linux-kernel - Re: [PATCH 4/8] dma: mmp_pdma: Add SpacemiT PDMA support with 64-bit addressing

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Message-ID: <CAH1PCMYL57eEVyx7qy3offcsuKsN23qO73H+YTnffZe4kBxzMA@mail.gmail.com>
Date: Thu, 19 Jun 2025 10:37:52 +0800
From: Guodong Xu <guodong@...cstar.com>
To: Vinod Koul <vkoul@...nel.org>
Cc: robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org, dlan@...too.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, 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 4/8] dma: mmp_pdma: Add SpacemiT PDMA support with 64-bit addressing

On Tue, Jun 17, 2025 at 2:02 PM Vinod Koul <vkoul@...nel.org> wrote:
>
> On 11-06-25, 20:57, Guodong Xu wrote:
> > Extend the MMP PDMA driver to support SpacemiT PDMA controllers with
> > 64-bit physical addressing capabilities, as used in the K1 SoC. This
> > change introduces a flexible architecture that maintains compatibility
> > with existing 32-bit Marvell platforms while adding 64-bit support.
> >
> > Key changes:
> > - Add struct mmp_pdma_config to abstract platform-specific behaviors
> > - Implement 64-bit address support through:
> >   * New high address registers (DDADRH, DSADRH, DTADRH)
> >   * DCSR_LPAEEN bit for Long Physical Address Extension mode
> >   * Helper functions for 32/64-bit address handling
> > - Add "spacemit,pdma-1.0" compatible string with associated config
> > - Extend descriptor structure to support 64-bit addresses
> > - Refactor address handling code to be platform-agnostic
> > - Add proper DMA mask configuration for both 32-bit and 64-bit modes
> >
> > The implementation uses a configuration-based approach to keeps all
> > platform-specific code isolated in config structures. It maintains clean
> > separation between 32-bit and 64-bit code paths, provides consistent
> > API for both addressing modes and preserves backward compatibility.
>
> I would ask for this to be split, first to to driver changes for adding
> new ops and then adding new soc support. This way the two changes are
> independent

Hi, Vinod

Thank you for the feedback. I agree with that.
I'll send v2 with this split approach.

-
Guodong

>
> --
> ~Vinod