Re: [PATCH v4 2/3] PCI: dwc: Add Qualcomm PCIe Endpoint controller driver

[Rob Herring <robh@kernel.org>]

(). On Thu, Jun 24, 2021 at 1:26 AM Manivannan Sadhasivam
<manivannan.sadhasivam@linaro.org> wrote:
>
> Add driver support for Qualcomm PCIe Endpoint controller driver based on
> the Designware core with added Qualcomm specific wrapper around the
> core. The driver support is very basic such that it supports only
> enumeration, PCIe read/write, and MSI. There is no ASPM and PM support
> for now but these will be added later.
>
> The driver is capable of using the PERST# and WAKE# side-band GPIOs for
> operation and written on top of the DWC PCI framework.
>
> Co-developed-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
> Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
> [mani: restructured the driver and fixed several bugs for upstream]
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/controller/dwc/Kconfig        |  10 +
>  drivers/pci/controller/dwc/Makefile       |   1 +
>  drivers/pci/controller/dwc/pcie-qcom-ep.c | 751 ++++++++++++++++++++++
>  3 files changed, 762 insertions(+)
>  create mode 100644 drivers/pci/controller/dwc/pcie-qcom-ep.c
>
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index 423d35872ce4..eedfe57dadad 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -180,6 +180,16 @@ config PCIE_QCOM
>           PCIe controller uses the DesignWare core plus Qualcomm-specific
>           hardware wrappers.
>
> +config PCIE_QCOM_EP
> +       tristate "Qualcomm PCIe controller - Endpoint mode"
> +       depends on OF && (ARCH_QCOM || COMPILE_TEST)
> +       depends on PCI_ENDPOINT
> +       select PCIE_DW_EP
> +       help
> +         Say Y here to enable support for the PCIe controllers on Qualcomm SoCs
> +         to work in endpoint mode. The PCIe controller uses the DesignWare core
> +         plus Qualcomm-specific hardware wrappers.
> +
>  config PCIE_ARMADA_8K
>         bool "Marvell Armada-8K PCIe controller"
>         depends on ARCH_MVEBU || COMPILE_TEST
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index eca805c1a023..abb27642d46b 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone.o
>  obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
>  obj-$(CONFIG_PCI_LAYERSCAPE_EP) += pci-layerscape-ep.o
>  obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
> +obj-$(CONFIG_PCIE_QCOM_EP) += pcie-qcom-ep.o
>  obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
>  obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
>  obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> new file mode 100644
> index 000000000000..d824eb2e57d9
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> @@ -0,0 +1,751 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Qualcomm PCIe Endpoint controller driver
> + *
> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
> + * Author: Siddartha Mohanadoss <smohanad@codeaurora.org
> + *
> + * Copyright (c) 2021, Linaro Ltd.
> + * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +
> +#include "pcie-designware.h"
> +
> +/* PARF registers */
> +#define PARF_SYS_CTRL                          0x00
> +#define PARF_DB_CTRL                           0x10
> +#define PARF_PM_CTRL                           0x20
> +#define PARF_MHI_BASE_ADDR_LOWER               0x178
> +#define PARF_MHI_BASE_ADDR_UPPER               0x17c
> +#define PARF_DEBUG_INT_EN                      0x190
> +#define PARF_AXI_MSTR_RD_HALT_NO_WRITES                0x1a4
> +#define PARF_AXI_MSTR_WR_ADDR_HALT             0x1a8
> +#define PARF_Q2A_FLUSH                         0x1aC
> +#define PARF_LTSSM                             0x1b0
> +#define PARF_CFG_BITS                          0x210
> +#define PARF_INT_ALL_STATUS                    0x224
> +#define PARF_INT_ALL_CLEAR                     0x228
> +#define PARF_INT_ALL_MASK                      0x22c
> +#define PARF_SLV_ADDR_MSB_CTRL                 0x2c0
> +#define PARF_DBI_BASE_ADDR                     0x350
> +#define PARF_DBI_BASE_ADDR_HI                  0x354
> +#define PARF_SLV_ADDR_SPACE_SIZE               0x358
> +#define PARF_SLV_ADDR_SPACE_SIZE_HI            0x35c
> +#define PARF_ATU_BASE_ADDR                     0x634
> +#define PARF_ATU_BASE_ADDR_HI                  0x638
> +#define PARF_SRIS_MODE                         0x644
> +#define PARF_DEVICE_TYPE                       0x1000
> +#define PARF_BDF_TO_SID_CFG                    0x2c00

A bunch of these defines are already in pcie-qcom.c. Make a header for
the registers and common bits.

