Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 ssize_t modalias_show(struct device *_d,
24 struct device_attribute *attr, char *buf)
25{
26 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
27
28 return sprintf(buf, "virtio:d%08Xv%08X\n",
29 dev->id.device, dev->id.vendor);
30}
31static struct device_attribute virtio_dev_attrs[] = {
32 __ATTR_RO(device),
33 __ATTR_RO(vendor),
34 __ATTR_RO(status),
35 __ATTR_RO(modalias),
36 __ATTR_NULL
37};
38
39static inline int virtio_id_match(const struct virtio_device *dev,
40 const struct virtio_device_id *id)
41{
42 if (id->device != dev->id.device)
43 return 0;
44
45 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor;
46}
47
48/* This looks through all the IDs a driver claims to support. If any of them
49 * match, we return 1 and the kernel will call virtio_dev_probe(). */
50static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
51{
52 unsigned int i;
53 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
54 const struct virtio_device_id *ids;
55
56 ids = container_of(_dr, struct virtio_driver, driver)->id_table;
57 for (i = 0; ids[i].device; i++)
58 if (virtio_id_match(dev, &ids[i]))
59 return 1;
60 return 0;
61}
62
63static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
64{
65 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
66
67 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
68 dev->id.device, dev->id.vendor);
69}
70
71static struct bus_type virtio_bus = {
72 .name = "virtio",
73 .match = virtio_dev_match,
74 .dev_attrs = virtio_dev_attrs,
75 .uevent = virtio_uevent,
76};
77
78static void add_status(struct virtio_device *dev, unsigned status)
79{
80 dev->config->set_status(dev, dev->config->get_status(dev) | status);
81}
82
83void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
84 unsigned int fbit)
85{
86 unsigned int i;
87 struct virtio_driver *drv = container_of(vdev->dev.driver,
88 struct virtio_driver, driver);
89
90 for (i = 0; i < drv->feature_table_size; i++)
91 if (drv->feature_table[i] == fbit)
92 return;
93 BUG();
94}
95EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
96
97static int virtio_dev_probe(struct device *_d)
98{
99 int err, i;
100 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
101 struct virtio_driver *drv = container_of(dev->dev.driver,
102 struct virtio_driver, driver);
103 u32 device_features;
104
105 /* We have a driver! */
106 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
107
108 /* Figure out what features the device supports. */
109 device_features = dev->config->get_features(dev);
110
111 /* Features supported by both device and driver into dev->features. */
112 memset(dev->features, 0, sizeof(dev->features));
113 for (i = 0; i < drv->feature_table_size; i++) {
114 unsigned int f = drv->feature_table[i];
115 BUG_ON(f >= 32);
116 if (device_features & (1 << f))
117 set_bit(f, dev->features);
118 }
119
120 err = drv->probe(dev);
121 if (err)
122 add_status(dev, VIRTIO_CONFIG_S_FAILED);
123 else {
124 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
125 /* They should never have set feature bits beyond 32 */
126 dev->config->set_features(dev, dev->features[0]);
127 }
128 return err;
129}
130
131static int virtio_dev_remove(struct device *_d)
132{
133 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
134 struct virtio_driver *drv = container_of(dev->dev.driver,
135 struct virtio_driver, driver);
136
137 drv->remove(dev);
138
139 /* Driver should have reset device. */
140 BUG_ON(dev->config->get_status(dev));
141
142 /* Acknowledge the device's existence again. */
143 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
144 return 0;
145}
146
147int register_virtio_driver(struct virtio_driver *driver)
148{
149 /* Catch this early. */
150 BUG_ON(driver->feature_table_size && !driver->feature_table);
151 driver->driver.bus = &virtio_bus;
152 driver->driver.probe = virtio_dev_probe;
153 driver->driver.remove = virtio_dev_remove;
154 return driver_register(&driver->driver);
155}
156EXPORT_SYMBOL_GPL(register_virtio_driver);
157
158void unregister_virtio_driver(struct virtio_driver *driver)
159{
160 driver_unregister(&driver->driver);
161}
162EXPORT_SYMBOL_GPL(unregister_virtio_driver);
163
164int register_virtio_device(struct virtio_device *dev)
165{
166 int err;
167
168 dev->dev.bus = &virtio_bus;
169 sprintf(dev->dev.bus_id, "%u", dev->index);
170
171 /* We always start by resetting the device, in case a previous
172 * driver messed it up. This also tests that code path a little. */
173 dev->config->reset(dev);
174
175 /* Acknowledge that we've seen the device. */
176 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
177
178 /* device_register() causes the bus infrastructure to look for a
179 * matching driver. */
180 err = device_register(&dev->dev);
181 if (err)
182 add_status(dev, VIRTIO_CONFIG_S_FAILED);
183 return err;
184}
185EXPORT_SYMBOL_GPL(register_virtio_device);
186
187void unregister_virtio_device(struct virtio_device *dev)
188{
189 device_unregister(&dev->dev);
190}
191EXPORT_SYMBOL_GPL(unregister_virtio_device);
192
193static int virtio_init(void)
194{
195 if (bus_register(&virtio_bus) != 0)
196 panic("virtio bus registration failed");
197 return 0;
198}
199
200static void __exit virtio_exit(void)
201{
202 bus_unregister(&virtio_bus);
203}
204core_initcall(virtio_init);
205module_exit(virtio_exit);
206
207MODULE_LICENSE("GPL");