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/*

 * Windfarm PowerMac thermal control. iMac G5

 *

 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.

 *                    <benh@kernel.crashing.org>

 *

 * Released under the term of the GNU GPL v2.

 *

 * The algorithm used is the PID control algorithm, used the same

 * way the published Darwin code does, using the same values that

 * are present in the Darwin 8.2 snapshot property lists (note however

 * that none of the code has been re-used, it's a complete re-implementation

 *

 * The various control loops found in Darwin config file are:

 *

 * PowerMac8,1 and PowerMac8,2

 * ===========================

 *

 * System Fans control loop. Different based on models. In addition to the

 * usual PID algorithm, the control loop gets 2 additional pairs of linear

 * scaling factors (scale/offsets) expressed as 4.12 fixed point values

 * signed offset, unsigned scale)

 *

 * The targets are modified such as:

 *  - the linked control (second control) gets the target value as-is

 *    (typically the drive fan)

 *  - the main control (first control) gets the target value scaled with

 *    the first pair of factors, and is then modified as below

 *  - the value of the target of the CPU Fan control loop is retrieved,

 *    scaled with the second pair of factors, and the max of that and

 *    the scaled target is applied to the main control.

 *

 * # model_id: 2

 *   controls       : system-fan, drive-bay-fan

 *   sensors        : hd-temp

 *   PID params     : G_d = 0x15400000

 *                    G_p = 0x00200000

 *                    G_r = 0x000002fd

 *                    History = 2 entries

 *                    Input target = 0x3a0000

 *                    Interval = 5s

 *   linear-factors : offset = 0xff38 scale  = 0x0ccd

 *                    offset = 0x0208 scale  = 0x07ae

 *

 * # model_id: 3

 *   controls       : system-fan, drive-bay-fan

 *   sensors        : hd-temp

 *   PID params     : G_d = 0x08e00000

 *                    G_p = 0x00566666

 *                    G_r = 0x0000072b

 *                    History = 2 entries

 *                    Input target = 0x350000

 *                    Interval = 5s

 *   linear-factors : offset = 0xff38 scale  = 0x0ccd

 *                    offset = 0x0000 scale  = 0x0000

 *

 * # model_id: 5

 *   controls       : system-fan

 *   sensors        : hd-temp

 *   PID params     : G_d = 0x15400000

 *                    G_p = 0x00233333

 *                    G_r = 0x000002fd

 *                    History = 2 entries

 *                    Input target = 0x3a0000

 *                    Interval = 5s

 *   linear-factors : offset = 0x0000 scale  = 0x1000

 *                    offset = 0x0091 scale  = 0x0bae

 *

 * CPU Fan control loop. The loop is identical for all models. it

 * has an additional pair of scaling factor. This is used to scale the

 * systems fan control loop target result (the one before it gets scaled

 * by the System Fans control loop itself). Then, the max value of the

 * calculated target value and system fan value is sent to the fans

 *

 *   controls       : cpu-fan

 *   sensors        : cpu-temp cpu-power

 *   PID params     : From SMU sdb partition

 *   linear-factors : offset = 0xfb50 scale  = 0x1000

 *

 * CPU Slew control loop. Not implemented. The cpufreq driver in linux is

 * completely separate for now, though we could find a way to link it, either

 * as a client reacting to overtemp notifications, or directling monitoring

 * the CPU temperature

 *

 * WARNING ! The CPU control loop requires the CPU tmax for the current

 * operating point. However, we currently are completely separated from

 * the cpufreq driver and thus do not know what the current operating

 * point is. Fortunately, we also do not have any hardware supporting anything

 * but operating point 0 at the moment, thus we just peek that value directly

 * from the SDB partition. If we ever end up with actually slewing the system

 * clock and thus changing operating points, we'll have to find a way to

 * communicate with the CPU freq driver;

 *

 */

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/kernel.h>

#include <linux/delay.h>

#include <linux/slab.h>

#include <linux/init.h>

#include <linux/spinlock.h>

#include <linux/wait.h>

#include <linux/kmod.h>

#include <linux/device.h>

#include <linux/platform_device.h>

#include <asm/prom.h>

#include <asm/machdep.h>

#include <asm/io.h>

#include <asm/system.h>

#include <asm/sections.h>

#include <asm/smu.h>

#include "windfarm.h"

