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

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

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From a197f3c7d48c0c1f45076ea47533a76ba9b1a959 Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Fri, 18 Mar 2016 14:26:33 +0200
Subject: dmaengine: hsu: correct residue calculation of active descriptor

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

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.

Fixes: f0579c8ceaf1 ("dmaengine: hsu: speed up residue calculation")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/dma/hsu/hsu.c
+++ b/drivers/dma/hsu/hsu.c
@@ -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 andriy.shevchenko@linux.intel.com 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