/*
* A devfreq driver for NVIDIA Tegra SoCs
*
* Copyright (c) 2014 NVIDIA CORPORATION. All rights reserved.
* Copyright (C) 2014 Google, Inc
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/devfreq.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/reset.h>
#include "governor.h"
#define ACTMON_GLB_STATUS 0x0
#define ACTMON_GLB_PERIOD_CTRL 0x4
#define ACTMON_DEV_CTRL 0x0
#define ACTMON_DEV_CTRL_K_VAL_SHIFT 10
#define ACTMON_DEV_CTRL_ENB_PERIODIC BIT(18)
#define ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN BIT(20)
#define ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN BIT(21)
#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT 23
#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT 26
#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN BIT(29)
#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN BIT(30)
#define ACTMON_DEV_CTRL_ENB BIT(31)
#define ACTMON_DEV_UPPER_WMARK 0x4
#define ACTMON_DEV_LOWER_WMARK 0x8
#define ACTMON_DEV_INIT_AVG 0xc
#define ACTMON_DEV_AVG_UPPER_WMARK 0x10
#define ACTMON_DEV_AVG_LOWER_WMARK 0x14
#define ACTMON_DEV_COUNT_WEIGHT 0x18
#define ACTMON_DEV_AVG_COUNT 0x20
#define ACTMON_DEV_INTR_STATUS 0x24
#define ACTMON_INTR_STATUS_CLEAR 0xffffffff
#define ACTMON_DEV_INTR_CONSECUTIVE_UPPER BIT(31)
#define ACTMON_DEV_INTR_CONSECUTIVE_LOWER BIT(30)
#define ACTMON_ABOVE_WMARK_WINDOW 1
#define ACTMON_BELOW_WMARK_WINDOW 3
#define ACTMON_BOOST_FREQ_STEP 16000
/* activity counter is incremented every 256 memory transactions, and each
* transaction takes 4 EMC clocks for Tegra124; So the COUNT_WEIGHT is
* 4 * 256 = 1024.
*/
#define ACTMON_COUNT_WEIGHT 0x400
/*
* ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, which
* translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128
*/
#define ACTMON_AVERAGE_WINDOW_LOG2 6
#define ACTMON_SAMPLING_PERIOD 12 /* ms */
#define ACTMON_DEFAULT_AVG_BAND 6 /* 1/10 of % */
#define KHZ 1000
/* Assume that the bus is saturated if the utilization is 25% */
#define BUS_SATURATION_RATIO 25
/**
* struct tegra_devfreq_device_config - configuration specific to an ACTMON
* device
*
* Coefficients and thresholds are in %
*/
struct tegra_devfreq_device_config {
u32 offset;
u32 irq_mask;
unsigned int boost_up_coeff;
unsigned int boost_down_coeff;
unsigned int boost_up_threshold;
unsigned int boost_down_threshold;
u32 avg_dependency_threshold;
};
enum tegra_actmon_device {
MCALL = 0,
MCCPU,
};
static struct tegra_devfreq_device_config actmon_device_configs[] = {
{
/* MCALL */
.offset = 0x1c0,
.irq_mask = 1 << 26,
.boost_up_coeff = 200,
.boost_down_coeff = 50,
.boost_up_threshold = 60,
.boost_down_threshold = 40,
},
{
/* MCCPU */
.offset = 0x200,
.irq_mask = 1 << 25,
.boost_up_coeff = 800,
.boost_down_coeff = 90,
.boost_up_threshold = 27,
.boost_down_threshold = 10,
.avg_dependency_threshold = 50000,
},
};
/**
* struct tegra_devfreq_device - state specific to an ACTMON device
*
* Frequencies are in kHz.
