via-cputemp.c

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/*
 * 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 <[email protected]>
 *
 * 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>
#include <asm/cpu_device_id.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\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_temp, &eax, &edx);
    if (err)
        return -EAGAIN;

    return sprintf(buf, "%lu\n", ((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\n", 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 = devm_kzalloc(&pdev->dev, sizeof(struct via_cputemp_data),
                GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    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:
        return -ENODEV;
    }

    /* 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\n");
        return err;
    }

    platform_set_drvdata(pdev, data);

    err = sysfs_create_group(&pdev->dev.kobj, &via_cputemp_group);
    if (err)
        return err;

    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)\n",
            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);
    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);
    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\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;
    }

    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 const struct x86_cpu_id __initconst cputemp_ids[] = {
    { X86_VENDOR_CENTAUR, 6, 0xa, }, /* C7 A */
    { X86_VENDOR_CENTAUR, 6, 0xd, }, /* C7 D */
    { X86_VENDOR_CENTAUR, 6, 0xf, }, /* Nano */
    {}
};
MODULE_DEVICE_TABLE(x86cpu, cputemp_ids);

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

    if (!x86_match_cpu(cputemp_ids))
        return -ENODEV;

    err = platform_driver_register(&via_cputemp_driver);
    if (err)
        goto exit;

    get_online_cpus();
    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\n", c->x86_model);
            continue;
        }

        via_cputemp_device_add(i);
    }

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

    register_hotcpu_notifier(&via_cputemp_cpu_notifier);
    put_online_cpus();
    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;

    get_online_cpus();
    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);
    put_online_cpus();
    platform_driver_unregister(&via_cputemp_driver);
}

MODULE_AUTHOR("Harald Welte <[email protected]>");
MODULE_DESCRIPTION("VIA CPU temperature monitor");
MODULE_LICENSE("GPL");

module_init(via_cputemp_init)
module_exit(via_cputemp_exit)