staging: android-alarm: Add android alarm driver & in-kernel alarm interface

Drivers can now create alarms that will use an hrtimer while the
system is running and the rtc to wake up from suspend.

CC: Arve Hjønnevåg <arve@android.com>
CC: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
[Fold and move alarm driver and interface to staging,
 fix whitespace issue, drop kconfig & make file changes
 as it currently doesn't build  -jstultz]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/alarm-dev.c

+/* drivers/rtc/alarm-dev.c
+ *
+ * Copyright (C) 2007-2009 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.
+ *
+ */
+
+#include <asm/mach/time.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/sysdev.h>
+#include <linux/uaccess.h>
+#include <linux/wakelock.h>
+#include "android_alarm.h"
+
+#define ANDROID_ALARM_PRINT_INFO (1U << 0)
+#define ANDROID_ALARM_PRINT_IO (1U << 1)
+#define ANDROID_ALARM_PRINT_INT (1U << 2)
+
+static int debug_mask = ANDROID_ALARM_PRINT_INFO;
+module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+#define pr_alarm(debug_level_mask, args...) \
+	do { \
+		if (debug_mask & ANDROID_ALARM_PRINT_##debug_level_mask) { \
+			pr_info(args); \
+		} \
+	} while (0)
+
+#define ANDROID_ALARM_WAKEUP_MASK ( \
+	ANDROID_ALARM_RTC_WAKEUP_MASK | \
+	ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK)
+
+/* support old usespace code */
+#define ANDROID_ALARM_SET_OLD               _IOW('a', 2, time_t) /* set alarm */
+#define ANDROID_ALARM_SET_AND_WAIT_OLD      _IOW('a', 3, time_t)
+
+static int alarm_opened;
+static DEFINE_SPINLOCK(alarm_slock);
+static struct wake_lock alarm_wake_lock;
+static DECLARE_WAIT_QUEUE_HEAD(alarm_wait_queue);
+static uint32_t alarm_pending;
+static uint32_t alarm_enabled;
+static uint32_t wait_pending;
+
+static struct alarm alarms[ANDROID_ALARM_TYPE_COUNT];
+
+static long alarm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int rv = 0;
+	unsigned long flags;
+	struct timespec new_alarm_time;
+	struct timespec new_rtc_time;
+	struct timespec tmp_time;
+	enum android_alarm_type alarm_type = ANDROID_ALARM_IOCTL_TO_TYPE(cmd);
+	uint32_t alarm_type_mask = 1U << alarm_type;
+
+	if (alarm_type >= ANDROID_ALARM_TYPE_COUNT)
+		return -EINVAL;
+
+	if (ANDROID_ALARM_BASE_CMD(cmd) != ANDROID_ALARM_GET_TIME(0)) {
+		if ((file->f_flags & O_ACCMODE) == O_RDONLY)
+			return -EPERM;
+		if (file->private_data == NULL &&
+		    cmd != ANDROID_ALARM_SET_RTC) {
+			spin_lock_irqsave(&alarm_slock, flags);
+			if (alarm_opened) {
+				spin_unlock_irqrestore(&alarm_slock, flags);
+				return -EBUSY;
+			}
+			alarm_opened = 1;
+			file->private_data = (void *)1;
+			spin_unlock_irqrestore(&alarm_slock, flags);
+		}
+	}
+
+	switch (ANDROID_ALARM_BASE_CMD(cmd)) {
+	case ANDROID_ALARM_CLEAR(0):
+		spin_lock_irqsave(&alarm_slock, flags);
+		pr_alarm(IO, "alarm %d clear\n", alarm_type);
+		alarm_try_to_cancel(&alarms[alarm_type]);
+		if (alarm_pending) {
+			alarm_pending &= ~alarm_type_mask;
+			if (!alarm_pending && !wait_pending)
+				wake_unlock(&alarm_wake_lock);
+		}
+		alarm_enabled &= ~alarm_type_mask;
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		break;
+
+	case ANDROID_ALARM_SET_OLD:
+	case ANDROID_ALARM_SET_AND_WAIT_OLD:
+		if (get_user(new_alarm_time.tv_sec, (int __user *)arg)) {
+			rv = -EFAULT;
+			goto err1;
+		}
+		new_alarm_time.tv_nsec = 0;
+		goto from_old_alarm_set;
+
+	case ANDROID_ALARM_SET_AND_WAIT(0):
+	case ANDROID_ALARM_SET(0):
+		if (copy_from_user(&new_alarm_time, (void __user *)arg,
+		    sizeof(new_alarm_time))) {
+			rv = -EFAULT;
+			goto err1;
+		}
+from_old_alarm_set:
+		spin_lock_irqsave(&alarm_slock, flags);
+		pr_alarm(IO, "alarm %d set %ld.%09ld\n", alarm_type,
+			new_alarm_time.tv_sec, new_alarm_time.tv_nsec);
+		alarm_enabled |= alarm_type_mask;
+		alarm_start_range(&alarms[alarm_type],
+			timespec_to_ktime(new_alarm_time),
+			timespec_to_ktime(new_alarm_time));
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		if (ANDROID_ALARM_BASE_CMD(cmd) != ANDROID_ALARM_SET_AND_WAIT(0)
