// SPDX-License-Identifier: GPL-2.0-only
/*
* POWER platform energy management driver
* Copyright (C) 2010 IBM Corporation
*
* This pseries platform device driver provides access to
* platform energy management capabilities.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <asm/cputhreads.h>
#include <asm/page.h>
#include <asm/hvcall.h>
#include <asm/firmware.h>
#include <asm/prom.h>
#define MODULE_VERS "1.0"
#define MODULE_NAME "pseries_energy"
/* Driver flags */
static int sysfs_entries;
/* Helper routines */
/* Helper Routines to convert between drc_index to cpu numbers */
static u32 cpu_to_drc_index(int cpu)
{
struct device_node *dn = NULL;
struct property *info;
int thread_index;
int rc = 1;
u32 ret = 0;
dn = of_find_node_by_path("/cpus");
if (dn == NULL)
goto err;
/* Convert logical cpu number to core number */
thread_index = cpu_core_index_of_thread(cpu);
info = of_find_property(dn, "ibm,drc-info", NULL);
if (info) {
struct of_drc_info drc;
int j;
u32 num_set_entries;
const __be32 *value;
value = of_prop_next_u32(info, NULL, &num_set_entries);
if (!value)
goto err_of_node_put;
else
value++;
for (j = 0; j < num_set_entries; j++) {
of_read_drc_info_cell(&info, &value, &drc);
if (strncmp(drc.drc_type, "CPU", 3))
goto err;
if (thread_index < drc.last_drc_index)
break;
}
ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
} else {
u32 nr_drc_indexes, thread_drc_index;
/*
* The first element of ibm,drc-indexes array is the
* number of drc_indexes returned in the list. Hence
* thread_index+1 will get the drc_index corresponding
* to core number thread_index.
*/
rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
0, &nr_drc_indexes);
if (rc)
goto err_of_node_put;
WARN_ON_ONCE(thread_index > nr_drc_indexes);
rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
thread_index + 1,
&thread_drc_index);
if (rc)
goto err_of_node_put;
ret = thread_drc_index;
}
rc = 0;
err_of_node_put:
of_node_put(dn);
err:
if (rc)
printk(KERN_WARNING "cpu_to_drc_index(%d) failed", cpu);
return ret;
}
static int drc_index_to_cpu(u32 drc_index)
{
struct device_node *dn = NULL;
struct property *info;
const int *indexes;
int thread_index = 0, cpu = 0;
int rc = 1;
dn = of_find_node_by_path("/cpus");
if (dn == NULL)
goto err;
info = of_find_property(dn, "ibm,drc-info", NULL);
if (info) {
struct of_drc_info drc;
int j;
u32 num_set_entries;
const __be32 *value;
value = of_prop_next_u32(info, NULL, &num_set_entries);
if (!value)
goto err_of_node_put;
else
value++;
for (j = 0; j < num_set_entries; j++) {
of_read_drc_info_cell(&info, &value, &drc);
if (strncmp(drc.drc_type, "CPU", 3))
goto err;
if (drc_index > drc.last_drc_index) {
cpu += drc.num_sequential_elems;
continue;
}
cpu += ((drc_index - drc.drc_index_start) /
drc.sequential_inc);
thread_index = cpu_first_thread_of_core(cpu);
rc = 0;
break;
}
} else {
unsigned long int i;
indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
if (indexes == NULL)
goto err_of_node_put;
/*
* First element in the array is the number of drc_indexes
* returned. Search through the list to find the matching
* drc_index and get the core number
*/
for (i = 0; i < indexes[0]; i++) {
if (indexes[i + 1] == drc_index)
break;
}
/* Convert core number to logical cpu number */
thread_index = cpu_first_thread_of_core(i);
rc = 0;
}
err_of_node_put:
of_node_put(dn);
err:
if (rc)
printk(KERN_WARNING "drc_index_to_cpu(%d) failed", drc_index);
return thread_index;
}
/*
* pseries hypervisor call H_BEST_ENERGY provides hints to OS on
* preferred logical cpus to activate or deactivate for optimized
* energy consumption.
