windfarm_pm112.c

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/*
 * Windfarm PowerMac thermal control.
 * Control loops for machines with SMU and PPC970MP processors.
 *
 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <[email protected]>
 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
 *
 * Use and redistribute under the terms of the GNU GPL v2.
 */
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <asm/prom.h>
#include <asm/smu.h>

#include "windfarm.h"
#include "windfarm_pid.h"

#define VERSION "0.2"

#define DEBUG
#undef LOTSA_DEBUG

#ifdef DEBUG
#define DBG(args...)    printk(args)
#else
#define DBG(args...)    do { } while(0)
#endif

#ifdef LOTSA_DEBUG
#define DBG_LOTS(args...)   printk(args)
#else
#define DBG_LOTS(args...)   do { } while(0)
#endif

/* define this to force CPU overtemp to 60 degree, useful for testing
 * the overtemp code
 */
#undef HACKED_OVERTEMP

/* We currently only handle 2 chips, 4 cores... */
#define NR_CHIPS    2
#define NR_CORES    4
#define NR_CPU_FANS 3 * NR_CHIPS

/* Controls and sensors */
static struct wf_sensor *sens_cpu_temp[NR_CORES];
static struct wf_sensor *sens_cpu_power[NR_CORES];
static struct wf_sensor *hd_temp;
static struct wf_sensor *slots_power;
static struct wf_sensor *u4_temp;

static struct wf_control *cpu_fans[NR_CPU_FANS];
static char *cpu_fan_names[NR_CPU_FANS] = {
    "cpu-rear-fan-0",
    "cpu-rear-fan-1",
    "cpu-front-fan-0",
    "cpu-front-fan-1",
    "cpu-pump-0",
    "cpu-pump-1",
};
static struct wf_control *cpufreq_clamp;

/* Second pump isn't required (and isn't actually present) */
#define CPU_FANS_REQD       (NR_CPU_FANS - 2)
#define FIRST_PUMP      4
#define LAST_PUMP       5

/* We keep a temperature history for average calculation of 180s */
#define CPU_TEMP_HIST_SIZE  180

/* Scale factor for fan speed, *100 */
static int cpu_fan_scale[NR_CPU_FANS] = {
    100,
    100,
    97,     /* inlet fans run at 97% of exhaust fan */
    97,
    100,        /* updated later */
    100,        /* updated later */
};

static struct wf_control *backside_fan;
static struct wf_control *slots_fan;
static struct wf_control *drive_bay_fan;

/* PID loop state */
static struct wf_cpu_pid_state cpu_pid[NR_CORES];
static u32 cpu_thist[CPU_TEMP_HIST_SIZE];
static int cpu_thist_pt;
static s64 cpu_thist_total;
static s32 cpu_all_tmax = 100 << 16;
static int cpu_last_target;
static struct wf_pid_state backside_pid;
static int backside_tick;
static struct wf_pid_state slots_pid;
static int slots_started;
static struct wf_pid_state drive_bay_pid;
static int drive_bay_tick;

static int nr_cores;
static int have_all_controls;
static int have_all_sensors;
static int started;

static int failure_state;
#define FAILURE_SENSOR      1
#define FAILURE_FAN     2
#define FAILURE_PERM        4
#define FAILURE_LOW_OVERTEMP    8
#define FAILURE_HIGH_OVERTEMP   16

/* Overtemp values */
#define LOW_OVER_AVERAGE    0
#define LOW_OVER_IMMEDIATE  (10 << 16)
#define LOW_OVER_CLEAR      ((-10) << 16)
#define HIGH_OVER_IMMEDIATE (14 << 16)
#define HIGH_OVER_AVERAGE   (10 << 16)
#define HIGH_OVER_IMMEDIATE (14 << 16)


/* Implementation... */
static int create_cpu_loop(int cpu)
{
    int chip = cpu / 2;
    int core = cpu & 1;
    struct smu_sdbp_header *hdr;
    struct smu_sdbp_cpupiddata *piddata;
    struct wf_cpu_pid_param pid;
    struct wf_control *main_fan = cpu_fans[0];
    s32 tmax;
    int fmin;

