linux-kernel - Re: [PATCH 5/8] riscv: dts: spacemit: Add dma bus and PDMA node for K1 SoC

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Message-ID: <CAH1PCMa8DukTxxRoWBUV22zTFnSa-4pLkZjffXO2Z9s8dtpiMg@mail.gmail.com>
Date: Sat, 14 Jun 2025 11:33:08 +0800
From: Guodong Xu <guodong@...cstar.com>
To: Yixun Lan <dlan@...too.org>
Cc: Vivian Wang <uwu@...m.page>, vkoul@...nel.org, robh@...nel.org, krzk+dt@...nel.org, 
	conor+dt@...nel.org, paul.walmsley@...ive.com, palmer@...belt.com, 
	aou@...s.berkeley.edu, alex@...ti.fr, p.zabel@...gutronix.de, drew@...7.com, 
	emil.renner.berthing@...onical.com, inochiama@...il.com, 
	geert+renesas@...der.be, tglx@...utronix.de, hal.feng@...rfivetech.com, 
	joel@....id.au, duje.mihanovic@...le.hr, Ze Huang <huangze@...t.edu.cn>, 
	elder@...cstar.com, dmaengine@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org, 
	spacemit@...ts.linux.dev
Subject: Re: [PATCH 5/8] riscv: dts: spacemit: Add dma bus and PDMA node for
 K1 SoC

Hi, Yixun

On Fri, Jun 13, 2025 at 9:22 PM Yixun Lan <dlan@...too.org> wrote:
>
> Hi Vivian, Guodong,
>
> On 11:06 Fri 13 Jun     , Vivian Wang wrote:
> > Hi Guodong,
> >
> > On 6/11/25 20:57, Guodong Xu wrote:
> > > <snip>
> > >
> > > -                   status = "disabled";
> > > +           dma_bus: bus@4 {
> > > +                   compatible = "simple-bus";
> > > +                   #address-cells = <2>;
> > > +                   #size-cells = <2>;
> > > +                   dma-ranges = <0x0 0x00000000 0x0 0x00000000 0x0 0x80000000>,
> > > +                                <0x1 0x00000000 0x1 0x80000000 0x3 0x00000000>;
> > > +                   ranges;
> > >             };
> >
> > Can the addition of dma_bus and movement of nodes under it be extracted
> > into a separate patch, and ideally, taken up by Yixun Lan without going
> > through dmaengine? Not specifically "dram_range4", but all of these
> > translations affects many devices on the SoC, including ethernet and
> > USB3. See:
> Right, we've had an offline discussion, and agreed on this - have *bus
> patches separated and let other patches depend on it.
>
> But seems Guodong failed to do this or just sent out an old version
> of the PDMA patch?

Hi, Yixun

I realized that there is some sort of discrepancy between our understanding
from the offline discussion. With the information I put in the other email
earlier today, do you still think we should submit one patch which
covers all 6 seperated memory mapping buses for k1.dtsi?

Let me know what do you think. Thank you.

BR,
Guodong

>
> >
> > https://lore.kernel.org/all/20250526-b4-k1-dwc3-v3-v4-2-63e4e525e5cb@whut.edu.cn/
> > https://lore.kernel.org/all/20250613-net-k1-emac-v1-0-cc6f9e510667@iscas.ac.cn/
> >
> > (I haven't put eth{0,1} under dma_bus5 because in 6.16-rc1 there is
> > none, but ideally we should fix this.)
> >
> > DMA address translation does not depend on PDMA. It would be best if we
> > get all the possible dma-ranges buses handled in one place, instead of
> > everyone moving nodes around.
> >
> I agree
>
> > @Ze Huang: This affects your "MBUS" changes as well. Please take a look,
> > thanks.
> >
> > >
> > >             gpio: gpio@...19000 {
> > > @@ -792,3 +693,124 @@ pwm19: pwm@...22c00 {
> > >             };
> > >     };
> > >  };
> > > +
> > > +&dma_bus {
> > >
> > > <snip>
> >
>
> --
> Yixun Lan (dlan)