[mirror_ubuntu-bionic-kernel.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);
}

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);

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

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);
}
EXPORT_SYMBOL_GPL(virtio_config_enable);

void virtio_add_status(struct virtio_device *dev, unsigned int status)
{
	dev->config->set_status(dev, dev->config->get_status(dev) | status);
}
EXPORT_SYMBOL_GPL(virtio_add_status);

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;

	virtio_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;
}
EXPORT_SYMBOL_GPL(virtio_finalize_features);

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! */
	virtio_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);

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

	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:
	virtio_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. */
	virtio_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. */
	virtio_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);
	if (err)
		ida_simple_remove(&virtio_index_ida, dev->index);
out:
	if (err)
		virtio_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. */
	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);

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

	if (!drv)
		return 0;

	/* We have a driver! */
	virtio_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 */
	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);

	virtio_config_enable(dev);

	return 0;

err:
	virtio_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
c45a6816 RR	103	void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
	104	unsigned int fbit)
	105	{
	106	unsigned int i;
9a2bdcc8	107	struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
c45a6816 RR	108
	109	for (i = 0; i < drv->feature_table_size; i++)
	110	if (drv->feature_table[i] == fbit)
	111	return;
b3bb62d1 MT	112
	113	if (drv->feature_table_legacy) {
	114	for (i = 0; i < drv->feature_table_size_legacy; i++)
	115	if (drv->feature_table_legacy[i] == fbit)
	116	return;
	117	}
	118
c45a6816 RR	119	BUG();
	120	}
	121	EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
	122
22b7050a MT	123	static void __virtio_config_changed(struct virtio_device *dev)
	124	{
	125	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	126
	127	if (!dev->config_enabled)
	128	dev->config_change_pending = true;
	129	else if (drv && drv->config_changed)
	130	drv->config_changed(dev);
	131	}
	132
	133	void virtio_config_changed(struct virtio_device *dev)
	134	{
	135	unsigned long flags;
	136
	137	spin_lock_irqsave(&dev->config_lock, flags);
	138	__virtio_config_changed(dev);
	139	spin_unlock_irqrestore(&dev->config_lock, flags);
	140	}
	141	EXPORT_SYMBOL_GPL(virtio_config_changed);
	142
9fe7bfce	143	void virtio_config_disable(struct virtio_device *dev)
22b7050a MT	144	{
	145	spin_lock_irq(&dev->config_lock);
	146	dev->config_enabled = false;
	147	spin_unlock_irq(&dev->config_lock);
	148	}
9fe7bfce	149	EXPORT_SYMBOL_GPL(virtio_config_disable);
22b7050a	150
9fe7bfce	151	void virtio_config_enable(struct virtio_device *dev)
22b7050a MT	152	{
	153	spin_lock_irq(&dev->config_lock);
	154	dev->config_enabled = true;
	155	if (dev->config_change_pending)
	156	__virtio_config_changed(dev);
	157	dev->config_change_pending = false;
	158	spin_unlock_irq(&dev->config_lock);
	159	}
9fe7bfce JF	160	EXPORT_SYMBOL_GPL(virtio_config_enable);
	161
	162	void virtio_add_status(struct virtio_device *dev, unsigned int status)
	163	{
	164	dev->config->set_status(dev, dev->config->get_status(dev) \| status);
	165	}
	166	EXPORT_SYMBOL_GPL(virtio_add_status);
22b7050a	167
9fe7bfce	168	int virtio_finalize_features(struct virtio_device *dev)
30683a8c MT	169	{
	170	int ret = dev->config->finalize_features(dev);
	171	unsigned status;
	172
	173	if (ret)
	174	return ret;
	175
	176	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
	177	return 0;
	178
9fe7bfce	179	virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
30683a8c MT	180	status = dev->config->get_status(dev);
