Re: [PATCH 7/8] arm64: dts: s32g2: add memory nodes for evb and rdb2

Andreas Färber
2021-08-12T18:25:04Z

Hi Chester et al.,

On 05.08.21 08:54, Chester Lin wrote:
> Add memory nodes for S32G-VNP-EVB and S32G-VNP-RDB2 since they have fixed
> RAM size.

You can drop "since they have fixed RAM size" - if they didn't, you
would simply choose the lowest size and rely on the bootloader (U-Boot)
to overwrite it with the actually detected size.

Please expand why this patch is separate - BSP based, I assume?

>
> Signed-off-by: Chester Lin <clin@suse.com>
> ---
> arch/arm64/boot/dts/freescale/s32g274a-evb.dts | 8 ++++++++
> arch/arm64/boot/dts/freescale/s32g274a-rdb2.dts | 8 ++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/freescale/s32g274a-evb.dts b/arch/arm64/boot/dts/freescale/s32g274a-evb.dts
> index a1ae5031730a..cd41f0af5dd8 100644
> --- a/arch/arm64/boot/dts/freescale/s32g274a-evb.dts
> +++ b/arch/arm64/boot/dts/freescale/s32g274a-evb.dts
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0-or-later OR MIT
> /*
> * Copyright (c) 2021 SUSE LLC
> + * Copyright 2019-2020 NXP

@NXP: Please review year, alignment. Do any Signed-off-bys apply?

> */
>
> /dts-v1/;
> @@ -14,6 +15,13 @@ / {
> chosen {
> stdout-path = "serial0:115200n8";
> };
> +
> + memory@80000000 {
> + device_type = "memory";
> + /* 4GB RAM */

This looks strange to me - either put /* 4 GiB RAM */ before the node,
three lines above, and/or append comment /* 2 GiB */ on each line below.
Note the space, and suggest to be precise about factor 1024 vs. 1000.

> + reg = <0 0x80000000 0 0x80000000>,

Note that this gives you the range to use for the .dtsi /soc node:
Address 0x0 with size 0x80000000 gets mapped to 0x0 0x0, excluding the
upper 0x80000000 for the RAM here. Or address 0x0 0x0 for two /soc cells
if there are high-memory peripherals.

> + <8 0x80000000 0 0x80000000>;

Maybe use 0x8 here and 0x0 above? (second 0 stays same, so don't mind)

> + };
> };
>
> &uart0 {
> diff --git a/arch/arm64/boot/dts/freescale/s32g274a-rdb2.dts b/arch/arm64/boot/dts/freescale/s32g274a-rdb2.dts
> index b2faae306b70..8fbbf3b45eb8 100644
> --- a/arch/arm64/boot/dts/freescale/s32g274a-rdb2.dts
> +++ b/arch/arm64/boot/dts/freescale/s32g274a-rdb2.dts
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0-or-later OR MIT
> /*
> * Copyright (c) 2021 SUSE LLC
> + * Copyright 2019-2020 NXP

@NXP: 2021?

> */
>
> /dts-v1/;
> @@ -14,6 +15,13 @@ / {
> chosen {
> stdout-path = "serial0:115200n8";
> };
> +
> + memory@80000000 {
> + device_type = "memory";
> + /* 4GB RAM */
> + reg = <0 0x80000000 0 0x80000000>,
> + <8 0x80000000 0 0x80000000>;
> + };

Same comments as for EVB.

> };
>
> &uart0 {

Regards,
Andreas

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