1 files changed, 105 insertions, 0 deletions

diff --git a/drivers/macintosh/windfarm_cpufreq_clamp.c b/drivers/macintosh/windfarm_cpufreq_clamp.c
new file mode 100644
index 000000000000..607dbaca69c9
--- /dev/null
+++ b/drivers/macintosh/windfarm_cpufreq_clamp.c
@@ -0,0 +1,105 @@
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/cpufreq.h>
+
+#include "windfarm.h"
+
+#define VERSION "0.3"
+
+static int clamped;
+static struct wf_control *clamp_control;
+
+static int clamp_notifier_call(struct notifier_block *self,
+                               unsigned long event, void *data)
+{
+        struct cpufreq_policy *p = data;
+        unsigned long max_freq;
+
+        if (event != CPUFREQ_ADJUST)
+                return 0;
+
+        max_freq = clamped ? (p->cpuinfo.min_freq) : (p->cpuinfo.max_freq);
+        cpufreq_verify_within_limits(p, 0, max_freq);
+
+        return 0;
+}
+
+static struct notifier_block clamp_notifier = {
+        .notifier_call = clamp_notifier_call,
+};
+
+static int clamp_set(struct wf_control *ct, s32 value)
+{
+        if (value)
+                printk(KERN_INFO "windfarm: Clamping CPU frequency to "
+                       "minimum !\n");
+        else
+                printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
+        clamped = value;
+        cpufreq_update_policy(0);
+        return 0;
+}
+
+static int clamp_get(struct wf_control *ct, s32 *value)
+{
+        *value = clamped;
+        return 0;
+}
+
+static s32 clamp_min(struct wf_control *ct)
+{
+        return 0;
+}
+
+static s32 clamp_max(struct wf_control *ct)
+{
+        return 1;
+}
+
+static struct wf_control_ops clamp_ops = {
+        .set_value      = clamp_set,
+        .get_value      = clamp_get,
+        .get_min        = clamp_min,
+        .get_max        = clamp_max,
+        .owner          = THIS_MODULE,
+};
+
+static int __init wf_cpufreq_clamp_init(void)
+{
+        struct wf_control *clamp;
+
+        clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL);
+        if (clamp == NULL)
+                return -ENOMEM;
+        cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER);
+        clamp->ops = &clamp_ops;
+        clamp->name = "cpufreq-clamp";
+        if (wf_register_control(clamp))
+                goto fail;
+        clamp_control = clamp;
+        return 0;
+ fail:
+        kfree(clamp);
+        return -ENODEV;
+}
+
+static void __exit wf_cpufreq_clamp_exit(void)
+{
+        if (clamp_control)
+                wf_unregister_control(clamp_control);
+}
+
+
+module_init(wf_cpufreq_clamp_init);
+module_exit(wf_cpufreq_clamp_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
+MODULE_LICENSE("GPL");
+