windfarm_fcu_controls.c

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/*
 * Windfarm PowerMac thermal control. FCU fan control
 *
 * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
 *
 * Released under the term of the GNU GPL v2.
 */
#undef DEBUG

#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/wait.h>
#include <linux/i2c.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/sections.h>

#include "windfarm.h"
#include "windfarm_mpu.h"

#define VERSION "1.0"

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

/*
 * This option is "weird" :) Basically, if you define this to 1
 * the control loop for the RPMs fans (not PWMs) will apply the
 * correction factor obtained from the PID to the actual RPM
 * speed read from the FCU.
 *
 * If you define the below constant to 0, then it will be
 * applied to the setpoint RPM speed, that is basically the
 * speed we proviously "asked" for.
 *
 * I'm using 0 for now which is what therm_pm72 used to do and
 * what Darwin -apparently- does based on observed behaviour.
 */
#define RPM_PID_USE_ACTUAL_SPEED    0

/* Default min/max for pumps */
#define CPU_PUMP_OUTPUT_MAX     3200
#define CPU_PUMP_OUTPUT_MIN     1250

#define FCU_FAN_RPM     0
#define FCU_FAN_PWM     1

struct wf_fcu_priv {
    struct kref     ref;
    struct i2c_client   *i2c;
    struct mutex        lock;
    struct list_head    fan_list;
    int         rpm_shift;
};

struct wf_fcu_fan {
    struct list_head    link;
    int         id;
    s32         min, max, target;
    struct wf_fcu_priv  *fcu_priv;
    struct wf_control   ctrl;
};

static void wf_fcu_release(struct kref *ref)
{
    struct wf_fcu_priv *pv = container_of(ref, struct wf_fcu_priv, ref);

    kfree(pv);
}

static void wf_fcu_fan_release(struct wf_control *ct)
{
    struct wf_fcu_fan *fan = ct->priv;

    kref_put(&fan->fcu_priv->ref, wf_fcu_release);
    kfree(fan);
}

static int wf_fcu_read_reg(struct wf_fcu_priv *pv, int reg,
               unsigned char *buf, int nb)
{
    int tries, nr, nw;

    mutex_lock(&pv->lock);

    buf[0] = reg;
    tries = 0;
    for (;;) {
        nw = i2c_master_send(pv->i2c, buf, 1);
        if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
            break;
        msleep(10);
        ++tries;
    }
    if (nw <= 0) {
        pr_err("Failure writing address to FCU: %d", nw);
        nr = nw;
        goto bail;
    }
    tries = 0;
    for (;;) {
        nr = i2c_master_recv(pv->i2c, buf, nb);
        if (nr > 0 || (nr < 0 && nr != -ENODEV) || tries >= 100)
            break;
        msleep(10);
        ++tries;
    }
    if (nr <= 0)
        pr_err("wf_fcu: Failure reading data from FCU: %d", nw);
 bail:
    mutex_unlock(&pv->lock);
    return nr;
}

static int wf_fcu_write_reg(struct wf_fcu_priv *pv, int reg,
                const unsigned char *ptr, int nb)
{
    int tries, nw;
    unsigned char buf[16];

    buf[0] = reg;
    memcpy(buf+1, ptr, nb);
    ++nb;
    tries = 0;
    for (;;) {
        nw = i2c_master_send(pv->i2c, buf, nb);
        if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
            break;
        msleep(10);
        ++tries;
    }
    if (nw < 0)
        pr_err("wf_fcu: Failure writing to FCU: %d", nw);
    return nw;
}

static int wf_fcu_fan_set_rpm(struct wf_control *ct, s32 value)
{
    struct wf_fcu_fan *fan = ct->priv;
    struct wf_fcu_priv *pv = fan->fcu_priv;
    int rc, shift = pv->rpm_shift;
    unsigned char buf[2];

    if (value < fan->min)
        value = fan->min;
    if (value > fan->max)
        value = fan->max;

    fan->target = value;

    buf[0] = value >> (8 - shift);
    buf[1] = value << shift;
    rc = wf_fcu_write_reg(pv, 0x10 + (fan->id * 2), buf, 2);
    if (rc < 0)
        return -EIO;
    return 0;
}

