Re: [PATCH 1/2 v3] mmc: dw_mmc: Fix the DTO timeout overflow calculation for 32-bit systems

From: Shawn Lin
Date: Mon Feb 26 2018 - 20:14:55 EST



Tested-by: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx>
Fixes: ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files

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: linux-kernel@xxxxxxxxxxxxxxx
CC: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # 9d9491a7da2a mmc: dw_mmc: Fix the DTO timeout calculation

As I said, the correct tag may be:

Reported-by: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx> # ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files
Tested-by: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx>
Fixes: 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Evgeniy Didin <Evgeniy.Didin@xxxxxxxxxxxx>
...
...


---
Nothing changed since v2.
drivers/mmc/host/dw_mmc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)


- drto_ms = DIV_ROUND_UP(MSEC_PER_SEC * drto_clks * drto_div,
+
+ drto_ms = DIV_ROUND_UP((u64)MSEC_PER_SEC * drto_clks * drto_div,
host->bus_hz);

Hmm?

#define DIV_ROUND_DOWN_ULL(ll, d) \
({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })

#define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d))


It uses intermediate unsigned long long _tmp for your "multiply", namely
MSEC_PER_SEC * drto_clks * drto_div, which could solves the problem.
So I don't see why DIV_ROUND_UP_ULL can't work for you?


/* add a bit spare time */