bbc_envctrl.c

Go to the documentation of this file.

/* bbc_envctrl.c: UltraSPARC-III environment control driver.
 *
 * Copyright (C) 2001, 2008 David S. Miller ([email protected])
 */

#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/kmod.h>
#include <linux/reboot.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/of_device.h>
#include <asm/oplib.h>

#include "bbc_i2c.h"
#include "max1617.h"

#undef ENVCTRL_TRACE

/* WARNING: Making changes to this driver is very dangerous.
 *          If you misprogram the sensor chips they can
 *          cut the power on you instantly.
 */

/* Two temperature sensors exist in the SunBLADE-1000 enclosure.
 * Both are implemented using max1617 i2c devices.  Each max1617
 * monitors 2 temperatures, one for one of the cpu dies and the other
 * for the ambient temperature.
 *
 * The max1617 is capable of being programmed with power-off
 * temperature values, one low limit and one high limit.  These
 * can be controlled independently for the cpu or ambient temperature.
 * If a limit is violated, the power is simply shut off.  The frequency
 * with which the max1617 does temperature sampling can be controlled
 * as well.
 *
 * Three fans exist inside the machine, all three are controlled with
 * an i2c digital to analog converter.  There is a fan directed at the
 * two processor slots, another for the rest of the enclosure, and the
 * third is for the power supply.  The first two fans may be speed
 * controlled by changing the voltage fed to them.  The third fan may
 * only be completely off or on.  The third fan is meant to only be
 * disabled/enabled when entering/exiting the lowest power-saving
 * mode of the machine.
 *
 * An environmental control kernel thread periodically monitors all
 * temperature sensors.  Based upon the samples it will adjust the
 * fan speeds to try and keep the system within a certain temperature
 * range (the goal being to make the fans as quiet as possible without
 * allowing the system to get too hot).
 *
 * If the temperature begins to rise/fall outside of the acceptable
 * operating range, a periodic warning will be sent to the kernel log.
 * The fans will be put on full blast to attempt to deal with this
 * situation.  After exceeding the acceptable operating range by a
 * certain threshold, the kernel thread will shut down the system.
 * Here, the thread is attempting to shut the machine down cleanly
 * before the hardware based power-off event is triggered.
 */

/* These settings are in Celsius.  We use these defaults only
 * if we cannot interrogate the cpu-fru SEEPROM.
 */
struct temp_limits {
    s8 high_pwroff, high_shutdown, high_warn;
    s8 low_warn, low_shutdown, low_pwroff;
};

static struct temp_limits cpu_temp_limits[2] = {
    { 100, 85, 80, 5, -5, -10 },
    { 100, 85, 80, 5, -5, -10 },
};

static struct temp_limits amb_temp_limits[2] = {
    { 65, 55, 40, 5, -5, -10 },
    { 65, 55, 40, 5, -5, -10 },
};

static LIST_HEAD(all_temps);
static LIST_HEAD(all_fans);

#define CPU_FAN_REG 0xf0
#define SYS_FAN_REG 0xf2
#define PSUPPLY_FAN_REG 0xf4

#define FAN_SPEED_MIN   0x0c
#define FAN_SPEED_MAX   0x3f

#define PSUPPLY_FAN_ON  0x1f
#define PSUPPLY_FAN_OFF 0x00

static void set_fan_speeds(struct bbc_fan_control *fp)
{
    /* Put temperatures into range so we don't mis-program
     * the hardware.
     */
    if (fp->cpu_fan_speed < FAN_SPEED_MIN)
        fp->cpu_fan_speed = FAN_SPEED_MIN;
    if (fp->cpu_fan_speed > FAN_SPEED_MAX)
        fp->cpu_fan_speed = FAN_SPEED_MAX;
    if (fp->system_fan_speed < FAN_SPEED_MIN)
        fp->system_fan_speed = FAN_SPEED_MIN;
    if (fp->system_fan_speed > FAN_SPEED_MAX)
        fp->system_fan_speed = FAN_SPEED_MAX;
#ifdef ENVCTRL_TRACE
    printk("fan%d: Changed fan speed to cpu(%02x) sys(%02x)\n",
           fp->index,
           fp->cpu_fan_speed, fp->system_fan_speed);
#endif

