Re: [PATCH v3 6/7] USB: EHCI: make ehci-msm a separate driver

From: Alan Stern
Date: Fri Mar 29 2013 - 16:12:39 EST


On Thu, 28 Mar 2013, Arnd Bergmann wrote:

> From: Manjunath Goudar <manjunath.goudar@xxxxxxxxxx>
>
> Separate the Qualcomm QSD/MSM on-chip host controller driver from
> ehci-hcd host code so that it can be built as a separate driver module.
> This work is part of enabling multi-platform kernels on ARM;
> however, note that other changes are still needed before Qualcomm QSD/MSM
> can be booted with a multi-platform kernel, which is not expected before
> 3.11.
>
> With the infrastructure added by Alan Stern in patch 3e0232039
> "USB: EHCI: prepare to make ehci-hcd a library module", we can
> avoid this problem by turning a bus glue into a separate
> module, as we do here for the msm bus glue.

This patch is good. However the ehci-msm driver itself is not. While
checking through the code, I was struck by the fact that it never calls
usb_add_hcd() or usb_remove_hcd(). Obviously the driver cannot work
properly.

In addition, it stores the PHY pointer in a global variable.
(ehci-atmel does much the same thing for its clocks.) This means the
driver cannot be used on a system having more than one EHCI controller.
Maybe this doesn't matter, though.

Maybe somebody would like to fix and test it...

Alan Stern

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