2 * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
7 * NASA Ames Research Center.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the NetBSD
20 * Foundation, Inc. and its contributors.
21 * 4. Neither the name of The NetBSD Foundation nor the names of its
22 * contributors may be used to endorse or promote products derived
23 * from this software without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
26 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
38 * Copyright (c) 1992, 1993
39 * The Regents of the University of California. All rights reserved.
41 * This software was developed by the Computer Systems Engineering group
42 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
43 * contributed to Berkeley.
45 * Redistribution and use in source and binary forms, with or without
46 * modification, are permitted provided that the following conditions
48 * 1. Redistributions of source code must retain the above copyright
49 * notice, this list of conditions and the following disclaimer.
50 * 2. Redistributions in binary form must reproduce the above copyright
51 * notice, this list of conditions and the following disclaimer in the
52 * documentation and/or other materials provided with the distribution.
53 * 4. Neither the name of the University nor the names of its contributors
54 * may be used to endorse or promote products derived from this software
55 * without specific prior written permission.
57 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
58 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
59 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
60 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
61 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
62 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
63 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
64 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
65 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
66 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
70 * Copyright (c) 1997, 1998 Justin T. Gibbs.
71 * All rights reserved.
72 * Copyright 2001 by Thomas Moestl <tmm@FreeBSD.org>. All rights reserved.
74 * Redistribution and use in source and binary forms, with or without
75 * modification, are permitted provided that the following conditions
77 * 1. Redistributions of source code must retain the above copyright
78 * notice, this list of conditions, and the following disclaimer,
79 * without modification, immediately at the beginning of the file.
80 * 2. The name of the author may not be used to endorse or promote products
81 * derived from this software without specific prior written permission.
83 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
84 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
85 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
86 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
87 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
88 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
89 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
90 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
91 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
92 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
95 * from: @(#)machdep.c 8.6 (Berkeley) 1/14/94
96 * from: NetBSD: machdep.c,v 1.111 2001/09/15 07:13:40 eeh Exp
98 * from: FreeBSD: src/sys/i386/i386/busdma_machdep.c,v 1.24 2001/08/15
101 #include <sys/cdefs.h>
102 __FBSDID("$FreeBSD$");
104 #include <sys/param.h>
106 #include <sys/lock.h>
107 #include <sys/malloc.h>
108 #include <sys/mbuf.h>
109 #include <sys/mutex.h>
110 #include <sys/proc.h>
112 #include <sys/systm.h>
116 #include <vm/vm_extern.h>
117 #include <vm/vm_kern.h>
118 #include <vm/vm_page.h>
119 #include <vm/vm_param.h>
120 #include <vm/vm_map.h>
122 #include <machine/asi.h>
123 #include <machine/atomic.h>
124 #include <machine/bus.h>
125 #include <machine/bus_private.h>
126 #include <machine/cache.h>
127 #include <machine/smp.h>
128 #include <machine/tlb.h>
130 static void nexus_bus_barrier(bus_space_tag_t, bus_space_handle_t,
131 bus_size_t, bus_size_t, int);
133 /* ASIs for bus access */
134 const int bus_type_asi[] = {
135 ASI_PHYS_BYPASS_EC_WITH_EBIT, /* nexus */
136 ASI_PHYS_BYPASS_EC_WITH_EBIT, /* SBus */
137 ASI_PHYS_BYPASS_EC_WITH_EBIT_L, /* PCI configuration space */
138 ASI_PHYS_BYPASS_EC_WITH_EBIT_L, /* PCI memory space */
139 ASI_PHYS_BYPASS_EC_WITH_EBIT_L, /* PCI I/O space */
143 const int bus_stream_asi[] = {
144 ASI_PHYS_BYPASS_EC_WITH_EBIT, /* nexus */
145 ASI_PHYS_BYPASS_EC_WITH_EBIT, /* SBus */
146 ASI_PHYS_BYPASS_EC_WITH_EBIT, /* PCI configuration space */
147 ASI_PHYS_BYPASS_EC_WITH_EBIT, /* PCI memory space */
148 ASI_PHYS_BYPASS_EC_WITH_EBIT, /* PCI I/O space */
153 * Convenience function for manipulating driver locks from busdma (during
154 * busdma_swi, for example). Drivers that don't provide their own locks
155 * should specify &Giant to dmat->lockfuncarg. Drivers that use their own
156 * non-mutex locking scheme don't have to use this at all.