    /* Get PID params from the appropriate SAT */
    hdr = smu_sat_get_sdb_partition(chip, 0xC8 + core, NULL);
    if (hdr == NULL) {
        printk(KERN_WARNING"windfarm: can't get CPU PID fan config\n");
        return -EINVAL;
    }
    piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];

    /* Get FVT params to get Tmax; if not found, assume default */
    hdr = smu_sat_get_sdb_partition(chip, 0xC4 + core, NULL);
    if (hdr) {
        struct smu_sdbp_fvt *fvt = (struct smu_sdbp_fvt *)&hdr[1];
        tmax = fvt->maxtemp << 16;
    } else
        tmax = 95 << 16;    /* default to 95 degrees C */

    /* We keep a global tmax for overtemp calculations */
    if (tmax < cpu_all_tmax)
        cpu_all_tmax = tmax;

    /*
     * Darwin has a minimum fan speed of 1000 rpm for the 4-way and
     * 515 for the 2-way.  That appears to be overkill, so for now,
     * impose a minimum of 750 or 515.
     */
    fmin = (nr_cores > 2) ? 750 : 515;

    /* Initialize PID loop */
    pid.interval = 1;   /* seconds */
    pid.history_len = piddata->history_len;
    pid.gd = piddata->gd;
    pid.gp = piddata->gp;
    pid.gr = piddata->gr / piddata->history_len;
    pid.pmaxadj = (piddata->max_power << 16) - (piddata->power_adj << 8);
    pid.ttarget = tmax - (piddata->target_temp_delta << 16);
    pid.tmax = tmax;
    pid.min = main_fan->ops->get_min(main_fan);
    pid.max = main_fan->ops->get_max(main_fan);
    if (pid.min < fmin)
        pid.min = fmin;

    wf_cpu_pid_init(&cpu_pid[cpu], &pid);
    return 0;
}

static void cpu_max_all_fans(void)
{
    int i;

    /* We max all CPU fans in case of a sensor error. We also do the
     * cpufreq clamping now, even if it's supposedly done later by the
     * generic code anyway, we do it earlier here to react faster
     */
    if (cpufreq_clamp)
        wf_control_set_max(cpufreq_clamp);
    for (i = 0; i < NR_CPU_FANS; ++i)
        if (cpu_fans[i])
            wf_control_set_max(cpu_fans[i]);
}

static int cpu_check_overtemp(s32 temp)
{
    int new_state = 0;
    s32 t_avg, t_old;

    /* First check for immediate overtemps */
    if (temp >= (cpu_all_tmax + LOW_OVER_IMMEDIATE)) {
        new_state |= FAILURE_LOW_OVERTEMP;
        if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
            printk(KERN_ERR "windfarm: Overtemp due to immediate CPU"
                   " temperature !\n");
    }
    if (temp >= (cpu_all_tmax + HIGH_OVER_IMMEDIATE)) {
        new_state |= FAILURE_HIGH_OVERTEMP;
        if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
            printk(KERN_ERR "windfarm: Critical overtemp due to"
                   " immediate CPU temperature !\n");
    }

    /* We calculate a history of max temperatures and use that for the
     * overtemp management
     */
    t_old = cpu_thist[cpu_thist_pt];
    cpu_thist[cpu_thist_pt] = temp;
    cpu_thist_pt = (cpu_thist_pt + 1) % CPU_TEMP_HIST_SIZE;
    cpu_thist_total -= t_old;
    cpu_thist_total += temp;
    t_avg = cpu_thist_total / CPU_TEMP_HIST_SIZE;

    DBG_LOTS("t_avg = %d.%03d (out: %d.%03d, in: %d.%03d)\n",
         FIX32TOPRINT(t_avg), FIX32TOPRINT(t_old), FIX32TOPRINT(temp));

