1/*
2 * via-cputemp.c - Driver for VIA CPU core temperature monitoring
3 * Copyright (C) 2009 VIA Technologies, Inc.
4 *
5 * based on existing coretemp.c, which is
6 *
7 * Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; version 2 of the License.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 * 02110-1301 USA.
22 */
23
24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/module.h>
27#include <linux/init.h>
28#include <linux/slab.h>
29#include <linux/hwmon.h>
30#include <linux/hwmon-vid.h>
31#include <linux/sysfs.h>
32#include <linux/hwmon-sysfs.h>
33#include <linux/err.h>
34#include <linux/mutex.h>
35#include <linux/list.h>
36#include <linux/platform_device.h>
37#include <linux/cpu.h>
38#include <asm/msr.h>
39#include <asm/processor.h>
40#include <asm/cpu_device_id.h>
41
42#define DRVNAME	"via_cputemp"
43
44enum { SHOW_TEMP, SHOW_LABEL, SHOW_NAME };
45
46/*
47 * Functions declaration
48 */
49
50struct via_cputemp_data {
51	struct device *hwmon_dev;
52	const char *name;
53	u8 vrm;
54	u32 id;
55	u32 msr_temp;
56	u32 msr_vid;
57};
58
59/*
60 * Sysfs stuff
61 */
62
63static ssize_t show_name(struct device *dev, struct device_attribute
64			  *devattr, char *buf)
65{
66	int ret;
67	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
68	struct via_cputemp_data *data = dev_get_drvdata(dev);
69
70	if (attr->index == SHOW_NAME)
71		ret = sprintf(buf, "%s\n", data->name);
72	else	/* show label */
73		ret = sprintf(buf, "Core %d\n", data->id);
74	return ret;
75}
76
77static ssize_t show_temp(struct device *dev,
78			 struct device_attribute *devattr, char *buf)
79{
80	struct via_cputemp_data *data = dev_get_drvdata(dev);
81	u32 eax, edx;
82	int err;
83
84	err = rdmsr_safe_on_cpu(data->id, data->msr_temp, &eax, &edx);
85	if (err)
86		return -EAGAIN;
87
88	return sprintf(buf, "%lu\n", ((unsigned long)eax & 0xffffff) * 1000);
89}
90
91static ssize_t show_cpu_vid(struct device *dev,
92			    struct device_attribute *devattr, char *buf)
93{
94	struct via_cputemp_data *data = dev_get_drvdata(dev);
95	u32 eax, edx;
96	int err;
97
98	err = rdmsr_safe_on_cpu(data->id, data->msr_vid, &eax, &edx);
99	if (err)
100		return -EAGAIN;
101
102	return sprintf(buf, "%d\n", vid_from_reg(~edx & 0x7f, data->vrm));
103}
104
105static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL,
106			  SHOW_TEMP);
107static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_name, NULL, SHOW_LABEL);
108static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, SHOW_NAME);
109
110static struct attribute *via_cputemp_attributes[] = {
111	&sensor_dev_attr_name.dev_attr.attr,
112	&sensor_dev_attr_temp1_label.dev_attr.attr,
113	&sensor_dev_attr_temp1_input.dev_attr.attr,
114	NULL
115};
116
117static const struct attribute_group via_cputemp_group = {
118	.attrs = via_cputemp_attributes,
119};
120
121/* Optional attributes */
122static DEVICE_ATTR(cpu0_vid, S_IRUGO, show_cpu_vid, NULL);
123
124static int via_cputemp_probe(struct platform_device *pdev)
125{
126	struct via_cputemp_data *data;
127	struct cpuinfo_x86 *c = &cpu_data(pdev->id);
128	int err;
129	u32 eax, edx;
130
131	data = devm_kzalloc(&pdev->dev, sizeof(struct via_cputemp_data),
132			    GFP_KERNEL);
133	if (!data)
134		return -ENOMEM;
135
136	data->id = pdev->id;
137	data->name = "via_cputemp";
138
139	switch (c->x86_model) {
140	case 0xA:
141		/* C7 A */
142	case 0xD:
143		/* C7 D */
144		data->msr_temp = 0x1169;
145		data->msr_vid = 0x198;
146		break;
147	case 0xF:
148		/* Nano */
149		data->msr_temp = 0x1423;
150		break;
151	default:
152		return -ENODEV;
153	}
154
155	/* test if we can access the TEMPERATURE MSR */
156	err = rdmsr_safe_on_cpu(data->id, data->msr_temp, &eax, &edx);
157	if (err) {
158		dev_err(&pdev->dev,
159			"Unable to access TEMPERATURE MSR, giving up\n");
160		return err;
161	}
162
163	platform_set_drvdata(pdev, data);
164
165	err = sysfs_create_group(&pdev->dev.kobj, &via_cputemp_group);
166	if (err)
167		return err;
168
169	if (data->msr_vid)
170		data->vrm = vid_which_vrm();
171
172	if (data->vrm) {
173		err = device_create_file(&pdev->dev, &dev_attr_cpu0_vid);
174		if (err)
175			goto exit_remove;
176	}
177
178	data->hwmon_dev = hwmon_device_register(&pdev->dev);
179	if (IS_ERR(data->hwmon_dev)) {
180		err = PTR_ERR(data->hwmon_dev);
181		dev_err(&pdev->dev, "Class registration failed (%d)\n",
182			err);
183		goto exit_remove;
184	}
185
186	return 0;
187
188exit_remove:
189	if (data->vrm)
190		device_remove_file(&pdev->dev, &dev_attr_cpu0_vid);
191	sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
