1/*
   2 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
   3 * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
   4 * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 */
  20#include <linux/cdev.h>
  21#include <linux/debugfs.h>
 
  22#include <linux/device.h>
  23#include <linux/err.h>
 
  24#include <linux/fs.h>
 
 
  25#include <linux/init.h>
  26#include <linux/list.h>
  27#include <linux/poll.h>
  28#include <linux/sched.h>
  29#include <linux/slab.h>
  30#include <linux/spinlock.h>
  31#include <linux/virtio.h>
  32#include <linux/virtio_console.h>
  33#include <linux/wait.h>
  34#include <linux/workqueue.h>
 
 
 
  35#include "../tty/hvc/hvc_console.h"
  36
 
 
  37/*
  38 * This is a global struct for storing common data for all the devices
  39 * this driver handles.
  40 *
  41 * Mainly, it has a linked list for all the consoles in one place so
  42 * that callbacks from hvc for get_chars(), put_chars() work properly
  43 * across multiple devices and multiple ports per device.
  44 */
  45struct ports_driver_data {
  46	/* Used for registering chardevs */
  47	struct class *class;
  48
  49	/* Used for exporting per-port information to debugfs */
  50	struct dentry *debugfs_dir;
  51
  52	/* List of all the devices we're handling */
  53	struct list_head portdevs;
  54
  55	/* Number of devices this driver is handling */
  56	unsigned int index;
  57
  58	/*
  59	 * This is used to keep track of the number of hvc consoles
  60	 * spawned by this driver.  This number is given as the first
  61	 * argument to hvc_alloc().  To correctly map an initial
  62	 * console spawned via hvc_instantiate to the console being
  63	 * hooked up via hvc_alloc, we need to pass the same vtermno.
  64	 *
  65	 * We also just assume the first console being initialised was
  66	 * the first one that got used as the initial console.
  67	 */
  68	unsigned int next_vtermno;
  69
  70	/* All the console devices handled by this driver */
  71	struct list_head consoles;
  72};
  73static struct ports_driver_data pdrvdata;
  74
  75DEFINE_SPINLOCK(pdrvdata_lock);
 
  76
  77/* This struct holds information that's relevant only for console ports */
  78struct console {
  79	/* We'll place all consoles in a list in the pdrvdata struct */
  80	struct list_head list;
  81
  82	/* The hvc device associated with this console port */
  83	struct hvc_struct *hvc;
  84
  85	/* The size of the console */
  86	struct winsize ws;
  87
  88	/*
  89	 * This number identifies the number that we used to register
  90	 * with hvc in hvc_instantiate() and hvc_alloc(); this is the
  91	 * number passed on by the hvc callbacks to us to
  92	 * differentiate between the other console ports handled by
  93	 * this driver
  94	 */
  95	u32 vtermno;
  96};
  97
  98struct port_buffer {
  99	char *buf;
 100
 101	/* size of the buffer in *buf above */
 102	size_t size;
 103
 104	/* used length of the buffer */
 105	size_t len;
 106	/* offset in the buf from which to consume data */
 107	size_t offset;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 108};
 109
 110/*
 111 * This is a per-device struct that stores data common to all the
 112 * ports for that device (vdev->priv).
 113 */
 114struct ports_device {
 115	/* Next portdev in the list, head is in the pdrvdata struct */
 116	struct list_head list;
 117
 118	/*
 119	 * Workqueue handlers where we process deferred work after
 120	 * notification
 121	 */
 122	struct work_struct control_work;
 123
 124	struct list_head ports;
 125
 126	/* To protect the list of ports */
 127	spinlock_t ports_lock;
 128
 129	/* To protect the vq operations for the control channel */
 130	spinlock_t cvq_lock;
 
 131
 132	/* The current config space is stored here */
 133	struct virtio_console_config config;
 134
 135	/* The virtio device we're associated with */
 136	struct virtio_device *vdev;
 137
 138	/*
 139	 * A couple of virtqueues for the control channel: one for
 140	 * guest->host transfers, one for host->guest transfers
 141	 */
 142	struct virtqueue *c_ivq, *c_ovq;
 143
 144	/* Array of per-port IO virtqueues */
 145	struct virtqueue **in_vqs, **out_vqs;
 146
 147	/* Used for numbering devices for sysfs and debugfs */
 148	unsigned int drv_index;
 149
 150	/* Major number for this device.  Ports will be created as minors. */
 151	int chr_major;
 152};
 153
 
 
 
 
 154/* This struct holds the per-port data */
 155struct port {
 156	/* Next port in the list, head is in the ports_device */
 157	struct list_head list;
 158
 159	/* Pointer to the parent virtio_console device */
 160	struct ports_device *portdev;
 161
 162	/* The current buffer from which data has to be fed to readers */
 163	struct port_buffer *inbuf;
 164
 165	/*
 166	 * To protect the operations on the in_vq associated with this
 167	 * port.  Has to be a spinlock because it can be called from
 168	 * interrupt context (get_char()).
 169	 */
 170	spinlock_t inbuf_lock;
 171
 172	/* Protect the operations on the out_vq. */
 173	spinlock_t outvq_lock;
 174
 175	/* The IO vqs for this port */
 176	struct virtqueue *in_vq, *out_vq;
 177
 178	/* File in the debugfs directory that exposes this port's information */
 179	struct dentry *debugfs_file;
 180
 181	/*
 
 
 
 
 
 
 
 182	 * The entries in this struct will be valid if this port is
 183	 * hooked up to an hvc console
 184	 */
 185	struct console cons;
 186
 187	/* Each port associates with a separate char device */
 188	struct cdev *cdev;
 189	struct device *dev;
 190
 191	/* Reference-counting to handle port hot-unplugs and file operations */
 192	struct kref kref;
 193
 194	/* A waitqueue for poll() or blocking read operations */
 195	wait_queue_head_t waitqueue;
 196
 197	/* The 'name' of the port that we expose via sysfs properties */
 198	char *name;
 199
 200	/* We can notify apps of host connect / disconnect events via SIGIO */
 201	struct fasync_struct *async_queue;
 202
 203	/* The 'id' to identify the port with the Host */
 204	u32 id;
 205
 206	bool outvq_full;
 207
 208	/* Is the host device open */
 209	bool host_connected;
 210
 211	/* We should allow only one process to open a port */
 212	bool guest_connected;
 213};
 214
 215/* This is the very early arch-specified put chars function. */
 216static int (*early_put_chars)(u32, const char *, int);
 217
 218static struct port *find_port_by_vtermno(u32 vtermno)
 219{
 220	struct port *port;
 221	struct console *cons;
 222	unsigned long flags;
 223
 224	spin_lock_irqsave(&pdrvdata_lock, flags);
 225	list_for_each_entry(cons, &pdrvdata.consoles, list) {
 226		if (cons->vtermno == vtermno) {
 227			port = container_of(cons, struct port, cons);
 228			goto out;
 229		}
 230	}
 231	port = NULL;
 232out:
 233	spin_unlock_irqrestore(&pdrvdata_lock, flags);
 234	return port;
 235}
 236
 237static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
 238						 dev_t dev)
 239{
 240	struct port *port;
 241	unsigned long flags;
 242
 243	spin_lock_irqsave(&portdev->ports_lock, flags);
 244	list_for_each_entry(port, &portdev->ports, list)
 245		if (port->cdev->dev == dev)
 
