xref: /netbsd-src/sys/arch/arm/include/bus_defs.h (revision 5158b98c3ad5629f6fdc5db5d57b396373690489)

/*	$NetBSD: bus_defs.h,v 1.19 2022/10/15 11:07:38 jmcneill Exp $	*/

/*-
 * Copyright (c) 1996, 1997, 1998, 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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.
 *
 * 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.
 */

/*
 * Copyright (c) 1996 Charles M. Hannum.  All rights reserved.
 * Copyright (c) 1996 Christopher G. Demetriou.  All rights reserved.
 *
 * 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 Christopher G. Demetriou
 *	for the NetBSD Project.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#ifndef _ARM_BUS_DEFS_H_
#define _ARM_BUS_DEFS_H_

#if defined(_KERNEL_OPT)
#include "opt_arm_bus_space.h"
#include "opt_kasan.h"
#endif

/*
 * Addresses (in bus space).
 */
typedef u_long bus_addr_t;
typedef u_long bus_size_t;

#define	PRIxBUSADDR	"lx"
#define	PRIxBUSSIZE	"lx"
#define	PRIuBUSSIZE	"lu"

/*
 * Access methods for bus space.
 */
typedef struct bus_space *bus_space_tag_t;
typedef u_long bus_space_handle_t;

#define	PRIxBSH		"lx"

/*
 *	int bus_space_map(bus_space_tag_t t, bus_addr_t addr,
 *	    bus_size_t size, int flags, bus_space_handle_t *bshp);
 *
 * Map a region of bus space.
 */

#define	BUS_SPACE_MAP_CACHEABLE		0x01
#define	BUS_SPACE_MAP_LINEAR		0x02
#define	BUS_SPACE_MAP_PREFETCHABLE     	0x04

#define	BUS_SPACE_MAP_BUS1		0x0100
#define	BUS_SPACE_MAP_BUS2		0x0200
#define	BUS_SPACE_MAP_BUS3		0x0400
#define	BUS_SPACE_MAP_BUS4		0x0800

#define	BUS_SPACE_MAP_NONPOSTED		BUS_SPACE_MAP_BUS1

struct bus_space {
	/* cookie */
	void		*bs_cookie;

	/* used for aarch64. require ".bs_cookie = bus_space" */
	int		bs_stride;	/* offset <<= bs_stride (if needed) */
	int		bs_flags;

	/* mapping/unmapping */
	int		(*bs_map)(void *, bus_addr_t, bus_size_t,
			    int, bus_space_handle_t *);
	void		(*bs_unmap)(void *, bus_space_handle_t,
			    bus_size_t);
	int		(*bs_subregion)(void *, bus_space_handle_t,
			    bus_size_t, bus_size_t, bus_space_handle_t *);

	/* allocation/deallocation */
	int		(*bs_alloc)(void *, bus_addr_t, bus_addr_t,
			    bus_size_t, bus_size_t, bus_size_t, int,
			    bus_addr_t *, bus_space_handle_t *);
	void		(*bs_free)(void *, bus_space_handle_t,
			    bus_size_t);

	/* get kernel virtual address */
	void *		(*bs_vaddr)(void *, bus_space_handle_t);

	/* mmap bus space for user */
	paddr_t		(*bs_mmap)(void *, bus_addr_t, off_t, int, int);

	/* barrier */
	void		(*bs_barrier)(void *, bus_space_handle_t,
			    bus_size_t, bus_size_t, int);

	/* read (single) */
	uint8_t		(*bs_r_1)(void *, bus_space_handle_t,
			    bus_size_t);
	uint16_t	(*bs_r_2)(void *, bus_space_handle_t,
			    bus_size_t);
	uint32_t	(*bs_r_4)(void *, bus_space_handle_t,
			    bus_size_t);
	uint64_t	(*bs_r_8)(void *, bus_space_handle_t,
			    bus_size_t);

