[mirror_ubuntu-hirsute-kernel.git] / drivers / virtio / virtio.c

// SPDX-License-Identifier: GPL-2.0-only
#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
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
ec3d41c4 RR	2	#include <linux/virtio.h>
	3	#include <linux/spinlock.h>
	4	#include <linux/virtio_config.h>
b5a2c4f1	5	#include <linux/module.h>
90e03207	6	#include <linux/idr.h>
b6098c30	7	#include <uapi/linux/virtio_ids.h>
ec3d41c4	8
b769f579	9	/* Unique numbering for virtio devices. */
90e03207	10	static DEFINE_IDA(virtio_index_ida);
b769f579	11
ec3d41c4 RR	12	static ssize_t device_show(struct device *_d,
	13	struct device_attribute attr, char buf)
	14	{
9bffdca8	15	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	16	return sprintf(buf, "0x%04x\n", dev->id.device);
ec3d41c4	17	}
3736dab6 GKH	18	static DEVICE_ATTR_RO(device);
3736dab6 GKH	19
ec3d41c4 RR	20	static ssize_t vendor_show(struct device *_d,
	21	struct device_attribute attr, char buf)
	22	{
9bffdca8	23	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	24	return sprintf(buf, "0x%04x\n", dev->id.vendor);
ec3d41c4	25	}
3736dab6 GKH	26	static DEVICE_ATTR_RO(vendor);
3736dab6 GKH	27
ec3d41c4 RR	28	static ssize_t status_show(struct device *_d,
	29	struct device_attribute attr, char buf)
	30	{
9bffdca8	31	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	32	return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
ec3d41c4	33	}
3736dab6 GKH	34	static DEVICE_ATTR_RO(status);
3736dab6 GKH	35
b01d9f28 RR	36	static ssize_t modalias_show(struct device *_d,
	37	struct device_attribute attr, char buf)
	38	{
9bffdca8	39	struct virtio_device *dev = dev_to_virtio(_d);
b01d9f28 RR	40	return sprintf(buf, "virtio:d%08Xv%08X\n",
	41	dev->id.device, dev->id.vendor);
	42	}
3736dab6 GKH	43	static DEVICE_ATTR_RO(modalias);
3736dab6 GKH	44
a9289282 RR	45	static ssize_t features_show(struct device *_d,
	46	struct device_attribute attr, char buf)
	47	{
9bffdca8	48	struct virtio_device *dev = dev_to_virtio(_d);
a9289282 RR	49	unsigned int i;
	50	ssize_t len = 0;
	51
	52	/* We actually represent this as a bitstring, as it could be
	53	* arbitrary length in future. */
e16e12be	54	for (i = 0; i < sizeof(dev->features)*8; i++)
a9289282	55	len += sprintf(buf+len, "%c",
e16e12be	56	__virtio_test_bit(dev, i) ? '1' : '0');
a9289282 RR	57	len += sprintf(buf+len, "\n");
	58	return len;
	59	}
3736dab6 GKH	60	static DEVICE_ATTR_RO(features);
	61
	62	static struct attribute *virtio_dev_attrs[] = {
	63	&dev_attr_device.attr,
	64	&dev_attr_vendor.attr,
	65	&dev_attr_status.attr,
	66	&dev_attr_modalias.attr,
	67	&dev_attr_features.attr,
	68	NULL,
ec3d41c4	69	};
3736dab6	70	ATTRIBUTE_GROUPS(virtio_dev);
ec3d41c4 RR	71
	72	static inline int virtio_id_match(const struct virtio_device *dev,
	73	const struct virtio_device_id *id)
	74	{
e3353853	75	if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
ec3d41c4 RR	76	return 0;
ec3d41c4 RR	77
c89e8016	78	return id->vendor == VIRTIO_DEV_ANY_ID \|\| id->vendor == dev->id.vendor;
ec3d41c4 RR	79	}
	80
	81	/* This looks through all the IDs a driver claims to support. If any of them
	82	* match, we return 1 and the kernel will call virtio_dev_probe(). */
	83	static int virtio_dev_match(struct device _dv, struct device_driver _dr)
	84	{
	85	unsigned int i;
9bffdca8	86	struct virtio_device *dev = dev_to_virtio(_dv);
ec3d41c4 RR	87	const struct virtio_device_id *ids;
ec3d41c4 RR	88
9a2bdcc8	89	ids = drv_to_virtio(_dr)->id_table;
ec3d41c4 RR	90	for (i = 0; ids[i].device; i++)
	91	if (virtio_id_match(dev, &ids[i]))
	92	return 1;
	93	return 0;
	94	}
	95
b01d9f28 RR	96	static int virtio_uevent(struct device _dv, struct kobj_uevent_env env)