> +
> +/* ELBI registers */
> +#define ELBI_SYS_STTS                          0x08
> +
> +/* DBI registers */
> +#define DBI_CAP_ID_NXT_PTR                     0x40
> +#define DBI_CON_STATUS                         0x44
> +#define DBI_DEVICE_CAPABILITIES                        0x74
> +#define DBI_LINK_CAPABILITIES                  0x7c
> +#define DBI_LINK_CONTROL2_LINK_STATUS2         0xa0
> +#define DBI_L1SUB_CAPABILITY                   0x234

These are all standard PCIe config space registers. Use standard
defines and the offsets are discoverable.

> +#define DBI_ACK_F_ASPM_CTRL                    0x70c
> +#define DBI_GEN3_RELATED_OFF                   0x890
> +#define DBI_AUX_CLK_FREQ                       0xb40
> +
> +#define DBI_L0S_ACCPT_LATENCY_MASK             GENMASK(8, 6)
> +#define DBI_L1_ACCPT_LATENCY_MASK              GENMASK(11, 9)
> +#define DBI_L0S_EXIT_LATENCY_MASK              GENMASK(14, 12)
> +#define DBI_L1_EXIT_LATENCY_MASK               GENMASK(17, 15)
> +#define DBI_ACK_N_FTS_MASK                     GENMASK(15, 8)

Standard DWC DBI registers. Use defines in pcie-designware.h and
really any code touching these registers belongs in the common DWC
code.

> +
> +#define XMLH_LINK_UP                           0x400
> +#define CORE_RESET_TIME_US_MIN                 1000
> +#define CORE_RESET_TIME_US_MAX                 1005
> +#define WAKE_DELAY_US                          2000 /* 2 ms */
> +
> +#define to_pcie_ep(x)                          dev_get_drvdata((x)->dev)
> +
> +enum qcom_pcie_ep_link_status {
> +       QCOM_PCIE_EP_LINK_DISABLED,
> +       QCOM_PCIE_EP_LINK_ENABLED,
> +       QCOM_PCIE_EP_LINK_UP,
> +       QCOM_PCIE_EP_LINK_DOWN,
> +};
> +
> +enum qcom_pcie_ep_irq {
> +       QCOM_PCIE_EP_INT_RESERVED,
> +       QCOM_PCIE_EP_INT_LINK_DOWN,
> +       QCOM_PCIE_EP_INT_BME,
> +       QCOM_PCIE_EP_INT_PM_TURNOFF,
> +       QCOM_PCIE_EP_INT_DEBUG,
> +       QCOM_PCIE_EP_INT_LTR,
> +       QCOM_PCIE_EP_INT_MHI_Q6,
> +       QCOM_PCIE_EP_INT_MHI_A7,
> +       QCOM_PCIE_EP_INT_DSTATE_CHANGE,
> +       QCOM_PCIE_EP_INT_L1SUB_TIMEOUT,
> +       QCOM_PCIE_EP_INT_MMIO_WRITE,
> +       QCOM_PCIE_EP_INT_CFG_WRITE,
> +       QCOM_PCIE_EP_INT_BRIDGE_FLUSH_N,
> +       QCOM_PCIE_EP_INT_LINK_UP,
> +       QCOM_PCIE_EP_INT_AER_LEGACY,
> +       QCOM_PCIE_EP_INT_PLS_ERR,
> +       QCOM_PCIE_EP_INT_PME_LEGACY,
> +       QCOM_PCIE_EP_INT_PLS_PME,
> +       QCOM_PCIE_EP_INT_MAX,
> +};
> +
> +static struct clk_bulk_data qcom_pcie_ep_clks[] = {
> +       { .id = "cfg" },
> +       { .id = "aux" },
> +       { .id = "bus_master" },
> +       { .id = "bus_slave" },
> +       { .id = "ref" },
> +       { .id = "sleep" },
> +       { .id = "slave_q2a" },
> +};
> +
> +struct qcom_pcie_ep {
> +       struct dw_pcie pci;
> +
> +       void __iomem *parf;
> +       void __iomem *elbi;
> +       void __iomem *mmio;
> +       struct regmap *perst_map;
> +
> +       struct reset_control *core_reset;
> +       struct gpio_desc *reset;
> +       struct gpio_desc *wake;
> +       struct phy *phy;
> +
> +       resource_size_t dbi_phys;
> +       resource_size_t atu_phys;

These 2 are never used.

