// SPDX-License-Identifier: GPL-2.0
/*
 * PCI support in ACPI
 *
 * Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com>
 * Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com>
 * Copyright (C) 2004 Intel Corp.
 */

#include <linux/delay.h>
#include <linux/init.h>
#include <linux/irqdomain.h>
#include <linux/pci.h>
#include <linux/msi.h>
#include <linux/pci_hotplug.h>
#include <linux/module.h>
#include <linux/pci-acpi.h>
#include <linux/pm_runtime.h>
#include <linux/pm_qos.h>
#include <linux/rwsem.h>
#include "pci.h"

/*
 * The GUID is defined in the PCI Firmware Specification available here:
 * https://www.pcisig.com/members/downloads/pcifw_r3_1_13Dec10.pdf
 */
const guid_t pci_acpi_dsm_guid =
        GUID_INIT(0xe5c937d0, 0x3553, 0x4d7a,
                  0x91, 0x17, 0xea, 0x4d, 0x19, 0xc3, 0x43, 0x4d);

#if defined(CONFIG_PCI_QUIRKS) && defined(CONFIG_ARM64)
static int acpi_get_rc_addr(struct acpi_device *adev, struct resource *res)
{
        struct device *dev = &adev->dev;
        struct resource_entry *entry;
        struct list_head list;
        unsigned long flags;
        int ret;

        INIT_LIST_HEAD(&list);
        flags = IORESOURCE_MEM;
        ret = acpi_dev_get_resources(adev, &list,
                                     acpi_dev_filter_resource_type_cb,
                                     (void *) flags);
        if (ret < 0) {
                dev_err(dev, "failed to parse _CRS method, error code %d\n",
                        ret);
                return ret;
        }

        if (ret == 0) {
                dev_err(dev, "no IO and memory resources present in _CRS\n");
                return -EINVAL;
        }

        entry = list_first_entry(&list, struct resource_entry, node);
        *res = *entry->res;
        acpi_dev_free_resource_list(&list);
        return 0;
}

static acpi_status acpi_match_rc(acpi_handle handle, u32 lvl, void *context,
                                 void **retval)
{
        u16 *segment = context;
        unsigned long long uid;
        acpi_status status;

        status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
        if (ACPI_FAILURE(status) || uid != *segment)
                return AE_CTRL_DEPTH;

        *(acpi_handle *)retval = handle;
        return AE_CTRL_TERMINATE;
}

int acpi_get_rc_resources(struct device *dev, const char *hid, u16 segment,
                          struct resource *res)
{
        struct acpi_device *adev;
        acpi_status status;
        acpi_handle handle;
        int ret;

        status = acpi_get_devices(hid, acpi_match_rc, &segment, &handle);
        if (ACPI_FAILURE(status)) {
                dev_err(dev, "can't find _HID %s device to locate resources\n",
                        hid);
                return -ENODEV;
        }

        ret = acpi_bus_get_device(handle, &adev);
        if (ret)
                return ret;

        ret = acpi_get_rc_addr(adev, res);
        if (ret) {
                dev_err(dev, "can't get resource from %s\n",
                        dev_name(&adev->dev));
                return ret;
        }

        return 0;
}
#endif

phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
{
        acpi_status status = AE_NOT_EXIST;
        unsigned long long mcfg_addr;

        if (handle)
                status = acpi_evaluate_integer(handle, METHOD_NAME__CBA,
                                               NULL, &mcfg_addr);
        if (ACPI_FAILURE(status))
                return 0;

        return (phys_addr_t)mcfg_addr;
}

/* _HPX PCI Setting Record (Type 0); same as _HPP */
struct hpx_type0 {
        u32 revision;           /* Not present in _HPP */
        u8  cache_line_size;    /* Not applicable to PCIe */
        u8  latency_timer;      /* Not applicable to PCIe */
        u8  enable_serr;
        u8  enable_perr;
};

static struct hpx_type0 pci_default_type0 = {
        .revision = 1,
        .cache_line_size = 8,
        .latency_timer = 0x40,
        .enable_serr = 0,
        .enable_perr = 0,
};

static void program_hpx_type0(struct pci_dev *dev, struct hpx_type0 *hpx)
{
        u16 pci_cmd, pci_bctl;

        if (!hpx)
                hpx = &pci_default_type0;

        if (hpx->revision > 1) {
                pci_warn(dev, "PCI settings rev %d not supported; using defaults\n",
                         hpx->revision);
                hpx = &pci_default_type0;
        }

        pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE, hpx->cache_line_size);
        pci_write_config_byte(dev, PCI_LATENCY_TIMER, hpx->latency_timer);
        pci_read_config_word(dev, PCI_COMMAND, &pci_cmd);
        if (hpx->enable_serr)
                pci_cmd |= PCI_COMMAND_SERR;
        if (hpx->enable_perr)
                pci_cmd |= PCI_COMMAND_PARITY;
        pci_write_config_word(dev, PCI_COMMAND, pci_cmd);

        /* Program bridge control value */
        if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) {
                pci_write_config_byte(dev, PCI_SEC_LATENCY_TIMER,
                                      hpx->latency_timer);
                pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &pci_bctl);
                if (hpx->enable_perr)
                        pci_bctl |= PCI_BRIDGE_CTL_PARITY;
                pci_write_config_word(dev, PCI_BRIDGE_CONTROL, pci_bctl);
        }
}

static acpi_status decode_type0_hpx_record(union acpi_object *record,
                                           struct hpx_type0 *hpx0)
{
        int i;
        union acpi_object *fields = record->package.elements;
        u32 revision = fields[1].integer.value;

        switch (revision) {
        case 1:
                if (record->package.count != 6)
                        return AE_ERROR;
                for (i = 2; i < 6; i++)
                        if (fields[i].type != ACPI_TYPE_INTEGER)
                                return AE_ERROR;
                hpx0->revision        = revision;
                hpx0->cache_line_size = fields[2].integer.value;
                hpx0->latency_timer   = fields[3].integer.value;
                hpx0->enable_serr     = fields[4].integer.value;
                hpx0->enable_perr     = fields[5].integer.value;
                break;
        default:
                pr_warn("%s: Type 0 Revision %d record not supported\n",
                       __func__, revision);
                return AE_ERROR;
        }
        return AE_OK;
}

