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![Arjan van de Ven](/assets/img/avatar_default.png)
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. [akpm@osdl.org: sparc64 fix] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
436 lines
8.9 KiB
C
436 lines
8.9 KiB
C
/*
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* linux/arch/arm/common/rtctime.c
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*
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* Copyright (C) 2003 Deep Blue Solutions Ltd.
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* Based on sa1100-rtc.c, Nils Faerber, CIH, Nicolas Pitre.
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* Based on rtc.c by Paul Gortmaker
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/time.h>
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#include <linux/rtc.h>
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#include <linux/poll.h>
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#include <linux/proc_fs.h>
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#include <linux/miscdevice.h>
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#include <linux/spinlock.h>
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#include <linux/capability.h>
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/rtc.h>
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#include <asm/rtc.h>
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#include <asm/semaphore.h>
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static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
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static struct fasync_struct *rtc_async_queue;
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/*
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* rtc_lock protects rtc_irq_data
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*/
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static DEFINE_SPINLOCK(rtc_lock);
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static unsigned long rtc_irq_data;
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/*
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* rtc_sem protects rtc_inuse and rtc_ops
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*/
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static DEFINE_MUTEX(rtc_mutex);
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static unsigned long rtc_inuse;
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static struct rtc_ops *rtc_ops;
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#define rtc_epoch 1900UL
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/*
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* Calculate the next alarm time given the requested alarm time mask
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* and the current time.
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*/
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void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm)
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{
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unsigned long next_time;
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unsigned long now_time;
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next->tm_year = now->tm_year;
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next->tm_mon = now->tm_mon;
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next->tm_mday = now->tm_mday;
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next->tm_hour = alrm->tm_hour;
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next->tm_min = alrm->tm_min;
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next->tm_sec = alrm->tm_sec;
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rtc_tm_to_time(now, &now_time);
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rtc_tm_to_time(next, &next_time);
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if (next_time < now_time) {
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/* Advance one day */
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next_time += 60 * 60 * 24;
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rtc_time_to_tm(next_time, next);
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}
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}
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EXPORT_SYMBOL(rtc_next_alarm_time);
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static inline int rtc_arm_read_time(struct rtc_ops *ops, struct rtc_time *tm)
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{
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memset(tm, 0, sizeof(struct rtc_time));
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return ops->read_time(tm);
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}
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static inline int rtc_arm_set_time(struct rtc_ops *ops, struct rtc_time *tm)
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{
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int ret;
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ret = rtc_valid_tm(tm);
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if (ret == 0)
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ret = ops->set_time(tm);
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return ret;
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}
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static inline int rtc_arm_read_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
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{
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int ret = -EINVAL;
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if (ops->read_alarm) {
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memset(alrm, 0, sizeof(struct rtc_wkalrm));
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ret = ops->read_alarm(alrm);
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}
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return ret;
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}
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static inline int rtc_arm_set_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
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{
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int ret = -EINVAL;
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if (ops->set_alarm)
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ret = ops->set_alarm(alrm);
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return ret;
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}
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void rtc_update(unsigned long num, unsigned long events)
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{
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spin_lock(&rtc_lock);
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rtc_irq_data = (rtc_irq_data + (num << 8)) | events;
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spin_unlock(&rtc_lock);
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wake_up_interruptible(&rtc_wait);
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kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
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}
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EXPORT_SYMBOL(rtc_update);
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static ssize_t
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rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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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 long))
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return -EINVAL;
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add_wait_queue(&rtc_wait, &wait);
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do {
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__set_current_state(TASK_INTERRUPTIBLE);
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spin_lock_irq(&rtc_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_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_wait, &wait);
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if (ret == 0) {
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ret = put_user(data, (unsigned long __user *)buf);
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if (ret == 0)
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ret = sizeof(unsigned long);
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}
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return ret;
