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[haiku.git] / src / libs / compat / freebsd_network / fbsd_busdma_x86.c

/*-
 * Copyright (c) 1997, 1998 Justin T. Gibbs.
 * All rights reserved.
 *
 * 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,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/i386/i386/busdma_machdep.c,v 1.74.2.4 2006/10/21 16:26:53 hrs Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/mbuf.h>
#include <sys/uio.h>
#include <sys/sysctl.h>

#include <vm/vm.h>

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

#ifdef __x86_64__
#       define MAX_BPAGES 8192
#else
#       define MAX_BPAGES 512
#endif

/* -hugo */
#define malloc(a, b, c)                                         kernel_malloc(a, b, c)
#define free(a, b)                                                      kernel_free(a, b)
#define contigmalloc(a, b, c, d, e, f, g)       kernel_contigmalloc(a, b, c, d, e, f, g)
#define contigfree(a, b, c)                                     kernel_contigfree(a, b, c)
void busdma_swi(void);
void init_bounce_pages(void);
void uninit_bounce_pages(void);
/* </> */

struct bounce_zone;

struct bus_dma_tag {
        bus_dma_tag_t     parent;
        bus_size_t        alignment;
        bus_addr_t        boundary;
        bus_addr_t        lowaddr;
        bus_addr_t        highaddr;
        bus_dma_filter_t *filter;
        void             *filterarg;
        bus_size_t        maxsize;
        u_int             nsegments;
        bus_size_t        maxsegsz;
        int               flags;
        int               ref_count;
        int               map_count;
        bus_dma_lock_t   *lockfunc;
        void             *lockfuncarg;
        bus_dma_segment_t *segments;
        struct bounce_zone *bounce_zone;
};

struct bounce_page {
        vm_offset_t     vaddr;          /* kva of bounce buffer */
        bus_addr_t      busaddr;        /* Physical address */
        vm_offset_t     datavaddr;      /* kva of client data */
        bus_size_t      datacount;      /* client data count */
        STAILQ_ENTRY(bounce_page) links;
};

int busdma_swi_pending;

struct bounce_zone {
        STAILQ_ENTRY(bounce_zone) links;
        STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
        int             total_bpages;
        int             free_bpages;
        int             reserved_bpages;
        int             active_bpages;
        int             total_bounced;
        int             total_deferred;
        bus_size_t      alignment;
        bus_addr_t      boundary;
        bus_addr_t      lowaddr;
        char            zoneid[8];
        char            lowaddrid[20];
        struct sysctl_ctx_list sysctl_tree;
        struct sysctl_oid *sysctl_tree_top;
};

static struct mtx bounce_lock;
static int total_bpages;
static int busdma_zonecount;
static STAILQ_HEAD(, bounce_zone) bounce_zone_list;

SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
           "Total bounce pages");

struct bus_dmamap {
        struct bp_list         bpages;
        int                    pagesneeded;
        int                    pagesreserved;
        bus_dma_tag_t          dmat;
        void                  *buf;             /* unmapped buffer pointer */
        bus_size_t             buflen;          /* unmapped buffer length */
        bus_dmamap_callback_t *callback;
        void                  *callback_arg;
        STAILQ_ENTRY(bus_dmamap) links;
};

static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
static struct bus_dmamap nobounce_dmamap;

static int alloc_bounce_zone(bus_dma_tag_t dmat);
static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
                                int commit);
static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
                                   vm_offset_t vaddr, bus_size_t size);
static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);

/*
 * Return true if a match is made.
 *
 * To find a match walk the chain of bus_dma_tag_t's looking for 'paddr'.
 *
 * If paddr is within the bounds of the dma tag then call the filter callback
 * to check for a match, if there is no filter callback then assume a match.
 */
static __inline
int
run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
{
        int retval;

        retval = 0;

        do {
                if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr)
                 || ((paddr & (dmat->alignment - 1)) != 0))
                 && (dmat->filter == NULL
                  || (*dmat->filter)(dmat->filterarg, paddr) != 0))
                        retval = 1;

                dmat = dmat->parent;            
        } while (retval == 0 && dmat != NULL);
        return (retval);
}

