hwmon: New coretemp driver

Add the support for the digital temperature sensor found in recent
Intel Core CPUs.

Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 406 insertions, 0 deletions

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
new file mode 100644
index 000000000000..03b1f650d1c4
--- /dev/null
+++ b/drivers/hwmon/coretemp.c
@@ -0,0 +1,406 @@
+/*
+ * coretemp.c - Linux kernel module for hardware monitoring
+ *
+ * Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
+ *
+ * Inspired from many hwmon drivers
+ *
+ * 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	"coretemp"
+
+typedef enum { SHOW_TEMP, SHOW_TJMAX, SHOW_LABEL, SHOW_NAME } SHOW;
+
+/*
+ * Functions declaration
+ */
+
+static struct coretemp_data *coretemp_update_device(struct device *dev);
+
+struct coretemp_data {
+	struct class_device *class_dev;
+	struct mutex update_lock;
+	const char *name;
+	u32 id;
+	char valid;		/* zero until following fields are valid */
+	unsigned long last_updated;	/* in jiffies */
+	int temp;
+	int tjmax;
+	u8 alarm;
+};
+
+static struct coretemp_data *coretemp_update_device(struct device *dev);
+
+/*
+ * 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 coretemp_data *data = dev_get_drvdata(dev);
+
+	if (attr->index == SHOW_NAME)
+		ret = sprintf(buf, "%s\n", data->name);
+	else	/* show label */
+		ret = sprintf(buf, "Core %d\n", data->id);
+	return ret;
+}
+
+static ssize_t show_alarm(struct device *dev, struct device_attribute
+			  *devattr, char *buf)
+{
+	struct coretemp_data *data = coretemp_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 coretemp_data *data = coretemp_update_device(dev);
+	int err;
+
+	if (attr->index == SHOW_TEMP)
+		err = data->valid ? sprintf(buf, "%d\n", data->temp) : -EAGAIN;
+	else
+		err = sprintf(buf, "%d\n", data->tjmax);
+
+	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 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 *coretemp_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 coretemp_group = {
+	.attrs = coretemp_attributes,
+};
+
+static struct coretemp_data *coretemp_update_device(struct device *dev)
+{
+	struct coretemp_data *data = dev_get_drvdata(dev);
+
+	mutex_lock(&data->update_lock);
+
+	if (!data->valid || time_after(jiffies, data->last_updated + HZ)) {
+		u32 eax, edx;
+
+		data->valid = 0;
+		rdmsr_on_cpu(data->id, MSR_IA32_THERM_STATUS, &eax, &edx);
+		data->alarm = (eax >> 5) & 1;
+		/* update only if data has been valid */
+		if (eax & 0x80000000) {
+			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 __devinit coretemp_probe(struct platform_device *pdev)
+{
+	struct coretemp_data *data;
+	struct cpuinfo_x86 *c = &(cpu_data)[pdev->id];
+	int err;
+	u32 eax, edx;
+
+	if (!(data = kzalloc(sizeof(struct coretemp_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		dev_err(&pdev->dev, "Out of memory\n");
+		goto exit;
+	}
+
+	data->id = pdev->id;
+	data->name = "coretemp";
+	mutex_init(&data->update_lock);
+	/* Tjmax default is 100 degrees C */
+	data->tjmax = 100000;
+
+	/* test if we can access the THERM_STATUS MSR */
+	err = rdmsr_safe_on_cpu(data->id, MSR_IA32_THERM_STATUS, &eax, &edx);
+	if (err) {
+		dev_err(&pdev->dev,
+			"Unable to access THERM_STATUS MSR, giving up\n");
+		goto exit_free;
+	}
+
+	/* Some processors have Tjmax 85 following magic should detect it
+	   Intel won't disclose the information without signed NDA, but
+	   individuals cannot sign it. Catch(ed) 22.
+	*/
+
+	if (((c->x86_model == 0xf) && (c->x86_mask > 3)) ||
+		(c->x86_model == 0xe))  {
+		err = rdmsr_safe_on_cpu(data->id, 0xee, &eax, &edx);
+		if (err) {
+			dev_warn(&pdev->dev,
+				 "Unable to access MSR 0xEE, Tjmax left at %d "
