PCI: qcom-ep: Disable MHI RAM data parity error interrupt for SA8775P SoC

SA8775P SoC has support for the hardware parity check feature on the MHI
RAM (entity that holds MHI registers, etc.) But due to a hardware bug in
the parity check logic, the data parity error interrupt is getting
generated all the time when using MHI. So the hardware team has suggested
disabling the parity check error to work around the hardware bug.

Mask the parity error interrupt in PARF_INT_ALL_5_MASK register.

Fixes: 58d0d3e0 ("PCI: qcom-ep: Add support for SA8775P SOC")
Link: https://lore.kernel.org/linux-pci/20240808063057.7394-1-manivannan.sadhasivam@linaro.orgSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/controller/dwc/pcie-qcom-ep.c

@@ -58,6 +58,7 @@
 #define PARF_DEBUG_CNT_AUX_CLK_IN_L1SUB_L2	0xc88
 #define PARF_DEVICE_TYPE			0x1000
 #define PARF_BDF_TO_SID_CFG			0x2c00
+#define PARF_INT_ALL_5_MASK			0x2dcc
 
 /* PARF_INT_ALL_{STATUS/CLEAR/MASK} register fields */
 #define PARF_INT_ALL_LINK_DOWN			BIT(1)
@@ -127,6 +128,9 @@
 /* PARF_CFG_BITS register fields */
 #define PARF_CFG_BITS_REQ_EXIT_L1SS_MSI_LTR_EN	BIT(1)
 
+/* PARF_INT_ALL_5_MASK fields */
+#define PARF_INT_ALL_5_MHI_RAM_DATA_PARITY_ERR	BIT(0)
+
 /* ELBI registers */
 #define ELBI_SYS_STTS				0x08
 #define ELBI_CS2_ENABLE				0xa4
@@ -158,10 +162,12 @@ enum qcom_pcie_ep_link_status {
  * struct qcom_pcie_ep_cfg - Per SoC config struct
  * @hdma_support: HDMA support on this SoC
  * @override_no_snoop: Override NO_SNOOP attribute in TLP to enable cache snooping
+ * @disable_mhi_ram_parity_check: Disable MHI RAM data parity error check
  */
 struct qcom_pcie_ep_cfg {
 	bool hdma_support;
 	bool override_no_snoop;
+	bool disable_mhi_ram_parity_check;
 };
 
 /**
@@ -480,6 +486,12 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci)
 	      PARF_INT_ALL_LINK_UP | PARF_INT_ALL_EDMA;
 	writel_relaxed(val, pcie_ep->parf + PARF_INT_ALL_MASK);
 
+	if (pcie_ep->cfg && pcie_ep->cfg->disable_mhi_ram_parity_check) {
+		val = readl_relaxed(pcie_ep->parf + PARF_INT_ALL_5_MASK);
+		val &= ~PARF_INT_ALL_5_MHI_RAM_DATA_PARITY_ERR;
+		writel_relaxed(val, pcie_ep->parf + PARF_INT_ALL_5_MASK);
+	}
+
 	ret = dw_pcie_ep_init_registers(&pcie_ep->pci.ep);
 	if (ret) {
 		dev_err(dev, "Failed to complete initialization: %d\n", ret);
@@ -901,6 +913,7 @@ static void qcom_pcie_ep_remove(struct platform_device *pdev)
 static const struct qcom_pcie_ep_cfg cfg_1_34_0 = {
 	.hdma_support = true,
 	.override_no_snoop = true,
+	.disable_mhi_ram_parity_check = true,
 };
 
 static const struct of_device_id qcom_pcie_ep_match[] = {