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windfarm_smu_sat.c

/*
 * 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");

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