OpenGrok

/*	$NetBSD: bus.c,v 1.69 2023/12/07 16:56:09 thorpej Exp $	*/

/*-
 * Copyright (c) 1998 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 and by Chris G. Demetriou.
 *
 * 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.
 */

#include "opt_m68k_arch.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bus.c,v 1.69 2023/12/07 16:56:09 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/extent.h>
#include <sys/kmem.h>
#include <sys/mbuf.h>
#include <sys/proc.h>
#include <sys/vmem_impl.h>

#include <uvm/uvm.h>

#include <machine/cpu.h>
#include <m68k/cacheops.h>
#define	_ATARI_BUS_DMA_PRIVATE
#include <sys/bus.h>

/*
 * Vmem arena to manage all memory space, including I/O ranges.  Allocate
 * storage for 16 regions in each, initially.
 *
 * This means that the fixed static storage is only used for registrating
 * the found memory regions and the bus-mapping of the console.
 */
#define	IOMEM_BTAG_COUNT	VMEM_EST_BTCOUNT(1, 16)
static struct vmem iomem_arena_store;
static struct vmem_btag iomem_btag_store[IOMEM_BTAG_COUNT];
static vmem_t *iomem_arena;

static int  _bus_dmamap_load_buffer(bus_dma_tag_t tag, bus_dmamap_t,
		void *, bus_size_t, struct vmspace *, int, paddr_t *,
		int *, int);
static int  bus_mem_add_mapping(bus_space_tag_t t, bus_addr_t bpa,
		bus_size_t size, int flags, bus_space_handle_t *bsph);

extern paddr_t avail_end;

/*
 * We need these for the early memory allocator. The idea is this:
 * Allocate VA-space through ptextra (atari_init.c:startc()). When
 * The VA & size of this space are known, call bootm_init().
 * Until the VM-system is up, bus_mem_add_mapping() allocates its virtual
 * addresses from this extent-map.
 *
 * This allows for the console code to use the bus_space interface at a
 * very early stage of the system configuration.
 */
static pt_entry_t	*bootm_ptep;
static vaddr_t		 bootm_start;
static vaddr_t		 bootm_end;		/* inclusive */
#define	BOOTM_BTAG_COUNT	VMEM_EST_BTCOUNT(1, 32)
static struct vmem	 bootm_arena_store;
static struct vmem_btag	 bootm_btag_store[BOOTM_BTAG_COUNT];
static vmem_t *		 bootm_arena;

static vaddr_t	bootm_alloc(paddr_t pa, u_long size, int flags);
static int	bootm_free(vaddr_t va, u_long size);

void
bootm_init(vaddr_t va, void *ptep, vsize_t size)
{

	bootm_start = va;
	bootm_end = va + size - 1;
	bootm_ptep = (pt_entry_t *)ptep;

	bootm_arena = vmem_init(&bootm_arena_store,
				"bootmem",		/* name */
				0,			/* addr */
				0,			/* size */
				PAGE_SIZE,		/* quantum */
				NULL,			/* importfn */
				NULL,			/* releasefn */
				NULL,			/* source */
				0,			/* qcache_max */
				VM_NOSLEEP | VM_PRIVTAGS,
				IPL_NONE);

	vmem_add_bts(bootm_arena, bootm_btag_store, BOOTM_BTAG_COUNT);
	vmem_add(bootm_arena, va, size, VM_NOSLEEP);
}

vaddr_t
bootm_alloc(paddr_t pa, u_long size, int flags)
{
	pt_entry_t	*pg, *epg;
	pt_entry_t	pg_proto;
	vmem_addr_t	rva;
	vaddr_t		va;

	if (vmem_alloc(bootm_arena, size, VM_NOSLEEP, &rva) != 0) {
		printf("bootm_alloc fails! Not enough fixed boundary tags?\n");
		printf("Requested extent: pa=%lx, size=%lx\n",
						(u_long)pa, size);
		return 0;
	}

