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[netbsd-mini2440.git] / sys / arch / arm / arm32 / bus_dma.c

/*      $NetBSD: bus_dma.c,v 1.51 2008/04/28 20:23:13 martin Exp $      */

/*-
 * Copyright (c) 1996, 1997, 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.
 *
 * 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.
 */

#define _ARM32_BUS_DMA_PRIVATE

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.51 2008/04/28 20:23:13 martin Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/reboot.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/vnode.h>
#include <sys/device.h>

#include <uvm/uvm_extern.h>

#include <machine/bus.h>
#include <machine/cpu.h>

#include <arm/cpufunc.h>

int     _bus_dmamap_load_buffer(bus_dma_tag_t, bus_dmamap_t, void *,
            bus_size_t, struct vmspace *, int);
struct arm32_dma_range *_bus_dma_inrange(struct arm32_dma_range *,
            int, bus_addr_t);

/*
 * Check to see if the specified page is in an allowed DMA range.
 */
inline struct arm32_dma_range *
_bus_dma_inrange(struct arm32_dma_range *ranges, int nranges,
    bus_addr_t curaddr)
{
        struct arm32_dma_range *dr;
        int i;

        for (i = 0, dr = ranges; i < nranges; i++, dr++) {
                if (curaddr >= dr->dr_sysbase &&
                    round_page(curaddr) <= (dr->dr_sysbase + dr->dr_len))
                        return (dr);
        }

        return (NULL);
}

/*
 * Common function to load the specified physical address into the
 * DMA map, coalescing segments and boundary checking as necessary.
 */
static int
_bus_dmamap_load_paddr(bus_dma_tag_t t, bus_dmamap_t map,
    bus_addr_t paddr, bus_size_t size)
{
        bus_dma_segment_t * const segs = map->dm_segs;
        int nseg = map->dm_nsegs;
        bus_addr_t lastaddr = 0xdead;   /* XXX gcc */
        bus_addr_t bmask = ~(map->_dm_boundary - 1);
        bus_addr_t curaddr;
        bus_size_t sgsize;

        if (nseg > 0)
                lastaddr = segs[nseg-1].ds_addr + segs[nseg-1].ds_len;
 again:
        sgsize = size;

        /* Make sure we're in an allowed DMA range. */
        if (t->_ranges != NULL) {
                /* XXX cache last result? */
                const struct arm32_dma_range * const dr =
                    _bus_dma_inrange(t->_ranges, t->_nranges, paddr);
                if (dr == NULL)
                        return (EINVAL);
                
                /*
                 * In a valid DMA range.  Translate the physical
                 * memory address to an address in the DMA window.
                 */
                curaddr = (paddr - dr->dr_sysbase) + dr->dr_busbase;
        } else
                curaddr = paddr;

        /*
         * Make sure we don't cross any boundaries.
         */
        if (map->_dm_boundary > 0) {
                bus_addr_t baddr;       /* next boundary address */

                baddr = (curaddr + map->_dm_boundary) & bmask;
                if (sgsize > (baddr - curaddr))
                        sgsize = (baddr - curaddr);
        }

        /*
         * Insert chunk into a segment, coalescing with the
         * previous segment if possible.
         */
        if (nseg > 0 && curaddr == lastaddr &&
            segs[nseg-1].ds_len + sgsize <= map->dm_maxsegsz &&
            (map->_dm_boundary == 0 ||
             (segs[nseg-1].ds_addr & bmask) == (curaddr & bmask))) {
                /* coalesce */
                segs[nseg-1].ds_len += sgsize;
        } else if (nseg >= map->_dm_segcnt) {
                return (EFBIG);
        } else {
                /* new segment */
                segs[nseg].ds_addr = curaddr;
                segs[nseg].ds_len = sgsize;
                nseg++;
        }

        lastaddr = curaddr + sgsize;

        paddr += sgsize;
        size -= sgsize;
        if (size > 0)
                goto again;
        
        map->dm_nsegs = nseg;
        return (0);
}

/*
 * 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 arm32_bus_dmamap *map;
        void *mapstore;
        size_t mapsize;

