[U-Boot] USB detection

Albert ARIBAUD albert.u.boot at aribaud.net
Mon Jul 9 14:18:20 CEST 2012


Hi Manukumar,

On Mon, 09 Jul 2012 14:17:49 +0530, Manukumar
<manukumar at signal-networks.com> wrote:
> hello
> I checked with the hardware spec
> in that
> P1020RDB: having connection like 
> P1012processor -> PHY -> HUB -> ports
> 
> whereas in custom board
> P1012processor -> phy -> port(single usb port)
> 
> In uboot source code initializing sequence of u-boot
> is below:
> 1.usb_init()
> 2.usb_scan_devices()
> 3.usb_new_device(dev)
> 4.usb_hub_probe(dev, 0)
> 5.usb_hub_configure(dev)
> 
> 
> how can we do this in u-boot source code

I am not a USB specialist, but it seems like it is the first time ever
that U-Boot meets a board where the core's USB port is mapped directly
to a device without passing through a hub. Is this design compliant
with the USB standards?

Anyway, you seem to have nailed the (USB) root cause, so the course of
action is obvious even if its compliance with standards is not: you
need to make usb hub probing and configuration optional and enabled by
default, and to disable this option for your custom board.

> manukumar
> signal-networks

Amicalement,
-- 
Albert.


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