// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
 *
 * TBD:
 *      1. Support more than one IRQ resource entry per link device (index).
 *      2. Implement start/stop mechanism and use ACPI Bus Driver facilities
 *         for IRQ management (e.g. start()->_SRS).
 */

#define pr_fmt(fmt) "ACPI: PCI: " fmt

#include <linux/syscore_ops.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/pm.h>
#include <linux/pci.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/irq.h>

#include "internal.h"

#define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
#define ACPI_PCI_LINK_DEVICE_NAME       "PCI Interrupt Link"
#define ACPI_PCI_LINK_MAX_POSSIBLE      16

static int acpi_pci_link_add(struct acpi_device *device,
                             const struct acpi_device_id *not_used);
static void acpi_pci_link_remove(struct acpi_device *device);

static const struct acpi_device_id link_device_ids[] = {
        {"PNP0C0F", 0},
        {"", 0},
};

static struct acpi_scan_handler pci_link_handler = {
        .ids = link_device_ids,
        .attach = acpi_pci_link_add,
        .detach = acpi_pci_link_remove,
};

/*
 * If a link is initialized, we never change its active and initialized
 * later even the link is disable. Instead, we just repick the active irq
 */
struct acpi_pci_link_irq {
        u32 active;             /* Current IRQ */
        u8 triggering;          /* All IRQs */
        u8 polarity;            /* All IRQs */
        u8 resource_type;
        u8 possible_count;
        u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
        u8 initialized:1;
        u8 reserved:7;
};

struct acpi_pci_link {
        struct list_head                list;
        struct acpi_device              *device;
        struct acpi_pci_link_irq        irq;
        int                             refcnt;
};

static LIST_HEAD(acpi_link_list);
static DEFINE_MUTEX(acpi_link_lock);
static int sci_irq = -1, sci_penalty;

/* --------------------------------------------------------------------------
                            PCI Link Device Management
   -------------------------------------------------------------------------- */

/*
 * set context (link) possible list from resource list
 */
static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
                                                void *context)
{
        struct acpi_pci_link *link = context;
        acpi_handle handle = link->device->handle;
        u32 i;

        switch (resource->type) {
        case ACPI_RESOURCE_TYPE_START_DEPENDENT:
        case ACPI_RESOURCE_TYPE_END_TAG:
                return AE_OK;
        case ACPI_RESOURCE_TYPE_IRQ:
                {
                        struct acpi_resource_irq *p = &resource->data.irq;
                        if (!p->interrupt_count) {
                                acpi_handle_debug(handle,
                                                  "Blank _PRS IRQ resource\n");
                                return AE_OK;
                        }
                        for (i = 0;
                             (i < p->interrupt_count
                              && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
                                if (!p->interrupts[i]) {
                                        acpi_handle_debug(handle,
                                                          "Invalid _PRS IRQ %d\n",
                                                          p->interrupts[i]);
                                        continue;
                                }
                                link->irq.possible[i] = p->interrupts[i];
                                link->irq.possible_count++;
                        }
                        link->irq.triggering = p->triggering;
                        link->irq.polarity = p->polarity;
                        link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
                        break;
                }
        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
                {
                        struct acpi_resource_extended_irq *p =
                            &resource->data.extended_irq;
                        if (!p->interrupt_count) {
                                acpi_handle_debug(handle,
                                                  "Blank _PRS EXT IRQ resource\n");
                                return AE_OK;
                        }
                        for (i = 0;
                             (i < p->interrupt_count
                              && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
                                if (!p->interrupts[i]) {
                                        acpi_handle_debug(handle,
                                                          "Invalid _PRS IRQ %d\n",
                                                          p->interrupts[i]);
                                        continue;
                                }
                                link->irq.possible[i] = p->interrupts[i];
                                link->irq.possible_count++;
                        }
                        link->irq.triggering = p->triggering;
                        link->irq.polarity = p->polarity;
                        link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
                        break;
                }
        default:
                acpi_handle_debug(handle, "_PRS resource type 0x%x is not IRQ\n",
                                  resource->type);
                return AE_OK;
        }

        return AE_CTRL_TERMINATE;
}

static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
{
        acpi_handle handle = link->device->handle;
        acpi_status status;