#ifdef DEBUG_DMA
        printf("dmamap_create: t=%p size=%lx nseg=%x msegsz=%lx boundary=%lx flags=%x\n",
            t, size, nsegments, maxsegsz, boundary, flags);
#endif  /* DEBUG_DMA */

        /*
         * 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).
         */
        mapsize = sizeof(struct arm32_bus_dmamap) +
            (sizeof(bus_dma_segment_t) * (nsegments - 1));
        if ((mapstore = malloc(mapsize, M_DMAMAP,
            (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK)) == NULL)
                return (ENOMEM);

        memset(mapstore, 0, mapsize);
        map = (struct arm32_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_origbuf = NULL;
        map->_dm_buftype = ARM32_BUFTYPE_INVALID;
        map->_dm_vmspace = vmspace_kernel();
        map->dm_maxsegsz = maxsegsz;
        map->dm_mapsize = 0;            /* no valid mappings */
        map->dm_nsegs = 0;

        *dmamp = map;
#ifdef DEBUG_DMA
        printf("dmamap_create:map=%p\n", map);
#endif  /* DEBUG_DMA */
        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)
{

#ifdef DEBUG_DMA
        printf("dmamap_destroy: t=%p map=%p\n", t, map);
#endif  /* DEBUG_DMA */

        /*
         * Explicit unload.
         */
        map->dm_maxsegsz = map->_dm_maxmaxsegsz;
        map->dm_mapsize = 0;
        map->dm_nsegs = 0;
        map->_dm_origbuf = NULL;
        map->_dm_buftype = ARM32_BUFTYPE_INVALID;
        map->_dm_vmspace = NULL;

        free(map, M_DMAMAP);
}

/*
 * 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)
{
        int error;
        struct vmspace *vm;

#ifdef DEBUG_DMA
        printf("dmamap_load: t=%p map=%p buf=%p len=%lx p=%p f=%d\n",
            t, map, buf, buflen, p, flags);
#endif  /* DEBUG_DMA */

        /*
         * 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();
        }

        /* _bus_dmamap_load_buffer() clears this if we're not... */
        map->_dm_flags |= ARM32_DMAMAP_COHERENT;

        error = _bus_dmamap_load_buffer(t, map, buf, buflen, vm, flags);
        if (error == 0) {
                map->dm_mapsize = buflen;
                map->_dm_origbuf = buf;
                map->_dm_buftype = ARM32_BUFTYPE_LINEAR;
                map->_dm_vmspace = vm;
        }
#ifdef DEBUG_DMA
        printf("dmamap_load: error=%d\n", error);
#endif  /* DEBUG_DMA */
        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)
{
        int error;
        struct mbuf *m;

#ifdef DEBUG_DMA
        printf("dmamap_load_mbuf: t=%p map=%p m0=%p f=%d\n",
            t, map, m0, flags);
#endif  /* DEBUG_DMA */

        /*
         * 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("_bus_dmamap_load_mbuf: no packet header");
#endif  /* DIAGNOSTIC */

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

        /*
         * Mbuf chains should almost never have coherent (i.e.
         * un-cached) mappings, so clear that flag now.
         */
        map->_dm_flags &= ~ARM32_DMAMAP_COHERENT;

        error = 0;
        for (m = m0; m != NULL && error == 0; m = m->m_next) {
                int offset;
                int remainbytes;
                const struct vm_page * const *pgs;
                paddr_t paddr;
                int size;

                if (m->m_len == 0)
                        continue;
                switch (m->m_flags & (M_EXT|M_CLUSTER|M_EXT_PAGES)) {
                case M_EXT|M_CLUSTER:
                        /* XXX KDASSERT */
                        KASSERT(m->m_ext.ext_paddr != M_PADDR_INVALID);
                        paddr = m->m_ext.ext_paddr +
                            (m->m_data - m->m_ext.ext_buf);
                        size = m->m_len;
                        error = _bus_dmamap_load_paddr(t, map, paddr, size);
                        break;
                
                case M_EXT|M_EXT_PAGES:
                        KASSERT(m->m_ext.ext_buf <= m->m_data);
                        KASSERT(m->m_data <=
                            m->m_ext.ext_buf + m->m_ext.ext_size);
                        
