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windfarm_smu_sensors.c

/*
 * Windfarm PowerMac thermal control. SMU based sensors
 *
 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 *                    <benh@kernel.crashing.org>
 *
 * Released under the term of the GNU GPL v2.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/completion.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/sections.h>
#include <asm/smu.h>

#include "windfarm.h"

#define VERSION "0.2"

#undef DEBUG

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

/*
 * Various SMU "partitions" calibration objects for which we
 * keep pointers here for use by bits & pieces of the driver
 */
static struct smu_sdbp_cpuvcp *cpuvcp;
static int  cpuvcp_version;
static struct smu_sdbp_cpudiode *cpudiode;
static struct smu_sdbp_slotspow *slotspow;
static u8 *debugswitches;

/*
 * SMU basic sensors objects
 */

static LIST_HEAD(smu_ads);

struct smu_ad_sensor {
      struct list_head  link;
      u32               reg;        /* index in SMU */
      struct wf_sensor  sens;
};
#define to_smu_ads(c) container_of(c, struct smu_ad_sensor, sens)

static void smu_ads_release(struct wf_sensor *sr)
{
      struct smu_ad_sensor *ads = to_smu_ads(sr);

      kfree(ads);
}

static int smu_read_adc(u8 id, s32 *value)
{
      struct smu_simple_cmd   cmd;
      DECLARE_COMPLETION_ONSTACK(comp);
      int rc;

      rc = smu_queue_simple(&cmd, SMU_CMD_READ_ADC, 1,
                        smu_done_complete, &comp, id);
      if (rc)
            return rc;
      wait_for_completion(&comp);
      if (cmd.cmd.status != 0)
            return cmd.cmd.status;
      if (cmd.cmd.reply_len != 2) {
            printk(KERN_ERR "winfarm: read ADC 0x%x returned %d bytes !\n",
                   id, cmd.cmd.reply_len);
            return -EIO;
      }
      *value = *((u16 *)cmd.buffer);
      return 0;
}

static int smu_cputemp_get(struct wf_sensor *sr, s32 *value)
{
      struct smu_ad_sensor *ads = to_smu_ads(sr);
      int rc;
      s32 val;
      s64 scaled;

      rc = smu_read_adc(ads->reg, &val);
      if (rc) {
            printk(KERN_ERR "windfarm: read CPU temp failed, err %d\n",
                   rc);
            return rc;
      }

      /* Ok, we have to scale & adjust, taking units into account */
      scaled = (s64)(((u64)val) * (u64)cpudiode->m_value);
      scaled >>= 3;
      scaled += ((s64)cpudiode->b_value) << 9;
      *value = (s32)(scaled << 1);

      return 0;
}

static int smu_cpuamp_get(struct wf_sensor *sr, s32 *value)
{
      struct smu_ad_sensor *ads = to_smu_ads(sr);
      s32 val, scaled;
      int rc;

      rc = smu_read_adc(ads->reg, &val);
      if (rc) {
            printk(KERN_ERR "windfarm: read CPU current failed, err %d\n",
                   rc);
            return rc;
      }

      /* Ok, we have to scale & adjust, taking units into account */
      scaled = (s32)(val * (u32)cpuvcp->curr_scale);
      scaled += (s32)cpuvcp->curr_offset;
      *value = scaled << 4;

      return 0;
}

static int smu_cpuvolt_get(struct wf_sensor *sr, s32 *value)
{
      struct smu_ad_sensor *ads = to_smu_ads(sr);
      s32 val, scaled;
      int rc;

      rc = smu_read_adc(ads->reg, &val);
      if (rc) {
            printk(KERN_ERR "windfarm: read CPU voltage failed, err %d\n",
                   rc);
            return rc;
      }

      /* Ok, we have to scale & adjust, taking units into account */
      scaled = (s32)(val * (u32)cpuvcp->volt_scale);
      scaled += (s32)cpuvcp->volt_offset;
      *value = scaled << 4;

      return 0;
}

static int smu_slotspow_get(struct wf_sensor *sr, s32 *value)
{
      struct smu_ad_sensor *ads = to_smu_ads(sr);
      s32 val, scaled;
      int rc;

      rc = smu_read_adc(ads->reg, &val);
      if (rc) {
            printk(KERN_ERR "windfarm: read slots power failed, err %d\n",
                   rc);
            return rc;
      }

