1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
4 * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
5 *
6 * VirtIO is a virtualization standard for network and disk device drivers
7 * where just the guest's device driver "knows" it is running in a virtual
8 * environment, and cooperates with the hypervisor. This enables guests to
9 * get high performance network and disk operations, and gives most of the
10 * performance benefits of paravirtualization. In the U-Boot case, the guest
11 * is U-Boot itself, while the virtual environment are normally QEMU targets
12 * like ARM, RISC-V and x86.
13 *
14 * See http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf for
15 * the VirtIO specification v1.0.
16 *
17 * This file is largely based on Linux kernel virtio_*.h files
18 */
19
20 #ifndef __VIRTIO_H__
21 #define __VIRTIO_H__
22
23 #include <virtio_types.h>
24 #include <linux/bitops.h>
25 #include <linux/bug.h>
26 #define VIRTIO_ID_NET 1 /* virtio net */
27 #define VIRTIO_ID_BLOCK 2 /* virtio block */
28 #define VIRTIO_ID_RNG 4 /* virtio rng */
29 #define VIRTIO_ID_MAX_NUM 5
30
31 #define VIRTIO_NET_DRV_NAME "virtio-net"
32 #define VIRTIO_BLK_DRV_NAME "virtio-blk"
33 #define VIRTIO_RNG_DRV_NAME "virtio-rng"
34
35 /* Status byte for guest to report progress, and synchronize features */
36
37 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
38 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
39 /* We have found a driver for the device */
40 #define VIRTIO_CONFIG_S_DRIVER 2
41 /* Driver has used its parts of the config, and is happy */
42 #define VIRTIO_CONFIG_S_DRIVER_OK 4
43 /* Driver has finished configuring features */
44 #define VIRTIO_CONFIG_S_FEATURES_OK 8
45 /* Device entered invalid state, driver must reset it */
46 #define VIRTIO_CONFIG_S_NEEDS_RESET 0x40
47 /* We've given up on this device */
48 #define VIRTIO_CONFIG_S_FAILED 0x80
49
50 /*
51 * Virtio feature bits VIRTIO_TRANSPORT_F_START through VIRTIO_TRANSPORT_F_END
52 * are reserved for the transport being used (eg: virtio_ring, virtio_pci etc.),
53 * the rest are per-device feature bits.
54 */
55 #define VIRTIO_TRANSPORT_F_START 28
56 #define VIRTIO_TRANSPORT_F_END 38
57
58 #ifndef VIRTIO_CONFIG_NO_LEGACY
59 /*
60 * Do we get callbacks when the ring is completely used,
61 * even if we've suppressed them?
62 */
63 #define VIRTIO_F_NOTIFY_ON_EMPTY 24
64
65 /* Can the device handle any descriptor layout? */
66 #define VIRTIO_F_ANY_LAYOUT 27
67 #endif /* VIRTIO_CONFIG_NO_LEGACY */
68
69 /* v1.0 compliant */
70 #define VIRTIO_F_VERSION_1 32
71
72 /*
73 * If clear - device has the IOMMU bypass quirk feature.
74 * If set - use platform tools to detect the IOMMU.
75 *
76 * Note the reverse polarity (compared to most other features),
77 * this is for compatibility with legacy systems.
