ref: fa9f4c5c6852ce467644f610e77504664cb86af4
dir: /os/js/devrtc.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "io.h"
/*
* Mostek MK48T12-15 Zeropower/Timekeeper
* This driver is actually portable.
*/
typedef struct Rtc Rtc;
struct Rtc
{
int sec;
int min;
int hour;
int wday;
int mday;
int mon;
int year;
};
static uchar rtcgencksum(void);
static void setrtc(Rtc *rtc);
static long rtctime(void);
static int *yrsize(int yr);
static int *yrsize(int yr);
static ulong rtc2sec(Rtc *rtc);
static void sec2rtc(ulong secs, Rtc *rtc);
static struct
{
uchar *cksum;
uchar *ram;
RTCdev *rtc;
}nvr;
enum{
Qdir,
Qrtc,
Qnvram,
};
QLock rtclock; /* mutex on clock operations */
static Dirtab rtcdir[]={
".", {Qdir, 0, QTDIR}, 0, 0555,
"rtc", {Qrtc, 0}, 0, 0666,
"nvram", {Qnvram, 0}, NVWRITE, 0666,
};
#define NRTC (sizeof(rtcdir)/sizeof(rtcdir[0]))
static void
rtcinit(void)
{
KMap *k;
k = kmappa(NVR_CKSUM_PHYS, PTENOCACHE|PTEIO);
nvr.cksum = (uchar*)VA(k);
k = kmappa(NVR_PHYS, PTENOCACHE|PTEIO);
nvr.ram = (uchar*)VA(k);
nvr.rtc = (RTCdev*)(VA(k)+RTCOFF);
rtcgencksum();
}
static Chan*
rtcattach(char *spec)
{
return devattach('r',spec);
}
static Walkqid*
rtcwalk(Chan *c, Chan *nc, char **name, int nname)
{
return devwalk(c, nc, name, nname, rtcdir, NRTC, devgen);
}
static int
rtcstat(Chan *c, uchar *dp, int n)
{
return devstat(c, dp, n, rtcdir, NRTC, devgen);
}
static Chan*
rtcopen(Chan *c, int omode)
{
omode = openmode(omode);
switch((ulong)c->qid.path){
case Qrtc:
if(strcmp(up->env->user, eve)!=0 && omode!=OREAD)
error(Eperm);
break;
case Qnvram:
if(strcmp(up->env->user, eve)!=0)
error(Eperm);
}
return devopen(c, omode, rtcdir, NRTC, devgen);
}
static void
rtccreate(Chan *c, char *name, int omode, ulong perm)
{
USED(c, name, omode, perm);
error(Eperm);
}
static void
rtcclose(Chan *c)
{
USED(c);
}
static long
rtcread(Chan *c, void *buf, long n, vlong offset)
{
ulong t, ot;
if(c->qid.type & QTDIR)
return devdirread(c, buf, n, rtcdir, NRTC, devgen);
switch((ulong)c->qid.path){
case Qrtc:
qlock(&rtclock);
t = rtctime();
do{
ot = t;
t = rtctime(); /* make sure there's no skew */
}while(t != ot);
qunlock(&rtclock);
n = readnum(offset, buf, n, t, 12);
return n;
case Qnvram:
if(offset > NVREAD)
return 0;
if(n > NVREAD - offset)
n = NVREAD - offset;
qlock(&rtclock);
memmove(buf, nvr.ram+offset, n);
qunlock(&rtclock);
return n;
}
error(Egreg);
return 0; /* not reached */
}
/*
* XXX - Tad: fixme to generate the correct checksum
*/
static uchar
rtcgencksum(void)
{
uchar cksum;
int i;
static uchar p1cksum = 0;
static uchar p1cksumvalid=0;
if(!p1cksumvalid) {
for(i=1; i < 0x1000 ; i++)
p1cksum ^= nvr.cksum[i];
p1cksumvalid = 1;
}
cksum = p1cksum;
for(i=0; i < 0xfdf ; i++) {
cksum ^= nvr.ram[i];
}
return cksum;
}
static long
rtcwrite(Chan *c, void *buf, long n, vlong offset)
{
Rtc rtc;
ulong secs;
char *cp, sbuf[32];
switch((ulong)c->qid.path){
case Qrtc:
/*
* read the time
*/
if(offset != 0 || n >= sizeof(sbuf)-1)
error(Ebadarg);
memmove(sbuf, buf, n);
sbuf[n] = '\0';
cp = sbuf;
while(*cp){
if(*cp>='0' && *cp<='9')
break;
cp++;
}
secs = strtoul(cp, 0, 0);
/*
* convert to bcd
*/
sec2rtc(secs, &rtc);
/*
* write it
*/
qlock(&rtclock);
setrtc(&rtc);
qunlock(&rtclock);
return n;
case Qnvram:
if(offset > NVWRITE)
return 0;
if(n > NVWRITE - offset)
n = NVWRITE - offset;
qlock(&rtclock);
memmove(nvr.ram+offset, buf, n);
*nvr.cksum = rtcgencksum();
qunlock(&rtclock);
return n;
}
error(Egreg);
return 0; /* not reached */
}
#define bcd2dec(bcd) (((((bcd)>>4) & 0x0F) * 10) + ((bcd) & 0x0F))
#define dec2bcd(dec) ((((dec)/10)<<4)|((dec)%10))
static void
setrtc(Rtc *rtc)
{
struct RTCdev *dev;
dev = nvr.rtc;
dev->control |= RTCWRITE;
wbflush();
dev->year = dec2bcd(rtc->year % 100);
dev->mon = dec2bcd(rtc->mon);
dev->mday = dec2bcd(rtc->mday);
dev->hour = dec2bcd(rtc->hour);
dev->min = dec2bcd(rtc->min);
dev->sec = dec2bcd(rtc->sec);
wbflush();
dev->control &= ~RTCWRITE;
wbflush();
}
static long
rtctime(void)
{
struct RTCdev *dev;
Rtc rtc;
dev = nvr.rtc;
dev->control |= RTCREAD;
wbflush();
rtc.sec = bcd2dec(dev->sec) & 0x7F;
rtc.min = bcd2dec(dev->min & 0x7F);
rtc.hour = bcd2dec(dev->hour & 0x3F);
rtc.mday = bcd2dec(dev->mday & 0x3F);
rtc.mon = bcd2dec(dev->mon & 0x3F);
rtc.year = bcd2dec(dev->year);
dev->control &= ~RTCREAD;
wbflush();
if (rtc.mon < 1 || rtc.mon > 12)
return 0;
/*
* the world starts Jan 1 1970
*/
if(rtc.year < 70)
rtc.year += 2000;
else
rtc.year += 1900;
return rtc2sec(&rtc);
}
#define SEC2MIN 60L
#define SEC2HOUR (60L*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;
secs = 0;
/*
* seconds per year
*/
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;
}
/*
* 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;
return;
}
Dev rtcdevtab = {
'r',
"rtc",
devreset,
rtcinit,
devshutdown,
rtcattach,
rtcwalk,
rtcstat,
rtcopen,
rtccreate,
rtcclose,
rtcread,
devbread,
rtcwrite,
devbwrite,
devremove,
devwstat,
};