/*
 * Device driver for the thermostats & fan controller of  the
 * Apple G5 "PowerMac7,2" desktop machines.
 *
 * (c) Copyright IBM Corp. 2003-2004
 *
 * Maintained by: Benjamin Herrenschmidt
 *                <benh@kernel.crashing.org>
 * 
 *
 * 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 7.0 snapshot property lists.
 *
 * As far as the CPUs control loops are concerned, I use the
 * calibration & PID constants provided by the EEPROM,
 * I do _not_ embed any value from the property lists, as the ones
 * provided by Darwin 7.0 seem to always have an older version that
 * what I've seen on the actual computers.
 * It would be interesting to verify that though. Darwin has a
 * version code of 1.0.0d11 for all control loops it seems, while
 * so far, the machines EEPROMs contain a dataset versioned 1.0.0f
 *
 * Darwin doesn't provide source to all parts, some missing
 * bits like the AppleFCU driver or the actual scale of some
 * of the values returned by sensors had to be "guessed" some
 * way... or based on what Open Firmware does.
 *
 * I didn't yet figure out how to get the slots power consumption
 * out of the FCU, so that part has not been implemented yet and
 * the slots fan is set to a fixed 50% PWM, hoping this value is
 * safe enough ...
 *
 * Note: I have observed strange oscillations of the CPU control
 * loop on a dual G5 here. When idle, the CPU exhaust fan tend to
 * oscillates slowly (over several minutes) between the minimum
 * of 300RPMs and approx. 1000 RPMs. I don't know what is causing
 * this, it could be some incorrect constant or an error in the
 * way I ported the algorithm, or it could be just normal. I
 * don't have full understanding on the way Apple tweaked the PID
 * algorithm for the CPU control, it is definitely not a standard
 * implementation...
 *
 * TODO:  - Check MPU structure version/signature
 *        - Add things like /sbin/overtemp for non-critical
 *          overtemp conditions so userland can take some policy
 *          decisions, like slowing down CPUs
 *        - Deal with fan and i2c failures in a better way
 *        - Maybe do a generic PID based on params used for
 *          U3 and Drives ? Definitely need to factor code a bit
 *          better... also make sensor detection more robust using
 *          the device-tree to probe for them
 *        - Figure out how to get the slots consumption and set the
 *          slots fan accordingly
 *
 * History:
 *
 *  Nov. 13, 2003 : 0.5
 *      - First release
 *
 *  Nov. 14, 2003 : 0.6
 *      - Read fan speed from FCU, low level fan routines now deal
 *        with errors & check fan status, though higher level don't
 *        do much.
 *      - Move a bunch of definitions to .h file
 *
 *  Nov. 18, 2003 : 0.7
 *      - Fix build on ppc64 kernel
 *      - Move back statics definitions to .c file
 *      - Avoid calling schedule_timeout with a negative number
 *
 *  Dec. 18, 2003 : 0.8
 *      - Fix typo when reading back fan speed on 2 CPU machines
 *
 *  Mar. 11, 2004 : 0.9
 *      - Rework code accessing the ADC chips, make it more robust and
 *        closer to the chip spec. Also make sure it is configured properly,
 *        I've seen yet unexplained cases where on startup, I would have stale
 *        values in the configuration register
 *      - Switch back to use of target fan speed for PID, thus lowering
 *        pressure on i2c
 *
 *  Oct. 20, 2004 : 1.1
 *      - Add device-tree lookup for fan IDs, should detect liquid cooling
 *        pumps when present
 *      - Enable driver for PowerMac7,3 machines
 *      - Split the U3/Backside cooling on U3 & U3H versions as Darwin does
 *      - Add new CPU cooling algorithm for machines with liquid cooling
 *      - Workaround for some PowerMac7,3 with empty "fan" node in the devtree
 *      - Fix a signed/unsigned compare issue in some PID loops
 *
 *  Mar. 10, 2005 : 1.2
 *      - Add basic support for Xserve G5
 *      - Retrieve pumps min/max from EEPROM image in device-tree (broken)
 *      - Use min/max macros here or there
 *      - Latest darwin updated U3H min fan speed to 20% PWM
 *
 *  July. 06, 2006 : 1.3
 *      - Fix setting of RPM fans on Xserve G5 (they were going too fast)
 *      - Add missing slots fan control loop for Xserve G5
 *      - Lower fixed slots fan speed from 50% to 40% on desktop G5s. We
 *        still can't properly implement the control loop for these, so let's
 *        reduce the noise a little bit, it appears that 40% still gives us
 *        a pretty good air flow
 *      - Add code to "tickle" the FCU regulary so it doesn't think that
 *        we are gone while in fact, the machine just didn't need any fan
 *        speed change lately
 *
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/reboot.h>
#include <linux/kmod.h>
#include <linux/i2c.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/sections.h>
#include <asm/macio.h>

#include "therm_pm72.h"

#define VERSION "1.3"

#undef DEBUG

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


/*
 * Driver statics
 */

static struct platform_device *         of_dev;
static struct i2c_adapter *             u3_0;
static struct i2c_adapter *             u3_1;
static struct i2c_adapter *             k2;
static struct i2c_client *              fcu;
static struct cpu_pid_state             processor_state[2];
static struct basckside_pid_params      backside_params;
static struct backside_pid_state        backside_state;
static struct drives_pid_state          drives_state;
static struct dimm_pid_state            dimms_state;
static struct slots_pid_state           slots_state;
static int                              state;
static int                              cpu_count;
static int                              cpu_pid_type;
static struct task_struct               *ctrl_task;
static struct completion                ctrl_complete;
static int                              critical_state;
static int                              rackmac;
static s32                              dimm_output_clamp;
static int                              fcu_rpm_shift;
static int                              fcu_tickle_ticks;
static DEFINE_MUTEX(driver_lock);

/*
 * We have 3 types of CPU PID control. One is "split" old style control
 * for intake & exhaust fans, the other is "combined" control for both
 * CPUs that also deals with the pumps when present. To be "compatible"
 * with OS X at this point, we only use "COMBINED" on the machines that
 * are identified as having the pumps (though that identification is at
 * least dodgy). Ultimately, we could probably switch completely to this
 * algorithm provided we hack it to deal with the UP case
 */
#define CPU_PID_TYPE_SPLIT      0
#define CPU_PID_TYPE_COMBINED   1
#define CPU_PID_TYPE_RACKMAC    2

/*
 * This table describes all fans in the FCU. The "id" and "type" values
 * are defaults valid for all earlier machines. Newer machines will
 * eventually override the table content based on the device-tree
 */
struct fcu_fan_table
{
        char*   loc;    /* location code */
        int     type;   /* 0 = rpm, 1 = pwm, 2 = pump */
        int     id;     /* id or -1 */
};

#define FCU_FAN_RPM             0
#define FCU_FAN_PWM             1

#define FCU_FAN_ABSENT_ID       -1

#define FCU_FAN_COUNT           ARRAY_SIZE(fcu_fans)

struct fcu_fan_table    fcu_fans[] = {
        [BACKSIDE_FAN_PWM_INDEX] = {
                .loc    = "BACKSIDE,SYS CTRLR FAN",
                .type   = FCU_FAN_PWM,
                .id     = BACKSIDE_FAN_PWM_DEFAULT_ID,
        },
        [DRIVES_FAN_RPM_INDEX] = {
                .loc    = "DRIVE BAY",
                .type   = FCU_FAN_RPM,
                .id     = DRIVES_FAN_RPM_DEFAULT_ID,
        },
        [SLOTS_FAN_PWM_INDEX] = {
                .loc    = "SLOT,PCI FAN",
                .type   = FCU_FAN_PWM,
                .id     = SLOTS_FAN_PWM_DEFAULT_ID,
        },
        [CPUA_INTAKE_FAN_RPM_INDEX] = {
                .loc    = "CPU A INTAKE",
                .type   = FCU_FAN_RPM,
                .id     = CPUA_INTAKE_FAN_RPM_DEFAULT_ID,
        },
        [CPUA_EXHAUST_FAN_RPM_INDEX] = {
                .loc    = "CPU A EXHAUST",
                .type   = FCU_FAN_RPM,
                .id     = CPUA_EXHAUST_FAN_RPM_DEFAULT_ID,
        },
        [CPUB_INTAKE_FAN_RPM_INDEX] = {
                .loc    = "CPU B INTAKE",
                .type   = FCU_FAN_RPM,
                .id     = CPUB_INTAKE_FAN_RPM_DEFAULT_ID,
        },
        [CPUB_EXHAUST_FAN_RPM_INDEX] = {
                .loc    = "CPU B EXHAUST",
                .type   = FCU_FAN_RPM,
                .id     = CPUB_EXHAUST_FAN_RPM_DEFAULT_ID,
        },
        /* pumps aren't present by default, have to be looked up in the
         * device-tree
         */
        [CPUA_PUMP_RPM_INDEX] = {
                .loc    = "CPU A PUMP",
                .type   = FCU_FAN_RPM,          
                .id     = FCU_FAN_ABSENT_ID,
        },
        [CPUB_PUMP_RPM_INDEX] = {
                .loc    = "CPU B PUMP",
                .type   = FCU_FAN_RPM,
                .id     = FCU_FAN_ABSENT_ID,
        },
        /* Xserve fans */
        [CPU_A1_FAN_RPM_INDEX] = {
                .loc    = "CPU A 1",
                .type   = FCU_FAN_RPM,
                .id     = FCU_FAN_ABSENT_ID,
        },
        [CPU_A2_FAN_RPM_INDEX] = {
                .loc    = "CPU A 2",
                .type   = FCU_FAN_RPM,
                .id     = FCU_FAN_ABSENT_ID,
        },
        [CPU_A3_FAN_RPM_INDEX] = {
                .loc    = "CPU A 3",
                .type   = FCU_FAN_RPM,
                .id     = FCU_FAN_ABSENT_ID,
        },
        [CPU_B1_FAN_RPM_INDEX] = {
                .loc    = "CPU B 1",
                .type   = FCU_FAN_RPM,
                .id     = FCU_FAN_ABSENT_ID,
        },
        [CPU_B2_FAN_RPM_INDEX] = {
                .loc    = "CPU B 2",
                .type   = FCU_FAN_RPM,
                .id     = FCU_FAN_ABSENT_ID,
        },
        [CPU_B3_FAN_RPM_INDEX] = {
                .loc    = "CPU B 3",
                .type   = FCU_FAN_RPM,
                .id     = FCU_FAN_ABSENT_ID,
        },
};

