linux-kernel - Re: [PATCH] hw_random: atmel-rng: fix data valid check

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Message-ID: <4FD619B9.9070802@atmel.com>
Date:	Mon, 11 Jun 2012 18:15:53 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Peter Korsgaard <jacmet@...site.dk>, <herbert@...dor.apana.org.au>
CC:	<jamie@...ieiles.com>, <linux-kernel@...r.kernel.org>,
	<GPontis@...com>, <stable@...r.kernel.org>
Subject: Re: [PATCH] hw_random: atmel-rng: fix data valid check

On 05/23/2012 03:00 PM, Nicolas Ferre :
> On 05/23/2012 02:31 PM, Peter Korsgaard :
>> Brown paper bag: Data valid is LSB of the ISR (status register), and NOT
>> of ODATA (current random data word)!
>>
>> With this, rngtest is a lot happier. Before:
>>
>> rngtest 3
>> Copyright (c) 2004 by Henrique de Moraes Holschuh
>> This is free software; see the source for copying conditions.  There is NO warr.
>>
>> rngtest: starting FIPS tests...
>> rngtest: bits received from input: 20000032
>> rngtest: FIPS 140-2 successes: 3
>> rngtest: FIPS 140-2 failures: 997
>> rngtest: FIPS 140-2(2001-10-10) Monobit: 604
>> rngtest: FIPS 140-2(2001-10-10) Poker: 996
>> rngtest: FIPS 140-2(2001-10-10) Runs: 36
>> rngtest: FIPS 140-2(2001-10-10) Long run: 0
>> rngtest: FIPS 140-2(2001-10-10) Continuous run: 117
>> rngtest: input channel speed: (min=622.371; avg=23682.481; max=28224.350)Kibitss
>> rngtest: FIPS tests speed: (min=12.361; avg=12.718; max=12.861)Mibits/s
>> rngtest: Program run time: 2331696 microsecondsx
>>
>> After:
>> rngtest 3
>> Copyright (c) 2004 by Henrique de Moraes Holschuh
>> This is free software; see the source for copying conditions.  There is NO warr.
>>
>> rngtest: starting FIPS tests...
>> rngtest: bits received from input: 20000032
>> rngtest: FIPS 140-2 successes: 999
>> rngtest: FIPS 140-2 failures: 1
>> rngtest: FIPS 140-2(2001-10-10) Monobit: 0
>> rngtest: FIPS 140-2(2001-10-10) Poker: 0
>> rngtest: FIPS 140-2(2001-10-10) Runs: 1
>> rngtest: FIPS 140-2(2001-10-10) Long run: 0
>> rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
>> rngtest: input channel speed: (min=777.363; avg=43588.270; max=47870.711)Kibitss
>> rngtest: FIPS tests speed: (min=11.943; avg=12.716; max=12.844)Mibits/s
>> rngtest: Program run time: 1955282 microseconds
>>
>> Cc: stable@...r.kernel.org
>> Signed-off-by: Peter Korsgaard <jacmet@...site.dk>
>> Reported-by: George Pontis <GPontis@...com>
> 
> Indeed, yes ;-)
> 
> Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>

Hi Herbert,

It seems that this patch did not make it in your tree before the "other
one" from Peter: in linus' tree: 121daad (hwrng: atmel-rng - fix race
condition leading to repeated bits).

So, do you want me to rebase this patch because it will not apply anymore?

Thanks for your help, best regards,

>> ---
>>  drivers/char/hw_random/atmel-rng.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c
>> index f518b99..d7ab920 100644
>> --- a/drivers/char/hw_random/atmel-rng.c
>> +++ b/drivers/char/hw_random/atmel-rng.c
>> @@ -34,7 +34,7 @@ static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max,
>>  	u32 *data = buf;
>>  
>>  	/* data ready? */
>> -	if (readl(trng->base + TRNG_ODATA) & 1) {
>> +	if (readl(trng->base + TRNG_ISR) & 1) {
>>  		*data = readl(trng->base + TRNG_ODATA);
>>  		return 4;
>>  	} else
> 
> 


-- 
Nicolas Ferre
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