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virtio: add virtio 1.0 feature bit
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1#ifndef _LINUX_VIRTIO_CONFIG_H
2#define _LINUX_VIRTIO_CONFIG_H
b4f68be6 3
d2a7ddda 4#include <linux/err.h>
187f1882 5#include <linux/bug.h>
72e61eb4 6#include <linux/virtio.h>
607ca46e 7#include <uapi/linux/virtio_config.h>
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8
9/**
10 * virtio_config_ops - operations for configuring a virtio device
a586d4f6 11 * @get: read the value of a configuration field
ec3d41c4 12 * vdev: the virtio_device
a586d4f6 13 * offset: the offset of the configuration field
ec3d41c4 14 * buf: the buffer to write the field value into.
a586d4f6 15 * len: the length of the buffer
a586d4f6 16 * @set: write the value of a configuration field
ec3d41c4 17 * vdev: the virtio_device
a586d4f6 18 * offset: the offset of the configuration field
ec3d41c4 19 * buf: the buffer to read the field value from.
a586d4f6 20 * len: the length of the buffer
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21 * @get_status: read the status byte
22 * vdev: the virtio_device
23 * Returns the status byte
24 * @set_status: write the status byte
25 * vdev: the virtio_device
26 * status: the new status byte
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27 * @reset: reset the device
28 * vdev: the virtio device
29 * After this, status and feature negotiation must be done again
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30 * Device must not be reset from its vq/config callbacks, or in
31 * parallel with being added/removed.
d2a7ddda 32 * @find_vqs: find virtqueues and instantiate them.
ec3d41c4 33 * vdev: the virtio_device
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34 * nvqs: the number of virtqueues to find
35 * vqs: on success, includes new virtqueues
36 * callbacks: array of callbacks, for each virtqueue
6457f126 37 * include a NULL entry for vqs that do not need a callback
d2a7ddda 38 * names: array of virtqueue names (mainly for debugging)
6457f126 39 * include a NULL entry for vqs unused by driver
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40 * Returns 0 on success or error status
41 * @del_vqs: free virtqueues found by find_vqs().
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42 * @get_features: get the array of feature bits for this device.
43 * vdev: the virtio_device
44 * Returns the first 32 feature bits (all we currently need).
c624896e 45 * @finalize_features: confirm what device features we'll be using.
c45a6816 46 * vdev: the virtio_device
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47 * This gives the final feature bits for the device: it can change
48 * the dev->feature bits if it wants.
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49 * @bus_name: return the bus name associated with the device
50 * vdev: the virtio_device
51 * This returns a pointer to the bus name a la pci_name from which
52 * the caller can then copy.
75a0a52b 53 * @set_vq_affinity: set the affinity for a virtqueue.
ec3d41c4 54 */
d2a7ddda 55typedef void vq_callback_t(struct virtqueue *);
1842f23c 56struct virtio_config_ops {
a586d4f6 57 void (*get)(struct virtio_device *vdev, unsigned offset,
ec3d41c4 58 void *buf, unsigned len);
a586d4f6 59 void (*set)(struct virtio_device *vdev, unsigned offset,
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60 const void *buf, unsigned len);
61 u8 (*get_status)(struct virtio_device *vdev);
62 void (*set_status)(struct virtio_device *vdev, u8 status);
6e5aa7ef 63 void (*reset)(struct virtio_device *vdev);
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64 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
65 struct virtqueue *vqs[],
66 vq_callback_t *callbacks[],
67 const char *names[]);
68 void (*del_vqs)(struct virtio_device *);
d0254773 69 u64 (*get_features)(struct virtio_device *vdev);
c624896e 70 void (*finalize_features)(struct virtio_device *vdev);
66846048 71 const char *(*bus_name)(struct virtio_device *vdev);
75a0a52b 72 int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
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73};
74
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75/* If driver didn't advertise the feature, it will never appear. */
76void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
77 unsigned int fbit);
78
79/**
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80 * __virtio_test_bit - helper to test feature bits. For use by transports.
