On 11/08/2013 05:10 PM, Arend van Spriel wrote:
> On 11/08/2013 07:50 AM, Aaron Lu wrote:
>> On 11/07/2013 06:59 PM, Arend van Spriel wrote:
>>> When the host->tuning_count is zero it means that the
>>
>> If the tuning_count is zero, then the retuning timer shouldn't be
>> started in the first place and not possible to run code there. Or is the
>> tuning_count dynamically changed?
>
> Actually, the sdhci_execute_tuning() must run once to do the initial
> tuning procedure. This is mandatory for SDR104. However, *re*tuning is
> not and a zero tuning_count disables it.
So the host in question doesn't need do retuning while in SDR104 mode?
It seems your host's retuning mode is mode_1.
>
> The function is executed initially. The 'if' statement above the patched
> 'else' statement is actually responsible for programming the retuning
> timer for the first time. However, it requires tuning_count to be
> non-zero. The 'else' statement is actually for reloading the retuning
> timer, which is not the case. Adding the non-zero check assures the
> retuning timer is never started.
OK, I see.
The SDHCI_USING_RETUNING_TIMER flag is supposed to mean if the host is
currently using retuning timer to do retuning, it could also be used to
decide if retuning timer needs be re-programmed.
Anyway, a host in retuning mode 1 does not have tuning_count set seems a
little odd to me...
Thanks,
Aaron
>
> I guess the fact that this needs explaining indicates that the commit
> message should be updated. I will send a V2 for this.
>
> Regards,
> Arend
>
>> Thanks,
>> Aaron
>>
>>> retuning is disabled. Doing a mod_timer() with a zero
>>> tuning_count does something else.
>>>
>>> Signed-off-by: Arend van Spriel <arend@xxxxxxxxxxxx>
>>> ---
>>> drivers/mmc/host/sdhci.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index 7a7fb4f..9803e7a 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -2007,7 +2007,8 @@ out:
>>> } else {
>>> host->flags &= ~SDHCI_NEEDS_RETUNING;
>>> /* Reload the new initial value for timer */
>>> - if (host->tuning_mode == SDHCI_TUNING_MODE_1)
>>> + if (host->tuning_count &&
>>> + host->tuning_mode == SDHCI_TUNING_MODE_1)
>>> mod_timer(&host->tuning_timer, jiffies +
>>> host->tuning_count * HZ);
>>> }
>>>
>>
>>
>
>
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