| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CAAVeFuKQcstteVi2O2ZE9PWeH9XfCzf9V3jhNnxXn9+1bcW6yA@mail.gmail.com>
Date: Wed, 26 Nov 2014 19:02:07 +0900
From: Alexandre Courbot <gnurou@...il.com>
To: Tomeu Vizoso <tomeu.vizoso@...labora.com>,
Arto Merilainen <amerilainen@...dia.com>
Cc: "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Stephen Warren <swarren@...dotorg.org>,
Thierry Reding <thierry.reding@...il.com>,
Grant Likely <grant.likely@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] PM / devfreq: tegra: add devfreq driver for Tegra
Activity Monitor
On Mon, Nov 24, 2014 at 9:28 PM, Tomeu Vizoso
<tomeu.vizoso@...labora.com> wrote:
> The ACTMON block can monitor several counters, providing averaging and firing
> interrupts based on watermarking configuration. This implementation monitors
> the MCALL and MCCPU counters to choose an appropriate frequency for the
> external memory clock.
>
> This patch is based on work by Alex Frid <afrid@...dia.com> and Mikko
> Perttunen <mikko.perttunen@...si.fi>.
Thanks for taking the time to adapt this driver to use devfreq.
Looking at it, I am more and more convinced that's the correct way to
do.
I made some comments inline, but I'd like to bring Arto Merilainen
into this discussion. Arto thought (and might even have some code)
about adding watermarks support to devfreq's core and using a generic
"watermark" governor which I believe would greatly benefit this patch
set. Arto, do you have some concrete code you could submit here? If
you lack the time for doing so, some guidance so we could implement
this support ourselves would be great.
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>
>
> ---
>
> v2: * Use devfreq
> ---
> drivers/devfreq/Kconfig | 10 +
> drivers/devfreq/Makefile | 1 +
> drivers/devfreq/tegra-devfreq.c | 718 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 729 insertions(+)
> create mode 100644 drivers/devfreq/tegra-devfreq.c
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index faf4e70..4aab799 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -87,4 +87,14 @@ config ARM_EXYNOS5_BUS_DEVFREQ
> It reads PPMU counters of memory controllers and adjusts the
> operating frequencies and voltages with OPP support.
>
> +config ARM_TEGRA_DEVFREQ
> + tristate "Tegra DEVFREQ Driver"
> + depends on ARCH_TEGRA_124_SOC
> + select DEVFREQ_GOV_SIMPLE_ONDEMAND
> + select PM_OPP
> + help
> + This adds the DEVFREQ driver for the Tegra family of SoCs.
> + It reads ACTMON counters of memory controllers and adjusts the
> + operating frequencies and voltages with OPP support.
> +
> endif # PM_DEVFREQ
> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
> index 16138c9..0ea991f 100644
> --- a/drivers/devfreq/Makefile
> +++ b/drivers/devfreq/Makefile
> @@ -7,3 +7,4 @@ obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o
> # DEVFREQ Drivers
> obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ) += exynos/
> obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ) += exynos/
> +obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra-devfreq.o
> diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
> new file mode 100644
> index 0000000..3479096
> --- /dev/null
> +++ b/drivers/devfreq/tegra-devfreq.c
This file should probably be named tegra-actmon-devfreq.c, for nothing
guarantees that we will not have more devfreq devices for Tegra in the
future.
> @@ -0,0 +1,718 @@
> +/*
> + * 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 %
Short comments about what the members are for would be perfect (same
for other structures). It is not immediatly obvious what e.g.
avg_dependency_threshold is for.
> + */
> +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,
The boost_* and avg_dependency_threshold parameters are calling to be
exported through debugfs in some future patch. :)
Just for my education, why do we need to monitor both MCALL and MCCPU,
since MCCPU accesses are included in MCALL? Do we want to boost things
differently in case of CPU activity?
> + },
> +};
> +
> +/**
> + * 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 },
Aren't these numbers board-specific? Should they be moved to the DT maybe?
> +};
> +
> +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);
Having actmon_readl() and actmon_writel() inline functions that make
the "dev->regs +" unnecessary would be nicer to read and less
error-prone IMHO.
> + 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;
Instead of setting this flag to possibly remove it later, maybe set it
only if this condition is not met?
> + }
> + 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;
Same here.
> + }
> + 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:
Can't you use "default:" here instead?
> + 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);
> + }
I *think* you should be able to remove the dependency on
tegra_devfreq_device from this function (ideally, governors should be
device-agnostic). Since you call get_dev_status() from this function
anyway, why not moving the actmon_update_target() calls into
tegra_devfreq_get_dev_status(), and write busy_time/total_time values
that will make tegra_devfreq_get_target() infer the right frequency?
> +
> + *freq = target_freq;
> +
> + return 0;
> +}
> +
> +static int tegra_devfreq_event_handler(struct devfreq *devfreq,
> + unsigned int event, void *data)
> +{
> + return 0;
> +}
I think you will need an implementation of this. Upon
DEVFREQ_GOV_START/DEVFREQ_GOV_RESUME, enable actmon interrupts. On
DEVFREQ_GOV_STOP/DEVFREQ_GOV_SUSPEND, disable interrupts. I know you
are doing it somewhere, but it should be done here as this is what
devfreq expects (e.g. to correctly stop interrupts if you switch from
the "tegra" to the "performance" governor).
Sadly, this adds the exact same dependency on tegra_devfreq that I
tried to remove from the previous function, which is unfortunate. This
is where watermarking support in devfreq would be useful - when
starting the governor, we could ask the device to monitor some low and
high marks through new hooks and handle all this nicely.
> +
> +static struct devfreq_governor tegra_devfreq_governor = {
> + .name = "tegra",
This governor could certainly get a more specific name. :P
> + .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,
> +};
Maybe move this declaration right after the declaration of
tegra_devfreq_get_dev_status() to make things easier to put together
in the reader's mind.
> +
> +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);
This should probably be done in an initcall (that would be executed
before probe() is called). We can in theory have several instances of
ACTMON, but the governor should only be added once in all cases. I
understand that this is unlikely to happen in practice though.
> + 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",
I think "tegra_actmon" would look better here. :)
> + 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);
You probably ought to do this *before* adding the devfreq device,
otherwise you are at risk of receiving interrupts nobody will handle.
> + if (err) {
> + dev_err(&pdev->dev, "Interrupt request failed\n");
> + return err;
> + }
> +
> + platform_set_drvdata(pdev, tegra);
This should also be done before the call to devfreq_add_device().
> +
> + 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);
There seems to be a lot missing in this function, like removing the
devfreq device?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists