windfarm_smu_sat.c

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/*
 * Windfarm PowerMac thermal control.  SMU "satellite" controller sensors.
 *
 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <[email protected]>
 *
 * Released under the terms of the GNU GPL v2.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <asm/prom.h>
#include <asm/smu.h>
#include <asm/pmac_low_i2c.h>

#include "windfarm.h"

#define VERSION "1.0"

#define DEBUG

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

/* If the cache is older than 800ms we'll refetch it */
#define MAX_AGE     msecs_to_jiffies(800)

struct wf_sat {
    struct kref     ref;
    int         nr;
    struct mutex        mutex;
    unsigned long       last_read; /* jiffies when cache last updated */
    u8          cache[16];
    struct list_head    sensors;
    struct i2c_client   *i2c;
    struct device_node  *node;
};

static struct wf_sat *sats[2];

struct wf_sat_sensor {
    struct list_head    link;
    int         index;
    int         index2;     /* used for power sensors */
    int         shift;
    struct wf_sat       *sat;
    struct wf_sensor    sens;
};

#define wf_to_sat(c)    container_of(c, struct wf_sat_sensor, sens)

struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
                          unsigned int *size)
{
    struct wf_sat *sat;
    int err;
    unsigned int i, len;
    u8 *buf;
    u8 data[4];

    /* TODO: Add the resulting partition to the device-tree */

    if (sat_id > 1 || (sat = sats[sat_id]) == NULL)
        return NULL;

    err = i2c_smbus_write_word_data(sat->i2c, 8, id << 8);
    if (err) {
        printk(KERN_ERR "smu_sat_get_sdb_part wr error %d\n", err);
        return NULL;
    }

    err = i2c_smbus_read_word_data(sat->i2c, 9);
    if (err < 0) {
        printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");
        return NULL;
    }
    len = err;
    if (len == 0) {
        printk(KERN_ERR "smu_sat_get_sdb_part no partition %x\n", id);
        return NULL;
    }

    len = le16_to_cpu(len);
    len = (len + 3) & ~3;
    buf = kmalloc(len, GFP_KERNEL);
    if (buf == NULL)
        return NULL;

    for (i = 0; i < len; i += 4) {
        err = i2c_smbus_read_i2c_block_data(sat->i2c, 0xa, 4, data);
        if (err < 0) {
            printk(KERN_ERR "smu_sat_get_sdb_part rd err %d\n",
                   err);
            goto fail;
        }
        buf[i] = data[1];
        buf[i+1] = data[0];
        buf[i+2] = data[3];
        buf[i+3] = data[2];
    }
#ifdef DEBUG
    DBG(KERN_DEBUG "sat %d partition %x:", sat_id, id);
    for (i = 0; i < len; ++i)
        DBG(" %x", buf[i]);
    DBG("\n");
#endif

    if (size)
        *size = len;
    return (struct smu_sdbp_header *) buf;

 fail:
    kfree(buf);
    return NULL;
}
EXPORT_SYMBOL_GPL(smu_sat_get_sdb_partition);

/* refresh the cache */
static int wf_sat_read_cache(struct wf_sat *sat)
{
    int err;

    err = i2c_smbus_read_i2c_block_data(sat->i2c, 0x3f, 16, sat->cache);
    if (err < 0)
        return err;
    sat->last_read = jiffies;
#ifdef LOTSA_DEBUG
    {
        int i;
        DBG(KERN_DEBUG "wf_sat_get: data is");
        for (i = 0; i < 16; ++i)
            DBG(" %.2x", sat->cache[i]);
        DBG("\n");
    }
#endif
    return 0;
}

static int wf_sat_sensor_get(struct wf_sensor *sr, s32 *value)
{
    struct wf_sat_sensor *sens = wf_to_sat(sr);
    struct wf_sat *sat = sens->sat;
    int i, err;
    s32 val;

    if (sat->i2c == NULL)
        return -ENODEV;

    mutex_lock(&sat->mutex);
    if (time_after(jiffies, (sat->last_read + MAX_AGE))) {
        err = wf_sat_read_cache(sat);
        if (err)
            goto fail;
    }

    i = sens->index * 2;
    val = ((sat->cache[i] << 8) + sat->cache[i+1]) << sens->shift;
    if (sens->index2 >= 0) {
        i = sens->index2 * 2;
        /* 4.12 * 8.8 -> 12.20; shift right 4 to get 16.16 */
        val = (val * ((sat->cache[i] << 8) + sat->cache[i+1])) >> 4;
    }

    *value = val;
    err = 0;

 fail:
    mutex_unlock(&sat->mutex);
    return err;
}

static void wf_sat_release(struct kref *ref)
{
    struct wf_sat *sat = container_of(ref, struct wf_sat, ref);

    if (sat->nr >= 0)
        sats[sat->nr] = NULL;
    kfree(sat);
}

static void wf_sat_sensor_release(struct wf_sensor *sr)
{
    struct wf_sat_sensor *sens = wf_to_sat(sr);
    struct wf_sat *sat = sens->sat;

    kfree(sens);
    kref_put(&sat->ref, wf_sat_release);
}

static struct wf_sensor_ops wf_sat_ops = {
    .get_value  = wf_sat_sensor_get,
    .release    = wf_sat_sensor_release,
    .owner      = THIS_MODULE,
};

