[deliverable/linux.git] / drivers / virtio / virtio.c

#include <linux/virtio.h>
#include <linux/spinlock.h>
#include <linux/virtio_config.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <uapi/linux/virtio_ids.h>

/* Unique numbering for virtio devices. */
static DEFINE_IDA(virtio_index_ida);

static ssize_t device_show(struct device *_d,
			   struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = dev_to_virtio(_d);
	return sprintf(buf, "0x%04x\n", dev->id.device);
}
static DEVICE_ATTR_RO(device);

static ssize_t vendor_show(struct device *_d,
			   struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = dev_to_virtio(_d);
	return sprintf(buf, "0x%04x\n", dev->id.vendor);
}
static DEVICE_ATTR_RO(vendor);

static ssize_t status_show(struct device *_d,
			   struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = dev_to_virtio(_d);
	return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
}
static DEVICE_ATTR_RO(status);

static ssize_t modalias_show(struct device *_d,
			     struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = dev_to_virtio(_d);
	return sprintf(buf, "virtio:d%08Xv%08X\n",
		       dev->id.device, dev->id.vendor);
}
static DEVICE_ATTR_RO(modalias);

static ssize_t features_show(struct device *_d,
			     struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = dev_to_virtio(_d);
	unsigned int i;
	ssize_t len = 0;

	/* We actually represent this as a bitstring, as it could be
	 * arbitrary length in future. */
	for (i = 0; i < sizeof(dev->features)*8; i++)
		len += sprintf(buf+len, "%c",
			       __virtio_test_bit(dev, i) ? '1' : '0');
	len += sprintf(buf+len, "\n");
	return len;
}
static DEVICE_ATTR_RO(features);

static struct attribute *virtio_dev_attrs[] = {
	&dev_attr_device.attr,
	&dev_attr_vendor.attr,
	&dev_attr_status.attr,
	&dev_attr_modalias.attr,
	&dev_attr_features.attr,
	NULL,
};
ATTRIBUTE_GROUPS(virtio_dev);

static inline int virtio_id_match(const struct virtio_device *dev,
				  const struct virtio_device_id *id)
{
	if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
		return 0;

	return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
}

/* This looks through all the IDs a driver claims to support.  If any of them
 * match, we return 1 and the kernel will call virtio_dev_probe(). */
static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
{
	unsigned int i;
	struct virtio_device *dev = dev_to_virtio(_dv);
	const struct virtio_device_id *ids;

	ids = drv_to_virtio(_dr)->id_table;
	for (i = 0; ids[i].device; i++)
		if (virtio_id_match(dev, &ids[i]))
			return 1;
	return 0;
}

static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
{
	struct virtio_device *dev = dev_to_virtio(_dv);

	return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
			      dev->id.device, dev->id.vendor);
}

static void add_status(struct virtio_device *dev, unsigned status)
{
	dev->config->set_status(dev, dev->config->get_status(dev) | status);
}

void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
					 unsigned int fbit)
{
	unsigned int i;
	struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);

	for (i = 0; i < drv->feature_table_size; i++)
		if (drv->feature_table[i] == fbit)
			return;

	if (drv->feature_table_legacy) {
		for (i = 0; i < drv->feature_table_size_legacy; i++)
			if (drv->feature_table_legacy[i] == fbit)
				return;
	}

