/*      $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);
}