/*      $NetBSD: bus_dma.c,v 1.65 2026/05/19 21:41:21 andvar Exp $      */

/*-
 * Copyright (c) 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.65 2026/05/19 21:41:21 andvar Exp $");

#include "opt_cputype.h"

#define _PMAX_BUS_DMA_PRIVATE

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

#include <uvm/uvm_extern.h>

#include <dev/bus_dma/bus_dmamem_common.h>

#include <mips/cache.h>

static int      _bus_dmamap_load_buffer(bus_dmamap_t,
                    void *, bus_size_t, struct vmspace *, int, vaddr_t *,
                    int *, int);

paddr_t kvtophys(vaddr_t);      /* XXX */

/*
 * The default DMA tag for all busses on the DECstation.
 */
struct pmax_bus_dma_tag pmax_default_bus_dma_tag = {
        _bus_dmamap_create,
        _bus_dmamap_destroy,
        _bus_dmamap_load,
        _bus_dmamap_load_mbuf,
        _bus_dmamap_load_uio,
        _bus_dmamap_load_raw,
        _bus_dmamap_unload,
        NULL,
        _bus_dmamem_alloc,
        _bus_dmamem_free,
        _bus_dmamem_map,
        _bus_dmamem_unmap,
        _bus_dmamem_mmap,
};

void
pmax_bus_dma_init(void)
{
#ifdef MIPS1
        if (CPUISMIPS3 == 0)
                pmax_default_bus_dma_tag._dmamap_sync = _bus_dmamap_sync_r3k;
#endif
#ifdef MIPS3
        if (CPUISMIPS3)
                pmax_default_bus_dma_tag._dmamap_sync = _bus_dmamap_sync_r4k;
#endif
}

static size_t
_bus_dmamap_mapsize(int const nsegments)
{
        KASSERT(nsegments > 0);
        return sizeof(struct pmax_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 pmax_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) ? KM_NOSLEEP : KM_SLEEP)) == NULL)
                return (ENOMEM);

        map = (struct pmax_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_vmspace = NULL;
        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));
}

/*
 * 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_dmamap_t map, void *buf, bus_size_t buflen,
    struct vmspace *vm, int flags, vaddr_t *lastaddrp, int *segp, int first)
{
        bus_size_t sgsize;
        paddr_t pa;
        bus_addr_t curaddr, lastaddr, baddr, bmask;
        vaddr_t vaddr = (vaddr_t)buf;
        int seg;

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

        for (seg = *segp; buflen > 0 ; ) {
                /*
                 * Get the physical address for this segment.
                 */
                if (!VMSPACE_IS_KERNEL_P(vm))
                        (void) pmap_extract(vm_map_pmap(&vm->vm_map),
                            vaddr, &pa);
                else
                        pa = kvtophys(vaddr);
                curaddr = pa;

                /*
                 * Compute the segment size, and adjust counts.
                 */
                sgsize = PAGE_SIZE - (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
                 * the previous segment if possible.
                 */
                if (first) {
                        map->dm_segs[seg].ds_addr = curaddr;
                        map->dm_segs[seg].ds_len = sgsize;
                        map->dm_segs[seg]._ds_vaddr = vaddr;
                        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;
                                map->dm_segs[seg].ds_len = sgsize;
                                map->dm_segs[seg]._ds_vaddr = vaddr;
                        }
                }

                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;
}

/*
 * Common function for loading a direct-mapped DMA map with a linear
 * buffer.
 */
int
_bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
    bus_size_t buflen, struct proc *p, int flags)
{
        vaddr_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(map, buf, buflen,
            vm, flags, &lastaddr, &seg, 1);
        if (error == 0) {
                map->dm_mapsize = buflen;
                map->dm_nsegs = seg + 1;
                map->_dm_vmspace = vm;

                /*
                 * For linear buffers, we support marking the mapping
                 * as COHERENT.
                 *
                 * XXX Check TLB entries for cache-inhibit bits?
                 */
                if (buf >= (void *)MIPS_KSEG1_START &&
                    buf < (void *)MIPS_KSEG2_START)
                        map->_dm_flags |= PMAX_DMAMAP_COHERENT;
        }
        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)
{
        vaddr_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("_bus_dmamap_load_mbuf: no packet header");
#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(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;
                map->_dm_vmspace = vmspace_kernel();    /* always kernel */
        }
        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)
{
        vaddr_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 = iov[i].iov_base;

                error = _bus_dmamap_load_buffer(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;
                map->_dm_vmspace = uio->uio_vmspace;
        }
        return error;
}

