diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0759-cpufreq-add-driver-for-Raspberry-Pi.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0759-cpufreq-add-driver-for-Raspberry-Pi.patch | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0759-cpufreq-add-driver-for-Raspberry-Pi.patch b/target/linux/brcm2708/patches-4.19/950-0759-cpufreq-add-driver-for-Raspberry-Pi.patch new file mode 100644 index 0000000000..7785caf129 --- /dev/null +++ b/target/linux/brcm2708/patches-4.19/950-0759-cpufreq-add-driver-for-Raspberry-Pi.patch @@ -0,0 +1,161 @@ +From 1c0d3626312369837bc18051ed6c9611323fce87 Mon Sep 17 00:00:00 2001 +From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> +Date: Wed, 12 Jun 2019 20:24:56 +0200 +Subject: [PATCH] cpufreq: add driver for Raspberry Pi + +Commit d3df18a97e586702920337056540267807b23f8e upstream. + +Raspberry Pi's firmware offers and interface though which update it's +performance requirements. It allows us to request for specific runtime +frequencies, which the firmware might or might not respect, depending on +the firmware configuration and thermals. + +As the maximum and minimum frequencies are configurable in the firmware +there is no way to know in advance their values. So the Raspberry Pi +cpufreq driver queries them, builds an opp frequency table to then +launch cpufreq-dt. + +Also, as the firmware interface might be configured as a module, making +the cpu clock unavailable during init, this implements a full fledged +driver, as opposed to most drivers registering cpufreq-dt, which only +make use of an init routine. + +Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> +Acked-by: Eric Anholt <eric@anholt.net> +Reviewed-by: Stephen Boyd <sboyd@kernel.org> +Acked-by: Stefan Wahren <stefan.wahren@i2se.com> +Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> +--- + drivers/cpufreq/Kconfig.arm | 8 +++ + drivers/cpufreq/Makefile | 1 + + drivers/cpufreq/raspberrypi-cpufreq.c | 97 +++++++++++++++++++++++++++ + 3 files changed, 106 insertions(+) + create mode 100644 drivers/cpufreq/raspberrypi-cpufreq.c + +--- a/drivers/cpufreq/Kconfig.arm ++++ b/drivers/cpufreq/Kconfig.arm +@@ -121,6 +121,14 @@ config ARM_QCOM_CPUFREQ_KRYO + + If in doubt, say N. + ++config ARM_RASPBERRYPI_CPUFREQ ++ tristate "Raspberry Pi cpufreq support" ++ depends on CLK_RASPBERRYPI || COMPILE_TEST ++ help ++ This adds the CPUFreq driver for Raspberry Pi ++ ++ If in doubt, say N. ++ + config ARM_S3C_CPUFREQ + bool + help +--- a/drivers/cpufreq/Makefile ++++ b/drivers/cpufreq/Makefile +@@ -65,6 +65,7 @@ obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += o + obj-$(CONFIG_ARM_PXA2xx_CPUFREQ) += pxa2xx-cpufreq.o + obj-$(CONFIG_PXA3xx) += pxa3xx-cpufreq.o + obj-$(CONFIG_ARM_QCOM_CPUFREQ_KRYO) += qcom-cpufreq-kryo.o ++obj-$(CONFIG_ARM_RASPBERRYPI_CPUFREQ) += raspberrypi-cpufreq.o + obj-$(CONFIG_ARM_S3C2410_CPUFREQ) += s3c2410-cpufreq.o + obj-$(CONFIG_ARM_S3C2412_CPUFREQ) += s3c2412-cpufreq.o + obj-$(CONFIG_ARM_S3C2416_CPUFREQ) += s3c2416-cpufreq.o +--- /dev/null ++++ b/drivers/cpufreq/raspberrypi-cpufreq.c +@@ -0,0 +1,97 @@ ++// SPDX-License-Identifier: GPL-2.0 ++/* ++ * Raspberry Pi cpufreq driver ++ * ++ * Copyright (C) 2019, Nicolas Saenz Julienne <nsaenzjulienne@suse.de> ++ */ ++ ++#include <linux/clk.h> ++#include <linux/cpu.h> ++#include <linux/cpufreq.h> ++#include <linux/module.h> ++#include <linux/platform_device.h> ++#include <linux/pm_opp.h> ++ ++#define RASPBERRYPI_FREQ_INTERVAL 100000000 ++ ++static struct platform_device *cpufreq_dt; ++ ++static int raspberrypi_cpufreq_probe(struct platform_device *pdev) ++{ ++ struct device *cpu_dev; ++ unsigned long min, max; ++ unsigned long rate; ++ struct clk *clk; ++ int ret; ++ ++ cpu_dev = get_cpu_device(0); ++ if (!cpu_dev) { ++ pr_err("Cannot get CPU for cpufreq driver\n"); ++ return -ENODEV; ++ } ++ ++ clk = clk_get(cpu_dev, NULL); ++ if (IS_ERR(clk)) { ++ dev_err(cpu_dev, "Cannot get clock for CPU0\n"); ++ return PTR_ERR(clk); ++ } ++ ++ /* ++ * The max and min frequencies are configurable in the Raspberry Pi ++ * firmware, so we query them at runtime. ++ */ ++ min = roundup(clk_round_rate(clk, 0), RASPBERRYPI_FREQ_INTERVAL); ++ max = roundup(clk_round_rate(clk, ULONG_MAX), RASPBERRYPI_FREQ_INTERVAL); ++ clk_put(clk); ++ ++ for (rate = min; rate <= max; rate += RASPBERRYPI_FREQ_INTERVAL) { ++ ret = dev_pm_opp_add(cpu_dev, rate, 0); ++ if (ret) ++ goto remove_opp; ++ } ++ ++ cpufreq_dt = platform_device_register_simple("cpufreq-dt", -1, NULL, 0); ++ ret = PTR_ERR_OR_ZERO(cpufreq_dt); ++ if (ret) { ++ dev_err(cpu_dev, "Failed to create platform device, %d\n", ret); ++ goto remove_opp; ++ } ++ ++ return 0; ++ ++remove_opp: ++ dev_pm_opp_remove_all_dynamic(cpu_dev); ++ ++ return ret; ++} ++ ++static int raspberrypi_cpufreq_remove(struct platform_device *pdev) ++{ ++ struct device *cpu_dev; ++ ++ cpu_dev = get_cpu_device(0); ++ if (cpu_dev) ++ dev_pm_opp_remove_all_dynamic(cpu_dev); ++ ++ platform_device_unregister(cpufreq_dt); ++ ++ return 0; ++} ++ ++/* ++ * Since the driver depends on clk-raspberrypi, which may return EPROBE_DEFER, ++ * all the activity is performed in the probe, which may be defered as well. ++ */ ++static struct platform_driver raspberrypi_cpufreq_driver = { ++ .driver = { ++ .name = "raspberrypi-cpufreq", ++ }, ++ .probe = raspberrypi_cpufreq_probe, ++ .remove = raspberrypi_cpufreq_remove, ++}; ++module_platform_driver(raspberrypi_cpufreq_driver); ++ ++MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de"); ++MODULE_DESCRIPTION("Raspberry Pi cpufreq driver"); ++MODULE_LICENSE("GPL"); ++MODULE_ALIAS("platform:raspberrypi-cpufreq"); |