On 29/05/15 06:26, Yong Wu wrote:
Hi Robin,
Thanks.
While we test venc in v4l2, we get a problem:
Thanks as always for testing!
When we enter the funtion[0], it will be break unexpectedly in the
funcion[1] while the offset of sg table is not zero. It is ok if the
offset is zero. Then I add more log in dma-iommu.c, please help check
below.
Bah, non-zero offset was about the only scatterlist case I wasn't able
to get out of the EHCI driver...
All we tested it based on dma v2. and have not tested it on v3 yet.
The code of iommu-map-sg seems the same. if it's fixed in v3, I'm very
sorry. The map_sg in mtk-iommu use default_iommu_map_sg.
Any question please tell me, Thanks very much.
[0]http://lxr.free-electrons.com/source/drivers/media/v4l2-core/videobuf2-dma-contig.c#L564
[1]http://lxr.free-electrons.com/source/drivers/media/v4l2-core/videobuf2-dma-contig.c#L70
On Wed, 2015-05-27 at 15:09 +0100, Robin Murphy wrote:
Taking inspiration from the existing arch/arm code, break out some
generic functions to interface the DMA-API to the IOMMU-API. This will
do the bulk of the heavy lifting for IOMMU-backed dma-mapping.
Signed-off-by: Robin Murphy <[email protected]>
---
drivers/iommu/Kconfig | 7 +
drivers/iommu/Makefile | 1 +
drivers/iommu/dma-iommu.c | 560 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/dma-iommu.h | 94 ++++++++
4 files changed, 662 insertions(+)
create mode 100644 drivers/iommu/dma-iommu.c
create mode 100644 include/linux/dma-iommu.h
[snip]
+static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents,
+ dma_addr_t dma_addr)
+{
+ struct scatterlist *s, *seg = sg;
+ unsigned long seg_mask = dma_get_seg_boundary(dev);
+ unsigned int max_len = dma_get_max_seg_size(dev);
+ unsigned int seg_len = 0, seg_dma = 0;
+ int i, count = 1;
+
+ for_each_sg(sg, s, nents, i) {
+ /* Un-swizzling the fields here, hence the naming mismatch */
+ unsigned int s_offset = sg_dma_address(s);
+ unsigned int s_length = sg_dma_len(s);
+ unsigned int s_dma_len = s->length;
+
+ s->offset = s_offset;
+ s->length = s_length;
+ sg_dma_address(s) = DMA_ERROR_CODE;
+ sg_dma_len(s) = 0;
+
+ if (seg_len && (seg_dma + seg_len == dma_addr + s_offset) &&
+ (seg_len + s_dma_len <= max_len) &&
+ ((seg_dma & seg_mask) <= seg_mask - (seg_len + s_length))
+ ) {
+ sg_dma_len(seg) += s_dma_len;
+ } else {
+ if (seg_len) {
+ seg = sg_next(seg);
+ count++;
+ }
+ sg_dma_len(seg) = s_dma_len;
Does changing this to
sg_dma_len(seg) = s_dma_len - s_offset;
make things behave as expected? Since the new unmap code no longer
relies on adding up the individual segments to equal the IOVA size I
don't _think_ that'll break anything here.
Robin.
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