v4.19.13 snapshot.
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
new file mode 100644
index 0000000..43d962a
--- /dev/null
+++ b/drivers/rtc/rtc-dev.c
@@ -0,0 +1,483 @@
+/*
+ * RTC subsystem, dev interface
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ *
+ * 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.
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/sched/signal.h>
+#include "rtc-core.h"
+
+static dev_t rtc_devt;
+
+#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
+
+static int rtc_dev_open(struct inode *inode, struct file *file)
+{
+ struct rtc_device *rtc = container_of(inode->i_cdev,
+ struct rtc_device, char_dev);
+
+ if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
+ return -EBUSY;
+
+ file->private_data = rtc;
+
+ spin_lock_irq(&rtc->irq_lock);
+ rtc->irq_data = 0;
+ spin_unlock_irq(&rtc->irq_lock);
+
+ return 0;
+}
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+/*
+ * Routine to poll RTC seconds field for change as often as possible,
+ * after first RTC_UIE use timer to reduce polling
+ */
+static void rtc_uie_task(struct work_struct *work)
+{
+ struct rtc_device *rtc =
+ container_of(work, struct rtc_device, uie_task);
+ struct rtc_time tm;
+ int num = 0;
+ int err;
+
+ err = rtc_read_time(rtc, &tm);
+
+ spin_lock_irq(&rtc->irq_lock);
+ if (rtc->stop_uie_polling || err) {
+ rtc->uie_task_active = 0;
+ } else if (rtc->oldsecs != tm.tm_sec) {
+ num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
+ rtc->oldsecs = tm.tm_sec;
+ rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
+ rtc->uie_timer_active = 1;
+ rtc->uie_task_active = 0;
+ add_timer(&rtc->uie_timer);
+ } else if (schedule_work(&rtc->uie_task) == 0) {
+ rtc->uie_task_active = 0;
+ }
+ spin_unlock_irq(&rtc->irq_lock);
+ if (num)
+ rtc_handle_legacy_irq(rtc, num, RTC_UF);
+}
+static void rtc_uie_timer(struct timer_list *t)
+{
+ struct rtc_device *rtc = from_timer(rtc, t, uie_timer);
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc->irq_lock, flags);
+ rtc->uie_timer_active = 0;
+ rtc->uie_task_active = 1;
+ if ((schedule_work(&rtc->uie_task) == 0))
+ rtc->uie_task_active = 0;
+ spin_unlock_irqrestore(&rtc->irq_lock, flags);
+}
+
+static int clear_uie(struct rtc_device *rtc)
+{
+ spin_lock_irq(&rtc->irq_lock);
+ if (rtc->uie_irq_active) {
+ rtc->stop_uie_polling = 1;
+ if (rtc->uie_timer_active) {
+ spin_unlock_irq(&rtc->irq_lock);
+ del_timer_sync(&rtc->uie_timer);
+ spin_lock_irq(&rtc->irq_lock);
+ rtc->uie_timer_active = 0;
+ }
+ if (rtc->uie_task_active) {
+ spin_unlock_irq(&rtc->irq_lock);
+ flush_scheduled_work();
+ spin_lock_irq(&rtc->irq_lock);
+ }
+ rtc->uie_irq_active = 0;
+ }
+ spin_unlock_irq(&rtc->irq_lock);
+ return 0;
+}
+
+static int set_uie(struct rtc_device *rtc)
+{
+ struct rtc_time tm;
+ int err;
+
+ err = rtc_read_time(rtc, &tm);
+ if (err)
+ return err;
+ spin_lock_irq(&rtc->irq_lock);
+ if (!rtc->uie_irq_active) {
+ rtc->uie_irq_active = 1;
+ rtc->stop_uie_polling = 0;
+ rtc->oldsecs = tm.tm_sec;
+ rtc->uie_task_active = 1;
+ if (schedule_work(&rtc->uie_task) == 0)
+ rtc->uie_task_active = 0;
+ }
+ rtc->irq_data = 0;
+ spin_unlock_irq(&rtc->irq_lock);
+ return 0;
+}
+
+int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
+{
+ if (enabled)
+ return set_uie(rtc);
+ else
+ return clear_uie(rtc);
+}
+EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
+
+#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
+
+static ssize_t
+rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ struct rtc_device *rtc = file->private_data;
+
+ DECLARE_WAITQUEUE(wait, current);
