PCI: imx6: Add support for i.MX6 PCIe controller

Add support for the PCIe port present on the i.MX6 family of controllers.
These use the Synopsis Designware core tied to their own PHY.

Signed-off-by: Sean Cross <xobs@kosagi.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 582 insertions, 0 deletions

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 3d95048..efa24d9 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -15,6 +15,12 @@ config PCI_EXYNOS
 	select PCIEPORTBUS
 	select PCIE_DW
 
+config PCI_IMX6
+	bool "Freescale i.MX6 PCIe controller"
+	depends on SOC_IMX6Q
+	select PCIEPORTBUS
+	select PCIE_DW
+
 config PCI_TEGRA
 	bool "NVIDIA Tegra PCIe controller"
 	depends on ARCH_TEGRA
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index c9a997b..287d6a0 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_PCIE_DW) += pcie-designware.o
 obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o
+obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
 obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
 obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
new file mode 100644
index 0000000..5afa922
--- /dev/null
+++ b/drivers/pci/host/pci-imx6.c
@@ -0,0 +1,575 @@
+/*
+ * PCIe host controller driver for Freescale i.MX6 SoCs
+ *
+ * Copyright (C) 2013 Kosagi
+ *		http://www.kosagi.com
+ *
+ * Author: Sean Cross <xobs@kosagi.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/resource.h>
+#include <linux/signal.h>
+#include <linux/types.h>
+
+#include "pcie-designware.h"
+
+#define to_imx6_pcie(x)	container_of(x, struct imx6_pcie, pp)
+
+struct imx6_pcie {
+	int			reset_gpio;
+	int			power_on_gpio;
+	int			wake_up_gpio;
+	int			disable_gpio;
+	struct clk		*lvds_gate;
+	struct clk		*sata_ref_100m;
+	struct clk		*pcie_ref_125m;
+	struct clk		*pcie_axi;
+	struct pcie_port	pp;
+	struct regmap		*iomuxc_gpr;
+	void __iomem		*mem_base;
+};
+
+/* PCIe Port Logic registers (memory-mapped) */
+#define PL_OFFSET 0x700
+#define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
+#define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
+
+#define PCIE_PHY_CTRL (PL_OFFSET + 0x114)
+#define PCIE_PHY_CTRL_DATA_LOC 0
+#define PCIE_PHY_CTRL_CAP_ADR_LOC 16
+#define PCIE_PHY_CTRL_CAP_DAT_LOC 17
+#define PCIE_PHY_CTRL_WR_LOC 18
+#define PCIE_PHY_CTRL_RD_LOC 19
+
+#define PCIE_PHY_STAT (PL_OFFSET + 0x110)
+#define PCIE_PHY_STAT_ACK_LOC 16
+
+/* PHY registers (not memory-mapped) */
+#define PCIE_PHY_RX_ASIC_OUT 0x100D
+
+#define PHY_RX_OVRD_IN_LO 0x1005
+#define PHY_RX_OVRD_IN_LO_RX_DATA_EN (1 << 5)
+#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1 << 3)
+
+static int pcie_phy_poll_ack(void __iomem *dbi_base, int exp_val)
+{
+	u32 val;
+	u32 max_iterations = 10;
+	u32 wait_counter = 0;
+
+	do {
