[net-next-2.6.git] / drivers / char / virtio_console.c

/*
 * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/err.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/virtio.h>
#include <linux/virtio_console.h>
#include "hvc_console.h"

/*
 * This is a global struct for storing common data for all the devices
 * this driver handles.
 *
 * Mainly, it has a linked list for all the consoles in one place so
 * that callbacks from hvc for get_chars(), put_chars() work properly
 * across multiple devices and multiple ports per device.
 */
struct ports_driver_data {
	/*
	 * This is used to keep track of the number of hvc consoles
	 * spawned by this driver.  This number is given as the first
	 * argument to hvc_alloc().  To correctly map an initial
	 * console spawned via hvc_instantiate to the console being
	 * hooked up via hvc_alloc, we need to pass the same vtermno.
	 *
	 * We also just assume the first console being initialised was
	 * the first one that got used as the initial console.
	 */
	unsigned int next_vtermno;

	/* All the console devices handled by this driver */
	struct list_head consoles;
};
static struct ports_driver_data pdrvdata;

DEFINE_SPINLOCK(pdrvdata_lock);

struct port_buffer {
	char *buf;

	/* size of the buffer in *buf above */
	size_t size;

	/* used length of the buffer */
	size_t len;
	/* offset in the buf from which to consume data */
	size_t offset;
};

struct port {
	struct virtqueue *in_vq, *out_vq;
	struct virtio_device *vdev;

	/* The current buffer from which data has to be fed to readers */
	struct port_buffer *inbuf;

	/* For console ports, hvc != NULL and these are valid. */
	/* The hvc device */
	struct hvc_struct *hvc;

	/* We'll place all consoles in a list in the pdrvdata struct */
	struct list_head list;

	/* Our vterm number. */
	u32 vtermno;
};

/* This is the very early arch-specified put chars function. */
static int (*early_put_chars)(u32, const char *, int);

static struct port *find_port_by_vtermno(u32 vtermno)
{
	struct port *port;
	unsigned long flags;

	spin_lock_irqsave(&pdrvdata_lock, flags);
	list_for_each_entry(port, &pdrvdata.consoles, list) {
		if (port->vtermno == vtermno)
			goto out;
	}
	port = NULL;
out:
	spin_unlock_irqrestore(&pdrvdata_lock, flags);
	return port;
}

static void free_buf(struct port_buffer *buf)
{
	kfree(buf->buf);
	kfree(buf);
}

static struct port_buffer *alloc_buf(size_t buf_size)
{
	struct port_buffer *buf;

	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
	if (!buf)
		goto fail;
	buf->buf = kzalloc(buf_size, GFP_KERNEL);
	if (!buf->buf)
		goto free_buf;
	buf->len = 0;
	buf->offset = 0;
	buf->size = buf_size;
	return buf;

free_buf:
	kfree(buf);
fail:
	return NULL;
}

/* Callers should take appropriate locks */
static void *get_inbuf(struct port *port)
{
	struct port_buffer *buf;
	struct virtqueue *vq;
	unsigned int len;

	vq = port->in_vq;
	buf = vq->vq_ops->get_buf(vq, &len);
	if (buf) {
		buf->len = len;
		buf->offset = 0;
	}
	return buf;
}

/*
 * Create a scatter-gather list representing our input buffer and put
 * it in the queue.
 *
 * Callers should take appropriate locks.
 */
static void add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
{
	struct scatterlist sg[1];
	sg_init_one(sg, buf->buf, buf->size);

	if (vq->vq_ops->add_buf(vq, sg, 0, 1, buf) < 0)
		BUG();
	vq->vq_ops->kick(vq);
}

/*
 * The put_chars() callback is pretty straightforward.
 *
 * We turn the characters into a scatter-gather list, add it to the
 * output queue and then kick the Host.  Then we sit here waiting for
 * it to finish: inefficient in theory, but in practice
 * implementations will do it immediately (lguest's Launcher does).
 */
static int put_chars(u32 vtermno, const char *buf, int count)
{
	struct scatterlist sg[1];
	struct port *port;
	unsigned int len;

	port = find_port_by_vtermno(vtermno);
	if (!port)
		return 0;

	if (unlikely(early_put_chars))
		return early_put_chars(vtermno, buf, count);

