/*
   * 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 <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
  ", 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
  ");
  		return NULL;
  	}

  	len = err;

  	if (len == 0) {
  		printk(KERN_ERR "smu_sat_get_sdb_part no partition %x
  ", 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
  ",
  			       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("
  ");
  #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("
  ");
  	}
  #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
  ", 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)
  ", 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)
  ", 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)
  ", 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;

  	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,
  };

  module_i2c_driver(wf_sat_driver);

  
  MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
  MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");
  MODULE_LICENSE("GPL");