static int wf_fcu_fan_get_rpm(struct wf_control *ct, s32 *value)
{
    struct wf_fcu_fan *fan = ct->priv;
    struct wf_fcu_priv *pv = fan->fcu_priv;
    int rc, reg_base, shift = pv->rpm_shift;
    unsigned char failure;
    unsigned char active;
    unsigned char buf[2];

    rc = wf_fcu_read_reg(pv, 0xb, &failure, 1);
    if (rc != 1)
        return -EIO;
    if ((failure & (1 << fan->id)) != 0)
        return -EFAULT;
    rc = wf_fcu_read_reg(pv, 0xd, &active, 1);
    if (rc != 1)
        return -EIO;
    if ((active & (1 << fan->id)) == 0)
        return -ENXIO;

    /* Programmed value or real current speed */
#if RPM_PID_USE_ACTUAL_SPEED
    reg_base = 0x11;
#else
    reg_base = 0x10;
#endif
    rc = wf_fcu_read_reg(pv, reg_base + (fan->id * 2), buf, 2);
    if (rc != 2)
        return -EIO;

    *value = (buf[0] << (8 - shift)) | buf[1] >> shift;

    return 0;
}

static int wf_fcu_fan_set_pwm(struct wf_control *ct, s32 value)
{
    struct wf_fcu_fan *fan = ct->priv;
    struct wf_fcu_priv *pv = fan->fcu_priv;
    unsigned char buf[2];
    int rc;

    if (value < fan->min)
        value = fan->min;
    if (value > fan->max)
        value = fan->max;

    fan->target = value;

    value = (value * 2559) / 1000;
    buf[0] = value;
    rc = wf_fcu_write_reg(pv, 0x30 + (fan->id * 2), buf, 1);
    if (rc < 0)
        return -EIO;
    return 0;
}

static int wf_fcu_fan_get_pwm(struct wf_control *ct, s32 *value)
{
    struct wf_fcu_fan *fan = ct->priv;
    struct wf_fcu_priv *pv = fan->fcu_priv;
    unsigned char failure;
    unsigned char active;
    unsigned char buf[2];
    int rc;

    rc = wf_fcu_read_reg(pv, 0x2b, &failure, 1);
    if (rc != 1)
        return -EIO;
    if ((failure & (1 << fan->id)) != 0)
        return -EFAULT;
    rc = wf_fcu_read_reg(pv, 0x2d, &active, 1);
    if (rc != 1)
        return -EIO;
    if ((active & (1 << fan->id)) == 0)
        return -ENXIO;

    rc = wf_fcu_read_reg(pv, 0x30 + (fan->id * 2), buf, 1);
    if (rc != 1)
        return -EIO;

    *value = (((s32)buf[0]) * 1000) / 2559;

    return 0;
}

static s32 wf_fcu_fan_min(struct wf_control *ct)
{
    struct wf_fcu_fan *fan = ct->priv;

    return fan->min;
}

static s32 wf_fcu_fan_max(struct wf_control *ct)
{
    struct wf_fcu_fan *fan = ct->priv;

    return fan->max;
}

static const struct wf_control_ops wf_fcu_fan_rpm_ops = {
    .set_value  = wf_fcu_fan_set_rpm,
    .get_value  = wf_fcu_fan_get_rpm,
    .get_min    = wf_fcu_fan_min,
    .get_max    = wf_fcu_fan_max,
    .release    = wf_fcu_fan_release,
    .owner      = THIS_MODULE,
};

static const struct wf_control_ops wf_fcu_fan_pwm_ops = {
    .set_value  = wf_fcu_fan_set_pwm,
    .get_value  = wf_fcu_fan_get_pwm,
    .get_min    = wf_fcu_fan_min,
    .get_max    = wf_fcu_fan_max,
    .release    = wf_fcu_fan_release,
    .owner      = THIS_MODULE,
};

static void __devinit wf_fcu_get_pump_minmax(struct wf_fcu_fan *fan)
{
    const struct mpu_data *mpu = wf_get_mpu(0);
    u16 pump_min = 0, pump_max = 0xffff;
    u16 tmp[4];

