_create(&port_class, &port->portdev->vdev->dev,
1371				  devt, port, "vport%up%u",
1372				  port->portdev->vdev->index, id);
1373	if (IS_ERR(port->dev)) {
1374		err = PTR_ERR(port->dev);
1375		dev_err(&port->portdev->vdev->dev,
1376			"Error %d creating device for port %u\n",
1377			err, id);
1378		goto free_cdev;
1379	}
1380
1381	spin_lock_init(&port->inbuf_lock);
1382	spin_lock_init(&port->outvq_lock);
1383	init_waitqueue_head(&port->waitqueue);
1384
1385	/* We can safely ignore ENOSPC because it means
1386	 * the queue already has buffers. Buffers are removed
1387	 * only by virtcons_remove(), not by unplug_port()
1388	 */
1389	err = fill_queue(port->in_vq, &port->inbuf_lock);
1390	if (err < 0 && err != -ENOSPC) {
1391		dev_err(port->dev, "Error allocating inbufs\n");
 
1392		goto free_device;
1393	}
1394
1395	if (is_rproc_serial(port->portdev->vdev))
1396		/*
1397		 * For rproc_serial assume remote processor is connected.
1398		 * rproc_serial does not want the console port, only
1399		 * the generic port implementation.
1400		 */
1401		port->host_connected = true;
1402	else if (!use_multiport(port->portdev)) {
1403		/*
1404		 * If we're not using multiport support,
1405		 * this has to be a console port.
1406		 */
1407		err = init_port_console(port);
1408		if (err)
1409			goto free_inbufs;
1410	}
1411
1412	spin_lock_irq(&portdev->ports_lock);
1413	list_add_tail(&port->list, &port->portdev->ports);
1414	spin_unlock_irq(&portdev->ports_lock);
1415
1416	/*
1417	 * Tell the Host we're set so that it can send us various
1418	 * configuration parameters for this port (eg, port name,
1419	 * caching, whether this is a console port, etc.)
1420	 */
1421	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1422
1423	/*
1424	 * Finally, create the debugfs file that we can use to
1425	 * inspect a port's state at any time
1426	 */
1427	snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
1428		 port->portdev->vdev->index, id);
1429	port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1430						 pdrvdata.debugfs_dir,
1431						 port, &port_debugfs_fops);
 
 
 
