[linux-block.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 <linux/of.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);

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);
}

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);

/* Do some validation, then set FEATURES_OK */
static int virtio_features_ok(struct virtio_device *dev)
{
	unsigned status;
	int ret;

	might_sleep();

	ret = arch_has_restricted_virtio_memory_access();
	if (ret) {
		if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
			dev_warn(&dev->dev,
				 "device must provide VIRTIO_F_VERSION_1\n");
			return -ENODEV;
		}

		if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
			dev_warn(&dev->dev,
				 "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
			return -ENODEV;
		}
	}

	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;
}

/**
 * virtio_reset_device - quiesce device for removal
 * @dev: the device to reset
 *
 * Prevents device from sending interrupts and accessing memory.
 *
 * Generally used for cleanup during driver / device removal.
 *
 * Once this has been invoked, caller must ensure that
 * virtqueue_notify / virtqueue_kick are not in progress.
 *
 * Note: this guarantees that vq callbacks are not in progress, however caller
 * is responsible for preventing access from other contexts, such as a system
 * call/workqueue/bh.  Invoking virtio_break_device then flushing any such
 * contexts is one way to handle that.
 * */
void virtio_reset_device(struct virtio_device *dev)
{
	dev->config->reset(dev);
}
EXPORT_SYMBOL_GPL(virtio_reset_device);

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);

	err = dev->config->finalize_features(dev);
	if (err)
		goto err;

	if (drv->validate) {
		u64 features = dev->features;

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

		/* Did validation change any features? Then write them again. */
		if (features != dev->features) {
			err = dev->config->finalize_features(dev);
			if (err)
				goto err;
		}
	}

	err = virtio_features_ok(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 void 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);

	of_node_put(dev->dev.of_node);
}

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);

static int virtio_device_of_init(struct virtio_device *dev)
{
	struct device_node *np, *pnode = dev_of_node(dev->dev.parent);
	char compat[] = "virtio,deviceXXXXXXXX";
	int ret, count;

	if (!pnode)
		return 0;

	count = of_get_available_child_count(pnode);
	if (!count)
		return 0;

	/* There can be only 1 child node */
	if (WARN_ON(count > 1))
		return -EINVAL;

	np = of_get_next_available_child(pnode, NULL);
	if (WARN_ON(!np))
		return -ENODEV;

	ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device);
	BUG_ON(ret >= sizeof(compat));

	/*
	 * On powerpc/pseries virtio devices are PCI devices so PCI
	 * vendor/device ids play the role of the "compatible" property.
	 * Simply don't init of_node in this case.
	 */
	if (!of_device_is_compatible(np, compat)) {
		ret = 0;
		goto out;
	}

	dev->dev.of_node = np;
	return 0;

out:
	of_node_put(np);
	return ret;
}

/**
 * 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);

	err = virtio_device_of_init(dev);
	if (err)
		goto out_ida_remove;

	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);
	spin_lock_init(&dev->vqs_list_lock);

	/*
	 * device_add() causes the bus infrastructure to look for a matching
	 * driver.
	 */
	err = device_add(&dev->dev);
	if (err)
		goto out_of_node_put;

	return 0;

out_of_node_put:
	of_node_put(dev->dev.of_node);
out_ida_remove:
	ida_simple_remove(&virtio_index_ida, dev->index);
out:
	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
	return err;
}
EXPORT_SYMBOL_GPL(register_virtio_device);

bool is_virtio_device(struct device *dev)
{
	return dev->bus == &virtio_bus;
}
EXPORT_SYMBOL_GPL(is_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 = dev->config->finalize_features(dev);
	if (ret)
		goto err;

