// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  fan_core.c - ACPI Fan core Driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2022 Intel Corporation. All rights reserved.
 */

#include <linux/bits.h>
#include <linux/kernel.h>
#include <linux/limits.h>
#include <linux/math.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/uuid.h>
#include <linux/thermal.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#include <linux/sort.h>

#include "fan.h"

#define ACPI_FAN_NOTIFY_STATE_CHANGED   0x80

/*
 * Defined inside the "Fan Noise Signal" section at
 * https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/design-guide.
 */
static const guid_t acpi_fan_microsoft_guid = GUID_INIT(0xA7611840, 0x99FE, 0x41AE, 0xA4, 0x88,
                                                        0x35, 0xC7, 0x59, 0x26, 0xC8, 0xEB);
#define ACPI_FAN_DSM_GET_TRIP_POINT_GRANULARITY 1
#define ACPI_FAN_DSM_SET_TRIP_POINTS            2
#define ACPI_FAN_DSM_GET_OPERATING_RANGES       3

/*
 * Ensures that fans with a very low trip point granularity
 * do not send too many notifications.
 */
static uint min_trip_distance = 100;
module_param(min_trip_distance, uint, 0);
MODULE_PARM_DESC(min_trip_distance, "Minimum distance between fan speed trip points in RPM");

static const struct acpi_device_id fan_device_ids[] = {
        ACPI_FAN_DEVICE_IDS,
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, fan_device_ids);

/* thermal cooling device callbacks */
static int fan_get_max_state(struct thermal_cooling_device *cdev, unsigned long
                             *state)
{
        struct acpi_device *device = cdev->devdata;
        struct acpi_fan *fan = acpi_driver_data(device);

        if (fan->acpi4) {
                if (fan->fif.fine_grain_ctrl)
                        *state = 100 / fan->fif.step_size;
                else
                        *state = fan->fps_count - 1;
        } else {
                *state = 1;
        }

        return 0;
}

int acpi_fan_get_fst(acpi_handle handle, struct acpi_fan_fst *fst)
{
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *obj;
        acpi_status status;
        int ret = 0;

        status = acpi_evaluate_object(handle, "_FST", NULL, &buffer);
        if (ACPI_FAILURE(status))
                return -EIO;

        obj = buffer.pointer;
        if (!obj)
                return -ENODATA;

        if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 3) {
                ret = -EPROTO;
                goto err;
        }

        if (obj->package.elements[0].type != ACPI_TYPE_INTEGER ||
            obj->package.elements[1].type != ACPI_TYPE_INTEGER ||
            obj->package.elements[2].type != ACPI_TYPE_INTEGER) {
                ret = -EPROTO;
                goto err;
        }

        fst->revision = obj->package.elements[0].integer.value;
        fst->control = obj->package.elements[1].integer.value;
        fst->speed = obj->package.elements[2].integer.value;

err:
        kfree(obj);
        return ret;
}

static int fan_get_state_acpi4(struct acpi_device *device, unsigned long *state)
{
        struct acpi_fan *fan = acpi_driver_data(device);
        struct acpi_fan_fst fst;
        int status, i;

        status = acpi_fan_get_fst(device->handle, &fst);
        if (status)
                return status;

        if (fan->fif.fine_grain_ctrl) {
                /* This control should be same what we set using _FSL by spec */
                if (fst.control > 100) {
                        dev_dbg(&device->dev, "Invalid control value returned\n");
                        goto match_fps;
                }

                *state = (int) fst.control / fan->fif.step_size;
                return 0;
        }

match_fps:
        for (i = 0; i < fan->fps_count; i++) {
                if (fst.control == fan->fps[i].control)
                        break;
        }
        if (i == fan->fps_count) {
                dev_dbg(&device->dev, "No matching fps control value\n");
                return -EINVAL;
        }

        *state = i;

        return status;
}

static int fan_get_state(struct acpi_device *device, unsigned long *state)
{
        int result;
        int acpi_state = ACPI_STATE_D0;

        result = acpi_device_update_power(device, &acpi_state);
        if (result)
                return result;

