/*      $NetBSD: bus.c,v 1.71 2025/11/29 19:34:20 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 1.71 2025/11/29 19:34:20 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.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_BESTFIT | 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;
}