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/drivers/char/virtio_console.c

https://bitbucket.org/cresqo/cm7-p500-kernel
C | 1683 lines | 1090 code | 278 blank | 315 comment | 127 complexity | f246dda0cd3d73d86a409fe13a0425ed MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
   1/*
   2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
   3 * Copyright (C) 2009, 2010 Red Hat, Inc.
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 */
  19#include <linux/cdev.h>
  20#include <linux/debugfs.h>
  21#include <linux/device.h>
  22#include <linux/err.h>
  23#include <linux/fs.h>
  24#include <linux/init.h>
  25#include <linux/list.h>
  26#include <linux/poll.h>
  27#include <linux/sched.h>
  28#include <linux/slab.h>
  29#include <linux/spinlock.h>
  30#include <linux/virtio.h>
  31#include <linux/virtio_console.h>
  32#include <linux/wait.h>
  33#include <linux/workqueue.h>
  34#include "hvc_console.h"
  35
  36/*
  37 * This is a global struct for storing common data for all the devices
  38 * this driver handles.
  39 *
  40 * Mainly, it has a linked list for all the consoles in one place so
  41 * that callbacks from hvc for get_chars(), put_chars() work properly
  42 * across multiple devices and multiple ports per device.
  43 */
  44struct ports_driver_data {
  45	/* Used for registering chardevs */
  46	struct class *class;
  47
  48	/* Used for exporting per-port information to debugfs */
  49	struct dentry *debugfs_dir;
  50
  51	/* Number of devices this driver is handling */
  52	unsigned int index;
  53
  54	/*
  55	 * This is used to keep track of the number of hvc consoles
  56	 * spawned by this driver.  This number is given as the first
  57	 * argument to hvc_alloc().  To correctly map an initial
  58	 * console spawned via hvc_instantiate to the console being
  59	 * hooked up via hvc_alloc, we need to pass the same vtermno.
  60	 *
  61	 * We also just assume the first console being initialised was
  62	 * the first one that got used as the initial console.
  63	 */
  64	unsigned int next_vtermno;
  65
  66	/* All the console devices handled by this driver */
  67	struct list_head consoles;
  68};
  69static struct ports_driver_data pdrvdata;
  70
  71DEFINE_SPINLOCK(pdrvdata_lock);
  72
  73/* This struct holds information that's relevant only for console ports */
  74struct console {
  75	/* We'll place all consoles in a list in the pdrvdata struct */
  76	struct list_head list;
  77
  78	/* The hvc device associated with this console port */
  79	struct hvc_struct *hvc;
  80
  81	/* The size of the console */
  82	struct winsize ws;
  83
  84	/*
  85	 * This number identifies the number that we used to register
  86	 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
  87	 * number passed on by the hvc callbacks to us to
  88	 * differentiate between the other console ports handled by
  89	 * this driver
  90	 */
  91	u32 vtermno;
  92};
  93
  94struct port_buffer {
  95	char *buf;
  96
  97	/* size of the buffer in *buf above */
  98	size_t size;
  99
 100	/* used length of the buffer */
 101	size_t len;
 102	/* offset in the buf from which to consume data */
 103	size_t offset;
 104};
 105
 106/*
 107 * This is a per-device struct that stores data common to all the
 108 * ports for that device (vdev->priv).
 109 */
 110struct ports_device {
 111	/*
 112	 * Workqueue handlers where we process deferred work after
 113	 * notification
 114	 */
 115	struct work_struct control_work;
 116
 117	struct list_head ports;
 118
 119	/* To protect the list of ports */
 120	spinlock_t ports_lock;
 121
 122	/* To protect the vq operations for the control channel */
 123	spinlock_t cvq_lock;
 124
 125	/* The current config space is stored here */
 126	struct virtio_console_config config;
 127
 128	/* The virtio device we're associated with */
 129	struct virtio_device *vdev;
 130
 131	/*
 132	 * A couple of virtqueues for the control channel: one for
 133	 * guest->host transfers, one for host->guest transfers
 134	 */
 135	struct virtqueue *c_ivq, *c_ovq;
 136
 137	/* Array of per-port IO virtqueues */
 138	struct virtqueue **in_vqs, **out_vqs;
 139
 140	/* Used for numbering devices for sysfs and debugfs */
 141	unsigned int drv_index;
 142
 143	/* Major number for this device.  Ports will be created as minors. */
 144	int chr_major;
 145};
 146
 147/* This struct holds the per-port data */
 148struct port {
 149	/* Next port in the list, head is in the ports_device */
 150	struct list_head list;
 151
 152	/* Pointer to the parent virtio_console device */
 153	struct ports_device *portdev;
 154
 155	/* The current buffer from which data has to be fed to readers */
 156	struct port_buffer *inbuf;
 157
 158	/*
 159	 * To protect the operations on the in_vq associated with this
 160	 * port.  Has to be a spinlock because it can be called from
 161	 * interrupt context (get_char()).
