#ifndef _LINUX_VIRTIO_CONFIG_H #define _LINUX_VIRTIO_CONFIG_H /* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so * anyone can use the definitions to implement compatible drivers/servers. */ /* Virtio devices use a standardized configuration space to define their * features and pass configuration information, but each implementation can * store and access that space differently. */ #include <linux/types.h> /* Status byte for guest to report progress, and synchronize features. */ /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 /* We have found a driver for the device. */ #define VIRTIO_CONFIG_S_DRIVER 2 /* Driver has used its parts of the config, and is happy */ #define VIRTIO_CONFIG_S_DRIVER_OK 4 /* We've given up on this device. */ #define VIRTIO_CONFIG_S_FAILED 0x80 /* Some virtio feature bits (currently bits 28 through 31) are reserved for the * transport being used (eg. virtio_ring), the rest are per-device feature * bits. */ #define VIRTIO_TRANSPORT_F_START 28 #define VIRTIO_TRANSPORT_F_END 32 /* Do we get callbacks when the ring is completely used, even if we've * suppressed them? */ #define VIRTIO_F_NOTIFY_ON_EMPTY 24 #ifdef __KERNEL__ #include <linux/virtio.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 * @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 * @find_vq: find a virtqueue and instantiate it. * vdev: the virtio_device * index: the 0-based virtqueue number in case there's more than one. * callback: the virqtueue callback * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT). * @del_vq: free a virtqueue found by find_vq(). * @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. */ 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); u8 (*get_status)(struct virtio_device *vdev); void (*set_status)(struct virtio_device *vdev, u8 status); void (*reset)(struct virtio_device *vdev); struct virtqueue *(*find_vq)(struct virtio_device *vdev, unsigned index, void (*callback)(struct virtqueue *)); void (*del_vq)(struct virtqueue *vq); u32 (*get_features)(struct virtio_device *vdev); void (*finalize_features)(struct virtio_device *vdev); }; /* 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_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) { /* Did you forget to fix assumptions on max features? */ if (__builtin_constant_p(fbit)) BUILD_BUG_ON(fbit >= 32); virtio_check_driver_offered_feature(vdev, fbit); return test_bit(fbit, vdev->features); } /** * virtio_config_val - look for a feature and get a virtio config entry. * @vdev: the virtio device * @fbit: the feature bit * @offset: the type to search for. * @val: a pointer to the value to fill in. * * The return value is -ENOENT if the feature doesn't exist. Otherwise * the config value is copied into whatever is pointed to by v. */ #define virtio_config_val(vdev, fbit, offset, v) \ virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) static inline int virtio_config_buf(struct virtio_device *vdev, unsigned int fbit, unsigned int offset, void *buf, unsigned len) { if (!virtio_has_feature(vdev, fbit)) return -ENOENT; vdev->config->get(vdev, offset, buf, len); return 0; } #endif /* __KERNEL__ */ #endif /* _LINUX_VIRTIO_CONFIG_H */