/*
   * A hwmon driver for the IBM PowerExecutive temperature/power sensors
   * Copyright (C) 2007 IBM
   *
   * Author: Darrick J. Wong <darrick.wong@oracle.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  #include <linux/ipmi.h>
  #include <linux/module.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/jiffies.h>
  #include <linux/mutex.h>
  #include <linux/slab.h>
  #include <linux/err.h>
  
  #define REFRESH_INTERVAL	(2 * HZ)
  #define DRVNAME			"ibmpex"
  
  #define PEX_GET_VERSION		1
  #define PEX_GET_SENSOR_COUNT	2
  #define PEX_GET_SENSOR_NAME	3
  #define PEX_RESET_HIGH_LOW	4
  #define PEX_GET_SENSOR_DATA	6
  
  #define PEX_NET_FUNCTION	0x3A
  #define PEX_COMMAND		0x3C
  
  static inline u16 extract_value(const char *data, int offset)
  {
  	return be16_to_cpup((__be16 *)&data[offset]);
  }
  
  #define TEMP_SENSOR		1
  #define POWER_SENSOR		2
  
  #define PEX_SENSOR_TYPE_LEN	3
  static u8 const power_sensor_sig[] = {0x70, 0x77, 0x72};
  static u8 const temp_sensor_sig[]  = {0x74, 0x65, 0x6D};
  
  #define PEX_MULT_LEN		2
  static u8 const watt_sensor_sig[]  = {0x41, 0x43};
  
  #define PEX_NUM_SENSOR_FUNCS	3
  static char const * const power_sensor_name_templates[] = {
  	"%s%d_average",
  	"%s%d_average_lowest",
  	"%s%d_average_highest"
  };
  static char const * const temp_sensor_name_templates[] = {
  	"%s%d_input",
  	"%s%d_input_lowest",
  	"%s%d_input_highest"
  };
  
  static void ibmpex_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
  static void ibmpex_register_bmc(int iface, struct device *dev);
  static void ibmpex_bmc_gone(int iface);
  
  struct ibmpex_sensor_data {
  	int			in_use;
  	s16			values[PEX_NUM_SENSOR_FUNCS];
  	int			multiplier;
  
  	struct sensor_device_attribute_2	attr[PEX_NUM_SENSOR_FUNCS];
  };
  
  struct ibmpex_bmc_data {
  	struct list_head	list;
  	struct device		*hwmon_dev;
  	struct device		*bmc_device;
  	struct mutex		lock;
  	char			valid;
  	unsigned long		last_updated;	/* In jiffies */
  
  	struct ipmi_addr	address;
  	struct completion	read_complete;
  	ipmi_user_t		user;
  	int			interface;
  
  	struct kernel_ipmi_msg	tx_message;
  	unsigned char		tx_msg_data[IPMI_MAX_MSG_LENGTH];
  	long			tx_msgid;
  
  	unsigned char		rx_msg_data[IPMI_MAX_MSG_LENGTH];
  	unsigned long		rx_msg_len;
  	unsigned char		rx_result;
  	int			rx_recv_type;
  
  	unsigned char		sensor_major;
  	unsigned char		sensor_minor;
  
  	unsigned char		num_sensors;
  	struct ibmpex_sensor_data	*sensors;
  };
  
  struct ibmpex_driver_data {
  	struct list_head	bmc_data;
  	struct ipmi_smi_watcher	bmc_events;
  	struct ipmi_user_hndl	ipmi_hndlrs;
  };
  
  static struct ibmpex_driver_data driver_data = {
  	.bmc_data = LIST_HEAD_INIT(driver_data.bmc_data),
  	.bmc_events = {
  		.owner = THIS_MODULE,
  		.new_smi = ibmpex_register_bmc,
  		.smi_gone = ibmpex_bmc_gone,
  	},
  	.ipmi_hndlrs = {
  		.ipmi_recv_hndl = ibmpex_msg_handler,
  	},
  };
  
  static int ibmpex_send_message(struct ibmpex_bmc_data *data)
  {
  	int err;
  
