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linux/drivers/sbus/char/rtc.c
Arjan van de Ven 00977a59b9 [PATCH] mark struct file_operations const 6 
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.

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>
2007-02-12 09:48:45 -08:00

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/* $Id: rtc.c,v 1.28 2001/10/08 22:19:51 davem Exp $
*
* Linux/SPARC Real Time Clock Driver
* Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
*
* This is a little driver that lets a user-level program access
* the SPARC Mostek real time clock chip. It is no use unless you
* use the modified clock utility.
*
* Get the modified clock utility from:
* ftp://vger.kernel.org/pub/linux/Sparc/userland/clock.c
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <asm/io.h>
#include <asm/mostek.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/rtc.h>
static int rtc_busy = 0;
/* This is the structure layout used by drivers/char/rtc.c, we
* support that driver's ioctls so that things are less messy in
* userspace.
*/
struct rtc_time_generic {
int tm_sec;
int tm_min;
int tm_hour;
int tm_mday;
int tm_mon;
int tm_year;
int tm_wday;
int tm_yday;
int tm_isdst;
};
#define RTC_AIE_ON _IO('p', 0x01) /* Alarm int. enable on */
#define RTC_AIE_OFF _IO('p', 0x02) /* ... off */
#define RTC_UIE_ON _IO('p', 0x03) /* Update int. enable on */
#define RTC_UIE_OFF _IO('p', 0x04) /* ... off */
#define RTC_PIE_ON _IO('p', 0x05) /* Periodic int. enable on */
#define RTC_PIE_OFF _IO('p', 0x06) /* ... off */
#define RTC_WIE_ON _IO('p', 0x0f) /* Watchdog int. enable on */
#define RTC_WIE_OFF _IO('p', 0x10) /* ... off */
#define RTC_RD_TIME _IOR('p', 0x09, struct rtc_time_generic) /* Read RTC time */
#define RTC_SET_TIME _IOW('p', 0x0a, struct rtc_time_generic) /* Set RTC time */
#define RTC_ALM_SET _IOW('p', 0x07, struct rtc_time) /* Set alarm time */
#define RTC_ALM_READ _IOR('p', 0x08, struct rtc_time) /* Read alarm time */
#define RTC_IRQP_READ _IOR('p', 0x0b, unsigned long) /* Read IRQ rate */
#define RTC_IRQP_SET _IOW('p', 0x0c, unsigned long) /* Set IRQ rate */
#define RTC_EPOCH_READ _IOR('p', 0x0d, unsigned long) /* Read epoch */
#define RTC_EPOCH_SET _IOW('p', 0x0e, unsigned long) /* Set epoch */
#define RTC_WKALM_SET _IOW('p', 0x0f, struct rtc_wkalrm)/* Set wakeup alarm*/
#define RTC_WKALM_RD _IOR('p', 0x10, struct rtc_wkalrm)/* Get wakeup alarm*/
#define RTC_PLL_GET _IOR('p', 0x11, struct rtc_pll_info) /* Get PLL correction */
#define RTC_PLL_SET _IOW('p', 0x12, struct rtc_pll_info) /* Set PLL correction */
/* Retrieve the current date and time from the real time clock. */
static void get_rtc_time(struct rtc_time *t)
{
void __iomem *regs = mstk48t02_regs;
u8 tmp;
spin_lock_irq(&mostek_lock);
tmp = mostek_read(regs + MOSTEK_CREG);
tmp |= MSTK_CREG_READ;
mostek_write(regs + MOSTEK_CREG, tmp);
t->sec = MSTK_REG_SEC(regs);
t->min = MSTK_REG_MIN(regs);
t->hour = MSTK_REG_HOUR(regs);
t->dow = MSTK_REG_DOW(regs);
t->dom = MSTK_REG_DOM(regs);
t->month = MSTK_REG_MONTH(regs);
t->year = MSTK_CVT_YEAR( MSTK_REG_YEAR(regs) );
tmp = mostek_read(regs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_READ;
mostek_write(regs + MOSTEK_CREG, tmp);
spin_unlock_irq(&mostek_lock);
}
/* Set the current date and time inthe real time clock. */
void set_rtc_time(struct rtc_time *t)
{
void __iomem *regs = mstk48t02_regs;
u8 tmp;
spin_lock_irq(&mostek_lock);
tmp = mostek_read(regs + MOSTEK_CREG);
