diff mbox series

[v2,6/8] pci: Add DW PCIe controller support for iMX8MP SoC

Message ID 20240226080433.3307154-7-sumit.garg@linaro.org
State Superseded
Headers show
Series imx8mp: Enable PCIe/NVMe support | expand

Commit Message

Sumit Garg Feb. 26, 2024, 8:04 a.m. UTC
pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
tied to quite old port of pcie_designware driver from Linux which
suffices only iMX6 specific needs.

But currently we have the common DWC specific bits which alligns pretty
well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
add support for other iMX8 variants to this driver.

iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
can reuse the generic PHY infrastructure to power on PCIe PHY.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/pci/Kconfig       |   8 +
 drivers/pci/Makefile      |   1 +
 drivers/pci/pcie_dw_imx.c | 314 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 323 insertions(+)
 create mode 100644 drivers/pci/pcie_dw_imx.c

Comments

Marek Vasut Feb. 26, 2024, 8:44 a.m. UTC | #1
On 2/26/24 9:04 AM, Sumit Garg wrote:
> pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
> tied to quite old port of pcie_designware driver from Linux which
> suffices only iMX6 specific needs.

It is probably hand-rolled, but it does suck, that's true.

> But currently we have the common DWC specific bits which alligns pretty
> well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
> bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
> add support for other iMX8 variants to this driver.
> 
> iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
> can reuse the generic PHY infrastructure to power on PCIe PHY.

[...]

> +static int pcie_dw_imx_of_to_plat(struct udevice *dev)
> +{
> +	struct pcie_dw_imx *priv = dev_get_priv(dev);
> +	ofnode gpr;
> +	int ret;
> +
> +	/* Get the controller base address */
> +	priv->dw.dbi_base = (void *)dev_read_addr_name(dev, "dbi");
> +	if ((fdt_addr_t)priv->dw.dbi_base == FDT_ADDR_T_NONE) {
> +		dev_err(dev, "failed to get dbi_base address\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Get the config space base address and size */
> +	priv->dw.cfg_base = (void *)dev_read_addr_size_name(dev, "config",
> +							    &priv->dw.cfg_size);
> +	if ((fdt_addr_t)priv->dw.cfg_base == FDT_ADDR_T_NONE) {
> +		dev_err(dev, "failed to get cfg_base address\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = clk_get_bulk(dev, &priv->clks);
> +	if (ret) {
> +		dev_err(dev, "failed to get PCIe clks\n");
> +		return ret;
> +	}
> +
> +	ret = reset_get_by_name(dev, "apps", &priv->apps_reset);
> +	if (ret) {
> +		dev_err(dev,
> +			"Failed to get PCIe apps reset control\n");
> +		return ret;
> +	}
> +
> +	ret = gpio_request_by_name(dev, "reset-gpio", 0, &priv->reset_gpio,
> +				   (GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE));
> +	if (ret) {
> +		dev_err(dev, "unable to get reset-gpio\n");
> +		return ret;
> +	}
> +
> +	ret = generic_phy_get_by_name(dev, "pcie-phy", &priv->phy);
> +	if (ret) {
> +		dev_err(dev, "failed to get pcie phy\n");
> +		return ret;
> +	}
> +
> +	gpr = ofnode_by_compatible(ofnode_null(), "fsl,imx8mp-iomuxc-gpr");
> +	if (ofnode_equal(gpr, ofnode_null())) {
> +		dev_err(dev, "unable to find GPR node\n");
> +		return -ENODEV;
> +	}

You likely need a fail path here too, to undo allocation and co.
Sumit Garg Feb. 26, 2024, 12:52 p.m. UTC | #2
On Mon, 26 Feb 2024 at 14:24, Marek Vasut <marex@denx.de> wrote:
>
> On 2/26/24 9:04 AM, Sumit Garg wrote:
> > pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
> > tied to quite old port of pcie_designware driver from Linux which
> > suffices only iMX6 specific needs.
>
> It is probably hand-rolled, but it does suck, that's true.
>
> > But currently we have the common DWC specific bits which alligns pretty
> > well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
> > bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
> > add support for other iMX8 variants to this driver.
> >
> > iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
> > can reuse the generic PHY infrastructure to power on PCIe PHY.
>
> [...]
>
> > +static int pcie_dw_imx_of_to_plat(struct udevice *dev)
> > +{
> > +     struct pcie_dw_imx *priv = dev_get_priv(dev);
> > +     ofnode gpr;
> > +     int ret;
> > +
> > +     /* Get the controller base address */
> > +     priv->dw.dbi_base = (void *)dev_read_addr_name(dev, "dbi");
> > +     if ((fdt_addr_t)priv->dw.dbi_base == FDT_ADDR_T_NONE) {
> > +             dev_err(dev, "failed to get dbi_base address\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     /* Get the config space base address and size */
> > +     priv->dw.cfg_base = (void *)dev_read_addr_size_name(dev, "config",
> > +                                                         &priv->dw.cfg_size);
> > +     if ((fdt_addr_t)priv->dw.cfg_base == FDT_ADDR_T_NONE) {
> > +             dev_err(dev, "failed to get cfg_base address\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     ret = clk_get_bulk(dev, &priv->clks);
> > +     if (ret) {
> > +             dev_err(dev, "failed to get PCIe clks\n");
> > +             return ret;
> > +     }
> > +
> > +     ret = reset_get_by_name(dev, "apps", &priv->apps_reset);
> > +     if (ret) {
> > +             dev_err(dev,
> > +                     "Failed to get PCIe apps reset control\n");
> > +             return ret;
> > +     }
> > +
> > +     ret = gpio_request_by_name(dev, "reset-gpio", 0, &priv->reset_gpio,
> > +                                (GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE));
> > +     if (ret) {
> > +             dev_err(dev, "unable to get reset-gpio\n");
> > +             return ret;
> > +     }
> > +
> > +     ret = generic_phy_get_by_name(dev, "pcie-phy", &priv->phy);
> > +     if (ret) {
> > +             dev_err(dev, "failed to get pcie phy\n");
> > +             return ret;
> > +     }
> > +
> > +     gpr = ofnode_by_compatible(ofnode_null(), "fsl,imx8mp-iomuxc-gpr");
> > +     if (ofnode_equal(gpr, ofnode_null())) {
> > +             dev_err(dev, "unable to find GPR node\n");
> > +             return -ENODEV;
> > +     }
>
> You likely need a fail path here too, to undo allocation and co.

