PCI: imx6: Add iMX95 Endpoint (EP) support

Add iMX95 EP support and add 64bit address support.
The internal bus bridge for PCI support 64bit DMA address in iMX95 hence
call dma_set_mask_and_coherent() to set 64 bit DMA mask.

Link: https://lore.kernel.org/r/20240220161924.3871774-15-Frank.Li@nxp.com
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Author: nxpfrankli

drivers/pci/controller/dwc/pci-imx6.c

@@ -69,6 +69,7 @@ enum imx6_pcie_variants {
 	IMX8MQ_EP,
 	IMX8MM_EP,
 	IMX8MP_EP,
+	IMX95_EP,
 };
 
 #define IMX6_PCIE_FLAG_IMX6_PHY			BIT(0)
@@ -78,6 +79,7 @@ enum imx6_pcie_variants {
 #define IMX6_PCIE_FLAG_HAS_APP_RESET		BIT(4)
 #define IMX6_PCIE_FLAG_HAS_PHY_RESET		BIT(5)
 #define IMX6_PCIE_FLAG_HAS_SERDES		BIT(6)
+#define IMX6_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
 
 #define imx6_check_flag(pci, val)     (pci->drvdata->flags & val)
 
@@ -610,6 +612,7 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 		break;
 	case IMX7D:
 	case IMX95:
+	case IMX95_EP:
 		break;
 	case IMX8MM:
 	case IMX8MM_EP:
@@ -1044,6 +1047,23 @@ static const struct pci_epc_features imx8m_pcie_epc_features = {
 	.align = SZ_64K,
 };
 
+/*
+ * BAR#	| Default BAR enable	| Default BAR Type	| Default BAR Size	| BAR Sizing Scheme
+ * ================================================================================================
+ * BAR0	| Enable		| 64-bit		| 1 MB			| Programmable Size
+ * BAR1	| Disable		| 32-bit		| 64 KB			| Fixed Size
+ *        BAR1 should be disabled if BAR0 is 64bit.
+ * BAR2	| Enable		| 32-bit		| 1 MB			| Programmable Size
+ * BAR3	| Enable		| 32-bit		| 64 KB			| Programmable Size
+ * BAR4	| Enable		| 32-bit		| 1M			| Programmable Size
+ * BAR5	| Enable		| 32-bit		| 64 KB			| Programmable Size
+ */
+static const struct pci_epc_features imx95_pcie_epc_features = {
+	.msi_capable = true,
+	.bar[BAR_1] = { .type = BAR_FIXED, .fixed_size = SZ_64K, },
+	.align = SZ_4K,
+};
+
 static const struct pci_epc_features*
 imx6_pcie_ep_get_features(struct dw_pcie_ep *ep)
 {
@@ -1086,6 +1106,18 @@ static int imx6_add_pcie_ep(struct imx6_pcie *imx6_pcie,
 
 	pci->dbi_base2 = pci->dbi_base + pcie_dbi2_offset;
 
+	/*
+	 * FIXME: Ideally, dbi2 base address should come from DT. But since only IMX95 is defining
+	 * "dbi2" in DT, "dbi_base2" is set to NULL here for that platform alone so that the DWC
+	 * core code can fetch that from DT. But once all platform DTs were fixed, this and the
+	 * above "dbi_base2" setting should be removed.
+	 */
+	if (device_property_match_string(dev, "reg-names", "dbi2") >= 0)
+		pci->dbi_base2 = NULL;
+
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_SUPPORT_64BIT))
+		dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
+
 	ret = dw_pcie_ep_init(ep);
 	if (ret) {
 		dev_err(dev, "failed to initialize endpoint\n");
@@ -1556,6 +1588,20 @@ static const struct imx6_pcie_drvdata drvdata[] = {
 		.mode_mask[0] = IMX6Q_GPR12_DEVICE_TYPE,
 		.epc_features = &imx8m_pcie_epc_features,
 	},
+	[IMX95_EP] = {
+		.variant = IMX95_EP,
+		.flags = IMX6_PCIE_FLAG_HAS_SERDES |
+			 IMX6_PCIE_FLAG_SUPPORT_64BIT,
+		.clk_names = imx8mq_clks,
+		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
+		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
+		.ltssm_mask = IMX95_PCIE_LTSSM_EN,
+		.mode_off[0]  = IMX95_PE0_GEN_CTRL_1,
+		.mode_mask[0] = IMX95_PCIE_DEVICE_TYPE,
+		.init_phy = imx95_pcie_init_phy,
+		.epc_features = &imx95_pcie_epc_features,
+		.mode = DW_PCIE_EP_TYPE,
+	},
 };
 
 static const struct of_device_id imx6_pcie_of_match[] = {
@@ -1570,6 +1616,7 @@ static const struct of_device_id imx6_pcie_of_match[] = {
 	{ .compatible = "fsl,imx8mq-pcie-ep", .data = &drvdata[IMX8MQ_EP], },
 	{ .compatible = "fsl,imx8mm-pcie-ep", .data = &drvdata[IMX8MM_EP], },
 	{ .compatible = "fsl,imx8mp-pcie-ep", .data = &drvdata[IMX8MP_EP], },
+	{ .compatible = "fsl,imx95-pcie-ep", .data = &drvdata[IMX95_EP], },
 	{},
 };