static struct i2c_driver therm_pm72_driver;

/*
 * Utility function to create an i2c_client structure and
 * attach it to one of u3 adapters
 */
static struct i2c_client *attach_i2c_chip(int id, const char *name)
{
        struct i2c_client *clt;
        struct i2c_adapter *adap;
        struct i2c_board_info info;

        if (id & 0x200)
                adap = k2;
        else if (id & 0x100)
                adap = u3_1;
        else
                adap = u3_0;
        if (adap == NULL)
                return NULL;

        memset(&info, 0, sizeof(struct i2c_board_info));
        info.addr = (id >> 1) & 0x7f;
        strlcpy(info.type, "therm_pm72", I2C_NAME_SIZE);
        clt = i2c_new_device(adap, &info);
        if (!clt) {
                printk(KERN_ERR "therm_pm72: Failed to attach to i2c ID 0x%x\n", id);
                return NULL;
        }

        /*
         * Let i2c-core delete that device on driver removal.
         * This is safe because i2c-core holds the core_lock mutex for us.
         */
        list_add_tail(&clt->detected, &therm_pm72_driver.clients);
        return clt;
}

/*
 * Here are the i2c chip access wrappers
 */

static void initialize_adc(struct cpu_pid_state *state)
{
        int rc;
        u8 buf[2];

        /* Read ADC the configuration register and cache it. We
         * also make sure Config2 contains proper values, I've seen
         * cases where we got stale grabage in there, thus preventing
         * proper reading of conv. values
         */

        /* Clear Config2 */
        buf[0] = 5;
        buf[1] = 0;
        i2c_master_send(state->monitor, buf, 2);

        /* Read & cache Config1 */
        buf[0] = 1;
        rc = i2c_master_send(state->monitor, buf, 1);
        if (rc > 0) {
                rc = i2c_master_recv(state->monitor, buf, 1);
                if (rc > 0) {
                        state->adc_config = buf[0];
                        DBG("ADC config reg: %02x\n", state->adc_config);
                        /* Disable shutdown mode */
                        state->adc_config &= 0xfe;
                        buf[0] = 1;
                        buf[1] = state->adc_config;
                        rc = i2c_master_send(state->monitor, buf, 2);
                }
        }
        if (rc <= 0)
                printk(KERN_ERR "therm_pm72: Error reading ADC config"
                       " register !\n");
}

static int read_smon_adc(struct cpu_pid_state *state, int chan)
{
        int rc, data, tries = 0;
        u8 buf[2];

        for (;;) {
                /* Set channel */
                buf[0] = 1;
                buf[1] = (state->adc_config & 0x1f) | (chan << 5);
                rc = i2c_master_send(state->monitor, buf, 2);
                if (rc <= 0)
                        goto error;
                /* Wait for conversion */
                msleep(1);
                /* Switch to data register */
                buf[0] = 4;
                rc = i2c_master_send(state->monitor, buf, 1);
                if (rc <= 0)
                        goto error;
                /* Read result */
                rc = i2c_master_recv(state->monitor, buf, 2);
                if (rc < 0)
                        goto error;
                data = ((u16)buf[0]) << 8 | (u16)buf[1];
                return data >> 6;
        error:
                DBG("Error reading ADC, retrying...\n");
                if (++tries > 10) {
                        printk(KERN_ERR "therm_pm72: Error reading ADC !\n");
                        return -1;
                }
                msleep(10);
        }
}

static int read_lm87_reg(struct i2c_client * chip, int reg)
{
        int rc, tries = 0;
        u8 buf;

        for (;;) {
                /* Set address */
                buf = (u8)reg;
                rc = i2c_master_send(chip, &buf, 1);
                if (rc <= 0)
                        goto error;
                rc = i2c_master_recv(chip, &buf, 1);
                if (rc <= 0)
                        goto error;
                return (int)buf;
        error:
                DBG("Error reading LM87, retrying...\n");
                if (++tries > 10) {
                        printk(KERN_ERR "therm_pm72: Error reading LM87 !\n");
                        return -1;
                }
                msleep(10);
        }
}

static int fan_read_reg(int reg, unsigned char *buf, int nb)
{
        int tries, nr, nw;

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

static int fan_write_reg(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(fcu, buf, nb);
                if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
                        break;
                msleep(10);
                ++tries;
        }
        if (nw < 0)
                printk(KERN_ERR "Failure writing to FCU: %d", nw);
        return nw;
}

static int start_fcu(void)
{
        unsigned char buf = 0xff;
        int rc;

        rc = fan_write_reg(0xe, &buf, 1);
        if (rc < 0)
                return -EIO;
        rc = fan_write_reg(0x2e, &buf, 1);
        if (rc < 0)
                return -EIO;
        rc = fan_read_reg(0, &buf, 1);
        if (rc < 0)
                return -EIO;
        fcu_rpm_shift = (buf == 1) ? 2 : 3;
        printk(KERN_DEBUG "FCU Initialized, RPM fan shift is %d\n",
               fcu_rpm_shift);

        return 0;
}

static int set_rpm_fan(int fan_index, int rpm)
{
        unsigned char buf[2];
        int rc, id, min, max;

        if (fcu_fans[fan_index].type != FCU_FAN_RPM)
                return -EINVAL;
        id = fcu_fans[fan_index].id; 
        if (id == FCU_FAN_ABSENT_ID)
                return -EINVAL;

        min = 2400 >> fcu_rpm_shift;
        max = 56000 >> fcu_rpm_shift;

        if (rpm < min)
                rpm = min;
        else if (rpm > max)
                rpm = max;
        buf[0] = rpm >> (8 - fcu_rpm_shift);
        buf[1] = rpm << fcu_rpm_shift;
        rc = fan_write_reg(0x10 + (id * 2), buf, 2);
        if (rc < 0)
                return -EIO;
        return 0;
}

static int get_rpm_fan(int fan_index, int programmed)
{
        unsigned char failure;
        unsigned char active;
        unsigned char buf[2];
        int rc, id, reg_base;

        if (fcu_fans[fan_index].type != FCU_FAN_RPM)
                return -EINVAL;
        id = fcu_fans[fan_index].id; 
        if (id == FCU_FAN_ABSENT_ID)
                return -EINVAL;

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

        /* Programmed value or real current speed */
        reg_base = programmed ? 0x10 : 0x11;
        rc = fan_read_reg(reg_base + (id * 2), buf, 2);
        if (rc != 2)
                return -EIO;

        return (buf[0] << (8 - fcu_rpm_shift)) | buf[1] >> fcu_rpm_shift;
}

static int set_pwm_fan(int fan_index, int pwm)
{
        unsigned char buf[2];
        int rc, id;

        if (fcu_fans[fan_index].type != FCU_FAN_PWM)
                return -EINVAL;
        id = fcu_fans[fan_index].id; 
        if (id == FCU_FAN_ABSENT_ID)
                return -EINVAL;

        if (pwm < 10)
                pwm = 10;
        else if (pwm > 100)
                pwm = 100;
        pwm = (pwm * 2559) / 1000;
        buf[0] = pwm;
        rc = fan_write_reg(0x30 + (id * 2), buf, 1);
        if (rc < 0)
                return rc;
        return 0;
}

static int get_pwm_fan(int fan_index)
{
        unsigned char failure;
        unsigned char active;
        unsigned char buf[2];
        int rc, id;

        if (fcu_fans[fan_index].type != FCU_FAN_PWM)
                return -EINVAL;
        id = fcu_fans[fan_index].id; 
        if (id == FCU_FAN_ABSENT_ID)
                return -EINVAL;

