[PATCH 2/3] dmaeninge: xilinx_dma: Fix bug in multiple frame stores scenario in vdma

From: Kedareswara rao Appana
Date: Thu Dec 15 2016 - 10:27:57 EST


When VDMA is configured for more than one frame in the h/w
for example h/w is configured for n number of frames and user
Submits n number of frames and triggered the DMA using issue_pending API.
In the current driver flow we are submitting one frame at a time
but we should submit all the n number of frames at one time as the h/w
Is configured for n number of frames.

This patch fixes this issue.

Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx>
---
drivers/dma/xilinx/xilinx_dma.c | 43 +++++++++++++++++++++++++----------------
1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index 736c2a3..4f3fa94 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -1087,23 +1087,33 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan)
tail_segment->phys);
} else {
struct xilinx_vdma_tx_segment *segment, *last = NULL;
- int i = 0;
+ int i = 0, j = 0;

if (chan->desc_submitcount < chan->num_frms)
i = chan->desc_submitcount;

- list_for_each_entry(segment, &desc->segments, node) {
- if (chan->ext_addr)
- vdma_desc_write_64(chan,
- XILINX_VDMA_REG_START_ADDRESS_64(i++),
- segment->hw.buf_addr,
- segment->hw.buf_addr_msb);
- else
- vdma_desc_write(chan,
- XILINX_VDMA_REG_START_ADDRESS(i++),
- segment->hw.buf_addr);
-
- last = segment;
+ for (j = 0; j < chan->num_frms; ) {
+ list_for_each_entry(segment, &desc->segments, node) {
+ if (chan->ext_addr)
+ vdma_desc_write_64(chan,
+ XILINX_VDMA_REG_START_ADDRESS_64(i++),
+ segment->hw.buf_addr,
+ segment->hw.buf_addr_msb);
+ else
+ vdma_desc_write(chan,
+ XILINX_VDMA_REG_START_ADDRESS(i++),
+ segment->hw.buf_addr);
+
+ last = segment;
+ }
+ list_del(&desc->node);
+ list_add_tail(&desc->node, &chan->active_list);
+ j++;
+ if (list_empty(&chan->pending_list))
+ break;
+ desc = list_first_entry(&chan->pending_list,
+ struct xilinx_dma_tx_descriptor,
+ node);
}

if (!last)
@@ -1114,14 +1124,13 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan)
vdma_desc_write(chan, XILINX_DMA_REG_FRMDLY_STRIDE,
last->hw.stride);
vdma_desc_write(chan, XILINX_DMA_REG_VSIZE, last->hw.vsize);
+
+ chan->desc_submitcount += j;
+ chan->desc_pendingcount -= j;
}

chan->idle = false;
if (!chan->has_sg) {
- list_del(&desc->node);
- list_add_tail(&desc->node, &chan->active_list);
- chan->desc_submitcount++;
- chan->desc_pendingcount--;
if (chan->desc_submitcount == chan->num_frms)
chan->desc_submitcount = 0;
} else {
--
2.1.2