msm: kgsl: Set DDR qos level based on GPU bus IB vote

For the highest IB vote, enable DDR qos level which increases
performance by disabling certain DDR low power states.

Change-Id: Iaabc99f724ca6f2b8de2a95da00f73608209e97f
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>

drivers/gpu/msm/adreno_a6xx.c

@@ -129,6 +129,36 @@ static void a6xx_gmu_wrapper_init(struct adreno_device *adreno_dev)
 		dev_warn(device->dev, "gmu_wrapper ioremap failed\n");
 }
 
+static int match_name(struct device *dev, void *data)
+{
+	struct device *parent = data;
+
+	return (!strcmp(dev_name(dev), dev_name(parent)));
+}
+
+static void find_ddr_qos_device(struct adreno_device *adreno_dev)
+{
+	struct device *devfreq_dev, *ddr_qos_dev;
+	struct kgsl_device *device = KGSL_DEVICE(adreno_dev);
+
+	if (device->pwrctrl.ddr_qos_devfreq)
+		return;
+
+	ddr_qos_dev = bus_find_device_by_name(&platform_bus_type, NULL,
+			"soc:qcom,kgsl-ddr-qos");
+
+	if (!ddr_qos_dev)
+		return;
+
+	/* Devfreq device has the same name as its parent device */
+	devfreq_dev = device_find_child(ddr_qos_dev, ddr_qos_dev, match_name);
+	if (!devfreq_dev)
+		return;
+
+	device->pwrctrl.ddr_qos_devfreq = container_of(devfreq_dev,
+					struct devfreq, dev);
+}
+
 int a6xx_init(struct adreno_device *adreno_dev)
 {
 	const struct adreno_a6xx_core *a6xx_core = to_a6xx_core(adreno_dev);
@@ -157,6 +187,8 @@ int a6xx_init(struct adreno_device *adreno_dev)
 			return PTR_ERR(adreno_dev->pwrup_reglist);
 	}
 
+	find_ddr_qos_device(adreno_dev);
+
 	return a6xx_get_cp_init_cmds(adreno_dev);
 }
 

drivers/gpu/msm/kgsl_bus.c

@@ -5,7 +5,9 @@
 
 #include <linux/interconnect.h>
 #include <linux/of.h>
+#include <linux/devfreq.h>
 
+#include "../../devfreq/governor.h"
 #include "kgsl_bus.h"
 #include "kgsl_device.h"
 #include "kgsl_trace.h"
@@ -30,6 +32,36 @@ static u32 _ab_buslevel_update(struct kgsl_pwrctrl *pwr,
 	return (pwr->bus_percent_ab * pwr->bus_max) / 100;
 }
 
+static void set_ddr_qos(struct kgsl_device *device, int buslevel)
+{
+	struct kgsl_pwrctrl *pwr = &device->pwrctrl;
+	struct devfreq *dev = pwr->ddr_qos_devfreq;
+	static unsigned long cur_min_freq;
+	unsigned long new_min_freq = DEVFREQ_MIN_FREQ;
+	int ret;
+
+	if (!dev)
+		return;
+
+	/*
+	 * Instead of creating a new dummy governor, we are using powersave
+	 * governor for this devfreq device. Therefore, modify the minimum
+	 * frequency to point to the desired QOS level.
+	 */
+	if (buslevel == pwr->pwrlevels[0].bus_max)
+		new_min_freq = DEVFREQ_MAX_FREQ;
+
+	if (new_min_freq == cur_min_freq)
+		return;
+
+	mutex_lock(&dev->lock);
+	dev->min_freq = new_min_freq;
+	ret = update_devfreq(dev);
+	mutex_unlock(&dev->lock);
+
+	if (!ret)
+		cur_min_freq = new_min_freq;
+}
 
 int kgsl_bus_update(struct kgsl_device *device,
 			 enum kgsl_bus_vote vote_state)
@@ -37,7 +69,7 @@ int kgsl_bus_update(struct kgsl_device *device,
 	struct kgsl_pwrctrl *pwr = &device->pwrctrl;
 	/* FIXME: this might be wrong? */
 	int cur = pwr->pwrlevels[pwr->active_pwrlevel].bus_freq;
-	int buslevel = 0;
+	int ret, buslevel = 0;
 	u32 ab;
 
 	/* the bus should be ON to update the active frequency */
@@ -68,7 +100,13 @@ int kgsl_bus_update(struct kgsl_device *device,
 	/* buslevel is the IB vote, update the AB */
 	ab = _ab_buslevel_update(pwr, pwr->ddr_table[buslevel]);
 
-	return device->ftbl->gpu_bus_set(device, buslevel, ab);
+	ret = device->ftbl->gpu_bus_set(device, buslevel, ab);
+	if (ret)
+		return ret;
+
+	set_ddr_qos(device, buslevel);
+
+	return 0;
 }
 
 static void validate_pwrlevels(struct kgsl_device *device, u32 *ibs,
@@ -175,4 +213,6 @@ void kgsl_bus_close(struct kgsl_device *device)
 	kfree(device->pwrctrl.ddr_table);
 	device->pwrctrl.ddr_table = NULL;
 	icc_put(device->pwrctrl.icc_path);
+	if (device->pwrctrl.ddr_qos_devfreq)
+		put_device(&device->pwrctrl.ddr_qos_devfreq->dev);
 }

drivers/gpu/msm/kgsl_pwrctrl.h

@@ -169,6 +169,8 @@ struct kgsl_pwrctrl {
 	struct timer_list minbw_timer;
 	/** @minbw_timeout - Timeout for entering minimum bandwidth state */
 	u32 minbw_timeout;
+	/** @ddr_qos_devfreq: Devfreq device for setting DDR qos policy */
+	struct devfreq *ddr_qos_devfreq;
 };
 
 int kgsl_pwrctrl_init(struct kgsl_device *device);