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Subject: [PATCH 2/2] PCI: imx6: Add support for i.MX6 PCIe controller
From: Sean Cross <xobs@kosagi.com>
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>
---
drivers/pci/host/Kconfig | 6 +
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pci-imx6.c | 575 +++++++++++++++++++++
4 files changed, 588 insertions(+), 1 deletion(-)
create mode 100644 drivers/pci/host/pci-imx6.c
--- /dev/null
+++ b/drivers/pci/host/Kconfig
@@ -0,0 +1,13 @@
+menu "PCI host controller drivers"
+ depends on PCI
+
+config PCIE_DW
+ bool
+
+config PCI_IMX6
+ bool "Freescale i.MX6 PCIe controller"
+ depends on SOC_IMX6Q
+ select PCIEPORTBUS
+ select PCIE_DW
+
+endmenu
--- /dev/null
+++ b/drivers/pci/host/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_PCIE_DW) += pcie-designware.o
+obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
--- /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");
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