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/*
* 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 percentages unless otherwise noted
*/
struct tegra_devfreq_device_config {
u32 offset;
u32 irq_mask;
/* Factors applied to boost_freq every consecutive watermark breach */
unsigned int boost_up_coeff;
unsigned int boost_down_coeff;
/* Define the watermark bounds when applied to the current avg */
unsigned int boost_up_threshold;
unsigned int boost_down_threshold;
/*
* Threshold of activity (cycles) below which the CPU frequency isn't
* to be taken into account. This is to avoid increasing the EMC
* frequency when the CPU is very busy but not accessing the bus often.
*/
u32 avg_dependency_threshold;
};
enum tegra_actmon_device {
MCALL = 0,
MCCPU,
};
static struct tegra_devfreq_device_config actmon_device_configs[] = {
{
/* MCALL: All memory accesses (including from the CPUs) */
.offset = 0x1c0,
.irq_mask = 1 << 26,
.boost_up_coeff = 200,
.boost_down_coeff = 50,
.boost_up_threshold = 60,
.boost_down_threshold = 40,
},
{
/* MCCPU: memory accesses from the CPUs */
.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;
spinlock_t lock;
/* Average event count sampled in the last interrupt */
u32 avg_count;
/*
* Extra frequency to increase the target by due to consecutive
* watermark breaches.
*/
unsigned long boost_freq;
/* Optimal frequency calculated from the stats for this device */
unsigned long target_freq;
};
struct tegra_devfreq {
struct devfreq *devfreq;
struct reset_control *reset;
struct clk *clock;
void __iomem *regs;
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 u32 actmon_readl(struct tegra_devfreq *tegra, u32 offset)
{
return readl(tegra->regs + offset);
}
static void actmon_writel(struct tegra_devfreq *tegra, u32 val, u32 offset)
{
writel(val, tegra->regs + offset);
}
static u32 device_readl(struct tegra_devfreq_device *dev, u32 offset)
{
return readl(dev->regs + offset);
}
static void device_writel(struct tegra_devfreq_device *dev, u32 val,
u32 offset)
{
writel(val, dev->regs + offset);
}
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 *tegra,
struct tegra_devfreq_device *dev)
{
u32 avg = dev->avg_count;
u32 avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
u32 band = avg_band_freq * ACTMON_SAMPLING_PERIOD;
device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK);
avg = max(dev->avg_count, band);
device_writel(dev, avg - band, 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;
device_writel(dev, do_percent(val, dev->config->boost_up_threshold),
ACTMON_DEV_UPPER_WMARK);
device_writel(dev, do_percent(val, dev->config->boost_down_threshold),
ACTMON_DEV_LOWER_WMARK);
}
static void actmon_write_barrier(struct tegra_devfreq *tegra)
{
/* ensure the update has reached the ACTMON */
wmb();
actmon_readl(tegra, ACTMON_GLB_STATUS);
}
static void actmon_isr_device(struct tegra_devfreq *tegra,
struct tegra_devfreq_device *dev)
{
unsigned long flags;
u32 intr_status, dev_ctrl;
spin_lock_irqsave(&dev->lock, flags);
dev->avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT);
tegra_devfreq_update_avg_wmark(tegra, dev);
intr_status = device_readl(dev,
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