[PATCH v5 2/2] arm64: dts: rockchip: add support for Radxa ROCK Pi E v3.0

[FUKAUMI Naoki]

Hi,

On 8/18/24 04:51, Dragan Simic wrote:
> On 2024-08-17 21:28, Dragan Simic wrote:
>> Hello Fukaumi,
>>
>> On 2024-08-17 00:20, FUKAUMI Naoki wrote:
>>> On 8/17/24 07:11, Heiko Stübner wrote:
>>>> Am Freitag, 16. August 2024, 23:34:29 CEST schrieb FUKAUMI Naoki:
>>>>> Radxa ROCK Pi E v3.0 is a compact networking SBC[1] using the Rockchip
>>>>> RK3328 chip that ships in a number of RAM/eMMC/WiFi/BT configurations:
>>>>>
>>>>> - Rockchip RK3328 SoC
>>>>> - Quad A53 CPU
>>>>> - 512MB/1GB/2GB DDR4 RAM
>>> (snip)
>>>> can you please describe what is different in that v3 board?
>>>> Describing what is different to require a separate board should've been
>>>> part of the commit message.
>>>>
>>>> Because from those changes, the bottom line currently seems to be
>>>> the same board with swapped mmc aliases?
>>>
>>> it's new board which uses DDR4 RAM (instead of DDR3 RAM on Pi E).
>>> different bootloader (U-Boot) is required.
>>>
>>> adding v3 dts seems not to be so important for Linux, but it's very
>>> important for U-Boot and OpenWrt(it includes bootloader for
>>> distributed binary).
>>
>> Aren't there different methods that allow such board variants to be
>> supported in U-Boot, with no need for a separate DT in the kernel?
>> IIRC, there are already more than a few examples of such board variants,
>> which require different DRAM initialization, which is covered in U-Boot
>> by providing different builds that use the same DT.
> 
> As an example, please have a look at the following files in U-Boot:
> 
> - arch/arm/dts/rk3399-nanopi-m4-u-boot.dtsi
> - arch/arm/dts/rk3399-nanopi-m4-2gb-u-boot.dtsi
> - configs/nanopi-m4-rk3399_defconfig
> - configs/nanopi-m4-2gb-rk3399_defconfig
> 
> Basically, there's no need for separate DTs in the kernel, just to support
> board variants with different DRAM types in U-Boot.

OpenWrt firmware upgrading tool (sysupgrade) refers "compatible" string 
to validate new firmware file is surely "for this board".

currently both Pi E dts have "radxa,rockpi-e", it makes flashing wrong 
firmware (include bootloaer, U-Boot) possible.

Radxa ROCK Pi E v1.x(DDR3) and ROCK Pi E v3(DDR4) are different 
incompatible boards, it must have different "compatible" string.

Best regards,

--
FUKAUMI Naoki
Radxa Computer (Shenzhen) Co., Ltd.