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 <lchen@ambarella.com>
To: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc: "Lad Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	"Kishon Vijay Abraham I" <kishon@ti.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Marek Vasut" <marek.vasut+renesas@gmail.com>,
	"Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas.com>,
	"Rob Herring" <robh@kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org"
	<linux-renesas-soc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Biju Das" <biju.das.jz@bp.renesas.com>
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
Date: Thu, 10 Feb 2022 05:54:26 +0000	[thread overview]
Message-ID: <PH7PR19MB5562CE44BBDF09B2ECD30BEDA02F9@PH7PR19MB5562.namprd19.prod.outlook.com> (raw)
In-Reply-To: <CA+V-a8tEwOR-r=+KDe2DhpTMwhXPTgbZYgOWepST3mnhBL_Hag@mail.gmail.com>

Hi Prabhakar,

> -----Original Message-----
> From: Lad, Prabhakar [mailto:prabhakar.csengg@gmail.com]
> 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@vger.kernel.org; linux-renesas-
> soc@vger.kernel.org; linux-kernel@vger.kernel.org; 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@ambarella.com> 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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