        status = acpi_walk_resources(handle, METHOD_NAME__PRS,
                                     acpi_pci_link_check_possible, link);
        if (ACPI_FAILURE(status)) {
                acpi_handle_debug(handle, "_PRS not present or invalid");
                return 0;
        }

        acpi_handle_debug(handle, "Found %d possible IRQs\n",
                          link->irq.possible_count);

        return 0;
}

static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
                                               void *context)
{
        int *irq = context;

        switch (resource->type) {
        case ACPI_RESOURCE_TYPE_START_DEPENDENT:
        case ACPI_RESOURCE_TYPE_END_TAG:
                return AE_OK;
        case ACPI_RESOURCE_TYPE_IRQ:
                {
                        struct acpi_resource_irq *p = &resource->data.irq;
                        if (!p->interrupt_count) {
                                /*
                                 * IRQ descriptors may have no IRQ# bits set,
                                 * particularly those w/ _STA disabled
                                 */
                                pr_debug("Blank _CRS IRQ resource\n");
                                return AE_OK;
                        }
                        *irq = p->interrupts[0];
                        break;
                }
        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
                {
                        struct acpi_resource_extended_irq *p =
                            &resource->data.extended_irq;
                        if (!p->interrupt_count) {
                                /*
                                 * extended IRQ descriptors must
                                 * return at least 1 IRQ
                                 */
                                pr_debug("Blank _CRS EXT IRQ resource\n");
                                return AE_OK;
                        }
                        *irq = p->interrupts[0];
                        break;
                }
                break;
        default:
                pr_debug("_CRS resource type 0x%x is not IRQ\n",
                         resource->type);
                return AE_OK;
        }

        return AE_CTRL_TERMINATE;
}

/*
 * Run _CRS and set link->irq.active
 *
 * return value:
 * 0 - success
 * !0 - failure
 */
static int acpi_pci_link_get_current(struct acpi_pci_link *link)
{
        acpi_handle handle = link->device->handle;
        acpi_status status;
        int result = 0;
        int irq = 0;

        link->irq.active = 0;

        /* in practice, status disabled is meaningless, ignore it */
        if (acpi_strict) {
                /* Query _STA, set link->device->status */
                result = acpi_bus_get_status(link->device);
                if (result) {
                        acpi_handle_err(handle, "Unable to read status\n");
                        goto end;
                }

                if (!link->device->status.enabled) {
                        acpi_handle_debug(handle, "Link disabled\n");
                        return 0;
                }
        }

        /*
         * Query and parse _CRS to get the current IRQ assignment.
         */

        status = acpi_walk_resources(handle, METHOD_NAME__CRS,
                                     acpi_pci_link_check_current, &irq);
        if (ACPI_FAILURE(status)) {
                acpi_evaluation_failure_warn(handle, "_CRS", status);
                result = -ENODEV;
                goto end;
        }

        if (acpi_strict && !irq) {
                acpi_handle_err(handle, "_CRS returned 0\n");
                result = -ENODEV;
        }

        link->irq.active = irq;

        acpi_handle_debug(handle, "Link at IRQ %d\n", link->irq.active);

      end:
        return result;
}

static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
{
        struct {
                struct acpi_resource res;
                struct acpi_resource end;
        } *resource;
        struct acpi_buffer buffer = { 0, NULL };
        acpi_handle handle = link->device->handle;
        acpi_status status;
        int result;

        if (!irq)
                return -EINVAL;

        resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
        if (!resource)
                return -ENOMEM;

        buffer.length = sizeof(*resource) + 1;
        buffer.pointer = resource;

        switch (link->irq.resource_type) {
        case ACPI_RESOURCE_TYPE_IRQ:
                resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
                resource->res.length = sizeof(struct acpi_resource);
                resource->res.data.irq.triggering = link->irq.triggering;
                resource->res.data.irq.polarity =
                    link->irq.polarity;
                if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
                        resource->res.data.irq.shareable =
                            ACPI_EXCLUSIVE;
                else
                        resource->res.data.irq.shareable = ACPI_SHARED;
                resource->res.data.irq.interrupt_count = 1;
                resource->res.data.irq.interrupts[0] = irq;
                break;

