xref: /netbsd-src/sys/arch/riscv/include/bus_defs.h (revision 4f645668ed707e1f969c546666f8c8e45e6f8888)
1 /*	$NetBSD: bus_defs.h,v 1.2 2022/11/19 12:16:03 skrll Exp $	*/
2 
3 /*-
4  * Copyright (c) 1996, 1997, 1998, 2001 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /*
34  * Copyright (c) 1996 Charles M. Hannum.  All rights reserved.
35  * Copyright (c) 1996 Christopher G. Demetriou.  All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  * 3. All advertising materials mentioning features or use of this software
46  *    must display the following acknowledgement:
47  *      This product includes software developed by Christopher G. Demetriou
48  *	for the NetBSD Project.
49  * 4. The name of the author may not be used to endorse or promote products
50  *    derived from this software without specific prior written permission
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
53  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
54  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
55  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
56  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
57  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
58  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
59  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
60  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
61  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
62  */
63 
64 #ifndef _RISCV_BUS_DEFS_H_
65 #define _RISCV_BUS_DEFS_H_
66 
67 /*
68  * Addresses (in bus space).
69  */
70 typedef paddr_t bus_addr_t;
71 typedef psize_t bus_size_t;
72 
73 #define PRIxBUSADDR	PRIxPADDR
74 #define PRIxBUSSIZE	PRIxPSIZE
75 #define PRIuBUSSIZE	PRIuPSIZE
76 
77 typedef struct bus_space *bus_space_tag_t;
78 typedef uintptr_t bus_space_handle_t;
79 
80 #define PRIxBSH		PRIxPTR
81 
82 /*
83  *	int bus_space_map(bus_space_tag_t t, bus_addr_t addr,
84  *	    bus_size_t size, int flags, bus_space_handle_t *bshp);
85  *
86  * Map a region of bus space.
87  */
88 #define	BUS_SPACE_MAP_BUS1		__BIT(8)
89 #define	BUS_SPACE_MAP_BUS2		__BIT(9)
90 #define	BUS_SPACE_MAP_BUS3		__BIT(10)
91 #define	BUS_SPACE_MAP_BUS4		__BIT(11)
92 
93 struct bus_space {
94 	int		bs_stride;	/* offset <<= bs_stride (if needed) */
95 
96 	/* mapping/unmapping */
97 	int		(*bs_map)(void *, bus_addr_t, bus_size_t,
98 			    int, bus_space_handle_t *);
99 	void		(*bs_unmap)(void *, bus_space_handle_t,
100 			    bus_size_t);
101 	int		(*bs_subregion)(void *, bus_space_handle_t,
102 			    bus_size_t, bus_size_t, bus_space_handle_t *);
103 
104 	/* allocation/deallocation */
105 	int		(*bs_alloc)(void *, bus_addr_t, bus_addr_t,
106 			    bus_size_t, bus_size_t, bus_size_t, int,
107 			    bus_addr_t *, bus_space_handle_t *);
108 	void		(*bs_free)(void *, bus_space_handle_t,
109 			    bus_size_t);
110 
111 	/* get kernel virtual address */
112 	void *		(*bs_vaddr)(void *, bus_space_handle_t);
113 
114 	/* mmap bus space for user */
115 	paddr_t		(*bs_mmap)(void *, bus_addr_t, off_t, int, int);
116 
117 	/* barrier */
118 	void		(*bs_barrier)(void *, bus_space_handle_t,
119 			    bus_size_t, bus_size_t, int);
120 
121 	/* read (single) */
122 	uint8_t		(*bs_r_1)(void *, bus_space_handle_t,
123 			    bus_size_t);
124 	uint16_t	(*bs_r_2)(void *, bus_space_handle_t,
125 			    bus_size_t);
126 	uint32_t	(*bs_r_4)(void *, bus_space_handle_t,
127 			    bus_size_t);
128 	uint64_t	(*bs_r_8)(void *, bus_space_handle_t,
129 			    bus_size_t);
130 
