Patchwork [v4,3/3] PCI: imx6: Add support for i.MX6 PCIe controller

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Submitter Sean Cross
Date Sept. 13, 2013, 9:40 a.m.
Message ID <1379065222-7275-4-git-send-email-xobs@kosagi.com>
Download mbox | patch
Permalink /patch/274701/
State New
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Comments

Sean Cross - Sept. 13, 2013, 9:40 a.m.
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>
---
 .../devicetree/bindings/pci/designware-pcie.txt    |    5 +
 arch/arm/boot/dts/imx6qdl.dtsi                     |   16 +
 arch/arm/mach-imx/Kconfig                          |    2 +
 arch/arm/mach-imx/clk-imx6q.c                      |   11 +
 drivers/pci/host/Kconfig                           |    6 +
 drivers/pci/host/Makefile                          |    1 +
 drivers/pci/host/pci-imx6.c                        |  482 ++++++++++++++++++++
 7 files changed, 523 insertions(+)
 create mode 100644 drivers/pci/host/pci-imx6.c
Bjorn Helgaas - Sept. 14, 2013, 11:54 p.m.
On Fri, Sep 13, 2013 at 3:40 AM, Sean Cross <xobs@kosagi.com> wrote:
> 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>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Please merge along with the rest of your series via the ARM tree.

