[PATCH] mmc: mmci: stm32: fix max busy timeout calculation

[Yann Gautier]

From: Christophe Kerello <christophe.kerello@xxxxxxxxxxx>

The way that the timeout is currently calculated could lead to a u64
timeout value in mmci_start_command(). This value is then cast in a u32
register that leads to mmc erase failed issue with some SD cards.

Fixes: 8266c585f489 ("mmc: mmci: add hardware busy timeout feature")
Signed-off-by: Yann Gautier <yann.gautier@xxxxxxxxxxx>
Signed-off-by: Christophe Kerello <christophe.kerello@xxxxxxxxxxx>
---
 drivers/mmc/host/mmci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index f2b2e8b0574e8..696cbef3ff7de 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1735,7 +1735,8 @@ static void mmci_set_max_busy_timeout(struct mmc_host *mmc)
 		return;
 
 	if (host->variant->busy_timeout && mmc->actual_clock)
-		max_busy_timeout = ~0UL / (mmc->actual_clock / MSEC_PER_SEC);
+		max_busy_timeout = U32_MAX / DIV_ROUND_UP(mmc->actual_clock,
+							  MSEC_PER_SEC);
 
 	mmc->max_busy_timeout = max_busy_timeout;
 }
-- 
2.25.1