PCI: imx6: Add PLL lock check for i.MX95 SoC

PLL lock is required to ensure that the PLL clock is stable before enabling
the controller in i.MX95 SoC.

Signed-off-by: Richard Zhu <[email protected]>
[mani: subject and description rewording]
Signed-off-by: Manivannan Sadhasivam <[email protected]>
Reviewed-by: Frank Li <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: Richard Zhu

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

@@ -45,6 +45,9 @@
 #define IMX95_PCIE_PHY_GEN_CTRL			0x0
 #define IMX95_PCIE_REF_USE_PAD			BIT(17)
 
+#define IMX95_PCIE_PHY_MPLLA_CTRL		0x10
+#define IMX95_PCIE_PHY_MPLL_STATE		BIT(30)
+
 #define IMX95_PCIE_SS_RW_REG_0			0xf0
 #define IMX95_PCIE_REF_CLKEN			BIT(23)
 #define IMX95_PCIE_PHY_CR_PARA_SEL		BIT(9)
@@ -132,6 +135,7 @@ struct imx_pcie_drvdata {
 	int (*init_phy)(struct imx_pcie *pcie);
 	int (*enable_ref_clk)(struct imx_pcie *pcie, bool enable);
 	int (*core_reset)(struct imx_pcie *pcie, bool assert);
+	int (*wait_pll_lock)(struct imx_pcie *pcie);
 	const struct dw_pcie_host_ops *ops;
 };
 
@@ -479,6 +483,23 @@ static void imx7d_pcie_wait_for_phy_pll_lock(struct imx_pcie *imx_pcie)
 		dev_err(dev, "PCIe PLL lock timeout\n");
 }
 
+static int imx95_pcie_wait_for_phy_pll_lock(struct imx_pcie *imx_pcie)
+{
+	u32 val;
+	struct device *dev = imx_pcie->pci->dev;
+
+	if (regmap_read_poll_timeout(imx_pcie->iomuxc_gpr,
+				     IMX95_PCIE_PHY_MPLLA_CTRL, val,
+				     val & IMX95_PCIE_PHY_MPLL_STATE,
+				     PHY_PLL_LOCK_WAIT_USLEEP_MAX,
+				     PHY_PLL_LOCK_WAIT_TIMEOUT)) {
+		dev_err(dev, "PCIe PLL lock timeout\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
 static int imx_setup_phy_mpll(struct imx_pcie *imx_pcie)
 {
 	unsigned long phy_rate = 0;
@@ -1225,6 +1246,12 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 		goto err_phy_off;
 	}
 
+	if (imx_pcie->drvdata->wait_pll_lock) {
+		ret = imx_pcie->drvdata->wait_pll_lock(imx_pcie);
+		if (ret < 0)
+			goto err_phy_off;
+	}
+
 	imx_setup_phy_mpll(imx_pcie);
 
 	return 0;
@@ -1826,6 +1853,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.mode_mask[0] = IMX95_PCIE_DEVICE_TYPE,
 		.core_reset = imx95_pcie_core_reset,
 		.init_phy = imx95_pcie_init_phy,
+		.wait_pll_lock = imx95_pcie_wait_for_phy_pll_lock,
 	},
 	[IMX8MQ_EP] = {
 		.variant = IMX8MQ_EP,
@@ -1880,6 +1908,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
 		.mode_mask[0] = IMX95_PCIE_DEVICE_TYPE,
 		.init_phy = imx95_pcie_init_phy,
 		.core_reset = imx95_pcie_core_reset,
+		.wait_pll_lock = imx95_pcie_wait_for_phy_pll_lock,
 		.epc_features = &imx95_pcie_epc_features,
 		.mode = DW_PCIE_EP_TYPE,
 	},