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 turned out to require a some tweaking to system.h (making sure that the prototype for save_boot_params_ret is visible for A64)and start.S (so binutils knows that this is a possible function entry and it can correctly insert A32-to-Thumb transitions) and taking the axe to setjmp.h (which created quite a few issues with it not expecting A32/T32/Thumb call-sites and some fragility from GCC being smart about the clobber-list of the inline assembly... which led to r9 not being saved or restored).
For v4+: To fix issues with the RK3188 support, this also updates the boot0 hook changes (i.e. allowing the boot0-hook to insert code/data before the ARM vector table) that Kever had submitted this spring and implements a similar "early back-to-bootrom" as suggested by Pawel (for the RK3066) as a generic mechanism.
Changes in v4: - after merging the 'back-to-bootrom' series with the 'boot0-hook' series, this drops the TPL stub and builds only a single SPL image that uses the 'early back-to-bootrom' logic originally implemented by Pawel for the RK3066. - changes the SPL_STACK_BASE to +0x800 (from +0x804), as the boot0 hook already reserves the space for the SPL magic (previously inserted by mkimage) - no longer updates rk3188-board-tpl.c (as we have just removed it in an earlier commit of the series)
Changes in v3: - tracked the root-cause why no interwork branch was emitted and fixed it using a '.type'-directive in start.S to mark save_boot_params_ret as a (possible) function-entry. - converted setjmp/longjmp from inline-assembly to separate .S files to improve predicatability if emitted code
Changes in v2: - [added in v2] chain back_to_bootrom calls for SPL, first returning to the TPL (using the same mechanism) and the to the BROM from the TPL - also covers the RK3188 (which I had originally missed)
Kever Yang (3): rockchip: boot0: align to 0x20 for armv7 '_start' rockchip: mkimage: use spl_boot0 for all Rockchip SoCs rockchip: rk3288: use aligned address for SPL_TEXT_BASE
Philipp Tomsich (15): arm: boot0 hook: move boot0 hook before '_start' rockchip: enable boot0-hook for all Rockchip SoCs rockchip: rk3036: use aligned address for SPL_TEXT_BASE socfpga: boot0 hook: adjust to unified boot0 semantics bcm235xx: boot0 hook: adjust to unified boot0 semantics bcm281xx: boot0 hook: adjust to unified boot0 semantics rockchip: boot0 hook: support early return for RK3188/RK3066-style BROM arm: make save_boot_params_ret prototype visible for AArch64 arm: mark save_boot_params_ret as a function arm: provide a PCS-compliant setjmp implementation rockchip: back-to-bootrom: replace assembly-implementation with C-code rockchip: rk3188: use boot0 hook to load up SPL in 2 steps rockchip: back-to-bootrom: allow passing a cmd to the bootrom rockchip: rk3188: move CONFIG_SPL_* entries from rk3188_common.h to Kconfig rockchip: mkimage: remove unused code-paths (spl_boot0 is now implied)
arch/arm/Kconfig | 1 + arch/arm/cpu/armv7/start.S | 1 + arch/arm/include/asm/arch-bcm235xx/boot0.h | 2 + arch/arm/include/asm/arch-bcm281xx/boot0.h | 2 + arch/arm/include/asm/arch-rockchip/boot0.h | 37 ++++++++--- arch/arm/include/asm/arch-rockchip/bootrom.h | 30 ++++++--- arch/arm/include/asm/setjmp.h | 94 ++++------------------------ arch/arm/include/asm/system.h | 62 +++++++++--------- arch/arm/lib/Makefile | 6 ++ arch/arm/lib/setjmp.S | 37 +++++++++++ arch/arm/lib/setjmp_aarch64.S | 42 +++++++++++++ arch/arm/lib/vectors.S | 54 ++++++++++------ arch/arm/mach-rockchip/Kconfig | 39 ++++++++++-- arch/arm/mach-rockchip/Makefile | 5 +- 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 | 86 ------------------------- arch/arm/mach-rockchip/rk322x-board-spl.c | 2 +- arch/arm/mach-rockchip/rk3288-board-spl.c | 4 +- arch/arm/mach-rockchip/rk3288-board-tpl.c | 2 +- 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 -------------------- arch/arm/mach-socfpga/include/mach/boot0.h | 3 + doc/README.rockchip | 10 +-- include/configs/rk3036_common.h | 2 +- include/configs/rk3188_common.h | 18 +----- include/configs/rk3288_common.h | 2 +- tools/rkcommon.c | 45 +++++-------- 30 files changed, 347 insertions(+), 382 deletions(-) create mode 100644 arch/arm/lib/setjmp.S create mode 100644 arch/arm/lib/setjmp_aarch64.S delete mode 100644 arch/arm/mach-rockchip/rk3188-board-tpl.c delete mode 100644 arch/arm/mach-rockchip/save_boot_param.S