    /* Try to fetch pumps min/max infos from eeprom */
    if (mpu) {
        memcpy(&tmp, mpu->processor_part_num, 8);
        if (tmp[0] != 0xffff && tmp[1] != 0xffff) {
            pump_min = max(pump_min, tmp[0]);
            pump_max = min(pump_max, tmp[1]);
        }
        if (tmp[2] != 0xffff && tmp[3] != 0xffff) {
            pump_min = max(pump_min, tmp[2]);
            pump_max = min(pump_max, tmp[3]);
        }
    }

    /* Double check the values, this _IS_ needed as the EEPROM on
     * some dual 2.5Ghz G5s seem, at least, to have both min & max
     * same to the same value ... (grrrr)
     */
    if (pump_min == pump_max || pump_min == 0 || pump_max == 0xffff) {
        pump_min = CPU_PUMP_OUTPUT_MIN;
        pump_max = CPU_PUMP_OUTPUT_MAX;
    }

    fan->min = pump_min;
    fan->max = pump_max;

    DBG("wf_fcu: pump min/max for %s set to: [%d..%d] RPM\n",
        fan->ctrl.name, pump_min, pump_max);
}

static void __devinit wf_fcu_get_rpmfan_minmax(struct wf_fcu_fan *fan)
{
    struct wf_fcu_priv *pv = fan->fcu_priv;
    const struct mpu_data *mpu0 = wf_get_mpu(0);
    const struct mpu_data *mpu1 = wf_get_mpu(1);

    /* Default */
    fan->min = 2400 >> pv->rpm_shift;
    fan->max = 56000 >> pv->rpm_shift;

    /* CPU fans have min/max in MPU */
    if (mpu0 && !strcmp(fan->ctrl.name, "cpu-front-fan-0")) {
        fan->min = max(fan->min, (s32)mpu0->rminn_intake_fan);
        fan->max = min(fan->max, (s32)mpu0->rmaxn_intake_fan);
        goto bail;
    }
    if (mpu1 && !strcmp(fan->ctrl.name, "cpu-front-fan-1")) {
        fan->min = max(fan->min, (s32)mpu1->rminn_intake_fan);
        fan->max = min(fan->max, (s32)mpu1->rmaxn_intake_fan);
        goto bail;
    }
    if (mpu0 && !strcmp(fan->ctrl.name, "cpu-rear-fan-0")) {
        fan->min = max(fan->min, (s32)mpu0->rminn_exhaust_fan);
        fan->max = min(fan->max, (s32)mpu0->rmaxn_exhaust_fan);
        goto bail;
    }
    if (mpu1 && !strcmp(fan->ctrl.name, "cpu-rear-fan-1")) {
        fan->min = max(fan->min, (s32)mpu1->rminn_exhaust_fan);
        fan->max = min(fan->max, (s32)mpu1->rmaxn_exhaust_fan);
        goto bail;
    }
    /* Rackmac variants, we just use mpu0 intake */
    if (!strncmp(fan->ctrl.name, "cpu-fan", 7)) {
        fan->min = max(fan->min, (s32)mpu0->rminn_intake_fan);
        fan->max = min(fan->max, (s32)mpu0->rmaxn_intake_fan);
        goto bail;
    }
 bail:
    DBG("wf_fcu: fan min/max for %s set to: [%d..%d] RPM\n",
        fan->ctrl.name, fan->min, fan->max);
}

static void __devinit wf_fcu_add_fan(struct wf_fcu_priv *pv,
                     const char *name,
                     int type, int id)
{
    struct wf_fcu_fan *fan;

    fan = kzalloc(sizeof(*fan), GFP_KERNEL);
    if (!fan)
        return;
    fan->fcu_priv = pv;
    fan->id = id;
    fan->ctrl.name = name;
    fan->ctrl.priv = fan;