/* _HPX PCI-X Setting Record (Type 1) */
struct hpx_type1 {
        u32 revision;
        u8  max_mem_read;
        u8  avg_max_split;
        u16 tot_max_split;
};

static void program_hpx_type1(struct pci_dev *dev, struct hpx_type1 *hpx)
{
        int pos;

        if (!hpx)
                return;

        pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
        if (!pos)
                return;

        pci_warn(dev, "PCI-X settings not supported\n");
}

static acpi_status decode_type1_hpx_record(union acpi_object *record,
                                           struct hpx_type1 *hpx1)
{
        int i;
        union acpi_object *fields = record->package.elements;
        u32 revision = fields[1].integer.value;

        switch (revision) {
        case 1:
                if (record->package.count != 5)
                        return AE_ERROR;
                for (i = 2; i < 5; i++)
                        if (fields[i].type != ACPI_TYPE_INTEGER)
                                return AE_ERROR;
                hpx1->revision      = revision;
                hpx1->max_mem_read  = fields[2].integer.value;
                hpx1->avg_max_split = fields[3].integer.value;
                hpx1->tot_max_split = fields[4].integer.value;
                break;
        default:
                pr_warn("%s: Type 1 Revision %d record not supported\n",
                       __func__, revision);
                return AE_ERROR;
        }
        return AE_OK;
}

static bool pcie_root_rcb_set(struct pci_dev *dev)
{
        struct pci_dev *rp = pcie_find_root_port(dev);
        u16 lnkctl;

        if (!rp)
                return false;

        pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl);
        if (lnkctl & PCI_EXP_LNKCTL_RCB)
                return true;

        return false;
}

/* _HPX PCI Express Setting Record (Type 2) */
struct hpx_type2 {
        u32 revision;
        u32 unc_err_mask_and;
        u32 unc_err_mask_or;
        u32 unc_err_sever_and;
        u32 unc_err_sever_or;
        u32 cor_err_mask_and;
        u32 cor_err_mask_or;
        u32 adv_err_cap_and;
        u32 adv_err_cap_or;
        u16 pci_exp_devctl_and;
        u16 pci_exp_devctl_or;
        u16 pci_exp_lnkctl_and;
        u16 pci_exp_lnkctl_or;
        u32 sec_unc_err_sever_and;
        u32 sec_unc_err_sever_or;
        u32 sec_unc_err_mask_and;
        u32 sec_unc_err_mask_or;
};

static void program_hpx_type2(struct pci_dev *dev, struct hpx_type2 *hpx)
{
        int pos;
        u32 reg32;

        if (!hpx)
                return;

        if (!pci_is_pcie(dev))
                return;

        if (hpx->revision > 1) {
                pci_warn(dev, "PCIe settings rev %d not supported\n",
                         hpx->revision);
                return;
        }

        /*
         * Don't allow _HPX to change MPS or MRRS settings.  We manage
         * those to make sure they're consistent with the rest of the
         * platform.
         */
        hpx->pci_exp_devctl_and |= PCI_EXP_DEVCTL_PAYLOAD |
                                    PCI_EXP_DEVCTL_READRQ;
        hpx->pci_exp_devctl_or &= ~(PCI_EXP_DEVCTL_PAYLOAD |
                                    PCI_EXP_DEVCTL_READRQ);

        /* Initialize Device Control Register */
        pcie_capability_clear_and_set_word(dev, PCI_EXP_DEVCTL,
                        ~hpx->pci_exp_devctl_and, hpx->pci_exp_devctl_or);

        /* Initialize Link Control Register */
        if (pcie_cap_has_lnkctl(dev)) {

                /*
                 * If the Root Port supports Read Completion Boundary of
                 * 128, set RCB to 128.  Otherwise, clear it.
                 */
                hpx->pci_exp_lnkctl_and |= PCI_EXP_LNKCTL_RCB;
                hpx->pci_exp_lnkctl_or &= ~PCI_EXP_LNKCTL_RCB;
                if (pcie_root_rcb_set(dev))
                        hpx->pci_exp_lnkctl_or |= PCI_EXP_LNKCTL_RCB;

                pcie_capability_clear_and_set_word(dev, PCI_EXP_LNKCTL,
                        ~hpx->pci_exp_lnkctl_and, hpx->pci_exp_lnkctl_or);
        }

        /* Find Advanced Error Reporting Enhanced Capability */
        pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
        if (!pos)
                return;

        /* Initialize Uncorrectable Error Mask Register */
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, &reg32);
        reg32 = (reg32 & hpx->unc_err_mask_and) | hpx->unc_err_mask_or;
        pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, reg32);

        /* Initialize Uncorrectable Error Severity Register */
        pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, &reg32);
        reg32 = (reg32 & hpx->unc_err_sever_and) | hpx->unc_err_sever_or;
        pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, reg32);

        /* Initialize Correctable Error Mask Register */
        pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, &reg32);
        reg32 = (reg32 & hpx->cor_err_mask_and) | hpx->cor_err_mask_or;
        pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, reg32);

        /* Initialize Advanced Error Capabilities and Control Register */
        pci_read_config_dword(dev, pos + PCI_ERR_CAP, &reg32);
        reg32 = (reg32 & hpx->adv_err_cap_and) | hpx->adv_err_cap_or;

        /* Don't enable ECRC generation or checking if unsupported */
        if (!(reg32 & PCI_ERR_CAP_ECRC_GENC))
                reg32 &= ~PCI_ERR_CAP_ECRC_GENE;
        if (!(reg32 & PCI_ERR_CAP_ECRC_CHKC))
                reg32 &= ~PCI_ERR_CAP_ECRC_CHKE;
        pci_write_config_dword(dev, pos + PCI_ERR_CAP, reg32);

