1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (C) 2020 Advanced Micro Devices, Inc.
6 #include <asm/cpu_device_id.h>
8 #include <linux/bits.h>
10 #include <linux/cpumask.h>
11 #include <linux/delay.h>
12 #include <linux/device.h>
13 #include <linux/hwmon.h>
14 #include <linux/kernel.h>
15 #include <linux/kthread.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/processor.h>
20 #include <linux/platform_device.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/topology.h>
24 #include <linux/types.h>
26 #define DRVNAME "amd_energy"
28 #define ENERGY_PWR_UNIT_MSR 0xC0010299
29 #define ENERGY_CORE_MSR 0xC001029A
30 #define ENERGY_PKG_MSR 0xC001029B
32 #define AMD_ENERGY_UNIT_MASK 0x01F00
33 #define AMD_ENERGY_MASK 0xFFFFFFFF
35 struct sensor_accumulator {
40 struct amd_energy_data {
41 struct hwmon_channel_info energy_info;
42 const struct hwmon_channel_info *info[2];
43 struct hwmon_chip_info chip;
44 struct task_struct *wrap_accumulate;
45 /* Lock around the accumulator */
47 /* An accumulator for each core and socket */
48 struct sensor_accumulator *accums;
49 unsigned int timeout_ms;
50 /* Energy Status Units */
58 static int amd_energy_read_labels(struct device *dev,
59 enum hwmon_sensor_types type,
60 u32 attr, int channel,
63 struct amd_energy_data *data = dev_get_drvdata(dev);
65 *str = data->label[channel];
69 static void get_energy_units(struct amd_energy_data *data)
73 rdmsrl_safe(ENERGY_PWR_UNIT_MSR, &rapl_units);
74 data->energy_units = (rapl_units & AMD_ENERGY_UNIT_MASK) >> 8;
77 static void accumulate_delta(struct amd_energy_data *data,
78 int channel, int cpu, u32 reg)
80 struct sensor_accumulator *accum;
83 mutex_lock(&data->lock);
84 rdmsrl_safe_on_cpu(cpu, reg, &input);
85 input &= AMD_ENERGY_MASK;
87 accum = &data->accums[channel];
88 if (input >= accum->prev_value)
90 input - accum->prev_value;
92 accum->energy_ctr += UINT_MAX -
93 accum->prev_value + input;
95 accum->prev_value = input;
96 mutex_unlock(&data->lock);
99 static void read_accumulate(struct amd_energy_data *data)
103 for (sock = 0; sock < data->nr_socks; sock++) {
104 scpu = cpumask_first_and(cpu_online_mask,
105 cpumask_of_node(sock));
107 accumulate_delta(data, data->nr_cpus + sock,
108 scpu, ENERGY_PKG_MSR);
111 if (data->core_id >= data->nr_cpus)
116 accumulate_delta(data, cpu, cpu, ENERGY_CORE_MSR);
121 static void amd_add_delta(struct amd_energy_data *data, int ch,
122 int cpu, long *val, u32 reg)
124 struct sensor_accumulator *accum;
127 mutex_lock(&data->lock);
128 rdmsrl_safe_on_cpu(cpu, reg, &input);
129 input &= AMD_ENERGY_MASK;
131 accum = &data->accums[ch];
132 if (input >= accum->prev_value)
133 input += accum->energy_ctr -
136 input += UINT_MAX - accum->prev_value +
139 /* Energy consumed = (1/(2^ESU) * RAW * 1000000UL) μJoules */
140 *val = div64_ul(input * 1000000UL, BIT(data->energy_units));
142 mutex_unlock(&data->lock);
145 static int amd_energy_read(struct device *dev,
146 enum hwmon_sensor_types type,
147 u32 attr, int channel, long *val)
149 struct amd_energy_data *data = dev_get_drvdata(dev);
153 if (channel >= data->nr_cpus) {
154 cpu = cpumask_first_and(cpu_online_mask,
156 (channel - data->nr_cpus));
157 reg = ENERGY_PKG_MSR;
160 if (!cpu_online(cpu))
163 reg = ENERGY_CORE_MSR;
165 amd_add_delta(data, channel, cpu, val, reg);
170 static umode_t amd_energy_is_visible(const void *_data,
171 enum hwmon_sensor_types type,
172 u32 attr, int channel)
177 static int energy_accumulator(void *p)
179 struct amd_energy_data *data = (struct amd_energy_data *)p;
180 unsigned int timeout = data->timeout_ms;
182 while (!kthread_should_stop()) {
184 * Ignoring the conditions such as
185 * cpu being offline or rdmsr failure
187 read_accumulate(data);
189 set_current_state(TASK_INTERRUPTIBLE);
190 if (kthread_should_stop())
193 schedule_timeout(msecs_to_jiffies(timeout));
198 static const struct hwmon_ops amd_energy_ops = {
199 .is_visible = amd_energy_is_visible,
200 .read = amd_energy_read,
201 .read_string = amd_energy_read_labels,
204 static int amd_create_sensor(struct device *dev,
205 struct amd_energy_data *data,
206 enum hwmon_sensor_types type, u32 config)
208 struct hwmon_channel_info *info = &data->energy_info;
209 struct sensor_accumulator *accums;
210 int i, num_siblings, cpus, sockets;
214 /* Identify the number of siblings per core */
215 num_siblings = ((cpuid_ebx(0x8000001e) >> 8) & 0xff) + 1;
217 sockets = num_possible_nodes();
220 * Energy counter register is accessed at core level.
