/*
 * Windfarm PowerMac thermal control.
 * Control loops for machines with SMU and PPC970MP processors.
 *
 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
 * 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 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 = wf_pm112_remove,
        .driver = {
                .name = "windfarm",
        },
};

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_each_node_by_type(cpu, "cpu")
                ++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 <paulus@samba.org>");
MODULE_DESCRIPTION("Thermal control for PowerMac11,2");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:windfarm");