	/* This is a convenient routine to initialize a single-elem sg list */
	sg_init_one(sg, buf, count);

	/* This shouldn't fail: if it does, we lose chars. */
	if (port->out_vq->vq_ops->add_buf(port->out_vq, sg, 1, 0, port) >= 0) {
		/* Tell Host to go! */
		port->out_vq->vq_ops->kick(port->out_vq);
		while (!port->out_vq->vq_ops->get_buf(port->out_vq, &len))
			cpu_relax();
	}

	/* We're expected to return the amount of data we wrote: all of it. */
	return count;
}

/*
 * get_chars() is the callback from the hvc_console infrastructure
 * when an interrupt is received.
 *
 * Most of the code deals with the fact that the hvc_console()
 * infrastructure only asks us for 16 bytes at a time.  We keep
 * in_offset and in_used fields for partially-filled buffers.
 */
static int get_chars(u32 vtermno, char *buf, int count)
{
	struct port *port;


	port = find_port_by_vtermno(vtermno);
	if (!port)
		return 0;

	/* If we don't have an input queue yet, we can't get input. */
	BUG_ON(!port->in_vq);

	/* No more in buffer?  See if they've (re)used it. */
	if (port->inbuf->offset == port->inbuf->len) {
		if (!get_inbuf(port))
			return 0;
	}

	/* You want more than we have to give?  Well, try wanting less! */
	if (port->inbuf->offset + count > port->inbuf->len)
		count = port->inbuf->len - port->inbuf->offset;

	/* Copy across to their buffer and increment offset. */
	memcpy(buf, port->inbuf->buf + port->inbuf->offset, count);
	port->inbuf->offset += count;

	/* Finished?  Re-register buffer so Host will use it again. */
	if (port->inbuf->offset == port->inbuf->len)
		add_inbuf(port->in_vq, port->inbuf);

	return count;
}

/*
 * virtio console configuration. This supports:
 * - console resize
 */
static void virtcons_apply_config(struct virtio_device *dev)
{
	struct port *port = dev->priv;
	struct winsize ws;

	if (virtio_has_feature(dev, VIRTIO_CONSOLE_F_SIZE)) {
		dev->config->get(dev,
				 offsetof(struct virtio_console_config, cols),
				 &ws.ws_col, sizeof(u16));
		dev->config->get(dev,
				 offsetof(struct virtio_console_config, rows),
				 &ws.ws_row, sizeof(u16));
		hvc_resize(port->hvc, ws);
	}
}

/* We set the configuration at this point, since we now have a tty */
static int notifier_add_vio(struct hvc_struct *hp, int data)
{
	struct port *port;

	port = find_port_by_vtermno(hp->vtermno);
	if (!port)
		return -EINVAL;

	hp->irq_requested = 1;
	virtcons_apply_config(port->vdev);

	return 0;
}

static void notifier_del_vio(struct hvc_struct *hp, int data)
{
	hp->irq_requested = 0;
}

static void hvc_handle_input(struct virtqueue *vq)
{
	struct port *port = vq->vdev->priv;

	if (hvc_poll(port->hvc))
		hvc_kick();
}

/* The operations for the console. */
static const struct hv_ops hv_ops = {
	.get_chars = get_chars,
	.put_chars = put_chars,
	.notifier_add = notifier_add_vio,
	.notifier_del = notifier_del_vio,
	.notifier_hangup = notifier_del_vio,
};