	ret = virtio_features_ok(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>
694a1116	7	#include <linux/of.h>
b6098c30	8	#include <uapi/linux/virtio_ids.h>
ec3d41c4	9
b769f579	10	/* Unique numbering for virtio devices. */
90e03207	11	static DEFINE_IDA(virtio_index_ida);
b769f579	12
ec3d41c4 RR	13	static ssize_t device_show(struct device *_d,
	14	struct device_attribute attr, char buf)
	15	{
9bffdca8	16	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	17	return sprintf(buf, "0x%04x\n", dev->id.device);
ec3d41c4	18	}
3736dab6 GKH	19	static DEVICE_ATTR_RO(device);
3736dab6 GKH	20
ec3d41c4 RR	21	static ssize_t vendor_show(struct device *_d,
	22	struct device_attribute attr, char buf)
	23	{
9bffdca8	24	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	25	return sprintf(buf, "0x%04x\n", dev->id.vendor);
ec3d41c4	26	}
3736dab6 GKH	27	static DEVICE_ATTR_RO(vendor);
3736dab6 GKH	28
ec3d41c4 RR	29	static ssize_t status_show(struct device *_d,
	30	struct device_attribute attr, char buf)
	31	{
9bffdca8	32	struct virtio_device *dev = dev_to_virtio(_d);
be6528b2	33	return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
ec3d41c4	34	}
3736dab6 GKH	35	static DEVICE_ATTR_RO(status);
3736dab6 GKH	36
b01d9f28 RR	37	static ssize_t modalias_show(struct device *_d,
	38	struct device_attribute attr, char buf)
	39	{
9bffdca8	40	struct virtio_device *dev = dev_to_virtio(_d);
b01d9f28 RR	41	return sprintf(buf, "virtio:d%08Xv%08X\n",
	42	dev->id.device, dev->id.vendor);
	43	}
3736dab6 GKH	44	static DEVICE_ATTR_RO(modalias);
3736dab6 GKH	45
a9289282 RR	46	static ssize_t features_show(struct device *_d,
	47	struct device_attribute attr, char buf)
	48	{
9bffdca8	49	struct virtio_device *dev = dev_to_virtio(_d);
a9289282 RR	50	unsigned int i;
	51	ssize_t len = 0;
	52
	53	/* We actually represent this as a bitstring, as it could be
	54	* arbitrary length in future. */
e16e12be	55	for (i = 0; i < sizeof(dev->features)*8; i++)
a9289282	56	len += sprintf(buf+len, "%c",
e16e12be	57	__virtio_test_bit(dev, i) ? '1' : '0');
a9289282 RR	58	len += sprintf(buf+len, "\n");
	59	return len;
	60	}
3736dab6 GKH	61	static DEVICE_ATTR_RO(features);
	62
	63	static struct attribute *virtio_dev_attrs[] = {
	64	&dev_attr_device.attr,
	65	&dev_attr_vendor.attr,
	66	&dev_attr_status.attr,
	67	&dev_attr_modalias.attr,
	68	&dev_attr_features.attr,
	69	NULL,
ec3d41c4	70	};
3736dab6	71	ATTRIBUTE_GROUPS(virtio_dev);
ec3d41c4 RR	72
	73	static inline int virtio_id_match(const struct virtio_device *dev,
	74	const struct virtio_device_id *id)
	75	{
e3353853	76	if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
ec3d41c4 RR	77	return 0;
ec3d41c4 RR	78
c89e8016	79	return id->vendor == VIRTIO_DEV_ANY_ID \|\| id->vendor == dev->id.vendor;
ec3d41c4 RR	80	}
	81
	82	/* This looks through all the IDs a driver claims to support. If any of them
	83	* match, we return 1 and the kernel will call virtio_dev_probe(). */
	84	static int virtio_dev_match(struct device _dv, struct device_driver _dr)
	85	{
	86	unsigned int i;
9bffdca8	87	struct virtio_device *dev = dev_to_virtio(_dv);
ec3d41c4 RR	88	const struct virtio_device_id *ids;
ec3d41c4 RR	89
9a2bdcc8	90	ids = drv_to_virtio(_dr)->id_table;
ec3d41c4 RR	91	for (i = 0; ids[i].device; i++)
	92	if (virtio_id_match(dev, &ids[i]))
	93	return 1;
	94	return 0;
	95	}
	96
b01d9f28 RR	97	static int virtio_uevent(struct device _dv, struct kobj_uevent_env env)
b01d9f28 RR	98	{
9bffdca8	99	struct virtio_device *dev = dev_to_virtio(_dv);
b01d9f28 RR	100