	181	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
	182	dev_err(&dev->dev, "virtio: device refuses features: %x\n",
	183	status);
	184	return -ENODEV;
	185	}
	186	return 0;
	187	}
9fe7bfce	188	EXPORT_SYMBOL_GPL(virtio_finalize_features);
30683a8c	189
ec3d41c4 RR	190	static int virtio_dev_probe(struct device *_d)
ec3d41c4 RR	191	{
c45a6816	192	int err, i;
9bffdca8	193	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	194	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
d0254773	195	u64 device_features;
c102659d	196	u64 driver_features;
b3bb62d1	197	u64 driver_features_legacy;
ec3d41c4	198
c45a6816	199	/* We have a driver! */
9fe7bfce	200	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c45a6816 RR	201
	202	/* Figure out what features the device supports. */
	203	device_features = dev->config->get_features(dev);
	204
c102659d MT	205	/* Figure out what features the driver supports. */
c102659d MT	206	driver_features = 0;
c45a6816 RR	207	for (i = 0; i < drv->feature_table_size; i++) {
c45a6816 RR	208	unsigned int f = drv->feature_table[i];
d0254773	209	BUG_ON(f >= 64);
c102659d	210	driver_features \|= (1ULL << f);
c45a6816 RR	211	}
c45a6816 RR	212
b3bb62d1 MT	213	/* Some drivers have a separate feature table for virtio v1.0 */
	214	if (drv->feature_table_legacy) {
	215	driver_features_legacy = 0;
	216	for (i = 0; i < drv->feature_table_size_legacy; i++) {
	217	unsigned int f = drv->feature_table_legacy[i];
	218	BUG_ON(f >= 64);
	219	driver_features_legacy \|= (1ULL << f);
	220	}
	221	} else {
	222	driver_features_legacy = driver_features;
	223	}
	224
747ae34a	225	if (device_features & (1ULL << VIRTIO_F_VERSION_1))
b3bb62d1 MT	226	dev->features = driver_features & device_features;
	227	else
	228	dev->features = driver_features_legacy & device_features;
c102659d	229
c624896e	230	/* Transport features always preserved to pass to finalize_features. */
dd7c7bc4	231	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
d0254773	232	if (device_features & (1ULL << i))
e16e12be	233	__virtio_set_bit(dev, i);
dd7c7bc4	234
404123c2 MT	235	if (drv->validate) {
	236	err = drv->validate(dev);
	237	if (err)
	238	goto err;
	239	}
	240
30683a8c	241	err = virtio_finalize_features(dev);
5c609a5e MT	242	if (err)
5c609a5e MT	243	goto err;
ef688e15	244
ec3d41c4 RR	245	err = drv->probe(dev);
ec3d41c4 RR	246	if (err)
cb3f6d9d	247	goto err;
22b7050a	248
5b40a7da RR	249	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
	250	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
	251	virtio_device_ready(dev);
	252
cb3f6d9d MT	253	if (drv->scan)
cb3f6d9d MT	254	drv->scan(dev);
ef688e15	255
cb3f6d9d MT	256	virtio_config_enable(dev);
	257
	258	return 0;
	259	err:
9fe7bfce	260	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4	261	return err;
cb3f6d9d	262
ec3d41c4 RR	263	}
ec3d41c4 RR	264
74b2553f RR	265	static int virtio_dev_remove(struct device *_d)
74b2553f RR	266	{
9bffdca8	267	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	268	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
74b2553f	269
22b7050a MT	270	virtio_config_disable(dev);
22b7050a MT	271
74b2553f	272	drv->remove(dev);
6e5aa7ef RR	273
6e5aa7ef RR	274	/* Driver should have reset device. */
5543a6ac	275	WARN_ON_ONCE(dev->config->get_status(dev));
6e5aa7ef RR	276
6e5aa7ef RR	277	/* Acknowledge the device's existence again. */
9fe7bfce	278	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
74b2553f RR	279	return 0;
	280	}
	281
e962fa66 MM	282	static struct bus_type virtio_bus = {
	283	.name = "virtio",
	284	.match = virtio_dev_match,
3736dab6	285	.dev_groups = virtio_dev_groups,
e962fa66 MM	286	.uevent = virtio_uevent,
	287	.probe = virtio_dev_probe,
	288	.remove = virtio_dev_remove,
	289	};
	290
ec3d41c4 RR	291	int register_virtio_driver(struct virtio_driver *driver)
ec3d41c4 RR	292	{
c45a6816 RR	293	/* Catch this early. */
c45a6816 RR	294	BUG_ON(driver->feature_table_size && !driver->feature_table);
ec3d41c4	295	driver->driver.bus = &virtio_bus;
ec3d41c4 RR	296	return driver_register(&driver->driver);
	297	}
	298	EXPORT_SYMBOL_GPL(register_virtio_driver);
	299
	300	void unregister_virtio_driver(struct virtio_driver *driver)