/*
 * Console drivers are initialized very early so boot messages can go
 * out, so we do things slightly differently from the generic virtio
 * initialization of the net and block drivers.
 *
 * At this stage, the console is output-only.  It's too early to set
 * up a virtqueue, so we let the drivers do some boutique early-output
 * thing.
 */
int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
{
	early_put_chars = put_chars;
	return hvc_instantiate(0, 0, &hv_ops);
}

static struct port *__devinit add_port(u32 vtermno)
{
	struct port *port;

	port = kmalloc(sizeof(*port), GFP_KERNEL);
	if (!port)
		return NULL;

	port->inbuf = alloc_buf(PAGE_SIZE);
	if (!port->inbuf) {
		kfree(port);
		return NULL;
	}
	port->hvc = NULL;
	port->vtermno = vtermno;
	return port;
}

static void free_port(struct port *port)
{
	free_buf(port->inbuf);
	kfree(port);
}

/*
 * Once we're further in boot, we get probed like any other virtio
 * device.  At this stage we set up the output virtqueue.
 *
 * To set up and manage our virtual console, we call hvc_alloc().
 * Since we never remove the console device we never need this pointer
 * again.
 *
 * Finally we put our input buffer in the input queue, ready to
 * receive.
 */
static int __devinit virtcons_probe(struct virtio_device *vdev)
{
	vq_callback_t *callbacks[] = { hvc_handle_input, NULL};
	const char *names[] = { "input", "output" };
	struct virtqueue *vqs[2];
	struct port *port;
	int err;

	port = add_port(pdrvdata.next_vtermno);
	if (!port) {
		err = -ENOMEM;
		goto fail;
	}

	/* Attach this port to this virtio_device, and vice-versa. */
	port->vdev = vdev;
	vdev->priv = port;

	/* Find the queues. */
	err = vdev->config->find_vqs(vdev, 2, vqs, callbacks, names);
	if (err)
		goto free;

	port->in_vq = vqs[0];
	port->out_vq = vqs[1];

	/*
	 * The first argument of hvc_alloc() is the virtual console
	 * number.  The second argument is the parameter for the
	 * notification mechanism (like irq number).  We currently
	 * leave this as zero, virtqueues have implicit notifications.
	 *
	 * The third argument is a "struct hv_ops" containing the
	 * put_chars(), get_chars(), notifier_add() and notifier_del()
	 * pointers.  The final argument is the output buffer size: we
	 * can do any size, so we put PAGE_SIZE here.
	 */
	port->hvc = hvc_alloc(port->vtermno, 0, &hv_ops, PAGE_SIZE);
	if (IS_ERR(port->hvc)) {
		err = PTR_ERR(port->hvc);
		goto free_vqs;
	}

	/* Add to vtermno list. */
	spin_lock_irq(&pdrvdata_lock);
	pdrvdata.next_vtermno++;
	list_add(&port->list, &pdrvdata.consoles);
	spin_unlock_irq(&pdrvdata_lock);

	/* Register the input buffer the first time. */
	add_inbuf(port->in_vq, port->inbuf);

	/* Start using the new console output. */
	early_put_chars = NULL;
	return 0;

free_vqs:
	vdev->config->del_vqs(vdev);
free:
	free_port(port);
fail:
	return err;
}

static struct virtio_device_id id_table[] = {
	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
	{ 0 },
};

static unsigned int features[] = {
	VIRTIO_CONSOLE_F_SIZE,
};

static struct virtio_driver virtio_console = {
	.feature_table = features,
	.feature_table_size = ARRAY_SIZE(features),
	.driver.name =	KBUILD_MODNAME,
	.driver.owner =	THIS_MODULE,
	.id_table =	id_table,
	.probe =	virtcons_probe,
	.config_changed = virtcons_apply_config,
};

static int __init init(void)
{
	INIT_LIST_HEAD(&pdrvdata.consoles);

	return register_virtio_driver(&virtio_console);
}
module_init(init);

MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio console driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
a23ea924 RR	1	/*
a23ea924 RR	2	* Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
31610434 RR	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write to the Free Software
	16	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	17	*/
	18	#include <linux/err.h>
	19	#include <linux/init.h>
38edf58d AS	20	#include <linux/list.h>
38edf58d AS	21	#include <linux/spinlock.h>
31610434 RR	22	#include <linux/virtio.h>
	23	#include <linux/virtio_console.h>
	24	#include "hvc_console.h"
	25
38edf58d AS	26	/*
	27	* This is a global struct for storing common data for all the devices
	28	* this driver handles.
	29	*
	30	* Mainly, it has a linked list for all the consoles in one place so
	31	* that callbacks from hvc for get_chars(), put_chars() work properly
	32	* across multiple devices and multiple ports per device.
	33	*/
	34	struct ports_driver_data {
d8a02bd5 RR	35	/*
	36	* This is used to keep track of the number of hvc consoles
	37	* spawned by this driver. This number is given as the first
	38	* argument to hvc_alloc(). To correctly map an initial
	39	* console spawned via hvc_instantiate to the console being
	40	* hooked up via hvc_alloc, we need to pass the same vtermno.
	41	*
	42	* We also just assume the first console being initialised was
	43	* the first one that got used as the initial console.
	44	*/
	45	unsigned int next_vtermno;
	46
38edf58d AS	47	/* All the console devices handled by this driver */
	48	struct list_head consoles;
	49	};
	50	static struct ports_driver_data pdrvdata;
	51
	52	DEFINE_SPINLOCK(pdrvdata_lock);
	53
fdb9a054 AS	54	struct port_buffer {
	55	char *buf;
	56
	57	/* size of the buffer in buf above /
	58	size_t size;
	59
	60	/* used length of the buffer */
	61	size_t len;
	62	/* offset in the buf from which to consume data */
	63	size_t offset;
	64	};
	65
21206ede RR	66	struct port {
	67	struct virtqueue in_vq, out_vq;
	68	struct virtio_device *vdev;
fdb9a054 AS	69
	70	/* The current buffer from which data has to be fed to readers */
	71	struct port_buffer *inbuf;
21206ede	72
38edf58d	73	/* For console ports, hvc != NULL and these are valid. */
21206ede RR	74	/* The hvc device */
21206ede RR	75	struct hvc_struct *hvc;
38edf58d AS	76
	77	/* We'll place all consoles in a list in the pdrvdata struct */
	78	struct list_head list;
	79
	80	/* Our vterm number. */
	81	u32 vtermno;
21206ede	82	};
31610434	83
971f3390 RR	84	/* This is the very early arch-specified put chars function. */
	85	static int (early_put_chars)(u32, const char , int);
	86
38edf58d AS	87	static struct port *find_port_by_vtermno(u32 vtermno)
	88	{
	89	struct port *port;
	90	unsigned long flags;
	91
	92	spin_lock_irqsave(&pdrvdata_lock, flags);
	93	list_for_each_entry(port, &pdrvdata.consoles, list) {
	94	if (port->vtermno == vtermno)
	95	goto out;
	96	}
	97	port = NULL;
	98	out:
	99	spin_unlock_irqrestore(&pdrvdata_lock, flags);
	100	return port;
	101	}
	102
fdb9a054 AS	103	static void free_buf(struct port_buffer *buf)
	104	{
	105	kfree(buf->buf);
	106	kfree(buf);
	107	}
	108
	109	static struct port_buffer *alloc_buf(size_t buf_size)
	110	{
	111	struct port_buffer *buf;
	112
	113	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
	114	if (!buf)
	115	goto fail;
	116	buf->buf = kzalloc(buf_size, GFP_KERNEL);
	117	if (!buf->buf)
	118	goto free_buf;
	119	buf->len = 0;