	101	return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
	102	dev->id.device, dev->id.vendor);
	103	}
	104
c45a6816 RR	105	void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
	106	unsigned int fbit)
	107	{
	108	unsigned int i;
9a2bdcc8	109	struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
c45a6816 RR	110
	111	for (i = 0; i < drv->feature_table_size; i++)
	112	if (drv->feature_table[i] == fbit)
	113	return;
b3bb62d1 MT	114
	115	if (drv->feature_table_legacy) {
	116	for (i = 0; i < drv->feature_table_size_legacy; i++)
	117	if (drv->feature_table_legacy[i] == fbit)
	118	return;
	119	}
	120
c45a6816 RR	121	BUG();
	122	}
	123	EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
	124
22b7050a MT	125	static void __virtio_config_changed(struct virtio_device *dev)
	126	{
	127	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	128
	129	if (!dev->config_enabled)
	130	dev->config_change_pending = true;
	131	else if (drv && drv->config_changed)
	132	drv->config_changed(dev);
	133	}
	134
	135	void virtio_config_changed(struct virtio_device *dev)
	136	{
	137	unsigned long flags;
	138
	139	spin_lock_irqsave(&dev->config_lock, flags);
	140	__virtio_config_changed(dev);
	141	spin_unlock_irqrestore(&dev->config_lock, flags);
	142	}
	143	EXPORT_SYMBOL_GPL(virtio_config_changed);
	144
bc22ed2e	145	static void virtio_config_disable(struct virtio_device *dev)
22b7050a MT	146	{
	147	spin_lock_irq(&dev->config_lock);
	148	dev->config_enabled = false;
	149	spin_unlock_irq(&dev->config_lock);
	150	}
	151
bc22ed2e	152	static 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
	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
4fa59ede MT	169	/* Do some validation, then set FEATURES_OK */
4fa59ede MT	170	static int virtio_features_ok(struct virtio_device *dev)
30683a8c	171	{
30683a8c	172	unsigned status;
4fa59ede	173	int ret;
30683a8c	174
ab7a2375	175	might_sleep();
30683a8c	176
0afa15e1 PM	177	ret = arch_has_restricted_virtio_memory_access();
	178	if (ret) {
	179	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
	180	dev_warn(&dev->dev,
	181	"device must provide VIRTIO_F_VERSION_1\n");
	182	return -ENODEV;
	183	}
	184
	185	if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
	186	dev_warn(&dev->dev,
	187	"device must provide VIRTIO_F_ACCESS_PLATFORM\n");
	188	return -ENODEV;
	189	}
	190	}
	191
30683a8c MT	192	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
	193	return 0;
	194
9fe7bfce	195	virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
30683a8c MT	196	status = dev->config->get_status(dev);
	197	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
	198	dev_err(&dev->dev, "virtio: device refuses features: %x\n",
	199	status);
	200	return -ENODEV;
	201	}
	202	return 0;
	203	}
	204
c46eccda MT	205	/**
	206	* virtio_reset_device - quiesce device for removal
	207	* @dev: the device to reset
	208	*
	209	* Prevents device from sending interrupts and accessing memory.
	210	*
	211	* Generally used for cleanup during driver / device removal.
	212	*
	213	* Once this has been invoked, caller must ensure that
	214	* virtqueue_notify / virtqueue_kick are not in progress.
	215	*
	216	* Note: this guarantees that vq callbacks are not in progress, however caller
	217	* is responsible for preventing access from other contexts, such as a system
	218	* call/workqueue/bh. Invoking virtio_break_device then flushing any such
	219	* contexts is one way to handle that.
	220	* */
d9679d00 MT	221	void virtio_reset_device(struct virtio_device *dev)
	222	{