tmp |= MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
MSTK_SET_REG_SEC(regs,t->sec);
MSTK_SET_REG_MIN(regs,t->min);
MSTK_SET_REG_HOUR(regs,t->hour);
MSTK_SET_REG_DOW(regs,t->dow);
MSTK_SET_REG_DOM(regs,t->dom);
MSTK_SET_REG_MONTH(regs,t->month);
MSTK_SET_REG_YEAR(regs,t->year - MSTK_YEAR_ZERO);
tmp = mostek_read(regs + MOSTEK_CREG);
tmp &= ~MSTK_CREG_WRITE;
mostek_write(regs + MOSTEK_CREG, tmp);
spin_unlock_irq(&mostek_lock);
}
static int put_rtc_time_generic(void __user *argp, struct rtc_time *tm)
{
struct rtc_time_generic __user *utm = argp;
if (__put_user(tm->sec, &utm->tm_sec) ||
__put_user(tm->min, &utm->tm_min) ||
__put_user(tm->hour, &utm->tm_hour) ||
__put_user(tm->dom, &utm->tm_mday) ||
__put_user(tm->month, &utm->tm_mon) ||
__put_user(tm->year, &utm->tm_year) ||
__put_user(tm->dow, &utm->tm_wday) ||
__put_user(0, &utm->tm_yday) ||
__put_user(0, &utm->tm_isdst))
return -EFAULT;
return 0;
}
static int get_rtc_time_generic(struct rtc_time *tm, void __user *argp)
{
struct rtc_time_generic __user *utm = argp;
if (__get_user(tm->sec, &utm->tm_sec) ||
__get_user(tm->min, &utm->tm_min) ||
__get_user(tm->hour, &utm->tm_hour) ||
__get_user(tm->dom, &utm->tm_mday) ||
__get_user(tm->month, &utm->tm_mon) ||
__get_user(tm->year, &utm->tm_year) ||
__get_user(tm->dow, &utm->tm_wday))
return -EFAULT;
return 0;
}
static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
struct rtc_time rtc_tm;
void __user *argp = (void __user *)arg;
switch (cmd) {
/* No interrupt support, return an error
* compatible with drivers/char/rtc.c
*/
case RTC_AIE_OFF:
case RTC_AIE_ON:
case RTC_PIE_OFF:
case RTC_PIE_ON:
case RTC_UIE_OFF:
case RTC_UIE_ON:
case RTC_IRQP_READ:
case RTC_IRQP_SET:
case RTC_EPOCH_SET:
case RTC_EPOCH_READ:
return -EINVAL;
case RTCGET:
case RTC_RD_TIME:
memset(&rtc_tm, 0, sizeof(struct rtc_time));
get_rtc_time(&rtc_tm);
if (cmd == RTCGET) {
if (copy_to_user(argp, &rtc_tm,
sizeof(struct rtc_time)))
return -EFAULT;
} else if (put_rtc_time_generic(argp, &rtc_tm))
return -EFAULT;
return 0;
case RTCSET:
case RTC_SET_TIME:
if (!capable(CAP_SYS_TIME))
return -EPERM;
if (cmd == RTCSET) {
if (copy_from_user(&rtc_tm, argp,
sizeof(struct rtc_time)))
return -EFAULT;
} else if (get_rtc_time_generic(&rtc_tm, argp))
return -EFAULT;
set_rtc_time(&rtc_tm);
return 0;
default:
return -EINVAL;
}
}
static int rtc_open(struct inode *inode, struct file *file)
{
int ret;
spin_lock_irq(&mostek_lock);
if (rtc_busy) {
ret = -EBUSY;
} else {
rtc_busy = 1;
ret = 0;
}
spin_unlock_irq(&mostek_lock);
return ret;
}
static int rtc_release(struct inode *inode, struct file *file)
{
rtc_busy = 0;
return 0;
}
static const struct file_operations rtc_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.ioctl = rtc_ioctl,
.open = rtc_open,
.release = rtc_release,
};
static struct miscdevice rtc_dev = { RTC_MINOR, "rtc", &rtc_fops };
static int __init rtc_sun_init(void)
{
int error;
/* It is possible we are being driven by some other RTC chip
* and thus another RTC driver is handling things.
*/
if (!mstk48t02_regs)
return -ENODEV;
error = misc_register(&rtc_dev);
if (error) {
printk(KERN_ERR "rtc: unable to get misc minor for Mostek\n");
return error;
}
printk("rtc_sun_init: Registered Mostek RTC driver.\n");
return 0;
}
static void __exit rtc_sun_cleanup(void)
{
misc_deregister(&rtc_dev);
}
module_init(rtc_sun_init);
module_exit(rtc_sun_cleanup);
MODULE_LICENSE("GPL");
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