Help on MPC82XX USB Host controller Development using m82xx-hcd.

Laurent Pinchart laurentp at
Wed Jun 4 20:29:29 EST 2008

Hi Naren,

On Wednesday 04 June 2008 12:12, gforgcc wrote:
> Laurent Pinchart-4 wrote:
> > 
> > The cpm2usb project isn't maintained. If possible you should upgrade to a
> > more recent kernel and switch to the powerpc architecture where a new USB
> > driver called fhci is available.
> > 
> > The MPC872ADS is supported in recent kernels so switching shouldn't be too 
> > difficult.
> > 
> > 
> Hi Laurent,
> i have some basic queries, i have some knowledge on what is UHCI or OHCI,
> but can you please brief me what is FHCI and some info regarding this ?
> googling on this dint help me much.. :(

FHCI stands for Freescale Host Controller Interface. The term is unofficial 
and not referenced in the CPM documentation.

> we are using powerpc architecture with latest kernel 2.6.25.. and trying to
> implement the USB host controller driver and have similar problems.. 

The good news is that Anton Vorontsov wrote and posted a FHCI driver for 
QE-based parts on the linux-ppc mailing list (search the archive for "[PATCH] 
Freescale QUICC Engine USB Host Controller"). The driver can be easily 
modified to work with CPM2-based parts.

The bad news is that, from my experience with the CPM2, the controller is 
almost unusable. It eats around 40% CPU time on my MPC8248 system, and 
requires software help to generate SOF tokens, which results in bad SOF 
tokens being sent on the bus. Most USB disks don't seem to care, but all the 
USB Bluetooth host controllers I've tested crashed.

We will be looking for an external USB host controller (or even another CPU) 
for the next revision of the design.

Best regards,

Laurent Pinchart
CSE Semaphore Belgium

Chaussee de Bruxelles, 732A
B-1410 Waterloo

T +32 (2) 387 42 59
F +32 (2) 387 42 75
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