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

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Mon, Feb 21, 2022 at 05:58:15PM -0800, Tanmay Shah wrote:
> 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.
> 

I'm fine with that part.

> 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?

Include in the example the properties currently supported by the driver.  Not
all of them have to be in the DTS though.

> 
> > 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
> > >