Important detail is availability of kwbimage BIN header arguments passed
via r0 and r1 registers by BootROM.
Signed-off-by: Pali Rohár <p...@kernel.org>
---
arch/arm/mach-mvebu/lowlevel_spl.S | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/arm/mach-mvebu/lowlevel_spl.S
b/arch/arm/mach-mvebu/lowlevel_spl.S
index dde77b765214..39d42912c49f 100644
--- a/arch/arm/mach-mvebu/lowlevel_spl.S
+++ b/arch/arm/mach-mvebu/lowlevel_spl.S
@@ -3,6 +3,15 @@
#include <config.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)
stmfd sp!, {r0 - r12, lr} /* @ save registers on stack */
ldr r12, =CONFIG_SPL_BOOTROM_SAVE
--
2.20.1
