[U-Boot] [PATCH 2/2] powerpc/mpc85xx: modify erratum A007212

[York Sun]

On 09/25/2014 10:55 PM, Zhao Qiang-B45475 wrote:
> 
> On 9/26/14 1:01 PM, York Sun wrote:
> 
>> -----Original Message-----
>> From: Sun York-R58495
>> Sent: Friday, September 26, 2014 1:01 PM
>> To: Zhao Qiang-B45475; u-boot at lists.denx.de
>> Cc: Xie Xiaobo-R63061; Zhao Qiang-B45475
>> Subject: Re: [PATCH 2/2] powerpc/mpc85xx: modify erratum A007212
>>
>> On 9/25/14 9:37 PM, "Zhao Qiang" <B45475 at freescale.com> wrote:
>>
>>> T2080 v1.0 has this errata while v1.1 has fixed this errata by
>>> hardware, add a new function to check the SVR_SOC_VER, SVR_MAJ and
>>> SVR_MIN first, if the cpu is T2080 and version is not v1.0, doesn't run
>>> the a007212 errata_workaround.
>>>
>>> Signed-off-by: Zhao Qiang <B45475 at freescale.com>
>>> ---
>>
>>
>> Qiang,
>>
>> I don't agree with your analysis.
>>
>> This workaround has two parts. One part is to to disable DDR PLL in RCW.
>> The second part is to detect DDR PLL is disabled and to implement the
>> software workaround to bring DDR up. U-boot has the second part, it is
>> safe to apply to all versions for affected SoC. I put in the comments.
>> Your patch detects the SVR and decide if the workaround should be applied.
>> This is wrong. It should detect if DDR PLL is disabled. In case an old
>> RCW is used, you don't want to end up with a dead board because DDR is
>> disabled.
> 
> OK , got it , I will modify it for v2.
> Thanks for you comment.
> 

Qiang,

I don't think you even need a patch for this. The logic for u-boot code is:

Regardless of the SVR, the workaround is not be applied if RCW doesn't disable
DDR PLL.
Regardless of the SVR, the workaround is and should be applied if RCW disables
DDR PLL.

York