	BUG();
}
EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);

static void __virtio_config_changed(struct virtio_device *dev)
{
	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);

	if (!dev->config_enabled)
		dev->config_change_pending = true;
	else if (drv && drv->config_changed)
		drv->config_changed(dev);
}

void virtio_config_changed(struct virtio_device *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&dev->config_lock, flags);
	__virtio_config_changed(dev);
	spin_unlock_irqrestore(&dev->config_lock, flags);
}
EXPORT_SYMBOL_GPL(virtio_config_changed);

static void virtio_config_disable(struct virtio_device *dev)
{
	spin_lock_irq(&dev->config_lock);
	dev->config_enabled = false;
	spin_unlock_irq(&dev->config_lock);
}

static void virtio_config_enable(struct virtio_device *dev)
{
	spin_lock_irq(&dev->config_lock);
	dev->config_enabled = true;
	if (dev->config_change_pending)
		__virtio_config_changed(dev);
	dev->config_change_pending = false;
	spin_unlock_irq(&dev->config_lock);
}

static int virtio_finalize_features(struct virtio_device *dev)
{
	int ret = dev->config->finalize_features(dev);
	unsigned status;

	if (ret)
		return ret;

	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
		return 0;

	add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
	status = dev->config->get_status(dev);
	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
		dev_err(&dev->dev, "virtio: device refuses features: %x\n",
			status);
		return -ENODEV;
	}
	return 0;
}

static int virtio_dev_probe(struct device *_d)
{
	int err, i;
	struct virtio_device *dev = dev_to_virtio(_d);
	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	u64 device_features;
	u64 driver_features;
	u64 driver_features_legacy;

	/* We have a driver! */
	add_status(dev, VIRTIO_CONFIG_S_DRIVER);

	/* Figure out what features the device supports. */
	device_features = dev->config->get_features(dev);

	/* Figure out what features the driver supports. */
	driver_features = 0;
	for (i = 0; i < drv->feature_table_size; i++) {
		unsigned int f = drv->feature_table[i];
		BUG_ON(f >= 64);
		driver_features |= (1ULL << f);
	}

	/* Some drivers have a separate feature table for virtio v1.0 */
	if (drv->feature_table_legacy) {
		driver_features_legacy = 0;
		for (i = 0; i < drv->feature_table_size_legacy; i++) {
			unsigned int f = drv->feature_table_legacy[i];
			BUG_ON(f >= 64);
			driver_features_legacy |= (1ULL << f);
		}
	} else {
		driver_features_legacy = driver_features;
	}

	if (device_features & (1ULL << VIRTIO_F_VERSION_1))
		dev->features = driver_features & device_features;
	else
		dev->features = driver_features_legacy & device_features;

	/* Transport features always preserved to pass to finalize_features. */
	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
		if (device_features & (1ULL << i))
			__virtio_set_bit(dev, i);

	err = virtio_finalize_features(dev);
	if (err)
		goto err;

	err = drv->probe(dev);
	if (err)
		goto err;

	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
		virtio_device_ready(dev);

	if (drv->scan)
		drv->scan(dev);

	virtio_config_enable(dev);

	return 0;
err:
	add_status(dev, VIRTIO_CONFIG_S_FAILED);
	return err;

}

static int virtio_dev_remove(struct device *_d)
{
	struct virtio_device *dev = dev_to_virtio(_d);
	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);

	virtio_config_disable(dev);

	drv->remove(dev);

	/* Driver should have reset device. */
	WARN_ON_ONCE(dev->config->get_status(dev));

	/* Acknowledge the device's existence again. */
	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
	return 0;
}

static struct bus_type virtio_bus = {
	.name  = "virtio",
	.match = virtio_dev_match,
	.dev_groups = virtio_dev_groups,
	.uevent = virtio_uevent,
	.probe = virtio_dev_probe,
	.remove = virtio_dev_remove,
};

int register_virtio_driver(struct virtio_driver *driver)
{
	/* Catch this early. */
	BUG_ON(driver->feature_table_size && !driver->feature_table);
	driver->driver.bus = &virtio_bus;
	return driver_register(&driver->driver);
}
EXPORT_SYMBOL_GPL(register_virtio_driver);

void unregister_virtio_driver(struct virtio_driver *driver)
{
	driver_unregister(&driver->driver);
}
EXPORT_SYMBOL_GPL(unregister_virtio_driver);

int register_virtio_device(struct virtio_device *dev)
{
	int err;

	dev->dev.bus = &virtio_bus;