> +       resource_size_t mmio_phys;
> +       u32 mmio_size;

'mmio' is a horrible name. It's all MMIO. Is this 'addr_space' used by
other EP drivers?

Just save a pointer to the resource if you need these. Or retrieve the
resource in the one place you need it.

> +       u32 perst_en;
> +       u32 perst_sep_en;
> +
> +       enum qcom_pcie_ep_link_status link_status;
> +       int global_irq;
> +       int perst_irq;
> +};
> +
> +static void qcom_pcie_ep_enable_ltssm(struct qcom_pcie_ep *pcie_ep)
> +{
> +       u32 reg;
> +
> +       reg = readl(pcie_ep->parf + PARF_LTSSM);
> +       reg |= BIT(8);
> +       writel(reg, pcie_ep->parf + PARF_LTSSM);
> +}

Same function as qcom_pcie_2_3_2_ltssm_enable().


> +
> +static int qcom_pcie_ep_core_reset(struct qcom_pcie_ep *pcie_ep)
> +{
> +       struct dw_pcie *pci = &pcie_ep->pci;
> +       struct device *dev = pci->dev;
> +       int ret;
> +
> +       ret = reset_control_assert(pcie_ep->core_reset);
> +       if (ret) {
> +               dev_err(dev, "Cannot assert core reset\n");
> +               return ret;
> +       }
> +
> +       usleep_range(CORE_RESET_TIME_US_MIN, CORE_RESET_TIME_US_MAX);
> +
> +       ret = reset_control_deassert(pcie_ep->core_reset);
> +       if (ret) {
> +               dev_err(dev, "Cannot de-assert core reset\n");
> +               return ret;
> +       }
> +
> +       usleep_range(CORE_RESET_TIME_US_MIN, CORE_RESET_TIME_US_MAX);
> +
> +       return 0;
> +}
> +
> +/*
> + * Delatch PERST_EN and PERST_SEPARATION_ENABLE with TCSR to avoid
> + * device reset during host reboot and hibernation. The driver is
> + * expected to handle this situation.
> + */
> +static void qcom_pcie_ep_configure_tcsr(struct qcom_pcie_ep *pcie_ep)
> +{
> +       regmap_write(pcie_ep->perst_map, pcie_ep->perst_en, 0);
> +       regmap_write(pcie_ep->perst_map, pcie_ep->perst_sep_en, 0);
> +}
> +
> +static int qcom_pcie_ep_enable_resources(struct qcom_pcie_ep *pcie_ep)
> +{
> +       return clk_bulk_prepare_enable(ARRAY_SIZE(qcom_pcie_ep_clks),
> +                                      qcom_pcie_ep_clks);
> +}
> +
> +static void qcom_pcie_ep_disable_resources(struct qcom_pcie_ep *pcie_ep)
> +{
> +       clk_bulk_disable_unprepare(ARRAY_SIZE(qcom_pcie_ep_clks),
> +                                  qcom_pcie_ep_clks);
> +}
> +
> +static int qcom_pcie_ep_core_init(struct qcom_pcie_ep *pcie_ep)
> +{
> +       struct dw_pcie *pci = &pcie_ep->pci;
> +       u32 val;
> +
> +       /* Disable BDF to SID mapping */
> +       val = readl(pcie_ep->parf + PARF_BDF_TO_SID_CFG);
> +       val |= BIT(0);
> +       writel(val, pcie_ep->parf + PARF_BDF_TO_SID_CFG);
> +
> +       /* Enable debug IRQ */
> +       writel((BIT(3) | BIT(2) | BIT(1)), pcie_ep->parf + PARF_DEBUG_INT_EN);
> +