    /* min/max is oddball but the code comes from
     * therm_pm72 which seems to work so ...
     */
    if (type == FCU_FAN_RPM) {
        if (!strncmp(name, "cpu-pump", strlen("cpu-pump")))
            wf_fcu_get_pump_minmax(fan);
        else
            wf_fcu_get_rpmfan_minmax(fan);
        fan->ctrl.type = WF_CONTROL_RPM_FAN;
        fan->ctrl.ops = &wf_fcu_fan_rpm_ops;
    } else {
        fan->min = 10;
        fan->max = 100;
        fan->ctrl.type = WF_CONTROL_PWM_FAN;
        fan->ctrl.ops = &wf_fcu_fan_pwm_ops;
    }

    if (wf_register_control(&fan->ctrl)) {
        pr_err("wf_fcu: Failed to register fan %s\n", name);
        kfree(fan);
        return;
    }
    list_add(&fan->link, &pv->fan_list);
    kref_get(&pv->ref);
}

static void __devinit wf_fcu_lookup_fans(struct wf_fcu_priv *pv)
{
    /* Translation of device-tree location properties to
     * windfarm fan names
     */
    static const struct {
        const char *dt_name;    /* Device-tree name */
        const char *ct_name;    /* Control name */
    } loc_trans[] = {
        { "BACKSIDE",       "backside-fan",     },
        { "SYS CTRLR FAN",  "backside-fan",     },
        { "DRIVE BAY",      "drive-bay-fan",    },
        { "SLOT",       "slots-fan",        },
        { "PCI FAN",        "slots-fan",        },
        { "CPU A INTAKE",   "cpu-front-fan-0",  },
        { "CPU A EXHAUST",  "cpu-rear-fan-0",   },
        { "CPU B INTAKE",   "cpu-front-fan-1",  },
        { "CPU B EXHAUST",  "cpu-rear-fan-1",   },
        { "CPU A PUMP",     "cpu-pump-0",       },
        { "CPU B PUMP",     "cpu-pump-1",       },
        { "CPU A 1",        "cpu-fan-a-0",      },
        { "CPU A 2",        "cpu-fan-b-0",      },
        { "CPU A 3",        "cpu-fan-c-0",      },
        { "CPU B 1",        "cpu-fan-a-1",      },
        { "CPU B 2",        "cpu-fan-b-1",      },
        { "CPU B 3",        "cpu-fan-c-1",      },
    };
    struct device_node *np = NULL, *fcu = pv->i2c->dev.of_node;
    int i;

    DBG("Looking up FCU controls in device-tree...\n");

    while ((np = of_get_next_child(fcu, np)) != NULL) {
        int id, type = -1;
        const char *loc;
        const char *name;
        const u32 *reg;

        DBG(" control: %s, type: %s\n", np->name, np->type);

        /* Detect control type */
        if (!strcmp(np->type, "fan-rpm-control") ||
            !strcmp(np->type, "fan-rpm"))
            type = FCU_FAN_RPM;
        if (!strcmp(np->type, "fan-pwm-control") ||
            !strcmp(np->type, "fan-pwm"))
            type = FCU_FAN_PWM;
        /* Only care about fans for now */
        if (type == -1)
            continue;

        /* Lookup for a matching location */
        loc = of_get_property(np, "location", NULL);
        reg = of_get_property(np, "reg", NULL);
        if (loc == NULL || reg == NULL)
            continue;
        DBG(" matching location: %s, reg: 0x%08x\n", loc, *reg);

        for (i = 0; i < ARRAY_SIZE(loc_trans); i++) {
            if (strncmp(loc, loc_trans[i].dt_name,
                    strlen(loc_trans[i].dt_name)))
                continue;
            name = loc_trans[i].ct_name;

            DBG(" location match, name: %s\n", name);

            if (type == FCU_FAN_RPM)
                id = ((*reg) - 0x10) / 2;
            else
                id = ((*reg) - 0x30) / 2;
            if (id > 7) {
                pr_warning("wf_fcu: Can't parse "
                       "fan ID in device-tree for %s\n",
                       np->full_name);
                break;
            }
            wf_fcu_add_fan(pv, name, type, id);
            break;
        }
    }
}

static void __devinit wf_fcu_default_fans(struct wf_fcu_priv *pv)
{
    /* We only support the default fans for PowerMac7,2 */
    if (!of_machine_is_compatible("PowerMac7,2"))
        return;

