envctrl.c

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/* envctrl.c: Temperature and Fan monitoring on Machines providing it.
 *
 * Copyright (C) 1998  Eddie C. Dost  ([email protected])
 * Copyright (C) 2000  Vinh Truong    ([email protected])
 * VT - The implementation is to support Sun Microelectronics (SME) platform
 *      environment monitoring.  SME platforms use pcf8584 as the i2c bus 
 *      controller to access pcf8591 (8-bit A/D and D/A converter) and 
 *      pcf8571 (256 x 8-bit static low-voltage RAM with I2C-bus interface).
 *      At board level, it follows SME Firmware I2C Specification. Reference:
 *  http://www-eu2.semiconductors.com/pip/PCF8584P
 *  http://www-eu2.semiconductors.com/pip/PCF8574AP
 *  http://www-eu2.semiconductors.com/pip/PCF8591P
 *
 * EB - Added support for CP1500 Global Address and PS/Voltage monitoring.
 *      Eric Brower <[email protected]>
 *
 * DB - Audit every copy_to_user in envctrl_read.
 *              Daniele Bellucci <[email protected]>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/miscdevice.h>
#include <linux/kmod.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>

#include <asm/uaccess.h>
#include <asm/envctrl.h>
#include <asm/io.h>

#define DRIVER_NAME "envctrl"
#define PFX     DRIVER_NAME ": "

#define ENVCTRL_MINOR   162

#define PCF8584_ADDRESS 0x55

#define CONTROL_PIN 0x80
#define CONTROL_ES0 0x40
#define CONTROL_ES1 0x20
#define CONTROL_ES2 0x10
#define CONTROL_ENI 0x08
#define CONTROL_STA 0x04
#define CONTROL_STO 0x02
#define CONTROL_ACK 0x01

#define STATUS_PIN  0x80
#define STATUS_STS  0x20
#define STATUS_BER  0x10
#define STATUS_LRB  0x08
#define STATUS_AD0  0x08
#define STATUS_AAB  0x04
#define STATUS_LAB  0x02
#define STATUS_BB   0x01

/*
 * CLK Mode Register.
 */
#define BUS_CLK_90  0x00
#define BUS_CLK_45  0x01
#define BUS_CLK_11  0x02
#define BUS_CLK_1_5 0x03

#define CLK_3       0x00
#define CLK_4_43    0x10
#define CLK_6       0x14
#define CLK_8       0x18
#define CLK_12      0x1c

#define OBD_SEND_START  0xc5    /* value to generate I2c_bus START condition */
#define OBD_SEND_STOP   0xc3    /* value to generate I2c_bus STOP condition */

/* Monitor type of i2c child device.
 * Firmware definitions.
 */
#define PCF8584_MAX_CHANNELS            8
#define PCF8584_GLOBALADDR_TYPE         6  /* global address monitor */
#define PCF8584_FANSTAT_TYPE            3  /* fan status monitor */
#define PCF8584_VOLTAGE_TYPE            2  /* voltage monitor    */
#define PCF8584_TEMP_TYPE               1  /* temperature monitor*/

/* Monitor type of i2c child device.
 * Driver definitions.
 */
#define ENVCTRL_NOMON               0
#define ENVCTRL_CPUTEMP_MON         1    /* cpu temperature monitor */
#define ENVCTRL_CPUVOLTAGE_MON      2    /* voltage monitor         */
#define ENVCTRL_FANSTAT_MON         3    /* fan status monitor      */
#define ENVCTRL_ETHERTEMP_MON       4    /* ethernet temperature */
                         /* monitor                     */
#define ENVCTRL_VOLTAGESTAT_MON     5    /* voltage status monitor  */
#define ENVCTRL_MTHRBDTEMP_MON      6    /* motherboard temperature */
#define ENVCTRL_SCSITEMP_MON        7    /* scsi temperature */
#define ENVCTRL_GLOBALADDR_MON      8    /* global address */

/* Child device type.
 * Driver definitions.
 */
#define I2C_ADC             0    /* pcf8591 */
#define I2C_GPIO            1    /* pcf8571 */

/* Data read from child device may need to decode
 * through a data table and a scale.
 * Translation type as defined by firmware.
 */
#define ENVCTRL_TRANSLATE_NO        0
#define ENVCTRL_TRANSLATE_PARTIAL   1
#define ENVCTRL_TRANSLATE_COMBINED  2
#define ENVCTRL_TRANSLATE_FULL      3     /* table[data] */
#define ENVCTRL_TRANSLATE_SCALE     4     /* table[data]/scale */

/* Driver miscellaneous definitions. */
#define ENVCTRL_MAX_CPU         4
#define CHANNEL_DESC_SZ         256