/*
 * Convenience function for manipulating driver locks from busdma (during
 * busdma_swi, for example).  Drivers that don't provide their own locks
 * should specify &Giant to dmat->lockfuncarg.  Drivers that use their own
 * non-mutex locking scheme don't have to use this at all.
 */
void
busdma_lock_mutex(void *arg, bus_dma_lock_op_t op)
{
        struct mtx *dmtx;

        dmtx = (struct mtx *)arg;
        switch (op) {
        case BUS_DMA_LOCK:
                mtx_lock(dmtx);
                break;
        case BUS_DMA_UNLOCK:
                mtx_unlock(dmtx);
                break;
        default:
                panic("Unknown operation 0x%x for busdma_lock_mutex!", op);
        }
}

/*
 * dflt_lock should never get called.  It gets put into the dma tag when
 * lockfunc == NULL, which is only valid if the maps that are associated
 * with the tag are meant to never be defered.
 * XXX Should have a way to identify which driver is responsible here.
 */
static
void
dflt_lock(void *arg, bus_dma_lock_op_t op)
{
        panic("driver error: busdma dflt_lock called");
}

#define BUS_DMA_COULD_BOUNCE    BUS_DMA_BUS3
#define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4

/*
 * Allocate a device specific dma_tag.
 */
int
bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
                   bus_size_t boundary, bus_addr_t lowaddr,
                   bus_addr_t highaddr, bus_dma_filter_t *filter,
                   void *filterarg, bus_size_t maxsize, int nsegments,
                   bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
                   void *lockfuncarg, bus_dma_tag_t *dmat)
{
        bus_dma_tag_t newtag;
        int error = 0;

        /* Basic sanity checking */
        if (boundary != 0 && boundary < maxsegsz)
                maxsegsz = boundary;

        /* Return a NULL tag on failure */
        *dmat = NULL;

        newtag = (bus_dma_tag_t)malloc(sizeof(*newtag), M_DEVBUF,
            M_ZERO | M_NOWAIT);
        if (newtag == NULL) {
                CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
                    __func__, newtag, 0, error);
                return (ENOMEM);
        }

        newtag->parent = parent;
        newtag->alignment = alignment;
        newtag->boundary = boundary;
        newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
        newtag->highaddr = trunc_page((vm_paddr_t)highaddr) +
            (PAGE_SIZE - 1);
        newtag->filter = filter;
        newtag->filterarg = filterarg;
        newtag->maxsize = maxsize;
        newtag->nsegments = nsegments;
        newtag->maxsegsz = maxsegsz;
        newtag->flags = flags;
        newtag->ref_count = 1; /* Count ourself */
        newtag->map_count = 0;
        if (lockfunc != NULL) {
                newtag->lockfunc = lockfunc;
                newtag->lockfuncarg = lockfuncarg;
        } else {
                newtag->lockfunc = dflt_lock;
                newtag->lockfuncarg = NULL;
        }
        newtag->segments = NULL;

        /* Take into account any restrictions imposed by our parent tag */
        if (parent != NULL) {
                newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
                newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
                if (newtag->boundary == 0)
                        newtag->boundary = parent->boundary;
                else if (parent->boundary != 0)
                        newtag->boundary = MIN(parent->boundary,
                                               newtag->boundary);
                if (newtag->filter == NULL) {
                        /*
                         * Short circuit looking at our parent directly
                         * since we have encapsulated all of its information
                         */
                        newtag->filter = parent->filter;
                        newtag->filterarg = parent->filterarg;
                        newtag->parent = parent->parent;
                }
                if (newtag->parent != NULL)
                        atomic_add_int(&parent->ref_count, 1);
        }

        if (newtag->lowaddr < ptoa((vm_paddr_t)Maxmem)
         || newtag->alignment > 1)
                newtag->flags |= BUS_DMA_COULD_BOUNCE;

        if (((newtag->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
            (flags & BUS_DMA_ALLOCNOW) != 0) {
                struct bounce_zone *bz;

