On 26 November 2014 at 11:02, Alexandre Courbot <gnurou@xxxxxxxxx> wrote: > On Mon, Nov 24, 2014 at 9:28 PM, Tomeu Vizoso > <tomeu.vizoso@xxxxxxxxxxxxx> 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@xxxxxxxxxx> and Mikko >> Perttunen <mikko.perttunen@xxxxxxxx>. > > 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. Do you know of any other SoC family that would be able to use that code? > 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@xxxxxxxxxxxxx> >> >> --- >> >> 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. Good point. >> @@ -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. Fair enough. >> + */ >> +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? Yeah, I started by using only MCALL and found that performance decreased substantially in scenarios with high CPU loads. Once I took into account CPU frequency and the MCCPU counters as per downstream, performance improved greatly. I cannot tell why MCALL isn't enough though, maybe you can find a fellow NVIDIAn that knows about it? Couldn't find anything in the public TRM about it. >> + }, >> +}; >> + >> +/** >> + * 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? I would expect it to be common to all boards with the same SoC. >> +}; >> + >> +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. Will try that. >> + 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? That sounds better indeed, thanks. >> + } >> + 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? Yeah, this needs simplifying. >> + 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. Wonder if the devfreq maintainers have an opinion on this. >> + >> +static struct devfreq_governor tegra_devfreq_governor = { >> + .name = "tegra", > > This governor could certainly get a more specific name. :P Fair. >> + .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. Agreed. >> + >> +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. Will look at this. >> + 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. :) Agreed. >> + 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. I don't get this one. The IRQ is requested as soon as everything is in place to handle it. >> + 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(). Shouldn't this be done between devfreq_add_device and devm_request_threaded_irq? Guess I'm missing something. >> + >> + 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? Those resources are managed, so devm should take care of releasing them. Thanks, Tomeu > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
