/* $NetBSD: sgmap.c,v 1.21 2023/12/20 15:34:45 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>
__KERNEL_RCSID(0, "$NetBSD: sgmap.c,v 1.21 2023/12/20 15:34:45 thorpej Exp $");

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

#include <uvm/uvm_extern.h>

#include <machine/sgmap.h>

void
vax_sgmap_init(bus_dma_tag_t t, struct vax_sgmap *sgmap, const char *name,
        bus_addr_t sgvabase, bus_size_t sgvasize, struct pte *ptva,
        bus_size_t minptalign)
{
        bus_dma_segment_t seg;
        size_t ptsize;
        int rseg;

        if (sgvasize & PGOFSET) {
                printf("size botch for sgmap `%s'\n", name);
                goto die;
        }

        sgmap->aps_sgvabase = sgvabase;
        sgmap->aps_sgvasize = sgvasize;

        if (ptva != NULL) {
                /*
                 * We already have a page table; this may be a system
                 * where the page table resides in bridge-resident SRAM.
                 */
                sgmap->aps_pt = ptva;
        } else {
                /*
                 * Compute the page table size and allocate it.  At minimum,
                 * this must be aligned to the page table size.  However,
                 * some platforms have more strict alignment reqirements.
                 */
                ptsize = (sgvasize / VAX_NBPG) * sizeof(struct pte);
                if (minptalign != 0) {
                        if (minptalign < ptsize)
                                minptalign = ptsize;
                } else
                        minptalign = ptsize;
                if (bus_dmamem_alloc(t, ptsize, minptalign, 0, &seg, 1, &rseg,
                    BUS_DMA_NOWAIT)) {
                        panic("unable to allocate page table for sgmap `%s'",
                            name);
                        goto die;
                }
                sgmap->aps_pt = (struct pte *)(seg.ds_addr | KERNBASE);
        }

        /*
         * Create the arena used to manage the virtual address
         * space.
         */
        sgmap->aps_arena = vmem_create(name, sgvabase, sgvasize,
                                       VAX_NBPG,        /* quantum */
                                       NULL,            /* importfn */
                                       NULL,            /* releasefn */
                                       NULL,            /* source */
                                       0,               /* qcache_max */
                                       VM_SLEEP,
                                       IPL_VM);
        KASSERT(sgmap->aps_arena != NULL);
        return;
 die:
        panic("vax_sgmap_init");
}

int
vax_sgmap_alloc(bus_dmamap_t map, bus_size_t origlen, struct vax_sgmap *sgmap,
        int flags)
{
        int error;
        bus_size_t len = origlen;

#ifdef DIAGNOSTIC
        if (map->_dm_flags & DMAMAP_HAS_SGMAP)
                panic("vax_sgmap_alloc: already have sgva space");
#endif

        /* If we need a spill page (for the VS4000 SCSI), make sure we 
         * allocate enough space for an extra page.
         */
        if (flags & VAX_BUS_DMA_SPILLPAGE) {
                len += VAX_NBPG;
        }

        map->_dm_sgvalen = vax_round_page(len);
#define DEBUG_SGMAP 0
#if DEBUG_SGMAP
        printf("len %x -> %x, _dm_sgvalen %x _dm_boundary %x boundary %x -> ",
            //origlen, len, map->_dm_sgvalen, map->_dm_boundary, boundary);
            (unsigned int)origlen, (unsigned int)len, (unsigned int)map->_dm_sgvalen, (unsigned int)map->_dm_boundary, 1);
#endif

        const vm_flag_t vmflags = VM_BESTFIT |
            ((flags & BUS_DMA_NOWAIT) ? VM_NOSLEEP : VM_SLEEP);

        error = vmem_xalloc(sgmap->aps_arena, map->_dm_sgvalen,
                            0,                  /* alignment */
                            0,                  /* phase */
                            map->_dm_boundary,  /* nocross */
                            VMEM_ADDR_MIN,      /* minaddr */
                            VMEM_ADDR_MAX,      /* maxaddr */
                            vmflags,
                            &map->_dm_sgva);