  	err = ipmi_validate_addr(&data->address, sizeof(data->address));
  	if (err)
  		goto out;
  
  	data->tx_msgid++;
  	err = ipmi_request_settime(data->user, &data->address, data->tx_msgid,
  				   &data->tx_message, data, 0, 0, 0);
  	if (err)
  		goto out1;
  
  	return 0;
  out1:
  	dev_err(data->bmc_device, "request_settime=%x
  ", err);
  	return err;
  out:
  	dev_err(data->bmc_device, "validate_addr=%x
  ", err);
  	return err;
  }
  
  static int ibmpex_ver_check(struct ibmpex_bmc_data *data)
  {
  	data->tx_msg_data[0] = PEX_GET_VERSION;
  	data->tx_message.data_len = 1;
  	ibmpex_send_message(data);
  
  	wait_for_completion(&data->read_complete);
  
  	if (data->rx_result || data->rx_msg_len != 6)
  		return -ENOENT;
  
  	data->sensor_major = data->rx_msg_data[0];
  	data->sensor_minor = data->rx_msg_data[1];
  
  	dev_info(data->bmc_device,
  		 "Found BMC with sensor interface v%d.%d %d-%02d-%02d on interface %d
  ",
  		 data->sensor_major,
  		 data->sensor_minor,
  		 extract_value(data->rx_msg_data, 2),
  		 data->rx_msg_data[4],
  		 data->rx_msg_data[5],
  		 data->interface);
  
  	return 0;
  }
  
  static int ibmpex_query_sensor_count(struct ibmpex_bmc_data *data)
  {
  	data->tx_msg_data[0] = PEX_GET_SENSOR_COUNT;
  	data->tx_message.data_len = 1;
  	ibmpex_send_message(data);
  
  	wait_for_completion(&data->read_complete);
  
  	if (data->rx_result || data->rx_msg_len != 1)
  		return -ENOENT;
  
  	return data->rx_msg_data[0];
  }
  
  static int ibmpex_query_sensor_name(struct ibmpex_bmc_data *data, int sensor)
  {
  	data->tx_msg_data[0] = PEX_GET_SENSOR_NAME;
  	data->tx_msg_data[1] = sensor;
  	data->tx_message.data_len = 2;
  	ibmpex_send_message(data);
  
  	wait_for_completion(&data->read_complete);
  
  	if (data->rx_result || data->rx_msg_len < 1)
  		return -ENOENT;
  
  	return 0;
  }
  
  static int ibmpex_query_sensor_data(struct ibmpex_bmc_data *data, int sensor)
  {
  	data->tx_msg_data[0] = PEX_GET_SENSOR_DATA;
  	data->tx_msg_data[1] = sensor;
  	data->tx_message.data_len = 2;
  	ibmpex_send_message(data);
  
  	wait_for_completion(&data->read_complete);
  
  	if (data->rx_result || data->rx_msg_len < 26) {
  		dev_err(data->bmc_device, "Error reading sensor %d.
  ",
  			sensor);
  		return -ENOENT;
  	}
  
  	return 0;
  }
  
  static int ibmpex_reset_high_low_data(struct ibmpex_bmc_data *data)
  {
  	data->tx_msg_data[0] = PEX_RESET_HIGH_LOW;
  	data->tx_message.data_len = 1;
  	ibmpex_send_message(data);
  
  	wait_for_completion(&data->read_complete);
  
  	return 0;
  }
  
  static void ibmpex_update_device(struct ibmpex_bmc_data *data)
  {
  	int i, err;
  
  	mutex_lock(&data->lock);
  	if (time_before(jiffies, data->last_updated + REFRESH_INTERVAL) &&
  	    data->valid)
  		goto out;
  
  	for (i = 0; i < data->num_sensors; i++) {
  		if (!data->sensors[i].in_use)
  			continue;
  		err = ibmpex_query_sensor_data(data, i);
  		if (err)
  			continue;
  		data->sensors[i].values[0] =
  			extract_value(data->rx_msg_data, 16);
  		data->sensors[i].values[1] =
  			extract_value(data->rx_msg_data, 18);
  		data->sensors[i].values[2] =
  			extract_value(data->rx_msg_data, 20);
  	}
  