	223	dev->config->reset(dev);
	224	}
	225	EXPORT_SYMBOL_GPL(virtio_reset_device);
	226
ec3d41c4 RR	227	static int virtio_dev_probe(struct device *_d)
ec3d41c4 RR	228	{
c45a6816	229	int err, i;
9bffdca8	230	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	231	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
d0254773	232	u64 device_features;
c102659d	233	u64 driver_features;
b3bb62d1	234	u64 driver_features_legacy;
ec3d41c4	235
c45a6816	236	/* We have a driver! */
9fe7bfce	237	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c45a6816 RR	238
	239	/* Figure out what features the device supports. */
	240	device_features = dev->config->get_features(dev);
	241
c102659d MT	242	/* Figure out what features the driver supports. */
c102659d MT	243	driver_features = 0;
c45a6816 RR	244	for (i = 0; i < drv->feature_table_size; i++) {
c45a6816 RR	245	unsigned int f = drv->feature_table[i];
d0254773	246	BUG_ON(f >= 64);
c102659d	247	driver_features \|= (1ULL << f);
c45a6816 RR	248	}
c45a6816 RR	249
b3bb62d1 MT	250	/* Some drivers have a separate feature table for virtio v1.0 */
	251	if (drv->feature_table_legacy) {
	252	driver_features_legacy = 0;
	253	for (i = 0; i < drv->feature_table_size_legacy; i++) {
	254	unsigned int f = drv->feature_table_legacy[i];
	255	BUG_ON(f >= 64);
	256	driver_features_legacy \|= (1ULL << f);
	257	}
	258	} else {
	259	driver_features_legacy = driver_features;
	260	}
	261
747ae34a	262	if (device_features & (1ULL << VIRTIO_F_VERSION_1))
b3bb62d1 MT	263	dev->features = driver_features & device_features;
	264	else
	265	dev->features = driver_features_legacy & device_features;
c102659d	266
c624896e	267	/* Transport features always preserved to pass to finalize_features. */
dd7c7bc4	268	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
d0254773	269	if (device_features & (1ULL << i))
e16e12be	270	__virtio_set_bit(dev, i);
dd7c7bc4	271
4fa59ede MT	272	err = dev->config->finalize_features(dev);
	273	if (err)
	274	goto err;
	275
404123c2	276	if (drv->validate) {
4fa59ede MT	277	u64 features = dev->features;
4fa59ede MT	278
404123c2 MT	279	err = drv->validate(dev);
	280	if (err)
	281	goto err;
4fa59ede MT	282
	283	/* Did validation change any features? Then write them again. */
	284	if (features != dev->features) {
	285	err = dev->config->finalize_features(dev);
	286	if (err)
	287	goto err;
	288	}
404123c2 MT	289	}
404123c2 MT	290
4fa59ede	291	err = virtio_features_ok(dev);
5c609a5e MT	292	if (err)
5c609a5e MT	293	goto err;
ef688e15	294
ec3d41c4 RR	295	err = drv->probe(dev);
ec3d41c4 RR	296	if (err)
cb3f6d9d	297	goto err;
22b7050a	298
5b40a7da RR	299	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
	300	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
	301	virtio_device_ready(dev);
	302
cb3f6d9d MT	303	if (drv->scan)
cb3f6d9d MT	304	drv->scan(dev);
ef688e15	305
cb3f6d9d MT	306	virtio_config_enable(dev);
	307
	308	return 0;
	309	err:
9fe7bfce	310	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4	311	return err;
cb3f6d9d	312
ec3d41c4 RR	313	}
ec3d41c4 RR	314
fc7a6209	315	static void virtio_dev_remove(struct device *_d)
74b2553f	316	{
9bffdca8	317	struct virtio_device *dev = dev_to_virtio(_d);
9a2bdcc8	318	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
74b2553f	319
22b7050a MT	320	virtio_config_disable(dev);
22b7050a MT	321
74b2553f	322	drv->remove(dev);
6e5aa7ef RR	323
6e5aa7ef RR	324	/* Driver should have reset device. */
5543a6ac	325	WARN_ON_ONCE(dev->config->get_status(dev));
6e5aa7ef RR	326
