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

Marek Vasut
2013-07-11T12:35:32Z

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

> >>> +
> >>
> >> 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
>
> "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() ?

Best regards,
Marek Vasut