Merge tag 'v3.13-rc1' into patchwork
[firefly-linux-kernel-4.4.55.git] / include / linux / virtio_config.h
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  */
55 typedef void vq_callback_t(struct virtqueue *);
56 struct 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. */
76 void 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  */
84 static 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
99 static inline
100 struct 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 static inline
113 const char *virtio_bus_name(struct virtio_device *vdev)
114 {
115         if (!vdev->config->bus_name)
116                 return "virtio";
117         return vdev->config->bus_name(vdev);
118 }
119
120 /**
121  * virtqueue_set_affinity - setting affinity for a virtqueue
122  * @vq: the virtqueue
123  * @cpu: the cpu no.
124  *
125  * Pay attention the function are best-effort: the affinity hint may not be set
126  * due to config support, irq type and sharing.
127  *
128  */
129 static inline
130 int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
131 {
132         struct virtio_device *vdev = vq->vdev;
133         if (vdev->config->set_vq_affinity)
134                 return vdev->config->set_vq_affinity(vq, cpu);
135         return 0;
136 }
137
138 /* Config space accessors. */
139 #define virtio_cread(vdev, structname, member, ptr)                     \
140         do {                                                            \
141                 /* Must match the member's type, and be integer */      \
142                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
143                         (*ptr) = 1;                                     \
144                                                                         \
145                 switch (sizeof(*ptr)) {                                 \
146                 case 1:                                                 \
147                         *(ptr) = virtio_cread8(vdev,                    \
148                                                offsetof(structname, member)); \
149                         break;                                          \
150                 case 2:                                                 \
151                         *(ptr) = virtio_cread16(vdev,                   \
152                                                 offsetof(structname, member)); \
153                         break;                                          \
154                 case 4:                                                 \
155                         *(ptr) = virtio_cread32(vdev,                   \
156                                                 offsetof(structname, member)); \
157                         break;                                          \
158                 case 8:                                                 \
159                         *(ptr) = virtio_cread64(vdev,                   \
160                                                 offsetof(structname, member)); \
161                         break;                                          \
162                 default:                                                \
163                         BUG();                                          \
164                 }                                                       \
165         } while(0)
166
167 /* Config space accessors. */
168 #define virtio_cwrite(vdev, structname, member, ptr)                    \
169         do {                                                            \
170                 /* Must match the member's type, and be integer */      \
171                 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
172                         BUG_ON((*ptr) == 1);                            \
173                                                                         \
174                 switch (sizeof(*ptr)) {                                 \
175                 case 1:                                                 \
176                         virtio_cwrite8(vdev,                            \
177                                        offsetof(structname, member),    \
178                                        *(ptr));                         \
179                         break;                                          \
180                 case 2:                                                 \
181                         virtio_cwrite16(vdev,                           \
182                                         offsetof(structname, member),   \
183                                         *(ptr));                        \
184                         break;                                          \
185                 case 4:                                                 \
186                         virtio_cwrite32(vdev,                           \
187                                         offsetof(structname, member),   \
188                                         *(ptr));                        \
189                         break;                                          \
190                 case 8:                                                 \
191                         virtio_cwrite64(vdev,                           \
192                                         offsetof(structname, member),   \
193                                         *(ptr));                        \
194                         break;                                          \
195                 default:                                                \
196                         BUG();                                          \
197                 }                                                       \
198         } while(0)
199
200 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
201 {
202         u8 ret;
203         vdev->config->get(vdev, offset, &ret, sizeof(ret));
204         return ret;
205 }
206
207 static inline void virtio_cread_bytes(struct virtio_device *vdev,
208                                       unsigned int offset,
209                                       void *buf, size_t len)
210 {
211         vdev->config->get(vdev, offset, buf, len);
212 }
213
214 static inline void virtio_cwrite8(struct virtio_device *vdev,
215                                   unsigned int offset, u8 val)
216 {
217         vdev->config->set(vdev, offset, &val, sizeof(val));
218 }
219
220 static inline u16 virtio_cread16(struct virtio_device *vdev,
221                                  unsigned int offset)
222 {
223         u16 ret;
224         vdev->config->get(vdev, offset, &ret, sizeof(ret));
225         return ret;
226 }
227
228 static inline void virtio_cwrite16(struct virtio_device *vdev,
229                                    unsigned int offset, u16 val)
230 {
231         vdev->config->set(vdev, offset, &val, sizeof(val));
232 }
233
234 static inline u32 virtio_cread32(struct virtio_device *vdev,
235                                  unsigned int offset)
236 {
237         u32 ret;
238         vdev->config->get(vdev, offset, &ret, sizeof(ret));
239         return ret;
240 }
241
242 static inline void virtio_cwrite32(struct virtio_device *vdev,
243                                    unsigned int offset, u32 val)
244 {
245         vdev->config->set(vdev, offset, &val, sizeof(val));
246 }
247
248 static inline u64 virtio_cread64(struct virtio_device *vdev,
249                                  unsigned int offset)
250 {
251         u64 ret;
252         vdev->config->get(vdev, offset, &ret, sizeof(ret));
253         return ret;
254 }
255
256 static inline void virtio_cwrite64(struct virtio_device *vdev,
257                                    unsigned int offset, u64 val)
258 {
259         vdev->config->set(vdev, offset, &val, sizeof(val));
260 }
261
262 /* Conditional config space accessors. */
263 #define virtio_cread_feature(vdev, fbit, structname, member, ptr)       \
264         ({                                                              \
265                 int _r = 0;                                             \
266                 if (!virtio_has_feature(vdev, fbit))                    \
267                         _r = -ENOENT;                                   \
268                 else                                                    \
269                         virtio_cread((vdev), structname, member, ptr);  \
270                 _r;                                                     \
271         })
272
273 #endif /* _LINUX_VIRTIO_CONFIG_H */