#include "windfarm_pid.h"

#define VERSION "0.4"

#undef DEBUG

#ifdef DEBUG

#define DBG(args...)    printk(args)

#else

#define DBG(args...)    do { } while(0)

#endif

/* define this to force CPU overtemp to 74 degree, useful for testing

 * the overtemp code

 */

#undef HACKED_OVERTEMP

static int wf_smu_mach_model;   /* machine model id */

/* Controls & sensors */

static struct wf_sensor *sensor_cpu_power;

static struct wf_sensor *sensor_cpu_temp;

static struct wf_sensor *sensor_hd_temp;

static struct wf_control *fan_cpu_main;

static struct wf_control *fan_hd;

static struct wf_control *fan_system;

static struct wf_control *cpufreq_clamp;

/* Set to kick the control loop into life */

static int wf_smu_all_controls_ok, wf_smu_all_sensors_ok, wf_smu_started;

/* Failure handling.. could be nicer */

#define FAILURE_FAN             0x01

#define FAILURE_SENSOR          0x02

#define FAILURE_OVERTEMP        0x04

static unsigned int wf_smu_failure_state;

static int wf_smu_readjust, wf_smu_skipping;

/*

 * ****** System Fans Control Loop ******

 *

 */

/* Parameters for the System Fans control loop. Parameters

 * not in this table such as interval, history size, ...

 * are common to all versions and thus hard coded for now.

 */

struct wf_smu_sys_fans_param {

        int     model_id;

        s32     itarget;

        s32     gd, gp, gr;

        s16     offset0;

        u16     scale0;

        s16     offset1;

        u16     scale1;

};

#define WF_SMU_SYS_FANS_INTERVAL        5

#define WF_SMU_SYS_FANS_HISTORY_SIZE    2

/* State data used by the system fans control loop

 */

struct wf_smu_sys_fans_state {

        int                     ticks;

        s32                     sys_setpoint;

        s32                     hd_setpoint;

        s16                     offset0;

        u16                     scale0;

        s16                     offset1;

        u16                     scale1;

        struct wf_pid_state     pid;

};

/*

 * Configs for SMU Sytem Fan control loop

 */

static struct wf_smu_sys_fans_param wf_smu_sys_all_params[] = {

        /* Model ID 2 */

        {

                .model_id       = 2,

                .itarget        = 0x3a0000,

                .gd             = 0x15400000,

                .gp             = 0x00200000,

                .gr             = 0x000002fd,

                .offset0        = 0xff38,

                .scale0         = 0x0ccd,

                .offset1        = 0x0208,

                .scale1         = 0x07ae,

        },

        /* Model ID 3 */

        {

                .model_id       = 3,

                .itarget        = 0x350000,

                .gd             = 0x08e00000,

                .gp             = 0x00566666,

                .gr             = 0x0000072b,

                .offset0        = 0xff38,

                .scale0         = 0x0ccd,

                .offset1        = 0x0000,

                .scale1         = 0x0000,

        },

        /* Model ID 5 */

        {

                .model_id       = 5,

                .itarget        = 0x3a0000,

                .gd             = 0x15400000,

                .gp             = 0x00233333,

                .gr             = 0x000002fd,

                .offset0        = 0x0000,

                .scale0         = 0x1000,

                .offset1        = 0x0091,

                .scale1         = 0x0bae,

        },

};

#define WF_SMU_SYS_FANS_NUM_CONFIGS ARRAY_SIZE(wf_smu_sys_all_params)

static struct wf_smu_sys_fans_state *wf_smu_sys_fans;

/*

 * ****** CPU Fans Control Loop ******

 *

 */

#define WF_SMU_CPU_FANS_INTERVAL        1

#define WF_SMU_CPU_FANS_MAX_HISTORY     16

#define WF_SMU_CPU_FANS_SIBLING_SCALE   0x00001000

#define WF_SMU_CPU_FANS_SIBLING_OFFSET  0xfffffb50

/* State data used by the cpu fans control loop

 */

struct wf_smu_cpu_fans_state {

        int                     ticks;

        s32                     cpu_setpoint;

        s32                     scale;

        s32                     offset;

        struct wf_cpu_pid_state pid;

