1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_VIRTIO_CONFIG_H
3 #define _LINUX_VIRTIO_CONFIG_H
7 #include <linux/virtio.h>
8 #include <linux/virtio_byteorder.h>
9 #include <uapi/linux/virtio_config.h>
14 * virtio_config_ops - operations for configuring a virtio device
15 * @get: read the value of a configuration field
16 * vdev: the virtio_device
17 * offset: the offset of the configuration field
18 * buf: the buffer to write the field value into.
19 * len: the length of the buffer
20 * @set: write the value of a configuration field
21 * vdev: the virtio_device
22 * offset: the offset of the configuration field
23 * buf: the buffer to read the field value from.
24 * len: the length of the buffer
25 * @generation: config generation counter
26 * vdev: the virtio_device
27 * Returns the config generation counter
28 * @get_status: read the status byte
29 * vdev: the virtio_device
30 * Returns the status byte
31 * @set_status: write the status byte
32 * vdev: the virtio_device
33 * status: the new status byte
34 * @reset: reset the device
35 * vdev: the virtio device
36 * After this, status and feature negotiation must be done again
37 * Device must not be reset from its vq/config callbacks, or in
38 * parallel with being added/removed.
39 * @find_vqs: find virtqueues and instantiate them.
40 * vdev: the virtio_device
41 * nvqs: the number of virtqueues to find
42 * vqs: on success, includes new virtqueues
43 * callbacks: array of callbacks, for each virtqueue
44 * include a NULL entry for vqs that do not need a callback
45 * names: array of virtqueue names (mainly for debugging)
46 * include a NULL entry for vqs unused by driver
47 * Returns 0 on success or error status
48 * @del_vqs: free virtqueues found by find_vqs().
49 * @get_features: get the array of feature bits for this device.
50 * vdev: the virtio_device
51 * Returns the first 32 feature bits (all we currently need).
52 * @finalize_features: confirm what device features we'll be using.
53 * vdev: the virtio_device
54 * This gives the final feature bits for the device: it can change
55 * the dev->feature bits if it wants.
56 * Returns 0 on success or error status
57 * @bus_name: return the bus name associated with the device
58 * vdev: the virtio_device
59 * This returns a pointer to the bus name a la pci_name from which
60 * the caller can then copy.
61 * @set_vq_affinity: set the affinity for a virtqueue.
62 * @get_vq_affinity: get the affinity for a virtqueue (optional).
64 typedef void vq_callback_t(struct virtqueue *);
65 struct virtio_config_ops {
66 void (*get)(struct virtio_device *vdev, unsigned offset,
67 void *buf, unsigned len);
68 void (*set)(struct virtio_device *vdev, unsigned offset,
69 const void *buf, unsigned len);
70 u32 (*generation)(struct virtio_device *vdev);
71 u8 (*get_status)(struct virtio_device *vdev);
72 void (*set_status)(struct virtio_device *vdev, u8 status);
73 void (*reset)(struct virtio_device *vdev);
74 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
75 struct virtqueue *vqs[], vq_callback_t *callbacks[],
76 const char * const names[], const bool *ctx,
77 struct irq_affinity *desc);
78 void (*del_vqs)(struct virtio_device *);
79 u64 (*get_features)(struct virtio_device *vdev);
80 int (*finalize_features)(struct virtio_device *vdev);
81 const char *(*bus_name)(struct virtio_device *vdev);
82 int (*set_vq_affinity)(struct virtqueue *vq,
83 const struct cpumask *cpu_mask);
84 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
88 /* If driver didn't advertise the feature, it will never appear. */
89 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
93 * __virtio_test_bit - helper to test feature bits. For use by transports.
94 * Devices should normally use virtio_has_feature,
95 * which includes more checks.
97 * @fbit: the feature bit
99 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
102 /* Did you forget to fix assumptions on max features? */
103 if (__builtin_constant_p(fbit))
104 BUILD_BUG_ON(fbit >= 64);
108 return vdev->features & BIT_ULL(fbit);
112 * __virtio_set_bit - helper to set feature bits. For use by transports.
114 * @fbit: the feature bit
116 static inline void __virtio_set_bit(struct virtio_device *vdev,
119 /* Did you forget to fix assumptions on max features? */
120 if (__builtin_constant_p(fbit))
121 BUILD_BUG_ON(fbit >= 64);
125 vdev->features |= BIT_ULL(fbit);
129 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
131 * @fbit: the feature bit
133 static inline void __virtio_clear_bit(struct virtio_device *vdev,
136 /* Did you forget to fix assumptions on max features? */
137 if (__builtin_constant_p(fbit))
138 BUILD_BUG_ON(fbit >= 64);
142 vdev->features &= ~BIT_ULL(fbit);
146 * virtio_has_feature - helper to determine if this device has this feature.
148 * @fbit: the feature bit
150 static inline bool virtio_has_feature(const struct virtio_device *vdev,
153 if (fbit < VIRTIO_TRANSPORT_F_START)
154 virtio_check_driver_offered_feature(vdev, fbit);
156 return __virtio_test_bit(vdev, fbit);
160 * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
163 static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
166 * Note the reverse polarity of the quirk feature (compared to most
167 * other features), this is for compatibility with legacy systems.