        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
                resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
                resource->res.length = sizeof(struct acpi_resource);
                resource->res.data.extended_irq.producer_consumer =
                    ACPI_CONSUMER;
                resource->res.data.extended_irq.triggering =
                    link->irq.triggering;
                resource->res.data.extended_irq.polarity =
                    link->irq.polarity;
                if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
                        resource->res.data.extended_irq.shareable =
                            ACPI_EXCLUSIVE;
                else
                        resource->res.data.extended_irq.shareable = ACPI_SHARED;
                resource->res.data.extended_irq.interrupt_count = 1;
                resource->res.data.extended_irq.interrupts[0] = irq;
                /* ignore resource_source, it's optional */
                break;
        default:
                acpi_handle_err(handle, "Invalid resource type %d\n",
                                link->irq.resource_type);
                result = -EINVAL;
                goto end;

        }
        resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
        resource->end.length = sizeof(struct acpi_resource);

        /* Attempt to set the resource */
        status = acpi_set_current_resources(link->device->handle, &buffer);

        /* check for total failure */
        if (ACPI_FAILURE(status)) {
                acpi_evaluation_failure_warn(handle, "_SRS", status);
                result = -ENODEV;
                goto end;
        }

        /* Query _STA, set device->status */
        result = acpi_bus_get_status(link->device);
        if (result) {
                acpi_handle_err(handle, "Unable to read status\n");
                goto end;
        }
        if (!link->device->status.enabled)
                acpi_handle_warn(handle, "Disabled and referenced, BIOS bug\n");

        /* Query _CRS, set link->irq.active */
        result = acpi_pci_link_get_current(link);
        if (result) {
                goto end;
        }

        /*
         * Is current setting not what we set?
         * set link->irq.active
         */
        if (link->irq.active != irq) {
                /*
                 * policy: when _CRS doesn't return what we just _SRS
                 * assume _SRS worked and override _CRS value.
                 */
                acpi_handle_warn(handle, "BIOS reported IRQ %d, using IRQ %d\n",
                                 link->irq.active, irq);
                link->irq.active = irq;
        }

        acpi_handle_debug(handle, "Set IRQ %d\n", link->irq.active);

      end:
        kfree(resource);
        return result;
}

/* --------------------------------------------------------------------------
                            PCI Link IRQ Management
   -------------------------------------------------------------------------- */

/*
 * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 * Link Devices to move the PIRQs around to minimize sharing.
 *
 * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 * that the BIOS has already set to active.  This is necessary because
 * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 * even if acpi_irq_nobalance is set.
 *
 * A tables of penalties avoids directing PCI interrupts to well known
 * ISA IRQs. Boot params are available to over-ride the default table:
 *
 * List interrupts that are free for PCI use.
 * acpi_irq_pci=n[,m]
 *
 * List interrupts that should not be used for PCI:
 * acpi_irq_isa=n[,m]
 *
 * Note that PCI IRQ routers have a list of possible IRQs,
 * which may not include the IRQs this table says are available.
 *
 * Since this heuristic can't tell the difference between a link
 * that no device will attach to, vs. a link which may be shared
 * by multiple active devices -- it is not optimal.
 *
 * If interrupt performance is that important, get an IO-APIC system
 * with a pin dedicated to each device.  Or for that matter, an MSI
 * enabled system.
 */

#define ACPI_MAX_ISA_IRQS       16

#define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
#define PIRQ_PENALTY_PCI_USING          (16*16*16)
#define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
#define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
#define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)

static int acpi_isa_irq_penalty[ACPI_MAX_ISA_IRQS] = {
        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
        0,                              /* IRQ9  PCI, often acpi */
        0,                              /* IRQ10 PCI */
        0,                              /* IRQ11 PCI */
        PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
        PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
        PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
        PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
        /* >IRQ15 */
};

static int acpi_irq_pci_sharing_penalty(u32 irq)
{
        struct acpi_pci_link *link;
        int penalty = 0;
        int i;

        list_for_each_entry(link, &acpi_link_list, list) {
                /*
                 * If a link is active, penalize its IRQ heavily
                 * so we try to choose a different IRQ.
                 */
                if (link->irq.active && link->irq.active == irq)
                        penalty += PIRQ_PENALTY_PCI_USING;

