// SPDX-License-Identifier: GPL-2.0-only
/*
 * Link physical devices with ACPI devices support
 *
 * Copyright (c) 2005 David Shaohua Li <shaohua.li@intel.com>
 * Copyright (c) 2005 Intel Corp.
 */

#define pr_fmt(fmt) "ACPI: " fmt

#include <linux/acpi_iort.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/acpi.h>
#include <linux/dma-mapping.h>
#include <linux/pci.h>
#include <linux/pci-acpi.h>
#include <linux/platform_device.h>

#include "internal.h"

static LIST_HEAD(bus_type_list);
static DECLARE_RWSEM(bus_type_sem);

#define PHYSICAL_NODE_STRING "physical_node"
#define PHYSICAL_NODE_NAME_SIZE (sizeof(PHYSICAL_NODE_STRING) + 10)

int register_acpi_bus_type(struct acpi_bus_type *type)
{
        if (acpi_disabled)
                return -ENODEV;
        if (type && type->match && type->find_companion) {
                down_write(&bus_type_sem);
                list_add_tail(&type->list, &bus_type_list);
                up_write(&bus_type_sem);
                pr_info("bus type %s registered\n", type->name);
                return 0;
        }
        return -ENODEV;
}
EXPORT_SYMBOL_GPL(register_acpi_bus_type);

int unregister_acpi_bus_type(struct acpi_bus_type *type)
{
        if (acpi_disabled)
                return 0;
        if (type) {
                down_write(&bus_type_sem);
                list_del_init(&type->list);
                up_write(&bus_type_sem);
                pr_info("bus type %s unregistered\n", type->name);
                return 0;
        }
        return -ENODEV;
}
EXPORT_SYMBOL_GPL(unregister_acpi_bus_type);

static struct acpi_bus_type *acpi_get_bus_type(struct device *dev)
{
        struct acpi_bus_type *tmp, *ret = NULL;

        down_read(&bus_type_sem);
        list_for_each_entry(tmp, &bus_type_list, list) {
                if (tmp->match(dev)) {
                        ret = tmp;
                        break;
                }
        }
        up_read(&bus_type_sem);
        return ret;
}

#define FIND_CHILD_MIN_SCORE    1
#define FIND_CHILD_MID_SCORE    2
#define FIND_CHILD_MAX_SCORE    3

static int match_any(struct acpi_device *adev, void *not_used)
{
        return 1;
}

static bool acpi_dev_has_children(struct acpi_device *adev)
{
        return acpi_dev_for_each_child(adev, match_any, NULL) > 0;
}

static int find_child_checks(struct acpi_device *adev, bool check_children)
{
        unsigned long long sta;
        acpi_status status;

        if (check_children && !acpi_dev_has_children(adev))
                return -ENODEV;

        status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
        if (status == AE_NOT_FOUND) {
                /*
                 * Special case: backlight device objects without _STA are
                 * preferred to other objects with the same _ADR value, because
                 * it is more likely that they are actually useful.
                 */
                if (adev->pnp.type.backlight)
                        return FIND_CHILD_MID_SCORE;

                return FIND_CHILD_MIN_SCORE;
        }

        if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED))
                return -ENODEV;

        /*
         * If the device has a _HID returning a valid ACPI/PNP device ID, it is
         * better to make it look less attractive here, so that the other device
         * with the same _ADR value (that may not have a valid device ID) can be
         * matched going forward.  [This means a second spec violation in a row,
         * so whatever we do here is best effort anyway.]
         */
        if (adev->pnp.type.platform_id)
                return FIND_CHILD_MIN_SCORE;

        return FIND_CHILD_MAX_SCORE;
}

struct find_child_walk_data {
        struct acpi_device *adev;
        u64 address;
        int score;
        bool check_sta;
        bool check_children;
};

static int check_one_child(struct acpi_device *adev, void *data)
{
        struct find_child_walk_data *wd = data;
        int score;

        if (!adev->pnp.type.bus_address || acpi_device_adr(adev) != wd->address)
                return 0;

        if (!wd->adev) {
                /*
                 * This is the first matching object, so save it.  If it is not
                 * necessary to look for any other matching objects, stop the
                 * search.
                 */
                wd->adev = adev;
                return !(wd->check_sta || wd->check_children);
        }

