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Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/platforms/pseries/pseries_energy.c | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c new file mode 100644 index 000000000000..c8b3c69fe891 --- /dev/null +++ b/arch/powerpc/platforms/pseries/pseries_energy.c @@ -0,0 +1,326 @@ +/* + * 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"); 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