    /* Now check for average overtemps */
    if (t_avg >= (cpu_all_tmax + LOW_OVER_AVERAGE)) {
        new_state |= FAILURE_LOW_OVERTEMP;
        if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
            printk(KERN_ERR "windfarm: Overtemp due to average CPU"
                   " temperature !\n");
    }
    if (t_avg >= (cpu_all_tmax + HIGH_OVER_AVERAGE)) {
        new_state |= FAILURE_HIGH_OVERTEMP;
        if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
            printk(KERN_ERR "windfarm: Critical overtemp due to"
                   " average CPU temperature !\n");
    }

    /* Now handle overtemp conditions. We don't currently use the windfarm
     * overtemp handling core as it's not fully suited to the needs of those
     * new machine. This will be fixed later.
     */
    if (new_state) {
        /* High overtemp -> immediate shutdown */
        if (new_state & FAILURE_HIGH_OVERTEMP)
            machine_power_off();
        if ((failure_state & new_state) != new_state)
            cpu_max_all_fans();
        failure_state |= new_state;
    } else if ((failure_state & FAILURE_LOW_OVERTEMP) &&
           (temp < (cpu_all_tmax + LOW_OVER_CLEAR))) {
        printk(KERN_ERR "windfarm: Overtemp condition cleared !\n");
        failure_state &= ~FAILURE_LOW_OVERTEMP;
    }

    return failure_state & (FAILURE_LOW_OVERTEMP | FAILURE_HIGH_OVERTEMP);
}

static void cpu_fans_tick(void)
{
    int err, cpu;
    s32 greatest_delta = 0;
    s32 temp, power, t_max = 0;
    int i, t, target = 0;
    struct wf_sensor *sr;
    struct wf_control *ct;
    struct wf_cpu_pid_state *sp;

    DBG_LOTS(KERN_DEBUG);
    for (cpu = 0; cpu < nr_cores; ++cpu) {
        /* Get CPU core temperature */
        sr = sens_cpu_temp[cpu];
        err = sr->ops->get_value(sr, &temp);
        if (err) {
            DBG("\n");
            printk(KERN_WARNING "windfarm: CPU %d temperature "
                   "sensor error %d\n", cpu, err);
            failure_state |= FAILURE_SENSOR;
            cpu_max_all_fans();
            return;
        }

        /* Keep track of highest temp */
        t_max = max(t_max, temp);

        /* Get CPU power */
        sr = sens_cpu_power[cpu];
        err = sr->ops->get_value(sr, &power);
        if (err) {
            DBG("\n");
            printk(KERN_WARNING "windfarm: CPU %d power "
                   "sensor error %d\n", cpu, err);
            failure_state |= FAILURE_SENSOR;
            cpu_max_all_fans();
            return;
        }

        /* Run PID */
        sp = &cpu_pid[cpu];
        t = wf_cpu_pid_run(sp, power, temp);

        if (cpu == 0 || sp->last_delta > greatest_delta) {
            greatest_delta = sp->last_delta;
            target = t;
        }
        DBG_LOTS("[%d] P=%d.%.3d T=%d.%.3d ",
            cpu, FIX32TOPRINT(power), FIX32TOPRINT(temp));
    }
    DBG_LOTS("fans = %d, t_max = %d.%03d\n", target, FIX32TOPRINT(t_max));

    /* Darwin limits decrease to 20 per iteration */
    if (target < (cpu_last_target - 20))
        target = cpu_last_target - 20;
    cpu_last_target = target;
    for (cpu = 0; cpu < nr_cores; ++cpu)
        cpu_pid[cpu].target = target;

    /* Handle possible overtemps */
    if (cpu_check_overtemp(t_max))
        return;

    /* Set fans */
    for (i = 0; i < NR_CPU_FANS; ++i) {
        ct = cpu_fans[i];
        if (ct == NULL)
            continue;
        err = ct->ops->set_value(ct, target * cpu_fan_scale[i] / 100);
        if (err) {
            printk(KERN_WARNING "windfarm: fan %s reports "
                   "error %d\n", ct->name, err);
            failure_state |= FAILURE_FAN;
            break;
        }
    }
}