};

static struct wf_smu_cpu_fans_state *wf_smu_cpu_fans;

/*

 * ***** Implementation *****

 *

 */

static void wf_smu_create_sys_fans(void)

{

        struct wf_smu_sys_fans_param *param = NULL;

        struct wf_pid_param pid_param;

        int i;

        /* First, locate the params for this model */

        for (i = 0; i < WF_SMU_SYS_FANS_NUM_CONFIGS; i++)

                if (wf_smu_sys_all_params[i].model_id == wf_smu_mach_model) {

                        param = &wf_smu_sys_all_params[i];

                        break;

                }

        /* No params found, put fans to max */

        if (param == NULL) {

                printk(KERN_WARNING "windfarm: System fan config not found "

                       "for this machine model, max fan speed\n");

                goto fail;

        }

        /* Alloc & initialize state */

        wf_smu_sys_fans = kmalloc(sizeof(struct wf_smu_sys_fans_state),

                                  GFP_KERNEL);

        if (wf_smu_sys_fans == NULL) {

                printk(KERN_WARNING "windfarm: Memory allocation error"

                       " max fan speed\n");

                goto fail;

        }

        wf_smu_sys_fans->ticks = 1;

        wf_smu_sys_fans->scale0 = param->scale0;

        wf_smu_sys_fans->offset0 = param->offset0;

        wf_smu_sys_fans->scale1 = param->scale1;

        wf_smu_sys_fans->offset1 = param->offset1;

        /* Fill PID params */

        pid_param.gd = param->gd;

        pid_param.gp = param->gp;

        pid_param.gr = param->gr;

        pid_param.interval = WF_SMU_SYS_FANS_INTERVAL;

        pid_param.history_len = WF_SMU_SYS_FANS_HISTORY_SIZE;

        pid_param.itarget = param->itarget;

        pid_param.min = fan_system->ops->get_min(fan_system);

        pid_param.max = fan_system->ops->get_max(fan_system);

        if (fan_hd) {

                pid_param.min =

                        max(pid_param.min,fan_hd->ops->get_min(fan_hd));

                pid_param.max =

                        min(pid_param.max,fan_hd->ops->get_max(fan_hd));

        }

        wf_pid_init(&wf_smu_sys_fans->pid, &pid_param);

        DBG("wf: System Fan control initialized.\n");

        DBG("    itarged=%d.%03d, min=%d RPM, max=%d RPM\n",

            FIX32TOPRINT(pid_param.itarget), pid_param.min, pid_param.max);

        return;

 fail:

        if (fan_system)

                wf_control_set_max(fan_system);

        if (fan_hd)

                wf_control_set_max(fan_hd);

}

static void wf_smu_sys_fans_tick(struct wf_smu_sys_fans_state *st)

{

        s32 new_setpoint, temp, scaled, cputarget;

        int rc;

        if (--st->ticks != 0) {

                if (wf_smu_readjust)

                        goto readjust;

                return;

        }

        st->ticks = WF_SMU_SYS_FANS_INTERVAL;

        rc = sensor_hd_temp->ops->get_value(sensor_hd_temp, &temp);

        if (rc) {

                printk(KERN_WARNING "windfarm: HD temp sensor error %d\n",

                       rc);

                wf_smu_failure_state |= FAILURE_SENSOR;

                return;

        }

        DBG("wf_smu: System Fans tick ! HD temp: %d.%03d\n",

            FIX32TOPRINT(temp));

        if (temp > (st->pid.param.itarget + 0x50000))

                wf_smu_failure_state |= FAILURE_OVERTEMP;

        new_setpoint = wf_pid_run(&st->pid, temp);

        DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);

        scaled = ((((s64)new_setpoint) * (s64)st->scale0) >> 12) + st->offset0;