> +       /* Configure PCIe to endpoint mode */
> +       writel(0x0, pcie_ep->parf + PARF_DEVICE_TYPE);
> +
> +       /* Allow entering L1 state */
> +       val = readl(pcie_ep->parf + PARF_PM_CTRL);
> +       val &= ~BIT(5);
> +       writel(val, pcie_ep->parf + PARF_PM_CTRL);
> +
> +       /* Read halts write */
> +       writel(0x0, pcie_ep->parf + PARF_AXI_MSTR_RD_HALT_NO_WRITES);
> +       /* Write after write halt */
> +       writel(BIT(31), pcie_ep->parf + PARF_AXI_MSTR_WR_ADDR_HALT);
> +       /* Q2A flush disable */
> +       writel(0, pcie_ep->parf + PARF_Q2A_FLUSH);
> +
> +       /* Disable the DBI Wakeup */
> +       writel(BIT(11), pcie_ep->parf + PARF_SYS_CTRL);
> +       /* Disable the debouncers */
> +       writel(0x73, pcie_ep->parf + PARF_DB_CTRL);
> +       /* Disable core clock CGC */
> +       writel(BIT(6), pcie_ep->parf + PARF_SYS_CTRL);
> +       /* Set AUX power to be on */
> +       writel(BIT(4), pcie_ep->parf + PARF_SYS_CTRL);
> +       /* Request to exit from L1SS for MSI and LTR MSG */
> +       writel(BIT(1), pcie_ep->parf + PARF_CFG_BITS);
> +
> +       dw_pcie_dbi_ro_wr_en(pci);
> +
> +       /* Set the PMC Register - to support PME in D0/D3hot/D3cold */
> +       val = dw_pcie_readl_dbi(pci, DBI_CAP_ID_NXT_PTR);
> +       val |= BIT(31) | BIT(30) | BIT(27);
> +       dw_pcie_writel_dbi(pci, DBI_CAP_ID_NXT_PTR, val);
> +
> +       /* Set the Endpoint L0s Acceptable Latency to 1us (max) */
> +       val = dw_pcie_readl_dbi(pci, DBI_DEVICE_CAPABILITIES);
> +       val |= FIELD_PREP(DBI_L0S_ACCPT_LATENCY_MASK, 0x7);
> +       dw_pcie_writel_dbi(pci, DBI_DEVICE_CAPABILITIES, val);
> +
> +       /* Set the Endpoint L1 Acceptable Latency to 1us (max) */
> +       val = dw_pcie_readl_dbi(pci, DBI_DEVICE_CAPABILITIES);
> +       val |= FIELD_PREP(DBI_L1_ACCPT_LATENCY_MASK, 0x7);
> +       dw_pcie_writel_dbi(pci, DBI_DEVICE_CAPABILITIES, val);
> +
> +       /* Set the L0s Exit Latency to 2us-4us = 0x6 */
> +       val = dw_pcie_readl_dbi(pci, DBI_LINK_CAPABILITIES);
> +       val |= FIELD_PREP(DBI_L0S_EXIT_LATENCY_MASK, 0x6);
> +       dw_pcie_writel_dbi(pci, DBI_LINK_CAPABILITIES, val);
> +
> +       /* Set the L1 Exit Latency to be 32us-64 us = 0x6 */
> +       val = dw_pcie_readl_dbi(pci, DBI_LINK_CAPABILITIES);
> +       val |= FIELD_PREP(DBI_L1_EXIT_LATENCY_MASK, 0x6);
> +       dw_pcie_writel_dbi(pci, DBI_LINK_CAPABILITIES, val);
> +
> +       /* L1ss is supported */
> +       val = dw_pcie_readl_dbi(pci, DBI_L1SUB_CAPABILITY);
> +       val |= 0x1f;
> +       dw_pcie_writel_dbi(pci, DBI_L1SUB_CAPABILITY, val);
> +
> +       /* Enable Clock Power Management */
> +       val = dw_pcie_readl_dbi(pci, DBI_LINK_CAPABILITIES);
> +       val |= BIT(18);
> +       dw_pcie_writel_dbi(pci, DBI_LINK_CAPABILITIES, val);

