/*
 * x86_pkg_temp_thermal driver
 * Copyright (c) 2013, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/param.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/thermal.h>
#include <linux/debugfs.h>
#include <asm/cpu_device_id.h>
#include <asm/mce.h>

/*
* Rate control delay: Idea is to introduce denounce effect
* This should be long enough to avoid reduce events, when
* threshold is set to a temperature, which is constantly
* violated, but at the short enough to take any action.
* The action can be remove threshold or change it to next
* interesting setting. Based on experiments, in around
* every 5 seconds under load will give us a significant
* temperature change.
*/
#define PKG_TEMP_THERMAL_NOTIFY_DELAY   5000
static int notify_delay_ms = PKG_TEMP_THERMAL_NOTIFY_DELAY;
module_param(notify_delay_ms, int, 0644);
MODULE_PARM_DESC(notify_delay_ms,
        "User space notification delay in milli seconds.");

/* Number of trip points in thermal zone. Currently it can't
* be more than 2. MSR can allow setting and getting notifications
* for only 2 thresholds. This define enforces this, if there
* is some wrong values returned by cpuid for number of thresholds.
*/
#define MAX_NUMBER_OF_TRIPS     2

struct pkg_device {
        int                             cpu;
        bool                            work_scheduled;
        u32                             tj_max;
        u32                             msr_pkg_therm_low;
        u32                             msr_pkg_therm_high;
        struct delayed_work             work;
        struct thermal_zone_device      *tzone;
        struct cpumask                  cpumask;
};

static struct thermal_zone_params pkg_temp_tz_params = {
        .no_hwmon       = true,
};

/* Keep track of how many package pointers we allocated in init() */
static int max_packages __read_mostly;
/* Array of package pointers */
static struct pkg_device **packages;
/* Serializes interrupt notification, work and hotplug */
static DEFINE_SPINLOCK(pkg_temp_lock);
/* Protects zone operation in the work function against hotplug removal */
static DEFINE_MUTEX(thermal_zone_mutex);

/* The dynamically assigned cpu hotplug state for module_exit() */
static enum cpuhp_state pkg_thermal_hp_state __read_mostly;

/* Debug counters to show using debugfs */
static struct dentry *debugfs;
static unsigned int pkg_interrupt_cnt;
static unsigned int pkg_work_cnt;

static int pkg_temp_debugfs_init(void)
{
        struct dentry *d;

        debugfs = debugfs_create_dir("pkg_temp_thermal", NULL);
        if (!debugfs)
                return -ENOENT;

        d = debugfs_create_u32("pkg_thres_interrupt", S_IRUGO, debugfs,
                               &pkg_interrupt_cnt);
        if (!d)
                goto err_out;

        d = debugfs_create_u32("pkg_thres_work", S_IRUGO, debugfs,
                               &pkg_work_cnt);
        if (!d)
                goto err_out;

        return 0;

err_out:
        debugfs_remove_recursive(debugfs);
        return -ENOENT;
}

/*
 * Protection:
 *
 * - cpu hotplug: Read serialized by cpu hotplug lock
 *                Write must hold pkg_temp_lock
 *
 * - Other callsites: Must hold pkg_temp_lock
 */
static struct pkg_device *pkg_temp_thermal_get_dev(unsigned int cpu)
{
        int pkgid = topology_logical_package_id(cpu);

        if (pkgid >= 0 && pkgid < max_packages)
                return packages[pkgid];
        return NULL;
}

/*
* tj-max is is interesting because threshold is set relative to this
* temperature.
*/
static int get_tj_max(int cpu, u32 *tj_max)
{
        u32 eax, edx, val;
        int err;

        err = rdmsr_safe_on_cpu(cpu, MSR_IA32_TEMPERATURE_TARGET, &eax, &edx);
        if (err)
                return err;

        val = (eax >> 16) & 0xff;
        *tj_max = val * 1000;

        return val ? 0 : -EINVAL;
}

static int sys_get_curr_temp(struct thermal_zone_device *tzd, int *temp)
{
        struct pkg_device *pkgdev = tzd->devdata;
        u32 eax, edx;

        rdmsr_on_cpu(pkgdev->cpu, MSR_IA32_PACKAGE_THERM_STATUS, &eax, &edx);
        if (eax & 0x80000000) {
                *temp = pkgdev->tj_max - ((eax >> 16) & 0x7f) * 1000;
                pr_debug("sys_get_curr_temp %d\n", *temp);
                return 0;
        }
        return -EINVAL;
}

