1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * k8temp.c - Linux kernel module for hardware monitoring
4 *
5 * Copyright (C) 2006 Rudolf Marek <r.marek@assembler.cz>
6 *
7 * Inspired from the w83785 and amd756 drivers.
8 */
9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/slab.h>
13#include <linux/pci.h>
14#include <linux/hwmon.h>
15#include <linux/err.h>
16#include <linux/mutex.h>
17#include <asm/processor.h>
18
19#define TEMP_FROM_REG(val)	(((((val) >> 16) & 0xff) - 49) * 1000)
20#define REG_TEMP	0xe4
21#define SEL_PLACE	0x40
22#define SEL_CORE	0x04
23
24struct k8temp_data {
25	struct mutex update_lock;
26
27	/* registers values */
28	u8 sensorsp;		/* sensor presence bits - SEL_CORE, SEL_PLACE */
29	u8 swap_core_select;    /* meaning of SEL_CORE is inverted */
30	u32 temp_offset;
31};
32
33static const struct pci_device_id k8temp_ids[] = {
34	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
35	{ 0 },
36};
37MODULE_DEVICE_TABLE(pci, k8temp_ids);
38
39static int is_rev_g_desktop(u8 model)
40{
41	u32 brandidx;
42
43	if (model < 0x69)
44		return 0;
45
46	if (model == 0xc1 || model == 0x6c || model == 0x7c)
47		return 0;
48
49	/*
50	 * Differentiate between AM2 and ASB1.
51	 * See "Constructing the processor Name String" in "Revision
52	 * Guide for AMD NPT Family 0Fh Processors" (33610).
53	 */
54	brandidx = cpuid_ebx(0x80000001);
55	brandidx = (brandidx >> 9) & 0x1f;
56
57	/* Single core */
58	if ((model == 0x6f || model == 0x7f) &&
59	    (brandidx == 0x7 || brandidx == 0x9 || brandidx == 0xc))
60		return 0;
61
62	/* Dual core */
63	if (model == 0x6b &&
64	    (brandidx == 0xb || brandidx == 0xc))
65		return 0;
66
67	return 1;
68}
69
70static umode_t
71k8temp_is_visible(const void *drvdata, enum hwmon_sensor_types type,
72		  u32 attr, int channel)
73{
74	const struct k8temp_data *data = drvdata;
75
76	if ((channel & 1) && !(data->sensorsp & SEL_PLACE))
77		return 0;
78
79	if ((channel & 2) && !(data->sensorsp & SEL_CORE))
80		return 0;
81
82	return 0444;
83}
84
85static int
86k8temp_read(struct device *dev, enum hwmon_sensor_types type,
87	    u32 attr, int channel, long *val)
88{
89	struct k8temp_data *data = dev_get_drvdata(dev);
90	struct pci_dev *pdev = to_pci_dev(dev->parent);
91	int core, place;
92	u32 temp;
93	u8 tmp;
94
95	core = (channel >> 1) & 1;
96	place = channel & 1;
97
98	core ^= data->swap_core_select;
99
100	mutex_lock(&data->update_lock);
101	pci_read_config_byte(pdev, REG_TEMP, &tmp);
102	tmp &= ~(SEL_PLACE | SEL_CORE);
103	if (core)
104		tmp |= SEL_CORE;
105	if (place)
106		tmp |= SEL_PLACE;
107	pci_write_config_byte(pdev, REG_TEMP, tmp);
108	pci_read_config_dword(pdev, REG_TEMP, &temp);
109	mutex_unlock(&data->update_lock);
110
111	*val = TEMP_FROM_REG(temp) + data->temp_offset;
112
113	return 0;
114}
115
116static const struct hwmon_ops k8temp_ops = {
117	.is_visible = k8temp_is_visible,
118	.read = k8temp_read,
119};
120
121static const struct hwmon_channel_info * const k8temp_info[] = {
122	HWMON_CHANNEL_INFO(temp,
123		HWMON_T_INPUT, HWMON_T_INPUT, HWMON_T_INPUT, HWMON_T_INPUT),