        /*
         * FIXME: The following two registers are not supported yet.
         *
         *   o Secondary Uncorrectable Error Severity Register
         *   o Secondary Uncorrectable Error Mask Register
         */
}

static acpi_status decode_type2_hpx_record(union acpi_object *record,
                                           struct hpx_type2 *hpx2)
{
        int i;
        union acpi_object *fields = record->package.elements;
        u32 revision = fields[1].integer.value;

        switch (revision) {
        case 1:
                if (record->package.count != 18)
                        return AE_ERROR;
                for (i = 2; i < 18; i++)
                        if (fields[i].type != ACPI_TYPE_INTEGER)
                                return AE_ERROR;
                hpx2->revision      = revision;
                hpx2->unc_err_mask_and      = fields[2].integer.value;
                hpx2->unc_err_mask_or       = fields[3].integer.value;
                hpx2->unc_err_sever_and     = fields[4].integer.value;
                hpx2->unc_err_sever_or      = fields[5].integer.value;
                hpx2->cor_err_mask_and      = fields[6].integer.value;
                hpx2->cor_err_mask_or       = fields[7].integer.value;
                hpx2->adv_err_cap_and       = fields[8].integer.value;
                hpx2->adv_err_cap_or        = fields[9].integer.value;
                hpx2->pci_exp_devctl_and    = fields[10].integer.value;
                hpx2->pci_exp_devctl_or     = fields[11].integer.value;
                hpx2->pci_exp_lnkctl_and    = fields[12].integer.value;
                hpx2->pci_exp_lnkctl_or     = fields[13].integer.value;
                hpx2->sec_unc_err_sever_and = fields[14].integer.value;
                hpx2->sec_unc_err_sever_or  = fields[15].integer.value;
                hpx2->sec_unc_err_mask_and  = fields[16].integer.value;
                hpx2->sec_unc_err_mask_or   = fields[17].integer.value;
                break;
        default:
                pr_warn("%s: Type 2 Revision %d record not supported\n",
                       __func__, revision);
                return AE_ERROR;
        }
        return AE_OK;
}

/* _HPX PCI Express Setting Record (Type 3) */
struct hpx_type3 {
        u16 device_type;
        u16 function_type;
        u16 config_space_location;
        u16 pci_exp_cap_id;
        u16 pci_exp_cap_ver;
        u16 pci_exp_vendor_id;
        u16 dvsec_id;
        u16 dvsec_rev;
        u16 match_offset;
        u32 match_mask_and;
        u32 match_value;
        u16 reg_offset;
        u32 reg_mask_and;
        u32 reg_mask_or;
};

enum hpx_type3_dev_type {
        HPX_TYPE_ENDPOINT       = BIT(0),
        HPX_TYPE_LEG_END        = BIT(1),
        HPX_TYPE_RC_END         = BIT(2),
        HPX_TYPE_RC_EC          = BIT(3),
        HPX_TYPE_ROOT_PORT      = BIT(4),
        HPX_TYPE_UPSTREAM       = BIT(5),
        HPX_TYPE_DOWNSTREAM     = BIT(6),
        HPX_TYPE_PCI_BRIDGE     = BIT(7),
        HPX_TYPE_PCIE_BRIDGE    = BIT(8),
};

static u16 hpx3_device_type(struct pci_dev *dev)
{
        u16 pcie_type = pci_pcie_type(dev);
        static const int pcie_to_hpx3_type[] = {
                [PCI_EXP_TYPE_ENDPOINT]    = HPX_TYPE_ENDPOINT,
                [PCI_EXP_TYPE_LEG_END]     = HPX_TYPE_LEG_END,
                [PCI_EXP_TYPE_RC_END]      = HPX_TYPE_RC_END,
                [PCI_EXP_TYPE_RC_EC]       = HPX_TYPE_RC_EC,
                [PCI_EXP_TYPE_ROOT_PORT]   = HPX_TYPE_ROOT_PORT,
                [PCI_EXP_TYPE_UPSTREAM]    = HPX_TYPE_UPSTREAM,
                [PCI_EXP_TYPE_DOWNSTREAM]  = HPX_TYPE_DOWNSTREAM,
                [PCI_EXP_TYPE_PCI_BRIDGE]  = HPX_TYPE_PCI_BRIDGE,
                [PCI_EXP_TYPE_PCIE_BRIDGE] = HPX_TYPE_PCIE_BRIDGE,
        };

        if (pcie_type >= ARRAY_SIZE(pcie_to_hpx3_type))
                return 0;

        return pcie_to_hpx3_type[pcie_type];
}

enum hpx_type3_fn_type {
        HPX_FN_NORMAL           = BIT(0),
        HPX_FN_SRIOV_PHYS       = BIT(1),
        HPX_FN_SRIOV_VIRT       = BIT(2),
};

static u8 hpx3_function_type(struct pci_dev *dev)
{
        if (dev->is_virtfn)
                return HPX_FN_SRIOV_VIRT;
        else if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV) > 0)
                return HPX_FN_SRIOV_PHYS;
        else
                return HPX_FN_NORMAL;
}

static bool hpx3_cap_ver_matches(u8 pcie_cap_id, u8 hpx3_cap_id)
{
        u8 cap_ver = hpx3_cap_id & 0xf;

        if ((hpx3_cap_id & BIT(4)) && cap_ver >= pcie_cap_id)
                return true;
        else if (cap_ver == pcie_cap_id)
                return true;

        return false;
}

enum hpx_type3_cfg_loc {
        HPX_CFG_PCICFG          = 0,
        HPX_CFG_PCIE_CAP        = 1,
        HPX_CFG_PCIE_CAP_EXT    = 2,
        HPX_CFG_VEND_CAP        = 3,
        HPX_CFG_DVSEC           = 4,
        HPX_CFG_MAX,
};

static void program_hpx_type3_register(struct pci_dev *dev,
                                       const struct hpx_type3 *reg)
{
        u32 match_reg, write_reg, header, orig_value;
        u16 pos;

        if (!(hpx3_device_type(dev) & reg->device_type))
                return;

        if (!(hpx3_function_type(dev) & reg->function_type))
                return;

