[U-Boot] Signed-off-by for RPI U-Boot USB patches

Lukasz Majewski l.majewski at samsung.com
Tue Feb 4 01:29:50 EST 2014

Hi Stephen,

> On 02/03/2014 01:23 AM, Lukasz Majewski wrote:
> > Hi Stephen,
> > 
> >> (Sorry for the spam; resending with the correct U-Boot mailing list
> >> in CC)
> >>
> >> On 02/01/2014 11:14 PM, Stephen Warren wrote:
> >>> Oleksandr, I'm starting to look at getting USB support enabled for
> >>> the Raspberry Pi in mainline U-Boot. To that end, I looked at:
> >>>
> >>> git://github.com/gonzoua/u-boot-pi.git rpi
> >>>
> >>> I took the DWC driver from there and applied it to a very recent
> >>> mainline U-Boot. It works very well:-)
> > 
> > Could you be more specific about the exact DWC USB IP block, which
> > you plan to port for PI?
> > 
> > Is this host or device controller?
> > 
> > The USB controller designed by DesignWare is very popular (at least
> > the USB 2.0) in the industry.
> > 
> > For example in u-boot there already is s3c_udc_*.c implementation
> > for device controller. Also you can look into the s3c_hsotg.c in
> > the linux mainline kernel.
> It's a driver for the DWC2 IP block, acting as a host controller (I
> don't know if this one can act as a device or not).

As fair as I remember the mainline dwc2 is only for host. The one about
which I've mentioned is a USB device driver (for the same IP block), so
probably there is a little chance to reuse the existing code.

> (part of my upstreaming process will likely require s/dwc/dwc2/
> everywhere, since I know there's at least a DWC3 in the kernel, and I
> would assume that means there could be a DWC1 somewhere too).

I doubt that there is a DWC1 driver. DWC2 indicates (probably) that the
IP block works with devices up to USB 2.0. In the same manner DWC3
indicates Super Speed (3.0).

The goal of my question was to reuse/improve existing code for the same
IP block.

Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group

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