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, 4 insertions, 0 deletions

diff --git a/sys/sparc64/include/iommuvar.h b/sys/sparc64/include/iommuvar.h
index 1052ba3..3c99822 100644
--- a/sys/sparc64/include/iommuvar.h
+++ b/sys/sparc64/include/iommuvar.h
@@ -95,8 +95,12 @@ void iommu_dvmamap_unload(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     bus_dmamap_t);
 void iommu_dvmamap_sync(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     bus_dmamap_t, bus_dmasync_op_t);
+int iommu_dvmamem_alloc_size(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
+    void **, int, bus_dmamap_t *, bus_size_t size);
 int iommu_dvmamem_alloc(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     void **, int, bus_dmamap_t *);
+void iommu_dvmamem_free_size(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
+    void *, bus_dmamap_t, bus_size_t size);
 void iommu_dvmamem_free(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     void *, bus_dmamap_t);