PCI: imx6: Add support for i.MX8MQ

Add code needed to support i.MX8MQ variant.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Leonard Crestez <leonard.crestez@nxp.com>
Cc: "A.s. Dong" <aisheng.dong@nxp.com>
Cc: Richard Zhu <hongxing.zhu@nxp.com>

Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt

@@ -9,6 +9,7 @@ Required properties:
 	- "fsl,imx6sx-pcie",
 	- "fsl,imx6qp-pcie"
 	- "fsl,imx7d-pcie"
+	- "fsl,imx8mq-pcie"
 - reg: base address and length of the PCIe controller
 - interrupts: A list of interrupt outputs of the controller. Must contain an
   entry for each entry in the interrupt-names property.
@@ -45,7 +46,7 @@ Additional required properties for imx6sx-pcie:
   PCIE_PHY power domains
 - power-domain-names: Must be "pcie", "pcie_phy"
 
-Additional required properties for imx7d-pcie:
+Additional required properties for imx7d-pcie and imx8mq-pcie:
 - power-domains: Must be set to a phandle pointing to PCIE_PHY power domain
 - resets: Must contain phandles to PCIe-related reset lines exposed by SRC
   IP block

drivers/pci/controller/dwc/Kconfig

@@ -89,8 +89,8 @@ config PCI_EXYNOS
 	select PCIE_DW_HOST
 
 config PCI_IMX6
-	bool "Freescale i.MX6/7 PCIe controller"
-	depends on SOC_IMX6Q || SOC_IMX7D || (ARM && COMPILE_TEST)
+	bool "Freescale i.MX6/7/8 PCIe controller"
+	depends on SOC_IMX6Q || SOC_IMX7D || (ARM64 && ARCH_MXC) || COMPILE_TEST
 	depends on PCI_MSI_IRQ_DOMAIN
 	select PCIE_DW_HOST
 

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

@@ -8,6 +8,7 @@
  * Author: Sean Cross <xobs@kosagi.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio.h>
@@ -32,6 +33,12 @@
 
 #include "pcie-designware.h"
 
+#define IMX8MQ_GPR_PCIE_REF_USE_PAD		BIT(9)
+#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN	BIT(10)
+#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE	BIT(11)
+#define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE	GENMASK(11, 8)
+#define IMX8MQ_PCIE2_BASE_ADDR			0x33c00000
+
 #define to_imx6_pcie(x)	dev_get_drvdata((x)->dev)
 
 enum imx6_pcie_variants {
@@ -39,6 +46,7 @@ enum imx6_pcie_variants {
 	IMX6SX,
 	IMX6QP,
 	IMX7D,
+	IMX8MQ,
 };
 
 #define IMX6_PCIE_FLAG_IMX6_PHY			BIT(0)
@@ -58,6 +66,7 @@ struct imx6_pcie {
 	struct clk		*pcie_inbound_axi;
 	struct clk		*pcie;
 	struct regmap		*iomuxc_gpr;
+	u32			controller_id;
 	struct reset_control	*pciephy_reset;
 	struct reset_control	*apps_reset;
 	struct reset_control	*turnoff_reset;
@@ -275,6 +284,7 @@ static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie)
 	pcie_phy_write(imx6_pcie, PHY_RX_OVRD_IN_LO, tmp);
 }
 
+#ifdef CONFIG_ARM
 /*  Added for PCI abort handling */
 static int imx6q_pcie_abort_handler(unsigned long addr,
 		unsigned int fsr, struct pt_regs *regs)
@@ -308,6 +318,7 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
 
 	return 1;
 }
+#endif
 
 static int imx6_pcie_attach_pd(struct device *dev)
 {
@@ -352,6 +363,7 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 
 	switch (imx6_pcie->drvdata->variant) {
 	case IMX7D:
+	case IMX8MQ:
 		reset_control_assert(imx6_pcie->pciephy_reset);
 		reset_control_assert(imx6_pcie->apps_reset);
 		break;
@@ -386,10 +398,17 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 }
 
