/*
   * via-cputemp.c - Driver for VIA CPU core temperature monitoring
   * Copyright (C) 2009 VIA Technologies, Inc.
   *
   * based on existing coretemp.c, which is
   *
   * Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
   *
   * 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/hwmon.h>

  #include <linux/hwmon-vid.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	"via_cputemp"

  enum { SHOW_TEMP, SHOW_LABEL, SHOW_NAME };

  
  /*
   * Functions declaration
   */
  
  struct via_cputemp_data {
  	struct device *hwmon_dev;
  	const char *name;

  	u8 vrm;

  	u32 id;

  	u32 msr_temp;
  	u32 msr_vid;

  };
  
  /*
   * 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 via_cputemp_data *data = dev_get_drvdata(dev);
  
  	if (attr->index == SHOW_NAME)
  		ret = sprintf(buf, "%s
  ", data->name);
  	else	/* show label */
  		ret = sprintf(buf, "Core %d
  ", data->id);
  	return ret;
  }
  
  static ssize_t show_temp(struct device *dev,
  			 struct device_attribute *devattr, char *buf)
  {
  	struct via_cputemp_data *data = dev_get_drvdata(dev);
  	u32 eax, edx;
  	int err;

  	err = rdmsr_safe_on_cpu(data->id, data->msr_temp, &eax, &edx);

  	if (err)
  		return -EAGAIN;
  
  	return sprintf(buf, "%lu
  ", ((unsigned long)eax & 0xffffff) * 1000);
  }

  static ssize_t show_cpu_vid(struct device *dev,
  			    struct device_attribute *devattr, char *buf)
  {
  	struct via_cputemp_data *data = dev_get_drvdata(dev);
  	u32 eax, edx;
  	int err;
  
  	err = rdmsr_safe_on_cpu(data->id, data->msr_vid, &eax, &edx);
  	if (err)
  		return -EAGAIN;
  
  	return sprintf(buf, "%d
  ", vid_from_reg(~edx & 0x7f, data->vrm));
  }

  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL,
  			  SHOW_TEMP);
  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 *via_cputemp_attributes[] = {
  	&sensor_dev_attr_name.dev_attr.attr,
  	&sensor_dev_attr_temp1_label.dev_attr.attr,
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group via_cputemp_group = {
  	.attrs = via_cputemp_attributes,
  };

  /* Optional attributes */
  static DEVICE_ATTR(cpu0_vid, S_IRUGO, show_cpu_vid, NULL);

  static int __devinit via_cputemp_probe(struct platform_device *pdev)
  {
  	struct via_cputemp_data *data;
  	struct cpuinfo_x86 *c = &cpu_data(pdev->id);
  	int err;
  	u32 eax, edx;
  
  	data = kzalloc(sizeof(struct via_cputemp_data), GFP_KERNEL);
  	if (!data) {
  		err = -ENOMEM;
  		dev_err(&pdev->dev, "Out of memory
  ");
  		goto exit;
  	}
  
  	data->id = pdev->id;
  	data->name = "via_cputemp";
  
  	switch (c->x86_model) {
  	case 0xA:
  		/* C7 A */
  	case 0xD:
  		/* C7 D */

  		data->msr_temp = 0x1169;
  		data->msr_vid = 0x198;

  		break;
  	case 0xF:
  		/* Nano */

  		data->msr_temp = 0x1423;

  		break;
  	default:
  		err = -ENODEV;
  		goto exit_free;
  	}
  
  	/* test if we can access the TEMPERATURE MSR */

  	err = rdmsr_safe_on_cpu(data->id, data->msr_temp, &eax, &edx);

  	if (err) {
  		dev_err(&pdev->dev,
  			"Unable to access TEMPERATURE MSR, giving up
  ");
  		goto exit_free;
  	}
  
  	platform_set_drvdata(pdev, data);
  
  	err = sysfs_create_group(&pdev->dev.kobj, &via_cputemp_group);
  	if (err)
  		goto exit_free;

  	if (data->msr_vid)
  		data->vrm = vid_which_vrm();
  
  	if (data->vrm) {
  		err = device_create_file(&pdev->dev, &dev_attr_cpu0_vid);
  		if (err)
  			goto exit_remove;
  	}

