/*
 * Thermal throttle event support code (such as syslog messaging and rate
 * limiting) that was factored out from x86_64 (mce_intel.c) and i386 (p4.c).
 *
 * This allows consistent reporting of CPU thermal throttle events.
 *
 * Maintains a counter in /sys that keeps track of the number of thermal
 * events, such that the user knows how bad the thermal problem might be
 * (since the logging to syslog and mcelog is rate limited).
 *
 * Author: Dmitriy Zavin (dmitriyz@google.com)
 *
 * Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c.
 *          Inspired by Ross Biro's and Al Borchers' counter code.
 */
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
#include <linux/export.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/cpu.h>

#include <asm/processor.h>
#include <asm/apic.h>
#include <asm/idle.h>
#include <asm/mce.h>
#include <asm/msr.h>

/* How long to wait between reporting thermal events */
#define CHECK_INTERVAL          (300 * HZ)

#define THERMAL_THROTTLING_EVENT        0
#define POWER_LIMIT_EVENT               1

/*
 * Current thermal event state:
 */
struct _thermal_state {
        bool                    new_event;
        int                     event;
        u64                     next_check;
        unsigned long           count;
        unsigned long           last_count;
};

struct thermal_state {
        struct _thermal_state core_throttle;
        struct _thermal_state core_power_limit;
        struct _thermal_state package_throttle;
        struct _thermal_state package_power_limit;
        struct _thermal_state core_thresh0;
        struct _thermal_state core_thresh1;
};

/* Callback to handle core threshold interrupts */
int (*platform_thermal_notify)(__u64 msr_val);
EXPORT_SYMBOL(platform_thermal_notify);

static DEFINE_PER_CPU(struct thermal_state, thermal_state);

static atomic_t therm_throt_en  = ATOMIC_INIT(0);

static u32 lvtthmr_init __read_mostly;

#ifdef CONFIG_SYSFS
#define define_therm_throt_device_one_ro(_name)                         \
        static DEVICE_ATTR(_name, 0444,                                 \
                           therm_throt_device_show_##_name,             \
                                   NULL)                                \

#define define_therm_throt_device_show_func(event, name)                \
                                                                        \
static ssize_t therm_throt_device_show_##event##_##name(                \
                        struct device *dev,                             \
                        struct device_attribute *attr,                  \
                        char *buf)                                      \
{                                                                       \
        unsigned int cpu = dev->id;                                     \
        ssize_t ret;                                                    \
                                                                        \
        preempt_disable();      /* CPU hotplug */                       \
        if (cpu_online(cpu)) {                                          \
                ret = sprintf(buf, "%lu\n",                             \
                              per_cpu(thermal_state, cpu).event.name);  \
        } else                                                          \
                ret = 0;                                                \
        preempt_enable();                                               \
                                                                        \
        return ret;                                                     \
}

define_therm_throt_device_show_func(core_throttle, count);
define_therm_throt_device_one_ro(core_throttle_count);

define_therm_throt_device_show_func(core_power_limit, count);
define_therm_throt_device_one_ro(core_power_limit_count);

define_therm_throt_device_show_func(package_throttle, count);
define_therm_throt_device_one_ro(package_throttle_count);

define_therm_throt_device_show_func(package_power_limit, count);
define_therm_throt_device_one_ro(package_power_limit_count);

static struct attribute *thermal_throttle_attrs[] = {
        &dev_attr_core_throttle_count.attr,
        NULL
};

static struct attribute_group thermal_attr_group = {
        .attrs  = thermal_throttle_attrs,
        .name   = "thermal_throttle"
};
#endif /* CONFIG_SYSFS */

