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