                /* Must bounce */

                if ((error = alloc_bounce_zone(newtag)) != 0) {
                        free(newtag, M_DEVBUF);
                        return (error);
                }
                bz = newtag->bounce_zone;

                if (ptoa(bz->total_bpages) < maxsize) {
                        int pages;

                        pages = atop(maxsize) - bz->total_bpages;

                        /* Add pages to our bounce pool */
                        if (alloc_bounce_pages(newtag, pages) < pages)
                                error = ENOMEM;
                }
                /* Performed initial allocation */
                newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
        }
        
        if (error != 0) {
                free(newtag, M_DEVBUF);
        } else {
                *dmat = newtag;
        }
        CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
            __func__, newtag, (newtag != NULL ? newtag->flags : 0), error);
        return (error);
}

int
bus_dma_tag_destroy(bus_dma_tag_t dmat)
{
        bus_dma_tag_t dmat_copy;
        int error;

        error = 0;
        dmat_copy = dmat;

        if (dmat != NULL) {

                if (dmat->map_count != 0) {
                        error = EBUSY;
                        goto out;
                }

                while (dmat != NULL) {
                        bus_dma_tag_t parent;

                        parent = dmat->parent;
                        atomic_subtract_int(&dmat->ref_count, 1);
                        if (dmat->ref_count == 0) {
                                if (dmat->segments != NULL)
                                        free(dmat->segments, M_DEVBUF);
                                free(dmat, M_DEVBUF);
                                /*
                                 * Last reference count, so
                                 * release our reference
                                 * count on our parent.
                                 */
                                dmat = parent;
                        } else
                                dmat = NULL;
                }
        }
out:
        CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
        return (error);
}

/*
 * Allocate a handle for mapping from kva/uva/physical
 * address space into bus device space.
 */
int
bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
{
        int error;

        error = 0;

        if (dmat->segments == NULL) {
                dmat->segments = (bus_dma_segment_t *)malloc(
                    sizeof(bus_dma_segment_t) * dmat->nsegments, M_DEVBUF,
                    M_NOWAIT);
                if (dmat->segments == NULL) {
                        CTR3(KTR_BUSDMA, "%s: tag %p error %d",
                            __func__, dmat, ENOMEM);
                        return (ENOMEM);
                }
        }

        /*
         * Bouncing might be required if the driver asks for an active
         * exclusion region, a data alignment that is stricter than 1, and/or
         * an active address boundary.
         */
        if (dmat->flags & BUS_DMA_COULD_BOUNCE) {

                /* Must bounce */
                struct bounce_zone *bz;
                int maxpages;

                if (dmat->bounce_zone == NULL) {
                        if ((error = alloc_bounce_zone(dmat)) != 0)
                                return (error);
                }
                bz = dmat->bounce_zone;

                *mapp = (bus_dmamap_t)malloc(sizeof(**mapp), M_DEVBUF,
                                             M_NOWAIT | M_ZERO);
                if (*mapp == NULL) {
                        CTR3(KTR_BUSDMA, "%s: tag %p error %d",
                            __func__, dmat, ENOMEM);
                        return (ENOMEM);
                }

                /* Initialize the new map */
                STAILQ_INIT(&((*mapp)->bpages));

                /*
                 * Attempt to add pages to our pool on a per-instance
                 * basis up to a sane limit.
                 */
                if (dmat->alignment > 1)
                        maxpages = MAX_BPAGES;
                else
                        maxpages = MIN(MAX_BPAGES, Maxmem -atop(dmat->lowaddr));
                if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
                 || (dmat->map_count > 0 && bz->total_bpages < maxpages)) {
                        int pages;