static int sys_get_trip_temp(struct thermal_zone_device *tzd,
                             int trip, int *temp)
{
        struct pkg_device *pkgdev = tzd->devdata;
        unsigned long thres_reg_value;
        u32 mask, shift, eax, edx;
        int ret;

        if (trip >= MAX_NUMBER_OF_TRIPS)
                return -EINVAL;

        if (trip) {
                mask = THERM_MASK_THRESHOLD1;
                shift = THERM_SHIFT_THRESHOLD1;
        } else {
                mask = THERM_MASK_THRESHOLD0;
                shift = THERM_SHIFT_THRESHOLD0;
        }

        ret = rdmsr_on_cpu(pkgdev->cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT,
                           &eax, &edx);
        if (ret < 0)
                return ret;

        thres_reg_value = (eax & mask) >> shift;
        if (thres_reg_value)
                *temp = pkgdev->tj_max - thres_reg_value * 1000;
        else
                *temp = 0;
        pr_debug("sys_get_trip_temp %d\n", *temp);

        return 0;
}

static int
sys_set_trip_temp(struct thermal_zone_device *tzd, int trip, int temp)
{
        struct pkg_device *pkgdev = tzd->devdata;
        u32 l, h, mask, shift, intr;
        int ret;

        if (trip >= MAX_NUMBER_OF_TRIPS || temp >= pkgdev->tj_max)
                return -EINVAL;

        ret = rdmsr_on_cpu(pkgdev->cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT,
                           &l, &h);
        if (ret < 0)
                return ret;

        if (trip) {
                mask = THERM_MASK_THRESHOLD1;
                shift = THERM_SHIFT_THRESHOLD1;
                intr = THERM_INT_THRESHOLD1_ENABLE;
        } else {
                mask = THERM_MASK_THRESHOLD0;
                shift = THERM_SHIFT_THRESHOLD0;
                intr = THERM_INT_THRESHOLD0_ENABLE;
        }
        l &= ~mask;
        /*
        * When users space sets a trip temperature == 0, which is indication
        * that, it is no longer interested in receiving notifications.
        */
        if (!temp) {
                l &= ~intr;
        } else {
                l |= (pkgdev->tj_max - temp)/1000 << shift;
                l |= intr;
        }

        return wrmsr_on_cpu(pkgdev->cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
}

static int sys_get_trip_type(struct thermal_zone_device *thermal, int trip,
                             enum thermal_trip_type *type)
{
        *type = THERMAL_TRIP_PASSIVE;
        return 0;
}

/* Thermal zone callback registry */
static struct thermal_zone_device_ops tzone_ops = {
        .get_temp = sys_get_curr_temp,
        .get_trip_temp = sys_get_trip_temp,
        .get_trip_type = sys_get_trip_type,
        .set_trip_temp = sys_set_trip_temp,
};

static bool pkg_thermal_rate_control(void)
{
        return true;
}

/* Enable threshold interrupt on local package/cpu */
static inline void enable_pkg_thres_interrupt(void)
{
        u8 thres_0, thres_1;
        u32 l, h;

        rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
        /* only enable/disable if it had valid threshold value */
        thres_0 = (l & THERM_MASK_THRESHOLD0) >> THERM_SHIFT_THRESHOLD0;
        thres_1 = (l & THERM_MASK_THRESHOLD1) >> THERM_SHIFT_THRESHOLD1;
        if (thres_0)
                l |= THERM_INT_THRESHOLD0_ENABLE;
        if (thres_1)
                l |= THERM_INT_THRESHOLD1_ENABLE;
        wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
}

/* Disable threshold interrupt on local package/cpu */
static inline void disable_pkg_thres_interrupt(void)
{
        u32 l, h;

        rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);

        l &= ~(THERM_INT_THRESHOLD0_ENABLE | THERM_INT_THRESHOLD1_ENABLE);
        wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
}

static void pkg_temp_thermal_threshold_work_fn(struct work_struct *work)
{
        struct thermal_zone_device *tzone = NULL;
        int cpu = smp_processor_id();
        struct pkg_device *pkgdev;
        u64 msr_val, wr_val;

        mutex_lock(&thermal_zone_mutex);
        spin_lock_irq(&pkg_temp_lock);
        ++pkg_work_cnt;

        pkgdev = pkg_temp_thermal_get_dev(cpu);
        if (!pkgdev) {
                spin_unlock_irq(&pkg_temp_lock);
                mutex_unlock(&thermal_zone_mutex);
                return;
        }
        pkgdev->work_scheduled = false;

        rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
        wr_val = msr_val & ~(THERM_LOG_THRESHOLD0 | THERM_LOG_THRESHOLD1);
        if (wr_val != msr_val) {
                wrmsrl(MSR_IA32_PACKAGE_THERM_STATUS, wr_val);
                tzone = pkgdev->tzone;
        }

        enable_pkg_thres_interrupt();
        spin_unlock_irq(&pkg_temp_lock);

