xref: /src/sys/arch/dreamcast/dev/g2/g2bus_bus_mem.c

/*	$NetBSD: g2bus_bus_mem.c,v 1.2 2001/01/31 21:58:37 marcus Exp $	*/

/*-
 * Copyright (c) 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Bus space implementation for the SEGA G2 bus.
 *
 * NOTE: We only implement a small subset of what the bus_space(9)
 * API specifies.  Right now, the GAPS PCI bridge is only used for
 * the Dreamcast Broadband Adatper, so we only provide what the
 * pci(4) and rtk(4) drivers need.
 */

#include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <machine/cpu.h>
#include <machine/bus.h>
#include <machine/cpufunc.h>

#include <dreamcast/dev/g2/g2busvar.h>

int	g2bus_bus_mem_map(void *, bus_addr_t, bus_size_t, int,
	    bus_space_handle_t *);
void	g2bus_bus_mem_unmap(void *, bus_space_handle_t, bus_size_t);

u_int8_t g2bus_bus_mem_read_1(void *, bus_space_handle_t, bus_size_t);
u_int16_t g2bus_bus_mem_read_2(void *, bus_space_handle_t, bus_size_t);
u_int32_t g2bus_bus_mem_read_4(void *, bus_space_handle_t, bus_size_t);

void	g2bus_bus_mem_write_1(void *, bus_space_handle_t, bus_size_t,
	    u_int8_t);
void	g2bus_bus_mem_write_2(void *, bus_space_handle_t, bus_size_t,
	    u_int16_t);
void	g2bus_bus_mem_write_4(void *, bus_space_handle_t, bus_size_t,
	    u_int32_t);

void
g2bus_bus_mem_init(struct g2bus_softc *sc)
{
	bus_space_tag_t t = &sc->sc_memt;

	memset(t, 0, sizeof(*t));

	t->dbs_map = g2bus_bus_mem_map;
	t->dbs_unmap = g2bus_bus_mem_unmap;

	t->dbs_r_1 = g2bus_bus_mem_read_1;
	t->dbs_r_2 = g2bus_bus_mem_read_2;
	t->dbs_r_4 = g2bus_bus_mem_read_4;

	t->dbs_w_1 = g2bus_bus_mem_write_1;
	t->dbs_w_2 = g2bus_bus_mem_write_2;
	t->dbs_w_4 = g2bus_bus_mem_write_4;
}

int
g2bus_bus_mem_map(void *v, bus_addr_t addr, bus_size_t size, int flags,
    bus_space_handle_t *shp)
{

	KASSERT((addr & SH3_PHYS_MASK) == addr);
	*shp = SH3_PHYS_TO_P2SEG(addr);

	return (0);
}

void
g2bus_bus_mem_unmap(void *v, bus_space_handle_t sh, bus_size_t size)
{

	KASSERT(sh >= SH3_P2SEG_BASE && sh <= SH3_P2SEG_END);
	/* Nothing to do. */
}

/*
 * G2 bus cycles must not be interrupted by IRQs or G2 DMA.
 * The following paired macros will take the necessary precautions.
 */

#define G2_LOCK								\
	do {								\
		disable_intr();						\
		/* suspend any G2 DMA here... */			\
		while((*(volatile unsigned int *)0xa05f688c) & 32);	\
	} while(0)

#define G2_UNLOCK							\
	do {								\
		/* resume any G2 DMA here... */				\
		enable_intr();						\
	} while(0)


u_int8_t
g2bus_bus_mem_read_1(void *v, bus_space_handle_t sh, bus_size_t off)
{
	u_int8_t rv;

	G2_LOCK;

	rv = *(u_int8_t *)(sh + off);

	G2_UNLOCK;

	return (rv);
}

u_int16_t
g2bus_bus_mem_read_2(void *v, bus_space_handle_t sh, bus_size_t off)
{
	u_int16_t rv;

	G2_LOCK;

	rv = *(u_int16_t *)(sh + off);

	G2_UNLOCK;

	return (rv);
}

u_int32_t
g2bus_bus_mem_read_4(void *v, bus_space_handle_t sh, bus_size_t off)
{
	u_int32_t rv;

	G2_LOCK;

	rv = *(u_int32_t *)(sh + off);

	G2_UNLOCK;

	return (rv);
}

void
g2bus_bus_mem_write_1(void *v, bus_space_handle_t sh, bus_size_t off,
    u_int8_t val)
{

	G2_LOCK;

	*(u_int8_t *)(sh + off) = val;

	G2_UNLOCK;
}

void
g2bus_bus_mem_write_2(void *v, bus_space_handle_t sh, bus_size_t off,
    u_int16_t val)
{

	G2_LOCK;

	*(u_int16_t *)(sh + off) = val;

	G2_UNLOCK;
}

void
g2bus_bus_mem_write_4(void *v, bus_space_handle_t sh, bus_size_t off,
    u_int32_t val)
{

	G2_LOCK;

	*(u_int32_t *)(sh + off) = val;

	G2_UNLOCK;
}