	pg  = &bootm_ptep[btoc(rva - bootm_start)];
	epg = &pg[btoc(size)];
	va  = rva;
	pg_proto = pa | PG_RW | PG_V;
	if ((flags & BUS_SPACE_MAP_CACHEABLE) == 0)
		pg_proto |= PG_CI;
	while (pg < epg) {
		*pg++     = pg_proto;
		pg_proto += PAGE_SIZE;
#if defined(M68040) || defined(M68060)
		if (mmutype == MMU_68040) {
			DCFP(pa);
			pa += PAGE_SIZE;
		}
#endif
		TBIS(va);
		va += PAGE_SIZE;
	}
	return rva;
}

int
bootm_free(vaddr_t va, u_long size)
{

	if ((va < bootm_start) || ((va + size - 1) > bootm_end))
		return 0; /* Not for us! */
	vmem_free(bootm_arena, va, size);
	return 1;
}

void
atari_bus_space_arena_init(paddr_t startpa, paddr_t endpa)
{
	vmem_size_t size;

	/*
	 * Initialize the I/O mem vmem arena.
	 *
	 * Note: we don't have to check the return value since
	 * creation of a fixed extent map will never fail (since
	 * descriptor storage has already been allocated).
	 *
	 * N.B. The iomem arena manages _all_ physical addresses
	 * on the machine.  When the amount of RAM is found, all
	 * extents of RAM are allocated from the map.
	 */

	iomem_arena = vmem_init(&iomem_arena_store,
				"iomem",		/* name */
				0,			/* addr */
				0,			/* size */
				1,			/* quantum */
				NULL,			/* importfn */
				NULL,			/* releasefn */
				NULL,			/* source */
				0,			/* qcache_max */
				VM_NOSLEEP | VM_PRIVTAGS,
				IPL_NONE);

	vmem_add_bts(iomem_arena, iomem_btag_store, IOMEM_BTAG_COUNT);

	/* XXX kern/57748 */
	size = (vmem_size_t)(endpa - startpa) + 1;
	if (size == 0) {
		size--;
	}
	vmem_add(iomem_arena, startpa, size, VM_NOSLEEP);
}

int
atari_bus_space_alloc_physmem(paddr_t startpa, paddr_t endpa)
{

	return vmem_xalloc_addr(iomem_arena, startpa, endpa - startpa,
	    VM_NOSLEEP);
}

int
bus_space_map(bus_space_tag_t t, bus_addr_t bpa, bus_size_t size, int flags,
    bus_space_handle_t *mhp)
{
	int	error;

	/*
	 * Before we go any further, let's make sure that this
	 * region is available.
	 */
	error = vmem_xalloc_addr(iomem_arena, bpa + t->base, size,
	    VM_NOSLEEP);
	if (error != 0)
		return error;

	error = bus_mem_add_mapping(t, bpa, size, flags, mhp);
	if (error != 0) {
		vmem_xfree(iomem_arena, bpa + t->base, size);
	}
	return error;
}

int
bus_space_alloc(bus_space_tag_t t, bus_addr_t rstart, bus_addr_t rend,
    bus_size_t size, bus_size_t alignment, bus_size_t boundary, int flags,
    bus_addr_t *bpap, bus_space_handle_t *bshp)
{
	vmem_addr_t bpa;
	int error;

	/*
	 * Do the requested allocation.
	 */
	error = vmem_xalloc(iomem_arena, size,
			    alignment,		/* align */
			    0,			/* phase */
			    boundary,		/* boundary */
			    rstart + t->base,	/* minaddr */
			    rend + t->base,	/* maxaddr */
			    VM_BESTFIT | VM_NOSLEEP,
			    &bpa);
	if (error != 0)
		return error;

	/*
	 * Map the bus physical address to a kernel virtual address.
	 */
	error = bus_mem_add_mapping(t, bpa, size, flags, bshp);
	if (error != 0) {
		vmem_xfree(iomem_arena, bpa, size);
	}