 162	 */
 163	spinlock_t inbuf_lock;
 164
 165	/* Protect the operations on the out_vq. */
 166	spinlock_t outvq_lock;
 167
 168	/* The IO vqs for this port */
 169	struct virtqueue *in_vq, *out_vq;
 170
 171	/* File in the debugfs directory that exposes this port's information */
 172	struct dentry *debugfs_file;
 173
 174	/*
 175	 * The entries in this struct will be valid if this port is
 176	 * hooked up to an hvc console
 177	 */
 178	struct console cons;
 179
 180	/* Each port associates with a separate char device */
 181	struct cdev cdev;
 182	struct device *dev;
 183
 184	/* A waitqueue for poll() or blocking read operations */
 185	wait_queue_head_t waitqueue;
 186
 187	/* The 'name' of the port that we expose via sysfs properties */
 188	char *name;
 189
 190	/* The 'id' to identify the port with the Host */
 191	u32 id;
 192
 193	bool outvq_full;
 194
 195	/* Is the host device open */
 196	bool host_connected;
 197
 198	/* We should allow only one process to open a port */
 199	bool guest_connected;
 200};
 201
 202/* This is the very early arch-specified put chars function. */
 203static int (*early_put_chars)(u32, const char *, int);
 204
 205static struct port *find_port_by_vtermno(u32 vtermno)
 206{
 207	struct port *port;
 208	struct console *cons;
 209	unsigned long flags;
 210
 211	spin_lock_irqsave(&pdrvdata_lock, flags);
 212	list_for_each_entry(cons, &pdrvdata.consoles, list) {
 213		if (cons->vtermno == vtermno) {
 214			port = container_of(cons, struct port, cons);
 215			goto out;
 216		}
 217	}
 218	port = NULL;
 219out:
 220	spin_unlock_irqrestore(&pdrvdata_lock, flags);
 221	return port;
 222}
 223
 224static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 225{
 226	struct port *port;
 227	unsigned long flags;
 228
 229	spin_lock_irqsave(&portdev->ports_lock, flags);
 230	list_for_each_entry(port, &portdev->ports, list)
 231		if (port->id == id)
 232			goto out;
 233	port = NULL;
 234out:
 235	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 236
 237	return port;
 238}
 239
 240static struct port *find_port_by_vq(struct ports_device *portdev,
 241				    struct virtqueue *vq)
 242{
 243	struct port *port;
 244	unsigned long flags;
 245
 246	spin_lock_irqsave(&portdev->ports_lock, flags);
 247	list_for_each_entry(port, &portdev->ports, list)
 248		if (port->in_vq == vq || port->out_vq == vq)
 249			goto out;
 250	port = NULL;
 251out:
 252	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 253	return port;
 254}
 255
 256static bool is_console_port(struct port *port)
 257{
 258	if (port->cons.hvc)
 259		return true;
 260	return false;
 261}
 262
 263static inline bool use_multiport(struct ports_device *portdev)
 264{
 265	/*
 266	 * This condition can be true when put_chars is called from
 267	 * early_init
 268	 */
 269	if (!portdev->vdev)
 270		return 0;
 271	return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 272}
 273
 274static void free_buf(struct port_buffer *buf)
 275{
 276	kfree(buf->buf);
 277	kfree(buf);
 278}
 279
 280static struct port_buffer *alloc_buf(size_t buf_size)
 281{
 282	struct port_buffer *buf;
 283
 284	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
 285	if (!buf)
 286		goto fail;
 287	buf->buf = kzalloc(buf_size, GFP_KERNEL);
 288	if (!buf->buf)
 289		goto free_buf;
 290	buf->len = 0;
 291	buf->offset = 0;
 292	buf->size = buf_size;
 293	return buf;
 294
 295free_buf:
 296	kfree(buf);
 297fail:
 298	return NULL;
 299}
 300
 301/* Callers should take appropriate locks */
 302static void *get_inbuf(struct port *port)
 303{
 304	struct port_buffer *buf;
 305	struct virtqueue *vq;
 306	unsigned int len;
 307
 308	vq = port->in_vq;
 309	buf = virtqueue_get_buf(vq, &len);
 310	if (buf) {
 311		buf->len = len;
 312		buf->offset = 0;
 313	}
 314	return buf;
 315}
 316
 317/*
 318 * Create a scatter-gather list representing our input buffer and put
 319 * it in the queue.
 320 *
 321 * Callers should take appropriate locks.
 322 */
 323static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 324{
 325	struct scatterlist sg[1];
 326	int ret;
 327
 328	sg_init_one(sg, buf->buf, buf->size);
 329
 330	ret = virtqueue_add_buf(vq, sg, 0, 1, buf);
 331	virtqueue_kick(vq);
 332	return ret;
 333}
 334
 335/* Discard any unread data this port has. Callers lockers. */
 336static void discard_port_data(struct port *port)
 337{
 338	struct port_buffer *buf;
 339	struct virtqueue *vq;
 340	unsigned int len;
 341	int ret;
 342
 343	vq = port->in_vq;
 344	if (port->inbuf)
 345		buf = port->inbuf;
 346	else
 347		buf = virtqueue_get_buf(vq, &len);
 348
 349	ret = 0;
 350	while (buf) {
 351		if (add_inbuf(vq, buf) < 0) {
 352			ret++;
 353			free_buf(buf);
 354		}
 355		buf = virtqueue_get_buf(vq, &len);
 356	}
 357	port->inbuf = NULL;
 358	if (ret)
 359		dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
 360			 ret);
 361}
 362
 363static bool port_has_data(struct port *port)
 364{
 365	unsigned long flags;
 366	bool ret;
 367
 368	spin_lock_irqsave(&port->inbuf_lock, flags);
 369	if (port->inbuf) {
 370		ret = true;
 371		goto out;
 372	}
 373	port->inbuf = get_inbuf(port);
 374	if (port->inbuf) {
 375		ret = true;
 376		goto out;
 377	}
 378	ret = false;
 379out:
 380	spin_unlock_irqrestore(&port->inbuf_lock, flags);
 381	return ret;
 382}
 383
 384static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
 385				  unsigned int event, unsigned int value)
 386{
 387	struct scatterlist sg[1];
 388	struct virtio_console_control cpkt;
 389	struct virtqueue *vq;
 390	unsigned int len;
 391
 392	if (!use_multiport(portdev))
 393		return 0;
 394
 395	cpkt.id = port_id;
 396	cpkt.event = event;
 397	cpkt.value = value;
 398
 399	vq = portdev->c_ovq;
 400
 401	sg_init_one(sg, &cpkt, sizeof(cpkt));
 402	if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
 403		virtqueue_kick(vq);
 404		while (!virtqueue_get_buf(vq, &len))
 405			cpu_relax();
 406	}
 407	return 0;
 408}
 409
 410static ssize_t send_control_msg(struct port *port, unsigned int event,
 411				unsigned int value)
 412{
 413	return __send_control_msg(port->portdev, port->id, event, value);
 414}
 415
 416/* Callers must take the port->outvq_lock */
 417static void reclaim_consumed_buffers(struct port *port)
 418{
 419	void *buf;
 420	unsigned int len;
 421
 422	while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
 423		kfree(buf);
 424		port->outvq_full = false;
 425	}
 426}
 427
 428static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
 429			bool nonblock)
 430{
 431	struct scatterlist sg[1];
 432	struct virtqueue *out_vq;
 433	ssize_t ret;
 434	unsigned long flags;
 435	unsigned int len;
 436
 437	out_vq = port->out_vq;
 438
 439	spin_lock_irqsave(&port->outvq_lock, flags);
 440
 441	reclaim_consumed_buffers(port);
 442
 443	sg_init_one(sg, in_buf, in_count);
 444	ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf);
 445
 446	/* Tell Host to go! */
 447	virtqueue_kick(out_vq);
 448
 449	if (ret < 0) {
 450		in_count = 0;
 451		goto done;
 452	}
 453
 454	if (ret == 0)
 455		port->outvq_full = true;
 456
 457	if (nonblock)
 458		goto done;
 459
 460	/*
 461	 * Wait till the host acknowledges it pushed out the data we
 462	 * sent.  This is done for data from the hvc_console; the tty
 463	 * operations are performed with spinlocks held so we can't
 464	 * sleep here.  An alternative would be to copy the data to a
 465	 * buffer and relax the spinning requirement.  The downside is
 466	 * we need to kmalloc a GFP_ATOMIC buffer each time the
 467	 * console driver writes something out.
