/*
   * pkgtemp.c - Linux kernel module for processor package hardware monitoring
   *
   * Copyright (C) 2010 Fenghua Yu <fenghua.yu@intel.com>
   *
   * Inspired from many hwmon drivers especially coretemp.
   *
   * 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; version 2 of the License.
   *
   * 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., 51 Franklin Street, Fifth Floor, Boston, MA
   * 02110-1301 USA.
   */
  
  #include <linux/module.h>
  #include <linux/delay.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/hwmon.h>
  #include <linux/sysfs.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  #include <linux/list.h>
  #include <linux/platform_device.h>
  #include <linux/cpu.h>

  #include <asm/msr.h>
  #include <asm/processor.h>
  
  #define DRVNAME	"pkgtemp"
  
  enum { SHOW_TEMP, SHOW_TJMAX, SHOW_TTARGET, SHOW_LABEL, SHOW_NAME };
  
  /*
   * Functions declaration
   */
  
  static struct pkgtemp_data *pkgtemp_update_device(struct device *dev);
  
  struct pkgtemp_data {
  	struct device *hwmon_dev;
  	struct mutex update_lock;
  	const char *name;
  	u32 id;
  	u16 phys_proc_id;
  	char valid;		/* zero until following fields are valid */
  	unsigned long last_updated;	/* in jiffies */
  	int temp;
  	int tjmax;
  	int ttarget;
  	u8 alarm;
  };
  
  /*
   * Sysfs stuff
   */
  
  static ssize_t show_name(struct device *dev, struct device_attribute
  			  *devattr, char *buf)
  {
  	int ret;
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct pkgtemp_data *data = dev_get_drvdata(dev);
  
  	if (attr->index == SHOW_NAME)
  		ret = sprintf(buf, "%s
  ", data->name);
  	else	/* show label */
  		ret = sprintf(buf, "physical id %d
  ",
  			      data->phys_proc_id);
  	return ret;
  }
  
  static ssize_t show_alarm(struct device *dev, struct device_attribute
  			  *devattr, char *buf)
  {
  	struct pkgtemp_data *data = pkgtemp_update_device(dev);
  	/* read the Out-of-spec log, never clear */
  	return sprintf(buf, "%d
  ", data->alarm);
  }
  
  static ssize_t show_temp(struct device *dev,
  			 struct device_attribute *devattr, char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct pkgtemp_data *data = pkgtemp_update_device(dev);
  	int err = 0;
  
  	if (attr->index == SHOW_TEMP)
  		err = data->valid ? sprintf(buf, "%d
  ", data->temp) : -EAGAIN;
  	else if (attr->index == SHOW_TJMAX)
  		err = sprintf(buf, "%d
  ", data->tjmax);
  	else
  		err = sprintf(buf, "%d
  ", data->ttarget);
  	return err;
  }
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, SHOW_TEMP);
  static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_temp, NULL, SHOW_TJMAX);
  static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, SHOW_TTARGET);
  static DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL);
  static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_name, NULL, SHOW_LABEL);
  static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, SHOW_NAME);
  
  static struct attribute *pkgtemp_attributes[] = {
  	&sensor_dev_attr_name.dev_attr.attr,
  	&sensor_dev_attr_temp1_label.dev_attr.attr,
  	&dev_attr_temp1_crit_alarm.attr,
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group pkgtemp_group = {
  	.attrs = pkgtemp_attributes,
  };
  
  static struct pkgtemp_data *pkgtemp_update_device(struct device *dev)
  {
  	struct pkgtemp_data *data = dev_get_drvdata(dev);
  	unsigned int cpu;
  	int err;
  
  	mutex_lock(&data->update_lock);
  
  	if (!data->valid || time_after(jiffies, data->last_updated + HZ)) {
  		u32 eax, edx;
  
  		data->valid = 0;
  		cpu = data->id;
  		err = rdmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_STATUS,
  				   &eax, &edx);
  		if (!err) {
  			data->alarm = (eax >> 5) & 1;
  			data->temp = data->tjmax - (((eax >> 16)
  							& 0x7f) * 1000);
  			data->valid = 1;
  		} else
  			dev_dbg(dev, "Temperature data invalid (0x%x)
  ", eax);
  
  		data->last_updated = jiffies;
  	}
  
  	mutex_unlock(&data->update_lock);
  	return data;
  }
  
  static int get_tjmax(int cpu, struct device *dev)
  {
  	int default_tjmax = 100000;
  	int err;
  	u32 eax, edx;
  	u32 val;
  