  	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_remove;
  	}
  
  	return 0;
  
  exit_remove:

  	if (data->vrm)
  		device_remove_file(&pdev->dev, &dev_attr_cpu0_vid);

  	sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
  exit_free:
  	platform_set_drvdata(pdev, NULL);
  	kfree(data);
  exit:
  	return err;
  }
  
  static int __devexit via_cputemp_remove(struct platform_device *pdev)
  {
  	struct via_cputemp_data *data = platform_get_drvdata(pdev);
  
  	hwmon_device_unregister(data->hwmon_dev);

  	if (data->vrm)
  		device_remove_file(&pdev->dev, &dev_attr_cpu0_vid);

  	sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
  	platform_set_drvdata(pdev, NULL);
  	kfree(data);
  	return 0;
  }
  
  static struct platform_driver via_cputemp_driver = {
  	.driver = {
  		.owner = THIS_MODULE,
  		.name = DRVNAME,
  	},
  	.probe = via_cputemp_probe,
  	.remove = __devexit_p(via_cputemp_remove),
  };
  
  struct pdev_entry {
  	struct list_head list;
  	struct platform_device *pdev;
  	unsigned int cpu;
  };
  
  static LIST_HEAD(pdev_list);
  static DEFINE_MUTEX(pdev_list_mutex);
  
  static int __cpuinit via_cputemp_device_add(unsigned int cpu)
  {
  	int err;
  	struct platform_device *pdev;
  	struct pdev_entry *pdev_entry;
  
  	pdev = platform_device_alloc(DRVNAME, cpu);
  	if (!pdev) {
  		err = -ENOMEM;

  		pr_err("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) {

  		pr_err("Device addition failed (%d)
  ", err);

  		goto exit_device_free;
  	}
  
  	pdev_entry->pdev = pdev;
  	pdev_entry->cpu = cpu;
  	mutex_lock(&pdev_list_mutex);
  	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:
  	return err;
  }

  static void __cpuinit via_cputemp_device_remove(unsigned int cpu)

  {

  	struct pdev_entry *p;

  	mutex_lock(&pdev_list_mutex);

  	list_for_each_entry(p, &pdev_list, list) {

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

  			mutex_unlock(&pdev_list_mutex);

  			kfree(p);

  			return;

  		}
  	}
  	mutex_unlock(&pdev_list_mutex);
  }
  
  static int __cpuinit via_cputemp_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:
  		via_cputemp_device_add(cpu);
  		break;
  	case CPU_DOWN_PREPARE:
  		via_cputemp_device_remove(cpu);
  		break;
  	}
  	return NOTIFY_OK;
  }
  
  static struct notifier_block via_cputemp_cpu_notifier __refdata = {
  	.notifier_call = via_cputemp_cpu_callback,
  };

  
  static int __init via_cputemp_init(void)
  {
  	int i, err;

  
  	if (cpu_data(0).x86_vendor != X86_VENDOR_CENTAUR) {
  		printk(KERN_DEBUG DRVNAME ": Not a VIA CPU
  ");
  		err = -ENODEV;
  		goto exit;
  	}
  
  	err = platform_driver_register(&via_cputemp_driver);
  	if (err)
  		goto exit;
  
  	for_each_online_cpu(i) {
  		struct cpuinfo_x86 *c = &cpu_data(i);
  
  		if (c->x86 != 6)
  			continue;
  
  		if (c->x86_model < 0x0a)
  			continue;
  
  		if (c->x86_model > 0x0f) {

  			pr_warn("Unknown CPU model 0x%x
  ", c->x86_model);

  			continue;
  		}

  		via_cputemp_device_add(i);

  	}

  
  #ifndef CONFIG_HOTPLUG_CPU

  	if (list_empty(&pdev_list)) {
  		err = -ENODEV;
  		goto exit_driver_unreg;
  	}

  #endif

  	register_hotcpu_notifier(&via_cputemp_cpu_notifier);

  	return 0;

  #ifndef CONFIG_HOTPLUG_CPU

  exit_driver_unreg:
  	platform_driver_unregister(&via_cputemp_driver);

  #endif

  exit:
  	return err;
  }
  
  static void __exit via_cputemp_exit(void)
  {
  	struct pdev_entry *p, *n;

  	unregister_hotcpu_notifier(&via_cputemp_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(&via_cputemp_driver);
  }
  
  MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
  MODULE_DESCRIPTION("VIA CPU temperature monitor");
  MODULE_LICENSE("GPL");
  
  module_init(via_cputemp_init)
  module_exit(via_cputemp_exit)