[linux-2.6-block.git] / include / linux / virtio_config.h

#ifndef _LINUX_VIRTIO_CONFIG_H
#define _LINUX_VIRTIO_CONFIG_H
/* 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 config. */
/* 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

/* Feature byte (actually 7 bits availabe): */
/* Requirements/features of the virtio implementation. */
#define VIRTIO_CONFIG_F_VIRTIO 1
/* Requirements/features of the virtqueue (may have more than one). */
#define VIRTIO_CONFIG_F_VIRTQUEUE 2

#ifdef __KERNEL__
struct virtio_device;

/**
 * virtio_config_ops - operations for configuring a virtio device
 * @find: search for the next configuration field of the given type.
 *	vdev: the virtio_device
 *	type: the feature type
 *	len: the (returned) length of the field if found.
 *	Returns a token if found, or NULL.  Never returnes the same field twice
 *	(ie. it's used up).
 * @get: read the value of a configuration field after find().
 *	vdev: the virtio_device
 *	token: the token returned from find().
 *	buf: the buffer to write the field value into.
 *	len: the length of the buffer (given by find()).
 *	Note that contents are conventionally little-endian.
 * @set: write the value of a configuration field after find().
 *	vdev: the virtio_device
 *	token: the token returned from find().
 *	buf: the buffer to read the field value from.
 *	len: the length of the buffer (given by find()).
 *	Note that contents are conventionally little-endian.
 * @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
 * @find_vq: find the first VIRTIO_CONFIG_F_VIRTQUEUE and create a virtqueue.
 *	vdev: the virtio_device
 *	callback: the virqtueue callback
 *	Returns the new virtqueue or ERR_PTR().
 * @del_vq: free a virtqueue found by find_vq().
 */
struct virtio_config_ops
{
	void *(*find)(struct virtio_device *vdev, u8 type, unsigned *len);
	void (*get)(struct virtio_device *vdev, void *token,
		    void *buf, unsigned len);
	void (*set)(struct virtio_device *vdev, void *token,
		    const void *buf, unsigned len);
	u8 (*get_status)(struct virtio_device *vdev);
	void (*set_status)(struct virtio_device *vdev, u8 status);
	struct virtqueue *(*find_vq)(struct virtio_device *vdev,
				     bool (*callback)(struct virtqueue *));
	void (*del_vq)(struct virtqueue *vq);
};

/**
 * virtio_config_val - get a single virtio config and mark it used.
 * @config: the virtio config space
 * @type: the type to search for.
 * @val: a pointer to the value to fill in.
 *
 * Once used, the config type is marked with VIRTIO_CONFIG_F_USED so it can't
 * be found again.  This version does endian conversion. */
#define virtio_config_val(vdev, type, v) ({				\
	int _err = __virtio_config_val((vdev),(type),(v),sizeof(*(v))); \
									\
	BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2		\
		     && sizeof(*(v)) != 4 && sizeof(*(v)) != 8);	\
	if (!_err) {							\
		switch (sizeof(*(v))) {					\
		case 2: le16_to_cpus((__u16 *) v); break;		\
		case 4: le32_to_cpus((__u32 *) v); break;		\
		case 8: le64_to_cpus((__u64 *) v); break;		\
		}							\
	}								\
	_err;								\
})

int __virtio_config_val(struct virtio_device *dev,
			u8 type, void *val, size_t size);

/**
 * virtio_use_bit - helper to use a feature bit in a bitfield value.
 * @dev: the virtio device
 * @token: the token as returned from vdev->config->find().
 * @len: the length of the field.
 * @bitnum: the bit to test.
 *
 * If handed a NULL token, it returns false, otherwise returns bit status.
 * If it's one, it sets the mirroring acknowledgement bit. */
int virtio_use_bit(struct virtio_device *vdev,
		   void *token, unsigned int len, unsigned int bitnum);
#endif /* __KERNEL__ */
#endif /* _LINUX_VIRTIO_CONFIG_H */
Commit	Line	Data
ec3d41c4 RR	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 */