Re: [PATCH v3 1/6] dt-bindings: remoteproc: Add Xilinx RPU subsystem bindings

[Tanmay Shah <tanmay.shah@xilinx.com>]

Hi Mathieu,

Thanks for reviews.

Please find my comments below.

On 2/14/22 10:22 AM, Mathieu Poirier wrote:
> On Thu, Feb 10, 2022 at 03:28:19AM -0800, Tanmay Shah wrote:
>> Xilinx ZynqMP platform has dual-core ARM Cortex R5 Realtime Processing
>> Unit(RPU) subsystem. This patch adds dt-bindings for RPU subsystem (cluster).
>>
>> Signed-off-by: Tanmay Shah<tanmay.shah@xilinx.com>
>> ---
>>
>> Changes in v3:
>>    - None
>>
>>   .../bindings/remoteproc/xlnx,r5f-rproc.yaml   | 139 ++++++++++++++++++
>>   include/dt-bindings/power/xlnx-zynqmp-power.h |   6 +
>>   2 files changed, 145 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/remoteproc/xlnx,r5f-rproc.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/remoteproc/xlnx,r5f-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/xlnx,r5f-rproc.yaml
>> new file mode 100644
>> index 000000000000..d43f0b16ad7f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/remoteproc/xlnx,r5f-rproc.yaml
>> @@ -0,0 +1,139 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id:http://devicetree.org/schemas/remoteproc/xlnx,r5f-rproc.yaml#
>> +$schema:http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Xilinx R5F processor subsystem
>> +
>> +maintainers:
>> +  - Ben Levinsky<ben.levinsky@xilinx.com>
>> +  - Tanmay Shah<tanmay.shah@xilinx.com>
>> +
>> +description: |
>> +  The Xilinx platforms include a pair of Cortex-R5F processors (RPU) for
>> +  real-time processing based on the Cortex-R5F processor core from ARM.
>> +  The Cortex-R5F processor implements the Arm v7-R architecture and includes a
>> +  floating-point unit that implements the Arm VFPv3 instruction set.
>> +
>> +properties:
>> +  compatible:
>> +    const: xlnx,zynqmp-r5fss
>> +
>> +  xlnx,cluster-mode:
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    description: |
>> +      The RPU MPCore can operate in split mode(Dual-processor performance), Safety
>> +      lock-step mode(Both RPU cores execute the same code in lock-step,
>> +      clock-for-clock) or Single CPU mode (RPU core 0 can be held in reset while
>> +      core 1 runs normally). The processor does not support dynamic configuration.
>> +      Switching between modes is only permitted immediately after a processor reset.
>> +      If set to  1 then lockstep mode and if 0 then split mode.
>> +      If set to  2 then single CPU mode. When not defined, default will be lockstep mode.
>> +
>> +  "#address-cells":
>> +    const: 1
>> +
>> +  "#size-cells":
>> +    const: 1
>> +
>> +  reg:
>> +    items:
>> +      - description: RPU subsystem status and control registers
>> +
>> +patternProperties:
>> +  "^r5f-[a-f0-9]+$":
>> +    type: object
>> +    description: |
>> +      The RPU is located in the Low Power Domain of the Processor Subsystem.
>> +      Each processor includes separate L1 instruction and data caches and
>> +      tightly coupled memories (TCM). System memory is cacheable, but the TCM
>> +      memory space is non-cacheable.
>> +
>> +      Each RPU contains one 64KB memory and two 32KB memories that
>> +      are accessed via the TCM A and B port interfaces, for a total of 128KB
>> +      per processor. In lock-step mode, the processor has access to 256KB of
>> +      TCM memory.
>> +
>> +    properties:
>> +      compatible:
>> +        const: xlnx,zynqmp-r5f
>> +
>> +      power-domains:
>> +        description: |
>> +          phandle to a PM domain provider node and an args specifier containing
>> +          the r5f0 and r5f1 node id value.
>> +
>> +      reg:
>> +        items:
>> +          - description: RPU0 and RPU1 control and status registers
>> +
>> +      mboxes:
>> +        items:
>> +          - description: |
>> +              Bi-directional channel to send data to RPU and receive ack from RPU.
>> +              Request and response message buffers are available and each buffer is 32 bytes.
>> +          - description: |
>> +              Bi-directional channel to receive data from RPU and send ack from RPU.
>> +              Request and response message buffers are available and each buffer is 32 bytes.
>> +        minItems: 1
>> +
>> +      mbox-names:
>> +        items:
>> +          - const: tx
>> +          - const: rx
>> +        minItems: 1
>> +
>> +      sram:
>> +        $ref: /schemas/types.yaml#/definitions/phandle-array
>> +        minItems: 1
>> +        description: |
>> +          phandles to one or more reserved on-chip SRAM regions. Other than TCM,
>> +          the RPU can execute instructions and access data from, the OCM memory,
>> +          the main DDR memory, and other system memories.
>> +
>> +          The regions should be defined as child nodes of the respective SRAM
>> +          node, and should be defined as per the generic bindings in,
>> +          Documentation/devicetree/bindings/sram/sram.yaml
>> +
>> +      memory-region:
>> +        $ref: /schemas/types.yaml#/definitions/phandle-array
>> +        description: |
>> +          List of phandles to the reserved memory regions associated with the
>> +          remoteproc device. This is variable and describes the memories shared with
>> +          the remote processor (e.g. remoteproc firmware and carveouts, rpmsg
>> +          vrings, ...). This reserved memory region will be allocated on DDR memory.
>> +          See Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
>>
> Aside from "compatible" and "power-domains", none of the above properties appear
> in the example below, making this patchset harder to review.
>
> I am pretty sure to have commented on this earlier...

