[PATCH AUTOSEL 5.12 04/39] dmaengine: xilinx: dpdma: Limit descriptor IDs to 16 bits

Sasha Levin
2021-06-21T17:52:20Z

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

[ Upstream commit 9f007e7b6643799e2a6538a5fe04f51c371c6657 ]

While the descriptor ID is stored in a 32-bit field in the hardware
descriptor, only 16 bits are used by the hardware and are reported
through the XILINX_DPDMA_CH_DESC_ID register. Failure to handle the
wrap-around results in a descriptor ID mismatch after 65536 frames. Fix
it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Reviewed-by: Jianqiang Chen <jianqiang.chen@xilinx.com>
Link: https://lore.kernel.org/r/20210520152420.23986-5-laurent.pinchart@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/xilinx/xilinx_dpdma.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index 70b29bd079c9..249ce3988a59 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -113,6 +113,7 @@
#define XILINX_DPDMA_CH_VDO 0x020
#define XILINX_DPDMA_CH_PYLD_SZ 0x024
#define XILINX_DPDMA_CH_DESC_ID 0x028
+#define XILINX_DPDMA_CH_DESC_ID_MASK GENMASK(15, 0)

/* DPDMA descriptor fields */
#define XILINX_DPDMA_DESC_CONTROL_PREEMBLE 0xa5
@@ -866,7 +867,8 @@ static void xilinx_dpdma_chan_queue_transfer(struct xilinx_dpdma_chan *chan)
* will be used, but it should be enough.
*/
list_for_each_entry(sw_desc, &desc->descriptors, node)
- sw_desc->hw.desc_id = desc->vdesc.tx.cookie;
+ sw_desc->hw.desc_id = desc->vdesc.tx.cookie
+ & XILINX_DPDMA_CH_DESC_ID_MASK;

sw_desc = list_first_entry(&desc->descriptors,
struct xilinx_dpdma_sw_desc, node);
@@ -1086,7 +1088,8 @@ static void xilinx_dpdma_chan_vsync_irq(struct xilinx_dpdma_chan *chan)
if (!chan->running || !pending)
goto out;

- desc_id = dpdma_read(chan->reg, XILINX_DPDMA_CH_DESC_ID);
+ desc_id = dpdma_read(chan->reg, XILINX_DPDMA_CH_DESC_ID)
+ & XILINX_DPDMA_CH_DESC_ID_MASK;

/* If the retrigger raced with vsync, retry at the next frame. */
sw_desc = list_first_entry(&pending->descriptors,
--
2.30.2