Ack.

-Sumit
Adam Ford Feb. 27, 2024, 11:13 p.m. UTC | #3
On Mon, Feb 26, 2024 at 2:05 AM Sumit Garg <sumit.garg@linaro.org> wrote:
>
> pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
> tied to quite old port of pcie_designware driver from Linux which
> suffices only iMX6 specific needs.
>
> But currently we have the common DWC specific bits which alligns pretty
> well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
> bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
> add support for other iMX8 variants to this driver.
>
> iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
> can reuse the generic PHY infrastructure to power on PCIe PHY.
>
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> ---
>  drivers/pci/Kconfig       |   8 +
>  drivers/pci/Makefile      |   1 +
>  drivers/pci/pcie_dw_imx.c | 314 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 323 insertions(+)
>  create mode 100644 drivers/pci/pcie_dw_imx.c
>
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index 463ec47eb92d..7edbf35004a9 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -413,4 +413,12 @@ config PCIE_STARFIVE_JH7110
>           Say Y here if you want to enable PLDA XpressRich PCIe controller
>           support on StarFive JH7110 SoC.
>
> +config PCIE_DW_IMX
> +       bool "i.MX DW PCIe controller support"
> +       depends on ARCH_IMX8M

I think this also needs to depend on REGMAP to prevent build errors.


