drivers/hwmon/via-cputemp.c

   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
  31 enum { SHOW_TEMP, SHOW_LABEL, SHOW_NAME };
  32
  33 /*
  34  * Functions declaration
  35  */
  36
  37 struct 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
  50 static 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
  64 static 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
  78 static 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
  92 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, SHOW_TEMP);
  93 static SENSOR_DEVICE_ATTR_RO(temp1_label, name, SHOW_LABEL);
  94 static SENSOR_DEVICE_ATTR_RO(name, name, SHOW_NAME);
  95
  96 static 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
 103 static const struct attribute_group via_cputemp_group = {
 104         .attrs = via_cputemp_attributes,
 105 };
 106
 107 /* Optional attributes */
 108 static DEVICE_ATTR_RO(cpu0_vid);
 109
 110 static 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
 178 exit_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
 185 static 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
 196 static struct platform_driver via_cputemp_driver = {
 197         .driver = {
 198                 .name = DRVNAME,
 199         },
 200         .probe = via_cputemp_probe,
 201         .remove = via_cputemp_remove,
 202 };
 203
 204 struct pdev_entry {
 205         struct list_head list;
 206         struct platform_device *pdev;
 207         unsigned int cpu;
 208 };
 209
 210 static LIST_HEAD(pdev_list);
 211 static DEFINE_MUTEX(pdev_list_mutex);
 212
 213 static 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
 246 exit_device_free:
 247         kfree(pdev_entry);
 248 exit_device_put:
 249         platform_device_put(pdev);
 250 exit:
 251         return err;
 252 }
 253
 254 static 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
 272 static const struct x86_cpu_id __initconst cputemp_ids[] = {
 273         { X86_VENDOR_CENTAUR, 6, 0xa, }, /* C7 A */
 274         { X86_VENDOR_CENTAUR, 6, 0xd, }, /* C7 D */
 275         { X86_VENDOR_CENTAUR, 6, 0xf, }, /* Nano */
 276         { X86_VENDOR_CENTAUR, 7, X86_MODEL_ANY, },
 277         {}
 278 };
 279 MODULE_DEVICE_TABLE(x86cpu, cputemp_ids);
 280
 281 static enum cpuhp_state via_temp_online;
 282
 283 static 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
 309 exit_hp_unreg:
 310         cpuhp_remove_state_nocalls(via_temp_online);
 311 #endif
 312 exit_driver_unreg:
 313         platform_driver_unregister(&via_cputemp_driver);
 314 exit:
 315         return err;
 316 }
 317
 318 static void __exit via_cputemp_exit(void)
 319 {
 320         cpuhp_remove_state(via_temp_online);
 321         platform_driver_unregister(&via_cputemp_driver);
 322 }
 323
 324 MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
 325 MODULE_DESCRIPTION("VIA CPU temperature monitor");
 326 MODULE_LICENSE("GPL");
 327
 328 module_init(via_cputemp_init)
 329 module_exit(via_cputemp_exit)