159 busdma_lock_mutex(void *arg, bus_dma_lock_op_t op)
163 dmtx = (struct mtx *)arg;
172 panic("Unknown operation 0x%x for busdma_lock_mutex!", op);
177 * dflt_lock should never get called. It gets put into the dma tag when
178 * lockfunc == NULL, which is only valid if the maps that are associated
179 * with the tag are meant to never be defered.
180 * XXX Should have a way to identify which driver is responsible here.
183 dflt_lock(void *arg, bus_dma_lock_op_t op)
186 panic("driver error: busdma dflt_lock called");
190 * Allocate a device specific dma_tag.
193 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
194 bus_size_t boundary, bus_addr_t lowaddr, bus_addr_t highaddr,
195 bus_dma_filter_t *filter, void *filterarg, bus_size_t maxsize,
196 int nsegments, bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
197 void *lockfuncarg, bus_dma_tag_t *dmat)
199 bus_dma_tag_t newtag;
201 /* Return a NULL tag on failure */
204 /* Enforce the usage of BUS_GET_DMA_TAG(). */
206 panic("%s: parent DMA tag NULL", __func__);
208 newtag = (bus_dma_tag_t)malloc(sizeof(*newtag), M_DEVBUF, M_NOWAIT);
213 * The method table pointer and the cookie need to be taken over from
216 newtag->dt_cookie = parent->dt_cookie;
217 newtag->dt_mt = parent->dt_mt;
219 newtag->dt_parent = parent;
220 newtag->dt_alignment = alignment;
221 newtag->dt_boundary = boundary;
222 newtag->dt_lowaddr = trunc_page((vm_offset_t)lowaddr) + (PAGE_SIZE - 1);
223 newtag->dt_highaddr = trunc_page((vm_offset_t)highaddr) +
225 newtag->dt_filter = filter;
226 newtag->dt_filterarg = filterarg;
227 newtag->dt_maxsize = maxsize;
228 newtag->dt_nsegments = nsegments;
229 newtag->dt_maxsegsz = maxsegsz;
230 newtag->dt_flags = flags;
231 newtag->dt_ref_count = 1; /* Count ourselves */
232 newtag->dt_map_count = 0;
234 if (lockfunc != NULL) {
235 newtag->dt_lockfunc = lockfunc;
236 newtag->dt_lockfuncarg = lockfuncarg;
238 newtag->dt_lockfunc = dflt_lock;
239 newtag->dt_lockfuncarg = NULL;
242 newtag->dt_segments = NULL;
244 /* Take into account any restrictions imposed by our parent tag. */
245 newtag->dt_lowaddr = ulmin(parent->dt_lowaddr, newtag->dt_lowaddr);
246 newtag->dt_highaddr = ulmax(parent->dt_highaddr, newtag->dt_highaddr);
247 if (newtag->dt_boundary == 0)
248 newtag->dt_boundary = parent->dt_boundary;
249 else if (parent->dt_boundary != 0)
250 newtag->dt_boundary = ulmin(parent->dt_boundary,
251 newtag->dt_boundary);
252 atomic_add_int(&parent->dt_ref_count, 1);
254 if (newtag->dt_boundary > 0)
255 newtag->dt_maxsegsz = ulmin(newtag->dt_maxsegsz,
256 newtag->dt_boundary);
263 bus_dma_tag_destroy(bus_dma_tag_t dmat)
265 bus_dma_tag_t parent;
268 if (dmat->dt_map_count != 0)
270 while (dmat != NULL) {
271 parent = dmat->dt_parent;
272 atomic_subtract_int(&dmat->dt_ref_count, 1);
273 if (dmat->dt_ref_count == 0) {
274 if (dmat->dt_segments != NULL)
275 free(dmat->dt_segments, M_DEVBUF);
276 free(dmat, M_DEVBUF);
278 * Last reference count, so
279 * release our reference
280 * count on our parent.