adam

> +       select PCIE_DW_COMMON
> +       help
> +         Say Y here if you want to enable DW PCIe controller support on
> +         iMX SoCs.
> +
>  endif
> diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> index 72ef8b4bc772..2927c519129b 100644
> --- a/drivers/pci/Makefile
> +++ b/drivers/pci/Makefile
> @@ -53,3 +53,4 @@ obj-$(CONFIG_PCIE_UNIPHIER) += pcie_uniphier.o
>  obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
>  obj-$(CONFIG_PCIE_PLDA_COMMON) += pcie_plda_common.o
>  obj-$(CONFIG_PCIE_STARFIVE_JH7110) += pcie_starfive_jh7110.o
> +obj-$(CONFIG_PCIE_DW_IMX) += pcie_dw_imx.o
> diff --git a/drivers/pci/pcie_dw_imx.c b/drivers/pci/pcie_dw_imx.c
> new file mode 100644
> index 000000000000..7856823c9188
> --- /dev/null
> +++ b/drivers/pci/pcie_dw_imx.c
> @@ -0,0 +1,314 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2024 Linaro Ltd.
> + *
> + * Author: Sumit Garg <sumit.garg@linaro.org>
> + */
> +
> +#include <asm/io.h>
> +#include <asm-generic/gpio.h>
> +#include <clk.h>
> +#include <dm.h>
> +#include <dm/device_compat.h>
> +#include <generic-phy.h>
> +#include <linux/bitops.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/iopoll.h>
> +#include <log.h>
> +#include <pci.h>
> +#include <regmap.h>
> +#include <reset.h>
> +#include <syscon.h>
> +#include <time.h>
> +
> +#include "pcie_dw_common.h"
> +
> +#define PCIE_LINK_CAPABILITY           0x7c
> +#define TARGET_LINK_SPEED_MASK         0xf
> +#define LINK_SPEED_GEN_1               0x1
> +#define LINK_SPEED_GEN_2               0x2
> +#define LINK_SPEED_GEN_3               0x3
> +
> +#define PCIE_MISC_CONTROL_1_OFF                0x8bc
> +#define PCIE_DBI_RO_WR_EN              BIT(0)
> +
> +#define PCIE_PORT_DEBUG0                       0x728
> +#define PCIE_PORT_DEBUG1                       0x72c
> +#define PCIE_PORT_DEBUG1_LINK_UP               BIT(4)
> +#define PCIE_PORT_DEBUG1_LINK_IN_TRAINING      BIT(29)
> +
> +#define PCIE_LINK_UP_TIMEOUT_MS                100
> +
> +#define IOMUXC_GPR14_OFFSET                    0x38
> +#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN     BIT(10)
> +#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE                BIT(11)
> +
> +struct pcie_dw_imx {
> +       /* Must be first member of the struct */
> +       struct pcie_dw                  dw;
> +       struct regmap                   *iomuxc_gpr;
> +       struct clk_bulk                 clks;
> +       struct gpio_desc                reset_gpio;
> +       struct reset_ctl                apps_reset;
> +       struct phy                      phy;
> +};
> +
> +static void pcie_dw_configure(struct pcie_dw_imx *priv, u32 cap_speed)
> +{
> +       dw_pcie_dbi_write_enable(&priv->dw, true);
> +
> +       clrsetbits_le32(priv->dw.dbi_base + PCIE_LINK_CAPABILITY,
> +                       TARGET_LINK_SPEED_MASK, cap_speed);
> +
> +       dw_pcie_dbi_write_enable(&priv->dw, false);
> +}
> +
> +static void imx_pcie_ltssm_enable(struct pcie_dw_imx *priv)
> +{
> +       reset_deassert(&priv->apps_reset);
> +}
> +
> +static void imx_pcie_ltssm_disable(struct pcie_dw_imx *priv)
> +{
> +       reset_assert(&priv->apps_reset);
> +}
> +
> +static bool is_link_up(u32 val)
> +{
> +       return ((val & PCIE_PORT_DEBUG1_LINK_UP) &&
> +               (!(val & PCIE_PORT_DEBUG1_LINK_IN_TRAINING)));
> +}
> +
> +static int wait_link_up(struct pcie_dw_imx *priv)
> +{
> +       u32 val;
> +
> +       return readl_poll_sleep_timeout(priv->dw.dbi_base + PCIE_PORT_DEBUG1,
> +                                       val, is_link_up(val), 10000, 100000);
> +}
> +
> +static int pcie_link_up(struct pcie_dw_imx *priv, u32 cap_speed)
> +{
> +       int ret;
> +
> +       /* DW pre link configurations */
> +       pcie_dw_configure(priv, cap_speed);
> +
> +       /* Initiate link training */
> +       imx_pcie_ltssm_enable(priv);
> +
> +       /* Check that link was established */
> +       ret = wait_link_up(priv);
> +       if (ret)
> +               imx_pcie_ltssm_disable(priv);
> +
> +       return ret;
> +}
> +
> +static int imx_pcie_assert_core_reset(struct pcie_dw_imx *priv)
> +{
> +       if (dm_gpio_is_valid(&priv->reset_gpio)) {
> +               dm_gpio_set_value(&priv->reset_gpio, 1);
> +               mdelay(20);
> +       }
> +
> +       return reset_assert(&priv->apps_reset);
> +}
> +
> +static int imx_pcie_clk_enable(struct pcie_dw_imx *priv)
> +{
> +       int ret;
> +
> +       ret = clk_enable_bulk(&priv->clks);
> +       if (ret)
> +               return ret;
> +
> +       /*
> +        * Set the over ride low and enabled make sure that
> +        * REF_CLK is turned on.
> +        */
> +       regmap_update_bits(priv->iomuxc_gpr, IOMUXC_GPR14_OFFSET,
> +                          IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE, 0);
> +       regmap_update_bits(priv->iomuxc_gpr, IOMUXC_GPR14_OFFSET,
> +                          IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
> +                          IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
> +
> +       /* allow the clocks to stabilize */
> +       udelay(500);
> +
> +       return 0;
> +}
> +
> +static void imx_pcie_deassert_core_reset(struct pcie_dw_imx *priv)
> +{
> +       if (!dm_gpio_is_valid(&priv->reset_gpio))
> +               return;
> +
> +       mdelay(100);
> +       dm_gpio_set_value(&priv->reset_gpio, 0);
> +       /* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
> +       mdelay(100);
> +}
> +
> +static int pcie_dw_imx_probe(struct udevice *dev)
> +{
> +       struct pcie_dw_imx *priv = dev_get_priv(dev);
> +       struct udevice *ctlr = pci_get_controller(dev);
> +       struct pci_controller *hose = dev_get_uclass_priv(ctlr);
> +       int ret;
> +
> +       ret = imx_pcie_assert_core_reset(priv);
> +       if (ret) {
> +               dev_err(dev, "failed to assert core reset\n");
> +               return ret;
> +       }
> +
> +       ret = imx_pcie_clk_enable(priv);
> +       if (ret) {
> +               dev_err(dev, "failed to enable clocks\n");
> +               goto err_clk;
> +       }
> +
> +       ret = generic_phy_init(&priv->phy);
> +       if (ret) {
> +               dev_err(dev, "failed to initialize PHY\n");
> +               goto err_phy_init;
> +       }
> +
