/* * 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.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) { int err; struct rtc_device *rtc = container_of(inode->i_cdev, struct rtc_device, char_dev); const struct rtc_class_ops *ops = rtc->ops; if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) return -EBUSY; file->private_data = rtc; err = ops->open ? ops->open(rtc->dev.parent) : 0; if (err == 0) { spin_lock_irq(&rtc->irq_lock); rtc->irq_data = 0; spin_unlock_irq(&rtc->irq_lock); return 0; } /* something has gone wrong */ clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); return err; } #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(unsigned long data) { struct rtc_device *rtc = (struct rtc_device *)data; 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 unsigned int 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) ? (POLLIN | POLLRDNORM) : 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, NULL, 1); break; case RTC_PIE_OFF: err = rtc_irq_set_state(rtc, NULL, 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, NULL, 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, NULL, 0); if (rtc->ops->release) rtc->ops->release(rtc->dev.parent); 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, "%s: too many RTC devices\n", rtc->name); 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); setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc); #endif cdev_init(&rtc->char_dev, &rtc_dev_fops); rtc->char_dev.owner = rtc->owner; rtc->char_dev.kobj.parent = &rtc->dev.kobj; } void rtc_dev_add_device(struct rtc_device *rtc) { if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1)) dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n", rtc->name, MAJOR(rtc_devt), rtc->id); else dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name, MAJOR(rtc_devt), rtc->id); } void rtc_dev_del_device(struct rtc_device *rtc) { if (rtc->dev.devt) cdev_del(&rtc->char_dev); } 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); }