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200 lines
4.8 KiB
200 lines
4.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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 <[email protected]> |
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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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#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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clk_put(policy->clk); |
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return result; |
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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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cpufreq_generic_init(policy, freq_table, 300 * 1000); |
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dev_pm_opp_of_register_em(mpu_dev, policy->cpus); |
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return 0; |
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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_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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