[U-Boot] EXT: Re: [PATCH 13/13] bootcount: i2c: Delay after writing

[Ray, Ian (GE Healthcare)]

> On 13 Mar 2019, at 15.42, Stefano Babic <sbabic at denx.de> wrote:
> 
> On 13/03/19 14:01, Heiko Schocher wrote:
>> Hello Stefano,
>> 
>> Am 13.03.2019 um 11:04 schrieb Stefano Babic:
>>> Hi Ian,
>>> 
>>> On 31/01/19 15:21, Ian Ray wrote:
>>>> Since 2018.11, the pattern of bootcount load and store has changed such
>>>> that bootcount_inc() and bootcount_error() will load, increment, store,
>>>> and load *again*.  The second load exposes a timing problem whereby the
>>>> i2c read fails.  The root cause _seems_ to relate to performance of the
>>>> 24c08 EEPROM.  Insert a delay after writing to work around this.
>>>> 
>>>> Signed-off-by: Ian Ray <ian.ray at ge.com>
>>>> ---
>>>>   drivers/bootcount/bootcount_i2c.c | 4 ++++
>>>>   1 file changed, 4 insertions(+)
>>>> 
>>>> diff --git a/drivers/bootcount/bootcount_i2c.c
>>>> b/drivers/bootcount/bootcount_i2c.c
>>>> index ed22389..dd86426 100644
>>>> --- a/drivers/bootcount/bootcount_i2c.c
>>>> +++ b/drivers/bootcount/bootcount_i2c.c
>>>> @@ -64,6 +64,10 @@ void bootcount_store(ulong a)
>>>>               CONFIG_BOOTCOUNT_ALEN, buf, sizeof(buf));
>>>>       if (ret != 0)
>>>>           puts("Error writing bootcount\n");
>>>> +    else
>>>> +        /* Datasheet claims 2 ms typical write cycle time.
>>>> +         * This delay ensures that next read will succeed. */
>>>> +        mdelay(5);
>>>>   
>>> 
>>> I see, but this is device specific while bootcount_i2c should be
>>> device-unaware. I know this driver is used with PMIC where no delay is
>>> required. Heiko, is it ok to put a fix delay here or should be
>>> configurable ?
>> 
>> I would prefer here to make this timeout configurable, thinking
>> about boottime constraints.
>> 
> 
> Right, I see the same - Ian, I have applied the whole series with the
> exception of this one to u-boot-imx, next branch.
> 

Thank you!  I will look in to the configuration.


> Regards,
> Stefano
> 
> -- 
> =====================================================================
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
> =====================================================================