192	return err;
193}
194
195static int via_cputemp_remove(struct platform_device *pdev)
196{
197	struct via_cputemp_data *data = platform_get_drvdata(pdev);
198
199	hwmon_device_unregister(data->hwmon_dev);
200	if (data->vrm)
201		device_remove_file(&pdev->dev, &dev_attr_cpu0_vid);
202	sysfs_remove_group(&pdev->dev.kobj, &via_cputemp_group);
203	return 0;
204}
205
206static struct platform_driver via_cputemp_driver = {
207	.driver = {
208		.name = DRVNAME,
209	},
210	.probe = via_cputemp_probe,
211	.remove = via_cputemp_remove,
212};
213
214struct pdev_entry {
215	struct list_head list;
216	struct platform_device *pdev;
217	unsigned int cpu;
218};
219
220static LIST_HEAD(pdev_list);
221static DEFINE_MUTEX(pdev_list_mutex);
222
223static int via_cputemp_device_add(unsigned int cpu)
224{
225	int err;
226	struct platform_device *pdev;
227	struct pdev_entry *pdev_entry;
228
229	pdev = platform_device_alloc(DRVNAME, cpu);
230	if (!pdev) {
231		err = -ENOMEM;
232		pr_err("Device allocation failed\n");
233		goto exit;
234	}
235
236	pdev_entry = kzalloc(sizeof(struct pdev_entry), GFP_KERNEL);
237	if (!pdev_entry) {
238		err = -ENOMEM;
239		goto exit_device_put;
240	}
241
242	err = platform_device_add(pdev);
243	if (err) {
244		pr_err("Device addition failed (%d)\n", err);
245		goto exit_device_free;
246	}
247
248	pdev_entry->pdev = pdev;
249	pdev_entry->cpu = cpu;
250	mutex_lock(&pdev_list_mutex);
251	list_add_tail(&pdev_entry->list, &pdev_list);
252	mutex_unlock(&pdev_list_mutex);
253
254	return 0;
255
256exit_device_free:
257	kfree(pdev_entry);
258exit_device_put:
259	platform_device_put(pdev);
260exit:
261	return err;
262}
263
264static void via_cputemp_device_remove(unsigned int cpu)
265{
266	struct pdev_entry *p;
267
268	mutex_lock(&pdev_list_mutex);
269	list_for_each_entry(p, &pdev_list, list) {
270		if (p->cpu == cpu) {
271			platform_device_unregister(p->pdev);
272			list_del(&p->list);
273			mutex_unlock(&pdev_list_mutex);
274			kfree(p);
275			return;
276		}
277	}
278	mutex_unlock(&pdev_list_mutex);
279}
280
281static int via_cputemp_cpu_callback(struct notifier_block *nfb,
282				    unsigned long action, void *hcpu)
283{
284	unsigned int cpu = (unsigned long) hcpu;
285
286	switch (action) {
287	case CPU_ONLINE:
288	case CPU_DOWN_FAILED:
289		via_cputemp_device_add(cpu);
290		break;
291	case CPU_DOWN_PREPARE:
292		via_cputemp_device_remove(cpu);
293		break;
294	}
295	return NOTIFY_OK;
296}
297
298static struct notifier_block via_cputemp_cpu_notifier __refdata = {
299	.notifier_call = via_cputemp_cpu_callback,
300};
301
302static const struct x86_cpu_id __initconst cputemp_ids[] = {
303	{ X86_VENDOR_CENTAUR, 6, 0xa, }, /* C7 A */
304	{ X86_VENDOR_CENTAUR, 6, 0xd, }, /* C7 D */
305	{ X86_VENDOR_CENTAUR, 6, 0xf, }, /* Nano */
306	{}
307};
308MODULE_DEVICE_TABLE(x86cpu, cputemp_ids);
309
310static int __init via_cputemp_init(void)
311{
312	int i, err;
313
314	if (!x86_match_cpu(cputemp_ids))
315		return -ENODEV;
316
317	err = platform_driver_register(&via_cputemp_driver);
318	if (err)
319		goto exit;
320
321	cpu_notifier_register_begin();
322	for_each_online_cpu(i) {
323		struct cpuinfo_x86 *c = &cpu_data(i);
324
325		if (c->x86 != 6)
326			continue;
327
328		if (c->x86_model < 0x0a)
329			continue;
330
331		if (c->x86_model > 0x0f) {
332			pr_warn("Unknown CPU model 0x%x\n", c->x86_model);
333			continue;
334		}
335
336		via_cputemp_device_add(i);
337	}
338
339#ifndef CONFIG_HOTPLUG_CPU
340	if (list_empty(&pdev_list)) {
341		cpu_notifier_register_done();
342		err = -ENODEV;
343		goto exit_driver_unreg;
344	}
345#endif
346
347	__register_hotcpu_notifier(&via_cputemp_cpu_notifier);
348	cpu_notifier_register_done();
349	return 0;
350
351#ifndef CONFIG_HOTPLUG_CPU
352exit_driver_unreg:
353	platform_driver_unregister(&via_cputemp_driver);
354#endif
355exit:
356	return err;
357}
358
359static void __exit via_cputemp_exit(void)
360{
361	struct pdev_entry *p, *n;
362
363	cpu_notifier_register_begin();
364	__unregister_hotcpu_notifier(&via_cputemp_cpu_notifier);
365	mutex_lock(&pdev_list_mutex);
366	list_for_each_entry_safe(p, n, &pdev_list, list) {
367		platform_device_unregister(p->pdev);
368		list_del(&p->list);
369		kfree(p);
370	}
371	mutex_unlock(&pdev_list_mutex);
372	cpu_notifier_register_done();
373	platform_driver_unregister(&via_cputemp_driver);
374}
375
376MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
377MODULE_DESCRIPTION("VIA CPU temperature monitor");
378MODULE_LICENSE("GPL");
379
380module_init(via_cputemp_init)
381module_exit(via_cputemp_exit)
382