Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1#ifndef _LINUX_VIRTIO_CONFIG_H
2#define _LINUX_VIRTIO_CONFIG_H
3
4#include <linux/err.h>
5#include <linux/bug.h>
6#include <linux/virtio.h>
7#include <uapi/linux/virtio_config.h>
8
9/**
10 * virtio_config_ops - operations for configuring a virtio device
11 * @get: read the value of a configuration field
12 * vdev: the virtio_device
13 * offset: the offset of the configuration field
14 * buf: the buffer to write the field value into.
15 * len: the length of the buffer
16 * @set: write the value of a configuration field
17 * vdev: the virtio_device
18 * offset: the offset of the configuration field
19 * buf: the buffer to read the field value from.
20 * len: the length of the buffer
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
27 * @reset: reset the device
28 * vdev: the virtio device
29 * After this, status and feature negotiation must be done again
30 * Device must not be reset from its vq/config callbacks, or in
31 * parallel with being added/removed.
32 * @find_vqs: find virtqueues and instantiate them.
33 * vdev: the virtio_device
34 * nvqs: the number of virtqueues to find
35 * vqs: on success, includes new virtqueues
36 * callbacks: array of callbacks, for each virtqueue
37 * include a NULL entry for vqs that do not need a callback
38 * names: array of virtqueue names (mainly for debugging)
39 * include a NULL entry for vqs unused by driver
40 * Returns 0 on success or error status
41 * @del_vqs: free virtqueues found by find_vqs().
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).
45 * @finalize_features: confirm what device features we'll be using.
46 * vdev: the virtio_device
47 * This gives the final feature bits for the device: it can change
48 * the dev->feature bits if it wants.
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.
53 * @set_vq_affinity: set the affinity for a virtqueue.
54 */
55typedef void vq_callback_t(struct virtqueue *);
56struct virtio_config_ops {
57 void (*get)(struct virtio_device *vdev, unsigned offset,
58 void *buf, unsigned len);
59 void (*set)(struct virtio_device *vdev, unsigned offset,
60 const void *buf, unsigned len);
61 u8 (*get_status)(struct virtio_device *vdev);
62 void (*set_status)(struct virtio_device *vdev, u8 status);
63 void (*reset)(struct virtio_device *vdev);
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 *);
69 u32 (*get_features)(struct virtio_device *vdev);
70 void (*finalize_features)(struct virtio_device *vdev);
71 const char *(*bus_name)(struct virtio_device *vdev);
72 int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
73};
74
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/**
80 * virtio_has_feature - helper to determine if this device has this feature.
81 * @vdev: the device
82 * @fbit: the feature bit
83 */
84static inline bool virtio_has_feature(const struct virtio_device *vdev,
85 unsigned int fbit)
86{
87 /* Did you forget to fix assumptions on max features? */
88 if (__builtin_constant_p(fbit))
89 BUILD_BUG_ON(fbit >= 32);
90 else
91 BUG_ON(fbit >= 32);
92
93 if (fbit < VIRTIO_TRANSPORT_F_START)
94 virtio_check_driver_offered_feature(vdev, fbit);
95
96 return test_bit(fbit, vdev->features);
97}
98
99static inline
100struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
101 vq_callback_t *c, const char *n)
102{
103 vq_callback_t *callbacks[] = { c };
104 const char *names[] = { n };
105 struct virtqueue *vq;
106 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
107 if (err < 0)
108 return ERR_PTR(err);
109 return vq;
110}
111
112/**
113 * virtio_device_ready - enable vq use in probe function
114 * @vdev: the device
115 *
116 * Driver must call this to use vqs in the probe function.
117 *
118 * Note: vqs are enabled automatically after probe returns.
119 */
120static inline
121void virtio_device_ready(struct virtio_device *dev)
122{
123 unsigned status = dev->config->get_status(dev);
124
125 BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
126 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
127}
128
129static inline
130const char *virtio_bus_name(struct virtio_device *vdev)
131{
132 if (!vdev->config->bus_name)
133 return "virtio";
134 return vdev->config->bus_name(vdev);
135}
136
137/**
138 * virtqueue_set_affinity - setting affinity for a virtqueue
139 * @vq: the virtqueue
140 * @cpu: the cpu no.
141 *
142 * Pay attention the function are best-effort: the affinity hint may not be set
143 * due to config support, irq type and sharing.
