Beispiel #1
0
/*
 * Load an ISA DMA map with a linear buffer.
 */
int
_isa_bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map,
			void *buf, bus_size_t buflen,
			struct proc *p, int flags)
{
	struct i386_isa_dma_cookie *cookie = map->_dm_cookie;
	int error;

	STAT_INCR(isa_dma_stats_loads);

	/*
	 * Check to see if we might need to bounce the transfer.
	 */
	if (cookie->id_flags & ID_MIGHT_NEED_BOUNCE) {
		/*
		 * Check if all pages are below the bounce
		 * threshold.  If they are, don't bother bouncing.
		 */
		if (_isa_dma_check_buffer(buf, buflen,
		    map->_dm_segcnt, map->_dm_boundary, p) == 0)
			return (_bus_dmamap_load(t, map, buf, buflen,
			    p, flags));

		STAT_INCR(isa_dma_stats_bounces);

		/*
		 * Allocate bounce pages, if necessary.
		 */
		if ((cookie->id_flags & ID_HAS_BOUNCE) == 0) {
			error = _isa_dma_alloc_bouncebuf(t, map, buflen,
			    flags);
			if (error)
				return (error);
		}

		/*
		 * Cache a pointer to the caller's buffer and
		 * load the DMA map with the bounce buffer.
		 */
		cookie->id_origbuf = buf;
		cookie->id_origbuflen = buflen;
		error = _bus_dmamap_load(t, map, cookie->id_bouncebuf,
		    buflen, p, flags);

		if (error) {
			/*
			 * Free the bounce pages, unless our resources
			 * are reserved for our exclusive use.
			 */
			if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
				_isa_dma_free_bouncebuf(t, map);
		}

		/* ...so _isa_bus_dmamap_sync() knows we're bouncing */
		cookie->id_flags |= ID_IS_BOUNCING;
	} else {
		/*
		 * Just use the generic load function.
		 */
		error = _bus_dmamap_load(t, map, buf, buflen, p, flags);
	}

	return (error);
}
Beispiel #2
0
/*
 * Like _isa_bus_dmamap_load(), but for mbufs.
 */
int
_isa_bus_dmamap_load_mbuf(bus_dma_tag_t t, bus_dmamap_t map, struct mbuf *m0,
	int flags)
{
	struct powerpc_isa_dma_cookie *cookie = map->_dm_cookie;
	int error;

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

#ifdef DIAGNOSTIC
	if ((m0->m_flags & M_PKTHDR) == 0)
		panic("_isa_bus_dmamap_load_mbuf: no packet header");
#endif

	if (m0->m_pkthdr.len > map->_dm_size)
		return (EINVAL);

	/*
	 * Try to load the map the normal way.  If this errors out,
	 * and we can bounce, we will.
	 */
	error = _bus_dmamap_load_mbuf(t, map, m0, flags);
	if (error == 0 ||
	    (error != 0 && (cookie->id_flags & ID_MIGHT_NEED_BOUNCE) == 0))
		return (error);

	/*
	 * First attempt failed; bounce it.
	 */

	STAT_INCR(isa_dma_stats_bounces);

	/*
	 * Allocate bounce pages, if necessary.
	 */
	if ((cookie->id_flags & ID_HAS_BOUNCE) == 0) {
		error = _isa_dma_alloc_bouncebuf(t, map, m0->m_pkthdr.len,
		    flags);
		if (error)
			return (error);
	}

	/*
	 * Cache a pointer to the caller's buffer and load the DMA map
	 * with the bounce buffer.
	 */
	cookie->id_origbuf = m0;
	cookie->id_origbuflen = m0->m_pkthdr.len;	/* not really used */
	cookie->id_buftype = ID_BUFTYPE_MBUF;
	error = _bus_dmamap_load(t, map, cookie->id_bouncebuf,
	    m0->m_pkthdr.len, NULL, flags);
	if (error) {
		/*
		 * Free the bounce pages, unless our resources
		 * are reserved for our exclusive use.
		 */
		if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
			_isa_dma_free_bouncebuf(t, map);
		return (error);
	}

	/* ...so _isa_bus_dmamap_sync() knows we're bouncing */
	cookie->id_flags |= ID_IS_BOUNCING;
	return (0);
}
Beispiel #3
0
/*
 * Create an ISA DMA map.
 */
int
_isa_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 i386_isa_dma_cookie *cookie;
	bus_dmamap_t map;
	int error, cookieflags;
	void *cookiestore;
	size_t cookiesize;

