linux/drivers/hwmon/coretemp.c
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   1/*
   2 * coretemp.c - Linux kernel module for hardware monitoring
   3 *
   4 * Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
   5 *
   6 * Inspired from many hwmon drivers
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; version 2 of the License.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20 * 02110-1301 USA.
  21 */
  22
  23#include <linux/module.h>
  24#include <linux/delay.h>
  25#include <linux/init.h>
  26#include <linux/slab.h>
  27#include <linux/jiffies.h>
  28#include <linux/hwmon.h>
  29#include <linux/sysfs.h>
  30#include <linux/hwmon-sysfs.h>
  31#include <linux/err.h>
  32#include <linux/mutex.h>
  33#include <linux/list.h>
  34#include <linux/platform_device.h>
  35#include <linux/cpu.h>
  36#include <asm/msr.h>
  37#include <asm/processor.h>
  38
  39#define DRVNAME "coretemp"
  40
  41typedef enum { SHOW_TEMP, SHOW_TJMAX, SHOW_TTARGET, SHOW_LABEL,
  42                SHOW_NAME } SHOW;
  43
  44/*
  45 * Functions declaration
  46 */
  47
  48static struct coretemp_data *coretemp_update_device(struct device *dev);
  49
  50struct coretemp_data {
  51        struct device *hwmon_dev;
  52        struct mutex update_lock;
  53        const char *name;
  54        u32 id;
  55        char valid;             /* zero until following fields are valid */
  56        unsigned long last_updated;     /* in jiffies */
  57        int temp;
  58        int tjmax;
  59        int ttarget;
  60        u8 alarm;
  61};
  62
  63/*
  64 * Sysfs stuff
  65 */
  66
  67static ssize_t show_name(struct device *dev, struct device_attribute
  68                          *devattr, char *buf)
  69{
  70        int ret;
  71        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  72        struct coretemp_data *data = dev_get_drvdata(dev);
  73
  74        if (attr->index == SHOW_NAME)
  75                ret = sprintf(buf, "%s\n", data->name);
  76        else    /* show label */
  77                ret = sprintf(buf, "Core %d\n", data->id);
  78        return ret;
  79}
  80
  81static ssize_t show_alarm(struct device *dev, struct device_attribute
  82                          *devattr, char *buf)
  83{
  84        struct coretemp_data *data = coretemp_update_device(dev);
  85        /* read the Out-of-spec log, never clear */
  86        return sprintf(buf, "%d\n", data->alarm);
  87}
  88
  89static ssize_t show_temp(struct device *dev,
  90                         struct device_attribute *devattr, char *buf)
  91{
  92        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  93        struct coretemp_data *data = coretemp_update_device(dev);
  94        int err;
  95
  96        if (attr->index == SHOW_TEMP)
  97                err = data->valid ? sprintf(buf, "%d\n", data->temp) : -EAGAIN;
  98        else if (attr->index == SHOW_TJMAX)
  99                err = sprintf(buf, "%d\n", data->tjmax);
 100        else
 101                err = sprintf(buf, "%d\n", data->ttarget);
 102        return err;
 103}
 104
 105static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL,
 106                          SHOW_TEMP);
 107static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_temp, NULL,
 108                          SHOW_TJMAX);
 109static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL,
 110                          SHOW_TTARGET);
 111static DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL);
 112static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_name, NULL, SHOW_LABEL);
 113static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, SHOW_NAME);
 114
 115static struct attribute *coretemp_attributes[] = {
 116        &sensor_dev_attr_name.dev_attr.attr,
 117        &sensor_dev_attr_temp1_label.dev_attr.attr,
 118        &dev_attr_temp1_crit_alarm.attr,
 119        &sensor_dev_attr_temp1_input.dev_attr.attr,
 120        &sensor_dev_attr_temp1_crit.dev_attr.attr,
 121        NULL
 122};
 123
 124static const struct attribute_group coretemp_group = {
 125        .attrs = coretemp_attributes,
 126};
 127
 128static struct coretemp_data *coretemp_update_device(struct device *dev)
 129{
 130        struct coretemp_data *data = dev_get_drvdata(dev);
 131
 132        mutex_lock(&data->update_lock);
 133
 134        if (!data->valid || time_after(jiffies, data->last_updated + HZ)) {
 135                u32 eax, edx;
 136
 137                data->valid = 0;
 138                rdmsr_on_cpu(data->id, MSR_IA32_THERM_STATUS, &eax, &edx);
 139                data->alarm = (eax >> 5) & 1;
 140                /* update only if data has been valid */
 141                if (eax & 0x80000000) {
