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authorSimon Glass <sjg@chromium.org>2017-07-23 21:19:41 -0600
committerTom Rini <trini@konsulko.com>2017-07-25 21:20:02 -0400
commit85fc970d74d09f33fcdcc649e73c5dc4f5334605 (patch)
tree4ba2865dc229971373e8482d990af28c9eea3838 /README
parente73496d08e2dc60f3e00554c71b92f72cdebf0fd (diff)
Convert CONFIG_ENV_IS_IN_FLASH to Kconfig
This converts the following to Kconfig: CONFIG_ENV_IS_IN_FLASH Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'README')
-rw-r--r--README70
1 files changed, 0 insertions, 70 deletions
diff --git a/README b/README
index f09e0db2fb..dc10e4e494 100644
--- a/README
+++ b/README
@@ -3412,76 +3412,6 @@ following configurations:
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_FLASH:
-
- Define this if the environment is in flash memory.
-
- a) The environment occupies one whole flash sector, which is
- "embedded" in the text segment with the U-Boot code. This
- happens usually with "bottom boot sector" or "top boot
- sector" type flash chips, which have several smaller
- sectors at the start or the end. For instance, such a
- layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
- such a case you would place the environment in one of the
- 4 kB sectors - with U-Boot code before and after it. With
- "top boot sector" type flash chips, you would put the
- environment in one of the last sectors, leaving a gap
- between U-Boot and the environment.
-
- - CONFIG_ENV_OFFSET:
-
- Offset of environment data (variable area) to the
- beginning of flash memory; for instance, with bottom boot
- type flash chips the second sector can be used: the offset
- for this sector is given here.
-
- CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
-
- - CONFIG_ENV_ADDR:
-
- This is just another way to specify the start address of
- the flash sector containing the environment (instead of
- CONFIG_ENV_OFFSET).
-
- - CONFIG_ENV_SECT_SIZE:
-
- Size of the sector containing the environment.
-
-
- b) Sometimes flash chips have few, equal sized, BIG sectors.
- In such a case you don't want to spend a whole sector for
- the environment.
-
- - CONFIG_ENV_SIZE:
-
- If you use this in combination with CONFIG_ENV_IS_IN_FLASH
- and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
- of this flash sector for the environment. This saves
- memory for the RAM copy of the environment.
-
- It may also save flash memory if you decide to use this
- when your environment is "embedded" within U-Boot code,
- since then the remainder of the flash sector could be used
- for U-Boot code. It should be pointed out that this is
- STRONGLY DISCOURAGED from a robustness point of view:
- updating the environment in flash makes it always
- necessary to erase the WHOLE sector. If something goes
- wrong before the contents has been restored from a copy in
- RAM, your target system will be dead.
-
- - CONFIG_ENV_ADDR_REDUND
- CONFIG_ENV_SIZE_REDUND
-
- These settings describe a second storage area 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.
-
-BE CAREFUL! Any changes to the flash layout, and some changes to the
-source code will make it necessary to adapt <board>/u-boot.lds*
-accordingly!
-
-
- CONFIG_ENV_IS_IN_NVRAM:
Define this if you have some non-volatile memory device