                        offset = (vaddr_t)m->m_data -
                            trunc_page((vaddr_t)m->m_ext.ext_buf);
                        remainbytes = m->m_len;

                        /* skip uninteresting pages */
                        pgs = (const struct vm_page * const *)
                            m->m_ext.ext_pgs + (offset >> PAGE_SHIFT);
                        
                        offset &= PAGE_MASK;    /* offset in the first page */

                        /* load each page */
                        while (remainbytes > 0) {
                                const struct vm_page *pg;

                                size = MIN(remainbytes, PAGE_SIZE - offset);

                                pg = *pgs++;
                                KASSERT(pg);
                                paddr = VM_PAGE_TO_PHYS(pg) + offset;

                                error = _bus_dmamap_load_paddr(t, map,
                                    paddr, size);
                                if (error)
                                        break;
                                offset = 0;
                                remainbytes -= size;
                        }
                        break;

                case 0:
                        paddr = m->m_paddr + M_BUFOFFSET(m) +
                            (m->m_data - M_BUFADDR(m));
                        size = m->m_len;
                        error = _bus_dmamap_load_paddr(t, map, paddr, size);
                        break;

                default:
                        error = _bus_dmamap_load_buffer(t, map, m->m_data,
                            m->m_len, vmspace_kernel(), flags);
                }
        }
        if (error == 0) {
                map->dm_mapsize = m0->m_pkthdr.len;
                map->_dm_origbuf = m0;
                map->_dm_buftype = ARM32_BUFTYPE_MBUF;
                map->_dm_vmspace = vmspace_kernel();    /* always kernel */
        }
#ifdef DEBUG_DMA
        printf("dmamap_load_mbuf: error=%d\n", error);
#endif  /* DEBUG_DMA */
        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)
{
        int i, error;
        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;

        /* _bus_dmamap_load_buffer() clears this if we're not... */
        map->_dm_flags |= ARM32_DMAMAP_COHERENT;

        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);

                resid -= minlen;
        }
        if (error == 0) {
                map->dm_mapsize = uio->uio_resid;
                map->_dm_origbuf = uio;
                map->_dm_buftype = ARM32_BUFTYPE_UIO;
                map->_dm_vmspace = uio->uio_vmspace;
        }
        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("_bus_dmamap_load_raw: not implemented");
}

/*
 * 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)
{

#ifdef DEBUG_DMA
        printf("dmamap_unload: t=%p map=%p\n", t, map);
#endif  /* DEBUG_DMA */

        /*
         * No resources to free; just mark the mappings as
         * invalid.
         */
        map->dm_mapsize = 0;
        map->dm_nsegs = 0;
        map->_dm_origbuf = NULL;
        map->_dm_buftype = ARM32_BUFTYPE_INVALID;
        map->_dm_vmspace = NULL;
}

static inline void
_bus_dmamap_sync_linear(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{
        vaddr_t addr = (vaddr_t) map->_dm_origbuf;

        addr += offset;

        switch (ops) {
        case BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE:
                cpu_dcache_wbinv_range(addr, len);
                break;

        case BUS_DMASYNC_PREREAD:
                if (((addr | len) & arm_dcache_align_mask) == 0)
                        cpu_dcache_inv_range(addr, len);
                else
                        cpu_dcache_wbinv_range(addr, len);
                break;

        case BUS_DMASYNC_PREWRITE:
                cpu_dcache_wb_range(addr, len);
                break;
        }
}

static inline void
_bus_dmamap_sync_mbuf(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{
        struct mbuf *m, *m0 = map->_dm_origbuf;
        bus_size_t minlen, moff;
        vaddr_t maddr;

        for (moff = offset, m = m0; m != NULL && len != 0; m = m->m_next) {
                /* Find the beginning mbuf. */
                if (moff >= m->m_len) {
                        moff -= m->m_len;
                        continue;
                }