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

        /* Programmed value or real current speed */
        rc = fan_read_reg(0x30 + (id * 2), buf, 1);
        if (rc != 1)
                return -EIO;

        return (buf[0] * 1000) / 2559;
}

static void tickle_fcu(void)
{
        int pwm;

        pwm = get_pwm_fan(SLOTS_FAN_PWM_INDEX);

        DBG("FCU Tickle, slots fan is: %d\n", pwm);
        if (pwm < 0)
                pwm = 100;

        if (!rackmac) {
                pwm = SLOTS_FAN_DEFAULT_PWM;
        } else if (pwm < SLOTS_PID_OUTPUT_MIN)
                pwm = SLOTS_PID_OUTPUT_MIN;

        /* That is hopefully enough to make the FCU happy */
        set_pwm_fan(SLOTS_FAN_PWM_INDEX, pwm);
}


/*
 * Utility routine to read the CPU calibration EEPROM data
 * from the device-tree
 */
static int read_eeprom(int cpu, struct mpu_data *out)
{
        struct device_node *np;
        char nodename[64];
        const u8 *data;
        int len;

        /* prom.c routine for finding a node by path is a bit brain dead
         * and requires exact @xxx unit numbers. This is a bit ugly but
         * will work for these machines
         */
        sprintf(nodename, "/u3@0,f8000000/i2c@f8001000/cpuid@a%d", cpu ? 2 : 0);
        np = of_find_node_by_path(nodename);
        if (np == NULL) {
                printk(KERN_ERR "therm_pm72: Failed to retrieve cpuid node from device-tree\n");
                return -ENODEV;
        }
        data = of_get_property(np, "cpuid", &len);
        if (data == NULL) {
                printk(KERN_ERR "therm_pm72: Failed to retrieve cpuid property from device-tree\n");
                of_node_put(np);
                return -ENODEV;
        }
        memcpy(out, data, sizeof(struct mpu_data));
        of_node_put(np);
        
        return 0;
}

static void fetch_cpu_pumps_minmax(void)
{
        struct cpu_pid_state *state0 = &processor_state[0];
        struct cpu_pid_state *state1 = &processor_state[1];
        u16 pump_min = 0, pump_max = 0xffff;
        u16 tmp[4];

        /* Try to fetch pumps min/max infos from eeprom */

        memcpy(&tmp, &state0->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;
        }

        state0->pump_min = state1->pump_min = pump_min;
        state0->pump_max = state1->pump_max = pump_max;
}

/* 
 * Now, unfortunately, sysfs doesn't give us a nice void * we could
 * pass around to the attribute functions, so we don't really have
 * choice but implement a bunch of them...
 *
 * That sucks a bit, we take the lock because FIX32TOPRINT evaluates
 * the input twice... I accept patches :)
 */
#define BUILD_SHOW_FUNC_FIX(name, data)                         \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)        \
{                                                               \
        ssize_t r;                                              \
        mutex_lock(&driver_lock);                                       \
        r = sprintf(buf, "%d.%03d", FIX32TOPRINT(data));        \
        mutex_unlock(&driver_lock);                                     \
        return r;                                               \
}
#define BUILD_SHOW_FUNC_INT(name, data)                         \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)        \
{                                                               \
        return sprintf(buf, "%d", data);                        \
}

BUILD_SHOW_FUNC_FIX(cpu0_temperature, processor_state[0].last_temp)
BUILD_SHOW_FUNC_FIX(cpu0_voltage, processor_state[0].voltage)
BUILD_SHOW_FUNC_FIX(cpu0_current, processor_state[0].current_a)
BUILD_SHOW_FUNC_INT(cpu0_exhaust_fan_rpm, processor_state[0].rpm)
BUILD_SHOW_FUNC_INT(cpu0_intake_fan_rpm, processor_state[0].intake_rpm)

BUILD_SHOW_FUNC_FIX(cpu1_temperature, processor_state[1].last_temp)
BUILD_SHOW_FUNC_FIX(cpu1_voltage, processor_state[1].voltage)
BUILD_SHOW_FUNC_FIX(cpu1_current, processor_state[1].current_a)
BUILD_SHOW_FUNC_INT(cpu1_exhaust_fan_rpm, processor_state[1].rpm)
BUILD_SHOW_FUNC_INT(cpu1_intake_fan_rpm, processor_state[1].intake_rpm)

BUILD_SHOW_FUNC_FIX(backside_temperature, backside_state.last_temp)
BUILD_SHOW_FUNC_INT(backside_fan_pwm, backside_state.pwm)

BUILD_SHOW_FUNC_FIX(drives_temperature, drives_state.last_temp)
BUILD_SHOW_FUNC_INT(drives_fan_rpm, drives_state.rpm)

BUILD_SHOW_FUNC_FIX(slots_temperature, slots_state.last_temp)
BUILD_SHOW_FUNC_INT(slots_fan_pwm, slots_state.pwm)

BUILD_SHOW_FUNC_FIX(dimms_temperature, dimms_state.last_temp)

static DEVICE_ATTR(cpu0_temperature,S_IRUGO,show_cpu0_temperature,NULL);
static DEVICE_ATTR(cpu0_voltage,S_IRUGO,show_cpu0_voltage,NULL);
static DEVICE_ATTR(cpu0_current,S_IRUGO,show_cpu0_current,NULL);
static DEVICE_ATTR(cpu0_exhaust_fan_rpm,S_IRUGO,show_cpu0_exhaust_fan_rpm,NULL);
static DEVICE_ATTR(cpu0_intake_fan_rpm,S_IRUGO,show_cpu0_intake_fan_rpm,NULL);

static DEVICE_ATTR(cpu1_temperature,S_IRUGO,show_cpu1_temperature,NULL);
static DEVICE_ATTR(cpu1_voltage,S_IRUGO,show_cpu1_voltage,NULL);
static DEVICE_ATTR(cpu1_current,S_IRUGO,show_cpu1_current,NULL);
static DEVICE_ATTR(cpu1_exhaust_fan_rpm,S_IRUGO,show_cpu1_exhaust_fan_rpm,NULL);
static DEVICE_ATTR(cpu1_intake_fan_rpm,S_IRUGO,show_cpu1_intake_fan_rpm,NULL);

static DEVICE_ATTR(backside_temperature,S_IRUGO,show_backside_temperature,NULL);
static DEVICE_ATTR(backside_fan_pwm,S_IRUGO,show_backside_fan_pwm,NULL);

static DEVICE_ATTR(drives_temperature,S_IRUGO,show_drives_temperature,NULL);
static DEVICE_ATTR(drives_fan_rpm,S_IRUGO,show_drives_fan_rpm,NULL);

static DEVICE_ATTR(slots_temperature,S_IRUGO,show_slots_temperature,NULL);
static DEVICE_ATTR(slots_fan_pwm,S_IRUGO,show_slots_fan_pwm,NULL);

static DEVICE_ATTR(dimms_temperature,S_IRUGO,show_dimms_temperature,NULL);

/*
 * CPUs fans control loop
 */

static int do_read_one_cpu_values(struct cpu_pid_state *state, s32 *temp, s32 *power)
{
        s32 ltemp, volts, amps;
        int index, rc = 0;

        /* Default (in case of error) */
        *temp = state->cur_temp;
        *power = state->cur_power;

        if (cpu_pid_type == CPU_PID_TYPE_RACKMAC)
                index = (state->index == 0) ?
                        CPU_A1_FAN_RPM_INDEX : CPU_B1_FAN_RPM_INDEX;
        else
                index = (state->index == 0) ?
                        CPUA_EXHAUST_FAN_RPM_INDEX : CPUB_EXHAUST_FAN_RPM_INDEX;

        /* Read current fan status */
        rc = get_rpm_fan(index, !RPM_PID_USE_ACTUAL_SPEED);
        if (rc < 0) {
                /* XXX What do we do now ? Nothing for now, keep old value, but
                 * return error upstream
                 */
                DBG("  cpu %d, fan reading error !\n", state->index);
        } else {
                state->rpm = rc;
                DBG("  cpu %d, exhaust RPM: %d\n", state->index, state->rpm);
        }

