From 701769d87ea3006103c93fd0ecc26875e02d461f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pali=20Roh=C3=A1r?= Date: Thu, 21 Oct 2021 16:46:08 +0200 Subject: [PATCH] arm: mvebu: Add documentation for save_boot_params() function MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Important detail is availability of kwbimage BIN header arguments passed via r0 and r1 registers by BootROM. Signed-off-by: Pali Rohár Reviewed-by: Stefan Roese --- 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 dde77b7652..501c239e9d 100644 --- a/arch/arm/mach-mvebu/lowlevel_spl.S +++ b/arch/arm/mach-mvebu/lowlevel_spl.S @@ -3,6 +3,15 @@ #include #include +/* + * 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 -- 2.39.5