RE: [EXT] [RFC PATCH 0/5] PCIe EPF support for internal DMAC handling and driver update for R-Car PCIe EP to support DMAC

From: Li Chen
Date: Thu Feb 10 2022 - 01:01:18 EST


Hi Prabhakar,

> -----Original Message-----
> From: Lad, Prabhakar [mailto:prabhakar.csengg@xxxxxxxxx]
> Sent: Wednesday, February 9, 2022 4:53 PM
> To: Li Chen
> Cc: Lad Prabhakar; Kishon Vijay Abraham I; Bjorn Helgaas; Lorenzo Pieralisi;
> Krzysztof Wilczyński; Arnd Bergmann; Greg Kroah-Hartman; Marek Vasut;
> Yoshihiro Shimoda; Rob Herring; linux-pci@xxxxxxxxxxxxxxx; linux-renesas-
> soc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Biju Das
> Subject: Re: [EXT] [RFC PATCH 0/5] PCIe EPF support for internal DMAC handling
> and driver update for R-Car PCIe EP to support DMAC
>
> Hi Chen-san,
>
> On Wed, Feb 9, 2022 at 4:48 AM Li Chen <lchen@xxxxxxxxxxxxx> wrote:
> >
> > Hi Prabhakar,
> >
> > > [0] https://urldefense.com/v3/__https://www.spinics.net/lists/linux-
> > >
> pci/msg92385.html__;!!PeEy7nZLVv0!yP0WqYs165riCjWRhZprjgMVVLfQLtkkPfv_
> > > R7XCoqkqgMsOyor90EZp0YAdxu0$
> >
> > Can your streaming DMA test case(-d) pass if you use EP's internal DMAC
> instead of external DMAC?
> >
> Sorry I don't quite get you here.
>
> This patch series adds support for EP to transfer using internal DMAC
> as no external DMAC is supported, so when "-d" option is passed and if
> EP has registered it has internal dmac it will use the same and run
> the pcitest.

Ok, in my case, read/write via external DMAC always get incorrect data, but read via internal DMAC is correct. Maybe this is our RTL's issue.

Regards,
Li

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