124	NULL
125};
126
127static const struct hwmon_chip_info k8temp_chip_info = {
128	.ops = &k8temp_ops,
129	.info = k8temp_info,
130};
131
132static int k8temp_probe(struct pci_dev *pdev,
133				  const struct pci_device_id *id)
134{
135	u8 scfg;
136	u32 temp;
137	u8 model, stepping;
138	struct k8temp_data *data;
139	struct device *hwmon_dev;
140
141	data = devm_kzalloc(&pdev->dev, sizeof(struct k8temp_data), GFP_KERNEL);
142	if (!data)
143		return -ENOMEM;
144
145	model = boot_cpu_data.x86_model;
146	stepping = boot_cpu_data.x86_stepping;
147
148	/* feature available since SH-C0, exclude older revisions */
149	if ((model == 4 && stepping == 0) ||
150	    (model == 5 && stepping <= 1))
151		return -ENODEV;
152
153	/*
154	 * AMD NPT family 0fh, i.e. RevF and RevG:
155	 * meaning of SEL_CORE bit is inverted
156	 */
157	if (model >= 0x40) {
158		data->swap_core_select = 1;
159		dev_warn(&pdev->dev,
160			 "Temperature readouts might be wrong - check erratum #141\n");
161	}
162
163	/*
164	 * RevG desktop CPUs (i.e. no socket S1G1 or ASB1 parts) need
165	 * additional offset, otherwise reported temperature is below
166	 * ambient temperature
167	 */
168	if (is_rev_g_desktop(model))
169		data->temp_offset = 21000;
170
171	pci_read_config_byte(pdev, REG_TEMP, &scfg);
172	scfg &= ~(SEL_PLACE | SEL_CORE);	/* Select sensor 0, core0 */
173	pci_write_config_byte(pdev, REG_TEMP, scfg);
174	pci_read_config_byte(pdev, REG_TEMP, &scfg);
175
176	if (scfg & (SEL_PLACE | SEL_CORE)) {
177		dev_err(&pdev->dev, "Configuration bit(s) stuck at 1!\n");
178		return -ENODEV;
179	}
180
181	scfg |= (SEL_PLACE | SEL_CORE);
182	pci_write_config_byte(pdev, REG_TEMP, scfg);
183
184	/* now we know if we can change core and/or sensor */
185	pci_read_config_byte(pdev, REG_TEMP, &data->sensorsp);
186
187	if (data->sensorsp & SEL_PLACE) {
188		scfg &= ~SEL_CORE;	/* Select sensor 1, core0 */
189		pci_write_config_byte(pdev, REG_TEMP, scfg);
190		pci_read_config_dword(pdev, REG_TEMP, &temp);
191		scfg |= SEL_CORE;	/* prepare for next selection */
192		if (!((temp >> 16) & 0xff)) /* if temp is 0 -49C is unlikely */
193			data->sensorsp &= ~SEL_PLACE;
194	}
195
196	if (data->sensorsp & SEL_CORE) {
197		scfg &= ~SEL_PLACE;	/* Select sensor 0, core1 */
198		pci_write_config_byte(pdev, REG_TEMP, scfg);
199		pci_read_config_dword(pdev, REG_TEMP, &temp);
200		if (!((temp >> 16) & 0xff)) /* if temp is 0 -49C is unlikely */
201			data->sensorsp &= ~SEL_CORE;
202	}
203
204	mutex_init(&data->update_lock);
205
206	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
207							 "k8temp",
208							 data,
209							 &k8temp_chip_info,
210							 NULL);
211
212	return PTR_ERR_OR_ZERO(hwmon_dev);
213}
214
215static struct pci_driver k8temp_driver = {
216	.name = "k8temp",
217	.id_table = k8temp_ids,
218	.probe = k8temp_probe,
219};
220
221module_pci_driver(k8temp_driver);
222
223MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
224MODULE_DESCRIPTION("AMD K8 core temperature monitor");
225MODULE_LICENSE("GPL");
226