RE: [PATCH v3 7/9] arm64: dts: renesas: rzg3s-smarc-som: Update dma-ranges for PCIe

Biju Das
2025-07-09T05:08:56Z

Hi Claudiu Beznea,

> -----Original Message-----
> From: Claudiu Beznea <claudiu.beznea@tuxon.dev>
> Sent: 08 July 2025 11:10
> Subject: Re: [PATCH v3 7/9] arm64: dts: renesas: rzg3s-smarc-som: Update dma-ranges for PCIe
>
> Hi, Biju,
>
> On 07.07.2025 11:18, Biju Das wrote:
> > Hi Claudiu,
> >
> >> -----Original Message-----
> >> From: Claudiu <claudiu.beznea@tuxon.dev>
> >> Sent: 04 July 2025 17:14
> >> Subject: [PATCH v3 7/9] arm64: dts: renesas: rzg3s-smarc-som: Update
> >> dma-ranges for PCIe
> >>
> >> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> >>
> >> The first 128MB of memory is reserved on this board for secure area.
> >> Update the PCIe dma-ranges property to reflect this.
> >
> > I see R-Car PCIe dma-ranges[1] and [2] maps all possible DDR area supported by the SoC?
> > Do we need to make board specific as well there?
>
> I'm not familiar with R-Car, but if there are ranges reserved for other purposes, I think we should
> reflect it in board specific device trees.

Already Linux has this DDR info[1]. Linux provides DMA memory only from this region.

In your testing, have you faced any issue like system allocated DMA region other than [1]
and you don't want to use it, then the changes are ok??

Not sure, PCIe can work on internal memory such as SRAM?

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm64/boot/dts/renesas/rzg3s-smarc-som.dtsi?h=next-20250708#n31

Cheers,
Biju