Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 197 insertions, 0 deletions

diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
new file mode 100644
index 0000000000..8e9058c4ea
--- /dev/null
+++ b/drivers/cpuidle/governors/ladder.c
@@ -0,0 +1,197 @@
+/*
+ * ladder.c - the residency ladder algorithm
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
+ *
+ * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ *               Shaohua Li <shaohua.li@intel.com>
+ *               Adam Belay <abelay@novell.com>
+ *
+ * This code is licenced under the GPL.
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpuidle.h>
+#include <linux/jiffies.h>
+#include <linux/tick.h>
+
+#include <asm/io.h>
+#include <linux/uaccess.h>
+
+#define PROMOTION_COUNT 4
+#define DEMOTION_COUNT 1
+
+struct ladder_device_state {
+	struct {
+		u32 promotion_count;
+		u32 demotion_count;
+		u64 promotion_time_ns;
+		u64 demotion_time_ns;
+	} threshold;
+	struct {
+		int promotion_count;
+		int demotion_count;
+	} stats;
+};
+
+struct ladder_device {
+	struct ladder_device_state states[CPUIDLE_STATE_MAX];
+};
+
+static DEFINE_PER_CPU(struct ladder_device, ladder_devices);
+
+/**
+ * ladder_do_selection - prepares private data for a state change
+ * @ldev: the ladder device
+ * @old_idx: the current state index
+ * @new_idx: the new target state index
+ */
+static inline void ladder_do_selection(struct cpuidle_device *dev,
+				       struct ladder_device *ldev,
+				       int old_idx, int new_idx)
+{
+	ldev->states[old_idx].stats.promotion_count = 0;
+	ldev->states[old_idx].stats.demotion_count = 0;
+	dev->last_state_idx = new_idx;
+}
+
+/**
+ * ladder_select_state - selects the next state to enter
+ * @drv: cpuidle driver
+ * @dev: the CPU
+ * @dummy: not used
+ */
+static int ladder_select_state(struct cpuidle_driver *drv,
+			       struct cpuidle_device *dev, bool *dummy)
+{
+	struct ladder_device *ldev = this_cpu_ptr(&ladder_devices);
+	struct ladder_device_state *last_state;
+	int last_idx = dev->last_state_idx;
+	int first_idx = drv->states[0].flags & CPUIDLE_FLAG_POLLING ? 1 : 0;
+	s64 latency_req = cpuidle_governor_latency_req(dev->cpu);
+	s64 last_residency;
+
+	/* Special case when user has set very strict latency requirement */
+	if (unlikely(latency_req == 0)) {
+		ladder_do_selection(dev, ldev, last_idx, 0);
+		return 0;
+	}
+
+	last_state = &ldev->states[last_idx];
+
+	last_residency = dev->last_residency_ns - drv->states[last_idx].exit_latency_ns;
+
+	/* consider promotion */
+	if (last_idx < drv->state_count - 1 &&
+	    !dev->states_usage[last_idx + 1].disable &&
+	    last_residency > last_state->threshold.promotion_time_ns &&
+	    drv->states[last_idx + 1].exit_latency_ns <= latency_req) {
+		last_state->stats.promotion_count++;
+		last_state->stats.demotion_count = 0;
+		if (last_state->stats.promotion_count >= last_state->threshold.promotion_count) {
+			ladder_do_selection(dev, ldev, last_idx, last_idx + 1);
+			return last_idx + 1;
+		}
+	}
+
+	/* consider demotion */
+	if (last_idx > first_idx &&
+	    (dev->states_usage[last_idx].disable ||
+	    drv->states[last_idx].exit_latency_ns > latency_req)) {
+		int i;
+
+		for (i = last_idx - 1; i > first_idx; i--) {
+			if (drv->states[i].exit_latency_ns <= latency_req)
+				break;
+		}
+		ladder_do_selection(dev, ldev, last_idx, i);
+		return i;
+	}
+
+	if (last_idx > first_idx &&
+	    last_residency < last_state->threshold.demotion_time_ns) {
+		last_state->stats.demotion_count++;
+		last_state->stats.promotion_count = 0;
+		if (last_state->stats.demotion_count >= last_state->threshold.demotion_count) {
+			ladder_do_selection(dev, ldev, last_idx, last_idx - 1);
+			return last_idx - 1;
+		}
+	}
+
+	/* otherwise remain at the current state */
+	return last_idx;
+}
+
+/**
+ * ladder_enable_device - setup for the governor
+ * @drv: cpuidle driver
+ * @dev: the CPU
+ */
+static int ladder_enable_device(struct cpuidle_driver *drv,
+				struct cpuidle_device *dev)
+{
+	int i;
+	int first_idx = drv->states[0].flags & CPUIDLE_FLAG_POLLING ? 1 : 0;
+	struct ladder_device *ldev = &per_cpu(ladder_devices, dev->cpu);
+	struct ladder_device_state *lstate;
+	struct cpuidle_state *state;
+
+	dev->last_state_idx = first_idx;
+
+	for (i = first_idx; i < drv->state_count; i++) {
+		state = &drv->states[i];
+		lstate = &ldev->states[i];
+
+		lstate->stats.promotion_count = 0;
+		lstate->stats.demotion_count = 0;
+
+		lstate->threshold.promotion_count = PROMOTION_COUNT;
+		lstate->threshold.demotion_count = DEMOTION_COUNT;
+
+		if (i < drv->state_count - 1)
+			lstate->threshold.promotion_time_ns = state->exit_latency_ns;
+		if (i > first_idx)
+			lstate->threshold.demotion_time_ns = state->exit_latency_ns;
+	}
+
+	return 0;
+}
+
+/**
+ * ladder_reflect - update the correct last_state_idx
+ * @dev: the CPU
+ * @index: the index of actual state entered
+ */
+static void ladder_reflect(struct cpuidle_device *dev, int index)
+{
+	if (index > 0)
+		dev->last_state_idx = index;
+}
+
+static struct cpuidle_governor ladder_governor = {
+	.name =		"ladder",
+	.rating =	10,
+	.enable =	ladder_enable_device,
+	.select =	ladder_select_state,
+	.reflect =	ladder_reflect,
+};
+
+/**
+ * init_ladder - initializes the governor
+ */
+static int __init init_ladder(void)
+{
+	/*
+	 * When NO_HZ is disabled, or when booting with nohz=off, the ladder
+	 * governor is better so give it a higher rating than the menu
+	 * governor.
+	 */
+	if (!tick_nohz_enabled)
+		ladder_governor.rating = 25;
+
+	return cpuidle_register_governor(&ladder_governor);
+}
+
+postcore_initcall(init_ladder);