	120	buf->offset = 0;
	121	buf->size = buf_size;
	122	return buf;
	123
	124	free_buf:
	125	kfree(buf);
	126	fail:
	127	return NULL;
	128	}
	129
a3cde449 AS	130	/* Callers should take appropriate locks */
	131	static void get_inbuf(struct port port)
	132	{
	133	struct port_buffer *buf;
	134	struct virtqueue *vq;
	135	unsigned int len;
	136
	137	vq = port->in_vq;
	138	buf = vq->vq_ops->get_buf(vq, &len);
	139	if (buf) {
	140	buf->len = len;
	141	buf->offset = 0;
	142	}
	143	return buf;
	144	}
	145
e27b5198 AS	146	/*
	147	* Create a scatter-gather list representing our input buffer and put
	148	* it in the queue.
	149	*
	150	* Callers should take appropriate locks.
	151	*/
	152	static void add_inbuf(struct virtqueue vq, struct port_buffer buf)
	153	{
	154	struct scatterlist sg[1];
	155	sg_init_one(sg, buf->buf, buf->size);
	156
	157	if (vq->vq_ops->add_buf(vq, sg, 0, 1, buf) < 0)
	158	BUG();
	159	vq->vq_ops->kick(vq);
	160	}
	161
a23ea924 RR	162	/*
a23ea924 RR	163	* The put_chars() callback is pretty straightforward.
31610434	164	*
a23ea924 RR	165	* We turn the characters into a scatter-gather list, add it to the
	166	* output queue and then kick the Host. Then we sit here waiting for
	167	* it to finish: inefficient in theory, but in practice
	168	* implementations will do it immediately (lguest's Launcher does).
	169	*/
31610434 RR	170	static int put_chars(u32 vtermno, const char *buf, int count)
	171	{
	172	struct scatterlist sg[1];
21206ede	173	struct port *port;
38edf58d AS	174	unsigned int len;
	175
	176	port = find_port_by_vtermno(vtermno);
	177	if (!port)
	178	return 0;
31610434	179
971f3390 RR	180	if (unlikely(early_put_chars))
	181	return early_put_chars(vtermno, buf, count);
	182
31610434 RR	183	/* This is a convenient routine to initialize a single-elem sg list */
	184	sg_init_one(sg, buf, count);
	185
21206ede RR	186	/* This shouldn't fail: if it does, we lose chars. */
21206ede RR	187	if (port->out_vq->vq_ops->add_buf(port->out_vq, sg, 1, 0, port) >= 0) {
31610434	188	/* Tell Host to go! */
21206ede RR	189	port->out_vq->vq_ops->kick(port->out_vq);
21206ede RR	190	while (!port->out_vq->vq_ops->get_buf(port->out_vq, &len))
31610434 RR	191	cpu_relax();
	192	}
	193
	194	/* We're expected to return the amount of data we wrote: all of it. */
	195	return count;
	196	}
	197
a23ea924 RR	198	/*
	199	* get_chars() is the callback from the hvc_console infrastructure
	200	* when an interrupt is received.
31610434	201	*
a23ea924 RR	202	* Most of the code deals with the fact that the hvc_console()
	203	* infrastructure only asks us for 16 bytes at a time. We keep
	204	* in_offset and in_used fields for partially-filled buffers.
	205	*/
31610434 RR	206	static int get_chars(u32 vtermno, char *buf, int count)
31610434 RR	207	{
21206ede RR	208	struct port *port;
21206ede RR	209
38edf58d AS	210
	211	port = find_port_by_vtermno(vtermno);
	212	if (!port)
	213	return 0;
21206ede	214
31610434	215	/* If we don't have an input queue yet, we can't get input. */
21206ede	216	BUG_ON(!port->in_vq);
31610434	217
21206ede	218	/* No more in buffer? See if they've (re)used it. */
fdb9a054	219	if (port->inbuf->offset == port->inbuf->len) {
a3cde449	220	if (!get_inbuf(port))
31610434 RR	221	return 0;
	222	}
	223
	224	/* You want more than we have to give? Well, try wanting less! */
fdb9a054 AS	225	if (port->inbuf->offset + count > port->inbuf->len)
fdb9a054 AS	226	count = port->inbuf->len - port->inbuf->offset;
