Builds up envcrc with the target environment so that external utils
may easily extract it and embed it in final U-Boot images.
-- CONFIG_ENV_IS_IN_NVRAM:
-
- Define this if you have some non-volatile memory device
- (NVRAM, battery buffered SRAM) which you want to use for the
- environment.
-
- - CONFIG_ENV_ADDR:
- - CONFIG_ENV_SIZE:
-
- These two #defines are used to determine the memory area you
- want to use for environment. It is assumed that this memory
- can just be read and written to, without any special
- provision.
-
BE CAREFUL! The first access to the environment happens quite early
in U-Boot initialization (when we try to get the setting of for the
console baudrate). You *MUST* have mapped your NVRAM area then, or
keep settings there always unmodified except somebody uses "saveenv"
to save the current settings.
-
-- CONFIG_ENV_IS_IN_EEPROM:
-
- Use this if you have an EEPROM or similar serial access
- device and a driver for it.
-
- - CONFIG_ENV_OFFSET:
- - CONFIG_ENV_SIZE:
-
- These two #defines specify the offset and size of the
- environment area within the total memory of your EEPROM.
-
- - CONFIG_SYS_I2C_EEPROM_ADDR:
- If defined, specified the chip address of the EEPROM device.
- The default address is zero.
-
- - CONFIG_SYS_I2C_EEPROM_BUS:
- If defined, specified the i2c bus of the EEPROM device.
-
- - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
- If defined, the number of bits used to address bytes in a
- single page in the EEPROM device. A 64 byte page, for example
- would require six bits.
-
- - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
- If defined, the number of milliseconds to delay between
- page writes. The default is zero milliseconds.
-
- - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
- The length in bytes of the EEPROM memory array address. Note
- that this is NOT the chip address length!
-
- - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
- EEPROM chips that implement "address overflow" are ones
- like Catalyst 24WC04/08/16 which has 9/10/11 bits of
- address and the extra bits end up in the "chip address" bit
- slots. This makes a 24WC08 (1Kbyte) chip look like four 256
- byte chips.
-
- Note that we consider the length of the address field to
- still be one byte because the extra address bits are hidden
- in the chip address.
-
- - CONFIG_SYS_EEPROM_SIZE:
- The size in bytes of the EEPROM device.
-
- - CONFIG_ENV_EEPROM_IS_ON_I2C
- define this, if you have I2C and SPI activated, and your
- EEPROM, which holds the environment, is on the I2C bus.
-
- - CONFIG_I2C_ENV_EEPROM_BUS
- if you have an Environment on an EEPROM reached over
- I2C muxes, you can define here, how to reach this
- EEPROM. For example:
-
- #define CONFIG_I2C_ENV_EEPROM_BUS 1
-
- EEPROM which holds the environment, is reached over
- a pca9547 i2c mux with address 0x70, channel 3.
-
-- CONFIG_ENV_IS_IN_DATAFLASH:
-
- Define this if you have a DataFlash memory device which you
- want to use for the environment.
-
- - CONFIG_ENV_OFFSET:
- - CONFIG_ENV_ADDR:
- - CONFIG_ENV_SIZE:
-
- These three #defines specify the offset and size of the
- environment area within the total memory of your DataFlash placed
- 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_REDUND 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:
-
- Define this if you have a remote memory space which you
- want to use for the local device's environment.
-
- - CONFIG_ENV_ADDR:
- - CONFIG_ENV_SIZE:
-
- These two #defines specify the address and size of the
- environment area within the remote memory space. The
- local device can get the environment from remote memory
- space by SRIO or PCIE links.
-
BE CAREFUL! For some special cases, the local device can not use
"saveenv" command. For example, the local device will get the
environment stored in a remote NOR flash by SRIO or PCIE link,
environment. If redundant environment is used, it will be copied to
CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
-- CONFIG_ENV_IS_IN_FAT:
- Define this if you want to use the FAT file system for the environment.
-
- - FAT_ENV_INTERFACE:
-
- Define this to a string that is the name of the block device.
-
- - FAT_ENV_DEVICE_AND_PART:
-
- Define this to a string to specify the partition of the device. It can
- be as following:
-
- "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
- - "D:P": device D partition P. Error occurs if device D has no
- partition table.
- - "D:0": device D.
- - "D" or "D:": device D partition 1 if device D has partition
- table, or the whole device D if has no partition
- table.
- - "D:auto": first partition in device D with bootable flag set.
- If none, first valid partition in device D. If no
- partition table then means device D.
-
- - FAT_ENV_FILE:
-
- It's a string of the FAT file name. This file use to store the
- environment.
-
- - CONFIG_FAT_WRITE:
- This must be enabled. Otherwise it cannot save the environment file.
-
Please note that the environment is read-only until the monitor
has been relocated to RAM and a RAM copy of the environment has been
created; also, when using EEPROM you will have to use getenv_f()