aboutsummaryrefslogtreecommitdiff
path: root/include/linux/virtio_config.h
blob: ca3ed78e5ec73b5968ebce4c07e0927373413b93 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
#ifndef _LINUX_VIRTIO_CONFIG_H
#define _LINUX_VIRTIO_CONFIG_H

#include <linux/err.h>
#include <linux/bug.h>
#include <linux/virtio.h>
#include <linux/virtio_byteorder.h>
#include <uapi/linux/virtio_config.h>

/**
 * virtio_config_ops - operations for configuring a virtio device
 * @get: read the value of a configuration field
 *	vdev: the virtio_device
 *	offset: the offset of the configuration field
 *	buf: the buffer to write the field value into.
 *	len: the length of the buffer
 * @set: write the value of a configuration field
 *	vdev: the virtio_device
 *	offset: the offset of the configuration field
 *	buf: the buffer to read the field value from.
 *	len: the length of the buffer
 * @generation: config generation counter
 *	vdev: the virtio_device
 *	Returns the config generation counter
 * @get_status: read the status byte
 *	vdev: the virtio_device
 *	Returns the status byte
 * @set_status: write the status byte
 *	vdev: the virtio_device
 *	status: the new status byte
 * @reset: reset the device
 *	vdev: the virtio device
 *	After this, status and feature negotiation must be done again
 *	Device must not be reset from its vq/config callbacks, or in
 *	parallel with being added/removed.
 * @find_vqs: find virtqueues and instantiate them.
 *	vdev: the virtio_device
 *	nvqs: the number of virtqueues to find
 *	vqs: on success, includes new virtqueues
 *	callbacks: array of callbacks, for each virtqueue
 *		include a NULL entry for vqs that do not need a callback
 *	names: array of virtqueue names (mainly for debugging)
 *		include a NULL entry for vqs unused by driver
 *	Returns 0 on success or error status
 * @del_vqs: free virtqueues found by find_vqs().
 * @get_features: get the array of feature bits for this device.
 *	vdev: the virtio_device
 *	Returns the first 32 feature bits (all we currently need).
 * @finalize_features: confirm what device features we'll be using.
 *	vdev: the virtio_device
 *	This gives the final feature bits for the device: it can change
 *	the dev->feature bits if it wants.
 *	Returns 0 on success or error status
 * @bus_name: return the bus name associated with the device
 *	vdev: the virtio_device
 *      This returns a pointer to the bus name a la pci_name from which
 *      the caller can then copy.
 * @set_vq_affinity: set the affinity for a virtqueue.
 */
typedef void vq_callback_t(struct virtqueue *);
struct virtio_config_ops {
	void (*get)(struct virtio_device *vdev, unsigned offset,
		    void *buf, unsigned len);
	void (*set)(struct virtio_device *vdev, unsigned offset,
		    const void *buf, unsigned len);
	u32 (*generation)(struct virtio_device *vdev);
	u8 (*get_status)(struct virtio_device *vdev);
	void (*set_status)(struct virtio_device *vdev, u8 status);
	void (*reset)(struct virtio_device *vdev);
	int (*find_vqs)(struct virtio_device *, unsigned nvqs,
			struct virtqueue *vqs[],
			vq_callback_t *callbacks[],
			const char *names[]);
	void (*del_vqs)(struct virtio_device *);
	u64 (*get_features)(struct virtio_device *vdev);
	int (*finalize_features)(struct virtio_device *vdev);
	const char *(*bus_name)(struct virtio_device *vdev);
	int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
};

/* If driver didn't advertise the feature, it will never appear. */
void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
					 unsigned int fbit);

