Simple GPU Algorithm: Initial coding for devfreq based Adreno Drivers

This is an open source user configurable simple GPU Control Algorithm used to
replace the closed sourced Qualcomm TrustZone GPU controller

Signed-off-by: Paul Reioux <reioux@gmail.com>

drivers/devfreq/Kconfig

@@ -71,6 +71,12 @@ config DEVFREQ_GOV_MSM_ADRENO_TZ
 	  Sets the frequency using a "on-demand" algorithm.
 	  This governor is unlikely to be useful for other devices.
 
+config SIMPLE_GPU_ALGORITHM
+	bool "Simple GPU algorithm"
+	depends on DEVFREQ_GOV_MSM_ADRENO_TZ
+	help
+	  Simple user configurable GPU controlling algorithm
+
 comment "DEVFREQ Drivers"
 
 config ARM_EXYNOS4_BUS_DEVFREQ

drivers/devfreq/Makefile

@@ -4,6 +4,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
 obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
 obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
 obj-$(CONFIG_DEVFREQ_GOV_MSM_ADRENO_TZ)	+= governor_msm_adreno_tz.o
+obj-$(CONFIG_SIMPLE_GPU_ALGORITHM)	+= simple_gpu_algorithm.o
 
 # DEVFREQ Drivers
 obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos4_bus.o

drivers/devfreq/governor_msm_adreno_tz.c

@@ -80,6 +80,12 @@ static void _update_cutoff(struct devfreq_msm_adreno_tz_data *priv,
 	}
 }
 
+#ifdef CONFIG_SIMPLE_GPU_ALGORITHM
+extern int simple_gpu_active;
+extern int simple_gpu_algorithm(int level,
+				struct devfreq_msm_adreno_tz_data *priv);
+#endif
+
 static int tz_get_target_freq(struct devfreq *devfreq, unsigned long *freq,
 				u32 *flag)
 {
@@ -137,10 +143,20 @@ static int tz_get_target_freq(struct devfreq *devfreq, unsigned long *freq,
 	if (priv->bin.busy_time > CEILING) {
 		val = -1 * level;
 	} else {
+#ifdef CONFIG_SIMPLE_GPU_ALGORITHM
+		if (simple_gpu_active != 0)
+			val = simple_gpu_algorithm(level, priv);
+		else
+			val = __secure_tz_entry3(TZ_UPDATE_ID,
+					level,
+					priv->bin.total_time,
+					priv->bin.busy_time);
+#else
 		val = __secure_tz_entry3(TZ_UPDATE_ID,
 				level,
 				priv->bin.total_time,
 				priv->bin.busy_time);
+#endif
 	}
 	priv->bin.total_time = 0;
 	priv->bin.busy_time = 0;

drivers/devfreq/simple_gpu_algorithm.c

@@ -0,0 +1,77 @@
+/*
+ * Author: Paul Reioux aka Faux123 <reioux@gmail.com>
+ *
+ * Copyright 2011~2014 Paul Reioux
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/module.h>
+#include <linux/devfreq.h>
+#include <linux/msm_adreno_devfreq.h>
+
+static int default_laziness = 4;
+module_param_named(simple_laziness, default_laziness, int, 0664);
+
+static int ramp_up_threshold = 5000;
+module_param_named(simple_ramp_threshold, ramp_up_threshold, int, 0664);
+
+int simple_gpu_active = 0;
+module_param_named(simple_gpu_activate, simple_gpu_active, int, 0664);
+
+static int laziness;
+
+int simple_gpu_algorithm(int level,
+			struct devfreq_msm_adreno_tz_data *priv)
+{
+	int val;
+
+	/* it's currently busy */
+	if (priv->bin.busy_time > ramp_up_threshold) {
+		if (level == 0)
+			val = 0; /* already maxed, so do nothing */
+		else if ((level > 0) &&
+			(level <= (priv->bus.num - 1)))
+			val = -1; /* bump up to next pwrlevel */
+	/* idle case */
+	} else {
+		if ((level >= 0) &&
+			(level < (priv->bus.num - 1)))
+			if (laziness > 0) {
+				/* hold off for a while */
+				laziness--;
+				val = 0; /* don't change anything yet */
+			} else {
+				val = 1; /* above min, lower it */
+				/* reset laziness count */
+				laziness = default_laziness;
+		} else if (level == (priv->bus.num - 1))
+			val = 0; /* already @ min, so do nothing */
+	}
+	return val;
+}
+EXPORT_SYMBOL(simple_gpu_algorithm);
+
+static int __init simple_gpu_init(void)
+{
+	return 0;
+}
+subsys_initcall(simple_gpu_init);
+
+static void __exit simple_gpu_exit(void)
+{
+	return;
+}
+module_exit(simple_gpu_exit);
+
+MODULE_AUTHOR("Paul Reioux <reioux@gmail.com>");
+MODULE_DESCRIPTION("'simple_gpu_algorithm - A Simple user configurable GPU"
+	"Control Algorithm for Adreno GPU series");
+MODULE_LICENSE("GPL");