6e5aa7ef RR	327	/* Acknowledge the device's existence again. */
9fe7bfce	328	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
694a1116 VK	329
694a1116 VK	330	of_node_put(dev->dev.of_node);
74b2553f RR	331	}
74b2553f RR	332
e962fa66 MM	333	static struct bus_type virtio_bus = {
	334	.name = "virtio",
	335	.match = virtio_dev_match,
3736dab6	336	.dev_groups = virtio_dev_groups,
e962fa66 MM	337	.uevent = virtio_uevent,
	338	.probe = virtio_dev_probe,
	339	.remove = virtio_dev_remove,
	340	};
	341
ec3d41c4 RR	342	int register_virtio_driver(struct virtio_driver *driver)
ec3d41c4 RR	343	{
c45a6816 RR	344	/* Catch this early. */
c45a6816 RR	345	BUG_ON(driver->feature_table_size && !driver->feature_table);
ec3d41c4	346	driver->driver.bus = &virtio_bus;
ec3d41c4 RR	347	return driver_register(&driver->driver);
	348	}
	349	EXPORT_SYMBOL_GPL(register_virtio_driver);
	350
	351	void unregister_virtio_driver(struct virtio_driver *driver)
	352	{
	353	driver_unregister(&driver->driver);
	354	}
	355	EXPORT_SYMBOL_GPL(unregister_virtio_driver);
	356
694a1116 VK	357	static int virtio_device_of_init(struct virtio_device *dev)
	358	{
	359	struct device_node np, pnode = dev_of_node(dev->dev.parent);
	360	char compat[] = "virtio,deviceXXXXXXXX";
	361	int ret, count;
	362
	363	if (!pnode)
	364	return 0;
	365
	366	count = of_get_available_child_count(pnode);
	367	if (!count)
	368	return 0;
	369
	370	/* There can be only 1 child node */
	371	if (WARN_ON(count > 1))
	372	return -EINVAL;
	373
	374	np = of_get_next_available_child(pnode, NULL);
	375	if (WARN_ON(!np))
	376	return -ENODEV;
	377
	378	ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device);
	379	BUG_ON(ret >= sizeof(compat));
	380
0d818706 MT	381	/*
	382	* On powerpc/pseries virtio devices are PCI devices so PCI
	383	* vendor/device ids play the role of the "compatible" property.
	384	* Simply don't init of_node in this case.
	385	*/
694a1116	386	if (!of_device_is_compatible(np, compat)) {
0d818706	387	ret = 0;
694a1116 VK	388	goto out;
	389	}
	390
	391	dev->dev.of_node = np;
	392	return 0;
	393
	394	out:
	395	of_node_put(np);
	396	return ret;
	397	}
	398
f2b44cde	399	/**
	400	* register_virtio_device - register virtio device
	401	* @dev : virtio device to be registered
	402	*
	403	* On error, the caller must call put_device on &@dev->dev (and not kfree),
	404	* as another code path may have obtained a reference to @dev.
	405	*
	406	* Returns: 0 on suceess, -error on failure
	407	*/
ec3d41c4 RR	408	int register_virtio_device(struct virtio_device *dev)
	409	{
	410	int err;
	411
	412	dev->dev.bus = &virtio_bus;
f2b44cde	413	device_initialize(&dev->dev);
b769f579 RR	414
b769f579 RR	415	/* Assign a unique device index and hence name. */
90e03207 AH	416	err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
	417	if (err < 0)
	418	goto out;
	419
	420	dev->index = err;
99e0b6c8	421	dev_set_name(&dev->dev, "virtio%u", dev->index);
ec3d41c4	422
694a1116 VK	423	err = virtio_device_of_init(dev);
	424	if (err)
	425	goto out_ida_remove;
	426
22b7050a MT	427	spin_lock_init(&dev->config_lock);
	428	dev->config_enabled = false;
	429	dev->config_change_pending = false;
	430
6e5aa7ef RR	431	/* We always start by resetting the device, in case a previous
	432	* driver messed it up. This also tests that code path a little. */
	433	dev->config->reset(dev);
	434
ec3d41c4	435	/* Acknowledge that we've seen the device. */
9fe7bfce	436	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
ec3d41c4	437
9499f5e7	438	INIT_LIST_HEAD(&dev->vqs);