	/* read multiple */
	void		(*bs_rm_1)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t *, bus_size_t);
	void		(*bs_rm_2)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t *, bus_size_t);
	void		(*bs_rm_4)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t *, bus_size_t);
	void		(*bs_rm_8)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t *, bus_size_t);

	/* read region */
	void		(*bs_rr_1)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t *, bus_size_t);
	void		(*bs_rr_2)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t *, bus_size_t);
	void		(*bs_rr_4)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t *, bus_size_t);
	void		(*bs_rr_8)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t *, bus_size_t);

	/* write (single) */
	void		(*bs_w_1)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t);
	void		(*bs_w_2)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t);
	void		(*bs_w_4)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t);
	void		(*bs_w_8)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t);

	/* write multiple */
	void		(*bs_wm_1)(void *, bus_space_handle_t,
			    bus_size_t, const uint8_t *, bus_size_t);
	void		(*bs_wm_2)(void *, bus_space_handle_t,
			    bus_size_t, const uint16_t *, bus_size_t);
	void		(*bs_wm_4)(void *, bus_space_handle_t,
			    bus_size_t, const uint32_t *, bus_size_t);
	void		(*bs_wm_8)(void *, bus_space_handle_t,
			    bus_size_t, const uint64_t *, bus_size_t);

	/* write region */
	void		(*bs_wr_1)(void *, bus_space_handle_t,
			    bus_size_t, const uint8_t *, bus_size_t);
	void		(*bs_wr_2)(void *, bus_space_handle_t,
			    bus_size_t, const uint16_t *, bus_size_t);
	void		(*bs_wr_4)(void *, bus_space_handle_t,
			    bus_size_t, const uint32_t *, bus_size_t);
	void		(*bs_wr_8)(void *, bus_space_handle_t,
			    bus_size_t, const uint64_t *, bus_size_t);

	/* set multiple */
	void		(*bs_sm_1)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t, bus_size_t);
	void		(*bs_sm_2)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t, bus_size_t);
	void		(*bs_sm_4)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t, bus_size_t);
	void		(*bs_sm_8)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t, bus_size_t);

	/* set region */
	void		(*bs_sr_1)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t, bus_size_t);
	void		(*bs_sr_2)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t, bus_size_t);
	void		(*bs_sr_4)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t, bus_size_t);
	void		(*bs_sr_8)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t, bus_size_t);

	/* copy */
	void		(*bs_c_1)(void *, bus_space_handle_t, bus_size_t,
			    bus_space_handle_t, bus_size_t, bus_size_t);
	void		(*bs_c_2)(void *, bus_space_handle_t, bus_size_t,
			    bus_space_handle_t, bus_size_t, bus_size_t);
	void		(*bs_c_4)(void *, bus_space_handle_t, bus_size_t,
			    bus_space_handle_t, bus_size_t, bus_size_t);
	void		(*bs_c_8)(void *, bus_space_handle_t, bus_size_t,
			    bus_space_handle_t, bus_size_t, bus_size_t);

#ifdef __BUS_SPACE_HAS_STREAM_METHODS
	/* read stream (single) */
	uint8_t		(*bs_r_1_s)(void *, bus_space_handle_t,
			    bus_size_t);
	uint16_t	(*bs_r_2_s)(void *, bus_space_handle_t,
			    bus_size_t);
	uint32_t	(*bs_r_4_s)(void *, bus_space_handle_t,
			    bus_size_t);
	uint64_t	(*bs_r_8_s)(void *, bus_space_handle_t,
			    bus_size_t);

	/* read multiple stream */
	void		(*bs_rm_1_s)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t *, bus_size_t);
	void		(*bs_rm_2_s)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t *, bus_size_t);
	void		(*bs_rm_4_s)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t *, bus_size_t);
	void		(*bs_rm_8_s)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t *, bus_size_t);

	/* read region stream */
	void		(*bs_rr_1_s)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t *, bus_size_t);
	void		(*bs_rr_2_s)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t *, bus_size_t);
	void		(*bs_rr_4_s)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t *, bus_size_t);
	void		(*bs_rr_8_s)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t *, bus_size_t);