	*bpap = bpa;

	return error;
}

static int
bus_mem_add_mapping(bus_space_tag_t t, bus_addr_t bpa, bus_size_t size,
    int flags, bus_space_handle_t *bshp)
{
	vaddr_t	va;
	paddr_t	pa, endpa;

	pa    = m68k_trunc_page(bpa + t->base);
	endpa = m68k_round_page((bpa + t->base + size) - 1);

#ifdef DIAGNOSTIC
	if (endpa <= pa)
		panic("%s: overflow", __func__);
#endif

	if (kernel_map == NULL) {
		/*
		 * The VM-system is not yet operational, allocate from
		 * a special pool.
		 */
		va = bootm_alloc(pa, endpa - pa, flags);
		if (va == 0)
			return ENOMEM;
		*bshp = va + (bpa & PGOFSET);
		return 0;
	}

	va = uvm_km_alloc(kernel_map, endpa - pa, 0,
	    UVM_KMF_VAONLY | UVM_KMF_NOWAIT);
	if (va == 0)
		return ENOMEM;

	*bshp = va + (bpa & PGOFSET);

	for (; pa < endpa; pa += PAGE_SIZE, va += PAGE_SIZE) {
		pt_entry_t *ptep, npte;

		pmap_enter(pmap_kernel(), (vaddr_t)va, pa,
		    VM_PROT_READ|VM_PROT_WRITE, VM_PROT_READ|VM_PROT_WRITE);

		ptep = kvtopte(va);
		npte = *ptep & ~PG_CMASK;

		if ((flags & BUS_SPACE_MAP_CACHEABLE) == 0)
			npte |= PG_CI;
		else if (mmutype == MMU_68040)
			npte |= PG_CCB;

		*ptep = npte;
	}
	pmap_update(pmap_kernel());
	TBIAS();
	return 0;
}

void
bus_space_unmap(bus_space_tag_t t, bus_space_handle_t bsh, bus_size_t size)
{
	vaddr_t	va, endva;
	paddr_t bpa;

	va = m68k_trunc_page(bsh);
	endva = m68k_round_page(((char *)bsh + size) - 1);
#ifdef DIAGNOSTIC
	if (endva < va)
		panic("%s: overflow", __func__);
#endif

	(void)pmap_extract(pmap_kernel(), va, &bpa);
	bpa += ((paddr_t)bsh & PGOFSET);

	/*
	 * Free the kernel virtual mapping.
	 */
	if (!bootm_free(va, endva - va)) {
		pmap_remove(pmap_kernel(), va, endva);
		pmap_update(pmap_kernel());
		uvm_km_free(kernel_map, va, endva - va, UVM_KMF_VAONLY);
	}

	/*
	 * Mark as free in the extent map.
	 */
	vmem_xfree(iomem_arena, bpa, size);
}

/*
 * Get a new handle for a subregion of an already-mapped area of bus space.
 */
int
bus_space_subregion(bus_space_tag_t t, bus_space_handle_t memh,
    bus_size_t off, bus_size_t sz, bus_space_handle_t *mhp)
{

	*mhp = memh + off;
	return 0;
}

paddr_t
bus_space_mmap(bus_space_tag_t t, bus_addr_t addr, off_t off, int prot,
    int flags)
{

	/*
	 * "addr" is the base address of the device we're mapping.
	 * "off" is the offset into that device.
	 *
	 * Note we are called for each "page" in the device that
	 * the upper layers want to map.
	 */
	return m68k_btop(addr + off);
}

static size_t
_bus_dmamap_mapsize(int const nsegments)
{

	KASSERT(nsegments > 0);
	return sizeof(struct atari_bus_dmamap) +
	    (sizeof(bus_dma_segment_t) * (nsegments - 1));
}