> ---
>  .../devicetree/bindings/pci/designware-pcie.txt    |    5 +
>  arch/arm/boot/dts/imx6qdl.dtsi                     |   16 +
>  arch/arm/mach-imx/Kconfig                          |    2 +
>  arch/arm/mach-imx/clk-imx6q.c                      |   11 +
>  drivers/pci/host/Kconfig                           |    6 +
>  drivers/pci/host/Makefile                          |    1 +
>  drivers/pci/host/pci-imx6.c                        |  482 ++++++++++++++++++++
>  7 files changed, 523 insertions(+)
>  create mode 100644 drivers/pci/host/pci-imx6.c
>
> diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
> index eabcb4b..41d8419 100644
> --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
> @@ -21,6 +21,11 @@ Required properties:
>  - num-lanes: number of lanes to use
>  - reset-gpio: gpio pin number of power good signal
>
> +Optional properties for fsl,imx6-pcie
> +- power-on-gpio: gpio pin number of power-enable signal
> +- wake-up-gpio: gpio pin number of incoming wakeup signal
> +- disable-gpio: gpio pin number of outgoing rfkill/endpoint disable signal
> +
>  Example:
>
>  SoC specific DT Entry:
> diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
> index ccd55c2..ec72271 100644
> --- a/arch/arm/boot/dts/imx6qdl.dtsi
> +++ b/arch/arm/boot/dts/imx6qdl.dtsi
> @@ -116,6 +116,22 @@
>                         arm,data-latency = <4 2 3>;
>                 };
>
> +               pcie: pcie@0x01000000 {
> +                       compatible = "fsl,imx6-pcie", "snps,dw-pcie";
> +                       reg = <0x01ffc000 0x4000>; /* DBI */
> +
> +                       #address-cells = <3>;
> +                       #size-cells = <2>;
> +                       device_type = "pci";
> +                       ranges = <0x00000800 0 0x01f00000 0x01f00000 0 0x00080000 /* configuration space */
> +                                 0x81000000 0 0          0x01f80000 0 0x00010000 /* downstream I/O */
> +                                 0x82000000 0 0x01000000 0x01000000 0 0x00f00000>; /* non-prefetchable memory */
> +
> +                       num-lanes = <1>;
> +                       interrupts = <0 123 0x04>;
> +                       status = "disabled";
> +               };
> +
>                 pmu {
>                         compatible = "arm,cortex-a9-pmu";
>                         interrupts = <0 94 0x04>;
> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> index 29a8af6..e6ac281 100644
> --- a/arch/arm/mach-imx/Kconfig
> +++ b/arch/arm/mach-imx/Kconfig
> @@ -801,6 +801,8 @@ config SOC_IMX6Q
>         select HAVE_IMX_SRC
>         select HAVE_SMP
>         select MFD_SYSCON
> +       select MIGHT_HAVE_PCI
> +       select PCI_DOMAINS if PCI
>         select PINCTRL
>         select PINCTRL_IMX6Q
>         select PL310_ERRATA_588369 if CACHE_PL310
> diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
> index 679d49a..0a2093c 100644
> --- a/arch/arm/mach-imx/clk-imx6q.c
> +++ b/arch/arm/mach-imx/clk-imx6q.c
> @@ -622,6 +622,17 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
>         if (ret)
>                 pr_warn("failed to set up CLKO: %d\n", ret);
>
> +       /*
> +        * All existing boards with PCIe run them off LVDS1
> +        */
> +       if (IS_ENABLED(CONFIG_PCI_IMX6)) {
> +               clk_set_parent(clk[lvds1_sel], clk[sata_ref]);
> +               clk_prepare_enable(clk[lvds1_gate]);
> +               clk_prepare_enable(clk[pcie_ref_125m]);
> +               clk_prepare_enable(clk[pcie_axi]);
> +        }
> +
> +
>         /* Set initial power mode */
>         imx6q_set_lpm(WAIT_CLOCKED);
>
> 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..a3f9053
> --- /dev/null
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -0,0 +1,482 @@
> +/*
> + * 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/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/resource.h>
> +#include <linux/signal.h>
> +#include <linux/types.h>
