tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <linux/virtio.h>
2#include <linux/spinlock.h>
3#include <linux/virtio_config.h>
4
5/* Unique numbering for virtio devices. */
6static unsigned int dev_index;
7
8static ssize_t device_show(struct device *_d,
9 struct device_attribute *attr, char *buf)
10{
11 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
12 return sprintf(buf, "%hu", dev->id.device);
13}
14static ssize_t vendor_show(struct device *_d,
15 struct device_attribute *attr, char *buf)
16{
17 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
18 return sprintf(buf, "%hu", dev->id.vendor);
19}
20static ssize_t status_show(struct device *_d,
21 struct device_attribute *attr, char *buf)
22{
23 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
24 return sprintf(buf, "0x%08x", dev->config->get_status(dev));
25}
26static ssize_t modalias_show(struct device *_d,
27 struct device_attribute *attr, char *buf)
28{
29 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
30
31 return sprintf(buf, "virtio:d%08Xv%08X\n",
32 dev->id.device, dev->id.vendor);
33}
34static struct device_attribute virtio_dev_attrs[] = {
35 __ATTR_RO(device),
36 __ATTR_RO(vendor),
37 __ATTR_RO(status),
38 __ATTR_RO(modalias),
39 __ATTR_NULL
40};
41
42static inline int virtio_id_match(const struct virtio_device *dev,
43 const struct virtio_device_id *id)
44{
45 if (id->device != dev->id.device)
46 return 0;
47
48 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor;
49}
50
51/* This looks through all the IDs a driver claims to support. If any of them
52 * match, we return 1 and the kernel will call virtio_dev_probe(). */
53static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
54{
55 unsigned int i;
56 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
57 const struct virtio_device_id *ids;
58
59 ids = container_of(_dr, struct virtio_driver, driver)->id_table;
60 for (i = 0; ids[i].device; i++)
61 if (virtio_id_match(dev, &ids[i]))
62 return 1;
63 return 0;
64}
65
66static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
67{
68 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
69
70 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
71 dev->id.device, dev->id.vendor);
72}
73
74static void add_status(struct virtio_device *dev, unsigned status)
75{
76 dev->config->set_status(dev, dev->config->get_status(dev) | status);
77}
78
79void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
80 unsigned int fbit)
81{
82 unsigned int i;
83 struct virtio_driver *drv = container_of(vdev->dev.driver,
84 struct virtio_driver, driver);
85
86 for (i = 0; i < drv->feature_table_size; i++)
87 if (drv->feature_table[i] == fbit)
88 return;
89 BUG();
90}
91EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
92
93static int virtio_dev_probe(struct device *_d)
94{
95 int err, i;
96 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
97 struct virtio_driver *drv = container_of(dev->dev.driver,
98 struct virtio_driver, driver);
99 u32 device_features;
100
101 /* We have a driver! */
102 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
103
104 /* Figure out what features the device supports. */
105 device_features = dev->config->get_features(dev);
106
107 /* Features supported by both device and driver into dev->features. */
108 memset(dev->features, 0, sizeof(dev->features));
109 for (i = 0; i < drv->feature_table_size; i++) {
110 unsigned int f = drv->feature_table[i];
111 BUG_ON(f >= 32);
112 if (device_features & (1 << f))
113 set_bit(f, dev->features);
114 }
115
116 /* Transport features always preserved to pass to finalize_features. */
117 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
118 if (device_features & (1 << i))
119 set_bit(i, dev->features);
120
121 err = drv->probe(dev);
122 if (err)
123 add_status(dev, VIRTIO_CONFIG_S_FAILED);
124 else {
125 dev->config->finalize_features(dev);
126 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
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
147static struct bus_type virtio_bus = {
148 .name = "virtio",
149 .match = virtio_dev_match,
150 .dev_attrs = virtio_dev_attrs,
151 .uevent = virtio_uevent,
152 .probe = virtio_dev_probe,
153 .remove = virtio_dev_remove,
154};
155
156int register_virtio_driver(struct virtio_driver *driver)
157{
158 /* Catch this early. */
159 BUG_ON(driver->feature_table_size && !driver->feature_table);
160 driver->driver.bus = &virtio_bus;
161 return driver_register(&driver->driver);
162}
163EXPORT_SYMBOL_GPL(register_virtio_driver);
164
165void unregister_virtio_driver(struct virtio_driver *driver)
166{
167 driver_unregister(&driver->driver);
168}
169EXPORT_SYMBOL_GPL(unregister_virtio_driver);
170
171int register_virtio_device(struct virtio_device *dev)
172{
173 int err;
174
175 dev->dev.bus = &virtio_bus;
176
177 /* Assign a unique device index and hence name. */
178 dev->index = dev_index++;
179 sprintf(dev->dev.bus_id, "virtio%u", dev->index);
180
181 /* We always start by resetting the device, in case a previous
182 * driver messed it up. This also tests that code path a little. */
183 dev->config->reset(dev);
184
185 /* Acknowledge that we've seen the device. */
186 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
187
188 /* device_register() causes the bus infrastructure to look for a
189 * matching driver. */
190 err = device_register(&dev->dev);
191 if (err)
192 add_status(dev, VIRTIO_CONFIG_S_FAILED);
193 return err;
194}
195EXPORT_SYMBOL_GPL(register_virtio_device);
196
197void unregister_virtio_device(struct virtio_device *dev)
198{
199 device_unregister(&dev->dev);
200}
201EXPORT_SYMBOL_GPL(unregister_virtio_device);
202
203static int virtio_init(void)
204{
205 if (bus_register(&virtio_bus) != 0)
206 panic("virtio bus registration failed");
207 return 0;
208}
209
210static void __exit virtio_exit(void)
211{
212 bus_unregister(&virtio_bus);
213}
214core_initcall(virtio_init);
215module_exit(virtio_exit);
216
217MODULE_LICENSE("GPL");