/*
 * Like _bus_dmamap_load(), but for raw memory.
 */
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
 * chipset-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;
        map->_dm_flags &= ~PMAX_DMAMAP_COHERENT;
        map->_dm_vmspace = NULL;
}

#ifdef MIPS1
/*
 * Common function for DMA map synchronization.  May be called
 * by chipset-specific DMA map synchronization functions.
 *
 * This is the R3000 version.
 */
void
_bus_dmamap_sync_r3k(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{
        bus_size_t minlen;
        bus_addr_t addr;
        int i;

        /*
         * Mixing 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_r3k: mix PRE and POST");

#ifdef DIAGNOSTIC
        if (offset >= map->dm_mapsize)
                panic("_bus_dmamap_sync_r3k: bad offset %lu (map size is %lu)",
                      offset, map->dm_mapsize);
        if (len == 0 || (offset + len) > map->dm_mapsize)
                panic("_bus_dmamap_sync_r3k: bad length");
#endif

        /*
         * The R3000 cache is write-through.  Therefore, we only need
         * to drain the write buffer on PREWRITE.  The cache is not
         * coherent, however, so we need to invalidate the data cache
         * on PREREAD (should we do it POSTREAD instead?).
         *
         * POSTWRITE (and POSTREAD, currently) are noops.
         */

        if (ops & BUS_DMASYNC_PREWRITE) {
                /*
                 * Flush the write buffer.
                 */
                wbflush();
        }

        /*
         * If we're not doing PREREAD, nothing more to do.
         */
        if ((ops & BUS_DMASYNC_PREREAD) == 0)
                return;

        /*
         * No cache invalidation is necessary if the DMA map covers
         * COHERENT DMA-safe memory (which is mapped un-cached).
         */
        if (map->_dm_flags & PMAX_DMAMAP_COHERENT)
                return;

        /*
         * If we are going to hit something as large or larger
         * than the entire data cache, just nail the whole thing.
         *
         * NOTE: Even though this is `wbinv_all', since the cache is
         * write-through, it just invalidates it.
         */
        if (len >= mips_cache_info.mci_pdcache_size) {
                mips_dcache_wbinv_all();
                return;
        }

        for (i = 0; i < map->dm_nsegs && len != 0; i++) {
                /* Find the beginning segment. */
                if (offset >= map->dm_segs[i].ds_len) {
                        offset -= map->dm_segs[i].ds_len;
                        continue;
                }

                /*
                 * Now at the first segment to sync; nail
                 * each segment until we have exhausted the
                 * length.
                 */
                minlen = len < map->dm_segs[i].ds_len - offset ?
                    len : map->dm_segs[i].ds_len - offset;

                addr = map->dm_segs[i].ds_addr;

#ifdef BUS_DMA_DEBUG
                printf("%s: flushing segment %d (%#jx..%#jx) ...", __func__,
                    i, (intmax_t)addr + offset,
                    (intmax_t)addr + offset + minlen - 1);
#endif
                mips_dcache_inv_range(
                    MIPS_PHYS_TO_KSEG0(addr + offset), minlen);
#ifdef BUS_DMA_DEBUG
                printf("\n");
#endif
                offset = 0;
                len -= minlen;
        }
}
#endif /* MIPS1 */

#ifdef MIPS3
/*
 * Common function for DMA map synchronization.  May be called
 * by chipset-specific DMA map synchronization functions.
 *
 * This is the R4000 version.
 */
void
_bus_dmamap_sync_r4k(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{
        bus_size_t minlen;
        bus_addr_t addr;
        int i, useindex;

        /*
         * Mixing 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_r4k: mix PRE and POST");

#ifdef DIAGNOSTIC
        if (offset >= map->dm_mapsize)
                panic("_bus_dmamap_sync_r4k: bad offset %lu (map size is %lu)",
                      offset, map->dm_mapsize);
        if (len == 0 || (offset + len) > map->dm_mapsize)
                panic("_bus_dmamap_sync_r4k: bad length");
#endif

