4 files changed, 339 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index de03ca58db5d..bf86b03d5af2 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -232,7 +232,8 @@
 #define H_GET_EM_PARMS          0x2B8
 #define H_SET_MPP               0x2D0
 #define H_GET_MPP               0x2D4
-#define MAX_HCALL_OPCODE        H_GET_MPP
+#define H_BEST_ENERGY           0x2F4
+#define MAX_HCALL_OPCODE        H_BEST_ENERGY
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index 3139814f6439..5d1b743dbe7e 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -33,6 +33,16 @@ config PSERIES_MSI
        depends on PCI_MSI && EEH
        default y
 
+config PSERIES_ENERGY
+        tristate "pSeries energy management capabilities driver"
+        depends on PPC_PSERIES
+        default y
+        help
+          Provides interface to platform energy management capabilities
+          on supported PSERIES platforms.
+          Provides: /sys/devices/system/cpu/pseries_(de)activation_hint_list
+          and /sys/devices/system/cpu/cpuN/pseries_(de)activation_hint
+
 config SCANLOG
         tristate "Scanlog dump interface"
         depends on RTAS_PROC && PPC_PSERIES
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 59eb8bdaa79d..fc5237810ece 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_EEH)	+= eeh.o eeh_cache.o eeh_driver.o eeh_event.o eeh_sysfs.o
 obj-$(CONFIG_KEXEC)     += kexec.o
 obj-$(CONFIG_PCI)       += pci.o pci_dlpar.o
 obj-$(CONFIG_PSERIES_MSI)       += msi.o
+obj-$(CONFIG_PSERIES_ENERGY)    += pseries_energy.o
 
 obj-$(CONFIG_HOTPLUG_CPU)       += hotplug-cpu.o
 obj-$(CONFIG_MEMORY_HOTPLUG)    += hotplug-memory.o
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");