*/
struct tegra_devfreq_device {
const struct tegra_devfreq_device_config *config;
void __iomem *regs;
u32 avg_band_freq;
u32 avg_count;
unsigned long target_freq;
unsigned long boost_freq;
};
struct tegra_devfreq {
struct devfreq *devfreq;
struct platform_device *pdev;
struct reset_control *reset;
struct clk *clock;
void __iomem *regs;
spinlock_t lock;
struct clk *emc_clock;
unsigned long max_freq;
unsigned long cur_freq;
struct notifier_block rate_change_nb;
struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
};
struct tegra_actmon_emc_ratio {
unsigned long cpu_freq;
unsigned long emc_freq;
};
static struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
{ 1400000, ULONG_MAX },
{ 1200000, 750000 },
{ 1100000, 600000 },
{ 1000000, 500000 },
{ 800000, 375000 },
{ 500000, 200000 },
{ 250000, 100000 },
};
static unsigned long do_percent(unsigned long val, unsigned int pct)
{
return val * pct / 100;
}
static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq_device *dev)
{
u32 avg = dev->avg_count;
u32 band = dev->avg_band_freq * ACTMON_SAMPLING_PERIOD;
writel(avg + band, dev->regs + ACTMON_DEV_AVG_UPPER_WMARK);
avg = max(avg, band);
writel(avg - band, dev->regs + ACTMON_DEV_AVG_LOWER_WMARK);
}
static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
struct tegra_devfreq_device *dev)
{
u32 val = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
writel(do_percent(val, dev->config->boost_up_threshold),
dev->regs + ACTMON_DEV_UPPER_WMARK);
writel(do_percent(val, dev->config->boost_down_threshold),
dev->regs + ACTMON_DEV_LOWER_WMARK);
}
static void actmon_write_barrier(struct tegra_devfreq *tegra)
{
/* ensure the update has reached the ACTMON */
wmb();
readl(tegra->regs + ACTMON_GLB_STATUS);
}
static irqreturn_t actmon_isr(int irq, void *data)
{
struct tegra_devfreq *tegra = data;
struct tegra_devfreq_device *dev = NULL;
unsigned long flags;
u32 val;
unsigned int i;
val = readl(tegra->regs + ACTMON_GLB_STATUS);
for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
if (val & tegra->devices[i].config->irq_mask) {
dev = tegra->devices + i;
break;
}
}
if (!dev)
return IRQ_NONE;
spin_lock_irqsave(&tegra->lock, flags);
dev->avg_count = readl(dev->regs + ACTMON_DEV_AVG_COUNT);
tegra_devfreq_update_avg_wmark(dev);
val = readl(dev->regs + ACTMON_DEV_INTR_STATUS);
if (val & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) {
val = readl(dev->regs + ACTMON_DEV_CTRL) |
ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN |
ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
/*
* new_boost = min(old_boost * up_coef + step, max_freq)
*/
dev->boost_freq = do_percent(dev->boost_freq,
dev->config->boost_up_coeff);
dev->boost_freq += ACTMON_BOOST_FREQ_STEP;
if (dev->boost_freq >= tegra->max_freq) {
dev->boost_freq = tegra->max_freq;
val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
}
writel(val, dev->regs + ACTMON_DEV_CTRL);
} else if (val & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
val = readl(dev->regs + ACTMON_DEV_CTRL) |
ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN |
ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
/*
* new_boost = old_boost * down_coef
* or 0 if (old_boost * down_coef < step / 2)
*/
dev->boost_freq = do_percent(dev->boost_freq,
dev->config->boost_down_coeff);
if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1)) {
dev->boost_freq = 0;
val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
}
writel(val, dev->regs + ACTMON_DEV_CTRL);
}
if (dev->config->avg_dependency_threshold) {
val = readl(dev->regs + ACTMON_DEV_CTRL);
