[mirror_ubuntu-jammy-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)
{
	might_sleep();
	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;

	might_sleep();
	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);

/**
 * register_virtio_device - register virtio device
 * @dev        : virtio device to be registered
 *
 * On error, the caller must call put_device on &@dev->dev (and not kfree),
 * as another code path may have obtained a reference to @dev.
 *
 * Returns: 0 on suceess, -error on failure
 */
int register_virtio_device(struct virtio_device *dev)
{
	int err;

	dev->dev.bus = &virtio_bus;
	device_initialize(&dev->dev);

	/* 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_add() causes the bus infrastructure to look for a matching
	 * driver.
	 */
	err = device_add(&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	{
ab7a2375	164	might_sleep();
9fe7bfce JF	165	dev->config->set_status(dev, dev->config->get_status(dev) \| status);
	166	}
	167	EXPORT_SYMBOL_GPL(virtio_add_status);
22b7050a	168
9fe7bfce	169	int virtio_finalize_features(struct virtio_device *dev)
30683a8c MT	170	{
	171	int ret = dev->config->finalize_features(dev);
	172	unsigned status;
	173
ab7a2375	174	might_sleep();
30683a8c MT	175	if (ret)
	176	return ret;
	177
	178	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
	179	return 0;
	180
9fe7bfce	181	virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
30683a8c MT	182	status = dev->config->get_status(dev);
	183	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
	184	dev_err(&dev->dev, "virtio: device refuses features: %x\n",
	185	status);
	186	return -ENODEV;
	187	}
	188	return 0;
	189	}
9fe7bfce	190	EXPORT_SYMBOL_GPL(virtio_finalize_features);
30683a8c	191
ec3d41c4 RR	192	static int virtio_dev_probe(struct device *_d)
ec3d41c4 RR	193	{
c45a6816	194	int err, i;
9bffdca8	195	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	196	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
d0254773	197	u64 device_features;
c102659d	198	u64 driver_features;
b3bb62d1	199	u64 driver_features_legacy;
ec3d41c4	200
c45a6816	201	/* We have a driver! */
9fe7bfce	202	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c45a6816 RR	203
	204	/* Figure out what features the device supports. */
	205	device_features = dev->config->get_features(dev);
	206
c102659d MT	207	/* Figure out what features the driver supports. */
c102659d MT	208	driver_features = 0;
c45a6816 RR	209	for (i = 0; i < drv->feature_table_size; i++) {
c45a6816 RR	210	unsigned int f = drv->feature_table[i];
d0254773	211	BUG_ON(f >= 64);
c102659d	212	driver_features \|= (1ULL << f);
c45a6816 RR	213	}
c45a6816 RR	214
b3bb62d1 MT	215	/* Some drivers have a separate feature table for virtio v1.0 */
	216	if (drv->feature_table_legacy) {
	217	driver_features_legacy = 0;
	218	for (i = 0; i < drv->feature_table_size_legacy; i++) {
	219	unsigned int f = drv->feature_table_legacy[i];
	220	BUG_ON(f >= 64);
	221	driver_features_legacy \|= (1ULL << f);
	222	}
	223	} else {
	224	driver_features_legacy = driver_features;
	225	}
	226
747ae34a	227	if (device_features & (1ULL << VIRTIO_F_VERSION_1))
b3bb62d1 MT	228	dev->features = driver_features & device_features;
	229	else
	230	dev->features = driver_features_legacy & device_features;
c102659d	231
c624896e	232	/* Transport features always preserved to pass to finalize_features. */
dd7c7bc4	233	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
d0254773	234	if (device_features & (1ULL << i))
e16e12be	235	__virtio_set_bit(dev, i);
dd7c7bc4	236
404123c2 MT	237	if (drv->validate) {
	238	err = drv->validate(dev);
	239	if (err)
	240	goto err;
	241	}
	242
30683a8c	243	err = virtio_finalize_features(dev);
5c609a5e MT	244	if (err)
5c609a5e MT	245	goto err;
ef688e15	246
ec3d41c4 RR	247	err = drv->probe(dev);
ec3d41c4 RR	248	if (err)
cb3f6d9d	249	goto err;
22b7050a	250
5b40a7da RR	251	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
	252	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
	253	virtio_device_ready(dev);
	254
cb3f6d9d MT	255	if (drv->scan)
cb3f6d9d MT	256	drv->scan(dev);
ef688e15	257
cb3f6d9d MT	258	virtio_config_enable(dev);
	259
	260	return 0;
	261	err:
9fe7bfce	262	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4	263	return err;
cb3f6d9d	264
ec3d41c4 RR	265	}
ec3d41c4 RR	266
74b2553f RR	267	static int virtio_dev_remove(struct device *_d)
74b2553f RR	268	{
9bffdca8	269	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	270	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
74b2553f	271
22b7050a MT	272	virtio_config_disable(dev);
22b7050a MT	273
74b2553f	274	drv->remove(dev);
6e5aa7ef RR	275
6e5aa7ef RR	276	/* Driver should have reset device. */
5543a6ac	277	WARN_ON_ONCE(dev->config->get_status(dev));
6e5aa7ef RR	278
6e5aa7ef RR	279	/* Acknowledge the device's existence again. */
9fe7bfce	280	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
74b2553f RR	281	return 0;
	282	}
	283
e962fa66 MM	284	static struct bus_type virtio_bus = {
	285	.name = "virtio",
	286	.match = virtio_dev_match,
3736dab6	287	.dev_groups = virtio_dev_groups,
