[PATCH 1/2] ARM: kirkwood: Basic support for DNS-320 and DNS-325

[Jason Cooper]

On Sun, Mar 11, 2012 at 05:46:09PM +0000, Arnd Bergmann wrote:
> On Sunday 11 March 2012, Jamie Lentin wrote:
> > Add support for the DNS-320 and DNS-325. Describe as much as currently possible
> > in the devicetree files, leave everything else in board-dt.c to be patched
> > later.
> > 
> > Signed-off-by: Jamie Lentin <jm at lentin.co.uk>
> 
> Great work!
> 
> > +
> > +/ {
> > +	model = "D-Link DNS-320 NAS (Rev A1)";
> > +	compatible = "dlink,dns-320-a1", "dlink,dns-320", "dlink,dns-kirkwood", "marvell,kirkwood-88f6281", "marvell,kirkwood";
> > +
> > +	memory {
> > +		device_type = "memory";
> > +		reg = <0x00000000 0x8000000>;
> > +	};
> > +
> > +	chosen {
> > +		bootargs = "console=ttyS0,115200n8 earlyprintk";
> > +	};
> > +
> > +	wdt at fed20300 {
> > +		compatible = "mrvl,orion-wdt";
> > +		reg = <0xfed20300 0x28>;
> > +		clock-frequency = <166666667>;
> > +	};
> > +
> > +	serial at f1012000 {
> > +		compatible = "ns16550a";
> > +		reg = <0xf1012000 0xff>;
> > +		reg-shift = <2>;
> > +		interrupts = <33>;
> > +		clock-frequency = <166666667>;
> > +	};
> > +
> > +	serial at f1012100 {
> > +		compatible = "ns16550a";
> > +		reg = <0xf1012100 0xff>;

oops, I missed this earlier (and, I just corrected in my own code).
Arnd says Linux uses inclusive sizes, so the above should be 0x100.
Please correct for all register sizes.

> > +		reg-shift = <2>;
> > +		interrupts = <34>;
> > +		clock-frequency = <166666667>;
> > +	};
> 
> I think the generic kirkwood device nodes should all be part of
> the kirkwood.dtsi file, except for any properties you want to
> override.
> 
> You can add a status="disabled" property in device nodes
> that may not be connected in individual boards, and then
> just override it by listing status="enabled" in the board.dts
> file, without having to duplicate all the other properties.

The clock-frequency property complicates that, since it is different
from board to board.  of_serial appears to print an error message if
clock-frequency isn't set, so would this work:

### blah.dtsi ###
...
	serial at f1012100 {
		compatible = "ns16550a";
		reg = <0xf1012100 0xff>;
		reg-shift = <2>;
		interrupts = <34>;
		/* no clock set */
		status = "disabled";
	}
#################

then,

### blah-foo.dts ###
...
	serial at f1012100 {
		status = "ok";
		clock-frequency = <166666667>;
	}
####################

> I would also suggest to change the kirkwood.dtsi layout to
> put all the on-chip peripherals from the 0xf1 section into
> one bus in the device tree, like
> 
> 	ocp at f1000000 {
> 		compatible = "simple-bus";
> 		ranges = <0xf1000000 0xf1000000 0x1000000>;
> 		#address-cells = 1;
> 		#size-cells = 1;
> 
> 		serial at f1012000 {
> 			...
> 		};
> 
> 		...
> 	};
> 
> Or even use the ranges property to remap everything into
> a simpler address range:
> 
> 	ocp at f1000000 {
> 		compatible = "simple-bus";
> 		ranges = <0 0xf1000000 0x1000000>;
> 		#address-cells = 1;
> 		#size-cells = 1;
> 
> 		serial at 12000 {
> 			reg = <0x12000 0x100>;
> 			...
> 		};
> 
> 		...
> 	};

Okay, that's pretty slick.  The wdt and intc are at 0xfed00000, is that
another ocp bus?  Or, am I missing something?

thx,

Jason.