In example, I have included only required property nodes.

If you want, I can include other properties as well. However, some of 
the properties needs new bindings for example "sram".

So, I can't include it as I don't know how bindings for them will look like.

In next revision, I can include mboxes, mbox-names and memory-region 
properties. Is that fine?

Also, should I add those nodes in actual device-tree now or later?

For example, mboxes and mbox-names are not needed for driver as of now.

So should I include them in dts now or later when I send rpmsg related 
patches?

> More comments to come later or tomorrow.
>
> Thanks,
> Mathieu
>
>> +    required:
>> +      - compatible
>> +      - power-domains
>> +
>> +    unevaluatedProperties: false
>> +
>> +required:
>> +  - compatible
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    r5fss: r5fss@ff9a0000 {
>> +        compatible = "xlnx,zynqmp-r5fss";
>> +        xlnx,cluster-mode = <1>;
>> +
>> +        #address-cells = <1>;
>> +        #size-cells = <1>;
>> +        reg = <0xff9a0000 0x228>;
>> +
>> +        r5f-0 {
>> +            compatible = "xlnx,zynqmp-r5f";
>> +            power-domains = <&zynqmp_firmware 0x7>;
>> +        };
>> +
>> +        r5f-1 {
>> +            compatible = "xlnx,zynqmp-r5f";
>> +            power-domains = <&zynqmp_firmware 0x8>;
>> +        };
>> +    };
>> +...
>> diff --git a/include/dt-bindings/power/xlnx-zynqmp-power.h b/include/dt-bindings/power/xlnx-zynqmp-power.h
>> index 0d9a412fd5e0..618024cbb20d 100644
>> --- a/include/dt-bindings/power/xlnx-zynqmp-power.h
>> +++ b/include/dt-bindings/power/xlnx-zynqmp-power.h
>> @@ -6,6 +6,12 @@
>>   #ifndef _DT_BINDINGS_ZYNQMP_POWER_H
>>   #define _DT_BINDINGS_ZYNQMP_POWER_H
>>   
>> +#define		PD_RPU_0	7
>> +#define		PD_RPU_1	8
>> +#define		PD_R5_0_ATCM	15
>> +#define		PD_R5_0_BTCM	16
>> +#define		PD_R5_1_ATCM	17
>> +#define		PD_R5_1_BTCM	18
>>   #define		PD_USB_0	22
>>   #define		PD_USB_1	23
>>   #define		PD_TTC_0	24
>> -- 
>> 2.25.1
>>