treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / pci / controller / dwc / pcie-tegra194.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * PCIe host controller driver for Tegra194 SoC
 *
 * Copyright (C) 2019 NVIDIA Corporation.
 *
 * Author: Vidya Sagar <vidyas@nvidia.com>
 */

#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/phy/phy.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/random.h>
#include <linux/reset.h>
#include <linux/resource.h>
#include <linux/types.h>
#include "pcie-designware.h"
#include <soc/tegra/bpmp.h>
#include <soc/tegra/bpmp-abi.h>
#include "../../pci.h"

#define APPL_PINMUX                             0x0
#define APPL_PINMUX_PEX_RST                     BIT(0)
#define APPL_PINMUX_CLKREQ_OVERRIDE_EN          BIT(2)
#define APPL_PINMUX_CLKREQ_OVERRIDE             BIT(3)
#define APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN   BIT(4)
#define APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE      BIT(5)

#define APPL_CTRL                               0x4
#define APPL_CTRL_SYS_PRE_DET_STATE             BIT(6)
#define APPL_CTRL_LTSSM_EN                      BIT(7)
#define APPL_CTRL_HW_HOT_RST_EN                 BIT(20)
#define APPL_CTRL_HW_HOT_RST_MODE_MASK          GENMASK(1, 0)
#define APPL_CTRL_HW_HOT_RST_MODE_SHIFT         22
#define APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST      0x1

#define APPL_INTR_EN_L0_0                       0x8
#define APPL_INTR_EN_L0_0_LINK_STATE_INT_EN     BIT(0)
#define APPL_INTR_EN_L0_0_MSI_RCV_INT_EN        BIT(4)
#define APPL_INTR_EN_L0_0_INT_INT_EN            BIT(8)
#define APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN    BIT(19)
#define APPL_INTR_EN_L0_0_SYS_INTR_EN           BIT(30)
#define APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN       BIT(31)

#define APPL_INTR_STATUS_L0                     0xC
#define APPL_INTR_STATUS_L0_LINK_STATE_INT      BIT(0)
#define APPL_INTR_STATUS_L0_INT_INT             BIT(8)
#define APPL_INTR_STATUS_L0_CDM_REG_CHK_INT     BIT(18)

#define APPL_INTR_EN_L1_0_0                             0x1C
#define APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN     BIT(1)

#define APPL_INTR_STATUS_L1_0_0                         0x20
#define APPL_INTR_STATUS_L1_0_0_LINK_REQ_RST_NOT_CHGED  BIT(1)

#define APPL_INTR_STATUS_L1_1                   0x2C
#define APPL_INTR_STATUS_L1_2                   0x30
#define APPL_INTR_STATUS_L1_3                   0x34
#define APPL_INTR_STATUS_L1_6                   0x3C
#define APPL_INTR_STATUS_L1_7                   0x40

#define APPL_INTR_EN_L1_8_0                     0x44
#define APPL_INTR_EN_L1_8_BW_MGT_INT_EN         BIT(2)
#define APPL_INTR_EN_L1_8_AUTO_BW_INT_EN        BIT(3)
#define APPL_INTR_EN_L1_8_INTX_EN               BIT(11)
#define APPL_INTR_EN_L1_8_AER_INT_EN            BIT(15)

#define APPL_INTR_STATUS_L1_8_0                 0x4C
#define APPL_INTR_STATUS_L1_8_0_EDMA_INT_MASK   GENMASK(11, 6)
#define APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS  BIT(2)
#define APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS BIT(3)

#define APPL_INTR_STATUS_L1_9                   0x54
#define APPL_INTR_STATUS_L1_10                  0x58
#define APPL_INTR_STATUS_L1_11                  0x64
#define APPL_INTR_STATUS_L1_13                  0x74
#define APPL_INTR_STATUS_L1_14                  0x78
#define APPL_INTR_STATUS_L1_15                  0x7C
#define APPL_INTR_STATUS_L1_17                  0x88

#define APPL_INTR_EN_L1_18                              0x90
#define APPL_INTR_EN_L1_18_CDM_REG_CHK_CMPLT            BIT(2)
#define APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR          BIT(1)
#define APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR        BIT(0)

#define APPL_INTR_STATUS_L1_18                          0x94
#define APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMPLT        BIT(2)
#define APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMP_ERR      BIT(1)
#define APPL_INTR_STATUS_L1_18_CDM_REG_CHK_LOGIC_ERR    BIT(0)

#define APPL_MSI_CTRL_2                         0xB0

#define APPL_LTR_MSG_1                          0xC4
#define LTR_MSG_REQ                             BIT(15)
#define LTR_MST_NO_SNOOP_SHIFT                  16

#define APPL_LTR_MSG_2                          0xC8
#define APPL_LTR_MSG_2_LTR_MSG_REQ_STATE        BIT(3)

#define APPL_LINK_STATUS                        0xCC
#define APPL_LINK_STATUS_RDLH_LINK_UP           BIT(0)

#define APPL_DEBUG                              0xD0
#define APPL_DEBUG_PM_LINKST_IN_L2_LAT          BIT(21)
#define APPL_DEBUG_PM_LINKST_IN_L0              0x11
#define APPL_DEBUG_LTSSM_STATE_MASK             GENMASK(8, 3)
#define APPL_DEBUG_LTSSM_STATE_SHIFT            3
#define LTSSM_STATE_PRE_DETECT                  5

#define APPL_RADM_STATUS                        0xE4
#define APPL_PM_XMT_TURNOFF_STATE               BIT(0)

#define APPL_DM_TYPE                            0x100
#define APPL_DM_TYPE_MASK                       GENMASK(3, 0)
#define APPL_DM_TYPE_RP                         0x4
#define APPL_DM_TYPE_EP                         0x0

#define APPL_CFG_BASE_ADDR                      0x104
#define APPL_CFG_BASE_ADDR_MASK                 GENMASK(31, 12)

#define APPL_CFG_IATU_DMA_BASE_ADDR             0x108
#define APPL_CFG_IATU_DMA_BASE_ADDR_MASK        GENMASK(31, 18)

#define APPL_CFG_MISC                           0x110
#define APPL_CFG_MISC_SLV_EP_MODE               BIT(14)
#define APPL_CFG_MISC_ARCACHE_MASK              GENMASK(13, 10)
#define APPL_CFG_MISC_ARCACHE_SHIFT             10
#define APPL_CFG_MISC_ARCACHE_VAL               3

#define APPL_CFG_SLCG_OVERRIDE                  0x114
#define APPL_CFG_SLCG_OVERRIDE_SLCG_EN_MASTER   BIT(0)

#define APPL_CAR_RESET_OVRD                             0x12C
#define APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N     BIT(0)

#define IO_BASE_IO_DECODE                               BIT(0)
#define IO_BASE_IO_DECODE_BIT8                          BIT(8)

#define CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE              BIT(0)
#define CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE        BIT(16)

#define CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF 0x718
#define CFG_TIMER_CTRL_ACK_NAK_SHIFT    (19)

