/* $NetBSD: bus_dma.c,v 1.75 2026/05/11 15:23:50 thorpej 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>                  /* RCS ID & Copyright macro defns */

__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.75 2026/05/11 15:23:50 thorpej Exp $");

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

#include <uvm/uvm_extern.h>

#define _ALPHA_BUS_DMA_PRIVATE
#include <sys/bus.h>
#include <machine/intr.h>

#include <dev/bus_dma/bus_dmamem_common.h>

static int      _bus_dmamap_load_buffer_direct(bus_dma_tag_t,
                    bus_dmamap_t, void *, bus_size_t, struct vmspace *, int,
                    paddr_t *, int *, int);

extern paddr_t avail_end;       /* from pmap.c */

#define DMA_COUNT_DECL(cnt)     _DMA_COUNT_DECL(dma_direct, cnt)
#define DMA_COUNT(cnt)          _DMA_COUNT(dma_direct, cnt)

static size_t
_bus_dmamap_mapsize(int const nsegments)
{
        KASSERT(nsegments > 0);
        return sizeof(struct alpha_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 alpha_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 alpha_bus_dmamap *)mapstore;
        map->_dm_size = size;
        map->_dm_segcnt = nsegments;
        map->_dm_maxmaxsegsz = maxsegsz;
        if (t->_boundary != 0 && t->_boundary < boundary)
                map->_dm_boundary = t->_boundary;
        else
                map->_dm_boundary = boundary;
        map->_dm_flags = flags & ~(BUS_DMA_WAITOK|BUS_DMA_NOWAIT);
        map->dm_maxsegsz = maxsegsz;
        map->dm_mapsize = 0;            /* no valid mappings */
        map->dm_nsegs = 0;
        map->_dm_window = NULL;

        *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_direct(bus_dma_tag_t t, bus_dmamap_t map,
    void *buf, size_t buflen, struct vmspace *vm, int flags, paddr_t *lastaddrp,
    int *segp, int first)
{
        bus_size_t sgsize;
        bus_addr_t curaddr, lastaddr, baddr, bmask;
        vaddr_t vaddr = (vaddr_t)buf;
        int seg;
        bool address_is_valid __diagused;

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

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

                /*
                 * If we're beyond the current DMA window, indicate
                 * that and try to fall back into SGMAPs.
                 */
                if (t->_wsize != 0 && curaddr >= t->_wsize)
                        return (EINVAL);

                curaddr |= t->_wbase;

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

                /*
                 * 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;
                        first = 0;
                } else {
                        if ((map->_dm_flags & DMAMAP_NO_COALESCE) == 0 &&
                            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;
                        }
                }

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

        *segp = seg;
        *lastaddrp = lastaddr;

        /*
         * Did we fit?
         */
        if (buflen != 0) {
                /*
                 * If there is a chained window, we will automatically
                 * fall back to it.
                 */
                return (EFBIG);         /* XXX better return value here? */
        }

        return (0);
}

DMA_COUNT_DECL(load);
DMA_COUNT_DECL(load_next_window);

/*
 * Common function for loading a direct-mapped DMA map with a linear
 * buffer.  Called by bus-specific DMA map load functions with the
 * OR value appropriate for indicating "direct-mapped" for that
 * chipset.
 */
int
_bus_dmamap_load_direct(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
    bus_size_t buflen, struct proc *p, int flags)
{
        paddr_t lastaddr;
        int seg, error;
        struct vmspace *vm;

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

        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_direct(t, map, buf, buflen,
            vm, flags, &lastaddr, &seg, 1);
        if (error == 0) {
                DMA_COUNT(load);
                map->dm_mapsize = buflen;
                map->dm_nsegs = seg + 1;
                map->_dm_window = t;
        } else if (t->_next_window != NULL) {
                /*
                 * Give the next window a chance.
                 */
                DMA_COUNT(load_next_window);
                error = bus_dmamap_load(t->_next_window, map, buf, buflen,
                    p, flags);
        }
        return (error);
}

DMA_COUNT_DECL(load_mbuf);
DMA_COUNT_DECL(load_mbuf_next_window);

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

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

#ifdef DIAGNOSTIC
        if ((m0->m_flags & M_PKTHDR) == 0)
                panic("_bus_dmamap_load_mbuf_direct: 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;
                /* XXX Could be better about coalescing. */
                /* XXX Doesn't check boundaries. */
                switch (m->m_flags & (M_EXT|M_EXT_CLUSTER)) {
                case M_EXT|M_EXT_CLUSTER:
                        /* XXX KDASSERT */
                        KASSERT(m->m_ext.ext_paddr != M_PADDR_INVALID);
                        lastaddr = m->m_ext.ext_paddr +
                            (m->m_data - m->m_ext.ext_buf);
 have_addr:
                        if (first == 0 &&
                            ++seg >= map->_dm_segcnt) {
                                error = EFBIG;
                                break;
                        }

