/*      $NetBSD: rumpdev_bus_dma.c,v 1.11 2022/02/13 19:20:41 riastradh Exp $   */

/*-
 * Copyright (c) 2013 Antti Kantee
 * 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.
 * 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 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 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.
 */

/*-
 * 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.
 */

/*
 * bus_dma(9) implementation which runs on top of rump kernel hypercalls.
 * It's essentially the same as the PowerPC implementation its based on,
 * except with some indirection and PowerPC MD features removed.
 * This should/could be expected to run on x86, other archs may need
 * some cache flushing hooks.
 *
 * From sys/arch/powerpc/powerpc/bus_dma.c:
 *      NetBSD: bus_dma.c,v 1.46 2012/02/01 09:54:03 matt Exp
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rumpdev_bus_dma.c,v 1.11 2022/02/13 19:20:41 riastradh 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 <sys/bus.h>
#include <sys/intr.h>

#include "pci_user.h"

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

/*
 * 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)
{
        bus_dmamap_t map;
        void *mapstore;
        size_t mapsize;

        /*
         * 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(*map) + sizeof(bus_dma_segment_t [nsegments - 1]);
        if ((mapstore = kmem_intr_alloc(mapsize,
            (flags & BUS_DMA_NOWAIT) ? KM_NOSLEEP : KM_SLEEP)) == NULL)
                return (ENOMEM);

        memset(mapstore, 0, mapsize);
        map = (void *)mapstore;
        map->_dm_size = size;
        map->_dm_segcnt = nsegments;
        map->_dm_maxmaxsegsz = maxsegsz;
        map->_dm_boundary = boundary;
        map->_dm_bounce_thresh = 0;
        map->_dm_flags = flags & ~(BUS_DMA_WAITOK|BUS_DMA_NOWAIT);
        map->dm_maxsegsz = maxsegsz;
        map->dm_mapsize = 0;            /* no valid mappings */
        map->dm_nsegs = 0;

        *dmamp = map;
        return (0);
}

/*
 * Common function for DMA map destruction.  May be called by bus-specific
 * DMA map destruction functions.
 */
void
bus_dmamap_destroy(bus_dma_tag_t t, bus_dmamap_t map)
{

        size_t mapsize = sizeof(*map)
            + sizeof(bus_dma_segment_t [map->_dm_segcnt - 1]);
        kmem_intr_free(map, mapsize);
}

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

//      printf("%s(%p,%p,%p,%u,%p,%#x,%p,%p,%u)\n", __func__,
//          t, map, buf, buflen, vm, flags, lastaddrp, segp, first);

        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, (void *)&curaddr);
                else
                        curaddr = vtophys(vaddr);

                /*
                 * If we're beyond the bounce threshold, notify
                 * the caller.
                 */
                if (map->_dm_bounce_thresh != 0 &&
                    curaddr >= map->_dm_bounce_thresh)
                        return (EINVAL);

                /*
                 * Compute the segment size, and adjust counts.
                 */
                sgsize = PAGE_SIZE - ((u_long)vaddr & PGOFSET);
                if (buflen < sgsize)
                        sgsize = buflen;
                sgsize = MIN(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
                            = rumpcomp_pci_virt_to_mach((void *)curaddr);
                        map->dm_segs[seg].ds_len = sgsize;
                        first = 0;
                } else {
                        if (curaddr == lastaddr &&
                            (map->dm_segs[seg].ds_len + sgsize) <=
                             map->dm_maxsegsz &&
                            (map->_dm_boundary == 0 ||
                             (map->dm_segs[seg].ds_addr & bmask) ==
                             (rumpcomp_pci_virt_to_mach((void*)curaddr)&bmask)))
                                map->dm_segs[seg].ds_len += sgsize;
                        else {
                                if (++seg >= map->_dm_segcnt)
                                        break;
                                map->dm_segs[seg].ds_addr =
                                    rumpcomp_pci_virt_to_mach((void *)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)
                return (EFBIG);         /* XXX better return value here? */

        return (0);
}

/*
 * Common function for loading a DMA map with a linear buffer.  May
 * be called by bus-specific DMA map load functions.
 */
int
bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map,
        void *buf, bus_size_t buflen, struct proc *p, int flags)
{
        paddr_t lastaddr = 0;
        int seg, error;
        struct vmspace *vm;

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

        if (buflen > map->_dm_size)
                return (EINVAL);

        if (p != NULL) {
                vm = p->p_vmspace;
        } else {
                vm = vmspace_kernel();
        }

        seg = 0;
        error = _bus_dmamap_load_buffer(t, map, buf, buflen, vm, flags,
                &lastaddr, &seg, 1);
        if (error == 0) {
                map->dm_mapsize = buflen;
                map->dm_nsegs = seg + 1;
        }
        return (error);
}

/*
 * Like _bus_dmamap_load(), but for mbufs.
 */
int
bus_dmamap_load_mbuf(bus_dma_tag_t t, bus_dmamap_t map,
        struct mbuf *m0, int flags)
{
        paddr_t lastaddr = 0;
        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, first = 0) {
                if (m->m_len == 0)
                        continue;
#ifdef POOL_VTOPHYS
                /* 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;
                                continue;
                        }
                        map->dm_segs[seg].ds_addr =
                            rumpcomp_pci_virt_to_mach((void *)lastaddr);
                        map->dm_segs[seg].ds_len = m->m_len;
                        lastaddr += m->m_len;
                        continue;

