Linux-2.6.33.2/drivers/char/genrtc.c
/*
* Real Time Clock interface for
* - q40 and other m68k machines,
* - HP PARISC machines
* - PowerPC machines
* emulate some RTC irq capabilities in software
*
* Copyright (C) 1999 Richard Zidlicky
*
* based on Paul Gortmaker's rtc.c device and
* Sam Creasey Generic rtc driver
*
* This driver allows use of the real time clock (built into
* nearly all computers) from user space. It exports the /dev/rtc
* interface supporting various ioctl() and also the /proc/driver/rtc
* pseudo-file for status information.
*
* The ioctls can be used to set the interrupt behaviour where
* supported.
*
* The /dev/rtc interface will block on reads until an interrupt
* has been received. If a RTC interrupt has already happened,
* it will output an unsigned long and then block. The output value
* contains the interrupt status in the low byte and the number of
* interrupts since the last read in the remaining high bytes. The
* /dev/rtc interface can also be used with the select(2) call.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* 1.01 fix for 2.3.X rz@linux-m68k.org
* 1.02 merged with code from genrtc.c rz@linux-m68k.org
* 1.03 make it more portable zippel@linux-m68k.org
* 1.04 removed useless timer code rz@linux-m68k.org
* 1.05 portable RTC_UIE emulation rz@linux-m68k.org
* 1.06 set_rtc_time can return an error trini@kernel.crashing.org
* 1.07 ported to HP PARISC (hppa) Helge Deller <deller@gmx.de>
*/
#define RTC_VERSION "1.07"
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/smp_lock.h>
#include <linux/workqueue.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/rtc.h>
/*
* We sponge a minor off of the misc major. No need slurping
* up another valuable major dev number for this. If you add
* an ioctl, make sure you don't conflict with SPARC's RTC
* ioctls.
*/
static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait);
/*
* Bits in gen_rtc_status.
*/
#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
static unsigned char gen_rtc_status; /* bitmapped status byte. */
static unsigned long gen_rtc_irq_data; /* our output to the world */
/* months start at 0 now */
static unsigned char days_in_mo[] =
{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
static int irq_active;
#ifdef CONFIG_GEN_RTC_X
static struct work_struct genrtc_task;
static struct timer_list timer_task;
static unsigned int oldsecs;
static int lostint;
static unsigned long tt_exp;
static void gen_rtc_timer(unsigned long data);
static volatile int stask_active; /* schedule_work */
static volatile int ttask_active; /* timer_task */
static int stop_rtc_timers; /* don't requeue tasks */
static DEFINE_SPINLOCK(gen_rtc_lock);
static void gen_rtc_interrupt(unsigned long arg);
/*
* Routine to poll RTC seconds field for change as often as possible,
* after first RTC_UIE use timer to reduce polling
*/
static void genrtc_troutine(struct work_struct *work)
{
unsigned int tmp = get_rtc_ss();
if (stop_rtc_timers) {
stask_active = 0;
return;
}
if (oldsecs != tmp){
oldsecs = tmp;
timer_task.function = gen_rtc_timer;
timer_task.expires = jiffies + HZ - (HZ/10);
tt_exp=timer_task.expires;
ttask_active=1;
stask_active=0;
add_timer(&timer_task);
gen_rtc_interrupt(0);
} else if (schedule_work(&genrtc_task) == 0)
stask_active = 0;
}
static void gen_rtc_timer(unsigned long data)
{
lostint = get_rtc_ss() - oldsecs ;
if (lostint<0)
lostint = 60 - lostint;
if (time_after(jiffies, tt_exp))
printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n",
jiffies-tt_exp);
ttask_active=0;
stask_active=1;
if ((schedule_work(&genrtc_task) == 0))
stask_active = 0;
}
/*
* call gen_rtc_interrupt function to signal an RTC_UIE,
* arg is unused.
* Could be invoked either from a real interrupt handler or
* from some routine that periodically (eg 100HZ) monitors
* whether RTC_SECS changed
*/
static void gen_rtc_interrupt(unsigned long arg)
{
/* We store the status in the low byte and the number of
* interrupts received since the last read in the remainder
* of rtc_irq_data. */
gen_rtc_irq_data += 0x100;
gen_rtc_irq_data &= ~0xff;
gen_rtc_irq_data |= RTC_UIE;
if (lostint){
printk("genrtc: system delaying clock ticks?\n");
/* increment count so that userspace knows something is wrong */
gen_rtc_irq_data += ((lostint-1)<<8);
lostint = 0;
}
wake_up_interruptible(&gen_rtc_wait);
}
/*
* Now all the various file operations that we export.
