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/*
 * stuff for dealing with io nexus on stars
 * probably nearly identical to 8600
 */

#include "sys/param.h"
#include "sys/nexus.h"
#include "sys/nxaddr.h"
#include "sys/pte.h"

static int nexcnt;
char *iospace;		/* an array of struct nexus */

static int nexreg(), nexwind();

/*
 * how much address space
 * is needed for nexus space?
 * needed when allocating system page table
 */

mchiopsize()
{
	register int i;

	for (i = 0; nextab[i].bus >= 0; i++)
		;
	nexcnt = i;
	return (i * sizeof(struct nexus));
}

/*
 * map appropriate parts of nexus space into kernel space
 * called early on, before memory mapping is set up
 * argument is the first relevant spt entry
 */

mchiopinit(pt)
struct pte *pt;
{
	register long *p;
	register int i, n;
	register int b;

	p = (long *)pt;
	for (i = 0; i < nexcnt; i++) {
		b = nexreg(&nextab[i]);
		for (n = 0; n < btoc(NXSIZE); n++)
			if (b)
				*p++ = PG_V|PG_KW|(b+n);
			else
				*p++ = 0;
		b = nexwind(&nextab[i]);
		for (n = 0; n < btoc(NXWSIZE); n++)
			if (b)
				*p++ = PG_V|PG_KW|(b+n);
			else
				*p++ = 0;
	}
}

static
nexreg(n)
register struct nextab *n;
{
	if (n->bus)
		return (0);	/* only one SBI */
	if (n->adp >= 16)
		return (0);
	return (btoc(n->adp * NXSIZE + 0x20000000));
}

#define	FIRSTUBA 3
#define	LASTUBA	(FIRSTUBA+4)

static
nexwind(n)
register struct nextab *n;
{
	if (n->bus)
		return (0);	/* only one SBI */
	if (n->adp < FIRSTUBA || n->adp > LASTUBA)
		return (0);	/* only UBAs have windows */
	return (btoc(0x20100000+(n->adp - FIRSTUBA)*01000000));
}

caddr_t
nxaddr(np)
register struct nxaddr *np;
{
	if (np->adno != 0)
		return (0);
	if (np->nexus < 0 || np->nexus >= nexcnt)
		return (0);
	return((caddr_t)(iospace + np->nexus*sizeof(struct nexus)));
}

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