[v3] power: add an API to log wakeup reasons

Message ID	1394653598-17143-1-git-send-email-kandoiruchi@google.com (mailing list archive)
State	RFC, archived
Headers	show Return-Path: <linux-pm-owner@kernel.org> From: Ruchi Kandoi <kandoiruchi@google.com> To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: rjw@rjwysocki.net, ghackmann@google.com, john.stultz@linaro.org, toddpoynor@google.com, Ruchi Kandoi <kandoiruchi@google.com> Subject: [PATCH v3] power: add an API to log wakeup reasons Date: Wed, 12 Mar 2014 12:46:38 -0700 Message-Id: <1394653598-17143-1-git-send-email-kandoiruchi@google.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk

diff --git a/include/linux/wakeup_reason.h b/include/linux/wakeup_reason.h new file mode 100644 index 0000000..7ce50f0 --- /dev/null +++ b/include/linux/wakeup_reason.h @@ -0,0 +1,23 @@ +/* + * include/linux/wakeup_reason.h + * + * Logs the reason which caused the kernel to resume + * from the suspend mode. + * + * Copyright (C) 2014 Google, Inc. + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef _LINUX_WAKEUP_REASON_H +#define _LINUX_WAKEUP_REASON_H + +void log_wakeup_reason(int irq); + +#endif /* _LINUX_WAKEUP_REASON_H */ diff --git a/kernel/power/Makefile b/kernel/power/Makefile index 29472bf..f98f021 100644 --- a/kernel/power/Makefile +++ b/kernel/power/Makefile @@ -5,7 +5,7 @@ obj-y += qos.o obj-$(CONFIG_PM) += main.o obj-$(CONFIG_VT_CONSOLE_SLEEP) += console.o obj-$(CONFIG_FREEZER) += process.o -obj-$(CONFIG_SUSPEND) += suspend.o +obj-$(CONFIG_SUSPEND) += suspend.o wakeup_reason.o obj-$(CONFIG_PM_TEST_SUSPEND) += suspend_test.o obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o swap.o user.o \ block_io.o diff --git a/kernel/power/wakeup_reason.c b/kernel/power/wakeup_reason.c new file mode 100644 index 0000000..a21c592 --- /dev/null +++ b/kernel/power/wakeup_reason.c @@ -0,0 +1,141 @@ +/* + * kernel/power/wakeup_reason.c + * + * Logs the reasons which caused the kernel to resume from + * the suspend mode. + * + * Copyright (C) 2014 Google, Inc. + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ +#define pr_fmt(fmt) "wakeup_reason:" fmt + +#include <linux/wakeup_reason.h> +#include <linux/kernel.h> +#include <linux/irq.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kobject.h> +#include <linux/sysfs.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/notifier.h> +#include <linux/suspend.h> + + +#define MAX_WAKEUP_REASON_IRQS 32 +static int irq_list[MAX_WAKEUP_REASON_IRQS]; +static int irqcount; +static struct kobject *wakeup_reason; +static spinlock_t resume_reason_lock; + +static ssize_t reason_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + int irq_no, buf_offset = 0; + struct irq_desc *desc; + spin_lock(&resume_reason_lock); + for (irq_no = 0; irq_no < irqcount; irq_no++) { + desc = irq_to_desc(irq_list[irq_no]); + if (desc && desc->action && desc->action->name) + buf_offset += sprintf(buf + buf_offset, "%d %s\n", + irq_list[irq_no], desc->action->name); + else + buf_offset += sprintf(buf + buf_offset, "%d\n", + irq_list[irq_no]); + } + spin_unlock(&resume_reason_lock); + return buf_offset; +} + +static struct kobj_attribute resume_reason = __ATTR(last_resume_reason, 0666, + reason_show, NULL); + +static struct attribute *attrs[] = { + &resume_reason.attr, + NULL, +}; +static struct attribute_group attr_group = { + .attrs = attrs, +}; + +/* + * logs all the wake up reasons to the kernel + * stores the irqs to expose them to the userspace via sysfs + */ +void log_wakeup_reason(int irq) +{ + struct irq_desc *desc; + desc = irq_to_desc(irq); + if (desc && desc->action && desc->action->name) + pr_info("Resume caused by IRQ %d, %s\n", irq, + desc->action->name); + else + pr_info("Resume caused by IRQ %d\n", irq); + + spin_lock(&resume_reason_lock); + if (irqcount >= MAX_WAKEUP_REASON_IRQS) { + spin_unlock(&resume_reason_lock); + pr_warn("Resume caused by more than %d IRQs\n", + MAX_WAKEUP_REASON_IRQS); + return; + } + + irq_list[irqcount++] = irq; + spin_unlock(&resume_reason_lock); +} + +/* Detects a suspend and clears all the previous wake up reasons*/ +static int wakeup_reason_pm_event(struct notifier_block *notifier, + unsigned long pm_event, void *unused) +{ + switch (pm_event) { + case PM_SUSPEND_PREPARE: + spin_lock(&resume_reason_lock); + irqcount = 0; + spin_unlock(&resume_reason_lock); + break; + default: + break; + } + return NOTIFY_DONE; +} + +static struct notifier_block wakeup_reason_pm_notifier_block = { + .notifier_call = wakeup_reason_pm_event, +}; + +/* Initializes the sysfs parameter + * registers the pm_event notifier + */ +int __init wakeup_reason_init(void) +{ + int retval; + spin_lock_init(&resume_reason_lock); + retval = register_pm_notifier(&wakeup_reason_pm_notifier_block); + if (retval) + pr_warn("%s: failed to register PM notifier %d\n", + __func__, retval); + + wakeup_reason = kobject_create_and_add("wakeup_reasons", kernel_kobj); + if (!wakeup_reason) { + pr_warn("%s: failed to create a sysfs kobject\n", + __func__); + return 1; + } + retval = sysfs_create_group(wakeup_reason, &attr_group); + if (retval) { + kobject_put(wakeup_reason); + pr_warn("%s: failed to create a sysfs group %d\n", + __func__, retval); + } + return 0; +} + +late_initcall(wakeup_reason_init);

[v3] power: add an API to log wakeup reasons

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