[U-Boot] [PATCH v3 4/7] armv8: ls1043ardb: Use static DDR setting for SPL boot

[York Sun]

On 09/29/2017 09:06 AM, Łukasz Majewski wrote:
> Hi York,
> 
>> On 09/29/2017 12:44 AM, Łukasz Majewski wrote:
>>> Hi York,
>>>
>>>> This board has soldered DDR chips. To reduce the SPL image size,
>>>> use static DDR setting instead of dynamic DDR driver.
>>>
>>> I'm just wondering - since your board supports FIT in SPL, maybe it
>>> would be good to have a binary blob with DDR RAM settings embedded into it?
>>>
>>> Then you would be able to provide "hardcoded" SDRAM setup via it?
>>> In this way it could be easily replaceable?
>>>
>>
>> Lukasz,
>>
>> It sounds reasonable but doesn't work for our platforms. The limitation
>> is the static RAM. In order to load anything, we need to have some
>> memory. Lacking of memory is the exact reason I have to use static DDR
>> setting. I have to make room for other drivers in SPL.
> 
> I rather thought about:
> 
> Creating FIT image with firmware property, in which you will have 1:1 
> binary image for DDR controller registers (e.g. 256B).
> 
> Then you could store this image to non-volatile memory and read it from 
> SPL (just copy values to registers).
> 
> In that way you would be able to switch different configurations for 
> different memories (DDR2/DDR3/, 1066, 1333 MHz) without the need to 
> replace u-boot/SPL.
> 

Lukasz,

I understand your suggestion. I was trying to say that I don't have any
spare room to load the FIT into before I have DDR initialized. I only
have limited SRAM.

York