[U-Boot] [PATCH v2] fastboot: OUT transaction length must be aligned to wMaxPacketSize

[B, Ravi]

Tom

> -----Original Message-----
> From: U-Boot [mailto:u-boot-bounces at lists.denx.de] On Behalf Of Tom Rini
> Sent: Saturday, April 09, 2016 1:14 AM
> To: Sam Protsenko
> Cc: Marek Vasut; Steve Rae; U-Boot Mailing List
> Subject: Re: [U-Boot] [PATCH v2] fastboot: OUT transaction length must be aligned to wMaxPacketSize

> On Fri, Apr 08, 2016 at 02:11:48AM +0300, Sam Protsenko wrote:
> [snip]
> > The only actual documentation for fastboot protocol I found is [1], 
> > and I don't see any mention of alignment there at all. So it wouldn't 
> > surprise me if that patch was done just out of of empiric 
> > observations. Which doesn't make it any less significant.
> [snip]
> > [1] 
> > https://android.googlesource.com/platform/system/core/+/master/fastboo
> > t/fastboot_protocol.txt

> So, the protocol says "Max packet size must be 64 bytes for full-speed,
> 512 bytes for high-speed and 1024 bytes for Super Speed USB.".  What are wMaxPacketSize and ep->maxpacket in these cases, both the TI+DWC3 ones,
> Broadcom+DWC2 and if someone can grab one, TI+MUSB.  And then, what
> exactly does everyone failure logs look like, perhaps with some annotations where it fails?

The maxpacket size is 512 bytes. As per TI+DWC3 specification, for device mode the TRB buffer size must be multiple of maximum endpoint packet size.
For usb data reception (including short transfer), the request buffer length shall be multiple of endpoint maxpacket size. 

Regards
Ravi