+		val = readl(dbi_base + PCIE_PHY_STAT);
+		val = (val >> PCIE_PHY_STAT_ACK_LOC) & 0x1;
+		wait_counter++;
+
+		if (val == exp_val)
+			return 0;
+
+		udelay(1);
+	} while (wait_counter < max_iterations);
+
+	return -ETIMEDOUT;
+}
+
+static int pcie_phy_wait_ack(void __iomem *dbi_base, int addr)
+{
+	u32 val;
+	int ret;
+
+	val = addr << PCIE_PHY_CTRL_DATA_LOC;
+	writel(val, dbi_base + PCIE_PHY_CTRL);
+
+	val |= (0x1 << PCIE_PHY_CTRL_CAP_ADR_LOC);
+	writel(val, dbi_base + PCIE_PHY_CTRL);
+
+	ret = pcie_phy_poll_ack(dbi_base, 1);
+	if (ret)
+		return ret;
+
+	val = addr << PCIE_PHY_CTRL_DATA_LOC;
+	writel(val, dbi_base + PCIE_PHY_CTRL);
+
+	ret = pcie_phy_poll_ack(dbi_base, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/* Read from the 16-bit PCIe PHY control registers (not memory-mapped) */
+static int pcie_phy_read(void __iomem *dbi_base, int addr , int *data)
+{
+	u32 val, phy_ctl;
+	int ret;
+
+	ret = pcie_phy_wait_ack(dbi_base, addr);
+	if (ret)
+		return ret;
+
+	/* assert Read signal */
+	phy_ctl = 0x1 << PCIE_PHY_CTRL_RD_LOC;
+	writel(phy_ctl, dbi_base + PCIE_PHY_CTRL);
+
+	ret = pcie_phy_poll_ack(dbi_base, 1);
+	if (ret)
+		return ret;
+
+	val = readl(dbi_base + PCIE_PHY_STAT);
+	*data = val & 0xffff;
+
+	/* deassert Read signal */
+	writel(0x00, dbi_base + PCIE_PHY_CTRL);
+
+	ret = pcie_phy_poll_ack(dbi_base, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int pcie_phy_write(void __iomem *dbi_base, int addr, int data)
+{
+	u32 var;
+	int ret;
+
+	/* write addr */
+	/* cap addr */
+	ret = pcie_phy_wait_ack(dbi_base, addr);
+	if (ret)
+		return ret;
+
+	var = data << PCIE_PHY_CTRL_DATA_LOC;
+	writel(var, dbi_base + PCIE_PHY_CTRL);
+
+	/* capture data */
+	var |= (0x1 << PCIE_PHY_CTRL_CAP_DAT_LOC);
+	writel(var, dbi_base + PCIE_PHY_CTRL);
+
+	ret = pcie_phy_poll_ack(dbi_base, 1);
+	if (ret)
+		return ret;
+
+	/* deassert cap data */
+	var = data << PCIE_PHY_CTRL_DATA_LOC;
+	writel(var, dbi_base + PCIE_PHY_CTRL);
+
+	/* wait for ack de-assertion */
+	ret = pcie_phy_poll_ack(dbi_base, 0);
+	if (ret)
+		return ret;
+
+	/* assert wr signal */
+	var = 0x1 << PCIE_PHY_CTRL_WR_LOC;
+	writel(var, dbi_base + PCIE_PHY_CTRL);
+
+	/* wait for ack */
+	ret = pcie_phy_poll_ack(dbi_base, 1);
+	if (ret)
+		return ret;
+
+	/* deassert wr signal */
+	var = data << PCIE_PHY_CTRL_DATA_LOC;
+	writel(var, dbi_base + PCIE_PHY_CTRL);
+
+	/* wait for ack de-assertion */
+	ret = pcie_phy_poll_ack(dbi_base, 0);
+	if (ret)
+		return ret;
+
+	writel(0x0, dbi_base + PCIE_PHY_CTRL);
+
+	return 0;
+}
+
+/*  Added for PCI abort handling */
+static int imx6q_pcie_abort_handler(unsigned long addr,
+		unsigned int fsr, struct pt_regs *regs)
+{
+	/*
+	 * If it was an imprecise abort, then we need to correct the
+	 * return address to be _after_ the instruction.
