/*	$OpenBSD: prom.c,v 1.1 2023/03/11 20:56:01 miod Exp $	*/
/*	$NetBSD: prom.c,v 1.2 1996/11/25 16:18:16 cgd Exp $	*/

/*  
 * Mach Operating System
 * Copyright (c) 1992 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */

#include <lib/libsa/stand.h>

#include <sys/types.h>
#include <machine/rpb.h>
#include <machine/prom.h>

void
init_prom_calls()
{
	extern struct prom_vec prom_dispatch_v;
	struct rpb *r;
	struct crb *c;

	r = (struct rpb *)HWRPB_ADDR;
	c = (struct crb *)((u_int8_t *)r + r->rpb_crb_off);

	prom_dispatch_v.routine_arg = c->crb_v_dispatch;
	prom_dispatch_v.routine = c->crb_v_dispatch->entry_va;
}

int
prom_getenv(id, buf, len)
	int id, len;
	char *buf;
{
	/*
	 * On at least some systems, the GETENV call requires a
	 * 8-byte-aligned buffer, or it bails out with a "kernel stack
	 * not valid halt". Provide a local, aligned buffer here and
	 * then copy to the caller's buffer.
	 */
	static char abuf[128] __attribute__ ((aligned (8)));
	prom_return_t ret;

	ret.bits = prom_dispatch(PROM_R_GETENV, id, (u_int64_t)abuf, 128, 0);
	if (ret.u.status & 0x4)
		ret.u.retval = 0;
	len--;
	if (len > ret.u.retval)
		len = ret.u.retval;
	memcpy(buf, abuf, len);
	buf[len] = '\0';

	return (len);
}