Technically, calling dma_buf_map_attachment should return a buffer
properly dma_mapped. Add calls to dma_map_sg to begin_cpu_access to
ensure this happens. As a side effect, this lets Ion buffers take
advantage of the dma_buf sync ioctls.

Not-signed-off-by: Laura Abbott <labb...@redhat.com>
---
 drivers/staging/android/ion/ion.c | 61 ++++++++++++++++++++++++++++++---------
 1 file changed, 47 insertions(+), 14 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c 
b/drivers/staging/android/ion/ion.c
index 86dba07..5177d79 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -776,6 +776,11 @@ static struct sg_table *dup_sg_table(struct sg_table 
*table)
        return new_table;
 }
 
+static void free_duped_table(struct sg_table *table)
+{
+       sg_free_table(table);
+       kfree(table);
+}
 
 static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,
                                        enum dma_data_direction direction)
@@ -784,15 +789,29 @@ static struct sg_table *ion_map_dma_buf(struct 
dma_buf_attachment *attachment,
        struct ion_buffer *buffer = dmabuf->priv;
        struct sg_table *table;
 
-       return dup_sg_table(buffer->sg_table);
+       /*
+        * TODO: Need to sync wrt CPU or device completely owning?
+        */
+
+       table = dup_sg_table(buffer->sg_table);
+
+       if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
+                       direction)){
+               ret = -ENOMEM;
+               goto err;
+       }
+
+err:
+       free_duped_table(table);
+       return ERR_PTR(ret);
 }
 
 static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
                              struct sg_table *table,
                              enum dma_data_direction direction)
 {
-       sg_free_table(table);
-       kfree(table);
+       dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
+       free_duped_table(table);
 }
 
 struct ion_vma_list {
@@ -889,16 +908,24 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf 
*dmabuf,
        struct ion_buffer *buffer = dmabuf->priv;
        void *vaddr;
 
-       if (!buffer->heap->ops->map_kernel) {
-               pr_err("%s: map kernel is not implemented by this heap.\n",
-                      __func__);
-               return -ENODEV;
+       /*
+        * TODO: Move this elsewhere because we don't always need a vaddr
+        */
+       if (buffer->heap->ops->map_kernel) {
+               mutex_lock(&buffer->lock);
+               vaddr = ion_buffer_kmap_get(buffer);
+               mutex_unlock(&buffer->lock);
        }
 
-       mutex_lock(&buffer->lock);
-       vaddr = ion_buffer_kmap_get(buffer);
-       mutex_unlock(&buffer->lock);
-       return PTR_ERR_OR_ZERO(vaddr);
+       /*
+        * Close enough right now? Flag to skip sync?
+        */
+       if (!dma_map_sg(buffer->dev->dev.this_device, buffer->sg_table->sgl,
+                       buffer->sg_table->nents,
+                        DMA_BIDIRECTIONAL))
+               return -ENOMEM;
+
+       return 0;
 }
 
 static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
@@ -906,9 +933,15 @@ static int ion_dma_buf_end_cpu_access(struct dma_buf 
*dmabuf,
 {
        struct ion_buffer *buffer = dmabuf->priv;
 
-       mutex_lock(&buffer->lock);
-       ion_buffer_kmap_put(buffer);
-       mutex_unlock(&buffer->lock);
+       if (buffer->heap->ops->map_kernel) {
+               mutex_lock(&buffer->lock);
+               ion_buffer_kmap_put(buffer);
+               mutex_unlock(&buffer->lock);
+       }
+
+       dma_unmap_sg(buffer->dev->dev.this_device, buffer->sg_table->sgl,
+                       buffer->sg_table->nents,
+                       DMA_BIDIRECTIONAL);
 
        return 0;
 }
-- 
2.7.4

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