/* * 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. */ #include <linux/module.h> #include <linux/rtc.h> static struct class *rtc_dev_class; 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; /* We keep the lock as long as the device is in use * and return immediately if busy */ if (!(mutex_trylock(&rtc->char_lock))) return -EBUSY; file->private_data = &rtc->class_dev; err = ops->open ? ops->open(rtc->class_dev.dev) : 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, release the lock */ mutex_unlock(&rtc->char_lock); 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->class_dev, &tm); local_irq_disable(); spin_lock(&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(&rtc->irq_lock); if (num) rtc_update_irq(&rtc->class_dev, num, RTC_UF | RTC_IRQF); local_irq_enable(); } 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 void clear_uie(struct rtc_device *rtc) { spin_lock_irq(&rtc->irq_lock); if (rtc->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->irq_active = 0; } spin_unlock_irq(&rtc->irq_lock); } static int set_uie(struct rtc_device *rtc) { struct rtc_time tm; int err; err = rtc_read_time(&rtc->class_dev, &tm); if (err) return err; spin_lock_irq(&rtc->irq_lock); if (!rtc->irq_active) { rtc->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; } #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 = to_rtc_device(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->class_dev.dev, 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 = to_rtc_device(file->private_data); unsigned long data; poll_wait(file, &rtc->irq_queue, wait); data = rtc->irq_data; return (data != 0) ? (POLLIN | POLLRDNORM) : 0; } static int rtc_dev_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int err = 0; struct class_device *class_dev = file->private_data; struct rtc_device *rtc = to_rtc_device(class_dev); const struct rtc_class_ops *ops = rtc->ops; struct rtc_time tm; struct rtc_wkalrm alarm; void __user *uarg = (void __user *) arg; /* 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)) return -EACCES; break; case RTC_IRQP_SET: if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE)) return -EACCES; break; case RTC_PIE_ON: if (!capable(CAP_SYS_RESOURCE)) return -EACCES; break; } /* avoid conflicting IRQ users */ if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) { spin_lock_irq(&rtc->irq_task_lock); if (rtc->irq_task) err = -EBUSY; spin_unlock_irq(&rtc->irq_task_lock); if (err < 0) return err; } /* try the driver's ioctl interface */ if (ops->ioctl) { err = ops->ioctl(class_dev->dev, cmd, arg); if (err != -ENOIOCTLCMD) return err; } /* if the driver does not provide the ioctl interface * or if that particular ioctl was not implemented * (-ENOIOCTLCMD), we will try to emulate here. */ switch (cmd) { case RTC_ALM_READ: err = rtc_read_alarm(class_dev, &alarm); if (err < 0) return err; if (copy_to_user(uarg, &alarm.time, sizeof(tm))) return -EFAULT; break; case RTC_ALM_SET: if (copy_from_user(&alarm.time, uarg, sizeof(tm))) return -EFAULT; alarm.enabled = 0; alarm.pending = 0; alarm.time.tm_mday = -1; alarm.time.tm_mon = -1; alarm.time.tm_year = -1; alarm.time.tm_wday = -1; alarm.time.tm_yday = -1; alarm.time.tm_isdst = -1; err = rtc_set_alarm(class_dev, &alarm); break; case RTC_RD_TIME: err = rtc_read_time(class_dev, &tm); if (err < 0) return err; if (copy_to_user(uarg, &tm, sizeof(tm))) return -EFAULT; break; case RTC_SET_TIME: if (copy_from_user(&tm, uarg, sizeof(tm))) return -EFAULT; err = rtc_set_time(class_dev, &tm); break; case RTC_IRQP_READ: if (ops->irq_set_freq) err = put_user(rtc->irq_freq, (unsigned long __user *)uarg); break; case RTC_IRQP_SET: if (ops->irq_set_freq) err = rtc_irq_set_freq(class_dev, rtc->irq_task, arg); break; #if 0 case RTC_EPOCH_SET: #ifndef rtc_epoch /* * There were no RTC clocks before 1900. */ if (arg < 1900) { err = -EINVAL; break; } rtc_epoch = arg; err = 0; #endif break; case RTC_EPOCH_READ: err = put_user(rtc_epoch, (unsigned long __user *)uarg); break; #endif case RTC_WKALM_SET: if (copy_from_user(&alarm, uarg, sizeof(alarm))) return -EFAULT; err = rtc_set_alarm(class_dev, &alarm); break; case RTC_WKALM_RD: err = rtc_read_alarm(class_dev, &alarm); if (err < 0) return err; if (copy_to_user(uarg, &alarm, sizeof(alarm))) return -EFAULT; break; #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL case RTC_UIE_OFF: clear_uie(rtc); return 0; case RTC_UIE_ON: return set_uie(rtc); #endif default: err = -ENOTTY; break; } return err; } static int rtc_dev_release(struct inode *inode, struct file *file) { struct rtc_device *rtc = to_rtc_device(file->private_data); #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL clear_uie(rtc); #endif if (rtc->ops->release) rtc->ops->release(rtc->class_dev.dev); mutex_unlock(&rtc->char_lock); return 0; } static int rtc_dev_fasync(int fd, struct file *file, int on) { struct rtc_device *rtc = to_rtc_device(file->private_data); return fasync_helper(fd, file, on, &rtc->async_queue); } static const struct file_operations rtc_dev_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .read = rtc_dev_read, .poll = rtc_dev_poll, .ioctl = rtc_dev_ioctl, .open = rtc_dev_open, .release = rtc_dev_release, .fasync = rtc_dev_fasync, }; /* insertion/removal hooks */ static int rtc_dev_add_device(struct class_device *class_dev, struct class_interface *class_intf) { int err = 0; struct rtc_device *rtc = to_rtc_device(class_dev); if (rtc->id >= RTC_DEV_MAX) { dev_err(class_dev->dev, "too many RTCs\n"); return -EINVAL; } mutex_init(&rtc->char_lock); spin_lock_init(&rtc->irq_lock); init_waitqueue_head(&rtc->irq_queue); #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; if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) { dev_err(class_dev->dev, "failed to add char device %d:%d\n", MAJOR(rtc_devt), rtc->id); return -ENODEV; } rtc->rtc_dev = class_device_create(rtc_dev_class, NULL, MKDEV(MAJOR(rtc_devt), rtc->id), class_dev->dev, "rtc%d", rtc->id); if (IS_ERR(rtc->rtc_dev)) { dev_err(class_dev->dev, "cannot create rtc_dev device\n"); err = PTR_ERR(rtc->rtc_dev); goto err_cdev_del; } dev_dbg(class_dev->dev, "rtc intf: dev (%d:%d)\n", MAJOR(rtc->rtc_dev->devt), MINOR(rtc->rtc_dev->devt)); return 0; err_cdev_del: cdev_del(&rtc->char_dev); return err; } static void rtc_dev_remove_device(struct class_device *class_dev, struct class_interface *class_intf) { struct rtc_device *rtc = to_rtc_device(class_dev); if (rtc->rtc_dev) { dev_dbg(class_dev->dev, "removing char %d:%d\n", MAJOR(rtc->rtc_dev->devt), MINOR(rtc->rtc_dev->devt)); class_device_unregister(rtc->rtc_dev); cdev_del(&rtc->char_dev); } } /* interface registration */ static struct class_interface rtc_dev_interface = { .add = &rtc_dev_add_device, .remove = &rtc_dev_remove_device, }; static int __init rtc_dev_init(void) { int err; rtc_dev_class = class_create(THIS_MODULE, "rtc-dev"); if (IS_ERR(rtc_dev_class)) return PTR_ERR(rtc_dev_class); err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc"); if (err < 0) { printk(KERN_ERR "%s: failed to allocate char dev region\n", __FILE__); goto err_destroy_class; } err = rtc_interface_register(&rtc_dev_interface); if (err < 0) { printk(KERN_ERR "%s: failed to register the interface\n", __FILE__); goto err_unregister_chrdev; } return 0; err_unregister_chrdev: unregister_chrdev_region(rtc_devt, RTC_DEV_MAX); err_destroy_class: class_destroy(rtc_dev_class); return err; } static void __exit rtc_dev_exit(void) { class_interface_unregister(&rtc_dev_interface); class_destroy(rtc_dev_class); unregister_chrdev_region(rtc_devt, RTC_DEV_MAX); } subsys_initcall(rtc_dev_init); module_exit(rtc_dev_exit); MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); MODULE_DESCRIPTION("RTC class dev interface"); MODULE_LICENSE("GPL");