#define CORE_LEVEL      0
#define PACKAGE_LEVEL   1

/***
 * therm_throt_process - Process thermal throttling event from interrupt
 * @curr: Whether the condition is current or not (boolean), since the
 *        thermal interrupt normally gets called both when the thermal
 *        event begins and once the event has ended.
 *
 * This function is called by the thermal interrupt after the
 * IRQ has been acknowledged.
 *
 * It will take care of rate limiting and printing messages to the syslog.
 *
 * Returns: 0 : Event should NOT be further logged, i.e. still in
 *              "timeout" from previous log message.
 *          1 : Event should be logged further, and a message has been
 *              printed to the syslog.
 */
static int therm_throt_process(bool new_event, int event, int level)
{
        struct _thermal_state *state;
        unsigned int this_cpu = smp_processor_id();
        bool old_event;
        u64 now;
        struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);

        now = get_jiffies_64();
        if (level == CORE_LEVEL) {
                if (event == THERMAL_THROTTLING_EVENT)
                        state = &pstate->core_throttle;
                else if (event == POWER_LIMIT_EVENT)
                        state = &pstate->core_power_limit;
                else
                         return 0;
        } else if (level == PACKAGE_LEVEL) {
                if (event == THERMAL_THROTTLING_EVENT)
                        state = &pstate->package_throttle;
                else if (event == POWER_LIMIT_EVENT)
                        state = &pstate->package_power_limit;
                else
                        return 0;
        } else
                return 0;

        old_event = state->new_event;
        state->new_event = new_event;

        if (new_event)
                state->count++;

        if (time_before64(now, state->next_check) &&
                        state->count != state->last_count)
                return 0;

        state->next_check = now + CHECK_INTERVAL;
        state->last_count = state->count;

        /* if we just entered the thermal event */
        if (new_event) {
                if (event == THERMAL_THROTTLING_EVENT)
                        printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
                                this_cpu,
                                level == CORE_LEVEL ? "Core" : "Package",
                                state->count);
                else
                        printk(KERN_CRIT "CPU%d: %s power limit notification (total events = %lu)\n",
                                this_cpu,
                                level == CORE_LEVEL ? "Core" : "Package",
                                state->count);
                return 1;
        }
        if (old_event) {
                if (event == THERMAL_THROTTLING_EVENT)
                        printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
                                this_cpu,
                                level == CORE_LEVEL ? "Core" : "Package");
                else
                        printk(KERN_INFO "CPU%d: %s power limit normal\n",
                                this_cpu,
                                level == CORE_LEVEL ? "Core" : "Package");
                return 1;
        }

        return 0;
}

static int thresh_event_valid(int event)
{
        struct _thermal_state *state;
        unsigned int this_cpu = smp_processor_id();
        struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
        u64 now = get_jiffies_64();

        state = (event == 0) ? &pstate->core_thresh0 : &pstate->core_thresh1;

        if (time_before64(now, state->next_check))
                return 0;

        state->next_check = now + CHECK_INTERVAL;
        return 1;
}

#ifdef CONFIG_SYSFS
/* Add/Remove thermal_throttle interface for CPU device: */
static __cpuinit int thermal_throttle_add_dev(struct device *dev,
                                unsigned int cpu)
{
        int err;
        struct cpuinfo_x86 *c = &cpu_data(cpu);

        err = sysfs_create_group(&dev->kobj, &thermal_attr_group);
        if (err)
                return err;

        if (cpu_has(c, X86_FEATURE_PLN))
                err = sysfs_add_file_to_group(&dev->kobj,
                                              &dev_attr_core_power_limit_count.attr,
                                              thermal_attr_group.name);
        if (cpu_has(c, X86_FEATURE_PTS)) {
                err = sysfs_add_file_to_group(&dev->kobj,
                                              &dev_attr_package_throttle_count.attr,
                                              thermal_attr_group.name);
                if (cpu_has(c, X86_FEATURE_PLN))
                        err = sysfs_add_file_to_group(&dev->kobj,
                                        &dev_attr_package_power_limit_count.attr,
                                        thermal_attr_group.name);
        }

        return err;
}

static __cpuinit void thermal_throttle_remove_dev(struct device *dev)
{
        sysfs_remove_group(&dev->kobj, &thermal_attr_group);
}

/* Mutex protecting device creation against CPU hotplug: */
static DEFINE_MUTEX(therm_cpu_lock);

