Hi, On 18 January 2015 at 23:46, Heiko Schocher <h...@denx.de> wrote: > Hello Simon, > > added Bo Shen to cc, as he currently try to set BSS (and stack) into > SDRAM for at91 based boards ... Bo, could you try this aproach? > > Am 18.01.2015 19:55, schrieb Simon Glass: > >> 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 now: >> >> Execution starts with start.S. Two main functions can be provided by the >> board implementation. The purpose and limitations of each is described >> below. >> After that, the common board_init_r() is called to perform the SPL task. >> >> lowlevel_init(): >> - purpose: essential init to permit execution to reach >> board_init_f() >> - no global_data, but there is a stack >> - must not set up SDRAM or use console >> - must only do the bare minimum to allow execution to continue to >> board_init_f() >> - this is almost never needed >> - return normally from this function >> >> board_init_f(): >> - purpose: set up the machine ready for running board_init_r(): >> i.e. SDRAM and serial UART >> - global_data is available >> - preloader_console_init() can be called here in extremis >> - stack is in SRAM >> - should set up SDRAM, and anything needed to make the UART work >> - these is no need to clear BSS, it will be done by crt0.S >> - must return normally from this function (don't call >> board_init_r() >> directly) >> >> Here the BSS is cleared. If CONFIG_SPL_STACK_R is defined, then at this >> point >> the stack and global_data are relocated to below that address. >> >> board_init_r(): >> - purpose: main execution, common code >> - global_data is available >> - SDRAM is available >> - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined >> and >> points into SDRAM >> - preloader_console_init() can be called here - typically this is >> done by defining CONFIG_SPL_BOARD_INIT and then supplying >> a >> spl_board_init() function containing this call >> - loads U-Boot or (in falcon mode) Linux >> >> Note: This patch is intended to apply over the top of Tom's SPL changes >> and > > > Sound good! Can you point me, which patches you mean? Thanks! >
Tom's ones are here, although he is planning to update them I think. http://patchwork.ozlabs.org/patch/422992/ http://patchwork.ozlabs.org/patch/422993/ >> this series: >> >> https://patchwork.ozlabs.org/patch/423785/ >> >> Signed-off-by: Simon Glass <s...@chromium.org> >> --- >> >> arch/arm/lib/crt0.S | 13 ++++++++++--- >> common/spl/spl.c | 35 +++++++++++++++++++++++++++++++++++ >> doc/README.SPL | 42 ++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 87 insertions(+), 3 deletions(-) > > > Hmm... I miss here "arch/arm/lib/spl.c" where "clearing BSS" > should get removed ... or? > I haven't removed it from existing board code, just added it to crt0.S so that it will then be possible to clean up the board code. > >> 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 1826c47..78bb279 100644 >> --- a/common/spl/spl.c >> +++ b/common/spl/spl.c >> @@ -276,3 +276,38 @@ 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 >> +} > > > I try this patch out on a sam9260 board with 4k sram for SPL (if I have the > hw) ... looking into my current objdump with the approach from Bo, > see patch [1], I do not find "memcpy" in it ... I currently have a > SPL size (untested, compiled code only) currently from 3392 bytes, which > perfectly fits in 4k ... adding a memcpy in code, I get a size of 3464 bytes > fits also in 4k ... with space for some init stack in sram ... so, I try > your patch ASAP, thanks! OK thanks. - Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot