Patch "dmaengine: hsu: correct residue calculation of active descriptor" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

dmaengine: hsu: correct residue calculation of active descriptor

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
dmaengine-hsu-correct-residue-calculation-of-active-descriptor.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Andy Shevchenko <[email protected]>
Date: Fri, 18 Mar 2016 14:26:33 +0200
Subject: dmaengine: hsu: correct residue calculation of active descriptor

From: Andy Shevchenko <[email protected]>

commit a197f3c7d48c0c1f45076ea47533a76ba9b1a959 upstream.

The commit f0579c8ceaf1 ("dmaengine: hsu: speed up residue calculation") speeded up calculation of the queued descriptor but broke the initial residue value for active descriptor.

In accordance with documentation the hardware descriptor is updated each time DMA transfered some bytes. It means we have to calculate a sum of lengths of non-submitted hardware descriptors and whatever current values in the hardware. Do this straightforward.

---
 drivers/dma/hsu/hsu.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

@@ -254,10 +254,13 @@ static void hsu_dma_issue_pending(struct
 static size_t hsu_dma_active_desc_size(struct hsu_dma_chan *hsuc)
 {
 	struct hsu_dma_desc *desc = hsuc->desc;
-	size_t bytes = desc->length;
+	size_t bytes = 0;
 	int i;
 
-	i = desc->active % HSU_DMA_CHAN_NR_DESC;
+	for (i = desc->active; i < desc->nents; i++)
+		bytes += desc->sg[i].len;
+
+	i = HSU_DMA_CHAN_NR_DESC - 1;
 	do {
 		bytes += hsu_chan_readl(hsuc, HSU_CH_DxTSR(i));
 	} while (--i >= 0);

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/dmaengine-hsu-correct-use-of-channel-status-register.patch queue-4.5/dmaengine-hsu-correct-residue-calculation-of-active-descriptor.patch queue-4.5/dmaengine-dw-fix-master-selection.patch