        DBG("wf_smu: scaled setpoint: %d RPM\n", (int)scaled);

        cputarget = wf_smu_cpu_fans ? wf_smu_cpu_fans->pid.target : 0;

        cputarget = ((((s64)cputarget) * (s64)st->scale1) >> 12) + st->offset1;

        scaled = max(scaled, cputarget);

        scaled = max(scaled, st->pid.param.min);

        scaled = min(scaled, st->pid.param.max);

        DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)scaled);

        if (st->sys_setpoint == scaled && new_setpoint == st->hd_setpoint)

                return;

        st->sys_setpoint = scaled;

        st->hd_setpoint = new_setpoint;

 readjust:

        if (fan_system && wf_smu_failure_state == 0) {

                rc = fan_system->ops->set_value(fan_system, st->sys_setpoint);

                if (rc) {

                        printk(KERN_WARNING "windfarm: Sys fan error %d\n",

                               rc);

                        wf_smu_failure_state |= FAILURE_FAN;

                }

        }

        if (fan_hd && wf_smu_failure_state == 0) {

                rc = fan_hd->ops->set_value(fan_hd, st->hd_setpoint);

                if (rc) {

                        printk(KERN_WARNING "windfarm: HD fan error %d\n",

                               rc);

                        wf_smu_failure_state |= FAILURE_FAN;

                }

        }

}

static void wf_smu_create_cpu_fans(void)

{

        struct wf_cpu_pid_param pid_param;

        const struct smu_sdbp_header *hdr;

        struct smu_sdbp_cpupiddata *piddata;

        struct smu_sdbp_fvt *fvt;

        s32 tmax, tdelta, maxpow, powadj;

        /* First, locate the PID params in SMU SBD */

        hdr = smu_get_sdb_partition(SMU_SDB_CPUPIDDATA_ID, NULL);

        if (hdr == 0) {

                printk(KERN_WARNING "windfarm: CPU PID fan config not found "

                       "max fan speed\n");

                goto fail;

        }

        piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];

        /* Get the FVT params for operating point 0 (the only supported one

         * for now) in order to get tmax

         */

        hdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);

        if (hdr) {

                fvt = (struct smu_sdbp_fvt *)&hdr[1];

                tmax = ((s32)fvt->maxtemp) << 16;

        } else

                tmax = 0x5e0000; /* 94 degree default */

        /* Alloc & initialize state */

        wf_smu_cpu_fans = kmalloc(sizeof(struct wf_smu_cpu_fans_state),

                                  GFP_KERNEL);

        if (wf_smu_cpu_fans == NULL)

                goto fail;

        wf_smu_cpu_fans->ticks = 1;

        wf_smu_cpu_fans->scale = WF_SMU_CPU_FANS_SIBLING_SCALE;

        wf_smu_cpu_fans->offset = WF_SMU_CPU_FANS_SIBLING_OFFSET;

        /* Fill PID params */

        pid_param.interval = WF_SMU_CPU_FANS_INTERVAL;

        pid_param.history_len = piddata->history_len;

        if (pid_param.history_len > WF_CPU_PID_MAX_HISTORY) {

                printk(KERN_WARNING "windfarm: History size overflow on "

                       "CPU control loop (%d)\n", piddata->history_len);

                pid_param.history_len = WF_CPU_PID_MAX_HISTORY;

        }

        pid_param.gd = piddata->gd;

        pid_param.gp = piddata->gp;

        pid_param.gr = piddata->gr / pid_param.history_len;

        tdelta = ((s32)piddata->target_temp_delta) << 16;

        maxpow = ((s32)piddata->max_power) << 16;

        powadj = ((s32)piddata->power_adj) << 16;

        pid_param.tmax = tmax;

        pid_param.ttarget = tmax - tdelta;

        pid_param.pmaxadj = maxpow - powadj;

        pid_param.min = fan_cpu_main->ops->get_min(fan_cpu_main);

        pid_param.max = fan_cpu_main->ops->get_max(fan_cpu_main);

        wf_cpu_pid_init(&wf_smu_cpu_fans->pid, &pid_param);

        DBG("wf: CPU Fan control initialized.\n");