        /* Get some sensor readings and scale it */
        ltemp = read_smon_adc(state, 1);
        if (ltemp == -1) {
                /* XXX What do we do now ? */
                state->overtemp++;
                if (rc == 0)
                        rc = -EIO;
                DBG("  cpu %d, temp reading error !\n", state->index);
        } else {
                /* Fixup temperature according to diode calibration
                 */
                DBG("  cpu %d, temp raw: %04x, m_diode: %04x, b_diode: %04x\n",
                    state->index,
                    ltemp, state->mpu.mdiode, state->mpu.bdiode);
                *temp = ((s32)ltemp * (s32)state->mpu.mdiode + ((s32)state->mpu.bdiode << 12)) >> 2;
                state->last_temp = *temp;
                DBG("  temp: %d.%03d\n", FIX32TOPRINT((*temp)));
        }

        /*
         * Read voltage & current and calculate power
         */
        volts = read_smon_adc(state, 3);
        amps = read_smon_adc(state, 4);

        /* Scale voltage and current raw sensor values according to fixed scales
         * obtained in Darwin and calculate power from I and V
         */
        volts *= ADC_CPU_VOLTAGE_SCALE;
        amps *= ADC_CPU_CURRENT_SCALE;
        *power = (((u64)volts) * ((u64)amps)) >> 16;
        state->voltage = volts;
        state->current_a = amps;
        state->last_power = *power;

        DBG("  cpu %d, current: %d.%03d, voltage: %d.%03d, power: %d.%03d W\n",
            state->index, FIX32TOPRINT(state->current_a),
            FIX32TOPRINT(state->voltage), FIX32TOPRINT(*power));

        return 0;
}

static void do_cpu_pid(struct cpu_pid_state *state, s32 temp, s32 power)
{
        s32 power_target, integral, derivative, proportional, adj_in_target, sval;
        s64 integ_p, deriv_p, prop_p, sum; 
        int i;

        /* Calculate power target value (could be done once for all)
         * and convert to a 16.16 fp number
         */
        power_target = ((u32)(state->mpu.pmaxh - state->mpu.padjmax)) << 16;
        DBG("  power target: %d.%03d, error: %d.%03d\n",
            FIX32TOPRINT(power_target), FIX32TOPRINT(power_target - power));

        /* Store temperature and power in history array */
        state->cur_temp = (state->cur_temp + 1) % CPU_TEMP_HISTORY_SIZE;
        state->temp_history[state->cur_temp] = temp;
        state->cur_power = (state->cur_power + 1) % state->count_power;
        state->power_history[state->cur_power] = power;
        state->error_history[state->cur_power] = power_target - power;
        
        /* If first loop, fill the history table */
        if (state->first) {
                for (i = 0; i < (state->count_power - 1); i++) {
                        state->cur_power = (state->cur_power + 1) % state->count_power;
                        state->power_history[state->cur_power] = power;
                        state->error_history[state->cur_power] = power_target - power;
                }
                for (i = 0; i < (CPU_TEMP_HISTORY_SIZE - 1); i++) {
                        state->cur_temp = (state->cur_temp + 1) % CPU_TEMP_HISTORY_SIZE;
                        state->temp_history[state->cur_temp] = temp;                    
                }
                state->first = 0;
        }

        /* Calculate the integral term normally based on the "power" values */
        sum = 0;
        integral = 0;
        for (i = 0; i < state->count_power; i++)
                integral += state->error_history[i];
        integral *= CPU_PID_INTERVAL;
        DBG("  integral: %08x\n", integral);

        /* Calculate the adjusted input (sense value).
         *   G_r is 12.20
         *   integ is 16.16
         *   so the result is 28.36
         *
         * input target is mpu.ttarget, input max is mpu.tmax
         */
        integ_p = ((s64)state->mpu.pid_gr) * (s64)integral;
        DBG("   integ_p: %d\n", (int)(integ_p >> 36));
        sval = (state->mpu.tmax << 16) - ((integ_p >> 20) & 0xffffffff);
        adj_in_target = (state->mpu.ttarget << 16);
        if (adj_in_target > sval)
                adj_in_target = sval;
        DBG("   adj_in_target: %d.%03d, ttarget: %d\n", FIX32TOPRINT(adj_in_target),
            state->mpu.ttarget);

        /* Calculate the derivative term */
        derivative = state->temp_history[state->cur_temp] -
                state->temp_history[(state->cur_temp + CPU_TEMP_HISTORY_SIZE - 1)
                                    % CPU_TEMP_HISTORY_SIZE];
        derivative /= CPU_PID_INTERVAL;
        deriv_p = ((s64)state->mpu.pid_gd) * (s64)derivative;
        DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
        sum += deriv_p;

        /* Calculate the proportional term */
        proportional = temp - adj_in_target;
        prop_p = ((s64)state->mpu.pid_gp) * (s64)proportional;
        DBG("   prop_p: %d\n", (int)(prop_p >> 36));
        sum += prop_p;

        /* Scale sum */
        sum >>= 36;

        DBG("   sum: %d\n", (int)sum);
        state->rpm += (s32)sum;
}

static void do_monitor_cpu_combined(void)
{
        struct cpu_pid_state *state0 = &processor_state[0];
        struct cpu_pid_state *state1 = &processor_state[1];
        s32 temp0, power0, temp1, power1;
        s32 temp_combi, power_combi;
        int rc, intake, pump;

        rc = do_read_one_cpu_values(state0, &temp0, &power0);
        if (rc < 0) {
                /* XXX What do we do now ? */
        }
        state1->overtemp = 0;
        rc = do_read_one_cpu_values(state1, &temp1, &power1);
        if (rc < 0) {
                /* XXX What do we do now ? */
        }
        if (state1->overtemp)
                state0->overtemp++;

        temp_combi = max(temp0, temp1);
        power_combi = max(power0, power1);

        /* Check tmax, increment overtemp if we are there. At tmax+8, we go
         * full blown immediately and try to trigger a shutdown
         */
        if (temp_combi >= ((state0->mpu.tmax + 8) << 16)) {
                printk(KERN_WARNING "Warning ! Temperature way above maximum (%d) !\n",
                       temp_combi >> 16);
                state0->overtemp += CPU_MAX_OVERTEMP / 4;
        } else if (temp_combi > (state0->mpu.tmax << 16)) {
                state0->overtemp++;
                printk(KERN_WARNING "Temperature %d above max %d. overtemp %d\n",
                       temp_combi >> 16, state0->mpu.tmax, state0->overtemp);
        } else {
                if (state0->overtemp)
                        printk(KERN_WARNING "Temperature back down to %d\n",
                               temp_combi >> 16);
                state0->overtemp = 0;
        }
        if (state0->overtemp >= CPU_MAX_OVERTEMP)
                critical_state = 1;
        if (state0->overtemp > 0) {
                state0->rpm = state0->mpu.rmaxn_exhaust_fan;
                state0->intake_rpm = intake = state0->mpu.rmaxn_intake_fan;
                pump = state0->pump_max;
                goto do_set_fans;
        }

        /* Do the PID */
        do_cpu_pid(state0, temp_combi, power_combi);

        /* Range check */
        state0->rpm = max(state0->rpm, (int)state0->mpu.rminn_exhaust_fan);
        state0->rpm = min(state0->rpm, (int)state0->mpu.rmaxn_exhaust_fan);

        /* Calculate intake fan speed */
        intake = (state0->rpm * CPU_INTAKE_SCALE) >> 16;
        intake = max(intake, (int)state0->mpu.rminn_intake_fan);
        intake = min(intake, (int)state0->mpu.rmaxn_intake_fan);
        state0->intake_rpm = intake;

        /* Calculate pump speed */
        pump = (state0->rpm * state0->pump_max) /
                state0->mpu.rmaxn_exhaust_fan;
        pump = min(pump, state0->pump_max);
        pump = max(pump, state0->pump_min);
        
 do_set_fans:
        /* We copy values from state 0 to state 1 for /sysfs */
        state1->rpm = state0->rpm;
        state1->intake_rpm = state0->intake_rpm;

        DBG("** CPU %d RPM: %d Ex, %d, Pump: %d, In, overtemp: %d\n",
            state1->index, (int)state1->rpm, intake, pump, state1->overtemp);

        /* We should check for errors, shouldn't we ? But then, what
         * do we do once the error occurs ? For FCU notified fan
         * failures (-EFAULT) we probably want to notify userland
         * some way...
         */

        set_rpm_fan(CPUA_INTAKE_FAN_RPM_INDEX, intake);
        set_rpm_fan(CPUA_EXHAUST_FAN_RPM_INDEX, state0->rpm);
        set_rpm_fan(CPUB_INTAKE_FAN_RPM_INDEX, intake);
        set_rpm_fan(CPUB_EXHAUST_FAN_RPM_INDEX, state0->rpm);

        if (fcu_fans[CPUA_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID)
                set_rpm_fan(CPUA_PUMP_RPM_INDEX, pump);
        if (fcu_fans[CPUB_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID)
                set_rpm_fan(CPUB_PUMP_RPM_INDEX, pump);
}

static void do_monitor_cpu_split(struct cpu_pid_state *state)
{
        s32 temp, power;
        int rc, intake;

