[PATCH] mmc: dwmmc: only clear handled interrupts

[John Keeping <john@metanate.com>]

Unconditionally clearing DTO when RXDR is set leads to spurious timeouts
in FIFO mode transfers if events occur in the following order:

	mask = dwmci_readl(host, DWMCI_RINTSTS);

	// Hardware asserts DWMCI_INTMSK_DTO here

	dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_DTO);

	if (mask & DWMCI_INTMSK_DTO) {
		// Unreachable as DTO is cleared without being handled!
		return 0;
	}

Only clear interrupts that we have seen and are handling so that DTO is
not missed.

Signed-off-by: John Keeping <john@metanate.com>
---
 drivers/mmc/dw_mmc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
index 4232c5eb8c..5085a3b491 100644
--- a/drivers/mmc/dw_mmc.c
+++ b/drivers/mmc/dw_mmc.c
@@ -168,7 +168,8 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)
 			if (data->flags == MMC_DATA_READ &&
 			    (mask & (DWMCI_INTMSK_RXDR | DWMCI_INTMSK_DTO))) {
 				dwmci_writel(host, DWMCI_RINTSTS,
-					     DWMCI_INTMSK_RXDR | DWMCI_INTMSK_DTO);
+					     mask & (DWMCI_INTMSK_RXDR |
+						     DWMCI_INTMSK_DTO));
 				while (size) {
 					ret = dwmci_fifo_ready(host,
 							DWMCI_FIFO_EMPTY,
-- 
2.37.3