                        pages = MAX(atop(dmat->maxsize), 1);
                        pages = MIN(maxpages - bz->total_bpages, pages);
                        pages = MAX(pages, 1);
                        if (alloc_bounce_pages(dmat, pages) < pages)
                                error = ENOMEM;

                        if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
                                if (error == 0)
                                        dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
                        } else {
                                error = 0;
                        }
                }
        } else {
                *mapp = NULL;
        }
        if (error == 0)
                dmat->map_count++;
        CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
            __func__, dmat, dmat->flags, error);
        return (error);
}

/*
 * Destroy a handle for mapping from kva/uva/physical
 * address space into bus device space.
 */
int
bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
{
        if (map != NULL && map != &nobounce_dmamap) {
                if (STAILQ_FIRST(&map->bpages) != NULL) {
                        CTR3(KTR_BUSDMA, "%s: tag %p error %d",
                            __func__, dmat, EBUSY);
                        return (EBUSY);
                }
                free(map, M_DEVBUF);
        }
        dmat->map_count--;
        CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
        return (0);
}

/*
 * Allocate a piece of memory that can be efficiently mapped into
 * bus device space based on the constraints lited in the dma tag.
 * A dmamap to for use with dmamap_load is also allocated.
 */
int
bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
                 bus_dmamap_t *mapp)
{
        int mflags;

        if (flags & BUS_DMA_NOWAIT)
                mflags = M_NOWAIT;
        else
                mflags = M_WAITOK;
        if (flags & BUS_DMA_ZERO)
                mflags |= M_ZERO;

        /* If we succeed, no mapping/bouncing will be required */
        *mapp = NULL;

        if (dmat->segments == NULL) {
                dmat->segments = (bus_dma_segment_t *)malloc(
                    sizeof(bus_dma_segment_t) * dmat->nsegments, M_DEVBUF,
                    M_NOWAIT);
                if (dmat->segments == NULL) {
                        CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
                            __func__, dmat, dmat->flags, ENOMEM);
                        return (ENOMEM);
                }
        }

        /* 
         * XXX:
         * (dmat->alignment < dmat->maxsize) is just a quick hack; the exact
         * alignment guarantees of malloc need to be nailed down, and the
         * code below should be rewritten to take that into account.
         *
         * In the meantime, we'll warn the user if malloc gets it wrong.
         */
        if ((dmat->maxsize <= PAGE_SIZE) &&
           (dmat->alignment < dmat->maxsize) &&
            dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
                *vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
        } else {
                /*
                 * XXX Use Contigmalloc until it is merged into this facility
                 *     and handles multi-seg allocations.  Nobody is doing
                 *     multi-seg allocations yet though.
                 * XXX Certain AGP hardware does.
                 */
                *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
                    0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
                    dmat->boundary);
        }
        if (*vaddr == NULL) {
                CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
                    __func__, dmat, dmat->flags, ENOMEM);
                return (ENOMEM);
        } else if ((uintptr_t)*vaddr & (dmat->alignment - 1)) {
                printf("bus_dmamem_alloc failed to align memory properly.\n");
        }
        CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
            __func__, dmat, dmat->flags, 0);
        return (0);
}

/*
 * Free a piece of memory and it's allociated dmamap, that was allocated
 * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 */
void
bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
{
        /*
         * dmamem does not need to be bounced, so the map should be
         * NULL
         */
        if (map != NULL)
                panic("bus_dmamem_free: Invalid map freed\n");
        if ((dmat->maxsize <= PAGE_SIZE) &&
           (dmat->alignment < dmat->maxsize) &&
            dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
                free(vaddr, M_DEVBUF);
        else {
                contigfree(vaddr, dmat->maxsize, M_DEVBUF);
        }
        CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat, dmat->flags);
}