  	data->last_updated = jiffies;
  	data->valid = 1;
  
  out:
  	mutex_unlock(&data->lock);
  }
  
  static struct ibmpex_bmc_data *get_bmc_data(int iface)
  {
  	struct ibmpex_bmc_data *p, *next;
  
  	list_for_each_entry_safe(p, next, &driver_data.bmc_data, list)
  		if (p->interface == iface)
  			return p;
  
  	return NULL;
  }
  
  static ssize_t show_name(struct device *dev, struct device_attribute *devattr,
  			 char *buf)
  {
  	return sprintf(buf, "%s
  ", DRVNAME);
  }
  static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, 0);
  
  static ssize_t ibmpex_show_sensor(struct device *dev,
  				  struct device_attribute *devattr,
  				  char *buf)
  {
  	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
  	struct ibmpex_bmc_data *data = dev_get_drvdata(dev);
  	int mult = data->sensors[attr->index].multiplier;
  	ibmpex_update_device(data);
  
  	return sprintf(buf, "%d
  ",
  		       data->sensors[attr->index].values[attr->nr] * mult);
  }
  
  static ssize_t ibmpex_reset_high_low(struct device *dev,
  				     struct device_attribute *devattr,
  				     const char *buf,
  				     size_t count)
  {
  	struct ibmpex_bmc_data *data = dev_get_drvdata(dev);
  
  	ibmpex_reset_high_low_data(data);
  
  	return count;
  }
  
  static SENSOR_DEVICE_ATTR(reset_high_low, S_IWUSR, NULL,
  			  ibmpex_reset_high_low, 0);
  
  static int is_power_sensor(const char *sensor_id, int len)
  {
  	if (len < PEX_SENSOR_TYPE_LEN)
  		return 0;
  
  	if (!memcmp(sensor_id, power_sensor_sig, PEX_SENSOR_TYPE_LEN))
  		return 1;
  	return 0;
  }
  
  static int is_temp_sensor(const char *sensor_id, int len)
  {
  	if (len < PEX_SENSOR_TYPE_LEN)
  		return 0;
  
  	if (!memcmp(sensor_id, temp_sensor_sig, PEX_SENSOR_TYPE_LEN))
  		return 1;
  	return 0;
  }
  
  static int power_sensor_multiplier(struct ibmpex_bmc_data *data,
  				   const char *sensor_id, int len)
  {
  	int i;
  
  	if (data->sensor_major == 2)
  		return 1000000;
  
  	for (i = PEX_SENSOR_TYPE_LEN; i < len - 1; i++)
  		if (!memcmp(&sensor_id[i], watt_sensor_sig, PEX_MULT_LEN))
  			return 1000000;
  
  	return 100000;
  }
  
  static int create_sensor(struct ibmpex_bmc_data *data, int type,
  			 int counter, int sensor, int func)
  {
  	int err;
  	char *n;
  
  	n = kmalloc(32, GFP_KERNEL);
  	if (!n)
  		return -ENOMEM;
  
  	if (type == TEMP_SENSOR)
  		sprintf(n, temp_sensor_name_templates[func], "temp", counter);
  	else if (type == POWER_SENSOR)
  		sprintf(n, power_sensor_name_templates[func], "power", counter);
  
  	sysfs_attr_init(&data->sensors[sensor].attr[func].dev_attr.attr);
  	data->sensors[sensor].attr[func].dev_attr.attr.name = n;
  	data->sensors[sensor].attr[func].dev_attr.attr.mode = S_IRUGO;
  	data->sensors[sensor].attr[func].dev_attr.show = ibmpex_show_sensor;
  	data->sensors[sensor].attr[func].index = sensor;
  	data->sensors[sensor].attr[func].nr = func;
  
  	err = device_create_file(data->bmc_device,
  				 &data->sensors[sensor].attr[func].dev_attr);
  	if (err) {
  		data->sensors[sensor].attr[func].dev_attr.attr.name = NULL;
  		kfree(n);
  		return err;
  	}
  