Lots of magic values that need defines.

> +
> +       dw_pcie_dbi_ro_wr_dis(pci);
> +
> +       /* Set FTS value to match the PHY setting */
> +       val = dw_pcie_readl_dbi(pci, DBI_ACK_F_ASPM_CTRL);
> +       val |= FIELD_PREP(DBI_ACK_N_FTS_MASK, 0x80);
> +       dw_pcie_writel_dbi(pci, DBI_ACK_F_ASPM_CTRL, val);
> +
> +       writel(0, pcie_ep->parf + PARF_INT_ALL_MASK);
> +       val = BIT(QCOM_PCIE_EP_INT_LINK_DOWN) |
> +               BIT(QCOM_PCIE_EP_INT_BME) |
> +               BIT(QCOM_PCIE_EP_INT_PM_TURNOFF) |
> +               BIT(QCOM_PCIE_EP_INT_DSTATE_CHANGE) |
> +               BIT(QCOM_PCIE_EP_INT_LINK_UP);

Move BIT() into the defines.

> +       writel(val, pcie_ep->parf + PARF_INT_ALL_MASK);
> +
> +       return 0;
> +}
> +
> +static int qcom_pcie_confirm_linkup(struct dw_pcie *pci)
> +{
> +       struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
> +       u32 reg;
> +
> +       reg = readl(pcie_ep->elbi + ELBI_SYS_STTS);
> +
> +       return reg & XMLH_LINK_UP;
> +}
> +
> +static int qcom_pcie_start_link(struct dw_pcie *pci)
> +{
> +       struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
> +
> +       enable_irq(pcie_ep->perst_irq);
> +
> +       return 0;
> +}
> +
> +static void qcom_pcie_stop_link(struct dw_pcie *pci)
> +{
> +       struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
> +
> +       disable_irq(pcie_ep->perst_irq);
> +}
> +
> +static int qcom_pcie_establish_link(struct dw_pcie *pci)
> +{
> +       struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
> +       struct device *dev = pci->dev;
> +       int ret;
> +
> +       ret = qcom_pcie_ep_enable_resources(pcie_ep);
> +       if (ret)
> +               return ret;
> +
> +       ret = qcom_pcie_ep_core_reset(pcie_ep);
> +       if (ret)
> +               goto err_disable_resources;
> +
> +       ret = phy_init(pcie_ep->phy);
> +       if (ret)
> +               goto err_disable_resources;
> +
> +       ret = phy_power_on(pcie_ep->phy);
> +       if (ret)
> +               goto err_phy_exit;
> +
> +       /* Assert WAKE# to RC to indicate device is ready */
> +       gpiod_set_value_cansleep(pcie_ep->wake, 1);
> +       usleep_range(WAKE_DELAY_US, WAKE_DELAY_US + 500);
> +       gpiod_set_value_cansleep(pcie_ep->wake, 0);
> +
> +       qcom_pcie_ep_configure_tcsr(pcie_ep);
> +
> +       ret = qcom_pcie_ep_core_init(pcie_ep);
> +       if (ret) {
> +               dev_err(dev, "Failed to init controller: %d\n", ret);
> +               goto err_phy_power_off;
> +       }
> +
> +       ret = dw_pcie_ep_init_complete(&pcie_ep->pci.ep);
> +       if (ret) {
> +               dev_err(dev, "Failed to complete initialization: %d\n", ret);
> +               goto err_phy_power_off;
> +       }
> +
> +       /*
> +        * The physical address of the MMIO region which is exposed as the BAR
> +        * should be written to MHI BASE registers.
> +        */
> +       writel(pcie_ep->mmio_phys, pcie_ep->parf + PARF_MHI_BASE_ADDR_LOWER);
> +       writel(0, pcie_ep->parf + PARF_MHI_BASE_ADDR_UPPER);
> +
> +       dw_pcie_ep_init_notify(&pcie_ep->pci.ep);
> +
> +       qcom_pcie_ep_enable_ltssm(pcie_ep);
> +
> +       return 0;
> +
> +err_phy_power_off:
> +       phy_power_off(pcie_ep->phy);
> +err_phy_exit:
> +       phy_exit(pcie_ep->phy);
> +err_disable_resources:
> +       qcom_pcie_ep_disable_resources(pcie_ep);
> +
> +       return ret;
> +}
> +
> +static void qcom_pcie_disable_link(struct dw_pcie *pci)
> +{
> +       struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
> +       struct device *dev = pci->dev;
> +
> +       if (pcie_ep->link_status == QCOM_PCIE_EP_LINK_DISABLED) {
> +               dev_dbg(dev, "Link is already disabled\n");
> +               return;
> +       }
> +
> +       phy_power_off(pcie_ep->phy);
> +       phy_exit(pcie_ep->phy);
> +       qcom_pcie_ep_disable_resources(pcie_ep);
> +       pcie_ep->link_status = QCOM_PCIE_EP_LINK_DISABLED;
> +}
> +
> +/* Common DWC controller ops */
> +static const struct dw_pcie_ops pci_ops = {
> +       .link_up = qcom_pcie_confirm_linkup,
> +       .start_link = qcom_pcie_start_link,
> +       .stop_link = qcom_pcie_stop_link,
> +};
> +
> +static int qcom_pcie_ep_get_io_resources(struct platform_device *pdev,
> +                                        struct qcom_pcie_ep *pcie_ep)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct dw_pcie *pci = &pcie_ep->pci;
> +       struct device_node *syscon;
> +       struct resource *res;
> +       int ret;
> +
> +       pcie_ep->parf = devm_platform_ioremap_resource_byname(pdev, "parf");
> +       if (IS_ERR(pcie_ep->parf))
> +               return PTR_ERR(pcie_ep->parf);
> +
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> +       pci->dbi_base = devm_pci_remap_cfg_resource(dev, res);
> +       if (IS_ERR(pci->dbi_base))
> +               return PTR_ERR(pci->dbi_base);
> +       pci->dbi_base2 = pci->dbi_base;
> +       pcie_ep->dbi_phys = res->start;
> +
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
> +       pcie_ep->elbi = devm_pci_remap_cfg_resource(dev, res);
> +       if (IS_ERR(pcie_ep->elbi))
> +               return PTR_ERR(pcie_ep->elbi);
> +
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "atu");
> +       pci->atu_base = devm_pci_remap_cfg_resource(dev, res);

The DWC core does this for you.