 142                        data->temp = data->tjmax - (((eax >> 16)
 143                                                        & 0x7f) * 1000);
 144                        data->valid = 1;
 145                } else {
 146                        dev_dbg(dev, "Temperature data invalid (0x%x)\n", eax);
 147                }
 148                data->last_updated = jiffies;
 149        }
 150
 151        mutex_unlock(&data->update_lock);
 152        return data;
 153}
 154
 155static int __devinit adjust_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *dev)
 156{
 157        /* The 100C is default for both mobile and non mobile CPUs */
 158
 159        int tjmax = 100000;
 160        int tjmax_ee = 85000;
 161        int usemsr_ee = 1;
 162        int err;
 163        u32 eax, edx;
 164
 165        /* Early chips have no MSR for TjMax */
 166
 167        if ((c->x86_model == 0xf) && (c->x86_mask < 4)) {
 168                usemsr_ee = 0;
 169        }
 170
 171        /* Atoms seems to have TjMax at 90C */
 172
 173        if (c->x86_model == 0x1c) {
 174                usemsr_ee = 0;
 175                tjmax = 90000;
 176        }
 177
 178        if ((c->x86_model > 0xe) && (usemsr_ee)) {
 179                u8 platform_id;
 180
 181                /* Now we can detect the mobile CPU using Intel provided table
 182                   http://softwarecommunity.intel.com/Wiki/Mobility/720.htm
 183                   For Core2 cores, check MSR 0x17, bit 28 1 = Mobile CPU
 184                */
 185
 186                err = rdmsr_safe_on_cpu(id, 0x17, &eax, &edx);
 187                if (err) {
 188                        dev_warn(dev,
 189                                 "Unable to access MSR 0x17, assuming desktop"
 190                                 " CPU\n");
 191                        usemsr_ee = 0;
 192                } else if (c->x86_model < 0x17 && !(eax & 0x10000000)) {
 193                        /* Trust bit 28 up to Penryn, I could not find any
 194                           documentation on that; if you happen to know
 195                           someone at Intel please ask */
 196                        usemsr_ee = 0;
 197                } else {
 198                        /* Platform ID bits 52:50 (EDX starts at bit 32) */
 199                        platform_id = (edx >> 18) & 0x7;
 200
 201                        /* Mobile Penryn CPU seems to be platform ID 7 or 5
 202                          (guesswork) */
 203                        if ((c->x86_model == 0x17) &&
 204                            ((platform_id == 5) || (platform_id == 7))) {
 205                                /* If MSR EE bit is set, set it to 90 degrees C,
 206                                   otherwise 105 degrees C */
 207                                tjmax_ee = 90000;
 208                                tjmax = 105000;
 209                        }
 210                }
 211        }
 212
 213        if (usemsr_ee) {
 214
 215                err = rdmsr_safe_on_cpu(id, 0xee, &eax, &edx);
 216                if (err) {
 217                        dev_warn(dev,
 218                                 "Unable to access MSR 0xEE, for Tjmax, left"
 219                                 " at default");
 220                } else if (eax & 0x40000000) {
 221                        tjmax = tjmax_ee;
 222                }
 223        /* if we dont use msr EE it means we are desktop CPU (with exeception
 224           of Atom) */
 225        } else if (tjmax == 100000) {
 226                dev_warn(dev, "Using relative temperature scale!\n");
 227        }
 228
 229        return tjmax;
 230}
 231
 232static int __devinit coretemp_probe(struct platform_device *pdev)
 233{
 234        struct coretemp_data *data;
 235        struct cpuinfo_x86 *c = &cpu_data(pdev->id);
 236        int err;
 237        u32 eax, edx;
 238
 239        if (!(data = kzalloc(sizeof(struct coretemp_data), GFP_KERNEL))) {
 240                err = -ENOMEM;
 241                dev_err(&pdev->dev, "Out of memory\n");
 242                goto exit;
 243        }
 244
 245        data->id = pdev->id;
 246        data->name = "coretemp";
 247        mutex_init(&data->update_lock);
 248
 249        /* test if we can access the THERM_STATUS MSR */
 250        err = rdmsr_safe_on_cpu(data->id, MSR_IA32_THERM_STATUS, &eax, &edx);
 251        if (err) {
 252                dev_err(&pdev->dev,
 253                        "Unable to access THERM_STATUS MSR, giving up\n");
 254                goto exit_free;
 255        }
 256
 257        /* Check if we have problem with errata AE18 of Core processors:
 258           Readings might stop update when processor visited too deep sleep,
 259           fixed for stepping D0 (6EC).
