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From:   Alan Tull <atull@kernel.org>
Date:   Thu, 8 Mar 2018 09:32:44 -0600
Message-ID: <CANk1AXQRsAyFOGnUGcdWa0g0SdWu1PD=osYazj3nXJVq8ErABQ@mail.gmail.com>
Subject: Re: [PATCHv2 4/7] dt-bindings: fpga: add Stratix10 SoC FPGA manager binding
To:     Rob Herring <robh@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 7:24 PM, Rob Herring <robh@kernel.org> wrote:
> 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 {

Actually, add a label.

                  fpga_mgr: 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).

It's used for the FPGA region to know what mgr can program the region.

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