+	 */
+	if (fsr & (1 << 10))
+		regs->ARM_pc += 4;
+	return 0;
+}
+
+static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
+{
+	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
+
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
+			IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+			IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
+			IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
+
+	gpio_set_value(imx6_pcie->reset_gpio, 0);
+	msleep(100);
+	gpio_set_value(imx6_pcie->reset_gpio, 1);
+
+	return 0;
+}
+
+static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
+{
+	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
+	int ret;
+
+	if (gpio_is_valid(imx6_pcie->power_on_gpio))
+		gpio_set_value(imx6_pcie->power_on_gpio, 1);
+
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
+			IMX6Q_GPR1_PCIE_TEST_PD, 0 << 18);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
+			IMX6Q_GPR1_PCIE_REF_CLK_EN, 1 << 16);
+
+	ret = clk_prepare_enable(imx6_pcie->sata_ref_100m);
+	if (ret) {
+		dev_err(pp->dev, "unable to enable sata_ref_100m\n");
+		goto err_sata_ref;
+	}
+
+	ret = clk_prepare_enable(imx6_pcie->pcie_ref_125m);
+	if (ret) {
+		dev_err(pp->dev, "unable to enable pcie_ref_125m\n");
+		goto err_pcie_ref;
+	}
+
+	ret = clk_prepare_enable(imx6_pcie->lvds_gate);
+	if (ret) {
+		dev_err(pp->dev, "unable to enable lvds_gate\n");
+		goto err_lvds_gate;
+	}
+
+	ret = clk_prepare_enable(imx6_pcie->pcie_axi);
+	if (ret) {
+		dev_err(pp->dev, "unable to enable pcie_axi\n");
+		goto err_pcie_axi;
+	}
+
+	/* allow the clocks to stabilize */
+	usleep_range(200, 500);
+
+	return 0;
+
+err_pcie_axi:
+	clk_disable_unprepare(imx6_pcie->lvds_gate);
+err_lvds_gate:
+	clk_disable_unprepare(imx6_pcie->pcie_ref_125m);
+err_pcie_ref:
+	clk_disable_unprepare(imx6_pcie->sata_ref_100m);
+err_sata_ref:
+	return ret;
+
+}
+
+static void imx6_pcie_init_phy(struct pcie_port *pp)
+{
+	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
+
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+			IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);
+
+	/* configure constant input signal to the pcie ctrl and phy */
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+			IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << 12);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+			IMX6Q_GPR12_LOS_LEVEL, 9 << 4);
+
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
+			IMX6Q_GPR8_TX_DEEMPH_GEN1, 0 << 0);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
+			IMX6Q_GPR8_TX_DEEMPH_GEN2_3P5DB, 0 << 6);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
+			IMX6Q_GPR8_TX_DEEMPH_GEN2_6DB, 20 << 12);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
+			IMX6Q_GPR8_TX_SWING_FULL, 127 << 18);
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR8,
+			IMX6Q_GPR8_TX_SWING_LOW, 127 << 25);
+}
+
+static void imx6_pcie_host_init(struct pcie_port *pp)
+{
+	int count = 0;
+	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
+
+	imx6_pcie_assert_core_reset(pp);
+
+	imx6_pcie_init_phy(pp);
+
+	imx6_pcie_deassert_core_reset(pp);
+
+	dw_pcie_setup_rc(pp);
+
+	regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+			IMX6Q_GPR12_PCIE_CTL_2, 1 << 10);
+
+	while (!dw_pcie_link_up(pp)) {
+		usleep_range(100, 1000);
+		count++;
+		if (count >= 10) {
+			dev_err(pp->dev, "phy link never came up\n");
+			dev_dbg(pp->dev,
+				"DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
+				readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
+				readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
+			break;
+		}
+	}
+
+	return;
+}
+
+static int imx6_pcie_link_up(struct pcie_port *pp)
+{
+	u32 rc, ltssm, rx_valid, temp;
+
+	/* link is debug bit 36, debug register 1 starts at bit 32 */
+	rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & (0x1 << (36 - 32));
+	if (rc)
+		return -EAGAIN;
+
+	/*
+	 * From L0, initiate MAC entry to gen2 if EP/RC supports gen2.
+	 * Wait 2ms (LTSSM timeout is 24ms, PHY lock is ~5us in gen2).
