Add a helper function for device drivers to set DMA's max_seg_size.
Setting it to largest possible value lets DMA-mapping API always create
contiguous mappings in DMA address space. This is essential for all
devices, which use dma-contig videobuf2 memory allocator and shared
buffers.
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
Changelog:
v3:
- make this code a helper function instead of chaning max_seg_size
unconditionally on vb2_dma_contig_init_ctx
v2:
- set max segment size only if a new dma params structure has been
allocated, as suggested by Laurent Pinchart
---
drivers/media/v4l2-core/videobuf2-dma-contig.c | 15 +++++++++++++++
include/media/videobuf2-dma-contig.h | 1 +
2 files changed, 16 insertions(+)
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index c33127284cfe..628518dc3aad 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -742,6 +742,21 @@ void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
}
EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
+int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size)
+{
+ if (!dev->dma_parms) {
+ dev->dma_parms = devm_kzalloc(dev, sizeof(dev->dma_parms),
+ GFP_KERNEL);
+ if (!dev->dma_parms)
+ return -ENOMEM;
+ }
+ if (dma_get_max_seg_size(dev) < size)
+ return dma_set_max_seg_size(dev, size);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(vb2_dma_contig_set_max_seg_size);
+
MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
MODULE_AUTHOR("Pawel Osciak <pawel@xxxxxxxxxx>");
MODULE_LICENSE("GPL");
diff --git a/include/media/videobuf2-dma-contig.h b/include/media/videobuf2-dma-contig.h
index c33dfa69d7ab..0e6ba644939e 100644
--- a/include/media/videobuf2-dma-contig.h
+++ b/include/media/videobuf2-dma-contig.h
@@ -26,6 +26,7 @@ vb2_dma_contig_plane_dma_addr(struct vb2_buffer *vb, unsigned int plane_no)
void *vb2_dma_contig_init_ctx(struct device *dev);
void vb2_dma_contig_cleanup_ctx(void *alloc_ctx);
+int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size);
extern const struct vb2_mem_ops vb2_dma_contig_memops;
--
1.9.2
--
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