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Message-ID: <BYAPR02MB55599675DC55C6F7568B6FA6A5649@BYAPR02MB5559.namprd02.prod.outlook.com>
Date: Tue, 23 Mar 2021 11:17:48 +0000
From: Bharat Kumar Gogada <bharatku@...inx.com>
To: Bharat Kumar Gogada <bharatku@...inx.com>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
"lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>
Subject: RE: [PATCH v3 1/2] PCI: xilinx-nwl: Enable coherent PCIe DMA traffic
using CCI
Ping.
> -----Original Message-----
> From: Bharat Kumar Gogada
> Sent: Monday, March 15, 2021 11:43 AM
> To: Bharat Kumar Gogada <bharat.kumar.gogada@...inx.com>; linux-
> pci@...r.kernel.org; linux-kernel@...r.kernel.org
> Cc: bhelgaas@...gle.com
> Subject: RE: [PATCH v3 1/2] PCI: xilinx-nwl: Enable coherent PCIe DMA traffic
> using CCI
>
> Ping.
>
> > -----Original Message-----
> > From: Bharat Kumar Gogada <bharat.kumar.gogada@...inx.com>
> > Sent: Monday, February 22, 2021 2:18 PM
> > To: linux-pci@...r.kernel.org; linux-kernel@...r.kernel.org
> > Cc: bhelgaas@...gle.com; Bharat Kumar Gogada <bharatku@...inx.com>
> > Subject: [PATCH v3 1/2] PCI: xilinx-nwl: Enable coherent PCIe DMA
> > traffic using CCI
> >
> > Add support for routing PCIe DMA traffic coherently when Cache
> > Coherent Interconnect (CCI) is enabled in the system.
> > The "dma-coherent" property is used to determine if CCI is enabled or not.
> > Refer to https://developer.arm.com/documentation/ddi0470/k/preface
> > for the CCI specification.
> >
> > Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@...inx.com>
> > ---
> > drivers/pci/controller/pcie-xilinx-nwl.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c
> > b/drivers/pci/controller/pcie-xilinx-nwl.c
> > index 07e36661bbc2..8689311c5ef6 100644
> > --- a/drivers/pci/controller/pcie-xilinx-nwl.c
> > +++ b/drivers/pci/controller/pcie-xilinx-nwl.c
> > @@ -26,6 +26,7 @@
> >
> > /* Bridge core config registers */
> > #define BRCFG_PCIE_RX0 0x00000000
> > +#define BRCFG_PCIE_RX1 0x00000004
> > #define BRCFG_INTERRUPT 0x00000010
> > #define BRCFG_PCIE_RX_MSG_FILTER 0x00000020
> >
> > @@ -128,6 +129,7 @@
> > #define NWL_ECAM_VALUE_DEFAULT 12
> >
> > #define CFG_DMA_REG_BAR GENMASK(2, 0)
> > +#define CFG_PCIE_CACHE GENMASK(7, 0)
> >
> > #define INT_PCI_MSI_NR (2 * 32)
> >
> > @@ -675,6 +677,11 @@ static int nwl_pcie_bridge_init(struct nwl_pcie
> > *pcie)
> > nwl_bridge_writel(pcie, CFG_ENABLE_MSG_FILTER_MASK,
> > BRCFG_PCIE_RX_MSG_FILTER);
> >
> > + /* This routes the PCIe DMA traffic to go through CCI path */
> > + if (of_dma_is_coherent(dev->of_node))
> > + nwl_bridge_writel(pcie, nwl_bridge_readl(pcie,
> > BRCFG_PCIE_RX1) |
> > + CFG_PCIE_CACHE, BRCFG_PCIE_RX1);
> > +
> > err = nwl_wait_for_link(pcie);
> > if (err)
> > return err;
> > --
> > 2.17.1
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