hwmon: Add driver for VIA CPU core temperature

This is a driver for the on-die digital temperature sensor of
VIA's recent CPU models.

[JD: Misc clean-ups.]

Signed-off-by: Harald Welte <HaraldWelte@viatech.com>
Cc: Juerg Haefliger <juergh@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Adam Nielsen <a.nielsen@shikadi.net>

3 files changed, 365 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 665947fbcdcb..be8eeadb2ee9 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -822,6 +822,14 @@ config SENSORS_TMP421
           This driver can also be built as a module.  If so, the module
           will be called tmp421.
 
+config SENSORS_VIA_CPUTEMP
+        tristate "VIA CPU temperature sensor"
+        depends on X86
+        help
+          If you say yes here you get support for the temperature
+          sensor inside your CPU. Supported are all known variants of
+          the VIA C7 and Nano.
+
 config SENSORS_VIA686A
         tristate "VIA686A"
         depends on PCI
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index da84a6a69593..312b7c39d9f4 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
 obj-$(CONFIG_SENSORS_THMC50)    += thmc50.o
 obj-$(CONFIG_SENSORS_TMP401)    += tmp401.o
 obj-$(CONFIG_SENSORS_TMP421)    += tmp421.o
+obj-$(CONFIG_SENSORS_VIA_CPUTEMP)+= via-cputemp.o
 obj-$(CONFIG_SENSORS_VIA686A)   += via686a.o
 obj-$(CONFIG_SENSORS_VT1211)    += vt1211.o
 obj-$(CONFIG_SENSORS_VT8231)    += vt8231.o
diff --git a/drivers/hwmon/via-cputemp.c b/drivers/hwmon/via-cputemp.c
new file mode 100644
index 000000000000..7442cf754856
--- /dev/null
+++ b/drivers/hwmon/via-cputemp.c
@@ -0,0 +1,356 @@
+/*
+ * 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.
+ */
+
+#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 "via_cputemp"
+
+enum { SHOW_TEMP, SHOW_LABEL, SHOW_NAME } SHOW;
+
+/*
+ * Functions declaration
+ */
+
+struct via_cputemp_data {
+        struct device *hwmon_dev;
+        const char *name;
+        u32 id;
+        u32 msr;
+};
+
+/*
+ * 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\n", data->name);
+        else    /* show label */
+                ret = sprintf(buf, "Core %d\n", 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, &eax, &edx);
+        if (err)
+                return -EAGAIN;
+
+        return sprintf(buf, "%lu\n", ((unsigned long)eax & 0xffffff) * 1000);
+}
+
+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,
+};
+
+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\n");
+                goto exit;
+        }
+
+        data->id = pdev->id;
+        data->name = "via_cputemp";
+
+        switch (c->x86_model) {
+        case 0xA:
+                /* C7 A */
+        case 0xD:
+                /* C7 D */
+                data->msr = 0x1169;
+                break;
+        case 0xF:
+                /* Nano */
+                data->msr = 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, &eax, &edx);
+        if (err) {
+                dev_err(&pdev->dev,
+                        "Unable to access TEMPERATURE MSR, giving up\n");
+                goto exit_free;
+        }
+
+        platform_set_drvdata(pdev, data);
+
+        err = sysfs_create_group(&pdev->dev.kobj, &via_cputemp_group);
+        if (err)
+                goto exit_free;
+
+        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_remove;
+        }
+
+        return 0;
+
+exit_remove:
+        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);
+        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;
+                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
+static void via_cputemp_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 __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,
+};
+#endif                          /* !CONFIG_HOTPLUG_CPU */
+
+static int __init via_cputemp_init(void)
+{
+        int i, err;
+        struct pdev_entry *p, *n;
+
+        if (cpu_data(0).x86_vendor != X86_VENDOR_CENTAUR) {
+                printk(KERN_DEBUG DRVNAME ": Not a VIA CPU\n");
+                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) {
+                        printk(KERN_WARNING DRVNAME ": Unknown CPU "
+                                "model 0x%x\n", c->x86_model);
+                        continue;
+                }
+
+                err = via_cputemp_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(&via_cputemp_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(&via_cputemp_driver);
+exit:
+        return err;
+}
+
+static void __exit via_cputemp_exit(void)
+{
+        struct pdev_entry *p, *n;
+#ifdef CONFIG_HOTPLUG_CPU
+        unregister_hotcpu_notifier(&via_cputemp_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(&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)