1432	return 0;
1433
1434free_inbufs:
1435free_device:
1436	device_destroy(&port_class, port->dev->devt);
1437free_cdev:
1438	cdev_del(port->cdev);
1439free_port:
1440	kfree(port);
1441fail:
1442	/* The host might want to notify management sw about port add failure */
1443	__send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1444	return err;
1445}
1446
1447/* No users remain, remove all port-specific data. */
1448static void remove_port(struct kref *kref)
1449{
1450	struct port *port;
1451
1452	port = container_of(kref, struct port, kref);
1453
1454	kfree(port);
1455}
1456
1457static void remove_port_data(struct port *port)
1458{
1459	spin_lock_irq(&port->inbuf_lock);
1460	/* Remove unused data this port might have received. */
1461	discard_port_data(port);
1462	spin_unlock_irq(&port->inbuf_lock);
1463
1464	spin_lock_irq(&port->outvq_lock);
1465	reclaim_consumed_buffers(port);
1466	spin_unlock_irq(&port->outvq_lock);
1467}
1468
1469/*
1470 * Port got unplugged.  Remove port from portdev's list and drop the
1471 * kref reference.  If no userspace has this port opened, it will
1472 * result in immediate removal the port.
1473 */
1474static void unplug_port(struct port *port)
1475{
1476	spin_lock_irq(&port->portdev->ports_lock);
1477	list_del(&port->list);
1478	spin_unlock_irq(&port->portdev->ports_lock);
1479
1480	spin_lock_irq(&port->inbuf_lock);
1481	if (port->guest_connected) {
1482		/* Let the app know the port is going down. */
1483		send_sigio_to_port(port);
1484
1485		/* Do this after sigio is actually sent */
1486		port->guest_connected = false;
1487		port->host_connected = false;
1488
1489		wake_up_interruptible(&port->waitqueue);
1490	}
1491	spin_unlock_irq(&port->inbuf_lock);
1492
1493	if (is_console_port(port)) {
1494		spin_lock_irq(&pdrvdata_lock);
1495		list_del(&port->cons.list);
1496		spin_unlock_irq(&pdrvdata_lock);
1497		hvc_remove(port->cons.hvc);
1498		ida_free(&vtermno_ida, port->cons.vtermno);
1499	}
1500
1501	remove_port_data(port);
1502
1503	/*
1504	 * We should just assume the device itself has gone off --
1505	 * else a close on an open port later will try to send out a
1506	 * control message.
1507	 */
1508	port->portdev = NULL;
1509
1510	sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1511	device_destroy(&port_class, port->dev->devt);
1512	cdev_del(port->cdev);
1513
1514	debugfs_remove(port->debugfs_file);
1515	kfree(port->name);
1516
1517	/*
1518	 * Locks around here are not necessary - a port can't be
1519	 * opened after we removed the port struct from ports_list
1520	 * above.
1521	 */
1522	kref_put(&port->kref, remove_port);
1523}
1524
1525/* Any private messages that the Host and Guest want to share */
1526static void handle_control_message(struct virtio_device *vdev,
1527				   struct ports_device *portdev,
1528				   struct port_buffer *buf)
1529{
1530	struct virtio_console_control *cpkt;
1531	struct port *port;
1532	size_t name_size;
1533	int err;
1534
1535	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1536
1537	port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
1538	if (!port &&
1539	    cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
1540		/* No valid header at start of buffer.  Drop it. */
1541		dev_dbg(&portdev->vdev->dev,
1542			"Invalid index %u in control packet\n", cpkt->id);
1543		return;
1544	}
1545
1546	switch (virtio16_to_cpu(vdev, cpkt->event)) {
1547	case VIRTIO_CONSOLE_PORT_ADD:
1548		if (port) {
1549			dev_dbg(&portdev->vdev->dev,
1550				"Port %u already added\n", port->id);
1551			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1552			break;
1553		}
1554		if (virtio32_to_cpu(vdev, cpkt->id) >=
1555		    portdev->max_nr_ports) {
1556			dev_warn(&portdev->vdev->dev,
1557				"Request for adding port with "
1558				"out-of-bound id %u, max. supported id: %u\n",
1559				cpkt->id, portdev->max_nr_ports - 1);
1560			break;
1561		}
1562		add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
1563		break;
1564	case VIRTIO_CONSOLE_PORT_REMOVE:
1565		unplug_port(port);
1566		break;
1567	case VIRTIO_CONSOLE_CONSOLE_PORT:
1568		if (!cpkt->value)
1569			break;
1570		if (is_console_port(port))
1571			break;
1572
1573		init_port_console(port);
1574		complete(&early_console_added);
1575		/*
1576		 * Could remove the port here in case init fails - but
1577		 * have to notify the host first.
1578		 */
1579		break;
1580	case VIRTIO_CONSOLE_RESIZE: {
1581		struct {
1582			__u16 rows;
1583			__u16 cols;
1584		} size;
1585
1586		if (!is_console_port(port))
1587			break;
1588
1589		memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1590		       sizeof(size));
1591		set_console_size(port, size.rows, size.cols);
1592
1593		port->cons.hvc->irq_requested = 1;
1594		resize_console(port);
1595		break;
1596	}
1597	case VIRTIO_CONSOLE_PORT_OPEN:
1598		port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
1599		wake_up_interruptible(&port->waitqueue);
1600		/*
1601		 * If the host port got closed and the host had any
1602		 * unconsumed buffers, we'll be able to reclaim them
1603		 * now.
1604		 */
1605		spin_lock_irq(&port->outvq_lock);
1606		reclaim_consumed_buffers(port);
1607		spin_unlock_irq(&port->outvq_lock);
1608
1609		/*
1610		 * If the guest is connected, it'll be interested in
1611		 * knowing the host connection state changed.
1612		 */
1613		spin_lock_irq(&port->inbuf_lock);
1614		send_sigio_to_port(port);
1615		spin_unlock_irq(&port->inbuf_lock);
1616		break;
1617	case VIRTIO_CONSOLE_PORT_NAME:
1618		/*
1619		 * If we woke up after hibernation, we can get this
1620		 * again.  Skip it in that case.
1621		 */
1622		if (port->name)
1623			break;
1624
1625		/*
1626		 * Skip the size of the header and the cpkt to get the size
1627		 * of the name that was sent
1628		 */
1629		name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1630
1631		port->name = kmalloc(name_size, GFP_KERNEL);
1632		if (!port->name) {
1633			dev_err(port->dev,
1634				"Not enough space to store port name\n");
1635			break;
1636		}
1637		strscpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1638			name_size);
 