	/* write stream (single) */
	void		(*bs_w_1_s)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t);
	void		(*bs_w_2_s)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t);
	void		(*bs_w_4_s)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t);
	void		(*bs_w_8_s)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t);

	/* write multiple stream */
	void		(*bs_wm_1_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint8_t *, bus_size_t);
	void		(*bs_wm_2_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint16_t *, bus_size_t);
	void		(*bs_wm_4_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint32_t *, bus_size_t);
	void		(*bs_wm_8_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint64_t *, bus_size_t);

	/* write region stream */
	void		(*bs_wr_1_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint8_t *, bus_size_t);
	void		(*bs_wr_2_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint16_t *, bus_size_t);
	void		(*bs_wr_4_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint32_t *, bus_size_t);
	void		(*bs_wr_8_s)(void *, bus_space_handle_t,
			    bus_size_t, const uint64_t *, bus_size_t);
#endif	/* __BUS_SPACE_HAS_STREAM_METHODS */

#ifdef __BUS_SPACE_HAS_PROBING_METHODS
	/* peek */
	int		(*bs_pe_1)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t *);
	int		(*bs_pe_2)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t *);
	int		(*bs_pe_4)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t *);
	int		(*bs_pe_8)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t *);

	/* poke */
	int		(*bs_po_1)(void *, bus_space_handle_t,
			    bus_size_t, uint8_t);
	int		(*bs_po_2)(void *, bus_space_handle_t,
			    bus_size_t, uint16_t);
	int		(*bs_po_4)(void *, bus_space_handle_t,
			    bus_size_t, uint32_t);
	int		(*bs_po_8)(void *, bus_space_handle_t,
			    bus_size_t, uint64_t);
#endif /* __BUS_SPACE_HAS_PROBING_METHODS */
};

#define	BUS_SPACE_BARRIER_READ	0x01
#define	BUS_SPACE_BARRIER_WRITE	0x02

#define BUS_SPACE_ALIGNED_POINTER(p, t) ALIGNED_POINTER(p, t)

/* Bus Space DMA macros */

/*
 * Flags used in various bus DMA methods.
 */
#define	BUS_DMA_WAITOK		0x000	/* safe to sleep (pseudo-flag) */
#define	BUS_DMA_NOWAIT		0x001	/* not safe to sleep */
#define	BUS_DMA_ALLOCNOW	0x002	/* perform resource allocation now */
#define	BUS_DMA_COHERENT	0x004	/* hint: map memory DMA coherent */
#define	BUS_DMA_STREAMING	0x008	/* hint: sequential, unidirectional */
#define	BUS_DMA_BUS1		0x010	/* placeholders for bus functions... */
#define	BUS_DMA_BUS2		0x020
#define	BUS_DMA_BUS3		0x040
#define	BUS_DMA_BUS4		0x080
#define	BUS_DMA_READ		0x100	/* mapping is device -> memory only */
#define	BUS_DMA_WRITE		0x200	/* mapping is memory -> device only */
#define	BUS_DMA_NOCACHE		0x400	/* hint: map non-cached memory */

/*
 * Private flags stored in the DMA map.
 */
#define	_BUS_DMAMAP_COHERENT	0x10000	/* no cache flush necessary on sync */
#define	_BUS_DMAMAP_IS_BOUNCING	0x20000 /* is bouncing current xfer */
#define	_BUS_DMAMAP_NOALLOC	0x40000	/* don't alloc memory from this range */

/* Forwards needed by prototypes below. */
struct mbuf;
struct uio;

/*
 * Operations performed by bus_dmamap_sync().
 */
#define	BUS_DMASYNC_PREREAD	0x01	/* pre-read synchronization */
#define	BUS_DMASYNC_POSTREAD	0x02	/* post-read synchronization */
#define	BUS_DMASYNC_PREWRITE	0x04	/* pre-write synchronization */
#define	BUS_DMASYNC_POSTWRITE	0x08	/* post-write synchronization */

typedef struct arm32_bus_dma_tag	*bus_dma_tag_t;
typedef struct arm32_bus_dmamap		*bus_dmamap_t;

#define BUS_DMA_TAG_VALID(t)    ((t) != (bus_dma_tag_t)0)

/*
 *	bus_dma_segment_t
 *
 *	Describes a single contiguous DMA transaction.  Values
 *	are suitable for programming into DMA registers.
 */
struct arm32_bus_dma_segment {
	/*
	 * PUBLIC MEMBERS: these are used by machine-independent code.
	 */
	bus_addr_t	ds_addr;	/* DMA address */
	bus_size_t	ds_len;		/* length of transfer */

	/*
	 * PRIVATE MEMBERS:
	 */
	uint32_t	_ds_flags;	/* _BUS_DMAMAP_COHERENT */
	paddr_t		_ds_paddr;	/* CPU address */
};
typedef struct arm32_bus_dma_segment	bus_dma_segment_t;

/*
 *	arm32_dma_range
 *
 *	This structure describes a valid DMA range.
 */
struct arm32_dma_range {
	bus_addr_t	dr_sysbase;	/* system base address */
	bus_addr_t	dr_busbase;	/* appears here on bus */
	bus_size_t	dr_len;		/* length of range */
	uint32_t	dr_flags;	/* flags for range */
};

/*
 *	bus_dma_tag_t
 *
 *	A machine-dependent opaque type describing the implementation of
 *	DMA for a given bus.
 */

struct arm32_bus_dma_tag {
	/*
	 * DMA range for this tag.  If the page doesn't fall within
	 * one of these ranges, an error is returned.  The caller
	 * may then decide what to do with the transfer.  If the
	 * range pointer is NULL, it is ignored.
	 */
	struct arm32_dma_range *_ranges;
	int _nranges;

	/*
	 * Opaque cookie for use by back-end.
	 */
	void *_cookie;

	/*
	 * DMA mapping methods.
	 */
	int	(*_dmamap_create)(bus_dma_tag_t, bus_size_t, int,
		    bus_size_t, bus_size_t, int, bus_dmamap_t *);
	void	(*_dmamap_destroy)(bus_dma_tag_t, bus_dmamap_t);
	int	(*_dmamap_load)(bus_dma_tag_t, bus_dmamap_t, void *,
		    bus_size_t, struct proc *, int);
	int	(*_dmamap_load_mbuf)(bus_dma_tag_t, bus_dmamap_t,
		    struct mbuf *, int);
	int	(*_dmamap_load_uio)(bus_dma_tag_t, bus_dmamap_t,
		    struct uio *, int);
	int	(*_dmamap_load_raw)(bus_dma_tag_t, bus_dmamap_t,
		    bus_dma_segment_t *, int, bus_size_t, int);
	void	(*_dmamap_unload)(bus_dma_tag_t, bus_dmamap_t);
	void	(*_dmamap_sync_pre)(bus_dma_tag_t, bus_dmamap_t,
		    bus_addr_t, bus_size_t, int);
	void	(*_dmamap_sync_post)(bus_dma_tag_t, bus_dmamap_t,
		    bus_addr_t, bus_size_t, int);

	/*
	 * DMA memory utility functions.
	 */
	int	(*_dmamem_alloc)(bus_dma_tag_t, bus_size_t, bus_size_t,
		    bus_size_t, bus_dma_segment_t *, int, int *, int);
	void	(*_dmamem_free)(bus_dma_tag_t,
		    bus_dma_segment_t *, int);
	int	(*_dmamem_map)(bus_dma_tag_t, bus_dma_segment_t *,
		    int, size_t, void **, int);
	void	(*_dmamem_unmap)(bus_dma_tag_t, void *, size_t);
	paddr_t	(*_dmamem_mmap)(bus_dma_tag_t, bus_dma_segment_t *,
		    int, off_t, int, int);

