Ping. > -----Original Message----- > From: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxxxxx> > Sent: Monday, February 22, 2021 2:18 PM > To: linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Cc: bhelgaas@xxxxxxxxxx; Bharat Kumar Gogada <bharatku@xxxxxxxxxx> > 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@xxxxxxxxxx> > --- > 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