	301	{
	302	driver_unregister(&driver->driver);
	303	}
	304	EXPORT_SYMBOL_GPL(unregister_virtio_driver);
	305
	306	int register_virtio_device(struct virtio_device *dev)
	307	{
	308	int err;
	309
	310	dev->dev.bus = &virtio_bus;
b769f579 RR	311
b769f579 RR	312	/* Assign a unique device index and hence name. */
90e03207 AH	313	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
	314	if (err < 0)
	315	goto out;
	316
	317	dev->index = err;
99e0b6c8	318	dev_set_name(&dev->dev, "virtio%u", dev->index);
ec3d41c4	319
22b7050a MT	320	spin_lock_init(&dev->config_lock);
	321	dev->config_enabled = false;
	322	dev->config_change_pending = false;
	323
6e5aa7ef RR	324	/* We always start by resetting the device, in case a previous
	325	* driver messed it up. This also tests that code path a little. */
	326	dev->config->reset(dev);
	327
ec3d41c4	328	/* Acknowledge that we've seen the device. */
9fe7bfce	329	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
ec3d41c4	330
9499f5e7 RR	331	INIT_LIST_HEAD(&dev->vqs);
9499f5e7 RR	332
ec3d41c4 RR	333	/* device_register() causes the bus infrastructure to look for a
	334	* matching driver. */
	335	err = device_register(&dev->dev);
e60ea67b	336	if (err)
e60ea67b	337	ida_simple_remove(&virtio_index_ida, dev->index);
90e03207	338	out:
ec3d41c4	339	if (err)
9fe7bfce	340	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4 RR	341	return err;
	342	}
	343	EXPORT_SYMBOL_GPL(register_virtio_device);
	344
	345	void unregister_virtio_device(struct virtio_device *dev)
	346	{
237242bd CH	347	int index = dev->index; /* save for after device release */
237242bd CH	348
ec3d41c4	349	device_unregister(&dev->dev);
237242bd	350	ida_simple_remove(&virtio_index_ida, index);
ec3d41c4 RR	351	}
	352	EXPORT_SYMBOL_GPL(unregister_virtio_device);
	353
c6716bae MT	354	#ifdef CONFIG_PM_SLEEP
	355	int virtio_device_freeze(struct virtio_device *dev)
	356	{
	357	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	358
22b7050a MT	359	virtio_config_disable(dev);
22b7050a MT	360
c6716bae MT	361	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
	362
	363	if (drv && drv->freeze)
	364	return drv->freeze(dev);
	365
	366	return 0;
	367	}
	368	EXPORT_SYMBOL_GPL(virtio_device_freeze);
	369
	370	int virtio_device_restore(struct virtio_device *dev)
	371	{
	372	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
5c609a5e	373	int ret;
c6716bae MT	374
	375	/* We always start by resetting the device, in case a previous
	376	* driver messed it up. */
	377	dev->config->reset(dev);
	378
	379	/* Acknowledge that we've seen the device. */
9fe7bfce	380	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
c6716bae MT	381
	382	/* Maybe driver failed before freeze.
	383	* Restore the failed status, for debugging. */
	384	if (dev->failed)
9fe7bfce	385	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
c6716bae MT	386
	387	if (!drv)
	388	return 0;
	389
	390	/* We have a driver! */
9fe7bfce	391	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c6716bae	392
30683a8c	393	ret = virtio_finalize_features(dev);
5c609a5e MT	394	if (ret)
5c609a5e MT	395	goto err;
c6716bae MT	396
c6716bae MT	397	if (drv->restore) {
5c609a5e MT	398	ret = drv->restore(dev);
	399	if (ret)
	400	goto err;
c6716bae MT	401	}
	402
	403	/* Finally, tell the device we're all set */
9fe7bfce	404	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
c6716bae	405
22b7050a MT	406	virtio_config_enable(dev);
22b7050a MT	407
c6716bae	408	return 0;
5c609a5e MT	409
5c609a5e MT	410	err:
9fe7bfce	411	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
5c609a5e	412	return ret;
c6716bae MT	413	}
	414	EXPORT_SYMBOL_GPL(virtio_device_restore);
	415	#endif
	416
ec3d41c4 RR	417	static int virtio_init(void)
	418	{
	419	if (bus_register(&virtio_bus) != 0)
	420	panic("virtio bus registration failed");
	421	return 0;
	422	}
c6fd4701 RR	423
	424	static void __exit virtio_exit(void)
	425	{
	426	bus_unregister(&virtio_bus);
c13f99b7	427	ida_destroy(&virtio_index_ida);
c6fd4701	428	}
ec3d41c4	429	core_initcall(virtio_init);
c6fd4701 RR	430	module_exit(virtio_exit);
	431
	432	MODULE_LICENSE("GPL");