linux/drivers/hwmon/via-cputemp.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * via-cputemp.c - Driver for VIA CPU core temperature monitoring
   4 * Copyright (C) 2009 VIA Technologies, Inc.
   5 *
   6 * based on existing coretemp.c, which is
   7 *
   8 * Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
   9 */
  10
  11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13#include <linux/module.h>
  14#include <linux/init.h>
  15#include <linux/slab.h>
  16#include <linux/hwmon.h>
  17#include <linux/hwmon-vid.h>
  18#include <linux/sysfs.h>
  19#include <linux/hwmon-sysfs.h>
  20#include <linux/err.h>
  21#include <linux/mutex.h>
  22#include <linux/list.h>
  23#include <linux/platform_device.h>
  24#include <linux/cpu.h>
  25#include <asm/msr.h>
  26#include <asm/processor.h>
  27#include <asm/cpu_device_id.h>
  28
  29#define DRVNAME "via_cputemp"
  30
  31enum { SHOW_TEMP, SHOW_LABEL, SHOW_NAME };
  32
  33/*
  34 * Functions declaration
  35 */
  36
  37struct via_cputemp_data {
  38        struct device *hwmon_dev;
  39        const char *name;
  40        u8 vrm;
  41        u32 id;
  42        u32 msr_temp;
  43        u32 msr_vid;
  44};
  45
  46/*
  47 * Sysfs stuff
  48 */
  49
  50static ssize_t name_show(struct device *dev, struct device_attribute *devattr,
  51                         char *buf)
  52{
  53        int ret;
  54        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  55        struct via_cputemp_data *data = dev_get_drvdata(dev);
  56
  57        if (attr->index == SHOW_NAME)
  58                ret = sprintf(buf, "%s\n", data->name);
  59        else    /* show label */
  60                ret = sprintf(buf, "Core %d\n", data->id);
  61        return ret;
  62}
  63
  64static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
  65                         char *buf)
  66{
  67        struct via_cputemp_data *data = dev_get_drvdata(dev);
  68        u32 eax, edx;
  69        int err;
  70
  71        err = rdmsr_safe_on_cpu(data->id, data->msr_temp, &eax, &edx);
  72        if (err)
  73                return -EAGAIN;
  74
  75        return sprintf(buf, "%lu\n", ((unsigned long)eax & 0xffffff) * 1000);
  76}
  77
  78static ssize_t cpu0_vid_show(struct device *dev,
  79                             struct device_attribute *devattr, char *buf)
  80{
  81        struct via_cputemp_data *data = dev_get_drvdata(dev);
  82        u32 eax, edx;
  83        int err;
  84
  85        err = rdmsr_safe_on_cpu(data->id, data->msr_vid, &eax, &edx);
  86        if (err)
  87                return -EAGAIN;
  88
  89        return sprintf(buf, "%d\n", vid_from_reg(~edx & 0x7f, data->vrm));
  90}
  91
  92static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, SHOW_TEMP);
  93static SENSOR_DEVICE_ATTR_RO(temp1_label, name, SHOW_LABEL);
  94static SENSOR_DEVICE_ATTR_RO(name, name, SHOW_NAME);
  95
  96static struct attribute *via_cputemp_attributes[] = {
  97        &sensor_dev_attr_name.dev_attr.attr,
  98        &sensor_dev_attr_temp1_label.dev_attr.attr,
  99        &sensor_dev_attr_temp1_input.dev_attr.attr,
 100        NULL
 101};
 102
 103static const struct attribute_group via_cputemp_group = {
 104        .attrs = via_cputemp_attributes,
 105};
 106
 107/* Optional attributes */
 108static DEVICE_ATTR_RO(cpu0_vid);
 109
 110static int via_cputemp_probe(struct platform_device *pdev)
 111{
 112        struct via_cputemp_data *data;
 113        struct cpuinfo_x86 *c = &cpu_data(pdev->id);
 114        int err;
 115        u32 eax, edx;
 116
 117        data = devm_kzalloc(&pdev->dev, sizeof(struct via_cputemp_data),
 118                            GFP_KERNEL);
 119        if (!data)
 120                return -ENOMEM;
 121
 122        data->id = pdev->id;
 123        data->name = "via_cputemp";
 124
 125        if (c->x86 == 7) {
 126                data->msr_temp = 0x1423;
 127        } else {
 128                switch (c->x86_model) {
 129                case 0xA:
 130                        /* C7 A */
 131                case 0xD:
 132                        /* C7 D */
 133                        data->msr_temp = 0x1169;
 134                        data->msr_vid = 0x198;
 135                        break;
 136                case 0xF:
 137                        /* Nano */
 138                        data->msr_temp = 0x1423;
 139                        break;
 140                default:
 141                        return -ENODEV;
 142                }
 143        }
 144
 145        /* test if we can access the TEMPERATURE MSR */
 146        err = rdmsr_safe_on_cpu(data->id, data->msr_temp, &eax, &edx);
 147        if (err) {
 148                dev_err(&pdev->dev,
 149                        "Unable to access TEMPERATURE MSR, giving up\n");
 150                return err;
 151        }
 152
 153        platform_set_drvdata(pdev, data);
 154
 155        err = sysfs_create_group(&pdev->dev.kobj, &via_cputemp_group);
 156        if (err)
 157                return err;
 158
 159        if (data->msr_vid)
 160                data->vrm = vid_which_vrm();
 161
 162        if (data->vrm) {
 163                err = device_create_file(&pdev->dev, &dev_attr_cpu0_vid);
 164                if (err)
