README.cfi
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The common CFI driver provides this weak default implementation for
flash_cmd_reset():
void __flash_cmd_reset(flash_info_t *info)
{
/*
* We do not yet know what kind of commandset to use, so we issue
* the reset command in both Intel and AMD variants, in the hope
* that AMD flash roms ignore the Intel command.
*/
flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
}
void flash_cmd_reset(flash_info_t *info)
__attribute__((weak,alias("__flash_cmd_reset")));
Some flash chips seems to have trouble with this reset sequence. In this case
the board specific code can override this weak default version with a board
specific function. For example the digsy_mtc board equipped with the M29W128GH
from Numonyx needs this version to function properly:
void flash_cmd_reset(flash_info_t *info)
{
flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
}
see also:
http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html
Config Option
CONFIG_SYS_MAX_FLASH_SECT: Number of sectors available on Flash device
CONFIG_SYS_FLASH_CFI_WIDTH: Data-width of the flash device
CONFIG_CMD_FLASH: Enables Flash command library
CONFIG_FLASH_CFI_DRIVER: Enables CFI Flash driver
CONFIG_FLASH_CFI_MTD: Enables MTD frame work for NOR Flash devices