        switch (reg->config_space_location) {
        case HPX_CFG_PCICFG:
                pos = 0;
                break;
        case HPX_CFG_PCIE_CAP:
                pos = pci_find_capability(dev, reg->pci_exp_cap_id);
                if (pos == 0)
                        return;

                break;
        case HPX_CFG_PCIE_CAP_EXT:
                pos = pci_find_ext_capability(dev, reg->pci_exp_cap_id);
                if (pos == 0)
                        return;

                pci_read_config_dword(dev, pos, &header);
                if (!hpx3_cap_ver_matches(PCI_EXT_CAP_VER(header),
                                          reg->pci_exp_cap_ver))
                        return;

                break;
        case HPX_CFG_VEND_CAP:
        case HPX_CFG_DVSEC:
        default:
                pci_warn(dev, "Encountered _HPX type 3 with unsupported config space location");
                return;
        }

        pci_read_config_dword(dev, pos + reg->match_offset, &match_reg);

        if ((match_reg & reg->match_mask_and) != reg->match_value)
                return;

        pci_read_config_dword(dev, pos + reg->reg_offset, &write_reg);
        orig_value = write_reg;
        write_reg &= reg->reg_mask_and;
        write_reg |= reg->reg_mask_or;

        if (orig_value == write_reg)
                return;

        pci_write_config_dword(dev, pos + reg->reg_offset, write_reg);

        pci_dbg(dev, "Applied _HPX3 at [0x%x]: 0x%08x -> 0x%08x",
                pos, orig_value, write_reg);
}

static void program_hpx_type3(struct pci_dev *dev, struct hpx_type3 *hpx)
{
        if (!hpx)
                return;

        if (!pci_is_pcie(dev))
                return;

        program_hpx_type3_register(dev, hpx);
}

static void parse_hpx3_register(struct hpx_type3 *hpx3_reg,
                                union acpi_object *reg_fields)
{
        hpx3_reg->device_type            = reg_fields[0].integer.value;
        hpx3_reg->function_type          = reg_fields[1].integer.value;
        hpx3_reg->config_space_location  = reg_fields[2].integer.value;
        hpx3_reg->pci_exp_cap_id         = reg_fields[3].integer.value;
        hpx3_reg->pci_exp_cap_ver        = reg_fields[4].integer.value;
        hpx3_reg->pci_exp_vendor_id      = reg_fields[5].integer.value;
        hpx3_reg->dvsec_id               = reg_fields[6].integer.value;
        hpx3_reg->dvsec_rev              = reg_fields[7].integer.value;
        hpx3_reg->match_offset           = reg_fields[8].integer.value;
        hpx3_reg->match_mask_and         = reg_fields[9].integer.value;
        hpx3_reg->match_value            = reg_fields[10].integer.value;
        hpx3_reg->reg_offset             = reg_fields[11].integer.value;
        hpx3_reg->reg_mask_and           = reg_fields[12].integer.value;
        hpx3_reg->reg_mask_or            = reg_fields[13].integer.value;
}

static acpi_status program_type3_hpx_record(struct pci_dev *dev,
                                           union acpi_object *record)
{
        union acpi_object *fields = record->package.elements;
        u32 desc_count, expected_length, revision;
        union acpi_object *reg_fields;
        struct hpx_type3 hpx3;
        int i;

        revision = fields[1].integer.value;
        switch (revision) {
        case 1:
                desc_count = fields[2].integer.value;
                expected_length = 3 + desc_count * 14;

                if (record->package.count != expected_length)
                        return AE_ERROR;

                for (i = 2; i < expected_length; i++)
                        if (fields[i].type != ACPI_TYPE_INTEGER)
                                return AE_ERROR;

                for (i = 0; i < desc_count; i++) {
                        reg_fields = fields + 3 + i * 14;
                        parse_hpx3_register(&hpx3, reg_fields);
                        program_hpx_type3(dev, &hpx3);
                }

                break;
        default:
                printk(KERN_WARNING
                        "%s: Type 3 Revision %d record not supported\n",
                        __func__, revision);
                return AE_ERROR;
        }
        return AE_OK;
}

static acpi_status acpi_run_hpx(struct pci_dev *dev, acpi_handle handle)
{
        acpi_status status;
        struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
        union acpi_object *package, *record, *fields;
        struct hpx_type0 hpx0;
        struct hpx_type1 hpx1;
        struct hpx_type2 hpx2;
        u32 type;
        int i;

        status = acpi_evaluate_object(handle, "_HPX", NULL, &buffer);
        if (ACPI_FAILURE(status))
                return status;

        package = (union acpi_object *)buffer.pointer;
        if (package->type != ACPI_TYPE_PACKAGE) {
                status = AE_ERROR;
                goto exit;
        }

        for (i = 0; i < package->package.count; i++) {
                record = &package->package.elements[i];
                if (record->type != ACPI_TYPE_PACKAGE) {
                        status = AE_ERROR;
                        goto exit;
                }

                fields = record->package.elements;
                if (fields[0].type != ACPI_TYPE_INTEGER ||
                    fields[1].type != ACPI_TYPE_INTEGER) {
                        status = AE_ERROR;
                        goto exit;
                }

                type = fields[0].integer.value;
                switch (type) {
                case 0:
                        memset(&hpx0, 0, sizeof(hpx0));
                        status = decode_type0_hpx_record(record, &hpx0);
                        if (ACPI_FAILURE(status))
                                goto exit;
                        program_hpx_type0(dev, &hpx0);
                        break;
                case 1:
                        memset(&hpx1, 0, sizeof(hpx1));
                        status = decode_type1_hpx_record(record, &hpx1);
                        if (ACPI_FAILURE(status))
                                goto exit;
                        program_hpx_type1(dev, &hpx1);
                        break;
                case 2:
                        memset(&hpx2, 0, sizeof(hpx2));
                        status = decode_type2_hpx_record(record, &hpx2);
                        if (ACPI_FAILURE(status))
                                goto exit;
                        program_hpx_type2(dev, &hpx2);
                        break;
                case 3:
                        status = program_type3_hpx_record(dev, record);
                        if (ACPI_FAILURE(status))
                                goto exit;
                        break;
                default:
                        pr_err("%s: Type %d record not supported\n",
                               __func__, type);
                        status = AE_ERROR;
                        goto exit;
                }
        }
 exit:
        kfree(buffer.pointer);
        return status;
}