        /*
         * The R4000 cache is virtually-indexed, write-back.  This means
         * we need to do the following things:
         *
         *      PREREAD -- Invalidate D-cache.  Note we might have
         *      to also write-back here if we have to use an Index
         *      op, or if the buffer start/end is not cache-line aligned.
         *
         *      PREWRITE -- Write-back the D-cache.  If we have to use
         *      an Index op, we also have to invalidate.  Note that if
         *      we are doing PREREAD|PREWRITE, we can collapse everything
         *      into a single op.
         *
         *      POSTREAD -- Nothing.
         *
         *      POSTWRITE -- Nothing.
         */

        /*
         * Flush the write buffer.
         * XXX Is this always necessary?
         */
        wbflush();

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

        /*
         * If the mapping is of COHERENT DMA-safe memory, no cache
         * flush is necessary.
         */
        if (map->_dm_flags & PMAX_DMAMAP_COHERENT)
                return;

        /*
         * If the mapping belongs to the kernel, or if it belongs
         * to the currently-running process (XXX actually, vmspace),
         * then we can use Hit ops.  Otherwise, Index ops.
         *
         * This should be true the vast majority of the time.
         */
        if (__predict_true(VMSPACE_IS_KERNEL_P(map->_dm_vmspace) ||
            map->_dm_vmspace == curproc->p_vmspace))
                useindex = 0;
        else
                useindex = 1;

        for (i = 0; i < map->dm_nsegs && len != 0; i++) {
                /* Find the beginning segment. */
                if (offset >= map->dm_segs[i].ds_len) {
                        offset -= map->dm_segs[i].ds_len;
                        continue;
                }

                /*
                 * Now at the first segment to sync; nail
                 * each segment until we have exhausted the
                 * length.
                 */
                minlen = len < map->dm_segs[i].ds_len - offset ?
                    len : map->dm_segs[i].ds_len - offset;

                addr = map->dm_segs[i]._ds_vaddr;

#ifdef BUS_DMA_DEBUG
                printf("%s: flushing segment %d (%#jx..%#jx) ...", __func__,
                    i, (intmax_t)addr + offset,
                    (intmax_t)addr + offset + minlen - 1);
#endif

                /*
                 * If we are forced to use Index ops, it's always a
                 * Write-back,Invalidate, so just do one test.
                 */
                if (__predict_false(useindex)) {
                        mips_dcache_wbinv_range_index(addr + offset, minlen);
#ifdef BUS_DMA_DEBUG
                        printf("\n");
#endif
                        offset = 0;
                        len -= minlen;
                        continue;
                }

                switch (ops) {
                case BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE:
                        mips_dcache_wbinv_range(addr + offset, minlen);
                        break;

                case BUS_DMASYNC_PREREAD:
#if 1
                        mips_dcache_wbinv_range(addr + offset, minlen);
#else
                        mips_dcache_inv_range(addr + offset, minlen);
#endif
                        break;

                case BUS_DMASYNC_PREWRITE:
                        mips_dcache_wb_range(addr + offset, minlen);
                        break;
                }
#ifdef BUS_DMA_DEBUG
                printf("\n");
#endif
                offset = 0;
                len -= minlen;
        }
}
#endif /* MIPS3 */

/*
 * 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_common(t, size, alignment, boundary,
            segs, nsegs, rsegs, flags,
            pmap_limits.avail_start /*low*/,
            pmap_limits.avail_end - 1 /*high*/));
}

/*
 * 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)
{

        _bus_dmamem_free_common(t, segs, nsegs);
}

/*
 * 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)
{

        /*
         * If we're only mapping 1 segment, use KSEG0 or KSEG1, to avoid
         * TLB thrashing.
         */
        if (nsegs == 1) {
                if (flags & BUS_DMA_COHERENT)
                        *kvap = (void *)MIPS_PHYS_TO_KSEG1(segs[0].ds_addr);
                else
                        *kvap = (void *)MIPS_PHYS_TO_KSEG0(segs[0].ds_addr);
                return 0;
        }

        return (_bus_dmamem_map_common(t, segs, nsegs, size, kvap, flags, 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)
{

        /*
         * Nothing to do if we mapped it with KSEG0 or KSEG1 (i.e.
         * not in KSEG2).
         */
        if (kva >= (void *)MIPS_KSEG0_START &&
            kva < (void *)MIPS_KSEG2_START)
                return;

        _bus_dmamem_unmap_common(t, kva, size);
}

/*
 * 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)
{
        bus_addr_t rv;

        rv = _bus_dmamem_mmap_common(t, segs, nsegs, off, prot, flags);
        if (rv == (bus_addr_t)-1)
                return (-1);

        return (mips_btop((char *)rv));
}