575 lines
13 KiB
C
575 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* RTC subsystem, dev interface
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*
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* Copyright (C) 2005 Tower Technologies
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* Author: Alessandro Zummo <a.zummo@towertech.it>
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*
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* based on arch/arm/common/rtctime.c
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/compat.h>
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#include <linux/module.h>
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#include <linux/rtc.h>
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#include <linux/sched/signal.h>
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#include "rtc-core.h"
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static dev_t rtc_devt;
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#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
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static int rtc_dev_open(struct inode *inode, struct file *file)
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{
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struct rtc_device *rtc = container_of(inode->i_cdev,
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struct rtc_device, char_dev);
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if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
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return -EBUSY;
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file->private_data = rtc;
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spin_lock_irq(&rtc->irq_lock);
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rtc->irq_data = 0;
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spin_unlock_irq(&rtc->irq_lock);
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return 0;
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}
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#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
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/*
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* Routine to poll RTC seconds field for change as often as possible,
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* after first RTC_UIE use timer to reduce polling
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*/
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static void rtc_uie_task(struct work_struct *work)
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{
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struct rtc_device *rtc =
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container_of(work, struct rtc_device, uie_task);
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struct rtc_time tm;
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int num = 0;
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int err;
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err = rtc_read_time(rtc, &tm);
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spin_lock_irq(&rtc->irq_lock);
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if (rtc->stop_uie_polling || err) {
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rtc->uie_task_active = 0;
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} else if (rtc->oldsecs != tm.tm_sec) {
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num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
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rtc->oldsecs = tm.tm_sec;
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rtc->uie_timer.expires = jiffies + HZ - (HZ / 10);
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rtc->uie_timer_active = 1;
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rtc->uie_task_active = 0;
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add_timer(&rtc->uie_timer);
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} else if (schedule_work(&rtc->uie_task) == 0) {
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rtc->uie_task_active = 0;
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}
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spin_unlock_irq(&rtc->irq_lock);
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if (num)
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rtc_handle_legacy_irq(rtc, num, RTC_UF);
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}
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static void rtc_uie_timer(struct timer_list *t)
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{
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struct rtc_device *rtc = from_timer(rtc, t, uie_timer);
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unsigned long flags;
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spin_lock_irqsave(&rtc->irq_lock, flags);
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rtc->uie_timer_active = 0;
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rtc->uie_task_active = 1;
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if ((schedule_work(&rtc->uie_task) == 0))
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rtc->uie_task_active = 0;
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spin_unlock_irqrestore(&rtc->irq_lock, flags);
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}
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static int clear_uie(struct rtc_device *rtc)
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{
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spin_lock_irq(&rtc->irq_lock);
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if (rtc->uie_irq_active) {
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rtc->stop_uie_polling = 1;
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if (rtc->uie_timer_active) {
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spin_unlock_irq(&rtc->irq_lock);
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del_timer_sync(&rtc->uie_timer);
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spin_lock_irq(&rtc->irq_lock);
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rtc->uie_timer_active = 0;
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}
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if (rtc->uie_task_active) {
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spin_unlock_irq(&rtc->irq_lock);
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flush_scheduled_work();
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spin_lock_irq(&rtc->irq_lock);
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}
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rtc->uie_irq_active = 0;
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}
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spin_unlock_irq(&rtc->irq_lock);
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return 0;
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}
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static int set_uie(struct rtc_device *rtc)
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{
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struct rtc_time tm;
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int err;
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err = rtc_read_time(rtc, &tm);
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if (err)
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return err;
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spin_lock_irq(&rtc->irq_lock);
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if (!rtc->uie_irq_active) {
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rtc->uie_irq_active = 1;
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rtc->stop_uie_polling = 0;
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rtc->oldsecs = tm.tm_sec;
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rtc->uie_task_active = 1;
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if (schedule_work(&rtc->uie_task) == 0)
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rtc->uie_task_active = 0;
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}
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rtc->irq_data = 0;
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spin_unlock_irq(&rtc->irq_lock);
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return 0;
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}
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int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
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{
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if (enabled)
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return set_uie(rtc);
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else
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return clear_uie(rtc);
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}
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EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
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#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
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static ssize_t
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rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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struct rtc_device *rtc = file->private_data;
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DECLARE_WAITQUEUE(wait, current);
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unsigned long data;
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ssize_t ret;
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if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
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return -EINVAL;
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add_wait_queue(&rtc->irq_queue, &wait);
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do {
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__set_current_state(TASK_INTERRUPTIBLE);
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spin_lock_irq(&rtc->irq_lock);
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data = rtc->irq_data;
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rtc->irq_data = 0;
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spin_unlock_irq(&rtc->irq_lock);
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if (data != 0) {
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ret = 0;
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break;
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}
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if (file->f_flags & O_NONBLOCK) {
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ret = -EAGAIN;
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break;
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}
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if (signal_pending(current)) {
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ret = -ERESTARTSYS;
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break;
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}
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schedule();
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} while (1);
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&rtc->irq_queue, &wait);
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if (ret == 0) {
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if (sizeof(int) != sizeof(long) &&
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count == sizeof(unsigned int))
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ret = put_user(data, (unsigned int __user *)buf) ?:
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sizeof(unsigned int);
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else
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ret = put_user(data, (unsigned long __user *)buf) ?:
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sizeof(unsigned long);
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}
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return ret;
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}
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static __poll_t rtc_dev_poll(struct file *file, poll_table *wait)
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{
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struct rtc_device *rtc = file->private_data;
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unsigned long data;
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poll_wait(file, &rtc->irq_queue, wait);
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data = rtc->irq_data;
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return (data != 0) ? (EPOLLIN | EPOLLRDNORM) : 0;
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}
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static long rtc_dev_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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int err = 0;
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struct rtc_device *rtc = file->private_data;
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const struct rtc_class_ops *ops = rtc->ops;
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struct rtc_time tm;
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struct rtc_wkalrm alarm;
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struct rtc_param param;
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void __user *uarg = (void __user *)arg;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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/* check that the calling task has appropriate permissions
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* for certain ioctls. doing this check here is useful
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* to avoid duplicate code in each driver.