 246			goto out;
 
 
 247	port = NULL;
 248out:
 249	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 250
 251	return port;
 252}
 253
 254static struct port *find_port_by_devt(dev_t dev)
 255{
 256	struct ports_device *portdev;
 257	struct port *port;
 258	unsigned long flags;
 259
 260	spin_lock_irqsave(&pdrvdata_lock, flags);
 261	list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
 262		port = find_port_by_devt_in_portdev(portdev, dev);
 263		if (port)
 264			goto out;
 265	}
 266	port = NULL;
 267out:
 268	spin_unlock_irqrestore(&pdrvdata_lock, flags);
 269	return port;
 270}
 271
 272static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
 273{
 274	struct port *port;
 275	unsigned long flags;
 276
 277	spin_lock_irqsave(&portdev->ports_lock, flags);
 278	list_for_each_entry(port, &portdev->ports, list)
 279		if (port->id == id)
 280			goto out;
 281	port = NULL;
 282out:
 283	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 284
 285	return port;
 286}
 287
 288static struct port *find_port_by_vq(struct ports_device *portdev,
 289				    struct virtqueue *vq)
 290{
 291	struct port *port;
 292	unsigned long flags;
 293
 294	spin_lock_irqsave(&portdev->ports_lock, flags);
 295	list_for_each_entry(port, &portdev->ports, list)
 296		if (port->in_vq == vq || port->out_vq == vq)
 297			goto out;
 298	port = NULL;
 299out:
 300	spin_unlock_irqrestore(&portdev->ports_lock, flags);
 301	return port;
 302}
 303
 304static bool is_console_port(struct port *port)
 305{
 306	if (port->cons.hvc)
 307		return true;
 308	return false;
 309}
 310
 
 
 
 
 
 311static inline bool use_multiport(struct ports_device *portdev)
 312{
 313	/*
 314	 * This condition can be true when put_chars is called from
 315	 * early_init
 316	 */
 317	if (!portdev->vdev)
 318		return 0;
 319	return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 320}
 321
 322static void free_buf(struct port_buffer *buf)
 
 
 
 323{
 324	kfree(buf->buf);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 325	kfree(buf);
 326}
 327
 328static struct port_buffer *alloc_buf(size_t buf_size)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 329{
 330	struct port_buffer *buf;
 331
 332	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
 
 
 
 
 
 
 
 333	if (!buf)
 334		goto fail;
 335	buf->buf = kzalloc(buf_size, GFP_KERNEL);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 336	if (!buf->buf)
 337		goto free_buf;
 338	buf->len = 0;
 339	buf->offset = 0;
 340	buf->size = buf_size;
 341	return buf;
 342
 343free_buf:
 344	kfree(buf);
 345fail:
 346	return NULL;
 347}
 348
 349/* Callers should take appropriate locks */
 350static void *get_inbuf(struct port *port)
 351{
 352	struct port_buffer *buf;
 353	struct virtqueue *vq;
 354	unsigned int len;
 355
 356	vq = port->in_vq;
 357	buf = virtqueue_get_buf(vq, &len);
 
 
 358	if (buf) {
 359		buf->len = len;
 360		buf->offset = 0;
 
 361	}
 362	return buf;
 363}
 364
 365/*
 366 * Create a scatter-gather list representing our input buffer and put
 367 * it in the queue.
 368 *
 369 * Callers should take appropriate locks.
 370 */
 371static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 372{
 373	struct scatterlist sg[1];
 374	int ret;
 375
 376	sg_init_one(sg, buf->buf, buf->size);
 377
 378	ret = virtqueue_add_buf(vq, sg, 0, 1, buf);
 379	virtqueue_kick(vq);
 
 
 380	return ret;
 381}
 382
 383/* Discard any unread data this port has. Callers lockers. */
 384static void discard_port_data(struct port *port)
 385{
 386	struct port_buffer *buf;
 387	struct virtqueue *vq;
 388	unsigned int len;
 389	int ret;
 390
 391	if (!port->portdev) {
 392		/* Device has been unplugged.  vqs are already gone. */
 393		return;
 394	}
 395	vq = port->in_vq;
 396	if (port->inbuf)
 397		buf = port->inbuf;
 398	else
 399		buf = virtqueue_get_buf(vq, &len);
 400
 401	ret = 0;
 402	while (buf) {
 403		if (add_inbuf(vq, buf) < 0) {
 404			ret++;
 405			free_buf(buf);
 
 406		}
 407		buf = virtqueue_get_buf(vq, &len);
 
 408	}
 409	port->inbuf = NULL;
 410	if (ret)
 411		dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
 412			 ret);
 413}
 414
 415static bool port_has_data(struct port *port)
 416{
 417	unsigned long flags;
 418	bool ret;
 419
 
 420	spin_lock_irqsave(&port->inbuf_lock, flags);
 421	if (port->inbuf) {
 422		ret = true;
 423		goto out;
 424	}
 425	port->inbuf = get_inbuf(port);
 426	if (port->inbuf) {
 427		ret = true;
 428		goto out;
 429	}
 430	ret = false;
 431out:
 432	spin_unlock_irqrestore(&port->inbuf_lock, flags);
 433	return ret;
 434}
 435
 436static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
 437				  unsigned int event, unsigned int value)
 438{
 439	struct scatterlist sg[1];
 440	struct virtio_console_control cpkt;
 441	struct virtqueue *vq;
 442	unsigned int len;
 443
 444	if (!use_multiport(portdev))
 445		return 0;
 446
 447	cpkt.id = port_id;
 448	cpkt.event = event;
 449	cpkt.value = value;
 450
 451	vq = portdev->c_ovq;
 452
 453	sg_init_one(sg, &cpkt, sizeof(cpkt));
 454	if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
 
 
 455		virtqueue_kick(vq);
 456		while (!virtqueue_get_buf(vq, &len))
 
 457			cpu_relax();
 458	}
 
 459	return 0;
 460}
 461
 462static ssize_t send_control_msg(struct port *port, unsigned int event,
 463				unsigned int value)
 464{
 465	/* Did the port get unplugged before userspace closed it? */
 466	if (port->portdev)
 467		return __send_control_msg(port->portdev, port->id, event, value);
 468	return 0;
 469}
 470
 
 471/* Callers must take the port->outvq_lock */
 472static void reclaim_consumed_buffers(struct port *port)
 473{
 474	void *buf;
 475	unsigned int len;
 476
 477	if (!port->portdev) {
 478		/* Device has been unplugged.  vqs are already gone. */
 479		return;
 480	}
 481	while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
 482		kfree(buf);
 483		port->outvq_full = false;
 484	}
 485}
 486
 487static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
 488			bool nonblock)
 
