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Subject: Re: [PATCH 3/7] dt-bindings: remoteproc: Add bindings for R5F
 subsystem on TI K3 SoCs
To:     Rob Herring <robh+dt@kernel.org>
CC:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Lokesh Vutla <lokeshvutla@ti.com>,
        "open list:REMOTE PROCESSOR (REMOTEPROC) SUBSYSTEM" 
        <linux-remoteproc@vger.kernel.org>, <devicetree@vger.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <20200324201819.23095-1-s-anna@ti.com>
 <20200324201819.23095-4-s-anna@ti.com>
 <CAL_JsqKpC=W-y3OdeqSROhiKLbQKf3sGyCXzQH__Wr-O=QS4Tg@mail.gmail.com>
From:   Suman Anna <s-anna@ti.com>
Message-ID: <30cb4bee-fe79-8683-8225-fad174e0d630@ti.com>
Date:   Wed, 8 Apr 2020 19:02:06 -0500
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Hi Rob,

On 3/26/20 11:53 AM, Rob Herring wrote:
> On Tue, Mar 24, 2020 at 2:18 PM Suman Anna <s-anna@ti.com> wrote:
>>
>> The Texas Instruments K3 family of SoCs have one or more dual-core
>> Arm Cortex R5F processor subsystems/clusters (R5FSS). The clusters
>> can be split between multiple voltage domains as well. Add the device
>> tree bindings document for these R5F subsystem devices. These R5F
>> processors do not have an MMU, and so require fixed memory carveout
>> regions matching the firmware image addresses. The nodes require more
>> than one memory region, with the first memory region used for DMA
>> allocations at runtime. The remaining memory regions are reserved
>> and are used for the loading and running of the R5F remote processors.
>> The R5F processors can also optionally use any internal on-chip SRAM
>> memories either for executing code or using it as fast-access data.
> 
> I'm inclined to say the system DT stuff should be sorted out before
> accepting this. Is the system DT stuff going to be useful for your R5
> cores? Do you really want to be stuck with this binding?

Hmm, I am not dependent on System DT and prefer to be not gated by that.
This is still all from the Linux host perspective, and we don't have any
plans to use DT on the firmware-side.

> 
>> The added example illustrates the DT nodes for the single R5FSS device
>> present on K3 AM65x family of SoCs.
>>
>> Signed-off-by: Suman Anna <s-anna@ti.com>
>> ---
>> Hi Rob,
>>
>> The dt_bindings_check seems to throw couple of warnings around the
>> usage of ranges because the tooling is adding the #address-cells
>> and #size-cells of 1 by default, whereas our actual code uses 2.
> 
> Then change the default by specifying what you want. Or change the
> example to be 1 cell. It is *just* an example.

OK, was using the actual dts nodes as how they would be added in our dts
files. The only way to get rid of the warnings is to use 1 cell. I can
do that for the R5F bindings, but cannot really do that for the DSPs
since the addresses need 2 cells.

> 
>> No issues are found with dtbs_check.
> 
> I doubt that if your dts matches the example.

The top-level cells value is 2 in our dts files (See either of
arm64/dts/ti/k3-am65.dtsi or k3-j721e.dtsi).

> 
>>
>> regards
>> Suman
>>
>>  .../bindings/remoteproc/ti,k3-r5f-rproc.yaml  | 338 ++++++++++++++++++
>>  1 file changed, 338 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/remoteproc/ti,k3-r5f-rproc.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/remoteproc/ti,k3-r5f-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/ti,k3-r5f-rproc.yaml
>> new file mode 100644
>> index 000000000000..bbfc1e6ae884
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/remoteproc/ti,k3-r5f-rproc.yaml
>> @@ -0,0 +1,338 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/remoteproc/ti,k3-r5f-rproc.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: TI K3 R5F processor subsystems
>> +
>> +maintainers:
>> +  - Suman Anna <s-anna@ti.com>
>> +
>> +description: |
>> +  The TI K3 family of SoCs usually have one or more dual-core Arm Cortex R5F
>> +  processor subsystems/clusters (R5FSS). The dual core cluster can be used
>> +  either in a LockStep mode providing safety/fault tolerance features or in a
>> +  Split mode providing two individual compute cores for doubling the compute
>> +  capacity. These are used together with other processors present on the SoC
>> +  to achieve various system level goals.
>> +
>> +  Each Dual-Core R5F sub-system is represented as a single DTS node
>> +  representing the cluster, with a pair of child DT nodes representing
>> +  the individual R5F cores. Each node has a number of required or optional
>> +  properties that enable the OS running on the host processor to perform
>> +  the device management of the remote processor and to communicate with the
>> +  remote processor.
>> +
>> +# Required properties:
>> +# --------------------
>> +# The following are the mandatory properties:
>> +
>> +properties:
>> +  $nodename:
>> +    pattern: "^r5fss(@.*)?"
>> +
>> +  compatible:
>> +    enum:
>> +      - ti,am654-r5fss
>> +      - ti,j721e-r5fss
>> +
>> +  power-domains:
>> +    description: |
>> +      Should contain a phandle to a PM domain provider node and an args
>> +      specifier containing the R5FSS device id value. This property is
>> +      as per the binding,
>> +      Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
> 
> What implementation of power domains is used is outside the scope of
> this binding. I'd just drop the whole description as it is pretty
> generic.

