[PATCH 5.10 187/236] mmc: dw_mmc: Fix issue with uninitialized dma_slave_config

[Greg Kroah-Hartman]

From: Tony Lindgren <tony@xxxxxxxxxxx>

[ Upstream commit c3ff0189d3bc9c03845fe37472c140f0fefd0c79 ]

Depending on the DMA driver being used, the struct dma_slave_config may
need to be initialized to zero for the unused data.

For example, we have three DMA drivers using src_port_window_size and
dst_port_window_size. If these are left uninitialized, it can cause DMA
failures.

For dw_mmc, this is probably not currently an issue but is still good to
fix though.

Fixes: 3fc7eaef44db ("mmc: dw_mmc: Add external dma interface support")
Cc: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
Cc: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
Cc: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxx>
Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210810081644.19353-2-tony@xxxxxxxxxxx
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/mmc/host/dw_mmc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 8b5d542e20f3..7f90326b1be5 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -782,6 +782,7 @@ static int dw_mci_edmac_start_dma(struct dw_mci *host,
 	int ret = 0;
 
 	/* Set external dma config: burst size, burst width */
+	memset(&cfg, 0, sizeof(cfg));
 	cfg.dst_addr = host->phy_regs + fifo_offset;
 	cfg.src_addr = cfg.dst_addr;
 	cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-- 
2.30.2