> +       if (IS_ERR(pci->atu_base))
> +               return PTR_ERR(pci->atu_base);
> +       pcie_ep->atu_phys = res->start;
> +
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mmio");
> +       pcie_ep->mmio = devm_ioremap_resource(dev, res);
> +       if (IS_ERR(pcie_ep->mmio))
> +               return PTR_ERR(pcie_ep->mmio);
> +       pcie_ep->mmio_phys = res->start;
> +       pcie_ep->mmio_size = resource_size(res);
> +
> +       syscon = of_parse_phandle(dev->of_node, "qcom,perst-regs", 0);
> +       if (!syscon) {
> +               dev_err(dev, "Failed to parse qcom,perst-regs\n");
> +               return -EINVAL;
> +       }
> +
> +       pcie_ep->perst_map = syscon_node_to_regmap(syscon);
> +       of_node_put(syscon);
> +       if (IS_ERR(pcie_ep->perst_map))
> +               return PTR_ERR(pcie_ep->perst_map);
> +
> +       ret = of_property_read_u32_index(dev->of_node, "qcom,perst-regs",
> +                                        1, &pcie_ep->perst_en);
> +       if (ret < 0) {
> +               dev_err(dev, "No Perst Enable offset in syscon\n");
> +               return ret;
> +       }
> +
> +       ret = of_property_read_u32_index(dev->of_node, "qcom,perst-regs",
> +                                        2, &pcie_ep->perst_sep_en);
> +       if (ret < 0) {
> +               dev_err(dev, "No Perst Separation Enable offset in syscon\n");
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int qcom_pcie_ep_get_resources(struct platform_device *pdev,
> +                                     struct qcom_pcie_ep *pcie_ep)
> +{
> +       struct device *dev = &pdev->dev;
> +       int ret;
> +
> +       ret = qcom_pcie_ep_get_io_resources(pdev, pcie_ep);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to get io resources %d\n", ret);
> +               return ret;
> +       }
> +
> +       ret = devm_clk_bulk_get(dev, ARRAY_SIZE(qcom_pcie_ep_clks),
> +                               qcom_pcie_ep_clks);
> +       if (ret)
> +               return ret;
> +
> +       pcie_ep->core_reset = devm_reset_control_get_exclusive(dev, "core");
> +       if (IS_ERR(pcie_ep->core_reset))
> +               return PTR_ERR(pcie_ep->core_reset);
> +
> +       pcie_ep->reset = devm_gpiod_get(dev, "reset", GPIOD_IN);
> +       if (IS_ERR(pcie_ep->reset))
> +               return PTR_ERR(pcie_ep->reset);
> +
> +       pcie_ep->wake = devm_gpiod_get_optional(dev, "wake", GPIOD_OUT_LOW);
> +       if (IS_ERR(pcie_ep->wake))
> +               return PTR_ERR(pcie_ep->wake);
> +
> +       pcie_ep->phy = devm_phy_optional_get(&pdev->dev, "pciephy");
> +       if (IS_ERR(pcie_ep->phy))
> +               ret = PTR_ERR(pcie_ep->phy);
> +
> +       return ret;
> +}
> +
> +/* TODO: Notify clients about PCIe state change */
> +static irqreturn_t qcom_pcie_ep_global_threaded_irq(int irq, void *data)
> +{
> +       struct qcom_pcie_ep *pcie_ep = data;
> +       struct dw_pcie *pci = &pcie_ep->pci;
> +       struct device *dev = pci->dev;
> +       unsigned long status = readl(pcie_ep->parf + PARF_INT_ALL_STATUS);
> +       u32 mask = readl(pcie_ep->parf + PARF_INT_ALL_MASK);
> +       u32 dstate, event, val;
> +
> +       writel(status, pcie_ep->parf + PARF_INT_ALL_CLEAR);
> +       status &= mask;
> +
> +       for_each_set_bit(event, &status, QCOM_PCIE_EP_INT_MAX) {
> +               switch (event) {
> +               case QCOM_PCIE_EP_INT_LINK_DOWN:
> +                       dev_dbg(dev, "Received Linkdown event\n");
> +                       pcie_ep->link_status = QCOM_PCIE_EP_LINK_DOWN;
> +                       break;