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

                default:
                        break;
                }
#endif
                error = _bus_dmamap_load_buffer(t, map, m->m_data,
                    m->m_len, vmspace_kernel(), flags, &lastaddr, &seg, first);
        }
        if (error == 0) {
                map->dm_mapsize = m0->m_pkthdr.len;
                map->dm_nsegs = seg + 1;
        }
        return (error);
}

/*
 * Like _bus_dmamap_load(), but for uios.
 */
int
bus_dmamap_load_uio(bus_dma_tag_t t, bus_dmamap_t map,
        struct uio *uio, int flags)
{
        paddr_t lastaddr = 0;
        int seg, i, error, first;
        bus_size_t minlen, resid;
        struct iovec *iov;
        void *addr;

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

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

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

                error = _bus_dmamap_load_buffer(t, map, addr, minlen,
                    uio->uio_vmspace, flags, &lastaddr, &seg, first);
                first = 0;

                resid -= minlen;
        }
        if (error == 0) {
                map->dm_mapsize = uio->uio_resid;
                map->dm_nsegs = seg + 1;
        }
        return (error);
}

/*
 * Like _bus_dmamap_load(), but for raw memory allocated with
 * bus_dmamem_alloc().
 */
int
bus_dmamap_load_raw(bus_dma_tag_t t, bus_dmamap_t map,
        bus_dma_segment_t *segs, int nsegs, bus_size_t size, int flags)
{

        panic("_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;
}

void
bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map,
        bus_addr_t offset, bus_size_t len, int ops)
{

        /* XXX: this might need some MD tweaks */
        membar_sync();
}

/*
 * 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)
{
#ifdef RUMPCOMP_USERFEATURE_PCI_DMAFREE
        vaddr_t vacookie = segs[0]._ds_vacookie;
        bus_size_t sizecookie = segs[0]._ds_sizecookie;

        rumpcomp_pci_dmafree(vacookie, sizecookie);
#else
        panic("bus_dmamem_free not implemented");
#endif
}

/*
 * Don't have hypercall for mapping scatter-gather memory.
 * So just simply fail if there's more than one segment to map
 */
int
bus_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
        size_t size, void **kvap, int flags)
{
        struct rumpcomp_pci_dmaseg *dss;
        size_t allocsize = nsegs * sizeof(*dss);
        int rv, i;

        /*
         * Though rumpcomp_pci_dmaseg "accidentally" matches the
         * bus_dma segment descriptor (at least for now), act
         * proper and actually translate it.
         */
        dss = kmem_alloc(allocsize, KM_SLEEP);
        for (i = 0; i < nsegs; i++) {
                dss[i].ds_pa = segs[i].ds_addr;
                dss[i].ds_len = segs[i].ds_len;
                dss[i].ds_vacookie = segs[i]._ds_vacookie;
        }
        rv = rumpcomp_pci_dmamem_map(dss, nsegs, size, kvap);
        kmem_free(dss, allocsize);

        return rv;
}

/*
 * 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 as long as bus_dmamem_map() is what it is */
}

paddr_t
bus_dmamem_mmap(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
        off_t off, int prot, int flags)
{

        panic("bus_dmamem_mmap not supported");
}

/*
 * Allocate physical memory from the given physical address range.
 * Called by DMA-safe memory allocation methods.
 */
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)
{
        paddr_t curaddr, lastaddr, pa;
        vaddr_t vacookie;
        size_t sizecookie;
        int curseg, error;

        /* Always round the size. */
        size = round_page(size);

        sizecookie = size;

        /*
         * Allocate pages from the VM system.
         */
#if 0
        error = uvm_pglistalloc(size, low, high, alignment, boundary,
            &mlist, nsegs, (flags & BUS_DMA_NOWAIT) == 0);
#else
        /* XXX: ignores boundary, nsegs, etc. */
        //printf("dma allocation %lx %lx %d\n", alignment, boundary, nsegs);
        error = rumpcomp_pci_dmalloc(size, alignment, &pa, &vacookie);
#endif
        if (error)
                return (error);

        /*
         * Compute the location, size, and number of segments actually
         * returned by the VM code.
         */
        curseg = 0;
        lastaddr = segs[curseg].ds_addr = pa;
        segs[curseg].ds_len = PAGE_SIZE;
        segs[curseg]._ds_vacookie = vacookie;
        segs[curseg]._ds_sizecookie = sizecookie;
        size -= PAGE_SIZE;
        pa += PAGE_SIZE;
        vacookie += PAGE_SIZE;

        for (; size;
            pa += PAGE_SIZE, vacookie += PAGE_SIZE, size -= PAGE_SIZE) {
                curaddr = pa;
                if (curaddr == (lastaddr + PAGE_SIZE) &&
                    (lastaddr & boundary) == (curaddr & boundary)) {
                        segs[curseg].ds_len += PAGE_SIZE;
                } else {
                        curseg++;
                        if (curseg >= nsegs)
                                return EFBIG;
                        segs[curseg].ds_addr = curaddr;
                        segs[curseg].ds_len = PAGE_SIZE;
                        segs[curseg]._ds_vacookie = vacookie;
                        segs[curseg]._ds_sizecookie = sizecookie;
                }
                lastaddr = curaddr;
        }
        *rsegs = curseg + 1;

        return (0);
}