doc/README.cfi

   1 The common CFI driver provides this weak default implementation for
   2 flash_cmd_reset():
   3
   4 void __flash_cmd_reset(flash_info_t *info)
   5 {
   6         /*
   7          * We do not yet know what kind of commandset to use, so we issue
   8          * the reset command in both Intel and AMD variants, in the hope
   9          * that AMD flash roms ignore the Intel command.
  10          */
  11         flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
  12         flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
  13 }
  14 void flash_cmd_reset(flash_info_t *info)
  15         __attribute__((weak,alias("__flash_cmd_reset")));
  16
  17
  18 Some flash chips seems to have trouble with this reset sequence. In this case
  19 the board specific code can override this weak default version with a board
  20 specific function. For example the digsy_mtc board equipped with the M29W128GH
  21 from Numonyx needs this version to function properly:
  22
  23 void flash_cmd_reset(flash_info_t *info)
  24 {
  25         flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
  26 }
  27
  28 see also:
  29 http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html
  30
  31
  32 Config Option
  33
  34   CONFIG_SYS_MAX_FLASH_SECT: Number of sectors available on Flash device
  35
  36   CONFIG_SYS_FLASH_CFI_WIDTH: Data-width of the flash device
  37
  38   CONFIG_CMD_FLASH: Enables Flash command library
  39
  40   CONFIG_FLASH_CFI_DRIVER: Enables CFI Flash driver
  41
  42   CONFIG_FLASH_CFI_MTD: Enables MTD frame work for NOR Flash devices