[U-Boot] [PATCH][v4] powerpc/mpc85xx: SECURE BOOT- Add secure boot target for B4860QDS

[York Sun]

On 03/07/2014 10:54 AM, Scott Wood wrote:
> On Fri, 2014-03-07 at 10:30 -0800, York Sun wrote:
>> On 03/07/2014 05:23 AM, Aneesh Bansal wrote:
>>> Changes:
>>> 1. L2 cache is being invalidated by Boot ROM code for e6500 core.
>>>    So removing the invalidation from start.S
>>> 2. Clear the LAW and corresponding configuration for CPC. Boot ROM
>>>    code uses it as hosekeeping area.
>>> 3. For Secure boot, CPC is configured as SRAM and used as house
>>>    keeping area. This configuration is to be disabled once in uboot.
>>>    Earlier this disabling of CPC as SRAM was happening in cpu_init_r.
>>>    As a result cache invalidation function was getting skipped in
>>>    case CPC is configured as SRAM.This was causing random crashes.
>>>
>>> Signed-off-by: Aneesh Bansal <aneesh.bansal at freescale.com>
>>> ---
>>>  README                                     |  4 ++++
>>>  arch/powerpc/cpu/mpc85xx/cpu_init.c        | 27 ++++++++++++++++++++++-----
>>>  arch/powerpc/cpu/mpc85xx/start.S           |  3 ++-
>>>  arch/powerpc/include/asm/fsl_secure_boot.h |  6 ++++++
>>>  boards.cfg                                 |  1 +
>>>  5 files changed, 35 insertions(+), 6 deletions(-)
>>>
>>> Changes from v3:
>>> Renamed the macro to indicate CPC configured as SRAM at U-boot entry to
>>> CONFIG_SYS_CPC_SRAM 
>>
>> Aneesh,
>>
>> I understand you are trying to address the comment about when CPC needs to be
>> disabled before initializing as normal CPC. But introducing CONFIG_SYS_CPC_SRAM
>> seems even more confusing. Let's take one step back.
>>
>> CPC as SRAM can be used for many reasons. There is only one reason we should
>> keep it as SRAM, i.e. u-boot is indeed using SRAM as its final destination. For
>> all other usages, we can safely reconfigure it as normal CPC after u-boot
>> relocates itself into DDR. If u-boot's final destination is SRAM, it is a
>> RAMBOOT. Can we use this condition to deal with CPC?
> 
> Even if CPC is the final destination, shouldn't RAMBOOT imply that DDR
> has been initialized?

No. RAMBOOT implies u-boot shouldn't initialize RAM. There may be cases where
u-boot needs to run in SRAM without DDR. It doesn't matter if the RAM is SRAM or
DRAM.

York