221 * Hence, filterout the siblings.
223 cpus = num_present_cpus() / num_siblings;
225 s_config = devm_kcalloc(dev, cpus + sockets + 1,
226 sizeof(u32), GFP_KERNEL);
230 accums = devm_kcalloc(dev, cpus + sockets,
231 sizeof(struct sensor_accumulator),
236 label_l = devm_kcalloc(dev, cpus + sockets,
237 sizeof(*label_l), GFP_KERNEL);
242 info->config = s_config;
244 data->nr_cpus = cpus;
245 data->nr_socks = sockets;
246 data->accums = accums;
247 data->label = label_l;
249 for (i = 0; i < cpus + sockets; i++) {
250 s_config[i] = config;
252 scnprintf(label_l[i], 10, "Ecore%03u", i);
254 scnprintf(label_l[i], 10, "Esocket%u", (i - cpus));
261 static int amd_energy_probe(struct platform_device *pdev)
263 struct device *hwmon_dev;
264 struct amd_energy_data *data;
265 struct device *dev = &pdev->dev;
268 data = devm_kzalloc(dev,
269 sizeof(struct amd_energy_data), GFP_KERNEL);
273 data->chip.ops = &amd_energy_ops;
274 data->chip.info = data->info;
276 dev_set_drvdata(dev, data);
277 /* Populate per-core energy reporting */
278 data->info[0] = &data->energy_info;
279 ret = amd_create_sensor(dev, data, hwmon_energy,
280 HWMON_E_INPUT | HWMON_E_LABEL);
284 mutex_init(&data->lock);
285 get_energy_units(data);
287 hwmon_dev = devm_hwmon_device_register_with_info(dev, DRVNAME,
291 if (IS_ERR(hwmon_dev))
292 return PTR_ERR(hwmon_dev);
295 * On a system with peak wattage of 250W
296 * timeout = 2 ^ 32 / 2 ^ energy_units / 250 secs
298 data->timeout_ms = 1000 *
299 BIT(min(28, 31 - data->energy_units)) / 250;
301 data->wrap_accumulate = kthread_run(energy_accumulator, data,
302 "%s", dev_name(hwmon_dev));
303 return PTR_ERR_OR_ZERO(data->wrap_accumulate);
306 static int amd_energy_remove(struct platform_device *pdev)
308 struct amd_energy_data *data = dev_get_drvdata(&pdev->dev);
310 if (data && data->wrap_accumulate)
311 kthread_stop(data->wrap_accumulate);
316 static const struct platform_device_id amd_energy_ids[] = {
317 { .name = DRVNAME, },
320 MODULE_DEVICE_TABLE(platform, amd_energy_ids);
322 static struct platform_driver amd_energy_driver = {
323 .probe = amd_energy_probe,
324 .remove = amd_energy_remove,
325 .id_table = amd_energy_ids,
331 static struct platform_device *amd_energy_platdev;
333 static const struct x86_cpu_id cpu_ids[] __initconst = {
334 X86_MATCH_VENDOR_FAM_MODEL(AMD, 0x17, 0x31, NULL),
337 MODULE_DEVICE_TABLE(x86cpu, cpu_ids);
339 static int __init amd_energy_init(void)
343 if (!x86_match_cpu(cpu_ids))
346 ret = platform_driver_register(&amd_energy_driver);
350 amd_energy_platdev = platform_device_alloc(DRVNAME, 0);
351 if (!amd_energy_platdev) {
352 platform_driver_unregister(&amd_energy_driver);
356 ret = platform_device_add(amd_energy_platdev);
358 platform_device_put(amd_energy_platdev);
359 platform_driver_unregister(&amd_energy_driver);
366 static void __exit amd_energy_exit(void)
368 platform_device_unregister(amd_energy_platdev);
369 platform_driver_unregister(&amd_energy_driver);
372 module_init(amd_energy_init);
373 module_exit(amd_energy_exit);
375 MODULE_DESCRIPTION("Driver for AMD Energy reporting from RAPL MSR via HWMON interface");
376 MODULE_AUTHOR("Naveen Krishna Chatradhi <nchatrad@amd.com>");
377 MODULE_LICENSE("GPL");