On 17-05-19, 17:35, 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. > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulie...@suse.de> > --- > drivers/cpufreq/Kconfig.arm | 8 +++ > drivers/cpufreq/Makefile | 1 + > drivers/cpufreq/raspberrypi-cpufreq.c | 79 +++++++++++++++++++++++++++ > 3 files changed, 88 insertions(+) > create mode 100644 drivers/cpufreq/raspberrypi-cpufreq.c > > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm > index 179a1d302f48..70e5f13f7632 100644 > --- a/drivers/cpufreq/Kconfig.arm > +++ b/drivers/cpufreq/Kconfig.arm > @@ -308,3 +308,11 @@ config ARM_PXA2xx_CPUFREQ > This add the CPUFreq driver support for Intel PXA2xx SOCs. > > If in doubt, say N. > + > +config ARM_RASPBERRYPI_CPUFREQ > + tristate "Raspberry Pi cpufreq support" > + depends on RASPBERRYPI_FIRMWARE || (RASPBERRYPI_FIRMWARE=n && > COMPILE_TEST)
What about: depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST > + help > + This adds the CPUFreq driver for Raspberry Pi > + > + If in doubt, say N. > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile > index 689b26c6f949..02678e9b2ff5 100644 > --- a/drivers/cpufreq/Makefile > +++ b/drivers/cpufreq/Makefile > @@ -84,6 +84,7 @@ obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o > obj-$(CONFIG_ARM_TEGRA186_CPUFREQ) += tegra186-cpufreq.o > obj-$(CONFIG_ARM_TI_CPUFREQ) += ti-cpufreq.o > obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o > +obj-$(CONFIG_ARM_RASPBERRYPI_CPUFREQ) += raspberrypi-cpufreq.o > > > > ################################################################################## > diff --git a/drivers/cpufreq/raspberrypi-cpufreq.c > b/drivers/cpufreq/raspberrypi-cpufreq.c > new file mode 100644 > index 000000000000..53cb3e5a8457 > --- /dev/null > +++ b/drivers/cpufreq/raspberrypi-cpufreq.c > @@ -0,0 +1,79 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Raspberry Pi cpufreq driver > + * > + * Copyright (C) 2019, Nicolas Saenz Julienne <nsaenzjulie...@suse.de> > + */ > + > +#include <linux/of.h> > +#include <linux/clk.h> > +#include <linux/cpu.h> > +#include <linux/module.h> > +#include <linux/pm_opp.h> > +#include <linux/cpufreq.h> > +#include <linux/platform_device.h> > + > +static const struct of_device_id machines[] __initconst = { > + { .compatible = "raspberrypi,3-model-b-plus" }, > + { .compatible = "raspberrypi,3-model-b" }, > + { /* sentinel */ } > +}; > + > +static int __init raspberrypi_cpufreq_driver_init(void) > +{ > + struct platform_device *pdev; > + struct cpumask shared_cpus; > + struct device *cpu_dev; > + struct clk *clk; > + long min, max; > + long rate; > + int ret; > + > + if (!of_match_node(machines, of_root)) > + return -ENODEV; > + > + 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, 0); > + if (IS_ERR(clk)) { > + dev_err(cpu_dev, "Cannot get clock for CPU0\n"); > + return PTR_ERR(clk); > + } You want to do a clk_put() somewhere ? > + > + /* > + * The max and min frequencies are configurable in the Raspberry Pi > + * firmware, so we query them at runtime > + */ > + min = clk_round_rate(clk, 0); > + max = clk_round_rate(clk, ULONG_MAX); > + > + for (rate = min; rate < max; rate += 100000000) { > + ret = dev_pm_opp_add(cpu_dev, rate, 0); > + if (ret) > + return ret; > + } > + > + ret = dev_pm_opp_add(cpu_dev, max, 0); > + if (ret) > + return ret; On errors, you should remove all previously added OPPs. > + > + cpumask_setall(&shared_cpus); > + dev_pm_opp_set_sharing_cpus(cpu_dev, &shared_cpus); Why are these required? This must be done by the cpufreq-dt driver anyway ? > + > + pdev = platform_device_register_data(NULL, "cpufreq-dt", -1, NULL, 0); > + ret = PTR_ERR_OR_ZERO(pdev); > + if (ret) > + dev_err(cpu_dev, "Failed to create platform device, %d\n", ret); > + > + return ret; > +} > + > +late_initcall(raspberrypi_cpufreq_driver_init); > + > +MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulie...@suse.de"); > +MODULE_DESCRIPTION("Raspberry Pi cpufreq driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.21.0 -- viresh