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path: root/drivers/media/video/videobuf-dma-contig.c
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Diffstat (limited to 'drivers/media/video/videobuf-dma-contig.c')
-rw-r--r--drivers/media/video/videobuf-dma-contig.c94
1 files changed, 89 insertions, 5 deletions
diff --git a/drivers/media/video/videobuf-dma-contig.c b/drivers/media/video/videobuf-dma-contig.c
index 6109fb5f34e2..0c29a019bc89 100644
--- a/drivers/media/video/videobuf-dma-contig.c
+++ b/drivers/media/video/videobuf-dma-contig.c
@@ -17,6 +17,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
+#include <linux/pagemap.h>
#include <linux/dma-mapping.h>
#include <media/videobuf-dma-contig.h>
@@ -25,6 +26,7 @@ struct videobuf_dma_contig_memory {
void *vaddr;
dma_addr_t dma_handle;
unsigned long size;
+ int is_userptr;
};
#define MAGIC_DC_MEM 0x0733ac61
@@ -108,6 +110,82 @@ static struct vm_operations_struct videobuf_vm_ops = {
.close = videobuf_vm_close,
};
+/**
+ * videobuf_dma_contig_user_put() - reset pointer to user space buffer
+ * @mem: per-buffer private videobuf-dma-contig data
+ *
+ * This function resets the user space pointer
+ */
+static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
+{
+ mem->is_userptr = 0;
+ mem->dma_handle = 0;
+ mem->size = 0;
+}
+
+/**
+ * videobuf_dma_contig_user_get() - setup user space memory pointer
+ * @mem: per-buffer private videobuf-dma-contig data
+ * @vb: video buffer to map
+ *
+ * This function validates and sets up a pointer to user space memory.
+ * Only physically contiguous pfn-mapped memory is accepted.
+ *
+ * Returns 0 if successful.
+ */
+static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
+ struct videobuf_buffer *vb)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long prev_pfn, this_pfn;
+ unsigned long pages_done, user_address;
+ int ret;
+
+ mem->size = PAGE_ALIGN(vb->size);
+ mem->is_userptr = 0;
+ ret = -EINVAL;
+
+ down_read(&mm->mmap_sem);
+
+ vma = find_vma(mm, vb->baddr);
+ if (!vma)
+ goto out_up;
+
+ if ((vb->baddr + mem->size) > vma->vm_end)
+ goto out_up;
+
+ pages_done = 0;
+ prev_pfn = 0; /* kill warning */
+ user_address = vb->baddr;
+
+ while (pages_done < (mem->size >> PAGE_SHIFT)) {
+ ret = follow_pfn(vma, user_address, &this_pfn);
+ if (ret)
+ break;
+
+ if (pages_done == 0)
+ mem->dma_handle = this_pfn << PAGE_SHIFT;
+ else if (this_pfn != (prev_pfn + 1))
+ ret = -EFAULT;
+
+ if (ret)
+ break;
+
+ prev_pfn = this_pfn;
+ user_address += PAGE_SIZE;
+ pages_done++;
+ }
+
+ if (!ret)
+ mem->is_userptr = 1;
+
+ out_up:
+ up_read(&current->mm->mmap_sem);
+
+ return ret;
+}
+
static void *__videobuf_alloc(size_t size)
{
struct videobuf_dma_contig_memory *mem;
@@ -154,12 +232,11 @@ static int __videobuf_iolock(struct videobuf_queue *q,
case V4L2_MEMORY_USERPTR:
dev_dbg(q->dev, "%s memory method USERPTR\n", __func__);
- /* The only USERPTR currently supported is the one needed for
- read() method.
- */
+ /* handle pointer from user space */
if (vb->baddr)
- return -EINVAL;
+ return videobuf_dma_contig_user_get(mem, vb);
+ /* allocate memory for the read() method */
mem->size = PAGE_ALIGN(vb->size);
mem->vaddr = dma_alloc_coherent(q->dev, mem->size,
&mem->dma_handle, GFP_KERNEL);
@@ -400,7 +477,7 @@ void videobuf_dma_contig_free(struct videobuf_queue *q,
So, it should free memory only if the memory were allocated for
read() operation.
*/
- if ((buf->memory != V4L2_MEMORY_USERPTR) || buf->baddr)
+ if (buf->memory != V4L2_MEMORY_USERPTR)
return;
if (!mem)
@@ -408,6 +485,13 @@ void videobuf_dma_contig_free(struct videobuf_queue *q,
MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+ /* handle user space pointer case */
+ if (buf->baddr) {
+ videobuf_dma_contig_user_put(mem);
+ return;
+ }
+
+ /* read() method */
dma_free_coherent(q->dev, mem->size, mem->vaddr, mem->dma_handle);
mem->vaddr = NULL;
}