[U-Boot] [PATCH v3 6/7] USB: usb-hub: Add a weak function for resetting devices

[Marek Vasut <marex@denx.de>]

Dear Dan Murphy,

> Marek
> 
> On 07/17/2013 11:30 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>
> >> ---
> >> v3 - Modified location of the weak function -
> >> http://patchwork.ozlabs.org/patch/258229/
> >> 
> >>  common/usb_hub.c |   12 ++++++++++++
> >>  1 file changed, 12 insertions(+)
> >> 
> >> diff --git a/common/usb_hub.c b/common/usb_hub.c
> >> index 774ba63..c655b75 100644
> >> --- a/common/usb_hub.c
> >> +++ b/common/usb_hub.c
> >> @@ -62,6 +62,10 @@
> >> 
> >>  static struct usb_hub_device hub_dev[USB_MAX_HUB];
> >>  static int usb_hub_index;
> >> 
> >> +__weak void usb_hub_reset_devices(int port)
> >> +{
> >> +	return;
> >> +}
> >> 
> >>  static int usb_get_hub_descriptor(struct usb_device *dev, void *data,
> >>  int
> >> 
> >> size) {
> >> @@ -444,6 +448,14 @@ static int usb_hub_configure(struct usb_device
> >> *dev)
> >> 
> >>  	      "" : "no ");
> >>  	
> >>  	usb_hub_power_on(hub);
> >> 
> >> +	/*
> >> +	 * Reset any devices that may be in a bad state when applying
> >> +	 * the power.  This is a __weak function.  Resettig of the devices
> >> +	 * should occur in the board file of the device.
> >> +	 */
> >> +	for (i = 0; i < dev->maxchild; i++)
> >> +		usb_hub_reset_devices(i + 1);
> >> +
> >> 
> >>  	for (i = 0; i < dev->maxchild; i++) {
> >>  	
> >>  		ALLOC_CACHE_ALIGN_BUFFER(struct usb_port_status, portsts, 1);
> >>  		unsigned short portstatus, portchange;
> > 
> > We hae like 10 reset hooks in the usb code, this means something just
> > isn't right. The device doesn't enumerate, right ? Have you tried
> > waiting a little after releasing the reset and before starting the EHCI
> > ?
> > 
> > Best regards,
> > Marek Vasut
> 
> Sorry for the delay in the response I have been looking heavily into this.
> 
> I see we have many reset hooks but they all seem to mean something for
> different components.
> 
> The one I am introducing is for the device itself and made it weak as there
> are devices that work properly like the 3503.
> 
> What I am finding is that I have to apply port power and then hit the
> device's reset line to get the device to enumerate. Or I can hold the 9730
> device in reset throughout the full USB init sequence and upon releasing
> it after port power the device is detected.
> 
> There is no opportunity to release the reset while the USB detection state
> machine is running
> 
> I have contacted the vendor to see if there are any known anomalies with
> this part if there is then I can document this in the commit.

Sigh, ok, that's unfortunate. I keep wondering how come it works in Linux. But 
anyway, if the manufacturer won't come up with anything, we will apply this 
stuff.

Best regards,
Marek Vasut