/*
 * 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.
 */
static __inline int
_bus_dmamap_load_buffer(bus_dma_tag_t dmat,
                        bus_dmamap_t map,
                        void *buf, bus_size_t buflen,
                        pmap_t pmap,
                        int flags,
                        bus_addr_t *lastaddrp,
                        bus_dma_segment_t *segs,
                        int *segp,
                        int first)
{
        bus_size_t sgsize;
        bus_addr_t curaddr, lastaddr, baddr, bmask;
        vm_offset_t vaddr;
        bus_addr_t paddr;
        int needbounce = 0;
        int seg;

        if (map == NULL)
                map = &nobounce_dmamap;

        if ((map != &nobounce_dmamap && map->pagesneeded == 0) 
         && ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0)) {
                vm_offset_t     vendaddr;

                CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
                    "alignment= %d", dmat->lowaddr, ptoa((vm_paddr_t)Maxmem),
                    dmat->boundary, dmat->alignment);
                CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
                    map, &nobounce_dmamap, map->pagesneeded);
                /*
                 * Count the number of bounce pages
                 * needed in order to complete this transfer
                 */
                vaddr = trunc_page((vm_offset_t)buf);
                vendaddr = (vm_offset_t)buf + buflen;

                while (vaddr < vendaddr) {
                        paddr = pmap_kextract(vaddr);
                        if (run_filter(dmat, paddr) != 0) {
                                needbounce = 1;
                                map->pagesneeded++;
                        }
                        vaddr += PAGE_SIZE;
                }
                CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
        }

        /* Reserve Necessary Bounce Pages */
        if (map->pagesneeded != 0) {
                mtx_lock(&bounce_lock);
                if (flags & BUS_DMA_NOWAIT) {
                        if (reserve_bounce_pages(dmat, map, 0) != 0) {
                                mtx_unlock(&bounce_lock);
                                return (ENOMEM);
                        }
                } else {
                        if (reserve_bounce_pages(dmat, map, 1) != 0) {
                                /* Queue us for resources */
                                map->dmat = dmat;
                                map->buf = buf;
                                map->buflen = buflen;
                                STAILQ_INSERT_TAIL(&bounce_map_waitinglist,
                                    map, links);
                                mtx_unlock(&bounce_lock);
                                return (EINPROGRESS);
                        }
                }
                mtx_unlock(&bounce_lock);
        }

        vaddr = (vm_offset_t)buf;
        lastaddr = *lastaddrp;
        bmask = ~(dmat->boundary - 1);

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

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

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

                if (map->pagesneeded != 0 && run_filter(dmat, curaddr))
                        curaddr = add_bounce_page(dmat, map, vaddr, sgsize);

                /*
                 * Insert chunk into a segment, coalescing with
                 * previous segment if possible.
                 */
                if (first) {
                        segs[seg].ds_addr = curaddr;
                        segs[seg].ds_len = sgsize;
                        first = 0;
                } else {
                        if (needbounce == 0 && curaddr == lastaddr &&
                            (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
                            (dmat->boundary == 0 ||
                             (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
                                segs[seg].ds_len += sgsize;
                        else {
                                if (++seg >= dmat->nsegments)
                                        break;
                                segs[seg].ds_addr = curaddr;
                                segs[seg].ds_len = sgsize;
                        }
                }

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

        *segp = seg;
        *lastaddrp = lastaddr;

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

/*
 * Map the buffer buf into bus space using the dmamap map.
 */
int
bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
                bus_size_t buflen, bus_dmamap_callback_t *callback,
                void *callback_arg, int flags)
{
        bus_addr_t              lastaddr = 0;
        int                     error, nsegs = 0;

        if (map != NULL) {
                flags |= BUS_DMA_WAITOK;
                map->callback = callback;
                map->callback_arg = callback_arg;
        }

        error = _bus_dmamap_load_buffer(dmat, map, buf, buflen, NULL, flags,
             &lastaddr, dmat->segments, &nsegs, 1);

        CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
            __func__, dmat, dmat->flags, error, nsegs + 1);

        if (error == EINPROGRESS) {
                return (error);
        }

        if (error)
                (*callback)(callback_arg, dmat->segments, 0, error);
        else
                (*callback)(callback_arg, dmat->segments, nsegs + 1, 0);

        /*
         * Return ENOMEM to the caller so that it can pass it up the stack.
         * This error only happens when NOWAIT is set, so deferal is disabled.
         */
        if (error == ENOMEM)
                return (error);

        return (0);
}

/*
 * Like _bus_dmamap_load(), but for mbufs.
 */
int
bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
                     struct mbuf *m0,
                     bus_dmamap_callback2_t *callback, void *callback_arg,
                     int flags)
{
        int nsegs, error;

        M_ASSERTPKTHDR(m0);

        flags |= BUS_DMA_NOWAIT;
        nsegs = 0;
        error = 0;
        if (m0->m_pkthdr.len <= dmat->maxsize) {
                int first = 1;
                bus_addr_t lastaddr = 0;
                struct mbuf *m;

                for (m = m0; m != NULL && error == 0; m = m->m_next) {
                        if (m->m_len > 0) {
                                error = _bus_dmamap_load_buffer(dmat, map,
                                                m->m_data, m->m_len,
                                                NULL, flags, &lastaddr,
                                                dmat->segments, &nsegs, first);
                                first = 0;
                        }
                }
        } else {
                error = EINVAL;
        }

        if (error) {
                /* force "no valid mappings" in callback */
                (*callback)(callback_arg, dmat->segments, 0, 0, error);
        } else {
                (*callback)(callback_arg, dmat->segments,
                            nsegs+1, m0->m_pkthdr.len, error);
        }
        CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
            __func__, dmat, dmat->flags, error, nsegs + 1);
        return (error);
}

int
bus_dmamap_load_mbuf_sg(bus_dma_tag_t dmat, bus_dmamap_t map,
                        struct mbuf *m0, bus_dma_segment_t *segs, int *nsegs,
                        int flags)
{
        int error;

        M_ASSERTPKTHDR(m0);

        flags |= BUS_DMA_NOWAIT;
        *nsegs = 0;
        error = 0;
        if (m0->m_pkthdr.len <= dmat->maxsize) {
                int first = 1;
                bus_addr_t lastaddr = 0;
                struct mbuf *m;

                for (m = m0; m != NULL && error == 0; m = m->m_next) {
                        if (m->m_len > 0) {
                                error = _bus_dmamap_load_buffer(dmat, map,
                                                m->m_data, m->m_len,
                                                NULL, flags, &lastaddr,
                                                segs, nsegs, first);
                                first = 0;
                        }
                }
        } else {
                error = EINVAL;
        }

        /* XXX FIXME: Having to increment nsegs is really annoying */
        ++*nsegs;
        CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
            __func__, dmat, dmat->flags, error, *nsegs);
        return (error);
}

#if 0
/*
 * Like _bus_dmamap_load(), but for uios.
 */
int
bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
                    struct uio *uio,
                    bus_dmamap_callback2_t *callback, void *callback_arg,
                    int flags)
{
        bus_addr_t lastaddr;
        int nsegs, error, first, i;
        bus_size_t resid;
        struct iovec *iov;
        pmap_t pmap;

        flags |= BUS_DMA_NOWAIT;
        resid = uio->uio_resid;
        iov = uio->uio_iov;

        if (uio->uio_segflg == UIO_USERSPACE) {
                KASSERT(uio->uio_td != NULL,
                        ("bus_dmamap_load_uio: USERSPACE but no proc"));
                pmap = vmspace_pmap(uio->uio_td->td_proc->p_vmspace);
        } else
                pmap = NULL;

