[U-Boot] [PATCH v4 1/2] usb: ehci: add Faraday USB 2.0 EHCI support

[Marek Vasut]

Dear Kuo-Jung Su,

> 2013/5/8 Marek Vasut <marex at denx.de>:
> > Dear Kuo-Jung Su,
> > 
> > [...]
> > 
> >> >> --- a/common/usb_hub.c
> >> >> +++ b/common/usb_hub.c
> >> >> @@ -419,6 +419,14 @@ static int usb_hub_configure(struct usb_device
> >> >> *dev)
> >> >> 
> >> >>                       portstatus = le16_to_cpu(portsts->wPortStatus);
> >> >>                       portchange = le16_to_cpu(portsts->wPortChange);
> >> >> 
> >> >> +#ifdef CONFIG_USB_EHCI_FARADAY
> >> >> +                     /* Faraday EHCI needs a long long delay here */
> >> >> +                     if (!portchange && !portstatus) {
> >> >> +                             if (get_timer(start) < 250)
> >> >> +                                     continue;
> >> >> +                     }
> >> >> +#endif
> >> > 
> >> > I'd say just call a weak function here, in case some other non-EHCI
> >> > compliant controller happened to need this too. btw. does it need to
> >> > be 250 ms or can you poll for readiness somehow ?
> >> 
> >> Got it, thanks. I'll add a weak function later,
> >> and about the 250 ms is actually an estimated value.
> >> The delay time is actually board specific, it looks to me
> >> that it's somehow related to the number of usb host controllers
> >> and the attached usb flash drivers.
> >> 
> >> For example:
> >> 
> >> 1.  A369 - FUSBH200: a usb flash driver attached
> >> 
> >>      A369 - FOTG210: nothing attached
> >> 
> >> => no extra delay required.
> >> 
> >> 2.  A369 - FUSBH200: nothing attached
> >> 
> >>      A369 - FOTG210: a usb flash driver attached
> >> 
> >> => no extra delay required.
> >> 
> >> 3. A369 - FUSBH200: a usb flash driver attached
> >> 
> >>     A369 - FOTG210: a usb flash driver attached
> >> 
> >> => The 2nd ehci host requires 200 ms extra delay to detect the attached
> >> device. So I put a 250ms here for safe.
> > 
> > Urgh, isn't it a PHY problem then? Or can this not be solved like
> > board/genesi/mx51_efikamx/efikamx-usb.c board_ehci_hcd_postinit() or such
> > function?
> 
> It looks to me that it's something related to root hub reset.
> And now I've found that adding a extra delay to usb_hub_power_on()
> would help to resolve this issue.
> So I plan to add a new macro constant for it.
> For example:
> 
> 1. Add this to README:
> CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
> interval for usb hub power-on delay.(minimum 100msec)
> 
> 2. Update usb_hub.c as bellow:
> static void usb_hub_power_on(struct usb_hub_device *hub)
> {
> ......
>     /* Wait at least 100 msec for power to become stable */
>     mdelay(max(pgood_delay, USB_HUB_MIN_POWER_ON_DELAY));
> }

Let's try it.

Best regards,
Marek Vasut