131 	/* read multiple */
132 	void		(*bs_rm_1)(void *, bus_space_handle_t,
133 			    bus_size_t, uint8_t *, bus_size_t);
134 	void		(*bs_rm_2)(void *, bus_space_handle_t,
135 			    bus_size_t, uint16_t *, bus_size_t);
136 	void		(*bs_rm_4)(void *, bus_space_handle_t,
137 			    bus_size_t, uint32_t *, bus_size_t);
138 	void		(*bs_rm_8)(void *, bus_space_handle_t,
139 			    bus_size_t, uint64_t *, bus_size_t);
140 
141 	/* read region */
142 	void		(*bs_rr_1)(void *, bus_space_handle_t,
143 			    bus_size_t, uint8_t *, bus_size_t);
144 	void		(*bs_rr_2)(void *, bus_space_handle_t,
145 			    bus_size_t, uint16_t *, bus_size_t);
146 	void		(*bs_rr_4)(void *, bus_space_handle_t,
147 			    bus_size_t, uint32_t *, bus_size_t);
148 	void		(*bs_rr_8)(void *, bus_space_handle_t,
149 			    bus_size_t, uint64_t *, bus_size_t);
150 
151 	/* write (single) */
152 	void		(*bs_w_1)(void *, bus_space_handle_t,
153 			    bus_size_t, uint8_t);
154 	void		(*bs_w_2)(void *, bus_space_handle_t,
155 			    bus_size_t, uint16_t);
156 	void		(*bs_w_4)(void *, bus_space_handle_t,
157 			    bus_size_t, uint32_t);
158 	void		(*bs_w_8)(void *, bus_space_handle_t,
159 			    bus_size_t, uint64_t);
160 
161 	/* write multiple */
162 	void		(*bs_wm_1)(void *, bus_space_handle_t,
163 			    bus_size_t, const uint8_t *, bus_size_t);
164 	void		(*bs_wm_2)(void *, bus_space_handle_t,
165 			    bus_size_t, const uint16_t *, bus_size_t);
166 	void		(*bs_wm_4)(void *, bus_space_handle_t,
167 			    bus_size_t, const uint32_t *, bus_size_t);
168 	void		(*bs_wm_8)(void *, bus_space_handle_t,
169 			    bus_size_t, const uint64_t *, bus_size_t);
170 
171 	/* write region */
172 	void		(*bs_wr_1)(void *, bus_space_handle_t,
173 			    bus_size_t, const uint8_t *, bus_size_t);
174 	void		(*bs_wr_2)(void *, bus_space_handle_t,
175 			    bus_size_t, const uint16_t *, bus_size_t);
176 	void		(*bs_wr_4)(void *, bus_space_handle_t,
177 			    bus_size_t, const uint32_t *, bus_size_t);
178 	void		(*bs_wr_8)(void *, bus_space_handle_t,
179 			    bus_size_t, const uint64_t *, bus_size_t);
180 
181 	/* set multiple */
182 	void		(*bs_sm_1)(void *, bus_space_handle_t,
183 			    bus_size_t, uint8_t, bus_size_t);
184 	void		(*bs_sm_2)(void *, bus_space_handle_t,
185 			    bus_size_t, uint16_t, bus_size_t);
186 	void		(*bs_sm_4)(void *, bus_space_handle_t,
187 			    bus_size_t, uint32_t, bus_size_t);
188 	void		(*bs_sm_8)(void *, bus_space_handle_t,
189 			    bus_size_t, uint64_t, bus_size_t);
190 
191 	/* set region */
192 	void		(*bs_sr_1)(void *, bus_space_handle_t,
193 			    bus_size_t, uint8_t, bus_size_t);
194 	void		(*bs_sr_2)(void *, bus_space_handle_t,
195 			    bus_size_t, uint16_t, bus_size_t);
196 	void		(*bs_sr_4)(void *, bus_space_handle_t,
197 			    bus_size_t, uint32_t, bus_size_t);
198 	void		(*bs_sr_8)(void *, bus_space_handle_t,
199 			    bus_size_t, uint64_t, bus_size_t);
200 
201 	/* copy */
202 	void		(*bs_c_1)(void *, bus_space_handle_t, bus_size_t,
203 			    bus_space_handle_t, bus_size_t, bus_size_t);
204 	void		(*bs_c_2)(void *, bus_space_handle_t, bus_size_t,
205 			    bus_space_handle_t, bus_size_t, bus_size_t);
206 	void		(*bs_c_4)(void *, bus_space_handle_t, bus_size_t,
207 			    bus_space_handle_t, bus_size_t, bus_size_t);
208 	void		(*bs_c_8)(void *, bus_space_handle_t, bus_size_t,
209 			    bus_space_handle_t, bus_size_t, bus_size_t);
210 
211 #ifdef __BUS_SPACE_HAS_STREAM_METHODS
212 	/* read stream (single) */
