On Thu, May 02, 2019 at 02:38:15AM +0300, Dmitry Osipenko wrote: > 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. > > Reviewed-by: Chanwoo Choi > Signed-off-by: Dmitry Osipenko > --- > MAINTAINERS | 8 ++ > drivers/devfreq/Kconfig | 10 ++ > drivers/devfreq/Makefile | 1 + > drivers/devfreq/tegra20-devfreq.c | 212 ++++++++++++++++++++++++++++++ > 4 files changed, 231 insertions(+) > create mode 100644 drivers/devfreq/tegra20-devfreq.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 98edc38bfd7b..e7e434f74038 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -10098,6 +10098,14 @@ 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 > +L: linux-pm@vger.kernel.org > +L: linux-tegra@vger.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@kvack.org > W: http://www.linux-mm.org > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > index a6bba6e1e7d9..1530dbefa31f 100644 > --- a/drivers/devfreq/Kconfig > +++ b/drivers/devfreq/Kconfig > @@ -100,6 +100,16 @@ 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 "NVIDIA Tegra20 DEVFREQ Driver" > + depends on (TEGRA_MC && TEGRA20_EMC) || COMPILE_TEST > + select DEVFREQ_GOV_SIMPLE_ONDEMAND > + select PM_OPP Again, I'm not sure the COMPILE_TEST will work here unless you add a few more dependencies. Thierry > + 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 47e5aeeebfd1..338ae8440db6 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) += tegra30-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..ff82bac9ee4e > --- /dev/null > +++ b/drivers/devfreq/tegra20-devfreq.c > @@ -0,0 +1,212 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * NVIDIA Tegra20 devfreq driver > + * > + * Copyright (C) 2019 GRATE-DRIVER project > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > + > +#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)) { > + err = PTR_ERR(tegra->emc_clock); > + dev_err(&pdev->dev, "failed to get emc clock: %d\n", err); > + return err; > + } > + > + 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 "); > +MODULE_DESCRIPTION("NVIDIA Tegra20 devfreq driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.21.0 >