  	/* IA32_TEMPERATURE_TARGET contains the TjMax value */
  	err = rdmsr_safe_on_cpu(cpu, MSR_IA32_TEMPERATURE_TARGET, &eax, &edx);
  	if (!err) {
  		val = (eax >> 16) & 0xff;
  		if ((val > 80) && (val < 120)) {
  			dev_info(dev, "TjMax is %d C.
  ", val);
  			return val * 1000;
  		}
  	}
  	dev_warn(dev, "Unable to read TjMax from CPU.
  ");
  	return default_tjmax;
  }
  
  static int __devinit pkgtemp_probe(struct platform_device *pdev)
  {
  	struct pkgtemp_data *data;
  	int err;
  	u32 eax, edx;
  #ifdef CONFIG_SMP
  	struct cpuinfo_x86 *c = &cpu_data(pdev->id);
  #endif
  
  	data = kzalloc(sizeof(struct pkgtemp_data), GFP_KERNEL);
  	if (!data) {
  		err = -ENOMEM;
  		dev_err(&pdev->dev, "Out of memory
  ");
  		goto exit;
  	}
  
  	data->id = pdev->id;
  #ifdef CONFIG_SMP
  	data->phys_proc_id = c->phys_proc_id;
  #endif
  	data->name = "pkgtemp";
  	mutex_init(&data->update_lock);
  
  	/* test if we can access the THERM_STATUS MSR */
  	err = rdmsr_safe_on_cpu(data->id, MSR_IA32_PACKAGE_THERM_STATUS,
  				&eax, &edx);
  	if (err) {
  		dev_err(&pdev->dev,
  			"Unable to access THERM_STATUS MSR, giving up
  ");
  		goto exit_free;
  	}
  
  	data->tjmax = get_tjmax(data->id, &pdev->dev);
  	platform_set_drvdata(pdev, data);
  
  	err = rdmsr_safe_on_cpu(data->id, MSR_IA32_TEMPERATURE_TARGET,
  				&eax, &edx);
  	if (err) {
  		dev_warn(&pdev->dev, "Unable to read"
  				" IA32_TEMPERATURE_TARGET MSR
  ");
  	} else {
  		data->ttarget = data->tjmax - (((eax >> 8) & 0xff) * 1000);
  		err = device_create_file(&pdev->dev,
  				&sensor_dev_attr_temp1_max.dev_attr);
  		if (err)
  			goto exit_free;
  	}
  
  	err = sysfs_create_group(&pdev->dev.kobj, &pkgtemp_group);
  	if (err)

  		goto exit_dev;

  
  	data->hwmon_dev = hwmon_device_register(&pdev->dev);
  	if (IS_ERR(data->hwmon_dev)) {
  		err = PTR_ERR(data->hwmon_dev);
  		dev_err(&pdev->dev, "Class registration failed (%d)
  ",
  			err);
  		goto exit_class;
  	}
  
  	return 0;
  
  exit_class:
  	sysfs_remove_group(&pdev->dev.kobj, &pkgtemp_group);

  exit_dev:
  	device_remove_file(&pdev->dev, &sensor_dev_attr_temp1_max.dev_attr);

  exit_free:
  	kfree(data);
  exit:
  	return err;
  }
  
  static int __devexit pkgtemp_remove(struct platform_device *pdev)
  {
  	struct pkgtemp_data *data = platform_get_drvdata(pdev);
  
  	hwmon_device_unregister(data->hwmon_dev);
  	sysfs_remove_group(&pdev->dev.kobj, &pkgtemp_group);

  	device_remove_file(&pdev->dev, &sensor_dev_attr_temp1_max.dev_attr);

  	platform_set_drvdata(pdev, NULL);
  	kfree(data);
  	return 0;
  }
  
  static struct platform_driver pkgtemp_driver = {
  	.driver = {
  		.owner = THIS_MODULE,
  		.name = DRVNAME,
  	},
  	.probe = pkgtemp_probe,
  	.remove = __devexit_p(pkgtemp_remove),
  };
  
  struct pdev_entry {
  	struct list_head list;
  	struct platform_device *pdev;
  	unsigned int cpu;
  #ifdef CONFIG_SMP
  	u16 phys_proc_id;
  #endif
  };
  
  static LIST_HEAD(pdev_list);
  static DEFINE_MUTEX(pdev_list_mutex);
  
  static int __cpuinit pkgtemp_device_add(unsigned int cpu)
  {
  	int err;
  	struct platform_device *pdev;
  	struct pdev_entry *pdev_entry;

  	struct cpuinfo_x86 *c = &cpu_data(cpu);

  
  	if (!cpu_has(c, X86_FEATURE_PTS))
  		return 0;

  
  	mutex_lock(&pdev_list_mutex);
  