/* Get notified when a cpu comes on/off. Be hotplug friendly. */
static __cpuinit int
thermal_throttle_cpu_callback(struct notifier_block *nfb,
                              unsigned long action,
                              void *hcpu)
{
        unsigned int cpu = (unsigned long)hcpu;
        struct device *dev;
        int err = 0;

        dev = get_cpu_device(cpu);

        switch (action) {
        case CPU_UP_PREPARE:
        case CPU_UP_PREPARE_FROZEN:
                mutex_lock(&therm_cpu_lock);
                err = thermal_throttle_add_dev(dev, cpu);
                mutex_unlock(&therm_cpu_lock);
                WARN_ON(err);
                break;
        case CPU_UP_CANCELED:
        case CPU_UP_CANCELED_FROZEN:
        case CPU_DEAD:
        case CPU_DEAD_FROZEN:
                mutex_lock(&therm_cpu_lock);
                thermal_throttle_remove_dev(dev);
                mutex_unlock(&therm_cpu_lock);
                break;
        }
        return notifier_from_errno(err);
}

static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
{
        .notifier_call = thermal_throttle_cpu_callback,
};

static __init int thermal_throttle_init_device(void)
{
        unsigned int cpu = 0;
        int err;

        if (!atomic_read(&therm_throt_en))
                return 0;

        register_hotcpu_notifier(&thermal_throttle_cpu_notifier);

#ifdef CONFIG_HOTPLUG_CPU
        mutex_lock(&therm_cpu_lock);
#endif
        /* connect live CPUs to sysfs */
        for_each_online_cpu(cpu) {
                err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
                WARN_ON(err);
        }
#ifdef CONFIG_HOTPLUG_CPU
        mutex_unlock(&therm_cpu_lock);
#endif

        return 0;
}
device_initcall(thermal_throttle_init_device);

#endif /* CONFIG_SYSFS */

static void notify_thresholds(__u64 msr_val)
{
        /* check whether the interrupt handler is defined;
         * otherwise simply return
         */
        if (!platform_thermal_notify)
                return;

        /* lower threshold reached */
        if ((msr_val & THERM_LOG_THRESHOLD0) && thresh_event_valid(0))
                platform_thermal_notify(msr_val);
        /* higher threshold reached */
        if ((msr_val & THERM_LOG_THRESHOLD1) && thresh_event_valid(1))
                platform_thermal_notify(msr_val);
}

/* Thermal transition interrupt handler */
static void intel_thermal_interrupt(void)
{
        __u64 msr_val;

        rdmsrl(MSR_IA32_THERM_STATUS, msr_val);

        /* Check for violation of core thermal thresholds*/
        notify_thresholds(msr_val);

        if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
                                THERMAL_THROTTLING_EVENT,
                                CORE_LEVEL) != 0)
                mce_log_therm_throt_event(msr_val);

        if (this_cpu_has(X86_FEATURE_PLN))
                therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
                                        POWER_LIMIT_EVENT,
                                        CORE_LEVEL);

        if (this_cpu_has(X86_FEATURE_PTS)) {
                rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
                therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
                                        THERMAL_THROTTLING_EVENT,
                                        PACKAGE_LEVEL);
                if (this_cpu_has(X86_FEATURE_PLN))
                        therm_throt_process(msr_val &
                                        PACKAGE_THERM_STATUS_POWER_LIMIT,
                                        POWER_LIMIT_EVENT,
                                        PACKAGE_LEVEL);
        }
}

static void unexpected_thermal_interrupt(void)
{
        printk(KERN_ERR "CPU%d: Unexpected LVT thermal interrupt!\n",
                        smp_processor_id());
}

static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;

asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
{
        irq_enter();
        exit_idle();
        inc_irq_stat(irq_thermal_count);
        smp_thermal_vector();
        irq_exit();
        /* Ack only at the end to avoid potential reentry */
        ack_APIC_irq();
}