 489{
 490	struct scatterlist sg[1];
 491	struct virtqueue *out_vq;
 492	ssize_t ret;
 493	unsigned long flags;
 494	unsigned int len;
 495
 496	out_vq = port->out_vq;
 497
 498	spin_lock_irqsave(&port->outvq_lock, flags);
 499
 500	reclaim_consumed_buffers(port);
 501
 502	sg_init_one(sg, in_buf, in_count);
 503	ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf);
 504
 505	/* Tell Host to go! */
 506	virtqueue_kick(out_vq);
 507
 508	if (ret < 0) {
 509		in_count = 0;
 510		goto done;
 511	}
 512
 513	if (ret == 0)
 514		port->outvq_full = true;
 515
 516	if (nonblock)
 517		goto done;
 518
 519	/*
 520	 * Wait till the host acknowledges it pushed out the data we
 521	 * sent.  This is done for data from the hvc_console; the tty
 522	 * operations are performed with spinlocks held so we can't
 523	 * sleep here.  An alternative would be to copy the data to a
 524	 * buffer and relax the spinning requirement.  The downside is
 525	 * we need to kmalloc a GFP_ATOMIC buffer each time the
 526	 * console driver writes something out.
 527	 */
 528	while (!virtqueue_get_buf(out_vq, &len))
 
 529		cpu_relax();
 530done:
 531	spin_unlock_irqrestore(&port->outvq_lock, flags);
 
 
 532	/*
 533	 * We're expected to return the amount of data we wrote -- all
 534	 * of it
 535	 */
 536	return in_count;
 537}
 538
 539/*
 540 * Give out the data that's requested from the buffer that we have
 541 * queued up.
 542 */
 543static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
 544			    bool to_user)
 545{
 546	struct port_buffer *buf;
 547	unsigned long flags;
 548
 549	if (!out_count || !port_has_data(port))
 550		return 0;
 551
 552	buf = port->inbuf;
 553	out_count = min(out_count, buf->len - buf->offset);
 554
 555	if (to_user) {
 556		ssize_t ret;
 557
 558		ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
 559		if (ret)
 560			return -EFAULT;
 561	} else {
 562		memcpy(out_buf, buf->buf + buf->offset, out_count);
 563	}
 564
 565	buf->offset += out_count;
 566
 567	if (buf->offset == buf->len) {
 568		/*
 569		 * We're done using all the data in this buffer.
 570		 * Re-queue so that the Host can send us more data.
 571		 */
 572		spin_lock_irqsave(&port->inbuf_lock, flags);
 573		port->inbuf = NULL;
 574
 575		if (add_inbuf(port->in_vq, buf) < 0)
 576			dev_warn(port->dev, "failed add_buf\n");
 577
 578		spin_unlock_irqrestore(&port->inbuf_lock, flags);
 579	}
 580	/* Return the number of bytes actually copied */
 581	return out_count;
 582}
 583
 584/* The condition that must be true for polling to end */
 585static bool will_read_block(struct port *port)
 586{
 587	if (!port->guest_connected) {
 588		/* Port got hot-unplugged. Let's exit. */
 589		return false;
 590	}
 591	return !port_has_data(port) && port->host_connected;
 592}
 593
 594static bool will_write_block(struct port *port)
 595{
 596	bool ret;
 597
 598	if (!port->guest_connected) {
 599		/* Port got hot-unplugged. Let's exit. */
 600		return false;
 601	}
 602	if (!port->host_connected)
 603		return true;
 604
 605	spin_lock_irq(&port->outvq_lock);
 606	/*
 607	 * Check if the Host has consumed any buffers since we last
 608	 * sent data (this is only applicable for nonblocking ports).
 609	 */
 610	reclaim_consumed_buffers(port);
 611	ret = port->outvq_full;
 612	spin_unlock_irq(&port->outvq_lock);
 613
 614	return ret;
 615}
 616
 617static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
 618			      size_t count, loff_t *offp)
 619{
 620	struct port *port;
 621	ssize_t ret;
 622
 623	port = filp->private_data;
 624
 
 
 
 
 625	if (!port_has_data(port)) {
 626		/*
 627		 * If nothing's connected on the host just return 0 in
 628		 * case of list_empty; this tells the userspace app
 629		 * that there's no connection
 630		 */
 631		if (!port->host_connected)
 632			return 0;
 633		if (filp->f_flags & O_NONBLOCK)
 634			return -EAGAIN;
 635
 636		ret = wait_event_interruptible(port->waitqueue,
 637					       !will_read_block(port));
 638		if (ret < 0)
 639			return ret;
 640	}
 641	/* Port got hot-unplugged. */
 642	if (!port->guest_connected)
 643		return -ENODEV;
 644	/*
 645	 * We could've received a disconnection message while we were
 646	 * waiting for more data.
 647	 *
 648	 * This check is not clubbed in the if() statement above as we
 649	 * might receive some data as well as the host could get
 650	 * disconnected after we got woken up from our wait.  So we
 651	 * really want to give off whatever data we have and only then
 652	 * check for host_connected.
 653	 */
 654	if (!port_has_data(port) && !port->host_connected)
 655		return 0;
 656
 657	return fill_readbuf(port, ubuf, count, true);
 658}
 659
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 660static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 661			       size_t count, loff_t *offp)
 662{
 663	struct port *port;
 664	char *buf;
 665	ssize_t ret;
 666	bool nonblock;
 
 667
 668	/* Userspace could be out to fool us */
 669	if (!count)
 670		return 0;
 671
 672	port = filp->private_data;
 673
 674	nonblock = filp->f_flags & O_NONBLOCK;
 675
 676	if (will_write_block(port)) {
 677		if (nonblock)
 678			return -EAGAIN;
 679
 680		ret = wait_event_interruptible(port->waitqueue,
 681					       !will_write_block(port));
 682		if (ret < 0)
 683			return ret;
 684	}
 685	/* Port got hot-unplugged. */
 686	if (!port->guest_connected)
 687		return -ENODEV;
 688
 689	count = min((size_t)(32 * 1024), count);
 690
 691	buf = kmalloc(count, GFP_KERNEL);
 692	if (!buf)
 693		return -ENOMEM;
 694
 695	ret = copy_from_user(buf, ubuf, count);
 696	if (ret) {
 697		ret = -EFAULT;
 698		goto free_buf;
 699	}
 700
 701	/*
 702	 * We now ask send_buf() to not spin for generic ports -- we
 703	 * can re-use the same code path that non-blocking file
 704	 * descriptors take for blocking file descriptors since the
 705	 * wait is already done and we're certain the write will go
 706	 * through to the host.
 707	 */
 708	nonblock = true;
 709	ret = send_buf(port, buf, count, nonblock);
 
