diff mbox

[V2] sdhci: only reprogram retuning timer when flag is set

Message ID 1384163395-27038-1-git-send-email-arend@broadcom.com (mailing list archive)
State New, archived
Headers show

Commit Message

Arend van Spriel Nov. 11, 2013, 9:49 a.m. UTC
When the host->tuning_count is zero it means that the
retuning is disabled. This is checked on the first
run of sdhci_execute_tuning() by the if statement below:

	if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count &&
	    (host->tuning_mode == SDHCI_TUNING_MODE_1)) {

So only when tuning_count is non-zero it will set the host
flag SDHCI_USING_RETUNING_TIMER. The else statement is only
for re-programming the timer, which means that flag must be
set. Because that is not checked the else statement is executed
in the first run when tuning_count is zero.

This was seen on a host controller which indicated
SDHCI_TUNING_MODE_1 (0) and tuning_count being zero. Suspect
that (one of) these registers is not properly set.

Signed-off-by: Arend van Spriel <arend@broadcom.com>
---
This patch applies to the mmc-next branch.

V2:
- add more explanation to the commit message
- check host flag SDHCI_USING_RETUNING_TIMER
---
 drivers/mmc/host/sdhci.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Aaron Lu Nov. 12, 2013, 6:49 a.m. UTC | #1
On 11/11/2013 05:49 PM, Arend van Spriel wrote:
> When the host->tuning_count is zero it means that the
> retuning is disabled. This is checked on the first
> run of sdhci_execute_tuning() by the if statement below:
> 
> 	if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count &&
> 	    (host->tuning_mode == SDHCI_TUNING_MODE_1)) {
> 
> So only when tuning_count is non-zero it will set the host
> flag SDHCI_USING_RETUNING_TIMER. The else statement is only
> for re-programming the timer, which means that flag must be
> set. Because that is not checked the else statement is executed
> in the first run when tuning_count is zero.
> 
> This was seen on a host controller which indicated
> SDHCI_TUNING_MODE_1 (0) and tuning_count being zero. Suspect
> that (one of) these registers is not properly set.
> 
> Signed-off-by: Arend van Spriel <arend@broadcom.com>

Reviewed-by: Aaron Lu <aaron.lu@intel.com>

-Aaron

> ---
> This patch applies to the mmc-next branch.
> 
> V2:
> - add more explanation to the commit message
> - check host flag SDHCI_USING_RETUNING_TIMER
> ---
>  drivers/mmc/host/sdhci.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index bd8a098..5974599 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2014,7 +2014,7 @@ out:
>  			host->tuning_count * HZ);
>  		/* Tuning mode 1 limits the maximum data length to 4MB */
>  		mmc->max_blk_count = (4 * 1024 * 1024) / mmc->max_blk_size;
> -	} else {
> +	} else if (host->flags & SDHCI_USING_RETUNING_TIMER) {
>  		host->flags &= ~SDHCI_NEEDS_RETUNING;
>  		/* Reload the new initial value for timer */
>  		if (host->tuning_mode == SDHCI_TUNING_MODE_1)
> 

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Dong Aisheng Nov. 13, 2013, 5:02 a.m. UTC | #2
Hi Arend,

