xnu-2422.1.72.tar.gz

[apple/xnu.git] / iokit / Kernel / IOSubMemoryDescriptor.cpp

/*
 * Copyright (c) 1998-2007 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The 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,
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 */

#include <IOKit/IOSubMemoryDescriptor.h>

#include "IOKitKernelInternal.h"

#define super IOMemoryDescriptor

OSDefineMetaClassAndStructors(IOSubMemoryDescriptor, IOMemoryDescriptor)

IOReturn IOSubMemoryDescriptor::redirect( task_t safeTask, bool doRedirect )
{
#ifdef __LP64__
    super::redirect( safeTask, doRedirect );
#endif /* __LP64__ */
    return( _parent->redirect( safeTask, doRedirect ));
}

IOSubMemoryDescriptor *
IOSubMemoryDescriptor::withSubRange(IOMemoryDescriptor *	of,
				IOByteCount		offset,
				IOByteCount		length,
				IOOptionBits		options)
{
    IOSubMemoryDescriptor *self = new IOSubMemoryDescriptor;

    if (self && !self->initSubRange(of, offset, length, (IODirection) options)) {
        self->release();
	self = 0;
    }
    return self;
}

bool IOSubMemoryDescriptor::initSubRange( IOMemoryDescriptor * parent,
					IOByteCount offset, IOByteCount length,
					IODirection direction )
{
    if( parent && ((offset + length) > parent->getLength()))
	return( false);

    /*
     * We can check the _parent instance variable before having ever set it
     * to an initial value because I/O Kit guarantees that all our instance
     * variables are zeroed on an object's allocation.
     */

    if( !_parent) {
	if( !super::init())
	    return( false );
    } else {
	/*
	 * An existing memory descriptor is being retargeted to
	 * point to somewhere else.  Clean up our present state.
	 */

	_parent->release();
    }

    if (parent) {
	parent->retain();
	_tag	= parent->getTag();
    }
    else {
        _tag    = 0;
    }
    _parent	= parent;
    _start	= offset;
    _length	= length;
    _flags	= direction;
#ifndef __LP64__
    _direction  = (IODirection) (_flags & kIOMemoryDirectionMask);
#endif /* !__LP64__ */

    return( true );
}

void IOSubMemoryDescriptor::free( void )
{
    if( _parent)
	_parent->release();

    super::free();
}

addr64_t
IOSubMemoryDescriptor::getPhysicalSegment(IOByteCount offset, IOByteCount * length, IOOptionBits options)
{
    addr64_t	address;
    IOByteCount	actualLength;

    assert(offset <= _length);

    if( length)
        *length = 0;

    if( offset >= _length)
        return( 0 );

    address = _parent->getPhysicalSegment( offset + _start, &actualLength, options );

    if( address && length)
	*length = min( _length - offset, actualLength );

    return( address );
}

IOReturn IOSubMemoryDescriptor::setPurgeable( IOOptionBits newState,
                                    IOOptionBits * oldState )
{
    IOReturn err;

    err = _parent->setPurgeable( newState, oldState );

    return( err );
}

IOReturn IOSubMemoryDescriptor::prepare(
		IODirection forDirection)
{
    IOReturn	err;

    err = _parent->prepare( forDirection);

    return( err );
}

IOReturn IOSubMemoryDescriptor::complete(
		IODirection forDirection)
{
    IOReturn	err;

    err = _parent->complete( forDirection);

    return( err );
}

IOMemoryMap * IOSubMemoryDescriptor::makeMapping(
	IOMemoryDescriptor *	owner,
	task_t			intoTask,
	IOVirtualAddress	address,
	IOOptionBits		options,
	IOByteCount		offset,
	IOByteCount		length )
{
    IOMemoryMap * mapping = 0;

#ifndef __LP64__
    if (!(kIOMap64Bit & options))
    {
	panic("IOSubMemoryDescriptor::makeMapping !64bit");
    }
#endif /* !__LP64__ */

    mapping = (IOMemoryMap *) _parent->makeMapping(
					owner,
					intoTask,
					address,
					options, _start + offset, length );

    return( mapping );
}

uint64_t
IOSubMemoryDescriptor::getPreparationID( void )
{
    uint64_t pID;

    if (!super::getKernelReserved())
        return (kIOPreparationIDUnsupported);    

    pID = _parent->getPreparationID();
    if (reserved->kernReserved[0] != pID)
    {
        reserved->kernReserved[0] = pID;
        reserved->preparationID   = kIOPreparationIDUnprepared;
        super::setPreparationID();
    }

    return (super::getPreparationID());    
}