PM / devfreq: Add Exynos5-bus devfreq driver for Exynos5250

Exynos5-bus device devfreq driver monitors PPMU counters and
adjusts operating frequencies and voltages with OPP. ASV should
be used to provide appropriate voltages as per the speed group
of the SoC rather than using a constant 1.025V.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
[myungjoo.ham@samsung.com: minor style update]
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Jonghwan Choi <jhbird.choi@samsung.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>

Change-Id: I9cfb1f88fc61623425f34013d7c0f3a9bb474c55

1 files changed, 500 insertions, 0 deletions

diff --git a/drivers/devfreq/exynos/exynos5_bus.c b/drivers/devfreq/exynos/exynos5_bus.c
new file mode 100644
index 00000000000..0ba86c79190
--- /dev/null
+++ b/drivers/devfreq/exynos/exynos5_bus.c
@@ -0,0 +1,500 @@
+/*
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com/
+ *
+ * EXYNOS5 INT clock frequency scaling support using DEVFREQ framework
+ * Based on work done by Jonghwan Choi <jhbird.choi@samsung.com>
+ * Support for only EXYNOS5250 is present.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/devfreq.h>
+#include <linux/io.h>
+#include <linux/opp.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/pm_qos.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#include "exynos_ppmu.h"
+
+#define MAX_SAFEVOLT			1100000 /* 1.10V */
+/* Assume that the bus is saturated if the utilization is 25% */
+#define INT_BUS_SATURATION_RATIO	25
+
+enum int_level_idx {
+	LV_0,
+	LV_1,
+	LV_2,
+	LV_3,
+	LV_4,
+	_LV_END
+};
+
+enum exynos_ppmu_list {
+	PPMU_RIGHT,
+	PPMU_END,
+};
+
+struct busfreq_data_int {
+	struct device *dev;
+	struct devfreq *devfreq;
+	struct regulator *vdd_int;
+	struct exynos_ppmu ppmu[PPMU_END];
+	unsigned long curr_freq;
+	bool disabled;
+
+	struct notifier_block pm_notifier;
+	struct mutex lock;
+	struct pm_qos_request int_req;
+	struct clk *int_clk;
+};
+
+struct int_bus_opp_table {
+	unsigned int idx;
+	unsigned long clk;
+	unsigned long volt;
+};
+
+static struct int_bus_opp_table exynos5_int_opp_table[] = {
+	{LV_0, 266000, 1025000},
+	{LV_1, 200000, 1025000},
+	{LV_2, 160000, 1025000},
+	{LV_3, 133000, 1025000},
+	{LV_4, 100000, 1025000},
+	{0, 0, 0},
+};
+
+static void busfreq_mon_reset(struct busfreq_data_int *data)
+{
+	unsigned int i;
+
+	for (i = PPMU_RIGHT; i < PPMU_END; i++) {
+		void __iomem *ppmu_base = data->ppmu[i].hw_base;
+
+		/* Reset the performance and cycle counters */
+		exynos_ppmu_reset(ppmu_base);
+
+		/* Setup count registers to monitor read/write transactions */
+		data->ppmu[i].event[PPMU_PMNCNT3] = RDWR_DATA_COUNT;
+		exynos_ppmu_setevent(ppmu_base, PPMU_PMNCNT3,
+					data->ppmu[i].event[PPMU_PMNCNT3]);
+
+		exynos_ppmu_start(ppmu_base);
+	}
+}
+
+static void exynos5_read_ppmu(struct busfreq_data_int *data)
+{
+	int i, j;
+
+	for (i = PPMU_RIGHT; i < PPMU_END; i++) {
+		void __iomem *ppmu_base = data->ppmu[i].hw_base;
+
+		exynos_ppmu_stop(ppmu_base);
+
+		/* Update local data from PPMU */
+		data->ppmu[i].ccnt = __raw_readl(ppmu_base + PPMU_CCNT);
+