        /*
         * There is more than one matching device object with the same _ADR
         * value.  That really is unexpected, so we are kind of beyond the scope
         * of the spec here.  We have to choose which one to return, though.
         *
         * First, get the score for the previously found object and terminate
         * the walk if it is maximum.
        */
        if (!wd->score) {
                score = find_child_checks(wd->adev, wd->check_children);
                if (score == FIND_CHILD_MAX_SCORE)
                        return 1;

                wd->score = score;
        }
        /*
         * Second, if the object that has just been found has a better score,
         * replace the previously found one with it and terminate the walk if
         * the new score is maximum.
         */
        score = find_child_checks(adev, wd->check_children);
        if (score > wd->score) {
                wd->adev = adev;
                if (score == FIND_CHILD_MAX_SCORE)
                        return 1;

                wd->score = score;
        }

        /* Continue, because there may be better matches. */
        return 0;
}

static struct acpi_device *acpi_find_child(struct acpi_device *parent,
                                           u64 address, bool check_children,
                                           bool check_sta)
{
        struct find_child_walk_data wd = {
                .address = address,
                .check_children = check_children,
                .check_sta = check_sta,
                .adev = NULL,
                .score = 0,
        };

        if (parent)
                acpi_dev_for_each_child(parent, check_one_child, &wd);

        return wd.adev;
}

struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
                                           u64 address, bool check_children)
{
        return acpi_find_child(parent, address, check_children, true);
}
EXPORT_SYMBOL_GPL(acpi_find_child_device);

struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
                                           acpi_bus_address adr)
{
        return acpi_find_child(adev, adr, false, false);
}
EXPORT_SYMBOL_GPL(acpi_find_child_by_adr);

static void acpi_physnode_link_name(char *buf, unsigned int node_id)
{
        if (node_id > 0)
                snprintf(buf, PHYSICAL_NODE_NAME_SIZE,
                         PHYSICAL_NODE_STRING "%u", node_id);
        else
                strcpy(buf, PHYSICAL_NODE_STRING);
}

int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
{
        struct acpi_device_physical_node *physical_node, *pn;
        char physical_node_name[PHYSICAL_NODE_NAME_SIZE];
        struct list_head *physnode_list;
        unsigned int node_id;
        int retval = -EINVAL;

        if (has_acpi_companion(dev)) {
                if (acpi_dev) {
                        dev_warn(dev, "ACPI companion already set\n");
                        return -EINVAL;
                } else {
                        acpi_dev = ACPI_COMPANION(dev);
                }
        }
        if (!acpi_dev)
                return -EINVAL;

        acpi_dev_get(acpi_dev);
        get_device(dev);
        physical_node = kzalloc_obj(*physical_node);
        if (!physical_node) {
                retval = -ENOMEM;
                goto err;
        }

        mutex_lock(&acpi_dev->physical_node_lock);

        /*
         * Keep the list sorted by node_id so that the IDs of removed nodes can
         * be recycled easily.
         */
        physnode_list = &acpi_dev->physical_node_list;
        node_id = 0;
        list_for_each_entry(pn, &acpi_dev->physical_node_list, node) {
                /* Sanity check. */
                if (pn->dev == dev) {
                        mutex_unlock(&acpi_dev->physical_node_lock);

                        dev_warn(dev, "Already associated with ACPI node\n");
                        kfree(physical_node);
                        if (ACPI_COMPANION(dev) != acpi_dev)
                                goto err;

