[U-Boot] [PATCH 3/9] arm: Move CP15 init out of cpu_init_crit()

Albert ARIBAUD
2011-11-05T08:17:46Z

Hi Simon,

Going back to this version of the patch as indicated, I notice something
weird:

Le 13/10/2011 23:05, Simon Glass a ?crit :
> Some SOCs have do not start up with their 'main' CPU. The first U-Boot
> code may then be executed with a CPU which does not have a CP15, or not a
> useful one.
>
> Here we split the initialization of CP15 into a separate call, which can
> be performed later if required.
>
> Once the main CPU is running, you should call cpu_init_cp15() to perform
> this init as early as possible.
>
> Existing ARMv7 boards which define CONFIG_SKIP_LOWLEVEL_INIT should not
> need to change, this CP15 init is still skipped in that case. The only
> impact for these boards is that the cpu_init_cp15() will be available
> even if it is never used on these boards.
>
> Signed-off-by: Simon Glass<sjg@chromium.org>
> ---
> arch/arm/cpu/armv7/start.S | 24 ++++++++++++++++++------
> arch/arm/include/asm/u-boot-arm.h | 3 +++
> 2 files changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
> index db8e9d2..7fdd422 100644
> --- a/arch/arm/cpu/armv7/start.S
> +++ b/arch/arm/cpu/armv7/start.S
> @@ -168,6 +168,7 @@ next:
> #endif
> /* the mask ROM code should have PLL and others stable */
> #ifndef CONFIG_SKIP_LOWLEVEL_INIT
> + bl cpu_reset_cp15
> bl cpu_init_crit
> #endif
>
> @@ -305,17 +306,16 @@ jump_2_ram:
> _board_init_r_ofs:
> .word board_init_r - _start
>
> -
> -#ifndef CONFIG_SKIP_LOWLEVEL_INIT
> /*************************************************************************
> *
> - * CPU_init_critical registers
> + * cpu_reset_cp15
> *
> - * setup important registers
> - * setup memory timing
> + * Setup CP15 registers (cache, MMU, TLBs). The I-cache is turned on unless
> + * CONFIG_SYS_ICACHE_OFF is defined.
> *
> *************************************************************************/
> -cpu_init_crit:
> +.globl cpu_init_cp15
> +cpu_init_cp15:

Seems like half this patch says 'cpu_reset_cp15' and then the second
half says 'cpu_init_cp15' (I prefer 'cpu_init_cp15').

> /*
> * Invalidate L1 I/D
> */
> @@ -340,7 +340,19 @@ cpu_init_crit:
> orr r0, r0, #0x00001000 @ set bit 12 (I) I-cache
> #endif
> mcr p15, 0, r0, c1, c0, 0
> + mov pc, lr @ back to my caller
>
> +
> +#ifndef CONFIG_SKIP_LOWLEVEL_INIT
> +/*************************************************************************
> + *
> + * CPU_init_critical registers
> + *
> + * setup important registers
> + * setup memory timing
> + *
> + *************************************************************************/
> +cpu_init_crit:
> /*
> * Jump to board specific initialization...
> * The Mask ROM will have already initialized
> diff --git a/arch/arm/include/asm/u-boot-arm.h b/arch/arm/include/asm/u-boot-arm.h
> index d3308f7..4ca75f9 100644
> --- a/arch/arm/include/asm/u-boot-arm.h
> +++ b/arch/arm/include/asm/u-boot-arm.h
> @@ -46,6 +46,9 @@ extern ulong IRQ_STACK_START_IN; /* 8 bytes in IRQ stack */
> int cpu_init(void);
> int cleanup_before_linux(void);
>
> +/* Set up ARMv7 MMU, caches and TLBs */
> +void cpu_init_cp15(void);
> +
> /* cpu/.../arch/cpu.c */
> int arch_cpu_init(void);
> int arch_misc_init(void);

Amicalement,
--
Albert.