/* Backside/U4 fan */
static struct wf_pid_param backside_param = {
    .interval   = 5,
    .history_len    = 2,
    .gd     = 48 << 20,
    .gp     = 5 << 20,
    .gr     = 0,
    .itarget    = 64 << 16,
    .additive   = 1,
};

static void backside_fan_tick(void)
{
    s32 temp;
    int speed;
    int err;

    if (!backside_fan || !u4_temp)
        return;
    if (!backside_tick) {
        /* first time; initialize things */
        printk(KERN_INFO "windfarm: Backside control loop started.\n");
        backside_param.min = backside_fan->ops->get_min(backside_fan);
        backside_param.max = backside_fan->ops->get_max(backside_fan);
        wf_pid_init(&backside_pid, &backside_param);
        backside_tick = 1;
    }
    if (--backside_tick > 0)
        return;
    backside_tick = backside_pid.param.interval;

    err = u4_temp->ops->get_value(u4_temp, &temp);
    if (err) {
        printk(KERN_WARNING "windfarm: U4 temp sensor error %d\n",
               err);
        failure_state |= FAILURE_SENSOR;
        wf_control_set_max(backside_fan);
        return;
    }
    speed = wf_pid_run(&backside_pid, temp);
    DBG_LOTS("backside PID temp=%d.%.3d speed=%d\n",
         FIX32TOPRINT(temp), speed);

    err = backside_fan->ops->set_value(backside_fan, speed);
    if (err) {
        printk(KERN_WARNING "windfarm: backside fan error %d\n", err);
        failure_state |= FAILURE_FAN;
    }
}

/* Drive bay fan */
static struct wf_pid_param drive_bay_prm = {
    .interval   = 5,
    .history_len    = 2,
    .gd     = 30 << 20,
    .gp     = 5 << 20,
    .gr     = 0,
    .itarget    = 40 << 16,
    .additive   = 1,
};

static void drive_bay_fan_tick(void)
{
    s32 temp;
    int speed;
    int err;

    if (!drive_bay_fan || !hd_temp)
        return;
    if (!drive_bay_tick) {
        /* first time; initialize things */
        printk(KERN_INFO "windfarm: Drive bay control loop started.\n");
        drive_bay_prm.min = drive_bay_fan->ops->get_min(drive_bay_fan);
        drive_bay_prm.max = drive_bay_fan->ops->get_max(drive_bay_fan);
        wf_pid_init(&drive_bay_pid, &drive_bay_prm);
        drive_bay_tick = 1;
    }
    if (--drive_bay_tick > 0)
        return;
    drive_bay_tick = drive_bay_pid.param.interval;

    err = hd_temp->ops->get_value(hd_temp, &temp);
    if (err) {
        printk(KERN_WARNING "windfarm: drive bay temp sensor "
               "error %d\n", err);
        failure_state |= FAILURE_SENSOR;
        wf_control_set_max(drive_bay_fan);
        return;
    }
    speed = wf_pid_run(&drive_bay_pid, temp);
    DBG_LOTS("drive_bay PID temp=%d.%.3d speed=%d\n",
         FIX32TOPRINT(temp), speed);

    err = drive_bay_fan->ops->set_value(drive_bay_fan, speed);
    if (err) {
        printk(KERN_WARNING "windfarm: drive bay fan error %d\n", err);
        failure_state |= FAILURE_FAN;
    }
}

/* PCI slots area fan */
/* This makes the fan speed proportional to the power consumed */
static struct wf_pid_param slots_param = {
    .interval   = 1,
    .history_len    = 2,
    .gd     = 0,
    .gp     = 0,
    .gr     = 0x1277952,
    .itarget    = 0,
    .min        = 1560,
    .max        = 3510,
};

static void slots_fan_tick(void)
{
    s32 power;
    int speed;
    int err;

    if (!slots_fan || !slots_power)
        return;
    if (!slots_started) {
        /* first time; initialize things */
        printk(KERN_INFO "windfarm: Slots control loop started.\n");
        wf_pid_init(&slots_pid, &slots_param);
        slots_started = 1;
    }

