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 * Note: Do not assume that a transport implements all of the operations
16 * getting/setting a value as a simple read/write! Generally speaking,
17 * any of @get/@set, @get_status/@set_status, or @get_features/
18 * @finalize_features are NOT safe to be called from an atomic
20 * @get: read the value of a configuration field
21 * vdev: the virtio_device
22 * offset: the offset of the configuration field
23 * buf: the buffer to write the field value into.
24 * len: the length of the buffer
25 * @set: write the value of a configuration field
26 * vdev: the virtio_device
27 * offset: the offset of the configuration field
28 * buf: the buffer to read the field value from.
29 * len: the length of the buffer
30 * @generation: config generation counter (optional)
31 * vdev: the virtio_device
32 * Returns the config generation counter
33 * @get_status: read the status byte
34 * vdev: the virtio_device
35 * Returns the status byte
36 * @set_status: write the status byte
37 * vdev: the virtio_device
38 * status: the new status byte
39 * @reset: reset the device
40 * vdev: the virtio device
41 * After this, status and feature negotiation must be done again
42 * Device must not be reset from its vq/config callbacks, or in
43 * parallel with being added/removed.
44 * @find_vqs: find virtqueues and instantiate them.
45 * vdev: the virtio_device
46 * nvqs: the number of virtqueues to find
47 * vqs: on success, includes new virtqueues
48 * callbacks: array of callbacks, for each virtqueue
49 * include a NULL entry for vqs that do not need a callback
50 * names: array of virtqueue names (mainly for debugging)
51 * include a NULL entry for vqs unused by driver
52 * Returns 0 on success or error status
53 * @del_vqs: free virtqueues found by find_vqs().
54 * @get_features: get the array of feature bits for this device.
55 * vdev: the virtio_device
56 * Returns the first 64 feature bits (all we currently need).
57 * @finalize_features: confirm what device features we'll be using.
58 * vdev: the virtio_device
59 * This gives the final feature bits for the device: it can change
60 * the dev->feature bits if it wants.
61 * Returns 0 on success or error status
62 * @bus_name: return the bus name associated with the device (optional)
63 * vdev: the virtio_device
64 * This returns a pointer to the bus name a la pci_name from which
65 * the caller can then copy.
66 * @set_vq_affinity: set the affinity for a virtqueue (optional).
67 * @get_vq_affinity: get the affinity for a virtqueue (optional).
69 typedef void vq_callback_t(struct virtqueue *);
70 struct virtio_config_ops {
71 void (*get)(struct virtio_device *vdev, unsigned offset,
72 void *buf, unsigned len);
73 void (*set)(struct virtio_device *vdev, unsigned offset,
74 const void *buf, unsigned len);
75 u32 (*generation)(struct virtio_device *vdev);
76 u8 (*get_status)(struct virtio_device *vdev);
77 void (*set_status)(struct virtio_device *vdev, u8 status);
78 void (*reset)(struct virtio_device *vdev);
79 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
80 struct virtqueue *vqs[], vq_callback_t *callbacks[],
81 const char * const names[], const bool *ctx,
82 struct irq_affinity *desc);
83 void (*del_vqs)(struct virtio_device *);
84 u64 (*get_features)(struct virtio_device *vdev);
85 int (*finalize_features)(struct virtio_device *vdev);
86 const char *(*bus_name)(struct virtio_device *vdev);
87 int (*set_vq_affinity)(struct virtqueue *vq,
88 const struct cpumask *cpu_mask);
89 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
93 /* If driver didn't advertise the feature, it will never appear. */
94 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
98 * __virtio_test_bit - helper to test feature bits. For use by transports.
99 * Devices should normally use virtio_has_feature,
100 * which includes more checks.
102 * @fbit: the feature bit
104 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
107 /* Did you forget to fix assumptions on max features? */
108 if (__builtin_constant_p(fbit))
109 BUILD_BUG_ON(fbit >= 64);
113 return vdev->features & BIT_ULL(fbit);
117 * __virtio_set_bit - helper to set feature bits. For use by transports.
119 * @fbit: the feature bit
121 static inline void __virtio_set_bit(struct virtio_device *vdev,
124 /* Did you forget to fix assumptions on max features? */
125 if (__builtin_constant_p(fbit))
126 BUILD_BUG_ON(fbit >= 64);
130 vdev->features |= BIT_ULL(fbit);
134 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
136 * @fbit: the feature bit
138 static inline void __virtio_clear_bit(struct virtio_device *vdev,
141 /* Did you forget to fix assumptions on max features? */
142 if (__builtin_constant_p(fbit))
143 BUILD_BUG_ON(fbit >= 64);
147 vdev->features &= ~BIT_ULL(fbit);
151 * virtio_has_feature - helper to determine if this device has this feature.
153 * @fbit: the feature bit
155 static inline bool virtio_has_feature(const struct virtio_device *vdev,
158 if (fbit < VIRTIO_TRANSPORT_F_START)
159 virtio_check_driver_offered_feature(vdev, fbit);
161 return __virtio_test_bit(vdev, fbit);
165 * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
168 static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
171 * Note the reverse polarity of the quirk feature (compared to most
172 * other features), this is for compatibility with legacy systems.