if (dev->avg_count >= dev->config->avg_dependency_threshold)
val |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
else if (dev->boost_freq == 0)
val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
writel(val, dev->regs + ACTMON_DEV_CTRL);
}
writel(ACTMON_INTR_STATUS_CLEAR, dev->regs + ACTMON_DEV_INTR_STATUS);
actmon_write_barrier(tegra);
spin_unlock_irqrestore(&tegra->lock, flags);
return IRQ_WAKE_THREAD;
}
static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
unsigned long cpu_freq)
{
unsigned int i;
struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, ratio++) {
if (cpu_freq >= ratio->cpu_freq) {
if (ratio->emc_freq >= tegra->max_freq)
return tegra->max_freq;
else
return ratio->emc_freq;
}
}
return 0;
}
static void actmon_update_target(struct tegra_devfreq *tegra,
struct tegra_devfreq_device *dev)
{
unsigned long cpu_freq = 0;
unsigned long static_cpu_emc_freq = 0;
unsigned int avg_sustain_coef;
unsigned long flags;
if (dev->config->avg_dependency_threshold) {
cpu_freq = cpufreq_get(0);
static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
}
spin_lock_irqsave(&tegra->lock, flags);
dev->target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD;
avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
dev->target_freq = do_percent(dev->target_freq, avg_sustain_coef);
dev->target_freq += dev->boost_freq;
if (dev->avg_count >= dev->config->avg_dependency_threshold)
dev->target_freq = max(dev->target_freq, static_cpu_emc_freq);
spin_unlock_irqrestore(&tegra->lock, flags);
}
static irqreturn_t actmon_thread_isr(int irq, void *data)
{
struct tegra_devfreq *tegra = data;
mutex_lock(&tegra->devfreq->lock);
update_devfreq(tegra->devfreq);
mutex_unlock(&tegra->devfreq->lock);
return IRQ_HANDLED;
}
static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
unsigned long action, void *ptr)
{
struct clk_notifier_data *data = ptr;
struct tegra_devfreq *tegra = container_of(nb, struct tegra_devfreq,
rate_change_nb);
unsigned int i;
unsigned long flags;
spin_lock_irqsave(&tegra->lock, flags);
switch (action) {
case POST_RATE_CHANGE:
tegra->cur_freq = data->new_rate / KHZ;
for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
tegra_devfreq_update_wmark(tegra, tegra->devices + i);
actmon_write_barrier(tegra);
break;
case PRE_RATE_CHANGE:
/* fall through */
case ABORT_RATE_CHANGE:
break;
};
spin_unlock_irqrestore(&tegra->lock, flags);
return NOTIFY_OK;
}
static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
struct tegra_devfreq_device *dev)
{
u32 val;
dev->avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
dev->target_freq = tegra->cur_freq;
dev->avg_count = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
writel(dev->avg_count, dev->regs + ACTMON_DEV_INIT_AVG);
tegra_devfreq_update_avg_wmark(dev);
tegra_devfreq_update_wmark(tegra, dev);
writel(ACTMON_COUNT_WEIGHT, dev->regs + ACTMON_DEV_COUNT_WEIGHT);
writel(ACTMON_INTR_STATUS_CLEAR, dev->regs + ACTMON_DEV_INTR_STATUS);
val = 0;
val |= ACTMON_DEV_CTRL_ENB_PERIODIC |
ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN |
ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
val |= (ACTMON_AVERAGE_WINDOW_LOG2 - 1)
<< ACTMON_DEV_CTRL_K_VAL_SHIFT;
val |= (ACTMON_BELOW_WMARK_WINDOW - 1)
<< ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT;
val |= (ACTMON_ABOVE_WMARK_WINDOW - 1)
<< ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT;
val |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN |
ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
writel(val, dev->regs + ACTMON_DEV_CTRL);
actmon_write_barrier(tegra);
val = readl(dev->regs + ACTMON_DEV_CTRL);
