arm: mvebu: Add documentation for save_boot_params() function

Important detail is availability of kwbimage BIN header arguments passed
via r0 and r1 registers by BootROM.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Pali Rohár
2021-10-21 16:46:08 +02:00
committed by Stefan Roese
parent e58f08b479
commit 701769d87e

View File

@@ -3,6 +3,15 @@
#include <config.h> #include <config.h>
#include <linux/linkage.h> #include <linux/linkage.h>
/*
* BootROM loads the header part of kwbimage into L2 cache. BIN header usually
* contains U-Boot SPL, optionally it can also contain additional arguments.
* The number of these arguments is in r0, pointer to the argument array in r1.
* BootROM expects executable BIN header code to return to address stored in lr.
* Other registers (r2 - r12) must be preserved. We save all registers to
* CONFIG_SPL_BOOTROM_SAVE address. BIN header arguments (passed via r0 and r1)
* are currently not used by U-Boot SPL binary.
*/
ENTRY(save_boot_params) ENTRY(save_boot_params)
stmfd sp!, {r0 - r12, lr} /* @ save registers on stack */ stmfd sp!, {r0 - r12, lr} /* @ save registers on stack */
ldr r12, =CONFIG_SPL_BOOTROM_SAVE ldr r12, =CONFIG_SPL_BOOTROM_SAVE