[PATCH v3 1/2] PCI: xilinx-nwl: Enable coherent PCIe DMA traffic using CCI
From: Bharat Kumar Gogada <hidden>
Date: 2021-02-22 08:49:04
Also in:
lkml
Subsystem:
pci native host bridge and endpoint drivers, pci subsystem, the rest · Maintainers:
Lorenzo Pieralisi, Krzysztof Wilczyński, Manivannan Sadhasivam, Bjorn Helgaas, Linus Torvalds
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 <redacted> --- 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