    bbc_i2c_writeb(fp->client, fp->cpu_fan_speed, CPU_FAN_REG);
    bbc_i2c_writeb(fp->client, fp->system_fan_speed, SYS_FAN_REG);
    bbc_i2c_writeb(fp->client,
               (fp->psupply_fan_on ?
            PSUPPLY_FAN_ON : PSUPPLY_FAN_OFF),
               PSUPPLY_FAN_REG);
}

static void get_current_temps(struct bbc_cpu_temperature *tp)
{
    tp->prev_amb_temp = tp->curr_amb_temp;
    bbc_i2c_readb(tp->client,
              (unsigned char *) &tp->curr_amb_temp,
              MAX1617_AMB_TEMP);
    tp->prev_cpu_temp = tp->curr_cpu_temp;
    bbc_i2c_readb(tp->client,
              (unsigned char *) &tp->curr_cpu_temp,
              MAX1617_CPU_TEMP);
#ifdef ENVCTRL_TRACE
    printk("temp%d: cpu(%d C) amb(%d C)\n",
           tp->index,
           (int) tp->curr_cpu_temp, (int) tp->curr_amb_temp);
#endif
}


static void do_envctrl_shutdown(struct bbc_cpu_temperature *tp)
{
    static int shutting_down = 0;
    char *type = "???";
    s8 val = -1;

    if (shutting_down != 0)
        return;

    if (tp->curr_amb_temp >= amb_temp_limits[tp->index].high_shutdown ||
        tp->curr_amb_temp < amb_temp_limits[tp->index].low_shutdown) {
        type = "ambient";
        val = tp->curr_amb_temp;
    } else if (tp->curr_cpu_temp >= cpu_temp_limits[tp->index].high_shutdown ||
           tp->curr_cpu_temp < cpu_temp_limits[tp->index].low_shutdown) {
        type = "CPU";
        val = tp->curr_cpu_temp;
    }

    printk(KERN_CRIT "temp%d: Outside of safe %s "
           "operating temperature, %d C.\n",
           tp->index, type, val);

    printk(KERN_CRIT "kenvctrld: Shutting down the system now.\n");

    shutting_down = 1;
    if (orderly_poweroff(true) < 0)
        printk(KERN_CRIT "envctrl: shutdown execution failed\n");
}

#define WARN_INTERVAL   (30 * HZ)

static void analyze_ambient_temp(struct bbc_cpu_temperature *tp, unsigned long *last_warn, int tick)
{
    int ret = 0;

    if (time_after(jiffies, (*last_warn + WARN_INTERVAL))) {
        if (tp->curr_amb_temp >=
            amb_temp_limits[tp->index].high_warn) {
            printk(KERN_WARNING "temp%d: "
                   "Above safe ambient operating temperature, %d C.\n",
                   tp->index, (int) tp->curr_amb_temp);
            ret = 1;
        } else if (tp->curr_amb_temp <
               amb_temp_limits[tp->index].low_warn) {
            printk(KERN_WARNING "temp%d: "
                   "Below safe ambient operating temperature, %d C.\n",
                   tp->index, (int) tp->curr_amb_temp);
            ret = 1;
        }
        if (ret)
            *last_warn = jiffies;
    } else if (tp->curr_amb_temp >= amb_temp_limits[tp->index].high_warn ||
           tp->curr_amb_temp < amb_temp_limits[tp->index].low_warn)
        ret = 1;

    /* Now check the shutdown limits. */
    if (tp->curr_amb_temp >= amb_temp_limits[tp->index].high_shutdown ||
        tp->curr_amb_temp < amb_temp_limits[tp->index].low_shutdown) {
        do_envctrl_shutdown(tp);
        ret = 1;
    }

    if (ret) {
        tp->fan_todo[FAN_AMBIENT] = FAN_FULLBLAST;
    } else if ((tick & (8 - 1)) == 0) {
        s8 amb_goal_hi = amb_temp_limits[tp->index].high_warn - 10;
        s8 amb_goal_lo;

        amb_goal_lo = amb_goal_hi - 3;

