1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * POWER platform energy management driver
4 * Copyright (C) 2010 IBM Corporation
5 *
6 * This pseries platform device driver provides access to
7 * platform energy management capabilities.
8 */
9
10 #include <linux/module.h>
11 #include <linux/types.h>
12 #include <linux/errno.h>
13 #include <linux/init.h>
14 #include <linux/seq_file.h>
15 #include <linux/device.h>
16 #include <linux/cpu.h>
17 #include <linux/of.h>
18 #include <asm/cputhreads.h>
19 #include <asm/page.h>
20 #include <asm/hvcall.h>
21 #include <asm/firmware.h>
22 #include <asm/prom.h>
23
24
25 #define MODULE_VERS "1.0"
26 #define MODULE_NAME "pseries_energy"
27
28 /* Driver flags */
29
30 static int sysfs_entries;
31
32 /* Helper routines */
33
34 /* Helper Routines to convert between drc_index to cpu numbers */
35
cpu_to_drc_index(int cpu)36 static u32 cpu_to_drc_index(int cpu)
37 {
38 struct device_node *dn = NULL;
39 struct property *info;
40 int thread_index;
41 int rc = 1;
42 u32 ret = 0;
43
44 dn = of_find_node_by_path("/cpus");
45 if (dn == NULL)
46 goto err;
47
48 /* Convert logical cpu number to core number */
49 thread_index = cpu_core_index_of_thread(cpu);
50
51 info = of_find_property(dn, "ibm,drc-info", NULL);
52 if (info) {
53 struct of_drc_info drc;
54 int j;
55 u32 num_set_entries;
56 const __be32 *value;
57
58 value = of_prop_next_u32(info, NULL, &num_set_entries);
59 if (!value)
60 goto err_of_node_put;
61 else
62 value++;
63
64 for (j = 0; j < num_set_entries; j++) {
65
66 of_read_drc_info_cell(&info, &value, &drc);
67 if (strncmp(drc.drc_type, "CPU", 3))
68 goto err;
69
70 if (thread_index < drc.last_drc_index)
71 break;
72 }
73
74 ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
75 } else {
76 u32 nr_drc_indexes, thread_drc_index;
77
78 /*
79 * The first element of ibm,drc-indexes array is the
80 * number of drc_indexes returned in the list. Hence
81 * thread_index+1 will get the drc_index corresponding
82 * to core number thread_index.
83 */
84 rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
85 0, &nr_drc_indexes);
86 if (rc)
87 goto err_of_node_put;
88
89 WARN_ON_ONCE(thread_index > nr_drc_indexes);
90 rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
91 thread_index + 1,
92 &thread_drc_index);
93 if (rc)
94 goto err_of_node_put;
95
96 ret = thread_drc_index;
97 }
98
99 rc = 0;
100
101 err_of_node_put:
102 of_node_put(dn);
103 err:
104 if (rc)
105 printk(KERN_WARNING "cpu_to_drc_index(%d) failed", cpu);
106 return ret;
107 }
108
drc_index_to_cpu(u32 drc_index)109 static int drc_index_to_cpu(u32 drc_index)
110 {
111 struct device_node *dn = NULL;
112 struct property *info;
113 const int *indexes;
114 int thread_index = 0, cpu = 0;
115 int rc = 1;
116
117 dn = of_find_node_by_path("/cpus");
118 if (dn == NULL)
119 goto err;
120 info = of_find_property(dn, "ibm,drc-info", NULL);
121 if (info) {
122 struct of_drc_info drc;
123 int j;
124 u32 num_set_entries;
125 const __be32 *value;
126
127 value = of_prop_next_u32(info, NULL, &num_set_entries);
128 if (!value)
129 goto err_of_node_put;
130 else
131 value++;
132
133 for (j = 0; j < num_set_entries; j++) {
134
135 of_read_drc_info_cell(&info, &value, &drc);
136 if (strncmp(drc.drc_type, "CPU", 3))
137 goto err;
138
139 if (drc_index > drc.last_drc_index) {
140 cpu += drc.num_sequential_elems;
141 continue;
142 }
143 cpu += ((drc_index - drc.drc_index_start) /
144 drc.sequential_inc);
145
146 thread_index = cpu_first_thread_of_core(cpu);
147 rc = 0;
148 break;
149 }
150 } else {
151 unsigned long int i;
152
153 indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
154 if (indexes == NULL)
155 goto err_of_node_put;
156 /*
157 * First element in the array is the number of drc_indexes
158 * returned. Search through the list to find the matching
159 * drc_index and get the core number
160 */
161 for (i = 0; i < indexes[0]; i++) {
162 if (indexes[i + 1] == drc_index)
163 break;
164 }
165 /* Convert core number to logical cpu number */
166 thread_index = cpu_first_thread_of_core(i);
167 rc = 0;
168 }
169
170 err_of_node_put:
171 of_node_put(dn);
172 err:
173 if (rc)
174 printk(KERN_WARNING "drc_index_to_cpu(%d) failed", drc_index);
175 return thread_index;
176 }
177
178 /*
179 * pseries hypervisor call H_BEST_ENERGY provides hints to OS on
180 * preferred logical cpus to activate or deactivate for optimized
181 * energy consumption.