78 */
79 #define VIRTIO_F_IOMMU_PLATFORM 33
80
81 /* Does the device support Single Root I/O Virtualization? */
82 #define VIRTIO_F_SR_IOV 37
83
84 /**
85 * virtio scatter-gather struct
86 *
87 * @addr: sg buffer address
88 * @lengh: sg buffer length
89 */
90 struct virtio_sg {
91 void *addr;
92 size_t length;
93 };
94
95 struct virtqueue;
96
97 /* virtio bus operations */
98 struct dm_virtio_ops {
99 /**
100 * get_config() - read the value of a configuration field
101 *
102 * @vdev: the real virtio device
103 * @offset: the offset of the configuration field
104 * @buf: the buffer to write the field value into
105 * @len: the length of the buffer
106 * @return 0 if OK, -ve on error
107 */
108 int (*get_config)(struct udevice *vdev, unsigned int offset,
109 void *buf, unsigned int len);
110 /**
111 * set_config() - write the value of a configuration field
112 *
113 * @vdev: the real virtio device
114 * @offset: the offset of the configuration field
115 * @buf: the buffer to read the field value from
116 * @len: the length of the buffer
117 * @return 0 if OK, -ve on error
118 */
119 int (*set_config)(struct udevice *vdev, unsigned int offset,
120 const void *buf, unsigned int len);
121 /**
122 * generation() - config generation counter
123 *
124 * @vdev: the real virtio device
125 * @counter: the returned config generation counter
126 * @return 0 if OK, -ve on error
127 */
128 int (*generation)(struct udevice *vdev, u32 *counter);
129 /**
130 * get_status() - read the status byte
131 *
132 * @vdev: the real virtio device
133 * @status: the returned status byte
134 * @return 0 if OK, -ve on error
135 */
136 int (*get_status)(struct udevice *vdev, u8 *status);
137 /**
138 * set_status() - write the status byte
139 *
140 * @vdev: the real virtio device
141 * @status: the new status byte
142 * @return 0 if OK, -ve on error
143 */
144 int (*set_status)(struct udevice *vdev, u8 status);
145 /**
146 * reset() - reset the device
147 *
148 * @vdev: the real virtio device
149 * @return 0 if OK, -ve on error
150 */
151 int (*reset)(struct udevice *vdev);
152 /**
153 * get_features() - get the array of feature bits for this device
154 *
155 * @vdev: the real virtio device
156 * @features: the first 32 feature bits (all we currently need)
157 * @return 0 if OK, -ve on error
158 */
159 int (*get_features)(struct udevice *vdev, u64 *features);
160 /**
161 * set_features() - confirm what device features we'll be using
162 *
163 * @vdev: the real virtio device
164 * @return 0 if OK, -ve on error
165 */
166 int (*set_features)(struct udevice *vdev);
167 /**
168 * find_vqs() - find virtqueues and instantiate them
169 *
170 * @vdev: the real virtio device
171 * @nvqs: the number of virtqueues to find
172 * @vqs: on success, includes new virtqueues
173 * @return 0 if OK, -ve on error
174 */
175 int (*find_vqs)(struct udevice *vdev, unsigned int nvqs,
176 struct virtqueue *vqs[]);
177 /**
178 * del_vqs() - free virtqueues found by find_vqs()
179 *
180 * @vdev: the real virtio device
181 * @return 0 if OK, -ve on error
182 */
183 int (*del_vqs)(struct udevice *vdev);
184 /**
185 * notify() - notify the device to process the queue
186 *
187 * @vdev: the real virtio device
188 * @vq: virtqueue to process
189 * @return 0 if OK, -ve on error
190 */
191 int (*notify)(struct udevice *vdev, struct virtqueue *vq);
192 };
193
194 /* Get access to a virtio bus' operations */
195 #define virtio_get_ops(dev) ((struct dm_virtio_ops *)(dev)->driver->ops)
196
197 /**
198 * virtio uclass per device private data
199 *
200 * @vqs: virtualqueue for the virtio device
201 * @vdev: the real virtio device underneath
202 * @legacy: is it a legacy device?