        /* We do not try to avoid 'too cold' events.  Basically we
         * only try to deal with over-heating and fan noise reduction.
         */
        if (tp->avg_amb_temp < amb_goal_hi) {
            if (tp->avg_amb_temp >= amb_goal_lo)
                tp->fan_todo[FAN_AMBIENT] = FAN_SAME;
            else
                tp->fan_todo[FAN_AMBIENT] = FAN_SLOWER;
        } else {
            tp->fan_todo[FAN_AMBIENT] = FAN_FASTER;
        }
    } else {
        tp->fan_todo[FAN_AMBIENT] = FAN_SAME;
    }
}

static void analyze_cpu_temp(struct bbc_cpu_temperature *tp, unsigned long *last_warn, int tick)
{
    int ret = 0;

    if (time_after(jiffies, (*last_warn + WARN_INTERVAL))) {
        if (tp->curr_cpu_temp >=
            cpu_temp_limits[tp->index].high_warn) {
            printk(KERN_WARNING "temp%d: "
                   "Above safe CPU operating temperature, %d C.\n",
                   tp->index, (int) tp->curr_cpu_temp);
            ret = 1;
        } else if (tp->curr_cpu_temp <
               cpu_temp_limits[tp->index].low_warn) {
            printk(KERN_WARNING "temp%d: "
                   "Below safe CPU operating temperature, %d C.\n",
                   tp->index, (int) tp->curr_cpu_temp);
            ret = 1;
        }
        if (ret)
            *last_warn = jiffies;
    } else if (tp->curr_cpu_temp >= cpu_temp_limits[tp->index].high_warn ||
           tp->curr_cpu_temp < cpu_temp_limits[tp->index].low_warn)
        ret = 1;

    /* Now check the shutdown limits. */
    if (tp->curr_cpu_temp >= cpu_temp_limits[tp->index].high_shutdown ||
        tp->curr_cpu_temp < cpu_temp_limits[tp->index].low_shutdown) {
        do_envctrl_shutdown(tp);
        ret = 1;
    }

    if (ret) {
        tp->fan_todo[FAN_CPU] = FAN_FULLBLAST;
    } else if ((tick & (8 - 1)) == 0) {
        s8 cpu_goal_hi = cpu_temp_limits[tp->index].high_warn - 10;
        s8 cpu_goal_lo;

        cpu_goal_lo = cpu_goal_hi - 3;

        /* We do not try to avoid 'too cold' events.  Basically we
         * only try to deal with over-heating and fan noise reduction.
         */
        if (tp->avg_cpu_temp < cpu_goal_hi) {
            if (tp->avg_cpu_temp >= cpu_goal_lo)
                tp->fan_todo[FAN_CPU] = FAN_SAME;
            else
                tp->fan_todo[FAN_CPU] = FAN_SLOWER;
        } else {
            tp->fan_todo[FAN_CPU] = FAN_FASTER;
        }
    } else {
        tp->fan_todo[FAN_CPU] = FAN_SAME;
    }
}

static void analyze_temps(struct bbc_cpu_temperature *tp, unsigned long *last_warn)
{
    tp->avg_amb_temp = (s8)((int)((int)tp->avg_amb_temp + (int)tp->curr_amb_temp) / 2);
    tp->avg_cpu_temp = (s8)((int)((int)tp->avg_cpu_temp + (int)tp->curr_cpu_temp) / 2);

    analyze_ambient_temp(tp, last_warn, tp->sample_tick);
    analyze_cpu_temp(tp, last_warn, tp->sample_tick);

    tp->sample_tick++;
}

static enum fan_action prioritize_fan_action(int which_fan)
{
    struct bbc_cpu_temperature *tp;
    enum fan_action decision = FAN_STATE_MAX;

    /* Basically, prioritize what the temperature sensors
     * recommend we do, and perform that action on all the
     * fans.
     */
    list_for_each_entry(tp, &all_temps, glob_list) {
        if (tp->fan_todo[which_fan] == FAN_FULLBLAST) {
            decision = FAN_FULLBLAST;
            break;
        }
        if (tp->fan_todo[which_fan] == FAN_SAME &&
            decision != FAN_FASTER)
            decision = FAN_SAME;
        else if (tp->fan_todo[which_fan] == FAN_FASTER)
            decision = FAN_FASTER;
        else if (decision != FAN_FASTER &&
             decision != FAN_SAME &&
             tp->fan_todo[which_fan] == FAN_SLOWER)
            decision = FAN_SLOWER;
    }
    if (decision == FAN_STATE_MAX)
        decision = FAN_SAME;

    return decision;
}

static int maybe_new_ambient_fan_speed(struct bbc_fan_control *fp)
{
    enum fan_action decision = prioritize_fan_action(FAN_AMBIENT);
    int ret;

