[U-Boot] [PATCH 1/6] usb: dwc2: Add support for v3 snpsid value

[Marek Vasut]

On Wednesday, May 13, 2015 at 01:00:01 PM, Peter Griffin wrote:
> Hi Marek,
> 
> On Tue, 12 May 2015, Marek Vasut wrote:
> > On Tuesday, May 12, 2015 at 03:38:27 PM, Peter Griffin wrote:
> > > This has been tested to the extent that I can enumerate
> > > a asix usb networking adapter and boot a kernel over usb
> > > on the 96boards hikey u-boot port I'm currently doing.
> > > 
> > > Signed-off-by: Peter Griffin <peter.griffin at linaro.org>
> > > ---
> > > 
> > >  drivers/usb/host/dwc2.c | 3 ++-
> > >  drivers/usb/host/dwc2.h | 1 +
> > >  2 files changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
> > > index e8142ac..19a6007 100644
> > > --- a/drivers/usb/host/dwc2.c
> > > +++ b/drivers/usb/host/dwc2.c
> > > @@ -1015,7 +1015,8 @@ int usb_lowlevel_init(int index, enum
> > > usb_init_type init, void **controller) snpsid = readl(&regs->gsnpsid);
> > > 
> > >  	printf("Core Release: %x.%03x\n", snpsid >> 12 & 0xf, snpsid &
> > >  	0xfff);
> > > 
> > > -	if ((snpsid & DWC2_SNPSID_DEVID_MASK) != DWC2_SNPSID_DEVID_VER_2xx) {
> > > +	if ((snpsid & DWC2_SNPSID_DEVID_MASK) != DWC2_SNPSID_DEVID_VER_2xx &&
> > > +	    (snpsid & DWC2_SNPSID_DEVID_MASK) != DWC2_SNPSID_DEVID_VER_3xx) {
> > 
> > Isn't this then a DWC3 controller instead ?
> 
> No I don't believe so. dwc3 is a usb3 controller with different register
> set AFAIK.
> 
> I believe this piece of code is replicating what the Linux
> driver does here: -
> 
> http://lxr.free-electrons.com/source/drivers/usb/dwc2/core.c#L2664
> 
> Also see here for the various different sub core revisions within 2.xx and
> 3.xx which are supported by the dwc2 Linux driver
> http://lxr.free-electrons.com/source/drivers/usb/dwc2/core.h#L625.
> 
> This also matches up with the available datasheet here
> https://github.com/96boards/documentation/blob/master/hikey/
> Hi6220V100_Multi-Mode_Application_Processor_Function_Description.pdf on
> page 219 which states it is a USB2 OTG controller, but near the bottom of
> the page also tates: -
> 
> "The USB core used in Hi6220 is build from Synopsys IP(3.00a).".
> 
> I just checked through the DWC_otg_databook.odf, and these revision numbers
> also match up with the "Revision History" changes in the document. So it
> all ties together.
> 
> It is worth highlighting at this point that not bailing here (along with
> setting up the appropriate clocks to the IP) was enough for me to get a
> DWC2 core rev 3.00a enumerating a ASIX networking adapter and tftp a
> kernel into DDR. However there maybe some other changes required to
> "fully" support the 3.00a hardware version. There is of course the problem
> I mentioned in the cover letter regarding enumerating mass storage devices
> which may or may not be related to this.
> 
> Although a quick grep of the Linux driver only gets three hits
> 
> git grep DWC2_CORE_REV_3_00a
> core.h:#define DWC2_CORE_REV_3_00a      0x4f54300a
> core_intr.c:            if (hsotg->hw_params.snpsid >= DWC2_CORE_REV_3_00a)
> hcd.c:  if (hsotg->hw_params.snpsid >= DWC2_CORE_REV_3_00a) {
> 
> Neither of which seem relevant to the mass storage device problem (one adds
> a delay in the irq handler, and the other sets a bit when freeing the hcd.

Ooh, I see. Thank you for the extensive explanation!

I picked this patch for u-boot-usb, so feel free to submit any improvements
for the 3.xx core as you cook them. Thanks!