Re: [RFCv2 3/3] ARM: dts: N900: Add SSI information

[Sebastian Reichel <sre@ring0.de>]

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On Thu, Nov 21, 2013 at 12:46:55PM -0800, Tony Lindgren wrote:
> * Sebastian Reichel <sre@debian.org> [131120 18:22]:
> > On Wed, Nov 20, 2013 at 05:38:59PM -0800, Tony Lindgren wrote:
> > 
> > In the public documentation of the omaps all SSI related stuff is
> > missing and memory areas are marked as reserved. I could not find
> > out how to receive the NDA version, so the following is purely
> > speculation based on the code.
> > 
> > If I understand it right the HW looks like this:
> > 
> > +-----------------+
> > |    GDD (DMA)    | <- this one is currently called ssi-controller
> > +--------+--------+
> > | Port 1 | Port 2 | <- these are currently called ssi-port
> > +--------+--------+
> > 
> > I think the GDD part must be enabled while Port 1 or Port 2 is
> > enabled. The last RFC driver from Carlos did not even split up the
> > irq/memory areas into different platform devices, but just requested
> > all of them in one ssi platform device.
> 
> Might be worth checking. If these blocks have the revision and SYSC
> register in the beginning of their address space like all omap modules,
> then they are completely separate blocks and can idle independently.

This does not seem to be the case.
I think this is just one big IP-Core, which provides two ports.

> The fact that they have separate interrutps makes me think that's the
> case, otherwise there would be just interrupt(s) at the ssi-controllel
> level.

The original driver from Carlos had all IRQs in one big platform
device. I created the ports subdevices, since it looked cleaner
than naming resources "port1_mpu_irq0".

-- Sebastian

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