        DBG("    ttarged=%d.%03d, tmax=%d.%03d, min=%d RPM, max=%d RPM\n",

            FIX32TOPRINT(pid_param.ttarget), FIX32TOPRINT(pid_param.tmax),

            pid_param.min, pid_param.max);

        return;

 fail:

        printk(KERN_WARNING "windfarm: CPU fan config not found\n"

               "for this machine model, max fan speed\n");

        if (cpufreq_clamp)

                wf_control_set_max(cpufreq_clamp);

        if (fan_cpu_main)

                wf_control_set_max(fan_cpu_main);

}

static void wf_smu_cpu_fans_tick(struct wf_smu_cpu_fans_state *st)

{

        s32 new_setpoint, temp, power, systarget;

        int rc;

        if (--st->ticks != 0) {

                if (wf_smu_readjust)

                        goto readjust;

                return;

        }

        st->ticks = WF_SMU_CPU_FANS_INTERVAL;

        rc = sensor_cpu_temp->ops->get_value(sensor_cpu_temp, &temp);

        if (rc) {

                printk(KERN_WARNING "windfarm: CPU temp sensor error %d\n",

                       rc);

                wf_smu_failure_state |= FAILURE_SENSOR;

                return;

        }

        rc = sensor_cpu_power->ops->get_value(sensor_cpu_power, &power);

        if (rc) {

                printk(KERN_WARNING "windfarm: CPU power sensor error %d\n",

                       rc);

                wf_smu_failure_state |= FAILURE_SENSOR;

                return;

        }

        DBG("wf_smu: CPU Fans tick ! CPU temp: %d.%03d, power: %d.%03d\n",

            FIX32TOPRINT(temp), FIX32TOPRINT(power));

#ifdef HACKED_OVERTEMP

        if (temp > 0x4a0000)

                wf_smu_failure_state |= FAILURE_OVERTEMP;

#else

        if (temp > st->pid.param.tmax)

                wf_smu_failure_state |= FAILURE_OVERTEMP;

#endif

        new_setpoint = wf_cpu_pid_run(&st->pid, power, temp);

        DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);

        systarget = wf_smu_sys_fans ? wf_smu_sys_fans->pid.target : 0;

        systarget = ((((s64)systarget) * (s64)st->scale) >> 12)

                + st->offset;

        new_setpoint = max(new_setpoint, systarget);

        new_setpoint = max(new_setpoint, st->pid.param.min);

        new_setpoint = min(new_setpoint, st->pid.param.max);

        DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)new_setpoint);

        if (st->cpu_setpoint == new_setpoint)

                return;

        st->cpu_setpoint = new_setpoint;

 readjust:

        if (fan_cpu_main && wf_smu_failure_state == 0) {

                rc = fan_cpu_main->ops->set_value(fan_cpu_main,

                                                  st->cpu_setpoint);

                if (rc) {

                        printk(KERN_WARNING "windfarm: CPU main fan"

                               " error %d\n", rc);

                        wf_smu_failure_state |= FAILURE_FAN;

                }

        }

}

/*

 * ****** Setup / Init / Misc ... ******

 *

 */

static void wf_smu_tick(void)

{

        unsigned int last_failure = wf_smu_failure_state;

        unsigned int new_failure;

        if (!wf_smu_started) {

                DBG("wf: creating control loops !\n");

                wf_smu_create_sys_fans();

                wf_smu_create_cpu_fans();

                wf_smu_started = 1;

        }

        /* Skipping ticks */

        if (wf_smu_skipping && --wf_smu_skipping)

                return;

        wf_smu_failure_state = 0;

        if (wf_smu_sys_fans)

                wf_smu_sys_fans_tick(wf_smu_sys_fans);

        if (wf_smu_cpu_fans)

                wf_smu_cpu_fans_tick(wf_smu_cpu_fans);

        wf_smu_readjust = 0;

        new_failure = wf_smu_failure_state & ~last_failure;

        /* If entering failure mode, clamp cpufreq and ramp all

         * fans to full speed.