0e566c8f	439	spin_lock_init(&dev->vqs_list_lock);
9499f5e7	440
f2b44cde	441	/*
	442	* device_add() causes the bus infrastructure to look for a matching
	443	* driver.
	444	*/
	445	err = device_add(&dev->dev);
e60ea67b	446	if (err)
694a1116 VK	447	goto out_of_node_put;
	448
	449	return 0;
	450
	451	out_of_node_put:
	452	of_node_put(dev->dev.of_node);
	453	out_ida_remove:
	454	ida_simple_remove(&virtio_index_ida, dev->index);
90e03207	455	out:
694a1116	456	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
ec3d41c4 RR	457	return err;
	458	}
	459	EXPORT_SYMBOL_GPL(register_virtio_device);
	460
a0308938 DS	461	bool is_virtio_device(struct device *dev)
	462	{
	463	return dev->bus == &virtio_bus;
	464	}
	465	EXPORT_SYMBOL_GPL(is_virtio_device);
	466
ec3d41c4 RR	467	void unregister_virtio_device(struct virtio_device *dev)
ec3d41c4 RR	468	{
237242bd CH	469	int index = dev->index; /* save for after device release */
237242bd CH	470
ec3d41c4	471	device_unregister(&dev->dev);
237242bd	472	ida_simple_remove(&virtio_index_ida, index);
ec3d41c4 RR	473	}
	474	EXPORT_SYMBOL_GPL(unregister_virtio_device);
	475
c6716bae MT	476	#ifdef CONFIG_PM_SLEEP
	477	int virtio_device_freeze(struct virtio_device *dev)
	478	{
	479	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
	480
22b7050a MT	481	virtio_config_disable(dev);
22b7050a MT	482
c6716bae MT	483	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
	484
	485	if (drv && drv->freeze)
	486	return drv->freeze(dev);
	487
	488	return 0;
	489	}
	490	EXPORT_SYMBOL_GPL(virtio_device_freeze);
	491
	492	int virtio_device_restore(struct virtio_device *dev)
	493	{
	494	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
5c609a5e	495	int ret;
c6716bae MT	496
	497	/* We always start by resetting the device, in case a previous
	498	* driver messed it up. */
	499	dev->config->reset(dev);
	500
	501	/* Acknowledge that we've seen the device. */
9fe7bfce	502	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
c6716bae MT	503
	504	/* Maybe driver failed before freeze.
	505	* Restore the failed status, for debugging. */
	506	if (dev->failed)
9fe7bfce	507	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
c6716bae MT	508
	509	if (!drv)
	510	return 0;
	511
	512	/* We have a driver! */
9fe7bfce	513	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
c6716bae	514
4fa59ede MT	515	ret = dev->config->finalize_features(dev);
	516	if (ret)
	517	goto err;
	518
	519	ret = virtio_features_ok(dev);
5c609a5e MT	520	if (ret)
5c609a5e MT	521	goto err;
c6716bae MT	522
c6716bae MT	523	if (drv->restore) {
5c609a5e MT	524	ret = drv->restore(dev);
	525	if (ret)
	526	goto err;
c6716bae MT	527	}
c6716bae MT	528
7414539c MT	529	/* Finally, tell the device we're all set */
7414539c MT	530	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
c6716bae	531
22b7050a MT	532	virtio_config_enable(dev);
22b7050a MT	533
c6716bae	534	return 0;
5c609a5e MT	535
5c609a5e MT	536	err:
9fe7bfce	537	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
5c609a5e	538	return ret;
c6716bae MT	539	}
	540	EXPORT_SYMBOL_GPL(virtio_device_restore);
	541	#endif
	542
ec3d41c4 RR	543	static int virtio_init(void)
	544	{
	545	if (bus_register(&virtio_bus) != 0)
	546	panic("virtio bus registration failed");
	547	return 0;
	548	}
c6fd4701 RR	549
	550	static void __exit virtio_exit(void)
	551	{
	552	bus_unregister(&virtio_bus);
c13f99b7	553	ida_destroy(&virtio_index_ida);
c6fd4701	554	}
ec3d41c4	555	core_initcall(virtio_init);
c6fd4701 RR	556	module_exit(virtio_exit);
	557
	558	MODULE_LICENSE("GPL");