                        put_device(dev);
                        acpi_dev_put(acpi_dev);
                        return 0;
                }
                if (pn->node_id == node_id) {
                        physnode_list = &pn->node;
                        node_id++;
                }
        }

        physical_node->node_id = node_id;
        physical_node->dev = dev;
        list_add(&physical_node->node, physnode_list);
        acpi_dev->physical_node_count++;

        if (!has_acpi_companion(dev))
                ACPI_COMPANION_SET(dev, acpi_dev);

        acpi_physnode_link_name(physical_node_name, node_id);
        retval = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,
                                   physical_node_name);
        if (retval)
                dev_err(&acpi_dev->dev, "Failed to create link %s (%d)\n",
                        physical_node_name, retval);

        retval = sysfs_create_link(&dev->kobj, &acpi_dev->dev.kobj,
                                   "firmware_node");
        if (retval)
                dev_err(dev, "Failed to create link firmware_node (%d)\n",
                        retval);

        mutex_unlock(&acpi_dev->physical_node_lock);

        if (acpi_dev->wakeup.flags.valid)
                device_set_wakeup_capable(dev, true);

        return 0;

 err:
        ACPI_COMPANION_SET(dev, NULL);
        put_device(dev);
        acpi_dev_put(acpi_dev);
        return retval;
}
EXPORT_SYMBOL_GPL(acpi_bind_one);

int acpi_unbind_one(struct device *dev)
{
        struct acpi_device *acpi_dev = ACPI_COMPANION(dev);
        struct acpi_device_physical_node *entry;

        if (!acpi_dev)
                return 0;

        mutex_lock(&acpi_dev->physical_node_lock);

        list_for_each_entry(entry, &acpi_dev->physical_node_list, node)
                if (entry->dev == dev) {
                        char physnode_name[PHYSICAL_NODE_NAME_SIZE];

                        list_del(&entry->node);
                        acpi_dev->physical_node_count--;

                        acpi_physnode_link_name(physnode_name, entry->node_id);
                        sysfs_remove_link(&acpi_dev->dev.kobj, physnode_name);
                        sysfs_remove_link(&dev->kobj, "firmware_node");
                        ACPI_COMPANION_SET(dev, NULL);
                        /* Drop references taken by acpi_bind_one(). */
                        put_device(dev);
                        acpi_dev_put(acpi_dev);
                        kfree(entry);
                        break;
                }

        mutex_unlock(&acpi_dev->physical_node_lock);
        return 0;
}
EXPORT_SYMBOL_GPL(acpi_unbind_one);

void acpi_device_notify(struct device *dev)
{
        struct acpi_device *adev;
        int ret;

        ret = acpi_bind_one(dev, NULL);
        if (ret) {
                struct acpi_bus_type *type = acpi_get_bus_type(dev);

                if (!type)
                        goto err;

                adev = type->find_companion(dev);
                if (!adev) {
                        dev_dbg(dev, "ACPI companion not found\n");
                        goto err;
                }
                ret = acpi_bind_one(dev, adev);
                if (ret)
                        goto err;

                if (type->setup) {
                        type->setup(dev);
                        goto done;
                }
        } else {
                adev = ACPI_COMPANION(dev);

                if (dev_is_pci(dev)) {
                        pci_acpi_setup(dev, adev);
                        goto done;
                } else if (dev_is_platform(dev)) {
                        acpi_configure_pmsi_domain(dev);
                }
        }

        if (adev->handler && adev->handler->bind)
                adev->handler->bind(dev);

done:
        acpi_handle_debug(ACPI_HANDLE(dev), "Bound to device %s\n",
                          dev_name(dev));

        return;

err:
        dev_dbg(dev, "No ACPI support\n");
}

void acpi_device_notify_remove(struct device *dev)
{
        struct acpi_device *adev = ACPI_COMPANION(dev);

        if (!adev)
                return;

        if (dev_is_pci(dev))
                pci_acpi_cleanup(dev, adev);
        else if (adev->handler && adev->handler->unbind)
                adev->handler->unbind(dev);

        acpi_unbind_one(dev);
}