                /*
                 * penalize the IRQs PCI might use, but not as severely.
                 */
                for (i = 0; i < link->irq.possible_count; i++)
                        if (link->irq.possible[i] == irq)
                                penalty += PIRQ_PENALTY_PCI_POSSIBLE /
                                        link->irq.possible_count;
        }

        return penalty;
}

static int acpi_irq_get_penalty(u32 irq)
{
        int penalty = 0;

        if (irq == sci_irq)
                penalty += sci_penalty;

        if (irq < ACPI_MAX_ISA_IRQS)
                return penalty + acpi_isa_irq_penalty[irq];

        return penalty + acpi_irq_pci_sharing_penalty(irq);
}

int __init acpi_irq_penalty_init(void)
{
        struct acpi_pci_link *link;
        int i;

        /*
         * Update penalties to facilitate IRQ balancing.
         */
        list_for_each_entry(link, &acpi_link_list, list) {

                /*
                 * reflect the possible and active irqs in the penalty table --
                 * useful for breaking ties.
                 */
                if (link->irq.possible_count) {
                        int penalty =
                            PIRQ_PENALTY_PCI_POSSIBLE /
                            link->irq.possible_count;

                        for (i = 0; i < link->irq.possible_count; i++) {
                                if (link->irq.possible[i] < ACPI_MAX_ISA_IRQS)
                                        acpi_isa_irq_penalty[link->irq.
                                                         possible[i]] +=
                                            penalty;
                        }

                } else if (link->irq.active &&
                                (link->irq.active < ACPI_MAX_ISA_IRQS)) {
                        acpi_isa_irq_penalty[link->irq.active] +=
                            PIRQ_PENALTY_PCI_POSSIBLE;
                }
        }

        return 0;
}

static int acpi_irq_balance = -1;       /* 0: static, 1: balance */

static int acpi_pci_link_allocate(struct acpi_pci_link *link)
{
        acpi_handle handle = link->device->handle;
        u32 irq;
        int i;

        if (link->irq.initialized) {
                if (link->refcnt == 0)
                        /* This means the link is disabled but initialized */
                        acpi_pci_link_set(link, link->irq.active);
                return 0;
        }

        /*
         * search for active IRQ in list of possible IRQs.
         */
        for (i = 0; i < link->irq.possible_count; ++i) {
                if (link->irq.active == link->irq.possible[i])
                        break;
        }
        /*
         * forget active IRQ that is not in possible list
         */
        if (i == link->irq.possible_count) {
                if (acpi_strict)
                        acpi_handle_warn(handle, "_CRS %d not found in _PRS\n",
                                         link->irq.active);
                link->irq.active = 0;
        }

        /*
         * if active found, use it; else pick entry from end of possible list.
         */
        if (link->irq.active)
                irq = link->irq.active;
        else
                irq = link->irq.possible[link->irq.possible_count - 1];

        if (acpi_irq_balance || !link->irq.active) {
                /*
                 * Select the best IRQ.  This is done in reverse to promote
                 * the use of IRQs 9, 10, 11, and >15.
                 */
                for (i = (link->irq.possible_count - 1); i >= 0; i--) {
                        if (acpi_irq_get_penalty(irq) >
                            acpi_irq_get_penalty(link->irq.possible[i]))
                                irq = link->irq.possible[i];
                }
        }
        if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
                acpi_handle_err(handle,
                                "No IRQ available. Try pci=noacpi or acpi=off\n");
                return -ENODEV;
        }

        /* Attempt to enable the link device at this IRQ. */
        if (acpi_pci_link_set(link, irq)) {
                acpi_handle_err(handle,
                                "Unable to set IRQ. Try pci=noacpi or acpi=off\n");
                return -ENODEV;
        } else {
                if (link->irq.active < ACPI_MAX_ISA_IRQS)
                        acpi_isa_irq_penalty[link->irq.active] +=
                                PIRQ_PENALTY_PCI_USING;

                acpi_handle_info(handle, "Enabled at IRQ %d\n",
                                 link->irq.active);
        }