213 	uint8_t		(*bs_r_1_s)(void *, bus_space_handle_t,
214 			    bus_size_t);
215 	uint16_t	(*bs_r_2_s)(void *, bus_space_handle_t,
216 			    bus_size_t);
217 	uint32_t	(*bs_r_4_s)(void *, bus_space_handle_t,
218 			    bus_size_t);
219 	uint64_t	(*bs_r_8_s)(void *, bus_space_handle_t,
220 			    bus_size_t);
221 
222 	/* read multiple stream */
223 	void		(*bs_rm_1_s)(void *, bus_space_handle_t,
224 			    bus_size_t, uint8_t *, bus_size_t);
225 	void		(*bs_rm_2_s)(void *, bus_space_handle_t,
226 			    bus_size_t, uint16_t *, bus_size_t);
227 	void		(*bs_rm_4_s)(void *, bus_space_handle_t,
228 			    bus_size_t, uint32_t *, bus_size_t);
229 	void		(*bs_rm_8_s)(void *, bus_space_handle_t,
230 			    bus_size_t, uint64_t *, bus_size_t);
231 
232 	/* read region stream */
233 	void		(*bs_rr_1_s)(void *, bus_space_handle_t,
234 			    bus_size_t, uint8_t *, bus_size_t);
235 	void		(*bs_rr_2_s)(void *, bus_space_handle_t,
236 			    bus_size_t, uint16_t *, bus_size_t);
237 	void		(*bs_rr_4_s)(void *, bus_space_handle_t,
238 			    bus_size_t, uint32_t *, bus_size_t);
239 	void		(*bs_rr_8_s)(void *, bus_space_handle_t,
240 			    bus_size_t, uint64_t *, bus_size_t);
241 
242 	/* write stream (single) */
243 	void		(*bs_w_1_s)(void *, bus_space_handle_t,
244 			    bus_size_t, uint8_t);
245 	void		(*bs_w_2_s)(void *, bus_space_handle_t,
246 			    bus_size_t, uint16_t);
247 	void		(*bs_w_4_s)(void *, bus_space_handle_t,
248 			    bus_size_t, uint32_t);
249 	void		(*bs_w_8_s)(void *, bus_space_handle_t,
250 			    bus_size_t, uint64_t);
251 
252 	/* write multiple stream */
253 	void		(*bs_wm_1_s)(void *, bus_space_handle_t,
254 			    bus_size_t, const uint8_t *, bus_size_t);
255 	void		(*bs_wm_2_s)(void *, bus_space_handle_t,
256 			    bus_size_t, const uint16_t *, bus_size_t);
257 	void		(*bs_wm_4_s)(void *, bus_space_handle_t,
258 			    bus_size_t, const uint32_t *, bus_size_t);
259 	void		(*bs_wm_8_s)(void *, bus_space_handle_t,
260 			    bus_size_t, const uint64_t *, bus_size_t);
261 
262 	/* write region stream */
263 	void		(*bs_wr_1_s)(void *, bus_space_handle_t,
264 			    bus_size_t, const uint8_t *, bus_size_t);
265 	void		(*bs_wr_2_s)(void *, bus_space_handle_t,
266 			    bus_size_t, const uint16_t *, bus_size_t);
267 	void		(*bs_wr_4_s)(void *, bus_space_handle_t,
268 			    bus_size_t, const uint32_t *, bus_size_t);
269 	void		(*bs_wr_8_s)(void *, bus_space_handle_t,
270 			    bus_size_t, const uint64_t *, bus_size_t);
271 #endif	/* __BUS_SPACE_HAS_STREAM_METHODS */
272 
273 #ifdef __BUS_SPACE_HAS_PROBING_METHODS
274 	/* peek */
275 	int		(*bs_pe_1)(void *, bus_space_handle_t,
276 			    bus_size_t, uint8_t *);
277 	int		(*bs_pe_2)(void *, bus_space_handle_t,
278 			    bus_size_t, uint16_t *);
279 	int		(*bs_pe_4)(void *, bus_space_handle_t,
280 			    bus_size_t, uint32_t *);
281 	int		(*bs_pe_8)(void *, bus_space_handle_t,
282 			    bus_size_t, uint64_t *);
283 
284 	/* poke */
285 	int		(*bs_po_1)(void *, bus_space_handle_t,
286 			    bus_size_t, uint8_t);
287 	int		(*bs_po_2)(void *, bus_space_handle_t,
288 			    bus_size_t, uint16_t);
289 	int		(*bs_po_4)(void *, bus_space_handle_t,
290 			    bus_size_t, uint32_t);
291 	int		(*bs_po_8)(void *, bus_space_handle_t,
292 			    bus_size_t, uint64_t);
293 #endif /* __BUS_SPACE_HAS_PROBING_METHODS */
294 };
295 
296 #define BUS_SPACE_ALIGNED_POINTER(p, t) ALIGNED_POINTER(p, t)
297 
298 /* Bus Space DMA macros */
299 
300 /*
301  * Private flags stored in the DMA map.
