On Mon, Feb 05 2018 at 22:11 +0000, Bjorn Andersson wrote:
On Tue 30 Jan 08:17 PST 2018, Lina Iyer wrote:
On Mon, Jan 29 2018 at 19:08 +0000, Rob Herring wrote:
> On Thu, Jan 18, 2018 at 03:28:02PM -0700, Lina Iyer wrote:
[..]
> > diff --git a/Documentation/devicetree/bindings/arm/msm/cmd-db.txt b/Documentation/devicetree/bindings/arm/msm/cmd-db.txt
[..]
> > +Command DB is a database that provides a mapping between resource key and the
> > +resource address for a system resource managed by a remote processor. The data
> > +is stored in a shared memory region and is loaded by the remote processor.
>
> Is said shared memory described in DT. If so, this should be a child
> node. Only 8 bytes seems kind of fine grained for putting in DT when it
> could be implied by the parent shared memory node.
>
I dont believe this memory will be described in DT for this chipset.
Will ask internally.
Well, these things goes two ways...
> > +
> > +Some of the Qualcomm Technologies Inc SoC's have hardware accelerators for
> > +controlling shared resources. Depending on the board configuration the shared
> > +resource properties may change. These properties are dynamically probed by the
> > +remote processor and made available in the shared memory.
>
> The table may change, but does the presence of it or shared memory
> location (of the pointer) change?
>
The location may change between different SoCs, but will be present in
all chipsets of this architecture.
Where is the actual DB located? System RAM or is it some special
device-memory?
It's carved out of system memory and is access protected. Not a device
memory.
-- Lina
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