	/* Assign a unique device index and hence name. */
	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
	if (err < 0)
		goto out;

	dev->index = err;
	dev_set_name(&dev->dev, "virtio%u", dev->index);

	spin_lock_init(&dev->config_lock);
	dev->config_enabled = false;
	dev->config_change_pending = false;

	/* We always start by resetting the device, in case a previous
	 * driver messed it up.  This also tests that code path a little. */
	dev->config->reset(dev);

	/* Acknowledge that we've seen the device. */
	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);

	INIT_LIST_HEAD(&dev->vqs);

	/* device_register() causes the bus infrastructure to look for a
	 * matching driver. */
	err = device_register(&dev->dev);
out:
	if (err)
		add_status(dev, VIRTIO_CONFIG_S_FAILED);
	return err;
}
EXPORT_SYMBOL_GPL(register_virtio_device);

void unregister_virtio_device(struct virtio_device *dev)
{
	int index = dev->index; /* save for after device release */

	device_unregister(&dev->dev);
	ida_simple_remove(&virtio_index_ida, index);
}
EXPORT_SYMBOL_GPL(unregister_virtio_device);

#ifdef CONFIG_PM_SLEEP
int virtio_device_freeze(struct virtio_device *dev)
{
	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);

	virtio_config_disable(dev);

	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;

	if (drv && drv->freeze)
		return drv->freeze(dev);

	return 0;
}
EXPORT_SYMBOL_GPL(virtio_device_freeze);

int virtio_device_restore(struct virtio_device *dev)
{
	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	int ret;

	/* We always start by resetting the device, in case a previous
	 * driver messed it up. */
	dev->config->reset(dev);

	/* Acknowledge that we've seen the device. */
	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);

	/* Maybe driver failed before freeze.
	 * Restore the failed status, for debugging. */
	if (dev->failed)
		add_status(dev, VIRTIO_CONFIG_S_FAILED);

	if (!drv)
		return 0;

	/* We have a driver! */
	add_status(dev, VIRTIO_CONFIG_S_DRIVER);

	ret = virtio_finalize_features(dev);
	if (ret)
		goto err;

	if (drv->restore) {
		ret = drv->restore(dev);
		if (ret)
			goto err;
	}

	/* Finally, tell the device we're all set */
	add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);

	virtio_config_enable(dev);

	return 0;

err:
	add_status(dev, VIRTIO_CONFIG_S_FAILED);
	return ret;
}
EXPORT_SYMBOL_GPL(virtio_device_restore);
#endif

static int virtio_init(void)
{
	if (bus_register(&virtio_bus) != 0)
		panic("virtio bus registration failed");
	return 0;
}

