1 files changed, 207 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c
new file mode 100644
index 000000000000..d32bf3593cd3
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_userspace.c
@@ -0,0 +1,207 @@
+/*
+ *  linux/drivers/cpufreq/cpufreq_userspace.c
+ *
+ *  Copyright (C)  2001 Russell King
+ *            (C)  2002 - 2004 Dominik Brodowski <linux@brodo.de>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/cpufreq.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/sysfs.h>
+
+#include <asm/uaccess.h>
+
+
+/**
+ * A few values needed by the userspace governor
+ */
+static unsigned int     cpu_max_freq[NR_CPUS];
+static unsigned int     cpu_min_freq[NR_CPUS];
+static unsigned int     cpu_cur_freq[NR_CPUS]; /* current CPU freq */
+static unsigned int     cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
+static unsigned int     cpu_is_managed[NR_CPUS];
+static struct cpufreq_policy current_policy[NR_CPUS];
+
+static DECLARE_MUTEX    (userspace_sem); 
+
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
+
+/* keep track of frequency transitions */
+static int 
+userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
+                       void *data)
+{
+        struct cpufreq_freqs *freq = data;
+
+        dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);
+        cpu_cur_freq[freq->cpu] = freq->new;
+
+        return 0;
+}
+
+static struct notifier_block userspace_cpufreq_notifier_block = {
+        .notifier_call  = userspace_cpufreq_notifier
+};
+
+
+/** 
+ * cpufreq_set - set the CPU frequency
+ * @freq: target frequency in kHz
+ * @cpu: CPU for which the frequency is to be set
+ *
+ * Sets the CPU frequency to freq.
+ */
+static int cpufreq_set(unsigned int freq, unsigned int cpu)
+{
+        int ret = -EINVAL;
+
+        dprintk("cpufreq_set for cpu %u, freq %u kHz\n", cpu, freq);
+
+        down(&userspace_sem);
+        if (!cpu_is_managed[cpu])
+                goto err;
+
+        cpu_set_freq[cpu] = freq;
+
+        if (freq < cpu_min_freq[cpu])
+                freq = cpu_min_freq[cpu];
+        if (freq > cpu_max_freq[cpu])
+                freq = cpu_max_freq[cpu];
+
+        /*
+         * We're safe from concurrent calls to ->target() here
+         * as we hold the userspace_sem lock. If we were calling
+         * cpufreq_driver_target, a deadlock situation might occur:
+         * A: cpufreq_set (lock userspace_sem) -> cpufreq_driver_target(lock policy->lock)
+         * B: cpufreq_set_policy(lock policy->lock) -> __cpufreq_governor -> cpufreq_governor_userspace (lock userspace_sem)
+         */
+        ret = __cpufreq_driver_target(&current_policy[cpu], freq, 
+              CPUFREQ_RELATION_L);
+
+ err:
+        up(&userspace_sem);
+        return ret;
+}
+
+
+/************************** sysfs interface ************************/
+static ssize_t show_speed (struct cpufreq_policy *policy, char *buf)
+{
+        return sprintf (buf, "%u\n", cpu_cur_freq[policy->cpu]);
+}
+
+static ssize_t 
+store_speed (struct cpufreq_policy *policy, const char *buf, size_t count) 
+{
+        unsigned int freq = 0;
+        unsigned int ret;
+
+        ret = sscanf (buf, "%u", &freq);
+        if (ret != 1)
+                return -EINVAL;
+
+        cpufreq_set(freq, policy->cpu);
+
+        return count;
+}
+
+static struct freq_attr freq_attr_scaling_setspeed = 
+{
+        .attr = { .name = "scaling_setspeed", .mode = 0644, .owner = THIS_MODULE },
+        .show = show_speed,
+        .store = store_speed,
+};
+
+static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
+                                   unsigned int event)
+{
+        unsigned int cpu = policy->cpu;
+        switch (event) {
+        case CPUFREQ_GOV_START:
+                if (!cpu_online(cpu))
+                        return -EINVAL;
+                BUG_ON(!policy->cur);
+                down(&userspace_sem);
+                cpu_is_managed[cpu] = 1;                
+                cpu_min_freq[cpu] = policy->min;
+                cpu_max_freq[cpu] = policy->max;
+                cpu_cur_freq[cpu] = policy->cur;
+                cpu_set_freq[cpu] = policy->cur;
+                sysfs_create_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
+                memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
+                dprintk("managing cpu %u started (%u - %u kHz, currently %u kHz)\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu]);
+                up(&userspace_sem);
+                break;
+        case CPUFREQ_GOV_STOP:
+                down(&userspace_sem);
+                cpu_is_managed[cpu] = 0;
+                cpu_min_freq[cpu] = 0;
+                cpu_max_freq[cpu] = 0;
+                cpu_set_freq[cpu] = 0;
+                sysfs_remove_file (&policy->kobj, &freq_attr_scaling_setspeed.attr);
+                dprintk("managing cpu %u stopped\n", cpu);
+                up(&userspace_sem);
+                break;
+        case CPUFREQ_GOV_LIMITS:
+                down(&userspace_sem);
+                cpu_min_freq[cpu] = policy->min;
+                cpu_max_freq[cpu] = policy->max;
+                dprintk("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n", cpu, cpu_min_freq[cpu], cpu_max_freq[cpu], cpu_cur_freq[cpu], cpu_set_freq[cpu]);
+                if (policy->max < cpu_set_freq[cpu]) {
+                        __cpufreq_driver_target(&current_policy[cpu], policy->max, 
+                              CPUFREQ_RELATION_H);
+                } else if (policy->min > cpu_set_freq[cpu]) {
+                        __cpufreq_driver_target(&current_policy[cpu], policy->min, 
+                              CPUFREQ_RELATION_L);
+                } else {
+                        __cpufreq_driver_target(&current_policy[cpu], cpu_set_freq[cpu],
+                              CPUFREQ_RELATION_L);
+                }
+                memcpy (&current_policy[cpu], policy, sizeof(struct cpufreq_policy));
+                up(&userspace_sem);
+                break;
+        }
+        return 0;
+}
+
+
+struct cpufreq_governor cpufreq_gov_userspace = {
+        .name           = "userspace",
+        .governor       = cpufreq_governor_userspace,
+        .owner          = THIS_MODULE,
+};
+EXPORT_SYMBOL(cpufreq_gov_userspace);
+
+static int __init cpufreq_gov_userspace_init(void)
+{
+        cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
+        return cpufreq_register_governor(&cpufreq_gov_userspace);
+}
+
+
+static void __exit cpufreq_gov_userspace_exit(void)
+{
+        cpufreq_unregister_governor(&cpufreq_gov_userspace);
+        cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+
+MODULE_AUTHOR ("Dominik Brodowski <linux@brodo.de>, Russell King <rmk@arm.linux.org.uk>");
+MODULE_DESCRIPTION ("CPUfreq policy governor 'userspace'");
+MODULE_LICENSE ("GPL");
+
+fs_initcall(cpufreq_gov_userspace_init);
+module_exit(cpufreq_gov_userspace_exit);