1639
1640		/*
1641		 * Since we only have one sysfs attribute, 'name',
1642		 * create it only if we have a name for the port.
1643		 */
1644		err = sysfs_create_group(&port->dev->kobj,
1645					 &port_attribute_group);
1646		if (err) {
1647			dev_err(port->dev,
1648				"Error %d creating sysfs device attributes\n",
1649				err);
1650		} else {
1651			/*
1652			 * Generate a udev event so that appropriate
1653			 * symlinks can be created based on udev
1654			 * rules.
1655			 */
1656			kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1657		}
1658		break;
1659	}
1660}
1661
1662static void control_work_handler(struct work_struct *work)
1663{
1664	struct ports_device *portdev;
1665	struct virtqueue *vq;
1666	struct port_buffer *buf;
1667	unsigned int len;
1668
1669	portdev = container_of(work, struct ports_device, control_work);
1670	vq = portdev->c_ivq;
1671
1672	spin_lock(&portdev->c_ivq_lock);
1673	while ((buf = virtqueue_get_buf(vq, &len))) {
1674		spin_unlock(&portdev->c_ivq_lock);
1675
1676		buf->len = min_t(size_t, len, buf->size);
1677		buf->offset = 0;
1678
1679		handle_control_message(vq->vdev, portdev, buf);
1680
1681		spin_lock(&portdev->c_ivq_lock);
1682		if (add_inbuf(portdev->c_ivq, buf) < 0) {
1683			dev_warn(&portdev->vdev->dev,
1684				 "Error adding buffer to queue\n");
1685			free_buf(buf, false);
1686		}
1687	}
1688	spin_unlock(&portdev->c_ivq_lock);
1689}
1690
1691static void flush_bufs(struct virtqueue *vq, bool can_sleep)
1692{
1693	struct port_buffer *buf;
1694	unsigned int len;
1695
1696	while ((buf = virtqueue_get_buf(vq, &len)))
1697		free_buf(buf, can_sleep);
1698}
1699
1700static void out_intr(struct virtqueue *vq)
1701{
1702	struct port *port;
1703
1704	port = find_port_by_vq(vq->vdev->priv, vq);
1705	if (!port) {
1706		flush_bufs(vq, false);
1707		return;
1708	}
1709
1710	wake_up_interruptible(&port->waitqueue);
1711}
1712
1713static void in_intr(struct virtqueue *vq)
1714{
1715	struct port *port;
1716	unsigned long flags;
1717
1718	port = find_port_by_vq(vq->vdev->priv, vq);
1719	if (!port) {
1720		flush_bufs(vq, false);
1721		return;
1722	}
1723
1724	spin_lock_irqsave(&port->inbuf_lock, flags);
1725	port->inbuf = get_inbuf(port);
1726
1727	/*
1728	 * Normally the port should not accept data when the port is
1729	 * closed. For generic serial ports, the host won't (shouldn't)
1730	 * send data till the guest is connected. But this condition
1731	 * can be reached when a console port is not yet connected (no
1732	 * tty is spawned) and the other side sends out data over the
1733	 * vring, or when a remote devices start sending data before
1734	 * the ports are opened.
1735	 *
1736	 * A generic serial port will discard data if not connected,
1737	 * while console ports and rproc-serial ports accepts data at
1738	 * any time. rproc-serial is initiated with guest_connected to
1739	 * false because port_fops_open expects this. Console ports are
1740	 * hooked up with an HVC console and is initialized with
1741	 * guest_connected to true.
1742	 */
1743
1744	if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
1745		discard_port_data(port);
1746
1747	/* Send a SIGIO indicating new data in case the process asked for it */
1748	send_sigio_to_port(port);
1749
1750	spin_unlock_irqrestore(&port->inbuf_lock, flags);
1751
1752	wake_up_interruptible(&port->waitqueue);
1753
1754	if (is_console_port(port) && hvc_poll(port->cons.hvc))
1755		hvc_kick();
1756}
1757
1758static void control_intr(struct virtqueue *vq)
1759{
1760	struct ports_device *portdev;
1761
1762	portdev = vq->vdev->priv;
1763	schedule_work(&portdev->control_work);
1764}
1765
1766static void config_intr(struct virtio_device *vdev)
1767{
1768	struct ports_device *portdev;
1769
1770	portdev = vdev->priv;
1771
1772	if (!use_multiport(portdev))
1773		schedule_work(&portdev->config_work);
1774}
1775
1776static void config_work_handler(struct work_struct *work)
1777{
1778	struct ports_device *portdev;
1779
1780	portdev = container_of(work, struct ports_device, config_work);
1781	if (!use_multiport(portdev)) {
1782		struct virtio_device *vdev;
1783		struct port *port;
1784		u16 rows, cols;
1785
1786		vdev = portdev->vdev;
1787		virtio_cread(vdev, struct virtio_console_config, cols, &cols);
1788		virtio_cread(vdev, struct virtio_console_config, rows, &rows);
1789
1790		port = find_port_by_id(portdev, 0);
1791		set_console_size(port, rows, cols);
1792
1793		/*
1794		 * We'll use this way of resizing only for legacy
1795		 * support.  For newer userspace
1796		 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1797		 * to indicate console size changes so that it can be
1798		 * done per-port.
1799		 */
1800		resize_console(port);
1801	}
1802}
1803
1804static int init_vqs(struct ports_device *portdev)
1805{
1806	struct virtqueue_info *vqs_info;
 