81 * Devices should normally use virtio_has_feature,
82 * which includes more checks.
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83 * @vdev: the device
84 * @fbit: the feature bit
85 */
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86static inline bool __virtio_test_bit(const struct virtio_device *vdev,
87 unsigned int fbit)
88{
89 /* Did you forget to fix assumptions on max features? */
90 if (__builtin_constant_p(fbit))
d0254773 91 BUILD_BUG_ON(fbit >= 64);
d4024af5 92 else
d0254773 93 BUG_ON(fbit >= 64);
d4024af5 94
d0254773 95 return vdev->features & BIT_ULL(fbit);
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96}
97
98/**
99 * __virtio_set_bit - helper to set feature bits. For use by transports.
100 * @vdev: the device
101 * @fbit: the feature bit
102 */
103static inline void __virtio_set_bit(struct virtio_device *vdev,
104 unsigned int fbit)
105{
106 /* Did you forget to fix assumptions on max features? */
107 if (__builtin_constant_p(fbit))
d0254773 108 BUILD_BUG_ON(fbit >= 64);
d4024af5 109 else
d0254773 110 BUG_ON(fbit >= 64);
d4024af5 111
d0254773 112 vdev->features |= BIT_ULL(fbit);
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113}
114
115/**
116 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
117 * @vdev: the device
118 * @fbit: the feature bit
119 */
120static inline void __virtio_clear_bit(struct virtio_device *vdev,
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121 unsigned int fbit)
122{
123 /* Did you forget to fix assumptions on max features? */
1765e3a4 124 if (__builtin_constant_p(fbit))
d0254773 125 BUILD_BUG_ON(fbit >= 64);
1765e3a4 126 else
d0254773 127 BUG_ON(fbit >= 64);
c45a6816 128
d0254773 129 vdev->features &= ~BIT_ULL(fbit);
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130}
131
132/**
133 * virtio_has_feature - helper to determine if this device has this feature.
134 * @vdev: the device
135 * @fbit: the feature bit
136 */
137static inline bool virtio_has_feature(const struct virtio_device *vdev,
138 unsigned int fbit)
139{
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140 if (fbit < VIRTIO_TRANSPORT_F_START)
141 virtio_check_driver_offered_feature(vdev, fbit);
142
d4024af5 143 return __virtio_test_bit(vdev, fbit);
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144}
145
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146static inline
147struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
148 vq_callback_t *c, const char *n)
149{
150 vq_callback_t *callbacks[] = { c };
151 const char *names[] = { n };
152 struct virtqueue *vq;
153 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
154 if (err < 0)
155 return ERR_PTR(err);
156 return vq;
157}
66846048 158
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159/**
160 * virtio_device_ready - enable vq use in probe function
161 * @vdev: the device
162 *
163 * Driver must call this to use vqs in the probe function.
164 *
165 * Note: vqs are enabled automatically after probe returns.
166 */
167static inline
168void virtio_device_ready(struct virtio_device *dev)
169{
170 unsigned status = dev->config->get_status(dev);
171
172 BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
173 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
174}
175
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176static inline
177const char *virtio_bus_name(struct virtio_device *vdev)
178{
179 if (!vdev->config->bus_name)
180 return "virtio";
181 return vdev->config->bus_name(vdev);
182}
183
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184/**
185 * virtqueue_set_affinity - setting affinity for a virtqueue
186 * @vq: the virtqueue
187 * @cpu: the cpu no.
188 *
189 * Pay attention the function are best-effort: the affinity hint may not be set
190 * due to config support, irq type and sharing.
