Re: query on DWC3
From: sundeep subbaraya
Date: Mon Jan 19 2015 - 01:06:12 EST
Hi Felipe,
On Thu, Jan 8, 2015 at 10:27 PM, Felipe Balbi <balbi@xxxxxx> wrote:
> Hi,
>
> On Tue, Jan 06, 2015 at 12:39:55PM +0530, sundeep subbaraya wrote:
>> >> On Sun, Dec 14, 2014 at 08:39:18AM +0530, sundeep subbaraya wrote:
>> >> > Hi Paul,
>> >> >
>> >> > As per my understanding, for BULK OUT we do queue a request with 512
>> >> > bytes length since we do not
>> >>
>> >> sometimes we _do_ know the size. In case of Mass Storage, we _know_ that
>> >> the first bulk out transfer will be 31-bytes (CBW), if we were to start
>> >> a 31-byte transfer, we would't receive anything.
>> >>
>> >> > know the length of the transfer Host is going to send. For Control OUT
>> >> > we know the length in wLength of
>> >> > Setup packet, hence I assumed there is no difference in programming
>> >> > model of Control IN and OUT.
>> >>
>> >> there is _no_ difference. It's just that it was agreed that for anything
>> >> other than control ep, the function drivers would take care of it. See
>> >> the uses of quirk_ep_out_aligned_size.
>>
>> got it..:)
>>
>> >
>> > btw, why are you reimplementing the driver when there's a perfectly good
>> > driver to use in mainline kernel ?
>>
>> I am writing a bare metal driver and it didn't work without alignment
>> check mentioned above.
>
> just make sure you don't copy GPL code into your bare metal driver,
> otherwise your bare metal driver will be GPL by definition. Also, since
I didn't copy linux code. I have gone through dwc3 driver while
writing udc-xilinx.c
and now it is helping me to understand dwc3 controller quickly.:)
> you're not using Linux at all, you should be asking support from
> Synopsys instead, not the Linux USB mailing list.
Sure will ask support from Synopsis.
Thanks,
Sundeep
>
> --
> balbi
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