1 #ifndef _LINUX_VIRTIO_CONFIG_H 2 #define _LINUX_VIRTIO_CONFIG_H 3 /* Virtio devices use a standardized configuration space to define their 4 * features and pass configuration information, but each implementation can 5 * store and access that space differently. */ 6 #include <linux/types.h> 7 8 /* Status byte for guest to report progress, and synchronize config. */ 9 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ 10 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 11 /* We have found a driver for the device. */ 12 #define VIRTIO_CONFIG_S_DRIVER 2 13 /* Driver has used its parts of the config, and is happy */ 14 #define VIRTIO_CONFIG_S_DRIVER_OK 4 15 /* We've given up on this device. */ 16 #define VIRTIO_CONFIG_S_FAILED 0x80 17 18 /* Feature byte (actually 7 bits availabe): */ 19 /* Requirements/features of the virtio implementation. */ 20 #define VIRTIO_CONFIG_F_VIRTIO 1 21 /* Requirements/features of the virtqueue (may have more than one). */ 22 #define VIRTIO_CONFIG_F_VIRTQUEUE 2 23 24 #ifdef __KERNEL__ 25 struct virtio_device; 26 27 /** 28 * virtio_config_ops - operations for configuring a virtio device 29 * @find: search for the next configuration field of the given type. 30 * vdev: the virtio_device 31 * type: the feature type 32 * len: the (returned) length of the field if found. 33 * Returns a token if found, or NULL. Never returnes the same field twice 34 * (ie. it's used up). 35 * @get: read the value of a configuration field after find(). 36 * vdev: the virtio_device 37 * token: the token returned from find(). 38 * buf: the buffer to write the field value into. 39 * len: the length of the buffer (given by find()). 40 * Note that contents are conventionally little-endian. 41 * @set: write the value of a configuration field after find(). 42 * vdev: the virtio_device 43 * token: the token returned from find(). 44 * buf: the buffer to read the field value from. 45 * len: the length of the buffer (given by find()). 46 * Note that contents are conventionally little-endian. 47 * @get_status: read the status byte 48 * vdev: the virtio_device 49 * Returns the status byte 50 * @set_status: write the status byte 51 * vdev: the virtio_device 52 * status: the new status byte 53 * @find_vq: find the first VIRTIO_CONFIG_F_VIRTQUEUE and create a virtqueue. 54 * vdev: the virtio_device 55 * callback: the virqtueue callback 56 * Returns the new virtqueue or ERR_PTR(). 57 * @del_vq: free a virtqueue found by find_vq(). 58 */ 59 struct virtio_config_ops 60 { 61 void *(*find)(struct virtio_device *vdev, u8 type, unsigned *len); 62 void (*get)(struct virtio_device *vdev, void *token, 63 void *buf, unsigned len); 64 void (*set)(struct virtio_device *vdev, void *token, 65 const void *buf, unsigned len); 66 u8 (*get_status)(struct virtio_device *vdev); 67 void (*set_status)(struct virtio_device *vdev, u8 status); 68 struct virtqueue *(*find_vq)(struct virtio_device *vdev, 69 bool (*callback)(struct virtqueue *)); 70 void (*del_vq)(struct virtqueue *vq); 71 }; 72 73 /** 74 * virtio_config_val - get a single virtio config and mark it used. 75 * @config: the virtio config space 76 * @type: the type to search for. 77 * @val: a pointer to the value to fill in. 78 * 79 * Once used, the config type is marked with VIRTIO_CONFIG_F_USED so it can't 80 * be found again. This version does endian conversion. */ 81 #define virtio_config_val(vdev, type, v) ({ \ 82 int _err = __virtio_config_val((vdev),(type),(v),sizeof(*(v))); \ 83 \ 84 BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \ 85 && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \ 86 if (!_err) { \ 87 switch (sizeof(*(v))) { \ 88 case 2: le16_to_cpus((__u16 *) v); break; \ 89 case 4: le32_to_cpus((__u32 *) v); break; \ 90 case 8: le64_to_cpus((__u64 *) v); break; \ 91 } \ 92 } \ 93 _err; \ 94 }) 95 96 int __virtio_config_val(struct virtio_device *dev, 97 u8 type, void *val, size_t size); 98 99 /** 100 * virtio_use_bit - helper to use a feature bit in a bitfield value. 101 * @dev: the virtio device 102 * @token: the token as returned from vdev->config->find(). 103 * @len: the length of the field. 104 * @bitnum: the bit to test. 105 * 106 * If handed a NULL token, it returns false, otherwise returns bit status. 107 * If it's one, it sets the mirroring acknowledgement bit. */ 108 int virtio_use_bit(struct virtio_device *vdev, 109 void *token, unsigned int len, unsigned int bitnum); 110 #endif /* __KERNEL__ */ 111 #endif /* _LINUX_VIRTIO_CONFIG_H */ 112