#define EVENT_COUNTER_ALL_CLEAR         0x3
#define EVENT_COUNTER_ENABLE_ALL        0x7
#define EVENT_COUNTER_ENABLE_SHIFT      2
#define EVENT_COUNTER_EVENT_SEL_MASK    GENMASK(7, 0)
#define EVENT_COUNTER_EVENT_SEL_SHIFT   16
#define EVENT_COUNTER_EVENT_Tx_L0S      0x2
#define EVENT_COUNTER_EVENT_Rx_L0S      0x3
#define EVENT_COUNTER_EVENT_L1          0x5
#define EVENT_COUNTER_EVENT_L1_1        0x7
#define EVENT_COUNTER_EVENT_L1_2        0x8
#define EVENT_COUNTER_GROUP_SEL_SHIFT   24
#define EVENT_COUNTER_GROUP_5           0x5

#define PORT_LOGIC_ACK_F_ASPM_CTRL                      0x70C
#define ENTER_ASPM                                      BIT(30)
#define L0S_ENTRANCE_LAT_SHIFT                          24
#define L0S_ENTRANCE_LAT_MASK                           GENMASK(26, 24)
#define L1_ENTRANCE_LAT_SHIFT                           27
#define L1_ENTRANCE_LAT_MASK                            GENMASK(29, 27)
#define N_FTS_SHIFT                                     8
#define N_FTS_MASK                                      GENMASK(7, 0)
#define N_FTS_VAL                                       52

#define PORT_LOGIC_GEN2_CTRL                            0x80C
#define PORT_LOGIC_GEN2_CTRL_DIRECT_SPEED_CHANGE        BIT(17)
#define FTS_MASK                                        GENMASK(7, 0)
#define FTS_VAL                                         52

#define PORT_LOGIC_MSI_CTRL_INT_0_EN            0x828

#define GEN3_EQ_CONTROL_OFF                     0x8a8
#define GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT  8
#define GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK   GENMASK(23, 8)
#define GEN3_EQ_CONTROL_OFF_FB_MODE_MASK        GENMASK(3, 0)

#define GEN3_RELATED_OFF                        0x890
#define GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL    BIT(0)
#define GEN3_RELATED_OFF_GEN3_EQ_DISABLE        BIT(16)
#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT  24
#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK   GENMASK(25, 24)

#define PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT  0x8D0
#define AMBA_ERROR_RESPONSE_CRS_SHIFT           3
#define AMBA_ERROR_RESPONSE_CRS_MASK            GENMASK(1, 0)
#define AMBA_ERROR_RESPONSE_CRS_OKAY            0
#define AMBA_ERROR_RESPONSE_CRS_OKAY_FFFFFFFF   1
#define AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001   2

#define PORT_LOGIC_MSIX_DOORBELL                        0x948

#define CAP_SPCIE_CAP_OFF                       0x154
#define CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK   GENMASK(3, 0)
#define CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK   GENMASK(11, 8)
#define CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT  8

#define PME_ACK_TIMEOUT 10000

#define LTSSM_TIMEOUT 50000     /* 50ms */

#define GEN3_GEN4_EQ_PRESET_INIT        5

#define GEN1_CORE_CLK_FREQ      62500000
#define GEN2_CORE_CLK_FREQ      125000000
#define GEN3_CORE_CLK_FREQ      250000000
#define GEN4_CORE_CLK_FREQ      500000000

static const unsigned int pcie_gen_freq[] = {
        GEN1_CORE_CLK_FREQ,
        GEN2_CORE_CLK_FREQ,
        GEN3_CORE_CLK_FREQ,
        GEN4_CORE_CLK_FREQ
};

static const u32 event_cntr_ctrl_offset[] = {
        0x1d8,
        0x1a8,
        0x1a8,
        0x1a8,
        0x1c4,
        0x1d8
};

static const u32 event_cntr_data_offset[] = {
        0x1dc,
        0x1ac,
        0x1ac,
        0x1ac,
        0x1c8,
        0x1dc
};

struct tegra_pcie_dw {
        struct device *dev;
        struct resource *appl_res;
        struct resource *dbi_res;
        struct resource *atu_dma_res;
        void __iomem *appl_base;
        struct clk *core_clk;
        struct reset_control *core_apb_rst;
        struct reset_control *core_rst;
        struct dw_pcie pci;
        struct tegra_bpmp *bpmp;

        bool supports_clkreq;
        bool enable_cdm_check;
        bool link_state;
        bool update_fc_fixup;
        u8 init_link_width;
        u32 msi_ctrl_int;
        u32 num_lanes;
        u32 max_speed;
        u32 cid;
        u32 cfg_link_cap_l1sub;
        u32 pcie_cap_base;
        u32 aspm_cmrt;
        u32 aspm_pwr_on_t;
        u32 aspm_l0s_enter_lat;

        struct regulator *pex_ctl_supply;
        struct regulator *slot_ctl_3v3;
        struct regulator *slot_ctl_12v;

        unsigned int phy_count;
        struct phy **phys;

        struct dentry *debugfs;
};

static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
{
        return container_of(pci, struct tegra_pcie_dw, pci);
}

static inline void appl_writel(struct tegra_pcie_dw *pcie, const u32 value,
                               const u32 reg)
{
        writel_relaxed(value, pcie->appl_base + reg);
}

static inline u32 appl_readl(struct tegra_pcie_dw *pcie, const u32 reg)
{
        return readl_relaxed(pcie->appl_base + reg);
}

struct tegra_pcie_soc {
        enum dw_pcie_device_mode mode;
};

static void apply_bad_link_workaround(struct pcie_port *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
        u32 current_link_width;
        u16 val;

        /*
         * NOTE:- Since this scenario is uncommon and link as such is not
         * stable anyway, not waiting to confirm if link is really
         * transitioning to Gen-2 speed
         */
        val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
        if (val & PCI_EXP_LNKSTA_LBMS) {
                current_link_width = (val & PCI_EXP_LNKSTA_NLW) >>
                                     PCI_EXP_LNKSTA_NLW_SHIFT;
                if (pcie->init_link_width > current_link_width) {
                        dev_warn(pci->dev, "PCIe link is bad, width reduced\n");
                        val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
                                                PCI_EXP_LNKCTL2);
                        val &= ~PCI_EXP_LNKCTL2_TLS;
                        val |= PCI_EXP_LNKCTL2_TLS_2_5GT;
                        dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
                                           PCI_EXP_LNKCTL2, val);

                        val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
                                                PCI_EXP_LNKCTL);
                        val |= PCI_EXP_LNKCTL_RL;
                        dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
                                           PCI_EXP_LNKCTL, val);
                }
        }
}

static irqreturn_t tegra_pcie_rp_irq_handler(struct tegra_pcie_dw *pcie)
{
        struct dw_pcie *pci = &pcie->pci;
        struct pcie_port *pp = &pci->pp;
        u32 val, tmp;
        u16 val_w;

        val = appl_readl(pcie, APPL_INTR_STATUS_L0);
        if (val & APPL_INTR_STATUS_L0_LINK_STATE_INT) {
                val = appl_readl(pcie, APPL_INTR_STATUS_L1_0_0);
                if (val & APPL_INTR_STATUS_L1_0_0_LINK_REQ_RST_NOT_CHGED) {
                        appl_writel(pcie, val, APPL_INTR_STATUS_L1_0_0);