        *state = acpi_state == ACPI_STATE_D3_COLD
                        || acpi_state == ACPI_STATE_D3_HOT ?
                0 : (acpi_state == ACPI_STATE_D0 ? 1 : -1);
        return 0;
}

static int fan_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
                             *state)
{
        struct acpi_device *device = cdev->devdata;
        struct acpi_fan *fan = acpi_driver_data(device);

        if (fan->acpi4)
                return fan_get_state_acpi4(device, state);
        else
                return fan_get_state(device, state);
}

static int fan_set_state(struct acpi_device *device, unsigned long state)
{
        if (state != 0 && state != 1)
                return -EINVAL;

        return acpi_device_set_power(device,
                                     state ? ACPI_STATE_D0 : ACPI_STATE_D3_COLD);
}

static int fan_set_state_acpi4(struct acpi_device *device, unsigned long state)
{
        struct acpi_fan *fan = acpi_driver_data(device);
        acpi_status status;
        u64 value = state;
        int max_state;

        if (fan->fif.fine_grain_ctrl)
                max_state = 100 / fan->fif.step_size;
        else
                max_state = fan->fps_count - 1;

        if (state > max_state)
                return -EINVAL;

        if (fan->fif.fine_grain_ctrl) {
                value *= fan->fif.step_size;
                /* Spec allows compensate the last step only */
                if (value + fan->fif.step_size > 100)
                        value = 100;
        } else {
                value = fan->fps[state].control;
        }

        status = acpi_execute_simple_method(device->handle, "_FSL", value);
        if (ACPI_FAILURE(status)) {
                dev_dbg(&device->dev, "Failed to set state by _FSL\n");
                return -ENODEV;
        }

        return 0;
}

static int
fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
{
        struct acpi_device *device = cdev->devdata;
        struct acpi_fan *fan = acpi_driver_data(device);

        if (fan->acpi4)
                return fan_set_state_acpi4(device, state);
        else
                return fan_set_state(device, state);
}

static const struct thermal_cooling_device_ops fan_cooling_ops = {
        .get_max_state = fan_get_max_state,
        .get_cur_state = fan_get_cur_state,
        .set_cur_state = fan_set_cur_state,
};

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

static int acpi_fan_get_fif(struct acpi_device *device)
{
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        struct acpi_fan *fan = acpi_driver_data(device);
        struct acpi_buffer format = { sizeof("NNNN"), "NNNN" };
        u64 fields[4];
        struct acpi_buffer fif = { sizeof(fields), fields };
        union acpi_object *obj;
        acpi_status status;

        status = acpi_evaluate_object(device->handle, "_FIF", NULL, &buffer);
        if (ACPI_FAILURE(status))
                return status;

        obj = buffer.pointer;
        if (!obj || obj->type != ACPI_TYPE_PACKAGE) {
                dev_err(&device->dev, "Invalid _FIF data\n");
                status = -EINVAL;
                goto err;
        }

        status = acpi_extract_package(obj, &format, &fif);
        if (ACPI_FAILURE(status)) {
                dev_err(&device->dev, "Invalid _FIF element\n");
                status = -EINVAL;
                goto err;
        }

        fan->fif.revision = fields[0];
        fan->fif.fine_grain_ctrl = fields[1];
        fan->fif.step_size = fields[2];
        fan->fif.low_speed_notification = fields[3];

        /* If there is a bug in step size and set as 0, change to 1 */
        if (!fan->fif.step_size)
                fan->fif.step_size = 1;
        /* If step size > 9, change to 9 (by spec valid values 1-9) */
        else if (fan->fif.step_size > 9)
                fan->fif.step_size = 9;
err:
        kfree(obj);
        return status;
}

static int acpi_fan_speed_cmp(const void *a, const void *b)
{
        const struct acpi_fan_fps *fps1 = a;
        const struct acpi_fan_fps *fps2 = b;
        return fps1->speed - fps2->speed;
}

static int acpi_fan_get_fps(struct acpi_device *device)
{
        struct acpi_fan *fan = acpi_driver_data(device);
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *obj;
        acpi_status status;
        int i;

        status = acpi_evaluate_object(device->handle, "_FPS", NULL, &buffer);
        if (ACPI_FAILURE(status))
                return status;