 710
 711	if (nonblock && ret > 0)
 712		goto out;
 713
 714free_buf:
 715	kfree(buf);
 716out:
 717	return ret;
 718}
 719
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 720static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
 721{
 722	struct port *port;
 723	unsigned int ret;
 724
 725	port = filp->private_data;
 726	poll_wait(filp, &port->waitqueue, wait);
 727
 728	if (!port->guest_connected) {
 729		/* Port got unplugged */
 730		return POLLHUP;
 731	}
 732	ret = 0;
 733	if (!will_read_block(port))
 734		ret |= POLLIN | POLLRDNORM;
 735	if (!will_write_block(port))
 736		ret |= POLLOUT;
 737	if (!port->host_connected)
 738		ret |= POLLHUP;
 739
 740	return ret;
 741}
 742
 743static void remove_port(struct kref *kref);
 744
 745static int port_fops_release(struct inode *inode, struct file *filp)
 746{
 747	struct port *port;
 748
 749	port = filp->private_data;
 750
 751	/* Notify host of port being closed */
 752	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
 753
 754	spin_lock_irq(&port->inbuf_lock);
 755	port->guest_connected = false;
 756
 757	discard_port_data(port);
 758
 759	spin_unlock_irq(&port->inbuf_lock);
 760
 761	spin_lock_irq(&port->outvq_lock);
 762	reclaim_consumed_buffers(port);
 763	spin_unlock_irq(&port->outvq_lock);
 764
 
 765	/*
 766	 * Locks aren't necessary here as a port can't be opened after
 767	 * unplug, and if a port isn't unplugged, a kref would already
 768	 * exist for the port.  Plus, taking ports_lock here would
 769	 * create a dependency on other locks taken by functions
 770	 * inside remove_port if we're the last holder of the port,
 771	 * creating many problems.
 772	 */
 773	kref_put(&port->kref, remove_port);
 774
 775	return 0;
 776}
 777
 778static int port_fops_open(struct inode *inode, struct file *filp)
 779{
 780	struct cdev *cdev = inode->i_cdev;
 781	struct port *port;
 782	int ret;
 783
 
 784	port = find_port_by_devt(cdev->dev);
 
 
 
 
 785	filp->private_data = port;
 786
 787	/* Prevent against a port getting hot-unplugged at the same time */
 788	spin_lock_irq(&port->portdev->ports_lock);
 789	kref_get(&port->kref);
 790	spin_unlock_irq(&port->portdev->ports_lock);
 791
 792	/*
 793	 * Don't allow opening of console port devices -- that's done
 794	 * via /dev/hvc
 795	 */
 796	if (is_console_port(port)) {
 797		ret = -ENXIO;
 798		goto out;
 799	}
 800
 801	/* Allow only one process to open a particular port at a time */
 802	spin_lock_irq(&port->inbuf_lock);
 803	if (port->guest_connected) {
 804		spin_unlock_irq(&port->inbuf_lock);
 805		ret = -EMFILE;
 806		goto out;
 807	}
 808
 809	port->guest_connected = true;
 810	spin_unlock_irq(&port->inbuf_lock);
 811
 812	spin_lock_irq(&port->outvq_lock);
 813	/*
 814	 * There might be a chance that we missed reclaiming a few
 815	 * buffers in the window of the port getting previously closed
 816	 * and opening now.
 817	 */
 818	reclaim_consumed_buffers(port);
 819	spin_unlock_irq(&port->outvq_lock);
 820
 821	nonseekable_open(inode, filp);
 822
 823	/* Notify host of port being opened */
 824	send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
 825
 826	return 0;
 827out:
 828	kref_put(&port->kref, remove_port);
 829	return ret;
 830}
 831
 832static int port_fops_fasync(int fd, struct file *filp, int mode)
 833{
 834	struct port *port;
 835
 836	port = filp->private_data;
 837	return fasync_helper(fd, filp, mode, &port->async_queue);
 838}
 839
 840/*
 841 * The file operations that we support: programs in the guest can open
 842 * a console device, read from it, write to it, poll for data and
 843 * close it.  The devices are at
 844 *   /dev/vport<device number>p<port number>
 845 */
 846static const struct file_operations port_fops = {
 847	.owner = THIS_MODULE,
 848	.open  = port_fops_open,
 849	.read  = port_fops_read,
 850	.write = port_fops_write,
 
 851	.poll  = port_fops_poll,
 852	.release = port_fops_release,
 853	.fasync = port_fops_fasync,
 854	.llseek = no_llseek,
 855};
 856
 857/*
 858 * The put_chars() callback is pretty straightforward.
 859 *
 860 * We turn the characters into a scatter-gather list, add it to the
 861 * output queue and then kick the Host.  Then we sit here waiting for
 862 * it to finish: inefficient in theory, but in practice
 863 * implementations will do it immediately (lguest's Launcher does).
 864 */
 865static int put_chars(u32 vtermno, const char *buf, int count)
 866{
 867	struct port *port;
 
 868
 869	if (unlikely(early_put_chars))
 870		return early_put_chars(vtermno, buf, count);
 871
 872	port = find_port_by_vtermno(vtermno);
 873	if (!port)
 874		return -EPIPE;
 875
 876	return send_buf(port, (void *)buf, count, false);
 
 877}
 878
 879/*
 880 * get_chars() is the callback from the hvc_console infrastructure
 881 * when an interrupt is received.
 882 *
 883 * We call out to fill_readbuf that gets us the required data from the
 884 * buffers that are queued up.
 885 */
 886static int get_chars(u32 vtermno, char *buf, int count)
 887{
 888	struct port *port;
 889
 890	/* If we've not set up the port yet, we have no input to give. */
 891	if (unlikely(early_put_chars))
 892		return 0;
 893
 894	port = find_port_by_vtermno(vtermno);
 895	if (!port)
 896		return -EPIPE;
 897
 898	/* If we don't have an input queue yet, we can't get input. */
 899	BUG_ON(!port->in_vq);
 900
 901	return fill_readbuf(port, buf, count, false);
 902}
 903
 904static void resize_console(struct port *port)
 905{
 906	struct virtio_device *vdev;
 907
 908	/* The port could have been hot-unplugged */
 909	if (!port || !is_console_port(port))
 910		return;
 911
 912	vdev = port->portdev->vdev;
 913	if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
 
 
 
