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From:   Andrey Smirnov <andrew.smirnov@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     Andrey Smirnov <andrew.smirnov@gmail.com>, bhelgaas@google.com,
        Fabio Estevam <fabio.estevam@nxp.com>, cphealy@gmail.com,
        l.stach@pengutronix.de, Leonard Crestez <leonard.crestez@nxp.com>,
        "A.s. Dong" <aisheng.dong@nxp.com>,
        Richard Zhu <hongxing.zhu@nxp.com>, linux-imx@nxp.com,
        linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org
Subject: [PATCH 3/3] PCI: imx: Add support for i.MX8MQ
Date:   Sat, 17 Nov 2018 10:12:25 -0800
Message-Id: <20181117181225.10737-4-andrew.smirnov@gmail.com>
In-Reply-To: <20181117181225.10737-1-andrew.smirnov@gmail.com>
References: <20181117181225.10737-1-andrew.smirnov@gmail.com>
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Cc: bhelgaas@google.com
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: cphealy@gmail.com
Cc: 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>
Cc: linux-imx@nxp.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 drivers/pci/controller/dwc/Kconfig    |   2 +-
 drivers/pci/controller/dwc/pci-imx6.c | 117 ++++++++++++++++++++++++--
 2 files changed, 113 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index 91b0194240a5..2b139acccf32 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -90,7 +90,7 @@ config PCI_EXYNOS
 
 config PCI_IMX6
 	bool "Freescale i.MX6 PCIe controller"
-	depends on SOC_IMX6Q || (ARM && COMPILE_TEST)
+	depends on SOC_IMX8MQ || SOC_IMX6Q || (ARM && COMPILE_TEST)
 	depends on PCI_MSI_IRQ_DOMAIN
 	select PCIE_DW_HOST
 
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 3c3002861d25..8d1f310e41a6 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/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>
@@ -30,6 +31,14 @@
 
 #include "pcie-designware.h"
 
+#define IMX8MQ_PCIE_LINK_CAP_REG_OFFSET		0x7C
+#define IMX8MQ_PCIE_LINK_CAP_L1EL_64US		(0x6 << 15)
+
+#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 to_imx6_pcie(x)	dev_get_drvdata((x)->dev)
 
 enum imx6_pcie_variants {
@@ -37,6 +46,7 @@ enum imx6_pcie_variants {
 	IMX6SX,
 	IMX6QP,
 	IMX7D,
+	IMX8MQ,
 };
 
 struct imx6_pcie {
@@ -48,8 +58,10 @@ struct imx6_pcie {
 	struct clk		*pcie_inbound_axi;
 	struct clk		*pcie;
 	struct regmap		*iomuxc_gpr;
+	u32			gpr1x;
 	struct reset_control	*pciephy_reset;
 	struct reset_control	*apps_reset;
+	struct reset_control	*apps_clk_req;
 	struct reset_control	*turnoff_reset;
 	enum imx6_pcie_variants variant;
 	u32			tx_deemph_gen1;
@@ -59,6 +71,7 @@ struct imx6_pcie {
 	u32			tx_swing_low;
 	int			link_gen;
 	struct regulator	*vpcie;
+	u32			device_type[2];
 };
 
 /* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
@@ -245,7 +258,8 @@ static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie)
 {
 	u32 tmp;
 
-	if (imx6_pcie->variant == IMX7D)
+	if (imx6_pcie->variant == IMX7D ||
+	    imx6_pcie->variant == IMX8MQ)
 		return;
 
 	pcie_phy_read(imx6_pcie, PHY_RX_OVRD_IN_LO, &tmp);
@@ -261,6 +275,7 @@ 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)
@@ -294,6 +309,7 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
 
 	return 1;
 }
+#endif
 
 static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 {
@@ -301,6 +317,7 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 
 	switch (imx6_pcie->variant) {
 	case IMX7D:
+	case IMX8MQ: /* FALLTHROUGH */
 		reset_control_assert(imx6_pcie->pciephy_reset);
 		reset_control_assert(imx6_pcie->apps_reset);
 		break;
@@ -369,6 +386,18 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 		break;
 	case IMX7D:
 		break;
+	case IMX8MQ:
+		/*
+		 * Set the over ride low and enabled
+		 * make sure that REF_CLK is turned on.
+		 */
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE,
+				   0);
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
+		break;
 	}
 
 	return ret;
@@ -397,6 +426,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 {
 	struct dw_pcie *pci = imx6_pcie->pci;
 	struct device *dev = pci->dev;
+	unsigned int val;
 	int ret;
 
 	if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
@@ -445,6 +475,29 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	}
 