*/
static ssize_t gen_rtc_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
unsigned long data;
ssize_t retval;
if (count != sizeof (unsigned int) && count != sizeof (unsigned long))
return -EINVAL;
if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data)
return -EAGAIN;
retval = wait_event_interruptible(gen_rtc_wait,
(data = xchg(&gen_rtc_irq_data, 0)));
if (retval)
goto out;
/* first test allows optimizer to nuke this case for 32-bit machines */
if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) {
unsigned int uidata = data;
retval = put_user(uidata, (unsigned int __user *)buf) ?:
sizeof(unsigned int);
}
else {
retval = put_user(data, (unsigned long __user *)buf) ?:
sizeof(unsigned long);
}
out:
return retval;
}
static unsigned int gen_rtc_poll(struct file *file,
struct poll_table_struct *wait)
{
poll_wait(file, &gen_rtc_wait, wait);
if (gen_rtc_irq_data != 0)
return POLLIN | POLLRDNORM;
return 0;
}
#endif
/*
* Used to disable/enable interrupts, only RTC_UIE supported
* We also clear out any old irq data after an ioctl() that
* meddles with the interrupt enable/disable bits.
*/
static inline void gen_clear_rtc_irq_bit(unsigned char bit)
{
#ifdef CONFIG_GEN_RTC_X
stop_rtc_timers = 1;
if (ttask_active){
del_timer_sync(&timer_task);
ttask_active = 0;
}
while (stask_active)
schedule();
spin_lock(&gen_rtc_lock);
irq_active = 0;
spin_unlock(&gen_rtc_lock);
#endif
}
static inline int gen_set_rtc_irq_bit(unsigned char bit)
{
#ifdef CONFIG_GEN_RTC_X
spin_lock(&gen_rtc_lock);
if ( !irq_active ) {
irq_active = 1;
stop_rtc_timers = 0;
lostint = 0;
INIT_WORK(&genrtc_task, genrtc_troutine);
oldsecs = get_rtc_ss();
init_timer(&timer_task);
stask_active = 1;
if (schedule_work(&genrtc_task) == 0){
stask_active = 0;
}
}
spin_unlock(&gen_rtc_lock);
gen_rtc_irq_data = 0;
return 0;
#else
return -EINVAL;
#endif
}
static int gen_rtc_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct rtc_time wtime;
struct rtc_pll_info pll;
void __user *argp = (void __user *)arg;
switch (cmd) {
case RTC_PLL_GET:
if (get_rtc_pll(&pll))
return -EINVAL;
else
return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0;
case RTC_PLL_SET:
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&pll, argp, sizeof(pll)))
return -EFAULT;
return set_rtc_pll(&pll);
case RTC_UIE_OFF: /* disable ints from RTC updates. */
gen_clear_rtc_irq_bit(RTC_UIE);
return 0;
case RTC_UIE_ON: /* enable ints for RTC updates. */
return gen_set_rtc_irq_bit(RTC_UIE);
case RTC_RD_TIME: /* Read the time/date from RTC */
/* this doesn't get week-day, who cares */
memset(&wtime, 0, sizeof(wtime));
get_rtc_time(&wtime);
return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0;
case RTC_SET_TIME: /* Set the RTC */
{
int year;
unsigned char leap_yr;
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&wtime, argp, sizeof(wtime)))
return -EFAULT;
year = wtime.tm_year + 1900;
leap_yr = ((!(year % 4) && (year % 100)) ||
!(year % 400));
if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1))
return -EINVAL;
if (wtime.tm_mday < 0 || wtime.tm_mday >
(days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr)))
return -EINVAL;
if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 ||
wtime.tm_min < 0 || wtime.tm_min >= 60 ||
wtime.tm_sec < 0 || wtime.tm_sec >= 60)
return -EINVAL;
return set_rtc_time(&wtime);
}
}
return -EINVAL;
}
/*
* We enforce only one user at a time here with the open/close.
* Also clear the previous interrupt data on an open, and clean
* up things on a close.
*/
static int gen_rtc_open(struct inode *inode, struct file *file)
{
lock_kernel();
if (gen_rtc_status & RTC_IS_OPEN) {
unlock_kernel();
return -EBUSY;
}
gen_rtc_status |= RTC_IS_OPEN;
gen_rtc_irq_data = 0;
irq_active = 0;
unlock_kernel();
return 0;
}
static int gen_rtc_release(struct inode *inode, struct file *file)
{
/*
* Turn off all interrupts once the device is no longer
* in use and clear the data.