        obj = buffer.pointer;
        if (!obj || obj->type != ACPI_TYPE_PACKAGE || obj->package.count < 2) {
                dev_err(&device->dev, "Invalid _FPS data\n");
                status = -EINVAL;
                goto err;
        }

        fan->fps_count = obj->package.count - 1; /* minus revision field */
        fan->fps = devm_kcalloc(&device->dev,
                                fan->fps_count, sizeof(struct acpi_fan_fps),
                                GFP_KERNEL);
        if (!fan->fps) {
                dev_err(&device->dev, "Not enough memory\n");
                status = -ENOMEM;
                goto err;
        }
        for (i = 0; i < fan->fps_count; i++) {
                struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
                struct acpi_buffer fps = { offsetof(struct acpi_fan_fps, name),
                                                &fan->fps[i] };
                status = acpi_extract_package(&obj->package.elements[i + 1],
                                              &format, &fps);
                if (ACPI_FAILURE(status)) {
                        dev_err(&device->dev, "Invalid _FPS element\n");
                        goto err;
                }
        }

        /* sort the state array according to fan speed in increase order */
        sort(fan->fps, fan->fps_count, sizeof(*fan->fps),
             acpi_fan_speed_cmp, NULL);

err:
        kfree(obj);
        return status;
}

static int acpi_fan_dsm_init(struct device *dev)
{
        union acpi_object dummy = {
                .package = {
                        .type = ACPI_TYPE_PACKAGE,
                        .count = 0,
                        .elements = NULL,
                },
        };
        struct acpi_fan *fan = dev_get_drvdata(dev);
        union acpi_object *obj;
        int ret = 0;

        if (!acpi_check_dsm(fan->handle, &acpi_fan_microsoft_guid, 0,
                            BIT(ACPI_FAN_DSM_GET_TRIP_POINT_GRANULARITY) |
                            BIT(ACPI_FAN_DSM_SET_TRIP_POINTS)))
                return 0;

        dev_info(dev, "Using Microsoft fan extensions\n");

        obj = acpi_evaluate_dsm_typed(fan->handle, &acpi_fan_microsoft_guid, 0,
                                      ACPI_FAN_DSM_GET_TRIP_POINT_GRANULARITY, &dummy,
                                      ACPI_TYPE_INTEGER);
        if (!obj)
                return -EIO;

        if (obj->integer.value > U32_MAX)
                ret = -EOVERFLOW;
        else
                fan->fan_trip_granularity = obj->integer.value;

        kfree(obj);

        return ret;
}

static int acpi_fan_dsm_set_trip_points(struct device *dev, u64 upper, u64 lower)
{
        union acpi_object args[2] = {
                {
                        .integer = {
                                .type = ACPI_TYPE_INTEGER,
                                .value = lower,
                        },
                },
                {
                        .integer = {
                                .type = ACPI_TYPE_INTEGER,
                                .value = upper,
                        },
                },
        };
        struct acpi_fan *fan = dev_get_drvdata(dev);
        union acpi_object in = {
                .package = {
                        .type = ACPI_TYPE_PACKAGE,
                        .count = ARRAY_SIZE(args),
                        .elements = args,
                },
        };
        union acpi_object *obj;

        obj = acpi_evaluate_dsm(fan->handle, &acpi_fan_microsoft_guid, 0,
                                ACPI_FAN_DSM_SET_TRIP_POINTS, &in);
        kfree(obj);

        return 0;
}

static int acpi_fan_dsm_start(struct device *dev)
{
        struct acpi_fan *fan = dev_get_drvdata(dev);
        int ret;

        if (!fan->fan_trip_granularity)
                return 0;