static acpi_status acpi_run_hpp(struct pci_dev *dev, acpi_handle handle)
{
        acpi_status status;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *package, *fields;
        struct hpx_type0 hpx0;
        int i;

        memset(&hpx0, 0, sizeof(hpx0));

        status = acpi_evaluate_object(handle, "_HPP", NULL, &buffer);
        if (ACPI_FAILURE(status))
                return status;

        package = (union acpi_object *) buffer.pointer;
        if (package->type != ACPI_TYPE_PACKAGE ||
            package->package.count != 4) {
                status = AE_ERROR;
                goto exit;
        }

        fields = package->package.elements;
        for (i = 0; i < 4; i++) {
                if (fields[i].type != ACPI_TYPE_INTEGER) {
                        status = AE_ERROR;
                        goto exit;
                }
        }

        hpx0.revision        = 1;
        hpx0.cache_line_size = fields[0].integer.value;
        hpx0.latency_timer   = fields[1].integer.value;
        hpx0.enable_serr     = fields[2].integer.value;
        hpx0.enable_perr     = fields[3].integer.value;

        program_hpx_type0(dev, &hpx0);

exit:
        kfree(buffer.pointer);
        return status;
}

/* pci_acpi_program_hp_params
 *
 * @dev - the pci_dev for which we want parameters
 */
int pci_acpi_program_hp_params(struct pci_dev *dev)
{
        acpi_status status;
        acpi_handle handle, phandle;
        struct pci_bus *pbus;

        if (acpi_pci_disabled)
                return -ENODEV;

        handle = NULL;
        for (pbus = dev->bus; pbus; pbus = pbus->parent) {
                handle = acpi_pci_get_bridge_handle(pbus);
                if (handle)
                        break;
        }

        /*
         * _HPP settings apply to all child buses, until another _HPP is
         * encountered. If we don't find an _HPP for the input pci dev,
         * look for it in the parent device scope since that would apply to
         * this pci dev.
         */
        while (handle) {
                status = acpi_run_hpx(dev, handle);
                if (ACPI_SUCCESS(status))
                        return 0;
                status = acpi_run_hpp(dev, handle);
                if (ACPI_SUCCESS(status))
                        return 0;
                if (acpi_is_root_bridge(handle))
                        break;
                status = acpi_get_parent(handle, &phandle);
                if (ACPI_FAILURE(status))
                        break;
                handle = phandle;
        }
        return -ENODEV;
}

/**
 * pciehp_is_native - Check whether a hotplug port is handled by the OS
 * @bridge: Hotplug port to check
 *
 * Returns true if the given @bridge is handled by the native PCIe hotplug
 * driver.
 */
bool pciehp_is_native(struct pci_dev *bridge)
{
        const struct pci_host_bridge *host;
        u32 slot_cap;

        if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE))
                return false;

        pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap);
        if (!(slot_cap & PCI_EXP_SLTCAP_HPC))
                return false;

        if (pcie_ports_native)
                return true;

        host = pci_find_host_bridge(bridge->bus);
        return host->native_pcie_hotplug;
}

/**
 * shpchp_is_native - Check whether a hotplug port is handled by the OS
 * @bridge: Hotplug port to check
 *
 * Returns true if the given @bridge is handled by the native SHPC hotplug
 * driver.
 */
bool shpchp_is_native(struct pci_dev *bridge)
{
        return bridge->shpc_managed;
}

/**
 * pci_acpi_wake_bus - Root bus wakeup notification fork function.
 * @context: Device wakeup context.
 */
static void pci_acpi_wake_bus(struct acpi_device_wakeup_context *context)
{
        struct acpi_device *adev;
        struct acpi_pci_root *root;

        adev = container_of(context, struct acpi_device, wakeup.context);
        root = acpi_driver_data(adev);
        pci_pme_wakeup_bus(root->bus);
}

/**
 * pci_acpi_wake_dev - PCI device wakeup notification work function.
 * @context: Device wakeup context.
 */
static void pci_acpi_wake_dev(struct acpi_device_wakeup_context *context)
{
        struct pci_dev *pci_dev;

        pci_dev = to_pci_dev(context->dev);

        if (pci_dev->pme_poll)
                pci_dev->pme_poll = false;

        if (pci_dev->current_state == PCI_D3cold) {
                pci_wakeup_event(pci_dev);
                pm_request_resume(&pci_dev->dev);
                return;
        }

        /* Clear PME Status if set. */
        if (pci_dev->pme_support)
                pci_check_pme_status(pci_dev);

        pci_wakeup_event(pci_dev);
        pm_request_resume(&pci_dev->dev);

        pci_pme_wakeup_bus(pci_dev->subordinate);
}

/**
 * pci_acpi_add_bus_pm_notifier - Register PM notifier for root PCI bus.
 * @dev: PCI root bridge ACPI device.
 */
acpi_status pci_acpi_add_bus_pm_notifier(struct acpi_device *dev)
{
        return acpi_add_pm_notifier(dev, NULL, pci_acpi_wake_bus);
}

/**
 * pci_acpi_add_pm_notifier - Register PM notifier for given PCI device.
 * @dev: ACPI device to add the notifier for.
 * @pci_dev: PCI device to check for the PME status if an event is signaled.
 */
acpi_status pci_acpi_add_pm_notifier(struct acpi_device *dev,
                                     struct pci_dev *pci_dev)
{
        return acpi_add_pm_notifier(dev, &pci_dev->dev, pci_acpi_wake_dev);
}

