diff mbox

[v4,1/6] usb: musb: core: Handle Babble condition only in HOST mode

Message ID 1400506776-2816-2-git-send-email-george.cherian@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

George Cherian May 19, 2014, 1:39 p.m. UTC
BABBLE and RESET share the same interrupt. The interrupt
is considered to be RESET if MUSB is in peripheral mode and
as a BABBLE if MUSB is in HOST mode.

Handle babble condition iff MUSB is in HOST mode.

Signed-off-by: George Cherian <george.cherian@ti.com>
---
 drivers/usb/musb/musb_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bin Liu May 19, 2014, 3:54 p.m. UTC | #1
Hi,

On Mon, May 19, 2014 at 8:39 AM, George Cherian <george.cherian@ti.com> wrote:
> BABBLE and RESET share the same interrupt. The interrupt
> is considered to be RESET if MUSB is in peripheral mode and
> as a BABBLE if MUSB is in HOST mode.
>
> Handle babble condition iff MUSB is in HOST mode.
>
> Signed-off-by: George Cherian <george.cherian@ti.com>
> ---
>  drivers/usb/musb/musb_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
> index 61da471..eff3c5c 100644
> --- a/drivers/usb/musb/musb_core.c
> +++ b/drivers/usb/musb/musb_core.c
> @@ -849,7 +849,7 @@ b_host:
>         }
>
>         /* handle babble condition */
> -       if (int_usb & MUSB_INTR_BABBLE)
> +       if (int_usb & MUSB_INTR_BABBLE && is_host_active(musb))
>                 schedule_work(&musb->recover_work);

I guess my following comments are for Daniel's patch as while which
initially added the babble work.

Should this if statement be merged into the previous 'if(int_usb &
MUSB_INTR_RESET)' one, which handles the same interrupt and already
handles host and device mode respectively.

Regards,
-Bin.

>
>  #if 0
> --
> 1.8.3.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-usb" 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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George Cherian May 20, 2014, 4:32 a.m. UTC | #2
Hi Bin,
On 5/19/2014 9:24 PM, Bin Liu wrote:
> Hi,
>
> On Mon, May 19, 2014 at 8:39 AM, George Cherian <george.cherian@ti.com> wrote:
>> BABBLE and RESET share the same interrupt. The interrupt
>> is considered to be RESET if MUSB is in peripheral mode and
>> as a BABBLE if MUSB is in HOST mode.
>>
>> Handle babble condition iff MUSB is in HOST mode.
>>
>> Signed-off-by: George Cherian <george.cherian@ti.com>
>> ---
>>   drivers/usb/musb/musb_core.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
>> index 61da471..eff3c5c 100644
>> --- a/drivers/usb/musb/musb_core.c
>> +++ b/drivers/usb/musb/musb_core.c
>> @@ -849,7 +849,7 @@ b_host:
>>          }
>>
>>          /* handle babble condition */
>> -       if (int_usb & MUSB_INTR_BABBLE)
>> +       if (int_usb & MUSB_INTR_BABBLE && is_host_active(musb))
>>                  schedule_work(&musb->recover_work);
> I guess my following comments are for Daniel's patch as while which
> initially added the babble work.
>
> Should this if statement be merged into the previous 'if(int_usb &
> MUSB_INTR_RESET)' one, which handles the same interrupt and already
> handles host and device mode respectively.

Initially I too had the babble handling as part of  'if(int_usb & 
MUSB_INTR_RESET)'
one. But during my tests I hit a corner case where in we hit a BABBLE 
condition
on disconnect. In such case the babble interrupt can be handled only if 
we have a seperate
check, else its considered as a BUS RESET.

When all devices are disconnected  MUSB_DEVCTL_HM = 0 and the code 
always enter the
else path. In this path it treats the BABBLE as a BUS RESET.

> Regards,
> -Bin.
>
>>   #if 0
>> --
>> 1.8.3.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Bin Liu May 22, 2014, 8:42 p.m. UTC | #3
Hi George,

