Hello Simon,
On Tue, 3 Feb 2015 21:18:51 -0700, Simon Glass <s...@chromium.org>
wrote:
> Some boards want to skip the normal reset init. For example OMAP4 SPL
> does not want to touch VBAR and many boards don't want to set up
> CP15.
>
> Provide a return value from save_boot_params() which allows the board
> to indicate what reset processing should be done.
Does this have to be at run-time? I'd rather it were a build-time
config option.
> Signed-off-by: Simon Glass <s...@chromium.org>
> ---
>
> arch/arm/cpu/armv7/exynos/spl_boot.c | 5 ++++-
> arch/arm/cpu/armv7/start.S | 11 ++++++++---
> arch/arm/include/asm/system.h | 15 +++++++++++++++
> 3 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/cpu/armv7/exynos/spl_boot.c
> b/arch/arm/cpu/armv7/exynos/spl_boot.c
> index bc237c9..6e249f1 100644
> --- a/arch/arm/cpu/armv7/exynos/spl_boot.c
> +++ b/arch/arm/cpu/armv7/exynos/spl_boot.c
> @@ -309,4 +309,7 @@ void board_init_r(gd_t *id, ulong dest_addr)
> while (1)
> ;
> }
> -void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3) {}
> +u32 save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3)
> +{
> + return 0;
> +}
> diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
> index c5f94ef..0ba26f7 100644
> --- a/arch/arm/cpu/armv7/start.S
> +++ b/arch/arm/cpu/armv7/start.S
> @@ -52,6 +52,9 @@ reset:
> * Continue to use ROM code vector only in OMAP4 spl)
> */
> #if !(defined(CONFIG_OMAP44XX) && defined(CONFIG_SPL_BUILD))
> + teq r0, #RESET_SKIP_VBVAR
> + bne vbar_done
> +
> /* Set V=0 in CP15 SCTLR register - for VBAR to point to vector */
> mrc p15, 0, r2, c1, c0, 0 @ Read CP15 SCTLR Register
> bic r2, #CR_V @ V = 0
> @@ -61,10 +64,11 @@ reset:
> ldr r2, =_start
> mcr p15, 0, r2, c12, c0, 0 @Set VBAR
> #endif
> -
> +vbar_done:
> /* the mask ROM code should have PLL and others stable */
> #ifndef CONFIG_SKIP_LOWLEVEL_INIT
> - bl cpu_init_cp15
> + teq r0, #RESET_SKIP_CP15
> + bleq cpu_init_cp15
> bl cpu_init_crit
> #endif
>
> @@ -88,11 +92,12 @@ ENDPROC(c_runtime_cpu_setup)
>
> /*************************************************************************
> *
> - * void save_boot_params(u32 r2, u32 r1, u32 r2, u32 r3)
> + * u32 save_boot_params(u32 r2, u32 r1, u32 r2, u32 r3)
> * __attribute__((weak));
> *
> * Stack pointer is not yet initialized at this moment
> * Don't save anything to stack even if compiled with -O0
> + * Return flags - see RESET_... in system.h
> *
> *************************************************************************/
> ENTRY(save_boot_params)
> diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
> index 89f2294..98e49a7 100644
> --- a/arch/arm/include/asm/system.h
> +++ b/arch/arm/include/asm/system.h
> @@ -140,8 +140,23 @@ void flush_l3_cache(void);
> */
> #define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t"
>
> +/* Control bits for reset processing */
> +#define RESET_SKIP_VBVAR (1 << 0) /* Skip vector address setup */
> +#define RESET_SKIP_CP15 (1 << 1) /* Skip CP15 setup */
> +
> #ifndef __ASSEMBLY__
>
> +/**
> + * save_boot_params() - Save boot parameters before starting reset sequence
> + *
> + * @r0: Value of r0
> + * @r1: Value of r1
> + * @r2: Value of r2
> + * @r3: Value of r3
> + * @return reset flags (see RESET_... above)
> + */
> +u32 save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3);
> +
> #define isb() __asm__ __volatile__ ("" : : : "memory")
>
> #define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
> --
> 2.2.0.rc0.207.ga3a616c
>
Amicalement,
--
Albert.
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