                        /* SBR & Surprise Link Down WAR */
                        val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
                        val &= ~APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
                        appl_writel(pcie, val, APPL_CAR_RESET_OVRD);
                        udelay(1);
                        val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
                        val |= APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
                        appl_writel(pcie, val, APPL_CAR_RESET_OVRD);

                        val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
                        val |= PORT_LOGIC_GEN2_CTRL_DIRECT_SPEED_CHANGE;
                        dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
                }
        }

        if (val & APPL_INTR_STATUS_L0_INT_INT) {
                val = appl_readl(pcie, APPL_INTR_STATUS_L1_8_0);
                if (val & APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS) {
                        appl_writel(pcie,
                                    APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS,
                                    APPL_INTR_STATUS_L1_8_0);
                        apply_bad_link_workaround(pp);
                }
                if (val & APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS) {
                        appl_writel(pcie,
                                    APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS,
                                    APPL_INTR_STATUS_L1_8_0);

                        val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
                                                  PCI_EXP_LNKSTA);
                        dev_dbg(pci->dev, "Link Speed : Gen-%u\n", val_w &
                                PCI_EXP_LNKSTA_CLS);
                }
        }

        val = appl_readl(pcie, APPL_INTR_STATUS_L0);
        if (val & APPL_INTR_STATUS_L0_CDM_REG_CHK_INT) {
                val = appl_readl(pcie, APPL_INTR_STATUS_L1_18);
                tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS);
                if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMPLT) {
                        dev_info(pci->dev, "CDM check complete\n");
                        tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPLETE;
                }
                if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMP_ERR) {
                        dev_err(pci->dev, "CDM comparison mismatch\n");
                        tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPARISON_ERROR;
                }
                if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_LOGIC_ERR) {
                        dev_err(pci->dev, "CDM Logic error\n");
                        tmp |= PCIE_PL_CHK_REG_CHK_REG_LOGIC_ERROR;
                }
                dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, tmp);
                tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_ERR_ADDR);
                dev_err(pci->dev, "CDM Error Address Offset = 0x%08X\n", tmp);
        }

        return IRQ_HANDLED;
}

static irqreturn_t tegra_pcie_irq_handler(int irq, void *arg)
{
        struct tegra_pcie_dw *pcie = arg;

        return tegra_pcie_rp_irq_handler(pcie);
}

static int tegra_pcie_dw_rd_own_conf(struct pcie_port *pp, int where, int size,
                                     u32 *val)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);

        /*
         * This is an endpoint mode specific register happen to appear even
         * when controller is operating in root port mode and system hangs
         * when it is accessed with link being in ASPM-L1 state.
         * So skip accessing it altogether
         */
        if (where == PORT_LOGIC_MSIX_DOORBELL) {
                *val = 0x00000000;
                return PCIBIOS_SUCCESSFUL;
        }

        return dw_pcie_read(pci->dbi_base + where, size, val);
}

static int tegra_pcie_dw_wr_own_conf(struct pcie_port *pp, int where, int size,
                                     u32 val)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);

        /*
         * This is an endpoint mode specific register happen to appear even
         * when controller is operating in root port mode and system hangs
         * when it is accessed with link being in ASPM-L1 state.
         * So skip accessing it altogether
         */
        if (where == PORT_LOGIC_MSIX_DOORBELL)
                return PCIBIOS_SUCCESSFUL;

        return dw_pcie_write(pci->dbi_base + where, size, val);
}

#if defined(CONFIG_PCIEASPM)
static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
{
        u32 val;

        val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
        val &= ~PCI_L1SS_CAP_ASPM_L1_1;
        dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
}

static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
{
        u32 val;

        val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
        val &= ~PCI_L1SS_CAP_ASPM_L1_2;
        dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
}

static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
{
        u32 val;

        val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid]);
        val &= ~(EVENT_COUNTER_EVENT_SEL_MASK << EVENT_COUNTER_EVENT_SEL_SHIFT);
        val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
        val |= event << EVENT_COUNTER_EVENT_SEL_SHIFT;
        val |= EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
        dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
        val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_data_offset[pcie->cid]);

        return val;
}

static int aspm_state_cnt(struct seq_file *s, void *data)
{
        struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)
                                     dev_get_drvdata(s->private);
        u32 val;

        seq_printf(s, "Tx L0s entry count : %u\n",
                   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Tx_L0S));

        seq_printf(s, "Rx L0s entry count : %u\n",
                   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Rx_L0S));

        seq_printf(s, "Link L1 entry count : %u\n",
                   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1));

        seq_printf(s, "Link L1.1 entry count : %u\n",
                   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_1));

        seq_printf(s, "Link L1.2 entry count : %u\n",
                   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_2));

        /* Clear all counters */
        dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid],
                           EVENT_COUNTER_ALL_CLEAR);

        /* Re-enable counting */
        val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
        val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
        dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);

        return 0;
}

static void init_host_aspm(struct tegra_pcie_dw *pcie)
{
        struct dw_pcie *pci = &pcie->pci;
        u32 val;

        val = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
        pcie->cfg_link_cap_l1sub = val + PCI_L1SS_CAP;

        /* Enable ASPM counters */
        val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
        val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
        dw_pcie_writel_dbi(pci, event_cntr_ctrl_offset[pcie->cid], val);

        /* Program T_cmrt and T_pwr_on values */
        val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
        val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
        val |= (pcie->aspm_cmrt << 8);
        val |= (pcie->aspm_pwr_on_t << 19);
        dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);

        /* Program L0s and L1 entrance latencies */
        val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
        val &= ~L0S_ENTRANCE_LAT_MASK;
        val |= (pcie->aspm_l0s_enter_lat << L0S_ENTRANCE_LAT_SHIFT);
        val |= ENTER_ASPM;
        dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
}

static int init_debugfs(struct tegra_pcie_dw *pcie)
{
        struct dentry *d;

        d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
                                        pcie->debugfs, aspm_state_cnt);
        if (IS_ERR_OR_NULL(d))
                dev_err(pcie->dev,
                        "Failed to create debugfs file \"aspm_state_cnt\"\n");

        return 0;
}
#else
static inline void disable_aspm_l12(struct tegra_pcie_dw *pcie) { return; }
static inline void disable_aspm_l11(struct tegra_pcie_dw *pcie) { return; }
static inline void init_host_aspm(struct tegra_pcie_dw *pcie) { return; }
static inline int init_debugfs(struct tegra_pcie_dw *pcie) { return 0; }
#endif

static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
        u32 val;
        u16 val_w;

        val = appl_readl(pcie, APPL_INTR_EN_L0_0);
        val |= APPL_INTR_EN_L0_0_LINK_STATE_INT_EN;
        appl_writel(pcie, val, APPL_INTR_EN_L0_0);

        val = appl_readl(pcie, APPL_INTR_EN_L1_0_0);
        val |= APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN;
        appl_writel(pcie, val, APPL_INTR_EN_L1_0_0);

