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threewire.h
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threewire.h
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#ifndef _GPXE_THREEWIRE_H
#define _GPXE_THREEWIRE_H
/** @file
*
* Three-wire serial interface
*
* The Atmel three-wire interface is a subset of the (newer) SPI
* interface, and is implemented here as a layer on top of the SPI
* support.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <gpxe/spi.h>
#include <limits.h>
/**
* @defgroup tcmds Three-wire commands
* @{
*/
/** Read data from memory array */
#define THREEWIRE_READ 0x6
/** Write data to memory array */
#define THREEWIRE_WRITE 0x5
/** Write enable */
#define THREEWIRE_EWEN 0x4
/** Address to be used for write enable command */
#define THREEWIRE_EWEN_ADDRESS INT_MAX
/** Time to wait for write cycles to complete
*
* This is sufficient for AT93C46/AT93C56 devices, but may need to be
* increased in future when other devices are added.
*/
#define THREEWIRE_WRITE_MDELAY 10
/** @} */
extern int threewire_read ( struct nvs_device *nvs, unsigned int address,
void *data, size_t len );
extern int threewire_write ( struct nvs_device *nvs, unsigned int address,
const void *data, size_t len );
extern int threewire_detect_address_len ( struct spi_device *device );
/**
* @defgroup tdevs Three-wire device types
* @{
*/
static inline __attribute__ (( always_inline )) void
init_at93cx6 ( struct spi_device *device, unsigned int organisation ) {
device->nvs.word_len_log2 = ( ( organisation == 8 ) ? 0 : 1 );
device->nvs.block_size = 1;
device->command_len = 3,
device->nvs.read = threewire_read;
device->nvs.write = threewire_write;
}
/**
* Initialise Atmel AT93C46 serial EEPROM
*
* @v device SPI device
* @v organisation Word organisation (8 or 16)
*/
static inline __attribute__ (( always_inline )) void
init_at93c46 ( struct spi_device *device, unsigned int organisation ) {
device->nvs.size = ( 1024 / organisation );
device->address_len = ( ( organisation == 8 ) ? 7 : 6 );
init_at93cx6 ( device, organisation );
}
/**
* Initialise Atmel AT93C56 serial EEPROM
*
* @v device SPI device
* @v organisation Word organisation (8 or 16)
*/
static inline __attribute__ (( always_inline )) void
init_at93c56 ( struct spi_device *device, unsigned int organisation ) {
device->nvs.size = ( 2048 / organisation );
device->address_len = ( ( organisation == 8 ) ? 9 : 8 );
init_at93cx6 ( device, organisation );
}
/**
* Initialise Atmel AT93C66 serial EEPROM
*
* @v device SPI device
* @v organisation Word organisation (8 or 16)
*/
static inline __attribute__ (( always_inline )) void
init_at93c66 ( struct spi_device *device, unsigned int organisation ) {
device->nvs.size = ( 4096 / organisation );
device->address_len = ( ( organisation == 8 ) ? 9 : 8 );
init_at93cx6 ( device, organisation );
}
/** @} */
#endif /* _GPXE_THREEWIRE_H */