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

[Dragan Simic <dsimic@manjaro.org>]

Hello Naoki,

On 2024-08-18 00:30, Dragan Simic wrote:
> 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.

As a separate thought, is there some way to detect the actual ROCK Pi E
board variant at runtime, using some GPIO line, ADC readout, or 
something
similar?  That would help with making it possible to have a single 
U-Boot
build for both board variants.