[U-Boot] [PATCH 8/8] config: smdk5420: Enable support for multiple XHCI controllers

[Vivek Gautam]

HI Marek,


On Mon, Jan 6, 2014 at 9:24 PM, Marek Vasut <marex at denx.de> wrote:

Thanks for reviewing this. :-)

> On Monday, January 06, 2014 at 10:29:43 AM, Vivek Gautam wrote:
>> Update USB_MAX_CONTROLLER_COUNT to be '2' to enable support
>> for both usb 3.0 controllers on exynos5420.
>>
>> NOTE: To use EHCI on exynos5420, this change will need to be
>> reverted, since there's only one EHCI controller available on
>> exynos5420.
>
> OK, this I seriously dislike. Hence a question ... my feeling is the XHCI and
> EHCI code for handling multiple controllers and multiple ports is almost the
> same. Can this code be adjusted to handle both EHCI and XHCI controllers
> indiscriminately ?

The controller count is actually used by the usb core (common/usb*)
framework, right ?
There's a need to add support for multiple controller types actually
(so that EHCI
and XHCI can be enabled simultaneously). Is that what you mean here ?

>
> This would result in having CONFIG_USB_MAX_CONTROLLER_COUNT 3 on this board and
> being able to use both EHCI and XHCI . Would this be possible for you to
> implement please ? Thanks !

Ok, so you mean get all the controllers present on the board (EHCI and
XHCI) setup.
I think right now, the way USB core handles the controller count is
quite different, so
that 'CONFIG_USB_MAX_CONTROLLER_COUNT' helps in probing multiple controllers
of the same type.
I had plans to add support to use controllers of different types (EHCI
and XHCI etc) simultaneously.
But haven't really put a code for that yet.
Can you suggest some pointers about how would you like to see EHCI and
XHCI or even OHCI work
together :-)
I can take up this.

>
> Best regards,
> Marek Vasut
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-- 
Best Regards
Vivek Gautam
Samsung R&D Institute, Bangalore
India