val |= ACTMON_DEV_CTRL_ENB;
writel(val, dev->regs + ACTMON_DEV_CTRL);
actmon_write_barrier(tegra);
}
static int tegra_devfreq_suspend(struct device *dev)
{
struct platform_device *pdev;
struct tegra_devfreq *tegra;
struct tegra_devfreq_device *actmon_dev;
unsigned int i;
u32 val;
pdev = container_of(dev, struct platform_device, dev);
tegra = platform_get_drvdata(pdev);
for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
actmon_dev = &tegra->devices[i];
val = readl(actmon_dev->regs + ACTMON_DEV_CTRL);
val &= ~ACTMON_DEV_CTRL_ENB;
writel(val, actmon_dev->regs + ACTMON_DEV_CTRL);
writel(ACTMON_INTR_STATUS_CLEAR,
actmon_dev->regs + ACTMON_DEV_INTR_STATUS);
actmon_write_barrier(tegra);
}
return 0;
}
static int tegra_devfreq_resume(struct device *dev)
{
struct platform_device *pdev;
struct tegra_devfreq *tegra;
struct tegra_devfreq_device *actmon_dev;
unsigned int i;
pdev = container_of(dev, struct platform_device, dev);
tegra = platform_get_drvdata(pdev);
for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
actmon_dev = &tegra->devices[i];
tegra_actmon_configure_device(tegra, actmon_dev);
}
return 0;
}
static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
u32 flags)
{
struct platform_device *pdev;
struct tegra_devfreq *tegra;
struct dev_pm_opp *opp;
unsigned long rate = *freq * KHZ;
pdev = container_of(dev, struct platform_device, dev);
tegra = platform_get_drvdata(pdev);
rcu_read_lock();
opp = devfreq_recommended_opp(dev, &rate, flags);
if (IS_ERR(opp)) {
rcu_read_unlock();
dev_err(dev, "Failed to find opp for %lu KHz\n", *freq);
return PTR_ERR(opp);
}
rate = dev_pm_opp_get_freq(opp);
rcu_read_unlock();
/* TODO: Once we have per-user clk constraints, set a floor */
clk_set_rate(tegra->emc_clock, rate);
/* TODO: Set voltage as well */
return 0;
}
static int tegra_devfreq_get_dev_status(struct device *dev,
struct devfreq_dev_status *stat)
{
struct platform_device *pdev;
struct tegra_devfreq *tegra;
struct tegra_devfreq_device *actmon_dev;
pdev = container_of(dev, struct platform_device, dev);
tegra = platform_get_drvdata(pdev);
stat->current_frequency = tegra->cur_freq;
/* To be used by the tegra governor */
stat->private_data = tegra;
/* The below are to be used by the other governors */
actmon_dev = &tegra->devices[MCALL];
/* Number of cycles spent on memory access */
stat->busy_time = actmon_dev->avg_count;
/* The bus can be considered to be saturated way before 100% */
stat->busy_time *= 100 / BUS_SATURATION_RATIO;
/* Number of cycles in a sampling period */
stat->total_time = ACTMON_SAMPLING_PERIOD * tegra->cur_freq;
return 0;
}
static int tegra_devfreq_get_target(struct devfreq *devfreq,
unsigned long *freq)
{
struct devfreq_dev_status stat;
struct tegra_devfreq *tegra;
struct tegra_devfreq_device *dev;
unsigned long target_freq = 0;
unsigned int i;
int err;
err = devfreq->profile->get_dev_status(devfreq->dev.parent, &stat);
if (err)
return err;
tegra = stat.private_data;
for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
dev = &tegra->devices[i];
actmon_update_target(tegra, dev);
target_freq = max(target_freq, dev->target_freq);
}
*freq = target_freq;
return 0;
}
static int tegra_devfreq_event_handler(struct devfreq *devfreq,
unsigned int event, void *data)
{
return 0;
}
static struct devfreq_governor tegra_devfreq_governor = {
.name = "tegra",
.get_target_freq = tegra_devfreq_get_target,
.event_handler = tegra_devfreq_event_handler,
};
static struct devfreq_dev_profile tegra_devfreq_profile = {
.polling_ms = 0,
.target = tegra_devfreq_target,
.get_dev_status = tegra_devfreq_get_dev_status,