203 * @device: virtio device ID
204 * @vendor: virtio vendor ID
205 * @features: negotiated supported features
206 * @feature_table: an array of feature supported by the driver
207 * @feature_table_size: number of entries in the feature table array
208 * @feature_table_legacy: same as feature_table but working in legacy mode
209 * @feature_table_size_legacy: number of entries in feature table legacy array
210 */
211 struct virtio_dev_priv {
212 struct list_head vqs;
213 struct udevice *vdev;
214 bool legacy;
215 u32 device;
216 u32 vendor;
217 u64 features;
218 const u32 *feature_table;
219 u32 feature_table_size;
220 const u32 *feature_table_legacy;
221 u32 feature_table_size_legacy;
222 };
223
224 /**
225 * virtio_get_config() - read the value of a configuration field
226 *
227 * @vdev: the real virtio device
228 * @offset: the offset of the configuration field
229 * @buf: the buffer to write the field value into
230 * @len: the length of the buffer
231 * Return: 0 if OK, -ve on error
232 */
233 int virtio_get_config(struct udevice *vdev, unsigned int offset,
234 void *buf, unsigned int len);
235
236 /**
237 * virtio_set_config() - write the value of a configuration field
238 *
239 * @vdev: the real virtio device
240 * @offset: the offset of the configuration field
241 * @buf: the buffer to read the field value from
242 * @len: the length of the buffer
243 * Return: 0 if OK, -ve on error
244 */
245 int virtio_set_config(struct udevice *vdev, unsigned int offset,
246 void *buf, unsigned int len);
247
248 /**
249 * virtio_generation() - config generation counter
250 *
251 * @vdev: the real virtio device
252 * @counter: the returned config generation counter
253 * Return: 0 if OK, -ve on error
254 */
255 int virtio_generation(struct udevice *vdev, u32 *counter);
256
257 /**
258 * virtio_get_status() - read the status byte
259 *
260 * @vdev: the real virtio device
261 * @status: the returned status byte
262 * Return: 0 if OK, -ve on error
263 */
264 int virtio_get_status(struct udevice *vdev, u8 *status);
265
266 /**
267 * virtio_set_status() - write the status byte
268 *
269 * @vdev: the real virtio device
270 * @status: the new status byte
271 * Return: 0 if OK, -ve on error
272 */
273 int virtio_set_status(struct udevice *vdev, u8 status);
274
275 /**
276 * virtio_reset() - reset the device
277 *
278 * @vdev: the real virtio device
279 * Return: 0 if OK, -ve on error
280 */
281 int virtio_reset(struct udevice *vdev);
282
283 /**
284 * virtio_get_features() - get the array of feature bits for this device
285 *
286 * @vdev: the real virtio device
287 * @features: the first 32 feature bits (all we currently need)
288 * Return: 0 if OK, -ve on error
289 */
290 int virtio_get_features(struct udevice *vdev, u64 *features);
291
292 /**
293 * virtio_set_features() - confirm what device features we'll be using
294 *
295 * @vdev: the real virtio device
296 * Return: 0 if OK, -ve on error
297 */
298 int virtio_set_features(struct udevice *vdev);
299
300 /**
301 * virtio_find_vqs() - find virtqueues and instantiate them
302 *
303 * @vdev: the real virtio device
304 * @nvqs: the number of virtqueues to find
305 * @vqs: on success, includes new virtqueues
306 * Return: 0 if OK, -ve on error
307 */
308 int virtio_find_vqs(struct udevice *vdev, unsigned int nvqs,
309 struct virtqueue *vqs[]);
310
311 /**
312 * virtio_del_vqs() - free virtqueues found by find_vqs()
313 *
314 * @vdev: the real virtio device
315 * Return: 0 if OK, -ve on error
316 */
317 int virtio_del_vqs(struct udevice *vdev);
318
319 /**
320 * virtio_notify() - notify the device to process the queue
321 *
322 * @vdev: the real virtio device
323 * @vq: virtqueue to process
324 * Return: 0 if OK, -ve on error
325 */
326 int virtio_notify(struct udevice *vdev, struct virtqueue *vq);
327
328 /**
329 * virtio_add_status() - helper to set a new status code to the device
330 *
331 * @vdev: the real virtio device
332 * @status: new status code to be added
333 */
334 void virtio_add_status(struct udevice *vdev, u8 status);
335
336 /**
337 * virtio_finalize_features() - helper to finalize features
338 *
339 * @vdev: the real virtio device
340 * Return: 0 if OK, -ve on error
341 */
342 int virtio_finalize_features(struct udevice *vdev);
343
344 /**
345 * virtio_driver_features_init() - initialize driver supported features
346 *
347 * This fills in the virtio device parent per child private data with the given
348 * information, which contains driver supported features and legacy features.
349 *
350 * This API should be called in the virtio device driver's bind method, so that
351 * later virtio transport uclass driver can utilize the driver supplied features
352 * to negotiate with the device on the final supported features.