/*
 * Common function for DMA map creation.  May be called by bus-specific
 * DMA map creation functions.
 */
int
_bus_dmamap_create(bus_dma_tag_t t, bus_size_t size, int nsegments,
    bus_size_t maxsegsz, bus_size_t boundary, int flags, bus_dmamap_t *dmamp)
{
	struct atari_bus_dmamap *map;
	void *mapstore;

	/*
	 * Allocate and initialize the DMA map.  The end of the map
	 * is a variable-sized array of segments, so we allocate enough
	 * room for them in one shot.
	 *
	 * Note we don't preserve the WAITOK or NOWAIT flags.  Preservation
	 * of ALLOCNOW notifies others that we've reserved these resources,
	 * and they are not to be freed.
	 *
	 * The bus_dmamap_t includes one bus_dma_segment_t, hence
	 * the (nsegments - 1).
	 */
	if ((mapstore = kmem_zalloc(_bus_dmamap_mapsize(nsegments),
	    (flags & BUS_DMA_NOWAIT) != 0 ? KM_NOSLEEP : KM_SLEEP)) == NULL)
		return ENOMEM;

	map = (struct atari_bus_dmamap *)mapstore;
	map->_dm_size = size;
	map->_dm_segcnt = nsegments;
	map->_dm_maxmaxsegsz = maxsegsz;
	map->_dm_boundary = boundary;
	map->_dm_flags = flags & ~(BUS_DMA_WAITOK|BUS_DMA_NOWAIT);
	map->dm_maxsegsz = maxsegsz;
	map->dm_mapsize = 0;		/* no valid mappings */
	map->dm_nsegs = 0;

	*dmamp = map;
	return 0;
}

/*
 * Common function for DMA map destruction.  May be called by bus-specific
 * DMA map destruction functions.
 */
void
_bus_dmamap_destroy(bus_dma_tag_t t, bus_dmamap_t map)
{

	kmem_free(map, _bus_dmamap_mapsize(map->_dm_segcnt));
}

/*
 * Common function for loading a DMA map with a linear buffer.  May
 * be called by bus-specific DMA map load functions.
 */
int
_bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
    bus_size_t buflen, struct proc *p, int flags)
{
	paddr_t lastaddr;
	int seg, error;
	struct vmspace *vm;

	/*
	 * Make sure that on error condition we return "no valid mappings".
	 */
	map->dm_mapsize = 0;
	map->dm_nsegs = 0;
	KASSERT(map->dm_maxsegsz <= map->_dm_maxmaxsegsz);

	if (buflen > map->_dm_size)
		return EINVAL;

	if (p != NULL) {
		vm = p->p_vmspace;
	} else {
		vm = vmspace_kernel();
	}

	seg = 0;
	error = _bus_dmamap_load_buffer(t, map, buf, buflen, vm, flags,
	    &lastaddr, &seg, 1);
	if (error == 0) {
		map->dm_mapsize = buflen;
		map->dm_nsegs = seg + 1;
	}
	return error;
}

/*
 * Like _bus_dmamap_load(), but for mbufs.
 */
int
_bus_dmamap_load_mbuf(bus_dma_tag_t t, bus_dmamap_t map, struct mbuf *m0,
    int flags)
{
	paddr_t lastaddr;
	int seg, error, first;
	struct mbuf *m;

	/*
	 * Make sure that on error condition we return "no valid mappings."
	 */
	map->dm_mapsize = 0;
	map->dm_nsegs = 0;
	KASSERT(map->dm_maxsegsz <= map->_dm_maxmaxsegsz);

#ifdef DIAGNOSTIC
	if ((m0->m_flags & M_PKTHDR) == 0)
		panic("%s: no packet header", __func__);
#endif

	if (m0->m_pkthdr.len > map->_dm_size)
		return EINVAL;

	first = 1;
	seg = 0;
	error = 0;
	for (m = m0; m != NULL && error == 0; m = m->m_next) {
		if (m->m_len == 0)
			continue;
		error = _bus_dmamap_load_buffer(t, map, m->m_data, m->m_len,
		    vmspace_kernel(), flags, &lastaddr, &seg, first);
		first = 0;
	}
	if (error == 0) {
		map->dm_mapsize = m0->m_pkthdr.len;
		map->dm_nsegs = seg + 1;
	}
	return error;
}