> +       ret = generic_phy_power_on(&priv->phy);
> +       if (ret) {
> +               dev_err(dev, "failed to power on PHY\n");
> +               goto err_phy_power;
> +       }
> +
> +       imx_pcie_deassert_core_reset(priv);
> +
> +       priv->dw.first_busno = dev_seq(dev);
> +       priv->dw.dev = dev;
> +       pcie_dw_setup_host(&priv->dw);
> +
> +       if (pcie_link_up(priv, LINK_SPEED_GEN_1)) {
> +               printf("PCIE-%d: Link down\n", dev_seq(dev));
> +               ret = -ENODEV;
> +               goto err_link;
> +       }
> +
> +       printf("PCIE-%d: Link up (Gen%d-x%d, Bus%d)\n", dev_seq(dev),
> +              pcie_dw_get_link_speed(&priv->dw),
> +              pcie_dw_get_link_width(&priv->dw),
> +              hose->first_busno);
> +
> +       pcie_dw_prog_outbound_atu_unroll(&priv->dw, PCIE_ATU_REGION_INDEX0,
> +                                        PCIE_ATU_TYPE_MEM,
> +                                        priv->dw.mem.phys_start,
> +                                        priv->dw.mem.bus_start, priv->dw.mem.size);
> +
> +       return 0;
> +
> +err_link:
> +       generic_shutdown_phy(&priv->phy);
> +err_phy_power:
> +       generic_phy_exit(&priv->phy);
> +err_phy_init:
> +       clk_disable_bulk(&priv->clks);
> +err_clk:
> +       imx_pcie_deassert_core_reset(priv);
> +
> +       return ret;
> +}
> +
> +static int pcie_dw_imx_remove(struct udevice *dev)
> +{
> +       struct pcie_dw_imx *priv = dev_get_priv(dev);
> +
> +       generic_shutdown_phy(&priv->phy);
> +       dm_gpio_free(dev, &priv->reset_gpio);
> +       reset_release_all(&priv->apps_reset, 1);
> +       clk_release_bulk(&priv->clks);
> +
> +       return 0;
> +}
> +
> +static int pcie_dw_imx_of_to_plat(struct udevice *dev)
> +{
> +       struct pcie_dw_imx *priv = dev_get_priv(dev);
> +       ofnode gpr;
> +       int ret;
> +
> +       /* Get the controller base address */
> +       priv->dw.dbi_base = (void *)dev_read_addr_name(dev, "dbi");
> +       if ((fdt_addr_t)priv->dw.dbi_base == FDT_ADDR_T_NONE) {
> +               dev_err(dev, "failed to get dbi_base address\n");
> +               return -EINVAL;
> +       }
> +
> +       /* Get the config space base address and size */
> +       priv->dw.cfg_base = (void *)dev_read_addr_size_name(dev, "config",
> +                                                           &priv->dw.cfg_size);
> +       if ((fdt_addr_t)priv->dw.cfg_base == FDT_ADDR_T_NONE) {
> +               dev_err(dev, "failed to get cfg_base address\n");
> +               return -EINVAL;
> +       }
> +
> +       ret = clk_get_bulk(dev, &priv->clks);
> +       if (ret) {
> +               dev_err(dev, "failed to get PCIe clks\n");
> +               return ret;
> +       }
> +
> +       ret = reset_get_by_name(dev, "apps", &priv->apps_reset);
> +       if (ret) {
> +               dev_err(dev,
> +                       "Failed to get PCIe apps reset control\n");
> +               return ret;
> +       }
> +
> +       ret = gpio_request_by_name(dev, "reset-gpio", 0, &priv->reset_gpio,
> +                                  (GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE));
> +       if (ret) {
> +               dev_err(dev, "unable to get reset-gpio\n");
> +               return ret;
> +       }
> +
> +       ret = generic_phy_get_by_name(dev, "pcie-phy", &priv->phy);
> +       if (ret) {
> +               dev_err(dev, "failed to get pcie phy\n");
> +               return ret;
> +       }
> +
> +       gpr = ofnode_by_compatible(ofnode_null(), "fsl,imx8mp-iomuxc-gpr");
> +       if (ofnode_equal(gpr, ofnode_null())) {
> +               dev_err(dev, "unable to find GPR node\n");
> +               return -ENODEV;
> +       }
> +
> +       priv->iomuxc_gpr = syscon_node_to_regmap(gpr);
> +       if (IS_ERR(priv->iomuxc_gpr)) {
> +               dev_err(dev, "unable to find iomuxc registers\n");
> +               return PTR_ERR(priv->iomuxc_gpr);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct dm_pci_ops pcie_dw_imx_ops = {
> +       .read_config    = pcie_dw_read_config,
> +       .write_config   = pcie_dw_write_config,
> +};
> +
> +static const struct udevice_id pcie_dw_imx_ids[] = {
> +       { .compatible = "fsl,imx8mp-pcie" },
> +       { }
> +};
> +
> +U_BOOT_DRIVER(pcie_dw_imx) = {
> +       .name           = "pcie_dw_imx",
> +       .id             = UCLASS_PCI,
> +       .of_match       = pcie_dw_imx_ids,
> +       .ops            = &pcie_dw_imx_ops,
> +       .of_to_plat     = pcie_dw_imx_of_to_plat,
> +       .probe          = pcie_dw_imx_probe,
> +       .remove         = pcie_dw_imx_remove,
> +       .priv_auto      = sizeof(struct pcie_dw_imx),
> +};
> --
> 2.34.1
>
Sumit Garg Feb. 28, 2024, 7 a.m. UTC | #4
On Wed, 28 Feb 2024 at 04:44, Adam Ford <aford173@gmail.com> wrote:
>
> On Mon, Feb 26, 2024 at 2:05 AM Sumit Garg <sumit.garg@linaro.org> wrote:
> >
> > pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
> > tied to quite old port of pcie_designware driver from Linux which
> > suffices only iMX6 specific needs.
> >
> > But currently we have the common DWC specific bits which alligns pretty
> > well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
> > bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
> > add support for other iMX8 variants to this driver.
> >
> > iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
> > can reuse the generic PHY infrastructure to power on PCIe PHY.
> >
> > Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> > ---
> >  drivers/pci/Kconfig       |   8 +
> >  drivers/pci/Makefile      |   1 +
> >  drivers/pci/pcie_dw_imx.c | 314 ++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 323 insertions(+)
> >  create mode 100644 drivers/pci/pcie_dw_imx.c
> >
> > diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> > index 463ec47eb92d..7edbf35004a9 100644
> > --- a/drivers/pci/Kconfig
> > +++ b/drivers/pci/Kconfig
> > @@ -413,4 +413,12 @@ config PCIE_STARFIVE_JH7110
> >           Say Y here if you want to enable PLDA XpressRich PCIe controller
> >           support on StarFive JH7110 SoC.
> >
> > +config PCIE_DW_IMX
> > +       bool "i.MX DW PCIe controller support"
> > +       depends on ARCH_IMX8M
>
> I think this also needs to depend on REGMAP to prevent build errors.
>

