/*
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.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>
#include <asm/smp.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\n", data->name);
	else	/* show label */
		ret = sprintf(buf, "physical id %d\n",
			      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\n", 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\n", data->temp) : -EAGAIN;
	else if (attr->index == SHOW_TJMAX)
		err = sprintf(buf, "%d\n", data->tjmax);
	else
		err = sprintf(buf, "%d\n", 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)\n", 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.\n", val);
			return val * 1000;
		}
	}
	dev_warn(dev, "Unable to read TjMax from CPU.\n");
	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\n");
		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\n");
		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\n");
	} 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)\n",
			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;
		pr_err("Device allocation failed\n");
		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) {
		pr_err("Device addition failed (%d)\n", 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;
}

static void __cpuinit 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,
};

static int __init pkgtemp_init(void)
{
	int i, err = -ENODEV;

	/* 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)
		pkgtemp_device_add(i);

#ifndef CONFIG_HOTPLUG_CPU
	if (list_empty(&pdev_list)) {
		err = -ENODEV;
		goto exit_driver_unreg;
	}
#endif

	register_hotcpu_notifier(&pkgtemp_cpu_notifier);
	return 0;

#ifndef CONFIG_HOTPLUG_CPU
exit_driver_unreg:
	platform_driver_unregister(&pkgtemp_driver);
#endif
exit:
	return err;
}

static void __exit pkgtemp_exit(void)
{
	struct pdev_entry *p, *n;

	unregister_hotcpu_notifier(&pkgtemp_cpu_notifier);
	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)