+	 * If (MAC/LTSSM.state == Recovery.RcvrLock)
+	 * && (PHY/rx_valid==0) then pulse PHY/rx_reset. Transition
+	 * to gen2 is stuck
+	 */
+	pcie_phy_read(pp->dbi_base, PCIE_PHY_RX_ASIC_OUT, &rx_valid);
+	ltssm = readl(pp->dbi_base + PCIE_PHY_DEBUG_R0) & 0x3F;
+
+	if (rx_valid & 0x01)
+		return 0;
+
+	if (ltssm != 0x0d)
+		return 0;
+
+	dev_err(pp->dev, "transition to gen2 is stuck, reset PHY!\n");
+
+	pcie_phy_read(pp->dbi_base,
+		PHY_RX_OVRD_IN_LO, &temp);
+	temp |= (PHY_RX_OVRD_IN_LO_RX_DATA_EN
+		| PHY_RX_OVRD_IN_LO_RX_PLL_EN);
+	pcie_phy_write(pp->dbi_base,
+		PHY_RX_OVRD_IN_LO, temp);
+
+	usleep_range(2000, 3000);
+
+	pcie_phy_read(pp->dbi_base,
+		PHY_RX_OVRD_IN_LO, &temp);
+	temp &= ~(PHY_RX_OVRD_IN_LO_RX_DATA_EN
+		| PHY_RX_OVRD_IN_LO_RX_PLL_EN);
+	pcie_phy_write(pp->dbi_base,
+		PHY_RX_OVRD_IN_LO, temp);
+
+	return 0;
+}
+
+static struct pcie_host_ops imx6_pcie_host_ops = {
+	.link_up = imx6_pcie_link_up,
+	.host_init = imx6_pcie_host_init,
+};
+
+static int imx6_add_pcie_port(struct pcie_port *pp,
+			struct platform_device *pdev)
+{
+	int ret;
+
+	pp->irq = platform_get_irq(pdev, 0);
+	if (!pp->irq) {
+		dev_err(&pdev->dev, "failed to get irq\n");
+		return -ENODEV;
+	}
+
+	pp->root_bus_nr = -1;
+	pp->ops = &imx6_pcie_host_ops;
+
+	spin_lock_init(&pp->conf_lock);
+	ret = dw_pcie_host_init(pp);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to initialize host\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __init imx6_pcie_probe(struct platform_device *pdev)
+{
+	struct imx6_pcie *imx6_pcie;
+	struct pcie_port *pp;
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *dbi_base;
+	int ret;
+
+	imx6_pcie = devm_kzalloc(&pdev->dev, sizeof(*imx6_pcie), GFP_KERNEL);
+	if (!imx6_pcie)
+		return -ENOMEM;
+
+	pp = &imx6_pcie->pp;
+	pp->dev = &pdev->dev;
+
+	/* Added for PCI abort handling */
+	hook_fault_code(16 + 6, imx6q_pcie_abort_handler, SIGBUS, 0,
+		"imprecise external abort");
+
+	dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!dbi_base) {
+		dev_err(&pdev->dev, "dbi_base memory resource not found\n");
+		return -ENODEV;
+	}
+
+	pp->dbi_base = devm_ioremap_resource(&pdev->dev, dbi_base);
+	if (IS_ERR(pp->dbi_base)) {
+		dev_err(&pdev->dev, "unable to remap dbi_base\n");
+		ret = PTR_ERR(pp->dbi_base);
+		goto err;
+	}
+
+	/* Fetch GPIOs */
+	imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
+	if (!gpio_is_valid(imx6_pcie->reset_gpio)) {
+		dev_err(&pdev->dev, "no reset-gpio defined\n");
+		ret = -ENODEV;
+	}
+	ret = devm_gpio_request_one(&pdev->dev,
+				imx6_pcie->reset_gpio,
+				GPIOF_OUT_INIT_LOW,
+				"PCIe reset");
+	if (ret) {
+		dev_err(&pdev->dev, "unable to get reset gpio\n");
+		goto err;
+	}
+
+	imx6_pcie->power_on_gpio = of_get_named_gpio(np, "power-on-gpio", 0);
+	if (gpio_is_valid(imx6_pcie->power_on_gpio)) {
+		ret = devm_gpio_request_one(&pdev->dev,
+					imx6_pcie->power_on_gpio,
+					GPIOF_OUT_INIT_LOW,
