/*
 * intel_quark_dts_thermal.c
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * Contact Information:
 *  Ong Boon Leong <boon.leong.ong@intel.com>
 *  Intel Malaysia, Penang
 *
 * BSD LICENSE
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Quark DTS thermal driver is implemented by referencing
 * intel_soc_dts_thermal.c.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/thermal.h>
#include <asm/cpu_device_id.h>
#include <asm/iosf_mbi.h>

/* DTS reset is programmed via QRK_MBI_UNIT_SOC */
#define QRK_DTS_REG_OFFSET_RESET        0x34
#define QRK_DTS_RESET_BIT               BIT(0)

/* DTS enable is programmed via QRK_MBI_UNIT_RMU */
#define QRK_DTS_REG_OFFSET_ENABLE       0xB0
#define QRK_DTS_ENABLE_BIT              BIT(15)

/* Temperature Register is read via QRK_MBI_UNIT_RMU */
#define QRK_DTS_REG_OFFSET_TEMP         0xB1
#define QRK_DTS_MASK_TEMP               0xFF
#define QRK_DTS_OFFSET_TEMP             0
#define QRK_DTS_OFFSET_REL_TEMP         16
#define QRK_DTS_TEMP_BASE               50

/* Programmable Trip Point Register is configured via QRK_MBI_UNIT_RMU */
#define QRK_DTS_REG_OFFSET_PTPS         0xB2
#define QRK_DTS_MASK_TP_THRES           0xFF
#define QRK_DTS_SHIFT_TP                8
#define QRK_DTS_ID_TP_CRITICAL          0
#define QRK_DTS_ID_TP_HOT               1
#define QRK_DTS_SAFE_TP_THRES           105

/* Thermal Sensor Register Lock */
#define QRK_DTS_REG_OFFSET_LOCK         0x71
#define QRK_DTS_LOCK_BIT                BIT(5)

/* Quark DTS has 2 trip points: hot & catastrophic */
#define QRK_MAX_DTS_TRIPS       2

#define DEFAULT_POLL_DELAY      2000

struct soc_sensor_entry {
        bool locked;
        u32 store_ptps;
        u32 store_dts_enable;
        struct thermal_zone_device *tzone;
};

static struct soc_sensor_entry *soc_dts;

static int polling_delay = DEFAULT_POLL_DELAY;
module_param(polling_delay, int, 0644);
MODULE_PARM_DESC(polling_delay,
        "Polling interval for checking trip points (in milliseconds)");

static DEFINE_MUTEX(dts_update_mutex);

static int soc_dts_enable(struct thermal_zone_device *tzd)
{
        u32 out;
        struct soc_sensor_entry *aux_entry = thermal_zone_device_priv(tzd);
        int ret;

        ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                            QRK_DTS_REG_OFFSET_ENABLE, &out);
        if (ret)
                return ret;

        if (out & QRK_DTS_ENABLE_BIT)
                return 0;

        if (!aux_entry->locked) {
                out |= QRK_DTS_ENABLE_BIT;
                ret = iosf_mbi_write(QRK_MBI_UNIT_RMU, MBI_REG_WRITE,
                                     QRK_DTS_REG_OFFSET_ENABLE, out);
                if (ret)
                        return ret;
        } else {
                pr_info("DTS is locked. Cannot enable DTS\n");
                ret = -EPERM;
        }

        return ret;
}

static int soc_dts_disable(struct thermal_zone_device *tzd)
{
        u32 out;
        struct soc_sensor_entry *aux_entry = thermal_zone_device_priv(tzd);
        int ret;

        ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                            QRK_DTS_REG_OFFSET_ENABLE, &out);
        if (ret)
                return ret;

        if (!(out & QRK_DTS_ENABLE_BIT))
                return 0;

        if (!aux_entry->locked) {
                out &= ~QRK_DTS_ENABLE_BIT;
                ret = iosf_mbi_write(QRK_MBI_UNIT_RMU, MBI_REG_WRITE,
                                     QRK_DTS_REG_OFFSET_ENABLE, out);

                if (ret)
                        return ret;
        } else {
                pr_info("DTS is locked. Cannot disable DTS\n");
                ret = -EPERM;
        }

        return ret;
}

static int get_trip_temp(int trip)
{
        int status, temp;
        u32 out;

        mutex_lock(&dts_update_mutex);
        status = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                               QRK_DTS_REG_OFFSET_PTPS, &out);
        mutex_unlock(&dts_update_mutex);

        if (status)
                return THERMAL_TEMP_INVALID;