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

                if (minlen > 0) {
                        error = _bus_dmamap_load_buffer(dmat, map,
                                        addr, minlen, pmap, flags, &lastaddr,
                                        dmat->segments, &nsegs, first);
                        first = 0;

                        resid -= minlen;
                }
        }

        if (error) {
                /* force "no valid mappings" in callback */
                (*callback)(callback_arg, dmat->segments, 0, 0, error);
        } else {
                (*callback)(callback_arg, dmat->segments,
                            nsegs+1, uio->uio_resid, error);
        }
        CTR5(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d nsegs %d",
            __func__, dmat, dmat->flags, error, nsegs + 1);
        return (error);
}
#endif

/*
 * Release the mapping held by map.
 */
void
_bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
{
        struct bounce_page *bpage;

        while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
                STAILQ_REMOVE_HEAD(&map->bpages, links);
                free_bounce_page(dmat, bpage);
        }
}

void
_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
{
        struct bounce_page *bpage;

        if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
                /*
                 * Handle data bouncing.  We might also
                 * want to add support for invalidating
                 * the caches on broken hardware
                 */
                dmat->bounce_zone->total_bounced++;
                CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
                    "performing bounce", __func__, op, dmat, dmat->flags);

                if (op & BUS_DMASYNC_PREWRITE) {
                        while (bpage != NULL) {
                                bcopy((void *)bpage->datavaddr,
                                      (void *)bpage->vaddr,
                                      bpage->datacount);
                                bpage = STAILQ_NEXT(bpage, links);
                        }
                }

                if (op & BUS_DMASYNC_POSTREAD) {
                        while (bpage != NULL) {
                                bcopy((void *)bpage->vaddr,
                                      (void *)bpage->datavaddr,
                                      bpage->datacount);
                                bpage = STAILQ_NEXT(bpage, links);
                        }
                }
        }
}

void
init_bounce_pages()
{

        total_bpages = 0;
        STAILQ_INIT(&bounce_zone_list);
        STAILQ_INIT(&bounce_map_waitinglist);
        STAILQ_INIT(&bounce_map_callbacklist);
        mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
}

/* Haiku extension */
void
uninit_bounce_pages()
{
        /* XXX deep free */

        mtx_destroy(&bounce_lock);
}

static struct sysctl_ctx_list *
busdma_sysctl_tree(struct bounce_zone *bz)
{
        return (&bz->sysctl_tree);
}

static struct sysctl_oid *
busdma_sysctl_tree_top(struct bounce_zone *bz)
{
        return (bz->sysctl_tree_top);
}

static int
alloc_bounce_zone(bus_dma_tag_t dmat)
{
        struct bounce_zone *bz;

        /* Check to see if we already have a suitable zone */
        STAILQ_FOREACH(bz, &bounce_zone_list, links) {
                if ((dmat->alignment <= bz->alignment)
                 && (dmat->boundary <= bz->boundary)
                 && (dmat->lowaddr >= bz->lowaddr)) {
                        dmat->bounce_zone = bz;
                        return (0);
                }
        }

        if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
            M_NOWAIT | M_ZERO)) == NULL)
                return (ENOMEM);

        STAILQ_INIT(&bz->bounce_page_list);
        bz->free_bpages = 0;
        bz->reserved_bpages = 0;
        bz->active_bpages = 0;
        bz->lowaddr = dmat->lowaddr;
        bz->alignment = dmat->alignment;
        bz->boundary = dmat->boundary;
        snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
        busdma_zonecount++;
        snprintf(bz->lowaddrid, 18, "%llx", (uintmax_t)bz->lowaddr);
        STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
        dmat->bounce_zone = bz;

        sysctl_ctx_init(&bz->sysctl_tree);
        bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
            SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
            CTLFLAG_RD, 0, "");
        if (bz->sysctl_tree_top == NULL) {
                sysctl_ctx_free(&bz->sysctl_tree);
                return (0);     /* XXX error code? */
        }

