Recent discussions confirmed (what the code always assumed): the Rockchip BROM always enters U-Boot with the stack-pointer valid (i.e. the U-Boot startup code is running off the BROM stack).
We can thus replace the back-to-bootrom code (i.e. both the save_boot_params and back_to_bootrom implementations) using C-code based on setjmp/longjmp. The new implementation is already structured to allow an easy drop-in of Andy's changes to enter download-mode when returning to the BROM.
This entails one minor tweak to asm/system.h, which only exported the save_boot_params_ret prototype for ARMv7, but not for AArch64.
Philipp Tomsich (3): arm: make save_boot_params_ret prototype visible for AArch64 rockchip: back-to-bootrom: replace assembly-implementation with C-code rockchip: back-to-bootrom: allow passing a cmd to the bootrom
arch/arm/include/asm/arch-rockchip/bootrom.h | 30 +++++++++--- arch/arm/include/asm/system.h | 62 ++++++++++++------------- arch/arm/mach-rockchip/Makefile | 4 +- arch/arm/mach-rockchip/bootrom.c | 54 +++++++++++++++++++++- arch/arm/mach-rockchip/rk3036-board-spl.c | 2 +- arch/arm/mach-rockchip/rk3188-board-tpl.c | 2 +- arch/arm/mach-rockchip/rk322x-board-spl.c | 2 +- arch/arm/mach-rockchip/rk3288-board-spl.c | 4 +- arch/arm/mach-rockchip/rk3368-board-tpl.c | 2 +- arch/arm/mach-rockchip/rk3399-board-spl.c | 2 +- arch/arm/mach-rockchip/save_boot_param.S | 69 ---------------------------- 11 files changed, 115 insertions(+), 118 deletions(-) delete mode 100644 arch/arm/mach-rockchip/save_boot_param.S