| Message ID | 20190611175839.28351-5-nsaenzjulienne@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cpufreq support for Raspberry Pi | expand |
On Tue, 2019-06-11 at 19:58 +0200, Nicolas Saenz Julienne wrote: > 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> > --- Changes since v2: - Round OPP rates > Changes since v1: > - Remove compatible checks > - Add module support, now full fledged driver > - Use NULL in clk_get() > > 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 > > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm > index 6f65b7f05496..56c31a78c692 100644 > --- a/drivers/cpufreq/Kconfig.arm > +++ b/drivers/cpufreq/Kconfig.arm > @@ -142,6 +142,14 @@ config ARM_QCOM_CPUFREQ_HW > The driver implements the cpufreq interface for this HW engine. > Say Y if you want to support CPUFreq HW. > > +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 > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile > index 7bcda2273d0c..5a6c70d26c98 100644 > --- a/drivers/cpufreq/Makefile > +++ b/drivers/cpufreq/Makefile > @@ -65,6 +65,7 @@ obj-$(CONFIG_ARM_PXA2xx_CPUFREQ) += pxa2xx-cpufreq.o > obj-$(CONFIG_PXA3xx) += pxa3xx-cpufreq.o > obj-$(CONFIG_ARM_QCOM_CPUFREQ_HW) += qcom-cpufreq-hw.o > obj-$(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 > diff --git a/drivers/cpufreq/raspberrypi-cpufreq.c > b/drivers/cpufreq/raspberrypi-cpufreq.c > new file mode 100644 > index 000000000000..2bc7d9734272 > --- /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");
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 6f65b7f05496..56c31a78c692 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -142,6 +142,14 @@ config ARM_QCOM_CPUFREQ_HW The driver implements the cpufreq interface for this HW engine. Say Y if you want to support CPUFreq HW. +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 diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 7bcda2273d0c..5a6c70d26c98 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -65,6 +65,7 @@ obj-$(CONFIG_ARM_PXA2xx_CPUFREQ) += pxa2xx-cpufreq.o obj-$(CONFIG_PXA3xx) += pxa3xx-cpufreq.o obj-$(CONFIG_ARM_QCOM_CPUFREQ_HW) += qcom-cpufreq-hw.o obj-$(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 diff --git a/drivers/cpufreq/raspberrypi-cpufreq.c b/drivers/cpufreq/raspberrypi-cpufreq.c new file mode 100644 index 000000000000..2bc7d9734272 --- /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");