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/*

 * Windfarm PowerMac thermal control.  SMU "satellite" controller sensors.

 *

 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>

 *

 * 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 <asm/semaphore.h>

#include <asm/prom.h>

#include <asm/smu.h>

#include <asm/pmac_low_i2c.h>

#include "windfarm.h"

#define VERSION "0.2"

#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 {

        int                     nr;

        atomic_t                refcnt;

        struct semaphore        mutex;

        unsigned long           last_read; /* jiffies when cache last updated */

        u8                      cache[16];

        struct i2c_client       i2c;

        struct device_node      *node;

};

static struct wf_sat *sats[2];

struct wf_sat_sensor {

        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)

#define i2c_to_sat(c)   container_of(c, struct wf_sat, i2c)

static int wf_sat_attach(struct i2c_adapter *adapter);

static int wf_sat_detach(struct i2c_client *client);

static struct i2c_driver wf_sat_driver = {

        .driver = {

                .name           = "wf_smu_sat",

        },

        .attach_adapter = wf_sat_attach,

        .detach_client  = wf_sat_detach,

};

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;

        }

        len = i2c_smbus_read_word_data(&sat->i2c, 9);

        if (len < 0) {

                printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");

                return NULL;

        }

        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_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.adapter == NULL)

                return -ENODEV;

        down(&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:

        up(&sat->mutex);

        return err;

}

static void wf_sat_release(struct wf_sensor *sr)

{

        struct wf_sat_sensor *sens = wf_to_sat(sr);

        struct wf_sat *sat = sens->sat;

        if (atomic_dec_and_test(&sat->refcnt)) {

                if (sat->i2c.adapter) {

                        i2c_detach_client(&sat->i2c);

                        sat->i2c.adapter = NULL;

                }

                if (sat->nr >= 0)

                        sats[sat->nr] = NULL;

                kfree(sat);

        }

        kfree(sens);

}

static struct wf_sensor_ops wf_sat_ops = {

        .get_value      = wf_sat_get,

        .release        = wf_sat_release,

        .owner          = THIS_MODULE,

};

static void wf_sat_create(struct i2c_adapter *adapter, struct device_node *dev)

{

        struct wf_sat *sat;

        struct wf_sat_sensor *sens;

        const u32 *reg;

        const char *loc, *type;

        u8 addr, chip, core;

        struct device_node *child;

        int shift, cpu, index;

        char *name;

        int vsens[2], isens[2];

        reg = of_get_property(dev, "reg", NULL);

        if (reg == NULL)

                return;

        addr = *reg;

        DBG(KERN_DEBUG "wf_sat: creating sat at address %x\n", addr);

        sat = kzalloc(sizeof(struct wf_sat), GFP_KERNEL);

        if (sat == NULL)

                return;

        sat->nr = -1;

        sat->node = of_node_get(dev);

        atomic_set(&sat->refcnt, 0);

        init_MUTEX(&sat->mutex);

        sat->i2c.addr = (addr >> 1) & 0x7f;

        sat->i2c.adapter = adapter;

        sat->i2c.driver = &wf_sat_driver;

        strncpy(sat->i2c.name, "smu-sat", I2C_NAME_SIZE-1);

        if (i2c_attach_client(&sat->i2c)) {

                printk(KERN_ERR "windfarm: failed to attach smu-sat to i2c\n");

                goto fail;

        }

        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;

                atomic_inc(&sat->refcnt);

                sens->sens.ops = &wf_sat_ops;

                sens->sens.name = (char *) (sens + 1);

                snprintf(sens->sens.name, 16, "%s-%d", name, cpu);

                if (wf_register_sensor(&sens->sens)) {

                        atomic_dec(&sat->refcnt);

                        kfree(sens);

                }

        }

        /* 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;

                atomic_inc(&sat->refcnt);

                sens->sens.ops = &wf_sat_ops;

                sens->sens.name = (char *) (sens + 1);

                snprintf(sens->sens.name, 16, "cpu-power-%d", cpu);

                if (wf_register_sensor(&sens->sens)) {

                        atomic_dec(&sat->refcnt);

                        kfree(sens);

                }

        }

        if (sat->nr >= 0)

                sats[sat->nr] = sat;

        return;

 fail:

        kfree(sat);

}

static int wf_sat_attach(struct i2c_adapter *adapter)

{

        struct device_node *busnode, *dev = NULL;

        struct pmac_i2c_bus *bus;

        bus = pmac_i2c_adapter_to_bus(adapter);

        if (bus == NULL)

                return -ENODEV;

        busnode = pmac_i2c_get_bus_node(bus);

        while ((dev = of_get_next_child(busnode, dev)) != NULL)

                if (of_device_is_compatible(dev, "smu-sat"))

                        wf_sat_create(adapter, dev);

        return 0;

}

static int wf_sat_detach(struct i2c_client *client)

{

        struct wf_sat *sat = i2c_to_sat(client);

        /* XXX TODO */

        sat->i2c.adapter = NULL;

        return 0;

}

static int __init sat_sensors_init(void)

{

        return i2c_add_driver(&wf_sat_driver);

}

#if 0   /* uncomment when module_exit() below is uncommented */

static void __exit sat_sensors_exit(void)

{

        i2c_del_driver(&wf_sat_driver);

}

#endif

module_init(sat_sensors_init);

/*module_exit(sat_sensors_exit); Uncomment when cleanup is implemented */

MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");

MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");

MODULE_LICENSE("GPL");