[PATCH v4] mmc: dw_mmc: Fix the DTO/CTO timeout overflow calculation for 32-bit systems

[Evgeniy Didin]

In commit 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation") and
commit 4c2357f57dd5 ("mmc: dw_mmc: Fix the CTO timeout calculation") 
have been made changes which cause multiply overflow for 32-bit systems.
The broken timeout calculations leads to unexpected ETIMEDOUT errors and 
causes stacktrace splat (such as below) during normal data exchange 
with SD-card.

| Running :  4M-check-reassembly-tcp-cmykw2-rotatew2.out -v0 -w1
| -  Info: Finished target initialization.
| mmcblk0: error -110 transferring data, sector 320544, nr 2048, cmd response
|  0x900, card status 0x0

DIV_ROUND_UP_ULL helps to escape usage of __udivdi3() from libgcc and so
code gets compiled on all 32-bit platforms as opposed to usage
of DIV_ROUND_UP when we may only compile stuff on a very few arches.

Lets cast this multiply to u64 type which prevents overflow.

Tested-by: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx>
Reported-by: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx> # ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files
Fixes: 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation")
Fixes: 4c2357f57dd5 ("mmc: dw_mmc: Fix the CTO timeout calculation")

Signed-off-by: Evgeniy Didin <Evgeniy.Didin@xxxxxxxxxxxx>

CC: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
CC: Eugeniy Paltsev <paltsev@xxxxxxxxxxxx>
CC: Douglas Anderson <dianders@xxxxxxxxxxxx>
CC: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
CC: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
CC: Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx>
CC: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
CC: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx>
CC: linux-kernel@xxxxxxxxxxxxxxx
CC: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> 
---
Changes since v3:
-Switch DIV_ROUND_UP macro to DIV_ROUND_UP_ULL
-Make one patch from two patches
-Modify commit message

Changes sinve v2:
-add fix for cto_ms

Changes since v1:
-uint64_t switched to u64

 drivers/mmc/host/dw_mmc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 0aa39975f33b..cba534d4c81b 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -409,7 +409,9 @@ static inline void dw_mci_set_cto(struct dw_mci *host)
 	cto_div = (mci_readl(host, CLKDIV) & 0xff) * 2;
 	if (cto_div == 0)
 		cto_div = 1;
-	cto_ms = DIV_ROUND_UP(MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz);
+
+	cto_ms = DIV_ROUND_UP_ULL((u64)MSEC_PER_SEC * cto_clks * cto_div,
+				  host->bus_hz);
 
 	/* add a bit spare time */
 	cto_ms += 10;
@@ -1944,8 +1946,9 @@ static void dw_mci_set_drto(struct dw_mci *host)
 	drto_div = (mci_readl(host, CLKDIV) & 0xff) * 2;
 	if (drto_div == 0)
 		drto_div = 1;
-	drto_ms = DIV_ROUND_UP(MSEC_PER_SEC * drto_clks * drto_div,
-			       host->bus_hz);
+
+	drto_ms = DIV_ROUND_UP_ULL((u64)MSEC_PER_SEC * drto_clks * drto_div,
+				   host->bus_hz);
 
 	/* add a bit spare time */
 	drto_ms += 10;
-- 
2.11.0