                /*
                 * Now at the first mbuf to sync; nail each one until
                 * we have exhausted the length.
                 */
                minlen = m->m_len - moff;
                if (len < minlen)
                        minlen = len;

                maddr = mtod(m, vaddr_t);
                maddr += moff;

                /*
                 * We can save a lot of work here if we know the mapping
                 * is read-only at the MMU:
                 *
                 * If a mapping is read-only, no dirty cache blocks will
                 * exist for it.  If a writable mapping was made read-only,
                 * we know any dirty cache lines for the range will have
                 * been cleaned for us already.  Therefore, if the upper
                 * layer can tell us we have a read-only mapping, we can
                 * skip all cache cleaning.
                 *
                 * NOTE: This only works if we know the pmap cleans pages
                 * before making a read-write -> read-only transition.  If
                 * this ever becomes non-true (e.g. Physically Indexed
                 * cache), this will have to be revisited.
                 */
                switch (ops) {
                case BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE:
                        if (! M_ROMAP(m)) {
                                cpu_dcache_wbinv_range(maddr, minlen);
                                break;
                        }
                        /* else FALLTHROUGH */

                case BUS_DMASYNC_PREREAD:
                        if (((maddr | minlen) & arm_dcache_align_mask) == 0)
                                cpu_dcache_inv_range(maddr, minlen);
                        else
                                cpu_dcache_wbinv_range(maddr, minlen);
                        break;

                case BUS_DMASYNC_PREWRITE:
                        if (! M_ROMAP(m))
                                cpu_dcache_wb_range(maddr, minlen);
                        break;
                }
                moff = 0;
                len -= minlen;
        }
}

static inline void
_bus_dmamap_sync_uio(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{
        struct uio *uio = map->_dm_origbuf;
        struct iovec *iov;
        bus_size_t minlen, ioff;
        vaddr_t addr;

        for (iov = uio->uio_iov, ioff = offset; len != 0; iov++) {
                /* Find the beginning iovec. */
                if (ioff >= iov->iov_len) {
                        ioff -= iov->iov_len;
                        continue;
                }

                /*
                 * Now at the first iovec to sync; nail each one until
                 * we have exhausted the length.
                 */
                minlen = iov->iov_len - ioff;
                if (len < minlen)
                        minlen = len;

                addr = (vaddr_t) iov->iov_base;
                addr += ioff;

                switch (ops) {
                case BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE:
                        cpu_dcache_wbinv_range(addr, minlen);
                        break;

                case BUS_DMASYNC_PREREAD:
                        if (((addr | minlen) & arm_dcache_align_mask) == 0)
                                cpu_dcache_inv_range(addr, minlen);
                        else
                                cpu_dcache_wbinv_range(addr, minlen);
                        break;

                case BUS_DMASYNC_PREWRITE:
                        cpu_dcache_wb_range(addr, minlen);
                        break;
                }
                ioff = 0;
                len -= minlen;
        }
}

/*
 * Common function for DMA map synchronization.  May be called
 * by bus-specific DMA map synchronization functions.
 *
 * This version works for the Virtually Indexed Virtually Tagged
 * cache found on 32-bit ARM processors.
 *
 * XXX Should have separate versions for write-through vs.
 * XXX write-back caches.  We currently assume write-back
 * XXX here, which is not as efficient as it could be for
 * XXX the write-through case.
 */
void
_bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{

#ifdef DEBUG_DMA
        printf("dmamap_sync: t=%p map=%p offset=%lx len=%lx ops=%x\n",
            t, map, offset, len, ops);
#endif  /* DEBUG_DMA */

        /*
         * Mixing of PRE and POST operations is not allowed.
         */
        if ((ops & (BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE)) != 0 &&
            (ops & (BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE)) != 0)
                panic("_bus_dmamap_sync: mix PRE and POST");

