Krait processors have individual clocks for each CPU that can scale independently from one another. cpufreq-cpu0 is fairly close to this, but assumes that there is only one clock for all CPUs. Add a driver to support the Krait configuration.
TODO: Merge into cpufreq-cpu0? Or make generic? Signed-off-by: Stephen Boyd <[email protected]> --- drivers/cpufreq/Kconfig | 13 +++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/cpufreq-krait.c | 190 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 204 insertions(+) create mode 100644 drivers/cpufreq/cpufreq-krait.c diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index ffe350f86bca..e9826c85a777 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -196,6 +196,19 @@ config GENERIC_CPUFREQ_CPU0 If in doubt, say N. +config GENERIC_CPUFREQ_KRAIT + tristate "Krait cpufreq driver" + depends on HAVE_CLK && OF + # if CPU_THERMAL is on and THERMAL=m, CPU0 cannot be =y: + depends on !CPU_THERMAL || THERMAL + select PM_OPP + help + This adds a generic cpufreq driver for CPU0 frequency management. + It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) + systems which share clock and voltage across all CPUs. + + If in doubt, say N. + menu "x86 CPU frequency scaling drivers" depends on X86 source "drivers/cpufreq/Kconfig.x86" diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 738c8b7b17dc..f5c9f68dcc0f 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -14,6 +14,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE) += cpufreq_conservative.o obj-$(CONFIG_CPU_FREQ_GOV_COMMON) += cpufreq_governor.o obj-$(CONFIG_GENERIC_CPUFREQ_CPU0) += cpufreq-cpu0.o +obj-$(CONFIG_CPUFREQ_KRAIT) += cpufreq-krait.o ################################################################################## # x86 drivers. diff --git a/drivers/cpufreq/cpufreq-krait.c b/drivers/cpufreq/cpufreq-krait.c new file mode 100644 index 000000000000..7b38b9c948e5 --- /dev/null +++ b/drivers/cpufreq/cpufreq-krait.c @@ -0,0 +1,190 @@ +/* + * Copyright (C) 2012 Freescale Semiconductor, Inc. + * Copyright (c) 2014, The Linux Foundation. All rights reserved. + * + * The OPP code in function krait_set_target() is reused from + * drivers/cpufreq/omap-cpufreq.c + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/clk.h> +#include <linux/cpu.h> +#include <linux/cpu_cooling.h> +#include <linux/cpufreq.h> +#include <linux/cpumask.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/pm_opp.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/thermal.h> + +static unsigned int transition_latency; + +static struct device *cpu_dev; +static DEFINE_PER_CPU(struct clk *, krait_cpu_clks); +static struct cpufreq_frequency_table *freq_table; +static struct thermal_cooling_device *cdev; + +static int krait_set_target(struct cpufreq_policy *policy, unsigned int index) +{ + unsigned long volt = 0, volt_old = 0; + unsigned int old_freq, new_freq; + long freq_Hz, freq_exact; + int ret; + struct clk *cpu_clk; + + cpu_clk = per_cpu(krait_cpu_clks, policy->cpu); + + freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000); + if (freq_Hz <= 0) + freq_Hz = freq_table[index].frequency * 1000; + + freq_exact = freq_Hz; + new_freq = freq_Hz / 1000; + old_freq = clk_get_rate(cpu_clk) / 1000; + + pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n", + old_freq / 1000, volt_old ? volt_old / 1000 : -1, + new_freq / 1000, volt ? volt / 1000 : -1); + + ret = clk_set_rate(cpu_clk, freq_exact); + if (ret) + pr_err("failed to set clock rate: %d\n", ret); + + return ret; +} + +static int krait_cpufreq_init(struct cpufreq_policy *policy) +{ + int ret; + + policy->clk = per_cpu(krait_cpu_clks, policy->cpu); + + ret = cpufreq_table_validate_and_show(policy, freq_table); + if (ret) { + pr_err("%s: invalid frequency table: %d\n", __func__, ret); + return ret; + } + + policy->cpuinfo.transition_latency = transition_latency; + + return 0; +} + +static struct cpufreq_driver krait_cpufreq_driver = { + .flags = CPUFREQ_STICKY, + .verify = cpufreq_generic_frequency_table_verify, + .target_index = krait_set_target, + .get = cpufreq_generic_get, + .init = krait_cpufreq_init, + .name = "generic_krait", + .attr = cpufreq_generic_attr, +}; + +static int krait_cpufreq_probe(struct platform_device *pdev) +{ + struct device_node *np; + int ret; + unsigned int cpu; + struct device *dev; + struct clk *clk; + + cpu_dev = get_cpu_device(0); + if (!cpu_dev) { + pr_err("failed to get krait device\n"); + return -ENODEV; + } + + np = of_node_get(cpu_dev->of_node); + if (!np) { + pr_err("failed to find krait node\n"); + return -ENOENT; + } + + for_each_possible_cpu(cpu) { + dev = get_cpu_device(cpu); + if (!dev) { + pr_err("failed to get krait device\n"); + ret = -ENOENT; + goto out_put_node; + } + per_cpu(krait_cpu_clks, cpu) = clk = devm_clk_get(dev, NULL); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + goto out_put_node; + } + } + + ret = of_init_opp_table(cpu_dev); + if (ret) { + pr_err("failed to init OPP table: %d\n", ret); + goto out_put_node; + } + + ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); + if (ret) { + pr_err("failed to init cpufreq table: %d\n", ret); + goto out_put_node; + } + + if (of_property_read_u32(np, "clock-latency", &transition_latency)) + transition_latency = CPUFREQ_ETERNAL; + + ret = cpufreq_register_driver(&krait_cpufreq_driver); + if (ret) { + pr_err("failed register driver: %d\n", ret); + goto out_free_table; + } + of_node_put(np); + + /* + * For now, just loading the cooling device; + * thermal DT code takes care of matching them. + */ + for_each_possible_cpu(cpu) { + dev = get_cpu_device(cpu); + np = of_node_get(dev->of_node); + if (of_find_property(np, "#cooling-cells", NULL)) { + cdev = of_cpufreq_cooling_register(np, cpumask_of(cpu)); + if (IS_ERR(cdev)) + pr_err("running cpufreq without cooling device: %ld\n", + PTR_ERR(cdev)); + } + of_node_put(np); + } + + return 0; + +out_free_table: + dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); +out_put_node: + of_node_put(np); + return ret; +} + +static int krait_cpufreq_remove(struct platform_device *pdev) +{ + cpufreq_cooling_unregister(cdev); + cpufreq_unregister_driver(&krait_cpufreq_driver); + dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); + + return 0; +} + +static struct platform_driver krait_cpufreq_platdrv = { + .driver = { + .name = "cpufreq-krait", + .owner = THIS_MODULE, + }, + .probe = krait_cpufreq_probe, + .remove = krait_cpufreq_remove, +}; +module_platform_driver(krait_cpufreq_platdrv); + +MODULE_DESCRIPTION("Krait CPUfreq driver"); +MODULE_LICENSE("GPL v2"); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
