On Thu, Mar 13, 2025 at 01:57:30PM -0500, Rob Herring wrote: > On Thu, Mar 13, 2025 at 9:03 AM Abhishek Tiwari > <[email protected]> wrote: > > > > Add Documentation for linux,usable-memory > > > > Signed-off-by: Abhishek Tiwari <[email protected]> > > --- > > .../bindings/linux,usable-memory.txt | 32 +++++++++++++++++++ > > 1 file changed, 32 insertions(+) > > create mode 100644 > > Documentation/devicetree/bindings/linux,usable-memory.txt > > > > diff --git a/Documentation/devicetree/bindings/linux,usable-memory.txt > > b/Documentation/devicetree/bindings/linux,usable-memory.txt > > new file mode 100644 > > index 000000000000..167054d2e9a2 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/linux,usable-memory.txt > > @@ -0,0 +1,32 @@ > > +linux,usable-memory > > +=================== > > This belongs here: > https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/memory.yaml > > > + > > +Description > > +----------- > > +The ``linux,usable-memory`` property can be used to restrict usable memory > > +region. This property holds a base address and size, Memory outside of this > > +range is not accessible by the kernel. This property is particularly useful > > +in specialized hardware platforms where certain memory regions must be > > +reserved for specific use. > > + > > +Common use cases include: > > +- Allocating ``ramoops`` region > > +- Reserving memory for hardware-specific needs > > +- Fake Protecting persistent memory (PMEM) > > All these examples belong in /reserved-memory nodes, not > linux,usable-memory. Go see the ramoops binding for example. > > This was really for the case where you already have 'reg' (in the > memory node), but need to limit memory while at the same time not > overwriting 'reg'. Basically, for kexec where you can keep booting > another kernel forever. If that's not your usecase, you shouldn't be > using this. > > Rob
Thank you for your suggestions and explanations. I will update the definition and examples accordingly, and submit a PR with the documentation for this property in the specified repository.