b01d9f28 RR	97	{
9bffdca8	98	struct virtio_device *dev = dev_to_virtio(_dv);
b01d9f28 RR	99
	100	return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
	101	dev->id.device, dev->id.vendor);
	102	}
	103
c45a6816 RR	104	void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
	105	unsigned int fbit)
	106	{
	107	unsigned int i;
9a2bdcc8	108	struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
c45a6816 RR	109
	110	for (i = 0; i < drv->feature_table_size; i++)
	111	if (drv->feature_table[i] == fbit)
	112	return;
b3bb62d1 MT	113
	114	if (drv->feature_table_legacy) {
	115	for (i = 0; i < drv->feature_table_size_legacy; i++)
	116	if (drv->feature_table_legacy[i] == fbit)
	117	return;
	118	}
	119
c45a6816 RR	120	BUG();
	121	}
	122	EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
	123
22b7050a MT	124	static void __virtio_config_changed(struct virtio_device *dev)
	125	{
	126	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	127
	128	if (!dev->config_enabled)
	129	dev->config_change_pending = true;
	130	else if (drv && drv->config_changed)
	131	drv->config_changed(dev);
	132	}
	133
	134	void virtio_config_changed(struct virtio_device *dev)
	135	{
	136	unsigned long flags;
	137
	138	spin_lock_irqsave(&dev->config_lock, flags);
	139	__virtio_config_changed(dev);
	140	spin_unlock_irqrestore(&dev->config_lock, flags);
	141	}
	142	EXPORT_SYMBOL_GPL(virtio_config_changed);
	143
9fe7bfce	144	void virtio_config_disable(struct virtio_device *dev)
22b7050a MT	145	{
	146	spin_lock_irq(&dev->config_lock);
	147	dev->config_enabled = false;
	148	spin_unlock_irq(&dev->config_lock);
	149	}
9fe7bfce	150	EXPORT_SYMBOL_GPL(virtio_config_disable);
22b7050a	151
9fe7bfce	152	void virtio_config_enable(struct virtio_device *dev)
22b7050a MT	153	{
	154	spin_lock_irq(&dev->config_lock);
	155	dev->config_enabled = true;
	156	if (dev->config_change_pending)
	157	__virtio_config_changed(dev);
	158	dev->config_change_pending = false;
	159	spin_unlock_irq(&dev->config_lock);
	160	}
9fe7bfce JF	161	EXPORT_SYMBOL_GPL(virtio_config_enable);
	162
	163	void virtio_add_status(struct virtio_device *dev, unsigned int status)
	164	{
ab7a2375	165	might_sleep();
9fe7bfce JF	166	dev->config->set_status(dev, dev->config->get_status(dev) \| status);
	167	}
	168	EXPORT_SYMBOL_GPL(virtio_add_status);
22b7050a	169
9fe7bfce	170	int virtio_finalize_features(struct virtio_device *dev)
30683a8c MT	171	{
	172	int ret = dev->config->finalize_features(dev);
	173	unsigned status;
	174
ab7a2375	175	might_sleep();
30683a8c MT	176	if (ret)
	177	return ret;
	178
	179	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
	180	return 0;
	181
9fe7bfce	182	virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
30683a8c MT	183	status = dev->config->get_status(dev);
	184	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
	185	dev_err(&dev->dev, "virtio: device refuses features: %x\n",
	186	status);
	187	return -ENODEV;
	188	}
	189	return 0;
	190	}
9fe7bfce	191	EXPORT_SYMBOL_GPL(virtio_finalize_features);
30683a8c	192
ec3d41c4 RR	193	static int virtio_dev_probe(struct device *_d)
ec3d41c4 RR	194	{
c45a6816	195	int err, i;
9bffdca8	196	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	197	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
d0254773	198	u64 device_features;
c102659d	199	u64 driver_features;
b3bb62d1	200	u64 driver_features_legacy;
ec3d41c4	201
c45a6816	202	/* We have a driver! */
9fe7bfce	203	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c45a6816 RR	204
	205	/* Figure out what features the device supports. */
	206	device_features = dev->config->get_features(dev);
	207
c102659d MT	208	/* Figure out what features the driver supports. */
