Hi Jan,
> On Mar 3, 2015, at 15:42 , Jan Lübbe <j...@pengutronix.de> wrote:
>
> Hi Pantelis,
>
> On Fr, 2015-02-27 at 20:55 +0200, Pantelis Antoniou wrote:
>> +3.b) The Device Tree fragments must be compiled with the same option but
>> they
>> +must also have a tag (/plugin/) that allows undefined references to labels
>> +that are not present at compilation time to be recorded so that the runtime
>> +loader can fix them.
>> +
>> +So the bar peripheral's DTS format would be of the form:
>> +
>> +/plugin/; /* allow undefined label references and record them */
>> +/ {
>> + .... /* various properties for loader use; i.e. part id etc. */
>> + fragment@0 {
>> + target = <&ocp>;
>> + __overlay__ {
>> + /* bar peripheral */
>> + bar {
>> + compatible = "corp,bar";
>> + ... /* various properties and child nodes */
>> + }
>> + };
>> + };
>> +};
>> +
>> +Note that there's a target property that specifies the location where the
>> +contents of the overlay node will be placed, and it references the label
>> +in the foo.dts file.
>
> The kernel overlay code also supports using 'target-path="/path";'
> instead of 'target=<phandle>;' to work with base DTBs which have no
> __symbols__ node. Shouldn't this be mentioned here as well?
>
The kernel documentation entries contain all relevant information. This is just
the DTC
support patch, and as such they only need a rough outline of what the actual
in-kernel
resolver and overlay handler code does.
tl;dr DTC has no notion of either target or target-path properties.
> Thanks,
> Jan
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>
Regards
— Pantelis
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