1807	struct virtqueue **vqs;
1808	u32 i, j, nr_ports, nr_queues;
1809	int err;
1810
1811	nr_ports = portdev->max_nr_ports;
1812	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1813
1814	vqs = kmalloc_array(nr_queues, sizeof(struct virtqueue *), GFP_KERNEL);
1815	vqs_info = kcalloc(nr_queues, sizeof(*vqs_info), GFP_KERNEL);
1816	portdev->in_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1817					GFP_KERNEL);
1818	portdev->out_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
1819					 GFP_KERNEL);
1820	if (!vqs || !vqs_info || !portdev->in_vqs || !portdev->out_vqs) {
 
 
1821		err = -ENOMEM;
1822		goto free;
1823	}
1824
1825	/*
1826	 * For backward compat (newer host but older guest), the host
1827	 * spawns a console port first and also inits the vqs for port
1828	 * 0 before others.
1829	 */
1830	j = 0;
1831	vqs_info[j].callback = in_intr;
1832	vqs_info[j + 1].callback = out_intr;
1833	vqs_info[j].name = "input";
1834	vqs_info[j + 1].name = "output";
1835	j += 2;
1836
1837	if (use_multiport(portdev)) {
1838		vqs_info[j].callback = control_intr;
1839		vqs_info[j].name = "control-i";
1840		vqs_info[j + 1].name = "control-o";
 
1841
1842		for (i = 1; i < nr_ports; i++) {
1843			j += 2;
1844			vqs_info[j].callback = in_intr;
1845			vqs_info[j + 1].callback = out_intr;
1846			vqs_info[j].name = "input";
1847			vqs_info[j + 1].name = "output";
1848		}
1849	}
1850	/* Find the queues. */
1851	err = virtio_find_vqs(portdev->vdev, nr_queues, vqs, vqs_info, NULL);
 