+					"PCIe power enable");
+		if (ret) {
+			dev_err(&pdev->dev, "unable to get power-on gpio\n");
+			goto err;
+		}
+	}
+
+	imx6_pcie->wake_up_gpio = of_get_named_gpio(np, "wake-up-gpio", 0);
+	if (gpio_is_valid(imx6_pcie->wake_up_gpio)) {
+		ret = devm_gpio_request_one(&pdev->dev,
+					imx6_pcie->wake_up_gpio,
+					GPIOF_IN,
+					"PCIe wake up");
+		if (ret) {
+			dev_err(&pdev->dev, "unable to get wake-up gpio\n");
+			goto err;
+		}
+	}
+
+	imx6_pcie->disable_gpio = of_get_named_gpio(np, "disable-gpio", 0);
+	if (gpio_is_valid(imx6_pcie->disable_gpio)) {
+		ret = devm_gpio_request_one(&pdev->dev,
+					imx6_pcie->disable_gpio,
+					GPIOF_OUT_INIT_HIGH,
+					"PCIe disable endpoint");
+		if (ret) {
+			dev_err(&pdev->dev, "unable to get disable-ep gpio\n");
+			goto err;
+		}
+	}
+
+	/* Fetch clocks */
+	imx6_pcie->lvds_gate = devm_clk_get(&pdev->dev, "lvds_gate");
+	if (IS_ERR(imx6_pcie->lvds_gate)) {
+		dev_err(&pdev->dev,
+			"lvds_gate clock select missing or invalid\n");
+		ret = PTR_ERR(imx6_pcie->lvds_gate);
+		goto err;
+	}
+
+	imx6_pcie->sata_ref_100m = devm_clk_get(&pdev->dev, "sata_ref_100m");
+	if (IS_ERR(imx6_pcie->sata_ref_100m)) {
+		dev_err(&pdev->dev,
+			"sata_ref_100m clock source missing or invalid\n");
+		ret = PTR_ERR(imx6_pcie->sata_ref_100m);
+		goto err;
+	}
+
+	imx6_pcie->pcie_ref_125m = devm_clk_get(&pdev->dev, "pcie_ref_125m");
+	if (IS_ERR(imx6_pcie->pcie_ref_125m)) {
+		dev_err(&pdev->dev,
+			"pcie_ref_125m clock source missing or invalid\n");
+		ret = PTR_ERR(imx6_pcie->pcie_ref_125m);
+		goto err;
+	}
+
+	imx6_pcie->pcie_axi = devm_clk_get(&pdev->dev, "pcie_axi");
+	if (IS_ERR(imx6_pcie->pcie_axi)) {
+		dev_err(&pdev->dev,
+			"pcie_axi clock source missing or invalid\n");
+		ret = PTR_ERR(imx6_pcie->pcie_axi);
+		goto err;
+	}
+
+	/* Grab GPR config register range */
+	imx6_pcie->iomuxc_gpr =
+		 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
+	if (IS_ERR(imx6_pcie->iomuxc_gpr)) {
+		dev_err(&pdev->dev, "unable to find iomuxc registers\n");
+		ret = PTR_ERR(imx6_pcie->iomuxc_gpr);
+		goto err;
+	}
+
+	ret = imx6_add_pcie_port(pp, pdev);
+	if (ret < 0)
+		goto err;
+
+	platform_set_drvdata(pdev, imx6_pcie);
+	return 0;
+
+err:
+	return ret;
+}
+
+static const struct of_device_id imx6_pcie_of_match[] = {
+	{ .compatible = "fsl,imx6q-pcie", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
+
+static struct platform_driver imx6_pcie_driver = {
+	.driver = {
+		.name	= "imx6q-pcie",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(imx6_pcie_of_match),
+	},
+};
+
+/* Freescale PCIe driver does not allow module unload */
+
+static int __init imx6_pcie_init(void)
+{
+	return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
+}
+module_init(imx6_pcie_init);
+
+MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
+MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
+MODULE_LICENSE("GPL v2");