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}
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static unsigned int rtc_poll(struct file *file, poll_table *wait)
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{
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unsigned long data;
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poll_wait(file, &rtc_wait, wait);
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spin_lock_irq(&rtc_lock);
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data = rtc_irq_data;
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spin_unlock_irq(&rtc_lock);
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return data != 0 ? POLLIN | POLLRDNORM : 0;
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}
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static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct rtc_ops *ops = file->private_data;
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struct rtc_time tm;
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struct rtc_wkalrm alrm;
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void __user *uarg = (void __user *)arg;
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int ret = -EINVAL;
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switch (cmd) {
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case RTC_ALM_READ:
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ret = rtc_arm_read_alarm(ops, &alrm);
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if (ret)
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break;
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ret = copy_to_user(uarg, &alrm.time, sizeof(tm));
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if (ret)
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ret = -EFAULT;
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break;
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case RTC_ALM_SET:
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ret = copy_from_user(&alrm.time, uarg, sizeof(tm));
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if (ret) {
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ret = -EFAULT;
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break;
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}
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alrm.enabled = 0;
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alrm.pending = 0;
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alrm.time.tm_mday = -1;
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alrm.time.tm_mon = -1;
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alrm.time.tm_year = -1;
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alrm.time.tm_wday = -1;
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alrm.time.tm_yday = -1;
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alrm.time.tm_isdst = -1;
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ret = rtc_arm_set_alarm(ops, &alrm);
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break;
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case RTC_RD_TIME:
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ret = rtc_arm_read_time(ops, &tm);
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if (ret)
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break;
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ret = copy_to_user(uarg, &tm, sizeof(tm));
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if (ret)
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ret = -EFAULT;
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break;
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case RTC_SET_TIME:
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if (!capable(CAP_SYS_TIME)) {
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ret = -EACCES;
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break;
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}
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ret = copy_from_user(&tm, uarg, sizeof(tm));
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if (ret) {
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ret = -EFAULT;
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break;
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}
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ret = rtc_arm_set_time(ops, &tm);
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break;
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case RTC_EPOCH_SET:
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#ifndef rtc_epoch
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/*
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* There were no RTC clocks before 1900.
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*/
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if (arg < 1900) {
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ret = -EINVAL;
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break;
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}
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if (!capable(CAP_SYS_TIME)) {
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ret = -EACCES;
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break;
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}
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rtc_epoch = arg;
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ret = 0;
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#endif
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break;
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case RTC_EPOCH_READ:
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ret = put_user(rtc_epoch, (unsigned long __user *)uarg);
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break;
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case RTC_WKALM_SET:
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ret = copy_from_user(&alrm, uarg, sizeof(alrm));
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if (ret) {
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ret = -EFAULT;
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break;
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}
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ret = rtc_arm_set_alarm(ops, &alrm);
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break;
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case RTC_WKALM_RD:
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ret = rtc_arm_read_alarm(ops, &alrm);
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if (ret)
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break;
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ret = copy_to_user(uarg, &alrm, sizeof(alrm));
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if (ret)
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ret = -EFAULT;
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break;
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default:
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if (ops->ioctl)
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ret = ops->ioctl(cmd, arg);
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break;
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}
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return ret;
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}
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static int rtc_open(struct inode *inode, struct file *file)
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{
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int ret;
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mutex_lock(&rtc_mutex);
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if (rtc_inuse) {
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ret = -EBUSY;
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} else if (!rtc_ops || !try_module_get(rtc_ops->owner)) {
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ret = -ENODEV;
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} else {
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file->private_data = rtc_ops;
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ret = rtc_ops->open ? rtc_ops->open() : 0;
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if (ret == 0) {
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spin_lock_irq(&rtc_lock);
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rtc_irq_data = 0;
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spin_unlock_irq(&rtc_lock);