+		for (j = PPMU_PMNCNT0; j < PPMU_PMNCNT_MAX; j++) {
+			if (data->ppmu[i].event[j] == 0)
+				data->ppmu[i].count[j] = 0;
+			else
+				data->ppmu[i].count[j] =
+					exynos_ppmu_read(ppmu_base, j);
+		}
+	}
+
+	busfreq_mon_reset(data);
+}
+
+static int exynos5_int_setvolt(struct busfreq_data_int *data,
+				unsigned long volt)
+{
+	return regulator_set_voltage(data->vdd_int, volt, MAX_SAFEVOLT);
+}
+
+static int exynos5_busfreq_int_target(struct device *dev, unsigned long *_freq,
+			      u32 flags)
+{
+	int err = 0;
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data_int *data = platform_get_drvdata(pdev);
+	struct opp *opp;
+	unsigned long old_freq, freq;
+	unsigned long volt;
+
+	rcu_read_lock();
+	opp = devfreq_recommended_opp(dev, _freq, flags);
+	if (IS_ERR(opp)) {
+		rcu_read_unlock();
+		dev_err(dev, "%s: Invalid OPP.\n", __func__);
+		return PTR_ERR(opp);
+	}
+
+	freq = opp_get_freq(opp);
+	volt = opp_get_voltage(opp);
+	rcu_read_unlock();
+
+	old_freq = data->curr_freq;
+
+	if (old_freq == freq)
+		return 0;
+
+	dev_dbg(dev, "targeting %lukHz %luuV\n", freq, volt);
+
+	mutex_lock(&data->lock);
+
+	if (data->disabled)
+		goto out;
+
+	if (freq > exynos5_int_opp_table[0].clk)
+		pm_qos_update_request(&data->int_req, freq * 16 / 1000);
+	else
+		pm_qos_update_request(&data->int_req, -1);
+
+	if (old_freq < freq)
+		err = exynos5_int_setvolt(data, volt);
+	if (err)
+		goto out;
+
+	err = clk_set_rate(data->int_clk, freq * 1000);
+
+	if (err)
+		goto out;
+
+	if (old_freq > freq)
+		err = exynos5_int_setvolt(data, volt);
+	if (err)
+		goto out;
+
+	data->curr_freq = freq;
+out:
+	mutex_unlock(&data->lock);
+	return err;
+}
+
+static int exynos5_get_busier_dmc(struct busfreq_data_int *data)
+{
+	int i, j;
+	int busy = 0;
+	unsigned int temp = 0;
+
+	for (i = PPMU_RIGHT; i < PPMU_END; i++) {
+		for (j = PPMU_PMNCNT0; j < PPMU_PMNCNT_MAX; j++) {
+			if (data->ppmu[i].count[j] > temp) {
+				temp = data->ppmu[i].count[j];
+				busy = i;
+			}
+		}
+	}
+
+	return busy;
+}
+
+static int exynos5_int_get_dev_status(struct device *dev,
+				      struct devfreq_dev_status *stat)
+{
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data_int *data = platform_get_drvdata(pdev);
+	int busier_dmc;
+
+	exynos5_read_ppmu(data);
+	busier_dmc = exynos5_get_busier_dmc(data);
+
+	stat->current_frequency = data->curr_freq;
+
+	/* Number of cycles spent on memory access */
+	stat->busy_time = data->ppmu[busier_dmc].count[PPMU_PMNCNT3];
+	stat->busy_time *= 100 / INT_BUS_SATURATION_RATIO;
+	stat->total_time = data->ppmu[busier_dmc].ccnt;
+
+	return 0;
+}
+static void exynos5_int_exit(struct device *dev)
+{
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data_int *data = platform_get_drvdata(pdev);
+
+	devfreq_unregister_opp_notifier(dev, data->devfreq);
+}
+
+static struct devfreq_dev_profile exynos5_devfreq_int_profile = {
+	.initial_freq		= 160000,
+	.polling_ms		= 100,
+	.target			= exynos5_busfreq_int_target,
+	.get_dev_status		= exynos5_int_get_dev_status,
+	.exit			= exynos5_int_exit,
+};
+
+static int exynos5250_init_int_tables(struct busfreq_data_int *data)