Ack, I will add that.

-Sumit

>
> adam
>
> > +       select PCIE_DW_COMMON
> > +       help
> > +         Say Y here if you want to enable DW PCIe controller support on
> > +         iMX SoCs.
> > +
> >  endif
> > diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> > index 72ef8b4bc772..2927c519129b 100644
> > --- a/drivers/pci/Makefile
> > +++ b/drivers/pci/Makefile
> > @@ -53,3 +53,4 @@ obj-$(CONFIG_PCIE_UNIPHIER) += pcie_uniphier.o
> >  obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
> >  obj-$(CONFIG_PCIE_PLDA_COMMON) += pcie_plda_common.o
> >  obj-$(CONFIG_PCIE_STARFIVE_JH7110) += pcie_starfive_jh7110.o
> > +obj-$(CONFIG_PCIE_DW_IMX) += pcie_dw_imx.o
> > diff --git a/drivers/pci/pcie_dw_imx.c b/drivers/pci/pcie_dw_imx.c
> > new file mode 100644
> > index 000000000000..7856823c9188
> > --- /dev/null
> > +++ b/drivers/pci/pcie_dw_imx.c
> > @@ -0,0 +1,314 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2024 Linaro Ltd.
> > + *
> > + * Author: Sumit Garg <sumit.garg@linaro.org>
> > + */
> > +
> > +#include <asm/io.h>
> > +#include <asm-generic/gpio.h>
> > +#include <clk.h>
> > +#include <dm.h>
> > +#include <dm/device_compat.h>
> > +#include <generic-phy.h>
> > +#include <linux/bitops.h>
> > +#include <linux/delay.h>
> > +#include <linux/err.h>
> > +#include <linux/iopoll.h>
> > +#include <log.h>
> > +#include <pci.h>
> > +#include <regmap.h>
> > +#include <reset.h>
> > +#include <syscon.h>
> > +#include <time.h>
> > +
> > +#include "pcie_dw_common.h"
> > +
> > +#define PCIE_LINK_CAPABILITY           0x7c
> > +#define TARGET_LINK_SPEED_MASK         0xf
> > +#define LINK_SPEED_GEN_1               0x1
> > +#define LINK_SPEED_GEN_2               0x2
> > +#define LINK_SPEED_GEN_3               0x3
> > +
> > +#define PCIE_MISC_CONTROL_1_OFF                0x8bc
> > +#define PCIE_DBI_RO_WR_EN              BIT(0)
> > +
> > +#define PCIE_PORT_DEBUG0                       0x728
> > +#define PCIE_PORT_DEBUG1                       0x72c
> > +#define PCIE_PORT_DEBUG1_LINK_UP               BIT(4)
> > +#define PCIE_PORT_DEBUG1_LINK_IN_TRAINING      BIT(29)
> > +
> > +#define PCIE_LINK_UP_TIMEOUT_MS                100
> > +
> > +#define IOMUXC_GPR14_OFFSET                    0x38
> > +#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN     BIT(10)
> > +#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE                BIT(11)
> > +
> > +struct pcie_dw_imx {
> > +       /* Must be first member of the struct */
> > +       struct pcie_dw                  dw;
> > +       struct regmap                   *iomuxc_gpr;
> > +       struct clk_bulk                 clks;
> > +       struct gpio_desc                reset_gpio;
> > +       struct reset_ctl                apps_reset;
> > +       struct phy                      phy;
> > +};
> > +
> > +static void pcie_dw_configure(struct pcie_dw_imx *priv, u32 cap_speed)
> > +{
> > +       dw_pcie_dbi_write_enable(&priv->dw, true);
> > +
> > +       clrsetbits_le32(priv->dw.dbi_base + PCIE_LINK_CAPABILITY,
> > +                       TARGET_LINK_SPEED_MASK, cap_speed);
> > +
> > +       dw_pcie_dbi_write_enable(&priv->dw, false);
> > +}
> > +
> > +static void imx_pcie_ltssm_enable(struct pcie_dw_imx *priv)
> > +{
> > +       reset_deassert(&priv->apps_reset);
> > +}
> > +
> > +static void imx_pcie_ltssm_disable(struct pcie_dw_imx *priv)
> > +{
> > +       reset_assert(&priv->apps_reset);
> > +}
> > +
> > +static bool is_link_up(u32 val)
> > +{
> > +       return ((val & PCIE_PORT_DEBUG1_LINK_UP) &&
> > +               (!(val & PCIE_PORT_DEBUG1_LINK_IN_TRAINING)));
> > +}
> > +
> > +static int wait_link_up(struct pcie_dw_imx *priv)
> > +{
> > +       u32 val;
> > +
> > +       return readl_poll_sleep_timeout(priv->dw.dbi_base + PCIE_PORT_DEBUG1,
> > +                                       val, is_link_up(val), 10000, 100000);
> > +}
> > +
> > +static int pcie_link_up(struct pcie_dw_imx *priv, u32 cap_speed)
> > +{
> > +       int ret;
> > +
> > +       /* DW pre link configurations */
> > +       pcie_dw_configure(priv, cap_speed);
> > +
> > +       /* Initiate link training */
> > +       imx_pcie_ltssm_enable(priv);
> > +
> > +       /* Check that link was established */
> > +       ret = wait_link_up(priv);
> > +       if (ret)
> > +               imx_pcie_ltssm_disable(priv);
> > +
> > +       return ret;
> > +}
> > +
> > +static int imx_pcie_assert_core_reset(struct pcie_dw_imx *priv)
> > +{
> > +       if (dm_gpio_is_valid(&priv->reset_gpio)) {
> > +               dm_gpio_set_value(&priv->reset_gpio, 1);
> > +               mdelay(20);
> > +       }
> > +
> > +       return reset_assert(&priv->apps_reset);
> > +}
> > +
> > +static int imx_pcie_clk_enable(struct pcie_dw_imx *priv)
> > +{
> > +       int ret;
> > +
> > +       ret = clk_enable_bulk(&priv->clks);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /*
> > +        * Set the over ride low and enabled make sure that
> > +        * REF_CLK is turned on.
> > +        */
> > +       regmap_update_bits(priv->iomuxc_gpr, IOMUXC_GPR14_OFFSET,
> > +                          IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE, 0);
> > +       regmap_update_bits(priv->iomuxc_gpr, IOMUXC_GPR14_OFFSET,
> > +                          IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
> > +                          IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
> > +
> > +       /* allow the clocks to stabilize */
> > +       udelay(500);
> > +
> > +       return 0;
> > +}
> > +
> > +static void imx_pcie_deassert_core_reset(struct pcie_dw_imx *priv)
> > +{
> > +       if (!dm_gpio_is_valid(&priv->reset_gpio))
> > +               return;
> > +
> > +       mdelay(100);
> > +       dm_gpio_set_value(&priv->reset_gpio, 0);
> > +       /* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
> > +       mdelay(100);
> > +}
> > +
> > +static int pcie_dw_imx_probe(struct udevice *dev)
> > +{
> > +       struct pcie_dw_imx *priv = dev_get_priv(dev);
> > +       struct udevice *ctlr = pci_get_controller(dev);
> > +       struct pci_controller *hose = dev_get_uclass_priv(ctlr);
> > +       int ret;
> > +
> > +       ret = imx_pcie_assert_core_reset(priv);
> > +       if (ret) {
> > +               dev_err(dev, "failed to assert core reset\n");
> > +               return ret;
> > +       }
> > +
> > +       ret = imx_pcie_clk_enable(priv);
> > +       if (ret) {
> > +               dev_err(dev, "failed to enable clocks\n");
> > +               goto err_clk;
> > +       }
> > +
> > +       ret = generic_phy_init(&priv->phy);
> > +       if (ret) {
> > +               dev_err(dev, "failed to initialize PHY\n");
