--- /dev/null
+/*
+ * POWER platform energy management driver
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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/sysdev.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <asm/cputhreads.h>
+#include <asm/page.h>
+#include <asm/hvcall.h>
+
+
+#define MODULE_VERS "1.0"
+#define MODULE_NAME "pseries_energy"
+
+/* Driver flags */
+
+static int sysfs_entries;
+
+/* Helper routines */
+
+/*
+ * Routine to detect firmware support for hcall
+ * return 1 if H_BEST_ENERGY is supported
+ * else return 0
+ */
+
+static int check_for_h_best_energy(void)
+{
+ struct device_node *rtas = NULL;
+ const char *hypertas, *s;
+ int length;
+ int rc = 0;
+
+ rtas = of_find_node_by_path("/rtas");
+ if (!rtas)
+ return 0;
+
+ hypertas = of_get_property(rtas, "ibm,hypertas-functions", &length);
+ if (!hypertas) {
+ of_node_put(rtas);
+ return 0;
+ }
+
+ /* hypertas will have list of strings with hcall names */
+ for (s = hypertas; s < hypertas + length; s += strlen(s) + 1) {
+ if (!strncmp("hcall-best-energy-1", s, 19)) {
+ rc = 1; /* Found the string */
+ break;
+ }
+ }
+ of_node_put(rtas);
+ return rc;
+}
+
+/* Helper Routines to convert between drc_index to cpu numbers */
+
+static u32 cpu_to_drc_index(int cpu)
+{
+ struct device_node *dn = NULL;
+ const int *indexes;
+ int i;
+ int rc = 1;
+ u32 ret = 0;
+
+ dn = of_find_node_by_path("/cpus");
+ if (dn == NULL)
+ goto err;
+ indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
+ if (indexes == NULL)
+ goto err_of_node_put;
+ /* Convert logical cpu number to core number */
+ i = cpu_core_index_of_thread(cpu);
+ /*
+ * The first element indexes[0] is the number of drc_indexes
+ * returned in the list. Hence i+1 will get the drc_index
+ * corresponding to core number i.
+ */
+ WARN_ON(i > indexes[0]);
+ ret = indexes[i + 1];
+ 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;
+ const int *indexes;
+ int i, cpu = 0;
+ int rc = 1;
+
+ dn = of_find_node_by_path("/cpus");
+ if (dn == NULL)
+ goto err;
+ 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 */
+ cpu = 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 cpu;
+}
+
+/*
+ * 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 0x004E200000080E01
+#define FLAGS_MODE2 0x004E200000080401
+#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 sys_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 sysdev_class *class,
+ struct sysdev_class_attribute *attr, char *page)
+{
+ return get_best_energy_list(page, 1);
+}
+
+static ssize_t cpu_deactivate_hint_list_show(struct sysdev_class *class,
+ struct sysdev_class_attribute *attr, char *page)
+{
+ return get_best_energy_list(page, 0);
+}
+
+static ssize_t percpu_activate_hint_show(struct sys_device *dev,
+ struct sysdev_attribute *attr, char *page)
+{
+ return get_best_energy_data(dev, page, 1);
+}
+
+static ssize_t percpu_deactivate_hint_show(struct sys_device *dev,
+ struct sysdev_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
+ */
+
+struct sysdev_class_attribute attr_cpu_activate_hint_list =
+ _SYSDEV_CLASS_ATTR(pseries_activate_hint_list, 0444,
+ cpu_activate_hint_list_show, NULL);
+
+struct sysdev_class_attribute attr_cpu_deactivate_hint_list =
+ _SYSDEV_CLASS_ATTR(pseries_deactivate_hint_list, 0444,
+ cpu_deactivate_hint_list_show, NULL);
+
+struct sysdev_attribute attr_percpu_activate_hint =
+ _SYSDEV_ATTR(pseries_activate_hint, 0444,
+ percpu_activate_hint_show, NULL);
+
+struct sysdev_attribute attr_percpu_deactivate_hint =
+ _SYSDEV_ATTR(pseries_deactivate_hint, 0444,
+ percpu_deactivate_hint_show, NULL);
+
+static int __init pseries_energy_init(void)
+{
+ int cpu, err;
+ struct sys_device *cpu_sys_dev;
+
+ if (!check_for_h_best_energy()) {
+ printk(KERN_INFO "Hypercall H_BEST_ENERGY not supported\n");
+ return 0;
+ }
+ /* Create the sysfs files */
+ err = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
+ &attr_cpu_activate_hint_list.attr);
+ if (!err)
+ err = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
+ &attr_cpu_deactivate_hint_list.attr);
+
+ if (err)
+ return err;
+ for_each_possible_cpu(cpu) {
+ cpu_sys_dev = get_cpu_sysdev(cpu);
+ err = sysfs_create_file(&cpu_sys_dev->kobj,
+ &attr_percpu_activate_hint.attr);
+ if (err)
+ break;
+ err = sysfs_create_file(&cpu_sys_dev->kobj,
+ &attr_percpu_deactivate_hint.attr);
+ 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 sys_device *cpu_sys_dev;
+
+ if (!sysfs_entries)
+ return;
+
+ /* Remove the sysfs files */
+ sysfs_remove_file(&cpu_sysdev_class.kset.kobj,
+ &attr_cpu_activate_hint_list.attr);
+
+ sysfs_remove_file(&cpu_sysdev_class.kset.kobj,
+ &attr_cpu_deactivate_hint_list.attr);
+
+ for_each_possible_cpu(cpu) {
+ cpu_sys_dev = get_cpu_sysdev(cpu);
+ sysfs_remove_file(&cpu_sys_dev->kobj,
+ &attr_percpu_activate_hint.attr);
+ sysfs_remove_file(&cpu_sys_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");
projects / platform / kernel / linux-rpi.git / commitdiff