  	return 0;
  }
  
  static int ibmpex_find_sensors(struct ibmpex_bmc_data *data)
  {
  	int i, j, err;
  	int sensor_type;
  	int sensor_counter;
  	int num_power = 0;
  	int num_temp = 0;
  
  	err = ibmpex_query_sensor_count(data);
  	if (err <= 0)
  		return -ENOENT;
  	data->num_sensors = err;
  
  	data->sensors = kzalloc(data->num_sensors * sizeof(*data->sensors),
  				GFP_KERNEL);
  	if (!data->sensors)
  		return -ENOMEM;
  
  	for (i = 0; i < data->num_sensors; i++) {
  		err = ibmpex_query_sensor_name(data, i);
  		if (err)
  			continue;
  
  		if (is_power_sensor(data->rx_msg_data, data->rx_msg_len)) {
  			sensor_type = POWER_SENSOR;
  			num_power++;
  			sensor_counter = num_power;
  			data->sensors[i].multiplier =
  				power_sensor_multiplier(data,
  							data->rx_msg_data,
  							data->rx_msg_len);
  		} else if (is_temp_sensor(data->rx_msg_data,
  					  data->rx_msg_len)) {
  			sensor_type = TEMP_SENSOR;
  			num_temp++;
  			sensor_counter = num_temp;
  			data->sensors[i].multiplier = 1000;
  		} else
  			continue;
  
  		data->sensors[i].in_use = 1;
  
  		/* Create attributes */
  		for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
  			err = create_sensor(data, sensor_type, sensor_counter,
  					    i, j);
  			if (err)
  				goto exit_remove;
  		}
  	}
  
  	err = device_create_file(data->bmc_device,
  			&sensor_dev_attr_reset_high_low.dev_attr);
  	if (err)
  		goto exit_remove;
  
  	err = device_create_file(data->bmc_device,
  			&sensor_dev_attr_name.dev_attr);
  	if (err)
  		goto exit_remove;
  
  	return 0;
  
  exit_remove:
  	device_remove_file(data->bmc_device,
  			   &sensor_dev_attr_reset_high_low.dev_attr);
  	device_remove_file(data->bmc_device, &sensor_dev_attr_name.dev_attr);
  	for (i = 0; i < data->num_sensors; i++)
  		for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
  			if (!data->sensors[i].attr[j].dev_attr.attr.name)
  				continue;
  			device_remove_file(data->bmc_device,
  				&data->sensors[i].attr[j].dev_attr);
  			kfree(data->sensors[i].attr[j].dev_attr.attr.name);
  		}
  
  	kfree(data->sensors);
  	return err;
  }
  
  static void ibmpex_register_bmc(int iface, struct device *dev)
  {
  	struct ibmpex_bmc_data *data;
  	int err;
  
  	data = kzalloc(sizeof(*data), GFP_KERNEL);
  	if (!data) {
  		dev_err(dev, "Insufficient memory for BMC interface.
  ");
  		return;
  	}
  
  	data->address.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  	data->address.channel = IPMI_BMC_CHANNEL;
  	data->address.data[0] = 0;
  	data->interface = iface;
  	data->bmc_device = dev;
  
  	/* Create IPMI messaging interface user */
  	err = ipmi_create_user(data->interface, &driver_data.ipmi_hndlrs,
  			       data, &data->user);
  	if (err < 0) {
  		dev_err(dev,
  			"Unable to register user with IPMI interface %d
  ",
  			data->interface);
  		goto out;
  	}
  
  	mutex_init(&data->lock);
  
  	/* Initialize message */
  	data->tx_msgid = 0;
  	init_completion(&data->read_complete);
  	data->tx_message.netfn = PEX_NET_FUNCTION;
  	data->tx_message.cmd = PEX_COMMAND;
  	data->tx_message.data = data->tx_msg_data;
  
  	/* Does this BMC support PowerExecutive? */
  	err = ibmpex_ver_check(data);
  	if (err)
  		goto out_user;
  