    if (decision == FAN_SAME)
        return 0;

    ret = 1;
    if (decision == FAN_FULLBLAST) {
        if (fp->system_fan_speed >= FAN_SPEED_MAX)
            ret = 0;
        else
            fp->system_fan_speed = FAN_SPEED_MAX;
    } else {
        if (decision == FAN_FASTER) {
            if (fp->system_fan_speed >= FAN_SPEED_MAX)
                ret = 0;
            else
                fp->system_fan_speed += 2;
        } else {
            int orig_speed = fp->system_fan_speed;

            if (orig_speed <= FAN_SPEED_MIN ||
                orig_speed <= (fp->cpu_fan_speed - 3))
                ret = 0;
            else
                fp->system_fan_speed -= 1;
        }
    }

    return ret;
}

static int maybe_new_cpu_fan_speed(struct bbc_fan_control *fp)
{
    enum fan_action decision = prioritize_fan_action(FAN_CPU);
    int ret;

    if (decision == FAN_SAME)
        return 0;

    ret = 1;
    if (decision == FAN_FULLBLAST) {
        if (fp->cpu_fan_speed >= FAN_SPEED_MAX)
            ret = 0;
        else
            fp->cpu_fan_speed = FAN_SPEED_MAX;
    } else {
        if (decision == FAN_FASTER) {
            if (fp->cpu_fan_speed >= FAN_SPEED_MAX)
                ret = 0;
            else {
                fp->cpu_fan_speed += 2;
                if (fp->system_fan_speed <
                    (fp->cpu_fan_speed - 3))
                    fp->system_fan_speed =
                        fp->cpu_fan_speed - 3;
            }
        } else {
            if (fp->cpu_fan_speed <= FAN_SPEED_MIN)
                ret = 0;
            else
                fp->cpu_fan_speed -= 1;
        }
    }

    return ret;
}

static void maybe_new_fan_speeds(struct bbc_fan_control *fp)
{
    int new;

    new  = maybe_new_ambient_fan_speed(fp);
    new |= maybe_new_cpu_fan_speed(fp);

    if (new)
        set_fan_speeds(fp);
}

static void fans_full_blast(void)
{
    struct bbc_fan_control *fp;

    /* Since we will not be monitoring things anymore, put
     * the fans on full blast.
     */
    list_for_each_entry(fp, &all_fans, glob_list) {
        fp->cpu_fan_speed = FAN_SPEED_MAX;
        fp->system_fan_speed = FAN_SPEED_MAX;
        fp->psupply_fan_on = 1;
        set_fan_speeds(fp);
    }
}

#define POLL_INTERVAL   (5 * 1000)
static unsigned long last_warning_jiffies;
static struct task_struct *kenvctrld_task;

static int kenvctrld(void *__unused)
{
    printk(KERN_INFO "bbc_envctrl: kenvctrld starting...\n");
    last_warning_jiffies = jiffies - WARN_INTERVAL;
    for (;;) {
        struct bbc_cpu_temperature *tp;
        struct bbc_fan_control *fp;

        msleep_interruptible(POLL_INTERVAL);
        if (kthread_should_stop())
            break;

        list_for_each_entry(tp, &all_temps, glob_list) {
            get_current_temps(tp);
            analyze_temps(tp, &last_warning_jiffies);
        }
        list_for_each_entry(fp, &all_fans, glob_list)
            maybe_new_fan_speeds(fp);
    }
    printk(KERN_INFO "bbc_envctrl: kenvctrld exiting...\n");

    fans_full_blast();

    return 0;
}

static void attach_one_temp(struct bbc_i2c_bus *bp, struct platform_device *op,
                int temp_idx)
{
    struct bbc_cpu_temperature *tp;

    tp = kzalloc(sizeof(*tp), GFP_KERNEL);
    if (!tp)
        return;

    tp->client = bbc_i2c_attach(bp, op);
    if (!tp->client) {
        kfree(tp);
        return;
    }


    tp->index = temp_idx;

    list_add(&tp->glob_list, &all_temps);
    list_add(&tp->bp_list, &bp->temps);

    /* Tell it to convert once every 5 seconds, clear all cfg
     * bits.
     */
    bbc_i2c_writeb(tp->client, 0x00, MAX1617_WR_CFG_BYTE);
    bbc_i2c_writeb(tp->client, 0x02, MAX1617_WR_CVRATE_BYTE);