/*
 * Like _bus_dmamap_load(), but for uios.
 */
int
_bus_dmamap_load_uio(bus_dma_tag_t t, bus_dmamap_t map, struct uio *uio,
    int flags)
{
	paddr_t lastaddr;
	int seg, i, error, first;
	bus_size_t minlen, resid;
	struct iovec *iov;
	void *addr;

	/*
	 * Make sure that on error condition we return "no valid mappings."
	 */
	map->dm_mapsize = 0;
	map->dm_nsegs = 0;
	KASSERT(map->dm_maxsegsz <= map->_dm_maxmaxsegsz);

	resid = uio->uio_resid;
	iov = uio->uio_iov;

	first = 1;
	seg = 0;
	error = 0;
	for (i = 0; i < uio->uio_iovcnt && resid != 0 && error == 0; i++) {
		/*
		 * Now at the first iovec to load.  Load each iovec
		 * until we have exhausted the residual count.
		 */
		minlen = resid < iov[i].iov_len ? resid : iov[i].iov_len;
		addr = (void *)iov[i].iov_base;

		error = _bus_dmamap_load_buffer(t, map, addr, minlen,
		    uio->uio_vmspace, flags, &lastaddr, &seg, first);
		first = 0;

		resid -= minlen;
	}
	if (error == 0) {
		map->dm_mapsize = uio->uio_resid;
		map->dm_nsegs = seg + 1;
	}
	return error;
}

/*
 * Like _bus_dmamap_load(), but for raw memory allocated with
 * bus_dmamem_alloc().
 */
int
_bus_dmamap_load_raw(bus_dma_tag_t t, bus_dmamap_t map,
    bus_dma_segment_t *segs, int nsegs, bus_size_t size, int flags)
{

	panic("%s: not implemented", __func__);
}

/*
 * Common function for unloading a DMA map.  May be called by
 * bus-specific DMA map unload functions.
 */
void
_bus_dmamap_unload(bus_dma_tag_t t, bus_dmamap_t map)
{

	/*
	 * No resources to free; just mark the mappings as
	 * invalid.
	 */
	map->dm_maxsegsz = map->_dm_maxmaxsegsz;
	map->dm_mapsize = 0;
	map->dm_nsegs = 0;
}

/*
 * Common function for DMA map synchronization.  May be called
 * by bus-specific DMA map synchronization functions.
 */
void
_bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{
#if defined(M68040) || defined(M68060)
	bus_addr_t p, e, ps, pe;
	bus_size_t seglen;
	bus_dma_segment_t *seg;
	int i;
#endif

#if defined(M68020) || defined(M68030)
#if defined(M68040) || defined(M68060)
	if (cputype == CPU_68020 || cputype == CPU_68030)
#endif
		/* assume no L2 physical cache */
		return;
#endif

#if defined(M68040) || defined(M68060)
	/* If the whole DMA map is uncached, do nothing. */
	if ((map->_dm_flags & BUS_DMA_COHERENT) != 0)
		return;

	/* Short-circuit for unsupported `ops' */
	if ((ops & (BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE)) == 0)
		return;

	/*
	 * flush/purge the cache.
	 */
	for (i = 0; i < map->dm_nsegs && len != 0; i++) {
		seg = &map->dm_segs[i];
		if (seg->ds_len <= offset) {
			/* Segment irrelevant - before requested offset */
			offset -= seg->ds_len;
			continue;
		}

		/*
		 * Now at the first segment to sync; nail
		 * each segment until we have exhausted the
		 * length.
		 */
		seglen = seg->ds_len - offset;
		if (seglen > len)
			seglen = len;

		ps = seg->ds_addr + offset;
		pe = ps + seglen;

		if ((ops & BUS_DMASYNC_PREWRITE) != 0) {
			p = ps & ~CACHELINE_MASK;
			e = (pe + CACHELINE_MASK) & ~CACHELINE_MASK;

