/* * Copyright (C) 2012 Freescale Semiconductor, Inc. * * The OPP code in function cpu0_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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/clk.h> #include <linux/cpufreq.h> #include <linux/err.h> #include <linux/module.h> #include <linux/of.h> #include <linux/opp.h> #include <linux/platform_device.h> #include <linux/regulator/consumer.h> #include <linux/slab.h> static unsigned int transition_latency; static unsigned int voltage_tolerance; /* in percentage */ static struct device *cpu_dev; static struct clk *cpu_clk; static struct regulator *cpu_reg; static struct cpufreq_frequency_table *freq_table; static int cpu0_verify_speed(struct cpufreq_policy *policy) { return cpufreq_frequency_table_verify(policy, freq_table); } static unsigned int cpu0_get_speed(unsigned int cpu) { return clk_get_rate(cpu_clk) / 1000; } static int cpu0_set_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { struct cpufreq_freqs freqs; struct opp *opp; unsigned long freq_Hz, volt = 0, volt_old = 0, tol = 0; unsigned int index, cpu; int ret; ret = cpufreq_frequency_table_target(policy, freq_table, target_freq, relation, &index); if (ret) { pr_err("failed to match target freqency %d: %d\n", target_freq, ret); return ret; } freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000); if (freq_Hz < 0) freq_Hz = freq_table[index].frequency * 1000; freqs.new = freq_Hz / 1000; freqs.old = clk_get_rate(cpu_clk) / 1000; if (freqs.old == freqs.new) return 0; for_each_online_cpu(cpu) { freqs.cpu = cpu; cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); } if (cpu_reg) { rcu_read_lock(); opp = opp_find_freq_ceil(cpu_dev, &freq_Hz); if (IS_ERR(opp)) { rcu_read_unlock(); pr_err("failed to find OPP for %ld\n", freq_Hz); return PTR_ERR(opp); } volt = opp_get_voltage(opp); rcu_read_unlock(); tol = volt * voltage_tolerance / 100; volt_old = regulator_get_voltage(cpu_reg); } pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n", freqs.old / 1000, volt_old ? volt_old / 1000 : -1, freqs.new / 1000, volt ? volt / 1000 : -1); /* scaling up? scale voltage before frequency */ if (cpu_reg && freqs.new > freqs.old) { ret = regulator_set_voltage_tol(cpu_reg, volt, tol); if (ret) { pr_err("failed to scale voltage up: %d\n", ret); freqs.new = freqs.old; return ret; } } ret = clk_set_rate(cpu_clk, freqs.new * 1000); if (ret) { pr_err("failed to set clock rate: %d\n", ret); if (cpu_reg) regulator_set_voltage_tol(cpu_reg, volt_old, tol); return ret; } /* scaling down? scale voltage after frequency */ if (cpu_reg && freqs.new < freqs.old) { ret = regulator_set_voltage_tol(cpu_reg, volt, tol); if (ret) { pr_err("failed to scale voltage down: %d\n", ret); clk_set_rate(cpu_clk, freqs.old * 1000); freqs.new = freqs.old; return ret; } } for_each_online_cpu(cpu) { freqs.cpu = cpu; cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); } return 0; } static int cpu0_cpufreq_init(struct cpufreq_policy *policy) { int ret; if (policy->cpu != 0) return -EINVAL; ret = cpufreq_frequency_table_cpuinfo(policy, freq_table); if (ret) { pr_err("invalid frequency table: %d\n", ret); return ret; } policy->cpuinfo.transition_latency = transition_latency; policy->cur = clk_get_rate(cpu_clk) / 1000; /* * The driver only supports the SMP configuartion where all processors * share the clock and voltage and clock. Use cpufreq affected_cpus * interface to have all CPUs scaled together. */ cpumask_setall(policy->cpus); cpufreq_frequency_table_get_attr(freq_table, policy->cpu); return 0; } static int cpu0_cpufreq_exit(struct cpufreq_policy *policy) { cpufreq_frequency_table_put_attr(policy->cpu); return 0; } static struct freq_attr *cpu0_cpufreq_attr[] = { &cpufreq_freq_attr_scaling_available_freqs, NULL, }; static struct cpufreq_driver cpu0_cpufreq_driver = { .flags = CPUFREQ_STICKY, .verify = cpu0_verify_speed, .target = cpu0_set_target, .get = cpu0_get_speed, .init = cpu0_cpufreq_init, .exit = cpu0_cpufreq_exit, .name = "generic_cpu0", .attr = cpu0_cpufreq_attr, }; static int cpu0_cpufreq_probe(struct platform_device *pdev) { struct device_node *np; int ret; for_each_child_of_node(of_find_node_by_path("/cpus"), np) { if (of_get_property(np, "operating-points", NULL)) break; } if (!np) { pr_err("failed to find cpu0 node\n"); return -ENOENT; } cpu_dev = &pdev->dev; cpu_dev->of_node = np; cpu_clk = devm_clk_get(cpu_dev, NULL); if (IS_ERR(cpu_clk)) { ret = PTR_ERR(cpu_clk); pr_err("failed to get cpu0 clock: %d\n", ret); goto out_put_node; } cpu_reg = devm_regulator_get(cpu_dev, "cpu0"); if (IS_ERR(cpu_reg)) { pr_warn("failed to get cpu0 regulator\n"); cpu_reg = NULL; } ret = of_init_opp_table(cpu_dev); if (ret) { pr_err("failed to init OPP table: %d\n", ret); goto out_put_node; } ret = opp_init_cpufreq_table(cpu_dev, &freq_table); if (ret) { pr_err("failed to init cpufreq table: %d\n", ret); goto out_put_node; } of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance); if (of_property_read_u32(np, "clock-latency", &transition_latency)) transition_latency = CPUFREQ_ETERNAL; if (cpu_reg) { struct opp *opp; unsigned long min_uV, max_uV; int i; /* * OPP is maintained in order of increasing frequency, and * freq_table initialised from OPP is therefore sorted in the * same order. */ for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) ; rcu_read_lock(); opp = opp_find_freq_exact(cpu_dev, freq_table[0].frequency * 1000, true); min_uV = opp_get_voltage(opp); opp = opp_find_freq_exact(cpu_dev, freq_table[i-1].frequency * 1000, true); max_uV = opp_get_voltage(opp); rcu_read_unlock(); ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); if (ret > 0) transition_latency += ret * 1000; } ret = cpufreq_register_driver(&cpu0_cpufreq_driver); if (ret) { pr_err("failed register driver: %d\n", ret); goto out_free_table; } of_node_put(np); return 0; out_free_table: opp_free_cpufreq_table(cpu_dev, &freq_table); out_put_node: of_node_put(np); return ret; } static int cpu0_cpufreq_remove(struct platform_device *pdev) { cpufreq_unregister_driver(&cpu0_cpufreq_driver); opp_free_cpufreq_table(cpu_dev, &freq_table); return 0; } static struct platform_driver cpu0_cpufreq_platdrv = { .driver = { .name = "cpufreq-cpu0", .owner = THIS_MODULE, }, .probe = cpu0_cpufreq_probe, .remove = cpu0_cpufreq_remove, }; module_platform_driver(cpu0_cpufreq_platdrv); MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); MODULE_DESCRIPTION("Generic CPU0 cpufreq driver"); MODULE_LICENSE("GPL");