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

[Dragan Simic <dsimic@manjaro.org>]

On 2024-08-17 22:28, FUKAUMI Naoki wrote:
> On 8/18/24 05:12, Dragan Simic wrote:
>> On 2024-08-17 22:04, FUKAUMI Naoki wrote:
>>> On 8/18/24 04:51, Dragan Simic wrote:
>>>> On 2024-08-17 21:28, Dragan Simic wrote:
>>>>> 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.
>> 
>> Could you, please, explain what's the actual issue with OpenWrt?  I 
>> did
>> read some GitHub issue that described it, IIRC, but I was unable to 
>> fully
>> understand what's the underlying issue.
> 
> $ wget
> https://downloads.openwrt.org/snapshots/targets/rockchip/armv8/openwrt-rockchip-armv8-radxa_rock-pi-e-ext4-sysupgrade.img.gz
> $ strings
> openwrt-rockchip-armv8-radxa_rock-pi-e-ext4-sysupgrade.img.gz | grep
> metadata
> {  "metadata_version": "1.1", "compat_version": "1.0",
> "supported_devices":["radxa,rock-pi-e"], "version": { "dist":
> "OpenWrt", "version": "SNAPSHOT", "revision": "r27160-b72c4b5386",
> "target": "rockchip/armv8", "board": "radxa_rock-pi-e" } }
> 
> $ wget
> https://downloads.openwrt.org/snapshots/targets/rockchip/armv8/openwrt-rockchip-armv8-radxa_rock-pi-e-v3-ext4-sysupgrade.img.gz
> $ strings
> openwrt-rockchip-armv8-radxa_rock-pi-e-v3-ext4-sysupgrade.img.gz |
> grep metadata
> {  "metadata_version": "1.1", "compat_version": "1.0",
> "supported_devices":["radxa,rock-pi-e-v3"], "version": { "dist":
> "OpenWrt", "version": "SNAPSHOT", "revision": "r27160-b72c4b5386",
> "target": "rockchip/armv8", "board": "radxa_rock-pi-e-v3" } }
> 
> since they are incompatible firmware, it needs to have different
> "supported_devices" string. if both are "radxa,rockpi-e", firmware
> validation will not work correctly.
> 
> (currently both values are wrong, it needs to be fixed, but it's 
> another story)
> 
>>> Radxa ROCK Pi E v1.x(DDR3) and ROCK Pi E v3(DDR4) are different
>>> incompatible boards, it must have different "compatible" string.
>> 
>> Well, the above-mentioned Nano Pi M4 boards share the same DT and the 
>> same
>> "compatible" value, because for all consumers of the DT, except for 
>> U-Boot
>> that can already handle the differences, they are the same boards.
> 
> (un)fortunately Nano Pi M4 boards seems not to be supported by OpenWrt
> 
>  https://downloads.openwrt.org/snapshots/targets/rockchip/armv8/

Thanks for the explanations.  As discussed further in #linux-rockchip
on Libera.Chat, we do need a general solution for this issue, which 
would
get us covered for all the board variants that use different DRAM chips,
which are currently known to U-Boot only.

I'll keep thinking about this in the next couple of days, and I'll come
back with an update.