/arch/powerpc/platforms/pseries/pseries_energy.c

  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
 30static int sysfs_entries;
 31
 32/* Helper routines */
 33
 34/* Helper Routines to convert between drc_index to cpu numbers */
 35
 36static 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
101err_of_node_put:
102	of_node_put(dn);
103err:
104	if (rc)
105		printk(KERN_WARNING "cpu_to_drc_index(%d) failed", cpu);
106	return ret;
107}
108
109static 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
170err_of_node_put:
171	of_node_put(dn);
172err:
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
188static 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
227static 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
250static 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
256static 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
262static 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
268static 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
284static struct device_attribute attr_cpu_activate_hint_list =
285		__ATTR(pseries_activate_hint_list, 0444,
286		cpu_activate_hint_list_show, NULL);
287
288static struct device_attribute attr_cpu_deactivate_hint_list =
289		__ATTR(pseries_deactivate_hint_list, 0444,
290		cpu_deactivate_hint_list_show, NULL);
291
292static struct device_attribute attr_percpu_activate_hint =
293		__ATTR(pseries_activate_hint, 0444,
294		percpu_activate_hint_show, NULL);
295
296static struct device_attribute attr_percpu_deactivate_hint =
297		__ATTR(pseries_deactivate_hint, 0444,
298		percpu_deactivate_hint_show, NULL);
299
300static int __init pseries_energy_init(void)
301{
302	int cpu, err;
303	struct device *cpu_dev;
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	err = device_create_file(cpu_subsys.dev_root,
310				&attr_cpu_activate_hint_list);
311	if (!err)
312		err = device_create_file(cpu_subsys.dev_root,
313				&attr_cpu_deactivate_hint_list);
314
315	if (err)
316		return err;
317	for_each_possible_cpu(cpu) {
318		cpu_dev = get_cpu_device(cpu);
319		err = device_create_file(cpu_dev,
320				&attr_percpu_activate_hint);
321		if (err)
322			break;
323		err = device_create_file(cpu_dev,
324				&attr_percpu_deactivate_hint);
325		if (err)
326			break;
327	}
328
329	if (err)
330		return err;
331
332	sysfs_entries = 1; /* Removed entries on cleanup */
333	return 0;
334
335}
336
337static void __exit pseries_energy_cleanup(void)
338{
339	int cpu;
340	struct device *cpu_dev;
341
342	if (!sysfs_entries)
343		return;
344
345	/* Remove the sysfs files */
346	device_remove_file(cpu_subsys.dev_root, &attr_cpu_activate_hint_list);
347	device_remove_file(cpu_subsys.dev_root, &attr_cpu_deactivate_hint_list);
348
349	for_each_possible_cpu(cpu) {
350		cpu_dev = get_cpu_device(cpu);
351		sysfs_remove_file(&cpu_dev->kobj,
352				&attr_percpu_activate_hint.attr);
353		sysfs_remove_file(&cpu_dev->kobj,
354				&attr_percpu_deactivate_hint.attr);
355	}
356}
357
358module_init(pseries_energy_init);
359module_exit(pseries_energy_cleanup);
360MODULE_DESCRIPTION("Driver for pSeries platform energy management");
361MODULE_AUTHOR("Vaidyanathan Srinivasan");
362MODULE_LICENSE("GPL");