static void __exit virtio_exit(void)
{
	bus_unregister(&virtio_bus);
	ida_destroy(&virtio_index_ida);
}
core_initcall(virtio_init);
module_exit(virtio_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
ec3d41c4 RR	1	#include <linux/virtio.h>
	2	#include <linux/spinlock.h>
	3	#include <linux/virtio_config.h>
b5a2c4f1	4	#include <linux/module.h>
90e03207	5	#include <linux/idr.h>
b6098c30	6	#include <uapi/linux/virtio_ids.h>
ec3d41c4	7
b769f579	8	/* Unique numbering for virtio devices. */
90e03207	9	static DEFINE_IDA(virtio_index_ida);
b769f579	10
ec3d41c4 RR	11	static ssize_t device_show(struct device *_d,
	12	struct device_attribute attr, char buf)
	13	{
9bffdca8	14	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	15	return sprintf(buf, "0x%04x\n", dev->id.device);
ec3d41c4	16	}
3736dab6 GKH	17	static DEVICE_ATTR_RO(device);
3736dab6 GKH	18
ec3d41c4 RR	19	static ssize_t vendor_show(struct device *_d,
	20	struct device_attribute attr, char buf)
	21	{
9bffdca8	22	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	23	return sprintf(buf, "0x%04x\n", dev->id.vendor);
ec3d41c4	24	}
3736dab6 GKH	25	static DEVICE_ATTR_RO(vendor);
3736dab6 GKH	26
ec3d41c4 RR	27	static ssize_t status_show(struct device *_d,
	28	struct device_attribute attr, char buf)
	29	{
9bffdca8	30	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	31	return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
ec3d41c4	32	}
3736dab6 GKH	33	static DEVICE_ATTR_RO(status);
3736dab6 GKH	34
b01d9f28 RR	35	static ssize_t modalias_show(struct device *_d,
	36	struct device_attribute attr, char buf)
	37	{
9bffdca8	38	struct virtio_device *dev = dev_to_virtio(_d);
b01d9f28 RR	39	return sprintf(buf, "virtio:d%08Xv%08X\n",
	40	dev->id.device, dev->id.vendor);
	41	}
3736dab6 GKH	42	static DEVICE_ATTR_RO(modalias);
3736dab6 GKH	43
a9289282 RR	44	static ssize_t features_show(struct device *_d,
	45	struct device_attribute attr, char buf)
	46	{
9bffdca8	47	struct virtio_device *dev = dev_to_virtio(_d);
a9289282 RR	48	unsigned int i;
	49	ssize_t len = 0;
	50
	51	/* We actually represent this as a bitstring, as it could be
	52	* arbitrary length in future. */
e16e12be	53	for (i = 0; i < sizeof(dev->features)*8; i++)
a9289282	54	len += sprintf(buf+len, "%c",
e16e12be	55	__virtio_test_bit(dev, i) ? '1' : '0');
a9289282 RR	56	len += sprintf(buf+len, "\n");
	57	return len;
	58	}
3736dab6 GKH	59	static DEVICE_ATTR_RO(features);
	60
	61	static struct attribute *virtio_dev_attrs[] = {
	62	&dev_attr_device.attr,
	63	&dev_attr_vendor.attr,
	64	&dev_attr_status.attr,
	65	&dev_attr_modalias.attr,
	66	&dev_attr_features.attr,
	67	NULL,
ec3d41c4	68	};
3736dab6	69	ATTRIBUTE_GROUPS(virtio_dev);
ec3d41c4 RR	70
	71	static inline int virtio_id_match(const struct virtio_device *dev,
	72	const struct virtio_device_id *id)
	73	{
e3353853	74	if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
ec3d41c4 RR	75	return 0;
ec3d41c4 RR	76
c89e8016	77	return id->vendor == VIRTIO_DEV_ANY_ID \|\| id->vendor == dev->id.vendor;
ec3d41c4 RR	78	}
	79
	80	/* This looks through all the IDs a driver claims to support. If any of them
	81	* match, we return 1 and the kernel will call virtio_dev_probe(). */
	82	static int virtio_dev_match(struct device _dv, struct device_driver _dr)
	83	{
	84	unsigned int i;
9bffdca8	85	struct virtio_device *dev = dev_to_virtio(_dv);
ec3d41c4 RR	86	const struct virtio_device_id *ids;
ec3d41c4 RR	87
9a2bdcc8	88	ids = drv_to_virtio(_dr)->id_table;
ec3d41c4 RR	89	for (i = 0; ids[i].device; i++)
