Re: [PATCH v7 2/7] dt-bindings: sram: describe option to reserve parts of the memory

From: Heiko Stübner
Date: Wed Feb 05 2014 - 07:06:26 EST


Am Mittwoch, 5. Februar 2014, 11:12:47 schrieb Grant Likely:
> On Mon, 20 Jan 2014 16:42:58 +0100, Heiko Stübner <heiko@xxxxxxxxx> wrote:
> > Some SoCs need parts of their sram for special purposes. So while being
> > part of the peripheral, it should not be part of the genpool controlling
> > the sram.
> >
> > Therefore add an option mmio-sram-reserved to keep arbitrary portions of
> > the sram from general usage.
> >
> > Suggested-by: Rob Herring <robherring2@xxxxxxxxx>
> > Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
> > Tested-by: Ulrich Prinz <ulrich.prinz@xxxxxxxxxxxxxx>
> > Acked-by: Rob Herring <robh@xxxxxxxxxx>
> > ---
> >
> > Documentation/devicetree/bindings/misc/sram.txt | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/misc/sram.txt
> > b/Documentation/devicetree/bindings/misc/sram.txt index 4d0a00e..09ee7a3
> > 100644
> > --- a/Documentation/devicetree/bindings/misc/sram.txt
> > +++ b/Documentation/devicetree/bindings/misc/sram.txt
> >
> > @@ -8,9 +8,17 @@ Required properties:
> > - reg : SRAM iomem address range
> >
> > +Optional properties:
> > +
> > +- mmio-sram-reserved: ordered list of reserved chunks inside the sram
> > that
> > + should not be used by the operating system.
> > + Format is <base size>, <base size>, ...; with base being relative to
> > the
> > + reg property base.
> > +
>
> We've now got a draft binding for reserved memory. Can you use the format
> here? Basically each reserved region is a sub node with either a reg
> property or a size property.
>
> This is specifically for sram, so I won't make a big deal about it, but
> it would be good to have some commonality.

I guess you're talking about "[PATCH v2 0/5] reserved-memory regions/CMA in
devicetree, again", right?

In general I'm all for commonality :-). So I guess you mean it to look
something like the following:

sram: sram@10080000 {
compatible = "rockchip,rk3066-sram", "mmio-sram";
reg = <0x10080000 0x8000>;

reserved-memory {
#address-cells = <1>;
#size-cells = <1>;

smp@200 {
/* hmm, relative or absolute, aka 0x200 or 0x10080200? */
reg = <0x200 0x50>;
};
};
};

As it looks like only a slight modification of my "parsing" code this should be
doable. Do you suggest more changes to the example above?


Heiko


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