353 *
354 * @priv: virtio uclass per device private data
355 * @feature: an array of feature supported by the driver
356 * @feature_size: number of entries in the feature table array
357 * @feature_legacy: same as feature_table but working in legacy mode
358 * @feature_legacy_size:number of entries in feature table legacy array
359 */
360 void virtio_driver_features_init(struct virtio_dev_priv *priv,
361 const u32 *feature,
362 u32 feature_size,
363 const u32 *feature_legacy,
364 u32 feature_legacy_size);
365
366 /**
367 * virtio_init() - helper to enumerate all known virtio devices
368 *
369 * Return: 0 if OK, -ve on error
370 */
371 int virtio_init(void);
372
__virtio16_to_cpu(bool little_endian,__virtio16 val)373 static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val)
374 {
375 if (little_endian)
376 return le16_to_cpu((__force __le16)val);
377 else
378 return be16_to_cpu((__force __be16)val);
379 }
380
__cpu_to_virtio16(bool little_endian,u16 val)381 static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val)
382 {
383 if (little_endian)
384 return (__force __virtio16)cpu_to_le16(val);
385 else
386 return (__force __virtio16)cpu_to_be16(val);
387 }
388
__virtio32_to_cpu(bool little_endian,__virtio32 val)389 static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val)
390 {
391 if (little_endian)
392 return le32_to_cpu((__force __le32)val);
393 else
394 return be32_to_cpu((__force __be32)val);
395 }
396
__cpu_to_virtio32(bool little_endian,u32 val)397 static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val)
398 {
399 if (little_endian)
400 return (__force __virtio32)cpu_to_le32(val);
401 else
402 return (__force __virtio32)cpu_to_be32(val);
403 }
404
__virtio64_to_cpu(bool little_endian,__virtio64 val)405 static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val)
406 {
407 if (little_endian)
408 return le64_to_cpu((__force __le64)val);
409 else
410 return be64_to_cpu((__force __be64)val);
411 }
412
__cpu_to_virtio64(bool little_endian,u64 val)413 static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val)
414 {
415 if (little_endian)
416 return (__force __virtio64)cpu_to_le64(val);
417 else
418 return (__force __virtio64)cpu_to_be64(val);
419 }
420
421 /**
422 * __virtio_test_bit - helper to test feature bits
423 *
424 * For use by transports. Devices should normally use virtio_has_feature,
425 * which includes more checks.
426 *
427 * @udev: the transport device
428 * @fbit: the feature bit
429 */
__virtio_test_bit(struct udevice * udev,unsigned int fbit)430 static inline bool __virtio_test_bit(struct udevice *udev, unsigned int fbit)
431 {
432 struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
433
434 /* Did you forget to fix assumptions on max features? */
435 if (__builtin_constant_p(fbit))
436 BUILD_BUG_ON(fbit >= 64);
437 else
438 WARN_ON(fbit >= 64);
439
440 return uc_priv->features & BIT_ULL(fbit);
441 }
442
443 /**
444 * __virtio_set_bit - helper to set feature bits
445 *
446 * For use by transports.
447 *
448 * @udev: the transport device
449 * @fbit: the feature bit
450 */
__virtio_set_bit(struct udevice * udev,unsigned int fbit)451 static inline void __virtio_set_bit(struct udevice *udev, unsigned int fbit)
452 {
453 struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
454
455 /* Did you forget to fix assumptions on max features? */
456 if (__builtin_constant_p(fbit))
457 BUILD_BUG_ON(fbit >= 64);
458 else
459 WARN_ON(fbit >= 64);
460
461 uc_priv->features |= BIT_ULL(fbit);
462 }
463
464 /**
465 * __virtio_clear_bit - helper to clear feature bits
466 *
467 * For use by transports.
468 *
469 * @vdev: the transport device
470 * @fbit: the feature bit
471 */
__virtio_clear_bit(struct udevice * udev,unsigned int fbit)472 static inline void __virtio_clear_bit(struct udevice *udev, unsigned int fbit)
473 {
474 struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(udev);
475
476 /* Did you forget to fix assumptions on max features? */
477 if (__builtin_constant_p(fbit))
478 BUILD_BUG_ON(fbit >= 64);
479 else
480 WARN_ON(fbit >= 64);
481
482 uc_priv->features &= ~BIT_ULL(fbit);
483 }
484
485 /**
486 * virtio_has_feature - helper to determine if this device has this feature
487 *
488 * Note this API is only usable after the virtio device driver's bind phase,
489 * as the feature has been negotiated between the device and the driver.
