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

[Frank Li <frank.li@nxp.com>]

> -----Original Message-----
> From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> Sent: Wednesday, March 2, 2022 11:18 AM
> To: Frank Li <frank.li@nxp.com>
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>; 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 <linux-pci@vger.kernel.org>; Linux-Renesas <linux-renesas-
> soc@vger.kernel.org>; LKML <linux-kernel@vger.kernel.org>; Biju Das
> <biju.das.jz@bp.renesas.com>
> Subject: [EXT] Re: [RFC PATCH 0/5] PCIe EPF support for internal DMAC
> handling and driver update for R-Car PCIe EP to support DMAC
> 
> Caution: EXT Email
> 
> Hi Frank,
> 
> On Wed, Mar 2, 2022 at 3:42 PM Frank Li <frank.li@nxp.com> wrote:
> >
> >
> >
> > > -----Original Message-----
> > > From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> > > Sent: Thursday, February 10, 2022 3:24 AM
> > > To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > 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 <linux-pci@vger.kernel.org>; Linux-Renesas
> > > <linux-renesas-soc@vger.kernel.org>; LKML <linux-
> kernel@vger.kernel.org>;
> > > Biju Das <biju.das.jz@bp.renesas.com>
> > > Subject: [EXT] Re: [RFC PATCH 0/5] PCIe EPF support for internal DMAC
> > > handling and driver update for R-Car PCIe EP to support DMAC
> >
> > I use standard DMA engine API to implement Designware PCIE EP embedded
> DMA support.
> > Please check
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kern
> el.org%2Fall%2F20220302032646.3793-3-
> Frank.Li%40nxp.com%2FT%2F&amp;data=04%7C01%7Cfrank.li%40nxp.com%7C0e2e5fe8f
> d224076afb208d9fc70aa16%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637818
> 383096028914%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLC
> JBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=DCDX%2BYEVFsPOE6ZWzwrMxk1Fjlk
> ZA%2FEPGmhQSHuPB2c%3D&amp;reserved=0
> >
> Thank you for the link. The Designware PCIE EP is implemented as a DMA
> engine driver so it's convenient to use the DMA engine API, whereas
> the R-Car PCIe-EP is implemented as an actual PCIe EP [0].

My means, needn't add new interface pci_epf_internal_dmac_xfr at epc/epf.
Your R-Car PCI-EP DMA part can implement as a dma engine driver like designware.

So EP functional driver use the same method to operate DMA regardless
EP controller type. 

