lkml.org 
[lkml]   [2018]   [Feb]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v2 2/2] dt-bindings: introduce Command DB for QCOM SoCs
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>;
>> + };

\
 
 \ /
  Last update: 2018-02-15 19:47    [W:0.296 / U:0.840 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site