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@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx Signed-off-by: Mahesh Sivasubramanian <msivasub@xxxxxxxxxxxxxx> Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx> --- .../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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