PM / devfreq: tegra20: Deprecate in a favor of emc-stat based driver (98fd9972) · Commits · 戴 / test

MAINTAINERS

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		@@ -11339,7 +11339,6 @@ L: linux-pm@vger.kernel.org
		L: linux-tegra@vger.kernel.org
		T: git git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git
		S: Maintained
		F: drivers/devfreq/tegra20-devfreq.c
		F: drivers/devfreq/tegra30-devfreq.c

		MEMORY MANAGEMENT

drivers/devfreq/Kconfig

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		@@ -121,16 +121,6 @@ config ARM_TEGRA_DEVFREQ
		It reads ACTMON counters of memory controllers and adjusts the
		operating frequencies and voltages with OPP support.

		config ARM_TEGRA20_DEVFREQ
		tristate "NVIDIA Tegra20 DEVFREQ Driver"
		depends on ARCH_TEGRA_2x_SOC \|\| COMPILE_TEST
		depends on COMMON_CLK
		select DEVFREQ_GOV_SIMPLE_ONDEMAND
		help
		This adds the DEVFREQ driver for the Tegra20 family of SoCs.
		It reads Memory Controller counters and adjusts the operating
		frequencies and voltages with OPP support.

		config ARM_RK3399_DMC_DEVFREQ
		tristate "ARM RK3399 DMC DEVFREQ Driver"
		depends on (ARCH_ROCKCHIP && HAVE_ARM_SMCCC) \|\| \

drivers/devfreq/Makefile

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		@@ -13,7 +13,6 @@ obj-$(CONFIG_ARM_IMX_BUS_DEVFREQ) += imx-bus.o
		obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o
		obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o
		obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30-devfreq.o
		obj-$(CONFIG_ARM_TEGRA20_DEVFREQ) += tegra20-devfreq.o

		# DEVFREQ Event Drivers
		obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/

drivers/devfreq/tegra20-devfreq.c

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* NVIDIA Tegra20 devfreq driver
		*
		* Copyright (C) 2019 GRATE-DRIVER project
		*/

		#include <linux/clk.h>
		#include <linux/devfreq.h>
		#include <linux/io.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/of_device.h>
		#include <linux/platform_device.h>
		#include <linux/pm_opp.h>
		#include <linux/slab.h>

		#include <soc/tegra/mc.h>

		#include "governor.h"

		#define MC_STAT_CONTROL 0x90
		#define MC_STAT_EMC_CLOCK_LIMIT 0xa0
		#define MC_STAT_EMC_CLOCKS 0xa4
		#define MC_STAT_EMC_CONTROL 0xa8
		#define MC_STAT_EMC_COUNT 0xb8

		#define EMC_GATHER_CLEAR (1 << 8)
		#define EMC_GATHER_ENABLE (3 << 8)

		struct tegra_devfreq {
		struct devfreq *devfreq;
		struct clk *emc_clock;
		void __iomem *regs;
		};

		static int tegra_devfreq_target(struct device dev, unsigned long freq,
		u32 flags)
		{
		struct tegra_devfreq *tegra = dev_get_drvdata(dev);
		struct devfreq *devfreq = tegra->devfreq;
		struct dev_pm_opp *opp;
		unsigned long rate;
		int err;

		opp = devfreq_recommended_opp(dev, freq, flags);
		if (IS_ERR(opp))
		return PTR_ERR(opp);

		rate = dev_pm_opp_get_freq(opp);
		dev_pm_opp_put(opp);

		err = clk_set_min_rate(tegra->emc_clock, rate);
		if (err)
		return err;

		err = clk_set_rate(tegra->emc_clock, 0);
		if (err)
		goto restore_min_rate;

		return 0;

		restore_min_rate:
		clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq);

		return err;
		}

		static int tegra_devfreq_get_dev_status(struct device *dev,
		struct devfreq_dev_status *stat)
		{
		struct tegra_devfreq *tegra = dev_get_drvdata(dev);