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*/
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switch (cmd) {
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case RTC_EPOCH_SET:
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case RTC_SET_TIME:
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case RTC_PARAM_SET:
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if (!capable(CAP_SYS_TIME))
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err = -EACCES;
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break;
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case RTC_IRQP_SET:
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if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
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err = -EACCES;
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break;
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case RTC_PIE_ON:
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if (rtc->irq_freq > rtc->max_user_freq &&
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!capable(CAP_SYS_RESOURCE))
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err = -EACCES;
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break;
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}
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if (err)
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goto done;
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/*
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* Drivers *SHOULD NOT* provide ioctl implementations
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* for these requests. Instead, provide methods to
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* support the following code, so that the RTC's main
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* features are accessible without using ioctls.
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*
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* RTC and alarm times will be in UTC, by preference,
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* but dual-booting with MS-Windows implies RTCs must
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* use the local wall clock time.
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*/
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switch (cmd) {
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case RTC_ALM_READ:
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mutex_unlock(&rtc->ops_lock);
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err = rtc_read_alarm(rtc, &alarm);
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if (err < 0)
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return err;
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if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
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err = -EFAULT;
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return err;
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case RTC_ALM_SET:
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mutex_unlock(&rtc->ops_lock);
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if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
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return -EFAULT;
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alarm.enabled = 0;
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alarm.pending = 0;
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alarm.time.tm_wday = -1;
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alarm.time.tm_yday = -1;
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alarm.time.tm_isdst = -1;
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/* RTC_ALM_SET alarms may be up to 24 hours in the future.
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* Rather than expecting every RTC to implement "don't care"
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* for day/month/year fields, just force the alarm to have
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* the right values for those fields.
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*
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* RTC_WKALM_SET should be used instead. Not only does it
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* eliminate the need for a separate RTC_AIE_ON call, it
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* doesn't have the "alarm 23:59:59 in the future" race.
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*
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* NOTE: some legacy code may have used invalid fields as
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* wildcards, exposing hardware "periodic alarm" capabilities.
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* Not supported here.
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*/
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{
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time64_t now, then;
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err = rtc_read_time(rtc, &tm);
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if (err < 0)
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return err;
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now = rtc_tm_to_time64(&tm);
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alarm.time.tm_mday = tm.tm_mday;
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alarm.time.tm_mon = tm.tm_mon;
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alarm.time.tm_year = tm.tm_year;
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err = rtc_valid_tm(&alarm.time);
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if (err < 0)
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return err;
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then = rtc_tm_to_time64(&alarm.time);
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/* alarm may need to wrap into tomorrow */
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if (then < now) {
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rtc_time64_to_tm(now + 24 * 60 * 60, &tm);
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alarm.time.tm_mday = tm.tm_mday;
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alarm.time.tm_mon = tm.tm_mon;
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alarm.time.tm_year = tm.tm_year;
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}
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}
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return rtc_set_alarm(rtc, &alarm);
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case RTC_RD_TIME:
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mutex_unlock(&rtc->ops_lock);
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err = rtc_read_time(rtc, &tm);
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if (err < 0)
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return err;
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if (copy_to_user(uarg, &tm, sizeof(tm)))
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err = -EFAULT;
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return err;
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case RTC_SET_TIME:
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mutex_unlock(&rtc->ops_lock);
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if (copy_from_user(&tm, uarg, sizeof(tm)))
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return -EFAULT;
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return rtc_set_time(rtc, &tm);
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case RTC_PIE_ON:
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err = rtc_irq_set_state(rtc, 1);
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break;
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case RTC_PIE_OFF:
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err = rtc_irq_set_state(rtc, 0);
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break;
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case RTC_AIE_ON:
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mutex_unlock(&rtc->ops_lock);
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return rtc_alarm_irq_enable(rtc, 1);
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case RTC_AIE_OFF:
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mutex_unlock(&rtc->ops_lock);
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return rtc_alarm_irq_enable(rtc, 0);
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case RTC_UIE_ON:
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mutex_unlock(&rtc->ops_lock);
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return rtc_update_irq_enable(rtc, 1);
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case RTC_UIE_OFF:
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mutex_unlock(&rtc->ops_lock);
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return rtc_update_irq_enable(rtc, 0);
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case RTC_IRQP_SET:
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err = rtc_irq_set_freq(rtc, arg);
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break;
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case RTC_IRQP_READ:
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err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
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break;
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case RTC_WKALM_SET:
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mutex_unlock(&rtc->ops_lock);
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if (copy_from_user(&alarm, uarg, sizeof(alarm)))
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return -EFAULT;