+static unsigned int imx6_pcie_grp_offset(const struct imx6_pcie *imx6_pcie)
+{
+	WARN_ON(imx6_pcie->drvdata->variant != IMX8MQ);
+	return imx6_pcie->controller_id == 1 ? IOMUXC_GPR16 : IOMUXC_GPR14;
+}
+
 static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
 	struct device *dev = pci->dev;
+	unsigned int offset;
 	int ret = 0;
 
 	switch (imx6_pcie->drvdata->variant) {
@@ -420,6 +439,19 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 		break;
 	case IMX7D:
 		break;
+	case IMX8MQ:
+		offset = imx6_pcie_grp_offset(imx6_pcie);
+		/*
+		 * Set the over ride low and enabled
+		 * make sure that REF_CLK is turned on.
+		 */
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, offset,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE,
+				   0);
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, offset,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
+		break;
 	}
 
 	return ret;
@@ -496,6 +528,9 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 
 	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MQ:
+		reset_control_deassert(imx6_pcie->pciephy_reset);
+		break;
 	case IMX7D:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
 		imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie);
@@ -531,9 +566,37 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 }
 
+static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
+{
+	unsigned int mask, val;
+
+	if (imx6_pcie->drvdata->variant == IMX8MQ &&
+	    imx6_pcie->controller_id == 1) {
+		mask   = IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE;
+		val    = FIELD_PREP(IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE,
+				    PCI_EXP_TYPE_ROOT_PORT);
+	} else {
+		mask = IMX6Q_GPR12_DEVICE_TYPE;
+		val  = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE,
+				  PCI_EXP_TYPE_ROOT_PORT);
+	}
+
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, mask, val);
+}
+
 static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 {
 	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MQ:
+		/*
+		 * TODO: Currently this code assumes external
+		 * oscillator is being used
+		 */
+		regmap_update_bits(imx6_pcie->iomuxc_gpr,
+				   imx6_pcie_grp_offset(imx6_pcie),
+				   IMX8MQ_GPR_PCIE_REF_USE_PAD,
+				   IMX8MQ_GPR_PCIE_REF_USE_PAD);
+		break;
 	case IMX7D:
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0);
@@ -569,8 +632,7 @@ static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 		break;
 	}
 
-	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
-			IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
+	imx6_pcie_configure_type(imx6_pcie);
 }
 
 static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie)
@@ -667,6 +729,7 @@ static void imx6_pcie_ltssm_enable(struct device *dev)
 				   IMX6Q_GPR12_PCIE_CTL_2);
 		break;
 	case IMX7D:
+	case IMX8MQ:
 		reset_control_deassert(imx6_pcie->apps_reset);
 		break;
 	}
@@ -1002,6 +1065,10 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 		}
 		break;
 	case IMX7D:
+	case IMX8MQ:
+		if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
+			imx6_pcie->controller_id = 1;
+
 		imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev,
 									    "pciephy");
 		if (IS_ERR(imx6_pcie->pciephy_reset)) {
@@ -1117,6 +1184,9 @@ static const struct imx6_pcie_drvdata drvdata[] = {
 	[IMX7D] = {
 		.variant = IMX7D,
 	},
+	[IMX8MQ] = {
+		.variant = IMX8MQ,
+	},
 };
 
 static const struct of_device_id imx6_pcie_of_match[] = {
@@ -1124,6 +1194,7 @@ static const struct of_device_id imx6_pcie_of_match[] = {
 	{ .compatible = "fsl,imx6sx-pcie", .data = &drvdata[IMX6SX], },
 	{ .compatible = "fsl,imx6qp-pcie", .data = &drvdata[IMX6QP], },
 	{ .compatible = "fsl,imx7d-pcie",  .data = &drvdata[IMX7D],  },
+	{ .compatible = "fsl,imx8mq-pcie", .data = &drvdata[IMX8MQ], } ,
 	{},
 };
 
@@ -1140,6 +1211,7 @@ static struct platform_driver imx6_pcie_driver = {
 
 static int __init imx6_pcie_init(void)
 {
+#ifdef CONFIG_ARM
 	/*
 	 * Since probe() can be deferred we need to make sure that
 	 * hook_fault_code is not called after __init memory is freed
@@ -1149,6 +1221,7 @@ static int __init imx6_pcie_init(void)
 	 */
 	hook_fault_code(8, imx6q_pcie_abort_handler, SIGBUS, 0,
 			"external abort on non-linefetch");
+#endif
 
 	return platform_driver_register(&imx6_pcie_driver);
 }