272 lines
7.1 KiB
C
272 lines
7.1 KiB
C
/*
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* ARM big.LITTLE Platforms CPUFreq support
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*
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* Copyright (C) 2013 ARM Ltd.
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* Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
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*
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* Copyright (C) 2013 Linaro.
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* Viresh Kumar <viresh.kumar@linaro.org>
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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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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/cpumask.h>
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#include <linux/export.h>
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#include <linux/of_platform.h>
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#include <linux/opp.h>
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#include <linux/slab.h>
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#include <linux/topology.h>
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#include <linux/types.h>
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#include "arm_big_little.h"
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/* Currently we support only two clusters */
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#define MAX_CLUSTERS 2
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static struct cpufreq_arm_bL_ops *arm_bL_ops;
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static struct clk *clk[MAX_CLUSTERS];
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static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS];
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static atomic_t cluster_usage[MAX_CLUSTERS] = {ATOMIC_INIT(0), ATOMIC_INIT(0)};
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static unsigned int bL_cpufreq_get(unsigned int cpu)
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{
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u32 cur_cluster = cpu_to_cluster(cpu);
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return clk_get_rate(clk[cur_cluster]) / 1000;
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}
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/* Validate policy frequency range */
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static int bL_cpufreq_verify_policy(struct cpufreq_policy *policy)
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{
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u32 cur_cluster = cpu_to_cluster(policy->cpu);
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return cpufreq_frequency_table_verify(policy, freq_table[cur_cluster]);
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}
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/* Set clock frequency */
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static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
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unsigned int target_freq, unsigned int relation)
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{
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struct cpufreq_freqs freqs;
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u32 cpu = policy->cpu, freq_tab_idx, cur_cluster;
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int ret = 0;
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cur_cluster = cpu_to_cluster(policy->cpu);
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freqs.old = bL_cpufreq_get(policy->cpu);
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/* Determine valid target frequency using freq_table */
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cpufreq_frequency_table_target(policy, freq_table[cur_cluster],
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target_freq, relation, &freq_tab_idx);
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freqs.new = freq_table[cur_cluster][freq_tab_idx].frequency;
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pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
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__func__, cpu, cur_cluster, freqs.old, target_freq,
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freqs.new);
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if (freqs.old == freqs.new)
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return 0;
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
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ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
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if (ret) {
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pr_err("clk_set_rate failed: %d\n", ret);
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freqs.new = freqs.old;
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}
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
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return ret;
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}
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static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
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{
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u32 cluster = cpu_to_cluster(cpu_dev->id);
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if (!atomic_dec_return(&cluster_usage[cluster])) {
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clk_put(clk[cluster]);
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opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
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dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
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}
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}
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static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
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{
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u32 cluster = cpu_to_cluster(cpu_dev->id);
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char name[14] = "cpu-cluster.";
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int ret;
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if (atomic_inc_return(&cluster_usage[cluster]) != 1)
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return 0;
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ret = arm_bL_ops->init_opp_table(cpu_dev);
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if (ret) {
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dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
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__func__, cpu_dev->id, ret);
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goto atomic_dec;
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}
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ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
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if (ret) {
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dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
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__func__, cpu_dev->id, ret);
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goto atomic_dec;
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}
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name[12] = cluster + '0';
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clk[cluster] = clk_get_sys(name, NULL);
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if (!IS_ERR(clk[cluster])) {
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dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
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__func__, clk[cluster], freq_table[cluster],
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cluster);
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return 0;
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}
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dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
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__func__, cpu_dev->id, cluster);
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ret = PTR_ERR(clk[cluster]);
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opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
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atomic_dec:
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atomic_dec(&cluster_usage[cluster]);
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dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
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cluster);
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return ret;
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}
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/* Per-CPU initialization */
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static int bL_cpufreq_init(struct cpufreq_policy *policy)
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{
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u32 cur_cluster = cpu_to_cluster(policy->cpu);
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struct device *cpu_dev;
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int ret;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("%s: failed to get cpu%d device\n", __func__,
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policy->cpu);
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return -ENODEV;
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}
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ret = get_cluster_clk_and_freq_table(cpu_dev);
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if (ret)
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return ret;
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ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
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if (ret) {
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dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
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policy->cpu, cur_cluster);
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put_cluster_clk_and_freq_table(cpu_dev);
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return ret;
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}
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cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
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if (arm_bL_ops->get_transition_latency)
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policy->cpuinfo.transition_latency =
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arm_bL_ops->get_transition_latency(cpu_dev);
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else
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policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
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policy->cur = bL_cpufreq_get(policy->cpu);
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cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
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dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
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return 0;
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}
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static int bL_cpufreq_exit(struct cpufreq_policy *policy)
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{
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struct device *cpu_dev;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("%s: failed to get cpu%d device\n", __func__,
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policy->cpu);
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return -ENODEV;
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}
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put_cluster_clk_and_freq_table(cpu_dev);
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dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
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return 0;
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}
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/* Export freq_table to sysfs */
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static struct freq_attr *bL_cpufreq_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static struct cpufreq_driver bL_cpufreq_driver = {
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.name = "arm-big-little",
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.flags = CPUFREQ_STICKY,
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.verify = bL_cpufreq_verify_policy,
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.target = bL_cpufreq_set_target,
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.get = bL_cpufreq_get,
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.init = bL_cpufreq_init,
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.exit = bL_cpufreq_exit,
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.have_governor_per_policy = true,
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.attr = bL_cpufreq_attr,
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};
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int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
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{
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int ret;
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if (arm_bL_ops) {
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pr_debug("%s: Already registered: %s, exiting\n", __func__,
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arm_bL_ops->name);
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return -EBUSY;
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}
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if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
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pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
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return -ENODEV;
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}
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arm_bL_ops = ops;
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ret = cpufreq_register_driver(&bL_cpufreq_driver);
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if (ret) {
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pr_info("%s: Failed registering platform driver: %s, err: %d\n",
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__func__, ops->name, ret);
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arm_bL_ops = NULL;
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} else {
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pr_info("%s: Registered platform driver: %s\n", __func__,
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ops->name);
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(bL_cpufreq_register);
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void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
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{
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if (arm_bL_ops != ops) {
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pr_err("%s: Registered with: %s, can't unregister, exiting\n",
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__func__, arm_bL_ops->name);
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return;
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}
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cpufreq_unregister_driver(&bL_cpufreq_driver);
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pr_info("%s: Un-registered platform driver: %s\n", __func__,
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arm_bL_ops->name);
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arm_bL_ops = NULL;
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}
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EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);
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