[PATCH V3 0/6] ARM64: Add support for FSL's LS2085A SoC

Stuart Yoder
2014-09-24T14:50:04Z

So there is still an open issue that has not been closed related to
what device trees should have with respect to enable-method. There
are 2 proposals from Mark and Arnd--

1. Put comment in /cpus node in dts (Mark)

...
cpus {
#address-cells = <2>;
#size-cells = <0>;

/*
* We expect the enable-method to be "psci", but this is dependent on
* the FW, which will fill this in.
*/

cpu at 0 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x0>;
};
...

2. Put explicit psci enable-method in cpu nodes, to make it clear that psci
is expected. Plus include empty psci node with a comment. (Arnd)

...
/*
* We expect the enable-method to be "psci", but this is dependent on
* the FW, which will fill this in.
*/
psci {
}
...
cpus {
#address-cells = <2>;
#size-cells = <0>;

cpu at 0 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x0>;
enable-method = "psci";
};
...

I would prefer #1. I think putting "hints" like the psci node and
the enable-method are weak at best. I think the comment in #1 is
enough to make the preferred approach clear. In the end firmware will
override the nodes and properties if it wants or needs to.

Thanks,
Stuart