 468	 */
 469	while (!virtqueue_get_buf(out_vq, &len))
 470		cpu_relax();
 471done:
 472	spin_unlock_irqrestore(&port->outvq_lock, flags);
 473	/*
 474	 * We're expected to return the amount of data we wrote -- all
 475	 * of it
 476	 */
 477	return in_count;
 478}
 479
 480/*
 481 * Give out the data that's requested from the buffer that we have
 482 * queued up.
 483 */
 484static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
 485			    bool to_user)
 486{
 487	struct port_buffer *buf;
 488	unsigned long flags;
 489
 490	if (!out_count || !port_has_data(port))
 491		return 0;
 492
 493	buf = port->inbuf;
 494	out_count = min(out_count, buf->len - buf->offset);
 495
 496	if (to_user) {
 497		ssize_t ret;
 498
 499		ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
 500		if (ret)
 501			return -EFAULT;
 502	} else {
 503		memcpy(out_buf, buf->buf + buf->offset, out_count);
 504	}
 505
 506	buf->offset += out_count;
 507
 508	if (buf->offset == buf->len) {
 509		/*
 510		 * We're done using all the data in this buffer.
 511		 * Re-queue so that the Host can send us more data.
 512		 */
 513		spin_lock_irqsave(&port->inbuf_lock, flags);
 514		port->inbuf = NULL;
 515
 516		if (add_inbuf(port->in_vq, buf) < 0)
 517			dev_warn(port->dev, "failed add_buf\n");
 518
 519		spin_unlock_irqrestore(&port->inbuf_lock, flags);
 520	}
 521	/* Return the number of bytes actually copied */
 522	return out_count;
 523}
 524
 525/* The condition that must be true for polling to end */
 526static bool will_read_block(struct port *port)
 527{
 528	return !port_has_data(port) && port->host_connected;
 529}
 530
 531static bool will_write_block(struct port *port)
 532{
 533	bool ret;
 534
 535	if (!port->guest_connected) {
 536		/* Port got hot-unplugged. Let's exit. */
 537		return false;
 538	}
 539	if (!port->host_connected)
 540		return true;
 541
 542	spin_lock_irq(&port->outvq_lock);
 543	/*
 544	 * Check if the Host has consumed any buffers since we last
 545	 * sent data (this is only applicable for nonblocking ports).
 546	 */
 547	reclaim_consumed_buffers(port);
 548	ret = port->outvq_full;
 549	spin_unlock_irq(&port->outvq_lock);
 550
 551	return ret;
 552}
 553
 554static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
 555			      size_t count, loff_t *offp)
 556{
 557	struct port *port;
 558	ssize_t ret;
 559
 560	port = filp->private_data;
 561
 562	if (!port_has_data(port)) {
 563		/*
 564		 * If nothing's connected on the host just return 0 in
 565		 * case of list_empty; this tells the userspace app
 566		 * that there's no connection
 567		 */
 568		if (!port->host_connected)
 569			return 0;
 570		if (filp->f_flags & O_NONBLOCK)
 571			return -EAGAIN;
 572
 573		ret = wait_event_interruptible(port->waitqueue,
 574					       !will_read_block(port));
 575		if (ret < 0)
 576			return ret;
 577	}
 578	/*
 579	 * We could've received a disconnection message while we were
 580	 * waiting for more data.
 581	 *
 582	 * This check is not clubbed in the if() statement above as we
 583	 * might receive some data as well as the host could get
 584	 * disconnected after we got woken up from our wait.  So we
 585	 * really want to give off whatever data we have and only then
 586	 * check for host_connected.
 587	 */
 588	if (!port_has_data(port) && !port->host_connected)
 589		return 0;
 590
 591	return fill_readbuf(port, ubuf, count, true);
 592}
 593
 594static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 595			       size_t count, loff_t *offp)
 596{
 597	struct port *port;
 598	char *buf;
 599	ssize_t ret;
 600	bool nonblock;
 601
 602	/* Userspace could be out to fool us */
 603	if (!count)
 604		return 0;
 605
 606	port = filp->private_data;
 607
 608	nonblock = filp->f_flags & O_NONBLOCK;
 609
 610	if (will_write_block(port)) {
 611		if (nonblock)
 612			return -EAGAIN;
 613
 614		ret = wait_event_interruptible(port->waitqueue,
 615					       !will_write_block(port));
 616		if (ret < 0)
 617			return ret;
 618	}
 619
 620	count = min((size_t)(32 * 1024), count);
 621
 622	buf = kmalloc(count, GFP_KERNEL);
 623	if (!buf)
 624		return -ENOMEM;
 625
 626	ret = copy_from_user(buf, ubuf, count);
 627	if (ret) {
 628		ret = -EFAULT;
 629		goto free_buf;
 630	}
 631
 632	/*
 633	 * We now ask send_buf() to not spin for generic ports -- we
 634	 * can re-use the same code path that non-blocking file
 635	 * descriptors take for blocking file descriptors since the
 636	 * wait is already done and we're certain the write will go
 637	 * through to the host.