+				 "degrees C\n", data->tjmax/1000);
+		} else if (eax & 0x40000000) {
+			data->tjmax = 85000;
+		}
+	}
+
+	platform_set_drvdata(pdev, data);
+
+	if ((err = sysfs_create_group(&pdev->dev.kobj, &coretemp_group)))
+		goto exit_free;
+
+	data->class_dev = hwmon_device_register(&pdev->dev);
+	if (IS_ERR(data->class_dev)) {
+		err = PTR_ERR(data->class_dev);
+		dev_err(&pdev->dev, "Class registration failed (%d)\n",
+			err);
+		goto exit_class;
+	}
+
+	return 0;
+
+exit_class:
+	sysfs_remove_group(&pdev->dev.kobj, &coretemp_group);
+exit_free:
+	kfree(data);
+exit:
+	return err;
+}
+
+static int __devexit coretemp_remove(struct platform_device *pdev)
+{
+	struct coretemp_data *data = platform_get_drvdata(pdev);
+
+	hwmon_device_unregister(data->class_dev);
+	sysfs_remove_group(&pdev->dev.kobj, &coretemp_group);
+	platform_set_drvdata(pdev, NULL);
+	kfree(data);
+	return 0;
+}
+
+static struct platform_driver coretemp_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = DRVNAME,
+	},
+	.probe = coretemp_probe,
+	.remove = __devexit_p(coretemp_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 coretemp_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;
+		printk(KERN_ERR DRVNAME ": 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) {
+		printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n",
+		       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;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void coretemp_device_remove(unsigned int cpu)
+{
+	struct pdev_entry *p, *n;
+	mutex_lock(&pdev_list_mutex);
+	list_for_each_entry_safe(p, n, &pdev_list, list) {
+		if (p->cpu == cpu) {
+			platform_device_unregister(p->pdev);
+			list_del(&p->list);
+			kfree(p);
+		}
+	}
+	mutex_unlock(&pdev_list_mutex);
+}
+
+static int coretemp_cpu_callback(struct notifier_block *nfb,
+				 unsigned long action, void *hcpu)
+{
+	unsigned int cpu = (unsigned long) hcpu;
+
+	switch (action) {
+	case CPU_ONLINE:
+		coretemp_device_add(cpu);
+		break;
+	case CPU_DEAD:
+		coretemp_device_remove(cpu);
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata coretemp_cpu_notifier = {
+	.notifier_call = coretemp_cpu_callback,
+};
+#endif				/* !CONFIG_HOTPLUG_CPU */
+
+static int __init coretemp_init(void)
+{
+	int i, err = -ENODEV;
+	struct pdev_entry *p, *n;
+
+	printk(KERN_NOTICE DRVNAME ": This driver uses undocumented features "
+		"of Core CPU. Temperature might be wrong!\n");
+
+	/* quick check if we run Intel */
+	if (cpu_data[0].x86_vendor != X86_VENDOR_INTEL)
+		goto exit;
+
+	err = platform_driver_register(&coretemp_driver);
+	if (err)
+		goto exit;
+
+	for_each_online_cpu(i) {
+		struct cpuinfo_x86 *c = &(cpu_data)[i];
+
+		/* check if family 6, models e, f */
+		if ((c->cpuid_level < 0) || (c->x86 != 0x6) ||
+		    !((c->x86_model == 0xe) || (c->x86_model == 0xf))) {
+
+			/* supported CPU not found, but report the unknown
+			   family 6 CPU */
+			if ((c->x86 == 0x6) && (c->x86_model > 0xf))
+				printk(KERN_WARNING DRVNAME ": Unknown CPU "
+					"model %x\n", c->x86_model);
+			continue;
+		}
+
+		err = coretemp_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(&coretemp_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(&coretemp_driver);
+exit:
+	return err;
+}
+
+static void __exit coretemp_exit(void)
+{
+	struct pdev_entry *p, *n;
+#ifdef CONFIG_HOTPLUG_CPU
+	unregister_hotcpu_notifier(&coretemp_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(&coretemp_driver);
+}
+
+MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
+MODULE_DESCRIPTION("Intel Core temperature monitor");
+MODULE_LICENSE("GPL");
+
+module_init(coretemp_init)
+module_exit(coretemp_exit)