PCI: dwc: Add support to enable CDM register check

Add support to enable CDM (Configuration Dependent Module) register
check for any data corruption based on the DT property
'snps,enable-cdm-check'.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

drivers/pci/controller/dwc/pcie-designware.c

@@ -547,4 +547,11 @@ void dw_pcie_setup(struct dw_pcie *pci)
 		break;
 	}
 	dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
+
+	if (of_property_read_bool(np, "snps,enable-cdm-check")) {
+		val = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS);
+		val |= PCIE_PL_CHK_REG_CHK_REG_CONTINUOUS |
+		       PCIE_PL_CHK_REG_CHK_REG_START;
+		dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, val);
+	}
 }

drivers/pci/controller/dwc/pcie-designware.h

@@ -86,6 +86,15 @@
 #define PCIE_MISC_CONTROL_1_OFF		0x8BC
 #define PCIE_DBI_RO_WR_EN		BIT(0)
 
+#define PCIE_PL_CHK_REG_CONTROL_STATUS			0xB20
+#define PCIE_PL_CHK_REG_CHK_REG_START			BIT(0)
+#define PCIE_PL_CHK_REG_CHK_REG_CONTINUOUS		BIT(1)
+#define PCIE_PL_CHK_REG_CHK_REG_COMPARISON_ERROR	BIT(16)
+#define PCIE_PL_CHK_REG_CHK_REG_LOGIC_ERROR		BIT(17)
+#define PCIE_PL_CHK_REG_CHK_REG_COMPLETE		BIT(18)
+
+#define PCIE_PL_CHK_REG_ERR_ADDR			0xB28
+
 /*
  * iATU Unroll-specific register definitions
  * From 4.80 core version the address translation will be made by unroll