 260        */
 261
 262        if ((c->x86_model == 0xe) && (c->x86_mask < 0xc)) {
 263                /* check for microcode update */
 264                rdmsr_on_cpu(data->id, MSR_IA32_UCODE_REV, &eax, &edx);
 265                if (edx < 0x39) {
 266                        err = -ENODEV;
 267                        dev_err(&pdev->dev,
 268                                "Errata AE18 not fixed, update BIOS or "
 269                                "microcode of the CPU!\n");
 270                        goto exit_free;
 271                }
 272        }
 273
 274        data->tjmax = adjust_tjmax(c, data->id, &pdev->dev);
 275        platform_set_drvdata(pdev, data);
 276
 277        /* read the still undocumented IA32_TEMPERATURE_TARGET it exists
 278           on older CPUs but not in this register, Atoms don't have it either */
 279
 280        if ((c->x86_model > 0xe) && (c->x86_model != 0x1c)) {
 281                err = rdmsr_safe_on_cpu(data->id, 0x1a2, &eax, &edx);
 282                if (err) {
 283                        dev_warn(&pdev->dev, "Unable to read"
 284                                        " IA32_TEMPERATURE_TARGET MSR\n");
 285                } else {
 286                        data->ttarget = data->tjmax -
 287                                        (((eax >> 8) & 0xff) * 1000);
 288                        err = device_create_file(&pdev->dev,
 289                                        &sensor_dev_attr_temp1_max.dev_attr);
 290                        if (err)
 291                                goto exit_free;
 292                }
 293        }
 294
 295        if ((err = sysfs_create_group(&pdev->dev.kobj, &coretemp_group)))
 296                goto exit_dev;
 297
 298        data->hwmon_dev = hwmon_device_register(&pdev->dev);
 299        if (IS_ERR(data->hwmon_dev)) {
 300                err = PTR_ERR(data->hwmon_dev);
 301                dev_err(&pdev->dev, "Class registration failed (%d)\n",
 302                        err);
 303                goto exit_class;
 304        }
 305
 306        return 0;
 307
 308exit_class:
 309        sysfs_remove_group(&pdev->dev.kobj, &coretemp_group);
 310exit_dev:
 311        device_remove_file(&pdev->dev, &sensor_dev_attr_temp1_max.dev_attr);
 312exit_free:
 313        kfree(data);
 314exit:
 315        return err;
 316}
 317
 318static int __devexit coretemp_remove(struct platform_device *pdev)
 319{
 320        struct coretemp_data *data = platform_get_drvdata(pdev);
 321
 322        hwmon_device_unregister(data->hwmon_dev);
 323        sysfs_remove_group(&pdev->dev.kobj, &coretemp_group);
 324        device_remove_file(&pdev->dev, &sensor_dev_attr_temp1_max.dev_attr);
 325        platform_set_drvdata(pdev, NULL);
 326        kfree(data);
 327        return 0;
 328}
 329
 330static struct platform_driver coretemp_driver = {
 331        .driver = {
 332                .owner = THIS_MODULE,
 333                .name = DRVNAME,
 334        },
 335        .probe = coretemp_probe,
 336        .remove = __devexit_p(coretemp_remove),
 337};
 338
 339struct pdev_entry {
 340        struct list_head list;
 341        struct platform_device *pdev;
 342        unsigned int cpu;
 343};
 344
 345static LIST_HEAD(pdev_list);
 346static DEFINE_MUTEX(pdev_list_mutex);
 347
 348static int __cpuinit coretemp_device_add(unsigned int cpu)
 349{
 350        int err;
 351        struct platform_device *pdev;
 352        struct pdev_entry *pdev_entry;
 353
 354        pdev = platform_device_alloc(DRVNAME, cpu);
 355        if (!pdev) {
 356                err = -ENOMEM;
 357                printk(KERN_ERR DRVNAME ": Device allocation failed\n");
 358                goto exit;
 359        }
 360
 361        pdev_entry = kzalloc(sizeof(struct pdev_entry), GFP_KERNEL);
 362        if (!pdev_entry) {
 363                err = -ENOMEM;
 364                goto exit_device_put;
 365        }
 366
 367        err = platform_device_add(pdev);
 368        if (err) {
 369                printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n",
 370                       err);
 371                goto exit_device_free;
 372        }
 373
 374        pdev_entry->pdev = pdev;
 375        pdev_entry->cpu = cpu;
 376        mutex_lock(&pdev_list_mutex);
 377        list_add_tail(&pdev_entry->list, &pdev_list);
 378        mutex_unlock(&pdev_list_mutex);
 379
 380        return 0;
 381
 382exit_device_free:
 383        kfree(pdev_entry);
 384exit_device_put:
 385        platform_device_put(pdev);
 386exit:
 387        return err;
 388}
 389
 390#ifdef CONFIG_HOTPLUG_CPU
 391static void coretemp_device_remove(unsigned int cpu)
 392{
 393        struct pdev_entry *p, *n;
 394        mutex_lock(&pdev_list_mutex);
 395        list_for_each_entry_safe(p, n, &pdev_list, list) {
 396                if (p->cpu == cpu) {
 397                        platform_device_unregister(p->pdev);
 398                        list_del(&p->list);
 399                        kfree(p);
 400                }
 401        }
 402        mutex_unlock(&pdev_list_mutex);
 403}
 404
 405static int __cpuinit coretemp_cpu_callback(struct notifier_block *nfb,
 406                                 unsigned long action, void *hcpu)
 407{
 408        unsigned int cpu = (unsigned long) hcpu;
 409
 410        switch (action) {
 411        case CPU_ONLINE:
 412        case CPU_DOWN_FAILED:
 413                coretemp_device_add(cpu);
 414                break;
 415        case CPU_DOWN_PREPARE:
 416                coretemp_device_remove(cpu);
 417                break;
 418        }
 419        return NOTIFY_OK;
 420}
 421
 422static struct notifier_block coretemp_cpu_notifier __refdata = {
 423        .notifier_call = coretemp_cpu_callback,
 424};
 425#endif                          /* !CONFIG_HOTPLUG_CPU */
 426
 427static int __init coretemp_init(void)
 428{
 429        int i, err = -ENODEV;
 430        struct pdev_entry *p, *n;
 431
 432        /* quick check if we run Intel */
 433        if (cpu_data(0).x86_vendor != X86_VENDOR_INTEL)
 434                goto exit;
 435
 436        err = platform_driver_register(&coretemp_driver);
 437        if (err)
 438                goto exit;
 439
 440        for_each_online_cpu(i) {
 441                struct cpuinfo_x86 *c = &cpu_data(i);
 442
 443                /* check if family 6, models 0xe (Pentium M DC),
 444                  0xf (Core 2 DC 65nm), 0x16 (Core 2 SC 65nm),
 445                  0x17 (Penryn 45nm), 0x1a (Nehalem), 0x1c (Atom),
 446                  0x1e (Lynnfield) */
 447                if ((c->cpuid_level < 0) || (c->x86 != 0x6) ||
 448                    !((c->x86_model == 0xe) || (c->x86_model == 0xf) ||
 449                        (c->x86_model == 0x16) || (c->x86_model == 0x17) ||
 450                        (c->x86_model == 0x1a) || (c->x86_model == 0x1c) ||
 451                        (c->x86_model == 0x1e))) {
 452
 453                        /* supported CPU not found, but report the unknown
 454                           family 6 CPU */
 455                        if ((c->x86 == 0x6) && (c->x86_model > 0xf))
 456                                printk(KERN_WARNING DRVNAME ": Unknown CPU "
 457                                        "model %x\n", c->x86_model);
 458                        continue;
 459                }
 460
 461                err = coretemp_device_add(i);
 462                if (err)
 463                        goto exit_devices_unreg;
 464        }
 465        if (list_empty(&pdev_list)) {
 466                err = -ENODEV;
 467                goto exit_driver_unreg;
 468        }
 469
 470#ifdef CONFIG_HOTPLUG_CPU
 471        register_hotcpu_notifier(&coretemp_cpu_notifier);
 472#endif
 473        return 0;
 474
 475exit_devices_unreg:
 476        mutex_lock(&pdev_list_mutex);
 477        list_for_each_entry_safe(p, n, &pdev_list, list) {
 478                platform_device_unregister(p->pdev);
 479                list_del(&p->list);
 480                kfree(p);
 481        }
 482        mutex_unlock(&pdev_list_mutex);
 483exit_driver_unreg:
 484        platform_driver_unregister(&coretemp_driver);
 485exit:
 486        return err;
 487}
 488
 489static void __exit coretemp_exit(void)
 490{
 491        struct pdev_entry *p, *n;
 492#ifdef CONFIG_HOTPLUG_CPU
 493        unregister_hotcpu_notifier(&coretemp_cpu_notifier);
 494#endif
 495        mutex_lock(&pdev_list_mutex);
 496        list_for_each_entry_safe(p, n, &pdev_list, list) {
 497                platform_device_unregister(p->pdev);
 498                list_del(&p->list);
 499                kfree(p);
 500        }
 501        mutex_unlock(&pdev_list_mutex);
 502        platform_driver_unregister(&coretemp_driver);
 503}
 504
 505MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
 506MODULE_DESCRIPTION("Intel Core temperature monitor");
 507MODULE_LICENSE("GPL");
 508
 509module_init(coretemp_init)
 510module_exit(coretemp_exit)
 511