On Tue, Mar 03, 2015 at 12:04:16PM -0700, Simon Glass wrote: > Hi Tom, > > On 3 March 2015 at 10:49, Tom Rini <tr...@konsulko.com> wrote: > > On Tue, Mar 03, 2015 at 08:03:00AM -0700, Simon Glass wrote: > > > >> At present SPL uses a single stack, either CONFIG_SPL_STACK or > >> CONFIG_SYS_INIT_SP_ADDR. Since some SPL features (such as MMC and > >> environment) require a lot of stack, some boards set CONFIG_SPL_STACK to > >> point into SDRAM. They then set up SDRAM very early, before board_init_f(), > >> so that the larger stack can be used. > >> > >> This is an abuse of lowlevel_init(). That function should only be used for > >> essential start-up code which cannot be delayed. An example of a valid use > >> is > >> when only part of the SPL code is visible/executable, and the SoC must be > >> set > >> up so that board_init_f() can be reached. It should not be used for SDRAM > >> init, console init, etc. > >> > >> Add a CONFIG_SPL_STACK_R option, which allows the stack to be moved to a > >> new > >> address before board_init_r() is called in SPL. > >> > >> The expected SPL flow (for CONFIG_SPL_FRAMEWORK) is documented in the > >> README. > >> > >> Signed-off-by: Simon Glass <s...@chromium.org> > >> For version 1: > >> Acked-by: Albert ARIBAUD <albert.u.b...@aribaud.net> > >> Reviewed-by: Stefan Roese <s...@denx.de> > >> Tested-by: Bo Shen <voice.s...@atmel.com> > >> Acked-by: Bo Shen <voice.s...@atmel.com> > >> Acked-by: Heiko Schocher <h...@denx.de> > >> Tested-by: Heiko Schocher <h...@denx.de> > >> --- > >> > >> Changes in v6: None > >> Changes in v5: > >> - Rebase to master > >> > >> Changes in v4: > >> - Adjust README to mention that lowlevel_init() should have no stack > >> > >> Changes in v3: None > >> Changes in v2: > >> - Move docs to top-level README file and expand them to cover U-Boot proper > >> - Add Kconfig settings > >> > >> Kconfig | 18 ++++++++++++++ > >> README | 69 > >> +++++++++++++++++++++++++++++++++++++++++++++++++++++ > >> arch/arm/lib/crt0.S | 13 +++++++--- > >> common/spl/spl.c | 35 +++++++++++++++++++++++++++ > >> 4 files changed, 132 insertions(+), 3 deletions(-) > > [snip] > >> diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S > >> index 22df3e5..7939ced 100644 > >> --- a/arch/arm/lib/crt0.S > >> +++ b/arch/arm/lib/crt0.S > >> @@ -113,7 +113,14 @@ here: > >> /* Set up final (full) environment */ > >> > >> bl c_runtime_cpu_setup /* we still call old routine here */ > >> - > >> +#endif > >> +#if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_FRAMEWORK) > >> +# ifdef CONFIG_SPL_BUILD > >> + /* Use a DRAM stack for the rest of SPL, if requested */ > >> + bl spl_relocate_stack_gd > >> + cmp r0, #0 > >> + movne sp, r0 > >> +# endif > >> ldr r0, =__bss_start /* this is auto-relocated! */ > >> ldr r1, =__bss_end /* this is auto-relocated! */ > >> > >> @@ -124,9 +131,10 @@ clbss_l:cmp r0, r1 /* while not > >> at end of BSS */ > >> addlo r0, r0, #4 /* move to next */ > >> blo clbss_l > >> > >> +#if ! defined(CONFIG_SPL_BUILD) > >> bl coloured_LED_init > >> bl red_led_on > >> - > >> +#endif > >> /* call board_init_r(gd_t *id, ulong dest_addr) */ > >> mov r0, r9 /* gd_t */ > >> ldr r1, [r9, #GD_RELOCADDR] /* dest_addr */ > >> @@ -134,7 +142,6 @@ clbss_l:cmp r0, r1 /* while not > >> at end of BSS */ > >> ldr pc, =board_init_r /* this is auto-relocated! */ > >> > >> /* we should not return here. */ > >> - > >> #endif > >> > >> ENDPROC(_main) > >> diff --git a/common/spl/spl.c b/common/spl/spl.c > >> index ded0f30..cd75bbc 100644 > >> --- a/common/spl/spl.c > >> +++ b/common/spl/spl.c > >> @@ -281,3 +281,38 @@ void preloader_console_init(void) > >> spl_display_print(); > >> #endif > >> } > >> + > >> +/** > >> + * spl_relocate_stack_gd() - Relocate stack ready for board_init_r() > >> execution > >> + * > >> + * Sometimes board_init_f() runs with a stack in SRAM but we want to use > >> SDRAM > >> + * for the main board_init_r() execution. This is typically because we > >> need > >> + * more stack space for things like the MMC sub-system. > >> + * > >> + * This function calculates the stack position, copies the global_data > >> into > >> + * place and returns the new stack position. The caller is responsible for > >> + * setting up the sp register. > >> + * > >> + * @return new stack location, or 0 to use the same stack > >> + */ > >> +ulong spl_relocate_stack_gd(void) > >> +{ > >> +#ifdef CONFIG_SPL_STACK_R > >> + gd_t *new_gd; > >> + ulong ptr; > >> + > >> + /* Get stack position: use 8-byte alignment for ABI compliance */ > >> + ptr = CONFIG_SPL_STACK_R - sizeof(gd_t); > >> + ptr &= ~7; > >> + new_gd = (gd_t *)ptr; > >> + memcpy(new_gd, (void *)gd, sizeof(gd_t)); > >> + gd = new_gd; > >> + > >> + /* Clear the BSS. */ > >> + memset(__bss_start, 0, __bss_end - __bss_start); > >> + > >> + return ptr; > >> +#else > >> + return 0; > >> +#endif > >> +} > > > > All of this _does_ move gd into where CONFIG_SPL_STACK_R points. It > > does _not_ move the stack itself into where CONFIG_SPL_STACK_R points so > > the big use case (am335x_boneblack for example where > > CONFIG_SPL_ENV_SUPPORT is set) doesn't work and blows up as we overflow > > the area for stack. > > OK I'll have to test more. What sort of problem should i see?
We hang on entering env_reloc_spec() which is what puts some big sized variables on the stack. > The return value from spl_relocate_stack_gd() should be shoved into > sp. Does that not happen? It doesn't appear to be. I hadn't broken out the BBB with JTAG tho. -- Tom
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