191 *
192 */
193static inline
194int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
195{
196 struct virtio_device *vdev = vq->vdev;
197 if (vdev->config->set_vq_affinity)
198 return vdev->config->set_vq_affinity(vq, cpu);
199 return 0;
200}
201
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202/* Config space accessors. */
203#define virtio_cread(vdev, structname, member, ptr) \
204 do { \
205 /* Must match the member's type, and be integer */ \
206 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
207 (*ptr) = 1; \
208 \
209 switch (sizeof(*ptr)) { \
210 case 1: \
211 *(ptr) = virtio_cread8(vdev, \
212 offsetof(structname, member)); \
213 break; \
214 case 2: \
215 *(ptr) = virtio_cread16(vdev, \
216 offsetof(structname, member)); \
217 break; \
218 case 4: \
219 *(ptr) = virtio_cread32(vdev, \
220 offsetof(structname, member)); \
221 break; \
222 case 8: \
223 *(ptr) = virtio_cread64(vdev, \
224 offsetof(structname, member)); \
225 break; \
226 default: \
227 BUG(); \
228 } \
229 } while(0)
230
231/* Config space accessors. */
232#define virtio_cwrite(vdev, structname, member, ptr) \
233 do { \
234 /* Must match the member's type, and be integer */ \
235 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
236 BUG_ON((*ptr) == 1); \
237 \
238 switch (sizeof(*ptr)) { \
239 case 1: \
240 virtio_cwrite8(vdev, \
241 offsetof(structname, member), \
242 *(ptr)); \
243 break; \
244 case 2: \
245 virtio_cwrite16(vdev, \
246 offsetof(structname, member), \
247 *(ptr)); \
248 break; \
249 case 4: \
250 virtio_cwrite32(vdev, \
251 offsetof(structname, member), \
252 *(ptr)); \
253 break; \
254 case 8: \
255 virtio_cwrite64(vdev, \
256 offsetof(structname, member), \
257 *(ptr)); \
258 break; \
259 default: \
260 BUG(); \
261 } \
262 } while(0)
263
264static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
265{
266 u8 ret;
267 vdev->config->get(vdev, offset, &ret, sizeof(ret));
268 return ret;
269}
270
271static inline void virtio_cread_bytes(struct virtio_device *vdev,
272 unsigned int offset,
273 void *buf, size_t len)
274{
275 vdev->config->get(vdev, offset, buf, len);
276}
277
278static inline void virtio_cwrite8(struct virtio_device *vdev,
279 unsigned int offset, u8 val)
280{
281 vdev->config->set(vdev, offset, &val, sizeof(val));
282}
283
284static inline u16 virtio_cread16(struct virtio_device *vdev,
285 unsigned int offset)
286{
287 u16 ret;
288 vdev->config->get(vdev, offset, &ret, sizeof(ret));
289 return ret;
290}
291
292static inline void virtio_cwrite16(struct virtio_device *vdev,
293 unsigned int offset, u16 val)
294{
295 vdev->config->set(vdev, offset, &val, sizeof(val));
296}
297
298static inline u32 virtio_cread32(struct virtio_device *vdev,
299 unsigned int offset)
300{
301 u32 ret;
302 vdev->config->get(vdev, offset, &ret, sizeof(ret));
303 return ret;
304}
305
306static inline void virtio_cwrite32(struct virtio_device *vdev,
307 unsigned int offset, u32 val)
308{
309 vdev->config->set(vdev, offset, &val, sizeof(val));
310}
311
312static inline u64 virtio_cread64(struct virtio_device *vdev,
313 unsigned int offset)
314{
315 u64 ret;
316 vdev->config->get(vdev, offset, &ret, sizeof(ret));
317 return ret;
318}
319
320static inline void virtio_cwrite64(struct virtio_device *vdev,
321 unsigned int offset, u64 val)
322{
323 vdev->config->set(vdev, offset, &val, sizeof(val));
324}
325
326/* Conditional config space accessors. */
327#define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
328 ({ \
329 int _r = 0; \
330 if (!virtio_has_feature(vdev, fbit)) \
331 _r = -ENOENT; \
332 else \
333 virtio_cread((vdev), structname, member, ptr); \
334 _r; \
335 })
75a0a52b 336
ec3d41c4 337#endif /* _LINUX_VIRTIO_CONFIG_H */