 	switch (imx6_pcie->variant) {
+	case IMX8MQ:
+		reset_control_deassert(imx6_pcie->pciephy_reset);
+		udelay(100);
+		/*
+		 * Configure the CLK_REQ# high, let the L1SS
+		 * automatically controlled by HW.
+		 */
+		reset_control_assert(imx6_pcie->apps_clk_req);
+
+		/*
+		 * Configure the L1 latency of rc to less than 64us
+		 * Otherwise, the L1/L1SUB wouldn't be enable by ASPM.
+		 */
+		val = dw_pcie_readl_dbi(imx6_pcie->pci,
+					SZ_1M +
+					IMX8MQ_PCIE_LINK_CAP_REG_OFFSET);
+		val &= ~PCI_EXP_LNKCAP_L1EL;
+		val |= IMX8MQ_PCIE_LINK_CAP_L1EL_64US;
+		dw_pcie_writel_dbi(imx6_pcie->pci,
+				   SZ_1M +
+				   IMX8MQ_PCIE_LINK_CAP_REG_OFFSET,
+				   val);
+		break;
 	case IMX7D:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
 		imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie);
@@ -483,6 +536,15 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 {
 	switch (imx6_pcie->variant) {
+	case IMX8MQ:
+		/*
+		 * TODO: Currently this code assumes external
+		 * oscillator is being used
+		 */
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
+				   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);
@@ -519,7 +581,8 @@ static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 	}
 
 	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
-			IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
+			   imx6_pcie->device_type[0],
+			   imx6_pcie->device_type[1]);
 }
 
 static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie)
@@ -528,7 +591,8 @@ static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie)
 	int mult, div;
 	u32 val;
 
-	if (imx6_pcie->variant == IMX7D)
+	if (imx6_pcie->variant == IMX7D ||
+	    imx6_pcie->variant == IMX8MQ)
 		return 0;
 
 	switch (phy_rate) {
@@ -616,6 +680,7 @@ static void imx6_pcie_ltssm_enable(struct device *dev)
 				   IMX6Q_GPR12_PCIE_CTL_2);
 		break;
 	case IMX7D:
+	case IMX8MQ:		/* FALLTHROUGH */
 		reset_control_deassert(imx6_pcie->apps_reset);
 		break;
 	}
@@ -798,10 +863,24 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
 	clk_disable_unprepare(imx6_pcie->pcie_phy);
 	clk_disable_unprepare(imx6_pcie->pcie_bus);
 
-	if (imx6_pcie->variant == IMX7D) {
+	switch (imx6_pcie->variant) {
+	case IMX7D:
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
+		break;
+	/*
+	 * Disable the override. Configure the CLK_REQ# high, let the
+	 * L1SS automatically controlled by HW when link is up.
+	 * Otherwise, turn off the REF_CLK to save power consumption.
+	 */
+	case IMX8MQ:
+		regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x,
+				   IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
+				   0);
+		break;
+	default:
+		break;
 	}
 }
 
@@ -870,6 +949,10 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 	imx6_pcie->variant =
 		(enum imx6_pcie_variants)of_device_get_match_data(dev);
 
+	imx6_pcie->device_type[0] = IMX6Q_GPR12_DEVICE_TYPE;
+	imx6_pcie->device_type[1] = FIELD_PREP(IMX6Q_GPR12_DEVICE_TYPE,
+					       PCI_EXP_TYPE_ROOT_PORT);
+
 	dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
 	if (IS_ERR(pci->dbi_base))
@@ -921,7 +1004,28 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 			return PTR_ERR(imx6_pcie->pcie_inbound_axi);
 		}
 		break;
-	case IMX7D:
+	case IMX8MQ:
+		if (of_property_read_u32(node, "fsl,iomux-gpr1x",
+					 &imx6_pcie->gpr1x)) {
+			dev_err(dev, "Failed to get GPR1x address\n");
+			return -EINVAL;
+		}
+
+		if (of_property_read_u32_array(
+			    node, "fsl,gpr12-device-type",
+			    imx6_pcie->device_type,
+			    ARRAY_SIZE(imx6_pcie->device_type))) {
+			dev_err(dev, "Failed to get device type mask/value\n");
+			return -EINVAL;
+		}
+
+		imx6_pcie->apps_clk_req =
+			devm_reset_control_get_exclusive(dev, "clkreq");
+		if (IS_ERR(imx6_pcie->apps_clk_req)) {
+			dev_err(dev, "Failed to get PCIE APPS CLK_REQ# reset control\n");
+			return PTR_ERR(imx6_pcie->apps_clk_req);
+		}
+	case IMX7D:		/* FALLTHROUGH */
 		imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev,
 									    "pciephy");
 		if (IS_ERR(imx6_pcie->pciephy_reset)) {
@@ -1011,6 +1115,7 @@ static const struct of_device_id imx6_pcie_of_match[] = {
 	{ .compatible = "fsl,imx6sx-pcie", .data = (void *)IMX6SX, },
 	{ .compatible = "fsl,imx6qp-pcie", .data = (void *)IMX6QP, },
 	{ .compatible = "fsl,imx7d-pcie",  .data = (void *)IMX7D,  },
+	{ .compatible = "fsl,imx8mq-pcie", .data = (void *)IMX8MQ, } ,
 	{},
 };
 
@@ -1027,6 +1132,7 @@ 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
@@ -1036,6 +1142,7 @@ 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);
 }
-- 
2.19.1