 914		hvc_resize(port->cons.hvc, port->cons.ws);
 915}
 916
 917/* We set the configuration at this point, since we now have a tty */
 918static int notifier_add_vio(struct hvc_struct *hp, int data)
 919{
 920	struct port *port;
 921
 922	port = find_port_by_vtermno(hp->vtermno);
 923	if (!port)
 924		return -EINVAL;
 925
 926	hp->irq_requested = 1;
 927	resize_console(port);
 928
 929	return 0;
 930}
 931
 932static void notifier_del_vio(struct hvc_struct *hp, int data)
 933{
 934	hp->irq_requested = 0;
 935}
 936
 937/* The operations for console ports. */
 938static const struct hv_ops hv_ops = {
 939	.get_chars = get_chars,
 940	.put_chars = put_chars,
 941	.notifier_add = notifier_add_vio,
 942	.notifier_del = notifier_del_vio,
 943	.notifier_hangup = notifier_del_vio,
 944};
 945
 946/*
 947 * Console drivers are initialized very early so boot messages can go
 948 * out, so we do things slightly differently from the generic virtio
 949 * initialization of the net and block drivers.
 950 *
 951 * At this stage, the console is output-only.  It's too early to set
 952 * up a virtqueue, so we let the drivers do some boutique early-output
 953 * thing.
 954 */
 955int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
 956{
 957	early_put_chars = put_chars;
 958	return hvc_instantiate(0, 0, &hv_ops);
 959}
 960
 961int init_port_console(struct port *port)
 962{
 963	int ret;
 964
 965	/*
 966	 * The Host's telling us this port is a console port.  Hook it
 967	 * up with an hvc console.
 968	 *
 969	 * To set up and manage our virtual console, we call
 970	 * hvc_alloc().
 971	 *
 972	 * The first argument of hvc_alloc() is the virtual console
 973	 * number.  The second argument is the parameter for the
 974	 * notification mechanism (like irq number).  We currently
 975	 * leave this as zero, virtqueues have implicit notifications.
 976	 *
 977	 * The third argument is a "struct hv_ops" containing the
 978	 * put_chars() get_chars(), notifier_add() and notifier_del()
 979	 * pointers.  The final argument is the output buffer size: we
 980	 * can do any size, so we put PAGE_SIZE here.
 981	 */
 982	port->cons.vtermno = pdrvdata.next_vtermno;
 983
 984	port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
 985	if (IS_ERR(port->cons.hvc)) {
 986		ret = PTR_ERR(port->cons.hvc);
 987		dev_err(port->dev,
 988			"error %d allocating hvc for port\n", ret);
 989		port->cons.hvc = NULL;
 990		return ret;
 991	}
 992	spin_lock_irq(&pdrvdata_lock);
 993	pdrvdata.next_vtermno++;
 994	list_add_tail(&port->cons.list, &pdrvdata.consoles);
 995	spin_unlock_irq(&pdrvdata_lock);
 996	port->guest_connected = true;
 997
 998	/*
 999	 * Start using the new console output if this is the first
1000	 * console to come up.
1001	 */
1002	if (early_put_chars)
1003		early_put_chars = NULL;
1004
1005	/* Notify host of port being opened */
1006	send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
1007
1008	return 0;
1009}
1010
1011static ssize_t show_port_name(struct device *dev,
1012			      struct device_attribute *attr, char *buffer)
1013{
1014	struct port *port;
1015
1016	port = dev_get_drvdata(dev);
1017
1018	return sprintf(buffer, "%s\n", port->name);
1019}
1020
1021static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
1022
1023static struct attribute *port_sysfs_entries[] = {
1024	&dev_attr_name.attr,
1025	NULL
1026};
1027
1028static struct attribute_group port_attribute_group = {
1029	.name = NULL,		/* put in device directory */
1030	.attrs = port_sysfs_entries,
1031};
1032
1033static int debugfs_open(struct inode *inode, struct file *filp)
1034{
1035	filp->private_data = inode->i_private;
1036	return 0;
1037}
1038
1039static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
1040			    size_t count, loff_t *offp)
1041{
1042	struct port *port;
1043	char *buf;
1044	ssize_t ret, out_offset, out_count;
1045
1046	out_count = 1024;
1047	buf = kmalloc(out_count, GFP_KERNEL);
1048	if (!buf)
1049		return -ENOMEM;
1050
1051	port = filp->private_data;
1052	out_offset = 0;
1053	out_offset += snprintf(buf + out_offset, out_count,
1054			       "name: %s\n", port->name ? port->name : "");
1055	out_offset += snprintf(buf + out_offset, out_count - out_offset,
1056			       "guest_connected: %d\n", port->guest_connected);
1057	out_offset += snprintf(buf + out_offset, out_count - out_offset,
1058			       "host_connected: %d\n", port->host_connected);
1059	out_offset += snprintf(buf + out_offset, out_count - out_offset,
1060			       "outvq_full: %d\n", port->outvq_full);
1061	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 
 
 
 
 
 
 
 
1062			       "is_console: %s\n",
1063			       is_console_port(port) ? "yes" : "no");
1064	out_offset += snprintf(buf + out_offset, out_count - out_offset,
1065			       "console_vtermno: %u\n", port->cons.vtermno);
1066
1067	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
1068	kfree(buf);
1069	return ret;
1070}
1071
1072static const struct file_operations port_debugfs_ops = {
1073	.owner = THIS_MODULE,
1074	.open  = debugfs_open,
1075	.read  = debugfs_read,
1076};
1077
1078static void set_console_size(struct port *port, u16 rows, u16 cols)
1079{
1080	if (!port || !is_console_port(port))
1081		return;
1082
1083	port->cons.ws.ws_row = rows;
1084	port->cons.ws.ws_col = cols;
1085}
1086
1087static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
1088{
1089	struct port_buffer *buf;
1090	unsigned int nr_added_bufs;
1091	int ret;
1092
1093	nr_added_bufs = 0;
1094	do {
1095		buf = alloc_buf(PAGE_SIZE);
1096		if (!buf)
1097			break;
1098
1099		spin_lock_irq(lock);
1100		ret = add_inbuf(vq, buf);
1101		if (ret < 0) {
1102			spin_unlock_irq(lock);
1103			free_buf(buf);
1104			break;
1105		}
1106		nr_added_bufs++;
1107		spin_unlock_irq(lock);
1108	} while (ret > 0);
1109
1110	return nr_added_bufs;
1111}
1112
1113static void send_sigio_to_port(struct port *port)
1114{
1115	if (port->async_queue && port->guest_connected)
1116		kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
1117}
1118
1119static int add_port(struct ports_device *portdev, u32 id)
1120{
1121	char debugfs_name[16];
1122	struct port *port;
1123	struct port_buffer *buf;
1124	dev_t devt;
1125	unsigned int nr_added_bufs;
1126	int err;
1127
1128	port = kmalloc(sizeof(*port), GFP_KERNEL);
1129	if (!port) {
1130		err = -ENOMEM;
1131		goto fail;
1132	}
1133	kref_init(&port->kref);
1134
1135	port->portdev = portdev;
1136	port->id = id;
1137
1138	port->name = NULL;
1139	port->inbuf = NULL;
1140	port->cons.hvc = NULL;
1141	port->async_queue = NULL;
1142
1143	port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
1144
1145	port->host_connected = port->guest_connected = false;
 
1146
1147	port->outvq_full = false;
1148
1149	port->in_vq = portdev->in_vqs[port->id];
1150	port->out_vq = portdev->out_vqs[port->id];
1151
1152	port->cdev = cdev_alloc();
1153	if (!port->cdev) {
1154		dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
1155		err = -ENOMEM;
1156		goto free_port;
1157	}
1158	port->cdev->ops = &port_fops;
1159
1160	devt = MKDEV(portdev->chr_major, id);
1161	err = cdev_add(port->cdev, devt, 1);
1162	if (err < 0) {
1163		dev_err(&port->portdev->vdev->dev,
1164			"Error %d adding cdev for port %u\n", err, id);
1165		goto free_cdev;
1166	}
1167	port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
1168				  devt, port, "vport%up%u",
1169				  port->portdev->drv_index, id);
1170	if (IS_ERR(port->dev)) {
1171		err = PTR_ERR(port->dev);
1172		dev_err(&port->portdev->vdev->dev,
1173			"Error %d creating device for port %u\n",
1174			err, id);
1175		goto free_cdev;
1176	}
1177
1178	spin_lock_init(&port->inbuf_lock);
1179	spin_lock_init(&port->outvq_lock);
1180	init_waitqueue_head(&port->waitqueue);
1181
1182	/* Fill the in_vq with buffers so the host can send us data. */
1183	nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
1184	if (!nr_added_bufs) {
1185		dev_err(port->dev, "Error allocating inbufs\n");
1186		err = -ENOMEM;
1187		goto free_device;
1188	}
1189
1190	/*
1191	 * If we're not using multiport support, this has to be a console port
1192	 */
1193	if (!use_multiport(port->portdev)) {
 
