Hello, On 2015-12-13 20:57, Laurent Pinchart wrote:
Hi Marek, Thank you for the patch. On Wednesday 09 December 2015 14:58:19 Marek Szyprowski wrote: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> --- 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 c331272..628518d 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) {When can this function be called with dev->dma_parms not NULL ?
When one loads a module with multimedia driver (which calls this function), then
unloads and loads it again. It is rather safe to have this check.
+ 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 c33dfa6..0e6ba64 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;
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
