241 lines
5.8 KiB
C
241 lines
5.8 KiB
C
/*
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* Derived from drivers/cpuquiet/cpuquiet-tegra.c
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*
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* Copyright (c) 2012-2013 NVIDIA CORPORATION. All rights reserved.
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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 as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/cpu.h>
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#include <linux/cpuquiet.h>
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#include <linux/pm_qos.h>
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#include <linux/sched.h>
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#define DEFAULT_HOTPLUG_DELAY_MS 100
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static DEFINE_MUTEX(cpuquiet_cpu_lock);
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static struct workqueue_struct *cpuquiet_wq;
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static struct work_struct cpuquiet_work;
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static wait_queue_head_t wait_cpu;
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static unsigned long hotplug_timeout;
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static struct cpumask cr_online_requests;
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static struct cpumask cr_offline_requests;
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static void cpuquiet_work_func(struct work_struct *work);
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static int update_core_config(unsigned int cpunumber, bool up)
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{
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int ret = 0;
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mutex_lock(&cpuquiet_cpu_lock);
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if (up) {
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cpumask_set_cpu(cpunumber, &cr_online_requests);
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cpumask_clear_cpu(cpunumber, &cr_offline_requests);
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queue_work(cpuquiet_wq, &cpuquiet_work);
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} else {
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cpumask_set_cpu(cpunumber, &cr_offline_requests);
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cpumask_clear_cpu(cpunumber, &cr_online_requests);
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queue_work(cpuquiet_wq, &cpuquiet_work);
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}
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mutex_unlock(&cpuquiet_cpu_lock);
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return ret;
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}
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int cpuquiet_cpu_down(unsigned int cpunumber, bool sync)
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{
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unsigned long timeout = msecs_to_jiffies(hotplug_timeout);
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int err = 0;
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err = update_core_config(cpunumber, false);
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if (err || !sync)
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return err;
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err = wait_event_interruptible_timeout(wait_cpu, !cpu_online(cpunumber),
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timeout);
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if (err < 0)
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return err;
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if (err > 0)
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return 0;
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else
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return -ETIMEDOUT;
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}
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EXPORT_SYMBOL(cpuquiet_cpu_down);
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int cpuquiet_cpu_up(unsigned int cpunumber, bool sync)
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{
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unsigned long timeout = msecs_to_jiffies(hotplug_timeout);
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int err = 0;
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err = update_core_config(cpunumber, true);
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if (err || !sync)
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return err;
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err = wait_event_interruptible_timeout(wait_cpu, cpu_online(cpunumber),
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timeout);
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if (err < 0)
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return err;
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if (err > 0)
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return 0;
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else
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return -ETIMEDOUT;
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}
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EXPORT_SYMBOL(cpuquiet_cpu_up);
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static void __cpuinit cpuquiet_work_func(struct work_struct *work)
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{
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int count = -1;
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unsigned int cpu;
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int nr_cpus;
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struct cpumask online, offline, cpu_online;
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int max_cpus = pm_qos_request(PM_QOS_MAX_ONLINE_CPUS) ? :
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num_present_cpus();
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int min_cpus = pm_qos_request(PM_QOS_MIN_ONLINE_CPUS);
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mutex_lock(&cpuquiet_cpu_lock);
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online = cr_online_requests;
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offline = cr_offline_requests;
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mutex_unlock(&cpuquiet_cpu_lock);
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/* always keep CPU0 online */
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cpumask_set_cpu(0, &online);
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cpu_online = *cpu_online_mask;
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if (max_cpus < min_cpus)
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max_cpus = min_cpus;
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nr_cpus = cpumask_weight(&online);
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if (nr_cpus < min_cpus) {
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cpu = 0;
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count = min_cpus - nr_cpus;
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for (; count > 0; count--) {
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cpu = cpumask_next_zero(cpu, &online);
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cpumask_set_cpu(cpu, &online);
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cpumask_clear_cpu(cpu, &offline);
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}
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} else if (nr_cpus > max_cpus) {
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count = nr_cpus - max_cpus;
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cpu = 1;
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for (; count > 0; count--) {
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/* CPU0 should always be online */
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cpu = cpumask_next(cpu, &online);
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cpumask_set_cpu(cpu, &offline);
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cpumask_clear_cpu(cpu, &online);
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}
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}
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cpumask_andnot(&online, &online, &cpu_online);
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for_each_cpu(cpu, &online)
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cpu_up(cpu);
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cpumask_and(&offline, &offline, &cpu_online);
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for_each_cpu(cpu, &offline)
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cpu_down(cpu);
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wake_up_interruptible(&wait_cpu);
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}
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static int minmax_cpus_notify(struct notifier_block *nb, unsigned long n,
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void *p)
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{
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mutex_lock(&cpuquiet_cpu_lock);
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queue_work(cpuquiet_wq, &cpuquiet_work);
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mutex_unlock(&cpuquiet_cpu_lock);
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return NOTIFY_OK;
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}
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static struct notifier_block minmax_cpus_notifier = {
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.notifier_call = minmax_cpus_notify,
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};
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#ifdef CONFIG_CPU_QUIET_STATS
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CPQ_SIMPLE_ATTRIBUTE(hotplug_timeout, 0644, ulong);
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static struct attribute *cpuquiet_attrs[] = {
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&hotplug_timeout_attr.attr,
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NULL,
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};
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static struct attribute_group cpuquiet_attrs_group = {
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.attrs = cpuquiet_attrs,
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};
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#endif /* CONFIG_CPU_QUIET_STATS */
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int cpuquiet_probe_common(struct platform_device *pdev)
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{
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init_waitqueue_head(&wait_cpu);
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/*
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* Not bound to the issuer CPU (=> high-priority), has rescue worker
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* task, single-threaded, freezable.
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*/
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cpuquiet_wq = alloc_workqueue(
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"cpuquiet", WQ_NON_REENTRANT | WQ_FREEZABLE, 1);
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if (!cpuquiet_wq)
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return -ENOMEM;
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INIT_WORK(&cpuquiet_work, cpuquiet_work_func);
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hotplug_timeout = DEFAULT_HOTPLUG_DELAY_MS;
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cpumask_clear(&cr_online_requests);
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cpumask_clear(&cr_offline_requests);
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if (pm_qos_add_notifier(PM_QOS_MIN_ONLINE_CPUS, &minmax_cpus_notifier))
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pr_err("Failed to register min cpus PM QoS notifier\n");
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if (pm_qos_add_notifier(PM_QOS_MAX_ONLINE_CPUS, &minmax_cpus_notifier))
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pr_err("Failed to register max cpus PM QoS notifier\n");
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return 0;
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}
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EXPORT_SYMBOL(cpuquiet_probe_common);
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#ifdef CONFIG_CPU_QUIET_STATS
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int cpuquiet_probe_common_post(struct platform_device *pdev)
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{
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int err;
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err = cpuquiet_register_attrs(&cpuquiet_attrs_group);
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if (err)
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cpuquiet_remove_common(pdev);
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return err;
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}
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EXPORT_SYMBOL(cpuquiet_probe_common_post);
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#endif
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int cpuquiet_remove_common(struct platform_device *pdev)
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{
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destroy_workqueue(cpuquiet_wq);
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#ifdef CONFIG_CPU_QUIET_STATS
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cpuquiet_unregister_attrs(&cpuquiet_attrs_group);
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#endif
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return 0;
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}
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EXPORT_SYMBOL(cpuquiet_remove_common);
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