#ifdef DIAGNOSTIC
        if (offset >= map->dm_mapsize)
                panic("_bus_dmamap_sync: bad offset %lu (map size is %lu)",
                    offset, map->dm_mapsize);
        if (len == 0 || (offset + len) > map->dm_mapsize)
                panic("_bus_dmamap_sync: bad length");
#endif

        /*
         * For a virtually-indexed write-back cache, we need
         * to do the following things:
         *
         *      PREREAD -- Invalidate the D-cache.  We do this
         *      here in case a write-back is required by the back-end.
         *
         *      PREWRITE -- Write-back the D-cache.  Note that if
         *      we are doing a PREREAD|PREWRITE, we can collapse
         *      the whole thing into a single Wb-Inv.
         *
         *      POSTREAD -- Nothing.
         *
         *      POSTWRITE -- Nothing.
         */

        ops &= (BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);
        if (ops == 0)
                return;

        /* Skip cache frobbing if mapping was COHERENT. */
        if (map->_dm_flags & ARM32_DMAMAP_COHERENT) {
                /* Drain the write buffer. */
                cpu_drain_writebuf();
                return;
        }

        /*
         * If the mapping belongs to a non-kernel vmspace, and the
         * vmspace has not been active since the last time a full
         * cache flush was performed, we don't need to do anything.
         */
        if (__predict_false(!VMSPACE_IS_KERNEL_P(map->_dm_vmspace) &&
            vm_map_pmap(&map->_dm_vmspace->vm_map)->pm_cstate.cs_cache_d == 0))
                return;

        switch (map->_dm_buftype) {
        case ARM32_BUFTYPE_LINEAR:
                _bus_dmamap_sync_linear(t, map, offset, len, ops);
                break;

        case ARM32_BUFTYPE_MBUF:
                _bus_dmamap_sync_mbuf(t, map, offset, len, ops);
                break;

        case ARM32_BUFTYPE_UIO:
                _bus_dmamap_sync_uio(t, map, offset, len, ops);
                break;

        case ARM32_BUFTYPE_RAW:
                panic("_bus_dmamap_sync: ARM32_BUFTYPE_RAW");
                break;

        case ARM32_BUFTYPE_INVALID:
                panic("_bus_dmamap_sync: ARM32_BUFTYPE_INVALID");
                break;

        default:
                printf("unknown buffer type %d\n", map->_dm_buftype);
                panic("_bus_dmamap_sync");
        }

        /* Drain the write buffer. */
        cpu_drain_writebuf();
}

/*
 * Common function for DMA-safe memory allocation.  May be called
 * by bus-specific DMA memory allocation functions.
 */

extern paddr_t physical_start;
extern paddr_t physical_end;

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)
{
        struct arm32_dma_range *dr;
        int error, i;

#ifdef DEBUG_DMA
        printf("dmamem_alloc t=%p size=%lx align=%lx boundary=%lx "
            "segs=%p nsegs=%x rsegs=%p flags=%x\n", t, size, alignment,
            boundary, segs, nsegs, rsegs, flags);
#endif

        if ((dr = t->_ranges) != NULL) {
                error = ENOMEM;
                for (i = 0; i < t->_nranges; i++, dr++) {
                        if (dr->dr_len == 0)
                                continue;
                        error = _bus_dmamem_alloc_range(t, size, alignment,
                            boundary, segs, nsegs, rsegs, flags,
                            trunc_page(dr->dr_sysbase),
                            trunc_page(dr->dr_sysbase + dr->dr_len));
                        if (error == 0)
                                break;
                }
        } else {
                error = _bus_dmamem_alloc_range(t, size, alignment, boundary,
                    segs, nsegs, rsegs, flags, trunc_page(physical_start),
                    trunc_page(physical_end));
        }

#ifdef DEBUG_DMA
        printf("dmamem_alloc: =%d\n", error);
#endif

        return(error);
}

/*
 * 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;
        struct pglist mlist;
        int curseg;