+{
+	int i, err = 0;
+
+	for (i = LV_0; i < _LV_END; i++) {
+		err = opp_add(data->dev, exynos5_int_opp_table[i].clk,
+				exynos5_int_opp_table[i].volt);
+		if (err) {
+			dev_err(data->dev, "Cannot add opp entries.\n");
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int exynos5_busfreq_int_pm_notifier_event(struct notifier_block *this,
+		unsigned long event, void *ptr)
+{
+	struct busfreq_data_int *data = container_of(this,
+					struct busfreq_data_int, pm_notifier);
+	struct opp *opp;
+	unsigned long maxfreq = ULONG_MAX;
+	unsigned long freq;
+	unsigned long volt;
+	int err = 0;
+
+	switch (event) {
+	case PM_SUSPEND_PREPARE:
+		/* Set Fastest and Deactivate DVFS */
+		mutex_lock(&data->lock);
+
+		data->disabled = true;
+
+		rcu_read_lock();
+		opp = opp_find_freq_floor(data->dev, &maxfreq);
+		if (IS_ERR(opp)) {
+			rcu_read_unlock();
+			err = PTR_ERR(opp);
+			goto unlock;
+		}
+		freq = opp_get_freq(opp);
+		volt = opp_get_voltage(opp);
+		rcu_read_unlock();
+
+		err = exynos5_int_setvolt(data, volt);
+		if (err)
+			goto unlock;
+
+		err = clk_set_rate(data->int_clk, freq * 1000);
+
+		if (err)
+			goto unlock;
+
+		data->curr_freq = freq;
+unlock:
+		mutex_unlock(&data->lock);
+		if (err)
+			return NOTIFY_BAD;
+		return NOTIFY_OK;
+	case PM_POST_RESTORE:
+	case PM_POST_SUSPEND:
+		/* Reactivate */
+		mutex_lock(&data->lock);
+		data->disabled = false;
+		mutex_unlock(&data->lock);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int exynos5_busfreq_int_probe(struct platform_device *pdev)
+{
+	struct busfreq_data_int *data;
+	struct opp *opp;
+	struct device *dev = &pdev->dev;
+	struct device_node *np;
+	unsigned long initial_freq;
+	unsigned long initial_volt;
+	int err = 0;
+	int i;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(struct busfreq_data_int),
+				GFP_KERNEL);
+	if (data == NULL) {
+		dev_err(dev, "Cannot allocate memory.\n");
+		return -ENOMEM;
+	}
+
+	np = of_find_compatible_node(NULL, NULL, "samsung,exynos5250-ppmu");
+	if (np == NULL) {
+		pr_err("Unable to find PPMU node\n");
+		return -ENOENT;
+	}
+
+	for (i = PPMU_RIGHT; i < PPMU_END; i++) {
+		/* map PPMU memory region */
+		data->ppmu[i].hw_base = of_iomap(np, i);
+		if (data->ppmu[i].hw_base == NULL) {
+			dev_err(&pdev->dev, "failed to map memory region\n");
+			return -ENOMEM;
+		}
+	}
+	data->pm_notifier.notifier_call = exynos5_busfreq_int_pm_notifier_event;
+	data->dev = dev;
+	mutex_init(&data->lock);
+
+	err = exynos5250_init_int_tables(data);
+	if (err)
+		goto err_regulator;
+
+	data->vdd_int = regulator_get(dev, "vdd_int");
+	if (IS_ERR(data->vdd_int)) {
+		dev_err(dev, "Cannot get the regulator \"vdd_int\"\n");
+		err = PTR_ERR(data->vdd_int);
+		goto err_regulator;
+	}
+
+	data->int_clk = clk_get(dev, "int_clk");
+	if (IS_ERR(data->int_clk)) {
+		dev_err(dev, "Cannot get clock \"int_clk\"\n");
+		err = PTR_ERR(data->int_clk);
+		goto err_clock;
+	}
+
+	rcu_read_lock();
+	opp = opp_find_freq_floor(dev,
+			&exynos5_devfreq_int_profile.initial_freq);
+	if (IS_ERR(opp)) {
+		rcu_read_unlock();
