Re: Driver(s) for Synopsys' DesignWare USB OTG

On Sun, Jan 8, 2012 at 8:56 PM, Nikolai Zhubr [off-list ref] wrote:

Hello Piter,


08.01.2012 7:12, you wrote:

quoted

2012/1/8 Nikolai Zhubr[off-list ref]:

quoted

Hello developers,

I'm trying to find/combine/fix a driver for Synopsys' DesignWare USB
controller. This thing is USB 2.0 host/slave/otg capable and is used in
various SoCs including Amlogic 8726M, Ralink RT305x, and probably more.

[...trim...]

quoted

Please see:
http://marc.info/?l=linux-usb&m=129906859817430&w=2

Ah, thanks. So sadly uncoordinated work in this area is quite common.
However, in case of Synopsys the situation is even more disappointing
because initially it _was_ a single driver! What probably lacked was some
shared repository and proper communication between developers to stay in
sync. Maybe there were also licensing issues at some point, though currently
file headers contain rather reasonable (imho) permissive license from
Synopsys.

I think the challenge of cooperation in situation like this is that
most companies don't like to advertise the source of the licensed IP
block.  Even the owner of the IP block doesn't list all users of the
block(maybe business requirement). It was really hard to find out if
the same IP has been used by anyone else.  Also the owner of this USB
IP block has been changed for several times(ARC, TDI, ChipIdea, and
Synopsys) which made it even more difficult to tell.

quoted

I am not sure we can combine all Synopsys USB drivers to single file, but
we

Synopsys driver which I examine consists of 16 files (each of 2 versions),
200k lines total. I've already perpared some few smaller files for version
merging. So probably it is doable, but quite a lot of work, therefore I
wouldn't like it to be wasted.

I didn't examine the Synopsys driver myself.  But if it is so complex
as you described, it might be better to start with the in-tree drivers
IMO.

- Leo