        /* Read current fan status */
        rc = do_read_one_cpu_values(state, &temp, &power);
        if (rc < 0) {
                /* XXX What do we do now ? */
        }

        /* Check tmax, increment overtemp if we are there. At tmax+8, we go
         * full blown immediately and try to trigger a shutdown
         */
        if (temp >= ((state->mpu.tmax + 8) << 16)) {
                printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
                       " (%d) !\n",
                       state->index, temp >> 16);
                state->overtemp += CPU_MAX_OVERTEMP / 4;
        } else if (temp > (state->mpu.tmax << 16)) {
                state->overtemp++;
                printk(KERN_WARNING "CPU %d temperature %d above max %d. overtemp %d\n",
                       state->index, temp >> 16, state->mpu.tmax, state->overtemp);
        } else {
                if (state->overtemp)
                        printk(KERN_WARNING "CPU %d temperature back down to %d\n",
                               state->index, temp >> 16);
                state->overtemp = 0;
        }
        if (state->overtemp >= CPU_MAX_OVERTEMP)
                critical_state = 1;
        if (state->overtemp > 0) {
                state->rpm = state->mpu.rmaxn_exhaust_fan;
                state->intake_rpm = intake = state->mpu.rmaxn_intake_fan;
                goto do_set_fans;
        }

        /* Do the PID */
        do_cpu_pid(state, temp, power);

        /* Range check */
        state->rpm = max(state->rpm, (int)state->mpu.rminn_exhaust_fan);
        state->rpm = min(state->rpm, (int)state->mpu.rmaxn_exhaust_fan);

        /* Calculate intake fan */
        intake = (state->rpm * CPU_INTAKE_SCALE) >> 16;
        intake = max(intake, (int)state->mpu.rminn_intake_fan);
        intake = min(intake, (int)state->mpu.rmaxn_intake_fan);
        state->intake_rpm = intake;

 do_set_fans:
        DBG("** CPU %d RPM: %d Ex, %d In, overtemp: %d\n",
            state->index, (int)state->rpm, intake, state->overtemp);

        /* We should check for errors, shouldn't we ? But then, what
         * do we do once the error occurs ? For FCU notified fan
         * failures (-EFAULT) we probably want to notify userland
         * some way...
         */
        if (state->index == 0) {
                set_rpm_fan(CPUA_INTAKE_FAN_RPM_INDEX, intake);
                set_rpm_fan(CPUA_EXHAUST_FAN_RPM_INDEX, state->rpm);
        } else {
                set_rpm_fan(CPUB_INTAKE_FAN_RPM_INDEX, intake);
                set_rpm_fan(CPUB_EXHAUST_FAN_RPM_INDEX, state->rpm);
        }
}

static void do_monitor_cpu_rack(struct cpu_pid_state *state)
{
        s32 temp, power, fan_min;
        int rc;

        /* Read current fan status */
        rc = do_read_one_cpu_values(state, &temp, &power);
        if (rc < 0) {
                /* XXX What do we do now ? */
        }

        /* Check tmax, increment overtemp if we are there. At tmax+8, we go
         * full blown immediately and try to trigger a shutdown
         */
        if (temp >= ((state->mpu.tmax + 8) << 16)) {
                printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
                       " (%d) !\n",
                       state->index, temp >> 16);
                state->overtemp = CPU_MAX_OVERTEMP / 4;
        } else if (temp > (state->mpu.tmax << 16)) {
                state->overtemp++;
                printk(KERN_WARNING "CPU %d temperature %d above max %d. overtemp %d\n",
                       state->index, temp >> 16, state->mpu.tmax, state->overtemp);
        } else {
                if (state->overtemp)
                        printk(KERN_WARNING "CPU %d temperature back down to %d\n",
                               state->index, temp >> 16);
                state->overtemp = 0;
        }
        if (state->overtemp >= CPU_MAX_OVERTEMP)
                critical_state = 1;
        if (state->overtemp > 0) {
                state->rpm = state->intake_rpm = state->mpu.rmaxn_intake_fan;
                goto do_set_fans;
        }

        /* Do the PID */
        do_cpu_pid(state, temp, power);

        /* Check clamp from dimms */
        fan_min = dimm_output_clamp;
        fan_min = max(fan_min, (int)state->mpu.rminn_intake_fan);

        DBG(" CPU min mpu = %d, min dimm = %d\n",
            state->mpu.rminn_intake_fan, dimm_output_clamp);

        state->rpm = max(state->rpm, (int)fan_min);
        state->rpm = min(state->rpm, (int)state->mpu.rmaxn_intake_fan);
        state->intake_rpm = state->rpm;

 do_set_fans:
        DBG("** CPU %d RPM: %d overtemp: %d\n",
            state->index, (int)state->rpm, state->overtemp);

        /* We should check for errors, shouldn't we ? But then, what
         * do we do once the error occurs ? For FCU notified fan
         * failures (-EFAULT) we probably want to notify userland
         * some way...
         */
        if (state->index == 0) {
                set_rpm_fan(CPU_A1_FAN_RPM_INDEX, state->rpm);
                set_rpm_fan(CPU_A2_FAN_RPM_INDEX, state->rpm);
                set_rpm_fan(CPU_A3_FAN_RPM_INDEX, state->rpm);
        } else {
                set_rpm_fan(CPU_B1_FAN_RPM_INDEX, state->rpm);
                set_rpm_fan(CPU_B2_FAN_RPM_INDEX, state->rpm);
                set_rpm_fan(CPU_B3_FAN_RPM_INDEX, state->rpm);
        }
}

/*
 * Initialize the state structure for one CPU control loop
 */
static int init_processor_state(struct cpu_pid_state *state, int index)
{
        int err;

        state->index = index;
        state->first = 1;
        state->rpm = (cpu_pid_type == CPU_PID_TYPE_RACKMAC) ? 4000 : 1000;
        state->overtemp = 0;
        state->adc_config = 0x00;


        if (index == 0)
                state->monitor = attach_i2c_chip(SUPPLY_MONITOR_ID, "CPU0_monitor");
        else if (index == 1)
                state->monitor = attach_i2c_chip(SUPPLY_MONITORB_ID, "CPU1_monitor");
        if (state->monitor == NULL)
                goto fail;

        if (read_eeprom(index, &state->mpu))
                goto fail;

        state->count_power = state->mpu.tguardband;
        if (state->count_power > CPU_POWER_HISTORY_SIZE) {
                printk(KERN_WARNING "Warning ! too many power history slots\n");
                state->count_power = CPU_POWER_HISTORY_SIZE;
        }
        DBG("CPU %d Using %d power history entries\n", index, state->count_power);

        if (index == 0) {
                err = device_create_file(&of_dev->dev, &dev_attr_cpu0_temperature);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu0_voltage);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu0_current);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu0_exhaust_fan_rpm);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu0_intake_fan_rpm);
        } else {
                err = device_create_file(&of_dev->dev, &dev_attr_cpu1_temperature);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu1_voltage);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu1_current);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu1_exhaust_fan_rpm);
                err |= device_create_file(&of_dev->dev, &dev_attr_cpu1_intake_fan_rpm);
        }
        if (err)
                printk(KERN_WARNING "Failed to create some of the attribute"
                        "files for CPU %d\n", index);

        return 0;
 fail:
        state->monitor = NULL;
        
        return -ENODEV;
}

/*
 * Dispose of the state data for one CPU control loop
 */
static void dispose_processor_state(struct cpu_pid_state *state)
{
        if (state->monitor == NULL)
                return;

        if (state->index == 0) {
                device_remove_file(&of_dev->dev, &dev_attr_cpu0_temperature);
                device_remove_file(&of_dev->dev, &dev_attr_cpu0_voltage);
                device_remove_file(&of_dev->dev, &dev_attr_cpu0_current);
                device_remove_file(&of_dev->dev, &dev_attr_cpu0_exhaust_fan_rpm);
                device_remove_file(&of_dev->dev, &dev_attr_cpu0_intake_fan_rpm);
        } else {
                device_remove_file(&of_dev->dev, &dev_attr_cpu1_temperature);
                device_remove_file(&of_dev->dev, &dev_attr_cpu1_voltage);
                device_remove_file(&of_dev->dev, &dev_attr_cpu1_current);
                device_remove_file(&of_dev->dev, &dev_attr_cpu1_exhaust_fan_rpm);
                device_remove_file(&of_dev->dev, &dev_attr_cpu1_intake_fan_rpm);
        }

        state->monitor = NULL;
}

/*
 * Motherboard backside & U3 heatsink fan control loop
 */
static void do_monitor_backside(struct backside_pid_state *state)
{
        s32 temp, integral, derivative, fan_min;
        s64 integ_p, deriv_p, prop_p, sum; 
        int i, rc;

        if (--state->ticks != 0)
                return;
        state->ticks = backside_params.interval;

        DBG("backside:\n");

        /* Check fan status */
        rc = get_pwm_fan(BACKSIDE_FAN_PWM_INDEX);
        if (rc < 0) {
                printk(KERN_WARNING "Error %d reading backside fan !\n", rc);
                /* XXX What do we do now ? */
        } else
                state->pwm = rc;
        DBG("  current pwm: %d\n", state->pwm);

        /* Get some sensor readings */
        temp = i2c_smbus_read_byte_data(state->monitor, MAX6690_EXT_TEMP) << 16;
        state->last_temp = temp;
        DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
            FIX32TOPRINT(backside_params.input_target));

        /* Store temperature and error in history array */
        state->cur_sample = (state->cur_sample + 1) % BACKSIDE_PID_HISTORY_SIZE;
        state->sample_history[state->cur_sample] = temp;
        state->error_history[state->cur_sample] = temp - backside_params.input_target;
        
        /* If first loop, fill the history table */
        if (state->first) {
                for (i = 0; i < (BACKSIDE_PID_HISTORY_SIZE - 1); i++) {
                        state->cur_sample = (state->cur_sample + 1) %
                                BACKSIDE_PID_HISTORY_SIZE;
                        state->sample_history[state->cur_sample] = temp;
                        state->error_history[state->cur_sample] =
                                temp - backside_params.input_target;
                }
                state->first = 0;
        }

        /* Calculate the integral term */
        sum = 0;
        integral = 0;
        for (i = 0; i < BACKSIDE_PID_HISTORY_SIZE; i++)
                integral += state->error_history[i];
        integral *= backside_params.interval;
        DBG("  integral: %08x\n", integral);
        integ_p = ((s64)backside_params.G_r) * (s64)integral;
        DBG("   integ_p: %d\n", (int)(integ_p >> 36));
        sum += integ_p;

        /* Calculate the derivative term */
        derivative = state->error_history[state->cur_sample] -
                state->error_history[(state->cur_sample + BACKSIDE_PID_HISTORY_SIZE - 1)
                                    % BACKSIDE_PID_HISTORY_SIZE];
        derivative /= backside_params.interval;
        deriv_p = ((s64)backside_params.G_d) * (s64)derivative;
        DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
        sum += deriv_p;

        /* Calculate the proportional term */
        prop_p = ((s64)backside_params.G_p) * (s64)(state->error_history[state->cur_sample]);
        DBG("   prop_p: %d\n", (int)(prop_p >> 36));
        sum += prop_p;

        /* Scale sum */
        sum >>= 36;

        DBG("   sum: %d\n", (int)sum);
        if (backside_params.additive)
                state->pwm += (s32)sum;
        else
                state->pwm = sum;

        /* Check for clamp */
        fan_min = (dimm_output_clamp * 100) / 14000;
        fan_min = max(fan_min, backside_params.output_min);

        state->pwm = max(state->pwm, fan_min);
        state->pwm = min(state->pwm, backside_params.output_max);

        DBG("** BACKSIDE PWM: %d\n", (int)state->pwm);
        set_pwm_fan(BACKSIDE_FAN_PWM_INDEX, state->pwm);
}

/*
 * Initialize the state structure for the backside fan control loop
 */
static int init_backside_state(struct backside_pid_state *state)
{
        struct device_node *u3;
        int u3h = 1; /* conservative by default */
        int err;

        /*
         * There are different PID params for machines with U3 and machines
         * with U3H, pick the right ones now
         */
        u3 = of_find_node_by_path("/u3@0,f8000000");
        if (u3 != NULL) {
                const u32 *vers = of_get_property(u3, "device-rev", NULL);
                if (vers)
                        if (((*vers) & 0x3f) < 0x34)
                                u3h = 0;
                of_node_put(u3);
        }

        if (rackmac) {
                backside_params.G_d = BACKSIDE_PID_RACK_G_d;
                backside_params.input_target = BACKSIDE_PID_RACK_INPUT_TARGET;
                backside_params.output_min = BACKSIDE_PID_U3H_OUTPUT_MIN;
                backside_params.interval = BACKSIDE_PID_RACK_INTERVAL;
                backside_params.G_p = BACKSIDE_PID_RACK_G_p;
                backside_params.G_r = BACKSIDE_PID_G_r;
                backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
                backside_params.additive = 0;
        } else if (u3h) {
                backside_params.G_d = BACKSIDE_PID_U3H_G_d;
                backside_params.input_target = BACKSIDE_PID_U3H_INPUT_TARGET;
                backside_params.output_min = BACKSIDE_PID_U3H_OUTPUT_MIN;
                backside_params.interval = BACKSIDE_PID_INTERVAL;
                backside_params.G_p = BACKSIDE_PID_G_p;
                backside_params.G_r = BACKSIDE_PID_G_r;
                backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
                backside_params.additive = 1;
        } else {
                backside_params.G_d = BACKSIDE_PID_U3_G_d;
                backside_params.input_target = BACKSIDE_PID_U3_INPUT_TARGET;
                backside_params.output_min = BACKSIDE_PID_U3_OUTPUT_MIN;
                backside_params.interval = BACKSIDE_PID_INTERVAL;
                backside_params.G_p = BACKSIDE_PID_G_p;
                backside_params.G_r = BACKSIDE_PID_G_r;
                backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
                backside_params.additive = 1;
        }

        state->ticks = 1;
        state->first = 1;
        state->pwm = 50;

        state->monitor = attach_i2c_chip(BACKSIDE_MAX_ID, "backside_temp");
        if (state->monitor == NULL)
                return -ENODEV;

        err = device_create_file(&of_dev->dev, &dev_attr_backside_temperature);
        err |= device_create_file(&of_dev->dev, &dev_attr_backside_fan_pwm);
        if (err)
                printk(KERN_WARNING "Failed to create attribute file(s)"
                        " for backside fan\n");

        return 0;
}

/*
 * Dispose of the state data for the backside control loop
 */
static void dispose_backside_state(struct backside_pid_state *state)
{
        if (state->monitor == NULL)
                return;

        device_remove_file(&of_dev->dev, &dev_attr_backside_temperature);
        device_remove_file(&of_dev->dev, &dev_attr_backside_fan_pwm);

        state->monitor = NULL;
}
 
/*
 * Drives bay fan control loop
 */
static void do_monitor_drives(struct drives_pid_state *state)
{
        s32 temp, integral, derivative;
        s64 integ_p, deriv_p, prop_p, sum; 
        int i, rc;

        if (--state->ticks != 0)
                return;
        state->ticks = DRIVES_PID_INTERVAL;

        DBG("drives:\n");

        /* Check fan status */
        rc = get_rpm_fan(DRIVES_FAN_RPM_INDEX, !RPM_PID_USE_ACTUAL_SPEED);
        if (rc < 0) {
                printk(KERN_WARNING "Error %d reading drives fan !\n", rc);
                /* XXX What do we do now ? */
        } else
                state->rpm = rc;
        DBG("  current rpm: %d\n", state->rpm);

        /* Get some sensor readings */
        temp = le16_to_cpu(i2c_smbus_read_word_data(state->monitor,
                                                    DS1775_TEMP)) << 8;
        state->last_temp = temp;
        DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
            FIX32TOPRINT(DRIVES_PID_INPUT_TARGET));

        /* Store temperature and error in history array */
        state->cur_sample = (state->cur_sample + 1) % DRIVES_PID_HISTORY_SIZE;
        state->sample_history[state->cur_sample] = temp;
        state->error_history[state->cur_sample] = temp - DRIVES_PID_INPUT_TARGET;
        
        /* If first loop, fill the history table */
        if (state->first) {
                for (i = 0; i < (DRIVES_PID_HISTORY_SIZE - 1); i++) {
                        state->cur_sample = (state->cur_sample + 1) %
                                DRIVES_PID_HISTORY_SIZE;
                        state->sample_history[state->cur_sample] = temp;
                        state->error_history[state->cur_sample] =
                                temp - DRIVES_PID_INPUT_TARGET;
                }
                state->first = 0;
        }

        /* Calculate the integral term */
        sum = 0;
        integral = 0;
        for (i = 0; i < DRIVES_PID_HISTORY_SIZE; i++)
                integral += state->error_history[i];
        integral *= DRIVES_PID_INTERVAL;
        DBG("  integral: %08x\n", integral);
        integ_p = ((s64)DRIVES_PID_G_r) * (s64)integral;
        DBG("   integ_p: %d\n", (int)(integ_p >> 36));
        sum += integ_p;