 
1852	if (err)
1853		goto free;
1854
1855	j = 0;
1856	portdev->in_vqs[0] = vqs[0];
1857	portdev->out_vqs[0] = vqs[1];
1858	j += 2;
1859	if (use_multiport(portdev)) {
1860		portdev->c_ivq = vqs[j];
1861		portdev->c_ovq = vqs[j + 1];
1862
1863		for (i = 1; i < nr_ports; i++) {
1864			j += 2;
1865			portdev->in_vqs[i] = vqs[j];
1866			portdev->out_vqs[i] = vqs[j + 1];
1867		}
1868	}
1869	kfree(vqs_info);
 
1870	kfree(vqs);
1871
1872	return 0;
1873
1874free:
1875	kfree(portdev->out_vqs);
1876	kfree(portdev->in_vqs);
1877	kfree(vqs_info);
 
1878	kfree(vqs);
1879
1880	return err;
1881}
1882
1883static const struct file_operations portdev_fops = {
1884	.owner = THIS_MODULE,
1885};
1886
1887static void remove_vqs(struct ports_device *portdev)
1888{
1889	struct virtqueue *vq;
1890
1891	virtio_device_for_each_vq(portdev->vdev, vq) {
1892		struct port_buffer *buf;
1893
1894		flush_bufs(vq, true);
1895		while ((buf = virtqueue_detach_unused_buf(vq)))
1896			free_buf(buf, true);
1897		cond_resched();
1898	}
1899	portdev->vdev->config->del_vqs(portdev->vdev);
1900	kfree(portdev->in_vqs);
1901	kfree(portdev->out_vqs);
1902}
1903
1904static void virtcons_remove(struct virtio_device *vdev)
1905{
1906	struct ports_device *portdev;
1907	struct port *port, *port2;
1908
1909	portdev = vdev->priv;
1910
1911	spin_lock_irq(&pdrvdata_lock);
1912	list_del(&portdev->list);
1913	spin_unlock_irq(&pdrvdata_lock);
1914
1915	/* Device is going away, exit any polling for buffers */
1916	virtio_break_device(vdev);
1917	if (use_multiport(portdev))
1918		flush_work(&portdev->control_work);
1919	else
1920		flush_work(&portdev->config_work);
1921
1922	/* Disable interrupts for vqs */
1923	virtio_reset_device(vdev);
1924	/* Finish up work that's lined up */
1925	if (use_multiport(portdev))
1926		cancel_work_sync(&portdev->control_work);
1927	else
1928		cancel_work_sync(&portdev->config_work);
1929
1930	list_for_each_entry_safe(port, port2, &portdev->ports, list)
1931		unplug_port(port);
1932
1933	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1934
1935	/*
1936	 * When yanking out a device, we immediately lose the
1937	 * (device-side) queues.  So there's no point in keeping the
1938	 * guest side around till we drop our final reference.  This
1939	 * also means that any ports which are in an open state will
1940	 * have to just stop using the port, as the vqs are going
1941	 * away.
1942	 */
1943	remove_vqs(portdev);
1944	kfree(portdev);
1945}
1946
1947/*
1948 * Once we're further in boot, we get probed like any other virtio
1949 * device.
1950 *
1951 * If the host also supports multiple console ports, we check the
1952 * config space to see how many ports the host has spawned.  We
1953 * initialize each port found.
1954 */
1955static int virtcons_probe(struct virtio_device *vdev)
1956{
1957	struct ports_device *portdev;
1958	int err;
1959	bool multiport;
 
1960
1961	/* We only need a config space if features are offered */
1962	if (!vdev->config->get &&
1963	    (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
1964	     || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
1965		dev_err(&vdev->dev, "%s failure: config access disabled\n",
1966			__func__);
1967		return -EINVAL;
1968	}
1969
 
 
 