        link->irq.initialized = 1;
        return 0;
}

/**
 * acpi_pci_link_allocate_irq(): Retrieve a link device GSI
 *
 * @handle: Handle for the link device
 * @index: GSI index
 * @triggering: pointer to store the GSI trigger
 * @polarity: pointer to store GSI polarity
 * @name: pointer to store link device name
 * @gsi: pointer to store GSI number
 *
 * Returns:
 *      0 on success with @triggering, @polarity, @name, @gsi initialized.
 *      -ENODEV on failure
 */
int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
                               int *polarity, char **name, u32 *gsi)
{
        struct acpi_device *device = acpi_fetch_acpi_dev(handle);
        struct acpi_pci_link *link;

        if (!device) {
                acpi_handle_err(handle, "Invalid link device\n");
                return -ENODEV;
        }

        link = acpi_driver_data(device);
        if (!link) {
                acpi_handle_err(handle, "Invalid link context\n");
                return -ENODEV;
        }

        /* TBD: Support multiple index (IRQ) entries per Link Device */
        if (index) {
                acpi_handle_err(handle, "Invalid index %d\n", index);
                return -ENODEV;
        }

        mutex_lock(&acpi_link_lock);
        if (acpi_pci_link_allocate(link)) {
                mutex_unlock(&acpi_link_lock);
                return -ENODEV;
        }

        if (!link->irq.active) {
                mutex_unlock(&acpi_link_lock);
                acpi_handle_err(handle, "Link active IRQ is 0!\n");
                return -ENODEV;
        }
        link->refcnt++;
        mutex_unlock(&acpi_link_lock);

        if (triggering)
                *triggering = link->irq.triggering;
        if (polarity)
                *polarity = link->irq.polarity;
        if (name)
                *name = acpi_device_bid(link->device);
        acpi_handle_debug(handle, "Link is referenced\n");
        *gsi = link->irq.active;

        return 0;
}

/*
 * We don't change link's irq information here.  After it is reenabled, we
 * continue use the info
 */
int acpi_pci_link_free_irq(acpi_handle handle)
{
        struct acpi_device *device = acpi_fetch_acpi_dev(handle);
        struct acpi_pci_link *link;

        if (!device) {
                acpi_handle_err(handle, "Invalid link device\n");
                return -1;
        }

        link = acpi_driver_data(device);
        if (!link) {
                acpi_handle_err(handle, "Invalid link context\n");
                return -1;
        }

        mutex_lock(&acpi_link_lock);
        if (!link->irq.initialized) {
                mutex_unlock(&acpi_link_lock);
                acpi_handle_err(handle, "Link isn't initialized\n");
                return -1;
        }
#ifdef  FUTURE_USE
        /*
         * The Link reference count allows us to _DISable an unused link
         * and suspend time, and set it again  on resume.
         * However, 2.6.12 still has irq_router.resume
         * which blindly restores the link state.
         * So we disable the reference count method
         * to prevent duplicate acpi_pci_link_set()
         * which would harm some systems
         */
        link->refcnt--;
#endif
        acpi_handle_debug(handle, "Link is dereferenced\n");

        if (link->refcnt == 0)
                acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);

        mutex_unlock(&acpi_link_lock);
        return link->irq.active;
}

/* --------------------------------------------------------------------------
                                 Driver Interface
   -------------------------------------------------------------------------- */

static int acpi_pci_link_add(struct acpi_device *device,
                             const struct acpi_device_id *not_used)
{
        acpi_handle handle = device->handle;
        struct acpi_pci_link *link;
        int result;
        int i;

        link = kzalloc_obj(struct acpi_pci_link);
        if (!link)
                return -ENOMEM;

        link->device = device;
        strscpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
        strscpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
        device->driver_data = link;

        mutex_lock(&acpi_link_lock);
        result = acpi_pci_link_get_possible(link);
        if (result)
                goto end;