 
 
 
 
 
 
 
1194		err = init_port_console(port);
1195		if (err)
1196			goto free_inbufs;
1197	}
1198
1199	spin_lock_irq(&portdev->ports_lock);
1200	list_add_tail(&port->list, &port->portdev->ports);
1201	spin_unlock_irq(&portdev->ports_lock);
1202
1203	/*
1204	 * Tell the Host we're set so that it can send us various
1205	 * configuration parameters for this port (eg, port name,
1206	 * caching, whether this is a console port, etc.)
1207	 */
1208	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1209
1210	if (pdrvdata.debugfs_dir) {
1211		/*
1212		 * Finally, create the debugfs file that we can use to
1213		 * inspect a port's state at any time
1214		 */
1215		sprintf(debugfs_name, "vport%up%u",
1216			port->portdev->drv_index, id);
1217		port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
1218							 pdrvdata.debugfs_dir,
1219							 port,
1220							 &port_debugfs_ops);
1221	}
1222	return 0;
1223
1224free_inbufs:
1225	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1226		free_buf(buf);
1227free_device:
1228	device_destroy(pdrvdata.class, port->dev->devt);
1229free_cdev:
1230	cdev_del(port->cdev);
1231free_port:
1232	kfree(port);
1233fail:
1234	/* The host might want to notify management sw about port add failure */
1235	__send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
1236	return err;
1237}
1238
1239/* No users remain, remove all port-specific data. */
1240static void remove_port(struct kref *kref)
1241{
1242	struct port *port;
1243
1244	port = container_of(kref, struct port, kref);
1245
1246	sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
1247	device_destroy(pdrvdata.class, port->dev->devt);
1248	cdev_del(port->cdev);
1249
1250	kfree(port->name);
 
 
1251
1252	debugfs_remove(port->debugfs_file);
 
 
1253
1254	kfree(port);
 
 
 
 
 
 
 
 
 
 
 
1255}
1256
1257/*
1258 * Port got unplugged.  Remove port from portdev's list and drop the
1259 * kref reference.  If no userspace has this port opened, it will
1260 * result in immediate removal the port.
1261 */
1262static void unplug_port(struct port *port)
1263{
1264	struct port_buffer *buf;
1265
1266	spin_lock_irq(&port->portdev->ports_lock);
1267	list_del(&port->list);
1268	spin_unlock_irq(&port->portdev->ports_lock);
1269
 
1270	if (port->guest_connected) {
 
 
 
 
1271		port->guest_connected = false;
1272		port->host_connected = false;
1273		wake_up_interruptible(&port->waitqueue);
1274
1275		/* Let the app know the port is going down. */
1276		send_sigio_to_port(port);
1277	}
 
1278
1279	if (is_console_port(port)) {
1280		spin_lock_irq(&pdrvdata_lock);
1281		list_del(&port->cons.list);
1282		spin_unlock_irq(&pdrvdata_lock);
1283		hvc_remove(port->cons.hvc);
1284	}
1285
1286	/* Remove unused data this port might have received. */
1287	discard_port_data(port);
1288
1289	reclaim_consumed_buffers(port);
1290
1291	/* Remove buffers we queued up for the Host to send us data in. */
1292	while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
1293		free_buf(buf);
1294
1295	/*
1296	 * We should just assume the device itself has gone off --
1297	 * else a close on an open port later will try to send out a
1298	 * control message.
1299	 */
1300	port->portdev = NULL;
1301
 
 
 
 
 
 
 
1302	/*
1303	 * Locks around here are not necessary - a port can't be
1304	 * opened after we removed the port struct from ports_list
1305	 * above.
1306	 */
1307	kref_put(&port->kref, remove_port);
1308}
1309
1310/* Any private messages that the Host and Guest want to share */
1311static void handle_control_message(struct ports_device *portdev,
1312				   struct port_buffer *buf)
1313{
1314	struct virtio_console_control *cpkt;
1315	struct port *port;
1316	size_t name_size;
1317	int err;
1318
1319	cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
1320
1321	port = find_port_by_id(portdev, cpkt->id);
1322	if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
1323		/* No valid header at start of buffer.  Drop it. */
1324		dev_dbg(&portdev->vdev->dev,
1325			"Invalid index %u in control packet\n", cpkt->id);
1326		return;
1327	}
1328
1329	switch (cpkt->event) {
1330	case VIRTIO_CONSOLE_PORT_ADD:
1331		if (port) {
1332			dev_dbg(&portdev->vdev->dev,
1333				"Port %u already added\n", port->id);
1334			send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
1335			break;
1336		}
1337		if (cpkt->id >= portdev->config.max_nr_ports) {
1338			dev_warn(&portdev->vdev->dev,
1339				"Request for adding port with out-of-bound id %u, max. supported id: %u\n",
1340				cpkt->id, portdev->config.max_nr_ports - 1);
1341			break;
1342		}
1343		add_port(portdev, cpkt->id);
1344		break;
1345	case VIRTIO_CONSOLE_PORT_REMOVE:
1346		unplug_port(port);
1347		break;
1348	case VIRTIO_CONSOLE_CONSOLE_PORT:
1349		if (!cpkt->value)
1350			break;
1351		if (is_console_port(port))
1352			break;
1353
1354		init_port_console(port);
 
1355		/*
1356		 * Could remove the port here in case init fails - but
1357		 * have to notify the host first.
1358		 */
1359		break;
1360	case VIRTIO_CONSOLE_RESIZE: {
1361		struct {
1362			__u16 rows;
1363			__u16 cols;
1364		} size;
1365
1366		if (!is_console_port(port))
1367			break;
1368
1369		memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
1370		       sizeof(size));
1371		set_console_size(port, size.rows, size.cols);
1372
1373		port->cons.hvc->irq_requested = 1;
1374		resize_console(port);
1375		break;
1376	}
1377	case VIRTIO_CONSOLE_PORT_OPEN:
1378		port->host_connected = cpkt->value;
1379		wake_up_interruptible(&port->waitqueue);
1380		/*
1381		 * If the host port got closed and the host had any
1382		 * unconsumed buffers, we'll be able to reclaim them
1383		 * now.
1384		 */
1385		spin_lock_irq(&port->outvq_lock);
1386		reclaim_consumed_buffers(port);
1387		spin_unlock_irq(&port->outvq_lock);
1388
1389		/*
1390		 * If the guest is connected, it'll be interested in
1391		 * knowing the host connection state changed.
1392		 */
 
1393		send_sigio_to_port(port);
 
1394		break;
1395	case VIRTIO_CONSOLE_PORT_NAME:
1396		/*
 
 
 
 
 
 
 