 638	 */
 639	nonblock = true;
 640	ret = send_buf(port, buf, count, nonblock);
 641
 642	if (nonblock && ret > 0)
 643		goto out;
 644
 645free_buf:
 646	kfree(buf);
 647out:
 648	return ret;
 649}
 650
 651static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
 652{
 653	struct port *port;
 654	unsigned int ret;
 655
 656	port = filp->private_data;
 657	poll_wait(filp, &port->waitqueue, wait);
 658
 659	ret = 0;
 660	if (!will_read_block(port))
 661		ret |= POLLIN | POLLRDNORM;
 662	if (!will_write_block(port))
 663		ret |= POLLOUT;
 664	if (!port->host_connected)
 665		ret |= POLLHUP;
 666
 667	return ret;
 668}
 669
 670static int port_fops_release(struct inode *inode, struct file *filp)
 671{
 672	struct port *port;
 673
 674	port = filp->private_data;
 675
 676	/* Notify host of port being closed */
 677	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 678
 679	spin_lock_irq(&port->inbuf_lock);
 680	port->guest_connected = false;
 681
 682	discard_port_data(port);
 683
 684	spin_unlock_irq(&port->inbuf_lock);
 685
 686	spin_lock_irq(&port->outvq_lock);
 687	reclaim_consumed_buffers(port);
 688	spin_unlock_irq(&port->outvq_lock);
 689
 690	return 0;
 691}
 692
 693static int port_fops_open(struct inode *inode, struct file *filp)
 694{
 695	struct cdev *cdev = inode->i_cdev;
 696	struct port *port;
 697
 698	port = container_of(cdev, struct port, cdev);
 699	filp->private_data = port;
 700
 701	/*
 702	 * Don't allow opening of console port devices -- that's done
 703	 * via /dev/hvc
 704	 */
 705	if (is_console_port(port))
 706		return -ENXIO;
 707
 708	/* Allow only one process to open a particular port at a time */
 709	spin_lock_irq(&port->inbuf_lock);
 710	if (port->guest_connected) {
 711		spin_unlock_irq(&port->inbuf_lock);
 712		return -EMFILE;
 713	}
 714
 715	port->guest_connected = true;
 716	spin_unlock_irq(&port->inbuf_lock);
 717
 718	spin_lock_irq(&port->outvq_lock);
 719	/*
 720	 * There might be a chance that we missed reclaiming a few
 721	 * buffers in the window of the port getting previously closed
 722	 * and opening now.
 723	 */
 724	reclaim_consumed_buffers(port);
 725	spin_unlock_irq(&port->outvq_lock);
 726
 727	/* Notify host of port being opened */
 728	send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
 729
 730	return 0;
 731}
 732
 733/*
 734 * The file operations that we support: programs in the guest can open
 735 * a console device, read from it, write to it, poll for data and
 736 * close it.  The devices are at
 737 *   /dev/vport<device number>p<port number>
 738 */
 739static const struct file_operations port_fops = {
 740	.owner = THIS_MODULE,
 741	.open  = port_fops_open,
 742	.read  = port_fops_read,
 743	.write = port_fops_write,
 744	.poll  = port_fops_poll,
 745	.release = port_fops_release,
 746};
 747
 748/*
 749 * The put_chars() callback is pretty straightforward.
 750 *
 751 * We turn the characters into a scatter-gather list, add it to the
 752 * output queue and then kick the Host.  Then we sit here waiting for
 753 * it to finish: inefficient in theory, but in practice
 754 * implementations will do it immediately (lguest's Launcher does).
 755 */
 756static int put_chars(u32 vtermno, const char *buf, int count)
 757{
 758	struct port *port;
 759
 760	if (unlikely(early_put_chars))
 761		return early_put_chars(vtermno, buf, count);
 762
 763	port = find_port_by_vtermno(vtermno);
 764	if (!port)
 765		return -EPIPE;
 766
 767	return send_buf(port, (void *)buf, count, false);
 768}
 769
 770/*
 771 * get_chars() is the callback from the hvc_console infrastructure
 772 * when an interrupt is received.
 773 *
 774 * We call out to fill_readbuf that gets us the required data from the
 775 * buffers that are queued up.
 776 */
 777static int get_chars(u32 vtermno, char *buf, int count)
 778{
 779	struct port *port;
 780
 781	/* If we've not set up the port yet, we have no input to give. */
 782	if (unlikely(early_put_chars))
 783		return 0;
 784
 785	port = find_port_by_vtermno(vtermno);
 786	if (!port)
 787		return -EPIPE;
 788
 789	/* If we don't have an input queue yet, we can't get input. */
 790	BUG_ON(!port->in_vq);
 791
 792	return fill_readbuf(port, buf, count, false);
 793}
 794
 795static void resize_console(struct port *port)
 796{
 797	struct virtio_device *vdev;
 798
 799	/* The port could have been hot-unplugged */
 800	if (!port || !is_console_port(port))
 801		return;
 802
 803	vdev = port->portdev->vdev;
 804	if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
 805		hvc_resize(port->cons.hvc, port->cons.ws);
 806}
 807
 808/* We set the configuration at this point, since we now have a tty */
 809static int notifier_add_vio(struct hvc_struct *hp, int data)
 810{
 811	struct port *port;
 812
 813	port = find_port_by_vtermno(hp->vtermno);
 814	if (!port)
 815		return -EINVAL;
 816
 817	hp->irq_requested = 1;
 818	resize_console(port);
 819
 820	return 0;
 821}
 822
 823static void notifier_del_vio(struct hvc_struct *hp, int data)
 824{
 825	hp->irq_requested = 0;
 826}
 827
 828/* The operations for console ports. */
 829static const struct hv_ops hv_ops = {
 830	.get_chars = get_chars,
 831	.put_chars = put_chars,
 832	.notifier_add = notifier_add_vio,
 833	.notifier_del = notifier_del_vio,
 834	.notifier_hangup = notifier_del_vio,
 835};
 836
 837/*
 838 * Console drivers are initialized very early so boot messages can go
 839 * out, so we do things slightly differently from the generic virtio
 840 * initialization of the net and block drivers.
 841 *
 842 * At this stage, the console is output-only.  It's too early to set
 843 * up a virtqueue, so we let the drivers do some boutique early-output
 844 * thing.
 845 */
 846int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
 847{
 848	early_put_chars = put_chars;
 849	return hvc_instantiate(0, 0, &hv_ops);
 850}
 851
 852int init_port_console(struct port *port)
 853{
 854	int ret;
 855
 856	/*
 857	 * The Host's telling us this port is a console port.  Hook it
 858	 * up with an hvc console.
 859	 *
 860	 * To set up and manage our virtual console, we call
 861	 * hvc_alloc().
 862	 *
 863	 * The first argument of hvc_alloc() is the virtual console
 864	 * number.  The second argument is the parameter for the
 865	 * notification mechanism (like irq number).  We currently
 866	 * leave this as zero, virtqueues have implicit notifications.
