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1 | #include <linux/virtio.h> |
2 | #include <linux/spinlock.h> |
3 | #include <linux/virtio_config.h> |
4 | #include <linux/module.h> |
5 | #include <linux/idr.h> |
6 | |
7 | /* Unique numbering for virtio devices. */ |
8 | static DEFINE_IDA(virtio_index_ida); |
9 | |
10 | static ssize_t device_show(struct device *_d, |
11 | struct device_attribute *attr, char *buf) |
12 | { |
13 | struct virtio_device *dev = dev_to_virtio(_d); |
14 | return sprintf(buf, "0x%04x\n", dev->id.device); |
15 | } |
16 | static ssize_t vendor_show(struct device *_d, |
17 | struct device_attribute *attr, char *buf) |
18 | { |
19 | struct virtio_device *dev = dev_to_virtio(_d); |
20 | return sprintf(buf, "0x%04x\n", dev->id.vendor); |
21 | } |
22 | static ssize_t status_show(struct device *_d, |
23 | struct device_attribute *attr, char *buf) |
24 | { |
25 | struct virtio_device *dev = dev_to_virtio(_d); |
26 | return sprintf(buf, "0x%08x\n", dev->config->get_status(dev)); |
27 | } |
28 | static ssize_t modalias_show(struct device *_d, |
29 | struct device_attribute *attr, char *buf) |
30 | { |
31 | struct virtio_device *dev = dev_to_virtio(_d); |
32 | return sprintf(buf, "virtio:d%08Xv%08X\n", |
33 | dev->id.device, dev->id.vendor); |
34 | } |
35 | static ssize_t features_show(struct device *_d, |
36 | struct device_attribute *attr, char *buf) |
37 | { |
38 | struct virtio_device *dev = dev_to_virtio(_d); |
39 | unsigned int i; |
40 | ssize_t len = 0; |
41 | |
42 | /* We actually represent this as a bitstring, as it could be |
43 | * arbitrary length in future. */ |
44 | for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++) |
45 | len += sprintf(buf+len, "%c", |
46 | test_bit(i, dev->features) ? '1' : '0'); |
47 | len += sprintf(buf+len, "\n"); |
48 | return len; |
49 | } |
50 | static struct device_attribute virtio_dev_attrs[] = { |
51 | __ATTR_RO(device), |
52 | __ATTR_RO(vendor), |
53 | __ATTR_RO(status), |
54 | __ATTR_RO(modalias), |
55 | __ATTR_RO(features), |
56 | __ATTR_NULL |
57 | }; |
58 | |
59 | static inline int virtio_id_match(const struct virtio_device *dev, |
60 | const struct virtio_device_id *id) |
61 | { |
62 | if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID) |
63 | return 0; |
64 | |
65 | return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor; |
66 | } |
67 | |
68 | /* This looks through all the IDs a driver claims to support. If any of them |
69 | * match, we return 1 and the kernel will call virtio_dev_probe(). */ |
70 | static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) |
71 | { |
72 | unsigned int i; |
73 | struct virtio_device *dev = dev_to_virtio(_dv); |
74 | const struct virtio_device_id *ids; |
75 | |
76 | ids = drv_to_virtio(_dr)->id_table; |
77 | for (i = 0; ids[i].device; i++) |
78 | if (virtio_id_match(dev, &ids[i])) |
79 | return 1; |
80 | return 0; |
81 | } |
82 | |
83 | static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) |
84 | { |
85 | struct virtio_device *dev = dev_to_virtio(_dv); |
86 | |
87 | return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X", |
88 | dev->id.device, dev->id.vendor); |
89 | } |
90 | |
91 | static void add_status(struct virtio_device *dev, unsigned status) |
92 | { |
93 | dev->config->set_status(dev, dev->config->get_status(dev) | status); |
94 | } |
95 | |
96 | void virtio_check_driver_offered_feature(const struct virtio_device *vdev, |
97 | unsigned int fbit) |
98 | { |
99 | unsigned int i; |
100 | struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver); |
101 | |
102 | for (i = 0; i < drv->feature_table_size; i++) |
103 | if (drv->feature_table[i] == fbit) |
104 | return; |
105 | BUG(); |
106 | } |
107 | EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); |
108 | |
109 | static int virtio_dev_probe(struct device *_d) |
110 | { |
111 | int err, i; |
112 | struct virtio_device *dev = dev_to_virtio(_d); |
113 | struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); |
114 | u32 device_features; |
115 | |
116 | /* We have a driver! */ |
117 | add_status(dev, VIRTIO_CONFIG_S_DRIVER); |
118 | |
119 | /* Figure out what features the device supports. */ |