182 */
183
184 #define FLAGS_MODE1 0x004E200000080E01UL
185 #define FLAGS_MODE2 0x004E200000080401UL
186 #define FLAGS_ACTIVATE 0x100
187
get_best_energy_list(char * page,int activate)188 static ssize_t get_best_energy_list(char *page, int activate)
189 {
190 int rc, cnt, i, cpu;
191 unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
192 unsigned long flags = 0;
193 u32 *buf_page;
194 char *s = page;
195
196 buf_page = (u32 *) get_zeroed_page(GFP_KERNEL);
197 if (!buf_page)
198 return -ENOMEM;
199
200 flags = FLAGS_MODE1;
201 if (activate)
202 flags |= FLAGS_ACTIVATE;
203
204 rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags, 0, __pa(buf_page),
205 0, 0, 0, 0, 0, 0);
206 if (rc != H_SUCCESS) {
207 free_page((unsigned long) buf_page);
208 return -EINVAL;
209 }
210
211 cnt = retbuf[0];
212 for (i = 0; i < cnt; i++) {
213 cpu = drc_index_to_cpu(buf_page[2*i+1]);
214 if ((cpu_online(cpu) && !activate) ||
215 (!cpu_online(cpu) && activate))
216 s += sprintf(s, "%d,", cpu);
217 }
218 if (s > page) { /* Something to show */
219 s--; /* Suppress last comma */
220 s += sprintf(s, "\n");
221 }
222
223 free_page((unsigned long) buf_page);
224 return s-page;
225 }
226
get_best_energy_data(struct device * dev,char * page,int activate)227 static ssize_t get_best_energy_data(struct device *dev,
228 char *page, int activate)
229 {
230 int rc;
231 unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
232 unsigned long flags = 0;
233
234 flags = FLAGS_MODE2;
235 if (activate)
236 flags |= FLAGS_ACTIVATE;
237
238 rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags,
239 cpu_to_drc_index(dev->id),
240 0, 0, 0, 0, 0, 0, 0);
241
242 if (rc != H_SUCCESS)
243 return -EINVAL;
244
245 return sprintf(page, "%lu\n", retbuf[1] >> 32);
246 }
247
248 /* Wrapper functions */
249
cpu_activate_hint_list_show(struct device * dev,struct device_attribute * attr,char * page)250 static ssize_t cpu_activate_hint_list_show(struct device *dev,
251 struct device_attribute *attr, char *page)
252 {
253 return get_best_energy_list(page, 1);
254 }
255
cpu_deactivate_hint_list_show(struct device * dev,struct device_attribute * attr,char * page)256 static ssize_t cpu_deactivate_hint_list_show(struct device *dev,
257 struct device_attribute *attr, char *page)
258 {
259 return get_best_energy_list(page, 0);
260 }
261
percpu_activate_hint_show(struct device * dev,struct device_attribute * attr,char * page)262 static ssize_t percpu_activate_hint_show(struct device *dev,
263 struct device_attribute *attr, char *page)
264 {
265 return get_best_energy_data(dev, page, 1);
266 }
267
percpu_deactivate_hint_show(struct device * dev,struct device_attribute * attr,char * page)268 static ssize_t percpu_deactivate_hint_show(struct device *dev,
269 struct device_attribute *attr, char *page)
270 {
271 return get_best_energy_data(dev, page, 0);
272 }
273
