/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright 2019 Peter Tribble.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/promif.h>
#include <sys/prom_plat.h>
#include <sys/salib.h>

extern int is_sun4v;

/*
 * Retain a page or reclaim a previously retained page of physical
 * memory for use by the prom upgrade. If successful, leave
 * an indication that a page was retained by creating a boolean
 * property in the root node.
 *
 * XXX: SUNW,retain doesn't work as expected on server systems,
 * so we don't try to retain any memory on those systems.
 *
 * XXX: do a '0 to my-self' as a workaround for 4160914
 */

int dont_retain_memory;

void
retain_nvram_page(void)
{
        unsigned long long phys = 0;
        int len;
        char name[32];
        static char create_prop[] =
            "0 to my-self dev / 0 0 \" boot-retained-page\" property";
        static char ue[] = "SUNW,Ultra-Enterprise";
        extern int verbosemode;

        if (dont_retain_memory)
                return;

        if (!is_sun4v) {
                len = prom_getproplen(prom_rootnode(), "name");
                if ((len != -1) && (len <= sizeof (name))) {
                        (void) prom_getprop(prom_rootnode(), "name", name);
                        if (strcmp(name, ue) == 0)
                                return;
                }
        }

        if (prom_retain("OBPnvram", PAGESIZE, PAGESIZE, &phys) != 0) {
                printf("prom_retain failed\n");
                return;
        }
        if (verbosemode)
                printf("retained OBPnvram page at 0x%llx\n", phys);

        prom_interpret(create_prop, 0, 0, 0, 0, 0);
}