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Subject: Re: [PATCH v4 22/37] dt-bindings: host1x: Document new interconnect
 properties
To:     Rob Herring <robh@kernel.org>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Georgi Djakov <georgi.djakov@linaro.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Mikko Perttunen <cyndis@kapsi.fi>,
        =?UTF-8?B?QXJ0dXIgxZp3aWdvxYQ=?= <a.swigon@samsung.com>,
        linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        devicetree@vger.kernel.org
References: <20200609131404.17523-1-digetx@gmail.com>
 <20200609131404.17523-23-digetx@gmail.com> <20200617213726.GA2837398@bogus>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <5303317a-2cb6-d7a8-361a-30867fc6eab7@gmail.com>
Date:   Thu, 18 Jun 2020 00:44:47 +0300
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18.06.2020 00:37, Rob Herring пишет:
> On Tue, Jun 09, 2020 at 04:13:49PM +0300, Dmitry Osipenko wrote:
>> Most of Host1x devices have at least one memory client. These clients
>> are directly connected to the memory controller. The new interconnect
>> properties represent the memory client's connection to the memory
>> controller.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  .../display/tegra/nvidia,tegra20-host1x.txt   | 68 +++++++++++++++++++
>>  1 file changed, 68 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
>> index 47319214b5f6..ab4fbee7bccf 100644
>> --- a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
>> +++ b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
>> @@ -20,6 +20,10 @@ Required properties:
>>  - reset-names: Must include the following entries:
>>    - host1x
>>  
>> +Each host1x client module having to perform DMA through the Memory Controller
>> +should have the interconnect endpoints set to the Memory Client and External
>> +Memory respectively.
>> +
>>  The host1x top-level node defines a number of children, each representing one
>>  of the following host1x client modules:
>>  
>> @@ -36,6 +40,12 @@ of the following host1x client modules:
>>    - reset-names: Must include the following entries:
>>      - mpe
>>  
>> +  Optional properties:
>> +  - interconnects: Must contain entry for the MPE memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>> +
>>  - vi: video input
>>  
>>    Required properties:
>> @@ -65,6 +75,12 @@ of the following host1x client modules:
>>        - power-domains: Must include sor powergate node as csicil is in
>>          SOR partition.
>>  
>> +  Optional properties:
>> +  - interconnects: Must contain entry for the VI memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>> +
>>  - epp: encoder pre-processor
>>  
>>    Required properties:
>> @@ -78,6 +94,12 @@ of the following host1x client modules:
>>    - reset-names: Must include the following entries:
>>      - epp
>>  
>> +  Optional properties:
>> +  - interconnects: Must contain entry for the EPP memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>> +
>>  - isp: image signal processor
>>  
>>    Required properties:
>> @@ -91,6 +113,12 @@ of the following host1x client modules:
>>    - reset-names: Must include the following entries:
>>      - isp
>>  
>> +  Optional properties:
>> +  - interconnects: Must contain entry for the ISP memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>> +
>>  - gr2d: 2D graphics engine
>>  
>>    Required properties:
>> @@ -104,6 +132,12 @@ of the following host1x client modules:
>>    - reset-names: Must include the following entries:
>>      - 2d
>>  
>> +  Optional properties:
>> +  - interconnects: Must contain entry for the GR2D memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>> +
>>  - gr3d: 3D graphics engine
>>  
>>    Required properties:
>> @@ -122,6 +156,12 @@ of the following host1x client modules:
>>      - 3d
>>      - 3d2 (Only required on SoCs with two 3D clocks)
>>  
>> +  Optional properties:
>> +  - interconnects: Must contain entry for the GR3D memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>> +
>>  - dc: display controller
>>  
>>    Required properties:
>> @@ -149,6 +189,10 @@ of the following host1x client modules:
>>    - nvidia,hpd-gpio: specifies a GPIO used for hotplug detection
>>    - nvidia,edid: supplies a binary EDID blob
>>    - nvidia,panel: phandle of a display panel
>> +  - interconnects: Must contain entry for the DC memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>>  
>>  - hdmi: High Definition Multimedia Interface
>>  
>> @@ -297,6 +341,12 @@ of the following host1x client modules:
>>    - reset-names: Must include the following entries:
>>      - vic
>>  
>> +  Optional properties:
>> +  - interconnects: Must contain entry for the VIC memory clients.
>> +  - interconnect-names: Must include name of the interconnect path for each
>> +    interconnect entry. Consult TRM documentation for information about
>> +    available memory clients, see MEMORY CONTROLLER section.
>> +
>>  Example:
>>  
>>  / {
>> @@ -410,6 +460,15 @@ Example:
>>  			resets = <&tegra_car 27>;
>>  			reset-names = "dc";
>>  
>> +			interconnects = <&mc TEGRA20_MC_DISPLAY0A &emc>,
>> +					<&mc TEGRA20_MC_DISPLAY0B &emc>,
>> +					<&mc TEGRA20_MC_DISPLAY0C &emc>,
>> +					<&mc TEGRA20_MC_DISPLAY1B &emc>;
> 
> This looks odd or wrong. Each entry has 2 phandles? 

Each entry defines interconnect path, where MC is the start of the path
and EMC is the end. So yes, 2 phandles for each path.

Please see arm/boot/dts/qcom-msm8974.dtsi for another example [1].

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/qcom-msm8974.dtsi?h=v5.8-rc1#n1448