> +#include <linux/regmap.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.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 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_DATA_LOC 0
> +#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++;
> +               udelay(1);
> +       } while ((wait_counter < max_iterations) && (val != exp_val));
> +
> +       if (val != exp_val)
> +               return -ETIMEDOUT;
> +
> +       return 0;
> +}
> +
> +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 << PCIE_PHY_STAT_DATA_LOC));
> +
> +       /* 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-assetion */
> +       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-assetion */
> +       ret = pcie_phy_poll_ack(dbi_base, 0);
> +       if (ret)
> +               return ret;
> +
> +       writel(0x0, dbi_base + PCIE_PHY_CTRL);
> +
> +       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);
> +
> +       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);
> +
> +       /* allow the clocks to stabilize */
> +       usleep_range(100, 200);
> +
> +       return 0;
> +}
> +
> +static void imx6_pcie_init_phy(struct pcie_port *pp)
> +{
> +       struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
> +
> +       /* FIXME the field name should be aligned to RM */
> +       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 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;
> +
> +       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_request_and_ioremap(&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)) {
> +               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;
> +               }
> +       }
> +
> +       /* 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 = 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,imx6-pcie", },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
> +
> +static struct platform_driver imx6_pcie_driver = {
> +       .driver = {
> +               .name   = "imx6-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 pcie_init(void)
> +{
> +       return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
> +}
> +subsys_initcall(pcie_init);
> +
> +MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
> +MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Sean Cross - Sept. 16, 2013, 5:57 a.m.
On 14/9/13 7:50 AM, Tim Harvey wrote:
> Sean,
>
> Thanks for your work - I'm glad to see an i.MX6 PCIe host controller 
> driver finally getting some upstream attention!
>
> I've tested this under several scenarios and am running into some issues.
>
> I found that on an IMX6DL I had to enable the sata_ref_100m clock 
> additionally or a readl to the host address registers would hang (like 
> the core had no clock).  I've run into this before with the IMX6DL and 
> don't quite understand why the core would be clocked off the sata clock.
>
> When going through a switch (Gateworks GW5400-B has a PLX PEX8609 
> 8-port PCIe switch) I found that the CPU would randomly hang sometime 
> after bootup.  I found that installing an abort handler (from the 
> Freescale BSP) seemed to resolve this.  Additionally when going 
> through a switch, I could not read config space of the switch dev or 
> anything beyond it so it doesn't look like the driver supports 
> switches/bridges.
As Richard Zhu mentioned, all devices should have sata_ref_100m 
enabled.  I'll make this change in v5.

I don't have a PCIe switch handy, so I can't test your handler, but the 
reasoning does make sense.  I'll add the abort handler code into the 
driver.  I'd be curious to know if this is a Designware limitation, or 
if it's the sort of thing that this hardware is capable of supporting.

Freescale recommends using the SATA clock to drive the external bus.  I 
don't quite understand the reasoning, but it seems to have to do with a 
number of dividers and multipliers it goes through, some of which are 
fixed, and they all expect a 100 MHz clock.  They are starting to change 
the names of the clocks in the documentation from "SATA" and "PCIE" to 
"100Mhz" and "125Mhz" because of the ambiguity.

