mmc: mmci: stm32: fix max busy timeout calculation

Christophe Kerello · fourmone · commit d33b43a4dcc4 · 2023-06-16T12:05:22.000+02:00
The way that the timeout is currently calculated could lead to a u64 timeout value. this value is then cast in a u32 register that leads to mmc erase failed issue with some SD cards. Change-Id: Ibe2682ba42e878c30b61471672800f5fc04ce87c Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com> Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/linux-stm32/+/311057 Tested-by: Eric FOURMONT <eric.fourmont-ext@st.com> Reviewed-by: Eric FOURMONT <eric.fourmont-ext@st.com> Domain-Review: Eric FOURMONT <eric.fourmont-ext@st.com>
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
@@ -1746,7 +1746,8 @@ 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;
 }

Original file line number	Diff line number	Diff line change
`@@ -1746,7 +1746,8 @@ static void mmci_set_max_busy_timeout(struct mmc_host *mmc)`
`1746`	`1746`	`return;`
`1747`	`1747`
`1748`	`1748`	`if (host->variant->busy_timeout && mmc->actual_clock)`
`1749`		`- max_busy_timeout = ~0UL / (mmc->actual_clock / MSEC_PER_SEC);`
	`1749`	`+ max_busy_timeout = U32_MAX / DIV_ROUND_UP(mmc->actual_clock,`
	`1750`	`+ MSEC_PER_SEC);`
`1750`	`1751`
`1751`	`1752`	`mmc->max_busy_timeout = max_busy_timeout;`
`1752`	`1753`	`}`