ref: 61f4c085c402af665b436f6d010d61107551d8a3
dir: /sys/src/9/kw/devrtc.c/
/*
* devrtc - real-time clock, for kirkwood
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "io.h"
typedef struct RtcReg RtcReg;
typedef struct Rtc Rtc;
struct RtcReg
{
ulong time;
ulong date;
ulong alarmtm;
ulong alarmdt;
ulong intrmask;
ulong intrcause;
};
struct Rtc
{
int sec;
int min;
int hour;
int wday;
int mday;
int mon;
int year;
};
enum {
Qdir,
Qrtc,
};
static Dirtab rtcdir[] = {
".", {Qdir, 0, QTDIR}, 0, 0555,
"rtc", {Qrtc}, NUMSIZE, 0664,
};
static RtcReg *rtcreg; /* filled in by attach */
static Lock rtclock;
#define SEC2MIN 60
#define SEC2HOUR (60*SEC2MIN)
#define SEC2DAY (24L*SEC2HOUR)
/*
* days per month plus days/year
*/
static int dmsize[] =
{
365, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
static int ldmsize[] =
{
366, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
/*
* return the days/month for the given year
*/
static int *
yrsize(int yr)
{
if((yr % 4) == 0)
return ldmsize;
else
return dmsize;
}
/*
* compute seconds since Jan 1 1970
*/
static ulong
rtc2sec(Rtc *rtc)
{
ulong secs;
int i;
int *d2m;
/*
* seconds per year
*/
secs = 0;
for(i = 1970; i < rtc->year; i++){
d2m = yrsize(i);
secs += d2m[0] * SEC2DAY;
}
/*
* seconds per month
*/
d2m = yrsize(rtc->year);
for(i = 1; i < rtc->mon; i++)
secs += d2m[i] * SEC2DAY;
secs += (rtc->mday-1) * SEC2DAY;
secs += rtc->hour * SEC2HOUR;
secs += rtc->min * SEC2MIN;
secs += rtc->sec;
return secs;
}
/*
* compute rtc from seconds since Jan 1 1970
*/
static void
sec2rtc(ulong secs, Rtc *rtc)
{
int d;
long hms, day;
int *d2m;
/*
* break initial number into days
*/
hms = secs % SEC2DAY;
day = secs / SEC2DAY;
if(hms < 0) {
hms += SEC2DAY;
day -= 1;
}
/*
* 19700101 was thursday
*/
rtc->wday = (day + 7340036L) % 7;
/*
* generate hours:minutes:seconds
*/
rtc->sec = hms % 60;
d = hms / 60;
rtc->min = d % 60;
d /= 60;
rtc->hour = d;
/*
* year number
*/
if(day >= 0)
for(d = 1970; day >= *yrsize(d); d++)
day -= *yrsize(d);
else
for (d = 1970; day < 0; d--)
day += *yrsize(d-1);
rtc->year = d;
/*
* generate month
*/
d2m = yrsize(rtc->year);
for(d = 1; day >= d2m[d]; d++)
day -= d2m[d];
rtc->mday = day + 1;
rtc->mon = d;
}
enum {
Rtcsec = 0x00007f,
Rtcmin = 0x007f00,
Rtcms = 8,
Rtchr12 = 0x1f0000,
Rtchr24 = 0x3f0000,
Rtchrs = 16,
Rdmday = 0x00003f,
Rdmon = 0x001f00,
Rdms = 8,
Rdyear = 0x7f0000,
Rdys = 16,
Rtcpm = 1<<21, /* pm bit */
Rtc12 = 1<<22, /* 12 hr clock */
};
static ulong
bcd2dec(ulong bcd)
{
ulong d, m, i;
d = 0;
m = 1;
for(i = 0; i < 2 * sizeof d; i++){
d += ((bcd >> (4*i)) & 0xf) * m;
m *= 10;
}
return d;
}
static ulong
dec2bcd(ulong d)