On Mon, Nov 11, 2013 at 5:49 PM, Arend van Spriel <arend@broadcom.com> wrote:
> When the host->tuning_count is zero it means that the
> retuning is disabled. This is checked on the first
> run of sdhci_execute_tuning() by the if statement below:
>
>         if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count &&
>             (host->tuning_mode == SDHCI_TUNING_MODE_1)) {
>
> So only when tuning_count is non-zero it will set the host
> flag SDHCI_USING_RETUNING_TIMER. The else statement is only
> for re-programming the timer, which means that flag must be
> set. Because that is not checked the else statement is executed
> in the first run when tuning_count is zero.
>
> This was seen on a host controller which indicated
> SDHCI_TUNING_MODE_1 (0) and tuning_count being zero. Suspect
> that (one of) these registers is not properly set.
>
> Signed-off-by: Arend van Spriel <arend@broadcom.com>
> ---
> This patch applies to the mmc-next branch.
>
> V2:
> - add more explanation to the commit message
> - check host flag SDHCI_USING_RETUNING_TIMER
> ---
>  drivers/mmc/host/sdhci.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index bd8a098..5974599 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2014,7 +2014,7 @@ out:
>                         host->tuning_count * HZ);
>                 /* Tuning mode 1 limits the maximum data length to 4MB */
>                 mmc->max_blk_count = (4 * 1024 * 1024) / mmc->max_blk_size;
> -       } else {
> +       } else if (host->flags & SDHCI_USING_RETUNING_TIMER) {
>                 host->flags &= ~SDHCI_NEEDS_RETUNING;
>                 /* Reload the new initial value for timer */
>                 if (host->tuning_mode == SDHCI_TUNING_MODE_1)

I wonder if we could also remove this line?
It looks to me it's not neccesary to check the tuning_mode again since
we already check the flag
above and SDHCI_TUNING_MODE_1 seems like the prerequisite of
SDHCI_USING_RETUNING_TIMER.

Regards
Dong Aisheng

> --
> 1.7.10.4
>
>
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Arend van Spriel Nov. 13, 2013, 10:21 a.m. UTC | #3
On 11/13/2013 06:02 AM, Dong Aisheng wrote:
> Hi Arend,
>
> On Mon, Nov 11, 2013 at 5:49 PM, Arend van Spriel <arend@broadcom.com> wrote:
>> When the host->tuning_count is zero it means that the
>> retuning is disabled. This is checked on the first
>> run of sdhci_execute_tuning() by the if statement below:
>>
>>          if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count &&
>>              (host->tuning_mode == SDHCI_TUNING_MODE_1)) {
>>
>> So only when tuning_count is non-zero it will set the host
>> flag SDHCI_USING_RETUNING_TIMER. The else statement is only
>> for re-programming the timer, which means that flag must be
>> set. Because that is not checked the else statement is executed
>> in the first run when tuning_count is zero.
>>
>> This was seen on a host controller which indicated
>> SDHCI_TUNING_MODE_1 (0) and tuning_count being zero. Suspect
>> that (one of) these registers is not properly set.
>>
>> Signed-off-by: Arend van Spriel <arend@broadcom.com>
>> ---
>> This patch applies to the mmc-next branch.
>>
>> V2:
>> - add more explanation to the commit message
>> - check host flag SDHCI_USING_RETUNING_TIMER
>> ---
>>   drivers/mmc/host/sdhci.c |    2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index bd8a098..5974599 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -2014,7 +2014,7 @@ out:
>>                          host->tuning_count * HZ);
>>                  /* Tuning mode 1 limits the maximum data length to 4MB */
>>                  mmc->max_blk_count = (4 * 1024 * 1024) / mmc->max_blk_size;
>> -       } else {
>> +       } else if (host->flags & SDHCI_USING_RETUNING_TIMER) {
>>                  host->flags &= ~SDHCI_NEEDS_RETUNING;
>>                  /* Reload the new initial value for timer */
>>                  if (host->tuning_mode == SDHCI_TUNING_MODE_1)
>
> I wonder if we could also remove this line?
> It looks to me it's not neccesary to check the tuning_mode again since
> we already check the flag
> above and SDHCI_TUNING_MODE_1 seems like the prerequisite of
> SDHCI_USING_RETUNING_TIMER.

According the spec the other tuning modes also can use retuning timer. 
Currently, the mmc stack in upstream linux only supports tuning mode 1. 
When adding the other modes this if statement will probably go.