> +               case QCOM_PCIE_EP_INT_BME:
> +                       dev_dbg(dev, "Received BME event. Link is enabled!\n");
> +                       pcie_ep->link_status = QCOM_PCIE_EP_LINK_ENABLED;
> +                       break;
> +               case QCOM_PCIE_EP_INT_PM_TURNOFF:
> +                       dev_dbg(dev, "Received PM Turn-off event! Entering L23\n");
> +                       val = readl(pcie_ep->parf + PARF_PM_CTRL);
> +                       val |= BIT(2);
> +                       writel(val, pcie_ep->parf + PARF_PM_CTRL);
> +                       break;
> +               case QCOM_PCIE_EP_INT_DSTATE_CHANGE:
> +                       dstate = dw_pcie_readl_dbi(pci, DBI_CON_STATUS) & 0x3;
> +                       dev_dbg(dev, "Received D%d state event\n", dstate);
> +                       if (dstate == 3) {
> +                               val = readl(pcie_ep->parf + PARF_PM_CTRL);
> +                               val |= BIT(1);
> +                               writel(val, pcie_ep->parf + PARF_PM_CTRL);
> +                       }
> +                       break;
> +               case QCOM_PCIE_EP_INT_LINK_UP:
> +                       dev_dbg(dev, "Received Linkup event. Enumeration complete!\n");
> +                       dw_pcie_ep_linkup(&pci->ep);
> +                       pcie_ep->link_status = QCOM_PCIE_EP_LINK_UP;
> +                       break;
> +               default:
> +                       dev_dbg(dev, "Received unknown event: %d\n", event);
> +                       break;
> +               }
> +       }
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t qcom_pcie_ep_perst_threaded_irq(int irq, void *data)
> +{
> +       struct qcom_pcie_ep *pcie_ep = data;
> +       struct dw_pcie *pci = &pcie_ep->pci;
> +       struct device *dev = pci->dev;
> +       u32 perst;
> +
> +       perst = gpiod_get_value(pcie_ep->reset);
> +
> +       if (perst) {
> +               dev_dbg(dev, "PERST de-asserted by host. Starting link training!\n");
> +               qcom_pcie_establish_link(pci);
> +       } else {
> +               dev_dbg(dev, "PERST asserted by host. Shutting down the PCIe link!\n");
> +               qcom_pcie_disable_link(pci);
> +       }
> +
> +       irq_set_irq_type(gpiod_to_irq(pcie_ep->reset),
> +                        (perst ? IRQF_TRIGGER_LOW : IRQF_TRIGGER_HIGH));
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static int qcom_pcie_ep_enable_irq_resources(struct platform_device *pdev,
> +                                            struct qcom_pcie_ep *pcie_ep)
> +{
> +       int irq, ret;
> +
> +       irq = platform_get_irq_byname(pdev, "global");
> +       if (irq < 0) {
> +               dev_err(&pdev->dev, "Failed to get Global IRQ\n");
> +               return irq;
> +       }
> +
> +       ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
> +                                       qcom_pcie_ep_global_threaded_irq,
> +                                       IRQF_ONESHOT,
> +                                       "global_irq", pcie_ep);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to request Global IRQ\n");
> +               return ret;
> +       }
> +
> +       pcie_ep->perst_irq = gpiod_to_irq(pcie_ep->reset);
> +       irq_set_status_flags(pcie_ep->perst_irq, IRQ_NOAUTOEN);
> +       ret = devm_request_threaded_irq(&pdev->dev, pcie_ep->perst_irq, NULL,
> +                                       qcom_pcie_ep_perst_threaded_irq,
> +                                       IRQF_TRIGGER_HIGH | IRQF_ONESHOT,

