| /* |
| * CPU frequency scaling for OMAP using OPP information |
| * |
| * Copyright (C) 2005 Nokia Corporation |
| * Written by Tony Lindgren <tony@atomide.com> |
| * |
| * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King |
| * |
| * Copyright (C) 2007-2011 Texas Instruments, Inc. |
| * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar |
| * |
| * 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/types.h> |
| #include <linux/kernel.h> |
| #include <linux/sched.h> |
| #include <linux/cpufreq.h> |
| #include <linux/delay.h> |
| #include <linux/init.h> |
| #include <linux/err.h> |
| #include <linux/clk.h> |
| #include <linux/io.h> |
| #include <linux/opp.h> |
| #include <linux/cpu.h> |
| #include <linux/module.h> |
| #include <linux/regulator/consumer.h> |
| |
| #include <asm/smp_plat.h> |
| #include <asm/cpu.h> |
| |
| /* OPP tolerance in percentage */ |
| #define OPP_TOLERANCE 4 |
| |
| static struct cpufreq_frequency_table *freq_table; |
| static atomic_t freq_table_users = ATOMIC_INIT(0); |
| static struct clk *mpu_clk; |
| static struct device *mpu_dev; |
| static struct regulator *mpu_reg; |
| |
| static int omap_verify_speed(struct cpufreq_policy *policy) |
| { |
| if (!freq_table) |
| return -EINVAL; |
| return cpufreq_frequency_table_verify(policy, freq_table); |
| } |
| |
| static unsigned int omap_getspeed(unsigned int cpu) |
| { |
| unsigned long rate; |
| |
| if (cpu >= NR_CPUS) |
| return 0; |
| |
| rate = clk_get_rate(mpu_clk) / 1000; |
| return rate; |
| } |
| |
| static int omap_target(struct cpufreq_policy *policy, |
| unsigned int target_freq, |
| unsigned int relation) |
| { |
| unsigned int i; |
| int r, ret = 0; |
| struct cpufreq_freqs freqs; |
| struct opp *opp; |
| unsigned long freq, volt = 0, volt_old = 0, tol = 0; |
| |
| if (!freq_table) { |
| dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__, |
| policy->cpu); |
| return -EINVAL; |
| } |
| |
| ret = cpufreq_frequency_table_target(policy, freq_table, target_freq, |
| relation, &i); |
| if (ret) { |
| dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n", |
| __func__, policy->cpu, target_freq, ret); |
| return ret; |
| } |
| freqs.new = freq_table[i].frequency; |
| if (!freqs.new) { |
| dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__, |
| policy->cpu, target_freq); |
| return -EINVAL; |
| } |
| |
| freqs.old = omap_getspeed(policy->cpu); |
| |
| if (freqs.old == freqs.new && policy->cur == freqs.new) |
| return ret; |
| |
| /* notifiers */ |
| cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
| |
| freq = freqs.new * 1000; |
| ret = clk_round_rate(mpu_clk, freq); |
| if (IS_ERR_VALUE(ret)) { |
| dev_warn(mpu_dev, |
| "CPUfreq: Cannot find matching frequency for %lu\n", |
| freq); |
| return ret; |
| } |
| freq = ret; |
| |
| if (mpu_reg) { |
| rcu_read_lock(); |
| opp = opp_find_freq_ceil(mpu_dev, &freq); |
| if (IS_ERR(opp)) { |
| rcu_read_unlock(); |
| dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n", |
| __func__, freqs.new); |
| return -EINVAL; |
| } |
| volt = opp_get_voltage(opp); |
| rcu_read_unlock(); |
| tol = volt * OPP_TOLERANCE / 100; |
| volt_old = regulator_get_voltage(mpu_reg); |
| } |
| |
| dev_dbg(mpu_dev, "cpufreq-omap: %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 (mpu_reg && (freqs.new > freqs.old)) { |
| r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol); |
| if (r < 0) { |
| dev_warn(mpu_dev, "%s: unable to scale voltage up.\n", |
| __func__); |
| freqs.new = freqs.old; |
| goto done; |
| } |
| } |
| |
| ret = clk_set_rate(mpu_clk, freqs.new * 1000); |
| |
| /* scaling down? scale voltage after frequency */ |
| if (mpu_reg && (freqs.new < freqs.old)) { |
