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

[Jaehoon Chung <jh80.chung@samsung.com>]

On 03/01/2018 02:57 PM, Jisheng Zhang wrote:
> On Wed, 28 Feb 2018 14:53:18 +0300 Evgeniy Didin wrote:
> 
>> 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.
> 
> Reviewed-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

Acked-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung

> 
>>
>> Tested-by: Vineet Gupta <Vineet.Gupta1@synopsys.com>
>> Reported-by: Vineet Gupta <Vineet.Gupta1@synopsys.com> # 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@synopsys.com>
>>
>> CC: Alexey Brodkin <abrodkin@synopsys.com>
>> CC: Eugeniy Paltsev <paltsev@synopsys.com>
>> CC: Douglas Anderson <dianders@chromium.org>
>> CC: Ulf Hansson <ulf.hansson@linaro.org>
>> CC: Andy Shevchenko <andy.shevchenko@gmail.com>
>> CC: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
>> CC: Shawn Lin <shawn.lin@rock-chips.com>
>> CC: Vineet Gupta <Vineet.Gupta1@synopsys.com>
>> CC: linux-kernel@vger.kernel.org
>> CC: linux-snps-arc@lists.infradead.org
>> Cc: <stable@vger.kernel.org> 
>> ---
>> 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;
> 
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