*/
#define FLAGS_MODE1 0x004E200000080E01UL
#define FLAGS_MODE2 0x004E200000080401UL
#define FLAGS_ACTIVATE 0x100
static ssize_t get_best_energy_list(char *page, int activate)
{
int rc, cnt, i, cpu;
unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
unsigned long flags = 0;
u32 *buf_page;
char *s = page;
buf_page = (u32 *) get_zeroed_page(GFP_KERNEL);
if (!buf_page)
return -ENOMEM;
flags = FLAGS_MODE1;
if (activate)
flags |= FLAGS_ACTIVATE;
rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags, 0, __pa(buf_page),
0, 0, 0, 0, 0, 0);
if (rc != H_SUCCESS) {
free_page((unsigned long) buf_page);
return -EINVAL;
}
cnt = retbuf[0];
for (i = 0; i < cnt; i++) {
cpu = drc_index_to_cpu(buf_page[2*i+1]);
if ((cpu_online(cpu) && !activate) ||
(!cpu_online(cpu) && activate))
s += sprintf(s, "%d,", cpu);
}
if (s > page) { /* Something to show */
s--; /* Suppress last comma */
s += sprintf(s, "\n");
}
free_page((unsigned long) buf_page);
return s-page;
}
static ssize_t get_best_energy_data(struct device *dev,
char *page, int activate)
{
int rc;
unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
unsigned long flags = 0;
flags = FLAGS_MODE2;
if (activate)
flags |= FLAGS_ACTIVATE;
rc = plpar_hcall9(H_BEST_ENERGY, retbuf, flags,
cpu_to_drc_index(dev->id),
0, 0, 0, 0, 0, 0, 0);
if (rc != H_SUCCESS)
return -EINVAL;
return sprintf(page, "%lu\n", retbuf[1] >> 32);
}
/* Wrapper functions */
static ssize_t cpu_activate_hint_list_show(struct device *dev,
struct device_attribute *attr, char *page)
{
return get_best_energy_list(page, 1);
}
static ssize_t cpu_deactivate_hint_list_show(struct device *dev,
struct device_attribute *attr, char *page)
{
return get_best_energy_list(page, 0);
}
static ssize_t percpu_activate_hint_show(struct device *dev,
struct device_attribute *attr, char *page)
{
return get_best_energy_data(dev, page, 1);
}
static ssize_t percpu_deactivate_hint_show(struct device *dev,
struct device_attribute *attr, char *page)
{
return get_best_energy_data(dev, page, 0);
}
/*
* Create sysfs interface:
* /sys/devices/system/cpu/pseries_activate_hint_list
* /sys/devices/system/cpu/pseries_deactivate_hint_list
* Comma separated list of cpus to activate or deactivate
* /sys/devices/system/cpu/cpuN/pseries_activate_hint
* /sys/devices/system/cpu/cpuN/pseries_deactivate_hint
* Per-cpu value of the hint
*/
static struct device_attribute attr_cpu_activate_hint_list =
__ATTR(pseries_activate_hint_list, 0444,
cpu_activate_hint_list_show, NULL);
static struct device_attribute attr_cpu_deactivate_hint_list =
__ATTR(pseries_deactivate_hint_list, 0444,
cpu_deactivate_hint_list_show, NULL);
static struct device_attribute attr_percpu_activate_hint =
__ATTR(pseries_activate_hint, 0444,
percpu_activate_hint_show, NULL);
static struct device_attribute attr_percpu_deactivate_hint =
__ATTR(pseries_deactivate_hint, 0444,
percpu_deactivate_hint_show, NULL);
static int __init pseries_energy_init(void)
{
int cpu, err;
struct device *cpu_dev, *dev_root;
if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY))
return 0; /* H_BEST_ENERGY hcall not supported */
/* Create the sysfs files */
dev_root = bus_get_dev_root(&cpu_subsys);
if (dev_root) {
err = device_create_file(dev_root, &attr_cpu_activate_hint_list);
if (!err)
err = device_create_file(dev_root, &attr_cpu_deactivate_hint_list);
put_device(dev_root);
if (err)
return err;
}
for_each_possible_cpu(cpu) {
cpu_dev = get_cpu_device(cpu);
err = device_create_file(cpu_dev,
&attr_percpu_activate_hint);
if (err)
break;
err = device_create_file(cpu_dev,
&attr_percpu_deactivate_hint);
if (err)
break;
}
if (err)
return err;
sysfs_entries = 1; /* Removed entries on cleanup */
return 0;
}
static void __exit pseries_energy_cleanup(void)
{
int cpu;
struct device *cpu_dev, *dev_root;
if (!sysfs_entries)
return;
/* Remove the sysfs files */
dev_root = bus_get_dev_root(&cpu_subsys);
if (dev_root) {
device_remove_file(dev_root, &attr_cpu_activate_hint_list);
device_remove_file(dev_root, &attr_cpu_deactivate_hint_list);
put_device(dev_root);
}
for_each_possible_cpu(cpu) {
cpu_dev = get_cpu_device(cpu);
sysfs_remove_file(&cpu_dev->kobj,
&attr_percpu_activate_hint.attr);
sysfs_remove_file(&cpu_dev->kobj,
&attr_percpu_deactivate_hint.attr);
}
}
module_init(pseries_energy_init);
module_exit(pseries_energy_cleanup);
MODULE_DESCRIPTION("Driver for pSeries platform energy management");
MODULE_AUTHOR("Vaidyanathan Srinivasan");
MODULE_LICENSE("GPL");
Codebase Browser
linux