[U-Boot] [PATCH] armv8/ls1043a: Add the OCRAM initialization

[york sun]

On 10/23/2016 06:59 AM, Prabhakar Kushwaha wrote:
> Hi York,
>
>
>> -----Original Message-----
>> From: york sun
>> Sent: Saturday, October 22, 2016 1:39 AM
>> To: Prabhakar Kushwaha <prabhakar.kushwaha at nxp.com>; Pratiyush Srivastava
>> <pratiyush.srivastava at nxp.com>; u-boot at lists.denx.de; Mingkai Hu
>> <mingkai.hu at nxp.com>
>> Cc: Hou Zhiqiang <Zhiqiang.Hou at freescale.com>
>> Subject: Re: [PATCH] armv8/ls1043a: Add the OCRAM initialization
>>
>> On 10/16/2016 10:35 PM, Prabhakar Kushwaha wrote:
>>> Hi Mingkai,
>>>
>>>> -----Original Message-----
>>>> From: Pratiyush Srivastava [mailto:pratiyush.srivastava at nxp.com]
>>>> Sent: Wednesday, October 12, 2016 5:46 PM
>>>> To: u-boot at lists.denx.de
>>>> Cc: york sun <york.sun at nxp.com>; Prabhakar Kushwaha
>>>> <prabhakar.kushwaha at nxp.com>; Pratiyush Srivastava
>>>> <pratiyush.srivastava at nxp.com>; Hou Zhiqiang
>> <Zhiqiang.Hou at freescale.com>
>>>> Subject: [PATCH] armv8/ls1043a: Add the OCRAM initialization
>>>>
>>>> Clear the content to zero and the ECC error bit of OCRAM1/2.
>>>>
>>>> The OCRAM must be initialized to ZERO by the unit of 8-Byte before
>>>> accessing it, or else it will generate ECC error. And the IBR has
>>>> accessed the OCRAM before this initialization, so the ECC error
>>>> status bit should to be cleared.
>>>>
>>>> Signed-off-by: Pratiyush Srivastava <pratiyush.srivastava at nxp.com>
>>>> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou at freescale.com>
>>>> Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha at nxp.com>
>>>> ---
>>>
>>> This requirement is for both ls1043 and ls1088a.  was this patch taken care
>> during ls1043a upstreaming
>>> If not, how it is being taken care for ls1043a.  Same approach can be used for
>> ls1088a
>>>
>>
>> I wonder why we don't see ECC errors before this patch. We have LS1043A
>> boots on NAND, SD.
>>
>
> OCRAM has a requirement of initializing before first time "read".
> If user reads OCRAM before **initializing**; ECC error will come.  (u-boot is not handling this error for now).
>
> I can only guess the reason of not seeing this error as OCRAM never read before any write.
> Even in case of Stack, data is first written and then read.
>

Is there a case you want to read from OCRAM before writing anything to 
it? Why don't we need to do so for SPL or LSCH3?

York