        if (pcie->enable_cdm_check) {
                val = appl_readl(pcie, APPL_INTR_EN_L0_0);
                val |= APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN;
                appl_writel(pcie, val, APPL_INTR_EN_L0_0);

                val = appl_readl(pcie, APPL_INTR_EN_L1_18);
                val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR;
                val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR;
                appl_writel(pcie, val, APPL_INTR_EN_L1_18);
        }

        val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
                                  PCI_EXP_LNKSTA);
        pcie->init_link_width = (val_w & PCI_EXP_LNKSTA_NLW) >>
                                PCI_EXP_LNKSTA_NLW_SHIFT;

        val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
                                  PCI_EXP_LNKCTL);
        val_w |= PCI_EXP_LNKCTL_LBMIE;
        dw_pcie_writew_dbi(&pcie->pci, pcie->pcie_cap_base + PCI_EXP_LNKCTL,
                           val_w);
}

static void tegra_pcie_enable_legacy_interrupts(struct pcie_port *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
        u32 val;

        /* Enable legacy interrupt generation */
        val = appl_readl(pcie, APPL_INTR_EN_L0_0);
        val |= APPL_INTR_EN_L0_0_SYS_INTR_EN;
        val |= APPL_INTR_EN_L0_0_INT_INT_EN;
        appl_writel(pcie, val, APPL_INTR_EN_L0_0);

        val = appl_readl(pcie, APPL_INTR_EN_L1_8_0);
        val |= APPL_INTR_EN_L1_8_INTX_EN;
        val |= APPL_INTR_EN_L1_8_AUTO_BW_INT_EN;
        val |= APPL_INTR_EN_L1_8_BW_MGT_INT_EN;
        if (IS_ENABLED(CONFIG_PCIEAER))
                val |= APPL_INTR_EN_L1_8_AER_INT_EN;
        appl_writel(pcie, val, APPL_INTR_EN_L1_8_0);
}

static void tegra_pcie_enable_msi_interrupts(struct pcie_port *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
        u32 val;

        dw_pcie_msi_init(pp);

        /* Enable MSI interrupt generation */
        val = appl_readl(pcie, APPL_INTR_EN_L0_0);
        val |= APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN;
        val |= APPL_INTR_EN_L0_0_MSI_RCV_INT_EN;
        appl_writel(pcie, val, APPL_INTR_EN_L0_0);
}

static void tegra_pcie_enable_interrupts(struct pcie_port *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);

        /* Clear interrupt statuses before enabling interrupts */
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L0);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_0_0);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_1);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_2);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_3);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_6);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_7);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_8_0);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_9);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_10);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_11);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_13);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_14);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_15);
        appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_17);

        tegra_pcie_enable_system_interrupts(pp);
        tegra_pcie_enable_legacy_interrupts(pp);
        if (IS_ENABLED(CONFIG_PCI_MSI))
                tegra_pcie_enable_msi_interrupts(pp);
}

static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
{
        struct dw_pcie *pci = &pcie->pci;
        u32 val, offset, i;

        /* Program init preset */
        for (i = 0; i < pcie->num_lanes; i++) {
                dw_pcie_read(pci->dbi_base + CAP_SPCIE_CAP_OFF
                                 + (i * 2), 2, &val);
                val &= ~CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK;
                val |= GEN3_GEN4_EQ_PRESET_INIT;
                val &= ~CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK;
                val |= (GEN3_GEN4_EQ_PRESET_INIT <<
                           CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT);
                dw_pcie_write(pci->dbi_base + CAP_SPCIE_CAP_OFF
                                 + (i * 2), 2, val);

                offset = dw_pcie_find_ext_capability(pci,
                                                     PCI_EXT_CAP_ID_PL_16GT) +
                                PCI_PL_16GT_LE_CTRL;
                dw_pcie_read(pci->dbi_base + offset + i, 1, &val);
                val &= ~PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK;
                val |= GEN3_GEN4_EQ_PRESET_INIT;
                val &= ~PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK;
                val |= (GEN3_GEN4_EQ_PRESET_INIT <<
                        PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT);
                dw_pcie_write(pci->dbi_base + offset + i, 1, val);
        }

        val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
        val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
        dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);

        val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
        val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
        val |= (0x3ff << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
        val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
        dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);

        val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
        val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
        val |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
        dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);

        val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
        val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
        val |= (0x360 << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
        val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
        dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);

        val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
        val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
        dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
}

static void tegra_pcie_prepare_host(struct pcie_port *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
        u32 val;

        val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
        val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
        dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);

        val = dw_pcie_readl_dbi(pci, PCI_PREF_MEMORY_BASE);
        val |= CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE;
        val |= CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE;
        dw_pcie_writel_dbi(pci, PCI_PREF_MEMORY_BASE, val);

        dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);

        /* Configure FTS */
        val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
        val &= ~(N_FTS_MASK << N_FTS_SHIFT);
        val |= N_FTS_VAL << N_FTS_SHIFT;
        dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);

        val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
        val &= ~FTS_MASK;
        val |= FTS_VAL;
        dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);

        /* Enable as 0xFFFF0001 response for CRS */
        val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
        val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
        val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
                AMBA_ERROR_RESPONSE_CRS_SHIFT);
        dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);

        /* Configure Max Speed from DT */
        if (pcie->max_speed && pcie->max_speed != -EINVAL) {
                val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base +
                                        PCI_EXP_LNKCAP);
                val &= ~PCI_EXP_LNKCAP_SLS;
                val |= pcie->max_speed;
                dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP,
                                   val);
        }

        /* Configure Max lane width from DT */
        val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP);
        val &= ~PCI_EXP_LNKCAP_MLW;
        val |= (pcie->num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT);
        dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP, val);

        config_gen3_gen4_eq_presets(pcie);

        init_host_aspm(pcie);

        val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
        val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
        dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);

        if (pcie->update_fc_fixup) {
                val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
                val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
                dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
        }

        dw_pcie_setup_rc(pp);

        clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);

        /* Assert RST */
        val = appl_readl(pcie, APPL_PINMUX);
        val &= ~APPL_PINMUX_PEX_RST;
        appl_writel(pcie, val, APPL_PINMUX);

        usleep_range(100, 200);

        /* Enable LTSSM */
        val = appl_readl(pcie, APPL_CTRL);
        val |= APPL_CTRL_LTSSM_EN;
        appl_writel(pcie, val, APPL_CTRL);

        /* De-assert RST */
        val = appl_readl(pcie, APPL_PINMUX);
        val |= APPL_PINMUX_PEX_RST;
        appl_writel(pcie, val, APPL_PINMUX);

        msleep(100);
}

static int tegra_pcie_dw_host_init(struct pcie_port *pp)
{
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
        u32 val, tmp, offset, speed;

        tegra_pcie_prepare_host(pp);

        if (dw_pcie_wait_for_link(pci)) {
                /*
                 * There are some endpoints which can't get the link up if
                 * root port has Data Link Feature (DLF) enabled.
                 * Refer Spec rev 4.0 ver 1.0 sec 3.4.2 & 7.7.4 for more info
                 * on Scaled Flow Control and DLF.
                 * So, need to confirm that is indeed the case here and attempt
                 * link up once again with DLF disabled.
                 */
                val = appl_readl(pcie, APPL_DEBUG);
                val &= APPL_DEBUG_LTSSM_STATE_MASK;
                val >>= APPL_DEBUG_LTSSM_STATE_SHIFT;
                tmp = appl_readl(pcie, APPL_LINK_STATUS);
                tmp &= APPL_LINK_STATUS_RDLH_LINK_UP;
                if (!(val == 0x11 && !tmp)) {
                        /* Link is down for all good reasons */
                        return 0;
                }

                dev_info(pci->dev, "Link is down in DLL");
                dev_info(pci->dev, "Trying again with DLFE disabled\n");
                /* Disable LTSSM */
                val = appl_readl(pcie, APPL_CTRL);
                val &= ~APPL_CTRL_LTSSM_EN;
                appl_writel(pcie, val, APPL_CTRL);

                reset_control_assert(pcie->core_rst);
                reset_control_deassert(pcie->core_rst);

                offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_DLF);
                val = dw_pcie_readl_dbi(pci, offset + PCI_DLF_CAP);
                val &= ~PCI_DLF_EXCHANGE_ENABLE;
                dw_pcie_writel_dbi(pci, offset, val);

                tegra_pcie_prepare_host(pp);

                if (dw_pcie_wait_for_link(pci))
                        return 0;
        }

        speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
                PCI_EXP_LNKSTA_CLS;
        clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);

        tegra_pcie_enable_interrupts(pp);

        return 0;
}

static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
{
        struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
        u32 val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);

        return !!(val & PCI_EXP_LNKSTA_DLLLA);
}

static void tegra_pcie_set_msi_vec_num(struct pcie_port *pp)
{
        pp->num_vectors = MAX_MSI_IRQS;
}

static const struct dw_pcie_ops tegra_dw_pcie_ops = {
        .link_up = tegra_pcie_dw_link_up,
};

static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
        .rd_own_conf = tegra_pcie_dw_rd_own_conf,
        .wr_own_conf = tegra_pcie_dw_wr_own_conf,
        .host_init = tegra_pcie_dw_host_init,
        .set_num_vectors = tegra_pcie_set_msi_vec_num,
};

static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
{
        unsigned int phy_count = pcie->phy_count;

        while (phy_count--) {
                phy_power_off(pcie->phys[phy_count]);
                phy_exit(pcie->phys[phy_count]);
        }
}

static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
{
        unsigned int i;
        int ret;

        for (i = 0; i < pcie->phy_count; i++) {
                ret = phy_init(pcie->phys[i]);
                if (ret < 0)
                        goto phy_power_off;

                ret = phy_power_on(pcie->phys[i]);
                if (ret < 0)
                        goto phy_exit;
        }

        return 0;

phy_power_off:
        while (i--) {
                phy_power_off(pcie->phys[i]);
phy_exit:
                phy_exit(pcie->phys[i]);
        }

        return ret;
}

static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
{
        struct device_node *np = pcie->dev->of_node;
        int ret;

        ret = of_property_read_u32(np, "nvidia,aspm-cmrt-us", &pcie->aspm_cmrt);
        if (ret < 0) {
                dev_info(pcie->dev, "Failed to read ASPM T_cmrt: %d\n", ret);
                return ret;
        }

        ret = of_property_read_u32(np, "nvidia,aspm-pwr-on-t-us",
                                   &pcie->aspm_pwr_on_t);
        if (ret < 0)
                dev_info(pcie->dev, "Failed to read ASPM Power On time: %d\n",
                         ret);

        ret = of_property_read_u32(np, "nvidia,aspm-l0s-entrance-latency-us",
                                   &pcie->aspm_l0s_enter_lat);
        if (ret < 0)
                dev_info(pcie->dev,
                         "Failed to read ASPM L0s Entrance latency: %d\n", ret);

        ret = of_property_read_u32(np, "num-lanes", &pcie->num_lanes);
        if (ret < 0) {
                dev_err(pcie->dev, "Failed to read num-lanes: %d\n", ret);
                return ret;
        }

        pcie->max_speed = of_pci_get_max_link_speed(np);

        ret = of_property_read_u32_index(np, "nvidia,bpmp", 1, &pcie->cid);
        if (ret) {
                dev_err(pcie->dev, "Failed to read Controller-ID: %d\n", ret);
                return ret;
        }

        ret = of_property_count_strings(np, "phy-names");
        if (ret < 0) {
                dev_err(pcie->dev, "Failed to find PHY entries: %d\n",
                        ret);
                return ret;
        }
        pcie->phy_count = ret;

        if (of_property_read_bool(np, "nvidia,update-fc-fixup"))
                pcie->update_fc_fixup = true;

        pcie->supports_clkreq =
                of_property_read_bool(pcie->dev->of_node, "supports-clkreq");

        pcie->enable_cdm_check =
                of_property_read_bool(np, "snps,enable-cdm-check");

        return 0;
}

static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
                                          bool enable)
{
        struct mrq_uphy_response resp;
        struct tegra_bpmp_message msg;
        struct mrq_uphy_request req;

        /* Controller-5 doesn't need to have its state set by BPMP-FW */
        if (pcie->cid == 5)
                return 0;

        memset(&req, 0, sizeof(req));
        memset(&resp, 0, sizeof(resp));

        req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
        req.controller_state.pcie_controller = pcie->cid;
        req.controller_state.enable = enable;

        memset(&msg, 0, sizeof(msg));
        msg.mrq = MRQ_UPHY;
        msg.tx.data = &req;
        msg.tx.size = sizeof(req);
        msg.rx.data = &resp;
        msg.rx.size = sizeof(resp);

        return tegra_bpmp_transfer(pcie->bpmp, &msg);
}

static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
{
        struct pcie_port *pp = &pcie->pci.pp;
        struct pci_bus *child, *root_bus = NULL;
        struct pci_dev *pdev;

