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Date: Fri, 10 Jun 2022 09:17:31 -0700
From: Tanmay Shah <tanmay.shah@...inx.com>
To: Rob Herring <robh@...nel.org>,
Peter Korsgaard <peter@...sgaard.com>
CC: <bjorn.andersson@...aro.org>, <mathieu.poirier@...aro.org>,
<krzk+dt@...nel.org>, <michal.simek@...inx.com>,
<ben.levinsky@...inx.com>, <linux-remoteproc@...r.kernel.org>,
<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<openamp-system-reference@...ts.openampproject.org>
Subject: Re: [PATCH v8 1/6] dt-bindings: remoteproc: Add Xilinx RPU subsystem
bindings
HI Rob,
Thanks for reviews. Please find my comments below.
On 6/9/22 10:41 AM, Rob Herring wrote:
> On Fri, Jun 03, 2022 at 08:33:13AM +0200, Peter Korsgaard wrote:
>>>>>>> "Tanmay" == Tanmay Shah <tanmay.shah@...inx.com> writes:
>> Hi,
>>
>> > 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@...inx.com>
>> > ---
>>
>> > Changes in v8:
>> > - Add 'items:' for sram property
>>
>> > Changes in v7:
>> > - Add minItems in sram property
>>
>> > Changes in v6:
>> > - Add maxItems to sram and memory-region property
>>
>> > Changes in v5:
>> > - Add constraints of the possible values of xlnx,cluster-mode property
>> > - fix description of power-domains property for r5 core
>> > - Remove reg, address-cells and size-cells properties as it is not required
>> > - Fix description of mboxes property
>> > - Add description of each memory-region and remove old .txt binding link
>> > reference in the description
>>
>> > Changes in v4:
>> > - Add memory-region, mboxes and mbox-names properties in example
>>
>> > Changes in v3:
>> > - None
>>
>> > .../bindings/remoteproc/xlnx,r5f-rproc.yaml | 130 ++++++++++++++++++
>> > include/dt-bindings/power/xlnx-zynqmp-power.h | 6 +
>> > 2 files changed, 138 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..adfe05ff157a
>> > --- /dev/null
>> > +++ b/Documentation/devicetree/bindings/remoteproc/xlnx,r5f-rproc.yaml
>> > @@ -0,0 +1,132 @@
>> > +# 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@...inx.com>
>> > + - Tanmay Shah <tanmay.shah@...inx.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:
>> > + $ref: /schemas/types.yaml#/definitions/uint32
>> > + enum: [0, 1, 2]
>>
>> A textual mode ("dual", "lock-step", "single") would be more readable.
>>
>>
>> > + description: |
>> > + The RPU MPCore can operate in split mode(Dual-processor performance), Safety
>>
>> space missing before "(Dual-processor"
>>
>>
>> > + lock-step mode(Both RPU cores execute the same code in lock-step,
>> > + clock-for-clock) or Single CPU mode (RPU core 0 can be held in reset while
>>
>> "can be" sounds a bit weak, perhaps "is"
>>
>>
>> > + core 1 runs normally). The processor does not support dynamic configuration.
>> > + Switching between modes is only permitted immediately after a processor reset.
>> > + If set to 1 then lockstep mode and if 0 then split mode.
>> > + If set to 2 then single CPU mode. When not defined, default will be lockstep mode.
>>
>> This looks a bit confusing. If you decide to stick to the numerical
>> modes, then at least list them in numerical order, E.G.:
>>
>> 0: split
>> 1: lockstep
>> 2: single
I think the description is fine. for readability I can just add
numerical order as above.
> The bigger issue has been multiple Cortex-R5 bindings all doing their
> own thing for this feature which is not vendor specific (except TI has
> their own extra mode or something). How TCMs are described is the
> other issue. I've just stopped caring because no one listens.
Values used for cluster-mode property for xlnx platform is same as ti's
cluster mode property.
0: split, 1: lockstep and 2: single-cpu mode. It is matching with
ti,k3-r5 bindings.