 165                        goto exit_remove;
 166        }
 167
 168        data->hwmon_dev = hwmon_device_register(&pdev->dev);
 169        if (IS_ERR(data->hwmon_dev)) {
 170                err = PTR_ERR(data->hwmon_dev);
 171                dev_err(&pdev->dev, "Class registration failed (%d)\n",
 172                        err);
 173                goto exit_remove;
 174        }
 175
 176        return 0;
 177
 178exit_remove:
 179        if (data->vrm)
 180                device_remove_file(&pdev->dev, &dev_attr_cpu0_vid);
 181        sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
 182        return err;
 183}
 184
 185static int via_cputemp_remove(struct platform_device *pdev)
 186{
 187        struct via_cputemp_data *data = platform_get_drvdata(pdev);
 188
 189        hwmon_device_unregister(data->hwmon_dev);
 190        if (data->vrm)
 191                device_remove_file(&pdev->dev, &dev_attr_cpu0_vid);
 192        sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
 193        return 0;
 194}
 195
 196static struct platform_driver via_cputemp_driver = {
 197        .driver = {
 198                .name = DRVNAME,
 199        },
 200        .probe = via_cputemp_probe,
 201        .remove = via_cputemp_remove,
 202};
 203
 204struct pdev_entry {
 205        struct list_head list;
 206        struct platform_device *pdev;
 207        unsigned int cpu;
 208};
 209
 210static LIST_HEAD(pdev_list);
 211static DEFINE_MUTEX(pdev_list_mutex);
 212
 213static int via_cputemp_online(unsigned int cpu)
 214{
 215        int err;
 216        struct platform_device *pdev;
 217        struct pdev_entry *pdev_entry;
 218
 219        pdev = platform_device_alloc(DRVNAME, cpu);
 220        if (!pdev) {
 221                err = -ENOMEM;
 222                pr_err("Device allocation failed\n");
 223                goto exit;
 224        }
 225
 226        pdev_entry = kzalloc(sizeof(struct pdev_entry), GFP_KERNEL);
 227        if (!pdev_entry) {
 228                err = -ENOMEM;
 229                goto exit_device_put;
 230        }
 231
 232        err = platform_device_add(pdev);
 233        if (err) {
 234                pr_err("Device addition failed (%d)\n", err);
 235                goto exit_device_free;
 236        }
 237
 238        pdev_entry->pdev = pdev;
 239        pdev_entry->cpu = cpu;
 240        mutex_lock(&pdev_list_mutex);
 241        list_add_tail(&pdev_entry->list, &pdev_list);
 242        mutex_unlock(&pdev_list_mutex);
 243
 244        return 0;
 245
 246exit_device_free:
 247        kfree(pdev_entry);
 248exit_device_put:
 249        platform_device_put(pdev);
 250exit:
 251        return err;
 252}
 253
 254static int via_cputemp_down_prep(unsigned int cpu)
 255{
 256        struct pdev_entry *p;
 257
 258        mutex_lock(&pdev_list_mutex);
 259        list_for_each_entry(p, &pdev_list, list) {
 260                if (p->cpu == cpu) {
 261                        platform_device_unregister(p->pdev);
 262                        list_del(&p->list);
 263                        mutex_unlock(&pdev_list_mutex);
 264                        kfree(p);
 265                        return 0;
 266                }
 267        }
 268        mutex_unlock(&pdev_list_mutex);
 269        return 0;
 270}
 271
 272static const struct x86_cpu_id __initconst cputemp_ids[] = {
 273        X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 6, X86_CENTAUR_FAM6_C7_A,   NULL),
 274        X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 6, X86_CENTAUR_FAM6_C7_D,   NULL),
 275        X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 6, X86_CENTAUR_FAM6_NANO,   NULL),
 276        X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 7, X86_MODEL_ANY,           NULL),
 277        {}
 278};
 279MODULE_DEVICE_TABLE(x86cpu, cputemp_ids);
 280
 281static enum cpuhp_state via_temp_online;
 282
 283static int __init via_cputemp_init(void)
 284{
 285        int err;
 286
 287        if (!x86_match_cpu(cputemp_ids))
 288                return -ENODEV;
 289
 290        err = platform_driver_register(&via_cputemp_driver);
 291        if (err)
 292                goto exit;
 293
 294        err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/via:online",
 295                                via_cputemp_online, via_cputemp_down_prep);
 296        if (err < 0)
 297                goto exit_driver_unreg;
 298        via_temp_online = err;
 299
 300#ifndef CONFIG_HOTPLUG_CPU
 301        if (list_empty(&pdev_list)) {
 302                err = -ENODEV;
 303                goto exit_hp_unreg;
 304        }
 305#endif
 306        return 0;
 307
 308#ifndef CONFIG_HOTPLUG_CPU
 309exit_hp_unreg:
 310        cpuhp_remove_state_nocalls(via_temp_online);
 311#endif
 312exit_driver_unreg:
 313        platform_driver_unregister(&via_cputemp_driver);
 314exit:
 315        return err;
 316}
 317
 318static void __exit via_cputemp_exit(void)
 319{
 320        cpuhp_remove_state(via_temp_online);
 321        platform_driver_unregister(&via_cputemp_driver);
 322}
 323
 324MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
 325MODULE_DESCRIPTION("VIA CPU temperature monitor");
 326MODULE_LICENSE("GPL");
 327
 328module_init(via_cputemp_init)
 329module_exit(via_cputemp_exit)
 330