	/*
	 * DMA tag utility functions
	 */
	int	(*_dmatag_subregion)(bus_dma_tag_t, bus_addr_t, bus_addr_t,
		     bus_dma_tag_t *, int);
	void	(*_dmatag_destroy)(bus_dma_tag_t);

	/*
	 * State for bounce buffers
	 */
	int	_tag_needs_free;
	int	(*_may_bounce)(bus_dma_tag_t, bus_dmamap_t, int, int *);
};

/*
 *	bus_dmamap_t
 *
 *	Describes a DMA mapping.
 */
struct arm32_bus_dmamap {
	/*
	 * PRIVATE MEMBERS: not for use by machine-independent code.
	 */
	bus_size_t	_dm_size;	/* largest DMA transfer mappable */
	int		_dm_segcnt;	/* number of segs this map can map */
	bus_size_t	_dm_maxmaxsegsz; /* fixed largest possible segment */
	bus_size_t	_dm_boundary;	/* don't cross this */
	int		_dm_flags;	/* misc. flags */

	void		*_dm_origbuf;	/* pointer to original buffer */
	int		_dm_buftype;	/* type of buffer */
	struct vmspace	*_dm_vmspace;	/* vmspace that owns the mapping */

	void		*_dm_cookie;	/* cookie for bus-specific functions */
	void		*_dm_iommu;	/* cookie for iommu functions */

	/*
	 * PUBLIC MEMBERS: these are used by machine-independent code.
	 */
#if defined(KASAN)
	void		*dm_buf;
	bus_size_t	dm_buflen;
	int		dm_buftype;
#endif
	bus_size_t	dm_maxsegsz;	/* largest possible segment */
	bus_size_t	dm_mapsize;	/* size of the mapping */
	int		dm_nsegs;	/* # valid segments in mapping */
	bus_dma_segment_t dm_segs[1];	/* segments; variable length */
};

/* _dm_buftype */
#define	_BUS_DMA_BUFTYPE_INVALID	0
#define	_BUS_DMA_BUFTYPE_LINEAR		1
#define	_BUS_DMA_BUFTYPE_MBUF		2
#define	_BUS_DMA_BUFTYPE_UIO		3
#define	_BUS_DMA_BUFTYPE_RAW		4

#ifdef _ARM32_BUS_DMA_PRIVATE
#define	_BUS_AVAIL_END	(physical_end - 1)
/*
 * Cookie used for bounce buffers. A pointer to one of these it stashed in
 * the DMA map.
 */
struct arm32_bus_dma_cookie {
	int	id_flags;		/* flags; see below */

	/*
	 * Information about the original buffer used during
	 * DMA map syncs.  Note that origibuflen is only used
	 * for ID_BUFTYPE_LINEAR.
	 */
	union {
		void	*un_origbuf;		/* pointer to orig buffer if
						   bouncing */
		char	*un_linearbuf;
		struct mbuf	*un_mbuf;
		struct uio	*un_uio;
	} id_origbuf_un;
#define	id_origbuf		id_origbuf_un.un_origbuf
#define	id_origlinearbuf	id_origbuf_un.un_linearbuf
#define	id_origmbuf		id_origbuf_un.un_mbuf
#define	id_origuio		id_origbuf_un.un_uio
	bus_size_t id_origbuflen;	/* ...and size */

	void	*id_bouncebuf;		/* pointer to the bounce buffer */
	bus_size_t id_bouncebuflen;	/* ...and size */
	int	id_nbouncesegs;		/* number of valid bounce segs */
	bus_dma_segment_t id_bouncesegs[0]; /* array of bounce buffer
					       physical memory segments */
};

/* id_flags */
#define	_BUS_DMA_IS_BOUNCING		0x04	/* is bouncing current xfer */
#define	_BUS_DMA_HAS_BOUNCE		0x02	/* has bounce buffers */
#endif /* _ARM32_BUS_DMA_PRIVATE */
#define	_BUS_DMA_MIGHT_NEED_BOUNCE	0x01	/* may need bounce buffers */

#endif /* _ARM_BUS_DEFS_H_ */