/* Thermal monitoring depends on APIC, ACPI and clock modulation */
static int intel_thermal_supported(struct cpuinfo_x86 *c)
{
        if (!cpu_has_apic)
                return 0;
        if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
                return 0;
        return 1;
}

void __init mcheck_intel_therm_init(void)
{
        /*
         * This function is only called on boot CPU. Save the init thermal
         * LVT value on BSP and use that value to restore APs' thermal LVT
         * entry BIOS programmed later
         */
        if (intel_thermal_supported(&boot_cpu_data))
                lvtthmr_init = apic_read(APIC_LVTTHMR);
}

void intel_init_thermal(struct cpuinfo_x86 *c)
{
        unsigned int cpu = smp_processor_id();
        int tm2 = 0;
        u32 l, h;

        if (!intel_thermal_supported(c))
                return;

        /*
         * First check if its enabled already, in which case there might
         * be some SMM goo which handles it, so we can't even put a handler
         * since it might be delivered via SMI already:
         */
        rdmsr(MSR_IA32_MISC_ENABLE, l, h);

        h = lvtthmr_init;
        /*
         * The initial value of thermal LVT entries on all APs always reads
         * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
         * sequence to them and LVT registers are reset to 0s except for
         * the mask bits which are set to 1s when APs receive INIT IPI.
         * If BIOS takes over the thermal interrupt and sets its interrupt
         * delivery mode to SMI (not fixed), it restores the value that the
         * BIOS has programmed on AP based on BSP's info we saved since BIOS
         * is always setting the same value for all threads/cores.
         */
        if ((h & APIC_DM_FIXED_MASK) != APIC_DM_FIXED)
                apic_write(APIC_LVTTHMR, lvtthmr_init);


        if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
                printk(KERN_DEBUG
                       "CPU%d: Thermal monitoring handled by SMI\n", cpu);
                return;
        }

        /* Check whether a vector already exists */
        if (h & APIC_VECTOR_MASK) {
                printk(KERN_DEBUG
                       "CPU%d: Thermal LVT vector (%#x) already installed\n",
                       cpu, (h & APIC_VECTOR_MASK));
                return;
        }

        /* early Pentium M models use different method for enabling TM2 */
        if (cpu_has(c, X86_FEATURE_TM2)) {
                if (c->x86 == 6 && (c->x86_model == 9 || c->x86_model == 13)) {
                        rdmsr(MSR_THERM2_CTL, l, h);
                        if (l & MSR_THERM2_CTL_TM_SELECT)
                                tm2 = 1;
                } else if (l & MSR_IA32_MISC_ENABLE_TM2)
                        tm2 = 1;
        }

        /* We'll mask the thermal vector in the lapic till we're ready: */
        h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
        apic_write(APIC_LVTTHMR, h);

        rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
        if (cpu_has(c, X86_FEATURE_PLN))
                wrmsr(MSR_IA32_THERM_INTERRUPT,
                      l | (THERM_INT_LOW_ENABLE
                        | THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
        else
                wrmsr(MSR_IA32_THERM_INTERRUPT,
                      l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);

        if (cpu_has(c, X86_FEATURE_PTS)) {
                rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
                if (cpu_has(c, X86_FEATURE_PLN))
                        wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
                              l | (PACKAGE_THERM_INT_LOW_ENABLE
                                | PACKAGE_THERM_INT_HIGH_ENABLE
                                | PACKAGE_THERM_INT_PLN_ENABLE), h);
                else
                        wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
                              l | (PACKAGE_THERM_INT_LOW_ENABLE
                                | PACKAGE_THERM_INT_HIGH_ENABLE), h);
        }

        smp_thermal_vector = intel_thermal_interrupt;

        rdmsr(MSR_IA32_MISC_ENABLE, l, h);
        wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);

        /* Unmask the thermal vector: */
        l = apic_read(APIC_LVTTHMR);
        apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);

        printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
                       tm2 ? "TM2" : "TM1");

        /* enable thermal throttle processing */
        atomic_set(&therm_throt_en, 1);
}