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rtc_inuse = 1;
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}
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}
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mutex_unlock(&rtc_mutex);
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return ret;
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}
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static int rtc_release(struct inode *inode, struct file *file)
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{
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struct rtc_ops *ops = file->private_data;
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if (ops->release)
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ops->release();
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spin_lock_irq(&rtc_lock);
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rtc_irq_data = 0;
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spin_unlock_irq(&rtc_lock);
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module_put(rtc_ops->owner);
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rtc_inuse = 0;
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return 0;
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}
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static int rtc_fasync(int fd, struct file *file, int on)
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{
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return fasync_helper(fd, file, on, &rtc_async_queue);
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}
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static const struct file_operations rtc_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.read = rtc_read,
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.poll = rtc_poll,
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.ioctl = rtc_ioctl,
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.open = rtc_open,
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.release = rtc_release,
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.fasync = rtc_fasync,
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};
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static struct miscdevice rtc_miscdev = {
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.minor = RTC_MINOR,
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.name = "rtc",
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.fops = &rtc_fops,
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};
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static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data)
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{
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struct rtc_ops *ops = data;
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struct rtc_wkalrm alrm;
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struct rtc_time tm;
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char *p = page;
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if (rtc_arm_read_time(ops, &tm) == 0) {
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p += sprintf(p,
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"rtc_time\t: %02d:%02d:%02d\n"
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"rtc_date\t: %04d-%02d-%02d\n"
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"rtc_epoch\t: %04lu\n",
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tm.tm_hour, tm.tm_min, tm.tm_sec,
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tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
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rtc_epoch);
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}
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if (rtc_arm_read_alarm(ops, &alrm) == 0) {
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p += sprintf(p, "alrm_time\t: ");
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if ((unsigned int)alrm.time.tm_hour <= 24)
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p += sprintf(p, "%02d:", alrm.time.tm_hour);
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else
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p += sprintf(p, "**:");
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if ((unsigned int)alrm.time.tm_min <= 59)
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p += sprintf(p, "%02d:", alrm.time.tm_min);
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else
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p += sprintf(p, "**:");
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if ((unsigned int)alrm.time.tm_sec <= 59)
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p += sprintf(p, "%02d\n", alrm.time.tm_sec);
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else
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p += sprintf(p, "**\n");
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p += sprintf(p, "alrm_date\t: ");
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if ((unsigned int)alrm.time.tm_year <= 200)
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p += sprintf(p, "%04d-", alrm.time.tm_year + 1900);
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else
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p += sprintf(p, "****-");
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if ((unsigned int)alrm.time.tm_mon <= 11)
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p += sprintf(p, "%02d-", alrm.time.tm_mon + 1);
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else
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p += sprintf(p, "**-");
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if ((unsigned int)alrm.time.tm_mday <= 31)
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p += sprintf(p, "%02d\n", alrm.time.tm_mday);
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else
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p += sprintf(p, "**\n");
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p += sprintf(p, "alrm_wakeup\t: %s\n",
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alrm.enabled ? "yes" : "no");
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p += sprintf(p, "alrm_pending\t: %s\n",
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alrm.pending ? "yes" : "no");
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}
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if (ops->proc)
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p += ops->proc(p);
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return p - page;
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}
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int register_rtc(struct rtc_ops *ops)
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{
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int ret = -EBUSY;
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mutex_lock(&rtc_mutex);
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if (rtc_ops == NULL) {
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rtc_ops = ops;
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ret = misc_register(&rtc_miscdev);
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if (ret == 0)
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create_proc_read_entry("driver/rtc", 0, NULL,
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rtc_read_proc, ops);
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}
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mutex_unlock(&rtc_mutex);
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return ret;
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}
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EXPORT_SYMBOL(register_rtc);
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void unregister_rtc(struct rtc_ops *rtc)
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{
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mutex_lock(&rtc_mutex);
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if (rtc == rtc_ops) {
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remove_proc_entry("driver/rtc", NULL);
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misc_deregister(&rtc_miscdev);
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rtc_ops = NULL;
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}
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mutex_unlock(&rtc_mutex);
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}
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EXPORT_SYMBOL(unregister_rtc);
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