1397		 * Skip the size of the header and the cpkt to get the size
1398		 * of the name that was sent
1399		 */
1400		name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
1401
1402		port->name = kmalloc(name_size, GFP_KERNEL);
1403		if (!port->name) {
1404			dev_err(port->dev,
1405				"Not enough space to store port name\n");
1406			break;
1407		}
1408		strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
1409			name_size - 1);
1410		port->name[name_size - 1] = 0;
1411
1412		/*
1413		 * Since we only have one sysfs attribute, 'name',
1414		 * create it only if we have a name for the port.
1415		 */
1416		err = sysfs_create_group(&port->dev->kobj,
1417					 &port_attribute_group);
1418		if (err) {
1419			dev_err(port->dev,
1420				"Error %d creating sysfs device attributes\n",
1421				err);
1422		} else {
1423			/*
1424			 * Generate a udev event so that appropriate
1425			 * symlinks can be created based on udev
1426			 * rules.
1427			 */
1428			kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
1429		}
1430		break;
1431	}
1432}
1433
1434static void control_work_handler(struct work_struct *work)
1435{
1436	struct ports_device *portdev;
1437	struct virtqueue *vq;
1438	struct port_buffer *buf;
1439	unsigned int len;
1440
1441	portdev = container_of(work, struct ports_device, control_work);
1442	vq = portdev->c_ivq;
1443
1444	spin_lock(&portdev->cvq_lock);
1445	while ((buf = virtqueue_get_buf(vq, &len))) {
1446		spin_unlock(&portdev->cvq_lock);
1447
1448		buf->len = len;
1449		buf->offset = 0;
1450
1451		handle_control_message(portdev, buf);
1452
1453		spin_lock(&portdev->cvq_lock);
1454		if (add_inbuf(portdev->c_ivq, buf) < 0) {
1455			dev_warn(&portdev->vdev->dev,
1456				 "Error adding buffer to queue\n");
1457			free_buf(buf);
1458		}
1459	}
1460	spin_unlock(&portdev->cvq_lock);
1461}
1462
1463static void out_intr(struct virtqueue *vq)
1464{
1465	struct port *port;
1466
1467	port = find_port_by_vq(vq->vdev->priv, vq);
1468	if (!port)
1469		return;
1470
1471	wake_up_interruptible(&port->waitqueue);
1472}
1473
1474static void in_intr(struct virtqueue *vq)
1475{
1476	struct port *port;
1477	unsigned long flags;
1478
1479	port = find_port_by_vq(vq->vdev->priv, vq);
1480	if (!port)
1481		return;
1482
1483	spin_lock_irqsave(&port->inbuf_lock, flags);
1484	if (!port->inbuf)
1485		port->inbuf = get_inbuf(port);
1486
1487	/*
1488	 * Don't queue up data when port is closed.  This condition
 
 
1489	 * can be reached when a console port is not yet connected (no
1490	 * tty is spawned) and the host sends out data to console
1491	 * ports.  For generic serial ports, the host won't
1492	 * (shouldn't) send data till the guest is connected.
 
 
 
 
 
 
 
1493	 */
1494	if (!port->guest_connected)
 
1495		discard_port_data(port);
1496
 
 
 
1497	spin_unlock_irqrestore(&port->inbuf_lock, flags);
1498
1499	wake_up_interruptible(&port->waitqueue);
1500
1501	/* Send a SIGIO indicating new data in case the process asked for it */
1502	send_sigio_to_port(port);
1503
1504	if (is_console_port(port) && hvc_poll(port->cons.hvc))
1505		hvc_kick();
1506}
1507
1508static void control_intr(struct virtqueue *vq)
1509{
1510	struct ports_device *portdev;
1511
1512	portdev = vq->vdev->priv;
1513	schedule_work(&portdev->control_work);
1514}
1515
1516static void config_intr(struct virtio_device *vdev)
1517{
1518	struct ports_device *portdev;
1519
1520	portdev = vdev->priv;
1521
1522	if (!use_multiport(portdev)) {
1523		struct port *port;
1524		u16 rows, cols;
1525
1526		vdev->config->get(vdev,
1527				  offsetof(struct virtio_console_config, cols),
1528				  &cols, sizeof(u16));
1529		vdev->config->get(vdev,
1530				  offsetof(struct virtio_console_config, rows),
1531				  &rows, sizeof(u16));
1532
1533		port = find_port_by_id(portdev, 0);
1534		set_console_size(port, rows, cols);
1535
1536		/*
1537		 * We'll use this way of resizing only for legacy
1538		 * support.  For newer userspace
1539		 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
1540		 * to indicate console size changes so that it can be
1541		 * done per-port.
1542		 */
1543		resize_console(port);
1544	}
1545}
1546
1547static int init_vqs(struct ports_device *portdev)
1548{
1549	vq_callback_t **io_callbacks;
1550	char **io_names;
1551	struct virtqueue **vqs;
1552	u32 i, j, nr_ports, nr_queues;
1553	int err;
1554
1555	nr_ports = portdev->config.max_nr_ports;
1556	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
1557
1558	vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
1559	io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
1560	io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
1561	portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1562				  GFP_KERNEL);
1563	portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
1564				   GFP_KERNEL);
1565	if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
1566			!portdev->out_vqs) {
1567		err = -ENOMEM;
1568		goto free;
1569	}
1570
1571	/*
1572	 * For backward compat (newer host but older guest), the host
1573	 * spawns a console port first and also inits the vqs for port
1574	 * 0 before others.
1575	 */
1576	j = 0;
1577	io_callbacks[j] = in_intr;
1578	io_callbacks[j + 1] = out_intr;
1579	io_names[j] = "input";
1580	io_names[j + 1] = "output";
1581	j += 2;
1582
1583	if (use_multiport(portdev)) {
1584		io_callbacks[j] = control_intr;
1585		io_callbacks[j + 1] = NULL;
1586		io_names[j] = "control-i";
1587		io_names[j + 1] = "control-o";
1588
1589		for (i = 1; i < nr_ports; i++) {
1590			j += 2;
1591			io_callbacks[j] = in_intr;
1592			io_callbacks[j + 1] = out_intr;
1593			io_names[j] = "input";
1594			io_names[j + 1] = "output";
1595		}
1596	}
1597	/* Find the queues. */
1598	err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
1599					      io_callbacks,
1600					      (const char **)io_names);
1601	if (err)
1602		goto free;
1603
1604	j = 0;
1605	portdev->in_vqs[0] = vqs[0];
1606	portdev->out_vqs[0] = vqs[1];
1607	j += 2;
1608	if (use_multiport(portdev)) {
1609		portdev->c_ivq = vqs[j];
1610		portdev->c_ovq = vqs[j + 1];
1611
1612		for (i = 1; i < nr_ports; i++) {
1613			j += 2;
1614			portdev->in_vqs[i] = vqs[j];
1615			portdev->out_vqs[i] = vqs[j + 1];
1616		}
1617	}
1618	kfree(io_names);
1619	kfree(io_callbacks);
1620	kfree(vqs);
1621
1622	return 0;
1623
1624free:
1625	kfree(portdev->out_vqs);
1626	kfree(portdev->in_vqs);
1627	kfree(io_names);
1628	kfree(io_callbacks);
1629	kfree(vqs);
1630
1631	return err;
1632}
1633
1634static const struct file_operations portdev_fops = {
1635	.owner = THIS_MODULE,
1636};
1637
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1638/*
1639 * Once we're further in boot, we get probed like any other virtio
1640 * device.
1641 *
1642 * If the host also supports multiple console ports, we check the
1643 * config space to see how many ports the host has spawned.  We
1644 * initialize each port found.
1645 */
1646static int __devinit virtcons_probe(struct virtio_device *vdev)
1647{
1648	struct ports_device *portdev;
1649	int err;
1650	bool multiport;
 