--
Sean Cross
Shawn Guo - Sept. 16, 2013, 6:06 a.m.
On Fri, Sep 13, 2013 at 09:40:22AM +0000, Sean Cross wrote:
> 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>
> ---
>  .../devicetree/bindings/pci/designware-pcie.txt    |    5 +
>  arch/arm/boot/dts/imx6qdl.dtsi                     |   16 +
>  arch/arm/mach-imx/Kconfig                          |    2 +
>  arch/arm/mach-imx/clk-imx6q.c                      |   11 +
>  drivers/pci/host/Kconfig                           |    6 +
>  drivers/pci/host/Makefile                          |    1 +
>  drivers/pci/host/pci-imx6.c                        |  482 ++++++++++++++++++++
>  7 files changed, 523 insertions(+)
>  create mode 100644 drivers/pci/host/pci-imx6.c
> 
> diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
> index eabcb4b..41d8419 100644
> --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
> @@ -21,6 +21,11 @@ Required properties:
>  - num-lanes: number of lanes to use
>  - reset-gpio: gpio pin number of power good signal
>  
> +Optional properties for fsl,imx6-pcie
> +- power-on-gpio: gpio pin number of power-enable signal
> +- wake-up-gpio: gpio pin number of incoming wakeup signal
> +- disable-gpio: gpio pin number of outgoing rfkill/endpoint disable signal
> +
>  Example:
>  
>  SoC specific DT Entry:
> diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
> index ccd55c2..ec72271 100644
> --- a/arch/arm/boot/dts/imx6qdl.dtsi
> +++ b/arch/arm/boot/dts/imx6qdl.dtsi
> @@ -116,6 +116,22 @@
>  			arm,data-latency = <4 2 3>;
>  		};
>  
> +		pcie: pcie@0x01000000 {
> +			compatible = "fsl,imx6-pcie", "snps,dw-pcie";

We generally use particular SoC name to specify the compatible string.
So "fsl,imx6q-pcie" will be more appropriate.

> +			reg = <0x01ffc000 0x4000>; /* DBI */
> +

Nit: please drop this blank line.

> +			#address-cells = <3>;
> +			#size-cells = <2>;
> +			device_type = "pci";
> +			ranges = <0x00000800 0 0x01f00000 0x01f00000 0 0x00080000 /* configuration space */
> +				  0x81000000 0 0          0x01f80000 0 0x00010000 /* downstream I/O */
> +				  0x82000000 0 0x01000000 0x01000000 0 0x00f00000>; /* non-prefetchable memory */
> +

Ditto

> +			num-lanes = <1>;
> +			interrupts = <0 123 0x04>;
> +			status = "disabled";
> +		};
> +
>  		pmu {
>  			compatible = "arm,cortex-a9-pmu";
>  			interrupts = <0 94 0x04>;
> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> index 29a8af6..e6ac281 100644
> --- a/arch/arm/mach-imx/Kconfig
> +++ b/arch/arm/mach-imx/Kconfig
> @@ -801,6 +801,8 @@ config SOC_IMX6Q
>  	select HAVE_IMX_SRC
>  	select HAVE_SMP
>  	select MFD_SYSCON
> +	select MIGHT_HAVE_PCI
> +	select PCI_DOMAINS if PCI
>  	select PINCTRL
>  	select PINCTRL_IMX6Q
>  	select PL310_ERRATA_588369 if CACHE_PL310
> diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
> index 679d49a..0a2093c 100644
> --- a/arch/arm/mach-imx/clk-imx6q.c
> +++ b/arch/arm/mach-imx/clk-imx6q.c
> @@ -622,6 +622,17 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
>  	if (ret)
>  		pr_warn("failed to set up CLKO: %d\n", ret);
>  
> +	/*
> +	 * All existing boards with PCIe run them off LVDS1
> +	 */
> +	if (IS_ENABLED(CONFIG_PCI_IMX6)) {
> +		clk_set_parent(clk[lvds1_sel], clk[sata_ref]);
> +		clk_prepare_enable(clk[lvds1_gate]);
> +		clk_prepare_enable(clk[pcie_ref_125m]);
> +		clk_prepare_enable(clk[pcie_axi]);
> +        }

Use tab instead of spaces, please.

> +
> +

Drop one blank line.

