ref: cd747191012d0420ac631340d962da1f80cef0a5
dir: /sys/src/9/mtx/devrtc.c/
/*
* M48T59/559 Timekeeper
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "io.h"
enum{
STB0 = 0x74,
STB1 = 0x75,
Data = 0x77,
NVOFF= 0,
NVLEN= 0x1ff0, /* length in bytes of NV RAM */
/*
* register offsets into time of day clock
*/
NVflags= 0x1ff0,
NVwatchdog= 0x1ff7,
NVctl= 0x1ff8,
NVsec,
NVmin,
NVhour,
NVday, /* (1 = Sun) */
NVmday, /* (1-31) */
NVmon, /* (1-12) */
NVyear, /* (0-99) */
/* NVctl */
RTwrite = (1<<7),
RTread = (1<<6),
RTsign = (1<<5),
RTcal = 0x1f,
/* NVwatchdog */
WDsteer = (1<<7), /* 0 -> intr, 1 -> reset */
WDmult = (1<<2), /* 5 bits of multiplier */
WDres0 = (0<<0), /* 1/16 sec resolution */
WDres1 = (1<<0), /* 1/4 sec resolution */
WDres2 = (2<<0), /* 1 sec resolution */
WDres3 = (3<<0), /* 4 sec resolution */
Qdir = 0,
Qrtc,
Qnvram,
};
/*
* broken down time
*/
typedef struct
{
int sec;
int min;
int hour;
int mday;
int mon;
int year;
} Rtc;
QLock rtclock; /* mutex on nvram operations */
static Dirtab rtcdir[]={
".", {Qdir, 0, QTDIR}, 0, DMDIR|0555,
"rtc", {Qrtc, 0}, 0, 0644,
"nvram", {Qnvram, 0}, 0, 0600,
};
static ulong rtc2sec(Rtc*);
static void sec2rtc(ulong, Rtc*);
static void setrtc(Rtc*);
static void nvcksum(void);
static void nvput(int, uchar);
static uchar nvget(int);
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, 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)
{
omode = openmode(omode);
switch((ulong)c->qid.path){
case Qrtc:
if(strcmp(up->user, eve)!=0 && omode!=OREAD)
error(Eperm);
break;
case Qnvram:
if(strcmp(up->user, eve)!=0 || !cpuserver)
error(Eperm);
}
return devopen(c, omode, rtcdir, nelem(rtcdir), devgen);
}
static void
rtcclose(Chan*)
{
}
static long
rtcread(Chan *c, void *buf, long n, vlong off)
{
char *p;
ulong t;
int i;
ulong offset = off;
if(c->qid.type & QTDIR)
return devdirread(c, buf, n, rtcdir, nelem(rtcdir), devgen);
switch((ulong)c->qid.path){
case Qrtc:
qlock(&rtclock);
t = rtctime();
qunlock(&rtclock);
n = readnum(offset, buf, n, t, 12);
return n;
case Qnvram:
offset += NVOFF;
if(offset > NVLEN)
return 0;
if(n > NVLEN - offset)
n = NVLEN - offset;
p = buf;
qlock(&rtclock);
for(i = 0; i < n; i++)
p[i] = nvget(i+offset);
qunlock(&rtclock);
return n;
}
error(Egreg);
return -1; /* never reached */
}
static long
rtcwrite(Chan *c, void *buf, long n, vlong off)
{
Rtc rtc;
ulong secs;
char *cp, *ep;
int i;
ulong offset = off;
switch((ulong)c->qid.path){
case Qrtc:
if(offset!=0)
error(Ebadarg);
/*
* read the time
*/
cp = ep = buf;
ep += n;
while(cp < ep){
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:
offset += NVOFF;
if(offset > NVLEN)
return 0;
if(n > NVLEN - offset)
n = NVLEN - offset;
qlock(&rtclock);
for(i = 0; i < n; i++)
nvput(i+offset, ((uchar*)buf)[i]);
nvcksum();
qunlock(&rtclock);
return n;
}
error(Egreg);
return -1; /* never reached */
}
long
rtcbwrite(Chan *c, Block *bp, ulong offset)
{
return devbwrite(c, bp, offset);
}
Dev rtcdevtab = {
'r',
"rtc",
devreset,
devinit,
devshutdown,
rtcattach,
rtcwalk,
rtcstat,
rtcopen,
devcreate,
rtcclose,
rtcread,
devbread,
rtcwrite,
devbwrite,
devremove,
devwstat,
};
static void
nvput(int offset, uchar val)
{
outb(STB0, offset);
outb(STB1, offset>>8);
outb(Data, val);
}
static uchar
nvget(int offset)
{
outb(STB0, offset);
outb(STB1, offset>>8);
return inb(Data);
}
static void
nvcksum(void)
{
}
void
watchreset(void)
{
splhi();
nvput(NVwatchdog, WDsteer|(1*WDmult)|WDres0);
for(;;);
}
static int
getbcd(int bcd)
{
return (bcd&0x0f) + 10 * (bcd>>4);
}
static int
putbcd(int val)
{
return (val % 10) | (((val/10) % 10) << 4);
}
long
rtctime(void)
{
int ctl;
Rtc rtc;
/*
* convert from BCD
*/
ctl = nvget(NVctl);
ctl &= RTsign|RTcal;
nvput(NVctl, ctl|RTread);
rtc.sec = getbcd(nvget(NVsec) & 0x7f);
rtc.min = getbcd(nvget(NVmin));
rtc.hour = getbcd(nvget(NVhour));
rtc.mday = getbcd(nvget(NVmday));
rtc.mon = getbcd(nvget(NVmon));
rtc.year = getbcd(nvget(NVyear));
if(rtc.year < 70)
rtc.year += 2000;
else
rtc.year += 1900;
nvput(NVctl, ctl);
return rtc2sec(&rtc);
}
static void
setrtc(Rtc *rtc)
{
int ctl;
ctl = nvget(NVctl);
ctl &= RTsign|RTcal;
nvput(NVctl, ctl|RTwrite);
nvput(NVsec, putbcd(rtc->sec));
nvput(NVmin, putbcd(rtc->min));
nvput(NVhour, putbcd(rtc->hour));
nvput(NVmday, putbcd(rtc->mday));
nvput(NVmon, putbcd(rtc->mon));
nvput(NVyear, putbcd(rtc->year % 100));
nvput(NVctl, ctl);
}
#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 y)
{
if((y%4) == 0 && ((y%100) != 0 || (y%400) == 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;
}