claim.c

linux内核源码

/*
 * Copyright (C) Paul Mackerras 1997.
 * Copyright (C) Leigh Brown 2002.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include "of1275.h"
#include "nonstdio.h"

/*
 * Older OF's require that when claiming a specific range of addresses,
 * we claim the physical space in the /memory node and the virtual
 * space in the chosen mmu node, and then do a map operation to
 * map virtual to physical.
 */
static int need_map = -1;
static ihandle chosen_mmu;
static phandle memory;

/* returns true if s2 is a prefix of s1 */
static int string_match(const char *s1, const char *s2)
{
	for (; *s2; ++s2)
		if (*s1++ != *s2)
			return 0;
	return 1;
}

static int check_of_version(void)
{
	phandle oprom, chosen;
	char version[64];

	oprom = finddevice("/openprom");
	if (oprom == OF_INVALID_HANDLE)
		return 0;
	if (getprop(oprom, "model", version, sizeof(version)) <= 0)
		return 0;
	version[sizeof(version)-1] = 0;
	printf("OF version = '%s'\n", version);
	if (!string_match(version, "Open Firmware, 1.")
	    && !string_match(version, "FirmWorks,3."))
		return 0;
	chosen = finddevice("/chosen");
	if (chosen == OF_INVALID_HANDLE) {
		chosen = finddevice("/chosen@0");
		if (chosen == OF_INVALID_HANDLE) {
			printf("no chosen\n");
			return 0;
		}
	}
	if (getprop(chosen, "mmu", &chosen_mmu, sizeof(chosen_mmu)) <= 0) {
		printf("no mmu\n");
		return 0;
	}
	memory = (ihandle) call_prom("open", 1, 1, "/memory");
	if (memory == OF_INVALID_HANDLE) {
		memory = (ihandle) call_prom("open", 1, 1, "/memory@0");
		if (memory == OF_INVALID_HANDLE) {
			printf("no memory node\n");
			return 0;
		}
	}
	printf("old OF detected\n");
	return 1;
}

void *claim(unsigned int virt, unsigned int size, unsigned int align)
{
	int ret;
	unsigned int result;

	if (need_map < 0)
		need_map = check_of_version();
	if (align || !need_map)
		return (void *) call_prom("claim", 3, 1, virt, size, align);
	
	ret = call_prom_ret("call-method", 5, 2, &result, "claim", memory,
			    align, size, virt);
	if (ret != 0 || result == -1)
		return (void *) -1;
	ret = call_prom_ret("call-method", 5, 2, &result, "claim", chosen_mmu,
			    align, size, virt);
	/* 0x12 == coherent + read/write */
	ret = call_prom("call-method", 6, 1, "map", chosen_mmu,
			0x12, size, virt, virt);
	return virt;
}