Subject: Re: [PATCH net-next 1/2] net: davinci_mdio: don't request io address range

From: Tony Lindgren <[email-masked]>
Date: Fri, 27 Feb 2015 08:51:01 -0800

* Murali Karicheri <[email-masked]> [150224 13:32]:
> From: Grygorii Strashko <[email-masked]>
> 
> Historically Davinci MDIO driver was  created with assumption that
> MDIO is standalone device, but for Keystone 2 it's a part
> of NETCP module and now NETCP driver requests IO range which
> includes MDIO IO range too. This causes Keystone 2 networking stack
> failure during the boot.
> 
> "netcp-1.0 2620110.netcp: Probe of module(netcp-gbe) failed with -16"
> 
> Hence, don't request io address range from Davinci MDIO driver and
> just remap it.

Best to fix this up properly so you don't have overlapping resources.
You probably want to have the whole hardware driver block defined
in the dts file as a single entry, and then have the modules within
that hardware block use the dt ranges property. This allows you to
do standard Linux drivers without any extra hacks.

Sounds like this following untested imaginary example should do
the trick:

mac: ethernet@deadbeef {
	compatible = "ti,cpsw", "simple-bus";
	reg = <0xdeadbeef 0x1000>;
	ranges = <0 0xdeadbeef 0x2000>;
	...

	davinci_mdio: mdio@1000 {
		reg = <0x1000 0x100>;
		...
	};
};

That allows you to get rid of all the existing code for dealing
with the chilren with for_each_child_of_node(node, slave_node)
in cpsw_probe_dt() as that all happens automatically for you and
does not cause problems with modules being moved around.

Regards,

Tony