aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/virtio/virtio.c
diff options
context:
space:
mode:
authorRusty Russell <rusty@rustcorp.com.au>2007-10-21 21:03:36 -0400
committerRusty Russell <rusty@rustcorp.com.au>2007-10-23 01:49:54 -0400
commitec3d41c4db4c21164332826ea8d812f94f2f6886 (patch)
tree9b947e900745cfcc4df7409c6ba5583428964215 /drivers/virtio/virtio.c
parent47436aa4ad054c1c7c8231618e86ebd9305308dc (diff)
Virtio interface
This attempts to implement a "virtual I/O" layer which should allow common drivers to be efficiently used across most virtual I/O mechanisms. It will no-doubt need further enhancement. The virtio drivers add buffers to virtio queues; as the buffers are consumed the driver "interrupt" callbacks are invoked. There is also a generic implementation of config space which drivers can query to get setup information from the host. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Dor Laor <dor.laor@qumranet.com> Cc: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'drivers/virtio/virtio.c')
-rw-r--r--drivers/virtio/virtio.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
new file mode 100644
index 000000000000..f640e0b732b7
--- /dev/null
+++ b/drivers/virtio/virtio.c
@@ -0,0 +1,171 @@
1#include <linux/virtio.h>
2#include <linux/spinlock.h>
3#include <linux/virtio_config.h>
4
5static ssize_t device_show(struct device *_d,
6 struct device_attribute *attr, char *buf)
7{
8 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
9 return sprintf(buf, "%hu", dev->id.device);
10}
11static ssize_t vendor_show(struct device *_d,
12 struct device_attribute *attr, char *buf)
13{
14 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
15 return sprintf(buf, "%hu", dev->id.vendor);
16}
17static ssize_t status_show(struct device *_d,
18 struct device_attribute *attr, char *buf)
19{
20 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
21 return sprintf(buf, "0x%08x", dev->config->get_status(dev));
22}
23static struct device_attribute virtio_dev_attrs[] = {
24 __ATTR_RO(device),
25 __ATTR_RO(vendor),
26 __ATTR_RO(status),
27 __ATTR_NULL
28};
29
30static inline int virtio_id_match(const struct virtio_device *dev,
31 const struct virtio_device_id *id)
32{
33 if (id->device != dev->id.device)
34 return 0;
35
36 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor;
37}
38
39/* This looks through all the IDs a driver claims to support. If any of them
40 * match, we return 1 and the kernel will call virtio_dev_probe(). */
41static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
42{
43 unsigned int i;
44 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
45 const struct virtio_device_id *ids;
46
47 ids = container_of(_dr, struct virtio_driver, driver)->id_table;
48 for (i = 0; ids[i].device; i++)
49 if (virtio_id_match(dev, &ids[i]))
50 return 1;
51 return 0;
52}
53
54static struct bus_type virtio_bus = {
55 .name = "virtio",
56 .match = virtio_dev_match,
57 .dev_attrs = virtio_dev_attrs,
58};
59
60static void add_status(struct virtio_device *dev, unsigned status)
61{
62 dev->config->set_status(dev, dev->config->get_status(dev) | status);
63}
64
65static int virtio_dev_probe(struct device *_d)
66{
67 int err;
68 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
69 struct virtio_driver *drv = container_of(dev->dev.driver,
70 struct virtio_driver, driver);
71
72 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
73 err = drv->probe(dev);
74 if (err)
75 add_status(dev, VIRTIO_CONFIG_S_FAILED);
76 else
77 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
78 return err;
79}
80
81int register_virtio_driver(struct virtio_driver *driver)
82{
83 driver->driver.bus = &virtio_bus;
84 driver->driver.probe = virtio_dev_probe;
85 return driver_register(&driver->driver);
86}
87EXPORT_SYMBOL_GPL(register_virtio_driver);
88
89void unregister_virtio_driver(struct virtio_driver *driver)
90{
91 driver_unregister(&driver->driver);
92}
93EXPORT_SYMBOL_GPL(unregister_virtio_driver);
94
95int register_virtio_device(struct virtio_device *dev)
96{
97 int err;
98
99 dev->dev.bus = &virtio_bus;
100 sprintf(dev->dev.bus_id, "%u", dev->index);
101
102 /* Acknowledge that we've seen the device. */
103 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
104
105 /* device_register() causes the bus infrastructure to look for a
106 * matching driver. */
107 err = device_register(&dev->dev);
108 if (err)
109 add_status(dev, VIRTIO_CONFIG_S_FAILED);
110 return err;
111}
112EXPORT_SYMBOL_GPL(register_virtio_device);
113
114void unregister_virtio_device(struct virtio_device *dev)
115{
116 device_unregister(&dev->dev);
117}
118EXPORT_SYMBOL_GPL(unregister_virtio_device);
119
120int __virtio_config_val(struct virtio_device *vdev,
121 u8 type, void *val, size_t size)
122{
123 void *token;
124 unsigned int len;
125
126 token = vdev->config->find(vdev, type, &len);
127 if (!token)
128 return -ENOENT;
129
130 if (len != size)
131 return -EIO;
132
133 vdev->config->get(vdev, token, val, size);
134 return 0;
135}
136EXPORT_SYMBOL_GPL(__virtio_config_val);
137
138int virtio_use_bit(struct virtio_device *vdev,
139 void *token, unsigned int len, unsigned int bitnum)
140{
141 unsigned long bits[16];
142
143 /* This makes it convenient to pass-through find() results. */
144 if (!token)
145 return 0;
146
147 /* bit not in range of this bitfield? */
148 if (bitnum * 8 >= len / 2)
149 return 0;
150
151 /* Giant feature bitfields are silly. */
152 BUG_ON(len > sizeof(bits));
153 vdev->config->get(vdev, token, bits, len);
154
155 if (!test_bit(bitnum, bits))
156 return 0;
157
158 /* Set acknowledge bit, and write it back. */
159 set_bit(bitnum + len * 8 / 2, bits);
160 vdev->config->set(vdev, token, bits, len);
161 return 1;
162}
163EXPORT_SYMBOL_GPL(virtio_use_bit);
164
165static int virtio_init(void)
166{
167 if (bus_register(&virtio_bus) != 0)
168 panic("virtio bus registration failed");
169 return 0;
170}
171core_initcall(virtio_init);