linux/drivers/hwmon/via-cputemp.c
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   1/*
   2 * via-cputemp.c - Driver for VIA CPU core temperature monitoring
   3 * Copyright (C) 2009 VIA Technologies, Inc.
   4 *
   5 * based on existing coretemp.c, which is
   6 *
   7 * Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License as published by
  11 * the Free Software Foundation; version 2 of the License.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  21 * 02110-1301 USA.
  22 */
  23
  24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  25
  26#include <linux/module.h>
  27#include <linux/init.h>
  28#include <linux/slab.h>
  29#include <linux/hwmon.h>
  30#include <linux/sysfs.h>
  31#include <linux/hwmon-sysfs.h>
  32#include <linux/err.h>
  33#include <linux/mutex.h>
  34#include <linux/list.h>
  35#include <linux/platform_device.h>
  36#include <linux/cpu.h>
  37#include <asm/msr.h>
  38#include <asm/processor.h>
  39
  40#define DRVNAME "via_cputemp"
  41
  42enum { SHOW_TEMP, SHOW_LABEL, SHOW_NAME };
  43
  44/*
  45 * Functions declaration
  46 */
  47
  48struct via_cputemp_data {
  49        struct device *hwmon_dev;
  50        const char *name;
  51        u32 id;
  52        u32 msr;
  53};
  54
  55/*
  56 * Sysfs stuff
  57 */
  58
  59static ssize_t show_name(struct device *dev, struct device_attribute
  60                          *devattr, char *buf)
  61{
  62        int ret;
  63        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  64        struct via_cputemp_data *data = dev_get_drvdata(dev);
  65
  66        if (attr->index == SHOW_NAME)
  67                ret = sprintf(buf, "%s\n", data->name);
  68        else    /* show label */
  69                ret = sprintf(buf, "Core %d\n", data->id);
  70        return ret;
  71}
  72
  73static ssize_t show_temp(struct device *dev,
  74                         struct device_attribute *devattr, char *buf)
  75{
  76        struct via_cputemp_data *data = dev_get_drvdata(dev);
  77        u32 eax, edx;
  78        int err;
  79
  80        err = rdmsr_safe_on_cpu(data->id, data->msr, &eax, &edx);
  81        if (err)
  82                return -EAGAIN;
  83
  84        return sprintf(buf, "%lu\n", ((unsigned long)eax & 0xffffff) * 1000);
  85}
  86
  87static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL,
  88                          SHOW_TEMP);
  89static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_name, NULL, SHOW_LABEL);
  90static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, SHOW_NAME);
  91
  92static struct attribute *via_cputemp_attributes[] = {
  93        &sensor_dev_attr_name.dev_attr.attr,
  94        &sensor_dev_attr_temp1_label.dev_attr.attr,
  95        &sensor_dev_attr_temp1_input.dev_attr.attr,
  96        NULL
  97};
  98
  99static const struct attribute_group via_cputemp_group = {
 100        .attrs = via_cputemp_attributes,
 101};
 102
 103static int __devinit via_cputemp_probe(struct platform_device *pdev)
 104{
 105        struct via_cputemp_data *data;
 106        struct cpuinfo_x86 *c = &cpu_data(pdev->id);
 107        int err;
 108        u32 eax, edx;
 109
 110        data = kzalloc(sizeof(struct via_cputemp_data), GFP_KERNEL);
 111        if (!data) {
 112                err = -ENOMEM;
 113                dev_err(&pdev->dev, "Out of memory\n");
 114                goto exit;
 115        }
 116
 117        data->id = pdev->id;
 118        data->name = "via_cputemp";
 119
 120        switch (c->x86_model) {
 121        case 0xA:
 122                /* C7 A */
 123        case 0xD:
 124                /* C7 D */
 125                data->msr = 0x1169;
 126                break;
 127        case 0xF:
 128                /* Nano */
 129                data->msr = 0x1423;
 130                break;
 131        default:
 132                err = -ENODEV;
 133                goto exit_free;
 134        }
 135
 136        /* test if we can access the TEMPERATURE MSR */
 137        err = rdmsr_safe_on_cpu(data->id, data->msr, &eax, &edx);
 138        if (err) {
 139                dev_err(&pdev->dev,
 140                        "Unable to access TEMPERATURE MSR, giving up\n");
 141                goto exit_free;
 142        }
 143
 144        platform_set_drvdata(pdev, data);
 145
 146        err = sysfs_create_group(&pdev->dev.kobj, &via_cputemp_group);
 147        if (err)
 148                goto exit_free;
 149
 150        data->hwmon_dev = hwmon_device_register(&pdev->dev);
 151        if (IS_ERR(data->hwmon_dev)) {
 152                err = PTR_ERR(data->hwmon_dev);
 153                dev_err(&pdev->dev, "Class registration failed (%d)\n",
 154                        err);
 155                goto exit_remove;
 156        }
 157
 158        return 0;
 159
 160exit_remove:
 161        sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
 162exit_free:
 163        platform_set_drvdata(pdev, NULL);
 164        kfree(data);
 165exit:
 166        return err;
 167}
 168
 169static int __devexit via_cputemp_remove(struct platform_device *pdev)
 170{
 171        struct via_cputemp_data *data = platform_get_drvdata(pdev);
 172
 173        hwmon_device_unregister(data->hwmon_dev);
 174        sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