*/
gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
gen_rtc_status &= ~RTC_IS_OPEN;
return 0;
}
#ifdef CONFIG_PROC_FS
/*
* Info exported via "/proc/driver/rtc".
*/
static int gen_rtc_proc_output(char *buf)
{
char *p;
struct rtc_time tm;
unsigned int flags;
struct rtc_pll_info pll;
p = buf;
flags = get_rtc_time(&tm);
p += sprintf(p,
"rtc_time\t: %02d:%02d:%02d\n"
"rtc_date\t: %04d-%02d-%02d\n"
"rtc_epoch\t: %04u\n",
tm.tm_hour, tm.tm_min, tm.tm_sec,
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900);
tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
p += sprintf(p, "alarm\t\t: ");
if (tm.tm_hour <= 24)
p += sprintf(p, "%02d:", tm.tm_hour);
else
p += sprintf(p, "**:");
if (tm.tm_min <= 59)
p += sprintf(p, "%02d:", tm.tm_min);
else
p += sprintf(p, "**:");
if (tm.tm_sec <= 59)
p += sprintf(p, "%02d\n", tm.tm_sec);
else
p += sprintf(p, "**\n");
p += sprintf(p,
"DST_enable\t: %s\n"
"BCD\t\t: %s\n"
"24hr\t\t: %s\n"
"square_wave\t: %s\n"
"alarm_IRQ\t: %s\n"
"update_IRQ\t: %s\n"
"periodic_IRQ\t: %s\n"
"periodic_freq\t: %ld\n"
"batt_status\t: %s\n",
(flags & RTC_DST_EN) ? "yes" : "no",
(flags & RTC_DM_BINARY) ? "no" : "yes",
(flags & RTC_24H) ? "yes" : "no",
(flags & RTC_SQWE) ? "yes" : "no",
(flags & RTC_AIE) ? "yes" : "no",
irq_active ? "yes" : "no",
(flags & RTC_PIE) ? "yes" : "no",
0L /* freq */,
(flags & RTC_BATT_BAD) ? "bad" : "okay");
if (!get_rtc_pll(&pll))
p += sprintf(p,
"PLL adjustment\t: %d\n"
"PLL max +ve adjustment\t: %d\n"
"PLL max -ve adjustment\t: %d\n"
"PLL +ve adjustment factor\t: %d\n"
"PLL -ve adjustment factor\t: %d\n"
"PLL frequency\t: %ld\n",
pll.pll_value,
pll.pll_max,
pll.pll_min,
pll.pll_posmult,
pll.pll_negmult,
pll.pll_clock);
return p - buf;
}
static int gen_rtc_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = gen_rtc_proc_output (page);
if (len <= off+count) *eof = 1;
*start = page + off;
len -= off;
if (len>count) len = count;
if (len<0) len = 0;
return len;
}
static int __init gen_rtc_proc_init(void)
{
struct proc_dir_entry *r;
r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL);
if (!r)
return -ENOMEM;
return 0;
}
#else
static inline int gen_rtc_proc_init(void) { return 0; }
#endif /* CONFIG_PROC_FS */
/*
* The various file operations we support.
*/
static const struct file_operations gen_rtc_fops = {
.owner = THIS_MODULE,
#ifdef CONFIG_GEN_RTC_X
.read = gen_rtc_read,
.poll = gen_rtc_poll,
#endif
.ioctl = gen_rtc_ioctl,
.open = gen_rtc_open,
.release = gen_rtc_release,
};
static struct miscdevice rtc_gen_dev =
{
.minor = RTC_MINOR,
.name = "rtc",
.fops = &gen_rtc_fops,
};
static int __init rtc_generic_init(void)
{
int retval;
printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION);
retval = misc_register(&rtc_gen_dev);
if (retval < 0)
return retval;
retval = gen_rtc_proc_init();
if (retval) {
misc_deregister(&rtc_gen_dev);
return retval;
}
return 0;
}
static void __exit rtc_generic_exit(void)
{
remove_proc_entry ("driver/rtc", NULL);
misc_deregister(&rtc_gen_dev);
}
module_init(rtc_generic_init);
module_exit(rtc_generic_exit);
MODULE_AUTHOR("Richard Zidlicky");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(RTC_MINOR);