Am Dienstag, 19. September 2017, 11:10:29 CEST schrieb Dr. Philipp Tomsich: > Andy, > > > On 19 Sep 2017, at 09:19, Andy Yan <andy....@rock-chips.com> wrote: > > > > Hi Philipp: > > > > On 2017年09月19日 10:06, Andy Yan wrote: > >> 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. > > > > I found that r9 also need to be preserved, it seems that it hold the sdram > > base. > Thanks for testing and debugging: this is invaluable support, as I only have > AArch64 boards to test. > > The r9 issue will be easy enough to resolve. > However, it looks like I will need more work on setjmp/longjmp to make this > safe both for T32 and A32. Plus: I need to figure out why this didn’t show > in my disassembly (I don’t remember whether it was a rk3188 or rk3288 board > I looked at). > > Might be tomorrow or Thursday until I can provide an new version.
From this conversation, it looks to me that I should wait for that new version for testing on rk3188, as it will likely show the same issues, right? Heiko _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
