arm: spl: Allow board_init_r() to run with a larger stack

At present SPL uses a single stack, either CONFIG_SPL_STACK or
CONFIG_SYS_INIT_SP_ADDR. Since some SPL features (such as MMC and
environment) require a lot of stack, some boards set CONFIG_SPL_STACK to
point into SDRAM. They then set up SDRAM very early, before board_init_f(),
so that the larger stack can be used.

This is an abuse of lowlevel_init(). That function should only be used for
essential start-up code which cannot be delayed. An example of a valid use is
when only part of the SPL code is visible/executable, and the SoC must be set
up so that board_init_f() can be reached. It should not be used for SDRAM
init, console init, etc.

Add a CONFIG_SPL_STACK_R option, which allows the stack to be moved to a new
address before board_init_r() is called in SPL.

The expected SPL flow (for CONFIG_SPL_FRAMEWORK) is documented in the README.

Signed-off-by: Simon Glass <sjg@chromium.org>
For version 1:
Acked-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Heiko Schocher <hs@denx.de>
Tested-by: Heiko Schocher <hs@denx.de>

Signed-off-by: Tom Rini <trini@konsulko.com>
This commit is contained in:
Simon Glass
2015-03-03 08:03:00 -07:00
committed by Tom Rini
parent bdfb34167f
commit db910353a1
4 changed files with 132 additions and 3 deletions

18
Kconfig
View File

@ -96,6 +96,24 @@ config SPL
help
If you want to build SPL as well as the normal image, say Y.
config SPL_STACK_R
depends on SPL
bool "Enable SDRAM location for SPL stack"
help
SPL starts off execution in SRAM and thus typically has only a small
stack available. Since SPL sets up DRAM while in its board_init_f()
function, it is possible for the stack to move there before
board_init_r() is reached. This option enables a special SDRAM
location for the SPL stack. U-Boot SPL switches to this after
board_init_f() completes, and before board_init_r() starts.
config SPL_STACK_R_ADDR
depends on SPL_STACK_R
hex "SDRAM location for SPL stack"
help
Specify the address in SDRAM for the SPL stack. This will be set up
before board_init_r() is called.
config TPL
bool
depends on SPL && SUPPORT_TPL