/*
 * Copyright (c) 2001 Wind River Systems
 * Copyright (c) 1997, 1998, 1999, 2000, 2001
 *	Bill Paul <wpaul@windriver.com>.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Bill Paul.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Bill Paul 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 Bill Paul OR THE VOICES IN HIS HEAD
 * 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.
 *
 * $FreeBSD$
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>

#include <machine/bus.h>
#include <machine/md_var.h>

#include <sys/busdma.h>


struct bus_dma_map_arg {
	int curseg;
	int maxseg;
	bus_dma_segment_t *segs;
};

static void
	bus_dmamap_list_put __P((bus_dma_tag_t, bus_dmahead_t, bus_dmalist_t));
static bus_dmalist_t
	bus_dmamap_list_get __P((bus_dma_tag_t, bus_dmahead_t));
static void
	bus_dmamap_load_mbuf_cb __P((void *, bus_dma_segment_t *, int, int));

int
bus_dmamap_list_init(dmat, listhead, cnt, flag)
	bus_dma_tag_t dmat;
	bus_dmahead_t listhead;
	int cnt, flag;
{
	bus_dmalist_t entry;
	int i, error;

	SLIST_INIT(listhead);

	for (i = 0; i < cnt; i++) {
		entry = malloc(sizeof(struct bus_dmamap_list_entry),
		    M_DEVBUF, M_NOWAIT);
		if (entry == NULL) {
			bus_dmamap_list_destroy(dmat, listhead);
			return(ENOBUFS);
		}
		entry->map = NULL;
		if ((error = bus_dmamap_create(dmat, 0, &entry->map))) {
			bus_dmamap_list_destroy(dmat, listhead);
			return(error);
		}
		SLIST_INSERT_HEAD(listhead, entry, link);
	}

	return(0);
}

void
bus_dmamap_list_destroy(dmat, listhead)
	bus_dma_tag_t dmat;
	bus_dmahead_t listhead;
{
	bus_dmalist_t entry;

	while (!SLIST_EMPTY(listhead)) {
		entry = SLIST_FIRST(listhead);
		SLIST_REMOVE_HEAD(listhead, link);
		bus_dmamap_destroy(dmat, entry->map);
		free(entry, M_DEVBUF);
	}

	return;
}

static bus_dmalist_t
bus_dmamap_list_get(dmat, listhead)
	bus_dma_tag_t dmat;
	bus_dmahead_t listhead;
{
	bus_dmalist_t entry;

	if (SLIST_EMPTY(listhead))
		return(NULL);

	entry = SLIST_FIRST(listhead);
	SLIST_REMOVE_HEAD(listhead, link);

	return(entry);
}

static void
bus_dmamap_list_put(dmat, listhead, entry)
	bus_dma_tag_t dmat;
	bus_dmahead_t listhead;
	bus_dmalist_t entry;
{
	SLIST_INSERT_HEAD(listhead, entry, link);
	return;
}

static void
bus_dmamap_load_mbuf_cb(arg, segs, nseg, error)
	void *arg;
	bus_dma_segment_t *segs;
	int nseg, error;
{
	struct bus_dma_map_arg *a;
	bus_dma_segment_t *s;
	int i;

	a = arg;

	if (error) {
		a->curseg = -1;
		return;
	}

	/*
	 * Make sure there's still room left
	 * in this segment array.
	 */
	if ((a->curseg + nseg) > a->maxseg) {
		a->curseg = -1;
		return;
	}

	s = a->segs;

	for (i = 0; i < nseg; i++) {
		s[i + a->curseg].ds_len = segs[i].ds_len;
		s[i + a->curseg].ds_addr = segs[i].ds_addr;
	}

	a->curseg += i;

	return;
}

void
bus_dmamap_unload_mbuf(dmat, m0)
	bus_dma_tag_t dmat;
	struct mbuf *m0;
{
	struct mbuf *m;
	bus_dmalist_t entry;

	for (m = m0; m != NULL; m = m->m_next) {
		if (m->m_len != 0) {
			entry = (bus_dmalist_t)m->m_nextpkt;
			bus_dmamap_unload(dmat, entry->map);
		}
	}

	return;
}

void
bus_dmamap_destroy_mbuf(dmat, listhead, m0)
	bus_dma_tag_t dmat;
	struct bus_dmamap_list_head *listhead;
	struct mbuf *m0;
{
	struct mbuf *m;
	bus_dmalist_t entry;

	for (m = m0; m != NULL; m = m->m_next) {
		if (m->m_len != 0) {
			entry = (bus_dmalist_t)m->m_nextpkt;
			m->m_nextpkt = NULL;
			bus_dmamap_list_put(dmat, listhead, entry);
		}
	}

	return;
}

void
bus_dmamap_sync_mbuf(dmat, m0, op)
	bus_dma_tag_t dmat;
	struct mbuf *m0;
	bus_dmasync_op_t op;
{
	struct mbuf *m;
	bus_dmalist_t entry;

	for (m = m0; m != NULL; m = m->m_next) {
		if (m->m_len != 0) {
			entry = (bus_dmalist_t)m->m_nextpkt;
			bus_dmamap_sync(dmat, entry->map, op);
		}
	}

	return;
}

/*
 * Use the busdma API to DMA map the buffers in an mbuf list.
 * Note that this is meant to be used at the device driver level.
 * We abuse the mbuf header a little bit in order to stash the
 * DMA map pointer without forcing device drivers to allocate
 * extra space. The m_nextpkt pointer in the mbuf header will
 * always be available for us to use in a network driver context:
 * from the RX side, we allocate the mbufs ourselves, so we know
 * the m_nextpkt pointer will be unused, and from the TX side, we
 * know we will always be passed an mbuf list, and never an mbuf
 * chain.
 *
 * Note that we deal with the case where the mbuf's data region
 * spans discontiguous pages. The caller has to make sure to pass
 * us a large enough segment array to handle all the possible
 * segment mappings that the busdma code might cough up.
 */
int
bus_dmamap_load_mbuf(dmat, listhead, m0, segs, nseg)
	bus_dma_tag_t dmat;
	struct bus_dmamap_list_head *listhead;
	struct mbuf *m0;
	bus_dma_segment_t *segs;
	int *nseg;
{
	struct mbuf *m;
	bus_dmalist_t entry;
	struct bus_dma_map_arg arg;
	int error;

	arg.curseg = 0;
	arg.maxseg = *nseg;
	arg.segs = segs;

	for (m = m0; m != NULL; m = m->m_next) {
		if (m->m_len != 0) {
			entry = bus_dmamap_list_get(dmat, listhead);
			if (entry == NULL) {
				bus_dmamap_unload_mbuf(dmat, m0);
				bus_dmamap_destroy_mbuf(dmat, listhead, m0);
				return(ENOBUFS);
			}
			m->m_nextpkt = (struct mbuf *)entry;

			if ((error = bus_dmamap_load(dmat, entry->map,
			    mtod(m, void *), m->m_len,
			    bus_dmamap_load_mbuf_cb, &arg, 0))) {
				bus_dmamap_unload_mbuf(dmat, m0);
				bus_dmamap_destroy_mbuf(dmat, listhead, m0);
				return(error);
			}

			if (arg.curseg == -1) {
				bus_dmamap_unload_mbuf(dmat, m0);
				bus_dmamap_destroy_mbuf(dmat, listhead, m0);
				return(EINVAL);
			}
		}
	}

	*nseg = arg.curseg;

	return(0);
}