>  	/* Set initial power mode */
>  	imx6q_set_lpm(WAIT_CLOCKED);
>  
> 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..a3f9053
> --- /dev/null
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -0,0 +1,482 @@
> +/*
> + * 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/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/resource.h>
> +#include <linux/signal.h>
> +#include <linux/types.h>
> +#include <linux/regmap.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.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 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_DATA_LOC 0
> +#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)

(1 << 5), please.

> +#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1<<3)

Ditto

> +
> +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++;
> +		udelay(1);
> +	} while ((wait_counter < max_iterations) && (val != exp_val));
> +
> +	if (val != exp_val)
> +		return -ETIMEDOUT;
> +
> +	return 0;
> +}
> +
> +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 << PCIE_PHY_STAT_DATA_LOC));

One unnecessary parentheses.

> +
> +	/* 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-assetion */
> +	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-assetion */
> +	ret = pcie_phy_poll_ack(dbi_base, 0);
> +	if (ret)
> +		return ret;
> +
> +	writel(0x0, dbi_base + PCIE_PHY_CTRL);
> +
> +	return 0;
> +}
> +
> +static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
> +{
> +	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);

Nit: have a blank line here.

> +	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);
> +
> +	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);
> +
> +	/* allow the clocks to stabilize */
> +	usleep_range(100, 200);
> +
> +	return 0;
> +}
> +
> +static void imx6_pcie_init_phy(struct pcie_port *pp)
> +{
> +	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
> +
> +	/* FIXME the field name should be aligned to RM */

Why cannot this be fixed right now?

> +	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
> +	 */

	/*
	 * Multiple lines comment
	 * ...
	 */

> +	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 add_pcie_port(struct pcie_port *pp, struct platform_device *pdev)

imx6_pcie_add_port to have the proper namespace?

> +{
> +	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;
> +
> +	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_request_and_ioremap(&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;
> +	}

See kerneldoc of devm_request_and_ioremap().  I believe that the help
already takes care of printing error messages.

> +
> +	/* Fetch GPIOs */
> +	imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
> +	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> +		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;
> +		}
> +	}

The reset-gpio is not optional but required.  So if we do not have a
valid reset-gpio, the probe should fail.  And that's why we can access
reset_gpio in imx6_pcie_assert_core_reset() without checking if it's
valid.

> +
> +	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;
> +		}
> +	}
> +
> +	/* 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 = 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,imx6-pcie", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
> +
> +static struct platform_driver imx6_pcie_driver = {
> +	.driver = {
> +		.name	= "imx6-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 pcie_init(void)
> +{
> +	return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
> +}
> +subsys_initcall(pcie_init);

Any reason why it cannot be module_init()?

Shawn

> +
> +MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
> +MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 1.7.9.5
>
Jingoo Han - Sept. 16, 2013, 6:22 a.m.
On Friday, September 13, 2013 6:40 PM, Sean Cross wrote:
> 
> 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>

It looks good. :-)
But, I added some minor comments.

> ---
>  .../devicetree/bindings/pci/designware-pcie.txt    |    5 +
>  arch/arm/boot/dts/imx6qdl.dtsi                     |   16 +
>  arch/arm/mach-imx/Kconfig                          |    2 +
>  arch/arm/mach-imx/clk-imx6q.c                      |   11 +
>  drivers/pci/host/Kconfig                           |    6 +
>  drivers/pci/host/Makefile                          |    1 +
>  drivers/pci/host/pci-imx6.c                        |  482 ++++++++++++++++++++
>  7 files changed, 523 insertions(+)
>  create mode 100644 drivers/pci/host/pci-imx6.c

[.....]

> diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
> index 679d49a..0a2093c 100644
> --- a/arch/arm/mach-imx/clk-imx6q.c
> +++ b/arch/arm/mach-imx/clk-imx6q.c
> @@ -622,6 +622,17 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
>  	if (ret)
>  		pr_warn("failed to set up CLKO: %d\n", ret);
> 
> +	/*
> +	 * All existing boards with PCIe run them off LVDS1
> +	 */
> +	if (IS_ENABLED(CONFIG_PCI_IMX6)) {
> +		clk_set_parent(clk[lvds1_sel], clk[sata_ref]);
> +		clk_prepare_enable(clk[lvds1_gate]);
> +		clk_prepare_enable(clk[pcie_ref_125m]);
> +		clk_prepare_enable(clk[pcie_axi]);
> +        }

Please use tab instead of spaces.

> +
> +

Please remove a duplicated line.