			/* flush cacheline */
			while ((p < e) && (p & (CACHELINE_SIZE * 8 - 1)) != 0) {
				DCFL(p);
				p += CACHELINE_SIZE;
			}

			/* flush cachelines per 128bytes */
			while ((p < e) && (p & PAGE_MASK) != 0) {
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
			}

			/* flush page */
			while (p + PAGE_SIZE <= e) {
				DCFP(p);
				p += PAGE_SIZE;
			}

			/* flush cachelines per 128bytes */
			while (p + CACHELINE_SIZE * 8 <= e) {
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
				DCFL(p);
				p += CACHELINE_SIZE;
			}

			/* flush cacheline */
			while (p < e) {
				DCFL(p);
				p += CACHELINE_SIZE;
			}
		}

		/*
		 * Normally, the `PREREAD' flag instructs us to purge the
		 * cache for the specified offset and length. However, if
		 * the offset/length is not aligned to a cacheline boundary,
		 * we may end up purging some legitimate data from the
		 * start/end of the cache. In such a case, *flush* the
		 * cachelines at the start and end of the required region.
		 */
		else if ((ops & BUS_DMASYNC_PREREAD) != 0) {
			/* flush cacheline on start boundary */
			if ((ps & CACHELINE_MASK) != 0) {
				DCFL(ps & ~CACHELINE_MASK);
			}

			p = (ps + CACHELINE_MASK) & ~CACHELINE_MASK;
			e = pe & ~CACHELINE_MASK;

			/* purge cacheline */
			while ((p < e) && (p & (CACHELINE_SIZE * 8 - 1)) != 0) {
				DCPL(p);
				p += CACHELINE_SIZE;
			}

			/* purge cachelines per 128bytes */
			while ((p < e) && (p & PAGE_MASK) != 0) {
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
			}

			/* purge page */
			while (p + PAGE_SIZE <= e) {
				DCPP(p);
				p += PAGE_SIZE;
			}

			/* purge cachelines per 128bytes */
			while (p + CACHELINE_SIZE * 8 <= e) {
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
				DCPL(p);
				p += CACHELINE_SIZE;
			}

			/* purge cacheline */
			while (p < e) {
				DCPL(p);
				p += CACHELINE_SIZE;
			}

			/* flush cacheline on end boundary */
			if (p < pe) {
				DCFL(p);
			}
		}
		offset = 0;
		len -= seglen;
	}
#endif	/* defined(M68040) || defined(M68060) */
}

/*
 * Common function for DMA-safe memory allocation.  May be called
 * by bus-specific DMA memory allocation functions.
 */
int
bus_dmamem_alloc(bus_dma_tag_t t, bus_size_t size, bus_size_t alignment,
    bus_size_t boundary, bus_dma_segment_t *segs, int nsegs, int *rsegs,
    int flags)
{

	return bus_dmamem_alloc_range(t, size, alignment, boundary,
	    segs, nsegs, rsegs, flags, 0, trunc_page(avail_end));
}

/*
 * Common function for freeing DMA-safe memory.  May be called by
 * bus-specific DMA memory free functions.
 */
void
bus_dmamem_free(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs)
{
	struct vm_page *m;
	bus_addr_t addr, offset;
	struct pglist mlist;
	int curseg;

	offset = t->_displacement;