+ unsigned long data;
+ ssize_t ret;
+
+ if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
+ return -EINVAL;
+
+ add_wait_queue(&rtc->irq_queue, &wait);
+ do {
+ __set_current_state(TASK_INTERRUPTIBLE);
+
+ spin_lock_irq(&rtc->irq_lock);
+ data = rtc->irq_data;
+ rtc->irq_data = 0;
+ spin_unlock_irq(&rtc->irq_lock);
+
+ if (data != 0) {
+ ret = 0;
+ break;
+ }
+ if (file->f_flags & O_NONBLOCK) {
+ ret = -EAGAIN;
+ break;
+ }
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ } while (1);
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&rtc->irq_queue, &wait);
+
+ if (ret == 0) {
+ /* Check for any data updates */
+ if (rtc->ops->read_callback)
+ data = rtc->ops->read_callback(rtc->dev.parent,
+ data);
+
+ if (sizeof(int) != sizeof(long) &&
+ count == sizeof(unsigned int))
+ ret = put_user(data, (unsigned int __user *)buf) ?:
+ sizeof(unsigned int);
+ else
+ ret = put_user(data, (unsigned long __user *)buf) ?:
+ sizeof(unsigned long);
+ }
+ return ret;
+}
+
+static __poll_t rtc_dev_poll(struct file *file, poll_table *wait)
+{
+ struct rtc_device *rtc = file->private_data;
+ unsigned long data;
+
+ poll_wait(file, &rtc->irq_queue, wait);
+
+ data = rtc->irq_data;
+
+ return (data != 0) ? (EPOLLIN | EPOLLRDNORM) : 0;
+}
+
+static long rtc_dev_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int err = 0;
+ struct rtc_device *rtc = file->private_data;
+ const struct rtc_class_ops *ops = rtc->ops;
+ struct rtc_time tm;
+ struct rtc_wkalrm alarm;
+ void __user *uarg = (void __user *) arg;
+
+ err = mutex_lock_interruptible(&rtc->ops_lock);
+ if (err)
+ return err;
+
+ /* check that the calling task has appropriate permissions
+ * for certain ioctls. doing this check here is useful
+ * to avoid duplicate code in each driver.
+ */
+ switch (cmd) {
+ case RTC_EPOCH_SET:
+ case RTC_SET_TIME:
+ if (!capable(CAP_SYS_TIME))
+ err = -EACCES;
+ break;
+
+ case RTC_IRQP_SET:
+ if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
+ err = -EACCES;
+ break;
+
+ case RTC_PIE_ON:
+ if (rtc->irq_freq > rtc->max_user_freq &&
+ !capable(CAP_SYS_RESOURCE))
+ err = -EACCES;
+ break;
+ }
+
+ if (err)
+ goto done;
+
+ /*
+ * Drivers *SHOULD NOT* provide ioctl implementations
+ * for these requests. Instead, provide methods to
+ * support the following code, so that the RTC's main
+ * features are accessible without using ioctls.
+ *
+ * RTC and alarm times will be in UTC, by preference,
+ * but dual-booting with MS-Windows implies RTCs must
+ * use the local wall clock time.
+ */
+
+ switch (cmd) {
+ case RTC_ALM_READ:
+ mutex_unlock(&rtc->ops_lock);
+
+ err = rtc_read_alarm(rtc, &alarm);
+ if (err < 0)
+ return err;
+
+ if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
+ err = -EFAULT;
+ return err;
+
+ case RTC_ALM_SET:
+ mutex_unlock(&rtc->ops_lock);
+
+ if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
+ return -EFAULT;
+
+ alarm.enabled = 0;
+ alarm.pending = 0;
+ alarm.time.tm_wday = -1;
+ alarm.time.tm_yday = -1;
+ alarm.time.tm_isdst = -1;
+
+ /* RTC_ALM_SET alarms may be up to 24 hours in the future.
+ * Rather than expecting every RTC to implement "don't care"
+ * for day/month/year fields, just force the alarm to have
+ * the right values for those fields.
+ *
+ * RTC_WKALM_SET should be used instead. Not only does it
+ * eliminate the need for a separate RTC_AIE_ON call, it
+ * doesn't have the "alarm 23:59:59 in the future" race.
+ *
+ * NOTE: some legacy code may have used invalid fields as
+ * wildcards, exposing hardware "periodic alarm" capabilities.
+ * Not supported here.