290 /* Allocate/free a tag, and do the necessary management work. */
292 sparc64_dma_alloc_map(bus_dma_tag_t dmat, bus_dmamap_t *mapp)
295 if (dmat->dt_segments == NULL) {
296 dmat->dt_segments = (bus_dma_segment_t *)malloc(
297 sizeof(bus_dma_segment_t) * dmat->dt_nsegments, M_DEVBUF,
299 if (dmat->dt_segments == NULL)
302 *mapp = malloc(sizeof(**mapp), M_DEVBUF, M_NOWAIT | M_ZERO);
306 SLIST_INIT(&(*mapp)->dm_reslist);
307 dmat->dt_map_count++;
312 sparc64_dma_free_map(bus_dma_tag_t dmat, bus_dmamap_t map)
316 dmat->dt_map_count--;
320 nexus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
323 return (sparc64_dma_alloc_map(dmat, mapp));
327 nexus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
330 sparc64_dma_free_map(dmat, map);
335 * Utility function to load a linear buffer. lastaddrp holds state
336 * between invocations (for multiple-buffer loads). segp contains
337 * the starting segment on entrace, and the ending segment on exit.
338 * first indicates if this is the first invocation of this function.
341 _nexus_dmamap_load_buffer(bus_dma_tag_t dmat, void *buf, bus_size_t buflen,
342 struct thread *td, int flags, bus_addr_t *lastaddrp,
343 bus_dma_segment_t *segs, int *segp, int first)
346 bus_addr_t curaddr, lastaddr, baddr, bmask;
347 vm_offset_t vaddr = (vm_offset_t)buf;
352 pmap = vmspace_pmap(td->td_proc->p_vmspace);
356 lastaddr = *lastaddrp;
357 bmask = ~(dmat->dt_boundary - 1);
359 for (seg = *segp; buflen > 0 ; ) {
361 * Get the physical address for this segment.
364 curaddr = pmap_extract(pmap, vaddr);
366 curaddr = pmap_kextract(vaddr);
369 * Compute the segment size, and adjust counts.
371 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
372 if (sgsize > dmat->dt_maxsegsz)
373 sgsize = dmat->dt_maxsegsz;
378 * Make sure we don't cross any boundaries.
380 if (dmat->dt_boundary > 0) {
381 baddr = (curaddr + dmat->dt_boundary) & bmask;
382 if (sgsize > (baddr - curaddr))
383 sgsize = (baddr - curaddr);
387 * Insert chunk into a segment, coalescing with
388 * previous segment if possible.
391 segs[seg].ds_addr = curaddr;
392 segs[seg].ds_len = sgsize;
395 if (curaddr == lastaddr &&
396 (segs[seg].ds_len + sgsize) <= dmat->dt_maxsegsz &&
397 (dmat->dt_boundary == 0 ||
398 (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
399 segs[seg].ds_len += sgsize;
401 if (++seg >= dmat->dt_nsegments)
403 segs[seg].ds_addr = curaddr;
404 segs[seg].ds_len = sgsize;
408 lastaddr = curaddr + sgsize;
414 *lastaddrp = lastaddr;
419 return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
423 * Common function for loading a DMA map with a linear buffer. May
424 * be called by bus-specific DMA map load functions.
426 * Most SPARCs have IOMMUs in the bus controllers. In those cases
427 * they only need one segment and will use virtual addresses for DVMA.
428 * Those bus controllers should intercept these vectors and should
429 * *NEVER* call nexus_dmamap_load() which is used only by devices that
433 nexus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
434 bus_size_t buflen, bus_dmamap_callback_t *callback, void *callback_arg,
440 error = _nexus_dmamap_load_buffer(dmat, buf, buflen, NULL, flags,
441 &lastaddr, dmat->dt_segments, &nsegs, 1);
444 (*callback)(callback_arg, dmat->dt_segments, nsegs + 1, 0);
445 map->dm_flags |= DMF_LOADED;
447 (*callback)(callback_arg, NULL, 0, error);
453 * Like nexus_dmamap_load(), but for mbufs.
