#include	"u.h"#include	"../port/lib.h"#include	"mem.h"#include	"dat.h"#include	"fns.h"#include	"../port/error.h"#include	"devtab.h" #include	"io.h" typedef struct Rtc	Rtc;typedef struct Nvram	Nvram; /* * length of nvram is 2048 * the last addresses are reserved by convention for * a checksum and setting the real time clock */enum{	NVLEN	= 2046,	NVCKSUM = 2046,	NVRTC	= 2047,	Nbcd = 8,	/* number of bcd bytes in the clock */	Qrtc = 1,	Qnvram,}; struct Nvram{	uchar	val;	uchar	pad[7];}; struct Rtc{	int	sec;	int	min;	int	hour;	int	mday;	int	mon;	int	year;}; QLock	rtclock;		/* mutex on nvram operations */ static Dirtab rtcdir[]={	"rtc",		{Qrtc, 0},	0,	0644,	"nvram",	{Qnvram, 0},	0,	0600,};#define	NRTC	(sizeof(rtcdir)/sizeof(rtcdir[0])) static uchar pattern[] ={	0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c}; ulong	rtc2sec(Rtc*);void	sec2rtc(ulong, Rtc*);int	*yrsize(int);void	setrtc(Rtc*);long	rtctime(void);void	nvcksum(void); voidrtcreset(void){} voidrtcinit(void){} Chan*rtcattach(char *spec){	return devattach('r', spec);} Chan*rtcclone(Chan *c, Chan *nc){	return devclone(c, nc);} int	 rtcwalk(Chan *c, char *name){	return devwalk(c, name, rtcdir, NRTC, devgen);} void	 rtcstat(Chan *c, char *dp){	devstat(c, dp, rtcdir, NRTC, devgen);} Chan*rtcopen(Chan *c, int omode){	omode = openmode(omode);	switch(c->qid.path){	case Qrtc:		if(strcmp(u->p->user, eve)!=0 && omode!=OREAD)			error(Eperm);		break;	case Qnvram:		if(strcmp(u->p->user, eve)!=0 || !cpuserver)			error(Eperm);	}	return devopen(c, omode, rtcdir, NRTC, devgen);} void	 rtccreate(Chan *c, char *name, int omode, ulong perm){	USED(c);	USED(name);	USED(omode);	USED(perm);	error(Eperm);} void	 rtcclose(Chan *c){	USED(c);} long	 rtcread(Chan *c, void *buf, long n, ulong offset){	Nvram *nv;	char *p;	ulong t, ot;	int i; 	if(c->qid.path & CHDIR)		return devdirread(c, buf, n, rtcdir, NRTC, devgen); 	switch(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 > NVLEN)			return 0;		if(n > NVLEN - offset)			n = NVLEN - offset;		nv = (Nvram *)NVRAM;		p = buf;		qlock(&rtclock);		for(i = 0; i < n; i++)			p[i] = nv[i+offset].val;		qunlock(&rtclock);		return n;	}	error(Egreg);	return -1;		/* never reached */} long	 rtcwrite(Chan *c, void *buf, long n, ulong offset){	Nvram *nv;	Rtc rtc;	ulong secs;	char *cp, *ep;	int i; 	switch(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:		if(offset > NVLEN)			return 0;		if(n > NVLEN - offset)			n = NVLEN - offset;		nv = (Nvram *)NVRAM;		qlock(&rtclock);		for(i = 0; i < n; i++)			nv[i+offset].val = ((char*)buf)[i];		nvcksum();		qunlock(&rtclock);		return n;	}	error(Egreg);	return -1;		/* never reached */} void	 rtcremove(Chan *c){	USED(c);	error(Eperm);} void	 rtcwstat(Chan *c, char *dp){	USED(c);	USED(dp);	error(Eperm);} voidnvcksum(void){	Nvram *nv;	uchar cksum;	int i; 	/*	 * Seed the checksum so all-zeroes (all-ones) nvram doesn't have a zero	 * (all-ones) checksum.	 */	cksum = 0xa5;	nv = (Nvram *)NVRAM;	for(i = 0; i < NVLEN; i++){		cksum ^= nv[i].val;		cksum = (cksum << 1) | ((cksum >> 7) & 1);	}	nv[NVCKSUM].val = cksum;} /* *  issue pattern recognition bits to nv ram to address the *  real time clock */voidrtcpattern(void){	uchar *nv;	uchar ch;	int i, j; 	nv = &((Nvram*)NVRAM)[NVRTC].val; 	/*	 *  read the pattern sequence pointer to reset it	 */	ch = *nv;	USED(ch); 	/*	 *  stuff the pattern recognition codes one bit at	 *  a time into *nv.	 */	for(i = 0; i < Nbcd; i++){		ch = pattern[i];		for (j = 0; j < 8; j++){			*nv = ch & 0x1;			ch >>= 1;		}	}} #define GETBCD(o) ((bcdclock[o]&0xf) + 10*(bcdclock[o]>>4)) long	 rtctime(void){	int i,j;	uchar ch;	uchar *nv;	uchar bcdclock[Nbcd];	Rtc rtc; 	nv = &((Nvram*)NVRAM)[NVRTC].val; 	/*	 *  set up the pattern for the clock	 */	rtcpattern(); 	/*	 *  read out the clock one bit at a time	 */	for(i = 0; i < Nbcd; i++){		ch = 0;		for (j = 0; j < 8; j++)			ch |= ((*nv & 0x1) << j);		bcdclock[i] = ch;	} 	/*	 *  see if the clock oscillator is on	 */	if(bcdclock[4] & 0x20)		return 0;		/* nope, time is bogus */ 	/*	 *  convert from BCD	 */	rtc.sec = GETBCD(1);	rtc.min = GETBCD(2);	rtc.hour = GETBCD(3);	rtc.mday = GETBCD(5);	rtc.mon = GETBCD(6);	rtc.year = GETBCD(7); 	/*	 *  the world starts jan 1 1970	 */	if(rtc.year < 70)		rtc.year += 2000;	else		rtc.year += 1900;	return rtc2sec(&rtc);} #define PUTBCD(n,o) bcdclock[o] = (n % 10) | (((n / 10) % 10)<<4) voidsetrtc(Rtc *rtc){	int i, j;	uchar ch;	uchar bcdclock[Nbcd];	uchar *nv; 	bcdclock[0] = bcdclock[4] = 0;	PUTBCD(rtc->sec, 1);	PUTBCD(rtc->min, 2);	PUTBCD(rtc->hour, 3);	PUTBCD(rtc->mday, 5);	PUTBCD(rtc->mon, 6);	PUTBCD(rtc->year, 7); 	/*	 *  set up the pattern for the clock	 */	rtcpattern(); 	/*	 *  write the clock one bit at a time	 */	nv = &((Nvram*)NVRAM)[NVRTC].val;	for(i = 0; i < Nbcd; i++){		ch = bcdclock[i];		for (j = 0; j < 8; j++){			*nv = ch & 1;			ch >>= 1;		}	}} #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 */int *yrsize(int yr){	if((yr % 4) == 0)		return ldmsize;	else		return dmsize;} /* *  compute seconds since Jan 1 1970 */ulongrtc2sec(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 */voidsec2rtc(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;}