Re: [PATCH v2] arm64: dts: pinephone: Add pstore support for PinePhone A64

["Jernej Škrabec" <jernej.skrabec@gmail.com>]

Hi Andrey,

send new revision as standalone e-mail, not as reply to old discussion.

Dne torek, 22. avgust 2023 ob 11:23:58 CEST je Andrey Skvortsov napisal(a):
> This patch reserves some memory in the DTS and sets up a
> pstore device tree node to enable pstore support.
> 
> In general any DRAM address, that isn't overwritten during a boot is
> suitable for pstore.
> 
> Range from 0x40000000 - 0x50000000 is heavily used by u-boot for
> internal use and to load kernel, fdt, fdto, scripts, pxefile and ramdisk
> later in the boot process. Ramdisk start address is 0x4FF00000,
> initramfs for kernel with some hacking features and debug info enabled
> can take more than 100Mb and final address will be around 0x58000000.
> Address 0x61000000 will most likely not overlap with that.

There are other bootloaders as U-Boot, especially on PinePhone. Are you sure 
it works there too? What about U-Boot configuration, will those addresses still 
be used if configuration is changed?

Best regards,
Jernej

> 
> Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
> ---
> 
> Changes in v2:
>  - Update commit description with information about why this base address is
> used.
> 
>  .../boot/dts/allwinner/sun50i-a64-pinephone.dtsi | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi
> b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi index
> 87847116ab6d..84f9410b0b70 100644
> --- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi
> +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi
> @@ -19,6 +19,22 @@ aliases {
>  		serial0 = &uart0;
>  	};
> 
> +	reserved-memory {
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		ranges;
> +
> +		pstore_mem: ramoops@61000000 {
> +			compatible = "ramoops";
> +			reg = <0x61000000 0x100000>;
> +			record-size = <0x20000>;
> +			console-size = <0x20000>;
> +			ftrace-size = <0x20000>;
> +			pmsg-size = <0x20000>;
> +			ecc-size = <16>;
> +		};
> +	};
> +
>  	backlight: backlight {
>  		compatible = "pwm-backlight";
>  		pwms = <&r_pwm 0 50000 PWM_POLARITY_INVERTED>;