u-boot/doc/README.cfi
Heiko Schocher 466f0137e8 mpc5200, digsy_mtc: add support for rev5 board version
difference to previous board version:
- M29W128GH flash from Numonyx
- SDRAM ISSI IS45S16800 (Option A2 105°C)
- rev5 uses RTC RV-3029-C2
- update cs0 and cs1 baseaddr and length
  depending on the detected flash size.
- added Werner Pfister <Pfister_Werner@intercontrol.de>
  as maintainer for the digsy board variants
- As the M29W128GH needs a special flash_cmd_reset()
  document that in the new file doc/README.cfi.
- move "#endif /* CONFIG_CMD_IDE */" to the right place
- remove LOWBOOT config option for digsy_mtc and digsy_mtc_rev5
  boards
- change doc/README.cfi as Stefan Roese suggested

Signed-off-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>
cc: Wolfgang Denk <hs@denx.de>
cc: Stefan Roese <sr@denx.de>
cc: Werner Pfister <Pfister_Werner@intercontrol.de>
cc: Detlev Zundel <dzu@denx.de>
2011-01-18 23:34:26 +01:00

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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