1970	portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1971	if (!portdev) {
1972		err = -ENOMEM;
1973		goto fail;
1974	}
1975
1976	/* Attach this portdev to this virtio_device, and vice-versa. */
1977	portdev->vdev = vdev;
1978	vdev->priv = portdev;
1979
1980	portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1981					     &portdev_fops);
1982	if (portdev->chr_major < 0) {
1983		dev_err(&vdev->dev,
1984			"Error %d registering chrdev for device %u\n",
1985			portdev->chr_major, vdev->index);
1986		err = portdev->chr_major;
1987		goto free;
1988	}
1989
1990	multiport = false;
1991	portdev->max_nr_ports = 1;
1992
1993	/* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
1994	if (!is_rproc_serial(vdev) &&
1995	    virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
1996				 struct virtio_console_config, max_nr_ports,
1997				 &portdev->max_nr_ports) == 0) {
1998		if (portdev->max_nr_ports == 0 ||
1999		    portdev->max_nr_ports > VIRTCONS_MAX_PORTS) {
2000			dev_err(&vdev->dev,
2001				"Invalidate max_nr_ports %d",
2002				portdev->max_nr_ports);
2003			err = -EINVAL;
2004			goto free;
2005		}
2006		multiport = true;
2007	}
2008
 
 
 
 
 
 
2009	spin_lock_init(&portdev->ports_lock);
2010	INIT_LIST_HEAD(&portdev->ports);
2011	INIT_LIST_HEAD(&portdev->list);
2012
 
 
2013	INIT_WORK(&portdev->config_work, &config_work_handler);
2014	INIT_WORK(&portdev->control_work, &control_work_handler);
2015
2016	if (multiport) {
 
 
2017		spin_lock_init(&portdev->c_ivq_lock);
2018		spin_lock_init(&portdev->c_ovq_lock);
2019	}
2020
2021	err = init_vqs(portdev);
2022	if (err < 0) {
2023		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
2024		goto free_chrdev;
2025	}
2026
2027	virtio_device_ready(portdev->vdev);
2028
2029	if (multiport) {
2030		err = fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2031		if (err < 0) {
2032			dev_err(&vdev->dev,
2033				"Error allocating buffers for control queue\n");
2034			/*
2035			 * The host might want to notify mgmt sw about device
2036			 * add failure.
2037			 */
2038			__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2039					   VIRTIO_CONSOLE_DEVICE_READY, 0);
2040			/* Device was functional: we need full cleanup. */
2041			virtcons_remove(vdev);
2042			return err;
2043		}
2044	} else {
2045		/*
2046		 * For backward compatibility: Create a console port
2047		 * if we're running on older host.
2048		 */
2049		add_port(portdev, 0);
2050	}
2051
2052	spin_lock_irq(&pdrvdata_lock);
2053	list_add_tail(&portdev->list, &pdrvdata.portdevs);
2054	spin_unlock_irq(&pdrvdata_lock);
2055
2056	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
2057			   VIRTIO_CONSOLE_DEVICE_READY, 1);
2058
 
 
 
 
 
 
 
 
 
 
 
