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 #ifdef __KERNEL__ 19 struct virtio_device; 20 21 /** 22 * virtio_config_ops - operations for configuring a virtio device 23 * @feature: search for a feature in this config 24 * vdev: the virtio_device 25 * bit: the feature bit 26 * Returns true if the feature is supported. Acknowledges the feature 27 * so the host can see it. 28 * @get: read the value of a configuration field 29 * vdev: the virtio_device 30 * offset: the offset of the configuration field 31 * buf: the buffer to write the field value into. 32 * len: the length of the buffer 33 * Note that contents are conventionally little-endian. 34 * @set: write the value of a configuration field 35 * vdev: the virtio_device 36 * offset: the offset of the configuration field 37 * buf: the buffer to read the field value from. 38 * len: the length of the buffer 39 * Note that contents are conventionally little-endian. 40 * @get_status: read the status byte 41 * vdev: the virtio_device 42 * Returns the status byte 43 * @set_status: write the status byte 44 * vdev: the virtio_device 45 * status: the new status byte 46 * @reset: reset the device 47 * vdev: the virtio device 48 * After this, status and feature negotiation must be done again 49 * @find_vq: find a virtqueue and instantiate it. 50 * vdev: the virtio_device 51 * index: the 0-based virtqueue number in case there's more than one. 52 * callback: the virqtueue callback 53 * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT). 54 * @del_vq: free a virtqueue found by find_vq(). 55 */ 56 struct virtio_config_ops 57 { 58 bool (*feature)(struct virtio_device *vdev, unsigned bit); 59 void (*get)(struct virtio_device *vdev, unsigned offset, 60 void *buf, unsigned len); 61 void (*set)(struct virtio_device *vdev, unsigned offset, 62 const void *buf, unsigned len); 63 u8 (*get_status)(struct virtio_device *vdev); 64 void (*set_status)(struct virtio_device *vdev, u8 status); 65 void (*reset)(struct virtio_device *vdev); 66 struct virtqueue *(*find_vq)(struct virtio_device *vdev, 67 unsigned index, 68 void (*callback)(struct virtqueue *)); 69 void (*del_vq)(struct virtqueue *vq); 70 }; 71 72 /** 73 * virtio_config_val - look for a feature and get a single virtio config. 74 * @vdev: the virtio device 75 * @fbit: the feature bit 76 * @offset: the type to search for. 77 * @val: a pointer to the value to fill in. 78 * 79 * The return value is -ENOENT if the feature doesn't exist. Otherwise 80 * the value is endian-corrected and returned in v. */ 81 #define virtio_config_val(vdev, fbit, offset, v) ({ \ 82 int _err; \ 83 if ((vdev)->config->feature((vdev), (fbit))) { \ 84 __virtio_config_val((vdev), (offset), (v)); \ 85 _err = 0; \ 86 } else \ 87 _err = -ENOENT; \ 88 _err; \ 89 }) 90 91 /** 92 * __virtio_config_val - get a single virtio config without feature check. 93 * @vdev: the virtio device 94 * @offset: the type to search for. 95 * @val: a pointer to the value to fill in. 96 * 97 * The value is endian-corrected and returned in v. */ 98 #define __virtio_config_val(vdev, offset, v) do { \ 99 BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \ 100 && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \ 101 (vdev)->config->get((vdev), (offset), (v), sizeof(*(v))); \ 102 switch (sizeof(*(v))) { \ 103 case 2: le16_to_cpus((__u16 *) v); break; \ 104 case 4: le32_to_cpus((__u32 *) v); break; \ 105 case 8: le64_to_cpus((__u64 *) v); break; \ 106 } \ 107 } while(0) 108 #endif /* __KERNEL__ */ 109 #endif /* _LINUX_VIRTIO_CONFIG_H */ 110