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-rw-r--r--drivers/dma/edma.c26
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 5d9f57f27ffb..18c833fa1646 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -70,12 +70,34 @@ struct edma_desc {
int cyclic;
int absync;
int pset_nr;
+ struct edma_chan *echan;
int processed;
+
+ /*
+ * The following 4 elements are used for residue accounting.
+ *
+ * - processed_stat: the number of SG elements we have traversed
+ * so far to cover accounting. This is updated directly to processed
+ * during edma_callback and is always <= processed, because processed
+ * refers to the number of pending transfer (programmed to EDMA
+ * controller), where as processed_stat tracks number of transfers
+ * accounted for so far.
+ *
+ * - residue: The amount of bytes we have left to transfer for this desc
+ *
+ * - residue_stat: The residue in bytes of data we have covered
+ * so far for accounting. This is updated directly to residue
+ * during callbacks to keep it current.
+ *
+ * - sg_len: Tracks the length of the current intermediate transfer,
+ * this is required to update the residue during intermediate transfer
+ * completion callback.
+ */
int processed_stat;
- u32 residue;
u32 sg_len;
+ u32 residue;
u32 residue_stat;
- struct edma_chan *echan;
+
struct edma_pset pset[0];
};