1 #ifndef _LINUX_VIRTIO_CONFIG_H
2 #define _LINUX_VIRTIO_CONFIG_H
6 #include <linux/virtio.h>
7 #include <linux/virtio_byteorder.h>
8 #include <uapi/linux/virtio_config.h>
11 * virtio_config_ops - operations for configuring a virtio device
12 * @get: read the value of a configuration field
13 * vdev: the virtio_device
14 * offset: the offset of the configuration field
15 * buf: the buffer to write the field value into.
16 * len: the length of the buffer
17 * @set: write the value of a configuration field
18 * vdev: the virtio_device
19 * offset: the offset of the configuration field
20 * buf: the buffer to read the field value from.
21 * len: the length of the buffer
22 * @generation: config generation counter
23 * vdev: the virtio_device
24 * Returns the config generation counter
25 * @get_status: read the status byte
26 * vdev: the virtio_device
27 * Returns the status byte
28 * @set_status: write the status byte
29 * vdev: the virtio_device
30 * status: the new status byte
31 * @reset: reset the device
32 * vdev: the virtio device
33 * After this, status and feature negotiation must be done again
34 * Device must not be reset from its vq/config callbacks, or in
35 * parallel with being added/removed.
36 * @find_vqs: find virtqueues and instantiate them.
37 * vdev: the virtio_device
38 * nvqs: the number of virtqueues to find
39 * vqs: on success, includes new virtqueues
40 * callbacks: array of callbacks, for each virtqueue
41 * include a NULL entry for vqs that do not need a callback
42 * names: array of virtqueue names (mainly for debugging)
43 * include a NULL entry for vqs unused by driver
44 * Returns 0 on success or error status
45 * @del_vqs: free virtqueues found by find_vqs().
46 * @get_features: get the array of feature bits for this device.
47 * vdev: the virtio_device
48 * Returns the first 32 feature bits (all we currently need).
49 * @finalize_features: confirm what device features we'll be using.
50 * vdev: the virtio_device
51 * This gives the final feature bits for the device: it can change
52 * the dev->feature bits if it wants.
53 * Returns 0 on success or error status
54 * @bus_name: return the bus name associated with the device
55 * vdev: the virtio_device
56 * This returns a pointer to the bus name a la pci_name from which
57 * the caller can then copy.
58 * @set_vq_affinity: set the affinity for a virtqueue.
60 typedef void vq_callback_t(struct virtqueue *);
61 struct virtio_config_ops {
62 void (*get)(struct virtio_device *vdev, unsigned offset,
63 void *buf, unsigned len);
64 void (*set)(struct virtio_device *vdev, unsigned offset,
65 const void *buf, unsigned len);
66 u32 (*generation)(struct virtio_device *vdev);
67 u8 (*get_status)(struct virtio_device *vdev);
68 void (*set_status)(struct virtio_device *vdev, u8 status);
69 void (*reset)(struct virtio_device *vdev);
70 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
71 struct virtqueue *vqs[],
72 vq_callback_t *callbacks[],
73 const char * const names[]);
74 void (*del_vqs)(struct virtio_device *);
75 u64 (*get_features)(struct virtio_device *vdev);
76 int (*finalize_features)(struct virtio_device *vdev);
77 const char *(*bus_name)(struct virtio_device *vdev);
78 int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
81 /* If driver didn't advertise the feature, it will never appear. */
82 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
86 * __virtio_test_bit - helper to test feature bits. For use by transports.
87 * Devices should normally use virtio_has_feature,
88 * which includes more checks.
90 * @fbit: the feature bit
92 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
95 /* Did you forget to fix assumptions on max features? */
96 if (__builtin_constant_p(fbit))
97 BUILD_BUG_ON(fbit >= 64);
101 return vdev->features & BIT_ULL(fbit);
105 * __virtio_set_bit - helper to set feature bits. For use by transports.
107 * @fbit: the feature bit
109 static inline void __virtio_set_bit(struct virtio_device *vdev,
112 /* Did you forget to fix assumptions on max features? */
113 if (__builtin_constant_p(fbit))
114 BUILD_BUG_ON(fbit >= 64);
118 vdev->features |= BIT_ULL(fbit);
122 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
124 * @fbit: the feature bit
126 static inline void __virtio_clear_bit(struct virtio_device *vdev,
129 /* Did you forget to fix assumptions on max features? */
130 if (__builtin_constant_p(fbit))
131 BUILD_BUG_ON(fbit >= 64);
135 vdev->features &= ~BIT_ULL(fbit);
139 * virtio_has_feature - helper to determine if this device has this feature.
141 * @fbit: the feature bit
143 static inline bool virtio_has_feature(const struct virtio_device *vdev,
146 if (fbit < VIRTIO_TRANSPORT_F_START)
147 virtio_check_driver_offered_feature(vdev, fbit);
149 return __virtio_test_bit(vdev, fbit);
153 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
154 vq_callback_t *c, const char *n)
156 vq_callback_t *callbacks[] = { c };
157 const char *names[] = { n };
158 struct virtqueue *vq;
159 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
166 * virtio_device_ready - enable vq use in probe function
169 * Driver must call this to use vqs in the probe function.