274 /*
275 * Create sysfs interface:
276 * /sys/devices/system/cpu/pseries_activate_hint_list
277 * /sys/devices/system/cpu/pseries_deactivate_hint_list
278 * Comma separated list of cpus to activate or deactivate
279 * /sys/devices/system/cpu/cpuN/pseries_activate_hint
280 * /sys/devices/system/cpu/cpuN/pseries_deactivate_hint
281 * Per-cpu value of the hint
282 */
283
284 static struct device_attribute attr_cpu_activate_hint_list =
285 __ATTR(pseries_activate_hint_list, 0444,
286 cpu_activate_hint_list_show, NULL);
287
288 static struct device_attribute attr_cpu_deactivate_hint_list =
289 __ATTR(pseries_deactivate_hint_list, 0444,
290 cpu_deactivate_hint_list_show, NULL);
291
292 static struct device_attribute attr_percpu_activate_hint =
293 __ATTR(pseries_activate_hint, 0444,
294 percpu_activate_hint_show, NULL);
295
296 static struct device_attribute attr_percpu_deactivate_hint =
297 __ATTR(pseries_deactivate_hint, 0444,
298 percpu_deactivate_hint_show, NULL);
299
pseries_energy_init(void)300 static int __init pseries_energy_init(void)
301 {
302 int cpu, err;
303 struct device *cpu_dev, *dev_root;
304
305 if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY))
306 return 0; /* H_BEST_ENERGY hcall not supported */
307
308 /* Create the sysfs files */
309 dev_root = bus_get_dev_root(&cpu_subsys);
310 if (dev_root) {
311 err = device_create_file(dev_root, &attr_cpu_activate_hint_list);
312 if (!err)
313 err = device_create_file(dev_root, &attr_cpu_deactivate_hint_list);
314 put_device(dev_root);
315 if (err)
316 return err;
317 }
318
319 for_each_possible_cpu(cpu) {
320 cpu_dev = get_cpu_device(cpu);
321 err = device_create_file(cpu_dev,
322 &attr_percpu_activate_hint);
323 if (err)
324 break;
325 err = device_create_file(cpu_dev,
326 &attr_percpu_deactivate_hint);
327 if (err)
328 break;
329 }
330
331 if (err)
332 return err;
333
334 sysfs_entries = 1; /* Removed entries on cleanup */
335 return 0;
336
337 }
338
pseries_energy_cleanup(void)339 static void __exit pseries_energy_cleanup(void)
340 {
341 int cpu;
342 struct device *cpu_dev, *dev_root;
343
344 if (!sysfs_entries)
345 return;
346
347 /* Remove the sysfs files */
348 dev_root = bus_get_dev_root(&cpu_subsys);
349 if (dev_root) {
350 device_remove_file(dev_root, &attr_cpu_activate_hint_list);
351 device_remove_file(dev_root, &attr_cpu_deactivate_hint_list);
352 put_device(dev_root);
353 }
354
355 for_each_possible_cpu(cpu) {
356 cpu_dev = get_cpu_device(cpu);
357 sysfs_remove_file(&cpu_dev->kobj,
358 &attr_percpu_activate_hint.attr);
359 sysfs_remove_file(&cpu_dev->kobj,
360 &attr_percpu_deactivate_hint.attr);
361 }
362 }
363
364 module_init(pseries_energy_init);
365 module_exit(pseries_energy_cleanup);
366 MODULE_DESCRIPTION("Driver for pSeries platform energy management");
367 MODULE_AUTHOR("Vaidyanathan Srinivasan");
368 MODULE_LICENSE("GPL");
369