        /*
         * If tzone is not NULL, then thermal_zone_mutex will prevent the
         * concurrent removal in the cpu offline callback.
         */
        if (tzone)
                thermal_zone_device_update(tzone, THERMAL_EVENT_UNSPECIFIED);

        mutex_unlock(&thermal_zone_mutex);
}

static void pkg_thermal_schedule_work(int cpu, struct delayed_work *work)
{
        unsigned long ms = msecs_to_jiffies(notify_delay_ms);

        schedule_delayed_work_on(cpu, work, ms);
}

static int pkg_thermal_notify(u64 msr_val)
{
        int cpu = smp_processor_id();
        struct pkg_device *pkgdev;
        unsigned long flags;

        spin_lock_irqsave(&pkg_temp_lock, flags);
        ++pkg_interrupt_cnt;

        disable_pkg_thres_interrupt();

        /* Work is per package, so scheduling it once is enough. */
        pkgdev = pkg_temp_thermal_get_dev(cpu);
        if (pkgdev && !pkgdev->work_scheduled) {
                pkgdev->work_scheduled = true;
                pkg_thermal_schedule_work(pkgdev->cpu, &pkgdev->work);
        }

        spin_unlock_irqrestore(&pkg_temp_lock, flags);
        return 0;
}

static int pkg_temp_thermal_device_add(unsigned int cpu)
{
        int pkgid = topology_logical_package_id(cpu);
        u32 tj_max, eax, ebx, ecx, edx;
        struct pkg_device *pkgdev;
        int thres_count, err;

        if (pkgid >= max_packages)
                return -ENOMEM;

        cpuid(6, &eax, &ebx, &ecx, &edx);
        thres_count = ebx & 0x07;
        if (!thres_count)
                return -ENODEV;

        thres_count = clamp_val(thres_count, 0, MAX_NUMBER_OF_TRIPS);

        err = get_tj_max(cpu, &tj_max);
        if (err)
                return err;

        pkgdev = kzalloc(sizeof(*pkgdev), GFP_KERNEL);
        if (!pkgdev)
                return -ENOMEM;

        INIT_DELAYED_WORK(&pkgdev->work, pkg_temp_thermal_threshold_work_fn);
        pkgdev->cpu = cpu;
        pkgdev->tj_max = tj_max;
        pkgdev->tzone = thermal_zone_device_register("x86_pkg_temp",
                        thres_count,
                        (thres_count == MAX_NUMBER_OF_TRIPS) ? 0x03 : 0x01,
                        pkgdev, &tzone_ops, &pkg_temp_tz_params, 0, 0);
        if (IS_ERR(pkgdev->tzone)) {
                err = PTR_ERR(pkgdev->tzone);
                kfree(pkgdev);
                return err;
        }
        /* Store MSR value for package thermal interrupt, to restore at exit */
        rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, pkgdev->msr_pkg_therm_low,
              pkgdev->msr_pkg_therm_high);

        cpumask_set_cpu(cpu, &pkgdev->cpumask);
        spin_lock_irq(&pkg_temp_lock);
        packages[pkgid] = pkgdev;
        spin_unlock_irq(&pkg_temp_lock);
        return 0;
}

static int pkg_thermal_cpu_offline(unsigned int cpu)
{
        struct pkg_device *pkgdev = pkg_temp_thermal_get_dev(cpu);
        bool lastcpu, was_target;
        int target;

        if (!pkgdev)
                return 0;

        target = cpumask_any_but(&pkgdev->cpumask, cpu);
        cpumask_clear_cpu(cpu, &pkgdev->cpumask);
        lastcpu = target >= nr_cpu_ids;
        /*
         * Remove the sysfs files, if this is the last cpu in the package
         * before doing further cleanups.
         */
        if (lastcpu) {
                struct thermal_zone_device *tzone = pkgdev->tzone;

