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From:   Rob Herring <robh@kernel.org>
Date:   Wed, 7 Mar 2018 19:24:52 -0600
Message-ID: <CAL_JsqLNxsVaMoefYfLi7ow8BjLkipNJwjvXgpEuXZZF8PT6+A@mail.gmail.com>
Subject: Re: [PATCHv2 4/7] dt-bindings: fpga: add Stratix10 SoC FPGA manager binding
To:     Alan Tull <atull@kernel.org>
Cc:     Richard Gong <richard.gong@linux.intel.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Dinh Nguyen <dinguyen@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Moritz Fischer <mdf@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, linux-fpga@vger.kernel.org,
        Yves Vandervennet <yves.vandervennet@linux.intel.com>
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On Wed, Mar 7, 2018 at 4:20 PM, Alan Tull <atull@kernel.org> wrote:
> On Wed, Mar 7, 2018 at 1:47 PM, Rob Herring <robh@kernel.org> wrote:
>> On Thu, Mar 01, 2018 at 06:19:32PM -0600, richard.gong@linux.intel.com wrote:
>>> From: Alan Tull <atull@kernel.org>
>>>
>>> Add a Device Tree binding for the Intel Stratix10 SoC FPGA manager.
>>>
>>> Signed-off-by: Alan Tull <atull@kernel.org>
>>> ---
>>> v2: this patch is added in patch set version 2
>>> ---
>>>  .../devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt  | 10 ++++++++++
>>>  1 file changed, 10 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt b/Documentation/devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt
>>> new file mode 100644
>>> index 0000000..78de689
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt
>>> @@ -0,0 +1,10 @@
>>> +Intel Stratix10 SoC FPGA Manager
>>> +
>>> +Required properties:
>>> +- compatible : should contain "intel,stratix10-soc-fpga-mgr"
>>> +
>>> +Example:
>>> +
>>> +     fpga_mgr: fpga-mgr@0 {
>>> +             compatible = "intel,stratix10-soc-fpga-mgr";
>>
>> No reg or anything else? Is that because it all goes thru the service
>> layer firmware?
>
> Yes.
>
> There will be a few more clients of the service layer: QSPI, Crypto
> and warm reset.
>
>> Just get the service layer driver to instantiate a
>> device for this driver or get rid of the 2 layers if that's all the
>> firmware interface does. DT is not a Linux driver instantiation
>> mechanism.
>
> Right, this should be describing hardware.
>
> I could add this to the service layer binding:
>
> firmware {
>         svc {
>                 compatible = "intel,stratix10-svc";
>                 method = "smc";
>                 memory-region = <&service_reserved>;
>                 fpga-mgr {
>                         compatible = "intel,stratix10-soc-fpga-mgr";

Still, why do you need this node? If you don't have any other cross
tree connections, then the service layer can instantiate the
device(s).

OTOH, QSPI would need a node because you'll need to describe its bus.

Rob