#ifdef DEBUG_DMA
        printf("dmamem_free: t=%p segs=%p nsegs=%x\n", t, segs, nsegs);
#endif  /* DEBUG_DMA */

        /*
         * 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);
                        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;
        int curseg;
        pt_entry_t *ptep/*, pte*/;
        const uvm_flag_t kmflags =
            (flags & BUS_DMA_NOWAIT) != 0 ? UVM_KMF_NOWAIT : 0;

#ifdef DEBUG_DMA
        printf("dmamem_map: t=%p segs=%p nsegs=%x size=%lx flags=%x\n", t,
            segs, nsegs, (unsigned long)size, flags);
#endif  /* DEBUG_DMA */

        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) {
#ifdef DEBUG_DMA
                        printf("wiring p%lx to v%lx", addr, va);
#endif  /* DEBUG_DMA */
                        if (size == 0)
                                panic("_bus_dmamem_map: size botch");
                        pmap_enter(pmap_kernel(), va, addr,
                            VM_PROT_READ | VM_PROT_WRITE,
                            VM_PROT_READ | VM_PROT_WRITE | PMAP_WIRED);
                        /*
                         * If the memory must remain coherent with the
                         * cache then we must make the memory uncacheable
                         * in order to maintain virtual cache coherency.
                         * We must also guarantee the cache does not already
                         * contain the virtal addresses we are making
                         * uncacheable.
                         */
                        if (flags & BUS_DMA_COHERENT) {
                                cpu_dcache_wbinv_range(va, PAGE_SIZE);
                                cpu_drain_writebuf();
                                ptep = vtopte(va);
                                *ptep &= ~L2_S_CACHE_MASK;
                                PTE_SYNC(ptep);
                                tlb_flush();
                        }
#ifdef DEBUG_DMA
                        ptep = vtopte(va);
                        printf(" pte=v%p *pte=%x\n", ptep, *ptep);
#endif  /* DEBUG_DMA */
                }
        }
        pmap_update(pmap_kernel());
#ifdef DEBUG_DMA
        printf("dmamem_map: =%p\n", *kvap);
#endif  /* DEBUG_DMA */
        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 DEBUG_DMA
        printf("dmamem_unmap: t=%p kva=%p size=%lx\n", t, kva,
            (unsigned long)size);
#endif  /* DEBUG_DMA */
#ifdef DIAGNOSTIC
        if ((u_long)kva & PGOFSET)
                panic("_bus_dmamem_unmap");
#endif  /* DIAGNOSTIC */

        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 functin 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;

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

                return (arm_btop((u_long)segs[i].ds_addr + 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 entrace, and the ending segment on exit.
 * first indicates if this is the first invocation of this function.
 */
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)
{
        bus_size_t sgsize;
        bus_addr_t curaddr;
        vaddr_t vaddr = (vaddr_t)buf;
        pd_entry_t *pde;
        pt_entry_t pte;
        int error;
        pmap_t pmap;
        pt_entry_t *ptep;

#ifdef DEBUG_DMA
        printf("_bus_dmamem_load_buffer(buf=%p, len=%lx, flags=%d)\n",
            buf, buflen, flags);
#endif  /* DEBUG_DMA */

        pmap = vm_map_pmap(&vm->vm_map);