456 nexus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map, struct mbuf *m0,
457 bus_dmamap_callback2_t *callback, void *callback_arg, int flags)
465 if (m0->m_pkthdr.len <= dmat->dt_maxsize) {
467 bus_addr_t lastaddr = 0;
470 for (m = m0; m != NULL && error == 0; m = m->m_next) {
472 error = _nexus_dmamap_load_buffer(dmat,
473 m->m_data, m->m_len,NULL, flags, &lastaddr,
474 dmat->dt_segments, &nsegs, first);
483 /* force "no valid mappings" in callback */
484 (*callback)(callback_arg, dmat->dt_segments, 0, 0, error);
486 map->dm_flags |= DMF_LOADED;
487 (*callback)(callback_arg, dmat->dt_segments, nsegs + 1,
488 m0->m_pkthdr.len, error);
494 nexus_dmamap_load_mbuf_sg(bus_dma_tag_t dmat, bus_dmamap_t map, struct mbuf *m0,
495 bus_dma_segment_t *segs, int *nsegs, int flags)
503 if (m0->m_pkthdr.len <= dmat->dt_maxsize) {
505 bus_addr_t lastaddr = 0;
508 for (m = m0; m != NULL && error == 0; m = m->m_next) {
510 error = _nexus_dmamap_load_buffer(dmat,
511 m->m_data, m->m_len,NULL, flags, &lastaddr,
525 * Like nexus_dmamap_load(), but for uios.
528 nexus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map, struct uio *uio,
529 bus_dmamap_callback2_t *callback, void *callback_arg, int flags)
532 int nsegs, error, first, i;
535 struct thread *td = NULL;
537 resid = uio->uio_resid;
540 if (uio->uio_segflg == UIO_USERSPACE) {
542 KASSERT(td != NULL, ("%s: USERSPACE but no proc", __func__));
548 for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
550 * Now at the first iovec to load. Load each iovec
551 * until we have exhausted the residual count.
554 resid < iov[i].iov_len ? resid : iov[i].iov_len;
555 caddr_t addr = (caddr_t) iov[i].iov_base;
558 error = _nexus_dmamap_load_buffer(dmat, addr, minlen,
559 td, flags, &lastaddr, dmat->dt_segments, &nsegs,
568 /* force "no valid mappings" in callback */
569 (*callback)(callback_arg, dmat->dt_segments, 0, 0, error);
571 map->dm_flags |= DMF_LOADED;
572 (*callback)(callback_arg, dmat->dt_segments, nsegs + 1,
573 uio->uio_resid, error);
579 * Common function for unloading a DMA map. May be called by
580 * bus-specific DMA map unload functions.
583 nexus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
586 map->dm_flags &= ~DMF_LOADED;
590 * Common function for DMA map synchronization. May be called
591 * by bus-specific DMA map synchronization functions.
594 nexus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
598 * We sync out our caches, but the bus must do the same.
600 * Actually a #Sync is expensive. We should optimize.
602 if ((op & BUS_DMASYNC_PREREAD) || (op & BUS_DMASYNC_PREWRITE)) {
604 * Don't really need to do anything, but flush any pending
609 if (op & BUS_DMASYNC_POSTWRITE) {
610 /* Nothing to do. Handled by the bus controller. */
615 * Common function for DMA-safe memory allocation. May be called
616 * by bus-specific DMA memory allocation functions.
619 nexus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr, int flags,
624 if (flags & BUS_DMA_NOWAIT)
628 if (flags & BUS_DMA_ZERO)
633 * (dmat->dt_alignment < dmat->dt_maxsize) is just a quick hack; the
634 * exact alignment guarantees of malloc need to be nailed down, and
635 * the code below should be rewritten to take that into account.
637 * In the meantime, we'll warn the user if malloc gets it wrong.
639 if (dmat->dt_maxsize <= PAGE_SIZE &&
640 dmat->dt_alignment < dmat->dt_maxsize)
641 *vaddr = malloc(dmat->dt_maxsize, M_DEVBUF, mflags);
644 * XXX use contigmalloc until it is merged into this
645 * facility and handles multi-seg allocations. Nobody
646 * is doing multi-seg allocations yet though.