120 | device_features = dev->config->get_features(dev); |
121 | |
122 | /* Features supported by both device and driver into dev->features. */ |
123 | memset(dev->features, 0, sizeof(dev->features)); |
124 | for (i = 0; i < drv->feature_table_size; i++) { |
125 | unsigned int f = drv->feature_table[i]; |
126 | BUG_ON(f >= 32); |
127 | if (device_features & (1 << f)) |
128 | set_bit(f, dev->features); |
129 | } |
130 | |
131 | /* Transport features always preserved to pass to finalize_features. */ |
132 | for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) |
133 | if (device_features & (1 << i)) |
134 | set_bit(i, dev->features); |
135 | |
136 | dev->config->finalize_features(dev); |
137 | |
138 | err = drv->probe(dev); |
139 | if (err) |
140 | add_status(dev, VIRTIO_CONFIG_S_FAILED); |
141 | else { |
142 | add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); |
143 | if (drv->scan) |
144 | drv->scan(dev); |
145 | } |
146 | |
147 | return err; |
148 | } |
149 | |
150 | static int virtio_dev_remove(struct device *_d) |
151 | { |
152 | struct virtio_device *dev = dev_to_virtio(_d); |
153 | struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); |
154 | |
155 | drv->remove(dev); |
156 | |
157 | /* Driver should have reset device. */ |
158 | WARN_ON_ONCE(dev->config->get_status(dev)); |
159 | |
160 | /* Acknowledge the device's existence again. */ |
161 | add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); |
162 | return 0; |
163 | } |
164 | |
165 | static struct bus_type virtio_bus = { |
166 | .name = "virtio", |
167 | .match = virtio_dev_match, |
168 | .dev_attrs = virtio_dev_attrs, |
169 | .uevent = virtio_uevent, |
170 | .probe = virtio_dev_probe, |
171 | .remove = virtio_dev_remove, |
172 | }; |
173 | |
174 | int register_virtio_driver(struct virtio_driver *driver) |
175 | { |
176 | /* Catch this early. */ |
177 | BUG_ON(driver->feature_table_size && !driver->feature_table); |
178 | driver->driver.bus = &virtio_bus; |
179 | return driver_register(&driver->driver); |
180 | } |
181 | EXPORT_SYMBOL_GPL(register_virtio_driver); |
182 | |
183 | void unregister_virtio_driver(struct virtio_driver *driver) |
184 | { |
185 | driver_unregister(&driver->driver); |
186 | } |
187 | EXPORT_SYMBOL_GPL(unregister_virtio_driver); |
188 | |
189 | int register_virtio_device(struct virtio_device *dev) |
190 | { |
191 | int err; |
192 | |
193 | dev->dev.bus = &virtio_bus; |
194 | |
195 | /* Assign a unique device index and hence name. */ |
196 | err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL); |
197 | if (err < 0) |
198 | goto out; |
199 | |
200 | dev->index = err; |
201 | dev_set_name(&dev->dev, "virtio%u", dev->index); |
202 | |
203 | /* We always start by resetting the device, in case a previous |
204 | * driver messed it up. This also tests that code path a little. */ |
205 | dev->config->reset(dev); |
206 | |
207 | /* Acknowledge that we've seen the device. */ |
208 | add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); |
209 | |
210 | INIT_LIST_HEAD(&dev->vqs); |
211 | |
212 | /* device_register() causes the bus infrastructure to look for a |
213 | * matching driver. */ |
214 | err = device_register(&dev->dev); |
215 | out: |
216 | if (err) |
217 | add_status(dev, VIRTIO_CONFIG_S_FAILED); |
218 | return err; |
219 | } |
220 | EXPORT_SYMBOL_GPL(register_virtio_device); |
221 | |
222 | void unregister_virtio_device(struct virtio_device *dev) |
223 | { |
224 | int index = dev->index; /* save for after device release */ |
225 | |
226 | device_unregister(&dev->dev); |
227 | ida_simple_remove(&virtio_index_ida, index); |
228 | } |
229 | EXPORT_SYMBOL_GPL(unregister_virtio_device); |
230 | |
231 | static int virtio_init(void) |
232 | { |
233 | if (bus_register(&virtio_bus) != 0) |
234 | panic("virtio bus registration failed"); |
235 | return 0; |
236 | } |
237 | |
238 | static void __exit virtio_exit(void) |
239 | { |
240 | bus_unregister(&virtio_bus); |
241 | } |
242 | core_initcall(virtio_init); |
243 | module_exit(virtio_exit); |
244 | |
245 | MODULE_LICENSE("GPL"); |
246 |
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