31610434 RR	227
31610434 RR	228	/* Copy across to their buffer and increment offset. */
fdb9a054 AS	229	memcpy(buf, port->inbuf->buf + port->inbuf->offset, count);
fdb9a054 AS	230	port->inbuf->offset += count;
31610434 RR	231
31610434 RR	232	/* Finished? Re-register buffer so Host will use it again. */
fdb9a054	233	if (port->inbuf->offset == port->inbuf->len)
e27b5198	234	add_inbuf(port->in_vq, port->inbuf);
31610434 RR	235
	236	return count;
	237	}
31610434	238
c2983458 CB	239	/*
	240	* virtio console configuration. This supports:
	241	* - console resize
	242	*/
	243	static void virtcons_apply_config(struct virtio_device *dev)
	244	{
73954488	245	struct port *port = dev->priv;
c2983458 CB	246	struct winsize ws;
	247
	248	if (virtio_has_feature(dev, VIRTIO_CONSOLE_F_SIZE)) {
	249	dev->config->get(dev,
	250	offsetof(struct virtio_console_config, cols),
	251	&ws.ws_col, sizeof(u16));
	252	dev->config->get(dev,
	253	offsetof(struct virtio_console_config, rows),
	254	&ws.ws_row, sizeof(u16));
73954488	255	hvc_resize(port->hvc, ws);
c2983458 CB	256	}
	257	}
	258
38edf58d	259	/* We set the configuration at this point, since we now have a tty */
91fcad19 CB	260	static int notifier_add_vio(struct hvc_struct *hp, int data)
91fcad19 CB	261	{
38edf58d AS	262	struct port *port;
	263
	264	port = find_port_by_vtermno(hp->vtermno);
	265	if (!port)
	266	return -EINVAL;
	267
91fcad19	268	hp->irq_requested = 1;
38edf58d	269	virtcons_apply_config(port->vdev);
c2983458	270
91fcad19 CB	271	return 0;
	272	}
	273
	274	static void notifier_del_vio(struct hvc_struct *hp, int data)
	275	{
	276	hp->irq_requested = 0;
	277	}
	278
	279	static void hvc_handle_input(struct virtqueue *vq)
	280	{
73954488 RR	281	struct port *port = vq->vdev->priv;
	282
	283	if (hvc_poll(port->hvc))
91fcad19 CB	284	hvc_kick();
	285	}
	286
971f3390	287	/* The operations for the console. */
1dff3996	288	static const struct hv_ops hv_ops = {
971f3390 RR	289	.get_chars = get_chars,
	290	.put_chars = put_chars,
	291	.notifier_add = notifier_add_vio,
	292	.notifier_del = notifier_del_vio,
	293	.notifier_hangup = notifier_del_vio,
	294	};
	295
	296	/*
	297	* Console drivers are initialized very early so boot messages can go
	298	* out, so we do things slightly differently from the generic virtio
	299	* initialization of the net and block drivers.
	300	*
	301	* At this stage, the console is output-only. It's too early to set
	302	* up a virtqueue, so we let the drivers do some boutique early-output
	303	* thing.
	304	*/
	305	int __init virtio_cons_early_init(int (put_chars)(u32, const char , int))
	306	{
	307	early_put_chars = put_chars;
	308	return hvc_instantiate(0, 0, &hv_ops);
	309	}
	310
d8a02bd5 RR	311	static struct port *__devinit add_port(u32 vtermno)
	312	{
	313	struct port *port;
	314
	315	port = kmalloc(sizeof(*port), GFP_KERNEL);
	316	if (!port)
	317	return NULL;
	318
	319	port->inbuf = alloc_buf(PAGE_SIZE);
	320	if (!port->inbuf) {
	321	kfree(port);
	322	return NULL;
	323	}
	324	port->hvc = NULL;
	325	port->vtermno = vtermno;
	326	return port;
	327	}
	328
	329	static void free_port(struct port *port)
	330	{
	331	free_buf(port->inbuf);
	332	kfree(port);
	333	}
	334
a23ea924 RR	335	/*
	336	* Once we're further in boot, we get probed like any other virtio
	337	* device. At this stage we set up the output virtqueue.
31610434	338	*
a23ea924 RR	339	* To set up and manage our virtual console, we call hvc_alloc().