490 *
491 * @vdev: the virtio device
492 * @fbit: the feature bit
493 */
virtio_has_feature(struct udevice * vdev,unsigned int fbit)494 static inline bool virtio_has_feature(struct udevice *vdev, unsigned int fbit)
495 {
496 if (!(dev_get_flags(vdev) & DM_FLAG_BOUND))
497 WARN_ON(true);
498
499 return __virtio_test_bit(vdev->parent, fbit);
500 }
501
virtio_legacy_is_little_endian(void)502 static inline bool virtio_legacy_is_little_endian(void)
503 {
504 #ifdef __LITTLE_ENDIAN
505 return true;
506 #else
507 return false;
508 #endif
509 }
510
virtio_is_little_endian(struct udevice * vdev)511 static inline bool virtio_is_little_endian(struct udevice *vdev)
512 {
513 struct virtio_dev_priv *uc_priv = dev_get_uclass_priv(vdev->parent);
514
515 return !uc_priv->legacy || virtio_legacy_is_little_endian();
516 }
517
518 /* Memory accessors */
virtio16_to_cpu(struct udevice * vdev,__virtio16 val)519 static inline u16 virtio16_to_cpu(struct udevice *vdev, __virtio16 val)
520 {
521 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
522 }
523
cpu_to_virtio16(struct udevice * vdev,u16 val)524 static inline __virtio16 cpu_to_virtio16(struct udevice *vdev, u16 val)
525 {
526 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
527 }
528
virtio32_to_cpu(struct udevice * vdev,__virtio32 val)529 static inline u32 virtio32_to_cpu(struct udevice *vdev, __virtio32 val)
530 {
531 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
532 }
533
cpu_to_virtio32(struct udevice * vdev,u32 val)534 static inline __virtio32 cpu_to_virtio32(struct udevice *vdev, u32 val)
535 {
536 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
537 }
538
virtio64_to_cpu(struct udevice * vdev,__virtio64 val)539 static inline u64 virtio64_to_cpu(struct udevice *vdev, __virtio64 val)
540 {
541 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
542 }
543
cpu_to_virtio64(struct udevice * vdev,u64 val)544 static inline __virtio64 cpu_to_virtio64(struct udevice *vdev, u64 val)
545 {
546 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
547 }
548
549 /* Read @count fields, @bytes each */
__virtio_cread_many(struct udevice * vdev,unsigned int offset,void * buf,size_t count,size_t bytes)550 static inline void __virtio_cread_many(struct udevice *vdev,
551 unsigned int offset,
552 void *buf, size_t count, size_t bytes)
553 {
554 u32 old, gen;
555 int i;
556
557 /* no need to check return value as generation can be optional */
558 virtio_generation(vdev, &gen);
559 do {
560 old = gen;
561
562 for (i = 0; i < count; i++)
563 virtio_get_config(vdev, offset + bytes * i,
564 buf + i * bytes, bytes);
565
566 virtio_generation(vdev, &gen);
567 } while (gen != old);
568 }
569
virtio_cread_bytes(struct udevice * vdev,unsigned int offset,void * buf,size_t len)570 static inline void virtio_cread_bytes(struct udevice *vdev,
571 unsigned int offset,
572 void *buf, size_t len)
573 {
574 __virtio_cread_many(vdev, offset, buf, len, 1);
575 }
576
virtio_cread8(struct udevice * vdev,unsigned int offset)577 static inline u8 virtio_cread8(struct udevice *vdev, unsigned int offset)
578 {
579 u8 ret;
580
581 virtio_get_config(vdev, offset, &ret, sizeof(ret));
582 return ret;
583 }
584
virtio_cwrite8(struct udevice * vdev,unsigned int offset,u8 val)585 static inline void virtio_cwrite8(struct udevice *vdev,
586 unsigned int offset, u8 val)
587 {
588 virtio_set_config(vdev, offset, &val, sizeof(val));
589 }
590
virtio_cread16(struct udevice * vdev,unsigned int offset)591 static inline u16 virtio_cread16(struct udevice *vdev,
