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