Re: [PATCH v2 01/11] soc: qcom: Add device tree binding for SMEM

Bjorn Andersson
2015-07-13T22:31:01Z

On Wed 08 Jul 16:56 PDT 2015, Stephen Boyd wrote:

> On 06/26/2015 02:50 PM, bjorn@kryo.se wrote:
> > += EXAMPLE
> > +The following example shows the SMEM setup for MSM8974, with a main SMEM region
> > +at 0xfa00000 and an auxiliary region at 0xfc428000:
> > +
> > + reserved-memory {
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > + ranges;
> > +
> > + smem_region: smem@fa00000 {
> > + reg = <0xfa00000 0x200000>;
> > + no-map;
> > + };
> > + };
> > +
> > + smem@fa00000 {
>
> This should be smem@fc428000 matching the first reg property. It's weird
> though, because if smem is using a secondary region it will be under the
> SoC node and have a reg property. Otherwise it would be directly under
> the root node and only have a memory-region. It would be nice if we
> could somehow move the rpm message ram (0xfc428000) into the
> reserved-memory node so that we could use memory-region for both regions.
>

I agree, the semantics here became a little bit odd.

I do not think we should list the 0xfc428000 region as a memory-region,
as it's "device memory" and I do like the fact that we don't repeat
ourselves with listing the memory-region as a reg.

Therefor I think this is the least ugly option, but the address in the
name of the node should be updated.

> > + compatible = "qcom,smem";
> > +
> > + memory-region = <&smem_region>;
> > + reg = <0xfc428000 0x4000>;
> > +
> > + hwlocks = <&tcsr_mutex 3>;
> > + };
>

Thanks,
Bjorn