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Message-ID: <1856eb4ef9c9b448.51cf78412ad49c56.737f9c77b35de27d@Jude-Air.local>
Date: Wed, 30 Jul 2025 03:57:09 +0000
From: "Junhui Liu" <junhui.liu@...moral.tech>
To: "Inochi Amaoto" <inochiama@...il.com>,
"Bjorn Andersson" <andersson@...nel.org>,
"Mathieu Poirier" <mathieu.poirier@...aro.org>,
"Rob Herring" <robh@...nel.org>,
"Krzysztof Kozlowski" <krzk+dt@...nel.org>,
"Conor Dooley" <conor+dt@...nel.org>,
"Chen Wang" <unicorn_wang@...look.com>,
"Philipp Zabel" <p.zabel@...gutronix.de>,
"Paul Walmsley" <paul.walmsley@...ive.com>,
"Palmer Dabbelt" <palmer@...belt.com>, "Albert Ou" <aou@...s.berkeley.edu>,
"Alexandre Ghiti" <alex@...ti.fr>
Cc: <linux-remoteproc@...r.kernel.org>, <devicetree@...r.kernel.org>,
<sophgo@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
<linux-riscv@...ts.infradead.org>
Subject: Re: [PATCH v2 1/2] dt-bindings: remoteproc: Add C906L rproc for Sophgo
CV1800B SoC
On 29/07/2025 16:31, Inochi Amaoto wrote:
> On Mon, Jul 28, 2025 at 07:03:23PM +0800, Junhui Liu wrote:
>> Add C906L remote processor for CV1800B SoC, which is an asymmetric
>> processor typically running RTOS.
>>
>> Signed-off-by: Junhui Liu <junhui.liu@...moral.tech>
>> ---
>> .../bindings/remoteproc/sophgo,cv1800b-c906l.yaml | 79 ++++++++++++++++++++++
>> 1 file changed, 79 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/remoteproc/sophgo,cv1800b-c906l.yaml b/Documentation/devicetree/bindings/remoteproc/sophgo,cv1800b-c906l.yaml
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..2061c2fd6ba343c09b1a91700ea4a695d2b57f81
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/remoteproc/sophgo,cv1800b-c906l.yaml
>> @@ -0,0 +1,79 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/remoteproc/sophgo,cv1800b-c906l.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Sophgo C906L remote processor controller for CV1800B SoC
>> +
>> +maintainers:
>> + - Junhui Liu <junhui.liu@...moral.tech>
>> +
>> +description:
>> + Document the bindings for the C906L remoteproc component that loads and boots
>> + firmwares on the CV1800B SoC.
>> +
>> +properties:
>> + compatible:
>> + const: sophgo,cv1800b-c906l
>> +
>> + firmware-name:
>> + maxItems: 1
>> +
>> + mbox-names:
>> + items:
>> + - const: tx
>> + - const: rx
>> +
>> + mboxes:
>> + description:
>> + This property is required only if the rpmsg/virtio functionality is used.
>> + (see mailbox/sophgo,cv1800b-mailbox.yaml)
>> + items:
>> + - description: mailbox channel to send data to C906L
>> + - description: mailbox channel to receive data from C906L
>> +
>> + memory-region:
>> + description:
>> + List of phandles to reserved memory regions used by the remote processor.
>> + The first region is required and provides the firmware region for the
>> + remote processor. The following regions (vdev buffer, vrings) are optional
>> + and are only required if rpmsg/virtio functionality is used.
>> + minItems: 1
>> + items:
>> + - description: firmware region
>> + - description: vdev buffer
>> + - description: vring0
>> + - description: vring1
>> + additionalItems: true
>> +
>
> Why not allocating these region dynamicly? I do not think firware is
> always avaible before staring. Allowing dynamic firmware give us max
> flexiblity.
I'm afraid it's not easy to do this.
For firmware region, the RTOS firmware usually needs a physical address
to link to, and I have researched and tested two RTOS (RT-Thread and
Zephyr) on the C906L, both of them do not support position-independent
execution or runtime relocation. Therefore, a reserved memory region is
needed to provide a fixed physical address for the RTOS firmware.
(In fact, there is already a reserved memory region for the C906L in
cv1800b-milkv-duo.dts)
For virtio-related regions, the RTOS firmware also needs to know the
shared memory regions for communications at compile time.
So, reserving memory through DT is necessary for now.
>
> Regards,
> Inochi
--
Best regards,
Junhui Liu
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