[.....]

> +#include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/resource.h>
> +#include <linux/signal.h>
> +#include <linux/types.h>
> +#include <linux/regmap.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>

If possible, please re-order in alphabetical order.

[.....]

> +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",

Please insert space between pp->dev, and "DEBUG_R0 in order to fix the following
checkpatch error.

ERROR: space required after that ',' (ctx:VxV)
#407: FILE: drivers/pci/host/pci-imx6.c:276:
+                       dev_dbg(pp->dev,"DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",

Best regards,
Jingoo Han
Sean Cross - Sept. 16, 2013, 6:54 a.m.
On 16/9/13 2:06 PM, Shawn Guo wrote:
> On Fri, Sep 13, 2013 at 09:40:22AM +0000, Sean Cross wrote:
>> 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>
>> ---
>>   .../devicetree/bindings/pci/designware-pcie.txt    |    5 +
>>   arch/arm/boot/dts/imx6qdl.dtsi                     |   16 +
>>   arch/arm/mach-imx/Kconfig                          |    2 +
>>   arch/arm/mach-imx/clk-imx6q.c                      |   11 +
>>   drivers/pci/host/Kconfig                           |    6 +
>>   drivers/pci/host/Makefile                          |    1 +
>>   drivers/pci/host/pci-imx6.c                        |  482 ++++++++++++++++++++
>>   7 files changed, 523 insertions(+)
>>   create mode 100644 drivers/pci/host/pci-imx6.c
>>
>> diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
>> index eabcb4b..41d8419 100644
>> --- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
>> +++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
>> @@ -21,6 +21,11 @@ Required properties:
>>   - num-lanes: number of lanes to use
>>   - reset-gpio: gpio pin number of power good signal
>>   
>> +Optional properties for fsl,imx6-pcie
>> +- power-on-gpio: gpio pin number of power-enable signal
>> +- wake-up-gpio: gpio pin number of incoming wakeup signal
>> +- disable-gpio: gpio pin number of outgoing rfkill/endpoint disable signal
>> +
>>   Example:
>>   
>>   SoC specific DT Entry:
>> diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
>> index ccd55c2..ec72271 100644
>> --- a/arch/arm/boot/dts/imx6qdl.dtsi
>> +++ b/arch/arm/boot/dts/imx6qdl.dtsi
>> @@ -116,6 +116,22 @@
>>   			arm,data-latency = <4 2 3>;
>>   		};
>>   
>> +		pcie: pcie@0x01000000 {
>> +			compatible = "fsl,imx6-pcie", "snps,dw-pcie";
> We generally use particular SoC name to specify the compatible string.
> So "fsl,imx6q-pcie" will be more appropriate.
Any reason to specify imx6q in particular?  It's also present on the 
imx6d, imx6dl, and imx6s (basically, everything but the imx6sl).
>
>>   	/* Set initial power mode */
>>   	imx6q_set_lpm(WAIT_CLOCKED);
>>   
>> 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..a3f9053
>> --- /dev/null
>> +++ b/drivers/pci/host/pci-imx6.c
>> @@ -0,0 +1,482 @@
>> +/*
>> + * 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/delay.h>
>> +#include <linux/gpio.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of_gpio.h>
>> +#include <linux/pci.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/resource.h>
>> +#include <linux/signal.h>
>> +#include <linux/types.h>
>> +#include <linux/regmap.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.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 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_DATA_LOC 0
>> +#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)
> (1 << 5), please.
>
>> +#define PHY_RX_OVRD_IN_LO_RX_PLL_EN (1<<3)
> Ditto
>
>> +
>> +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++;
>> +		udelay(1);
>> +	} while ((wait_counter < max_iterations) && (val != exp_val));
>> +
>> +	if (val != exp_val)
>> +		return -ETIMEDOUT;
>> +
>> +	return 0;
>> +}
>> +
>> +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 << PCIE_PHY_STAT_DATA_LOC));
> One unnecessary parentheses.
>
>> +
>> +	/* 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-assetion */
>> +	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-assetion */
>> +	ret = pcie_phy_poll_ack(dbi_base, 0);
>> +	if (ret)
>> +		return ret;
>> +
>> +	writel(0x0, dbi_base + PCIE_PHY_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
>> +{
>> +	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
> Nit: have a blank line here.
>
>> +	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);
>> +
>> +	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);
>> +
>> +	/* allow the clocks to stabilize */
>> +	usleep_range(100, 200);
>> +
>> +	return 0;
>> +}
>> +
>> +static void imx6_pcie_init_phy(struct pcie_port *pp)
>> +{
>> +	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
>> +
>> +	/* FIXME the field name should be aligned to RM */
> Why cannot this be fixed right now?
The FIXME is left over from an earlier incarnation.  I don't think it's 
relevant anymore.  I'll drop it.
>> +	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
>> +	 */
> 	/*
> 	 * Multiple lines comment
> 	 * ...
> 	 */
>
>> +	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 add_pcie_port(struct pcie_port *pp, struct platform_device *pdev)
> imx6_pcie_add_port to have the proper namespace?
I thought this was the style for pci drivers, because
>> +{
>> +	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;
>> +
>> +	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_request_and_ioremap(&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;
>> +	}
> See kerneldoc of devm_request_and_ioremap().  I believe that the help
> already takes care of printing error messages.
This is a very good catch.  devm_request_and_ioremap() is deprecated and 
in the process of getting removed.  I'll replace the call and see what's 
best in terms of error messages.
>> +
>> +	/* Fetch GPIOs */
>> +	imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
>> +	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
>> +		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;
>> +		}
>> +	}
> The reset-gpio is not optional but required.  So if we do not have a
> valid reset-gpio, the probe should fail.  And that's why we can access
> reset_gpio in imx6_pcie_assert_core_reset() without checking if it's
> valid.
That is a very good call.  I'll make the reset-gpio actually required.
>> +
>> +	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;
>> +		}
>> +	}
>> +
>> +	/* 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 = 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,imx6-pcie", },
>> +	{},
>> +};
>> +MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
>> +
>> +static struct platform_driver imx6_pcie_driver = {
>> +	.driver = {
>> +		.name	= "imx6-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 pcie_init(void)
>> +{
>> +	return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
>> +}
>> +subsys_initcall(pcie_init);
> Any reason why it cannot be module_init()?
>
No reason whatsoever.  I'll rename pcie_init to module_init.
Shawn Guo - Sept. 16, 2013, 9:01 a.m.
On Mon, Sep 16, 2013 at 02:54:32PM +0800, Sean Cross wrote:
> >>@@ -116,6 +116,22 @@
> >>  			arm,data-latency = <4 2 3>;
> >>  		};
> >>+		pcie: pcie@0x01000000 {
> >>+			compatible = "fsl,imx6-pcie", "snps,dw-pcie";
> >We generally use particular SoC name to specify the compatible string.
> >So "fsl,imx6q-pcie" will be more appropriate.
> Any reason to specify imx6q in particular?  It's also present on the
> imx6d, imx6dl, and imx6s (basically, everything but the imx6sl).