592 unsigned int offset)
593 {
594 u16 ret;
595
596 virtio_get_config(vdev, offset, &ret, sizeof(ret));
597 return virtio16_to_cpu(vdev, (__force __virtio16)ret);
598 }
599
virtio_cwrite16(struct udevice * vdev,unsigned int offset,u16 val)600 static inline void virtio_cwrite16(struct udevice *vdev,
601 unsigned int offset, u16 val)
602 {
603 val = (__force u16)cpu_to_virtio16(vdev, val);
604 virtio_set_config(vdev, offset, &val, sizeof(val));
605 }
606
virtio_cread32(struct udevice * vdev,unsigned int offset)607 static inline u32 virtio_cread32(struct udevice *vdev,
608 unsigned int offset)
609 {
610 u32 ret;
611
612 virtio_get_config(vdev, offset, &ret, sizeof(ret));
613 return virtio32_to_cpu(vdev, (__force __virtio32)ret);
614 }
615
virtio_cwrite32(struct udevice * vdev,unsigned int offset,u32 val)616 static inline void virtio_cwrite32(struct udevice *vdev,
617 unsigned int offset, u32 val)
618 {
619 val = (__force u32)cpu_to_virtio32(vdev, val);
620 virtio_set_config(vdev, offset, &val, sizeof(val));
621 }
622
virtio_cread64(struct udevice * vdev,unsigned int offset)623 static inline u64 virtio_cread64(struct udevice *vdev,
624 unsigned int offset)
625 {
626 u64 ret;
627
628 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
629 return virtio64_to_cpu(vdev, (__force __virtio64)ret);
630 }
631
virtio_cwrite64(struct udevice * vdev,unsigned int offset,u64 val)632 static inline void virtio_cwrite64(struct udevice *vdev,
633 unsigned int offset, u64 val)
634 {
635 val = (__force u64)cpu_to_virtio64(vdev, val);
636 virtio_set_config(vdev, offset, &val, sizeof(val));
637 }
638
639 /* Config space read accessor */
640 #define virtio_cread(vdev, structname, member, ptr) \
641 do { \
642 /* Must match the member's type, and be integer */ \
643 if (!typecheck(typeof((((structname *)0)->member)), *(ptr))) \
644 (*ptr) = 1; \
645 \
646 switch (sizeof(*ptr)) { \
647 case 1: \
648 *(ptr) = virtio_cread8(vdev, \
649 offsetof(structname, member)); \
650 break; \
651 case 2: \
652 *(ptr) = virtio_cread16(vdev, \
653 offsetof(structname, member)); \
654 break; \
655 case 4: \
656 *(ptr) = virtio_cread32(vdev, \
657 offsetof(structname, member)); \
658 break; \
659 case 8: \
660 *(ptr) = virtio_cread64(vdev, \
661 offsetof(structname, member)); \
662 break; \
663 default: \
664 WARN_ON(true); \
665 } \
666 } while (0)
667
668 /* Config space write accessor */
669 #define virtio_cwrite(vdev, structname, member, ptr) \
670 do { \
671 /* Must match the member's type, and be integer */ \
672 if (!typecheck(typeof((((structname *)0)->member)), *(ptr))) \
673 WARN_ON((*ptr) == 1); \
674 \
675 switch (sizeof(*ptr)) { \
676 case 1: \
677 virtio_cwrite8(vdev, \
678 offsetof(structname, member), \
679 *(ptr)); \
680 break; \
681 case 2: \
682 virtio_cwrite16(vdev, \
683 offsetof(structname, member), \
684 *(ptr)); \
685 break; \
686 case 4: \
687 virtio_cwrite32(vdev, \
688 offsetof(structname, member), \
689 *(ptr)); \
690 break; \
691 case 8: \
692 virtio_cwrite64(vdev, \
693 offsetof(structname, member), \
694 *(ptr)); \
695 break; \
696 default: \
697 WARN_ON(true); \
698 } \
699 } while (0)
700
701 /* Conditional config space accessors */
702 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
703 ({ \
704 int _r = 0; \
705 if (!virtio_has_feature(vdev, fbit)) \
706 _r = -ENOENT; \
707 else \
708 virtio_cread(vdev, structname, member, ptr); \
709 _r; \
710 })
711
712 #endif /* __VIRTIO_H__ */
713