 867	 *
 868	 * The third argument is a "struct hv_ops" containing the
 869	 * put_chars() get_chars(), notifier_add() and notifier_del()
 870	 * pointers.  The final argument is the output buffer size: we
 871	 * can do any size, so we put PAGE_SIZE here.
 872	 */
 873	port->cons.vtermno = pdrvdata.next_vtermno;
 874
 875	port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
 876	if (IS_ERR(port->cons.hvc)) {
 877		ret = PTR_ERR(port->cons.hvc);
 878		dev_err(port->dev,
 879			"error %d allocating hvc for port\n", ret);
 880		port->cons.hvc = NULL;
 881		return ret;
 882	}
 883	spin_lock_irq(&pdrvdata_lock);
 884	pdrvdata.next_vtermno++;
 885	list_add_tail(&port->cons.list, &pdrvdata.consoles);
 886	spin_unlock_irq(&pdrvdata_lock);
 887	port->guest_connected = true;
 888
 889	/*
 890	 * Start using the new console output if this is the first
 891	 * console to come up.
 892	 */
 893	if (early_put_chars)
 894		early_put_chars = NULL;
 895
 896	/* Notify host of port being opened */
 897	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
 898
 899	return 0;
 900}
 901
 902static ssize_t show_port_name(struct device *dev,
 903			      struct device_attribute *attr, char *buffer)
 904{
 905	struct port *port;
 906
 907	port = dev_get_drvdata(dev);
 908
 909	return sprintf(buffer, "%s\n", port->name);
 910}
 911
 912static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
 913
 914static struct attribute *port_sysfs_entries[] = {
 915	&dev_attr_name.attr,
 916	NULL
 917};
 918
 919static struct attribute_group port_attribute_group = {
 920	.name = NULL,		/* put in device directory */
 921	.attrs = port_sysfs_entries,
 922};
 923
 924static int debugfs_open(struct inode *inode, struct file *filp)
 925{
 926	filp->private_data = inode->i_private;
 927	return 0;
 928}
 929
 930static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
 931			    size_t count, loff_t *offp)
 932{
 933	struct port *port;
 934	char *buf;
 935	ssize_t ret, out_offset, out_count;
 936
 937	out_count = 1024;
 938	buf = kmalloc(out_count, GFP_KERNEL);
 939	if (!buf)
 940		return -ENOMEM;
 941
 942	port = filp->private_data;
 943	out_offset = 0;
 944	out_offset += snprintf(buf + out_offset, out_count,
 945			       "name: %s\n", port->name ? port->name : "");
 946	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 947			       "guest_connected: %d\n", port->guest_connected);
 948	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 949			       "host_connected: %d\n", port->host_connected);
 950	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 951			       "outvq_full: %d\n", port->outvq_full);
 952	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 953			       "is_console: %s\n",
 954			       is_console_port(port) ? "yes" : "no");
 955	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 956			       "console_vtermno: %u\n", port->cons.vtermno);
 957
 958	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 959	kfree(buf);
 960	return ret;
 961}
 962
 963static const struct file_operations port_debugfs_ops = {
 964	.owner = THIS_MODULE,
 965	.open  = debugfs_open,
 966	.read  = debugfs_read,
 967};
 968
 969static void set_console_size(struct port *port, u16 rows, u16 cols)
 970{
 971	if (!port || !is_console_port(port))
 972		return;
 973
 974	port->cons.ws.ws_row = rows;
 975	port->cons.ws.ws_col = cols;
 976}
 977
 978static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
 979{
 980	struct port_buffer *buf;
 981	unsigned int nr_added_bufs;
 982	int ret;
 983
 984	nr_added_bufs = 0;
 985	do {
 986		buf = alloc_buf(PAGE_SIZE);
 987		if (!buf)
 988			break;
 989
 990		spin_lock_irq(lock);
 991		ret = add_inbuf(vq, buf);
 992		if (ret < 0) {
 993			spin_unlock_irq(lock);
 994			free_buf(buf);
 995			break;
 996		}
 997		nr_added_bufs++;
 998		spin_unlock_irq(lock);
 999	} while (ret > 0);
1000
1001	return nr_added_bufs;
1002}
1003
1004static int add_port(struct ports_device *portdev, u32 id)
1005{
1006	char debugfs_name[16];
1007	struct port *port;
1008	struct port_buffer *buf;
1009	dev_t devt;
1010	unsigned int nr_added_bufs;
1011	int err;
1012
1013	port = kmalloc(sizeof(*port), GFP_KERNEL);
1014	if (!port) {
1015		err = -ENOMEM;
1016		goto fail;
1017	}
1018
1019	port->portdev = portdev;
1020	port->id = id;
1021
1022	port->name = NULL;
1023	port->inbuf = NULL;
1024	port->cons.hvc = NULL;
1025
1026	port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1027
1028	port->host_connected = port->guest_connected = false;
1029
1030	port->outvq_full = false;
1031
1032	port->in_vq = portdev->in_vqs[port->id];
1033	port->out_vq = portdev->out_vqs[port->id];
1034
1035	cdev_init(&port->cdev, &port_fops);
1036
1037	devt = MKDEV(portdev->chr_major, id);
1038	err = cdev_add(&port->cdev, devt, 1);
1039	if (err < 0) {
1040		dev_err(&port->portdev->vdev->dev,
1041			"Error %d adding cdev for port %u\n", err, id);
1042		goto free_port;
1043	}
1044	port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1045				  devt, port, "vport%up%u",
1046				  port->portdev->drv_index, id);
1047	if (IS_ERR(port->dev)) {
1048		err = PTR_ERR(port->dev);
1049		dev_err(&port->portdev->vdev->dev,
1050			"Error %d creating device for port %u\n",
1051			err, id);
1052		goto free_cdev;
1053	}
1054
1055	spin_lock_init(&port->inbuf_lock);
1056	spin_lock_init(&port->outvq_lock);
1057	init_waitqueue_head(&port->waitqueue);
1058
1059	/* Fill the in_vq with buffers so the host can send us data. */
1060	nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1061	if (!nr_added_bufs) {
1062		dev_err(port->dev, "Error allocating inbufs\n");
1063		err = -ENOMEM;
1064		goto free_device;
1065	}
1066
1067	/*
1068	 * If we're not using multiport support, this has to be a console port
1069	 */
1070	if (!use_multiport(port->portdev)) {
1071		err = init_port_console(port);
1072		if (err)
1073			goto free_inbufs;
1074	}
1075
1076	spin_lock_irq(&portdev->ports_lock);
1077	list_add_tail(&port->list, &port->portdev->ports);
1078	spin_unlock_irq(&portdev->ports_lock);
1079
1080	/*
1081	 * Tell the Host we're set so that it can send us various
1082	 * configuration parameters for this port (eg, port name,
1083	 * caching, whether this is a console port, etc.)