/*
 * _SxD returns the D-state with the highest power
 * (lowest D-state number) supported in the S-state "x".
 *
 * If the devices does not have a _PRW
 * (Power Resources for Wake) supporting system wakeup from "x"
 * then the OS is free to choose a lower power (higher number
 * D-state) than the return value from _SxD.
 *
 * But if _PRW is enabled at S-state "x", the OS
 * must not choose a power lower than _SxD --
 * unless the device has an _SxW method specifying
 * the lowest power (highest D-state number) the device
 * may enter while still able to wake the system.
 *
 * ie. depending on global OS policy:
 *
 * if (_PRW at S-state x)
 *      choose from highest power _SxD to lowest power _SxW
 * else // no _PRW at S-state x
 *      choose highest power _SxD or any lower power
 */

static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
{
        int acpi_state, d_max;

        if (pdev->no_d3cold)
                d_max = ACPI_STATE_D3_HOT;
        else
                d_max = ACPI_STATE_D3_COLD;
        acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL, d_max);
        if (acpi_state < 0)
                return PCI_POWER_ERROR;

        switch (acpi_state) {
        case ACPI_STATE_D0:
                return PCI_D0;
        case ACPI_STATE_D1:
                return PCI_D1;
        case ACPI_STATE_D2:
                return PCI_D2;
        case ACPI_STATE_D3_HOT:
                return PCI_D3hot;
        case ACPI_STATE_D3_COLD:
                return PCI_D3cold;
        }
        return PCI_POWER_ERROR;
}

static struct acpi_device *acpi_pci_find_companion(struct device *dev);

void pci_set_acpi_fwnode(struct pci_dev *dev)
{
        if (!dev_fwnode(&dev->dev) && !pci_dev_is_added(dev))
                ACPI_COMPANION_SET(&dev->dev,
                                   acpi_pci_find_companion(&dev->dev));
}

/**
 * pci_dev_acpi_reset - do a function level reset using _RST method
 * @dev: device to reset
 * @probe: if true, return 0 if device supports _RST
 */
int pci_dev_acpi_reset(struct pci_dev *dev, bool probe)
{
        acpi_handle handle = ACPI_HANDLE(&dev->dev);

        if (!handle || !acpi_has_method(handle, "_RST"))
                return -ENOTTY;

        if (probe)
                return 0;

        if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) {
                pci_warn(dev, "ACPI _RST failed\n");
                return -ENOTTY;
        }

        return 0;
}

static bool acpi_pci_power_manageable(struct pci_dev *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(&dev->dev);

        if (!adev)
                return false;
        return acpi_device_power_manageable(adev);
}

static bool acpi_pci_bridge_d3(struct pci_dev *dev)
{
        const union acpi_object *obj;
        struct acpi_device *adev;
        struct pci_dev *rpdev;

        if (!dev->is_hotplug_bridge)
                return false;

        /* Assume D3 support if the bridge is power-manageable by ACPI. */
        if (acpi_pci_power_manageable(dev))
                return true;

        /*
         * The ACPI firmware will provide the device-specific properties through
         * _DSD configuration object. Look for the 'HotPlugSupportInD3' property
         * for the root port and if it is set we know the hierarchy behind it
         * supports D3 just fine.
         */
        rpdev = pcie_find_root_port(dev);
        if (!rpdev)
                return false;

        adev = ACPI_COMPANION(&rpdev->dev);

        if (!adev)
                return false;

        if (acpi_dev_get_property(adev, "HotPlugSupportInD3",
                                   ACPI_TYPE_INTEGER, &obj) < 0)
                return false;

        return obj->integer.value == 1;
}

static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
{
        struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
        static const u8 state_conv[] = {
                [PCI_D0] = ACPI_STATE_D0,
                [PCI_D1] = ACPI_STATE_D1,
                [PCI_D2] = ACPI_STATE_D2,
                [PCI_D3hot] = ACPI_STATE_D3_HOT,
                [PCI_D3cold] = ACPI_STATE_D3_COLD,
        };
        int error = -EINVAL;

        /* If the ACPI device has _EJ0, ignore the device */
        if (!adev || acpi_has_method(adev->handle, "_EJ0"))
                return -ENODEV;

        switch (state) {
        case PCI_D3cold:
                if (dev_pm_qos_flags(&dev->dev, PM_QOS_FLAG_NO_POWER_OFF) ==
                                PM_QOS_FLAGS_ALL) {
                        error = -EBUSY;
                        break;
                }
                fallthrough;
        case PCI_D0:
        case PCI_D1:
        case PCI_D2:
        case PCI_D3hot:
                error = acpi_device_set_power(adev, state_conv[state]);
        }

        if (!error)
                pci_dbg(dev, "power state changed by ACPI to %s\n",
                        acpi_power_state_string(adev->power.state));

        return error;
}

static pci_power_t acpi_pci_get_power_state(struct pci_dev *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
        static const pci_power_t state_conv[] = {
                [ACPI_STATE_D0]      = PCI_D0,
                [ACPI_STATE_D1]      = PCI_D1,
                [ACPI_STATE_D2]      = PCI_D2,
                [ACPI_STATE_D3_HOT]  = PCI_D3hot,
                [ACPI_STATE_D3_COLD] = PCI_D3cold,
        };
        int state;

        if (!adev || !acpi_device_power_manageable(adev))
                return PCI_UNKNOWN;

        state = adev->power.state;
        if (state == ACPI_STATE_UNKNOWN)
                return PCI_UNKNOWN;

        return state_conv[state];
}

static void acpi_pci_refresh_power_state(struct pci_dev *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(&dev->dev);

        if (adev && acpi_device_power_manageable(adev))
                acpi_device_update_power(adev, NULL);
}

static int acpi_pci_propagate_wakeup(struct pci_bus *bus, bool enable)
{
        while (bus->parent) {
                if (acpi_pm_device_can_wakeup(&bus->self->dev))
                        return acpi_pm_set_device_wakeup(&bus->self->dev, enable);

                bus = bus->parent;
        }

        /* We have reached the root bus. */
        if (bus->bridge) {
                if (acpi_pm_device_can_wakeup(bus->bridge))
                        return acpi_pm_set_device_wakeup(bus->bridge, enable);
        }
        return 0;
}

static int acpi_pci_wakeup(struct pci_dev *dev, bool enable)
{
        if (acpi_pm_device_can_wakeup(&dev->dev))
                return acpi_pm_set_device_wakeup(&dev->dev, enable);

        return acpi_pci_propagate_wakeup(dev->bus, enable);
}

static bool acpi_pci_need_resume(struct pci_dev *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(&dev->dev);