 
 
 
1651
1652	portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
1653	if (!portdev) {
1654		err = -ENOMEM;
1655		goto fail;
1656	}
1657
1658	/* Attach this portdev to this virtio_device, and vice-versa. */
1659	portdev->vdev = vdev;
1660	vdev->priv = portdev;
1661
1662	spin_lock_irq(&pdrvdata_lock);
1663	portdev->drv_index = pdrvdata.index++;
1664	spin_unlock_irq(&pdrvdata_lock);
1665
1666	portdev->chr_major = register_chrdev(0, "virtio-portsdev",
1667					     &portdev_fops);
1668	if (portdev->chr_major < 0) {
1669		dev_err(&vdev->dev,
1670			"Error %d registering chrdev for device %u\n",
1671			portdev->chr_major, portdev->drv_index);
1672		err = portdev->chr_major;
1673		goto free;
1674	}
1675
1676	multiport = false;
1677	portdev->config.max_nr_ports = 1;
1678	if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
 
 
 
 
 
1679		multiport = true;
1680		vdev->config->get(vdev, offsetof(struct virtio_console_config,
1681						 max_nr_ports),
1682				  &portdev->config.max_nr_ports,
1683				  sizeof(portdev->config.max_nr_ports));
1684	}
1685
1686	err = init_vqs(portdev);
1687	if (err < 0) {
1688		dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
1689		goto free_chrdev;
1690	}
1691
1692	spin_lock_init(&portdev->ports_lock);
1693	INIT_LIST_HEAD(&portdev->ports);
1694
1695	if (multiport) {
1696		unsigned int nr_added_bufs;
1697
1698		spin_lock_init(&portdev->cvq_lock);
 
1699		INIT_WORK(&portdev->control_work, &control_work_handler);
1700
1701		nr_added_bufs = fill_queue(portdev->c_ivq, &portdev->cvq_lock);
 
1702		if (!nr_added_bufs) {
1703			dev_err(&vdev->dev,
1704				"Error allocating buffers for control queue\n");
1705			err = -ENOMEM;
1706			goto free_vqs;
1707		}
1708	} else {
1709		/*
1710		 * For backward compatibility: Create a console port
1711		 * if we're running on older host.
1712		 */
1713		add_port(portdev, 0);
1714	}
1715
1716	spin_lock_irq(&pdrvdata_lock);
1717	list_add_tail(&portdev->list, &pdrvdata.portdevs);
1718	spin_unlock_irq(&pdrvdata_lock);
1719
1720	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1721			   VIRTIO_CONSOLE_DEVICE_READY, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
1722	return 0;
1723
1724free_vqs:
1725	/* The host might want to notify mgmt sw about device add failure */
1726	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
1727			   VIRTIO_CONSOLE_DEVICE_READY, 0);
1728	vdev->config->del_vqs(vdev);
1729	kfree(portdev->in_vqs);
1730	kfree(portdev->out_vqs);
1731free_chrdev:
1732	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1733free:
1734	kfree(portdev);
1735fail:
1736	return err;
1737}
1738
1739static void virtcons_remove(struct virtio_device *vdev)
1740{
1741	struct ports_device *portdev;
1742	struct port *port, *port2;
1743
1744	portdev = vdev->priv;
1745
1746	spin_lock_irq(&pdrvdata_lock);
1747	list_del(&portdev->list);
1748	spin_unlock_irq(&pdrvdata_lock);
1749
1750	/* Disable interrupts for vqs */
1751	vdev->config->reset(vdev);
1752	/* Finish up work that's lined up */
1753	cancel_work_sync(&portdev->control_work);
 
1754
1755	list_for_each_entry_safe(port, port2, &portdev->ports, list)
1756		unplug_port(port);
1757
1758	unregister_chrdev(portdev->chr_major, "virtio-portsdev");
1759
1760	/*
1761	 * When yanking out a device, we immediately lose the
1762	 * (device-side) queues.  So there's no point in keeping the
1763	 * guest side around till we drop our final reference.  This
1764	 * also means that any ports which are in an open state will
1765	 * have to just stop using the port, as the vqs are going
1766	 * away.
1767	 */
1768	if (use_multiport(portdev)) {
1769		struct port_buffer *buf;
1770		unsigned int len;
1771
1772		while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
1773			free_buf(buf);
1774
1775		while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
1776			free_buf(buf);
1777	}
1778
1779	vdev->config->del_vqs(vdev);
1780	kfree(portdev->in_vqs);
1781	kfree(portdev->out_vqs);
1782
1783	kfree(portdev);
1784}
1785
1786static struct virtio_device_id id_table[] = {
1787	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
1788	{ 0 },
1789};
1790
1791static unsigned int features[] = {
1792	VIRTIO_CONSOLE_F_SIZE,
1793	VIRTIO_CONSOLE_F_MULTIPORT,
1794};
1795
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1796static struct virtio_driver virtio_console = {
1797	.feature_table = features,
1798	.feature_table_size = ARRAY_SIZE(features),
1799	.driver.name =	KBUILD_MODNAME,
1800	.driver.owner =	THIS_MODULE,
1801	.id_table =	id_table,
1802	.probe =	virtcons_probe,
1803	.remove =	virtcons_remove,
1804	.config_changed = config_intr,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1805};
1806
1807static int __init init(void)
1808{
1809	int err;
1810
1811	pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
1812	if (IS_ERR(pdrvdata.class)) {
1813		err = PTR_ERR(pdrvdata.class);
1814		pr_err("Error %d creating virtio-ports class\n", err);
1815		return err;
1816	}
1817
1818	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
1819	if (!pdrvdata.debugfs_dir) {
1820		pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
1821			   PTR_ERR(pdrvdata.debugfs_dir));
1822	}
1823	INIT_LIST_HEAD(&pdrvdata.consoles);
1824	INIT_LIST_HEAD(&pdrvdata.portdevs);
1825
1826	return register_virtio_driver(&virtio_console);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1827}
1828
1829static void __exit fini(void)
1830{
 
 
1831	unregister_virtio_driver(&virtio_console);
 
1832
1833	class_destroy(pdrvdata.class);
1834	if (pdrvdata.debugfs_dir)
1835		debugfs_remove_recursive(pdrvdata.debugfs_dir);
1836}
1837module_init(init);
1838module_exit(fini);
1839
1840MODULE_DEVICE_TABLE(virtio, id_table);
1841MODULE_DESCRIPTION("Virtio console driver");
1842MODULE_LICENSE("GPL");