+		    && cmd != ANDROID_ALARM_SET_AND_WAIT_OLD)
+			break;
+		/* fall though */
+	case ANDROID_ALARM_WAIT:
+		spin_lock_irqsave(&alarm_slock, flags);
+		pr_alarm(IO, "alarm wait\n");
+		if (!alarm_pending && wait_pending) {
+			wake_unlock(&alarm_wake_lock);
+			wait_pending = 0;
+		}
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		rv = wait_event_interruptible(alarm_wait_queue, alarm_pending);
+		if (rv)
+			goto err1;
+		spin_lock_irqsave(&alarm_slock, flags);
+		rv = alarm_pending;
+		wait_pending = 1;
+		alarm_pending = 0;
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		break;
+	case ANDROID_ALARM_SET_RTC:
+		if (copy_from_user(&new_rtc_time, (void __user *)arg,
+		    sizeof(new_rtc_time))) {
+			rv = -EFAULT;
+			goto err1;
+		}
+		rv = alarm_set_rtc(new_rtc_time);
+		spin_lock_irqsave(&alarm_slock, flags);
+		alarm_pending |= ANDROID_ALARM_TIME_CHANGE_MASK;
+		wake_up(&alarm_wait_queue);
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		if (rv < 0)
+			goto err1;
+		break;
+	case ANDROID_ALARM_GET_TIME(0):
+		switch (alarm_type) {
+		case ANDROID_ALARM_RTC_WAKEUP:
+		case ANDROID_ALARM_RTC:
+			getnstimeofday(&tmp_time);
+			break;
+		case ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP:
+		case ANDROID_ALARM_ELAPSED_REALTIME:
+			tmp_time =
+				ktime_to_timespec(alarm_get_elapsed_realtime());
+			break;
+		case ANDROID_ALARM_TYPE_COUNT:
+		case ANDROID_ALARM_SYSTEMTIME:
+			ktime_get_ts(&tmp_time);
+			break;
+		}
+		if (copy_to_user((void __user *)arg, &tmp_time,
+		    sizeof(tmp_time))) {
+			rv = -EFAULT;
+			goto err1;
+		}
+		break;
+
+	default:
+		rv = -EINVAL;
+		goto err1;
+	}
+err1:
+	return rv;
+}
+
+static int alarm_open(struct inode *inode, struct file *file)
+{
+	file->private_data = NULL;
+	return 0;
+}
+
+static int alarm_release(struct inode *inode, struct file *file)
+{
+	int i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&alarm_slock, flags);
+	if (file->private_data != 0) {
+		for (i = 0; i < ANDROID_ALARM_TYPE_COUNT; i++) {
+			uint32_t alarm_type_mask = 1U << i;
+			if (alarm_enabled & alarm_type_mask) {
+				pr_alarm(INFO, "alarm_release: clear alarm, "
+					"pending %d\n",
+					!!(alarm_pending & alarm_type_mask));
+				alarm_enabled &= ~alarm_type_mask;
+			}
+			spin_unlock_irqrestore(&alarm_slock, flags);
+			alarm_cancel(&alarms[i]);
+			spin_lock_irqsave(&alarm_slock, flags);
+		}
+		if (alarm_pending | wait_pending) {
+			if (alarm_pending)
+				pr_alarm(INFO, "alarm_release: clear "
+					"pending alarms %x\n", alarm_pending);
+			wake_unlock(&alarm_wake_lock);
+			wait_pending = 0;
+			alarm_pending = 0;
+		}
+		alarm_opened = 0;
+	}
+	spin_unlock_irqrestore(&alarm_slock, flags);
+	return 0;
+}
+
+static void alarm_triggered(struct alarm *alarm)
+{
+	unsigned long flags;
+	uint32_t alarm_type_mask = 1U << alarm->type;
+
+	pr_alarm(INT, "alarm_triggered type %d\n", alarm->type);
+	spin_lock_irqsave(&alarm_slock, flags);
+	if (alarm_enabled & alarm_type_mask) {
+		wake_lock_timeout(&alarm_wake_lock, 5 * HZ);
+		alarm_enabled &= ~alarm_type_mask;
+		alarm_pending |= alarm_type_mask;
+		wake_up(&alarm_wait_queue);
+	}
+	spin_unlock_irqrestore(&alarm_slock, flags);
+}
+
+static const struct file_operations alarm_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = alarm_ioctl,
+	.open = alarm_open,
+	.release = alarm_release,
+};
+
+static struct miscdevice alarm_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "alarm",
+	.fops = &alarm_fops,
+};
+
+static int __init alarm_dev_init(void)
+{
+	int err;
+	int i;
+
+	err = misc_register(&alarm_device);
+	if (err)
+		return err;
+
+	for (i = 0; i < ANDROID_ALARM_TYPE_COUNT; i++)
+		alarm_init(&alarms[i], i, alarm_triggered);
+	wake_lock_init(&alarm_wake_lock, WAKE_LOCK_SUSPEND, "alarm");
+
+	return 0;
+}
+
+static void  __exit alarm_dev_exit(void)
+{
+	misc_deregister(&alarm_device);
+	wake_lock_destroy(&alarm_wake_lock);
+}
+
+module_init(alarm_dev_init);
+module_exit(alarm_dev_exit);
+