{
ulong bcd, i;
bcd = 0;
for(i = 0; d != 0; i++){
bcd |= (d%10) << (4*i);
d /= 10;
}
return bcd;
}
static long
_rtctime(void)
{
ulong t, d;
Rtc rtc;
t = rtcreg->time;
d = rtcreg->date;
rtc.sec = bcd2dec(t & Rtcsec);
rtc.min = bcd2dec((t & Rtcmin) >> Rtcms);
if(t & Rtc12){
rtc.hour = bcd2dec((t & Rtchr12) >> Rtchrs) - 1; /* 1—12 */
if(t & Rtcpm)
rtc.hour += 12;
}else
rtc.hour = bcd2dec((t & Rtchr24) >> Rtchrs); /* 0—23 */
rtc.mday = bcd2dec(d & Rdmday); /* 1—31 */
rtc.mon = bcd2dec((d & Rdmon) >> Rdms); /* 1—12 */
rtc.year = bcd2dec((d & Rdyear) >> Rdys) + 2000; /* year%100 */
// print("%0.2d:%0.2d:%.02d %0.2d/%0.2d/%0.2d\n", /* HH:MM:SS YY/MM/DD */
// rtc.hour, rtc.min, rtc.sec, rtc.year, rtc.mon, rtc.mday);
return rtc2sec(&rtc);
}
long
rtctime(void)
{
int i;
long t, ot;
ilock(&rtclock);
/* loop until we get two reads in a row the same */
t = _rtctime();
ot = ~t;
for(i = 0; i < 100 && ot != t; i++){
ot = t;
t = _rtctime();
}
if(ot != t)
print("rtctime: we are boofheads\n");
iunlock(&rtclock);
return t;
}
static void
setrtc(Rtc *rtc)
{
ilock(&rtclock);
rtcreg->time = dec2bcd(rtc->wday) << 24 | dec2bcd(rtc->hour) << 16 |
dec2bcd(rtc->min) << 8 | dec2bcd(rtc->sec);
rtcreg->date = dec2bcd(rtc->year - 2000) << 16 |
dec2bcd(rtc->mon) << 8 | dec2bcd(rtc->mday);
iunlock(&rtclock);
}
static Chan*
rtcattach(char *spec)
{
rtcreg = (RtcReg*)soc.rtc;
return devattach(L'r', spec);
}
static Walkqid*
rtcwalk(Chan *c, Chan *nc, char **name, int nname)
{
return devwalk(c, nc, name, nname, rtcdir, nelem(rtcdir), devgen);
}
static int
rtcstat(Chan *c, uchar *dp, int n)
{
return devstat(c, dp, n, rtcdir, nelem(rtcdir), devgen);
}
static Chan*
rtcopen(Chan *c, int omode)
{
return devopen(c, omode, rtcdir, nelem(rtcdir), devgen);
}
static void
rtcclose(Chan*)
{
}
static long
rtcread(Chan *c, void *buf, long n, vlong off)
{
if(c->qid.type & QTDIR)
return devdirread(c, buf, n, rtcdir, nelem(rtcdir), devgen);
switch((ulong)c->qid.path){
default:
error(Egreg);
case Qrtc:
return readnum(off, buf, n, rtctime(), NUMSIZE);
}
}
static long
rtcwrite(Chan *c, void *buf, long n, vlong off)
{
ulong offset = off;
char *cp, sbuf[32];
Rtc rtc;
switch((ulong)c->qid.path){
default:
error(Egreg);
case Qrtc:
if(offset != 0 || n >= sizeof(sbuf)-1)
error(Ebadarg);
memmove(sbuf, buf, n);
sbuf[n] = '\0';
for(cp = sbuf; *cp != '\0'; cp++)
if(*cp >= '0' && *cp <= '9')
break;
sec2rtc(strtoul(cp, 0, 0), &rtc);
setrtc(&rtc);
return n;
}
}
Dev rtcdevtab = {
L'r',
"rtc",
devreset,
devinit,
devshutdown,
rtcattach,
rtcwalk,
rtcstat,
rtcopen,
devcreate,
rtcclose,
rtcread,
devbread,
rtcwrite,
devbwrite,
devremove,
devwstat,
devpower,
};