README: document CONFIG_ENV_IS_IN_SPI_FLASH

The option can be used to save the environment in spi flash.
Implementation code is already exist in command/env_sf.c. But
the documentation is missing.

This patch add the details for this option to the README file.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
This commit is contained in:
Wu, Josh 2014-07-01 19:30:13 +08:00 committed by Tom Rini
parent be354c1a21
commit bd83b59212

37
README
View File

@ -4069,6 +4069,43 @@ to save the current settings.
environment area within the total memory of your DataFlash placed environment area within the total memory of your DataFlash placed
at the specified address. at the specified address.
- CONFIG_ENV_IS_IN_SPI_FLASH:
Define this if you have a SPI Flash memory device which you
want to use for the environment.
- CONFIG_ENV_OFFSET:
- CONFIG_ENV_SIZE:
These two #defines specify the offset and size of the
environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
aligned to an erase sector boundary.
- CONFIG_ENV_SECT_SIZE:
Define the SPI flash's sector size.
- CONFIG_ENV_OFFSET_REDUND (optional):
This setting describes a second storage area of CONFIG_ENV_SIZE
size used to hold a redundant copy of the environment data, so
that there is a valid backup copy in case there is a power failure
during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
aligned to an erase sector boundary.
- CONFIG_ENV_SPI_BUS (optional):
- CONFIG_ENV_SPI_CS (optional):
Define the SPI bus and chip select. If not defined they will be 0.
- CONFIG_ENV_SPI_MAX_HZ (optional):
Define the SPI max work clock. If not defined then use 1MHz.
- CONFIG_ENV_SPI_MODE (optional):
Define the SPI work mode. If not defined then use SPI_MODE_3.
- CONFIG_ENV_IS_IN_REMOTE: - CONFIG_ENV_IS_IN_REMOTE:
Define this if you have a remote memory space which you Define this if you have a remote memory space which you