| r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol); |
| if (r < 0) { |
| dev_warn(mpu_dev, "%s: unable to scale voltage down.\n", |
| __func__); |
| ret = clk_set_rate(mpu_clk, freqs.old * 1000); |
| freqs.new = freqs.old; |
| goto done; |
| } |
| } |
| |
| freqs.new = omap_getspeed(policy->cpu); |
| |
| done: |
| /* notifiers */ |
| cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
| |
| return ret; |
| } |
| |
| static inline void freq_table_free(void) |
| { |
| if (atomic_dec_and_test(&freq_table_users)) |
| opp_free_cpufreq_table(mpu_dev, &freq_table); |
| } |
| |
| static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy) |
| { |
| int result = 0; |
| |
| mpu_clk = clk_get(NULL, "cpufreq_ck"); |
| if (IS_ERR(mpu_clk)) |
| return PTR_ERR(mpu_clk); |
| |
| if (policy->cpu >= NR_CPUS) { |
| result = -EINVAL; |
| goto fail_ck; |
| } |
| |
| policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu); |
| |
| if (!freq_table) |
| result = opp_init_cpufreq_table(mpu_dev, &freq_table); |
| |
| if (result) { |
| dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n", |
| __func__, policy->cpu, result); |
| goto fail_ck; |
| } |
| |
| atomic_inc_return(&freq_table_users); |
| |
| result = cpufreq_frequency_table_cpuinfo(policy, freq_table); |
| if (result) |
| goto fail_table; |
| |
| cpufreq_frequency_table_get_attr(freq_table, policy->cpu); |
| |
| policy->min = policy->cpuinfo.min_freq; |
| policy->max = policy->cpuinfo.max_freq; |
| policy->cur = omap_getspeed(policy->cpu); |
| |
| /* |
| * On OMAP SMP configuartion, both processors share the voltage |
| * and clock. So both CPUs needs to be scaled together and hence |
| * needs software co-ordination. Use cpufreq affected_cpus |
| * interface to handle this scenario. Additional is_smp() check |
| * is to keep SMP_ON_UP build working. |
| */ |
| if (is_smp()) |
| cpumask_setall(policy->cpus); |
| |
| /* FIXME: what's the actual transition time? */ |
| policy->cpuinfo.transition_latency = 300 * 1000; |
| |
| return 0; |
| |
| fail_table: |
| freq_table_free(); |
| fail_ck: |
| clk_put(mpu_clk); |
| return result; |
| } |
| |
| static int omap_cpu_exit(struct cpufreq_policy *policy) |
| { |
| freq_table_free(); |
| clk_put(mpu_clk); |
| return 0; |
| } |
| |
| static struct freq_attr *omap_cpufreq_attr[] = { |
| &cpufreq_freq_attr_scaling_available_freqs, |
| NULL, |
| }; |
| |
| static struct cpufreq_driver omap_driver = { |
| .flags = CPUFREQ_STICKY, |
| .verify = omap_verify_speed, |
| .target = omap_target, |
| .get = omap_getspeed, |
| .init = omap_cpu_init, |
| .exit = omap_cpu_exit, |
| .name = "omap", |
| .attr = omap_cpufreq_attr, |
| }; |
| |
| static int __init omap_cpufreq_init(void) |
| { |
| mpu_dev = get_cpu_device(0); |
| if (!mpu_dev) { |
| pr_warning("%s: unable to get the mpu device\n", __func__); |
| return -EINVAL; |
| } |
| |
| mpu_reg = regulator_get(mpu_dev, "vcc"); |
| if (IS_ERR(mpu_reg)) { |
| pr_warning("%s: unable to get MPU regulator\n", __func__); |
| mpu_reg = NULL; |
| } else { |
| /* |
| * Ensure physical regulator is present. |
| * (e.g. could be dummy regulator.) |
| */ |
| if (regulator_get_voltage(mpu_reg) < 0) { |
| pr_warn("%s: physical regulator not present for MPU\n", |
| __func__); |
| regulator_put(mpu_reg); |
| mpu_reg = NULL; |
| } |
| } |
| |
| return cpufreq_register_driver(&omap_driver); |
| } |
| |
| static void __exit omap_cpufreq_exit(void) |
| { |
| cpufreq_unregister_driver(&omap_driver); |
| } |
| |
| MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs"); |
| MODULE_LICENSE("GPL"); |
| module_init(omap_cpufreq_init); |
| module_exit(omap_cpufreq_exit); |