 175        platform_set_drvdata(pdev, NULL);
 176        kfree(data);
 177        return 0;
 178}
 179
 180static struct platform_driver via_cputemp_driver = {
 181        .driver = {
 182                .owner = THIS_MODULE,
 183                .name = DRVNAME,
 184        },
 185        .probe = via_cputemp_probe,
 186        .remove = __devexit_p(via_cputemp_remove),
 187};
 188
 189struct pdev_entry {
 190        struct list_head list;
 191        struct platform_device *pdev;
 192        unsigned int cpu;
 193};
 194
 195static LIST_HEAD(pdev_list);
 196static DEFINE_MUTEX(pdev_list_mutex);
 197
 198static int __cpuinit via_cputemp_device_add(unsigned int cpu)
 199{
 200        int err;
 201        struct platform_device *pdev;
 202        struct pdev_entry *pdev_entry;
 203
 204        pdev = platform_device_alloc(DRVNAME, cpu);
 205        if (!pdev) {
 206                err = -ENOMEM;
 207                pr_err("Device allocation failed\n");
 208                goto exit;
 209        }
 210
 211        pdev_entry = kzalloc(sizeof(struct pdev_entry), GFP_KERNEL);
 212        if (!pdev_entry) {
 213                err = -ENOMEM;
 214                goto exit_device_put;
 215        }
 216
 217        err = platform_device_add(pdev);
 218        if (err) {
 219                pr_err("Device addition failed (%d)\n", err);
 220                goto exit_device_free;
 221        }
 222
 223        pdev_entry->pdev = pdev;
 224        pdev_entry->cpu = cpu;
 225        mutex_lock(&pdev_list_mutex);
 226        list_add_tail(&pdev_entry->list, &pdev_list);
 227        mutex_unlock(&pdev_list_mutex);
 228
 229        return 0;
 230
 231exit_device_free:
 232        kfree(pdev_entry);
 233exit_device_put:
 234        platform_device_put(pdev);
 235exit:
 236        return err;
 237}
 238
 239static void __cpuinit via_cputemp_device_remove(unsigned int cpu)
 240{
 241        struct pdev_entry *p;
 242
 243        mutex_lock(&pdev_list_mutex);
 244        list_for_each_entry(p, &pdev_list, list) {
 245                if (p->cpu == cpu) {
 246                        platform_device_unregister(p->pdev);
 247                        list_del(&p->list);
 248                        mutex_unlock(&pdev_list_mutex);
 249                        kfree(p);
 250                        return;
 251                }
 252        }
 253        mutex_unlock(&pdev_list_mutex);
 254}
 255
 256static int __cpuinit via_cputemp_cpu_callback(struct notifier_block *nfb,
 257                                 unsigned long action, void *hcpu)
 258{
 259        unsigned int cpu = (unsigned long) hcpu;
 260
 261        switch (action) {
 262        case CPU_ONLINE:
 263        case CPU_DOWN_FAILED:
 264                via_cputemp_device_add(cpu);
 265                break;
 266        case CPU_DOWN_PREPARE:
 267                via_cputemp_device_remove(cpu);
 268                break;
 269        }
 270        return NOTIFY_OK;
 271}
 272
 273static struct notifier_block via_cputemp_cpu_notifier __refdata = {
 274        .notifier_call = via_cputemp_cpu_callback,
 275};
 276
 277static int __init via_cputemp_init(void)
 278{
 279        int i, err;
 280
 281        if (cpu_data(0).x86_vendor != X86_VENDOR_CENTAUR) {
 282                printk(KERN_DEBUG DRVNAME ": Not a VIA CPU\n");
 283                err = -ENODEV;
 284                goto exit;
 285        }
 286
 287        err = platform_driver_register(&via_cputemp_driver);
 288        if (err)
 289                goto exit;
 290
 291        for_each_online_cpu(i) {
 292                struct cpuinfo_x86 *c = &cpu_data(i);
 293
 294                if (c->x86 != 6)
 295                        continue;
 296
 297                if (c->x86_model < 0x0a)
 298                        continue;
 299
 300                if (c->x86_model > 0x0f) {
 301                        pr_warn("Unknown CPU model 0x%x\n", c->x86_model);
 302                        continue;
 303                }
 304
 305                via_cputemp_device_add(i);
 306        }
 307
 308#ifndef CONFIG_HOTPLUG_CPU
 309        if (list_empty(&pdev_list)) {
 310                err = -ENODEV;
 311                goto exit_driver_unreg;
 312        }
 313#endif
 314
 315        register_hotcpu_notifier(&via_cputemp_cpu_notifier);
 316        return 0;
 317
 318#ifndef CONFIG_HOTPLUG_CPU
 319exit_driver_unreg:
 320        platform_driver_unregister(&via_cputemp_driver);
 321#endif
 322exit:
 323        return err;
 324}
 325
 326static void __exit via_cputemp_exit(void)
 327{
 328        struct pdev_entry *p, *n;
 329
 330        unregister_hotcpu_notifier(&via_cputemp_cpu_notifier);
 331        mutex_lock(&pdev_list_mutex);
 332        list_for_each_entry_safe(p, n, &pdev_list, list) {
 333                platform_device_unregister(p->pdev);
 334                list_del(&p->list);
 335                kfree(p);
 336        }
 337        mutex_unlock(&pdev_list_mutex);
 338        platform_driver_unregister(&via_cputemp_driver);
 339}
 340
 341MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
 342MODULE_DESCRIPTION("VIA CPU temperature monitor");
 343MODULE_LICENSE("GPL");
 344
 345module_init(via_cputemp_init)
 346module_exit(via_cputemp_exit)
 347