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ioexpand.h
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ioexpand.h
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/*
* Copyright 2009 by Brian Dominy <[email protected]>
*
* This file is part of GCC6809.
*
* GCC6809 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.
*
* GCC6809 is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GCC6809; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef IOEXPAND_H
#define IOEXPAND_H
/* An I/O expander subdivides a single, 128-byte region into 16, 8-byte slots
each of which can hold a device. It is needed to work around the inability
of the system bus to handle attaching devices less than 128 bytes in size.
When mapping a slot, an offset can be applied to the underlying device. An
example application is to make the I/O expander occupy fewer than 128 bytes
by mapping one or more slots to a large underlying ROM.
*/
#define NR_IOEXPAND 16
#define IO_WINDOW 8
struct ioexpand
{
struct hw_device *ios[NR_IOEXPAND];
unsigned long offset[NR_IOEXPAND];
};
struct hw_device *ioexpand_create (void);
void ioexpand_attach (struct hw_device *expander_dev, int slot, unsigned long offset, struct hw_device *io_dev);
void ioexpand_reset (struct hw_device *dev);
U8 ioexpand_read (struct hw_device *dev, unsigned long addr);
void ioexpand_write (struct hw_device *dev, unsigned long addr, U8 val);
struct hw_device *ioexpand_create (void);
#endif