diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 6b39126fbf06c..a1df6d4e9e86e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1222,6 +1222,7 @@ static int sdhci_external_dma_setup(struct sdhci_host *host,
 	if (!host->mapbase)
 		return -EINVAL;
 
+	memset(&cfg, 0, sizeof(cfg));
 	cfg.src_addr = host->mapbase + SDHCI_BUFFER;
 	cfg.dst_addr = host->mapbase + SDHCI_BUFFER;
 	cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;