169 return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
173 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
174 vq_callback_t *c, const char *n)
176 vq_callback_t *callbacks[] = { c };
177 const char *names[] = { n };
178 struct virtqueue *vq;
179 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL,
187 int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
188 struct virtqueue *vqs[], vq_callback_t *callbacks[],
189 const char * const names[],
190 struct irq_affinity *desc)
192 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc);
196 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
197 struct virtqueue *vqs[], vq_callback_t *callbacks[],
198 const char * const names[], const bool *ctx,
199 struct irq_affinity *desc)
201 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx,
206 * virtio_device_ready - enable vq use in probe function
209 * Driver must call this to use vqs in the probe function.
211 * Note: vqs are enabled automatically after probe returns.
214 void virtio_device_ready(struct virtio_device *dev)
216 unsigned status = dev->config->get_status(dev);
218 BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
219 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
223 const char *virtio_bus_name(struct virtio_device *vdev)
225 if (!vdev->config->bus_name)
227 return vdev->config->bus_name(vdev);
231 * virtqueue_set_affinity - setting affinity for a virtqueue
235 * Pay attention the function are best-effort: the affinity hint may not be set
236 * due to config support, irq type and sharing.
240 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
242 struct virtio_device *vdev = vq->vdev;
243 if (vdev->config->set_vq_affinity)
244 return vdev->config->set_vq_affinity(vq, cpu_mask);
248 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
250 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
251 virtio_legacy_is_little_endian();
254 /* Memory accessors */
255 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
257 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
260 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
262 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
265 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
267 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
270 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
272 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
275 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
277 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
280 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
282 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
285 /* Config space accessors. */
286 #define virtio_cread(vdev, structname, member, ptr) \
288 /* Must match the member's type, and be integer */ \
289 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
292 switch (sizeof(*ptr)) { \
294 *(ptr) = virtio_cread8(vdev, \
295 offsetof(structname, member)); \
298 *(ptr) = virtio_cread16(vdev, \
299 offsetof(structname, member)); \
302 *(ptr) = virtio_cread32(vdev, \
303 offsetof(structname, member)); \
306 *(ptr) = virtio_cread64(vdev, \
307 offsetof(structname, member)); \
314 /* Config space accessors. */
315 #define virtio_cwrite(vdev, structname, member, ptr) \
317 /* Must match the member's type, and be integer */ \
318 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
319 BUG_ON((*ptr) == 1); \
321 switch (sizeof(*ptr)) { \
323 virtio_cwrite8(vdev, \
324 offsetof(structname, member), \
328 virtio_cwrite16(vdev, \
329 offsetof(structname, member), \
333 virtio_cwrite32(vdev, \
334 offsetof(structname, member), \
338 virtio_cwrite64(vdev, \
339 offsetof(structname, member), \
347 /* Read @count fields, @bytes each. */
348 static inline void __virtio_cread_many(struct virtio_device *vdev,
350 void *buf, size_t count, size_t bytes)
352 u32 old, gen = vdev->config->generation ?
353 vdev->config->generation(vdev) : 0;
359 for (i = 0; i < count; i++)
360 vdev->config->get(vdev, offset + bytes * i,
361 buf + i * bytes, bytes);
363 gen = vdev->config->generation ?
364 vdev->config->generation(vdev) : 0;
365 } while (gen != old);
368 static inline void virtio_cread_bytes(struct virtio_device *vdev,
370 void *buf, size_t len)
372 __virtio_cread_many(vdev, offset, buf, len, 1);
375 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
378 vdev->config->get(vdev, offset, &ret, sizeof(ret));
382 static inline void virtio_cwrite8(struct virtio_device *vdev,
383 unsigned int offset, u8 val)
385 vdev->config->set(vdev, offset, &val, sizeof(val));
388 static inline u16 virtio_cread16(struct virtio_device *vdev,
392 vdev->config->get(vdev, offset, &ret, sizeof(ret));
393 return virtio16_to_cpu(vdev, (__force __virtio16)ret);
396 static inline void virtio_cwrite16(struct virtio_device *vdev,
397 unsigned int offset, u16 val)
399 val = (__force u16)cpu_to_virtio16(vdev, val);
400 vdev->config->set(vdev, offset, &val, sizeof(val));
403 static inline u32 virtio_cread32(struct virtio_device *vdev,
407 vdev->config->get(vdev, offset, &ret, sizeof(ret));
408 return virtio32_to_cpu(vdev, (__force __virtio32)ret);
411 static inline void virtio_cwrite32(struct virtio_device *vdev,
412 unsigned int offset, u32 val)
414 val = (__force u32)cpu_to_virtio32(vdev, val);
415 vdev->config->set(vdev, offset, &val, sizeof(val));
418 static inline u64 virtio_cread64(struct virtio_device *vdev,
422 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
423 return virtio64_to_cpu(vdev, (__force __virtio64)ret);
426 static inline void virtio_cwrite64(struct virtio_device *vdev,
427 unsigned int offset, u64 val)
429 val = (__force u64)cpu_to_virtio64(vdev, val);
430 vdev->config->set(vdev, offset, &val, sizeof(val));
433 /* Conditional config space accessors. */
434 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
437 if (!virtio_has_feature(vdev, fbit)) \
440 virtio_cread((vdev), structname, member, ptr); \
444 #endif /* _LINUX_VIRTIO_CONFIG_H */