        while (buflen > 0) {
                /*
                 * Get the physical address for this segment.
                 *
                 * XXX Don't support checking for coherent mappings
                 * XXX in user address space.
                 */
                if (__predict_true(pmap == pmap_kernel())) {
                        (void) pmap_get_pde_pte(pmap, vaddr, &pde, &ptep);
                        if (__predict_false(pmap_pde_section(pde))) {
                                curaddr = (*pde & L1_S_FRAME) |
                                    (vaddr & L1_S_OFFSET);
                                if (*pde & L1_S_CACHE_MASK) {
                                        map->_dm_flags &=
                                            ~ARM32_DMAMAP_COHERENT;
                                }
                        } else {
                                pte = *ptep;
                                KDASSERT((pte & L2_TYPE_MASK) != L2_TYPE_INV);
                                if (__predict_false((pte & L2_TYPE_MASK)
                                                    == L2_TYPE_L)) {
                                        curaddr = (pte & L2_L_FRAME) |
                                            (vaddr & L2_L_OFFSET);
                                        if (pte & L2_L_CACHE_MASK) {
                                                map->_dm_flags &=
                                                    ~ARM32_DMAMAP_COHERENT;
                                        }
                                } else {
                                        curaddr = (pte & L2_S_FRAME) |
                                            (vaddr & L2_S_OFFSET);
                                        if (pte & L2_S_CACHE_MASK) {
                                                map->_dm_flags &=
                                                    ~ARM32_DMAMAP_COHERENT;
                                        }
                                }
                        }
                } else {
                        (void) pmap_extract(pmap, vaddr, &curaddr);
                        map->_dm_flags &= ~ARM32_DMAMAP_COHERENT;
                }

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

                error = _bus_dmamap_load_paddr(t, map, curaddr, sgsize);
                if (error)
                        return (error);

                vaddr += sgsize;
                buflen -= sgsize;
        }

        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;
        struct vm_page *m;
        struct pglist mlist;
        int curseg, error;

#ifdef DEBUG_DMA
        printf("alloc_range: t=%p size=%lx align=%lx boundary=%lx segs=%p nsegs=%x rsegs=%p flags=%x lo=%lx hi=%lx\n",
            t, size, alignment, boundary, segs, nsegs, rsegs, flags, low, high);
#endif  /* DEBUG_DMA */

        /* 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)
                return (error);

        /*
         * Compute the location, size, and number of segments actually
         * returned by the VM code.
         */
        m = TAILQ_FIRST(&mlist);
        curseg = 0;
        lastaddr = segs[curseg].ds_addr = VM_PAGE_TO_PHYS(m);
        segs[curseg].ds_len = PAGE_SIZE;
#ifdef DEBUG_DMA
                printf("alloc: page %lx\n", lastaddr);
#endif  /* DEBUG_DMA */
        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("_bus_dmamem_alloc_range");
                }
#endif  /* DIAGNOSTIC */
#ifdef DEBUG_DMA
                printf("alloc: page %lx\n", curaddr);
#endif  /* DEBUG_DMA */
                if (curaddr == (lastaddr + PAGE_SIZE))
                        segs[curseg].ds_len += PAGE_SIZE;
                else {
                        curseg++;
                        segs[curseg].ds_addr = curaddr;
                        segs[curseg].ds_len = PAGE_SIZE;
                }
                lastaddr = curaddr;
        }

        *rsegs = curseg + 1;

        return (0);
}

/*
 * Check if a memory region intersects with a DMA range, and return the
 * page-rounded intersection if it does.
 */
int
arm32_dma_range_intersect(struct arm32_dma_range *ranges, int nranges,
    paddr_t pa, psize_t size, paddr_t *pap, psize_t *sizep)
{
        struct arm32_dma_range *dr;
        int i;

        if (ranges == NULL)
                return (0);

        for (i = 0, dr = ranges; i < nranges; i++, dr++) {
                if (dr->dr_sysbase <= pa &&
                    pa < (dr->dr_sysbase + dr->dr_len)) {
                        /*
                         * Beginning of region intersects with this range.
                         */
                        *pap = trunc_page(pa);
                        *sizep = round_page(min(pa + size,
                            dr->dr_sysbase + dr->dr_len) - pa);
                        return (1);
                }
                if (pa < dr->dr_sysbase && dr->dr_sysbase < (pa + size)) {
                        /*
                         * End of region intersects with this range.
                         */
                        *pap = trunc_page(dr->dr_sysbase);
                        *sizep = round_page(min((pa + size) - dr->dr_sysbase,
                            dr->dr_len));
                        return (1);
                }
        }

        /* No intersection found. */
        return (0);
}