		/*
		* EMC_COUNT returns number of memory events, that number is lower
		* than the number of clocks. Conversion ratio of 1/8 results in a
		* bit higher bandwidth than actually needed, it is good enough for
		* the time being because drivers don't support requesting minimum
		* needed memory bandwidth yet.
		*
		* TODO: adjust the ratio value once relevant drivers will support
		* memory bandwidth management.
		*/
		stat->busy_time = readl_relaxed(tegra->regs + MC_STAT_EMC_COUNT);
		stat->total_time = readl_relaxed(tegra->regs + MC_STAT_EMC_CLOCKS) / 8;
		stat->current_frequency = clk_get_rate(tegra->emc_clock);

		writel_relaxed(EMC_GATHER_CLEAR, tegra->regs + MC_STAT_CONTROL);
		writel_relaxed(EMC_GATHER_ENABLE, tegra->regs + MC_STAT_CONTROL);

		return 0;
		}

		static struct devfreq_dev_profile tegra_devfreq_profile = {
		.polling_ms = 500,
		.target = tegra_devfreq_target,
		.get_dev_status = tegra_devfreq_get_dev_status,
		};

		static struct tegra_mc *tegra_get_memory_controller(void)
		{
		struct platform_device *pdev;
		struct device_node *np;
		struct tegra_mc *mc;

		np = of_find_compatible_node(NULL, NULL, "nvidia,tegra20-mc-gart");
		if (!np)
		return ERR_PTR(-ENOENT);

		pdev = of_find_device_by_node(np);
		of_node_put(np);
		if (!pdev)
		return ERR_PTR(-ENODEV);

		mc = platform_get_drvdata(pdev);
		if (!mc)
		return ERR_PTR(-EPROBE_DEFER);

		return mc;
		}

		static int tegra_devfreq_probe(struct platform_device *pdev)
		{
		struct tegra_devfreq *tegra;
		struct tegra_mc *mc;
		unsigned long max_rate;
		unsigned long rate;
		int err;

		mc = tegra_get_memory_controller();
		if (IS_ERR(mc)) {
		err = PTR_ERR(mc);
		dev_err(&pdev->dev, "failed to get memory controller: %d\n",
		err);
		return err;
		}

		tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
		if (!tegra)
		return -ENOMEM;

		/* EMC is a system-critical clock that is always enabled */
		tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
		if (IS_ERR(tegra->emc_clock))
		return dev_err_probe(&pdev->dev, PTR_ERR(tegra->emc_clock),
		"failed to get emc clock\n");

		tegra->regs = mc->regs;

		max_rate = clk_round_rate(tegra->emc_clock, ULONG_MAX);

		for (rate = 0; rate <= max_rate; rate++) {
		rate = clk_round_rate(tegra->emc_clock, rate);

		err = dev_pm_opp_add(&pdev->dev, rate, 0);
		if (err) {
		dev_err(&pdev->dev, "failed to add opp: %d\n", err);
		goto remove_opps;
		}
		}

		/*
		* Reset statistic gathers state, select global bandwidth for the
		* statistics collection mode and set clocks counter saturation
		* limit to maximum.
		*/
		writel_relaxed(0x00000000, tegra->regs + MC_STAT_CONTROL);
		writel_relaxed(0x00000000, tegra->regs + MC_STAT_EMC_CONTROL);
		writel_relaxed(0xffffffff, tegra->regs + MC_STAT_EMC_CLOCK_LIMIT);

		platform_set_drvdata(pdev, tegra);

		tegra->devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
		DEVFREQ_GOV_SIMPLE_ONDEMAND, NULL);
		if (IS_ERR(tegra->devfreq)) {
		err = PTR_ERR(tegra->devfreq);
		goto remove_opps;
		}

		return 0;

		remove_opps:
		dev_pm_opp_remove_all_dynamic(&pdev->dev);

		return err;
		}

		static int tegra_devfreq_remove(struct platform_device *pdev)
		{
		struct tegra_devfreq *tegra = platform_get_drvdata(pdev);

		devfreq_remove_device(tegra->devfreq);
		dev_pm_opp_remove_all_dynamic(&pdev->dev);

		return 0;
		}

		static struct platform_driver tegra_devfreq_driver = {
		.probe = tegra_devfreq_probe,
		.remove = tegra_devfreq_remove,
		.driver = {
		.name = "tegra20-devfreq",
		},
		};
		module_platform_driver(tegra_devfreq_driver);

		MODULE_ALIAS("platform:tegra20-devfreq");
		MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
		MODULE_DESCRIPTION("NVIDIA Tegra20 devfreq driver");
		MODULE_LICENSE("GPL v2");

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