c102659d MT	209	driver_features = 0;
c45a6816 RR	210	for (i = 0; i < drv->feature_table_size; i++) {
c45a6816 RR	211	unsigned int f = drv->feature_table[i];
d0254773	212	BUG_ON(f >= 64);
c102659d	213	driver_features \|= (1ULL << f);
c45a6816 RR	214	}
c45a6816 RR	215
b3bb62d1 MT	216	/* Some drivers have a separate feature table for virtio v1.0 */
	217	if (drv->feature_table_legacy) {
	218	driver_features_legacy = 0;
	219	for (i = 0; i < drv->feature_table_size_legacy; i++) {
	220	unsigned int f = drv->feature_table_legacy[i];
	221	BUG_ON(f >= 64);
	222	driver_features_legacy \|= (1ULL << f);
	223	}
	224	} else {
	225	driver_features_legacy = driver_features;
	226	}
	227
747ae34a	228	if (device_features & (1ULL << VIRTIO_F_VERSION_1))
b3bb62d1 MT	229	dev->features = driver_features & device_features;
	230	else
	231	dev->features = driver_features_legacy & device_features;
c102659d	232
c624896e	233	/* Transport features always preserved to pass to finalize_features. */
dd7c7bc4	234	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
d0254773	235	if (device_features & (1ULL << i))
e16e12be	236	__virtio_set_bit(dev, i);
dd7c7bc4	237
404123c2 MT	238	if (drv->validate) {
	239	err = drv->validate(dev);
	240	if (err)
	241	goto err;
	242	}
	243
30683a8c	244	err = virtio_finalize_features(dev);
5c609a5e MT	245	if (err)
5c609a5e MT	246	goto err;
ef688e15	247
ec3d41c4 RR	248	err = drv->probe(dev);
ec3d41c4 RR	249	if (err)
cb3f6d9d	250	goto err;
22b7050a	251
5b40a7da RR	252	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
	253	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
	254	virtio_device_ready(dev);
	255
cb3f6d9d MT	256	if (drv->scan)
cb3f6d9d MT	257	drv->scan(dev);
ef688e15	258
cb3f6d9d MT	259	virtio_config_enable(dev);
	260
	261	return 0;
	262	err:
9fe7bfce	263	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4	264	return err;
cb3f6d9d	265
ec3d41c4 RR	266	}
ec3d41c4 RR	267
74b2553f RR	268	static int virtio_dev_remove(struct device *_d)
74b2553f RR	269	{
9bffdca8	270	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	271	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
74b2553f	272
22b7050a MT	273	virtio_config_disable(dev);
22b7050a MT	274
74b2553f	275	drv->remove(dev);
6e5aa7ef RR	276
6e5aa7ef RR	277	/* Driver should have reset device. */
5543a6ac	278	WARN_ON_ONCE(dev->config->get_status(dev));
6e5aa7ef RR	279
6e5aa7ef RR	280	/* Acknowledge the device's existence again. */
9fe7bfce	281	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
74b2553f RR	282	return 0;
	283	}
	284
e962fa66 MM	285	static struct bus_type virtio_bus = {
	286	.name = "virtio",
	287	.match = virtio_dev_match,
3736dab6	288	.dev_groups = virtio_dev_groups,
e962fa66 MM	289	.uevent = virtio_uevent,
	290	.probe = virtio_dev_probe,
	291	.remove = virtio_dev_remove,
	292	};
	293
ec3d41c4 RR	294	int register_virtio_driver(struct virtio_driver *driver)
ec3d41c4 RR	295	{
c45a6816 RR	296	/* Catch this early. */
c45a6816 RR	297	BUG_ON(driver->feature_table_size && !driver->feature_table);
ec3d41c4	298	driver->driver.bus = &virtio_bus;
ec3d41c4 RR	299	return driver_register(&driver->driver);
	300	}
	301	EXPORT_SYMBOL_GPL(register_virtio_driver);
	302
	303	void unregister_virtio_driver(struct virtio_driver *driver)
	304	{
	305	driver_unregister(&driver->driver);
	306	}
	307	EXPORT_SYMBOL_GPL(unregister_virtio_driver);
	308
f2b44cde	309	/**
	310	* register_virtio_device - register virtio device
	311	* @dev : virtio device to be registered
	312	*
	313	* On error, the caller must call put_device on &@dev->dev (and not kfree),
	314	* as another code path may have obtained a reference to @dev.
	315	*
	316	* Returns: 0 on suceess, -error on failure
	317	*/
ec3d41c4 RR	318	int register_virtio_device(struct virtio_device *dev)
	319	{
	320	int err;
	321
	322	dev->dev.bus = &virtio_bus;
f2b44cde	323	device_initialize(&dev->dev);
b769f579 RR	324
b769f579 RR	325	/* Assign a unique device index and hence name. */
90e03207 AH	326	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
	327	if (err < 0)
	328	goto out;
	329
	330	dev->index = err;
99e0b6c8	331	dev_set_name(&dev->dev, "virtio%u", dev->index);
ec3d41c4	332
22b7050a MT	333	spin_lock_init(&dev->config_lock);
	334	dev->config_enabled = false;
	335	dev->config_change_pending = false;
	336
6e5aa7ef RR	337	/* We always start by resetting the device, in case a previous
	338	* driver messed it up. This also tests that code path a little. */
	339	dev->config->reset(dev);
	340
ec3d41c4	341	/* Acknowledge that we've seen the device. */
9fe7bfce	342	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
ec3d41c4	343
9499f5e7 RR	344	INIT_LIST_HEAD(&dev->vqs);
9499f5e7 RR	345
f2b44cde	346	/*
	347	* device_add() causes the bus infrastructure to look for a matching
	348	* driver.
	349	*/
	350	err = device_add(&dev->dev);
e60ea67b	351	if (err)
e60ea67b	352	ida_simple_remove(&virtio_index_ida, dev->index);
90e03207	353	out:
ec3d41c4	354	if (err)
9fe7bfce	355	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4 RR	356	return err;
	357	}
	358	EXPORT_SYMBOL_GPL(register_virtio_device);
	359
	360	void unregister_virtio_device(struct virtio_device *dev)
	361	{
237242bd CH	362	int index = dev->index; /* save for after device release */
237242bd CH	363
ec3d41c4	364	device_unregister(&dev->dev);
237242bd	365	ida_simple_remove(&virtio_index_ida, index);
ec3d41c4 RR	366	}
	367	EXPORT_SYMBOL_GPL(unregister_virtio_device);
	368
c6716bae MT	369	#ifdef CONFIG_PM_SLEEP
	370	int virtio_device_freeze(struct virtio_device *dev)
	371	{
	372	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	373
22b7050a MT	374	virtio_config_disable(dev);
22b7050a MT	375
c6716bae MT	376	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
	377
	378	if (drv && drv->freeze)
	379	return drv->freeze(dev);
	380
	381	return 0;
	382	}
	383	EXPORT_SYMBOL_GPL(virtio_device_freeze);
	384
	385	int virtio_device_restore(struct virtio_device *dev)
	386	{
	387	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
5c609a5e	388	int ret;
c6716bae MT	389
	390	/* We always start by resetting the device, in case a previous
	391	* driver messed it up. */
	392	dev->config->reset(dev);
	393
	394	/* Acknowledge that we've seen the device. */
9fe7bfce	395	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
c6716bae MT	396
	397	/* Maybe driver failed before freeze.
	398	* Restore the failed status, for debugging. */
	399	if (dev->failed)
9fe7bfce	400	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
c6716bae MT	401
	402	if (!drv)
	403	return 0;
	404
	405	/* We have a driver! */
9fe7bfce	406	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c6716bae	407
30683a8c	408	ret = virtio_finalize_features(dev);
5c609a5e MT	409	if (ret)
5c609a5e MT	410	goto err;
c6716bae MT	411
c6716bae MT	412	if (drv->restore) {
5c609a5e MT	413	ret = drv->restore(dev);
	414	if (ret)
	415	goto err;
c6716bae MT	416	}
	417
	418	/* Finally, tell the device we're all set */
9fe7bfce	419	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
c6716bae	420
22b7050a MT	421	virtio_config_enable(dev);
22b7050a MT	422
c6716bae	423	return 0;
5c609a5e MT	424
5c609a5e MT	425	err:
9fe7bfce	426	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
5c609a5e	427	return ret;
c6716bae MT	428	}
	429	EXPORT_SYMBOL_GPL(virtio_device_restore);
	430	#endif
	431
ec3d41c4 RR	432	static int virtio_init(void)
	433	{
	434	if (bus_register(&virtio_bus) != 0)
	435	panic("virtio bus registration failed");
	436	return 0;
	437	}
c6fd4701 RR	438
	439	static void __exit virtio_exit(void)
	440	{
	441	bus_unregister(&virtio_bus);
c13f99b7	442	ida_destroy(&virtio_index_ida);
c6fd4701	443	}
ec3d41c4	444	core_initcall(virtio_init);
c6fd4701 RR	445	module_exit(virtio_exit);
	446
	447	MODULE_LICENSE("GPL");