diff mbox

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

Message ID 1782709.QdZpsrsctf@phil
State Superseded, archived
Headers show

Commit Message

Heiko Stübner Jan. 20, 2014, 3:42 p.m. UTC
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@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Ulrich Prinz <ulrich.prinz@googlemail.com>
Acked-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/misc/sram.txt |    8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Heiko Stübner Feb. 5, 2014, 12:05 p.m. UTC | #1
Am Mittwoch, 5. Februar 2014, 11:12:47 schrieb Grant Likely:
> On Mon, 20 Jan 2014 16:42:58 +0100, Heiko Stübner <heiko@sntech.de> 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@gmail.com>
> > Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> > Tested-by: Ulrich Prinz <ulrich.prinz@googlemail.com>
> > Acked-by: Rob Herring <robh@kernel.org>
> > ---
> > 
> >  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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diff mbox

Patch

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.
+
 Example:
 
 sram: sram@5c000000 {
 	compatible = "mmio-sram";
 	reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
+	mmio-sram-reserved = <0x0 0x100>; /* reserve 0x5c000000-0x5c000100 */
 };