	90	if (virtio_id_match(dev, &ids[i]))
	91	return 1;
	92	return 0;
	93	}
	94
b01d9f28 RR	95	static int virtio_uevent(struct device _dv, struct kobj_uevent_env env)
b01d9f28 RR	96	{
9bffdca8	97	struct virtio_device *dev = dev_to_virtio(_dv);
b01d9f28 RR	98
	99	return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
	100	dev->id.device, dev->id.vendor);
	101	}
	102
ec3d41c4 RR	103	static void add_status(struct virtio_device *dev, unsigned status)
	104	{
	105	dev->config->set_status(dev, dev->config->get_status(dev) \| status);
	106	}
	107
c45a6816 RR	108	void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
	109	unsigned int fbit)
	110	{
	111	unsigned int i;
9a2bdcc8	112	struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
c45a6816 RR	113
	114	for (i = 0; i < drv->feature_table_size; i++)
	115	if (drv->feature_table[i] == fbit)
	116	return;
b3bb62d1 MT	117
	118	if (drv->feature_table_legacy) {
	119	for (i = 0; i < drv->feature_table_size_legacy; i++)
	120	if (drv->feature_table_legacy[i] == fbit)
	121	return;
	122	}
	123
c45a6816 RR	124	BUG();
	125	}
	126	EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
	127
22b7050a MT	128	static void __virtio_config_changed(struct virtio_device *dev)
	129	{
	130	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	131
	132	if (!dev->config_enabled)
	133	dev->config_change_pending = true;
	134	else if (drv && drv->config_changed)
	135	drv->config_changed(dev);
	136	}
	137
	138	void virtio_config_changed(struct virtio_device *dev)
	139	{
	140	unsigned long flags;
	141
	142	spin_lock_irqsave(&dev->config_lock, flags);
	143	__virtio_config_changed(dev);
	144	spin_unlock_irqrestore(&dev->config_lock, flags);
	145	}
	146	EXPORT_SYMBOL_GPL(virtio_config_changed);
	147
	148	static void virtio_config_disable(struct virtio_device *dev)
	149	{
	150	spin_lock_irq(&dev->config_lock);
	151	dev->config_enabled = false;
	152	spin_unlock_irq(&dev->config_lock);
	153	}
	154
	155	static void virtio_config_enable(struct virtio_device *dev)
	156	{
	157	spin_lock_irq(&dev->config_lock);
	158	dev->config_enabled = true;
	159	if (dev->config_change_pending)
	160	__virtio_config_changed(dev);
	161	dev->config_change_pending = false;
	162	spin_unlock_irq(&dev->config_lock);
	163	}
	164
30683a8c MT	165	static int virtio_finalize_features(struct virtio_device *dev)
	166	{
	167	int ret = dev->config->finalize_features(dev);
	168	unsigned status;
	169
	170	if (ret)
	171	return ret;
	172
	173	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
	174	return 0;
	175
	176	add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
	177	status = dev->config->get_status(dev);
	178	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
	179	dev_err(&dev->dev, "virtio: device refuses features: %x\n",
	180	status);
	181	return -ENODEV;
	182	}
	183	return 0;
	184	}
	185
ec3d41c4 RR	186	static int virtio_dev_probe(struct device *_d)
ec3d41c4 RR	187	{
c45a6816	188	int err, i;
9bffdca8	189	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	190	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
d0254773	191	u64 device_features;
c102659d	192	u64 driver_features;
b3bb62d1	193	u64 driver_features_legacy;
ec3d41c4	194
c45a6816	195	/* We have a driver! */
ec3d41c4	196	add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c45a6816 RR	197
	198	/* Figure out what features the device supports. */
	199	device_features = dev->config->get_features(dev);
	200
c102659d MT	201	/* Figure out what features the driver supports. */