On Mon, May 19, 2014 at 11:32 PM, George Cherian <george.cherian@ti.com> wrote:
> Hi Bin,
>
> On 5/19/2014 9:24 PM, Bin Liu wrote:
>>
>> Hi,
>>
>> On Mon, May 19, 2014 at 8:39 AM, George Cherian <george.cherian@ti.com>
>> wrote:
>>>
>>> BABBLE and RESET share the same interrupt. The interrupt
>>> is considered to be RESET if MUSB is in peripheral mode and
>>> as a BABBLE if MUSB is in HOST mode.
>>>
>>> Handle babble condition iff MUSB is in HOST mode.
>>>
>>> Signed-off-by: George Cherian <george.cherian@ti.com>
>>> ---
>>>   drivers/usb/musb/musb_core.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
>>> index 61da471..eff3c5c 100644
>>> --- a/drivers/usb/musb/musb_core.c
>>> +++ b/drivers/usb/musb/musb_core.c
>>> @@ -849,7 +849,7 @@ b_host:
>>>          }
>>>
>>>          /* handle babble condition */
>>> -       if (int_usb & MUSB_INTR_BABBLE)
>>> +       if (int_usb & MUSB_INTR_BABBLE && is_host_active(musb))
>>>                  schedule_work(&musb->recover_work);
>>
>> I guess my following comments are for Daniel's patch as while which
>> initially added the babble work.
>>
>> Should this if statement be merged into the previous 'if(int_usb &
>> MUSB_INTR_RESET)' one, which handles the same interrupt and already
>> handles host and device mode respectively.
>
>
> Initially I too had the babble handling as part of  'if(int_usb &
> MUSB_INTR_RESET)'
> one. But during my tests I hit a corner case where in we hit a BABBLE
> condition
> on disconnect. In such case the babble interrupt can be handled only if we
> have a seperate
> check, else its considered as a BUS RESET.
>
> When all devices are disconnected  MUSB_DEVCTL_HM = 0 and the code always
> enter the
> else path. In this path it treats the BABBLE as a BUS RESET.

The code flow is a bit confusing, two if() handle the same interrupt.
The second one implied using 'handled = IRQ_HANDLED;' from the first
one.
Also does the switch() in else{} in the first if() cause any side effect?

Since this babble handing is AM335x specific, how about handle it in
dsps_interrupt() in musb_dsps.c, which already has an entry for babble
interrupt? TI 3.2 kernel does this way.

Regards,
-Bin.

>
>
>> Regards,
>> -Bin.
>>
>>>   #if 0
>>> --
>>> 1.8.3.1
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
>
> --
> -George
>
--
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George Cherian May 26, 2014, 8:46 a.m. UTC | #4
On 5/23/2014 2:12 AM, Bin Liu wrote:
> Hi George,
>
> On Mon, May 19, 2014 at 11:32 PM, George Cherian <george.cherian@ti.com> wrote:
>> Hi Bin,
>>
>> On 5/19/2014 9:24 PM, Bin Liu wrote:
>>> Hi,
>>>
>>> On Mon, May 19, 2014 at 8:39 AM, George Cherian <george.cherian@ti.com>
>>> wrote:
>>>> BABBLE and RESET share the same interrupt. The interrupt
>>>> is considered to be RESET if MUSB is in peripheral mode and
>>>> as a BABBLE if MUSB is in HOST mode.
>>>>
>>>> Handle babble condition iff MUSB is in HOST mode.
>>>>
>>>> Signed-off-by: George Cherian <george.cherian@ti.com>
>>>> ---
>>>>    drivers/usb/musb/musb_core.c | 2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
>>>> index 61da471..eff3c5c 100644
>>>> --- a/drivers/usb/musb/musb_core.c
>>>> +++ b/drivers/usb/musb/musb_core.c
>>>> @@ -849,7 +849,7 @@ b_host:
>>>>           }
>>>>
>>>>           /* handle babble condition */
>>>> -       if (int_usb & MUSB_INTR_BABBLE)
>>>> +       if (int_usb & MUSB_INTR_BABBLE && is_host_active(musb))
>>>>                   schedule_work(&musb->recover_work);
>>> I guess my following comments are for Daniel's patch as while which
>>> initially added the babble work.
>>>
>>> Should this if statement be merged into the previous 'if(int_usb &
>>> MUSB_INTR_RESET)' one, which handles the same interrupt and already
>>> handles host and device mode respectively.
>>
>> Initially I too had the babble handling as part of  'if(int_usb &
>> MUSB_INTR_RESET)'
>> one. But during my tests I hit a corner case where in we hit a BABBLE
>> condition
>> on disconnect. In such case the babble interrupt can be handled only if we
>> have a seperate
>> check, else its considered as a BUS RESET.
>>
>> When all devices are disconnected  MUSB_DEVCTL_HM = 0 and the code always
>> enter the
>> else path. In this path it treats the BABBLE as a BUS RESET.
> The code flow is a bit confusing, two if() handle the same interrupt.
> The second one implied using 'handled = IRQ_HANDLED;' from the first
> one.
> Also does the switch() in else{} in the first if() cause any side effect?
No it doesn't.
> Since this babble handing is AM335x specific, how about handle it in
> dsps_interrupt() in musb_dsps.c, which already has an entry for babble
> interrupt? TI 3.2 kernel does this way.
That the reason we have platform specific callbacks added  from the main 
interrupt handler.
> Regards,
> -Bin.
>
>>
>>> Regards,
>>> -Bin.
>>>
>>>>    #if 0
>>>> --
>>>> 1.8.3.1
>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>> --
>> -George
>>
diff mbox

Patch

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 61da471..eff3c5c 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -849,7 +849,7 @@  b_host:
 	}
 
 	/* handle babble condition */
-	if (int_usb & MUSB_INTR_BABBLE)
+	if (int_usb & MUSB_INTR_BABBLE && is_host_active(musb))
 		schedule_work(&musb->recover_work);
 
 #if 0