/arch/powerpc/platforms/pseries/pseries_energy.c
http://github.com/mirrors/linux · C · 362 lines · 256 code · 65 blank · 41 comment · 44 complexity · a029574f17e1d586a72fcc8c28062abb MD5 · raw file
- // 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;
- if (!firmware_has_feature(FW_FEATURE_BEST_ENERGY))
- return 0; /* H_BEST_ENERGY hcall not supported */
- /* Create the sysfs files */
- err = device_create_file(cpu_subsys.dev_root,
- &attr_cpu_activate_hint_list);
- if (!err)
- err = device_create_file(cpu_subsys.dev_root,
- &attr_cpu_deactivate_hint_list);
- 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;
- if (!sysfs_entries)
- return;
- /* Remove the sysfs files */
- device_remove_file(cpu_subsys.dev_root, &attr_cpu_activate_hint_list);
- device_remove_file(cpu_subsys.dev_root, &attr_cpu_deactivate_hint_list);
- 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");