        /*
         * link doesn't go into L2 state with some of the endpoints with Tegra
         * if they are not in D0 state. So, need to make sure that immediate
         * downstream devices are in D0 state before sending PME_TurnOff to put
         * link into L2 state.
         * This is as per PCI Express Base r4.0 v1.0 September 27-2017,
         * 5.2 Link State Power Management (Page #428).
         */

        list_for_each_entry(child, &pp->root_bus->children, node) {
                /* Bring downstream devices to D0 if they are not already in */
                if (child->parent == pp->root_bus) {
                        root_bus = child;
                        break;
                }
        }

        if (!root_bus) {
                dev_err(pcie->dev, "Failed to find downstream devices\n");
                return;
        }

        list_for_each_entry(pdev, &root_bus->devices, bus_list) {
                if (PCI_SLOT(pdev->devfn) == 0) {
                        if (pci_set_power_state(pdev, PCI_D0))
                                dev_err(pcie->dev,
                                        "Failed to transition %s to D0 state\n",
                                        dev_name(&pdev->dev));
                }
        }
}

static int tegra_pcie_get_slot_regulators(struct tegra_pcie_dw *pcie)
{
        pcie->slot_ctl_3v3 = devm_regulator_get_optional(pcie->dev, "vpcie3v3");
        if (IS_ERR(pcie->slot_ctl_3v3)) {
                if (PTR_ERR(pcie->slot_ctl_3v3) != -ENODEV)
                        return PTR_ERR(pcie->slot_ctl_3v3);

                pcie->slot_ctl_3v3 = NULL;
        }

        pcie->slot_ctl_12v = devm_regulator_get_optional(pcie->dev, "vpcie12v");
        if (IS_ERR(pcie->slot_ctl_12v)) {
                if (PTR_ERR(pcie->slot_ctl_12v) != -ENODEV)
                        return PTR_ERR(pcie->slot_ctl_12v);

                pcie->slot_ctl_12v = NULL;
        }

        return 0;
}

static int tegra_pcie_enable_slot_regulators(struct tegra_pcie_dw *pcie)
{
        int ret;

        if (pcie->slot_ctl_3v3) {
                ret = regulator_enable(pcie->slot_ctl_3v3);
                if (ret < 0) {
                        dev_err(pcie->dev,
                                "Failed to enable 3.3V slot supply: %d\n", ret);
                        return ret;
                }
        }

        if (pcie->slot_ctl_12v) {
                ret = regulator_enable(pcie->slot_ctl_12v);
                if (ret < 0) {
                        dev_err(pcie->dev,
                                "Failed to enable 12V slot supply: %d\n", ret);
                        goto fail_12v_enable;
                }
        }

        /*
         * According to PCI Express Card Electromechanical Specification
         * Revision 1.1, Table-2.4, T_PVPERL (Power stable to PERST# inactive)
         * should be a minimum of 100ms.
         */
        if (pcie->slot_ctl_3v3 || pcie->slot_ctl_12v)
                msleep(100);

        return 0;

fail_12v_enable:
        if (pcie->slot_ctl_3v3)
                regulator_disable(pcie->slot_ctl_3v3);
        return ret;
}

static void tegra_pcie_disable_slot_regulators(struct tegra_pcie_dw *pcie)
{
        if (pcie->slot_ctl_12v)
                regulator_disable(pcie->slot_ctl_12v);
        if (pcie->slot_ctl_3v3)
                regulator_disable(pcie->slot_ctl_3v3);
}

static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie,
                                        bool en_hw_hot_rst)
{
        int ret;
        u32 val;

        ret = tegra_pcie_bpmp_set_ctrl_state(pcie, true);
        if (ret) {
                dev_err(pcie->dev,
                        "Failed to enable controller %u: %d\n", pcie->cid, ret);
                return ret;
        }

        ret = tegra_pcie_enable_slot_regulators(pcie);
        if (ret < 0)
                goto fail_slot_reg_en;

        ret = regulator_enable(pcie->pex_ctl_supply);
        if (ret < 0) {
                dev_err(pcie->dev, "Failed to enable regulator: %d\n", ret);
                goto fail_reg_en;
        }

        ret = clk_prepare_enable(pcie->core_clk);
        if (ret) {
                dev_err(pcie->dev, "Failed to enable core clock: %d\n", ret);
                goto fail_core_clk;
        }

        ret = reset_control_deassert(pcie->core_apb_rst);
        if (ret) {
                dev_err(pcie->dev, "Failed to deassert core APB reset: %d\n",
                        ret);
                goto fail_core_apb_rst;
        }

        if (en_hw_hot_rst) {
                /* Enable HW_HOT_RST mode */
                val = appl_readl(pcie, APPL_CTRL);
                val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
                         APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
                val |= APPL_CTRL_HW_HOT_RST_EN;
                appl_writel(pcie, val, APPL_CTRL);
        }

        ret = tegra_pcie_enable_phy(pcie);
        if (ret) {
                dev_err(pcie->dev, "Failed to enable PHY: %d\n", ret);
                goto fail_phy;
        }

        /* Update CFG base address */
        appl_writel(pcie, pcie->dbi_res->start & APPL_CFG_BASE_ADDR_MASK,
                    APPL_CFG_BASE_ADDR);

        /* Configure this core for RP mode operation */
        appl_writel(pcie, APPL_DM_TYPE_RP, APPL_DM_TYPE);

        appl_writel(pcie, 0x0, APPL_CFG_SLCG_OVERRIDE);

        val = appl_readl(pcie, APPL_CTRL);
        appl_writel(pcie, val | APPL_CTRL_SYS_PRE_DET_STATE, APPL_CTRL);

        val = appl_readl(pcie, APPL_CFG_MISC);
        val |= (APPL_CFG_MISC_ARCACHE_VAL << APPL_CFG_MISC_ARCACHE_SHIFT);
        appl_writel(pcie, val, APPL_CFG_MISC);

        if (!pcie->supports_clkreq) {
                val = appl_readl(pcie, APPL_PINMUX);
                val |= APPL_PINMUX_CLKREQ_OVERRIDE_EN;
                val &= ~APPL_PINMUX_CLKREQ_OVERRIDE;
                appl_writel(pcie, val, APPL_PINMUX);
        }

        /* Update iATU_DMA base address */
        appl_writel(pcie,
                    pcie->atu_dma_res->start & APPL_CFG_IATU_DMA_BASE_ADDR_MASK,
                    APPL_CFG_IATU_DMA_BASE_ADDR);

        reset_control_deassert(pcie->core_rst);

        pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
                                                      PCI_CAP_ID_EXP);

        /* Disable ASPM-L1SS advertisement as there is no CLKREQ routing */
        if (!pcie->supports_clkreq) {
                disable_aspm_l11(pcie);
                disable_aspm_l12(pcie);
        }

        return ret;

fail_phy:
        reset_control_assert(pcie->core_apb_rst);
fail_core_apb_rst:
        clk_disable_unprepare(pcie->core_clk);
fail_core_clk:
        regulator_disable(pcie->pex_ctl_supply);
fail_reg_en:
        tegra_pcie_disable_slot_regulators(pcie);
fail_slot_reg_en:
        tegra_pcie_bpmp_set_ctrl_state(pcie, false);

        return ret;
}

static int __deinit_controller(struct tegra_pcie_dw *pcie)
{
        int ret;

        ret = reset_control_assert(pcie->core_rst);
        if (ret) {
                dev_err(pcie->dev, "Failed to assert \"core\" reset: %d\n",
                        ret);
                return ret;
        }

        tegra_pcie_disable_phy(pcie);

        ret = reset_control_assert(pcie->core_apb_rst);
        if (ret) {
                dev_err(pcie->dev, "Failed to assert APB reset: %d\n", ret);
                return ret;
        }

        clk_disable_unprepare(pcie->core_clk);

        ret = regulator_disable(pcie->pex_ctl_supply);
        if (ret) {
                dev_err(pcie->dev, "Failed to disable regulator: %d\n", ret);
                return ret;
        }

        tegra_pcie_disable_slot_regulators(pcie);