        /*
         * Some firmware implementations only update the values returned by the
         * _FST control method when a notification is received. This usually
         * works with Microsoft Windows as setting up trip points will keep
         * triggering said notifications, but will cause issues when using _FST
         * without the Microsoft-specific trip point extension.
         *
         * Because of this, an initial notification needs to be triggered to
         * start the cycle of trip points updates. This is achieved by setting
         * the trip points sequencially to two separate ranges. As by the
         * Microsoft specification the firmware should trigger a notification
         * immediately if the fan speed is outside the trip point range. This
         * _should_ result in at least one notification as both ranges do not
         * overlap, meaning that the current fan speed needs to be outside at
         * least one range.
         */
        ret = acpi_fan_dsm_set_trip_points(dev, fan->fan_trip_granularity, 0);
        if (ret < 0)
                return ret;

        return acpi_fan_dsm_set_trip_points(dev, fan->fan_trip_granularity * 3,
                                            fan->fan_trip_granularity * 2);
}

static int acpi_fan_dsm_update_trips_points(struct device *dev, struct acpi_fan_fst *fst)
{
        struct acpi_fan *fan = dev_get_drvdata(dev);
        u64 upper, lower;

        if (!fan->fan_trip_granularity)
                return 0;

        if (!acpi_fan_speed_valid(fst->speed))
                return -EINVAL;

        upper = roundup_u64(fst->speed + min_trip_distance, fan->fan_trip_granularity);
        if (fst->speed <= min_trip_distance) {
                lower = 0;
        } else {
                /*
                 * Valid fan speed values cannot be larger than 32 bit, so
                 * we can safely assume that no overflow will happen here.
                 */
                lower = rounddown((u32)fst->speed - min_trip_distance, fan->fan_trip_granularity);
        }

        return acpi_fan_dsm_set_trip_points(dev, upper, lower);
}

static void acpi_fan_notify_handler(acpi_handle handle, u32 event, void *context)
{
        struct device *dev = context;
        struct acpi_fan_fst fst;
        int ret;

        switch (event) {
        case ACPI_FAN_NOTIFY_STATE_CHANGED:
                /*
                 * The ACPI specification says that we must evaluate _FST when we
                 * receive an ACPI event indicating that the fan state has changed.
                 */
                ret = acpi_fan_get_fst(handle, &fst);
                if (ret < 0) {
                        dev_err(dev, "Error retrieving current fan status: %d\n", ret);
                } else {
                        ret = acpi_fan_dsm_update_trips_points(dev, &fst);
                        if (ret < 0)
                                dev_err(dev, "Failed to update trip points: %d\n", ret);
                }

                acpi_fan_notify_hwmon(dev);
                acpi_bus_generate_netlink_event("fan", dev_name(dev), event, 0);
                break;
        default:
                dev_dbg(dev, "Unsupported ACPI notification 0x%x\n", event);
                break;
        }
}

static void acpi_fan_notify_remove(void *data)
{
        struct acpi_fan *fan = data;

        acpi_remove_notify_handler(fan->handle, ACPI_DEVICE_NOTIFY, acpi_fan_notify_handler);
}

static int devm_acpi_fan_notify_init(struct device *dev)
{
        struct acpi_fan *fan = dev_get_drvdata(dev);
        acpi_status status;

        status = acpi_install_notify_handler(fan->handle, ACPI_DEVICE_NOTIFY,
                                             acpi_fan_notify_handler, dev);
        if (ACPI_FAILURE(status))
                return -EIO;

        return devm_add_action_or_reset(dev, acpi_fan_notify_remove, fan);
}

static int acpi_fan_probe(struct platform_device *pdev)
{
        int result = 0;
        struct thermal_cooling_device *cdev;
        struct acpi_fan *fan;
        struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
        char *name;

        if (!device)
                return -ENODEV;

        fan = devm_kzalloc(&pdev->dev, sizeof(*fan), GFP_KERNEL);
        if (!fan) {
                dev_err(&device->dev, "No memory for fan\n");
                return -ENOMEM;
        }

        fan->handle = device->handle;
        device->driver_data = fan;
        platform_set_drvdata(pdev, fan);

        if (acpi_has_method(device->handle, "_FST")) {
                fan->has_fst = true;
                fan->acpi4 = acpi_has_method(device->handle, "_FIF") &&
                                acpi_has_method(device->handle, "_FPS") &&
                                acpi_has_method(device->handle, "_FSL");
        }

        if (fan->acpi4) {
                result = acpi_fan_get_fif(device);
                if (result)
                        return result;

                result = acpi_fan_get_fps(device);
                if (result)
                        return result;
        }

        if (fan->has_fst) {
                result = acpi_fan_dsm_init(&pdev->dev);
                if (result)
                        return result;