> > +               goto err_phy_init;
> > +       }
> > +
> > +       ret = generic_phy_power_on(&priv->phy);
> > +       if (ret) {
> > +               dev_err(dev, "failed to power on PHY\n");
> > +               goto err_phy_power;
> > +       }
> > +
> > +       imx_pcie_deassert_core_reset(priv);
> > +
> > +       priv->dw.first_busno = dev_seq(dev);
> > +       priv->dw.dev = dev;
> > +       pcie_dw_setup_host(&priv->dw);
> > +
> > +       if (pcie_link_up(priv, LINK_SPEED_GEN_1)) {
> > +               printf("PCIE-%d: Link down\n", dev_seq(dev));
> > +               ret = -ENODEV;
> > +               goto err_link;
> > +       }
> > +
> > +       printf("PCIE-%d: Link up (Gen%d-x%d, Bus%d)\n", dev_seq(dev),
> > +              pcie_dw_get_link_speed(&priv->dw),
> > +              pcie_dw_get_link_width(&priv->dw),
> > +              hose->first_busno);
> > +
> > +       pcie_dw_prog_outbound_atu_unroll(&priv->dw, PCIE_ATU_REGION_INDEX0,
> > +                                        PCIE_ATU_TYPE_MEM,
> > +                                        priv->dw.mem.phys_start,
> > +                                        priv->dw.mem.bus_start, priv->dw.mem.size);
> > +
> > +       return 0;
> > +
> > +err_link:
> > +       generic_shutdown_phy(&priv->phy);
> > +err_phy_power:
> > +       generic_phy_exit(&priv->phy);
> > +err_phy_init:
> > +       clk_disable_bulk(&priv->clks);
> > +err_clk:
> > +       imx_pcie_deassert_core_reset(priv);
> > +
> > +       return ret;
> > +}
> > +
> > +static int pcie_dw_imx_remove(struct udevice *dev)
> > +{
> > +       struct pcie_dw_imx *priv = dev_get_priv(dev);
> > +
> > +       generic_shutdown_phy(&priv->phy);
> > +       dm_gpio_free(dev, &priv->reset_gpio);
> > +       reset_release_all(&priv->apps_reset, 1);
> > +       clk_release_bulk(&priv->clks);
> > +
> > +       return 0;
> > +}
> > +
> > +static int pcie_dw_imx_of_to_plat(struct udevice *dev)
> > +{
> > +       struct pcie_dw_imx *priv = dev_get_priv(dev);
> > +       ofnode gpr;
> > +       int ret;
> > +
> > +       /* Get the controller base address */
> > +       priv->dw.dbi_base = (void *)dev_read_addr_name(dev, "dbi");
> > +       if ((fdt_addr_t)priv->dw.dbi_base == FDT_ADDR_T_NONE) {
> > +               dev_err(dev, "failed to get dbi_base address\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       /* Get the config space base address and size */
> > +       priv->dw.cfg_base = (void *)dev_read_addr_size_name(dev, "config",
> > +                                                           &priv->dw.cfg_size);
> > +       if ((fdt_addr_t)priv->dw.cfg_base == FDT_ADDR_T_NONE) {
> > +               dev_err(dev, "failed to get cfg_base address\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       ret = clk_get_bulk(dev, &priv->clks);
> > +       if (ret) {
> > +               dev_err(dev, "failed to get PCIe clks\n");
> > +               return ret;
> > +       }
> > +
> > +       ret = reset_get_by_name(dev, "apps", &priv->apps_reset);
> > +       if (ret) {
> > +               dev_err(dev,
> > +                       "Failed to get PCIe apps reset control\n");
> > +               return ret;
> > +       }
> > +
> > +       ret = gpio_request_by_name(dev, "reset-gpio", 0, &priv->reset_gpio,
> > +                                  (GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE));
> > +       if (ret) {
> > +               dev_err(dev, "unable to get reset-gpio\n");
> > +               return ret;
> > +       }
> > +
> > +       ret = generic_phy_get_by_name(dev, "pcie-phy", &priv->phy);
> > +       if (ret) {
> > +               dev_err(dev, "failed to get pcie phy\n");
> > +               return ret;
> > +       }
> > +
> > +       gpr = ofnode_by_compatible(ofnode_null(), "fsl,imx8mp-iomuxc-gpr");
> > +       if (ofnode_equal(gpr, ofnode_null())) {
> > +               dev_err(dev, "unable to find GPR node\n");
> > +               return -ENODEV;
> > +       }
> > +
> > +       priv->iomuxc_gpr = syscon_node_to_regmap(gpr);
> > +       if (IS_ERR(priv->iomuxc_gpr)) {
> > +               dev_err(dev, "unable to find iomuxc registers\n");
> > +               return PTR_ERR(priv->iomuxc_gpr);
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct dm_pci_ops pcie_dw_imx_ops = {
> > +       .read_config    = pcie_dw_read_config,
> > +       .write_config   = pcie_dw_write_config,
> > +};
> > +
> > +static const struct udevice_id pcie_dw_imx_ids[] = {
> > +       { .compatible = "fsl,imx8mp-pcie" },
> > +       { }
> > +};
> > +
> > +U_BOOT_DRIVER(pcie_dw_imx) = {
> > +       .name           = "pcie_dw_imx",
> > +       .id             = UCLASS_PCI,
> > +       .of_match       = pcie_dw_imx_ids,
> > +       .ops            = &pcie_dw_imx_ops,
> > +       .of_to_plat     = pcie_dw_imx_of_to_plat,
> > +       .probe          = pcie_dw_imx_probe,
> > +       .remove         = pcie_dw_imx_remove,
> > +       .priv_auto      = sizeof(struct pcie_dw_imx),
> > +};
> > --
> > 2.34.1
> >
Tim Harvey Feb. 28, 2024, 4:36 p.m. UTC | #5
On Tue, Feb 27, 2024 at 3:19 PM Adam Ford <aford173@gmail.com> wrote:
>
> On Mon, Feb 26, 2024 at 2:05 AM Sumit Garg <sumit.garg@linaro.org> wrote:
> >
> > pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
> > tied to quite old port of pcie_designware driver from Linux which
> > suffices only iMX6 specific needs.
> >
> > But currently we have the common DWC specific bits which alligns pretty
> > well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
> > bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
> > add support for other iMX8 variants to this driver.
> >
> > iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
> > can reuse the generic PHY infrastructure to power on PCIe PHY.
> >
> > Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> > ---
> >  drivers/pci/Kconfig       |   8 +
> >  drivers/pci/Makefile      |   1 +
> >  drivers/pci/pcie_dw_imx.c | 314 ++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 323 insertions(+)
> >  create mode 100644 drivers/pci/pcie_dw_imx.c
> >
> > diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> > index 463ec47eb92d..7edbf35004a9 100644
> > --- a/drivers/pci/Kconfig
> > +++ b/drivers/pci/Kconfig
> > @@ -413,4 +413,12 @@ config PCIE_STARFIVE_JH7110
> >           Say Y here if you want to enable PLDA XpressRich PCIe controller
> >           support on StarFive JH7110 SoC.
> >
> > +config PCIE_DW_IMX
> > +       bool "i.MX DW PCIe controller support"
> > +       depends on ARCH_IMX8M
>
> I think this also needs to depend on REGMAP to prevent build errors.
>