        /* query and set link->irq.active */
        acpi_pci_link_get_current(link);

        pr_info("Interrupt link %s configured for IRQ %d\n",
                acpi_device_bid(device), link->irq.active);

        for (i = 0; i < link->irq.possible_count; i++) {
                if (link->irq.active != link->irq.possible[i])
                        acpi_handle_debug(handle, "Possible IRQ %d\n",
                                          link->irq.possible[i]);
        }

        if (!link->device->status.enabled)
                pr_info("Interrupt link %s disabled\n", acpi_device_bid(device));

        list_add_tail(&link->list, &acpi_link_list);

      end:
        /* disable all links -- to be activated on use */
        acpi_evaluate_object(handle, "_DIS", NULL, NULL);
        mutex_unlock(&acpi_link_lock);

        if (result)
                kfree(link);

        acpi_dev_clear_dependencies(device);

        return result < 0 ? result : 1;
}

static int acpi_pci_link_resume(struct acpi_pci_link *link)
{
        if (link->refcnt && link->irq.active && link->irq.initialized)
                return (acpi_pci_link_set(link, link->irq.active));

        return 0;
}

static void irqrouter_resume(void *data)
{
        struct acpi_pci_link *link;

        list_for_each_entry(link, &acpi_link_list, list) {
                acpi_pci_link_resume(link);
        }
}

static void acpi_pci_link_remove(struct acpi_device *device)
{
        struct acpi_pci_link *link;

        link = acpi_driver_data(device);

        mutex_lock(&acpi_link_lock);
        list_del(&link->list);
        mutex_unlock(&acpi_link_lock);

        kfree(link);
}

/*
 * modify acpi_isa_irq_penalty[] from cmdline
 */
static int __init acpi_irq_penalty_update(char *str, int used)
{
        int i;

        for (i = 0; i < 16; i++) {
                int retval;
                int irq;
                int new_penalty;

                retval = get_option(&str, &irq);

                if (!retval)
                        break;  /* no number found */

                /* see if this is a ISA IRQ */
                if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
                        continue;

                if (used)
                        new_penalty = acpi_isa_irq_penalty[irq] +
                                        PIRQ_PENALTY_ISA_USED;
                else
                        new_penalty = 0;

                acpi_isa_irq_penalty[irq] = new_penalty;
                if (retval != 2)        /* no next number */
                        break;
        }
        return 1;
}

/*
 * We'd like PNP to call this routine for the
 * single ISA_USED value for each legacy device.
 * But instead it calls us with each POSSIBLE setting.
 * There is no ISA_POSSIBLE weight, so we simply use
 * the (small) PCI_USING penalty.
 */
void acpi_penalize_isa_irq(int irq, int active)
{
        if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
                acpi_isa_irq_penalty[irq] +=
                  (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
}

bool acpi_isa_irq_available(int irq)
{
        return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
                    acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
}

void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
{
        sci_irq = irq;

        if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
            polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
                sci_penalty = PIRQ_PENALTY_PCI_USING;
        else
                sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
}

/*
 * Over-ride default table to reserve additional IRQs for use by ISA
 * e.g. acpi_irq_isa=5
 * Useful for telling ACPI how not to interfere with your ISA sound card.
 */
static int __init acpi_irq_isa(char *str)
{
        return acpi_irq_penalty_update(str, 1);
}

__setup("acpi_irq_isa=", acpi_irq_isa);

/*
 * Over-ride default table to free additional IRQs for use by PCI
 * e.g. acpi_irq_pci=7,15
 * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 */
static int __init acpi_irq_pci(char *str)
{
        return acpi_irq_penalty_update(str, 0);
}

__setup("acpi_irq_pci=", acpi_irq_pci);

static int __init acpi_irq_nobalance_set(char *str)
{
        acpi_irq_balance = 0;
        return 1;
}

__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);

static int __init acpi_irq_balance_set(char *str)
{
        acpi_irq_balance = 1;
        return 1;
}

__setup("acpi_irq_balance", acpi_irq_balance_set);

static const struct syscore_ops irqrouter_syscore_ops = {
        .resume = irqrouter_resume,
};

static struct syscore irqrouter_syscore = {
        .ops = &irqrouter_syscore_ops,
};

void __init acpi_pci_link_init(void)
{
        if (acpi_noirq)
                return;

        if (acpi_irq_balance == -1) {
                /* no command line switch: enable balancing in IOAPIC mode */
                if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
                        acpi_irq_balance = 1;
                else
                        acpi_irq_balance = 0;
        }
        register_syscore(&irqrouter_syscore);
        acpi_scan_add_handler(&pci_link_handler);
}