        ret = tegra_pcie_bpmp_set_ctrl_state(pcie, false);
        if (ret) {
                dev_err(pcie->dev, "Failed to disable controller %d: %d\n",
                        pcie->cid, ret);
                return ret;
        }

        return ret;
}

static int tegra_pcie_init_controller(struct tegra_pcie_dw *pcie)
{
        struct dw_pcie *pci = &pcie->pci;
        struct pcie_port *pp = &pci->pp;
        int ret;

        ret = tegra_pcie_config_controller(pcie, false);
        if (ret < 0)
                return ret;

        pp->ops = &tegra_pcie_dw_host_ops;

        ret = dw_pcie_host_init(pp);
        if (ret < 0) {
                dev_err(pcie->dev, "Failed to add PCIe port: %d\n", ret);
                goto fail_host_init;
        }

        return 0;

fail_host_init:
        return __deinit_controller(pcie);
}

static int tegra_pcie_try_link_l2(struct tegra_pcie_dw *pcie)
{
        u32 val;

        if (!tegra_pcie_dw_link_up(&pcie->pci))
                return 0;

        val = appl_readl(pcie, APPL_RADM_STATUS);
        val |= APPL_PM_XMT_TURNOFF_STATE;
        appl_writel(pcie, val, APPL_RADM_STATUS);

        return readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG, val,
                                 val & APPL_DEBUG_PM_LINKST_IN_L2_LAT,
                                 1, PME_ACK_TIMEOUT);
}

static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
{
        u32 data;
        int err;

        if (!tegra_pcie_dw_link_up(&pcie->pci)) {
                dev_dbg(pcie->dev, "PCIe link is not up...!\n");
                return;
        }

        if (tegra_pcie_try_link_l2(pcie)) {
                dev_info(pcie->dev, "Link didn't transition to L2 state\n");
                /*
                 * TX lane clock freq will reset to Gen1 only if link is in L2
                 * or detect state.
                 * So apply pex_rst to end point to force RP to go into detect
                 * state
                 */
                data = appl_readl(pcie, APPL_PINMUX);
                data &= ~APPL_PINMUX_PEX_RST;
                appl_writel(pcie, data, APPL_PINMUX);

                err = readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG,
                                                data,
                                                ((data &
                                                APPL_DEBUG_LTSSM_STATE_MASK) >>
                                                APPL_DEBUG_LTSSM_STATE_SHIFT) ==
                                                LTSSM_STATE_PRE_DETECT,
                                                1, LTSSM_TIMEOUT);
                if (err) {
                        dev_info(pcie->dev, "Link didn't go to detect state\n");
                } else {
                        /* Disable LTSSM after link is in detect state */
                        data = appl_readl(pcie, APPL_CTRL);
                        data &= ~APPL_CTRL_LTSSM_EN;
                        appl_writel(pcie, data, APPL_CTRL);
                }
        }
        /*
         * DBI registers may not be accessible after this as PLL-E would be
         * down depending on how CLKREQ is pulled by end point
         */
        data = appl_readl(pcie, APPL_PINMUX);
        data |= (APPL_PINMUX_CLKREQ_OVERRIDE_EN | APPL_PINMUX_CLKREQ_OVERRIDE);
        /* Cut REFCLK to slot */
        data |= APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN;
        data &= ~APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE;
        appl_writel(pcie, data, APPL_PINMUX);
}

static int tegra_pcie_deinit_controller(struct tegra_pcie_dw *pcie)
{
        tegra_pcie_downstream_dev_to_D0(pcie);
        dw_pcie_host_deinit(&pcie->pci.pp);
        tegra_pcie_dw_pme_turnoff(pcie);

        return __deinit_controller(pcie);
}

static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
{
        struct pcie_port *pp = &pcie->pci.pp;
        struct device *dev = pcie->dev;
        char *name;
        int ret;

        if (IS_ENABLED(CONFIG_PCI_MSI)) {
                pp->msi_irq = of_irq_get_byname(dev->of_node, "msi");
                if (!pp->msi_irq) {
                        dev_err(dev, "Failed to get MSI interrupt\n");
                        return -ENODEV;
                }
        }

        pm_runtime_enable(dev);

        ret = pm_runtime_get_sync(dev);
        if (ret < 0) {
                dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
                        ret);
                goto fail_pm_get_sync;
        }

        ret = pinctrl_pm_select_default_state(dev);
        if (ret < 0) {
                dev_err(dev, "Failed to configure sideband pins: %d\n", ret);
                goto fail_pinctrl;
        }

        tegra_pcie_init_controller(pcie);

        pcie->link_state = tegra_pcie_dw_link_up(&pcie->pci);
        if (!pcie->link_state) {
                ret = -ENOMEDIUM;
                goto fail_host_init;
        }

        name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
        if (!name) {
                ret = -ENOMEM;
                goto fail_host_init;
        }

        pcie->debugfs = debugfs_create_dir(name, NULL);
        if (!pcie->debugfs)
                dev_err(dev, "Failed to create debugfs\n");
        else
                init_debugfs(pcie);

        return ret;

fail_host_init:
        tegra_pcie_deinit_controller(pcie);
fail_pinctrl:
        pm_runtime_put_sync(dev);
fail_pm_get_sync:
        pm_runtime_disable(dev);
        return ret;
}

static int tegra_pcie_dw_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct resource *atu_dma_res;
        struct tegra_pcie_dw *pcie;
        struct resource *dbi_res;
        struct pcie_port *pp;
        struct dw_pcie *pci;
        struct phy **phys;
        char *name;
        int ret;
        u32 i;

        pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
        if (!pcie)
                return -ENOMEM;

        pci = &pcie->pci;
        pci->dev = &pdev->dev;
        pci->ops = &tegra_dw_pcie_ops;
        pp = &pci->pp;
        pcie->dev = &pdev->dev;

        ret = tegra_pcie_dw_parse_dt(pcie);
        if (ret < 0) {
                dev_err(dev, "Failed to parse device tree: %d\n", ret);
                return ret;
        }

        ret = tegra_pcie_get_slot_regulators(pcie);
        if (ret < 0) {
                dev_err(dev, "Failed to get slot regulators: %d\n", ret);
                return ret;
        }

        pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
        if (IS_ERR(pcie->pex_ctl_supply)) {
                ret = PTR_ERR(pcie->pex_ctl_supply);
                if (ret != -EPROBE_DEFER)
                        dev_err(dev, "Failed to get regulator: %ld\n",
                                PTR_ERR(pcie->pex_ctl_supply));
                return ret;
        }

        pcie->core_clk = devm_clk_get(dev, "core");
        if (IS_ERR(pcie->core_clk)) {
                dev_err(dev, "Failed to get core clock: %ld\n",
                        PTR_ERR(pcie->core_clk));
                return PTR_ERR(pcie->core_clk);
        }

        pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
                                                      "appl");
        if (!pcie->appl_res) {
                dev_err(dev, "Failed to find \"appl\" region\n");
                return -ENODEV;
        }

        pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
        if (IS_ERR(pcie->appl_base))
                return PTR_ERR(pcie->appl_base);

        pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
        if (IS_ERR(pcie->core_apb_rst)) {
                dev_err(dev, "Failed to get APB reset: %ld\n",
                        PTR_ERR(pcie->core_apb_rst));
                return PTR_ERR(pcie->core_apb_rst);
        }

        phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
        if (!phys)
                return -ENOMEM;

        for (i = 0; i < pcie->phy_count; i++) {
                name = kasprintf(GFP_KERNEL, "p2u-%u", i);
                if (!name) {
                        dev_err(dev, "Failed to create P2U string\n");
                        return -ENOMEM;
                }
                phys[i] = devm_phy_get(dev, name);
                kfree(name);
                if (IS_ERR(phys[i])) {
                        ret = PTR_ERR(phys[i]);
                        if (ret != -EPROBE_DEFER)
                                dev_err(dev, "Failed to get PHY: %d\n", ret);
                        return ret;
                }
        }

        pcie->phys = phys;

        dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
        if (!dbi_res) {
                dev_err(dev, "Failed to find \"dbi\" region\n");
                return -ENODEV;
        }
        pcie->dbi_res = dbi_res;

        pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
        if (IS_ERR(pci->dbi_base))
                return PTR_ERR(pci->dbi_base);

        /* Tegra HW locates DBI2 at a fixed offset from DBI */
        pci->dbi_base2 = pci->dbi_base + 0x1000;

        atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
                                                   "atu_dma");
        if (!atu_dma_res) {
                dev_err(dev, "Failed to find \"atu_dma\" region\n");
                return -ENODEV;
        }
        pcie->atu_dma_res = atu_dma_res;

        pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
        if (IS_ERR(pci->atu_base))
                return PTR_ERR(pci->atu_base);

        pcie->core_rst = devm_reset_control_get(dev, "core");
        if (IS_ERR(pcie->core_rst)) {
                dev_err(dev, "Failed to get core reset: %ld\n",
                        PTR_ERR(pcie->core_rst));
                return PTR_ERR(pcie->core_rst);
        }

        pp->irq = platform_get_irq_byname(pdev, "intr");
        if (!pp->irq) {
                dev_err(dev, "Failed to get \"intr\" interrupt\n");
                return -ENODEV;
        }

        ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
                               IRQF_SHARED, "tegra-pcie-intr", pcie);
        if (ret) {
                dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
                return ret;
        }

        pcie->bpmp = tegra_bpmp_get(dev);
        if (IS_ERR(pcie->bpmp))
                return PTR_ERR(pcie->bpmp);

        platform_set_drvdata(pdev, pcie);

        ret = tegra_pcie_config_rp(pcie);
        if (ret && ret != -ENOMEDIUM)
                goto fail;
        else
                return 0;

fail:
        tegra_bpmp_put(pcie->bpmp);
        return ret;
}

static int tegra_pcie_dw_remove(struct platform_device *pdev)
{
        struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);

        if (!pcie->link_state)
                return 0;

        debugfs_remove_recursive(pcie->debugfs);
        tegra_pcie_deinit_controller(pcie);
        pm_runtime_put_sync(pcie->dev);
        pm_runtime_disable(pcie->dev);
        tegra_bpmp_put(pcie->bpmp);

        return 0;
}

static int tegra_pcie_dw_suspend_late(struct device *dev)
{
        struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
        u32 val;

        if (!pcie->link_state)
                return 0;

        /* Enable HW_HOT_RST mode */
        val = appl_readl(pcie, APPL_CTRL);
        val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
                 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
        val |= APPL_CTRL_HW_HOT_RST_EN;
        appl_writel(pcie, val, APPL_CTRL);

        return 0;
}

static int tegra_pcie_dw_suspend_noirq(struct device *dev)
{
        struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);

        if (!pcie->link_state)
                return 0;

        /* Save MSI interrupt vector */
        pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
                                               PORT_LOGIC_MSI_CTRL_INT_0_EN);
        tegra_pcie_downstream_dev_to_D0(pcie);
        tegra_pcie_dw_pme_turnoff(pcie);

        return __deinit_controller(pcie);
}

static int tegra_pcie_dw_resume_noirq(struct device *dev)
{
        struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
        int ret;

        if (!pcie->link_state)
                return 0;

        ret = tegra_pcie_config_controller(pcie, true);
        if (ret < 0)
                return ret;

        ret = tegra_pcie_dw_host_init(&pcie->pci.pp);
        if (ret < 0) {
                dev_err(dev, "Failed to init host: %d\n", ret);
                goto fail_host_init;
        }

        /* Restore MSI interrupt vector */
        dw_pcie_writel_dbi(&pcie->pci, PORT_LOGIC_MSI_CTRL_INT_0_EN,
                           pcie->msi_ctrl_int);

        return 0;

fail_host_init:
        return __deinit_controller(pcie);
}

static int tegra_pcie_dw_resume_early(struct device *dev)
{
        struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
        u32 val;

        if (!pcie->link_state)
                return 0;

        /* Disable HW_HOT_RST mode */
        val = appl_readl(pcie, APPL_CTRL);
        val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
                 APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
        val |= APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST <<
               APPL_CTRL_HW_HOT_RST_MODE_SHIFT;
        val &= ~APPL_CTRL_HW_HOT_RST_EN;
        appl_writel(pcie, val, APPL_CTRL);

        return 0;
}

static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
{
        struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);

        if (!pcie->link_state)
                return;

        debugfs_remove_recursive(pcie->debugfs);
        tegra_pcie_downstream_dev_to_D0(pcie);

        disable_irq(pcie->pci.pp.irq);
        if (IS_ENABLED(CONFIG_PCI_MSI))
                disable_irq(pcie->pci.pp.msi_irq);

        tegra_pcie_dw_pme_turnoff(pcie);
        __deinit_controller(pcie);
}

static const struct of_device_id tegra_pcie_dw_of_match[] = {
        {
                .compatible = "nvidia,tegra194-pcie",
        },
        {},
};

static const struct dev_pm_ops tegra_pcie_dw_pm_ops = {
        .suspend_late = tegra_pcie_dw_suspend_late,
        .suspend_noirq = tegra_pcie_dw_suspend_noirq,
        .resume_noirq = tegra_pcie_dw_resume_noirq,
        .resume_early = tegra_pcie_dw_resume_early,
};

static struct platform_driver tegra_pcie_dw_driver = {
        .probe = tegra_pcie_dw_probe,
        .remove = tegra_pcie_dw_remove,
        .shutdown = tegra_pcie_dw_shutdown,
        .driver = {
                .name   = "tegra194-pcie",
                .pm = &tegra_pcie_dw_pm_ops,
                .of_match_table = tegra_pcie_dw_of_match,
        },
};
module_platform_driver(tegra_pcie_dw_driver);

MODULE_DEVICE_TABLE(of, tegra_pcie_dw_of_match);

MODULE_AUTHOR("Vidya Sagar <vidyas@nvidia.com>");
MODULE_DESCRIPTION("NVIDIA PCIe host controller driver");
MODULE_LICENSE("GPL v2");