Re: [PATCH 2/4] iommu: Implement common IOMMU ops for DMA mapping
Hi Robin,
More info, hope this make it clearer. We are calling dma_map_sg_attrs
with the following 2 sg. With IOMMU, we are expecting it got merged into
1 contiguous va range, but instead we get 2 va range.
sg0 dma_address 0xfeeddc00 size 0x400, offset 0xc00
sg1 dma_address 0xfeede000 size 0x1000, offset 0x0
Joe.C
On Fri, 2015-05-29 at 13:26 +0800, Yong Wu wrote:
Hi Robin,
Thanks.
While we test venc in v4l2, we get a problem:
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.
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 robin.mur...@arm.com
---
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;
+ sg_dma_address(seg) = dma_addr + s_offset;
Here the value of sg_dma_address have added s_offset, but
sg_dma_len(seg) still is s_dma_len.
In the first loop, s_dma_len is from s-length which is alignd by
s_length = iova_align(iovad, s_length + s_offset); in
the interface iommu_dma_map_sg.
+
+ seg_len = s_offset;
+ seg_dma = dma_addr + s_offset;
+ }
+ seg_len += s_length;
+ dma_addr += s_dma_len;
+ }
+ return count;
+}
+
+static void __invalidate_sg(struct scatterlist *sg, int nents)
+{
+ struct scatterlist *s;
+ int i;
+
+ for_each_sg(sg, s, nents, i) {
+ if (sg_dma_address(s) != DMA_ERROR_CODE)
+ s-offset = sg_dma_address(s);
+ if (sg_dma_len(s))
+ s-length = sg_dma_len(s);
+ sg_dma_address(s) = DMA_ERROR_CODE;
+ sg_dma_len(s) = 0;
+ }
+}
+
+int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
+ int nents, int prot, bool coherent)
+{
+ struct iommu_dma_domain *dom = arch_get_dma_domain(dev);
+ struct iova_domain *iovad = dom-iovad;
+ struct iova *iova;
+ struct scatterlist *s;
+ dma_addr_t dma_addr;
+ size_t iova_len = 0;
+ int i;
+
+ /*
+* Work out how much IOVA space we need, and align the segments to
+* IOVA granules for the IOMMU driver to handle. With some clever
+* trickery we can modify the list in a reversible manner.
+*/
+ for_each_sg(sg, s, nents, i) {
+ size_t s_offset = iova_offset(iovad, s-offset);
+ size_t s_length = s-length;
+
+ sg_dma_address(s) = s-offset;
+ sg_dma_len(s) = s_length;
+ s-offset -= s_offset;
+ s_length = iova_align(iovad, s_length + s_offset);
+ s-length =
Re: [PATCH 2/4] iommu: Implement common IOMMU ops for DMA mapping
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 robin.mur...@arm.com
---
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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Re: [PATCH 2/4] iommu: Implement common IOMMU ops for DMA mapping
Hi Robin,
Thanks.
While we test venc in v4l2, we get a problem:
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.
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 robin.mur...@arm.com
---
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;
+ sg_dma_address(seg) = dma_addr + s_offset;
Here the value of sg_dma_address have added s_offset, but
sg_dma_len(seg) still is s_dma_len.
In the first loop, s_dma_len is from s-length which is alignd by
s_length = iova_align(iovad, s_length + s_offset); in
the interface iommu_dma_map_sg.
+
+ seg_len = s_offset;
+ seg_dma = dma_addr + s_offset;
+ }
+ seg_len += s_length;
+ dma_addr += s_dma_len;
+ }
+ return count;
+}
+
+static void __invalidate_sg(struct scatterlist *sg, int nents)
+{
+ struct scatterlist *s;
+ int i;
+
+ for_each_sg(sg, s, nents, i) {
+ if (sg_dma_address(s) != DMA_ERROR_CODE)
+ s-offset = sg_dma_address(s);
+ if (sg_dma_len(s))
+ s-length = sg_dma_len(s);
+ sg_dma_address(s) = DMA_ERROR_CODE;
+ sg_dma_len(s) = 0;
+ }
+}
+
+int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
+ int nents, int prot, bool coherent)
+{
+ struct iommu_dma_domain *dom = arch_get_dma_domain(dev);
+ struct iova_domain *iovad = dom-iovad;
+ struct iova *iova;
+ struct scatterlist *s;
+ dma_addr_t dma_addr;
+ size_t iova_len = 0;
+ int i;
+
+ /*
+ * Work out how much IOVA space we need, and align the segments to
+ * IOVA granules for the IOMMU driver to handle. With some clever
+ * trickery we can modify the list in a reversible manner.
+ */
+ for_each_sg(sg, s, nents, i) {
+ size_t s_offset = iova_offset(iovad, s-offset);
+ size_t s_length = s-length;
+
+ sg_dma_address(s) = s-offset;
+ sg_dma_len(s) = s_length;
+ s-offset -= s_offset;
+ s_length = iova_align(iovad, s_length + s_offset);
+ s-length = s_length;
At the begging, s-length is the length of valid data. but it's aligned
here.
+
+ iova_len += s_length;
+ }
+
+ iova = __alloc_iova(dev, iova_len, coherent);
+ if (!iova)
+ goto out_restore_sg;
+
+ /*
+ * We'll leave any physical concatenation to the IOMMU driver's
+ * implementation - it
