aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/virtio/virtio.c
blob: f640e0b732b74468a80f58f4618fafe9bdeccc3f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
#include <linux/virtio.h>
#include <linux/spinlock.h>
#include <linux/virtio_config.h>

static ssize_t device_show(struct device *_d,
			   struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
	return sprintf(buf, "%hu", dev->id.device);
}
static ssize_t vendor_show(struct device *_d,
			   struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
	return sprintf(buf, "%hu", dev->id.vendor);
}
static ssize_t status_show(struct device *_d,
			   struct device_attribute *attr, char *buf)
{
	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
	return sprintf(buf, "0x%08x", dev->config->get_status(dev));
}
static struct device_attribute virtio_dev_attrs[] = {
	__ATTR_RO(device),
	__ATTR_RO(vendor),
	__ATTR_RO(status),
	__ATTR_NULL
};

static inline int virtio_id_match(const struct virtio_device *dev,
				  const struct virtio_device_id *id)
{
	if (id->device != dev->id.device)
		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 = container_of(_dv,struct virtio_device,dev);
	const struct virtio_device_id *ids;

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

static struct bus_type virtio_bus = {
	.name  = "virtio",
	.match = virtio_dev_match,
	.dev_attrs = virtio_dev_attrs,
};

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

static int virtio_dev_probe(struct device *_d)
{
	int err;
	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
	struct virtio_driver *drv = container_of(dev->dev.driver,
						 struct virtio_driver, driver);

	add_status(dev, VIRTIO_CONFIG_S_DRIVER);
	err = drv->probe(dev);
	if (err)
		add_status(dev, VIRTIO_CONFIG_S_FAILED);
	else
		add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
	return err;
}

int register_virtio_driver(struct virtio_driver *driver)
{
	driver->driver.bus = &virtio_bus;
	driver->driver.probe = virtio_dev_probe;
	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;
	sprintf(dev->dev.bus_id, "%u", dev->index);

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

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

void unregister_virtio_device(struct virtio_device *dev)
{
	device_unregister(&dev->dev);
}
EXPORT_SYMBOL_GPL(unregister_virtio_device);

int __virtio_config_val(struct virtio_device *vdev,
			u8 type, void *val, size_t size)
{
	void *token;
	unsigned int len;

	token = vdev->config->find(vdev, type, &len);
	if (!token)
		return -ENOENT;

	if (len != size)
		return -EIO;

	vdev->config->get(vdev, token, val, size);
	return 0;
}
EXPORT_SYMBOL_GPL(__virtio_config_val);

int virtio_use_bit(struct virtio_device *vdev,
		   void *token, unsigned int len, unsigned int bitnum)
{
	unsigned long bits[16];

	/* This makes it convenient to pass-through find() results. */
	if (!token)
		return 0;

	/* bit not in range of this bitfield? */
	if (bitnum * 8 >= len / 2)
		return 0;

	/* Giant feature bitfields are silly. */
	BUG_ON(len > sizeof(bits));
	vdev->config->get(vdev, token, bits, len);

	if (!test_bit(bitnum, bits))
		return 0;

	/* Set acknowledge bit, and write it back. */
	set_bit(bitnum + len * 8 / 2, bits);
	vdev->config->set(vdev, token, bits, len);
	return 1;
}
EXPORT_SYMBOL_GPL(virtio_use_bit);

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