                        /*
                         * If we're beyond the current DMA window, indicate
                         * that and try to fall back into SGMAPs.
                         */
                        if (t->_wsize != 0 && lastaddr >= t->_wsize) {
                                error = EINVAL;
                                break;
                        }
                        lastaddr |= t->_wbase;

                        map->dm_segs[seg].ds_addr = lastaddr;
                        map->dm_segs[seg].ds_len = m->m_len;
                        lastaddr += m->m_len;
                        break;

                case 0:
                        lastaddr = m->m_paddr + M_BUFOFFSET(m) +
                            (m->m_data - M_BUFADDR(m));
                        goto have_addr;

                default:
                        error = _bus_dmamap_load_buffer_direct(t, map,
                            m->m_data, m->m_len, vmspace_kernel(), flags,
                            &lastaddr, &seg, first);
                }
                first = 0;
        }
        if (error == 0) {
                DMA_COUNT(load_mbuf);
                map->dm_mapsize = m0->m_pkthdr.len;
                map->dm_nsegs = seg + 1;
                map->_dm_window = t;
        } else if (t->_next_window != NULL) {
                /*
                 * Give the next window a chance.
                 */
                DMA_COUNT(load_mbuf_next_window);
                error = bus_dmamap_load_mbuf(t->_next_window, map, m0, flags);
        }
        return (error);
}

DMA_COUNT_DECL(load_uio);
DMA_COUNT_DECL(load_uio_next_window);

/*
 * Like _bus_dmamap_load_direct(), but for uios.
 */
int
_bus_dmamap_load_uio_direct(bus_dma_tag_t t, bus_dmamap_t map,
    struct uio *uio, int flags)
{
        paddr_t lastaddr;
        int seg, i, error, first;
        bus_size_t minlen, resid;
        struct vmspace *vm;
        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);
        KASSERT((map->_dm_flags & (BUS_DMA_READ|BUS_DMA_WRITE)) == 0);

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

        vm = uio->uio_vmspace;

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

                error = _bus_dmamap_load_buffer_direct(t, map,
                    addr, minlen, vm, flags, &lastaddr, &seg, first);
                first = 0;

                resid -= minlen;
        }
        if (error == 0) {
                DMA_COUNT(load_uio);
                map->dm_mapsize = uio->uio_resid;
                map->dm_nsegs = seg + 1;
                map->_dm_window = t;
        } else if (t->_next_window != NULL) {
                /*
                 * Give the next window a chance.
                 */
                DMA_COUNT(load_uio_next_window);
                error = bus_dmamap_load_uio(t->_next_window, map, uio, flags);
        }
        return (error);
}

/*
 * Like _bus_dmamap_load_direct(), but for raw memory.
 */
int
_bus_dmamap_load_raw_direct(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_direct: not implemented");
}

/*
 * Common function for unloading a DMA map.  May be called by
 * chipset-specific DMA map unload functions.
 */
void
_bus_dmamap_unload_common(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_window = NULL;
        map->_dm_flags &= ~(BUS_DMA_READ|BUS_DMA_WRITE);
}

DMA_COUNT_DECL(unload);

void
_bus_dmamap_unload(bus_dma_tag_t t, bus_dmamap_t map)
{
        KASSERT(map->_dm_window == t);
        DMA_COUNT(unload);
        _bus_dmamap_unload_common(t, map);
}

/*
 * Common function for DMA map synchronization.  May be called
 * by chipset-specific DMA map synchronization functions.
 */
void
_bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
    bus_size_t len, int ops)
{

        alpha_mb();
}

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

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

/*
 * 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)
{

        return (_bus_dmamem_alloc_range_common(t, size, alignment, boundary,
                                               segs, nsegs, rsegs, flags,
                                               low, 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 K0SEG, to avoid
         * TLB thrashing.
         */
        if (nsegs == 1) {
                *kvap = (void *)ALPHA_PHYS_TO_K0SEG(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 K0SEG.
         */
        if (kva >= (void *)ALPHA_K0SEG_BASE &&
            kva <= (void *)ALPHA_K0SEG_END)
                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 (alpha_btop((char *)rv));
}