Messages in this thread Patch in this message | | | Date | Thu, 15 Feb 2018 18:46:17 +0000 | From | Lina Iyer <> | Subject | Re: [PATCH v2 2/2] dt-bindings: introduce Command DB for QCOM SoCs |
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On Wed, Feb 14 2018 at 19:34 +0000, Bjorn Andersson wrote: >On Thu 08 Feb 11:51 PST 2018, Lina Iyer wrote: > >> From: Mahesh Sivasubramanian <msivasub@codeaurora.org> >> >> Command DB provides information on shared resources like clocks, >> regulators etc., probed at boot by the remote subsytem and made >> available in shared memory. >> >> Cc: devicetree@vger.kernel.org >> Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org> >> Signed-off-by: Lina Iyer <ilina@codeaurora.org> >> --- >> .../devicetree/bindings/arm/msm/cmd-db.txt | 38 ++++++++++++++++++++++ >> 1 file changed, 38 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/arm/msm/cmd-db.txt >> >> diff --git a/Documentation/devicetree/bindings/arm/msm/cmd-db.txt b/Documentation/devicetree/bindings/arm/msm/cmd-db.txt >> new file mode 100644 >> index 000000000000..e21666e40ebf >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/arm/msm/cmd-db.txt >> @@ -0,0 +1,38 @@ >> +Command DB >> +--------- >> + >> +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. >> + >> +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 devicetree representation of the command DB driver should be: >> + >> +PROPERTIES: >> +- compatible: >> + Usage: required >> + Value type: <string> >> + Definition: Should be "qcom,cmd-db" >> + >> +- memory-region: >> + Usage: required >> + Value type: <phandle> >> + Definition: The phandle to the reserved memory region. >> + >> +Example: >> + >> + reserved-memory { >> + [...] >> + cmd_db_mem: qcom,cmd-db@c3f000c { >> + reg = <0x0 0xc3f000c 0x0 0x8>; >I was hoping that we can describe the actual memory here, as I got the >impression that it will also be a chunk of memory carved out from System >RAM. > Yes, it can be described. But, the location should always be read from the address above. Generally, the CMD DB memory would not change, but it is not always guaranteed.
>If not it would seem unlikely that there's a 8 byte carveout in the >middle of DDR, what else is here? > >> + }; >> + }; >> + >> + qcom,cmd-db@c3f000c { >> + compatible = "qcom,cmd-db"; > >Add "qcom,cmd-db" to "reserved_mem_matches" in drivers/of/platform.c, >use of_reserved_mem_lookup(pdev->dev.of_node) to get the reserved_mem >and you can just put the compatible directly on the reserved-memory >node. > >That way you don't need this separate node that doesn't really represent >anything. > Oh okay. I can take care of that.
Thanks, Lina >> + memory-region = <&cmd_db_mem>; >> + };
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