    err = slots_power->ops->get_value(slots_power, &power);
    if (err) {
        printk(KERN_WARNING "windfarm: slots power sensor error %d\n",
               err);
        failure_state |= FAILURE_SENSOR;
        wf_control_set_max(slots_fan);
        return;
    }
    speed = wf_pid_run(&slots_pid, power);
    DBG_LOTS("slots PID power=%d.%.3d speed=%d\n",
         FIX32TOPRINT(power), speed);

    err = slots_fan->ops->set_value(slots_fan, speed);
    if (err) {
        printk(KERN_WARNING "windfarm: slots fan error %d\n", err);
        failure_state |= FAILURE_FAN;
    }
}

static void set_fail_state(void)
{
    int i;

    if (cpufreq_clamp)
        wf_control_set_max(cpufreq_clamp);
    for (i = 0; i < NR_CPU_FANS; ++i)
        if (cpu_fans[i])
            wf_control_set_max(cpu_fans[i]);
    if (backside_fan)
        wf_control_set_max(backside_fan);
    if (slots_fan)
        wf_control_set_max(slots_fan);
    if (drive_bay_fan)
        wf_control_set_max(drive_bay_fan);
}

static void pm112_tick(void)
{
    int i, last_failure;

    if (!started) {
        started = 1;
        printk(KERN_INFO "windfarm: CPUs control loops started.\n");
        for (i = 0; i < nr_cores; ++i) {
            if (create_cpu_loop(i) < 0) {
                failure_state = FAILURE_PERM;
                set_fail_state();
                break;
            }
        }
        DBG_LOTS("cpu_all_tmax=%d.%03d\n", FIX32TOPRINT(cpu_all_tmax));

#ifdef HACKED_OVERTEMP
        cpu_all_tmax = 60 << 16;
#endif
    }

    /* Permanent failure, bail out */
    if (failure_state & FAILURE_PERM)
        return;
    /* Clear all failure bits except low overtemp which will be eventually
     * cleared by the control loop itself
     */
    last_failure = failure_state;
    failure_state &= FAILURE_LOW_OVERTEMP;
    cpu_fans_tick();
    backside_fan_tick();
    slots_fan_tick();
    drive_bay_fan_tick();

    DBG_LOTS("last_failure: 0x%x, failure_state: %x\n",
         last_failure, failure_state);

    /* Check for failures. Any failure causes cpufreq clamping */
    if (failure_state && last_failure == 0 && cpufreq_clamp)
        wf_control_set_max(cpufreq_clamp);
    if (failure_state == 0 && last_failure && cpufreq_clamp)
        wf_control_set_min(cpufreq_clamp);

    /* That's it for now, we might want to deal with other failures
     * differently in the future though
     */
}

static void pm112_new_control(struct wf_control *ct)
{
    int i, max_exhaust;

    if (cpufreq_clamp == NULL && !strcmp(ct->name, "cpufreq-clamp")) {
        if (wf_get_control(ct) == 0)
            cpufreq_clamp = ct;
    }

    for (i = 0; i < NR_CPU_FANS; ++i) {
        if (!strcmp(ct->name, cpu_fan_names[i])) {
            if (cpu_fans[i] == NULL && wf_get_control(ct) == 0)
                cpu_fans[i] = ct;
            break;
        }
    }
    if (i >= NR_CPU_FANS) {
        /* not a CPU fan, try the others */
        if (!strcmp(ct->name, "backside-fan")) {
            if (backside_fan == NULL && wf_get_control(ct) == 0)
                backside_fan = ct;
        } else if (!strcmp(ct->name, "slots-fan")) {
            if (slots_fan == NULL && wf_get_control(ct) == 0)
                slots_fan = ct;
        } else if (!strcmp(ct->name, "drive-bay-fan")) {
            if (drive_bay_fan == NULL && wf_get_control(ct) == 0)
                drive_bay_fan = ct;
        }
        return;
    }

    for (i = 0; i < CPU_FANS_REQD; ++i)
        if (cpu_fans[i] == NULL)
            return;