/* Mask values for combined GlobalAddress/PowerStatus node */
#define ENVCTRL_GLOBALADDR_ADDR_MASK    0x1F
#define ENVCTRL_GLOBALADDR_PSTAT_MASK   0x60

/* Node 0x70 ignored on CompactPCI CP1400/1500 platforms 
 * (see envctrl_init_i2c_child)
 */
#define ENVCTRL_CPCI_IGNORED_NODE       0x70

#define PCF8584_DATA    0x00
#define PCF8584_CSR 0x01

/* Each child device can be monitored by up to PCF8584_MAX_CHANNELS.
 * Property of a port or channel as defined by the firmware.
 */
struct pcf8584_channel {
        unsigned char chnl_no;
        unsigned char io_direction;
        unsigned char type;
        unsigned char last;
};

/* Each child device may have one or more tables of bytes to help decode
 * data. Table property as defined by the firmware.
 */ 
struct pcf8584_tblprop {
        unsigned int type;
        unsigned int scale;  
        unsigned int offset; /* offset from the beginning of the table */
        unsigned int size;
};

/* i2c child */
struct i2c_child_t {
    /* Either ADC or GPIO. */
    unsigned char i2ctype;
        unsigned long addr;    
        struct pcf8584_channel chnl_array[PCF8584_MAX_CHANNELS];

    /* Channel info. */ 
    unsigned int total_chnls;   /* Number of monitor channels. */
    unsigned char fan_mask;     /* Byte mask for fan status channels. */
    unsigned char voltage_mask; /* Byte mask for voltage status channels. */
        struct pcf8584_tblprop tblprop_array[PCF8584_MAX_CHANNELS];

    /* Properties of all monitor channels. */
    unsigned int total_tbls;    /* Number of monitor tables. */
        char *tables;           /* Pointer to table(s). */
    char chnls_desc[CHANNEL_DESC_SZ]; /* Channel description. */
    char mon_type[PCF8584_MAX_CHANNELS];
};

static void __iomem *i2c;
static struct i2c_child_t i2c_childlist[ENVCTRL_MAX_CPU*2];
static unsigned char chnls_mask[] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 };
static unsigned int warning_temperature = 0;
static unsigned int shutdown_temperature = 0;
static char read_cpu;

/* Forward declarations. */
static struct i2c_child_t *envctrl_get_i2c_child(unsigned char);

/* Function Description: Test the PIN bit (Pending Interrupt Not) 
 *           to test when serial transmission is completed .
 * Return : None.
 */
static void envtrl_i2c_test_pin(void)
{
    int limit = 1000000;

    while (--limit > 0) {
        if (!(readb(i2c + PCF8584_CSR) & STATUS_PIN)) 
            break;
        udelay(1);
    } 

    if (limit <= 0)
        printk(KERN_INFO PFX "Pin status will not clear.\n");
}

/* Function Description: Test busy bit.
 * Return : None.
 */
static void envctrl_i2c_test_bb(void)
{
    int limit = 1000000;

    while (--limit > 0) {
        /* Busy bit 0 means busy. */
        if (readb(i2c + PCF8584_CSR) & STATUS_BB)
            break;
        udelay(1);
    } 

    if (limit <= 0)
        printk(KERN_INFO PFX "Busy bit will not clear.\n");
}

/* Function Description: Send the address for a read access.
 * Return : 0 if not acknowledged, otherwise acknowledged.
 */
static int envctrl_i2c_read_addr(unsigned char addr)
{
    envctrl_i2c_test_bb();

    /* Load address. */
    writeb(addr + 1, i2c + PCF8584_DATA);

    envctrl_i2c_test_bb();

    writeb(OBD_SEND_START, i2c + PCF8584_CSR);

    /* Wait for PIN. */
    envtrl_i2c_test_pin();

    /* CSR 0 means acknowledged. */
    if (!(readb(i2c + PCF8584_CSR) & STATUS_LRB)) {
        return readb(i2c + PCF8584_DATA);
    } else {
        writeb(OBD_SEND_STOP, i2c + PCF8584_CSR);
        return 0;
    }
}

/* Function Description: Send the address for write mode.  
 * Return : None.
 */
static void envctrl_i2c_write_addr(unsigned char addr)
{
    envctrl_i2c_test_bb();
    writeb(addr, i2c + PCF8584_DATA);

    /* Generate Start condition. */
    writeb(OBD_SEND_START, i2c + PCF8584_CSR);
}

/* Function Description: Read 1 byte of data from addr 
 *           set by envctrl_i2c_read_addr() 
 * Return : Data from address set by envctrl_i2c_read_addr().
 */
static unsigned char envctrl_i2c_read_data(void)
{
    envtrl_i2c_test_pin();
    writeb(CONTROL_ES0, i2c + PCF8584_CSR);  /* Send neg ack. */
    return readb(i2c + PCF8584_DATA);
}

/* Function Description: Instruct the device which port to read data from.  
 * Return : None.
 */
static void envctrl_i2c_write_data(unsigned char port)
{
    envtrl_i2c_test_pin();
    writeb(port, i2c + PCF8584_DATA);
}

/* Function Description: Generate Stop condition after last byte is sent.
 * Return : None.
 */
static void envctrl_i2c_stop(void)
{
    envtrl_i2c_test_pin();
    writeb(OBD_SEND_STOP, i2c + PCF8584_CSR);
}

/* Function Description: Read adc device.
 * Return : Data at address and port.
 */
static unsigned char envctrl_i2c_read_8591(unsigned char addr, unsigned char port)
{
    /* Send address. */
    envctrl_i2c_write_addr(addr);

    /* Setup port to read. */
    envctrl_i2c_write_data(port);
    envctrl_i2c_stop();

    /* Read port. */
    envctrl_i2c_read_addr(addr);

    /* Do a single byte read and send stop. */
    envctrl_i2c_read_data();
    envctrl_i2c_stop();

    return readb(i2c + PCF8584_DATA);
}

/* Function Description: Read gpio device.
 * Return : Data at address.
 */
static unsigned char envctrl_i2c_read_8574(unsigned char addr)
{
    unsigned char rd;

    envctrl_i2c_read_addr(addr);

    /* Do a single byte read and send stop. */
    rd = envctrl_i2c_read_data();
    envctrl_i2c_stop();
    return rd;
}

/* Function Description: Decode data read from an adc device using firmware
 *                       table.
 * Return: Number of read bytes. Data is stored in bufdata in ascii format.
 */
static int envctrl_i2c_data_translate(unsigned char data, int translate_type,
                      int scale, char *tbl, char *bufdata)
{
    int len = 0;

    switch (translate_type) {
    case ENVCTRL_TRANSLATE_NO:
        /* No decode necessary. */
        len = 1;
        bufdata[0] = data;
        break;

    case ENVCTRL_TRANSLATE_FULL:
        /* Decode this way: data = table[data]. */
        len = 1;
        bufdata[0] = tbl[data];
        break;

    case ENVCTRL_TRANSLATE_SCALE:
        /* Decode this way: data = table[data]/scale */
        sprintf(bufdata,"%d ", (tbl[data] * 10) / (scale));
        len = strlen(bufdata);
        bufdata[len - 1] = bufdata[len - 2];
        bufdata[len - 2] = '.';
        break;

    default:
        break;
    }

    return len;
}

/* Function Description: Read cpu-related data such as cpu temperature, voltage.
 * Return: Number of read bytes. Data is stored in bufdata in ascii format.
 */
static int envctrl_read_cpu_info(int cpu, struct i2c_child_t *pchild,
                 char mon_type, unsigned char *bufdata)
{
    unsigned char data;
    int i;
    char *tbl, j = -1;

    /* Find the right monitor type and channel. */
    for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
        if (pchild->mon_type[i] == mon_type) {
            if (++j == cpu) {
                break;
            }
        }
    }

    if (j != cpu)
        return 0;

        /* Read data from address and port. */
    data = envctrl_i2c_read_8591((unsigned char)pchild->addr,
                     (unsigned char)pchild->chnl_array[i].chnl_no);

    /* Find decoding table. */
    tbl = pchild->tables + pchild->tblprop_array[i].offset;

    return envctrl_i2c_data_translate(data, pchild->tblprop_array[i].type,
                      pchild->tblprop_array[i].scale,
                      tbl, bufdata);
}

/* Function Description: Read noncpu-related data such as motherboard 
 *                       temperature.
 * Return: Number of read bytes. Data is stored in bufdata in ascii format.
 */
static int envctrl_read_noncpu_info(struct i2c_child_t *pchild,
                    char mon_type, unsigned char *bufdata)
{
    unsigned char data;
    int i;
    char *tbl = NULL;

    for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
        if (pchild->mon_type[i] == mon_type)
            break;
    }

    if (i >= PCF8584_MAX_CHANNELS)
        return 0;

        /* Read data from address and port. */
    data = envctrl_i2c_read_8591((unsigned char)pchild->addr,
                     (unsigned char)pchild->chnl_array[i].chnl_no);

    /* Find decoding table. */
    tbl = pchild->tables + pchild->tblprop_array[i].offset;

    return envctrl_i2c_data_translate(data, pchild->tblprop_array[i].type,
                      pchild->tblprop_array[i].scale,
                      tbl, bufdata);
}

/* Function Description: Read fan status.
 * Return : Always 1 byte. Status stored in bufdata.
 */
static int envctrl_i2c_fan_status(struct i2c_child_t *pchild,
                  unsigned char data,
                  char *bufdata)
{
    unsigned char tmp, ret = 0;
    int i, j = 0;

    tmp = data & pchild->fan_mask;

    if (tmp == pchild->fan_mask) {
        /* All bits are on. All fans are functioning. */
        ret = ENVCTRL_ALL_FANS_GOOD;
    } else if (tmp == 0) {
        /* No bits are on. No fans are functioning. */
        ret = ENVCTRL_ALL_FANS_BAD;
    } else {
        /* Go through all channels, mark 'on' the matched bits.
         * Notice that fan_mask may have discontiguous bits but
         * return mask are always contiguous. For example if we
         * monitor 4 fans at channels 0,1,2,4, the return mask
         * should be 00010000 if only fan at channel 4 is working.
         */
        for (i = 0; i < PCF8584_MAX_CHANNELS;i++) {
            if (pchild->fan_mask & chnls_mask[i]) {
                if (!(chnls_mask[i] & tmp))
                    ret |= chnls_mask[j];

                j++;
            }
        }
    }

    bufdata[0] = ret;
    return 1;
}

/* Function Description: Read global addressing line.
 * Return : Always 1 byte. Status stored in bufdata.
 */
static int envctrl_i2c_globaladdr(struct i2c_child_t *pchild,
                  unsigned char data,
                  char *bufdata)
{
    /* Translatation table is not necessary, as global
     * addr is the integer value of the GA# bits.
     *
     * NOTE: MSB is documented as zero, but I see it as '1' always....
     *
     * -----------------------------------------------
     * | 0 | FAL | DEG | GA4 | GA3 | GA2 | GA1 | GA0 |
     * -----------------------------------------------
     * GA0 - GA4    integer value of Global Address (backplane slot#)
     * DEG          0 = cPCI Power supply output is starting to degrade
     *              1 = cPCI Power supply output is OK
     * FAL          0 = cPCI Power supply has failed
     *              1 = cPCI Power supply output is OK
     */
    bufdata[0] = (data & ENVCTRL_GLOBALADDR_ADDR_MASK);
    return 1;
}

/* Function Description: Read standard voltage and power supply status.
 * Return : Always 1 byte. Status stored in bufdata.
 */
static unsigned char envctrl_i2c_voltage_status(struct i2c_child_t *pchild,
                        unsigned char data,
                        char *bufdata)
{
    unsigned char tmp, ret = 0;
    int i, j = 0;

    tmp = data & pchild->voltage_mask;

    /* Two channels are used to monitor voltage and power supply. */
    if (tmp == pchild->voltage_mask) {
        /* All bits are on. Voltage and power supply are okay. */
        ret = ENVCTRL_VOLTAGE_POWERSUPPLY_GOOD;
    } else if (tmp == 0) {
        /* All bits are off. Voltage and power supply are bad */
        ret = ENVCTRL_VOLTAGE_POWERSUPPLY_BAD;
    } else {
        /* Either voltage or power supply has problem. */
        for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
            if (pchild->voltage_mask & chnls_mask[i]) {
                j++;

                /* Break out when there is a mismatch. */
                if (!(chnls_mask[i] & tmp))
                    break; 
            }
        }

        /* Make a wish that hardware will always use the
         * first channel for voltage and the second for
         * power supply.
         */
        if (j == 1)
            ret = ENVCTRL_VOLTAGE_BAD;
        else
            ret = ENVCTRL_POWERSUPPLY_BAD;
    }

    bufdata[0] = ret;
    return 1;
}

/* Function Description: Read a byte from /dev/envctrl. Mapped to user read().
 * Return: Number of read bytes. 0 for error.
 */
static ssize_t
envctrl_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
    struct i2c_child_t *pchild;
    unsigned char data[10];
    int ret = 0;

    /* Get the type of read as decided in ioctl() call.
     * Find the appropriate i2c child.
     * Get the data and put back to the user buffer.
     */

    switch ((int)(long)file->private_data) {
    case ENVCTRL_RD_WARNING_TEMPERATURE:
        if (warning_temperature == 0)
            return 0;

        data[0] = (unsigned char)(warning_temperature);
        ret = 1;
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_SHUTDOWN_TEMPERATURE:
        if (shutdown_temperature == 0)
            return 0;

        data[0] = (unsigned char)(shutdown_temperature);
        ret = 1;
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_MTHRBD_TEMPERATURE:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_MTHRBDTEMP_MON)))
            return 0;
        ret = envctrl_read_noncpu_info(pchild, ENVCTRL_MTHRBDTEMP_MON, data);
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_CPU_TEMPERATURE:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_CPUTEMP_MON)))
            return 0;
        ret = envctrl_read_cpu_info(read_cpu, pchild, ENVCTRL_CPUTEMP_MON, data);

        /* Reset cpu to the default cpu0. */
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_CPU_VOLTAGE:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_CPUVOLTAGE_MON)))
            return 0;
        ret = envctrl_read_cpu_info(read_cpu, pchild, ENVCTRL_CPUVOLTAGE_MON, data);

        /* Reset cpu to the default cpu0. */
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_SCSI_TEMPERATURE:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_SCSITEMP_MON)))
            return 0;
        ret = envctrl_read_noncpu_info(pchild, ENVCTRL_SCSITEMP_MON, data);
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_ETHERNET_TEMPERATURE:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_ETHERTEMP_MON)))
            return 0;
        ret = envctrl_read_noncpu_info(pchild, ENVCTRL_ETHERTEMP_MON, data);
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_FAN_STATUS:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_FANSTAT_MON)))
            return 0;
        data[0] = envctrl_i2c_read_8574(pchild->addr);
        ret = envctrl_i2c_fan_status(pchild,data[0], data);
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;
    
    case ENVCTRL_RD_GLOBALADDRESS:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_GLOBALADDR_MON)))
            return 0;
        data[0] = envctrl_i2c_read_8574(pchild->addr);
        ret = envctrl_i2c_globaladdr(pchild, data[0], data);
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    case ENVCTRL_RD_VOLTAGE_STATUS:
        if (!(pchild = envctrl_get_i2c_child(ENVCTRL_VOLTAGESTAT_MON)))
            /* If voltage monitor not present, check for CPCI equivalent */
            if (!(pchild = envctrl_get_i2c_child(ENVCTRL_GLOBALADDR_MON)))
                return 0;
        data[0] = envctrl_i2c_read_8574(pchild->addr);
        ret = envctrl_i2c_voltage_status(pchild, data[0], data);
        if (copy_to_user(buf, data, ret))
            ret = -EFAULT;
        break;

    default:
        break;

    }

    return ret;
}

/* Function Description: Command what to read.  Mapped to user ioctl().
 * Return: Gives 0 for implemented commands, -EINVAL otherwise.
 */
static long
envctrl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    char __user *infobuf;

    switch (cmd) {
    case ENVCTRL_RD_WARNING_TEMPERATURE:
    case ENVCTRL_RD_SHUTDOWN_TEMPERATURE:
    case ENVCTRL_RD_MTHRBD_TEMPERATURE:
    case ENVCTRL_RD_FAN_STATUS:
    case ENVCTRL_RD_VOLTAGE_STATUS:
    case ENVCTRL_RD_ETHERNET_TEMPERATURE:
    case ENVCTRL_RD_SCSI_TEMPERATURE:
    case ENVCTRL_RD_GLOBALADDRESS:
        file->private_data = (void *)(long)cmd;
        break;

    case ENVCTRL_RD_CPU_TEMPERATURE:
    case ENVCTRL_RD_CPU_VOLTAGE:
        /* Check to see if application passes in any cpu number,
         * the default is cpu0.
         */
        infobuf = (char __user *) arg;
        if (infobuf == NULL) {
            read_cpu = 0;
        }else {
            get_user(read_cpu, infobuf);
        }

        /* Save the command for use when reading. */
        file->private_data = (void *)(long)cmd;
        break;

    default:
        return -EINVAL;
    }

    return 0;
}

/* Function Description: open device. Mapped to user open().
 * Return: Always 0.
 */
static int
envctrl_open(struct inode *inode, struct file *file)
{
    file->private_data = NULL;
    return 0;
}

/* Function Description: Open device. Mapped to user close().
 * Return: Always 0.
 */
static int
envctrl_release(struct inode *inode, struct file *file)
{
    return 0;
}

static const struct file_operations envctrl_fops = {
    .owner =        THIS_MODULE,
    .read =         envctrl_read,
    .unlocked_ioctl =   envctrl_ioctl,
#ifdef CONFIG_COMPAT
    .compat_ioctl =     envctrl_ioctl,
#endif
    .open =         envctrl_open,
    .release =      envctrl_release,
    .llseek =       noop_llseek,
};  

static struct miscdevice envctrl_dev = {
    ENVCTRL_MINOR,
    "envctrl",
    &envctrl_fops
};

/* Function Description: Set monitor type based on firmware description.
 * Return: None.
 */
static void envctrl_set_mon(struct i2c_child_t *pchild,
                const char *chnl_desc,
                int chnl_no)
{
    /* Firmware only has temperature type.  It does not distinguish
     * different kinds of temperatures.  We use channel description
     * to disinguish them.
     */
    if (!(strcmp(chnl_desc,"temp,cpu")) ||
        !(strcmp(chnl_desc,"temp,cpu0")) ||
        !(strcmp(chnl_desc,"temp,cpu1")) ||
        !(strcmp(chnl_desc,"temp,cpu2")) ||
        !(strcmp(chnl_desc,"temp,cpu3")))
        pchild->mon_type[chnl_no] = ENVCTRL_CPUTEMP_MON;

    if (!(strcmp(chnl_desc,"vddcore,cpu0")) ||
        !(strcmp(chnl_desc,"vddcore,cpu1")) ||
        !(strcmp(chnl_desc,"vddcore,cpu2")) ||
        !(strcmp(chnl_desc,"vddcore,cpu3")))
        pchild->mon_type[chnl_no] = ENVCTRL_CPUVOLTAGE_MON;

    if (!(strcmp(chnl_desc,"temp,motherboard")))
        pchild->mon_type[chnl_no] = ENVCTRL_MTHRBDTEMP_MON;

    if (!(strcmp(chnl_desc,"temp,scsi")))
        pchild->mon_type[chnl_no] = ENVCTRL_SCSITEMP_MON;

    if (!(strcmp(chnl_desc,"temp,ethernet")))
        pchild->mon_type[chnl_no] = ENVCTRL_ETHERTEMP_MON;
}

/* Function Description: Initialize monitor channel with channel desc,
 *                       decoding tables, monitor type, optional properties.
 * Return: None.
 */
static void envctrl_init_adc(struct i2c_child_t *pchild, struct device_node *dp)
{
    int i = 0, len;
    const char *pos;
    const unsigned int *pval;

    /* Firmware describe channels into a stream separated by a '\0'. */
    pos = of_get_property(dp, "channels-description", &len);

    while (len > 0) {
        int l = strlen(pos) + 1;
        envctrl_set_mon(pchild, pos, i++);
        len -= l;
        pos += l;
    }

    /* Get optional properties. */
    pval = of_get_property(dp, "warning-temp", NULL);
    if (pval)
        warning_temperature = *pval;

    pval = of_get_property(dp, "shutdown-temp", NULL);
    if (pval)
        shutdown_temperature = *pval;
}

/* Function Description: Initialize child device monitoring fan status.
 * Return: None.
 */
static void envctrl_init_fanstat(struct i2c_child_t *pchild)
{
    int i;

    /* Go through all channels and set up the mask. */
    for (i = 0; i < pchild->total_chnls; i++)
        pchild->fan_mask |= chnls_mask[(pchild->chnl_array[i]).chnl_no];

    /* We only need to know if this child has fan status monitored.
     * We don't care which channels since we have the mask already.
     */
    pchild->mon_type[0] = ENVCTRL_FANSTAT_MON;
}

/* Function Description: Initialize child device for global addressing line.
 * Return: None.
 */
static void envctrl_init_globaladdr(struct i2c_child_t *pchild)
{
    int i;

    /* Voltage/PowerSupply monitoring is piggybacked 
     * with Global Address on CompactPCI.  See comments
     * within envctrl_i2c_globaladdr for bit assignments.
     *
     * The mask is created here by assigning mask bits to each
     * bit position that represents PCF8584_VOLTAGE_TYPE data.
     * Channel numbers are not consecutive within the globaladdr
     * node (why?), so we use the actual counter value as chnls_mask
     * index instead of the chnl_array[x].chnl_no value.
     *
     * NOTE: This loop could be replaced with a constant representing
     * a mask of bits 5&6 (ENVCTRL_GLOBALADDR_PSTAT_MASK).
     */
    for (i = 0; i < pchild->total_chnls; i++) {
        if (PCF8584_VOLTAGE_TYPE == pchild->chnl_array[i].type) {
            pchild->voltage_mask |= chnls_mask[i];
        }
    }

    /* We only need to know if this child has global addressing 
     * line monitored.  We don't care which channels since we know 
     * the mask already (ENVCTRL_GLOBALADDR_ADDR_MASK).
     */
    pchild->mon_type[0] = ENVCTRL_GLOBALADDR_MON;
}

/* Initialize child device monitoring voltage status. */
static void envctrl_init_voltage_status(struct i2c_child_t *pchild)
{
    int i;

    /* Go through all channels and set up the mask. */
    for (i = 0; i < pchild->total_chnls; i++)
        pchild->voltage_mask |= chnls_mask[(pchild->chnl_array[i]).chnl_no];

    /* We only need to know if this child has voltage status monitored.
     * We don't care which channels since we have the mask already.
     */
    pchild->mon_type[0] = ENVCTRL_VOLTAGESTAT_MON;
}

/* Function Description: Initialize i2c child device.
 * Return: None.
 */
static void envctrl_init_i2c_child(struct device_node *dp,
                   struct i2c_child_t *pchild)
{
    int len, i, tbls_size = 0;
    const void *pval;

    /* Get device address. */
    pval = of_get_property(dp, "reg", &len);
    memcpy(&pchild->addr, pval, len);

    /* Get tables property.  Read firmware temperature tables. */
    pval = of_get_property(dp, "translation", &len);
    if (pval && len > 0) {
        memcpy(pchild->tblprop_array, pval, len);
                pchild->total_tbls = len / sizeof(struct pcf8584_tblprop);
        for (i = 0; i < pchild->total_tbls; i++) {
            if ((pchild->tblprop_array[i].size + pchild->tblprop_array[i].offset) > tbls_size) {
                tbls_size = pchild->tblprop_array[i].size + pchild->tblprop_array[i].offset;
            }
        }

                pchild->tables = kmalloc(tbls_size, GFP_KERNEL);
        if (pchild->tables == NULL){
            printk(KERN_ERR PFX "Failed to allocate table.\n");
            return;
        }
        pval = of_get_property(dp, "tables", &len);
                if (!pval || len <= 0) {
            printk(KERN_ERR PFX "Failed to get table.\n");
            return;
        }
        memcpy(pchild->tables, pval, len);
    }

    /* SPARCengine ASM Reference Manual (ref. SMI doc 805-7581-04)
     * sections 2.5, 3.5, 4.5 state node 0x70 for CP1400/1500 is
     * "For Factory Use Only."
     *
     * We ignore the node on these platforms by assigning the
     * 'NULL' monitor type.
     */
    if (ENVCTRL_CPCI_IGNORED_NODE == pchild->addr) {
        struct device_node *root_node;
        int len;

        root_node = of_find_node_by_path("/");
        if (!strcmp(root_node->name, "SUNW,UltraSPARC-IIi-cEngine")) {
            for (len = 0; len < PCF8584_MAX_CHANNELS; ++len) {
                pchild->mon_type[len] = ENVCTRL_NOMON;
            }
            return;
        }
    }

    /* Get the monitor channels. */
    pval = of_get_property(dp, "channels-in-use", &len);
    memcpy(pchild->chnl_array, pval, len);
    pchild->total_chnls = len / sizeof(struct pcf8584_channel);

    for (i = 0; i < pchild->total_chnls; i++) {
        switch (pchild->chnl_array[i].type) {
        case PCF8584_TEMP_TYPE:
            envctrl_init_adc(pchild, dp);
            break;

        case PCF8584_GLOBALADDR_TYPE:
            envctrl_init_globaladdr(pchild);
            i = pchild->total_chnls;
            break;

        case PCF8584_FANSTAT_TYPE:
            envctrl_init_fanstat(pchild);
            i = pchild->total_chnls;
            break;

        case PCF8584_VOLTAGE_TYPE:
            if (pchild->i2ctype == I2C_ADC) {
                envctrl_init_adc(pchild,dp);
            } else {
                envctrl_init_voltage_status(pchild);
            }
            i = pchild->total_chnls;
            break;

        default:
            break;
        }
    }
}

/* Function Description: Search the child device list for a device.
 * Return : The i2c child if found. NULL otherwise.
 */
static struct i2c_child_t *envctrl_get_i2c_child(unsigned char mon_type)
{
    int i, j;

    for (i = 0; i < ENVCTRL_MAX_CPU*2; i++) {
        for (j = 0; j < PCF8584_MAX_CHANNELS; j++) {
            if (i2c_childlist[i].mon_type[j] == mon_type) {
                return (struct i2c_child_t *)(&(i2c_childlist[i]));
            }
        }
    }
    return NULL;
}

static void envctrl_do_shutdown(void)
{
    static int inprog = 0;
    int ret;

    if (inprog != 0)
        return;

    inprog = 1;
    printk(KERN_CRIT "kenvctrld: WARNING: Shutting down the system now.\n");
    ret = orderly_poweroff(true);
    if (ret < 0) {
        printk(KERN_CRIT "kenvctrld: WARNING: system shutdown failed!\n"); 
        inprog = 0;  /* unlikely to succeed, but we could try again */
    }
}

static struct task_struct *kenvctrld_task;

static int kenvctrld(void *__unused)
{
    int poll_interval;
    int whichcpu;
    char tempbuf[10];
    struct i2c_child_t *cputemp;

    if (NULL == (cputemp = envctrl_get_i2c_child(ENVCTRL_CPUTEMP_MON))) {
        printk(KERN_ERR  PFX
               "kenvctrld unable to monitor CPU temp-- exiting\n");
        return -ENODEV;
    }

