On Tue, Mar 03, 2015 at 08:23:23PM -0700, Simon Glass wrote: > Hi Tom, > > On 3 March 2015 at 13:14, Tom Rini <tr...@konsulko.com> wrote: > > 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. > > I printed out the stack in board_init_r() and it looks right: 32MB > above the base of SDRAM. > > Also I don't seem to get a crash in SPL. How do I make that happen? If > I define CONFIG_SPL_USBETH_SUPPORT I get an error about the .data > section not fitin in .sram for u-boot-spl.
With v5 at least, am335x_boneblack_config running on a BBB does it. I'll try v6 this morning and see what's going on.. -- Tom
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