	/*
	 * Build a list of pages to free back to the VM system.
	 */
	TAILQ_INIT(&mlist);
	for (curseg = 0; curseg < nsegs; curseg++) {
		for (addr = segs[curseg].ds_addr;
		    addr < (segs[curseg].ds_addr + segs[curseg].ds_len);
		    addr += PAGE_SIZE) {
			m = PHYS_TO_VM_PAGE(addr - offset);
			TAILQ_INSERT_TAIL(&mlist, m, pageq.queue);
		}
	}

	uvm_pglistfree(&mlist);
}

/*
 * Common function for mapping DMA-safe memory.  May be called by
 * bus-specific DMA memory map functions.
 */
int
bus_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
    size_t size, void **kvap, int flags)
{
	vaddr_t va;
	bus_addr_t addr, offset;
	int curseg;
	const uvm_flag_t kmflags =
	    (flags & BUS_DMA_NOWAIT) != 0 ? UVM_KMF_NOWAIT : 0;

	offset = t->_displacement;

	size = round_page(size);

	va = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_VAONLY | kmflags);

	if (va == 0)
		return ENOMEM;

	*kvap = (void *)va;

	for (curseg = 0; curseg < nsegs; curseg++) {
		for (addr = segs[curseg].ds_addr;
		    addr < (segs[curseg].ds_addr + segs[curseg].ds_len);
		    addr += PAGE_SIZE, va += PAGE_SIZE, size -= PAGE_SIZE) {
			if (size == 0)
				panic("%s: size botch", __func__);
			pmap_enter(pmap_kernel(), va, addr - offset,
			    VM_PROT_READ | VM_PROT_WRITE,
			    VM_PROT_READ | VM_PROT_WRITE);
		}
	}
	pmap_update(pmap_kernel());

	return 0;
}

/*
 * Common function for unmapping DMA-safe memory.  May be called by
 * bus-specific DMA memory unmapping functions.
 */
void
bus_dmamem_unmap(bus_dma_tag_t t, void *kva, size_t size)
{

#ifdef DIAGNOSTIC
	if ((vaddr_t)kva & PGOFSET)
		panic("%s", __func__);
#endif

	size = round_page(size);

	pmap_remove(pmap_kernel(), (vaddr_t)kva, (vaddr_t)kva + size);
	pmap_update(pmap_kernel());
	uvm_km_free(kernel_map, (vaddr_t)kva, size, UVM_KMF_VAONLY);
}

/*
 * Common function for mmap(2)'ing DMA-safe memory.  May be called by
 * bus-specific DMA mmap(2)'ing functions.
 */
paddr_t
bus_dmamem_mmap(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs, off_t off,
    int prot, int flags)
{
	int i, offset;

	offset = t->_displacement;

	for (i = 0; i < nsegs; i++) {
#ifdef DIAGNOSTIC
		if ((off & PGOFSET) != 0)
			panic("%s: offset unaligned", __func__);
		if ((segs[i].ds_addr & PGOFSET) != 0)
			panic("%s: segment unaligned", __func__);
		if ((segs[i].ds_len & PGOFSET) != 0)
			panic("%s: segment size not multiple of page size",
			    __func__);
#endif
		if (off >= segs[i].ds_len) {
			off -= segs[i].ds_len;
			continue;
		}

		return m68k_btop((char *)segs[i].ds_addr - offset + off);
	}

	/* Page not found. */
	return -1;
}

/**********************************************************************
 * DMA utility functions
 **********************************************************************/

/*
 * Utility function to load a linear buffer.  lastaddrp holds state
 * between invocations (for multiple-buffer loads).  segp contains
 * the starting segment on entrance, and the ending segment on exit.
 * first indicates if this is the first invocation of this function.
 */
static int
_bus_dmamap_load_buffer(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
    bus_size_t buflen, struct vmspace *vm, int flags, paddr_t *lastaddrp,
    int *segp, int first)
{
	bus_size_t sgsize;
	bus_addr_t curaddr, lastaddr, offset, baddr, bmask;
	vaddr_t vaddr = (vaddr_t)buf;
	int seg;
	pmap_t pmap;

	offset = t->_displacement;

	pmap = vm_map_pmap(&vm->vm_map);

	lastaddr = *lastaddrp;
	bmask = ~(map->_dm_boundary - 1);

	for (seg = *segp; buflen > 0 ; ) {
		/*
		 * Get the physical address for this segment.
		 */
		(void)pmap_extract(pmap, vaddr, &curaddr);

