On Thu, Feb 10, 2022 at 11:05:45AM +0000, Lad, Prabhakar wrote: > On Thu, Feb 10, 2022 at 10:50 AM Manivannan Sadhasivam > <manivannan.sadhasivam@xxxxxxxxxx> wrote: > > > > On Thu, Feb 10, 2022 at 09:24:19AM +0000, Lad, Prabhakar wrote: > > > Hi, > > > > > > On Thu, Feb 10, 2022 at 8:40 AM Manivannan Sadhasivam > > > <manivannan.sadhasivam@xxxxxxxxxx> 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). > > > > > > > I don't think the PCIe reference manual is available publicly. And you are right > > that the driver is not tied to devicetree. The reason is, it gets probed using > > the PCI ID of the EP and all the resources are defined statically in the driver > > itself. > > > In R-Car PCIe the internal dmac is part of the PCIe block itself [0] > and not a separate block. I don't see any drivers implementing the > internal dmac drivers as a DMA engine driver. For example the Renesas > SDHI driver has internal dmac too, this is handled in the SDHI driver > itself [1] and not implemented as DMA engine driver. Let me know if my > understanding is wrong here. > Okay, thanks for the clarification. I thought that if the IP is same, we could implement it as a standalone DMA engine driver, but looks like it is customized. So I guess it is reasonable to have an internal implementation. Thanks, Mani > [0] https://elixir.bootlin.com/linux/v5.17-rc3/source/Documentation/devicetree/bindings/pci/rcar-pci-ep.yaml#L76 > [1] https://elixir.bootlin.com/linux/v5.17-rc3/source/drivers/mmc/host/renesas_sdhi_internal_dmac.c > > Cheers, > Prabhakar > > > Thanks, > > Mani > > > > > Cheers, > > > Prabhakar > > > > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/dma/dw-edma > > > > > > > > > Patches are based on top of [1] next branch. > > > > > > > > > > [0] https://www.spinics.net/lists/linux-pci/msg92385.html > > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git > > > > > > > > > > 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 > > > > >
