Re: [PATCH 2/3] ARM: IMX8MP: add initial support for Variscite DT8MCustomBoard with iMX8MP

[Kopfensteiner_Michael <michael.kopfensteiner@vahle.com>]

Hi Sasha,

thanks for your remarks on my patches. I agree with your comments.
I will rework the patches and submit a second version soon.

I added a small reply to the memory node remark to point out,
that I have no possibility to test my solution with other hardware
configurations and I am unsure whether I choose the best solution.

On Tue, Feb 21, 2023 at 10:20AM +0100, Sascha Hauer wrote:

[snip]

>> diff --git a/arch/arm/dts/imx8mp-var-dart-dt8mcustomboard.dts b/arch/arm/dts/imx8mp-var-dart-dt8mcustomboard.dts
>> new file mode 100644
>> index 0000000000..704289aa0b
>> --- /dev/null
>> +++ b/arch/arm/dts/imx8mp-var-dart-dt8mcustomboard.dts
>> @@ -0,0 +1,680 @@
>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +/*
>> + * Copyright 2019 NXP
>> + * Copyright 2020-2021 Variscite Ltd.
>> + * Copyright 2023 VAHLE Automation GmbH
>> + */
>> +
>> +#include "imx8mp-var-dart.dtsi"
>> +
>> +/ {
>> +     model = "Variscite DART-MX8M-PLUS on DT8MCustomBoard 2.x";
>> +
>> +     // use the memory controller instead
>> +     /delete-node/ memory@40000000;
>
> Better don't add this node to the dtsi file. Is the memory size detected
> correctly? The dtsi file describes 6 GiB of memory which is rather
> unusual. Is that what your board has?
>

I will delete the memory node.

As for the memory size:
Those modules are sold with RAM ranging from 1 to 8 GiB, my module actually
has 4GiB of RAM. The dtsi used was taken from Variscites provided linux sources.
Hence I thought it might be nice to rely on the memory controller to figure the actual
configuration out. I ran "memtest" successfully and used "devinfo mem0" to
validate, that it does see 4GiB of RAM for this node.
But I haven't checked whether some other RAM size option gets detected correctly
as well, as I only have this one SOM at hand.

>> +&edacmc {
>> +     status = "okay";
>> +};
>
> You can drop this. It's already enabled in imx8mp.dtsi.
>

[snip]

By the way, I have base those patches on the "next" branch, but I realized
that I have no clue what is preferred by the project's maintainers.
Shall I base those patches on "master" instead?

Michael