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Message-Id: <20190411223653.27322-1-digetx@gmail.com>
Date: Fri, 12 Apr 2019 01:36:53 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Thierry Reding <thierry.reding@...il.com>,
Jonathan Hunter <jonathanh@...dia.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Chanwoo Choi <cw00.choi@...sung.com>
Cc: linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org
Subject: [PATCH v1] PM / devfreq: Introduce driver for NVIDIA Tegra20
Add devfreq driver for NVIDIA Tegra20 SoC's. The driver periodically
reads out Memory Controller counters and adjusts memory frequency based
on the memory clients activity.
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
MAINTAINERS | 8 ++
drivers/devfreq/Kconfig | 10 ++
drivers/devfreq/Makefile | 1 +
drivers/devfreq/tegra20-devfreq.c | 177 ++++++++++++++++++++++++++++++
4 files changed, 196 insertions(+)
create mode 100644 drivers/devfreq/tegra20-devfreq.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 80b59db1b6e4..91f475ec4545 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10056,6 +10056,14 @@ F: include/linux/memblock.h
F: mm/memblock.c
F: Documentation/core-api/boot-time-mm.rst
+MEMORY FREQUENCY SCALING DRIVER FOR NVIDIA TEGRA20
+M: Dmitry Osipenko <digetx@...il.com>
+L: linux-pm@...r.kernel.org
+L: linux-tegra@...r.kernel.org
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/mzx/devfreq.git
+S: Maintained
+F: drivers/devfreq/tegra20-devfreq.c
+
MEMORY MANAGEMENT
L: linux-mm@...ck.org
W: http://www.linux-mm.org
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 6bae9688a52b..c2a1f791ca86 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -101,6 +101,16 @@ 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 "Tegra20 DEVFREQ Driver"
+ depends on TEGRA_MC && TEGRA20_EMC
+ select DEVFREQ_GOV_SIMPLE_ONDEMAND
+ select PM_OPP
+ 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
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 32b8d4d3f12c..6fcc5596b8b7 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o
obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o
obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o
obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra-devfreq.o
+obj-$(CONFIG_ARM_TEGRA20_DEVFREQ) += tegra20-devfreq.o
# DEVFREQ Event Drivers
obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/
diff --git a/drivers/devfreq/tegra20-devfreq.c b/drivers/devfreq/tegra20-devfreq.c
new file mode 100644
index 000000000000..18c9aad7a9d7
--- /dev/null
+++ b/drivers/devfreq/tegra20-devfreq.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVIDIA Tegra20 devfreq driver
+ *
+ * Author: Dmitry Osipenko <digetx@...il.com>
+ */
+
+#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 *clk;
+ 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 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->clk, rate);
+ if (err)
+ return err;
+
+ err = clk_set_rate(tegra->clk, 0);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static int tegra_devfreq_get_dev_status(struct device *dev,
+ struct devfreq_dev_status *stat)
+{
+ struct tegra_devfreq *tegra = dev_get_drvdata(dev);
+
+ 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->clk);
+
+ 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_devfeq_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 mc: %d\n", err);
+ return err;
+ }
+
+ tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
+ if (!tegra)
+ return -ENOMEM;
+
+ tegra->clk = devm_clk_get(&pdev->dev, "emc");
+ if (IS_ERR(tegra->clk)) {
+ err = PTR_ERR(tegra->clk);
+ dev_err(&pdev->dev, "failed to get emc clock: %d\n", err);
+ return err;
+ }
+
+ tegra->regs = mc->regs;
+
+ max_rate = clk_round_rate(tegra->clk, ULONG_MAX);
+
+ for (rate = 0; rate <= max_rate; rate++) {
+ rate = clk_round_rate(tegra->clk, rate);
+ dev_pm_opp_add(&pdev->dev, rate, 0);
+ }
+
+ 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))
+ return PTR_ERR(tegra->devfreq);
+
+ return 0;
+}
+
+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_devfeq_driver = {
+ .probe = tegra_devfeq_probe,
+ .remove = tegra_devfreq_remove,
+ .driver = {
+ .name = "tegra20-devfreq",
+ },
+};
+module_platform_driver(tegra_devfeq_driver);
+
+MODULE_ALIAS("platform:tegra20-devfreq");
+MODULE_AUTHOR("Dmitry Osipenko <digetx@...il.com>");
+MODULE_DESCRIPTION("NVIDIA Tegra20 devfreq driver");
+MODULE_LICENSE("GPL v2");
--
2.21.0
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