302  */
303 #define	_BUS_DMAMAP_COHERENT	__BIT(16) /* no cache flush necessary on sync */
304 #define	_BUS_DMAMAP_IS_BOUNCING	__BIT(17) /* is bouncing current xfer */
305 #define	_BUS_DMAMAP_NOALLOC	__BIT(18) /* don't alloc memory from this range */
306 
307 /* Forwards needed by prototypes below. */
308 struct mbuf;
309 struct uio;
310 
311 typedef struct riscv_bus_dma_tag	*bus_dma_tag_t;
312 typedef struct riscv_bus_dmamap		*bus_dmamap_t;
313 
314 #define BUS_DMA_TAG_VALID(t) 		((t) != (bus_dma_tag_t)0)
315 
316 /*
317  *	bus_dma_segment_t
318  *
319  *	Describes a single contiguous DMA transaction.  Values
320  *	are suitable for programming into DMA registers.
321  */
322 struct riscv_bus_dma_segment {
323 	/*
324 	 * PUBLIC MEMBERS: these are used by machine-independent code.
325 	 */
326 	bus_addr_t	ds_addr;	/* DMA address */
327 	bus_size_t	ds_len;		/* length of transfer */
328 
329 	/*
330 	 * PRIVATE MEMBERS:
331 	 */
332 	uint32_t	_ds_flags;	/* _BUS_DMAMAP_COHERENT */
333 };
334 typedef struct riscv_bus_dma_segment	bus_dma_segment_t;
335 
336 /*
337  *	riscv_dma_range
338  *
339  *	This structure describes a valid DMA range.
340  */
341 struct riscv_dma_range {
342 	paddr_t		dr_sysbase;	/* system base address */
343 	bus_addr_t	dr_busbase;	/* appears here on bus */
344 	bus_size_t	dr_len;		/* length of range */
345 	uint32_t	dr_flags;	/* flags for range */
346 };
347 
348 /*
349  *	bus_dma_tag_t
350  *
351  *	A machine-dependent opaque type describing the implementation of
352  *	DMA for a given bus.
353  */
354 
355 struct riscv_bus_dma_tag {
356 	/*
357 	 * DMA range for this tag.  If the page doesn't fall within
358 	 * one of these ranges, an error is returned.  The caller
359 	 * may then decide what to do with the transfer.  If the
360 	 * range pointer is NULL, it is ignored.
361 	 */
362 	struct riscv_dma_range *_ranges;
363 	int _nranges;
364 
365 	/*
366 	 * Opaque cookie for use by back-end.
367 	 */
368 	void *_cookie;
369 
370 	/*
371 	 * DMA mapping methods.
372 	 */
373 	int	(*_dmamap_create)(bus_dma_tag_t, bus_size_t, int,
374 		    bus_size_t, bus_size_t, int, bus_dmamap_t *);
375 	void	(*_dmamap_destroy)(bus_dma_tag_t, bus_dmamap_t);
376 	int	(*_dmamap_load)(bus_dma_tag_t, bus_dmamap_t, void *,
377 		    bus_size_t, struct proc *, int);
378 	int	(*_dmamap_load_mbuf)(bus_dma_tag_t, bus_dmamap_t,
379 		    struct mbuf *, int);
380 	int	(*_dmamap_load_uio)(bus_dma_tag_t, bus_dmamap_t,
381 		    struct uio *, int);
382 	int	(*_dmamap_load_raw)(bus_dma_tag_t, bus_dmamap_t,
383 		    bus_dma_segment_t *, int, bus_size_t, int);
384 	void	(*_dmamap_unload)(bus_dma_tag_t, bus_dmamap_t);
385 	void	(*_dmamap_sync)(bus_dma_tag_t, bus_dmamap_t,
386 		    bus_addr_t, bus_size_t, int);
387 
388 	/*
389 	 * DMA memory utility functions.
