[PATCH v5 1/2] arm: rmobile: Add RZ/G2[HMNE] SoC support

[Marek Vasut]

On 11/3/20 11:06 AM, Biju Das wrote:
> Hi Marek,

Hi,

[...]

>>> On the next version, I will send Renesas SoC identification driver,
>>> which supports caching family type which can be used to provide unique
>> identification for CPU type.
>>
>> Please make sure to check it on RCar2 as well, those use SPL and the SPL size
>> is quite limited.
> 
> Currently SoC identification driver is enabled only for RZ/G2 boards and support is added to both R-Car Gen3 and RZ/G2 devices.
> 
> For the disabled case, the UCLASS-SOC class functions are inlined to "NULL"  for soc_device_match and rest of the api's it is "-ENOSYS".
> 
> I agree, in future we need to add support for RCar2 as well, since we are going to add u-boot support for RZ/G1 devices.
> Please find the size details related to R-Car Gen2(by adding support for R-Car M2-W and RZ/G1M SoC).
> 
> There is increase of 944 bytes, for R-Car Gen2 device, if we enable Renesas SoC identification driver for Gen2 devices.
> 
> Current u-boot-sh/master
> -----------------------------------
> $ ls -al u-boot.bin
> -rw-r--r-- 1 biju biju 523001 Nov  3 09:16 u-boot.bin
> 
> Current u-boot-sh/master + SoC renesas driver (R-Car M2-W enabled only case)
> --------------------------------------------------------------------------------------------
> $ ls -al u-boot.bin
> -rw-r--r-- 1 biju biju 523945 Nov  3 09:47 u-boot.bin
> 
> If you agree, we will add support for Gen2 to SoC identification driver later. Currently there is no users for using it.
> Please let me know.

The problem on Gen2 isn't the size of u-boot.bin , but of 
spl/u-boot-spl.bin . That one is severely limited and I don't think it's 
realistic to add any sort of SoC identification driver into it. In fact, 
I think even the DM is somehow reduced in there.