[RFC] rockchip: add support for Radxa ROCK Pi E v3.0 which uses DDR4 SDRAM

[Dragan Simic]

+Cc: heiko at sntech.de
+Cc: krzk at kernel.org

Hello Peter and Fukaumi,

On 2024-06-23 15:08, Peter Robinson wrote:
> On Sun, 23 Jun 2024 at 13:21, Dragan Simic <dsimic at manjaro.org> wrote:
>> On 2024-06-23 06:15, FUKAUMI Naoki wrote:
>> > rk3328-rock-pi-e-v3.dts is identical to rk3328-rock-pi-e.dts in
>> > upstream. only difference between v3.0 and prior ver. is, using
>> > rk3328-sdram-ddr4-666.dtsi instead of rk3328-sdram-ddr3-666.dtsi.
>> 
>> I think you'll need to get the device tree resolved on the Linux
>> kernel side first, and then imported into U-Boot following the
>> rules of the OF_UPSTREAM approach.
> 
> I think the question was more "given the only difference between the
> two is the memory is there a way we can do a single U-Boot build that
> supports both" and I think the answer to that is unfortunately no,
> even if the DT, config etc are all the same. I would be interested if
> you come up with a solution as I have a couple of devices like this.

Good point.  Maybe we could employ an approach similar to how the
bad CPU cores will be disabled by U-Boot on RK3582.  Though, is it
even possible to detect the board revision on the ROCK Pi E, e.g.
by reading the statuses of some GPIO lines that encode the board
revision?  I went quickly through the v3.0 schematic and haven't
spotted anything like that.

>> > here is console output from ROCK Pi E v3.0:
>> >
>> > ```
>> > U-Boot TPL 2024.07-rc4-dirty (Jun 23 2024 - 12:53:09)
>> > DDR4, 333MHz
>> > BW=32 Col=10 Bk=4 BG=2 CS0 Row=16 CS=1 Die BW=16 Size=2048MB
>> > Trying to boot from BOOTROM
>> > Returning to boot ROM...
>> >
>> > U-Boot SPL 2024.07-rc4-dirty (Jun 23 2024 - 12:53:09 +0900)
>> > Trying to boot from MMC2
>> > ```
>> >
>> > there is an another way which can share same u-boot-rockchip.bin
>> > between v3 and prior, using ddr blob from Rockchip instead of TPL in
>> > U-Boot. is it acceptable?
>> >
>> > Signed-off-by: FUKAUMI Naoki <naoki at radxa.com>
>> > ---
>> >  arch/arm/dts/rk3328-rock-pi-e-v3-u-boot.dtsi |   43 +
>> >  arch/arm/dts/rk3328-rock-pi-e-v3.dts         |  445 ++++
>> >  arch/arm/dts/rk3328.dtsi                     | 1943 ++++++++++++++++++
>> >  configs/rock-pi-e-v3-rk3328_defconfig        |   97 +
>> >  4 files changed, 2528 insertions(+)
>> >  create mode 100644 arch/arm/dts/rk3328-rock-pi-e-v3-u-boot.dtsi
>> >  create mode 100644 arch/arm/dts/rk3328-rock-pi-e-v3.dts
>> >  create mode 100644 arch/arm/dts/rk3328.dtsi
>> >  create mode 100644 configs/rock-pi-e-v3-rk3328_defconfig

[snip]