Re: [PATCH v2 2/4] usb: dwc2: Add binding for AHB burst

[John Youn <John.Youn-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>]

On 11/17/2016 7:35 AM, Stefan Wahren wrote:
> Hi John,
> 
> Am 17.11.2016 um 00:47 schrieb John Youn:
>> Add the "snps,ahb-burst" binding and read it in.
>>
>> This property controls which burst type to perform on the AHB bus as a
>> master in internal DMA mode. This overrides the legacy param value,
>> which we need to keep around for now since several platforms use it.
>>
>> Some platforms may see better or worse performance based on this
>> value. The HAPS platform is one example where all INCRx have worse
>> performance than INCR.
>>
>> Other platforms (such as the Canyonlands board) report that the default
>> value causes system hangs.
>>
>> Signed-off-by: John Youn <johnyoun-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
>> Cc: Christian Lamparter <chunkeey-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
>> ---
>>  Documentation/devicetree/bindings/usb/dwc2.txt |  2 +
>>  drivers/usb/dwc2/core.h                        |  9 +++++
>>  drivers/usb/dwc2/params.c                      | 56 ++++++++++++++++++++++++++
>>  3 files changed, 67 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt
>> index 6c7c2bce..9e7b4b4 100644
>> --- a/Documentation/devicetree/bindings/usb/dwc2.txt
>> +++ b/Documentation/devicetree/bindings/usb/dwc2.txt
> 
> according to Documentation/devicetree/bindings/submitting-patches.txt
> this change should be a separate patch.

Ok

> 
>> @@ -26,6 +26,8 @@ Optional properties:
>>  Refer to phy/phy-bindings.txt for generic phy consumer properties
>>  - dr_mode: shall be one of "host", "peripheral" and "otg"
>>    Refer to usb/generic.txt
>> +- snps,ahb-burst: specifies the ahb burst length. Valid arguments are:
>> +  "SINGLE", "INCR", "INCR4", "INCR8", "INCR16". Defaults to "INCR4".
> 
> This doesn't apply in case of the bcm2835. I would prefer this option is
> ignored in that case with a dev_warn("snps,ahb-burst is not supported on
> this platform").

Sure I'll add this.

Regards,
John


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