Message-ID: <15374680-b9bc-a7a2-2723-570294456d24@linaro.org>
Date:   Wed, 8 Mar 2023 09:41:23 +0100
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Subject: Re: [PATCH v3 1/3] dt-bindings: remoteproc: k3-m4f: Add bindings for
 K3 AM64x SoCs
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To:     Martyn Welch <martyn.welch@collabora.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Hari Nagalla <hnagalla@ti.com>
Cc:     kernel@collabora.com, linux-remoteproc@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230302171450.1598576-1-martyn.welch@collabora.com>
 <20230302171450.1598576-2-martyn.welch@collabora.com>
 <5c9130de-5092-9446-6e00-d86de7dcd6b4@linaro.org>
 <c2bebcbf9d463d656ae69d489e0e5a88f2540c2e.camel@collabora.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <c2bebcbf9d463d656ae69d489e0e5a88f2540c2e.camel@collabora.com>
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On 07/03/2023 19:26, Martyn Welch wrote:
> On Fri, 2023-03-03 at 09:06 +0100, Krzysztof Kozlowski wrote:
>> On 02/03/2023 18:14, Martyn Welch wrote:
>>
>>> +
>>> +  mboxes:
>>> +    description: |
>>> +      OMAP Mailbox specifier denoting the sub-mailbox, to be used
>>> for
>>
>> OMAP?
>>
> 
> This device uses a mailbox compatible with the OMAP Mailbox, as defined
> in Documentation/devicetree/bindings/mailbox/ti,omap-mailbox.yaml.
> 
> I note that documents title reads "TI OMAP2+ and K3 Mailbox devices".
> I'll drop the "OMAP" here.
> 
>>> +      communication with the remote processor. This property
>>> should match
>>> +      with the sub-mailbox node used in the firmware image.
>>> +    maxItems: 1
>>> +
>>> +  memory-region:
>>> +    description: |
>>> +      phandle to the reserved memory nodes to be associated with
>>> the
>>> +      remoteproc device. There should be at least two reserved
>>> memory nodes
>>> +      defined. 
>>
>> Don't repeat constraints in free form text.
>>
>>> The reserved memory nodes should be carveout nodes, and
>>> +      should be defined with a "no-map" property as per the
>>> bindings in
>>> +      Documentation/devicetree/bindings/reserved-memory/reserved-
>>> memory.yaml
>>> +    minItems: 2
>>> +    maxItems: 8
>>> +    items:
>>> +      - description: region used for dynamic DMA allocations like
>>> vrings and
>>> +                     vring buffers
>>> +      - description: region reserved for firmware image sections
>>> +    additionalItems: true
>>
>> And what is the purpose of the rest of reserved nodes?
>>
> 
> Up to 8 regions can be specified with their purpose determined by the
> firmware running on the M4F core. The suggestion (and the
> implementation in the example firmware) is to use the first 2 regions
> as defined above for remoteproc with the others available to be used
> for other purposes if necessary. The address translation module used
> can cope with up to 8 regions.

Then mention the rest is just dedicated to the firmware and it's purpose
depends on the firmware.

Best regards,
Krzysztof