RE: [PATCH 10/11] Add MPC8360EMDS board support

-----Original Message-----
From: Kumar Gala [mailto:galak@kernel.crashing.org]
Sent: Wednesday, September 27, 2006 9:34 PM
To: Li Yang-r58472
Cc: Vitaly Bordug; linuxppc-dev@ozlabs.org; Paul Mackerras
Subject: Re: [PATCH 10/11] Add MPC8360EMDS board support
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+memory {
+               device_type =3D "memory";
+               linux,phandle =3D <300>;
+               reg =3D <00000000 4000000 f4500000 00000020>;
+       };
the second pair is about bcsr and its size.

Just in case this may help (and wondering if I'm not violating

something :) )

Well, this can make it work.  But I would prefer to use a new node
because the BCSR is by no means a memory type of device.  I have

made my

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change to use node like this:

        bcsr@f8000000 {
                device_type =3D "board-control";
                reg =3D <f8000000 8000>;
        };

I though about that approach, but saw somewhere a reference that we

should not summon

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new node types without utter necessity, and utilized memory because

bcsr is

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memory-mapped stuff. I can hardly imagine bcsr as a device (which

would require

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respective spec inclusion btw).

Well I didn't see such a guideline.  However BCSR is truly a device
like
any other peripherals on board.  Usually it is an FPGA on local bus

to

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control the board.

=20
Agree that a new node is better, calling it memory isn't right.
However, I'm not sure this really needs a node in the device tree.
The BCSR isn't really the same from board to board last time I
checked.  I'd be interested in Paul's thinking about why it should be
in the tree.
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hence let's open a discussion what others think about that. The

problem seems common

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(and for some boards
is called somewhat else apparently), but at this point we should

come

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to some

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conclusion, document it, and use it.

Agreed.  As we are adding more devices to the device tree, we should
also have a guideline clearly stated for adding new nodes.

I'm adding MURAM as a new node under QE bus.  Please comment.
                muram@10000 {
                        device_type =3D "memory";
                        ranges =3D <0 00010000 0000c000>;

                        data-only@0{
                                reg =3D <0 c000>;
                        };
                };

=20
What was the need for this?

Data-only defines MURAM area which can be allocated for data and
parameter ram.  Some MURAM space can be occupied by microcode or
microcode patch, and should be excluded from allocation.

- Leo