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