OK.

> 
>> +    maxItems: 1
>> +
>> +  "#address-cells":
>> +    const: 1
>> +
>> +  "#size-cells":
>> +    const: 1
>> +
>> +  ranges:
>> +    description: |
>> +      Standard ranges definition providing address translations for
>> +      local R5F TCM address spaces to bus addresses.
>> +
>> +# Optional properties:
>> +# --------------------
>> +
>> +  lockstep-mode:
> 
> Needs a vendor prefix.

Yep, will fix this one and all the others below.

> 
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    enum: [0, 1]
>> +    description: |
>> +      Configuration Mode for the Dual R5F cores within the R5F
>> +      cluster. Should be either a value of 1 (LockStep mode) or
>> +      0 (Split mode), default is LockStep mode if omitted.
>> +
>> +# R5F Processor Child Nodes:
>> +# ==========================
>> +
>> +patternProperties:
>> +  "^r5f@[a-f0-9]+$":
>> +    type: object
>> +    description: |
>> +        The R5F Sub-System device node should define two R5F child nodes, each
>> +        node representing a TI instantiation of the Arm Cortex R5F core. There
>> +        are some specific integration differences for the IP like the usage of
>> +        a Region Address Translator (RAT) for translating the larger SoC bus
>> +        addresses into a 32-bit address space for the processor.
>> +
>> +# Required properties:
>> +# --------------------
>> +# The following are the mandatory properties:
>> +
>> +    properties:
>> +      compatible:
>> +        enum:
>> +          - ti,am654-r5f
>> +          - ti,j721e-r5f
>> +
>> +      reg:
>> +        description: |
>> +          Should contain an entry for each value in 'reg-names'.
>> +          Each entry should have the memory region's start address
>> +          and the size of the region, the representation matching
>> +          the parent node's '#address-cells' and '#size-cells' values.
> 
> That's every 'reg' property.
> 
>> +        maxItems: 2
> 
> You need to define what each one is:
> 
> items:
>   - description: ...
>   - description: ...

OK, will fix.

> 
>> +
>> +      reg-names:
>> +        description: |
>> +          Should contain strings with the names of the specific internal
>> +          internal memory regions, and should be defined in this order
>> +        maxItems: 2
>> +        items:
>> +          - const: atcm
>> +          - const: btcm
>> +
>> +      ti,sci:
>> +        $ref: /schemas/types.yaml#/definitions/phandle
>> +        description:
>> +          Should be a phandle to the TI-SCI System Controller node
>> +
>> +      ti,sci-dev-id:
>> +        $ref: /schemas/types.yaml#/definitions/uint32
>> +        description: |
>> +          Should contain the TI-SCI device id corresponding to the R5F core.
>> +          Please refer to the corresponding System Controller documentation
>> +          for valid values for the R5F cores.
>> +
>> +      ti,sci-proc-ids:
>> +        description: Should contain a single tuple of <proc_id host_id>.
>> +        allOf:
>> +          - $ref: /schemas/types.yaml#/definitions/uint32-matrix
> 
> Sounds more like an array.

OK, I can modify this. Went with this originally to reflect the tuple,
but guess both translate similarly for my usage.

> 
>> +          - maxItems: 1
>> +            items:
>> +              items:
>> +                - description: TI-SCI processor id for the R5F core device
>> +                - description: TI-SCI host id to which processor control
>> +                               ownership should be transferred to
>> +
>> +      resets:
>> +        description: |
>> +          Should contain the phandle to the reset controller node
>> +          managing the resets for this device, and a reset
>> +          specifier. Please refer to the following reset bindings
>> +          for the reset argument specifier,
>> +          Documentation/devicetree/bindings/reset/ti,sci-reset.txt
>> +            for AM65x and J721E SoCs
> 
> Drop. How many resets (maxItems or items list)?

Yeah, this is 1, will update. Do you want me to drop just the specifier
link or the entire description?