        /*
         * Thermal Sensor Programmable Trip Point Register has 8-bit
         * fields for critical (catastrophic) and hot set trip point
         * thresholds. The threshold value is always offset by its
         * temperature base (50 degree Celsius).
         */
        temp = (out >> (trip * QRK_DTS_SHIFT_TP)) & QRK_DTS_MASK_TP_THRES;
        temp -= QRK_DTS_TEMP_BASE;

        return temp;
}

static int update_trip_temp(struct soc_sensor_entry *aux_entry,
                                int trip_index, int temp)
{
        u32 out;
        u32 temp_out;
        u32 store_ptps;
        int ret;

        mutex_lock(&dts_update_mutex);
        if (aux_entry->locked) {
                ret = -EPERM;
                goto failed;
        }

        ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                            QRK_DTS_REG_OFFSET_PTPS, &store_ptps);
        if (ret)
                goto failed;

        /*
         * Protection against unsafe trip point thresdhold value.
         * As Quark X1000 data-sheet does not provide any recommendation
         * regarding the safe trip point threshold value to use, we choose
         * the safe value according to the threshold value set by UEFI BIOS.
         */
        if (temp > QRK_DTS_SAFE_TP_THRES)
                temp = QRK_DTS_SAFE_TP_THRES;

        /*
         * Thermal Sensor Programmable Trip Point Register has 8-bit
         * fields for critical (catastrophic) and hot set trip point
         * thresholds. The threshold value is always offset by its
         * temperature base (50 degree Celsius).
         */
        temp_out = temp + QRK_DTS_TEMP_BASE;
        out = (store_ptps & ~(QRK_DTS_MASK_TP_THRES <<
                (trip_index * QRK_DTS_SHIFT_TP)));
        out |= (temp_out & QRK_DTS_MASK_TP_THRES) <<
                (trip_index * QRK_DTS_SHIFT_TP);

        ret = iosf_mbi_write(QRK_MBI_UNIT_RMU, MBI_REG_WRITE,
                             QRK_DTS_REG_OFFSET_PTPS, out);

failed:
        mutex_unlock(&dts_update_mutex);
        return ret;
}

static inline int sys_set_trip_temp(struct thermal_zone_device *tzd,
                                    const struct thermal_trip *trip,
                                    int temp)
{
        unsigned int trip_index;

        switch (trip->type) {
        case THERMAL_TRIP_HOT:
                trip_index = QRK_DTS_ID_TP_HOT;
                break;

        case THERMAL_TRIP_CRITICAL:
                trip_index = QRK_DTS_ID_TP_CRITICAL;
                break;

        default:
                return -EINVAL;
        }

        return update_trip_temp(thermal_zone_device_priv(tzd), trip_index, temp);
}

static int sys_get_curr_temp(struct thermal_zone_device *tzd,
                                int *temp)
{
        u32 out;
        int ret;

        mutex_lock(&dts_update_mutex);
        ret = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                            QRK_DTS_REG_OFFSET_TEMP, &out);
        mutex_unlock(&dts_update_mutex);

        if (ret)
                return ret;

        /*
         * Thermal Sensor Temperature Register has 8-bit field
         * for temperature value (offset by temperature base
         * 50 degree Celsius).
         */
        out = (out >> QRK_DTS_OFFSET_TEMP) & QRK_DTS_MASK_TEMP;
        *temp = out - QRK_DTS_TEMP_BASE;

        return 0;
}

static int sys_change_mode(struct thermal_zone_device *tzd,
                           enum thermal_device_mode mode)
{
        int ret;

        mutex_lock(&dts_update_mutex);
        if (mode == THERMAL_DEVICE_ENABLED)
                ret = soc_dts_enable(tzd);
        else
                ret = soc_dts_disable(tzd);
        mutex_unlock(&dts_update_mutex);

        return ret;
}

static const struct thermal_zone_device_ops tzone_ops = {
        .get_temp = sys_get_curr_temp,
        .set_trip_temp = sys_set_trip_temp,
        .change_mode = sys_change_mode,
};

static void free_soc_dts(struct soc_sensor_entry *aux_entry)
{
        if (aux_entry) {
                if (!aux_entry->locked) {
                        mutex_lock(&dts_update_mutex);
                        iosf_mbi_write(QRK_MBI_UNIT_RMU, MBI_REG_WRITE,
                                       QRK_DTS_REG_OFFSET_ENABLE,
                                       aux_entry->store_dts_enable);