IRQ_TRIGGER_* should come from the DT.

> +                                       "perst_irq", pcie_ep);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to request PERST IRQ\n");
> +               disable_irq(irq);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int qcom_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> +                                 enum pci_epc_irq_type type, u16 interrupt_num)
> +{
> +       struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +
> +       switch (type) {
> +       case PCI_EPC_IRQ_LEGACY:
> +               return dw_pcie_ep_raise_legacy_irq(ep, func_no);
> +       case PCI_EPC_IRQ_MSI:
> +               return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> +       default:
> +               dev_err(pci->dev, "Unknown IRQ type\n");
> +               return -EINVAL;
> +       }
> +}
> +
> +static const struct pci_epc_features qcom_pcie_epc_features = {
> +       .linkup_notifier = true,
> +       .core_init_notifier = true,
> +       .msi_capable = true,
> +       .msix_capable = false,
> +};
> +
> +static const struct pci_epc_features *
> +qcom_pcie_epc_get_features(struct dw_pcie_ep *pci_ep)
> +{
> +       return &qcom_pcie_epc_features;
> +}
> +
> +static void qcom_pcie_ep_init(struct dw_pcie_ep *ep)
> +{
> +       struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +       enum pci_barno bar;
> +
> +       for (bar = BAR_0; bar <= BAR_5; bar++)
> +               dw_pcie_ep_reset_bar(pci, bar);
> +}
> +
> +static struct dw_pcie_ep_ops pci_ep_ops = {
> +       .ep_init = qcom_pcie_ep_init,
> +       .raise_irq = qcom_pcie_ep_raise_irq,
> +       .get_features = qcom_pcie_epc_get_features,
> +};
> +
> +static int qcom_pcie_ep_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct qcom_pcie_ep *pcie_ep;
> +       int ret;
> +
> +       pcie_ep = devm_kzalloc(dev, sizeof(*pcie_ep), GFP_KERNEL);
> +       if (!pcie_ep)
> +               return -ENOMEM;
> +
> +       pcie_ep->pci.dev = dev;
> +       pcie_ep->pci.ops = &pci_ops;
> +       pcie_ep->pci.ep.ops = &pci_ep_ops;
> +       platform_set_drvdata(pdev, pcie_ep);
> +
> +       ret = qcom_pcie_ep_get_resources(pdev, pcie_ep);
> +       if (ret)
> +               return ret;
> +
> +       ret = qcom_pcie_ep_enable_resources(pcie_ep);
> +       if (ret)
> +               return ret;
> +
> +       ret = qcom_pcie_ep_core_reset(pcie_ep);
> +       if (ret)
> +               goto err_disable_resources;
> +
> +       ret = phy_init(pcie_ep->phy);
> +       if (ret)
> +               goto err_disable_resources;
> +
> +       /* PHY needs to be powered on for dw_pcie_ep_init() */
> +       ret = phy_power_on(pcie_ep->phy);
> +       if (ret)
> +               goto err_phy_exit;
> +
> +       ret = dw_pcie_ep_init(&pcie_ep->pci.ep);
> +       if (ret) {
> +               dev_err(dev, "Failed to initialize endpoint:%d\n", ret);
> +               goto err_phy_power_off;
> +       }
> +
> +       ret = qcom_pcie_ep_enable_irq_resources(pdev, pcie_ep);
> +       if (ret)
> +               goto err_phy_power_off;
> +
> +       return 0;
> +
> +err_phy_power_off:
> +       phy_power_off(pcie_ep->phy);
> +err_phy_exit:
> +       phy_exit(pcie_ep->phy);
> +err_disable_resources:
> +       qcom_pcie_ep_disable_resources(pcie_ep);
> +
> +       return ret;
> +}
> +
> +static int qcom_pcie_ep_remove(struct platform_device *pdev)
> +{
> +       struct qcom_pcie_ep *pcie_ep = platform_get_drvdata(pdev);
> +
> +       if (pcie_ep->link_status == QCOM_PCIE_EP_LINK_DISABLED)
> +               return 0;
> +
> +       phy_power_off(pcie_ep->phy);
> +       phy_exit(pcie_ep->phy);
> +       qcom_pcie_ep_disable_resources(pcie_ep);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id qcom_pcie_ep_match[] = {
> +       { .compatible = "qcom,sdx55-pcie-ep", },
> +       { }
> +};
> +
> +static struct platform_driver qcom_pcie_ep_driver = {
> +       .probe  = qcom_pcie_ep_probe,
> +       .remove = qcom_pcie_ep_remove,
> +       .driver = {
> +               .name = "qcom-pcie-ep",
> +               .of_match_table = qcom_pcie_ep_match,
> +       },
> +};
> +builtin_platform_driver(qcom_pcie_ep_driver);
> +
> +MODULE_AUTHOR("Siddartha Mohanadoss <smohanad@codeaurora.org>");
> +MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
> +MODULE_DESCRIPTION("Qualcomm PCIe Endpoint controller driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.25.1
>