                /*
                 * We must protect against a work function calling
                 * thermal_zone_update, after/while unregister. We null out
                 * the pointer under the zone mutex, so the worker function
                 * won't try to call.
                 */
                mutex_lock(&thermal_zone_mutex);
                pkgdev->tzone = NULL;
                mutex_unlock(&thermal_zone_mutex);

                thermal_zone_device_unregister(tzone);
        }

        /* Protect against work and interrupts */
        spin_lock_irq(&pkg_temp_lock);

        /*
         * Check whether this cpu was the current target and store the new
         * one. When we drop the lock, then the interrupt notify function
         * will see the new target.
         */
        was_target = pkgdev->cpu == cpu;
        pkgdev->cpu = target;

        /*
         * If this is the last CPU in the package remove the package
         * reference from the array and restore the interrupt MSR. When we
         * drop the lock neither the interrupt notify function nor the
         * worker will see the package anymore.
         */
        if (lastcpu) {
                packages[topology_logical_package_id(cpu)] = NULL;
                /* After this point nothing touches the MSR anymore. */
                wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
                      pkgdev->msr_pkg_therm_low, pkgdev->msr_pkg_therm_high);
        }

        /*
         * Check whether there is work scheduled and whether the work is
         * targeted at the outgoing CPU.
         */
        if (pkgdev->work_scheduled && was_target) {
                /*
                 * To cancel the work we need to drop the lock, otherwise
                 * we might deadlock if the work needs to be flushed.
                 */
                spin_unlock_irq(&pkg_temp_lock);
                cancel_delayed_work_sync(&pkgdev->work);
                spin_lock_irq(&pkg_temp_lock);
                /*
                 * If this is not the last cpu in the package and the work
                 * did not run after we dropped the lock above, then we
                 * need to reschedule the work, otherwise the interrupt
                 * stays disabled forever.
                 */
                if (!lastcpu && pkgdev->work_scheduled)
                        pkg_thermal_schedule_work(target, &pkgdev->work);
        }

        spin_unlock_irq(&pkg_temp_lock);

        /* Final cleanup if this is the last cpu */
        if (lastcpu)
                kfree(pkgdev);
        return 0;
}

static int pkg_thermal_cpu_online(unsigned int cpu)
{
        struct pkg_device *pkgdev = pkg_temp_thermal_get_dev(cpu);
        struct cpuinfo_x86 *c = &cpu_data(cpu);

        /* Paranoia check */
        if (!cpu_has(c, X86_FEATURE_DTHERM) || !cpu_has(c, X86_FEATURE_PTS))
                return -ENODEV;

        /* If the package exists, nothing to do */
        if (pkgdev) {
                cpumask_set_cpu(cpu, &pkgdev->cpumask);
                return 0;
        }
        return pkg_temp_thermal_device_add(cpu);
}

static const struct x86_cpu_id __initconst pkg_temp_thermal_ids[] = {
        { X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_PTS },
        {}
};
MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids);

static int __init pkg_temp_thermal_init(void)
{
        int ret;

        if (!x86_match_cpu(pkg_temp_thermal_ids))
                return -ENODEV;

        max_packages = topology_max_packages();
        packages = kcalloc(max_packages, sizeof(struct pkg_device *),
                           GFP_KERNEL);
        if (!packages)
                return -ENOMEM;

        ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "thermal/x86_pkg:online",
                                pkg_thermal_cpu_online, pkg_thermal_cpu_offline);
        if (ret < 0)
                goto err;

        /* Store the state for module exit */
        pkg_thermal_hp_state = ret;

        platform_thermal_package_notify = pkg_thermal_notify;
        platform_thermal_package_rate_control = pkg_thermal_rate_control;

         /* Don't care if it fails */
        pkg_temp_debugfs_init();
        return 0;

err:
        kfree(packages);
        return ret;
}
module_init(pkg_temp_thermal_init)

static void __exit pkg_temp_thermal_exit(void)
{
        platform_thermal_package_notify = NULL;
        platform_thermal_package_rate_control = NULL;

        cpuhp_remove_state(pkg_thermal_hp_state);
        debugfs_remove_recursive(debugfs);
        kfree(packages);
}
module_exit(pkg_temp_thermal_exit)

MODULE_DESCRIPTION("X86 PKG TEMP Thermal Driver");
MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
MODULE_LICENSE("GPL v2");