                        iosf_mbi_write(QRK_MBI_UNIT_RMU, MBI_REG_WRITE,
                                       QRK_DTS_REG_OFFSET_PTPS,
                                       aux_entry->store_ptps);
                        mutex_unlock(&dts_update_mutex);
                }
                thermal_zone_device_unregister(aux_entry->tzone);
                kfree(aux_entry);
        }
}

static struct soc_sensor_entry *alloc_soc_dts(void)
{
        struct thermal_trip trips[QRK_MAX_DTS_TRIPS] = { 0 };
        struct soc_sensor_entry *aux_entry;
        int err;
        u32 out;

        aux_entry = kzalloc_obj(*aux_entry);
        if (!aux_entry) {
                err = -ENOMEM;
                return ERR_PTR(-ENOMEM);
        }

        /* Check if DTS register is locked */
        err = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                            QRK_DTS_REG_OFFSET_LOCK, &out);
        if (err)
                goto err_ret;

        aux_entry->locked = !!(out & QRK_DTS_LOCK_BIT);

        /* Store DTS default state if DTS registers are not locked */
        if (!aux_entry->locked) {
                /* Store DTS default enable for restore on exit */
                err = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                                    QRK_DTS_REG_OFFSET_ENABLE,
                                    &aux_entry->store_dts_enable);
                if (err)
                        goto err_ret;

                /* Store DTS default PTPS register for restore on exit */
                err = iosf_mbi_read(QRK_MBI_UNIT_RMU, MBI_REG_READ,
                                    QRK_DTS_REG_OFFSET_PTPS,
                                    &aux_entry->store_ptps);
                if (err)
                        goto err_ret;

                trips[QRK_DTS_ID_TP_CRITICAL].flags |= THERMAL_TRIP_FLAG_RW_TEMP;
                trips[QRK_DTS_ID_TP_HOT].flags |= THERMAL_TRIP_FLAG_RW_TEMP;
        }

        trips[QRK_DTS_ID_TP_CRITICAL].temperature = get_trip_temp(QRK_DTS_ID_TP_CRITICAL);
        trips[QRK_DTS_ID_TP_CRITICAL].type = THERMAL_TRIP_CRITICAL;

        trips[QRK_DTS_ID_TP_HOT].temperature = get_trip_temp(QRK_DTS_ID_TP_HOT);
        trips[QRK_DTS_ID_TP_HOT].type = THERMAL_TRIP_HOT;

        aux_entry->tzone = thermal_zone_device_register_with_trips("quark_dts",
                                                                   trips,
                                                                   QRK_MAX_DTS_TRIPS,
                                                                   aux_entry,
                                                                   &tzone_ops,
                                                                   NULL, 0, polling_delay);
        if (IS_ERR(aux_entry->tzone)) {
                err = PTR_ERR(aux_entry->tzone);
                goto err_ret;
        }

        err = thermal_zone_device_enable(aux_entry->tzone);
        if (err)
                goto err_aux_status;

        return aux_entry;

err_aux_status:
        thermal_zone_device_unregister(aux_entry->tzone);
err_ret:
        kfree(aux_entry);
        return ERR_PTR(err);
}

static const struct x86_cpu_id qrk_thermal_ids[] __initconst  = {
        X86_MATCH_VFM(INTEL_QUARK_X1000, NULL),
        {}
};
MODULE_DEVICE_TABLE(x86cpu, qrk_thermal_ids);

static int __init intel_quark_thermal_init(void)
{
        if (!x86_match_cpu(qrk_thermal_ids) || !iosf_mbi_available())
                return -ENODEV;

        soc_dts = alloc_soc_dts();
        if (IS_ERR(soc_dts))
                return PTR_ERR(soc_dts);

        return 0;
}

static void __exit intel_quark_thermal_exit(void)
{
        free_soc_dts(soc_dts);
}

module_init(intel_quark_thermal_init)
module_exit(intel_quark_thermal_exit)

MODULE_DESCRIPTION("Intel Quark DTS Thermal Driver");
MODULE_AUTHOR("Ong Boon Leong <boon.leong.ong@intel.com>");
MODULE_LICENSE("Dual BSD/GPL");