1084	 */
1085	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1086
1087	if (pdrvdata.debugfs_dir) {
1088		/*
1089		 * Finally, create the debugfs file that we can use to
1090		 * inspect a port's state at any time
1091		 */
1092		sprintf(debugfs_name, "vport%up%u",
1093			port->portdev->drv_index, id);
1094		port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1095							 pdrvdata.debugfs_dir,
1096							 port,
1097							 &port_debugfs_ops);
1098	}
1099	return 0;
1100
1101free_inbufs:
1102	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1103		free_buf(buf);
1104free_device:
1105	device_destroy(pdrvdata.class, port->dev->devt);
1106free_cdev:
1107	cdev_del(&port->cdev);
1108free_port:
1109	kfree(port);
1110fail:
1111	/* The host might want to notify management sw about port add failure */
1112	__send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1113	return err;
1114}
1115
1116/* Remove all port-specific data. */
1117static int remove_port(struct port *port)
1118{
1119	struct port_buffer *buf;
1120
1121	if (port->guest_connected) {
1122		port->guest_connected = false;
1123		port->host_connected = false;
1124		wake_up_interruptible(&port->waitqueue);
1125		send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
1126	}
1127
1128	spin_lock_irq(&port->portdev->ports_lock);
1129	list_del(&port->list);
1130	spin_unlock_irq(&port->portdev->ports_lock);
1131
1132	if (is_console_port(port)) {
1133		spin_lock_irq(&pdrvdata_lock);
1134		list_del(&port->cons.list);
1135		spin_unlock_irq(&pdrvdata_lock);
1136#if 0
1137		/*
1138		 * hvc_remove() not called as removing one hvc port
1139		 * results in other hvc ports getting frozen.
1140		 *
1141		 * Once this is resolved in hvc, this functionality
1142		 * will be enabled.  Till that is done, the -EPIPE
1143		 * return from get_chars() above will help
1144		 * hvc_console.c to clean up on ports we remove here.
1145		 */
1146		hvc_remove(port->cons.hvc);
1147#endif
1148	}
1149	sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1150	device_destroy(pdrvdata.class, port->dev->devt);
1151	cdev_del(&port->cdev);
1152
1153	/* Remove unused data this port might have received. */
1154	discard_port_data(port);
1155
1156	reclaim_consumed_buffers(port);
1157
1158	/* Remove buffers we queued up for the Host to send us data in. */
1159	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1160		free_buf(buf);
1161
1162	kfree(port->name);
1163
1164	debugfs_remove(port->debugfs_file);
1165
1166	kfree(port);
1167	return 0;
1168}
1169
1170/* Any private messages that the Host and Guest want to share */
1171static void handle_control_message(struct ports_device *portdev,
1172				   struct port_buffer *buf)
1173{
1174	struct virtio_console_control *cpkt;
1175	struct port *port;
1176	size_t name_size;
1177	int err;
1178
1179	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1180
1181	port = find_port_by_id(portdev, cpkt->id);
1182	if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
1183		/* No valid header at start of buffer.  Drop it. */
1184		dev_dbg(&portdev->vdev->dev,
1185			"Invalid index %u in control packet\n", cpkt->id);
1186		return;
1187	}
1188
1189	switch (cpkt->event) {
1190	case VIRTIO_CONSOLE_PORT_ADD:
1191		if (port) {
1192			dev_dbg(&portdev->vdev->dev,
1193				"Port %u already added\n", port->id);
1194			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1195			break;
1196		}
1197		if (cpkt->id >= portdev->config.max_nr_ports) {
1198			dev_warn(&portdev->vdev->dev,
1199				"Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1200				cpkt->id, portdev->config.max_nr_ports - 1);
1201			break;
1202		}
1203		add_port(portdev, cpkt->id);
1204		break;
1205	case VIRTIO_CONSOLE_PORT_REMOVE:
1206		remove_port(port);
1207		break;
1208	case VIRTIO_CONSOLE_CONSOLE_PORT:
1209		if (!cpkt->value)
1210			break;
1211		if (is_console_port(port))
1212			break;
1213
1214		init_port_console(port);
1215		/*
1216		 * Could remove the port here in case init fails - but
1217		 * have to notify the host first.
1218		 */
1219		break;
1220	case VIRTIO_CONSOLE_RESIZE: {
1221		struct {
1222			__u16 rows;
1223			__u16 cols;
1224		} size;
1225
1226		if (!is_console_port(port))
1227			break;
1228
1229		memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1230		       sizeof(size));
1231		set_console_size(port, size.rows, size.cols);
1232
1233		port->cons.hvc->irq_requested = 1;
1234		resize_console(port);
1235		break;
1236	}
1237	case VIRTIO_CONSOLE_PORT_OPEN:
1238		port->host_connected = cpkt->value;
1239		wake_up_interruptible(&port->waitqueue);
1240		/*
1241		 * If the host port got closed and the host had any
1242		 * unconsumed buffers, we'll be able to reclaim them
1243		 * now.
1244		 */
1245		spin_lock_irq(&port->outvq_lock);
1246		reclaim_consumed_buffers(port);
1247		spin_unlock_irq(&port->outvq_lock);
1248		break;
1249	case VIRTIO_CONSOLE_PORT_NAME:
1250		/*
1251		 * Skip the size of the header and the cpkt to get the size
1252		 * of the name that was sent
1253		 */
1254		name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1255
1256		port->name = kmalloc(name_size, GFP_KERNEL);
1257		if (!port->name) {
1258			dev_err(port->dev,
1259				"Not enough space to store port name\n");
1260			break;
1261		}
1262		strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1263			name_size - 1);
1264		port->name[name_size - 1] = 0;
1265
1266		/*
1267		 * Since we only have one sysfs attribute, 'name',
1268		 * create it only if we have a name for the port.
