- Introduce a new busdma flag BUS_DMA_ZERO to request for zero'ed

  memory in bus_dmamem_alloc().  This is possible now that
  contigmalloc() supports the M_ZERO flag.
- Remove the locking of Giant around calls to contigmalloc() since
  contigmalloc() now grabs Giant itself.

2 files changed, 12 insertions, 6 deletions

diff --git a/sys/powerpc/include/bus.h b/sys/powerpc/include/bus.h
index 3ee2de5..bb5f357 100644
--- a/sys/powerpc/include/bus.h
+++ b/sys/powerpc/include/bus.h
@@ -744,6 +744,7 @@ bus_space_set_region_stream_4(bus_space_tag_t tag, bus_space_handle_t bsh,
 #define	BUS_DMA_NOWAIT		0x01	/* not safe to sleep */
 #define	BUS_DMA_ALLOCNOW	0x02	/* perform resource allocation now */
 #define	BUS_DMA_COHERENT	0x04	/* hint: map memory DMA coherent */
+#define	BUS_DMA_ZERO		0x08	/* allocate zero'ed memory */
 #define	BUS_DMA_BUS1		0x10	/* placeholders for bus functions... */
 #define	BUS_DMA_BUS2		0x20
 #define	BUS_DMA_BUS3		0x40
diff --git a/sys/powerpc/powerpc/busdma_machdep.c b/sys/powerpc/powerpc/busdma_machdep.c
index f3ef3e3..829d29ab 100644
--- a/sys/powerpc/powerpc/busdma_machdep.c
+++ b/sys/powerpc/powerpc/busdma_machdep.c
@@ -254,23 +254,28 @@ int
 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
                  bus_dmamap_t *mapp)
 {
+	int mflags;
+
+	if (flags & BUS_DMA_NOWAIT)
+		mflags = M_NOWAIT;
+	else
+		mflags = M_WAITOK;
+	if (flags & BUS_DMA_ZERO)
+		mflags |= M_ZERO;
+
         *mapp = NULL;
 	
         if (dmat->maxsize <= PAGE_SIZE) {
-                *vaddr = malloc(dmat->maxsize, M_DEVBUF,
-                             (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK);
+                *vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
         } else {
                 /*
                  * XXX Use Contigmalloc until it is merged into this facility
                  *     and handles multi-seg allocations.  Nobody is doing
                  *     multi-seg allocations yet though.
                  */
-		mtx_lock(&Giant);
-                *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF,
-                    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK,
+                *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
                     dmat->boundary);
-		mtx_unlock(&Giant);
         }
 
         if (*vaddr == NULL)