Sumit,

both REGMAP and SYSCON are needed to build.

Best Regards,

Tim
Sumit Garg Feb. 29, 2024, 5:29 a.m. UTC | #6
On Wed, 28 Feb 2024 at 22:07, Tim Harvey <tharvey@gateworks.com> wrote:
>
> On Tue, Feb 27, 2024 at 3:19 PM Adam Ford <aford173@gmail.com> wrote:
> >
> > On Mon, Feb 26, 2024 at 2:05 AM Sumit Garg <sumit.garg@linaro.org> wrote:
> > >
> > > pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
> > > tied to quite old port of pcie_designware driver from Linux which
> > > suffices only iMX6 specific needs.
> > >
> > > But currently we have the common DWC specific bits which alligns pretty
> > > well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
> > > bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
> > > add support for other iMX8 variants to this driver.
> > >
> > > iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
> > > can reuse the generic PHY infrastructure to power on PCIe PHY.
> > >
> > > Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> > > ---
> > >  drivers/pci/Kconfig       |   8 +
> > >  drivers/pci/Makefile      |   1 +
> > >  drivers/pci/pcie_dw_imx.c | 314 ++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 323 insertions(+)
> > >  create mode 100644 drivers/pci/pcie_dw_imx.c
> > >
> > > diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> > > index 463ec47eb92d..7edbf35004a9 100644
> > > --- a/drivers/pci/Kconfig
> > > +++ b/drivers/pci/Kconfig
> > > @@ -413,4 +413,12 @@ config PCIE_STARFIVE_JH7110
> > >           Say Y here if you want to enable PLDA XpressRich PCIe controller
> > >           support on StarFive JH7110 SoC.
> > >
> > > +config PCIE_DW_IMX
> > > +       bool "i.MX DW PCIe controller support"
> > > +       depends on ARCH_IMX8M
> >
> > I think this also needs to depend on REGMAP to prevent build errors.
> >
>
> Sumit,
>
> both REGMAP and SYSCON are needed to build.
>

Ack.