1269		 */
1270		err = sysfs_create_group(&port->dev->kobj,
1271					 &port_attribute_group);
1272		if (err) {
1273			dev_err(port->dev,
1274				"Error %d creating sysfs device attributes\n",
1275				err);
1276		} else {
1277			/*
1278			 * Generate a udev event so that appropriate
1279			 * symlinks can be created based on udev
1280			 * rules.
1281			 */
1282			kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1283		}
1284		break;
1285	}
1286}
1287
1288static void control_work_handler(struct work_struct *work)
1289{
1290	struct ports_device *portdev;
1291	struct virtqueue *vq;
1292	struct port_buffer *buf;
1293	unsigned int len;
1294
1295	portdev = container_of(work, struct ports_device, control_work);
1296	vq = portdev->c_ivq;
1297
1298	spin_lock(&portdev->cvq_lock);
1299	while ((buf = virtqueue_get_buf(vq, &len))) {
1300		spin_unlock(&portdev->cvq_lock);
1301
1302		buf->len = len;
1303		buf->offset = 0;
1304
1305		handle_control_message(portdev, buf);
1306
1307		spin_lock(&portdev->cvq_lock);
1308		if (add_inbuf(portdev->c_ivq, buf) < 0) {
1309			dev_warn(&portdev->vdev->dev,
1310				 "Error adding buffer to queue\n");
1311			free_buf(buf);
1312		}
1313	}
1314	spin_unlock(&portdev->cvq_lock);
1315}
1316
1317static void in_intr(struct virtqueue *vq)
1318{
1319	struct port *port;
1320	unsigned long flags;
1321
1322	port = find_port_by_vq(vq->vdev->priv, vq);
1323	if (!port)
1324		return;
1325
1326	spin_lock_irqsave(&port->inbuf_lock, flags);
1327	if (!port->inbuf)
1328		port->inbuf = get_inbuf(port);
1329
1330	/*
1331	 * Don't queue up data when port is closed.  This condition
1332	 * can be reached when a console port is not yet connected (no
1333	 * tty is spawned) and the host sends out data to console
1334	 * ports.  For generic serial ports, the host won't
1335	 * (shouldn't) send data till the guest is connected.
1336	 */
1337	if (!port->guest_connected)
1338		discard_port_data(port);
1339
1340	spin_unlock_irqrestore(&port->inbuf_lock, flags);
1341
1342	wake_up_interruptible(&port->waitqueue);
1343
1344	if (is_console_port(port) && hvc_poll(port->cons.hvc))
1345		hvc_kick();
1346}
1347
1348static void control_intr(struct virtqueue *vq)
1349{
1350	struct ports_device *portdev;
1351
1352	portdev = vq->vdev->priv;
1353	schedule_work(&portdev->control_work);
1354}
1355
1356static void config_intr(struct virtio_device *vdev)
1357{
1358	struct ports_device *portdev;
1359
1360	portdev = vdev->priv;
1361
1362	if (!use_multiport(portdev)) {
1363		struct port *port;
1364		u16 rows, cols;
1365
1366		vdev->config->get(vdev,
1367				  offsetof(struct virtio_console_config, cols),
1368				  &cols, sizeof(u16));
1369		vdev->config->get(vdev,
1370				  offsetof(struct virtio_console_config, rows),
1371				  &rows, sizeof(u16));
1372
1373		port = find_port_by_id(portdev, 0);
1374		set_console_size(port, rows, cols);
1375
1376		/*
1377		 * We'll use this way of resizing only for legacy
1378		 * support.  For newer userspace
1379		 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1380		 * to indicate console size changes so that it can be
1381		 * done per-port.
1382		 */
1383		resize_console(port);
1384	}
1385}
1386
1387static int init_vqs(struct ports_device *portdev)
1388{
1389	vq_callback_t **io_callbacks;
1390	char **io_names;
1391	struct virtqueue **vqs;
1392	u32 i, j, nr_ports, nr_queues;
1393	int err;
1394
1395	nr_ports = portdev->config.max_nr_ports;
1396	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1397
1398	vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1399	if (!vqs) {
1400		err = -ENOMEM;
1401		goto fail;
1402	}
1403	io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1404	if (!io_callbacks) {
1405		err = -ENOMEM;
1406		goto free_vqs;
1407	}
1408	io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1409	if (!io_names) {
1410		err = -ENOMEM;
1411		goto free_callbacks;
1412	}
1413	portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1414				  GFP_KERNEL);
1415	if (!portdev->in_vqs) {
1416		err = -ENOMEM;
1417		goto free_names;
1418	}
1419	portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1420				   GFP_KERNEL);
1421	if (!portdev->out_vqs) {
1422		err = -ENOMEM;
1423		goto free_invqs;
1424	}
1425
1426	/*
1427	 * For backward compat (newer host but older guest), the host
1428	 * spawns a console port first and also inits the vqs for port
1429	 * 0 before others.
1430	 */
1431	j = 0;
1432	io_callbacks[j] = in_intr;
1433	io_callbacks[j + 1] = NULL;
1434	io_names[j] = "input";
1435	io_names[j + 1] = "output";
1436	j += 2;
1437
1438	if (use_multiport(portdev)) {
1439		io_callbacks[j] = control_intr;
1440		io_callbacks[j + 1] = NULL;
1441		io_names[j] = "control-i";
1442		io_names[j + 1] = "control-o";
1443
1444		for (i = 1; i < nr_ports; i++) {
1445			j += 2;
1446			io_callbacks[j] = in_intr;
1447			io_callbacks[j + 1] = NULL;
1448			io_names[j] = "input";
1449			io_names[j + 1] = "output";
1450		}
1451	}
1452	/* Find the queues. */
1453	err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1454					      io_callbacks,
1455					      (const char **)io_names);
1456	if (err)
1457		goto free_outvqs;
1458
1459	j = 0;
1460	portdev->in_vqs[0] = vqs[0];
1461	portdev->out_vqs[0] = vqs[1];
1462	j += 2;
1463	if (use_multiport(portdev)) {
1464		portdev->c_ivq = vqs[j];
1465		portdev->c_ovq = vqs[j + 1];
1466
1467		for (i = 1; i < nr_ports; i++) {
1468			j += 2;
1469			portdev->in_vqs[i] = vqs[j];
1470			portdev->out_vqs[i] = vqs[j + 1];
1471		}
1472	}
1473	kfree(io_callbacks);
1474	kfree(io_names);
1475	kfree(vqs);
1476
1477	return 0;
1478
1479free_names:
1480	kfree(io_names);
1481free_callbacks:
1482	kfree(io_callbacks);
1483free_outvqs:
1484	kfree(portdev->out_vqs);
1485free_invqs:
1486	kfree(portdev->in_vqs);
1487free_vqs:
1488	kfree(vqs);
1489fail:
1490	return err;
1491}
1492
1493static const struct file_operations portdev_fops = {
1494	.owner = THIS_MODULE,
1495};
1496
1497/*
1498 * Once we're further in boot, we get probed like any other virtio
1499 * device.
