/*
* Real Time Clock interface for PPC64.
*
* Based on rtc.c by Paul Gortmaker
*
* This driver allows use of the real time clock
* from user space. It exports the /dev/rtc
* interface supporting various ioctl() and also the
* /proc/driver/rtc pseudo-file for status information.
*
* Interface does not support RTC interrupts nor an alarm.
*
* 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.
*
* 1.0 Mike Corrigan: IBM iSeries rtc support
* 1.1 Dave Engebretsen: IBM pSeries rtc support
*/
#define RTC_VERSION "1.1"
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/bcd.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/time.h>
#include <asm/rtas.h>
#include <asm/machdep.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 ssize_t rtc_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos);
static int rtc_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
static int rtc_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data);
/*
* If this driver ever becomes modularised, it will be really nice
* to make the epoch retain its value across module reload...
*/
static unsigned long epoch = 1900; /* year corresponding to 0x00 */
static const unsigned char days_in_mo[] =
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
/*
* Now all the various file operations that we export.
*/
static ssize_t rtc_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
return -EIO;
}
static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
struct rtc_time wtime;
switch (cmd) {
case RTC_RD_TIME: /* Read the time/date from RTC */
{
memset(&wtime, 0, sizeof(struct rtc_time));
ppc_md.get_rtc_time(&wtime);
break;
}
case RTC_SET_TIME: /* Set the RTC */
{
struct rtc_time rtc_tm;
unsigned char mon, day, hrs, min, sec, leap_yr;
unsigned int yrs;
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
sizeof(struct rtc_time)))
return -EFAULT;
yrs = rtc_tm.tm_year;
mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm.tm_mday;
hrs = rtc_tm.tm_hour;
min = rtc_tm.tm_min;
sec = rtc_tm.tm_sec;
if (yrs < 70)
return -EINVAL;
leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
if ((mon > 12) || (day == 0))
return -EINVAL;
if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
return -EINVAL;
if ((hrs >= 24) || (min >= 60) || (sec >= 60))
return -EINVAL;
if ( yrs > 169 )
return -EINVAL;
ppc_md.set_rtc_time(&rtc_tm);
return 0;
}
case RTC_EPOCH_READ: /* Read the epoch. */
{
return put_user (epoch, (unsigned long __user *)arg);
}
case RTC_EPOCH_SET: /* Set the epoch. */
{
/*
* There were no RTC clocks before 1900.
*/
if (arg < 1900)
return -EINVAL;
if (!capable(CAP_SYS_TIME))
return -EACCES;
epoch = arg;
return 0;
}
default:
return -EINVAL;
}
return copy_to_user((void __user *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
}
static int rtc_open(struct inode *inode, struct file *file)
{
nonseekable_open(inode, file);
return 0;
}
static int rtc_release(struct inode *inode, struct file *file)
{
return 0;
}
/*
* The various file operations we support.
*/
static struct file_operations rtc_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = rtc_read,
.ioctl = rtc_ioctl,
.open = rtc_open,
.release = rtc_release,
};
static struct miscdevice rtc_dev = {
.minor = RTC_MINOR,
.name = "rtc",
.fops = &rtc_fops
};
static int __init rtc_init(void)
{
int retval;
retval = misc_register(&rtc_dev);
if(retval < 0)
return retval;
#ifdef CONFIG_PROC_FS
if (create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)
== NULL) {
misc_deregister(&rtc_dev);
return -ENOMEM;
}
#endif
printk(KERN_INFO "i/pSeries Real Time Clock Driver v" RTC_VERSION "\n");
return 0;
}
static void __exit rtc_exit (void)
{
remove_proc_entry ("driver/rtc", NULL);
misc_deregister(&rtc_dev);
}
module_init(rtc_init);
module_exit(rtc_exit);
/*
* Info exported via "/proc/driver/rtc".
*/
static int rtc_proc_output (char *buf)
{
char *p;
struct rtc_time tm;
p = buf;
ppc_md.get_rtc_time(&tm);
/*
* There is no way to tell if the luser has the RTC set for local
* time or for Universal Standard Time (GMT). Probably local though.
*/
p += sprintf(p,
"rtc_time\t: %02d:%02d:%02d\n"
"rtc_date\t: %04d-%02d-%02d\n"
"rtc_epoch\t: %04lu\n",
tm.tm_hour, tm.tm_min, tm.tm_sec,
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
p += sprintf(p,
"DST_enable\t: no\n"
"BCD\t\t: yes\n"
"24hr\t\t: yes\n" );
return p - buf;
}
static int rtc_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = 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;
}
#ifdef CONFIG_PPC_RTAS
#define MAX_RTC_WAIT 5000 /* 5 sec */
#define RTAS_CLOCK_BUSY (-2)
unsigned long rtas_get_boot_time(void)
{
int ret[8];
int error, wait_time;
unsigned long max_wait_tb;
max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
do {
error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
wait_time = rtas_extended_busy_delay_time(error);
/* This is boot time so we spin. */
udelay(wait_time*1000);
error = RTAS_CLOCK_BUSY;
}
} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
if (error != 0 && printk_ratelimit()) {
printk(KERN_WARNING "error: reading the clock failed (%d)\n",
error);
return 0;
}
return mktime(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
}
/* NOTE: get_rtc_time will get an error if executed in interrupt context
* and if a delay is needed to read the clock. In this case we just
* silently return without updating rtc_tm.
*/
void rtas_get_rtc_time(struct rtc_time *rtc_tm)
{
int ret[8];
int error, wait_time;
unsigned long max_wait_tb;
max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
do {
error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
if (in_interrupt() && printk_ratelimit()) {
printk(KERN_WARNING "error: reading clock would delay interrupt\n");
return; /* delay not allowed */
}
wait_time = rtas_extended_busy_delay_time(error);
msleep_interruptible(wait_time);
error = RTAS_CLOCK_BUSY;
}
} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
if (error != 0 && printk_ratelimit()) {
printk(KERN_WARNING "error: reading the clock failed (%d)\n",
error);
return;
}
rtc_tm->tm_sec = ret[5];
rtc_tm->tm_min = ret[4];
rtc_tm->tm_hour = ret[3];
rtc_tm->tm_mday = ret[2];
rtc_tm->tm_mon = ret[1] - 1;
rtc_tm->tm_year = ret[0] - 1900;
}
int rtas_set_rtc_time(struct rtc_time *tm)
{
int error, wait_time;
unsigned long max_wait_tb;
max_wait_tb = __get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
do {
error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
tm->tm_year + 1900, tm->tm_mon + 1,
tm->tm_mday, tm->tm_hour, tm->tm_min,
tm->tm_sec, 0);
if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
if (in_interrupt())
return 1; /* probably decrementer */
wait_time = rtas_extended_busy_delay_time(error);
msleep_interruptible(wait_time);
error = RTAS_CLOCK_BUSY;
}
} while (error == RTAS_CLOCK_BUSY && (__get_tb() < max_wait_tb));
if (error != 0 && printk_ratelimit())
printk(KERN_WARNING "error: setting the clock failed (%d)\n",
error);
return 0;
}
#endif
