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#ifndef _GPXE_NVS_H
#define _GPXE_NVS_H
/** @file
*
* Non-volatile storage
*
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdint.h>
/** A non-volatile storage device */
struct nvs_device {
/** Word length
*
* This is expressed as the base-2 logarithm of the word
* length in bytes. A value of 0 therefore translates as
* 8-bit words, and a value of 1 translates as 16-bit words.
*/
unsigned int word_len_log2;
/** Device size (in words) */
unsigned int size;
/** Data block size (in words)
*
* This is the block size used by the device. It must be a
* power of two. Data reads and writes must not cross a block
* boundary.
*
* Many devices allow reads to cross a block boundary, and
* restrict only writes. For the sake of simplicity, we
* assume that the same restriction applies to both reads and
* writes.
*/
unsigned int block_size;
/** Read data from device
*
* @v nvs NVS device
* @v address Address from which to read
* @v data Data buffer
* @v len Length of data buffer
* @ret rc Return status code
*
* Reads may not cross a block boundary.
*/
int ( * read ) ( struct nvs_device *nvs, unsigned int address,
void *data, size_t len );
/** Write data to device
*
* @v nvs NVS device
* @v address Address to which to write
* @v data Data buffer
* @v len Length of data buffer
* @ret rc Return status code
*
* Writes may not cross a block boundary.
*/
int ( * write ) ( struct nvs_device *nvs, unsigned int address,
const void *data, size_t len );
};
extern int nvs_read ( struct nvs_device *nvs, unsigned int address,
void *data, size_t len );
extern int nvs_write ( struct nvs_device *nvs, unsigned int address,
const void *data, size_t len );
#endif /* _GPXE_NVS_H */
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