                result = devm_acpi_fan_create_hwmon(&pdev->dev);
                if (result)
                        return result;

                result = devm_acpi_fan_notify_init(&pdev->dev);
                if (result)
                        return result;

                result = acpi_fan_dsm_start(&pdev->dev);
                if (result) {
                        dev_err(&pdev->dev, "Failed to start Microsoft fan extensions\n");
                        return result;
                }

                result = acpi_fan_create_attributes(device);
                if (result)
                        return result;
        }

        if (!fan->acpi4) {
                result = acpi_device_update_power(device, NULL);
                if (result) {
                        dev_err(&device->dev, "Failed to set initial power state\n");
                        goto err_end;
                }
        }

        if (!strncmp(pdev->name, "PNP0C0B", strlen("PNP0C0B")))
                name = "Fan";
        else
                name = acpi_device_bid(device);

        cdev = thermal_cooling_device_register(name, device,
                                                &fan_cooling_ops);
        if (IS_ERR(cdev)) {
                result = PTR_ERR(cdev);
                goto err_end;
        }

        dev_dbg(&pdev->dev, "registered as cooling_device%d\n", cdev->id);

        fan->cdev = cdev;
        result = sysfs_create_link(&pdev->dev.kobj,
                                   &cdev->device.kobj,
                                   "thermal_cooling");
        if (result) {
                dev_err(&pdev->dev, "Failed to create sysfs link 'thermal_cooling'\n");
                goto err_unregister;
        }

        result = sysfs_create_link(&cdev->device.kobj,
                                   &pdev->dev.kobj,
                                   "device");
        if (result) {
                dev_err(&pdev->dev, "Failed to create sysfs link 'device'\n");
                goto err_remove_link;
        }

        return 0;

err_remove_link:
        sysfs_remove_link(&pdev->dev.kobj, "thermal_cooling");
err_unregister:
        thermal_cooling_device_unregister(cdev);
err_end:
        if (fan->has_fst)
                acpi_fan_delete_attributes(device);

        return result;
}

static void acpi_fan_remove(struct platform_device *pdev)
{
        struct acpi_fan *fan = platform_get_drvdata(pdev);

        if (fan->has_fst) {
                struct acpi_device *device = ACPI_COMPANION(&pdev->dev);

                acpi_fan_delete_attributes(device);
        }
        sysfs_remove_link(&pdev->dev.kobj, "thermal_cooling");
        sysfs_remove_link(&fan->cdev->device.kobj, "device");
        thermal_cooling_device_unregister(fan->cdev);
}

#ifdef CONFIG_PM_SLEEP
static int acpi_fan_suspend(struct device *dev)
{
        struct acpi_fan *fan = dev_get_drvdata(dev);
        if (fan->acpi4)
                return 0;

        acpi_device_set_power(ACPI_COMPANION(dev), ACPI_STATE_D0);

        return AE_OK;
}

static int acpi_fan_resume(struct device *dev)
{
        struct acpi_fan *fan = dev_get_drvdata(dev);
        int result;

        if (fan->has_fst) {
                result = acpi_fan_dsm_start(dev);
                if (result)
                        dev_err(dev, "Failed to start Microsoft fan extensions: %d\n", result);
        }

        if (fan->acpi4)
                return 0;

        result = acpi_device_update_power(ACPI_COMPANION(dev), NULL);
        if (result)
                dev_err(dev, "Error updating fan power state\n");

        return result;
}

static const struct dev_pm_ops acpi_fan_pm = {
        .resume = acpi_fan_resume,
        .freeze = acpi_fan_suspend,
        .thaw = acpi_fan_resume,
        .restore = acpi_fan_resume,
};
#define FAN_PM_OPS_PTR (&acpi_fan_pm)

#else

#define FAN_PM_OPS_PTR NULL

#endif

static struct platform_driver acpi_fan_driver = {
        .probe = acpi_fan_probe,
        .remove = acpi_fan_remove,
        .driver = {
                .name = "acpi-fan",
                .acpi_match_table = fan_device_ids,
                .pm = FAN_PM_OPS_PTR,
        },
};

module_platform_driver(acpi_fan_driver);

MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Fan Driver");
MODULE_LICENSE("GPL");