        /*
         * In some cases (eg. Samsung 305V4A) leaving a bridge in suspend over
         * system-wide suspend/resume confuses the platform firmware, so avoid
         * doing that.  According to Section 16.1.6 of ACPI 6.2, endpoint
         * devices are expected to be in D3 before invoking the S3 entry path
         * from the firmware, so they should not be affected by this issue.
         */
        if (pci_is_bridge(dev) && acpi_target_system_state() != ACPI_STATE_S0)
                return true;

        if (!adev || !acpi_device_power_manageable(adev))
                return false;

        if (adev->wakeup.flags.valid &&
            device_may_wakeup(&dev->dev) != !!adev->wakeup.prepare_count)
                return true;

        if (acpi_target_system_state() == ACPI_STATE_S0)
                return false;

        return !!adev->power.flags.dsw_present;
}

static const struct pci_platform_pm_ops acpi_pci_platform_pm = {
        .bridge_d3 = acpi_pci_bridge_d3,
        .is_manageable = acpi_pci_power_manageable,
        .set_state = acpi_pci_set_power_state,
        .get_state = acpi_pci_get_power_state,
        .refresh_state = acpi_pci_refresh_power_state,
        .choose_state = acpi_pci_choose_state,
        .set_wakeup = acpi_pci_wakeup,
        .need_resume = acpi_pci_need_resume,
};

void acpi_pci_add_bus(struct pci_bus *bus)
{
        union acpi_object *obj;
        struct pci_host_bridge *bridge;

        if (acpi_pci_disabled || !bus->bridge || !ACPI_HANDLE(bus->bridge))
                return;

        acpi_pci_slot_enumerate(bus);
        acpiphp_enumerate_slots(bus);

        /*
         * For a host bridge, check its _DSM for function 8 and if
         * that is available, mark it in pci_host_bridge.
         */
        if (!pci_is_root_bus(bus))
                return;

        obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 3,
                                DSM_PCI_POWER_ON_RESET_DELAY, NULL);
        if (!obj)
                return;

        if (obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 1) {
                bridge = pci_find_host_bridge(bus);
                bridge->ignore_reset_delay = 1;
        }
        ACPI_FREE(obj);
}

void acpi_pci_remove_bus(struct pci_bus *bus)
{
        if (acpi_pci_disabled || !bus->bridge)
                return;

        acpiphp_remove_slots(bus);
        acpi_pci_slot_remove(bus);
}

/* ACPI bus type */


static DECLARE_RWSEM(pci_acpi_companion_lookup_sem);
static struct acpi_device *(*pci_acpi_find_companion_hook)(struct pci_dev *);

/**
 * pci_acpi_set_companion_lookup_hook - Set ACPI companion lookup callback.
 * @func: ACPI companion lookup callback pointer or NULL.
 *
 * Set a special ACPI companion lookup callback for PCI devices whose companion
 * objects in the ACPI namespace have _ADR with non-standard bus-device-function
 * encodings.
 *
 * Return 0 on success or a negative error code on failure (in which case no
 * changes are made).
 *
 * The caller is responsible for the appropriate ordering of the invocations of
 * this function with respect to the enumeration of the PCI devices needing the
 * callback installed by it.
 */
int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *))
{
        int ret;

        if (!func)
                return -EINVAL;

        down_write(&pci_acpi_companion_lookup_sem);

        if (pci_acpi_find_companion_hook) {
                ret = -EBUSY;
        } else {
                pci_acpi_find_companion_hook = func;
                ret = 0;
        }

        up_write(&pci_acpi_companion_lookup_sem);

        return ret;
}
EXPORT_SYMBOL_GPL(pci_acpi_set_companion_lookup_hook);

/**
 * pci_acpi_clear_companion_lookup_hook - Clear ACPI companion lookup callback.
 *
 * Clear the special ACPI companion lookup callback previously set by
 * pci_acpi_set_companion_lookup_hook().  Block until the last running instance
 * of the callback returns before clearing it.
 *
 * The caller is responsible for the appropriate ordering of the invocations of
 * this function with respect to the enumeration of the PCI devices needing the
 * callback cleared by it.
 */
void pci_acpi_clear_companion_lookup_hook(void)
{
        down_write(&pci_acpi_companion_lookup_sem);

        pci_acpi_find_companion_hook = NULL;

        up_write(&pci_acpi_companion_lookup_sem);
}
EXPORT_SYMBOL_GPL(pci_acpi_clear_companion_lookup_hook);

static struct acpi_device *acpi_pci_find_companion(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        struct acpi_device *adev;
        bool check_children;
        u64 addr;

        if (!dev->parent)
                return NULL;

        down_read(&pci_acpi_companion_lookup_sem);

        adev = pci_acpi_find_companion_hook ?
                pci_acpi_find_companion_hook(pci_dev) : NULL;

        up_read(&pci_acpi_companion_lookup_sem);

        if (adev)
                return adev;

        check_children = pci_is_bridge(pci_dev);
        /* Please ref to ACPI spec for the syntax of _ADR */
        addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
        adev = acpi_find_child_device(ACPI_COMPANION(dev->parent), addr,
                                      check_children);