         */

        if (wf_smu_failure_state && !last_failure) {

                if (cpufreq_clamp)

                        wf_control_set_max(cpufreq_clamp);

                if (fan_system)

                        wf_control_set_max(fan_system);

                if (fan_cpu_main)

                        wf_control_set_max(fan_cpu_main);

                if (fan_hd)

                        wf_control_set_max(fan_hd);

        }

        /* If leaving failure mode, unclamp cpufreq and readjust

         * all fans on next iteration

         */

        if (!wf_smu_failure_state && last_failure) {

                if (cpufreq_clamp)

                        wf_control_set_min(cpufreq_clamp);

                wf_smu_readjust = 1;

        }

        /* Overtemp condition detected, notify and start skipping a couple

         * ticks to let the temperature go down

         */

        if (new_failure & FAILURE_OVERTEMP) {

                wf_set_overtemp();

                wf_smu_skipping = 2;

        }

        /* We only clear the overtemp condition if overtemp is cleared

         * _and_ no other failure is present. Since a sensor error will

         * clear the overtemp condition (can't measure temperature) at

         * the control loop levels, but we don't want to keep it clear

         * here in this case

         */

        if (new_failure == 0 && last_failure & FAILURE_OVERTEMP)

                wf_clear_overtemp();

}

static void wf_smu_new_control(struct wf_control *ct)

{

        if (wf_smu_all_controls_ok)

                return;

        if (fan_cpu_main == NULL && !strcmp(ct->name, "cpu-fan")) {

                if (wf_get_control(ct) == 0)

                        fan_cpu_main = ct;

        }

        if (fan_system == NULL && !strcmp(ct->name, "system-fan")) {

                if (wf_get_control(ct) == 0)

                        fan_system = ct;

        }

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

                if (wf_get_control(ct) == 0)

                        cpufreq_clamp = ct;

        }

        /* Darwin property list says the HD fan is only for model ID

         * 0, 1, 2 and 3

         */

        if (wf_smu_mach_model > 3) {

                if (fan_system && fan_cpu_main && cpufreq_clamp)

                        wf_smu_all_controls_ok = 1;

                return;

        }

        if (fan_hd == NULL && !strcmp(ct->name, "drive-bay-fan")) {

                if (wf_get_control(ct) == 0)

                        fan_hd = ct;

        }

        if (fan_system && fan_hd && fan_cpu_main && cpufreq_clamp)

                wf_smu_all_controls_ok = 1;

}

static void wf_smu_new_sensor(struct wf_sensor *sr)

{

        if (wf_smu_all_sensors_ok)

                return;

        if (sensor_cpu_power == NULL && !strcmp(sr->name, "cpu-power")) {

                if (wf_get_sensor(sr) == 0)

                        sensor_cpu_power = sr;

        }

        if (sensor_cpu_temp == NULL && !strcmp(sr->name, "cpu-temp")) {

                if (wf_get_sensor(sr) == 0)

                        sensor_cpu_temp = sr;

        }

        if (sensor_hd_temp == NULL && !strcmp(sr->name, "hd-temp")) {

                if (wf_get_sensor(sr) == 0)

                        sensor_hd_temp = sr;

        }

        if (sensor_cpu_power && sensor_cpu_temp && sensor_hd_temp)

                wf_smu_all_sensors_ok = 1;

}

static int wf_smu_notify(struct notifier_block *self,

                               unsigned long event, void *data)

{

        switch(event) {

        case WF_EVENT_NEW_CONTROL:

                DBG("wf: new control %s detected\n",

                    ((struct wf_control *)data)->name);

                wf_smu_new_control(data);

                wf_smu_readjust = 1;

                break;

        case WF_EVENT_NEW_SENSOR:

                DBG("wf: new sensor %s detected\n",

                    ((struct wf_sensor *)data)->name);

                wf_smu_new_sensor(data);

                break;

        case WF_EVENT_TICK:

                if (wf_smu_all_controls_ok && wf_smu_all_sensors_ok)

                        wf_smu_tick();

        }

        return 0;

}

static struct notifier_block wf_smu_events = {

        .notifier_call  = wf_smu_notify,

};

static int wf_init_pm(void)

{