-Sumit
diff mbox series

Patch

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 463ec47eb92d..7edbf35004a9 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -413,4 +413,12 @@  config PCIE_STARFIVE_JH7110
 	  Say Y here if you want to enable PLDA XpressRich PCIe controller
 	  support on StarFive JH7110 SoC.
 
+config PCIE_DW_IMX
+	bool "i.MX DW PCIe controller support"
+	depends on ARCH_IMX8M
+	select PCIE_DW_COMMON
+	help
+	  Say Y here if you want to enable DW PCIe controller support on
+	  iMX SoCs.
+
 endif
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 72ef8b4bc772..2927c519129b 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -53,3 +53,4 @@  obj-$(CONFIG_PCIE_UNIPHIER) += pcie_uniphier.o
 obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
 obj-$(CONFIG_PCIE_PLDA_COMMON) += pcie_plda_common.o
 obj-$(CONFIG_PCIE_STARFIVE_JH7110) += pcie_starfive_jh7110.o
+obj-$(CONFIG_PCIE_DW_IMX) += pcie_dw_imx.o
diff --git a/drivers/pci/pcie_dw_imx.c b/drivers/pci/pcie_dw_imx.c
new file mode 100644
index 000000000000..7856823c9188
--- /dev/null
+++ b/drivers/pci/pcie_dw_imx.c
@@ -0,0 +1,314 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2024 Linaro Ltd.
+ *
+ * Author: Sumit Garg <sumit.garg@linaro.org>
+ */
+
+#include <asm/io.h>
+#include <asm-generic/gpio.h>
+#include <clk.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <generic-phy.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <log.h>
+#include <pci.h>
+#include <regmap.h>
+#include <reset.h>
+#include <syscon.h>
+#include <time.h>
+
+#include "pcie_dw_common.h"
+
+#define PCIE_LINK_CAPABILITY		0x7c
+#define TARGET_LINK_SPEED_MASK		0xf
+#define LINK_SPEED_GEN_1		0x1
+#define LINK_SPEED_GEN_2		0x2
+#define LINK_SPEED_GEN_3		0x3
+
+#define PCIE_MISC_CONTROL_1_OFF		0x8bc
+#define PCIE_DBI_RO_WR_EN		BIT(0)
+
+#define PCIE_PORT_DEBUG0			0x728
+#define PCIE_PORT_DEBUG1			0x72c
+#define PCIE_PORT_DEBUG1_LINK_UP		BIT(4)
+#define PCIE_PORT_DEBUG1_LINK_IN_TRAINING	BIT(29)
+
+#define PCIE_LINK_UP_TIMEOUT_MS		100
+
+#define IOMUXC_GPR14_OFFSET			0x38
+#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN	BIT(10)
+#define IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE		BIT(11)
+
+struct pcie_dw_imx {
+	/* Must be first member of the struct */
+	struct pcie_dw			dw;
+	struct regmap			*iomuxc_gpr;
+	struct clk_bulk			clks;
+	struct gpio_desc		reset_gpio;
+	struct reset_ctl		apps_reset;
+	struct phy			phy;
+};
+
+static void pcie_dw_configure(struct pcie_dw_imx *priv, u32 cap_speed)
+{
+	dw_pcie_dbi_write_enable(&priv->dw, true);
+
+	clrsetbits_le32(priv->dw.dbi_base + PCIE_LINK_CAPABILITY,
+			TARGET_LINK_SPEED_MASK, cap_speed);
+
+	dw_pcie_dbi_write_enable(&priv->dw, false);
+}
+
+static void imx_pcie_ltssm_enable(struct pcie_dw_imx *priv)
+{
+	reset_deassert(&priv->apps_reset);
+}
+
+static void imx_pcie_ltssm_disable(struct pcie_dw_imx *priv)
+{
+	reset_assert(&priv->apps_reset);
+}
+
+static bool is_link_up(u32 val)
+{
+	return ((val & PCIE_PORT_DEBUG1_LINK_UP) &&
+		(!(val & PCIE_PORT_DEBUG1_LINK_IN_TRAINING)));
+}
+
+static int wait_link_up(struct pcie_dw_imx *priv)
+{
+	u32 val;
+
+	return readl_poll_sleep_timeout(priv->dw.dbi_base + PCIE_PORT_DEBUG1,
+					val, is_link_up(val), 10000, 100000);
+}
+
+static int pcie_link_up(struct pcie_dw_imx *priv, u32 cap_speed)
+{
+	int ret;
+
+	/* DW pre link configurations */
+	pcie_dw_configure(priv, cap_speed);
+
+	/* Initiate link training */
+	imx_pcie_ltssm_enable(priv);
+
+	/* Check that link was established */
+	ret = wait_link_up(priv);
+	if (ret)
+		imx_pcie_ltssm_disable(priv);
+
+	return ret;
+}
+
+static int imx_pcie_assert_core_reset(struct pcie_dw_imx *priv)
+{
+	if (dm_gpio_is_valid(&priv->reset_gpio)) {
+		dm_gpio_set_value(&priv->reset_gpio, 1);
+		mdelay(20);
+	}
+
+	return reset_assert(&priv->apps_reset);
+}
+
+static int imx_pcie_clk_enable(struct pcie_dw_imx *priv)
+{
+	int ret;
+
+	ret = clk_enable_bulk(&priv->clks);
+	if (ret)
+		return ret;
+
+	/*
+	 * Set the over ride low and enabled make sure that
+	 * REF_CLK is turned on.
+	 */
+	regmap_update_bits(priv->iomuxc_gpr, IOMUXC_GPR14_OFFSET,
+			   IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE, 0);
+	regmap_update_bits(priv->iomuxc_gpr, IOMUXC_GPR14_OFFSET,
+			   IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN,
+			   IMX8M_GPR_PCIE_CLK_REQ_OVERRIDE_EN);
+
+	/* allow the clocks to stabilize */
+	udelay(500);
+
+	return 0;
+}
+
+static void imx_pcie_deassert_core_reset(struct pcie_dw_imx *priv)
+{
+	if (!dm_gpio_is_valid(&priv->reset_gpio))
+		return;
+
+	mdelay(100);
+	dm_gpio_set_value(&priv->reset_gpio, 0);
+	/* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
+	mdelay(100);
+}
+
+static int pcie_dw_imx_probe(struct udevice *dev)
+{
+	struct pcie_dw_imx *priv = dev_get_priv(dev);
+	struct udevice *ctlr = pci_get_controller(dev);
+	struct pci_controller *hose = dev_get_uclass_priv(ctlr);
+	int ret;
+
+	ret = imx_pcie_assert_core_reset(priv);
+	if (ret) {
+		dev_err(dev, "failed to assert core reset\n");
+		return ret;
+	}
+
+	ret = imx_pcie_clk_enable(priv);
+	if (ret) {
+		dev_err(dev, "failed to enable clocks\n");
+		goto err_clk;
+	}
+
+	ret = generic_phy_init(&priv->phy);
+	if (ret) {
+		dev_err(dev, "failed to initialize PHY\n");
+		goto err_phy_init;
+	}
+
+	ret = generic_phy_power_on(&priv->phy);
+	if (ret) {
+		dev_err(dev, "failed to power on PHY\n");
+		goto err_phy_power;
+	}
+
+	imx_pcie_deassert_core_reset(priv);
+
+	priv->dw.first_busno = dev_seq(dev);
+	priv->dw.dev = dev;
+	pcie_dw_setup_host(&priv->dw);
+
+	if (pcie_link_up(priv, LINK_SPEED_GEN_1)) {
+		printf("PCIE-%d: Link down\n", dev_seq(dev));
+		ret = -ENODEV;
+		goto err_link;
+	}
+
+	printf("PCIE-%d: Link up (Gen%d-x%d, Bus%d)\n", dev_seq(dev),
+	       pcie_dw_get_link_speed(&priv->dw),
+	       pcie_dw_get_link_width(&priv->dw),
+	       hose->first_busno);
+
+	pcie_dw_prog_outbound_atu_unroll(&priv->dw, PCIE_ATU_REGION_INDEX0,
+					 PCIE_ATU_TYPE_MEM,
+					 priv->dw.mem.phys_start,
+					 priv->dw.mem.bus_start, priv->dw.mem.size);
+
+	return 0;
+
+err_link:
+	generic_shutdown_phy(&priv->phy);
+err_phy_power:
+	generic_phy_exit(&priv->phy);
+err_phy_init:
+	clk_disable_bulk(&priv->clks);
+err_clk:
+	imx_pcie_deassert_core_reset(priv);
+
+	return ret;
+}
+
+static int pcie_dw_imx_remove(struct udevice *dev)
+{
+	struct pcie_dw_imx *priv = dev_get_priv(dev);
+
+	generic_shutdown_phy(&priv->phy);
+	dm_gpio_free(dev, &priv->reset_gpio);
+	reset_release_all(&priv->apps_reset, 1);
+	clk_release_bulk(&priv->clks);
+
+	return 0;
+}
+
+static int pcie_dw_imx_of_to_plat(struct udevice *dev)
+{
+	struct pcie_dw_imx *priv = dev_get_priv(dev);
+	ofnode gpr;
+	int ret;
+
+	/* Get the controller base address */
+	priv->dw.dbi_base = (void *)dev_read_addr_name(dev, "dbi");
+	if ((fdt_addr_t)priv->dw.dbi_base == FDT_ADDR_T_NONE) {
+		dev_err(dev, "failed to get dbi_base address\n");
+		return -EINVAL;
+	}
+
+	/* Get the config space base address and size */
+	priv->dw.cfg_base = (void *)dev_read_addr_size_name(dev, "config",
+							    &priv->dw.cfg_size);
+	if ((fdt_addr_t)priv->dw.cfg_base == FDT_ADDR_T_NONE) {
+		dev_err(dev, "failed to get cfg_base address\n");
+		return -EINVAL;
+	}
+
+	ret = clk_get_bulk(dev, &priv->clks);
+	if (ret) {
+		dev_err(dev, "failed to get PCIe clks\n");
+		return ret;
+	}
+
+	ret = reset_get_by_name(dev, "apps", &priv->apps_reset);
+	if (ret) {
+		dev_err(dev,
+			"Failed to get PCIe apps reset control\n");
+		return ret;
+	}
+
+	ret = gpio_request_by_name(dev, "reset-gpio", 0, &priv->reset_gpio,
+				   (GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE));
+	if (ret) {
+		dev_err(dev, "unable to get reset-gpio\n");
+		return ret;
+	}
+
+	ret = generic_phy_get_by_name(dev, "pcie-phy", &priv->phy);
+	if (ret) {
+		dev_err(dev, "failed to get pcie phy\n");
+		return ret;
+	}
+
+	gpr = ofnode_by_compatible(ofnode_null(), "fsl,imx8mp-iomuxc-gpr");
+	if (ofnode_equal(gpr, ofnode_null())) {
+		dev_err(dev, "unable to find GPR node\n");
+		return -ENODEV;
+	}
+
+	priv->iomuxc_gpr = syscon_node_to_regmap(gpr);
+	if (IS_ERR(priv->iomuxc_gpr)) {
+		dev_err(dev, "unable to find iomuxc registers\n");
+		return PTR_ERR(priv->iomuxc_gpr);
+	}
+
+	return 0;
+}
+
+static const struct dm_pci_ops pcie_dw_imx_ops = {
+	.read_config	= pcie_dw_read_config,
+	.write_config	= pcie_dw_write_config,
+};
+
+static const struct udevice_id pcie_dw_imx_ids[] = {
+	{ .compatible = "fsl,imx8mp-pcie" },
+	{ }
+};
+
+U_BOOT_DRIVER(pcie_dw_imx) = {
+	.name		= "pcie_dw_imx",
+	.id		= UCLASS_PCI,
+	.of_match	= pcie_dw_imx_ids,
+	.ops		= &pcie_dw_imx_ops,
+	.of_to_plat	= pcie_dw_imx_of_to_plat,
+	.probe		= pcie_dw_imx_probe,
+	.remove		= pcie_dw_imx_remove,
+	.priv_auto	= sizeof(struct pcie_dw_imx),
+};