Regards,
Arend

> Regards
> Dong Aisheng
>
>> --
>> 1.7.10.4
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>


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Dong Aisheng Nov. 13, 2013, 11:12 a.m. UTC | #4
Hi Arend,

On Wed, Nov 13, 2013 at 6:21 PM, Arend van Spriel <arend@broadcom.com> wrote:
> On 11/13/2013 06:02 AM, Dong Aisheng wrote:
>>
>> Hi Arend,
>>
>> On Mon, Nov 11, 2013 at 5:49 PM, Arend van Spriel <arend@broadcom.com>
>> wrote:
>>>
>>> When the host->tuning_count is zero it means that the
>>> retuning is disabled. This is checked on the first
>>> run of sdhci_execute_tuning() by the if statement below:
>>>
>>>          if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count
>>> &&
>>>              (host->tuning_mode == SDHCI_TUNING_MODE_1)) {
>>>
>>> So only when tuning_count is non-zero it will set the host
>>> flag SDHCI_USING_RETUNING_TIMER. The else statement is only
>>> for re-programming the timer, which means that flag must be
>>> set. Because that is not checked the else statement is executed
>>> in the first run when tuning_count is zero.
>>>
>>> This was seen on a host controller which indicated
>>> SDHCI_TUNING_MODE_1 (0) and tuning_count being zero. Suspect
>>> that (one of) these registers is not properly set.
>>>
>>> Signed-off-by: Arend van Spriel <arend@broadcom.com>
>>> ---
>>> This patch applies to the mmc-next branch.
>>>
>>> V2:
>>> - add more explanation to the commit message
>>> - check host flag SDHCI_USING_RETUNING_TIMER
>>> ---
>>>   drivers/mmc/host/sdhci.c |    2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index bd8a098..5974599 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -2014,7 +2014,7 @@ out:
>>>                          host->tuning_count * HZ);
>>>                  /* Tuning mode 1 limits the maximum data length to 4MB
>>> */
>>>                  mmc->max_blk_count = (4 * 1024 * 1024) /
>>> mmc->max_blk_size;
>>> -       } else {
>>> +       } else if (host->flags & SDHCI_USING_RETUNING_TIMER) {
>>>                  host->flags &= ~SDHCI_NEEDS_RETUNING;
>>>                  /* Reload the new initial value for timer */
>>>                  if (host->tuning_mode == SDHCI_TUNING_MODE_1)
>>
>>
>> I wonder if we could also remove this line?
>> It looks to me it's not neccesary to check the tuning_mode again since
>> we already check the flag
>> above and SDHCI_TUNING_MODE_1 seems like the prerequisite of
>> SDHCI_USING_RETUNING_TIMER.
>
>
> According the spec the other tuning modes also can use retuning timer.
> Currently, the mmc stack in upstream linux only supports tuning mode 1. When
> adding the other modes this if statement will probably go.
>

For currently code, it looks like also not necessary to check it since
SDHCI_USING_RETUNING_TIMER will only be set when tunning_mode is
SDHCI_TUNING_MODE_1.
And SDHCI_TUNING_MODE_1 just indicates the tuning mode while the flag
SDHCI_USING_RETUNING_TIMER represents the retuning timer implementation.
So check the flag to invoke the timer seems make more sense to me.
do you agree?