        /*
         * There may be ACPI device objects in the ACPI namespace that are
         * children of the device object representing the host bridge, but don't
         * represent PCI devices.  Both _HID and _ADR may be present for them,
         * even though that is against the specification (for example, see
         * Section 6.1 of ACPI 6.3), but in many cases the _ADR returns 0 which
         * appears to indicate that they should not be taken into consideration
         * as potential companions of PCI devices on the root bus.
         *
         * To catch this special case, disregard the returned device object if
         * it has a valid _HID, addr is 0 and the PCI device at hand is on the
         * root bus.
         */
        if (adev && adev->pnp.type.platform_id && !addr &&
            pci_is_root_bus(pci_dev->bus))
                return NULL;

        return adev;
}

/**
 * pci_acpi_optimize_delay - optimize PCI D3 and D3cold delay from ACPI
 * @pdev: the PCI device whose delay is to be updated
 * @handle: ACPI handle of this device
 *
 * Update the d3hot_delay and d3cold_delay of a PCI device from the ACPI _DSM
 * control method of either the device itself or the PCI host bridge.
 *
 * Function 8, "Reset Delay," applies to the entire hierarchy below a PCI
 * host bridge.  If it returns one, the OS may assume that all devices in
 * the hierarchy have already completed power-on reset delays.
 *
 * Function 9, "Device Readiness Durations," applies only to the object
 * where it is located.  It returns delay durations required after various
 * events if the device requires less time than the spec requires.  Delays
 * from this function take precedence over the Reset Delay function.
 *
 * These _DSM functions are defined by the draft ECN of January 28, 2014,
 * titled "ACPI additions for FW latency optimizations."
 */
static void pci_acpi_optimize_delay(struct pci_dev *pdev,
                                    acpi_handle handle)
{
        struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);
        int value;
        union acpi_object *obj, *elements;

        if (bridge->ignore_reset_delay)
                pdev->d3cold_delay = 0;

        obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 3,
                                DSM_PCI_DEVICE_READINESS_DURATIONS, NULL);
        if (!obj)
                return;

        if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 5) {
                elements = obj->package.elements;
                if (elements[0].type == ACPI_TYPE_INTEGER) {
                        value = (int)elements[0].integer.value / 1000;
                        if (value < PCI_PM_D3COLD_WAIT)
                                pdev->d3cold_delay = value;
                }
                if (elements[3].type == ACPI_TYPE_INTEGER) {
                        value = (int)elements[3].integer.value / 1000;
                        if (value < PCI_PM_D3HOT_WAIT)
                                pdev->d3hot_delay = value;
                }
        }
        ACPI_FREE(obj);
}

static void pci_acpi_set_external_facing(struct pci_dev *dev)
{
        u8 val;

        if (pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT)
                return;
        if (device_property_read_u8(&dev->dev, "ExternalFacingPort", &val))
                return;

        /*
         * These root ports expose PCIe (including DMA) outside of the
         * system.  Everything downstream from them is external.
         */
        if (val)
                dev->external_facing = 1;
}

static void pci_acpi_setup(struct device *dev)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        struct acpi_device *adev = ACPI_COMPANION(dev);

        if (!adev)
                return;

        pci_acpi_optimize_delay(pci_dev, adev->handle);
        pci_acpi_set_external_facing(pci_dev);
        pci_acpi_add_edr_notifier(pci_dev);

        pci_acpi_add_pm_notifier(adev, pci_dev);
        if (!adev->wakeup.flags.valid)
                return;

        device_set_wakeup_capable(dev, true);
        /*
         * For bridges that can do D3 we enable wake automatically (as
         * we do for the power management itself in that case). The
         * reason is that the bridge may have additional methods such as
         * _DSW that need to be called.
         */
        if (pci_dev->bridge_d3)
                device_wakeup_enable(dev);

        acpi_pci_wakeup(pci_dev, false);
        acpi_device_power_add_dependent(adev, dev);
}

static void pci_acpi_cleanup(struct device *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);
        struct pci_dev *pci_dev = to_pci_dev(dev);

        if (!adev)
                return;

        pci_acpi_remove_edr_notifier(pci_dev);
        pci_acpi_remove_pm_notifier(adev);
        if (adev->wakeup.flags.valid) {
                acpi_device_power_remove_dependent(adev, dev);
                if (pci_dev->bridge_d3)
                        device_wakeup_disable(dev);

                device_set_wakeup_capable(dev, false);
        }
}

static bool pci_acpi_bus_match(struct device *dev)
{
        return dev_is_pci(dev);
}

static struct acpi_bus_type acpi_pci_bus = {
        .name = "PCI",
        .match = pci_acpi_bus_match,
        .find_companion = acpi_pci_find_companion,
        .setup = pci_acpi_setup,
        .cleanup = pci_acpi_cleanup,
};


static struct fwnode_handle *(*pci_msi_get_fwnode_cb)(struct device *dev);

/**
 * pci_msi_register_fwnode_provider - Register callback to retrieve fwnode
 * @fn:       Callback matching a device to a fwnode that identifies a PCI
 *            MSI domain.
 *
 * This should be called by irqchip driver, which is the parent of
 * the MSI domain to provide callback interface to query fwnode.
 */
void
pci_msi_register_fwnode_provider(struct fwnode_handle *(*fn)(struct device *))
{
        pci_msi_get_fwnode_cb = fn;
}

/**
 * pci_host_bridge_acpi_msi_domain - Retrieve MSI domain of a PCI host bridge
 * @bus:      The PCI host bridge bus.
 *
 * This function uses the callback function registered by
 * pci_msi_register_fwnode_provider() to retrieve the irq_domain with
 * type DOMAIN_BUS_PCI_MSI of the specified host bridge bus.
 * This returns NULL on error or when the domain is not found.
 */
struct irq_domain *pci_host_bridge_acpi_msi_domain(struct pci_bus *bus)
{
        struct fwnode_handle *fwnode;

        if (!pci_msi_get_fwnode_cb)
                return NULL;

        fwnode = pci_msi_get_fwnode_cb(&bus->dev);
        if (!fwnode)
                return NULL;

        return irq_find_matching_fwnode(fwnode, DOMAIN_BUS_PCI_MSI);
}

static int __init acpi_pci_init(void)
{
        int ret;

        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_MSI) {
                pr_info("ACPI FADT declares the system doesn't support MSI, so disable it\n");
                pci_no_msi();
        }

        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
                pr_info("ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
                pcie_no_aspm();
        }

        ret = register_acpi_bus_type(&acpi_pci_bus);
        if (ret)
                return 0;

        pci_set_platform_pm(&acpi_pci_platform_pm);
        acpi_pci_slot_init();
        acpiphp_init();

        return 0;
}
arch_initcall(acpi_pci_init);