On 04/27/2016 02:00 PM, 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> > --- > This patch was posted earlier as a part of > http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/97316 > thread, but applying it is really needed to get all Exynos multimedia > drivers working with IOMMU enabled. > > Best regards, > Marek Szyprowski > --- > 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 5361197..f611456 100644 > --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c > +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c > @@ -753,6 +753,21 @@ 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); The v3 patch from December uses kzalloc here. Is this perhaps on old version? > + 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); Admittedly I haven't looked closely at this, but is this something that you want for all dma-contig devices? Or to rephrase this question: what type of devices will need this? Regards, Hans > + > 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 2087c9a..98857b5 100644 > --- a/include/media/videobuf2-dma-contig.h > +++ b/include/media/videobuf2-dma-contig.h > @@ -35,6 +35,7 @@ static inline 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; > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
