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![Viresh Kumar](/assets/img/avatar_default.png)
This patch updates dev_pm_opp_find_freq_*() routines to get a reference to the OPPs returned by them. Also updates the users of dev_pm_opp_find_freq_*() routines to call dev_pm_opp_put() after they are done using the OPPs. As it is guaranteed the that OPPs wouldn't get freed while being used, the RCU read side locking present with the users isn't required anymore. Drop it as well. This patch also updates all users of devfreq_recommended_opp() which was returning an OPP received from the OPP core. Note that some of the OPP core routines have gained rcu_read_{lock|unlock}() calls, as those still use RCU specific APIs within them. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> [Devfreq] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
206 lines
5 KiB
C
206 lines
5 KiB
C
/*
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* CPU frequency scaling for OMAP using OPP information
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*
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* Copyright (C) 2005 Nokia Corporation
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* Written by Tony Lindgren <tony@atomide.com>
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*
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* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
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*
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* Copyright (C) 2007-2011 Texas Instruments, Inc.
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* - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/cpufreq.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/pm_opp.h>
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/consumer.h>
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#include <asm/smp_plat.h>
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#include <asm/cpu.h>
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/* OPP tolerance in percentage */
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#define OPP_TOLERANCE 4
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static struct cpufreq_frequency_table *freq_table;
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static atomic_t freq_table_users = ATOMIC_INIT(0);
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static struct device *mpu_dev;
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static struct regulator *mpu_reg;
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static int omap_target(struct cpufreq_policy *policy, unsigned int index)
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{
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int r, ret;
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struct dev_pm_opp *opp;
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unsigned long freq, volt = 0, volt_old = 0, tol = 0;
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unsigned int old_freq, new_freq;
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old_freq = policy->cur;
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new_freq = freq_table[index].frequency;
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freq = new_freq * 1000;
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ret = clk_round_rate(policy->clk, freq);
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if (ret < 0) {
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dev_warn(mpu_dev,
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"CPUfreq: Cannot find matching frequency for %lu\n",
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freq);
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return ret;
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}
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freq = ret;
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if (mpu_reg) {
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opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
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if (IS_ERR(opp)) {
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dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
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__func__, new_freq);
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return -EINVAL;
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}
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volt = dev_pm_opp_get_voltage(opp);
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dev_pm_opp_put(opp);
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tol = volt * OPP_TOLERANCE / 100;
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volt_old = regulator_get_voltage(mpu_reg);
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}
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dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
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old_freq / 1000, volt_old ? volt_old / 1000 : -1,
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new_freq / 1000, volt ? volt / 1000 : -1);
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/* scaling up? scale voltage before frequency */
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if (mpu_reg && (new_freq > old_freq)) {
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r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
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if (r < 0) {
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dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
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__func__);
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return r;
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}
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}
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ret = clk_set_rate(policy->clk, new_freq * 1000);
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/* scaling down? scale voltage after frequency */
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if (mpu_reg && (new_freq < old_freq)) {
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r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
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if (r < 0) {
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dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
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__func__);
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clk_set_rate(policy->clk, old_freq * 1000);
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return r;
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}
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}
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return ret;
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}
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static inline void freq_table_free(void)
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{
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if (atomic_dec_and_test(&freq_table_users))
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dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
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}
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static int omap_cpu_init(struct cpufreq_policy *policy)
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{
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int result;
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policy->clk = clk_get(NULL, "cpufreq_ck");
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if (IS_ERR(policy->clk))
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return PTR_ERR(policy->clk);
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if (!freq_table) {
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result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
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if (result) {
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dev_err(mpu_dev,
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"%s: cpu%d: failed creating freq table[%d]\n",
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__func__, policy->cpu, result);
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goto fail;
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}
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}
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atomic_inc_return(&freq_table_users);
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/* FIXME: what's the actual transition time? */
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result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
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if (!result)
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return 0;
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freq_table_free();
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fail:
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clk_put(policy->clk);
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return result;
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}
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static int omap_cpu_exit(struct cpufreq_policy *policy)
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{
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freq_table_free();
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clk_put(policy->clk);
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return 0;
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}
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static struct cpufreq_driver omap_driver = {
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.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = omap_target,
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.get = cpufreq_generic_get,
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.init = omap_cpu_init,
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.exit = omap_cpu_exit,
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.name = "omap",
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.attr = cpufreq_generic_attr,
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};
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static int omap_cpufreq_probe(struct platform_device *pdev)
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{
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mpu_dev = get_cpu_device(0);
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if (!mpu_dev) {
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pr_warn("%s: unable to get the MPU device\n", __func__);
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return -EINVAL;
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}
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mpu_reg = regulator_get(mpu_dev, "vcc");
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if (IS_ERR(mpu_reg)) {
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pr_warn("%s: unable to get MPU regulator\n", __func__);
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mpu_reg = NULL;
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} else {
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/*
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* Ensure physical regulator is present.
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* (e.g. could be dummy regulator.)
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*/
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if (regulator_get_voltage(mpu_reg) < 0) {
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pr_warn("%s: physical regulator not present for MPU\n",
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__func__);
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regulator_put(mpu_reg);
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mpu_reg = NULL;
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}
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}
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return cpufreq_register_driver(&omap_driver);
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}
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static int omap_cpufreq_remove(struct platform_device *pdev)
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{
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return cpufreq_unregister_driver(&omap_driver);
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}
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static struct platform_driver omap_cpufreq_platdrv = {
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.driver = {
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.name = "omap-cpufreq",
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},
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.probe = omap_cpufreq_probe,
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.remove = omap_cpufreq_remove,
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};
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module_platform_driver(omap_cpufreq_platdrv);
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MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
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MODULE_LICENSE("GPL");
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