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
24 struct 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
33 static const struct pci_device_id k8temp_ids[] = {
34 { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
35 { 0 },
36 };
37 MODULE_DEVICE_TABLE(pci, k8temp_ids);
38
is_rev_g_desktop(u8 model)39 static 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
70 static umode_t
k8temp_is_visible(const void * drvdata,enum hwmon_sensor_types type,u32 attr,int channel)71 k8temp_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
85 static int
k8temp_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)86 k8temp_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
116 static const struct hwmon_ops k8temp_ops = {
117 .is_visible = k8temp_is_visible,
118 .read = k8temp_read,
119 };
120
121 static 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
127 static const struct hwmon_chip_info k8temp_chip_info = {
128 .ops = &k8temp_ops,
129 .info = k8temp_info,
130 };
131
k8temp_probe(struct pci_dev * pdev,const struct pci_device_id * id)132 static 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
215 static struct pci_driver k8temp_driver = {
216 .name = "k8temp",
217 .id_table = k8temp_ids,
218 .probe = k8temp_probe,
219 };
220
221 module_pci_driver(k8temp_driver);
222
223 MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
224 MODULE_DESCRIPTION("AMD K8 core temperature monitor");
225 MODULE_LICENSE("GPL");
226