#if DEBUG_SGMAP
        printf("error %d _dm_sgva %lx\n", error, map->_dm_sgva);
#endif

        if (error == 0)
                map->_dm_flags |= DMAMAP_HAS_SGMAP;
        else
                map->_dm_flags &= ~DMAMAP_HAS_SGMAP;
        
        return (error);
}

void
vax_sgmap_free(bus_dmamap_t map, struct vax_sgmap *sgmap)
{

#ifdef DIAGNOSTIC
        if ((map->_dm_flags & DMAMAP_HAS_SGMAP) == 0)
                panic("vax_sgmap_free: no sgva space to free");
#endif

        vmem_xfree(sgmap->aps_arena, map->_dm_sgva, map->_dm_sgvalen);

        map->_dm_flags &= ~DMAMAP_HAS_SGMAP;
}

int
vax_sgmap_reserve(bus_addr_t ba, bus_size_t len, struct vax_sgmap *sgmap)
{
        return vmem_xalloc_addr(sgmap->aps_arena, ba, len, VM_NOSLEEP);
}

int
vax_sgmap_load(bus_dma_tag_t t, bus_dmamap_t map, void *buf, bus_size_t buflen,
        struct proc *p, int flags, struct vax_sgmap *sgmap)
{
        vaddr_t endva, va = (vaddr_t)buf;
        paddr_t pa;
        bus_addr_t dmaoffset;
        bus_size_t dmalen;
        long *pte, *page_table = (long *)sgmap->aps_pt;
        int pteidx, error;

        /*
         * Make sure that on error condition we return "no valid mappings".
         */
        map->dm_mapsize = 0;
        map->dm_nsegs = 0;

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

        /*
         * Remember the offset into the first page and the total
         * transfer length.
         */
        dmaoffset = ((u_long)buf) & VAX_PGOFSET;
        dmalen = buflen;


        /*
         * Allocate the necessary virtual address space for the
         * mapping.  Round the size, since we deal with whole pages.
         */
        endva = vax_round_page(va + buflen);
        va = vax_trunc_page(va);
        if ((map->_dm_flags & DMAMAP_HAS_SGMAP) == 0) {
                error = vax_sgmap_alloc(map, (endva - va), sgmap, flags);
                if (error)
                        return (error);
        }

        pteidx = map->_dm_sgva >> VAX_PGSHIFT;
        pte = &page_table[pteidx];

        /*
         * Generate the DMA address.
         */
        map->dm_segs[0].ds_addr = map->_dm_sgva + dmaoffset;
        map->dm_segs[0].ds_len = dmalen;


        map->_dm_pteidx = pteidx;
        map->_dm_ptecnt = 0;

        /*
         * Create the bus-specific page tables.
         * Can be done much more efficient than this.
         */
        for (; va < endva; va += VAX_NBPG, pte++, map->_dm_ptecnt++) {
                /*
                 * Get the physical address for this segment.
                 */
                if (p != NULL)
                        (void) pmap_extract(p->p_vmspace->vm_map.pmap, va, &pa);
                else
                        pa = kvtophys(va);

                /*
                 * Load the current PTE with this page.
                 */
                *pte = (pa >> VAX_PGSHIFT) | PG_V;
        }
        /* The VS4000 SCSI prefetcher doesn't like to end on a page boundary
         * so add an extra page to quiet it down.
         */
        if (flags & VAX_BUS_DMA_SPILLPAGE) {
                *pte = pte[-1];
                map->_dm_ptecnt++;
        }

        map->dm_mapsize = buflen;
        map->dm_nsegs = 1;
        return (0);
}

int
vax_sgmap_load_mbuf(bus_dma_tag_t t, bus_dmamap_t map, struct mbuf *m,
        int flags, struct vax_sgmap *sgmap)
{

        panic("vax_sgmap_load_mbuf : not implemented");
}

int
vax_sgmap_load_uio(bus_dma_tag_t t, bus_dmamap_t map, struct uio *uio,
        int flags, struct vax_sgmap *sgmap)
{

        panic("vax_sgmap_load_uio : not implemented");
}

int
vax_sgmap_load_raw(bus_dma_tag_t t, bus_dmamap_t map, bus_dma_segment_t *segs,
        int nsegs, bus_size_t size, int flags, struct vax_sgmap *sgmap)
{

        panic("vax_sgmap_load_raw : not implemented");
}

void
vax_sgmap_unload(bus_dma_tag_t t, bus_dmamap_t map, struct vax_sgmap *sgmap)
{
        long *pte, *page_table = (long *)sgmap->aps_pt;
        int ptecnt;

        /*
         * Invalidate the PTEs for the mapping.
         */
        for (ptecnt = map->_dm_ptecnt, pte = &page_table[map->_dm_pteidx];
                ptecnt-- != 0; ) {
                *pte++ = 0;
        }

        /*
         * Free the virtual address space used by the mapping
         * if necessary.
         */
        if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
                vax_sgmap_free(map, sgmap);
        /*
         * Mark the mapping invalid.
         */
        map->dm_mapsize = 0;
        map->dm_nsegs = 0;
}