> 
>> +
>> +      firmware-name:
>> +        description: |
>> +          Should contain the name of the default firmware image
>> +          file located on the firmware search path
>> +
>> +# The following properties are mandatory for R5F Core0 in both LockStep and Split
>> +# modes, and are mandatory for R5F Core1 _only_ in Split mode. They are unused for
>> +# R5F Core1 in LockStep mode:
>> +
>> +      mboxes:
>> +        description: |
>> +          OMAP Mailbox specifier denoting the sub-mailbox, to be used for
>> +          communication with the remote processor. This property should match
>> +          with the sub-mailbox node used in the firmware image. The specifier
>> +          format is as per the bindings,
>> +          Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
> 
> How many?

OK, will fix.

> 
>> +
>> +      memory-region:
>> +        minItems: 2
>> +        description: |
>> +          phandle to the reserved memory nodes to be associated with the remoteproc
>> +          device. There should be atleast two reserved memory nodes defined - the
> 
> What's the max number? As is, it will be 2.

Aah, I misinterpreted that not having would be open-ended. OK, I will
have to give an arbitrary number here (maybe 4 or 8). Can we update this
later on if a usecase really needs more?

> 
>> +          first one would be used for dynamic DMA allocations like vrings and vring
>> +          buffers, and the remaining ones used for the firmware image sections. The
>> +          reserved memory nodes should be carveout nodes, and should be defined as
>> +          per the bindings in
>> +          Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
>> +
>> +# Optional properties:
>> +# --------------------
>> +# The following properties are optional properties for each of the R5F cores:
>> +
>> +      atcm-enable:
> 
> Vendor prefix needed.
> 
>> +        $ref: /schemas/types.yaml#/definitions/uint32
>> +        enum: [0, 1]
>> +        description: |
>> +          R5F core configuration mode dictating if ATCM should be enabled. R5F
>> +          view of ATCM dictated by loczrama property. Should be either a value
>> +          of 1 (enabled) or 0 (disabled), default is disabled if omitted.
>> +
>> +      btcm-enable:
> 
> ditto
> 
>> +        $ref: /schemas/types.yaml#/definitions/uint32
>> +        enum: [0, 1]
>> +        description: |
>> +          R5F core configuration mode dictating if BTCM should be enabled. R5F
>> +          view of BTCM dictated by loczrama property. Should be either a value
>> +          of 1 (enabled) or 0 (disabled), default is enabled if omitted.
>> +
>> +      loczrama:
> 
> ditto
> 
>> +        $ref: /schemas/types.yaml#/definitions/uint32
>> +        enum: [0, 1]
>> +        description: |
>> +          R5F core configuration mode dictating which TCM should appear at
>> +          address 0 (from core's view). Should be either a value of 1 (ATCM
>> +          at 0x0) or 0 (BTCM at 0x0), default value is 1 if omitted.
> 
> I can't decipher how you came up with 'loczrama' based on the description.

That's actually the signal name from the Arm R5 specs.

> 
>> +
>> +      sram:
>> +        $ref: /schemas/types.yaml#/definitions/phandle-array
>> +        minItems: 1
>> +        description: |
>> +          pHandles to one or more reserved on-chip SRAM region. 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
>> +
>> +    required:
>> +     - compatible
>> +     - reg
>> +     - reg-names
>> +     - ti,sci
>> +     - ti,sci-dev-id
>> +     - ti,sci-proc-ids
>> +     - resets
>> +     - firmware-name
>> +
>> +    additionalProperties: false
>> +
>> +required:
>> + - compatible
>> + - power-domains
>> + - "#address-cells"
>> + - "#size-cells"
>> + - ranges
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +
>> +    //Example: AM654 SoC
>> +    /* R5F DDR Carveout reserved memory nodes */
>> +    reserved-memory {
>> +        #address-cells = <2>;
>> +        #size-cells = <2>;
>> +        ranges;
>> +
>> +        mcu_r5fss0_core1_dma_memory_region: r5f-dma-memory@9b000000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9b000000 0x00 0x100000>;
>> +            no-map;
>> +        };
>> +
>> +        mcu_r5fss0_core1_memory_region: r5f-memory@9b100000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9b100000 0x00 0xf00000>;
>> +            no-map;
>> +        };
>> +
>> +        mcu_r5fss0_core0_dma_memory_region: r5f-dma-memory@9c000000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9c000000 0x00 0x100000>;
>> +            no-map;
>> +        };
>> +
>> +        mcu_r5fss0_core0_memory_region: r5f-memory@9c100000 {
>> +            compatible = "shared-dma-pool";
>> +            reg = <0x00 0x9c100000 0x00 0x700000>;
>> +            no-map;
>> +        };
>> +    };
>> +
>> +    cbass_main: interconnect@100000 {
> 
> bus@...

