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

[Simon Glass]

Hi Albert,

On Sat, Nov 5, 2011 at 1:17 AM, Albert ARIBAUD
<albert.u.boot at aribaud.net> wrote:
> 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 écrit :
>>
>> 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 at 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').

Given this and the activity in the past 3 weeks I have done a new
serial v4 with a rebase and this fixed. The only change I made to the
series was in this one patch to correct the first call to
cpu_init_cp15 and update the comment. But I suggest you pick up this
new series to avoid conflicts.

Regards,
Simon

>
>>        /*
>>         * 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.
>