1500 *
1501 * If the host also supports multiple console ports, we check the
1502 * config space to see how many ports the host has spawned.  We
1503 * initialize each port found.
1504 */
1505static int __devinit virtcons_probe(struct virtio_device *vdev)
1506{
1507	struct ports_device *portdev;
1508	int err;
1509	bool multiport;
1510
1511	portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1512	if (!portdev) {
1513		err = -ENOMEM;
1514		goto fail;
1515	}
1516
1517	/* Attach this portdev to this virtio_device, and vice-versa. */
1518	portdev->vdev = vdev;
1519	vdev->priv = portdev;
1520
1521	spin_lock_irq(&pdrvdata_lock);
1522	portdev->drv_index = pdrvdata.index++;
1523	spin_unlock_irq(&pdrvdata_lock);
1524
1525	portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1526					     &portdev_fops);
1527	if (portdev->chr_major < 0) {
1528		dev_err(&vdev->dev,
1529			"Error %d registering chrdev for device %u\n",
1530			portdev->chr_major, portdev->drv_index);
1531		err = portdev->chr_major;
1532		goto free;
1533	}
1534
1535	multiport = false;
1536	portdev->config.max_nr_ports = 1;
1537	if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
1538		multiport = true;
1539		vdev->features[0] |= 1 << VIRTIO_CONSOLE_F_MULTIPORT;
1540
1541		vdev->config->get(vdev, offsetof(struct virtio_console_config,
1542						 max_nr_ports),
1543				  &portdev->config.max_nr_ports,
1544				  sizeof(portdev->config.max_nr_ports));
1545	}
1546
1547	/* Let the Host know we support multiple ports.*/
1548	vdev->config->finalize_features(vdev);
1549
1550	err = init_vqs(portdev);
1551	if (err < 0) {
1552		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
1553		goto free_chrdev;
1554	}
1555
1556	spin_lock_init(&portdev->ports_lock);
1557	INIT_LIST_HEAD(&portdev->ports);
1558
1559	if (multiport) {
1560		unsigned int nr_added_bufs;
1561
1562		spin_lock_init(&portdev->cvq_lock);
1563		INIT_WORK(&portdev->control_work, &control_work_handler);
1564
1565		nr_added_bufs = fill_queue(portdev->c_ivq, &portdev->cvq_lock);
1566		if (!nr_added_bufs) {
1567			dev_err(&vdev->dev,
1568				"Error allocating buffers for control queue\n");
1569			err = -ENOMEM;
1570			goto free_vqs;
1571		}
1572	} else {
1573		/*
1574		 * For backward compatibility: Create a console port
1575		 * if we're running on older host.
1576		 */
1577		add_port(portdev, 0);
1578	}
1579
1580	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1581			   VIRTIO_CONSOLE_DEVICE_READY, 1);
1582	return 0;
1583
1584free_vqs:
1585	/* The host might want to notify mgmt sw about device add failure */
1586	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1587			   VIRTIO_CONSOLE_DEVICE_READY, 0);
1588	vdev->config->del_vqs(vdev);
1589	kfree(portdev->in_vqs);
1590	kfree(portdev->out_vqs);
1591free_chrdev:
1592	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1593free:
1594	kfree(portdev);
1595fail:
1596	return err;
1597}
1598
1599static void virtcons_remove(struct virtio_device *vdev)
1600{
1601	struct ports_device *portdev;
1602	struct port *port, *port2;
1603	struct port_buffer *buf;
1604	unsigned int len;
1605
1606	portdev = vdev->priv;
1607
1608	cancel_work_sync(&portdev->control_work);
1609
1610	list_for_each_entry_safe(port, port2, &portdev->ports, list)
1611		remove_port(port);
1612
1613	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1614
1615	while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1616		free_buf(buf);
1617
1618	while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1619		free_buf(buf);
1620
1621	vdev->config->del_vqs(vdev);
1622	kfree(portdev->in_vqs);
1623	kfree(portdev->out_vqs);
1624
1625	kfree(portdev);
1626}
1627
1628static struct virtio_device_id id_table[] = {
1629	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
1630	{ 0 },
1631};
1632
1633static unsigned int features[] = {
1634	VIRTIO_CONSOLE_F_SIZE,
1635	VIRTIO_CONSOLE_F_MULTIPORT,
1636};
1637
1638static struct virtio_driver virtio_console = {
1639	.feature_table = features,
1640	.feature_table_size = ARRAY_SIZE(features),
1641	.driver.name =	KBUILD_MODNAME,
1642	.driver.owner =	THIS_MODULE,
1643	.id_table =	id_table,
1644	.probe =	virtcons_probe,
1645	.remove =	virtcons_remove,
1646	.config_changed = config_intr,
1647};
1648
1649static int __init init(void)
1650{
1651	int err;
1652
1653	pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
1654	if (IS_ERR(pdrvdata.class)) {
1655		err = PTR_ERR(pdrvdata.class);
1656		pr_err("Error %d creating virtio-ports class\n", err);
1657		return err;
1658	}
1659
1660	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
1661	if (!pdrvdata.debugfs_dir) {
1662		pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
1663			   PTR_ERR(pdrvdata.debugfs_dir));
1664	}
1665	INIT_LIST_HEAD(&pdrvdata.consoles);
1666
1667	return register_virtio_driver(&virtio_console);
1668}
1669
1670static void __exit fini(void)
1671{
1672	unregister_virtio_driver(&virtio_console);
1673
1674	class_destroy(pdrvdata.class);
1675	if (pdrvdata.debugfs_dir)
1676		debugfs_remove_recursive(pdrvdata.debugfs_dir);
1677}
1678module_init(init);
1679module_exit(fini);
1680
1681MODULE_DEVICE_TABLE(virtio, id_table);
1682MODULE_DESCRIPTION("Virtio console driver");
1683MODULE_LICENSE("GPL");