390 	 */
391 	int	(*_dmamem_alloc)(bus_dma_tag_t, bus_size_t, bus_size_t,
392 		    bus_size_t, bus_dma_segment_t *, int, int *, int);
393 	void	(*_dmamem_free)(bus_dma_tag_t,
394 		    bus_dma_segment_t *, int);
395 	int	(*_dmamem_map)(bus_dma_tag_t, bus_dma_segment_t *,
396 		    int, size_t, void **, int);
397 	void	(*_dmamem_unmap)(bus_dma_tag_t, void *, size_t);
398 	paddr_t	(*_dmamem_mmap)(bus_dma_tag_t, bus_dma_segment_t *,
399 		    int, off_t, int, int);
400 
401 	/*
402 	 * DMA tag utility functions
403 	 */
404 	int	(*_dmatag_subregion)(bus_dma_tag_t, bus_addr_t, bus_addr_t,
405 		     bus_dma_tag_t *, int);
406 	void	(*_dmatag_destroy)(bus_dma_tag_t);
407 
408 	/*
409 	 * State for bounce buffers
410 	 */
411 	int	_tag_needs_free;
412 	int	(*_may_bounce)(bus_dma_tag_t, bus_dmamap_t, int, int *);
413 };
414 
415 /*
416  *	bus_dmamap_t
417  *
418  *	Describes a DMA mapping.
419  */
420 struct riscv_bus_dmamap {
421 	/*
422 	 * PRIVATE MEMBERS: not for use by machine-independent code.
423 	 */
424 	bus_size_t	_dm_size;	/* largest DMA transfer mappable */
425 	int		_dm_segcnt;	/* number of segs this map can map */
426 	bus_size_t	_dm_maxmaxsegsz; /* fixed largest possible segment */
427 	bus_size_t	_dm_boundary;	/* don't cross this */
428 	int		_dm_flags;	/* misc. flags */
429 
430 	void		*_dm_origbuf;	/* pointer to original buffer */
431 	int		_dm_buftype;	/* type of buffer */
432 	struct vmspace	*_dm_vmspace;	/* vmspace that owns the mapping */
433 
434 	void		*_dm_cookie;	/* cookie for bus-specific functions */
435 
436 	/*
437 	 * PUBLIC MEMBERS: these are used by machine-independent code.
438 	 */
439 
440 	bus_size_t	dm_maxsegsz;	/* largest possible segment */
441 	bus_size_t	dm_mapsize;	/* size of the mapping */
442 	int		dm_nsegs;	/* # valid segments in mapping */
443 	bus_dma_segment_t dm_segs[1];	/* segments; variable length */
444 };
445 
446 /* _dm_buftype */
447 #define	_BUS_DMA_BUFTYPE_INVALID	0
448 #define	_BUS_DMA_BUFTYPE_LINEAR		1
449 #define	_BUS_DMA_BUFTYPE_MBUF		2
450 #define	_BUS_DMA_BUFTYPE_UIO		3
451 #define	_BUS_DMA_BUFTYPE_RAW		4
452 
453 #ifdef _RISCV_BUS_DMA_PRIVATE
454 /*
455  * Cookie used for bounce buffers. A pointer to one of these it stashed in
456  * the DMA map.
457  */
458 struct riscv_bus_dma_cookie {
459 	int	id_flags;		 /* flags; see below */
460 
461 	/*
462 	 * Information about the original buffer used during
463 	 * DMA map syncs.  Note that origibuflen is only used
464 	 * for ID_BUFTYPE_LINEAR.
465 	 */
466 	union {
467 		void	*un_origbuf;	 /* pointer to orig buffer if
468 					    bouncing */
469 		char	*un_linearbuf;
470 		struct mbuf	*un_mbuf;
471 		struct uio	*un_uio;
472 	} id_origbuf_un;
473 #define	id_origbuf		id_origbuf_un.un_origbuf
474 #define	id_origlinearbuf	id_origbuf_un.un_linearbuf
475 #define	id_origmbuf		id_origbuf_un.un_mbuf
476 #define	id_origuio		id_origbuf_un.un_uio
477 	bus_size_t	id_origbuflen;	 /* ...and size */
478 
479 	void		*id_bouncebuf;	 /* pointer to the bounce buffer */
480 	bus_size_t	id_bouncebuflen; /* ...and size */
481 	int		id_nbouncesegs;	 /* number of valid bounce segs */
482 	bus_dma_segment_t
483 			id_bouncesegs[0];/* array of bounce buffer */
484 					 /* ... physical memory segments */
485 };
486 
487 /* id_flags */
488 #define	_BUS_DMA_IS_BOUNCING		__BIT(2)	/* is bouncing current xfer */
489 #define	_BUS_DMA_HAS_BOUNCE		__BIT(1)	/* has bounce buffers */
490 #endif /* _RISCV_BUS_DMA_PRIVATE */
491 #define	_BUS_DMA_MIGHT_NEED_BOUNCE	__BIT(0)	/* may need bounce buffers */
492 
493 #endif /* _RISCV_BUS_DEFS_H_ */
494