 
2059	return 0;
2060
2061free_chrdev:
2062	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
2063free:
2064	kfree(portdev);
2065fail:
2066	return err;
2067}
2068
2069static const struct virtio_device_id id_table[] = {
2070	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
2071	{ 0 },
2072};
2073MODULE_DEVICE_TABLE(virtio, id_table);
2074
2075static const unsigned int features[] = {
2076	VIRTIO_CONSOLE_F_SIZE,
2077	VIRTIO_CONSOLE_F_MULTIPORT,
2078};
2079
2080static const struct virtio_device_id rproc_serial_id_table[] = {
2081#if IS_ENABLED(CONFIG_REMOTEPROC)
2082	{ VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
2083#endif
2084	{ 0 },
2085};
2086MODULE_DEVICE_TABLE(virtio, rproc_serial_id_table);
2087
2088static const unsigned int rproc_serial_features[] = {
2089};
2090
2091#ifdef CONFIG_PM_SLEEP
2092static int virtcons_freeze(struct virtio_device *vdev)
2093{
2094	struct ports_device *portdev;
2095	struct port *port;
2096
2097	portdev = vdev->priv;
2098
2099	virtio_reset_device(vdev);
2100
2101	if (use_multiport(portdev))
2102		virtqueue_disable_cb(portdev->c_ivq);
2103	cancel_work_sync(&portdev->control_work);
2104	cancel_work_sync(&portdev->config_work);
2105	/*
2106	 * Once more: if control_work_handler() was running, it would
2107	 * enable the cb as the last step.
2108	 */
2109	if (use_multiport(portdev))
2110		virtqueue_disable_cb(portdev->c_ivq);
2111
2112	list_for_each_entry(port, &portdev->ports, list) {
2113		virtqueue_disable_cb(port->in_vq);
2114		virtqueue_disable_cb(port->out_vq);
2115		/*
2116		 * We'll ask the host later if the new invocation has
2117		 * the port opened or closed.
2118		 */
2119		port->host_connected = false;
2120		remove_port_data(port);
2121	}
2122	remove_vqs(portdev);
2123
2124	return 0;
2125}
2126
2127static int virtcons_restore(struct virtio_device *vdev)
2128{
2129	struct ports_device *portdev;
2130	struct port *port;
2131	int ret;
2132
2133	portdev = vdev->priv;
2134
2135	ret = init_vqs(portdev);
2136	if (ret)
2137		return ret;
2138
2139	virtio_device_ready(portdev->vdev);
2140
2141	if (use_multiport(portdev))
2142		fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
2143
2144	list_for_each_entry(port, &portdev->ports, list) {
2145		port->in_vq = portdev->in_vqs[port->id];
2146		port->out_vq = portdev->out_vqs[port->id];
2147
2148		fill_queue(port->in_vq, &port->inbuf_lock);
2149
2150		/* Get port open/close status on the host */
2151		send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
2152
2153		/*
2154		 * If a port was open at the time of suspending, we
2155		 * have to let the host know that it's still open.
2156		 */
2157		if (port->guest_connected)
2158			send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
2159	}
2160	return 0;
2161}
2162#endif
2163
2164static struct virtio_driver virtio_console = {
2165	.feature_table = features,
2166	.feature_table_size = ARRAY_SIZE(features),
2167	.driver.name =	KBUILD_MODNAME,
 
2168	.id_table =	id_table,
2169	.probe =	virtcons_probe,
2170	.remove =	virtcons_remove,
2171	.config_changed = config_intr,
2172#ifdef CONFIG_PM_SLEEP
2173	.freeze =	virtcons_freeze,
2174	.restore =	virtcons_restore,
2175#endif
2176};
2177
2178static struct virtio_driver virtio_rproc_serial = {
2179	.feature_table = rproc_serial_features,
2180	.feature_table_size = ARRAY_SIZE(rproc_serial_features),
2181	.driver.name =	"virtio_rproc_serial",
 
2182	.id_table =	rproc_serial_id_table,
2183	.probe =	virtcons_probe,
2184	.remove =	virtcons_remove,
2185};
2186
2187static int __init virtio_console_init(void)
2188{
2189	int err;
2190
2191	err = class_register(&port_class);
2192	if (err)
 
 
2193		return err;
 
2194
2195	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
 
 
2196	INIT_LIST_HEAD(&pdrvdata.consoles);
2197	INIT_LIST_HEAD(&pdrvdata.portdevs);
2198
2199	err = register_virtio_driver(&virtio_console);
2200	if (err < 0) {
2201		pr_err("Error %d registering virtio driver\n", err);
2202		goto free;
2203	}
2204	err = register_virtio_driver(&virtio_rproc_serial);
2205	if (err < 0) {
2206		pr_err("Error %d registering virtio rproc serial driver\n",
2207		       err);
2208		goto unregister;
2209	}
2210	return 0;
2211unregister:
2212	unregister_virtio_driver(&virtio_console);
2213free:
2214	debugfs_remove_recursive(pdrvdata.debugfs_dir);
2215	class_unregister(&port_class);
2216	return err;
2217}
2218
2219static void __exit virtio_console_fini(void)
2220{
2221	reclaim_dma_bufs();
2222
2223	unregister_virtio_driver(&virtio_console);
2224	unregister_virtio_driver(&virtio_rproc_serial);
2225
2226	class_unregister(&port_class);
2227	debugfs_remove_recursive(pdrvdata.debugfs_dir);
2228}
2229module_init(virtio_console_init);
2230module_exit(virtio_console_fini);
2231
 
2232MODULE_DESCRIPTION("Virtio console driver");
2233MODULE_LICENSE("GPL");