/*
   * 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 !
  ",
  		       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
  ",
  		       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
  ",
  		       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
  ",
  		       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
  ",
  		       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
  ",
  			    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
  ",
  			    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
  ",
  			    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
  ",
  			    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 !
  ");
  		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 ((of_machine_is_compatible("PowerMac8,1") ||
  	     of_machine_is_compatible("PowerMac8,2") ||
  	     of_machine_is_compatible("PowerMac9,1")) &&

  	    cpuvcp_version >= 2) {
  		pow->quadratic = 1;
  		DBG("windfarm: CPU Power using quadratic transform
  ");
  	} 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");