      /* Ok, we have to scale & adjust, taking units into account */
      scaled = (s32)(val * (u32)slotspow->pow_scale);
      scaled += (s32)slotspow->pow_offset;
      *value = scaled << 4;

      return 0;
}


static struct wf_sensor_ops smu_cputemp_ops = {
      .get_value  = smu_cputemp_get,
      .release    = smu_ads_release,
      .owner            = THIS_MODULE,
};
static struct wf_sensor_ops smu_cpuamp_ops = {
      .get_value  = smu_cpuamp_get,
      .release    = smu_ads_release,
      .owner            = THIS_MODULE,
};
static struct wf_sensor_ops smu_cpuvolt_ops = {
      .get_value  = smu_cpuvolt_get,
      .release    = smu_ads_release,
      .owner            = THIS_MODULE,
};
static struct wf_sensor_ops smu_slotspow_ops = {
      .get_value  = smu_slotspow_get,
      .release    = smu_ads_release,
      .owner            = THIS_MODULE,
};


static struct smu_ad_sensor *smu_ads_create(struct device_node *node)
{
      struct smu_ad_sensor *ads;
      const char *c, *l;
      const u32 *v;

      ads = kmalloc(sizeof(struct smu_ad_sensor), GFP_KERNEL);
      if (ads == NULL)
            return NULL;
      c = of_get_property(node, "device_type", NULL);
      l = of_get_property(node, "location", NULL);
      if (c == NULL || l == NULL)
            goto fail;

      /* We currently pick the sensors based on the OF name and location
       * properties, while Darwin uses the sensor-id's.
       * The problem with the IDs is that they are model specific while it
       * looks like apple has been doing a reasonably good job at keeping
       * the names and locations consistents so I'll stick with the names
       * and locations for now.
       */
      if (!strcmp(c, "temp-sensor") &&
          !strcmp(l, "CPU T-Diode")) {
            ads->sens.ops = &smu_cputemp_ops;
            ads->sens.name = "cpu-temp";
            if (cpudiode == NULL) {
                  DBG("wf: cpudiode partition (%02x) not found\n",
                      SMU_SDB_CPUDIODE_ID);
                  goto fail;
            }
      } else if (!strcmp(c, "current-sensor") &&
               !strcmp(l, "CPU Current")) {
            ads->sens.ops = &smu_cpuamp_ops;
            ads->sens.name = "cpu-current";
            if (cpuvcp == NULL) {
                  DBG("wf: cpuvcp partition (%02x) not found\n",
                      SMU_SDB_CPUVCP_ID);
                  goto fail;
            }
      } else if (!strcmp(c, "voltage-sensor") &&
               !strcmp(l, "CPU Voltage")) {
            ads->sens.ops = &smu_cpuvolt_ops;
            ads->sens.name = "cpu-voltage";
            if (cpuvcp == NULL) {
                  DBG("wf: cpuvcp partition (%02x) not found\n",
                      SMU_SDB_CPUVCP_ID);
                  goto fail;
            }
      } else if (!strcmp(c, "power-sensor") &&
               !strcmp(l, "Slots Power")) {
            ads->sens.ops = &smu_slotspow_ops;
            ads->sens.name = "slots-power";
            if (slotspow == NULL) {
                  DBG("wf: slotspow partition (%02x) not found\n",
                      SMU_SDB_SLOTSPOW_ID);
                  goto fail;
            }
      } else
            goto fail;

      v = of_get_property(node, "reg", NULL);
      if (v == NULL)
            goto fail;
      ads->reg = *v;

      if (wf_register_sensor(&ads->sens))
            goto fail;
      return ads;
 fail:
      kfree(ads);
      return NULL;
}

/*
 * SMU Power combo sensor object
 */

struct smu_cpu_power_sensor {
      struct list_head  link;
      struct wf_sensor  *volts;
      struct wf_sensor  *amps;
      int               fake_volts : 1;
      int               quadratic : 1;
      struct wf_sensor  sens;
};
#define to_smu_cpu_power(c) container_of(c, struct smu_cpu_power_sensor, sens)

static struct smu_cpu_power_sensor *smu_cpu_power;

static void smu_cpu_power_release(struct wf_sensor *sr)
{
      struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);

      if (pow->volts)
            wf_put_sensor(pow->volts);
      if (pow->amps)
            wf_put_sensor(pow->amps);
      kfree(pow);
}

static int smu_cpu_power_get(struct wf_sensor *sr, s32 *value)
{
      struct smu_cpu_power_sensor *pow = to_smu_cpu_power(sr);
      s32 volts, amps, power;
      u64 tmps, tmpa, tmpb;
      int rc;

      rc = pow->amps->ops->get_value(pow->amps, &amps);
      if (rc)
            return rc;

      if (pow->fake_volts) {
            *value = amps * 12 - 0x30000;
            return 0;
      }

      rc = pow->volts->ops->get_value(pow->volts, &volts);
      if (rc)
            return rc;

      power = (s32)((((u64)volts) * ((u64)amps)) >> 16);
      if (!pow->quadratic) {
            *value = power;
            return 0;
      }
      tmps = (((u64)power) * ((u64)power)) >> 16;
      tmpa = ((u64)cpuvcp->power_quads[0]) * tmps;
      tmpb = ((u64)cpuvcp->power_quads[1]) * ((u64)power);
      *value = (tmpa >> 28) + (tmpb >> 28) + (cpuvcp->power_quads[2] >> 12);

      return 0;
}

static struct wf_sensor_ops smu_cpu_power_ops = {
      .get_value  = smu_cpu_power_get,
      .release    = smu_cpu_power_release,
      .owner            = THIS_MODULE,
};


static struct smu_cpu_power_sensor *
smu_cpu_power_create(struct wf_sensor *volts, struct wf_sensor *amps)
{
      struct smu_cpu_power_sensor *pow;

      pow = kmalloc(sizeof(struct smu_cpu_power_sensor), GFP_KERNEL);
      if (pow == NULL)
            return NULL;
      pow->sens.ops = &smu_cpu_power_ops;
      pow->sens.name = "cpu-power";

      wf_get_sensor(volts);
      pow->volts = volts;
      wf_get_sensor(amps);
      pow->amps = amps;