144 *
145 */
146static inline
147int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
148{
149 struct virtio_device *vdev = vq->vdev;
150 if (vdev->config->set_vq_affinity)
151 return vdev->config->set_vq_affinity(vq, cpu);
152 return 0;
153}
154
155/* Config space accessors. */
156#define virtio_cread(vdev, structname, member, ptr) \
157 do { \
158 /* Must match the member's type, and be integer */ \
159 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
160 (*ptr) = 1; \
161 \
162 switch (sizeof(*ptr)) { \
163 case 1: \
164 *(ptr) = virtio_cread8(vdev, \
165 offsetof(structname, member)); \
166 break; \
167 case 2: \
168 *(ptr) = virtio_cread16(vdev, \
169 offsetof(structname, member)); \
170 break; \
171 case 4: \
172 *(ptr) = virtio_cread32(vdev, \
173 offsetof(structname, member)); \
174 break; \
175 case 8: \
176 *(ptr) = virtio_cread64(vdev, \
177 offsetof(structname, member)); \
178 break; \
179 default: \
180 BUG(); \
181 } \
182 } while(0)
183
184/* Config space accessors. */
185#define virtio_cwrite(vdev, structname, member, ptr) \
186 do { \
187 /* Must match the member's type, and be integer */ \
188 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
189 BUG_ON((*ptr) == 1); \
190 \
191 switch (sizeof(*ptr)) { \
192 case 1: \
193 virtio_cwrite8(vdev, \
194 offsetof(structname, member), \
195 *(ptr)); \
196 break; \
197 case 2: \
198 virtio_cwrite16(vdev, \
199 offsetof(structname, member), \
200 *(ptr)); \
201 break; \
202 case 4: \
203 virtio_cwrite32(vdev, \
204 offsetof(structname, member), \
205 *(ptr)); \
206 break; \
207 case 8: \
208 virtio_cwrite64(vdev, \
209 offsetof(structname, member), \
210 *(ptr)); \
211 break; \
212 default: \
213 BUG(); \
214 } \
215 } while(0)
216
217static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
218{
219 u8 ret;
220 vdev->config->get(vdev, offset, &ret, sizeof(ret));
221 return ret;
222}
223
224static inline void virtio_cread_bytes(struct virtio_device *vdev,
225 unsigned int offset,
226 void *buf, size_t len)
227{
228 vdev->config->get(vdev, offset, buf, len);
229}
230
231static inline void virtio_cwrite8(struct virtio_device *vdev,
232 unsigned int offset, u8 val)
233{
234 vdev->config->set(vdev, offset, &val, sizeof(val));
235}
236
237static inline u16 virtio_cread16(struct virtio_device *vdev,
238 unsigned int offset)
239{
240 u16 ret;
241 vdev->config->get(vdev, offset, &ret, sizeof(ret));
242 return ret;
243}
244
245static inline void virtio_cwrite16(struct virtio_device *vdev,
246 unsigned int offset, u16 val)
247{
248 vdev->config->set(vdev, offset, &val, sizeof(val));
249}
250
251static inline u32 virtio_cread32(struct virtio_device *vdev,
252 unsigned int offset)
253{
254 u32 ret;
255 vdev->config->get(vdev, offset, &ret, sizeof(ret));
256 return ret;
257}
258
259static inline void virtio_cwrite32(struct virtio_device *vdev,
260 unsigned int offset, u32 val)
261{
262 vdev->config->set(vdev, offset, &val, sizeof(val));
263}
264
265static inline u64 virtio_cread64(struct virtio_device *vdev,
266 unsigned int offset)
267{
268 u64 ret;
269 vdev->config->get(vdev, offset, &ret, sizeof(ret));
270 return ret;
271}
272
273static inline void virtio_cwrite64(struct virtio_device *vdev,
274 unsigned int offset, u64 val)
275{
276 vdev->config->set(vdev, offset, &val, sizeof(val));
277}
278
279/* Conditional config space accessors. */
280#define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
281 ({ \
282 int _r = 0; \
283 if (!virtio_has_feature(vdev, fbit)) \
284 _r = -ENOENT; \
285 else \
286 virtio_cread((vdev), structname, member, ptr); \
287 _r; \
288 })
289
290#endif /* _LINUX_VIRTIO_CONFIG_H */