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 features. */ 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 /* Do we get callbacks when the ring is completely used, even if we've 19 * suppressed them? */ 20 #define VIRTIO_F_NOTIFY_ON_EMPTY 24 21 22 #ifdef __KERNEL__ 23 #include <linux/virtio.h> 24 25 /** 26 * virtio_config_ops - operations for configuring a virtio device 27 * @get: read the value of a configuration field 28 * vdev: the virtio_device 29 * offset: the offset of the configuration field 30 * buf: the buffer to write the field value into. 31 * len: the length of the buffer 32 * @set: write the value of a configuration field 33 * vdev: the virtio_device 34 * offset: the offset of the configuration field 35 * buf: the buffer to read the field value from. 36 * len: the length of the buffer 37 * @get_status: read the status byte 38 * vdev: the virtio_device 39 * Returns the status byte 40 * @set_status: write the status byte 41 * vdev: the virtio_device 42 * status: the new status byte 43 * @reset: reset the device 44 * vdev: the virtio device 45 * After this, status and feature negotiation must be done again 46 * @find_vq: find a virtqueue and instantiate it. 47 * vdev: the virtio_device 48 * index: the 0-based virtqueue number in case there's more than one. 49 * callback: the virqtueue callback 50 * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT). 51 * @del_vq: free a virtqueue found by find_vq(). 52 * @get_features: get the array of feature bits for this device. 53 * vdev: the virtio_device 54 * Returns the first 32 feature bits (all we currently need). 55 * @set_features: confirm what device features we'll be using. 56 * vdev: the virtio_device 57 * feature: the first 32 feature bits 58 */ 59 struct virtio_config_ops 60 { 61 void (*get)(struct virtio_device *vdev, unsigned offset, 62 void *buf, unsigned len); 63 void (*set)(struct virtio_device *vdev, unsigned offset, 64 const void *buf, unsigned len); 65 u8 (*get_status)(struct virtio_device *vdev); 66 void (*set_status)(struct virtio_device *vdev, u8 status); 67 void (*reset)(struct virtio_device *vdev); 68 struct virtqueue *(*find_vq)(struct virtio_device *vdev, 69 unsigned index, 70 void (*callback)(struct virtqueue *)); 71 void (*del_vq)(struct virtqueue *vq); 72 u32 (*get_features)(struct virtio_device *vdev); 73 void (*set_features)(struct virtio_device *vdev, u32 features); 74 }; 75 76 /* If driver didn't advertise the feature, it will never appear. */ 77 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 78 unsigned int fbit); 79 80 /** 81 * virtio_has_feature - helper to determine if this device has this feature. 82 * @vdev: the device 83 * @fbit: the feature bit 84 */ 85 static inline bool virtio_has_feature(const struct virtio_device *vdev, 86 unsigned int fbit) 87 { 88 /* Did you forget to fix assumptions on max features? */ 89 if (__builtin_constant_p(fbit)) 90 BUILD_BUG_ON(fbit >= 32); 91 92 virtio_check_driver_offered_feature(vdev, fbit); 93 return test_bit(fbit, vdev->features); 94 } 95 96 /** 97 * virtio_config_val - look for a feature and get a virtio config entry. 98 * @vdev: the virtio device 99 * @fbit: the feature bit 100 * @offset: the type to search for. 101 * @val: a pointer to the value to fill in. 102 * 103 * The return value is -ENOENT if the feature doesn't exist. Otherwise 104 * the config value is copied into whatever is pointed to by v. */ 105 #define virtio_config_val(vdev, fbit, offset, v) \ 106 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) 107 108 static inline int virtio_config_buf(struct virtio_device *vdev, 109 unsigned int fbit, 110 unsigned int offset, 111 void *buf, unsigned len) 112 { 113 if (!virtio_has_feature(vdev, fbit)) 114 return -ENOENT; 115 116 vdev->config->get(vdev, offset, buf, len); 117 return 0; 118 } 119 #endif /* __KERNEL__ */ 120 #endif /* _LINUX_VIRTIO_CONFIG_H */ 121