		/*
		 * Compute the segment size, and adjust counts.
		 */
		sgsize = PAGE_SIZE - ((vaddr_t)vaddr & PGOFSET);
		if (buflen < sgsize)
			sgsize = buflen;

		/*
		 * Make sure we don't cross any boundaries.
		 */
		if (map->_dm_boundary > 0) {
			baddr = (curaddr + map->_dm_boundary) & bmask;
			if (sgsize > (baddr - curaddr))
				sgsize = (baddr - curaddr);
		}

		/*
		 * Insert chunk into a segment, coalescing with
		 * previous segment if possible.
		 */
		if (first) {
			map->dm_segs[seg].ds_addr = curaddr + offset;
			map->dm_segs[seg].ds_len = sgsize;
			first = 0;
		} else {
			if (curaddr == lastaddr &&
			    (map->dm_segs[seg].ds_len + sgsize) <=
			     map->dm_maxsegsz &&
			    (map->_dm_boundary == 0 ||
			     (map->dm_segs[seg].ds_addr & bmask) ==
			     (curaddr & bmask)))
				map->dm_segs[seg].ds_len += sgsize;
			else {
				if (++seg >= map->_dm_segcnt)
					break;
				map->dm_segs[seg].ds_addr = curaddr + offset;
				map->dm_segs[seg].ds_len = sgsize;
			}
		}

		lastaddr = curaddr + sgsize;
		vaddr += sgsize;
		buflen -= sgsize;
	}

	*segp = seg;
	*lastaddrp = lastaddr;

	/*
	 * Did we fit?
	 */
	if (buflen != 0)
		return EFBIG;		/* XXX better return value here? */
	return 0;
}

/*
 * Allocate physical memory from the given physical address range.
 * Called by DMA-safe memory allocation methods.
 */
int
bus_dmamem_alloc_range(bus_dma_tag_t t, bus_size_t size, bus_size_t alignment,
    bus_size_t boundary, bus_dma_segment_t *segs, int nsegs, int *rsegs,
    int flags, paddr_t low, paddr_t high)
{
	paddr_t curaddr, lastaddr;
	bus_addr_t offset;
	struct vm_page *m;
	struct pglist mlist;
	int curseg, error;

	offset = t->_displacement;

	/* Always round the size. */
	size = round_page(size);

	/*
	 * Allocate pages from the VM system.
	 */
	error = uvm_pglistalloc(size, low, high, alignment, boundary,
	    &mlist, nsegs, (flags & BUS_DMA_NOWAIT) == 0);
	if (error != 0)
		return error;

	/*
	 * Compute the location, size, and number of segments actually
	 * returned by the VM code.
	 */
	m = TAILQ_FIRST(&mlist);
	curseg = 0;
	lastaddr = VM_PAGE_TO_PHYS(m);
	segs[curseg].ds_addr = lastaddr + offset;
	segs[curseg].ds_len = PAGE_SIZE;
	m = TAILQ_NEXT(m, pageq.queue);

	for (; m != NULL; m = TAILQ_NEXT(m, pageq.queue)) {
		curaddr = VM_PAGE_TO_PHYS(m);
#ifdef DIAGNOSTIC
		if (curaddr < low || curaddr >= high) {
			printf("uvm_pglistalloc returned non-sensical"
			    " address 0x%lx\n", curaddr);
			panic("%s", __func__);
		}
#endif
		if (curaddr == (lastaddr + PAGE_SIZE))
			segs[curseg].ds_len += PAGE_SIZE;
		else {
			curseg++;
			segs[curseg].ds_addr = curaddr + offset;
			segs[curseg].ds_len = PAGE_SIZE;
		}
		lastaddr = curaddr;
	}

	*rsegs = curseg + 1;

	return 0;
}