Hi Philipp:
On 2017年09月19日 02:18, Philipp Tomsich wrote:
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.
For v2, we force bootrom.o to alway be emitted as A32 (not T32), so we
can safely call save_boot_params_ret().
This still have a problem, because the setjmp implementation for
ARM32 platform has humb code when CONFIG_SYS_THUMB_BUILD is
enabled, this is a default setting for most ARMv7 boards.
#if CONFIG_IS_ENABLED(SYS_THUMB_BUILD)
".align 2\n"
"adr r0, jmp_target\n"
"add r0, r0, $1\n" // r0 stored the jump target address and with
bit[0] = 1, this will trigger a thumb switch in longjmp with code "bx r0"
#endif
When I force the setjmp code go arm code path, I can back to bootrom
successfully, But I got a data abort exception in later. it seems it
happens when bootrom finished the uboot code
copy, when jump to sdram, I need a further debug.
It also turned out that I had not caught the RK3188 in my earlier
series... and my luck being what it is, the RK3188 needed some extra
handholding to adapt to the new regime: instead of passing the context
address (for returning to the BROM) from the TPL to the SPL, the SPL
now returns to the TPL and the TPL then returns to the BROM.
Changes in v2:
- [added in v2] chain back_to_bootrom calls for SPL, first returning
to the TPL (using the same mechanism) and further calling through
to the BROM from the TPL by invoking back_to_bootrom again
- adapt the RK3188 spl support file (that I had originally missed)
Philipp Tomsich (5):
arm: make save_boot_params_ret prototype visible for AArch64
rockchip: back-to-bootrom: replace assembly-implementation with C-code
rockchip: back-to-bootrom: rk3188: chain from SPL via TPL to the BROM
rockchip: back-to-bootrom: allow passing a cmd to the bootrom
rockchip: back-to-bootrom: do not compile bootrom.o in thumb mode
arch/arm/include/asm/arch-rockchip/bootrom.h | 30 +++++++++---
arch/arm/include/asm/system.h | 62 ++++++++++++-------------
arch/arm/mach-rockchip/Makefile | 10 +++-
arch/arm/mach-rockchip/bootrom.c | 54 +++++++++++++++++++++-
arch/arm/mach-rockchip/rk3036-board-spl.c | 2 +-
arch/arm/mach-rockchip/rk3188-board-spl.c | 14 +-----
arch/arm/mach-rockchip/rk3188-board-tpl.c | 19 ++++----
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 ----------------------------
12 files changed, 133 insertions(+), 137 deletions(-)
delete mode 100644 arch/arm/mach-rockchip/save_boot_param.S
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