c102659d MT	202	driver_features = 0;
c45a6816 RR	203	for (i = 0; i < drv->feature_table_size; i++) {
c45a6816 RR	204	unsigned int f = drv->feature_table[i];
d0254773	205	BUG_ON(f >= 64);
c102659d	206	driver_features \|= (1ULL << f);
c45a6816 RR	207	}
c45a6816 RR	208
b3bb62d1 MT	209	/* Some drivers have a separate feature table for virtio v1.0 */
	210	if (drv->feature_table_legacy) {
	211	driver_features_legacy = 0;
	212	for (i = 0; i < drv->feature_table_size_legacy; i++) {
	213	unsigned int f = drv->feature_table_legacy[i];
	214	BUG_ON(f >= 64);
	215	driver_features_legacy \|= (1ULL << f);
	216	}
	217	} else {
	218	driver_features_legacy = driver_features;
	219	}
	220
747ae34a	221	if (device_features & (1ULL << VIRTIO_F_VERSION_1))
b3bb62d1 MT	222	dev->features = driver_features & device_features;
	223	else
	224	dev->features = driver_features_legacy & device_features;
c102659d	225
c624896e	226	/* Transport features always preserved to pass to finalize_features. */
dd7c7bc4	227	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
d0254773	228	if (device_features & (1ULL << i))
e16e12be	229	__virtio_set_bit(dev, i);
dd7c7bc4	230
30683a8c	231	err = virtio_finalize_features(dev);
5c609a5e MT	232	if (err)
5c609a5e MT	233	goto err;
ef688e15	234
ec3d41c4 RR	235	err = drv->probe(dev);
ec3d41c4 RR	236	if (err)
cb3f6d9d	237	goto err;
22b7050a	238
5b40a7da RR	239	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
	240	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
	241	virtio_device_ready(dev);
	242
cb3f6d9d MT	243	if (drv->scan)
cb3f6d9d MT	244	drv->scan(dev);
ef688e15	245
cb3f6d9d MT	246	virtio_config_enable(dev);
	247
	248	return 0;
	249	err:
	250	add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4	251	return err;
cb3f6d9d	252
ec3d41c4 RR	253	}
ec3d41c4 RR	254
74b2553f RR	255	static int virtio_dev_remove(struct device *_d)
74b2553f RR	256	{
9bffdca8	257	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	258	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
74b2553f	259
22b7050a MT	260	virtio_config_disable(dev);
22b7050a MT	261
74b2553f	262	drv->remove(dev);
6e5aa7ef RR	263
6e5aa7ef RR	264	/* Driver should have reset device. */
5543a6ac	265	WARN_ON_ONCE(dev->config->get_status(dev));
6e5aa7ef RR	266
	267	/* Acknowledge the device's existence again. */
	268	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
74b2553f RR	269	return 0;
	270	}
	271
e962fa66 MM	272	static struct bus_type virtio_bus = {
	273	.name = "virtio",
	274	.match = virtio_dev_match,
3736dab6	275	.dev_groups = virtio_dev_groups,
e962fa66 MM	276	.uevent = virtio_uevent,
	277	.probe = virtio_dev_probe,
	278	.remove = virtio_dev_remove,
	279	};
	280
ec3d41c4 RR	281	int register_virtio_driver(struct virtio_driver *driver)
ec3d41c4 RR	282	{
c45a6816 RR	283	/* Catch this early. */
c45a6816 RR	284	BUG_ON(driver->feature_table_size && !driver->feature_table);
ec3d41c4	285	driver->driver.bus = &virtio_bus;
ec3d41c4 RR	286	return driver_register(&driver->driver);
	287	}
	288	EXPORT_SYMBOL_GPL(register_virtio_driver);
	289
	290	void unregister_virtio_driver(struct virtio_driver *driver)
	291	{
	292	driver_unregister(&driver->driver);
	293	}
	294	EXPORT_SYMBOL_GPL(unregister_virtio_driver);
	295
	296	int register_virtio_device(struct virtio_device *dev)
	297	{
	298	int err;
	299
	300	dev->dev.bus = &virtio_bus;
b769f579 RR	301
b769f579 RR	302	/* Assign a unique device index and hence name. */
90e03207 AH	303	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