Yeah, will update the example to use bus. The DTS nodes in the kernel
are already using the interconnect name.

> 
> Doesn't look like the right address either.

Yeah, I skipped the actual first entry from the ranges, and only
mentioned the ones that I am using in the nodes. Will fix this.

> 
>> +        compatible = "simple-bus";
>> +        #address-cells = <2>;
>> +        #size-cells = <2>;
>> +        ranges = <0x00 0x41000000 0x00 0x41000000 0x00 0x00020000>,
>> +                 <0x00 0x41400000 0x00 0x41400000 0x00 0x00020000>,
>> +                 <0x00 0x41c00000 0x00 0x41c00000 0x00 0x00080000>;
>> +
>> +        cbass_mcu: interconnect@28380000 {
> 
> Doesn't look like the right address.

Same as above.

> 
>> +            compatible = "simple-bus";
>> +            #address-cells = <2>;
>> +            #size-cells = <2>;
>> +            ranges = <0x00 0x41000000 0x00 0x41000000 0x00 0x00020000>, /* MCU R5F Core0 */
>> +                     <0x00 0x41400000 0x00 0x41400000 0x00 0x00020000>, /* MCU R5F Core1 */
>> +                     <0x00 0x41c00000 0x00 0x41c00000 0x00 0x00080000>; /* MCU SRAM */
>> +
>> +            /* MCU domain SRAM node */
>> +            mcu_ram: mcu-ram@41c00000 {
> 
> I would omit this node from the example. Nothing special here really.

Showcasing the optional sram property usage from the mcu_r5f0 node.

regards
Suman

> 
>> +                compatible = "mmio-sram";
>> +                reg = <0x00 0x41c00000 0x00 0x80000>;
>> +                ranges = <0x0 0x00 0x41c00000 0x80000>;
>> +                #address-cells = <1>;
>> +                #size-cells = <1>;
>> +
>> +                mcu_r5fss0_core0_sram: r5f-sram@0 {
>> +                    reg = <0x0 0x40000>;
>> +                };
>> +            };
>> +
>> +            /* AM65x MCU R5FSS node */
>> +            mcu_r5fss0: r5fss@41000000 {
>> +                compatible = "ti,am654-r5fss";
>> +                power-domains = <&k3_pds 129>;
>> +                lockstep-mode = <1>;
>> +                #address-cells = <1>;
>> +                #size-cells = <1>;
>> +                ranges = <0x41000000 0x00 0x41000000 0x20000>,
>> +                         <0x41400000 0x00 0x41400000 0x20000>;
>> +
>> +                mcu_r5f0: r5f@41000000 {
>> +                    compatible = "ti,am654-r5f";
>> +                    reg = <0x41000000 0x00008000>,
>> +                          <0x41010000 0x00008000>;
>> +                    reg-names = "atcm", "btcm";
>> +                    ti,sci = <&dmsc>;
>> +                    ti,sci-dev-id = <159>;
>> +                    ti,sci-proc-ids = <0x01 0xFF>;
>> +                    resets = <&k3_reset 159 1>;
>> +                    firmware-name = "am65x-mcu-r5f0_0-fw";
>> +                    atcm-enable = <1>;
>> +                    btcm-enable = <1>;
>> +                    loczrama = <1>;
>> +                    mboxes = <&mailbox0 &mbox_mcu_r5fss0_core0>;
>> +                    memory-region = <&mcu_r5fss0_core0_dma_memory_region>,
>> +                                    <&mcu_r5fss0_core0_memory_region>;
>> +                    sram = <&mcu_r5fss0_core0_sram>;
>> +                };
>> +
>> +                mcu_r5f1: r5f@41400000 {
>> +                    compatible = "ti,am654-r5f";
>> +                    reg = <0x41400000 0x00008000>,
>> +                          <0x41410000 0x00008000>;
>> +                    reg-names = "atcm", "btcm";
>> +                    ti,sci = <&dmsc>;
>> +                    ti,sci-dev-id = <245>;
>> +                    ti,sci-proc-ids = <0x02 0xFF>;
>> +                    resets = <&k3_reset 245 1>;
>> +                    firmware-name = "am65x-mcu-r5f0_1-fw";
>> +                    atcm-enable = <1>;
>> +                    btcm-enable = <1>;
>> +                    loczrama = <1>;
>> +                    mboxes = <&mailbox1 &mbox_mcu_r5fss0_core1>;
>> +               };
>> +           };
>> +        };
>> +    };
>> --
>> 2.23.0
>>