      /* Some early machines need a faked voltage */
      if (debugswitches && ((*debugswitches) & 0x80)) {
            printk(KERN_INFO "windfarm: CPU Power sensor using faked"
                   " voltage !\n");
            pow->fake_volts = 1;
      } else
            pow->fake_volts = 0;

      /* Try to use quadratic transforms on PowerMac8,1 and 9,1 for now,
       * I yet have to figure out what's up with 8,2 and will have to
       * adjust for later, unless we can 100% trust the SDB partition...
       */
      if ((machine_is_compatible("PowerMac8,1") ||
           machine_is_compatible("PowerMac8,2") ||
           machine_is_compatible("PowerMac9,1")) &&
          cpuvcp_version >= 2) {
            pow->quadratic = 1;
            DBG("windfarm: CPU Power using quadratic transform\n");
      } else
            pow->quadratic = 0;

      if (wf_register_sensor(&pow->sens))
            goto fail;
      return pow;
 fail:
      kfree(pow);
      return NULL;
}

static void smu_fetch_param_partitions(void)
{
      const struct smu_sdbp_header *hdr;

      /* Get CPU voltage/current/power calibration data */
      hdr = smu_get_sdb_partition(SMU_SDB_CPUVCP_ID, NULL);
      if (hdr != NULL) {
            cpuvcp = (struct smu_sdbp_cpuvcp *)&hdr[1];
            /* Keep version around */
            cpuvcp_version = hdr->version;
      }

      /* Get CPU diode calibration data */
      hdr = smu_get_sdb_partition(SMU_SDB_CPUDIODE_ID, NULL);
      if (hdr != NULL)
            cpudiode = (struct smu_sdbp_cpudiode *)&hdr[1];

      /* Get slots power calibration data if any */
      hdr = smu_get_sdb_partition(SMU_SDB_SLOTSPOW_ID, NULL);
      if (hdr != NULL)
            slotspow = (struct smu_sdbp_slotspow *)&hdr[1];

      /* Get debug switches if any */
      hdr = smu_get_sdb_partition(SMU_SDB_DEBUG_SWITCHES_ID, NULL);
      if (hdr != NULL)
            debugswitches = (u8 *)&hdr[1];
}

static int __init smu_sensors_init(void)
{
      struct device_node *smu, *sensors, *s;
      struct smu_ad_sensor *volt_sensor = NULL, *curr_sensor = NULL;

      if (!smu_present())
            return -ENODEV;

      /* Get parameters partitions */
      smu_fetch_param_partitions();

      smu = of_find_node_by_type(NULL, "smu");
      if (smu == NULL)
            return -ENODEV;

      /* Look for sensors subdir */
      for (sensors = NULL;
           (sensors = of_get_next_child(smu, sensors)) != NULL;)
            if (!strcmp(sensors->name, "sensors"))
                  break;

      of_node_put(smu);

      /* Create basic sensors */
      for (s = NULL;
           sensors && (s = of_get_next_child(sensors, s)) != NULL;) {
            struct smu_ad_sensor *ads;

            ads = smu_ads_create(s);
            if (ads == NULL)
                  continue;
            list_add(&ads->link, &smu_ads);
            /* keep track of cpu voltage & current */
            if (!strcmp(ads->sens.name, "cpu-voltage"))
                  volt_sensor = ads;
            else if (!strcmp(ads->sens.name, "cpu-current"))
                  curr_sensor = ads;
      }

      of_node_put(sensors);

      /* Create CPU power sensor if possible */
      if (volt_sensor && curr_sensor)
            smu_cpu_power = smu_cpu_power_create(&volt_sensor->sens,
                                         &curr_sensor->sens);

      return 0;
}

static void __exit smu_sensors_exit(void)
{
      struct smu_ad_sensor *ads;

      /* dispose of power sensor */
      if (smu_cpu_power)
            wf_unregister_sensor(&smu_cpu_power->sens);

      /* dispose of basic sensors */
      while (!list_empty(&smu_ads)) {
            ads = list_entry(smu_ads.next, struct smu_ad_sensor, link);
            list_del(&ads->link);
            wf_unregister_sensor(&ads->sens);
      }
}


module_init(smu_sensors_init);
module_exit(smu_sensors_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("SMU sensor objects for PowerMacs thermal control");
MODULE_LICENSE("GPL");


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