Source to osfmk/ppc/io_map.c


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/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @[email protected]
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @[email protected]
 */
/*
 * @[email protected]
 * 
 */

#include <debug.h>
#include <mach/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <ppc/pmap.h>
#include <ppc/io_map_entries.h>
#include <ppc/Firmware.h>
#include <ppc/mappings.h>

extern vm_offset_t	virtual_avail;

/*
 * Allocate and map memory for devices that may need to be mapped 
 * outside the usual physical memory. If phys_addr is NULL then
 * steal the appropriate number of physical pages from the vm
 * system and map them.
 */
vm_offset_t
io_map(phys_addr, size)
	vm_offset_t	phys_addr;
	vm_size_t	size;
{
	vm_offset_t	start;
	int		i;
	unsigned int j;
	vm_page_t 	m;


#if DEBUG
	assert (kernel_map != VM_MAP_NULL);			/* VM must be initialised */
#endif
	
	mapping_prealloc(size);						/* TEMPORARY - make sure there are enough free mappings */

	if (phys_addr != 0) {
		/* make sure we map full contents of all the pages concerned */
		size = round_page(size + (phys_addr & PAGE_MASK));

		/* Steal some free virtual addresses */

		(void) kmem_alloc_pageable(kernel_map, &start, size);
	
		(void) pmap_map_bd(start,
				   trunc_page(phys_addr),
				   trunc_page(phys_addr) + size,
				   VM_PROT_READ|VM_PROT_WRITE);

		mapping_relpre();						/* TEMPORARY - Allow mapping release */
		return (start + (phys_addr & PAGE_MASK));
	
	} else {
		/* Steal some free virtual addresses */
		(void) kmem_alloc_pageable(kernel_map, &start, size);

		/* Steal some physical pages and map them one by one */
		for (i = 0; i < size ; i += PAGE_SIZE) {
			m = VM_PAGE_NULL;
			while ((m = vm_page_grab()) == VM_PAGE_NULL)
				VM_PAGE_WAIT();
			vm_page_gobble(m);
			(void) pmap_map_bd(start + i,
					   m->phys_addr,
					   m->phys_addr + PAGE_SIZE,
					   VM_PROT_READ|VM_PROT_WRITE);
		}

		mapping_relpre();						/* TEMPORARY - Allow mapping release */
		return start;
	}
}