174 return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
178 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
179 vq_callback_t *c, const char *n)
181 vq_callback_t *callbacks[] = { c };
182 const char *names[] = { n };
183 struct virtqueue *vq;
184 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL,
192 int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
193 struct virtqueue *vqs[], vq_callback_t *callbacks[],
194 const char * const names[],
195 struct irq_affinity *desc)
197 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc);
201 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
202 struct virtqueue *vqs[], vq_callback_t *callbacks[],
203 const char * const names[], const bool *ctx,
204 struct irq_affinity *desc)
206 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx,
211 * virtio_device_ready - enable vq use in probe function
214 * Driver must call this to use vqs in the probe function.
216 * Note: vqs are enabled automatically after probe returns.
219 void virtio_device_ready(struct virtio_device *dev)
221 unsigned status = dev->config->get_status(dev);
223 BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
224 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
228 const char *virtio_bus_name(struct virtio_device *vdev)
230 if (!vdev->config->bus_name)
232 return vdev->config->bus_name(vdev);
236 * virtqueue_set_affinity - setting affinity for a virtqueue
240 * Pay attention the function are best-effort: the affinity hint may not be set
241 * due to config support, irq type and sharing.
245 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
247 struct virtio_device *vdev = vq->vdev;
248 if (vdev->config->set_vq_affinity)
249 return vdev->config->set_vq_affinity(vq, cpu_mask);
253 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
255 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
256 virtio_legacy_is_little_endian();
259 /* Memory accessors */
260 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
262 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
265 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
267 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
270 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
272 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
275 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
277 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
280 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
282 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
285 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
287 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
290 /* Config space accessors. */
291 #define virtio_cread(vdev, structname, member, ptr) \
294 /* Must match the member's type, and be integer */ \
295 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
298 switch (sizeof(*ptr)) { \
300 *(ptr) = virtio_cread8(vdev, \
301 offsetof(structname, member)); \
304 *(ptr) = virtio_cread16(vdev, \
305 offsetof(structname, member)); \
308 *(ptr) = virtio_cread32(vdev, \
309 offsetof(structname, member)); \
312 *(ptr) = virtio_cread64(vdev, \
313 offsetof(structname, member)); \
320 /* Config space accessors. */
321 #define virtio_cwrite(vdev, structname, member, ptr) \
324 /* Must match the member's type, and be integer */ \
325 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
326 BUG_ON((*ptr) == 1); \
328 switch (sizeof(*ptr)) { \
330 virtio_cwrite8(vdev, \
331 offsetof(structname, member), \
335 virtio_cwrite16(vdev, \
336 offsetof(structname, member), \
340 virtio_cwrite32(vdev, \
341 offsetof(structname, member), \
345 virtio_cwrite64(vdev, \
346 offsetof(structname, member), \
354 /* Read @count fields, @bytes each. */
355 static inline void __virtio_cread_many(struct virtio_device *vdev,
357 void *buf, size_t count, size_t bytes)
359 u32 old, gen = vdev->config->generation ?
360 vdev->config->generation(vdev) : 0;
367 for (i = 0; i < count; i++)
368 vdev->config->get(vdev, offset + bytes * i,
369 buf + i * bytes, bytes);
371 gen = vdev->config->generation ?
372 vdev->config->generation(vdev) : 0;
373 } while (gen != old);
376 static inline void virtio_cread_bytes(struct virtio_device *vdev,
378 void *buf, size_t len)
380 __virtio_cread_many(vdev, offset, buf, len, 1);
383 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
388 vdev->config->get(vdev, offset, &ret, sizeof(ret));
392 static inline void virtio_cwrite8(struct virtio_device *vdev,
393 unsigned int offset, u8 val)
396 vdev->config->set(vdev, offset, &val, sizeof(val));
399 static inline u16 virtio_cread16(struct virtio_device *vdev,
405 vdev->config->get(vdev, offset, &ret, sizeof(ret));
406 return virtio16_to_cpu(vdev, (__force __virtio16)ret);
409 static inline void virtio_cwrite16(struct virtio_device *vdev,
410 unsigned int offset, u16 val)
413 val = (__force u16)cpu_to_virtio16(vdev, val);
414 vdev->config->set(vdev, offset, &val, sizeof(val));
417 static inline u32 virtio_cread32(struct virtio_device *vdev,
423 vdev->config->get(vdev, offset, &ret, sizeof(ret));
424 return virtio32_to_cpu(vdev, (__force __virtio32)ret);
427 static inline void virtio_cwrite32(struct virtio_device *vdev,
428 unsigned int offset, u32 val)
431 val = (__force u32)cpu_to_virtio32(vdev, val);
432 vdev->config->set(vdev, offset, &val, sizeof(val));
435 static inline u64 virtio_cread64(struct virtio_device *vdev,
439 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
440 return virtio64_to_cpu(vdev, (__force __virtio64)ret);
443 static inline void virtio_cwrite64(struct virtio_device *vdev,
444 unsigned int offset, u64 val)
447 val = (__force u64)cpu_to_virtio64(vdev, val);
448 vdev->config->set(vdev, offset, &val, sizeof(val));
451 /* Conditional config space accessors. */
452 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
455 if (!virtio_has_feature(vdev, fbit)) \
458 virtio_cread((vdev), structname, member, ptr); \
462 #endif /* _LINUX_VIRTIO_CONFIG_H */