  #ifdef CONFIG_SMP
  	/* Only keep the first entry in each package */
  	list_for_each_entry(pdev_entry, &pdev_list, list) {
  		if (c->phys_proc_id == pdev_entry->phys_proc_id) {
  			err = 0;        /* Not an error */
  			goto exit;
  		}
  	}
  #endif
  
  	pdev = platform_device_alloc(DRVNAME, cpu);
  	if (!pdev) {
  		err = -ENOMEM;
  		printk(KERN_ERR DRVNAME ": Device allocation failed
  ");
  		goto exit;
  	}
  
  	pdev_entry = kzalloc(sizeof(struct pdev_entry), GFP_KERNEL);
  	if (!pdev_entry) {
  		err = -ENOMEM;
  		goto exit_device_put;
  	}
  
  	err = platform_device_add(pdev);
  	if (err) {
  		printk(KERN_ERR DRVNAME ": Device addition failed (%d)
  ",
  		       err);
  		goto exit_device_free;
  	}
  
  #ifdef CONFIG_SMP
  	pdev_entry->phys_proc_id = c->phys_proc_id;
  #endif
  	pdev_entry->pdev = pdev;
  	pdev_entry->cpu = cpu;
  	list_add_tail(&pdev_entry->list, &pdev_list);
  	mutex_unlock(&pdev_list_mutex);
  
  	return 0;
  
  exit_device_free:
  	kfree(pdev_entry);
  exit_device_put:
  	platform_device_put(pdev);
  exit:
  	mutex_unlock(&pdev_list_mutex);
  	return err;
  }
  
  #ifdef CONFIG_HOTPLUG_CPU
  static void pkgtemp_device_remove(unsigned int cpu)
  {

  	struct pdev_entry *p;

  	unsigned int i;
  	int err;
  
  	mutex_lock(&pdev_list_mutex);

  	list_for_each_entry(p, &pdev_list, list) {

  		if (p->cpu != cpu)
  			continue;
  
  		platform_device_unregister(p->pdev);
  		list_del(&p->list);

  		mutex_unlock(&pdev_list_mutex);

  		kfree(p);
  		for_each_cpu(i, cpu_core_mask(cpu)) {
  			if (i != cpu) {
  				err = pkgtemp_device_add(i);
  				if (!err)
  					break;
  			}
  		}

  		return;

  	}
  	mutex_unlock(&pdev_list_mutex);
  }
  
  static int __cpuinit pkgtemp_cpu_callback(struct notifier_block *nfb,
  				 unsigned long action, void *hcpu)
  {
  	unsigned int cpu = (unsigned long) hcpu;
  
  	switch (action) {
  	case CPU_ONLINE:
  	case CPU_DOWN_FAILED:
  		pkgtemp_device_add(cpu);
  		break;
  	case CPU_DOWN_PREPARE:
  		pkgtemp_device_remove(cpu);
  		break;
  	}
  	return NOTIFY_OK;
  }
  
  static struct notifier_block pkgtemp_cpu_notifier __refdata = {
  	.notifier_call = pkgtemp_cpu_callback,
  };
  #endif				/* !CONFIG_HOTPLUG_CPU */
  
  static int __init pkgtemp_init(void)
  {
  	int i, err = -ENODEV;
  	struct pdev_entry *p, *n;
  
  	/* quick check if we run Intel */
  	if (cpu_data(0).x86_vendor != X86_VENDOR_INTEL)
  		goto exit;
  
  	err = platform_driver_register(&pkgtemp_driver);
  	if (err)
  		goto exit;
  
  	for_each_online_cpu(i) {

  		err = pkgtemp_device_add(i);
  		if (err)
  			goto exit_devices_unreg;
  	}
  	if (list_empty(&pdev_list)) {
  		err = -ENODEV;
  		goto exit_driver_unreg;
  	}
  
  #ifdef CONFIG_HOTPLUG_CPU
  	register_hotcpu_notifier(&pkgtemp_cpu_notifier);
  #endif
  	return 0;
  
  exit_devices_unreg:
  	mutex_lock(&pdev_list_mutex);
  	list_for_each_entry_safe(p, n, &pdev_list, list) {
  		platform_device_unregister(p->pdev);
  		list_del(&p->list);
  		kfree(p);
  	}
  	mutex_unlock(&pdev_list_mutex);
  exit_driver_unreg:
  	platform_driver_unregister(&pkgtemp_driver);
  exit:
  	return err;
  }
  
  static void __exit pkgtemp_exit(void)
  {
  	struct pdev_entry *p, *n;
  #ifdef CONFIG_HOTPLUG_CPU
  	unregister_hotcpu_notifier(&pkgtemp_cpu_notifier);
  #endif
  	mutex_lock(&pdev_list_mutex);
  	list_for_each_entry_safe(p, n, &pdev_list, list) {
  		platform_device_unregister(p->pdev);
  		list_del(&p->list);
  		kfree(p);
  	}
  	mutex_unlock(&pdev_list_mutex);
  	platform_driver_unregister(&pkgtemp_driver);
  }
  
  MODULE_AUTHOR("Fenghua Yu <fenghua.yu@intel.com>");
  MODULE_DESCRIPTION("Intel processor package temperature monitor");
  MODULE_LICENSE("GPL");
  
  module_init(pkgtemp_init)
  module_exit(pkgtemp_exit)