diff options
| author | Andreas Dannenberg <dannenberg@ti.com> | 2019-06-04 17:55:45 -0500 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2019-07-17 11:12:54 -0400 |
| commit | a5a5d997b41a1b63eed67e78fac1d015e3e070e2 (patch) | |
| tree | 1294b16a216d02aeeb470ff791a7015be86d2478 /arch/arm | |
| parent | 70942db4dd1c5f177ea750df301d5b80c1fc15dc (diff) | |
spl: Allow performing BSS init early before board_init_f()
On some platform we have sufficient memory available early on to allow
setting up and using a basic BSS prior to entering board_init_f(). Doing
so can for example be used to carry state over to board_init_r() without
having to resort to extending U-Boot's global data structure.
To support such scenarios add a Kconfig option called CONFIG_SPL_EARLY_BSS
to allow moving the initialization of BSS prior to entering board_init_f(),
if enabled. Note that using this option usually should go along with using
CONFIG_SPL_SEPARATE_BSS and configuring BSS to be located in memory
actually available prior to board_init_f().
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/lib/crt0.S | 53 |
1 files changed, 36 insertions, 17 deletions
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S index 30fba20e1b..c74641dcd9 100644 --- a/arch/arm/lib/crt0.S +++ b/arch/arm/lib/crt0.S @@ -58,6 +58,33 @@ */ /* + * Macro for clearing BSS during SPL execution. Usually called during the + * relocation process for most boards before entering board_init_r(), but + * can also be done early before entering board_init_f() on plaforms that + * can afford it due to sufficient memory being available early. + */ + +.macro SPL_CLEAR_BSS + ldr r0, =__bss_start /* this is auto-relocated! */ + +#ifdef CONFIG_USE_ARCH_MEMSET + ldr r3, =__bss_end /* this is auto-relocated! */ + mov r1, #0x00000000 /* prepare zero to clear BSS */ + + subs r2, r3, r0 /* r2 = memset len */ + bl memset +#else + ldr r1, =__bss_end /* this is auto-relocated! */ + mov r2, #0x00000000 /* prepare zero to clear BSS */ + +clbss_l:cmp r0, r1 /* while not at end of BSS */ + strlo r2, [r0] /* clear 32-bit BSS word */ + addlo r0, r0, #4 /* move to next */ + blo clbss_l +#endif +.endm + +/* * entry point of crt0 sequence */ @@ -82,6 +109,10 @@ ENTRY(_main) mov r9, r0 bl board_init_f_init_reserve +#if defined(CONFIG_SPL_EARLY_BSS) + SPL_CLEAR_BSS +#endif + mov r0, #0 bl board_init_f @@ -119,6 +150,11 @@ here: bl c_runtime_cpu_setup /* we still call old routine here */ #endif #if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_FRAMEWORK) + +#if !defined(CONFIG_SPL_EARLY_BSS) + SPL_CLEAR_BSS +#endif + # ifdef CONFIG_SPL_BUILD /* Use a DRAM stack for the rest of SPL, if requested */ bl spl_relocate_stack_gd @@ -126,23 +162,6 @@ here: movne sp, r0 movne r9, r0 # endif - ldr r0, =__bss_start /* this is auto-relocated! */ - -#ifdef CONFIG_USE_ARCH_MEMSET - ldr r3, =__bss_end /* this is auto-relocated! */ - mov r1, #0x00000000 /* prepare zero to clear BSS */ - - subs r2, r3, r0 /* r2 = memset len */ - bl memset -#else - ldr r1, =__bss_end /* this is auto-relocated! */ - mov r2, #0x00000000 /* prepare zero to clear BSS */ - -clbss_l:cmp r0, r1 /* while not at end of BSS */ - strlo r2, [r0] /* clear 32-bit BSS word */ - addlo r0, r0, #4 /* move to next */ - blo clbss_l -#endif #if ! defined(CONFIG_SPL_BUILD) bl coloured_LED_init |