    poll_interval = 5000; /* TODO env_mon_interval */

    printk(KERN_INFO PFX "%s starting...\n", current->comm);
    for (;;) {
        msleep_interruptible(poll_interval);

        if (kthread_should_stop())
            break;
        
        for (whichcpu = 0; whichcpu < ENVCTRL_MAX_CPU; ++whichcpu) {
            if (0 < envctrl_read_cpu_info(whichcpu, cputemp,
                              ENVCTRL_CPUTEMP_MON,
                              tempbuf)) {
                if (tempbuf[0] >= shutdown_temperature) {
                    printk(KERN_CRIT 
                        "%s: WARNING: CPU%i temperature %i C meets or exceeds "\
                        "shutdown threshold %i C\n", 
                        current->comm, whichcpu, 
                        tempbuf[0], shutdown_temperature);
                    envctrl_do_shutdown();
                }
            }
        }
    }
    printk(KERN_INFO PFX "%s exiting...\n", current->comm);
    return 0;
}

static int __devinit envctrl_probe(struct platform_device *op)
{
    struct device_node *dp;
    int index, err;

    if (i2c)
        return -EINVAL;

    i2c = of_ioremap(&op->resource[0], 0, 0x2, DRIVER_NAME);
    if (!i2c)
        return -ENOMEM;

    index = 0;
    dp = op->dev.of_node->child;
    while (dp) {
        if (!strcmp(dp->name, "gpio")) {
            i2c_childlist[index].i2ctype = I2C_GPIO;
            envctrl_init_i2c_child(dp, &(i2c_childlist[index++]));
        } else if (!strcmp(dp->name, "adc")) {
            i2c_childlist[index].i2ctype = I2C_ADC;
            envctrl_init_i2c_child(dp, &(i2c_childlist[index++]));
        }

        dp = dp->sibling;
    }

    /* Set device address. */
    writeb(CONTROL_PIN, i2c + PCF8584_CSR);
    writeb(PCF8584_ADDRESS, i2c + PCF8584_DATA);

    /* Set system clock and SCL frequencies. */ 
    writeb(CONTROL_PIN | CONTROL_ES1, i2c + PCF8584_CSR);
    writeb(CLK_4_43 | BUS_CLK_90, i2c + PCF8584_DATA);

    /* Enable serial interface. */
    writeb(CONTROL_PIN | CONTROL_ES0 | CONTROL_ACK, i2c + PCF8584_CSR);
    udelay(200);

    /* Register the device as a minor miscellaneous device. */
    err = misc_register(&envctrl_dev);
    if (err) {
        printk(KERN_ERR PFX "Unable to get misc minor %d\n",
               envctrl_dev.minor);
        goto out_iounmap;
    }

    /* Note above traversal routine post-incremented 'i' to accommodate 
     * a next child device, so we decrement before reverse-traversal of
     * child devices.
     */
    printk(KERN_INFO PFX "Initialized ");
    for (--index; index >= 0; --index) {
        printk("[%s 0x%lx]%s", 
            (I2C_ADC == i2c_childlist[index].i2ctype) ? "adc" : 
            ((I2C_GPIO == i2c_childlist[index].i2ctype) ? "gpio" : "unknown"), 
            i2c_childlist[index].addr, (0 == index) ? "\n" : " ");
    }

    kenvctrld_task = kthread_run(kenvctrld, NULL, "kenvctrld");
    if (IS_ERR(kenvctrld_task)) {
        err = PTR_ERR(kenvctrld_task);
        goto out_deregister;
    }

    return 0;

out_deregister:
    misc_deregister(&envctrl_dev);
out_iounmap:
    of_iounmap(&op->resource[0], i2c, 0x2);
    for (index = 0; index < ENVCTRL_MAX_CPU * 2; index++)
        kfree(i2c_childlist[index].tables);

    return err;
}

static int __devexit envctrl_remove(struct platform_device *op)
{
    int index;

    kthread_stop(kenvctrld_task);

    of_iounmap(&op->resource[0], i2c, 0x2);
    misc_deregister(&envctrl_dev);

    for (index = 0; index < ENVCTRL_MAX_CPU * 2; index++)
        kfree(i2c_childlist[index].tables);

    return 0;
}

static const struct of_device_id envctrl_match[] = {
    {
        .name = "i2c",
        .compatible = "i2cpcf,8584",
    },
    {},
};
MODULE_DEVICE_TABLE(of, envctrl_match);

static struct platform_driver envctrl_driver = {
    .driver = {
        .name = DRIVER_NAME,
        .owner = THIS_MODULE,
        .of_match_table = envctrl_match,
    },
    .probe      = envctrl_probe,
    .remove     = __devexit_p(envctrl_remove),
};

module_platform_driver(envctrl_driver);

MODULE_LICENSE("GPL");