        /* Calculate the derivative term */
        derivative = state->error_history[state->cur_sample] -
                state->error_history[(state->cur_sample + DRIVES_PID_HISTORY_SIZE - 1)
                                    % DRIVES_PID_HISTORY_SIZE];
        derivative /= DRIVES_PID_INTERVAL;
        deriv_p = ((s64)DRIVES_PID_G_d) * (s64)derivative;
        DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
        sum += deriv_p;

        /* Calculate the proportional term */
        prop_p = ((s64)DRIVES_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
        DBG("   prop_p: %d\n", (int)(prop_p >> 36));
        sum += prop_p;

        /* Scale sum */
        sum >>= 36;

        DBG("   sum: %d\n", (int)sum);
        state->rpm += (s32)sum;

        state->rpm = max(state->rpm, DRIVES_PID_OUTPUT_MIN);
        state->rpm = min(state->rpm, DRIVES_PID_OUTPUT_MAX);

        DBG("** DRIVES RPM: %d\n", (int)state->rpm);
        set_rpm_fan(DRIVES_FAN_RPM_INDEX, state->rpm);
}

/*
 * Initialize the state structure for the drives bay fan control loop
 */
static int init_drives_state(struct drives_pid_state *state)
{
        int err;

        state->ticks = 1;
        state->first = 1;
        state->rpm = 1000;

        state->monitor = attach_i2c_chip(DRIVES_DALLAS_ID, "drives_temp");
        if (state->monitor == NULL)
                return -ENODEV;

        err = device_create_file(&of_dev->dev, &dev_attr_drives_temperature);
        err |= device_create_file(&of_dev->dev, &dev_attr_drives_fan_rpm);
        if (err)
                printk(KERN_WARNING "Failed to create attribute file(s)"
                        " for drives bay fan\n");

        return 0;
}

/*
 * Dispose of the state data for the drives control loop
 */
static void dispose_drives_state(struct drives_pid_state *state)
{
        if (state->monitor == NULL)
                return;

        device_remove_file(&of_dev->dev, &dev_attr_drives_temperature);
        device_remove_file(&of_dev->dev, &dev_attr_drives_fan_rpm);

        state->monitor = NULL;
}

/*
 * DIMMs temp control loop
 */
static void do_monitor_dimms(struct dimm_pid_state *state)
{
        s32 temp, integral, derivative, fan_min;
        s64 integ_p, deriv_p, prop_p, sum;
        int i;

        if (--state->ticks != 0)
                return;
        state->ticks = DIMM_PID_INTERVAL;

        DBG("DIMM:\n");

        DBG("  current value: %d\n", state->output);

        temp = read_lm87_reg(state->monitor, LM87_INT_TEMP);
        if (temp < 0)
                return;
        temp <<= 16;
        state->last_temp = temp;
        DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
            FIX32TOPRINT(DIMM_PID_INPUT_TARGET));

        /* Store temperature and error in history array */
        state->cur_sample = (state->cur_sample + 1) % DIMM_PID_HISTORY_SIZE;
        state->sample_history[state->cur_sample] = temp;
        state->error_history[state->cur_sample] = temp - DIMM_PID_INPUT_TARGET;

        /* If first loop, fill the history table */
        if (state->first) {
                for (i = 0; i < (DIMM_PID_HISTORY_SIZE - 1); i++) {
                        state->cur_sample = (state->cur_sample + 1) %
                                DIMM_PID_HISTORY_SIZE;
                        state->sample_history[state->cur_sample] = temp;
                        state->error_history[state->cur_sample] =
                                temp - DIMM_PID_INPUT_TARGET;
                }
                state->first = 0;
        }

        /* Calculate the integral term */
        sum = 0;
        integral = 0;
        for (i = 0; i < DIMM_PID_HISTORY_SIZE; i++)
                integral += state->error_history[i];
        integral *= DIMM_PID_INTERVAL;
        DBG("  integral: %08x\n", integral);
        integ_p = ((s64)DIMM_PID_G_r) * (s64)integral;
        DBG("   integ_p: %d\n", (int)(integ_p >> 36));
        sum += integ_p;

        /* Calculate the derivative term */
        derivative = state->error_history[state->cur_sample] -
                state->error_history[(state->cur_sample + DIMM_PID_HISTORY_SIZE - 1)
                                    % DIMM_PID_HISTORY_SIZE];
        derivative /= DIMM_PID_INTERVAL;
        deriv_p = ((s64)DIMM_PID_G_d) * (s64)derivative;
        DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
        sum += deriv_p;

        /* Calculate the proportional term */
        prop_p = ((s64)DIMM_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
        DBG("   prop_p: %d\n", (int)(prop_p >> 36));
        sum += prop_p;

        /* Scale sum */
        sum >>= 36;

        DBG("   sum: %d\n", (int)sum);
        state->output = (s32)sum;
        state->output = max(state->output, DIMM_PID_OUTPUT_MIN);
        state->output = min(state->output, DIMM_PID_OUTPUT_MAX);
        dimm_output_clamp = state->output;

        DBG("** DIMM clamp value: %d\n", (int)state->output);

        /* Backside PID is only every 5 seconds, force backside fan clamping now */
        fan_min = (dimm_output_clamp * 100) / 14000;
        fan_min = max(fan_min, backside_params.output_min);
        if (backside_state.pwm < fan_min) {
                backside_state.pwm = fan_min;
                DBG(" -> applying clamp to backside fan now: %d  !\n", fan_min);
                set_pwm_fan(BACKSIDE_FAN_PWM_INDEX, fan_min);
        }
}

/*
 * Initialize the state structure for the DIMM temp control loop
 */
static int init_dimms_state(struct dimm_pid_state *state)
{
        state->ticks = 1;
        state->first = 1;
        state->output = 4000;

        state->monitor = attach_i2c_chip(XSERVE_DIMMS_LM87, "dimms_temp");
        if (state->monitor == NULL)
                return -ENODEV;

        if (device_create_file(&of_dev->dev, &dev_attr_dimms_temperature))
                printk(KERN_WARNING "Failed to create attribute file"
                        " for DIMM temperature\n");

        return 0;
}

/*
 * Dispose of the state data for the DIMM control loop
 */
static void dispose_dimms_state(struct dimm_pid_state *state)
{
        if (state->monitor == NULL)
                return;

        device_remove_file(&of_dev->dev, &dev_attr_dimms_temperature);

        state->monitor = NULL;
}

/*
 * Slots fan control loop
 */
static void do_monitor_slots(struct slots_pid_state *state)
{
        s32 temp, integral, derivative;
        s64 integ_p, deriv_p, prop_p, sum;
        int i, rc;

        if (--state->ticks != 0)
                return;
        state->ticks = SLOTS_PID_INTERVAL;

        DBG("slots:\n");

        /* Check fan status */
        rc = get_pwm_fan(SLOTS_FAN_PWM_INDEX);
        if (rc < 0) {
                printk(KERN_WARNING "Error %d reading slots fan !\n", rc);
                /* XXX What do we do now ? */
        } else
                state->pwm = rc;
        DBG("  current pwm: %d\n", state->pwm);

        /* Get some sensor readings */
        temp = le16_to_cpu(i2c_smbus_read_word_data(state->monitor,
                                                    DS1775_TEMP)) << 8;
        state->last_temp = temp;
        DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
            FIX32TOPRINT(SLOTS_PID_INPUT_TARGET));

        /* Store temperature and error in history array */
        state->cur_sample = (state->cur_sample + 1) % SLOTS_PID_HISTORY_SIZE;
        state->sample_history[state->cur_sample] = temp;
        state->error_history[state->cur_sample] = temp - SLOTS_PID_INPUT_TARGET;

        /* If first loop, fill the history table */
        if (state->first) {
                for (i = 0; i < (SLOTS_PID_HISTORY_SIZE - 1); i++) {
                        state->cur_sample = (state->cur_sample + 1) %
                                SLOTS_PID_HISTORY_SIZE;
                        state->sample_history[state->cur_sample] = temp;
                        state->error_history[state->cur_sample] =
                                temp - SLOTS_PID_INPUT_TARGET;
                }
                state->first = 0;
        }

        /* Calculate the integral term */
        sum = 0;
        integral = 0;
        for (i = 0; i < SLOTS_PID_HISTORY_SIZE; i++)
                integral += state->error_history[i];
        integral *= SLOTS_PID_INTERVAL;
        DBG("  integral: %08x\n", integral);
        integ_p = ((s64)SLOTS_PID_G_r) * (s64)integral;
        DBG("   integ_p: %d\n", (int)(integ_p >> 36));
        sum += integ_p;