Regards
Dong Aisheng

> Regards,
> Arend
>
>
>> Regards
>> Dong Aisheng
>>
>>> --
>>> 1.7.10.4
>>>
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>
>
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Arend van Spriel Nov. 13, 2013, 11:18 a.m. UTC | #5
On 11/13/2013 12:12 PM, Dong Aisheng wrote:
> Hi Arend,
>
> On Wed, Nov 13, 2013 at 6:21 PM, Arend van Spriel <arend@broadcom.com> wrote:
>> On 11/13/2013 06:02 AM, Dong Aisheng wrote:
>>>
>>> Hi Arend,
>>>
>>> On Mon, Nov 11, 2013 at 5:49 PM, Arend van Spriel <arend@broadcom.com>
>>> wrote:
>>>>
>>>> When the host->tuning_count is zero it means that the
>>>> retuning is disabled. This is checked on the first
>>>> run of sdhci_execute_tuning() by the if statement below:
>>>>
>>>>           if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count
>>>> &&
>>>>               (host->tuning_mode == SDHCI_TUNING_MODE_1)) {
>>>>
>>>> So only when tuning_count is non-zero it will set the host
>>>> flag SDHCI_USING_RETUNING_TIMER. The else statement is only
>>>> for re-programming the timer, which means that flag must be
>>>> set. Because that is not checked the else statement is executed
>>>> in the first run when tuning_count is zero.
>>>>
>>>> This was seen on a host controller which indicated
>>>> SDHCI_TUNING_MODE_1 (0) and tuning_count being zero. Suspect
>>>> that (one of) these registers is not properly set.
>>>>
>>>> Signed-off-by: Arend van Spriel <arend@broadcom.com>
>>>> ---
>>>> This patch applies to the mmc-next branch.
>>>>
>>>> V2:
>>>> - add more explanation to the commit message
>>>> - check host flag SDHCI_USING_RETUNING_TIMER
>>>> ---
>>>>    drivers/mmc/host/sdhci.c |    2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>> index bd8a098..5974599 100644
>>>> --- a/drivers/mmc/host/sdhci.c
>>>> +++ b/drivers/mmc/host/sdhci.c
>>>> @@ -2014,7 +2014,7 @@ out:
>>>>                           host->tuning_count * HZ);
>>>>                   /* Tuning mode 1 limits the maximum data length to 4MB
>>>> */
>>>>                   mmc->max_blk_count = (4 * 1024 * 1024) /
>>>> mmc->max_blk_size;
>>>> -       } else {
>>>> +       } else if (host->flags & SDHCI_USING_RETUNING_TIMER) {
>>>>                   host->flags &= ~SDHCI_NEEDS_RETUNING;
>>>>                   /* Reload the new initial value for timer */
>>>>                   if (host->tuning_mode == SDHCI_TUNING_MODE_1)
>>>
>>>
>>> I wonder if we could also remove this line?
>>> It looks to me it's not neccesary to check the tuning_mode again since
>>> we already check the flag
>>> above and SDHCI_TUNING_MODE_1 seems like the prerequisite of
>>> SDHCI_USING_RETUNING_TIMER.
>>
>>
>> According the spec the other tuning modes also can use retuning timer.
>> Currently, the mmc stack in upstream linux only supports tuning mode 1. When
>> adding the other modes this if statement will probably go.
>>
>
> For currently code, it looks like also not necessary to check it since
> SDHCI_USING_RETUNING_TIMER will only be set when tunning_mode is
> SDHCI_TUNING_MODE_1.
> And SDHCI_TUNING_MODE_1 just indicates the tuning mode while the flag
> SDHCI_USING_RETUNING_TIMER represents the retuning timer implementation.
> So check the flag to invoke the timer seems make more sense to me.
> do you agree?

The flag SDHCI_USING_RETUNING_TIMER is only set after the initial tuning 
run so in the if-statement. So currently in the else-statement the fact 
that SDHCI_USING_RETUNING_TIMER is set implies SDHCI_TUNING_MODE_1.

Regards,
Arend

> Regards
> Dong Aisheng
>
>> Regards,
>> Arend
>>
>>
>>> Regards
>>> Dong Aisheng
>>>
>>>> --
>>>> 1.7.10.4
>>>>
>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>>
>>
>>
>


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diff mbox

Patch

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index bd8a098..5974599 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2014,7 +2014,7 @@  out:
 			host->tuning_count * HZ);
 		/* Tuning mode 1 limits the maximum data length to 4MB */
 		mmc->max_blk_count = (4 * 1024 * 1024) / mmc->max_blk_size;
-	} else {
+	} else if (host->flags & SDHCI_USING_RETUNING_TIMER) {
 		host->flags &= ~SDHCI_NEEDS_RETUNING;
 		/* Reload the new initial value for timer */
 		if (host->tuning_mode == SDHCI_TUNING_MODE_1)