From cf1c1c1da8c6d059c2da40ca12ab119a96d6b55a Mon Sep 17 00:00:00 2001
From: Sricharan R <sricharan@codeaurora.org>
Date: Fri, 12 Jul 2019 09:47:15 +0800
Subject: [PATCH] dmaengine: qcom: bam_dma: Fix completed descriptors count

commit f6034225442c4a87906d36e975fd9e99a8f95487 upstream.

One space is left unused in circular FIFO to differentiate
'full' and 'empty' cases. So take that in to account while
counting for the descriptors completed.

Fixes the issue reported here,
	https://lkml.org/lkml/2019/6/18/669

Cc: stable@vger.kernel.org
Reported-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/dma/qcom/bam_dma.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 1617715aa6e0..489c8fa4d2e2 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -808,6 +808,9 @@ static u32 process_channel_irqs(struct bam_device *bdev)
 		/* Number of bytes available to read */
 		avail = CIRC_CNT(offset, bchan->head, MAX_DESCRIPTORS + 1);
 
+		if (offset < bchan->head)
+			avail--;
+
 		list_for_each_entry_safe(async_desc, tmp,
 					 &bchan->desc_list, desc_node) {
 			/* Not enough data to read */
-- 
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