[PATCH v20 14/14] Documentation: dt: usable-memory and elfcorehdr nodes for arm64 kexec

[Michael Ellerman]

On Mon, 2016-06-27 at 15:22 -0300, Thiago Jung Bauermann wrote:
> Am Donnerstag, 23 Juni 2016, 17:54:49 schrieb Geoff Levand:
> > +linux,usable-memory
> > +-------------------
> > +
> > +This property is set on PowerPC and arm64 by kexec-tools during kdump
> > +to tell the crash kernel the base address of its reserved area of memory,
> > and +the size. e.g.
> > +
> > +/ {
> > +	chosen {
> > +		linux,usable-memory = <0x9 0xf0000000 0x0 0x10000000>;
> > +	};
> > +};
> 
> On powerpc, linux,usable-memory isn't in /chosen. It is put by kexec-tools 
> in each /memory node and has the same format as the reg property. During 
> early boot, the kernel goes through the /memory nodes to find usable memory 
> and for each node, if there's a linux,usable-memory property it will use it 
> instead of the reg property to find the ranges of memory it can use (see 
> early_init_dt_scan_memory in drivers/of/fdt.c).

Yep that sounds right to me.

Added in:

ba7594852f4e ("[PATCH] powerpc: Add support for "linux,usable-memory" on memory nodes")

cheers