However, default value for some of the ti platforms are different.
xlnx platforms have single-cpu mode as well.
It will take some time to design system-dt spec for TCM.
So, for now I use hard-code values of TCM from driver.
TCM bindings for linux will be posted once system-dt spec is accepted.
Meanwhile we would like to upstream rest of the bindings and driver.
>
>>> +
>> > +patternProperties:
>> > + "^r5f-[a-f0-9]+$":
>> > + 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: RPU core PM domain specifier
>> > + maxItems: 1
>>
>> A bit more detail would be good, E.G. something like arm/cpus.yaml does:
>>
>> List of phandles and PM domain specifiers, as defined by bindings of the
>> PM domain provider (see also ../power_domain.txt).
>>
>> And the phandle-array ref.
> Both suggestions are wrong. We don't need common properties re-described
> by every user. They already have a type definition too, so we don't need
> to repeat phandle-array ref either.
>
> The existing description is not needed either as it doesn't provide any
> information specific to this binding. You only need to describe each
> entry when there is more than 1 entry because we need to know what each
> entry is and the order.
I will remove current description as well.
Thanks.
>
>>> +
>> > + mboxes:
>> > + minItems: 1
>> > + items:
>> > + - description: mailbox channel to send data to RPU
>> > + - description: mailbox channel to receive data from RPU
>> > +
>> > + mbox-names:
>> > + minItems: 1
>> > + items:
>> > + - const: tx
>> > + - const: rx
>>
>> And here as well for mailbox/mailbox.txt
> Nope!
>
>>
>> > +
>> > + sram:
>> > + $ref: /schemas/types.yaml#/definitions/phandle-array
>> > + minItems: 1
>> > + maxItems: 8
>> > + items:
>> > + maxItems: 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.
>>
>> Drop the comma after "from"
>>
>>
>> > +
>> > + The regions should be defined as child nodes of the respective SRAM
>> > + node, and should be defined as per the generic bindings in,
>>
>> Drop the comma after "in"
>>
>>
>> > + Documentation/devicetree/bindings/sram/sram.yaml
>> > +
>> > + memory-region:
>> > + 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.
>>
>> s/on DDR/in DDR/
>>
>> > + minItems: 1
>> > + maxItems: 8
>> > + items:
>> > + - description: region used for RPU firmware image section
>> > + - description: vdev buffer
>> > + - description: vring0
>> > + - description: vring1
>> > + additionalItems: true
>> > +
>> > + required:
>> > + - compatible
>> > + - power-domains
>> > +
>> > + unevaluatedProperties: false
>> > +
>> > +required:
>> > + - compatible
>> > +
>> > +additionalProperties: false
>> > +
>> > +examples:
>> > + - |
>> > + r5fss: r5fss {
>> > + compatible = "xlnx,zynqmp-r5fss";
>> > + xlnx,cluster-mode = <1>;
>> > +
>> > + r5f-0 {
>> > + compatible = "xlnx,zynqmp-r5f";
>> > + power-domains = <&zynqmp_firmware 0x7>;
>> > + memory-region = <&rproc_0_fw_image>, <&rpu0vdev0buffer>, <&rpu0vdev0vring0>, <&rpu0vdev0vring1>;
>> > + mboxes = <&ipi_mailbox_rpu0 0>, <&ipi_mailbox_rpu0 1>;
>> > + mbox-names = "tx", "rx";
>> > + };
>> > +
>> > + r5f-1 {
>> > + compatible = "xlnx,zynqmp-r5f";
>> > + power-domains = <&zynqmp_firmware 0x8>;
>> > + memory-region = <&rproc_1_fw_image>, <&rpu1vdev0buffer>, <&rpu1vdev0vring0>, <&rpu1vdev0vring1>;
>> > + mboxes = <&ipi_mailbox_rpu1 0>, <&ipi_mailbox_rpu1 1>;
>> > + mbox-names = "tx", "rx";
>> > + };
>> > + };
>> > +...
>> > 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
>>
>>
>> --
>> Bye, Peter Korsgaard
>>
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