NetBSD/sys/arch/alpha/common/sgmap_common.c

/* $NetBSD: sgmap_common.c,v 1.6 1998/01/18 00:05:33 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 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: sgmap_common.c,v 1.6 1998/01/18 00:05:33 thorpej Exp $");

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

#include <vm/vm.h>

#include <machine/bus.h>

#include <alpha/common/sgmapvar.h>

/*
 * Some systems will prefetch the next page during a memory -> device DMA.
 * This can cause machine checks if there is not a spill page after the
 * last page of the DMA (thus avoiding hitting an invalid SGMAP PTE).
 */
vm_offset_t	alpha_sgmap_prefetch_spill_page_va;
bus_addr_t	alpha_sgmap_prefetch_spill_page_pa;

void
alpha_sgmap_init(t, sgmap, name, wbase, sgvabase, sgvasize, ptesize, ptva,
    minptalign)
	bus_dma_tag_t t;
	struct alpha_sgmap *sgmap;
	const char *name;
	bus_addr_t wbase;
	bus_addr_t sgvabase;
	bus_size_t sgvasize;
	size_t ptesize;
	void *ptva;
	bus_size_t minptalign;
{
	bus_dma_segment_t seg;
	size_t ptsize;
	int rseg;

	if (sgvasize & PGOFSET)
		panic("alpha_sgmap_init: size botch");

	sgmap->aps_wbase = wbase;
	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;
		sgmap->aps_ptpa = 0;
	} 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 / NBPG) * ptesize;
		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("alpha_sgmap_init: can't allocate page table");
		sgmap->aps_ptpa = seg.ds_addr;
		sgmap->aps_pt = (caddr_t)ALPHA_PHYS_TO_K0SEG(sgmap->aps_ptpa);
	}

	/*
	 * Create the extent map used to manage the virtual address
	 * space.
	 */
	sgmap->aps_ex = extent_create((char *)name, sgvabase, sgvasize - 1,
	    M_DEVBUF, NULL, 0, EX_NOWAIT|EX_NOCOALESCE);
	if (sgmap->aps_ex == NULL)
		panic("alpha_sgmap_init: can't create extent map");

	/*
	 * Allocate a spill page if that hasn't already been done.
	 */
	if (alpha_sgmap_prefetch_spill_page_va == 0) {
		if (bus_dmamem_alloc(t, NBPG, 0, 0, &seg, 1, &rseg,
		    BUS_DMA_NOWAIT))
			panic("alpha_sgmap_init: can't allocate spill page");
		alpha_sgmap_prefetch_spill_page_pa = seg.ds_addr;
		alpha_sgmap_prefetch_spill_page_va =
		    ALPHA_PHYS_TO_K0SEG(alpha_sgmap_prefetch_spill_page_pa);
		bzero((caddr_t)alpha_sgmap_prefetch_spill_page_va, NBPG);
	}
}

int
alpha_sgmap_alloc(map, len, sgmap, flags)
	bus_dmamap_t map;
	bus_size_t len;
	struct alpha_sgmap *sgmap;
	int flags;
{
	int error;

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

	map->_dm_sgvalen = round_page(len);
	error = extent_alloc(sgmap->aps_ex, map->_dm_sgvalen, NBPG,
	    map->_dm_boundary, (flags & BUS_DMA_NOWAIT) ? EX_NOWAIT :
	    EX_WAITOK, &map->_dm_sgva);

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

void
alpha_sgmap_free(map, sgmap)
	bus_dmamap_t map;
	struct alpha_sgmap *sgmap;
{

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

	if (extent_free(sgmap->aps_ex, map->_dm_sgva, map->_dm_sgvalen,
	    EX_NOWAIT))
		panic("alpha_sgmap_free");

	map->_dm_flags &= ~DMAMAP_HAS_SGMAP;
}