Best regards
Frank Li 

> 
> [0]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kerne
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> next.git%2Ftree%2FDocumentation%2Fdevicetree%2Fbindings%2Fpci%2Frcar-pci-
> ep.yaml%3Fh%3Dnext-
> 20220302&amp;data=04%7C01%7Cfrank.li%40nxp.com%7C0e2e5fe8fd224076afb208d9fc
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> 2Sw%3D&amp;reserved=0
> 
> Cheers,
> Prabhakar
> 
> 
> > Best regards
> > Frank Li
> >
> > >
> > > Caution: EXT Email
> > >
> > > Hi,
> > >
> > > On Thu, Feb 10, 2022 at 8:40 AM Manivannan Sadhasivam
> > > <manivannan.sadhasivam@linaro.org> wrote:
> > > >
> > > > Hi,
> > > >
> > > > On Wed, Jan 26, 2022 at 07:50:38PM +0000, Lad Prabhakar wrote:
> > > > > Hi All,
> > > > >
> > > > > The current PCIe EPF framework supports DMA data transfers using
> > > external
> > > > > DMA only, this patch series aims to add support for platforms
> > > supporting
> > > > > internal DMAC on PCIe for data transfers.
> > > > >
> > > > > R-Car PCIe supports internal DMAC to transfer data between Internal
> Bus
> > > to
> > > > > PCI Express and vice versa. Last patch fills up the required flags
> and
> > > ops
> > > > > to support internal DMAC.
> > > > >
> > > > > Patches 1-3 are for PCIe EPF core to support internal DMAC handling,
> > > patch
> > > > > 4/5 is to fix test cases based on the conversation [1].
> > > > >
> > > >
> > > > This looks similar to the Synopsys eDMA IP [1] that goes with the
> > > Synopsys PCIe
> > > > endpoint IP. Why can't you represent it as a dmaengine driver and use
> the
> > > > existing DMA support?
> > > >
> > > Let me have a look. Could you please share a link to the Synopsys PCIe
> > > endpoint HW manual (the driver doesn't have a binding doc).
> > >
> > > Cheers,
> > > Prabhakar
> > >
> > > > [1]
> > >
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> reserved=0
> > >
> l.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Ftree%2Fdr
> > > ivers%2Fdma%2Fdw-
> > >
> edma&amp;data=04%7C01%7Cfrank.li%40nxp.com%7C95a5831aac544de2211508d9ec772f
> > >
> 9a%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637800819106821404%7CUnknow
> > >
> n%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI
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> 6Mn0%3D%7C3000&amp;sdata=yG39L2YBN9blGxTcXyVQwIXol8%2FCo%2FZ3GbGPIlqz6Mg%3D
> > > &amp;reserved=0
> > > >
> > > > > Patches are based on top of [1] next branch.
> > > > >
> > > > > [0]
> > >
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> %2F&amp;data=04%7C01%7Cfrank.li%40nxp.com%7C0e2e5fe8fd224076afb208d9fc70aa1
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> p;reserved=0
> > > cs.net%2Flists%2Flinux-
> > >
> pci%2Fmsg92385.html&amp;data=04%7C01%7Cfrank.li%40nxp.com%7C95a5831aac544de
> > >
> 2211508d9ec772f9a%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637800819106
> > >
> 821404%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6
> > >
> Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=ieX2gSSHFDumc1k2iWoOfMyHg236aJTE7UZ
> > > 5D74D9KM%3D&amp;reserved=0
> > > > > [1]
> > >
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> reserved=0
> > >
> l.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fhelgaas%2Fpci.git&amp;data=04%7C
> > >
> 01%7Cfrank.li%40nxp.com%7C95a5831aac544de2211508d9ec772f9a%7C686ea1d3bc2b4c
> > >
> 6fa92cd99c5c301635%7C0%7C0%7C637800819106821404%7CUnknown%7CTWFpbGZsb3d8eyJ
> > >
> WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;
> > > sdata=Qc5cW6y5OrxprDjFQ1dNMZ4ZUc656I3FZqClaUMLx%2FM%3D&amp;reserved=0
> > > > >
> > > > > Cheers,
> > > > > Prabhakar
> > > > >
> > > > > Lad Prabhakar (5):
> > > > >   PCI: endpoint: Add ops and flag to support internal DMAC
> > > > >   PCI: endpoint: Add support to data transfer using internal dmac
> > > > >   misc: pci_endpoint_test: Add driver data for Renesas RZ/G2{EHMN}
> > > > >   misc: pci_endpoint_test: Add support to pass flags for buffer
> > > > >     allocation
> > > > >   PCI: rcar-ep: Add support for DMAC
> > > > >
> > > > >  drivers/misc/pci_endpoint_test.c              |  56 ++++-
> > > > >  drivers/pci/controller/pcie-rcar-ep.c         | 227
> ++++++++++++++++++
> > > > >  drivers/pci/controller/pcie-rcar.h            |  23 ++
> > > > >  drivers/pci/endpoint/functions/pci-epf-test.c | 184 ++++++++++----
> > > > >  drivers/pci/endpoint/pci-epf-core.c           |  32 +++
> > > > >  include/linux/pci-epc.h                       |   8 +
> > > > >  include/linux/pci-epf.h                       |   7 +
> > > > >  7 files changed, 483 insertions(+), 54 deletions(-)
> > > > >
> > > > > --
> > > > > 2.25.1
> > > > >