/*
* 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);
}
/*
* 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);
}
/*
* 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);
}
/*
* 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);
}