// SPDX-License-Identifier: GPL-2.0/* * RTC subsystem, dev interface * * Copyright (C) 2005 Tower Technologies * Author: Alessandro Zummo <a.zummo@towertech.it> * * based on arch/arm/common/rtctime.c */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/compat.h>#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_trtc_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) {		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;	struct rtc_param param;	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:	case RTC_PARAM_SET:		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; 	case RTC_PARAM_GET:		if (copy_from_user(&param, uarg, sizeof(param))) {			mutex_unlock(&rtc->ops_lock);			return -EFAULT;		} 		switch(param.param) {		case RTC_PARAM_FEATURES:			if (param.index != 0)				err = -EINVAL;			param.uvalue = rtc->features[0];			break; 		case RTC_PARAM_CORRECTION: {			long offset;			mutex_unlock(&rtc->ops_lock);			if (param.index != 0)				return -EINVAL;			err = rtc_read_offset(rtc, &offset);			mutex_lock(&rtc->ops_lock);			if (err == 0)				param.svalue = offset;			break;		}		default:			if (rtc->ops->param_get)				err = rtc->ops->param_get(rtc->dev.parent, &param);			else				err = -EINVAL;		} 		if (!err)			if (copy_to_user(uarg, &param, sizeof(param)))				err = -EFAULT; 		break; 	case RTC_PARAM_SET:		if (copy_from_user(&param, uarg, sizeof(param))) {			mutex_unlock(&rtc->ops_lock);			return -EFAULT;		} 		switch(param.param) {		case RTC_PARAM_FEATURES:			err = -EINVAL;			break; 		case RTC_PARAM_CORRECTION:			mutex_unlock(&rtc->ops_lock);			if (param.index != 0)				return -EINVAL;			return rtc_set_offset(rtc, param.svalue); 		default:			if (rtc->ops->param_set)				err = rtc->ops->param_set(rtc->dev.parent, &param);			else				err = -EINVAL;		} 		break; 	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;} #ifdef CONFIG_COMPAT#define RTC_IRQP_SET32		_IOW('p', 0x0c, __u32)#define RTC_IRQP_READ32		_IOR('p', 0x0b, __u32)#define RTC_EPOCH_SET32		_IOW('p', 0x0e, __u32) static long rtc_dev_compat_ioctl(struct file *file,				 unsigned int cmd, unsigned long arg){	struct rtc_device *rtc = file->private_data;	void __user *uarg = compat_ptr(arg); 	switch (cmd) {	case RTC_IRQP_READ32:		return put_user(rtc->irq_freq, (__u32 __user *)uarg); 	case RTC_IRQP_SET32:		/* arg is a plain integer, not pointer */		return rtc_dev_ioctl(file, RTC_IRQP_SET, arg); 	case RTC_EPOCH_SET32:		/* arg is a plain integer, not pointer */		return rtc_dev_ioctl(file, RTC_EPOCH_SET, arg);	} 	return rtc_dev_ioctl(file, cmd, (unsigned long)uarg);}#endif 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);}

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