	340	* Since we never remove the console device we never need this pointer
	341	* again.
31610434	342	*
a23ea924 RR	343	* Finally we put our input buffer in the input queue, ready to
	344	* receive.
	345	*/
21206ede	346	static int __devinit virtcons_probe(struct virtio_device *vdev)
31610434	347	{
d2a7ddda MT	348	vq_callback_t *callbacks[] = { hvc_handle_input, NULL};
	349	const char *names[] = { "input", "output" };
	350	struct virtqueue *vqs[2];
21206ede	351	struct port *port;
31610434	352	int err;
31610434	353
d8a02bd5 RR	354	port = add_port(pdrvdata.next_vtermno);
	355	if (!port) {
	356	err = -ENOMEM;
	357	goto fail;
f550804a	358	}
73954488 RR	359
73954488 RR	360	/* Attach this port to this virtio_device, and vice-versa. */
21206ede	361	port->vdev = vdev;
73954488	362	vdev->priv = port;
31610434	363
d2a7ddda	364	/* Find the queues. */
d2a7ddda MT	365	err = vdev->config->find_vqs(vdev, 2, vqs, callbacks, names);
d2a7ddda MT	366	if (err)
31610434	367	goto free;
31610434	368
21206ede RR	369	port->in_vq = vqs[0];
21206ede RR	370	port->out_vq = vqs[1];
31610434	371
a23ea924 RR	372	/*
a23ea924 RR	373	* The first argument of hvc_alloc() is the virtual console
d8a02bd5 RR	374	* number. The second argument is the parameter for the
	375	* notification mechanism (like irq number). We currently
	376	* leave this as zero, virtqueues have implicit notifications.
31610434	377	*
a23ea924 RR	378	* The third argument is a "struct hv_ops" containing the
	379	* put_chars(), get_chars(), notifier_add() and notifier_del()
	380	* pointers. The final argument is the output buffer size: we
	381	* can do any size, so we put PAGE_SIZE here.
	382	*/
d8a02bd5	383	port->hvc = hvc_alloc(port->vtermno, 0, &hv_ops, PAGE_SIZE);
21206ede RR	384	if (IS_ERR(port->hvc)) {
21206ede RR	385	err = PTR_ERR(port->hvc);
d2a7ddda	386	goto free_vqs;
31610434 RR	387	}
31610434 RR	388
38edf58d AS	389	/* Add to vtermno list. */
38edf58d AS	390	spin_lock_irq(&pdrvdata_lock);
d8a02bd5	391	pdrvdata.next_vtermno++;
38edf58d AS	392	list_add(&port->list, &pdrvdata.consoles);
	393	spin_unlock_irq(&pdrvdata_lock);
	394
31610434	395	/* Register the input buffer the first time. */
e27b5198	396	add_inbuf(port->in_vq, port->inbuf);
971f3390 RR	397
	398	/* Start using the new console output. */
	399	early_put_chars = NULL;
31610434 RR	400	return 0;
31610434 RR	401
d2a7ddda MT	402	free_vqs:
d2a7ddda MT	403	vdev->config->del_vqs(vdev);
31610434	404	free:
d8a02bd5	405	free_port(port);
31610434 RR	406	fail:
	407	return err;
	408	}
	409
	410	static struct virtio_device_id id_table[] = {
	411	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
	412	{ 0 },
	413	};
	414
c2983458 CB	415	static unsigned int features[] = {
	416	VIRTIO_CONSOLE_F_SIZE,
	417	};
	418
31610434	419	static struct virtio_driver virtio_console = {
c2983458 CB	420	.feature_table = features,
c2983458 CB	421	.feature_table_size = ARRAY_SIZE(features),
31610434 RR	422	.driver.name = KBUILD_MODNAME,
	423	.driver.owner = THIS_MODULE,
	424	.id_table = id_table,
	425	.probe = virtcons_probe,
c2983458	426	.config_changed = virtcons_apply_config,
31610434 RR	427	};
	428
	429	static int __init init(void)
	430	{
38edf58d AS	431	INIT_LIST_HEAD(&pdrvdata.consoles);
38edf58d AS	432
31610434 RR	433	return register_virtio_driver(&virtio_console);
	434	}
	435	module_init(init);
	436
	437	MODULE_DEVICE_TABLE(virtio, id_table);
	438	MODULE_DESCRIPTION("Virtio console driver");
	439	MODULE_LICENSE("GPL");