drivers/staging/android/android_alarm.h

+/* include/linux/android_alarm.h
+ *
+ * Copyright (C) 2006-2007 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_ANDROID_ALARM_H
+#define _LINUX_ANDROID_ALARM_H
+
+#include <linux/ioctl.h>
+#include <linux/time.h>
+
+enum android_alarm_type {
+	/* return code bit numbers or set alarm arg */
+	ANDROID_ALARM_RTC_WAKEUP,
+	ANDROID_ALARM_RTC,
+	ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP,
+	ANDROID_ALARM_ELAPSED_REALTIME,
+	ANDROID_ALARM_SYSTEMTIME,
+
+	ANDROID_ALARM_TYPE_COUNT,
+
+	/* return code bit numbers */
+	/* ANDROID_ALARM_TIME_CHANGE = 16 */
+};
+
+#ifdef __KERNEL__
+
+#include <linux/ktime.h>
+#include <linux/rbtree.h>
+
+/*
+ * The alarm interface is similar to the hrtimer interface but adds support
+ * for wakeup from suspend. It also adds an elapsed realtime clock that can
+ * be used for periodic timers that need to keep runing while the system is
+ * suspended and not be disrupted when the wall time is set.
+ */
+
+/**
+ * struct alarm - the basic alarm structure
+ * @node:	red black tree node for time ordered insertion
+ * @type:	alarm type. rtc/elapsed-realtime/systemtime, wakeup/non-wakeup.
+ * @softexpires: the absolute earliest expiry time of the alarm.
+ * @expires:	the absolute expiry time.
+ * @function:	alarm expiry callback function
+ *
+ * The alarm structure must be initialized by alarm_init()
+ *
+ */
+
+struct alarm {
+	struct rb_node		node;
+	enum android_alarm_type type;
+	ktime_t			softexpires;
+	ktime_t			expires;
+	void			(*function)(struct alarm *);
+};
+
+void alarm_init(struct alarm *alarm,
+	enum android_alarm_type type, void (*function)(struct alarm *));
+void alarm_start_range(struct alarm *alarm, ktime_t start, ktime_t end);
+int alarm_try_to_cancel(struct alarm *alarm);
+int alarm_cancel(struct alarm *alarm);
+ktime_t alarm_get_elapsed_realtime(void);
+
+/* set rtc while preserving elapsed realtime */
+int alarm_set_rtc(const struct timespec ts);
+
+#endif
+
+enum android_alarm_return_flags {
+	ANDROID_ALARM_RTC_WAKEUP_MASK = 1U << ANDROID_ALARM_RTC_WAKEUP,
+	ANDROID_ALARM_RTC_MASK = 1U << ANDROID_ALARM_RTC,
+	ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK =
+				1U << ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP,
+	ANDROID_ALARM_ELAPSED_REALTIME_MASK =
+				1U << ANDROID_ALARM_ELAPSED_REALTIME,
+	ANDROID_ALARM_SYSTEMTIME_MASK = 1U << ANDROID_ALARM_SYSTEMTIME,
+	ANDROID_ALARM_TIME_CHANGE_MASK = 1U << 16
+};
+
+/* Disable alarm */
+#define ANDROID_ALARM_CLEAR(type)           _IO('a', 0 | ((type) << 4))
+
+/* Ack last alarm and wait for next */
+#define ANDROID_ALARM_WAIT                  _IO('a', 1)
+
+#define ALARM_IOW(c, type, size)            _IOW('a', (c) | ((type) << 4), size)
+/* Set alarm */
+#define ANDROID_ALARM_SET(type)             ALARM_IOW(2, type, struct timespec)
+#define ANDROID_ALARM_SET_AND_WAIT(type)    ALARM_IOW(3, type, struct timespec)
+#define ANDROID_ALARM_GET_TIME(type)        ALARM_IOW(4, type, struct timespec)
+#define ANDROID_ALARM_SET_RTC               _IOW('a', 5, struct timespec)
+#define ANDROID_ALARM_BASE_CMD(cmd)         (cmd & ~(_IOC(0, 0, 0xf0, 0)))
+#define ANDROID_ALARM_IOCTL_TO_TYPE(cmd)    (_IOC_NR(cmd) >> 4)
+
+#endif