};
static int tegra_devfreq_probe(struct platform_device *pdev)
{
struct tegra_devfreq *tegra;
struct tegra_devfreq_device *dev;
struct resource *res;
unsigned long max_freq;
unsigned int i;
int irq;
int err;
tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
if (!tegra)
return -ENOMEM;
spin_lock_init(&tegra->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "Failed to get regs resource\n");
return -ENODEV;
}
tegra->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(tegra->regs)) {
dev_err(&pdev->dev, "Failed to get IO memory\n");
return PTR_ERR(tegra->regs);
}
tegra->reset = devm_reset_control_get(&pdev->dev, "actmon");
if (IS_ERR(tegra->reset)) {
dev_err(&pdev->dev, "Failed to get reset\n");
return PTR_ERR(tegra->reset);
}
tegra->clock = devm_clk_get(&pdev->dev, "actmon");
if (IS_ERR(tegra->clock)) {
dev_err(&pdev->dev, "Failed to get actmon clock\n");
return PTR_ERR(tegra->clock);
}
tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
if (IS_ERR(tegra->emc_clock)) {
dev_err(&pdev->dev, "Failed to get emc clock\n");
return PTR_ERR(tegra->emc_clock);
}
err = of_init_opp_table(&pdev->dev);
if (err) {
dev_err(&pdev->dev, "Failed to init operating point table\n");
return err;
}
tegra->rate_change_nb.notifier_call = tegra_actmon_rate_notify_cb;
err = clk_notifier_register(tegra->emc_clock, &tegra->rate_change_nb);
if (err) {
dev_err(&pdev->dev,
"Failed to register rate change notifier\n");
return err;
}
reset_control_assert(tegra->reset);
err = clk_prepare_enable(tegra->clock);
if (err) {
reset_control_deassert(tegra->reset);
return err;
}
reset_control_deassert(tegra->reset);
max_freq = clk_round_rate(tegra->emc_clock, ULONG_MAX);
tegra->max_freq = max_freq / KHZ;
clk_set_rate(tegra->emc_clock, max_freq);
tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
writel(ACTMON_SAMPLING_PERIOD - 1,
tegra->regs + ACTMON_GLB_PERIOD_CTRL);
for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) {
dev = tegra->devices + i;
dev->config = actmon_device_configs + i;
dev->regs = tegra->regs + dev->config->offset;
tegra_actmon_configure_device(tegra, tegra->devices + i);
}
err = devfreq_add_governor(&tegra_devfreq_governor);
if (err) {
dev_err(&pdev->dev, "Failed to add governor\n");
return err;
}
tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
tegra->devfreq = devm_devfreq_add_device(&pdev->dev,
&tegra_devfreq_profile,
"tegra",
NULL);
irq = platform_get_irq(pdev, 0);
err = devm_request_threaded_irq(&pdev->dev, irq, actmon_isr,
actmon_thread_isr, IRQF_SHARED,
"tegra-devfreq", tegra);
if (err) {
dev_err(&pdev->dev, "Interrupt request failed\n");
return err;
}
platform_set_drvdata(pdev, tegra);
return 0;
}
static int tegra_devfreq_remove(struct platform_device *pdev)
{
struct tegra_devfreq *tegra = platform_get_drvdata(pdev);
clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
clk_disable_unprepare(tegra->clock);
return 0;
}
static SIMPLE_DEV_PM_OPS(tegra_devfreq_pm_ops,
tegra_devfreq_suspend,
tegra_devfreq_resume);
static struct of_device_id tegra_devfreq_of_match[] = {
{ .compatible = "nvidia,tegra124-actmon" },
{ },
};
static struct platform_driver tegra_devfreq_driver = {
.probe = tegra_devfreq_probe,
.remove = tegra_devfreq_remove,
.driver = {
.name = "tegra-devfreq",
.owner = THIS_MODULE,
.of_match_table = tegra_devfreq_of_match,
.pm = &tegra_devfreq_pm_ops,
},
};
module_platform_driver(tegra_devfreq_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Tegra devfreq driver");
MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");
MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);