        /* Calculate the derivative term */
        derivative = state->error_history[state->cur_sample] -
                state->error_history[(state->cur_sample + SLOTS_PID_HISTORY_SIZE - 1)
                                    % SLOTS_PID_HISTORY_SIZE];
        derivative /= SLOTS_PID_INTERVAL;
        deriv_p = ((s64)SLOTS_PID_G_d) * (s64)derivative;
        DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
        sum += deriv_p;

        /* Calculate the proportional term */
        prop_p = ((s64)SLOTS_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
        DBG("   prop_p: %d\n", (int)(prop_p >> 36));
        sum += prop_p;

        /* Scale sum */
        sum >>= 36;

        DBG("   sum: %d\n", (int)sum);
        state->pwm = (s32)sum;

        state->pwm = max(state->pwm, SLOTS_PID_OUTPUT_MIN);
        state->pwm = min(state->pwm, SLOTS_PID_OUTPUT_MAX);

        DBG("** DRIVES PWM: %d\n", (int)state->pwm);
        set_pwm_fan(SLOTS_FAN_PWM_INDEX, state->pwm);
}

/*
 * Initialize the state structure for the slots bay fan control loop
 */
static int init_slots_state(struct slots_pid_state *state)
{
        int err;

        state->ticks = 1;
        state->first = 1;
        state->pwm = 50;

        state->monitor = attach_i2c_chip(XSERVE_SLOTS_LM75, "slots_temp");
        if (state->monitor == NULL)
                return -ENODEV;

        err = device_create_file(&of_dev->dev, &dev_attr_slots_temperature);
        err |= device_create_file(&of_dev->dev, &dev_attr_slots_fan_pwm);
        if (err)
                printk(KERN_WARNING "Failed to create attribute file(s)"
                        " for slots bay fan\n");

        return 0;
}

/*
 * Dispose of the state data for the slots control loop
 */
static void dispose_slots_state(struct slots_pid_state *state)
{
        if (state->monitor == NULL)
                return;

        device_remove_file(&of_dev->dev, &dev_attr_slots_temperature);
        device_remove_file(&of_dev->dev, &dev_attr_slots_fan_pwm);

        state->monitor = NULL;
}


static int call_critical_overtemp(void)
{
        char *argv[] = { critical_overtemp_path, NULL };
        static char *envp[] = { "HOME=/",
                                "TERM=linux",
                                "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                                NULL };

        return call_usermodehelper(critical_overtemp_path,
                                   argv, envp, UMH_WAIT_EXEC);
}


/*
 * Here's the kernel thread that calls the various control loops
 */
static int main_control_loop(void *x)
{
        DBG("main_control_loop started\n");

        mutex_lock(&driver_lock);

        if (start_fcu() < 0) {
                printk(KERN_ERR "kfand: failed to start FCU\n");
                mutex_unlock(&driver_lock);
                goto out;
        }

        /* Set the PCI fan once for now on non-RackMac */
        if (!rackmac)
                set_pwm_fan(SLOTS_FAN_PWM_INDEX, SLOTS_FAN_DEFAULT_PWM);

        /* Initialize ADCs */
        initialize_adc(&processor_state[0]);
        if (processor_state[1].monitor != NULL)
                initialize_adc(&processor_state[1]);

        fcu_tickle_ticks = FCU_TICKLE_TICKS;

        mutex_unlock(&driver_lock);

        while (state == state_attached) {
                unsigned long elapsed, start;

                start = jiffies;

                mutex_lock(&driver_lock);

                /* Tickle the FCU just in case */
                if (--fcu_tickle_ticks < 0) {
                        fcu_tickle_ticks = FCU_TICKLE_TICKS;
                        tickle_fcu();
                }

                /* First, we always calculate the new DIMMs state on an Xserve */
                if (rackmac)
                        do_monitor_dimms(&dimms_state);

                /* Then, the CPUs */
                if (cpu_pid_type == CPU_PID_TYPE_COMBINED)
                        do_monitor_cpu_combined();
                else if (cpu_pid_type == CPU_PID_TYPE_RACKMAC) {
                        do_monitor_cpu_rack(&processor_state[0]);
                        if (processor_state[1].monitor != NULL)
                                do_monitor_cpu_rack(&processor_state[1]);
                        // better deal with UP
                } else {
                        do_monitor_cpu_split(&processor_state[0]);
                        if (processor_state[1].monitor != NULL)
                                do_monitor_cpu_split(&processor_state[1]);
                        // better deal with UP
                }
                /* Then, the rest */
                do_monitor_backside(&backside_state);
                if (rackmac)
                        do_monitor_slots(&slots_state);
                else
                        do_monitor_drives(&drives_state);
                mutex_unlock(&driver_lock);

                if (critical_state == 1) {
                        printk(KERN_WARNING "Temperature control detected a critical condition\n");
                        printk(KERN_WARNING "Attempting to shut down...\n");
                        if (call_critical_overtemp()) {
                                printk(KERN_WARNING "Can't call %s, power off now!\n",
                                       critical_overtemp_path);
                                machine_power_off();
                        }
                }
                if (critical_state > 0)
                        critical_state++;
                if (critical_state > MAX_CRITICAL_STATE) {
                        printk(KERN_WARNING "Shutdown timed out, power off now !\n");
                        machine_power_off();
                }

                // FIXME: Deal with signals
                elapsed = jiffies - start;
                if (elapsed < HZ)
                        schedule_timeout_interruptible(HZ - elapsed);
        }

 out:
        DBG("main_control_loop ended\n");

        ctrl_task = 0;
        complete_and_exit(&ctrl_complete, 0);
}

/*
 * Dispose the control loops when tearing down
 */
static void dispose_control_loops(void)
{
        dispose_processor_state(&processor_state[0]);
        dispose_processor_state(&processor_state[1]);
        dispose_backside_state(&backside_state);
        dispose_drives_state(&drives_state);
        dispose_slots_state(&slots_state);
        dispose_dimms_state(&dimms_state);
}

/*
 * Create the control loops. U3-0 i2c bus is up, so we can now
 * get to the various sensors
 */
static int create_control_loops(void)
{
        struct device_node *np;

        /* Count CPUs from the device-tree, we don't care how many are
         * actually used by Linux
         */
        cpu_count = 0;
        for (np = NULL; NULL != (np = of_find_node_by_type(np, "cpu"));)
                cpu_count++;

        DBG("counted %d CPUs in the device-tree\n", cpu_count);

        /* Decide the type of PID algorithm to use based on the presence of
         * the pumps, though that may not be the best way, that is good enough
         * for now
         */
        if (rackmac)
                cpu_pid_type = CPU_PID_TYPE_RACKMAC;
        else if (of_machine_is_compatible("PowerMac7,3")
            && (cpu_count > 1)
            && fcu_fans[CPUA_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID
            && fcu_fans[CPUB_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID) {
                printk(KERN_INFO "Liquid cooling pumps detected, using new algorithm !\n");
                cpu_pid_type = CPU_PID_TYPE_COMBINED;
        } else
                cpu_pid_type = CPU_PID_TYPE_SPLIT;

        /* Create control loops for everything. If any fail, everything
         * fails
         */
        if (init_processor_state(&processor_state[0], 0))
                goto fail;
        if (cpu_pid_type == CPU_PID_TYPE_COMBINED)
                fetch_cpu_pumps_minmax();

        if (cpu_count > 1 && init_processor_state(&processor_state[1], 1))
                goto fail;
        if (init_backside_state(&backside_state))
                goto fail;
        if (rackmac && init_dimms_state(&dimms_state))
                goto fail;
        if (rackmac && init_slots_state(&slots_state))
                goto fail;
        if (!rackmac && init_drives_state(&drives_state))
                goto fail;

        DBG("all control loops up !\n");

        return 0;
        
 fail:
        DBG("failure creating control loops, disposing\n");

        dispose_control_loops();

        return -ENODEV;
}

/*
 * Start the control loops after everything is up, that is create
 * the thread that will make them run
 */
static void start_control_loops(void)
{
        init_completion(&ctrl_complete);

        ctrl_task = kthread_run(main_control_loop, NULL, "kfand");
}

/*
 * Stop the control loops when tearing down
 */
static void stop_control_loops(void)
{
        if (ctrl_task)
                wait_for_completion(&ctrl_complete);
}

/*
 * Attach to the i2c FCU after detecting U3-1 bus
 */
static int attach_fcu(void)
{
        fcu = attach_i2c_chip(FAN_CTRLER_ID, "fcu");
        if (fcu == NULL)
                return -ENODEV;

        DBG("FCU attached\n");

        return 0;
}

/*
 * Detach from the i2c FCU when tearing down
 */
static void detach_fcu(void)
{
        fcu = NULL;
}