ref: db3b70f1424dfd8c5ea45206790df066c53bfab0
dir: /os/pc/devrtc.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
/*
* real time clock and non-volatile ram
*/
enum {
Paddr= 0x70, /* address port */
Pdata= 0x71, /* data port */
Seconds= 0x00,
Minutes= 0x02,
Hours= 0x04,
Mday= 0x07,
Month= 0x08,
Year= 0x09,
Status= 0x0A,
Nvoff= 128, /* where usable nvram lives */
Nvsize= 256,
Nbcd= 6,
};
typedef struct Rtc Rtc;
struct Rtc
{
int sec;
int min;
int hour;
int mday;
int mon;
int year;
};
enum{
Qdir = 0,
Qrtc,
Qnvram,
};
Dirtab rtcdir[]={
".", {Qdir, 0, QTDIR}, 0, 0555,
"nvram", {Qnvram, 0}, Nvsize, 0664,
"rtc", {Qrtc, 0}, 0, 0664,
};
static ulong rtc2sec(Rtc*);
static void sec2rtc(ulong, Rtc*);
void
rtcinit(void)
{
if(ioalloc(Paddr, 2, 0, "rtc/nvr") < 0)
panic("rtcinit: ioalloc failed");
}
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->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, nelem(rtcdir), devgen);
}
static void
rtcclose(Chan*)
{
}
#define GETBCD(o) ((bcdclock[o]&0xf) + 10*(bcdclock[o]>>4))
static long
_rtctime(void)
{
uchar bcdclock[Nbcd];
Rtc rtc;
int i;
/* don't do the read until the clock is no longer busy */
for(i = 0; i < 10000; i++){
outb(Paddr, Status);
if(inb(Pdata) & 0x80)
continue;
/* read clock values */
outb(Paddr, Seconds); bcdclock[0] = inb(Pdata);
outb(Paddr, Minutes); bcdclock[1] = inb(Pdata);
outb(Paddr, Hours); bcdclock[2] = inb(Pdata);
outb(Paddr, Mday); bcdclock[3] = inb(Pdata);
outb(Paddr, Month); bcdclock[4] = inb(Pdata);
outb(Paddr, Year); bcdclock[5] = inb(Pdata);
outb(Paddr, Status);
if((inb(Pdata) & 0x80) == 0)
break;
}
/*
* convert from BCD
*/
rtc.sec = GETBCD(0);
rtc.min = GETBCD(1);
rtc.hour = GETBCD(2);
rtc.mday = GETBCD(3);
rtc.mon = GETBCD(4);
rtc.year = GETBCD(5);
/*
* the world starts jan 1 1970
*/
if(rtc.year < 70)
rtc.year += 2000;
else
rtc.year += 1900;
return rtc2sec(&rtc);
}
static Lock nvrtlock;
long
rtctime(void)
{
int i;
long t, ot;
ilock(&nvrtlock);
/* loop till we get two reads in a row the same */
t = _rtctime();
for(i = 0; i < 100; i++){
ot = t;
t = _rtctime();
if(ot == t)
break;
}
if(i == 100) print("we are boofheads\n");
iunlock(&nvrtlock);
return t;
}
static long
rtcread(Chan* c, void* buf, long n, vlong off)
{
ulong t;
char *a, *start;
ulong offset = off;
if(c->qid.type & QTDIR)
return devdirread(c, buf, n, rtcdir, nelem(rtcdir), devgen);
switch((ulong)c->qid.path){
case Qrtc:
t = rtctime();
n = readnum(offset, buf, n, t, 12);
return n;
case Qnvram:
if(n == 0)
return 0;
if(n > Nvsize)
n = Nvsize;
a = start = smalloc(n);
ilock(&nvrtlock);
for(t = offset; t < offset + n; t++){
if(t >= Nvsize)
break;
outb(Paddr, Nvoff+t);
*a++ = inb(Pdata);
}
iunlock(&nvrtlock);
if(waserror()){
free(start);
nexterror();
}
memmove(buf, start, t - offset);
poperror();
free(start);
return t - offset;
}
error(Ebadarg);
return 0;
}
#define PUTBCD(n,o) bcdclock[o] = (n % 10) | (((n / 10) % 10)<<4)
static long
rtcwrite(Chan* c, void* buf, long n, vlong off)
{
int t;
char *a, *start;
Rtc rtc;
ulong secs;
uchar bcdclock[Nbcd];
char *cp, *ep;
ulong offset = off;
if(offset!=0)
error(Ebadarg);
switch((ulong)c->qid.path){
case Qrtc:
/*
* 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);
PUTBCD(rtc.sec, 0);
PUTBCD(rtc.min, 1);
PUTBCD(rtc.hour, 2);
PUTBCD(rtc.mday, 3);
PUTBCD(rtc.mon, 4);
PUTBCD(rtc.year, 5);
/*
* write the clock
*/
ilock(&nvrtlock);
outb(Paddr, Seconds); outb(Pdata, bcdclock[0]);
outb(Paddr, Minutes); outb(Pdata, bcdclock[1]);
outb(Paddr, Hours); outb(Pdata, bcdclock[2]);
outb(Paddr, Mday); outb(Pdata, bcdclock[3]);
outb(Paddr, Month); outb(Pdata, bcdclock[4]);
outb(Paddr, Year); outb(Pdata, bcdclock[5]);
iunlock(&nvrtlock);
return n;
case Qnvram:
if(n == 0)
return 0;
if(n > Nvsize)
n = Nvsize;
start = a = smalloc(n);
if(waserror()){
free(start);
nexterror();
}
memmove(a, buf, n);
poperror();
ilock(&nvrtlock);
for(t = offset; t < offset + n; t++){
if(t >= Nvsize)
break;
outb(Paddr, Nvoff+t);
outb(Pdata, *a++);
}
iunlock(&nvrtlock);
free(start);
return t - offset;
}
error(Ebadarg);
return 0;
}
Dev rtcdevtab = {
'r',
"rtc",
devreset,
rtcinit,
devshutdown,
rtcattach,
rtcwalk,
rtcstat,
rtcopen,
devcreate,
rtcclose,
rtcread,
devbread,
rtcwrite,
devbwrite,
devremove,
devwstat,
};
#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;
}
uchar
nvramread(int addr)
{
uchar data;
ilock(&nvrtlock);
outb(Paddr, addr);
data = inb(Pdata);
iunlock(&nvrtlock);
return data;
}
void
nvramwrite(int addr, uchar data)
{
ilock(&nvrtlock);
outb(Paddr, addr);
outb(Pdata, data);
iunlock(&nvrtlock);
}