/**
 * __virtio_test_bit - helper to test feature bits. For use by transports.
 *                     Devices should normally use virtio_has_feature,
 *                     which includes more checks.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline bool __virtio_test_bit(const struct virtio_device *vdev,
				     unsigned int fbit)
{
	/* Did you forget to fix assumptions on max features? */
	if (__builtin_constant_p(fbit))
		BUILD_BUG_ON(fbit >= 64);
	else
		BUG_ON(fbit >= 64);

	return vdev->features & BIT_ULL(fbit);
}

/**
 * __virtio_set_bit - helper to set feature bits. For use by transports.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline void __virtio_set_bit(struct virtio_device *vdev,
				    unsigned int fbit)
{
	/* Did you forget to fix assumptions on max features? */
	if (__builtin_constant_p(fbit))
		BUILD_BUG_ON(fbit >= 64);
	else
		BUG_ON(fbit >= 64);

	vdev->features |= BIT_ULL(fbit);
}

/**
 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline void __virtio_clear_bit(struct virtio_device *vdev,
				      unsigned int fbit)
{
	/* Did you forget to fix assumptions on max features? */
	if (__builtin_constant_p(fbit))
		BUILD_BUG_ON(fbit >= 64);
	else
		BUG_ON(fbit >= 64);

	vdev->features &= ~BIT_ULL(fbit);
}

/**
 * virtio_has_feature - helper to determine if this device has this feature.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline bool virtio_has_feature(const struct virtio_device *vdev,
				      unsigned int fbit)
{
	if (fbit < VIRTIO_TRANSPORT_F_START)
		virtio_check_driver_offered_feature(vdev, fbit);

	return __virtio_test_bit(vdev, fbit);
}

static inline
struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
					vq_callback_t *c, const char *n)
{
	vq_callback_t *callbacks[] = { c };
	const char *names[] = { n };
	struct virtqueue *vq;
	int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
	if (err < 0)
		return ERR_PTR(err);
	return vq;
}

/**
 * virtio_device_ready - enable vq use in probe function
 * @vdev: the device
 *
 * Driver must call this to use vqs in the probe function.
 *
 * Note: vqs are enabled automatically after probe returns.
 */
static inline
void virtio_device_ready(struct virtio_device *dev)
{
	unsigned status = dev->config->get_status(dev);

	BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
	dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
}

static inline
const char *virtio_bus_name(struct virtio_device *vdev)
{
	if (!vdev->config->bus_name)
		return "virtio";
	return vdev->config->bus_name(vdev);
}

/**
 * virtqueue_set_affinity - setting affinity for a virtqueue
 * @vq: the virtqueue
 * @cpu: the cpu no.
 *
 * Pay attention the function are best-effort: the affinity hint may not be set
 * due to config support, irq type and sharing.
 *
 */
static inline
int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
{
	struct virtio_device *vdev = vq->vdev;
	if (vdev->config->set_vq_affinity)
		return vdev->config->set_vq_affinity(vq, cpu);
	return 0;
}

/* Memory accessors */
static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
{
	return __virtio16_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}

static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
{
	return __cpu_to_virtio16(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}

static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
{
	return __virtio32_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}

static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
{
	return __cpu_to_virtio32(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}

static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
{
	return __virtio64_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}

static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
{
	return __cpu_to_virtio64(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}

/* Config space accessors. */
#define virtio_cread(vdev, structname, member, ptr)			\
	do {								\
		/* Must match the member's type, and be integer */	\
		if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
			(*ptr) = 1;					\
									\
		switch (sizeof(*ptr)) {					\
		case 1:							\
			*(ptr) = virtio_cread8(vdev,			\
					       offsetof(structname, member)); \
			break;						\
		case 2:							\
			*(ptr) = virtio_cread16(vdev,			\
						offsetof(structname, member)); \
			break;						\
		case 4:							\
			*(ptr) = virtio_cread32(vdev,			\
						offsetof(structname, member)); \
			break;						\
		case 8:							\
			*(ptr) = virtio_cread64(vdev,			\
						offsetof(structname, member)); \
			break;						\
		default:						\
			BUG();						\
		}							\
	} while(0)

