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
name_show(struct device * dev,struct device_attribute * devattr,char * buf)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
temp_show(struct device * dev,struct device_attribute * devattr,char * buf)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
cpu0_vid_show(struct device * dev,struct device_attribute * devattr,char * buf)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
via_cputemp_probe(struct platform_device * pdev)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
via_cputemp_remove(struct platform_device * pdev)185 static void 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 }
194
195 static struct platform_driver via_cputemp_driver = {
196 .driver = {
197 .name = DRVNAME,
198 },
199 .probe = via_cputemp_probe,
200 .remove_new = via_cputemp_remove,
201 };
202
203 struct pdev_entry {
204 struct list_head list;
205 struct platform_device *pdev;
206 unsigned int cpu;
207 };
208
209 static LIST_HEAD(pdev_list);
210 static DEFINE_MUTEX(pdev_list_mutex);
211
via_cputemp_online(unsigned int cpu)212 static int via_cputemp_online(unsigned int cpu)
213 {
214 int err;
215 struct platform_device *pdev;
216 struct pdev_entry *pdev_entry;
217
218 pdev = platform_device_alloc(DRVNAME, cpu);
219 if (!pdev) {
220 err = -ENOMEM;
221 pr_err("Device allocation failed\n");
222 goto exit;
223 }
224
225 pdev_entry = kzalloc(sizeof(struct pdev_entry), GFP_KERNEL);
226 if (!pdev_entry) {
227 err = -ENOMEM;
228 goto exit_device_put;
229 }
230
231 err = platform_device_add(pdev);
232 if (err) {
233 pr_err("Device addition failed (%d)\n", err);
234 goto exit_device_free;
235 }
236
237 pdev_entry->pdev = pdev;
238 pdev_entry->cpu = cpu;
239 mutex_lock(&pdev_list_mutex);
240 list_add_tail(&pdev_entry->list, &pdev_list);
241 mutex_unlock(&pdev_list_mutex);
242
243 return 0;
244
245 exit_device_free:
246 kfree(pdev_entry);
247 exit_device_put:
248 platform_device_put(pdev);
249 exit:
250 return err;
251 }
252
via_cputemp_down_prep(unsigned int cpu)253 static int via_cputemp_down_prep(unsigned int cpu)
254 {
255 struct pdev_entry *p;
256
257 mutex_lock(&pdev_list_mutex);
258 list_for_each_entry(p, &pdev_list, list) {
259 if (p->cpu == cpu) {
260 platform_device_unregister(p->pdev);
261 list_del(&p->list);
262 mutex_unlock(&pdev_list_mutex);
263 kfree(p);
264 return 0;
265 }
266 }
267 mutex_unlock(&pdev_list_mutex);
268 return 0;
269 }
270
271 static const struct x86_cpu_id __initconst cputemp_ids[] = {
272 X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 6, X86_CENTAUR_FAM6_C7_A, NULL),
273 X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 6, X86_CENTAUR_FAM6_C7_D, NULL),
274 X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 6, X86_CENTAUR_FAM6_NANO, NULL),
275 X86_MATCH_VENDOR_FAM_MODEL(CENTAUR, 7, X86_MODEL_ANY, NULL),
276 {}
277 };
278 MODULE_DEVICE_TABLE(x86cpu, cputemp_ids);
279
280 static enum cpuhp_state via_temp_online;
281
via_cputemp_init(void)282 static int __init via_cputemp_init(void)
283 {
284 int err;
285
286 if (!x86_match_cpu(cputemp_ids))
287 return -ENODEV;
288
289 err = platform_driver_register(&via_cputemp_driver);
290 if (err)
291 goto exit;
292
293 err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/via:online",
294 via_cputemp_online, via_cputemp_down_prep);
295 if (err < 0)
296 goto exit_driver_unreg;
297 via_temp_online = err;
298
299 #ifndef CONFIG_HOTPLUG_CPU
300 if (list_empty(&pdev_list)) {
301 err = -ENODEV;
302 goto exit_hp_unreg;
303 }
304 #endif
305 return 0;
306
307 #ifndef CONFIG_HOTPLUG_CPU
308 exit_hp_unreg:
309 cpuhp_remove_state_nocalls(via_temp_online);
310 #endif
311 exit_driver_unreg:
312 platform_driver_unregister(&via_cputemp_driver);
313 exit:
314 return err;
315 }
316
via_cputemp_exit(void)317 static void __exit via_cputemp_exit(void)
318 {
319 cpuhp_remove_state(via_temp_online);
320 platform_driver_unregister(&via_cputemp_driver);
321 }
322
323 MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
324 MODULE_DESCRIPTION("VIA CPU temperature monitor");
325 MODULE_LICENSE("GPL");
326
327 module_init(via_cputemp_init)
328 module_exit(via_cputemp_exit)
329