The compatible naming is not about coverage but versioning.  We
generally encode the name of the SoC that firstly integrates the block
to specify the version.

Shawn
Jingoo Han - Sept. 16, 2013, 10:53 p.m.
On Monday, September 16, 2013 6:02 PM, Shawn Guo wrote:
> On Mon, Sep 16, 2013 at 02:54:32PM +0800, Sean Cross wrote:
> > >>@@ -116,6 +116,22 @@
> > >>  			arm,data-latency = <4 2 3>;
> > >>  		};
> > >>+		pcie: pcie@0x01000000 {
> > >>+			compatible = "fsl,imx6-pcie", "snps,dw-pcie";
> > >We generally use particular SoC name to specify the compatible string.
> > >So "fsl,imx6q-pcie" will be more appropriate.
> > Any reason to specify imx6q in particular?  It's also present on the
> > imx6d, imx6dl, and imx6s (basically, everything but the imx6sl).
> 
> The compatible naming is not about coverage but versioning.  We
> generally encode the name of the SoC that firstly integrates the block
> to specify the version.
> 

Yes, you're right. :-)
The name of the first SoC would be used.

Best regards,
Jingoo Han

Patch

diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
index eabcb4b..41d8419 100644
--- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
@@ -21,6 +21,11 @@  Required properties:
 - num-lanes: number of lanes to use
 - reset-gpio: gpio pin number of power good signal
 
+Optional properties for fsl,imx6-pcie
+- power-on-gpio: gpio pin number of power-enable signal
+- wake-up-gpio: gpio pin number of incoming wakeup signal
+- disable-gpio: gpio pin number of outgoing rfkill/endpoint disable signal
+
 Example:
 
 SoC specific DT Entry:
diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
index ccd55c2..ec72271 100644
--- a/arch/arm/boot/dts/imx6qdl.dtsi
+++ b/arch/arm/boot/dts/imx6qdl.dtsi
@@ -116,6 +116,22 @@ 
 			arm,data-latency = <4 2 3>;
 		};
 
+		pcie: pcie@0x01000000 {
+			compatible = "fsl,imx6-pcie", "snps,dw-pcie";
+			reg = <0x01ffc000 0x4000>; /* DBI */
+
+			#address-cells = <3>;
+			#size-cells = <2>;
+			device_type = "pci";
+			ranges = <0x00000800 0 0x01f00000 0x01f00000 0 0x00080000 /* configuration space */
+				  0x81000000 0 0          0x01f80000 0 0x00010000 /* downstream I/O */
+				  0x82000000 0 0x01000000 0x01000000 0 0x00f00000>; /* non-prefetchable memory */
+
+			num-lanes = <1>;
+			interrupts = <0 123 0x04>;
+			status = "disabled";
+		};
+
 		pmu {
 			compatible = "arm,cortex-a9-pmu";
 			interrupts = <0 94 0x04>;
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 29a8af6..e6ac281 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -801,6 +801,8 @@  config SOC_IMX6Q
 	select HAVE_IMX_SRC
 	select HAVE_SMP
 	select MFD_SYSCON
+	select MIGHT_HAVE_PCI
+	select PCI_DOMAINS if PCI
 	select PINCTRL
 	select PINCTRL_IMX6Q
 	select PL310_ERRATA_588369 if CACHE_PL310
diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
index 679d49a..0a2093c 100644
--- a/arch/arm/mach-imx/clk-imx6q.c
+++ b/arch/arm/mach-imx/clk-imx6q.c
@@ -622,6 +622,17 @@  static void __init imx6q_clocks_init(struct device_node *ccm_node)
 	if (ret)
 		pr_warn("failed to set up CLKO: %d\n", ret);
 
+	/*
+	 * All existing boards with PCIe run them off LVDS1
+	 */
+	if (IS_ENABLED(CONFIG_PCI_IMX6)) {
+		clk_set_parent(clk[lvds1_sel], clk[sata_ref]);
+		clk_prepare_enable(clk[lvds1_gate]);
+		clk_prepare_enable(clk[pcie_ref_125m]);
+		clk_prepare_enable(clk[pcie_axi]);
+        }
+
+
 	/* Set initial power mode */
 	imx6q_set_lpm(WAIT_CLOCKED);
 
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..a3f9053
--- /dev/null
+++ b/drivers/pci/host/pci-imx6.c
@@ -0,0 +1,482 @@ 
+/*
+ * 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/delay.h>
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/resource.h>
+#include <linux/signal.h>
+#include <linux/types.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/imx6q-iomuxc-gpr.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 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_DATA_LOC 0
+#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++;
+		udelay(1);
+	} while ((wait_counter < max_iterations) && (val != exp_val));
+
+	if (val != exp_val)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+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 << PCIE_PHY_STAT_DATA_LOC));
+
+	/* 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-assetion */
+	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-assetion */
+	ret = pcie_phy_poll_ack(dbi_base, 0);
+	if (ret)
+		return ret;
+
+	writel(0x0, dbi_base + PCIE_PHY_CTRL);
+
+	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);
+
+	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);
+
+	/* allow the clocks to stabilize */
+	usleep_range(100, 200);
+
+	return 0;
+}
+
+static void imx6_pcie_init_phy(struct pcie_port *pp)
+{
+	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
+
+	/* FIXME the field name should be aligned to RM */
+	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 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;
+
+	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_request_and_ioremap(&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)) {
+		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;
+		}
+	}
+
+	/* 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 = 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,imx6-pcie", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);
+
+static struct platform_driver imx6_pcie_driver = {
+	.driver = {
+		.name	= "imx6-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 pcie_init(void)
+{
+	return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
+}
+subsys_initcall(pcie_init);
+
+MODULE_AUTHOR("Sean Cross <xobs@kosagi.com>");
+MODULE_DESCRIPTION("Freescale i.MX6 PCIe host controller driver");
+MODULE_LICENSE("GPL v2");