Implement bus_dmamem_alloc_size() and bus_dmamem_free_size() as

counterparts to bus_dmamem_alloc() and bus_dmamem_free().  This allows
the caller to specify the size of the allocation instead of it defaulting
to the max_size field of the busdma tag.

This is intended to aid in converting drivers to busdma.  Lots of
hardware cannot understand scatter/gather lists, which forces the
driver to copy the i/o buffers to a single contiguous region
before sending it to the hardware.  Without these new methods, this
would require a new busdma tag for each operation, or a complex
internal allocator/cache for each driver.

Allocations greater than PAGE_SIZE are rounded up to the next
PAGE_SIZE by contigmalloc(), so this is not suitable for multiple
static allocations that would be better served by a single
fixed-length subdivided allocation.

Reviewed by:	jake (sparc64)

1 files changed, 30 insertions, 0 deletions

diff --git a/sys/sparc64/include/bus.h b/sys/sparc64/include/bus.h
index 95089fa..2a90c01 100644
--- a/sys/sparc64/include/bus.h
+++ b/sys/sparc64/include/bus.h
@@ -971,8 +971,12 @@ struct bus_dma_tag {
 	/*
 	 * DMA memory utility functions.
 	 */
+	int	(*dt_dmamem_alloc_size)(bus_dma_tag_t, bus_dma_tag_t, void **,
+	    int, bus_dmamap_t *, bus_size_t size);
 	int	(*dt_dmamem_alloc)(bus_dma_tag_t, bus_dma_tag_t, void **, int,
 	    bus_dmamap_t *);
+	void	(*dt_dmamem_free_size)(bus_dma_tag_t, bus_dma_tag_t, void *,
+	    bus_dmamap_t, bus_size_t size);
 	void	(*dt_dmamem_free)(bus_dma_tag_t, bus_dma_tag_t, void *,
 	    bus_dmamap_t);
 };
@@ -1084,6 +1088,19 @@ sparc64_dmamap_sync(bus_dma_tag_t pt, bus_dma_tag_t dt, bus_dmamap_t m,
 	sparc64_dmamap_sync((t), (t), (m), (op))
 
 static __inline int
+sparc64_dmamem_alloc_size(bus_dma_tag_t pt, bus_dma_tag_t dt, void **v, int f,
+    bus_dmamap_t *m, bus_size_t s)
+{
+	bus_dma_tag_t lt;
+
+	for (lt = pt; lt->dmamem_alloc == NULL; lt = lt->parent)
+		;
+	return ((*lt->dmamem_alloc_size)(lt, dt, v, f, m, s));
+}
+#define	bus_dmamem_alloc_size(t, v, f, m, s)				\
+	sparc64_dmamem_alloc_size((t), (t), (v), (f), (m), (s))
+
+static __inline int
 sparc64_dmamem_alloc(bus_dma_tag_t pt, bus_dma_tag_t dt, void **v, int f,
     bus_dmamap_t *m)
 {
@@ -1097,6 +1114,19 @@ sparc64_dmamem_alloc(bus_dma_tag_t pt, bus_dma_tag_t dt, void **v, int f,
 	sparc64_dmamem_alloc((t), (t), (v), (f), (m))
 
 static __inline void
+sparc64_dmamem_free_size(bus_dma_tag_t pt, bus_dma_tag_t dt, void *v,
+    bus_dmamap_t m, bus_size_t s)
+{
+	bus_dma_tag_t lt;
+
+	for (lt = pt; lt->dmamem_free == NULL; lt = lt->parent)
+		;
+	(*lt->dmamem_free_size)(lt, dt, v, m, s);
+}
+#define	bus_dmamem_free_size(t, v, m, s)				\
+	sparc64_dmamem_free_size((t), (t), (v), (m), (s))
+
+static __inline void
 sparc64_dmamem_free(bus_dma_tag_t pt, bus_dma_tag_t dt, void *v,
     bus_dmamap_t m)
 {