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>

3 files changed, 415 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 659a2abb3e90..e488d691da4a 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -229,6 +229,14 @@ config SENSORS_GL520SM
           This driver can also be built as a module.  If so, the module
           will be called gl520sm.
 
+config SENSORS_CORETEMP
+        tristate "Intel Core (2) Duo/Solo temperature sensor"
+        depends on HWMON && X86 && EXPERIMENTAL
+        help
+          If you say yes here you get support for the temperature
+          sensor inside your CPU. Supported all are all known variants
+          of Intel Core family.
+
 config SENSORS_IT87
         tristate "ITE IT87xx and compatibles"
         depends on HWMON && I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index bbbe86bf5da1..33780678bd4b 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_SENSORS_ADM1031)	+= adm1031.o
 obj-$(CONFIG_SENSORS_ADM9240)   += adm9240.o
 obj-$(CONFIG_SENSORS_AMS)       += ams/
 obj-$(CONFIG_SENSORS_ATXP1)     += atxp1.o
+obj-$(CONFIG_SENSORS_CORETEMP)  += coretemp.o
 obj-$(CONFIG_SENSORS_DS1621)    += ds1621.o
 obj-$(CONFIG_SENSORS_F71805F)   += f71805f.o
 obj-$(CONFIG_SENSORS_FSCHER)    += fscher.o
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)