ns16552.h

著名操作系统Plan 9的第三版的部分核心源代码。现在很难找到了。Plan 9是bell实验室开发的Unix后继者。

/*
 *  PC specific code for the ns16552.  It includes support for the 2 built
 *  in uarts plus up to 5 MP-008 8 uart ISA cards.
 */
enum
{
	Maxcard= 5,		/* max serial cards */
	UartFREQ= 1843200,

	Serial=	0,
	Modem=	1,
};

#define uartwrreg(u,r,v)	outb((u)->port + r, (u)->sticky[r] | (v))
#define uartrdreg(u,r)		inb((u)->port + r)

void	ns16552setup(ulong, ulong, char*, int);
void	ns16552special(int, int, Queue**, Queue**, int (*)(Queue*, int));
void	uartclock(void);
/*
 *  definition of an optional serial card
 */
typedef struct Scard
{
	ISAConf;	/* card configuration */
	int	first;	/* number of first port */
} Scard;
static Scard *scard[Maxcard]; 	/* configs for the serial card */

/* power management currently only makes sense on the AT&T safari */
static void
uartpower(int dev, int onoff)
{
	switch(dev){
	case Modem:
		if((*arch->modempower)(onoff) < 0)
			print("can't turn %s modem speaker\n", onoff?"on":"off");
		break;
	case Serial:
		if((*arch->serialpower)(onoff) < 0)
			print("can't turn %s serial port power\n", onoff?"on":"off");
		break;
	}
}

/*
 *  handle an interrupt to a single uart
 */
static void
ns16552intrx(Ureg*, void* arg)
{
	ns16552intr((ulong)arg);
}

/*
 *  interrupts from the multiport card, MP-008.  A polling port
 *  tells which of 8 devices interrupted.
 */
static void
mp008intr(Ureg* ureg, void* arg)
{
	int i, loops;
	uchar n;
	Scard *mp;

	mp = arg;
	for(loops = 0; loops < 1024; loops++){
		n = ~inb(mp->mem);
		if(n == 0)
			return;
		for(i = 0; n; i++){
			if(n & 1)
				ns16552intrx(ureg, (void*)(mp->first+i));
			n >>= 1;
		}
	}
}

/*
 *  install the uarts (called by reset)
 */
void
ns16552install(void)
{
	int i, j, port, nscard;
	char *p, *q;
	Scard *sc;
	char name[NAMELEN];
	static int already;

	if(already)
		return;
	already = 1;

	/* first two ports are always there and always the normal frequency */
	if(ioalloc(0x3f8, 8, 0, "eia0") < 0)
		print("eia0: port %d in use\n", 0x3f8);
	ns16552setup(0x3F8, UartFREQ, "eia0", Ns550);
	intrenable(IrqUART0, ns16552intrx, (void*)0, BUSUNKNOWN, "eia0");
	if(ioalloc(0x2F8, 8, 0, "eia1") < 0)
		print("eia1: port %d in use\n", 0x2F8);
	ns16552setup(0x2F8, UartFREQ, "eia1", Ns550);
	intrenable(IrqUART1, ns16552intrx, (void*)1, BUSUNKNOWN, "eia1");
	addclock0link(uartclock);

	/* set up a serial console */
	if(p = getconf("console")){
		port = strtol(p, &q, 0);
		if(p != q && (port == 0 || port == 1))
			ns16552special(port, 9600, &kbdq, &printq, kbdcr2nl);
	}

	/* the rest come out of plan9.ini */
	nscard = 0;
	for(i = 0; i < Maxcard; i++){
		sc = scard[nscard] = xalloc(sizeof(Scard));
		if(isaconfig("serial", i, sc) == 0){
			xfree(sc);
			scard[nscard] = 0;
			continue;
		}

		snprint(name, sizeof name, "eia%d00", nscard);
		if(cistrcmp(sc->type, "MP008") == 0){
			/*
			 *  port gives base port address for uarts
			 *  irq is interrupt
			 *  mem is the polling port
			 *  size is the number of serial ports on the same polling port
			 *  freq is the baud rate generator frequency
			 */
			if(sc->size == 0)
				sc->size = 8;
			if(sc->freq == 0)
				sc->freq = UartFREQ;
			sc->first = nuart;
			if(ioalloc(sc->port, 8*sc->size, 0, name) < 0){
				print("mp008: port %lud in use\n", sc->port);
				xfree(sc);
				scard[nscard] = 0;
				continue;
			}
			intrenable(sc->irq, mp008intr, sc, BUSUNKNOWN, name);
			port = sc->port;
			for(j=0; j < sc->size; j++){
				sprint(name, "eia%d%2.2d", nscard, j);
				ns16552setup(port, sc->freq, name, Ns550);
				port += 8;
			}
		} else if(cistrcmp(sc->type, "turbo650") == 0){
			/*
			 *  port gives base port address for the uart
			 *  irq is interrupt
			 *  freq is the baud rate generator frequency
			 */
			if(sc->freq == 0)
				sc->freq = UartFREQ*4;
			if(ioalloc(sc->port, 8, 0, name) < 0){
				print("%s: port %lud in use\n", name, sc->port);
				xfree(sc);
				scard[nscard] = 0;
				continue;
			}
			ns16552setup(sc->port, sc->freq, name, Ns650);

			/*
			 *  multiply clock speed by 4
			 */
			if(sc->mem == 0)
				outb(0x2c8, 0);
			else
				outb(sc->mem, 0);

			intrenable(sc->irq, ns16552intrx, (void*)(nuart-1), BUSUNKNOWN, name);
		} else if(cistrcmp(sc->type, "com") == 0 && sc->port != 0x3F8 && sc->port != 0x2F8){
			/*
			 *  port gives base port address for the uart
			 *  irq is interrupt
			 *  freq is the baud rate generator frequency
			 */
			if(sc->freq == 0)
				sc->freq = UartFREQ;
			if(ioalloc(sc->port, 8, 0, name) < 0){
				print("%s: port %lud in use\n", name, sc->port);
				xfree(sc);
				scard[nscard] = 0;
				continue;
			}
			ns16552setup(sc->port, sc->freq, name, Ns550);
			intrenable(sc->irq, ns16552intrx, (void*)(nuart-1), BUSUNKNOWN, name);
		}
		nscard++;
	}
}