+ */
+ {
+ time64_t now, then;
+
+ err = rtc_read_time(rtc, &tm);
+ if (err < 0)
+ return err;
+ now = rtc_tm_to_time64(&tm);
+
+ alarm.time.tm_mday = tm.tm_mday;
+ alarm.time.tm_mon = tm.tm_mon;
+ alarm.time.tm_year = tm.tm_year;
+ err = rtc_valid_tm(&alarm.time);
+ if (err < 0)
+ return err;
+ then = rtc_tm_to_time64(&alarm.time);
+
+ /* alarm may need to wrap into tomorrow */
+ if (then < now) {
+ rtc_time64_to_tm(now + 24 * 60 * 60, &tm);
+ alarm.time.tm_mday = tm.tm_mday;
+ alarm.time.tm_mon = tm.tm_mon;
+ alarm.time.tm_year = tm.tm_year;
+ }
+ }
+
+ return rtc_set_alarm(rtc, &alarm);
+
+ case RTC_RD_TIME:
+ mutex_unlock(&rtc->ops_lock);
+
+ err = rtc_read_time(rtc, &tm);
+ if (err < 0)
+ return err;
+
+ if (copy_to_user(uarg, &tm, sizeof(tm)))
+ err = -EFAULT;
+ return err;
+
+ case RTC_SET_TIME:
+ mutex_unlock(&rtc->ops_lock);
+
+ if (copy_from_user(&tm, uarg, sizeof(tm)))
+ return -EFAULT;
+
+ return rtc_set_time(rtc, &tm);
+
+ case RTC_PIE_ON:
+ err = rtc_irq_set_state(rtc, 1);
+ break;
+
+ case RTC_PIE_OFF:
+ err = rtc_irq_set_state(rtc, 0);
+ break;
+
+ case RTC_AIE_ON:
+ mutex_unlock(&rtc->ops_lock);
+ return rtc_alarm_irq_enable(rtc, 1);
+
+ case RTC_AIE_OFF:
+ mutex_unlock(&rtc->ops_lock);
+ return rtc_alarm_irq_enable(rtc, 0);
+
+ case RTC_UIE_ON:
+ mutex_unlock(&rtc->ops_lock);
+ return rtc_update_irq_enable(rtc, 1);
+
+ case RTC_UIE_OFF:
+ mutex_unlock(&rtc->ops_lock);
+ return rtc_update_irq_enable(rtc, 0);
+
+ case RTC_IRQP_SET:
+ err = rtc_irq_set_freq(rtc, arg);
+ break;
+
+ case RTC_IRQP_READ:
+ err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
+ break;
+
+ case RTC_WKALM_SET:
+ mutex_unlock(&rtc->ops_lock);
+ if (copy_from_user(&alarm, uarg, sizeof(alarm)))
+ return -EFAULT;
+
+ return rtc_set_alarm(rtc, &alarm);
+
+ case RTC_WKALM_RD:
+ mutex_unlock(&rtc->ops_lock);
+ err = rtc_read_alarm(rtc, &alarm);
+ if (err < 0)
+ return err;
+
+ if (copy_to_user(uarg, &alarm, sizeof(alarm)))
+ err = -EFAULT;
+ return err;
+
+ default:
+ /* Finally try the driver's ioctl interface */
+ if (ops->ioctl) {
+ err = ops->ioctl(rtc->dev.parent, cmd, arg);
+ if (err == -ENOIOCTLCMD)
+ err = -ENOTTY;
+ } else
+ err = -ENOTTY;
+ break;
+ }
+
+done:
+ mutex_unlock(&rtc->ops_lock);
+ return err;
+}
+
+static int rtc_dev_fasync(int fd, struct file *file, int on)
+{
+ struct rtc_device *rtc = file->private_data;
+ return fasync_helper(fd, file, on, &rtc->async_queue);
+}
+
+static int rtc_dev_release(struct inode *inode, struct file *file)
+{
+ struct rtc_device *rtc = file->private_data;
+
+ /* We shut down the repeating IRQs that userspace enabled,
+ * since nothing is listening to them.
+ * - Update (UIE) ... currently only managed through ioctls
+ * - Periodic (PIE) ... also used through rtc_*() interface calls
+ *
+ * Leave the alarm alone; it may be set to trigger a system wakeup
+ * later, or be used by kernel code, and is a one-shot event anyway.
+ */
+
+ /* Keep ioctl until all drivers are converted */
+ rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
+ rtc_update_irq_enable(rtc, 0);
+ rtc_irq_set_state(rtc, 0);
+
+ clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
+ return 0;
+}
+
+static const struct file_operations rtc_dev_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = rtc_dev_read,
+ .poll = rtc_dev_poll,
+ .unlocked_ioctl = rtc_dev_ioctl,
+ .open = rtc_dev_open,
+ .release = rtc_dev_release,
+ .fasync = rtc_dev_fasync,
+};
+
+/* insertion/removal hooks */
+
+void rtc_dev_prepare(struct rtc_device *rtc)
+{
+ if (!rtc_devt)
+ return;
+
+ if (rtc->id >= RTC_DEV_MAX) {
+ dev_dbg(&rtc->dev, "too many RTC devices\n");
+ return;
+ }
+
+ rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+ INIT_WORK(&rtc->uie_task, rtc_uie_task);
+ timer_setup(&rtc->uie_timer, rtc_uie_timer, 0);
+#endif
+
+ cdev_init(&rtc->char_dev, &rtc_dev_fops);
+ rtc->char_dev.owner = rtc->owner;
+}
+
+void __init rtc_dev_init(void)
+{
+ int err;
+
+ err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
+ if (err < 0)
+ pr_err("failed to allocate char dev region\n");
+}
+
+void __exit rtc_dev_exit(void)
+{
+ if (rtc_devt)
+ unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
+}