/* Config space accessors. */
#define virtio_cwrite(vdev, structname, member, ptr)			\
	do {								\
		/* Must match the member's type, and be integer */	\
		if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
			BUG_ON((*ptr) == 1);				\
									\
		switch (sizeof(*ptr)) {					\
		case 1:							\
			virtio_cwrite8(vdev,				\
				       offsetof(structname, member),	\
				       *(ptr));				\
			break;						\
		case 2:							\
			virtio_cwrite16(vdev,				\
					offsetof(structname, member),	\
					*(ptr));			\
			break;						\
		case 4:							\
			virtio_cwrite32(vdev,				\
					offsetof(structname, member),	\
					*(ptr));			\
			break;						\
		case 8:							\
			virtio_cwrite64(vdev,				\
					offsetof(structname, member),	\
					*(ptr));			\
			break;						\
		default:						\
			BUG();						\
		}							\
	} while(0)

static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
{
	u8 ret;
	vdev->config->get(vdev, offset, &ret, sizeof(ret));
	return ret;
}

/* Read @count fields, @bytes each. */
static inline void __virtio_cread_many(struct virtio_device *vdev,
				       unsigned int offset,
				       void *buf, size_t count, size_t bytes)
{
	u32 old, gen = vdev->config->generation ?
		vdev->config->generation(vdev) : 0;
	int i;

	do {
		old = gen;

		for (i = 0; i < count; i++)
			vdev->config->get(vdev, offset + bytes * i,
					  buf + i * bytes, bytes);

		gen = vdev->config->generation ?
			vdev->config->generation(vdev) : 0;
	} while (gen != old);
}


static inline void virtio_cread_bytes(struct virtio_device *vdev,
				      unsigned int offset,
				      void *buf, size_t len)
{
	__virtio_cread_many(vdev, offset, buf, len, 1);
}

static inline void virtio_cwrite8(struct virtio_device *vdev,
				  unsigned int offset, u8 val)
{
	vdev->config->set(vdev, offset, &val, sizeof(val));
}

static inline u16 virtio_cread16(struct virtio_device *vdev,
				 unsigned int offset)
{
	u16 ret;
	vdev->config->get(vdev, offset, &ret, sizeof(ret));
	return virtio16_to_cpu(vdev, (__force __virtio16)ret);
}

static inline void virtio_cwrite16(struct virtio_device *vdev,
				   unsigned int offset, u16 val)
{
	val = (__force u16)cpu_to_virtio16(vdev, val);
	vdev->config->set(vdev, offset, &val, sizeof(val));
}

static inline u32 virtio_cread32(struct virtio_device *vdev,
				 unsigned int offset)
{
	u32 ret;
	vdev->config->get(vdev, offset, &ret, sizeof(ret));
	return virtio32_to_cpu(vdev, (__force __virtio32)ret);
}

static inline void virtio_cwrite32(struct virtio_device *vdev,
				   unsigned int offset, u32 val)
{
	val = (__force u32)cpu_to_virtio32(vdev, val);
	vdev->config->set(vdev, offset, &val, sizeof(val));
}

static inline u64 virtio_cread64(struct virtio_device *vdev,
				 unsigned int offset)
{
	u64 ret;
	vdev->config->get(vdev, offset, &ret, sizeof(ret));
	__virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
	return virtio64_to_cpu(vdev, (__force __virtio64)ret);
}

static inline void virtio_cwrite64(struct virtio_device *vdev,
				   unsigned int offset, u64 val)
{
	val = (__force u64)cpu_to_virtio64(vdev, val);
	vdev->config->set(vdev, offset, &val, sizeof(val));
}

/* Conditional config space accessors. */
#define virtio_cread_feature(vdev, fbit, structname, member, ptr)	\
	({								\
		int _r = 0;						\
		if (!virtio_has_feature(vdev, fbit))			\
			_r = -ENOENT;					\
		else							\
			virtio_cread((vdev), structname, member, ptr);	\
		_r;							\
	})

#endif /* _LINUX_VIRTIO_CONFIG_H */