The IOMMU virtual memory mapping API requires page-aligned buffers.
There's no hardware reason behind such a restriction. Remove it by
rounding the address of the first page entry down, and adding the offset
back to the IOMMU virtual address.
Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
---
arch/arm/plat-omap/iovmm.c | 32 ++++++++++++++++++++++++--------
1 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/arch/arm/plat-omap/iovmm.c b/arch/arm/plat-omap/iovmm.c
index 663e2d2..7d63f98 100644
--- a/arch/arm/plat-omap/iovmm.c
+++ b/arch/arm/plat-omap/iovmm.c
@@ -59,6 +59,15 @@
static struct kmem_cache *iovm_area_cachep;
+/* return the offset of the first scatterlist entry in a sg table */
+static unsigned int sgtable_offset(const struct sg_table *sgt)
+{
+ if (!sgt || !sgt->nents)
+ return 0;
+
+ return sgt->sgl->offset;
+}
+
/* return total bytes of sg buffers */
static size_t sgtable_len(const struct sg_table *sgt)
{
@@ -71,11 +80,17 @@ static size_t sgtable_len(const struct sg_table *sgt)
for_each_sg(sgt->sgl, sg, sgt->nents, i) {
size_t bytes;
- bytes = sg_dma_len(sg);
+ bytes = sg_dma_len(sg) + sg->offset;
if (!iopgsz_ok(bytes)) {
- pr_err("%s: sg[%d] not iommu pagesize(%x)\n",
- __func__, i, bytes);
+ pr_err("%s: sg[%d] not iommu pagesize(%u %u)\n",
+ __func__, i, bytes, sg->offset);
+ return 0;
+ }
+
+ if (i && sg->offset) {
+ pr_err("%s: sg[%d] offset not allowed in internal "
+ "entries\n", __func__, i);
return 0;
}
@@ -197,8 +212,8 @@ static void *vmap_sg(const struct sg_table *sgt)
u32 pa;
int err;
- pa = sg_phys(sg);
- bytes = sg_dma_len(sg);
+ pa = sg_phys(sg) - sg->offset;
+ bytes = sg_dma_len(sg) + sg->offset;
BUG_ON(bytes != PAGE_SIZE);
@@ -467,8 +482,8 @@ static int map_iovm_area(struct iommu *obj, struct
iovm_struct *new,
size_t bytes;
struct iotlb_entry e;
- pa = sg_phys(sg);
- bytes = sg_dma_len(sg);
+ pa = sg_phys(sg) - sg->offset;
+ bytes = sg_dma_len(sg) + sg->offset;
flags &= ~IOVMF_PGSZ_MASK;
pgsz = bytes_to_iopgsz(bytes);
@@ -649,7 +664,7 @@ u32 iommu_vmap(struct iommu *obj, u32 da, const struct
sg_table *sgt,
if (IS_ERR_VALUE(da))
vunmap_sg(va);
- return da;
+ return da + sgtable_offset(sgt);
}
EXPORT_SYMBOL_GPL(iommu_vmap);
@@ -668,6 +683,7 @@ struct sg_table *iommu_vunmap(struct iommu *obj, u32 da)
* 'sgt' is allocated before 'iommu_vmalloc()' is called.
* Just returns 'sgt' to the caller to free
*/
+ da &= PAGE_MASK;
sgt = unmap_vm_area(obj, da, vunmap_sg, IOVMF_DISCONT | IOVMF_MMIO);
if (!sgt)
dev_dbg(obj->dev, "%s: No sgt\n", __func__);
--
1.6.4.4
--
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