From: Rob Clark <rob@xxxxxx>
Add some helpers to iterate through all attachers and get the most
restrictive segment size/count/boundary.
Signed-off-by: Rob Clark <rob@xxxxxx>
---
drivers/base/dma-buf.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/dma-buf.h | 19 ++++++++++++++
2 files changed, 82 insertions(+)
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 24e88fe..757ee20 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -192,6 +192,69 @@ void dma_buf_put(struct dma_buf *dmabuf)
EXPORT_SYMBOL_GPL(dma_buf_put);
/**
+ * dma_buf_max_seg_size - helper for exporters to get the minimum of
+ * all attached device's max segment size
+ */
+unsigned int dma_buf_max_seg_size(struct dma_buf *dmabuf)
+{
+ struct dma_buf_attachment *attach;
+ unsigned int max = (unsigned int)-1;
+
+ if (WARN_ON(!dmabuf))
+ return 0;
+
+ mutex_lock(&dmabuf->lock);
+ list_for_each_entry(attach, &dmabuf->attachments, node)
+ max = min(max, dma_get_max_seg_size(attach->dev));
+ mutex_unlock(&dmabuf->lock);
+
+ return max;
+}
+EXPORT_SYMBOL_GPL(dma_buf_max_seg_size);
+
+/**
+ * dma_buf_max_seg_count - helper for exporters to get the minimum of
+ * all attached device's max segment count
+ */
+unsigned int dma_buf_max_seg_count(struct dma_buf *dmabuf)
+{
+ struct dma_buf_attachment *attach;
+ unsigned int max = (unsigned int)-1;
+
+ if (WARN_ON(!dmabuf))
+ return 0;
+
+ mutex_lock(&dmabuf->lock);
+ list_for_each_entry(attach, &dmabuf->attachments, node)
+ max = min(max, dma_get_max_seg_count(attach->dev));
+ mutex_unlock(&dmabuf->lock);
+
+ return max;
+}
+EXPORT_SYMBOL_GPL(dma_buf_max_seg_count);
+
+/**
+ * dma_buf_get_seg_boundary - helper for exporters to get the most
+ * restrictive segment alignment of all the attached devices
+ */
+unsigned int dma_buf_get_seg_boundary(struct dma_buf *dmabuf)
+{
+ struct dma_buf_attachment *attach;
+ unsigned int mask = (unsigned int)-1;
+
+ if (WARN_ON(!dmabuf))
+ return 0;
+
+ mutex_lock(&dmabuf->lock);
+ list_for_each_entry(attach, &dmabuf->attachments, node)
+ mask &= dma_get_seg_boundary(attach->dev);
+ mutex_unlock(&dmabuf->lock);
+
+ return mask;
+}
+EXPORT_SYMBOL_GPL(dma_buf_get_seg_boundary);
+
+/**
* dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
* calls attach() of dma_buf_ops to allow device-specific attach functionality
* @dmabuf: [in] buffer to attach device to.
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index eb48f38..9533b9b 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -167,6 +167,10 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags);
struct dma_buf *dma_buf_get(int fd);
void dma_buf_put(struct dma_buf *dmabuf);
+unsigned int dma_buf_max_seg_size(struct dma_buf *dmabuf);
+unsigned int dma_buf_max_seg_count(struct dma_buf *dmabuf);
+unsigned int dma_buf_get_seg_boundary(struct dma_buf *dmabuf);
+
struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
enum dma_data_direction);
void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
@@ -220,6 +224,21 @@ static inline void dma_buf_put(struct dma_buf *dmabuf)
return;
}
+static inline unsigned int dma_buf_max_seg_size(struct dma_buf *dmabuf)
+{
+ return 0;
+}
+
+static inline unsigned int dma_buf_max_seg_count(struct dma_buf *dmabuf)
+{
+ return 0;
+}
+
+static inline unsigned int dma_buf_get_seg_boundary(struct dma_buf *dmabuf)
+{
+ return 0;
+}
+
static inline struct sg_table *dma_buf_map_attachment(
struct dma_buf_attachment *attach, enum dma_data_direction write)
{
--
1.7.9.5
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