Re: [PATCH v2 1/3] ARM: dts: rockchip: Add psci for rk3036

[Alex Bee <knaerzche@gmail.com>]

Hi Andy,

Am 22.12.23 um 11:37 schrieb Andy Yan:
> Hi Alex,
>
> On 12/21/23 23:58, Alex Bee wrote:
>> Hi Andy,
>>
>> Am 21.12.23 um 02:07 schrieb Andy Yan:
>>> Hi Alex:
>>>
>>> On 12/20/23 19:16, Alex Bee wrote:
>>>> Hi Andy,
>>>> Am 18.12.23 um 11:55 schrieb Andy Yan:
>>>>> From: Andy Yan <andy.yan@rock-chips.com>
>>>>>
>>>>> The system will hang at bringup secondary CPUs
>>>>> without psci node.
>>>>>
>>>>> Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
>>>>>
>>>>> ---
>>>>>
>>>>> (no changes since v1)
>>>>>
>>>>>   arch/arm/boot/dts/rockchip/rk3036.dtsi | 5 +++++
>>>>>   1 file changed, 5 insertions(+)
>>>>>
>>>>> diff --git a/arch/arm/boot/dts/rockchip/rk3036.dtsi 
>>>>> b/arch/arm/boot/dts/rockchip/rk3036.dtsi
>>>>> index 78686fc72ce6..5344803442a1 100644
>>>>> --- a/arch/arm/boot/dts/rockchip/rk3036.dtsi
>>>>> +++ b/arch/arm/boot/dts/rockchip/rk3036.dtsi
>>>>> @@ -67,6 +67,11 @@ display-subsystem {
>>>>>           ports = <&vop_out>;
>>>>>       };
>>>>> +    psci {
>>>>> +        compatible = "arm,psci-1.0";
>>>>> +        method = "smc";
>>>>> +    };
>>>>> +
>>>> I don't think that's an good idea. 
>>>
>>> Why?
>> It's only what I've been told before: We shoudn't add properties which
>> depend on non-upstream software (if an upstream alternative exists). 
>> Also
>
>> I'm not sure what happens if somebody doesn't use downstream bootloader
>> and PSCI can't be found: Would the board still be able to boot?
>
> The psci is released herel[0].
> And also, there are only two rk3036 based boards in mainline:
> rk3036-evb,rk3036-keylin, both of them from rockchip.
> And the mainline support of these boards broken from linux 5.7(2020, 
> see PATCH 3),
> no one report this broken until I try to run this board now.
> So maybe there is no such somebody will run into this situation.
>
>
> [0]https://github.com/rockchip-linux/rkbin/tree/master/bin/rk30
>
Yeah sure, there are binary release for downstream optee implementations,
but the won't work with upstream u-boot, since they are using a calling
convention different from upstream optee os. I tried to add support for
those, but it was rejected [0].

Upstream bootflow doesn't implement/need PSCI as it uses a SMP bringup
method which is done in kernel only (see enable-method in cpu section). I
guess that it doesn't work for you is most likely because the downstream
tee os makes the cpu registers the upstream enable-method uses only
accessible in a higher exception level.

I can undust my RK3036 evb board during christmas holidays and check whats
broken for RK3036 in u-boot. Everything was working fine (including SMP
bringup w/o PSCI and upstream u-boot) when I was adding VPU support in 5.14
[1]. I likely booted from TF-card rather than eMMC.

[0] 
https://patchwork.ozlabs.org/project/uboot/patch/20230718145715.1280201-6-knaerzche@gmail.com/
[1] 
https://patchwork.kernel.org/project/linux-rockchip/patch/20210527154455.358869-11-knaerzche@gmail.com/

Nice holidays!

Alex

>>>
>>>> You most likely need that because you have downstream bootloader 
>>>> installed on this board. PSCI implementation takes place in TEE-OS 
>>>> for Rockchips ARM SoCs. There is no support for RK3036 in upstream 
>>>> op-tee OS. It's pretty much the same for RK3128 and RK3288.
>>>> If you use upstream u-boot it should be good as-is.
>>>
>>> Unfortunately, upstream u-boot also cannot boot up on this board.
>>> At present, I haven't had time to debug what is going on.
>>>
>>> Another reason I want to use downstream u-boot it is: I try run
>>> this board with mainline just because i want to test some community
>>> patches about inno-hdmi driver, as you said "the inno-hdmi driver 
>>> currently gets a lot of attention"[0]
>>>
>> Thanks for helping testing this.
>>
>> Alex
>>
>>> With a downstream u-boot I can easy switch between upstream kernel 
>>> and downstream kernel(no need to replace other components)
>>> if I found some function is not work as expected.
>>>
>>>
>>> [0]https://patchwork.kernel.org/project/linux-rockchip/cover/20231219170100.188800-1-knaerzche@gmail.com/ 
>>>
>>>>
>>>> Alex
>>>>>       timer {
>>>>>           compatible = "arm,armv7-timer";
>>>>>           arm,cpu-registers-not-fw-configured;
>>>>
>>>>
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