    /* Program the hard temperature limits into the chip. */
    bbc_i2c_writeb(tp->client, amb_temp_limits[tp->index].high_pwroff,
               MAX1617_WR_AMB_HIGHLIM);
    bbc_i2c_writeb(tp->client, amb_temp_limits[tp->index].low_pwroff,
               MAX1617_WR_AMB_LOWLIM);
    bbc_i2c_writeb(tp->client, cpu_temp_limits[tp->index].high_pwroff,
               MAX1617_WR_CPU_HIGHLIM);
    bbc_i2c_writeb(tp->client, cpu_temp_limits[tp->index].low_pwroff,
               MAX1617_WR_CPU_LOWLIM);

    get_current_temps(tp);
    tp->prev_cpu_temp = tp->avg_cpu_temp = tp->curr_cpu_temp;
    tp->prev_amb_temp = tp->avg_amb_temp = tp->curr_amb_temp;

    tp->fan_todo[FAN_AMBIENT] = FAN_SAME;
    tp->fan_todo[FAN_CPU] = FAN_SAME;
}

static void attach_one_fan(struct bbc_i2c_bus *bp, struct platform_device *op,
               int fan_idx)
{
    struct bbc_fan_control *fp;

    fp = kzalloc(sizeof(*fp), GFP_KERNEL);
    if (!fp)
        return;

    fp->client = bbc_i2c_attach(bp, op);
    if (!fp->client) {
        kfree(fp);
        return;
    }

    fp->index = fan_idx;

    list_add(&fp->glob_list, &all_fans);
    list_add(&fp->bp_list, &bp->fans);

    /* The i2c device controlling the fans is write-only.
     * So the only way to keep track of the current power
     * level fed to the fans is via software.  Choose half
     * power for cpu/system and 'on' fo the powersupply fan
     * and set it now.
     */
    fp->psupply_fan_on = 1;
    fp->cpu_fan_speed = (FAN_SPEED_MAX - FAN_SPEED_MIN) / 2;
    fp->cpu_fan_speed += FAN_SPEED_MIN;
    fp->system_fan_speed = (FAN_SPEED_MAX - FAN_SPEED_MIN) / 2;
    fp->system_fan_speed += FAN_SPEED_MIN;

    set_fan_speeds(fp);
}

static void destroy_one_temp(struct bbc_cpu_temperature *tp)
{
    bbc_i2c_detach(tp->client);
    kfree(tp);
}

static void destroy_all_temps(struct bbc_i2c_bus *bp)
{
    struct bbc_cpu_temperature *tp, *tpos;

    list_for_each_entry_safe(tp, tpos, &bp->temps, bp_list) {
        list_del(&tp->bp_list);
        list_del(&tp->glob_list);
        destroy_one_temp(tp);
    }
}

static void destroy_one_fan(struct bbc_fan_control *fp)
{
    bbc_i2c_detach(fp->client);
    kfree(fp);
}

static void destroy_all_fans(struct bbc_i2c_bus *bp)
{
    struct bbc_fan_control *fp, *fpos;

    list_for_each_entry_safe(fp, fpos, &bp->fans, bp_list) {
        list_del(&fp->bp_list);
        list_del(&fp->glob_list);
        destroy_one_fan(fp);
    }
}

int bbc_envctrl_init(struct bbc_i2c_bus *bp)
{
    struct platform_device *op;
    int temp_index = 0;
    int fan_index = 0;
    int devidx = 0;

    while ((op = bbc_i2c_getdev(bp, devidx++)) != NULL) {
        if (!strcmp(op->dev.of_node->name, "temperature"))
            attach_one_temp(bp, op, temp_index++);
        if (!strcmp(op->dev.of_node->name, "fan-control"))
            attach_one_fan(bp, op, fan_index++);
    }
    if (temp_index != 0 && fan_index != 0) {
        kenvctrld_task = kthread_run(kenvctrld, NULL, "kenvctrld");
        if (IS_ERR(kenvctrld_task)) {
            int err = PTR_ERR(kenvctrld_task);

            kenvctrld_task = NULL;
            destroy_all_temps(bp);
            destroy_all_fans(bp);
            return err;
        }
    }

    return 0;
}

void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp)
{
    if (kenvctrld_task)
        kthread_stop(kenvctrld_task);

    destroy_all_temps(bp);
    destroy_all_fans(bp);
}