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return rtc_set_alarm(rtc, &alarm);
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case RTC_WKALM_RD:
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mutex_unlock(&rtc->ops_lock);
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err = rtc_read_alarm(rtc, &alarm);
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if (err < 0)
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return err;
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if (copy_to_user(uarg, &alarm, sizeof(alarm)))
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err = -EFAULT;
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return err;
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case RTC_PARAM_GET:
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if (copy_from_user(¶m, uarg, sizeof(param))) {
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mutex_unlock(&rtc->ops_lock);
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return -EFAULT;
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}
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switch(param.param) {
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case RTC_PARAM_FEATURES:
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if (param.index != 0)
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err = -EINVAL;
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param.uvalue = rtc->features[0];
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break;
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case RTC_PARAM_CORRECTION: {
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long offset;
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mutex_unlock(&rtc->ops_lock);
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if (param.index != 0)
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return -EINVAL;
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err = rtc_read_offset(rtc, &offset);
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mutex_lock(&rtc->ops_lock);
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if (err == 0)
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param.svalue = offset;
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break;
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}
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default:
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if (rtc->ops->param_get)
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err = rtc->ops->param_get(rtc->dev.parent, ¶m);
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else
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err = -EINVAL;
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}
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if (!err)
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if (copy_to_user(uarg, ¶m, sizeof(param)))
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err = -EFAULT;
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break;
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case RTC_PARAM_SET:
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if (copy_from_user(¶m, uarg, sizeof(param))) {
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mutex_unlock(&rtc->ops_lock);
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return -EFAULT;
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}
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switch(param.param) {
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case RTC_PARAM_FEATURES:
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err = -EINVAL;
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break;
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case RTC_PARAM_CORRECTION:
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mutex_unlock(&rtc->ops_lock);
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if (param.index != 0)
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return -EINVAL;
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return rtc_set_offset(rtc, param.svalue);
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default:
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if (rtc->ops->param_set)
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err = rtc->ops->param_set(rtc->dev.parent, ¶m);
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else
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err = -EINVAL;
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}
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break;
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default:
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/* Finally try the driver's ioctl interface */
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if (ops->ioctl) {
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err = ops->ioctl(rtc->dev.parent, cmd, arg);
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if (err == -ENOIOCTLCMD)
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err = -ENOTTY;
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} else {
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err = -ENOTTY;
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}
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break;
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}
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done:
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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#ifdef CONFIG_COMPAT
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#define RTC_IRQP_SET32 _IOW('p', 0x0c, __u32)
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#define RTC_IRQP_READ32 _IOR('p', 0x0b, __u32)
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#define RTC_EPOCH_SET32 _IOW('p', 0x0e, __u32)
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static long rtc_dev_compat_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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struct rtc_device *rtc = file->private_data;
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void __user *uarg = compat_ptr(arg);
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switch (cmd) {
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case RTC_IRQP_READ32:
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return put_user(rtc->irq_freq, (__u32 __user *)uarg);
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case RTC_IRQP_SET32:
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/* arg is a plain integer, not pointer */
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return rtc_dev_ioctl(file, RTC_IRQP_SET, arg);
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case RTC_EPOCH_SET32:
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/* arg is a plain integer, not pointer */
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return rtc_dev_ioctl(file, RTC_EPOCH_SET, arg);
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}
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return rtc_dev_ioctl(file, cmd, (unsigned long)uarg);
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}
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#endif
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static int rtc_dev_fasync(int fd, struct file *file, int on)
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{
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struct rtc_device *rtc = file->private_data;
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return fasync_helper(fd, file, on, &rtc->async_queue);
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}
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static int rtc_dev_release(struct inode *inode, struct file *file)
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{
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struct rtc_device *rtc = file->private_data;
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/* We shut down the repeating IRQs that userspace enabled,
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* since nothing is listening to them.
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* - Update (UIE) ... currently only managed through ioctls
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* - Periodic (PIE) ... also used through rtc_*() interface calls
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*
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* Leave the alarm alone; it may be set to trigger a system wakeup
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* later, or be used by kernel code, and is a one-shot event anyway.
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*/
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/* Keep ioctl until all drivers are converted */
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rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
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rtc_update_irq_enable(rtc, 0);
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rtc_irq_set_state(rtc, 0);
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clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
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return 0;
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}
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static const struct file_operations rtc_dev_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.read = rtc_dev_read,
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.poll = rtc_dev_poll,
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.unlocked_ioctl = rtc_dev_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = rtc_dev_compat_ioctl,
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#endif
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|
.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);
|
|
}
|