u-boot-brain/drivers/mtd/nand/Kconfig
Masahiro Yamada e02ee2548a kconfig: switch to single .config configuration
When Kconfig for U-boot was examined, one of the biggest issues was
how to support multiple images (Normal, SPL, TPL).  There were
actually two options, "single .config" and "multiple .config".
After some discussions and thought experiments, I chose the latter,
i.e. to create ".config", "spl/.config", "tpl/.config" for Normal,
SPL, TPL, respectively.

It is true that the "multiple .config" strategy provided us the
maximum flexibility and helped to avoid duplicating CONFIGs among
Normal, SPL, TPL, but I have noticed some fatal problems:

[1] It is impossible to share CONFIG options across the images.
  If you change the configuration of Main image, you often have to
  adjust some SPL configurations correspondingly.  Currently, we
  cannot handle the dependencies between them.  It means one of the
  biggest advantages of Kconfig is lost.

[2] It is too painful to change both ".config" and "spl/.config".
  Sunxi guys started to work around this problem by creating a new
  configuration target.  Commit cbdd9a9737 (sunxi: kconfig: Add
  %_felconfig rule to enable FEL build of sunxi platforms.) added
  "make *_felconfig" to enable CONFIG_SPL_FEL on both images.
  Changing the configuration of multiple images in one command is a
  generic demand.  The current implementation cannot propose any
  good solution about this.

[3] Kconfig files are getting ugly and difficult to understand.
  Commit b724bd7d63 (dm: Kconfig: Move CONFIG_SYS_MALLOC_F_LEN to
  Kconfig) has sprinkled "if !SPL_BUILD" over the Kconfig files.

[4] The build system got more complicated than it should be.
  To adjust Linux-originated Kconfig to U-Boot, the helper script
  "scripts/multiconfig.sh" was introduced.  Writing a complicated
  text processor is a shell script sometimes caused problems.

Now I believe the "single .config" will serve us better.  With it,
all the problems above would go away.  Instead, we will have to add
some CONFIG_SPL_* (and CONFIG_TPL_*) options such as CONFIG_SPL_DM,
but we will not have much.  Anyway, this is what we do now in
scripts/Makefile.spl.

I admit my mistake with my apology and this commit switches to the
single .config configuration.

It is not so difficult to do that:

 - Remove unnecessary processings from scripts/multiconfig.sh
  This file will remain for a while to support the current defconfig
  format.  It will be removed after more cleanups are done.

 - Adjust some makefiles and Kconfigs

 - Add some entries to include/config_uncmd_spl.h and the new file
   scripts/Makefile.uncmd_spl.  Some CONFIG options that are not
   supported on SPL must be disabled because one .config is shared
   between SPL and U-Boot proper going forward.  I know this is not
   a beautiful solution and I think we can do better, but let's see
   how much we will have to describe them.

 - update doc/README.kconfig

More cleaning up patches will follow this.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2015-02-24 17:06:23 -05:00

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menu "NAND Device Support"
config SYS_NAND_SELF_INIT
bool
help
This option, if enabled, provides more flexible and linux-like
NAND initialization process.
if !SPL_BUILD
config NAND_DENALI
bool "Support Denali NAND controller"
select SYS_NAND_SELF_INIT
help
Enable support for the Denali NAND controller.
config SYS_NAND_DENALI_64BIT
bool "Use 64-bit variant of Denali NAND controller"
depends on NAND_DENALI
help
The Denali NAND controller IP has some variations in terms of
the bus interface. The DMA setup sequence is completely differenct
between 32bit / 64bit AXI bus variants.
If your Denali NAND controller is the 64-bit variant, say Y.
Otherwise (32 bit), say N.
config NAND_DENALI_SPARE_AREA_SKIP_BYTES
int "Number of bytes skipped in OOB area"
depends on NAND_DENALI
range 0 63
help
This option specifies the number of bytes to skip from the beginning
of OOB area before last ECC sector data starts. This is potentially
used to preserve the bad block marker in the OOB area.
endif
if SPL
config SPL_NAND_DENALI
bool "Support Denali NAND controller for SPL"
help
This is a small implementation of the Denali NAND controller
for use on SPL.
endif
endmenu