	304	if (err < 0)
	305	goto out;
	306
	307	dev->index = err;
99e0b6c8	308	dev_set_name(&dev->dev, "virtio%u", dev->index);
ec3d41c4	309
22b7050a MT	310	spin_lock_init(&dev->config_lock);
	311	dev->config_enabled = false;
	312	dev->config_change_pending = false;
	313
6e5aa7ef RR	314	/* We always start by resetting the device, in case a previous
	315	* driver messed it up. This also tests that code path a little. */
	316	dev->config->reset(dev);
	317
ec3d41c4 RR	318	/* Acknowledge that we've seen the device. */
	319	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
	320
9499f5e7 RR	321	INIT_LIST_HEAD(&dev->vqs);
9499f5e7 RR	322
ec3d41c4 RR	323	/* device_register() causes the bus infrastructure to look for a
	324	* matching driver. */
	325	err = device_register(&dev->dev);
90e03207	326	out:
ec3d41c4 RR	327	if (err)
	328	add_status(dev, VIRTIO_CONFIG_S_FAILED);
	329	return err;
	330	}
	331	EXPORT_SYMBOL_GPL(register_virtio_device);
	332
	333	void unregister_virtio_device(struct virtio_device *dev)
	334	{
237242bd CH	335	int index = dev->index; /* save for after device release */
237242bd CH	336
ec3d41c4	337	device_unregister(&dev->dev);
237242bd	338	ida_simple_remove(&virtio_index_ida, index);
ec3d41c4 RR	339	}
	340	EXPORT_SYMBOL_GPL(unregister_virtio_device);
	341
c6716bae MT	342	#ifdef CONFIG_PM_SLEEP
	343	int virtio_device_freeze(struct virtio_device *dev)
	344	{
	345	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	346
22b7050a MT	347	virtio_config_disable(dev);
22b7050a MT	348
c6716bae MT	349	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
	350
	351	if (drv && drv->freeze)
	352	return drv->freeze(dev);
	353
	354	return 0;
	355	}
	356	EXPORT_SYMBOL_GPL(virtio_device_freeze);
	357
	358	int virtio_device_restore(struct virtio_device *dev)
	359	{
	360	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
5c609a5e	361	int ret;
c6716bae MT	362
	363	/* We always start by resetting the device, in case a previous
	364	* driver messed it up. */
	365	dev->config->reset(dev);
	366
	367	/* Acknowledge that we've seen the device. */
	368	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
	369
	370	/* Maybe driver failed before freeze.
	371	* Restore the failed status, for debugging. */
	372	if (dev->failed)
	373	add_status(dev, VIRTIO_CONFIG_S_FAILED);
	374
	375	if (!drv)
	376	return 0;
	377
	378	/* We have a driver! */
	379	add_status(dev, VIRTIO_CONFIG_S_DRIVER);
	380
30683a8c	381	ret = virtio_finalize_features(dev);
5c609a5e MT	382	if (ret)
5c609a5e MT	383	goto err;
c6716bae MT	384
c6716bae MT	385	if (drv->restore) {
5c609a5e MT	386	ret = drv->restore(dev);
	387	if (ret)
	388	goto err;
c6716bae MT	389	}
	390
	391	/* Finally, tell the device we're all set */
	392	add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
	393
22b7050a MT	394	virtio_config_enable(dev);
22b7050a MT	395
c6716bae	396	return 0;
5c609a5e MT	397
	398	err:
	399	add_status(dev, VIRTIO_CONFIG_S_FAILED);
	400	return ret;
c6716bae MT	401	}
	402	EXPORT_SYMBOL_GPL(virtio_device_restore);
	403	#endif
	404
ec3d41c4 RR	405	static int virtio_init(void)
	406	{
	407	if (bus_register(&virtio_bus) != 0)
	408	panic("virtio bus registration failed");
	409	return 0;
	410	}
c6fd4701 RR	411
	412	static void __exit virtio_exit(void)
	413	{
	414	bus_unregister(&virtio_bus);
c13f99b7	415	ida_destroy(&virtio_index_ida);
c6fd4701	416	}
ec3d41c4	417	core_initcall(virtio_init);
c6fd4701 RR	418	module_exit(virtio_exit);
	419
	420	MODULE_LICENSE("GPL");