+		dev_err(dev, "Invalid initial frequency %lu kHz.\n",
+		       exynos5_devfreq_int_profile.initial_freq);
+		err = PTR_ERR(opp);
+		goto err_opp_add;
+	}
+	initial_freq = opp_get_freq(opp);
+	initial_volt = opp_get_voltage(opp);
+	rcu_read_unlock();
+	data->curr_freq = initial_freq;
+
+	err = clk_set_rate(data->int_clk, initial_freq * 1000);
+	if (err) {
+		dev_err(dev, "Failed to set initial frequency\n");
+		goto err_opp_add;
+	}
+
+	err = exynos5_int_setvolt(data, initial_volt);
+	if (err)
+		goto err_opp_add;
+
+	platform_set_drvdata(pdev, data);
+
+	busfreq_mon_reset(data);
+
+	data->devfreq = devfreq_add_device(dev, &exynos5_devfreq_int_profile,
+					   "simple_ondemand", NULL);
+
+	if (IS_ERR(data->devfreq)) {
+		err = PTR_ERR(data->devfreq);
+		goto err_devfreq_add;
+	}
+
+	devfreq_register_opp_notifier(dev, data->devfreq);
+
+	err = register_pm_notifier(&data->pm_notifier);
+	if (err) {
+		dev_err(dev, "Failed to setup pm notifier\n");
+		goto err_devfreq_add;
+	}
+
+	/* TODO: Add a new QOS class for int/mif bus */
+	pm_qos_add_request(&data->int_req, PM_QOS_NETWORK_THROUGHPUT, -1);
+
+	return 0;
+
+err_devfreq_add:
+	devfreq_remove_device(data->devfreq);
+err_opp_add:
+	clk_put(data->int_clk);
+err_clock:
+	regulator_put(data->vdd_int);
+err_regulator:
+	return err;
+}
+
+static int exynos5_busfreq_int_remove(struct platform_device *pdev)
+{
+	struct busfreq_data_int *data = platform_get_drvdata(pdev);
+
+	pm_qos_remove_request(&data->int_req);
+	unregister_pm_notifier(&data->pm_notifier);
+	devfreq_remove_device(data->devfreq);
+	regulator_put(data->vdd_int);
+	clk_put(data->int_clk);
+
+	return 0;
+}
+
+static int exynos5_busfreq_int_resume(struct device *dev)
+{
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data_int *data = platform_get_drvdata(pdev);
+
+	busfreq_mon_reset(data);
+	return 0;
+}
+
+static const struct dev_pm_ops exynos5_busfreq_int_pm = {
+	.resume	= exynos5_busfreq_int_resume,
+};
+
+/* platform device pointer for exynos5 devfreq device. */
+static struct platform_device *exynos5_devfreq_pdev;
+
+static struct platform_driver exynos5_busfreq_int_driver = {
+	.probe		= exynos5_busfreq_int_probe,
+	.remove		= exynos5_busfreq_int_remove,
+	.driver		= {
+		.name		= "exynos5-bus-int",
+		.owner		= THIS_MODULE,
+		.pm		= &exynos5_busfreq_int_pm,
+	},
+};
+
+static int __init exynos5_busfreq_int_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&exynos5_busfreq_int_driver);
+	if (ret < 0)
+		goto out;
+
+	exynos5_devfreq_pdev =
+		platform_device_register_simple("exynos5-bus-int", -1, NULL, 0);
+	if (IS_ERR(exynos5_devfreq_pdev)) {
+		ret = PTR_ERR(exynos5_devfreq_pdev);
+		goto out1;
+	}
+
+	return 0;
+out1:
+	platform_driver_unregister(&exynos5_busfreq_int_driver);
+out:
+	return ret;
+}
+late_initcall(exynos5_busfreq_int_init);
+
+static void __exit exynos5_busfreq_int_exit(void)
+{
+	platform_device_unregister(exynos5_devfreq_pdev);
+	platform_driver_unregister(&exynos5_busfreq_int_driver);
+}
+module_exit(exynos5_busfreq_int_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("EXYNOS5 busfreq driver with devfreq framework");