@@ -423,6 +423,39 @@ static inline int vma_is_io(struct vm_area_struct *vma)
return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
}
+static int vb2_dc_get_user_pfn(unsigned long start, int n_pages,
+ struct vm_area_struct *vma, unsigned long *res)
+{
+ unsigned long pfn, start_pfn, prev_pfn;
+ unsigned int i;
+ int ret;
+
+ if (!vma_is_io(vma))
+ return -EFAULT;
+
+ ret = follow_pfn(vma, start, &pfn);
+ if (ret)
+ return ret;
+
+ start_pfn = pfn;
+ start += PAGE_SIZE;
+
+ for (i = 1; i < n_pages; ++i, start += PAGE_SIZE) {
+ prev_pfn = pfn;
+ ret = follow_pfn(vma, start, &pfn);
+
+ if (ret) {
+ pr_err("no page for address %lu\n", start);
+ return ret;
+ }
+ if (pfn != prev_pfn + 1)
+ return -EINVAL;
+ }
+
+ *res = start_pfn;
+ return 0;
+}
+
static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
int n_pages, struct vm_area_struct *vma, int write)
{
@@ -433,6 +466,9 @@ static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
unsigned long pfn;
int ret = follow_pfn(vma, start, &pfn);
+ if (!pfn_valid(pfn))
+ return -EINVAL;
+
if (ret) {
pr_err("no page for address %lu\n", start);
return ret;
@@ -468,16 +504,49 @@ static void vb2_dc_put_userptr(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
- dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
- if (!vma_is_io(buf->vma))
- vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
+ if (sgt) {
+ dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
+ if (!vma_is_io(buf->vma))
+ vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
- sg_free_table(sgt);
- kfree(sgt);
+ sg_free_table(sgt);
+ kfree(sgt);
+ }
vb2_put_vma(buf->vma);
kfree(buf);
}
+/*
+ * For some kind of reserved memory there might be no struct page available,
+ * so all that can be done to support such 'pages' is to try to convert
+ * pfn to dma address or at the last resort just assume that
+ * dma address == physical address (like it has been assumed in earlier version
+ * of videobuf2-dma-contig
+ */
+
+#ifdef __arch_pfn_to_dma
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+ return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
+}
+#elsif defined(__pfn_to_bus)
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+ return (dma_addr_t)__pfn_to_bus(pfn);
+}
+#elsif defined(__pfn_to_phys)
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+ return (dma_addr_t)__pfn_to_phys(pfn);
+}
+#else
+static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
+{
+ /* really, we cannot do anything better at this point */
+ return (dma_addr_t)(pfn) << PAGE_SHIFT;
+}
+#endif
+
static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write)
{
@@ -548,6 +617,14 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
/* extract page list from userspace mapping */
ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
if (ret) {
+ unsigned long pfn;
+ if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {
+ buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn);
+ buf->size = size;
+ kfree(pages);
+ return buf;
+ }
+
pr_err("failed to get user pages\n");
goto fail_vma;
}
Earlier version of dma-contig allocator in user ptr mode assumed that in all cases DMA address equals physical address. This was just a special case. Commit e15dab752d4c588544ccabdbe020a7cc092e23c8 introduced correct support for converting userpage to dma address, but unfortunately it broke the support for simple dma address = physical address for the case, when given physical frame has no struct page associated with it (this happens if one use for example dma_declare_coherent api or other reserved memory approach). This commit restores support for such cases. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- drivers/media/v4l2-core/videobuf2-dma-contig.c | 87 ++++++++++++++++++++++-- 1 file changed, 82 insertions(+), 5 deletions(-)