Re: [PATCH 2/4] ARM: dts: qcom: apq8074-dragonboard: Set DMA as remotely controlled

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On 08/05/2023 11:32, Konrad Dybcio wrote:
> 
> 
> On 7.05.2023 21:07, Dmitry Baryshkov wrote:
>> Add the qcom,controlled-remotely property for the blsp2_bam
>> controller node. This board requires this, otherwise the board stalls
>> during the boot for some reason (most probably because TZ mishandles the
>> protection error and keeps on looping somewhere inside).
>>
>> Fixes: 62bc81792223 dts: msm8974: Add blsp2_bam dma node
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> ---
> Looks like a common theme.. sony-rhine boards also have the DMA
> enabled *and* need this property.. perhaps it's a SoC-wide (or
> at least SoC-and-fw-distribution-wide) issue?

This looks like a strange history. Especially granted 338d51889851 
("Revert "dts: msm8974: Add blsp2_bam dma node"") and d44cbb1e9ca3 
("Revert "Revert "dts: msm8974: Add blsp2_bam dma node""")

And, of course, 
https://lore.kernel.org/linux-arm-msm/CAJAp7Oi33=kraAiU337JdFJZbuKZEVoCtY4FfAv_RgiWVmz+sw@mail.gmail.com/

Note, 338d51889851 mentions non-dragonboard boards. This makes me think 
that for some of the dragonboards/firmware combos this device was 
working as is, without controlled remotely. I could not get 'the latest 
bootloader package' (if there was one), so I'm stuck with what I have on 
my board. However there is no guarantee that it is the latest and 
greatest stuff.

Thus said, for this patch I decided to follow the rhino example and add 
this to the board file. Unless Bjorn (or anybody else remembering those 
times) can advise us.

> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> 
> Konrad
>>   arch/arm/boot/dts/qcom-apq8074-dragonboard.dts | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/qcom-apq8074-dragonboard.dts b/arch/arm/boot/dts/qcom-apq8074-dragonboard.dts
>> index 1345df7cbd00..6b047c679370 100644
>> --- a/arch/arm/boot/dts/qcom-apq8074-dragonboard.dts
>> +++ b/arch/arm/boot/dts/qcom-apq8074-dragonboard.dts
>> @@ -23,6 +23,10 @@ &blsp1_uart2 {
>>   	status = "okay";
>>   };
>>   
>> +&blsp2_dma {
>> +	qcom,controlled-remotely;
>> +};
>> +
>>   &blsp2_i2c5 {
>>   	status = "okay";
>>   	clock-frequency = <200000>;

-- 
With best wishes
Dmitry