1 files changed, 106 insertions, 0 deletions
diff --git a/kernel/drivers/macintosh/windfarm_cpufreq_clamp.c b/kernel/drivers/macintosh/windfarm_cpufreq_clamp.c
new file mode 100644
index 000000000..72d1fdfe0
--- /dev/null
+++ b/kernel/drivers/macintosh/windfarm_cpufreq_clamp.c
@@ -0,0 +1,106 @@
+#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 <asm/prom.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");
+