        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
            "Total bounce pages");
        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
            "Free bounce pages");
        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
            "Reserved bounce pages");
        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
            "Active bounce pages");
        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
            "Total bounce requests");
        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
            "Total bounce requests that were deferred");
        SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
        SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
            SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
            "boundary", CTLFLAG_RD, &bz->boundary, 0, "");

        return (0);
}

static int
alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
{
        struct bounce_zone *bz;
        int count;

        bz = dmat->bounce_zone;
        count = 0;
        while (numpages > 0) {
                struct bounce_page *bpage;

                bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
                                                     M_NOWAIT | M_ZERO);

                if (bpage == NULL)
                        break;
                bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
                                                         M_NOWAIT, 0ul,
                                                         bz->lowaddr,
                                                         PAGE_SIZE,
                                                         bz->boundary);
                if (bpage->vaddr == 0) {
                        free(bpage, M_DEVBUF);
                        break;
                }
                bpage->busaddr = pmap_kextract(bpage->vaddr);
                mtx_lock(&bounce_lock);
                STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
                total_bpages++;
                bz->total_bpages++;
                bz->free_bpages++;
                mtx_unlock(&bounce_lock);
                count++;
                numpages--;
        }
        return (count);
}

static int
reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
{
        struct bounce_zone *bz;
        int pages;

        mtx_assert(&bounce_lock, MA_OWNED);
        bz = dmat->bounce_zone;
        pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
        if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
                return (map->pagesneeded - (map->pagesreserved + pages));
        bz->free_bpages -= pages;
        bz->reserved_bpages += pages;
        map->pagesreserved += pages;
        pages = map->pagesneeded - map->pagesreserved;

        return (pages);
}

static bus_addr_t
add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
                bus_size_t size)
{
        struct bounce_zone *bz;
        struct bounce_page *bpage;

        KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
        KASSERT(map != NULL && map != &nobounce_dmamap,
            ("add_bounce_page: bad map %p", map));

        bz = dmat->bounce_zone;
        if (map->pagesneeded == 0)
                panic("add_bounce_page: map doesn't need any pages");
        map->pagesneeded--;

        if (map->pagesreserved == 0)
                panic("add_bounce_page: map doesn't need any pages");
        map->pagesreserved--;

        mtx_lock(&bounce_lock);
        bpage = STAILQ_FIRST(&bz->bounce_page_list);
        if (bpage == NULL)
                panic("add_bounce_page: free page list is empty");

        STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
        bz->reserved_bpages--;
        bz->active_bpages++;
        mtx_unlock(&bounce_lock);

        bpage->datavaddr = vaddr;
        bpage->datacount = size;
        STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
        return (bpage->busaddr);
}

static void
free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
{
        struct bus_dmamap *map;
        struct bounce_zone *bz;

        bz = dmat->bounce_zone;
        bpage->datavaddr = 0;
        bpage->datacount = 0;

        mtx_lock(&bounce_lock);
        STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
        bz->free_bpages++;
        bz->active_bpages--;
        if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
                if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
                        STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
                        STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
                                           map, links);
                        busdma_swi_pending = 1;
                        bz->total_deferred++;
#if 0
                        swi_sched(vm_ih, 0);
#endif
                        busdma_swi();
                }
        }
        mtx_unlock(&bounce_lock);
}

void
busdma_swi(void)
{
        bus_dma_tag_t dmat;
        struct bus_dmamap *map;

        mtx_lock(&bounce_lock);
        while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
                STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
                mtx_unlock(&bounce_lock);
                dmat = map->dmat;
                (dmat->lockfunc)(dmat->lockfuncarg, BUS_DMA_LOCK);
                bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
                                map->callback, map->callback_arg, /*flags*/0);
                (dmat->lockfunc)(dmat->lockfuncarg, BUS_DMA_UNLOCK);
                mtx_lock(&bounce_lock);
        }
        mtx_unlock(&bounce_lock);
}