1 files changed, 461 insertions, 0 deletions
diff --git a/os/pc/devrtc.c b/os/pc/devrtc.c
new file mode 100644
index 00000000..f6e1d911
--- /dev/null
+++ b/os/pc/devrtc.c
@@ -0,0 +1,461 @@
+#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);
+}