  	/* Register the BMC as a HWMON class device */
  	data->hwmon_dev = hwmon_device_register(data->bmc_device);
  
  	if (IS_ERR(data->hwmon_dev)) {
  		dev_err(data->bmc_device,
  			"Unable to register hwmon device for IPMI interface %d
  ",
  			data->interface);
  		goto out_user;
  	}
  
  	/* finally add the new bmc data to the bmc data list */
  	dev_set_drvdata(dev, data);
  	list_add_tail(&data->list, &driver_data.bmc_data);
  
  	/* Now go find all the sensors */
  	err = ibmpex_find_sensors(data);
  	if (err) {
  		dev_err(data->bmc_device, "Error %d finding sensors
  ", err);
  		goto out_register;
  	}
  
  	return;
  
  out_register:
  	hwmon_device_unregister(data->hwmon_dev);
  out_user:
  	ipmi_destroy_user(data->user);
  out:
  	kfree(data);
  }
  
  static void ibmpex_bmc_delete(struct ibmpex_bmc_data *data)
  {
  	int i, j;
  
  	device_remove_file(data->bmc_device,
  			   &sensor_dev_attr_reset_high_low.dev_attr);
  	device_remove_file(data->bmc_device, &sensor_dev_attr_name.dev_attr);
  	for (i = 0; i < data->num_sensors; i++)
  		for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
  			if (!data->sensors[i].attr[j].dev_attr.attr.name)
  				continue;
  			device_remove_file(data->bmc_device,
  				&data->sensors[i].attr[j].dev_attr);
  			kfree(data->sensors[i].attr[j].dev_attr.attr.name);
  		}
  
  	list_del(&data->list);
  	dev_set_drvdata(data->bmc_device, NULL);
  	hwmon_device_unregister(data->hwmon_dev);
  	ipmi_destroy_user(data->user);
  	kfree(data->sensors);
  	kfree(data);
  }
  
  static void ibmpex_bmc_gone(int iface)
  {
  	struct ibmpex_bmc_data *data = get_bmc_data(iface);
  
  	if (!data)
  		return;
  
  	ibmpex_bmc_delete(data);
  }
  
  static void ibmpex_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
  {
  	struct ibmpex_bmc_data *data = (struct ibmpex_bmc_data *)user_msg_data;
  
  	if (msg->msgid != data->tx_msgid) {
  		dev_err(data->bmc_device,
  			"Mismatch between received msgid (%02x) and transmitted msgid (%02x)!
  ",
  			(int)msg->msgid,
  			(int)data->tx_msgid);
  		ipmi_free_recv_msg(msg);
  		return;
  	}
  
  	data->rx_recv_type = msg->recv_type;
  	if (msg->msg.data_len > 0)
  		data->rx_result = msg->msg.data[0];
  	else
  		data->rx_result = IPMI_UNKNOWN_ERR_COMPLETION_CODE;
  
  	if (msg->msg.data_len > 1) {
  		data->rx_msg_len = msg->msg.data_len - 1;
  		memcpy(data->rx_msg_data, msg->msg.data + 1, data->rx_msg_len);
  	} else
  		data->rx_msg_len = 0;
  
  	ipmi_free_recv_msg(msg);
  	complete(&data->read_complete);
  }
  
  static int __init ibmpex_init(void)
  {
  	return ipmi_smi_watcher_register(&driver_data.bmc_events);
  }
  
  static void __exit ibmpex_exit(void)
  {
  	struct ibmpex_bmc_data *p, *next;
  
  	ipmi_smi_watcher_unregister(&driver_data.bmc_events);
  	list_for_each_entry_safe(p, next, &driver_data.bmc_data, list)
  		ibmpex_bmc_delete(p);
  }
  
  MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
  MODULE_DESCRIPTION("IBM PowerExecutive power/temperature sensor driver");
  MODULE_LICENSE("GPL");
  
  module_init(ibmpex_init);
  module_exit(ibmpex_exit);
  
  MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3350-*");
  MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3550-*");
  MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3650-*");
  MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3655-*");
  MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3755-*");