[U-Boot] [PATCH v3 1/4] arm: do not force d-cache enable on all boards

[V, Aneesh]

Hi Simon,

On Sun, Aug 14, 2011 at 4:39 PM, Simon Guinot <simon at sequanux.org> wrote:
> Hi Aneesh,
>
> On Thu, Aug 11, 2011 at 08:05:42PM +0530, Aneesh V wrote:
>> c2dd0d45540397704de9b13287417d21049d34c6 added dcache_enable()
>> to board_init_r(). This enables d-cache for all ARM boards.
>> As a result some of the arm boards that are not cache-ready
>> are broken. Revert this change and allow platform code to
>> take the decision on d-cache enabling.
>>
>> Also add some documentation for cache usage in ARM.
>>
>> Signed-off-by: Aneesh V <aneesh at ti.com>
>> ---
>> V2:
>>  Updated with additional guidelines in the README.
>> ---
>>  arch/arm/lib/board.c  |    8 ++----
>>  arch/arm/lib/cache.c  |   12 +++++++++++
>>  doc/README.arm-caches |   51 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  include/common.h      |    1 +
>>  4 files changed, 67 insertions(+), 5 deletions(-)
>>  create mode 100644 doc/README.arm-caches
>>
>> diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
>> index 14a56f6..38a31d8 100644
>> --- a/arch/arm/lib/board.c
>> +++ b/arch/arm/lib/board.c
>> @@ -451,11 +451,9 @@ void board_init_r(gd_t *id, ulong dest_addr)
>>       gd->flags |= GD_FLG_RELOC;      /* tell others: relocation done */
>>
>>       monitor_flash_len = _end_ofs;
>> -     /*
>> -      * Enable D$:
>> -      * I$, if needed, must be already enabled in start.S
>> -      */
>> -     dcache_enable();
>> +
>> +     /* Enable caches */
>> +     enable_caches();
>>
>>       debug("monitor flash len: %08lX\n", monitor_flash_len);
>>       board_init();   /* Setup chipselects */
>> diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
>> index 92b61a2..b545fb7 100644
>> --- a/arch/arm/lib/cache.c
>> +++ b/arch/arm/lib/cache.c
>> @@ -53,3 +53,15 @@ void       __flush_dcache_all(void)
>>  }
>>  void flush_dcache_all(void)
>>       __attribute__((weak, alias("__flush_dcache_all")));
>> +
>> +
>> +/*
>> + * Default implementation of enable_caches()
>> + * Real implementation should be in platform code
>> + */
>> +void __enable_caches(void)
>> +{
>> +     puts("WARNING: Caches not enabled\n");
>> +}
>> +void enable_caches(void)
>> +     __attribute__((weak, alias("__enable_caches")));
>> diff --git a/doc/README.arm-caches b/doc/README.arm-caches
>> new file mode 100644
>> index 0000000..a833eee
>> --- /dev/null
>> +++ b/doc/README.arm-caches
>> @@ -0,0 +1,51 @@
>> +Disabling I-cache:
>> +- Set CONFIG_SYS_ICACHE_OFF
>> +
>> +Disabling D-cache:
>> +- Set CONFIG_SYS_DCACHE_OFF
>> +
>> +Enabling I-cache:
>> +- Make sure CONFIG_SYS_ICACHE_OFF is not set and call icache_enable().
>> +
>> +Enabling D-cache:
>> +- Make sure CONFIG_SYS_ICACHE_OFF is not set and call dcache_enable().
>               ^
> Maybe you will prefer to check for CONFIG_SYS_DCACHE_OFF ?

Yes. That's a typo. Will fix it. Thank you for pointing it out.

best regards,
Aneesh