    wf_fcu_add_fan(pv, "backside-fan",  FCU_FAN_PWM, 1);
    wf_fcu_add_fan(pv, "drive-bay-fan", FCU_FAN_RPM, 2);
    wf_fcu_add_fan(pv, "slots-fan",     FCU_FAN_PWM, 2);
    wf_fcu_add_fan(pv, "cpu-front-fan-0",   FCU_FAN_RPM, 3);
    wf_fcu_add_fan(pv, "cpu-rear-fan-0",    FCU_FAN_RPM, 4);
    wf_fcu_add_fan(pv, "cpu-front-fan-1",   FCU_FAN_RPM, 5);
    wf_fcu_add_fan(pv, "cpu-rear-fan-1",    FCU_FAN_RPM, 6);
}

static int __devinit wf_fcu_init_chip(struct wf_fcu_priv *pv)
{
    unsigned char buf = 0xff;
    int rc;

    rc = wf_fcu_write_reg(pv, 0xe, &buf, 1);
    if (rc < 0)
        return -EIO;
    rc = wf_fcu_write_reg(pv, 0x2e, &buf, 1);
    if (rc < 0)
        return -EIO;
    rc = wf_fcu_read_reg(pv, 0, &buf, 1);
    if (rc < 0)
        return -EIO;
    pv->rpm_shift = (buf == 1) ? 2 : 3;

    pr_debug("wf_fcu: FCU Initialized, RPM fan shift is %d\n",
         pv->rpm_shift);

    return 0;
}

static int __devinit wf_fcu_probe(struct i2c_client *client,
                  const struct i2c_device_id *id)
{
    struct wf_fcu_priv *pv;

    pv = kzalloc(sizeof(*pv), GFP_KERNEL);
    if (!pv)
        return -ENOMEM;

    kref_init(&pv->ref);
    mutex_init(&pv->lock);
    INIT_LIST_HEAD(&pv->fan_list);
    pv->i2c = client;

    /*
     * First we must start the FCU which will query the
     * shift value to apply to RPMs
     */
    if (wf_fcu_init_chip(pv)) {
        pr_err("wf_fcu: Initialization failed !\n");
        kfree(pv);
        return -ENXIO;
    }

    /* First lookup fans in the device-tree */
    wf_fcu_lookup_fans(pv);

    /*
     * Older machines don't have the device-tree entries
     * we are looking for, just hard code the list
     */
    if (list_empty(&pv->fan_list))
        wf_fcu_default_fans(pv);

    /* Still no fans ? FAIL */
    if (list_empty(&pv->fan_list)) {
        pr_err("wf_fcu: Failed to find fans for your machine\n");
        kfree(pv);
        return -ENODEV;
    }

    dev_set_drvdata(&client->dev, pv);

    return 0;
}

static int __devexit wf_fcu_remove(struct i2c_client *client)
{
    struct wf_fcu_priv *pv = dev_get_drvdata(&client->dev);
    struct wf_fcu_fan *fan;

    while (!list_empty(&pv->fan_list)) {
        fan = list_first_entry(&pv->fan_list, struct wf_fcu_fan, link);
        list_del(&fan->link);
        wf_unregister_control(&fan->ctrl);
    }
    kref_put(&pv->ref, wf_fcu_release);
    return 0;
}

static const struct i2c_device_id wf_fcu_id[] = {
    { "MAC,fcu", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, wf_fcu_id);

static struct i2c_driver wf_fcu_driver = {
    .driver = {
        .name   = "wf_fcu",
    },
    .probe      = wf_fcu_probe,
    .remove     = wf_fcu_remove,
    .id_table   = wf_fcu_id,
};

static int __init wf_fcu_init(void)
{
    return i2c_add_driver(&wf_fcu_driver);
}

static void __exit wf_fcu_exit(void)
{
    i2c_del_driver(&wf_fcu_driver);
}


module_init(wf_fcu_init);
module_exit(wf_fcu_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <[email protected]>");
MODULE_DESCRIPTION("FCU control objects for PowerMacs thermal control");
MODULE_LICENSE("GPL");