e962fa66 MM	288	.uevent = virtio_uevent,
	289	.probe = virtio_dev_probe,
	290	.remove = virtio_dev_remove,
	291	};
	292
ec3d41c4 RR	293	int register_virtio_driver(struct virtio_driver *driver)
ec3d41c4 RR	294	{
c45a6816 RR	295	/* Catch this early. */
c45a6816 RR	296	BUG_ON(driver->feature_table_size && !driver->feature_table);
ec3d41c4	297	driver->driver.bus = &virtio_bus;
ec3d41c4 RR	298	return driver_register(&driver->driver);
	299	}
	300	EXPORT_SYMBOL_GPL(register_virtio_driver);
	301
	302	void unregister_virtio_driver(struct virtio_driver *driver)
	303	{
	304	driver_unregister(&driver->driver);
	305	}
	306	EXPORT_SYMBOL_GPL(unregister_virtio_driver);
	307
f2b44cde	308	/**
	309	* register_virtio_device - register virtio device
	310	* @dev : virtio device to be registered
	311	*
	312	* On error, the caller must call put_device on &@dev->dev (and not kfree),
	313	* as another code path may have obtained a reference to @dev.
	314	*
	315	* Returns: 0 on suceess, -error on failure
	316	*/
ec3d41c4 RR	317	int register_virtio_device(struct virtio_device *dev)
	318	{
	319	int err;
	320
	321	dev->dev.bus = &virtio_bus;
f2b44cde	322	device_initialize(&dev->dev);
b769f579 RR	323
b769f579 RR	324	/* Assign a unique device index and hence name. */
90e03207 AH	325	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
	326	if (err < 0)
	327	goto out;
	328
	329	dev->index = err;
99e0b6c8	330	dev_set_name(&dev->dev, "virtio%u", dev->index);
ec3d41c4	331
22b7050a MT	332	spin_lock_init(&dev->config_lock);
	333	dev->config_enabled = false;
	334	dev->config_change_pending = false;
	335
6e5aa7ef RR	336	/* We always start by resetting the device, in case a previous
	337	* driver messed it up. This also tests that code path a little. */
	338	dev->config->reset(dev);
	339
ec3d41c4	340	/* Acknowledge that we've seen the device. */
9fe7bfce	341	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
ec3d41c4	342
9499f5e7 RR	343	INIT_LIST_HEAD(&dev->vqs);
9499f5e7 RR	344
f2b44cde	345	/*
	346	* device_add() causes the bus infrastructure to look for a matching
	347	* driver.
	348	*/
	349	err = device_add(&dev->dev);
e60ea67b	350	if (err)
e60ea67b	351	ida_simple_remove(&virtio_index_ida, dev->index);
90e03207	352	out:
ec3d41c4	353	if (err)
9fe7bfce	354	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4 RR	355	return err;
	356	}
	357	EXPORT_SYMBOL_GPL(register_virtio_device);
	358
	359	void unregister_virtio_device(struct virtio_device *dev)
	360	{
237242bd CH	361	int index = dev->index; /* save for after device release */
237242bd CH	362
ec3d41c4	363	device_unregister(&dev->dev);
237242bd	364	ida_simple_remove(&virtio_index_ida, index);
ec3d41c4 RR	365	}
	366	EXPORT_SYMBOL_GPL(unregister_virtio_device);
	367
c6716bae MT	368	#ifdef CONFIG_PM_SLEEP
	369	int virtio_device_freeze(struct virtio_device *dev)
	370	{
	371	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	372
22b7050a MT	373	virtio_config_disable(dev);
22b7050a MT	374
c6716bae MT	375	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
	376
	377	if (drv && drv->freeze)
	378	return drv->freeze(dev);
	379
	380	return 0;
	381	}
	382	EXPORT_SYMBOL_GPL(virtio_device_freeze);
	383
	384	int virtio_device_restore(struct virtio_device *dev)
	385	{
	386	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
5c609a5e	387	int ret;
c6716bae MT	388
	389	/* We always start by resetting the device, in case a previous
	390	* driver messed it up. */
	391	dev->config->reset(dev);
	392
	393	/* Acknowledge that we've seen the device. */
9fe7bfce	394	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
c6716bae MT	395
	396	/* Maybe driver failed before freeze.
	397	* Restore the failed status, for debugging. */
	398	if (dev->failed)
9fe7bfce	399	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
c6716bae MT	400
	401	if (!drv)
	402	return 0;
	403
	404	/* We have a driver! */
9fe7bfce	405	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c6716bae	406
30683a8c	407	ret = virtio_finalize_features(dev);
5c609a5e MT	408	if (ret)
5c609a5e MT	409	goto err;
c6716bae MT	410
c6716bae MT	411	if (drv->restore) {
5c609a5e MT	412	ret = drv->restore(dev);
	413	if (ret)
	414	goto err;
c6716bae MT	415	}
	416
	417	/* Finally, tell the device we're all set */
9fe7bfce	418	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
c6716bae	419
22b7050a MT	420	virtio_config_enable(dev);
22b7050a MT	421
c6716bae	422	return 0;
5c609a5e MT	423
5c609a5e MT	424	err:
9fe7bfce	425	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
5c609a5e	426	return ret;
c6716bae MT	427	}
	428	EXPORT_SYMBOL_GPL(virtio_device_restore);
	429	#endif
	430
ec3d41c4 RR	431	static int virtio_init(void)
	432	{
	433	if (bus_register(&virtio_bus) != 0)
	434	panic("virtio bus registration failed");
	435	return 0;
	436	}
c6fd4701 RR	437
	438	static void __exit virtio_exit(void)
	439	{
	440	bus_unregister(&virtio_bus);
c13f99b7	441	ida_destroy(&virtio_index_ida);
c6fd4701	442	}
ec3d41c4	443	core_initcall(virtio_init);
c6fd4701 RR	444	module_exit(virtio_exit);
	445
	446	MODULE_LICENSE("GPL");