    /* work out pump scaling factors */
    max_exhaust = cpu_fans[0]->ops->get_max(cpu_fans[0]);
    for (i = FIRST_PUMP; i <= LAST_PUMP; ++i)
        if ((ct = cpu_fans[i]) != NULL)
            cpu_fan_scale[i] =
                ct->ops->get_max(ct) * 100 / max_exhaust;

    have_all_controls = 1;
}

static void pm112_new_sensor(struct wf_sensor *sr)
{
    unsigned int i;

    if (!strncmp(sr->name, "cpu-temp-", 9)) {
        i = sr->name[9] - '0';
        if (sr->name[10] == 0 && i < NR_CORES &&
            sens_cpu_temp[i] == NULL && wf_get_sensor(sr) == 0)
            sens_cpu_temp[i] = sr;

    } else if (!strncmp(sr->name, "cpu-power-", 10)) {
        i = sr->name[10] - '0';
        if (sr->name[11] == 0 && i < NR_CORES &&
            sens_cpu_power[i] == NULL && wf_get_sensor(sr) == 0)
            sens_cpu_power[i] = sr;
    } else if (!strcmp(sr->name, "hd-temp")) {
        if (hd_temp == NULL && wf_get_sensor(sr) == 0)
            hd_temp = sr;
    } else if (!strcmp(sr->name, "slots-power")) {
        if (slots_power == NULL && wf_get_sensor(sr) == 0)
            slots_power = sr;
    } else if (!strcmp(sr->name, "backside-temp")) {
        if (u4_temp == NULL && wf_get_sensor(sr) == 0)
            u4_temp = sr;
    } else
        return;

    /* check if we have all the sensors we need */
    for (i = 0; i < nr_cores; ++i)
        if (sens_cpu_temp[i] == NULL || sens_cpu_power[i] == NULL)
            return;

    have_all_sensors = 1;
}

static int pm112_wf_notify(struct notifier_block *self,
               unsigned long event, void *data)
{
    switch (event) {
    case WF_EVENT_NEW_SENSOR:
        pm112_new_sensor(data);
        break;
    case WF_EVENT_NEW_CONTROL:
        pm112_new_control(data);
        break;
    case WF_EVENT_TICK:
        if (have_all_controls && have_all_sensors)
            pm112_tick();
    }
    return 0;
}

static struct notifier_block pm112_events = {
    .notifier_call = pm112_wf_notify,
};

static int wf_pm112_probe(struct platform_device *dev)
{
    wf_register_client(&pm112_events);
    return 0;
}

static int __devexit wf_pm112_remove(struct platform_device *dev)
{
    wf_unregister_client(&pm112_events);
    /* should release all sensors and controls */
    return 0;
}

static struct platform_driver wf_pm112_driver = {
    .probe = wf_pm112_probe,
    .remove = __devexit_p(wf_pm112_remove),
    .driver = {
        .name = "windfarm",
        .owner  = THIS_MODULE,
    },
};

static int __init wf_pm112_init(void)
{
    struct device_node *cpu;

    if (!of_machine_is_compatible("PowerMac11,2"))
        return -ENODEV;

    /* Count the number of CPU cores */
    nr_cores = 0;
    for (cpu = NULL; (cpu = of_find_node_by_type(cpu, "cpu")) != NULL; )
        ++nr_cores;

    printk(KERN_INFO "windfarm: initializing for dual-core desktop G5\n");

#ifdef MODULE
    request_module("windfarm_smu_controls");
    request_module("windfarm_smu_sensors");
    request_module("windfarm_smu_sat");
    request_module("windfarm_lm75_sensor");
    request_module("windfarm_max6690_sensor");
    request_module("windfarm_cpufreq_clamp");

#endif /* MODULE */

    platform_driver_register(&wf_pm112_driver);
    return 0;
}

static void __exit wf_pm112_exit(void)
{
    platform_driver_unregister(&wf_pm112_driver);
}

module_init(wf_pm112_init);
module_exit(wf_pm112_exit);

MODULE_AUTHOR("Paul Mackerras <[email protected]>");
MODULE_DESCRIPTION("Thermal control for PowerMac11,2");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:windfarm");