[U-Boot] [[PATCH v2 5/6] USB: ehci: Add a weak function for resetting devices

[Marek Vasut <marex@denx.de>]

Dear Dan Murphy,

> Roger
> 
> On 07/11/2013 09:23 AM, Roger Quadros wrote:
> > Hi Marek,
> > 
> > On 07/11/2013 03:35 PM, Marek Vasut wrote:
> >> Dear Roger Quadros,
> >> 
> >>> On 07/11/2013 02:16 AM, Dan Murphy wrote:
> >>>> On 07/10/2013 05:20 PM, Marek Vasut wrote:
> >>>>> Dear Dan Murphy,
> >>>>> 
> >>>>>> Add a __weak function that can be overridden to reset devices
> >>>>>> attached to an ehci devices after the FEAT_POWER has been submitted
> >>>>>> 
> >>>>>> Signed-off-by: Dan Murphy <dmurphy@ti.com>
> >>>>>> ---
> >>>>>> 
> >>>>>>  drivers/usb/host/ehci-hcd.c |    7 +++++++
> >>>>>>  1 file changed, 7 insertions(+)
> >>>>>> 
> >>>>>> diff --git a/drivers/usb/host/ehci-hcd.c
> >>>>>> b/drivers/usb/host/ehci-hcd.c index 706cf0c..fdd3994 100644
> >>>>>> --- a/drivers/usb/host/ehci-hcd.c
> >>>>>> +++ b/drivers/usb/host/ehci-hcd.c
> >>>>>> @@ -616,6 +616,11 @@ __weak uint32_t
> >>>>>> *ehci_get_portsc_register(struct ehci_hcor *hcor, int port) return
> >>>>>> (uint32_t *)&hcor->or_portsc[port];
> >>>>>> 
> >>>>>>  }
> >>>>>> 
> >>>>>> +__weak void ehci_reset_attached_devices(int port)
> >>>>>> +{
> >>>>>> +	return;
> >>>>>> +}
> >>> 
> >>> Does this function need to be ehci specific? Other USB controllers
> >>> might also need such a function.
> >> 
> >> You'd need to implement this for each of the xHCIs
> > 
> > OK.
> 
> I can move the API to the usb-hub to call this after the FEAT_POWER is
> completed
> 
> >>>>>> +
> >>>>> 
> >>>>> Can the reset not happen elsewhere?
> >>>> 
> >>>> I have tried to move this around and keep this out of this file
> >>>> completely but nothing else seems to work.
> >>>> 
> >>>> For port 2 where the USB3530 is we don't have the issue the 3530
> >>>> enumerates properly.
> >>>> 
> >>>> I did not see any information in the data sheet eluding to a timing
> >>>> issue.
> >>> 
> >>> This is the information I had received earlier from SMSC about USB3503A
> >>> hub
> 
> This has nothing to do with the 3503A this is the LAN9730.  The 3503 works
> just fine without the additional reset.
> 
> >>> "You need the host up and running, and ready to go, THEN negate
> >>> RESET_N. That is probably 95% of the issues."
> >>> 
> >>> Please make sure the following sequence is done.
> >>> 
> >>> - power up hub (RESET is active at this point).
> >>> - start USB controller
> >>> - wait a few ms
> >>> - release hub RESET.
> >>> 
> >>> giving a quick look at the u-boot code it seems you need to release the
> >>> hub reset after usb_lowlevel_init() _OR_ usb_init() returns.
> >> 
> >> Then it would also work in usb_lowlevel_init() ?
> > 
> > It should as long as we place the "release reset" after EHCI controller
> > has started. Maybe safer to put it in the end of usb_lowlevel_init().
> > 
> > cheers,
> > -roger
> 
> I moved the reset to the usb_lowlevel_init and it did not work.
> I tried holding the 9730 in reset until after ehci hcd init is complete and
> pulled it out of reset once the hcd is initialized but still no
> enumeration.

Can you try waiting a little after negating the reset ? It might be that the 
device takes some time to come back to life.

Best regards,
Marek Vasut