648 *vaddr = contigmalloc(dmat->dt_maxsize, M_DEVBUF, mflags,
649 0ul, dmat->dt_lowaddr,
650 dmat->dt_alignment ? dmat->dt_alignment : 1UL,
655 if ((uintptr_t)*vaddr % dmat->dt_alignment)
656 printf("%s: failed to align memory properly.\n", __func__);
661 * Common function for freeing DMA-safe memory. May be called by
662 * bus-specific DMA memory free functions.
665 nexus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
668 if (dmat->dt_maxsize <= PAGE_SIZE &&
669 dmat->dt_alignment < dmat->dt_maxsize)
670 free(vaddr, M_DEVBUF);
672 contigfree(vaddr, dmat->dt_maxsize, M_DEVBUF);
675 struct bus_dma_methods nexus_dma_methods = {
677 nexus_dmamap_destroy,
679 nexus_dmamap_load_mbuf,
680 nexus_dmamap_load_mbuf_sg,
681 nexus_dmamap_load_uio,
688 struct bus_dma_tag nexus_dmatag = {
710 * Helpers to map/unmap bus memory
713 sparc64_bus_mem_map(bus_space_tag_t tag, bus_space_handle_t handle,
714 bus_size_t size, int flags, vm_offset_t vaddr, void **hp)
723 addr = (vm_offset_t)handle;
724 size = round_page(size);
726 printf("%s: zero size\n", __func__);
729 switch (tag->bst_type) {
730 case PCI_CONFIG_BUS_SPACE:
731 case PCI_IO_BUS_SPACE:
732 case PCI_MEMORY_BUS_SPACE:
740 if (!(flags & BUS_SPACE_MAP_CACHEABLE))
744 sva = trunc_page(vaddr);
746 if ((sva = kmem_alloc_nofault(kernel_map, size)) == 0)
747 panic("%s: cannot allocate virtual memory", __func__);
750 /* Preserve page offset. */
751 *hp = (void *)(sva | ((u_long)addr & PAGE_MASK));
753 pa = trunc_page(addr);
754 if ((flags & BUS_SPACE_MAP_READONLY) == 0)
760 pmap_kenter_flags(va, pa, pm_flags);
763 } while ((vsz -= PAGE_SIZE) > 0);
764 tlb_range_demap(kernel_pmap, sva, sva + size - 1);
769 sparc64_bus_mem_unmap(void *bh, bus_size_t size)
775 sva = trunc_page((vm_offset_t)bh);
776 endva = sva + round_page(size);
777 for (va = sva; va < endva; va += PAGE_SIZE)
778 pmap_kremove_flags(va);
779 tlb_range_demap(kernel_pmap, sva, sva + size - 1);
780 kmem_free(kernel_map, sva, size);
785 * Fake up a bus tag, for use by console drivers in early boot when the
786 * regular means to allocate resources are not yet available.
787 * Addr is the physical address of the desired start of the handle.
790 sparc64_fake_bustag(int space, bus_addr_t addr, struct bus_space_tag *ptag)
793 ptag->bst_cookie = NULL;
794 ptag->bst_parent = NULL;
795 ptag->bst_type = space;
796 ptag->bst_bus_barrier = nexus_bus_barrier;
801 * Base bus space handlers.
805 nexus_bus_barrier(bus_space_tag_t t, bus_space_handle_t h, bus_size_t offset,
806 bus_size_t size, int flags)
810 * We have lots of alternatives depending on whether we're
811 * synchronizing loads with loads, loads with stores, stores
812 * with loads, or stores with stores. The only ones that seem
813 * generic are #Sync and #MemIssue. I'll use #Sync for safety.
816 case BUS_SPACE_BARRIER_READ | BUS_SPACE_BARRIER_WRITE:
817 case BUS_SPACE_BARRIER_READ:
818 case BUS_SPACE_BARRIER_WRITE:
822 panic("%s: unknown flags", __func__);
827 struct bus_space_tag nexus_bustag = {
829 NULL, /* parent bus tag */
830 NEXUS_BUS_SPACE, /* type */
831 nexus_bus_barrier, /* bus_space_barrier */