	/* Call common function to create the basic map. */
	error = _bus_dmamap_create(t, size, nsegments, maxsegsz, boundary,
	    flags, dmamp);
	if (error)
		return (error);

	map = *dmamp;
	map->_dm_cookie = NULL;

	cookiesize = sizeof(struct i386_isa_dma_cookie);

	/*
	 * ISA only has 24-bits of address space.  This means
	 * we can't DMA to pages over 16M.  In order to DMA to
	 * arbitrary buffers, we use "bounce buffers" - pages
	 * in memory below the 16M boundary.  On DMA reads,
	 * DMA happens to the bounce buffers, and is copied into
	 * the caller's buffer.  On writes, data is copied into
	 * but bounce buffer, and the DMA happens from those
	 * pages.  To software using the DMA mapping interface,
	 * this looks simply like a data cache.
	 *
	 * If we have more than 16M of RAM in the system, we may
	 * need bounce buffers.  We check and remember that here.
	 *
	 * There are exceptions, however.  VLB devices can do
	 * 32-bit DMA, and indicate that here.
	 *
	 * ...or, there is an opposite case.  The most segments
	 * a transfer will require is (maxxfer / NBPG) + 1.  If
	 * the caller can't handle that many segments (e.g. the
	 * ISA DMA controller), we may have to bounce it as well.
	 */
	cookieflags = 0;
	if ((avail_end > ISA_DMA_BOUNCE_THRESHOLD &&
	    (flags & ISABUS_DMA_32BIT) == 0) ||
	    ((map->_dm_size / NBPG) + 1) > map->_dm_segcnt) {
		cookieflags |= ID_MIGHT_NEED_BOUNCE;
		cookiesize += (sizeof(bus_dma_segment_t) * map->_dm_segcnt);
	}

	/*
	 * Allocate our cookie.
	 */
	if ((cookiestore = malloc(cookiesize, M_DEVBUF,
	    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK)) == NULL) {
		error = ENOMEM;
		goto out;
	}
	bzero(cookiestore, cookiesize);
	cookie = (struct i386_isa_dma_cookie *)cookiestore;
	cookie->id_flags = cookieflags;
	map->_dm_cookie = cookie;

	if (cookieflags & ID_MIGHT_NEED_BOUNCE) {
		/*
		 * Allocate the bounce pages now if the caller
		 * wishes us to do so.
		 */
		if ((flags & BUS_DMA_ALLOCNOW) == 0)
			goto out;

		error = _isa_dma_alloc_bouncebuf(t, map, size, flags);
	}

 out:
	if (error) {
		if (map->_dm_cookie != NULL)
			free(map->_dm_cookie, M_DEVBUF);
		_bus_dmamap_destroy(t, map);
	}
	return (error);
}
Beispiel #4
0
/*
 * Load an ISA DMA map with a linear buffer.
 */
int
_isa_bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
	bus_size_t buflen, struct proc *p, int flags)
{
	struct powerpc_isa_dma_cookie *cookie = map->_dm_cookie;
	int error;

	STAT_INCR(isa_dma_stats_loads);

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

	/*
	 * Try to load the map the normal way.  If this errors out,
	 * and we can bounce, we will.
	 */
	error = _bus_dmamap_load(t, map, buf, buflen, p, flags);
	if (error == 0 ||
	    (error != 0 && (cookie->id_flags & ID_MIGHT_NEED_BOUNCE) == 0))
		return (error);

	/*
	 * First attempt failed; bounce it.
	 */

	STAT_INCR(isa_dma_stats_bounces);

	/*
	 * Allocate bounce pages, if necessary.
	 */
	if ((cookie->id_flags & ID_HAS_BOUNCE) == 0) {
		error = _isa_dma_alloc_bouncebuf(t, map, buflen, flags);
		if (error)
			return (error);
	}

	/*
	 * Cache a pointer to the caller's buffer and load the DMA map
	 * with the bounce buffer.
	 */
	cookie->id_origbuf = buf;
	cookie->id_origbuflen = buflen;
	cookie->id_buftype = ID_BUFTYPE_LINEAR;
	error = _bus_dmamap_load(t, map, cookie->id_bouncebuf, buflen,
	    p, flags);
	if (error) {
		/*
		 * Free the bounce pages, unless our resources
		 * are reserved for our exclusive use.
		 */
		if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
			_isa_dma_free_bouncebuf(t, map);
		return (error);
	}

	/* ...so _isa_bus_dmamap_sync() knows we're bouncing */
	cookie->id_flags |= ID_IS_BOUNCING;
	return (0);
}