171 * Note: vqs are enabled automatically after probe returns.
174 void virtio_device_ready(struct virtio_device *dev)
176 unsigned status = dev->config->get_status(dev);
178 BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
179 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
183 const char *virtio_bus_name(struct virtio_device *vdev)
185 if (!vdev->config->bus_name)
187 return vdev->config->bus_name(vdev);
191 * virtqueue_set_affinity - setting affinity for a virtqueue
195 * Pay attention the function are best-effort: the affinity hint may not be set
196 * due to config support, irq type and sharing.
200 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
202 struct virtio_device *vdev = vq->vdev;
203 if (vdev->config->set_vq_affinity)
204 return vdev->config->set_vq_affinity(vq, cpu);
208 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
210 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
211 virtio_legacy_is_little_endian();
214 /* Memory accessors */
215 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
217 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
220 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
222 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
225 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
227 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
230 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
232 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
235 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
237 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
240 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
242 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
245 /* Config space accessors. */
246 #define virtio_cread(vdev, structname, member, ptr) \
248 /* Must match the member's type, and be integer */ \
249 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
252 switch (sizeof(*ptr)) { \
254 *(ptr) = virtio_cread8(vdev, \
255 offsetof(structname, member)); \
258 *(ptr) = virtio_cread16(vdev, \
259 offsetof(structname, member)); \
262 *(ptr) = virtio_cread32(vdev, \
263 offsetof(structname, member)); \
266 *(ptr) = virtio_cread64(vdev, \
267 offsetof(structname, member)); \
274 /* Config space accessors. */
275 #define virtio_cwrite(vdev, structname, member, ptr) \
277 /* Must match the member's type, and be integer */ \
278 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
279 BUG_ON((*ptr) == 1); \
281 switch (sizeof(*ptr)) { \
283 virtio_cwrite8(vdev, \
284 offsetof(structname, member), \
288 virtio_cwrite16(vdev, \
289 offsetof(structname, member), \
293 virtio_cwrite32(vdev, \
294 offsetof(structname, member), \
298 virtio_cwrite64(vdev, \
299 offsetof(structname, member), \
307 /* Read @count fields, @bytes each. */
308 static inline void __virtio_cread_many(struct virtio_device *vdev,
310 void *buf, size_t count, size_t bytes)
312 u32 old, gen = vdev->config->generation ?
313 vdev->config->generation(vdev) : 0;
319 for (i = 0; i < count; i++)
320 vdev->config->get(vdev, offset + bytes * i,
321 buf + i * bytes, bytes);
323 gen = vdev->config->generation ?
324 vdev->config->generation(vdev) : 0;
325 } while (gen != old);
328 static inline void virtio_cread_bytes(struct virtio_device *vdev,
330 void *buf, size_t len)
332 __virtio_cread_many(vdev, offset, buf, len, 1);
335 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
338 vdev->config->get(vdev, offset, &ret, sizeof(ret));
342 static inline void virtio_cwrite8(struct virtio_device *vdev,
343 unsigned int offset, u8 val)
345 vdev->config->set(vdev, offset, &val, sizeof(val));
348 static inline u16 virtio_cread16(struct virtio_device *vdev,
352 vdev->config->get(vdev, offset, &ret, sizeof(ret));
353 return virtio16_to_cpu(vdev, (__force __virtio16)ret);
356 static inline void virtio_cwrite16(struct virtio_device *vdev,
357 unsigned int offset, u16 val)
359 val = (__force u16)cpu_to_virtio16(vdev, val);
360 vdev->config->set(vdev, offset, &val, sizeof(val));
363 static inline u32 virtio_cread32(struct virtio_device *vdev,
367 vdev->config->get(vdev, offset, &ret, sizeof(ret));
368 return virtio32_to_cpu(vdev, (__force __virtio32)ret);
371 static inline void virtio_cwrite32(struct virtio_device *vdev,
372 unsigned int offset, u32 val)
374 val = (__force u32)cpu_to_virtio32(vdev, val);
375 vdev->config->set(vdev, offset, &val, sizeof(val));
378 static inline u64 virtio_cread64(struct virtio_device *vdev,
382 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
383 return virtio64_to_cpu(vdev, (__force __virtio64)ret);
386 static inline void virtio_cwrite64(struct virtio_device *vdev,
387 unsigned int offset, u64 val)
389 val = (__force u64)cpu_to_virtio64(vdev, val);
390 vdev->config->set(vdev, offset, &val, sizeof(val));
393 /* Conditional config space accessors. */
394 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
397 if (!virtio_has_feature(vdev, fbit)) \
400 virtio_cread((vdev), structname, member, ptr); \
404 #endif /* _LINUX_VIRTIO_CONFIG_H */