static int wf_sat_probe(struct i2c_client *client,
            const struct i2c_device_id *id)
{
    struct device_node *dev = client->dev.of_node;
    struct wf_sat *sat;
    struct wf_sat_sensor *sens;
    const u32 *reg;
    const char *loc, *type;
    u8 chip, core;
    struct device_node *child;
    int shift, cpu, index;
    char *name;
    int vsens[2], isens[2];

    sat = kzalloc(sizeof(struct wf_sat), GFP_KERNEL);
    if (sat == NULL)
        return -ENOMEM;
    sat->nr = -1;
    sat->node = of_node_get(dev);
    kref_init(&sat->ref);
    mutex_init(&sat->mutex);
    sat->i2c = client;
    INIT_LIST_HEAD(&sat->sensors);
    i2c_set_clientdata(client, sat);

    vsens[0] = vsens[1] = -1;
    isens[0] = isens[1] = -1;
    child = NULL;
    while ((child = of_get_next_child(dev, child)) != NULL) {
        reg = of_get_property(child, "reg", NULL);
        type = of_get_property(child, "device_type", NULL);
        loc = of_get_property(child, "location", NULL);
        if (reg == NULL || loc == NULL)
            continue;

        /* the cooked sensors are between 0x30 and 0x37 */
        if (*reg < 0x30 || *reg > 0x37)
            continue;
        index = *reg - 0x30;

        /* expect location to be CPU [AB][01] ... */
        if (strncmp(loc, "CPU ", 4) != 0)
            continue;
        chip = loc[4] - 'A';
        core = loc[5] - '0';
        if (chip > 1 || core > 1) {
            printk(KERN_ERR "wf_sat_create: don't understand "
                   "location %s for %s\n", loc, child->full_name);
            continue;
        }
        cpu = 2 * chip + core;
        if (sat->nr < 0)
            sat->nr = chip;
        else if (sat->nr != chip) {
            printk(KERN_ERR "wf_sat_create: can't cope with "
                   "multiple CPU chips on one SAT (%s)\n", loc);
            continue;
        }

        if (strcmp(type, "voltage-sensor") == 0) {
            name = "cpu-voltage";
            shift = 4;
            vsens[core] = index;
        } else if (strcmp(type, "current-sensor") == 0) {
            name = "cpu-current";
            shift = 8;
            isens[core] = index;
        } else if (strcmp(type, "temp-sensor") == 0) {
            name = "cpu-temp";
            shift = 10;
        } else
            continue;   /* hmmm shouldn't happen */

        /* the +16 is enough for "cpu-voltage-n" */
        sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
        if (sens == NULL) {
            printk(KERN_ERR "wf_sat_create: couldn't create "
                   "%s sensor %d (no memory)\n", name, cpu);
            continue;
        }
        sens->index = index;
        sens->index2 = -1;
        sens->shift = shift;
        sens->sat = sat;
        sens->sens.ops = &wf_sat_ops;
        sens->sens.name = (char *) (sens + 1);
        snprintf((char *)sens->sens.name, 16, "%s-%d", name, cpu);

        if (wf_register_sensor(&sens->sens))
            kfree(sens);
        else {
            list_add(&sens->link, &sat->sensors);
            kref_get(&sat->ref);
        }
    }

    /* make the power sensors */
    for (core = 0; core < 2; ++core) {
        if (vsens[core] < 0 || isens[core] < 0)
            continue;
        cpu = 2 * sat->nr + core;
        sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
        if (sens == NULL) {
            printk(KERN_ERR "wf_sat_create: couldn't create power "
                   "sensor %d (no memory)\n", cpu);
            continue;
        }
        sens->index = vsens[core];
        sens->index2 = isens[core];
        sens->shift = 0;
        sens->sat = sat;
        sens->sens.ops = &wf_sat_ops;
        sens->sens.name = (char *) (sens + 1);
        snprintf((char *)sens->sens.name, 16, "cpu-power-%d", cpu);

        if (wf_register_sensor(&sens->sens))
            kfree(sens);
        else {
            list_add(&sens->link, &sat->sensors);
            kref_get(&sat->ref);
        }
    }

    if (sat->nr >= 0)
        sats[sat->nr] = sat;

    return 0;
}

static int wf_sat_remove(struct i2c_client *client)
{
    struct wf_sat *sat = i2c_get_clientdata(client);
    struct wf_sat_sensor *sens;

    /* release sensors */
    while(!list_empty(&sat->sensors)) {
        sens = list_first_entry(&sat->sensors,
                    struct wf_sat_sensor, link);
        list_del(&sens->link);
        wf_unregister_sensor(&sens->sens);
    }
    sat->i2c = NULL;
    i2c_set_clientdata(client, NULL);
    kref_put(&sat->ref, wf_sat_release);

    return 0;
}

static const struct i2c_device_id wf_sat_id[] = {
    { "MAC,smu-sat", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, wf_sat_id);

static struct i2c_driver wf_sat_driver = {
    .driver = {
        .name       = "wf_smu_sat",
    },
    .probe      = wf_sat_probe,
    .remove     = wf_sat_remove,
    .id_table   = wf_sat_id,
};

static int __init sat_sensors_init(void)
{
    return i2c_add_driver(&wf_sat_driver);
}

static void __exit sat_sensors_exit(void)
{
    i2c_del_driver(&wf_sat_driver);
}

module_init(sat_sensors_init);
module_exit(sat_sensors_exit);

MODULE_AUTHOR("Paul Mackerras <[email protected]>");
MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");
MODULE_LICENSE("GPL");