Re: [PATCH v2 2/4] dt-bindings: remoteproc: Add bindings for C66x DSPs on TI K3 SoCs

Suman Anna
2020-05-28T22:48:17Z

Hi Rob,

On 5/28/20 5:32 PM, Rob Herring wrote:
> On Wed, May 20, 2020 at 07:10:04PM -0500, Suman Anna wrote:
>> Some Texas Instruments K3 family of SoCs have one of more Digital Signal
>> Processor (DSP) subsystems that are comprised of either a TMS320C66x
>> CorePac and/or a next-generation TMS320C71x CorePac processor subsystem.
>> Add the device tree bindings document for the C66x DSP devices on these
>> SoCs. The added example illustrates the DT nodes for the first C66x DSP
>> device present on the K3 J721E family of SoCs.
>>
>> Signed-off-by: Suman Anna <s-anna@ti.com>
>> ---
>> v2:
>> - Updated the example to include the root-node to fix the bot errors from v1
>
> Pretty sure that was not why you had errors.

It is because of the default values used for #address-cells and
#size-cells in the example_template and example_start variables used in
the dt-extract-example script. They are 1 by default, so the generated
template ended up with the root-node using 1, and the actual example
using 2 resulting in the mismatch.

When I updated the script to use 2 for both #address-cells and
#size-cells, then the warnings go away. This is the reason, dtbs_check
on my actual dts files goes through fine.

>
>> - Added maxItems to resets, mboxes, memory-region, sram properties
>> - Changed the ti,sci-proc-ids $ref to uint-array from uint-matrix
>> - Addressed the minor review comments from Mathieu
>> v1: https://patchwork.kernel.org/patch/11458571/
>>
>> .../bindings/remoteproc/ti,k3-dsp-rproc.yaml | 190 ++++++++++++++++++
>> 1 file changed, 190 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml
>> new file mode 100644
>> index 000000000000..cdf649655838
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml
>> @@ -0,0 +1,190 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/remoteproc/ti,k3-dsp-rproc.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: TI K3 DSP devices
>> +
>> +maintainers:
>> + - Suman Anna <s-anna@ti.com>
>> +
>> +description: |
>> + The TI K3 family of SoCs usually have one or more TI DSP Core sub-systems
>> + that are used to offload some of the processor-intensive tasks or algorithms,
>> + for achieving various system level goals.
>> +
>> + These processor sub-systems usually contain additional sub-modules like
>> + L1 and/or L2 caches/SRAMs, an Interrupt Controller, an external memory
>> + controller, a dedicated local power/sleep controller etc. The DSP processor
>> + cores in the K3 SoCs are usually either a TMS320C66x CorePac processor or a
>> + TMS320C71x CorePac processor.
>> +
>> + Each DSP Core sub-system is represented as a single DT node. Each node has a
>> + number of required or optional properties that enable the OS running on the
>> + host processor (Arm CorePac) to perform the device management of the remote
>> + processor and to communicate with the remote processor.
>> +
>> +properties:
>> + compatible:
>> + const: ti,j721e-c66-dsp
>> + description:
>> + Use "ti,j721e-c66-dsp" for C66x DSPs on K3 J721E SoCs
>
> What else are you going to use? There's only one compatible string. Drop
> description.

Is updated in a subsequent binding update where I added the C71 support.

>
>> +
>> + 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.
>
> Don't need generic descriptions. That's every 'reg'.
>
> What you can do is an 'items' list describing what each region is.

OK, I am bit confused here. I have listed the items under the reg-names,
while using just the minItems or maxItems here. What is the convention,
aren't reg and reg-names associative.

>
>> + minItems: 3
>> + maxItems: 3
>> +
>> + reg-names:
>> + description: |
>> + Should contain strings with the names of the specific internal
>> + memory regions, and should be defined in this order
>
> Again, drop.

OK

>
>> + maxItems: 3
>> + items:
>> + - const: l2sram
>> + - const: l1pram
>> + - const: l1dram
>> +
>> + 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 DSP core.
>> + Please refer to the corresponding System Controller documentation
>> + for valid values for the DSP cores.
>> +
>> + ti,sci-proc-ids:
>> + description: Should contain a single tuple of <proc_id host_id>.
>> + allOf:
>> + - $ref: /schemas/types.yaml#/definitions/uint32-array
>> + - maxItems: 1
>> + items:
>> + items:
>> + - description: TI-SCI processor id for the DSP core device
>> + - description: TI-SCI host id to which processor control
>> + ownership should be transferred to
>
> I assume these properties appear in multiple TI nodes? We don't need
> them defined multiple times. Create a schema for them that you can
> include here.

Only the remoteprocs, so they are limited to this binding and one more
R5F remoteproc binding.

>
>> +
>> + resets:
>> + description: |
>> + Should contain the phandle to the reset controller node
>> + managing the local 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
>
> Drop.

Entire description or just the reference to the reset bindings file?

>
>> + maxItems: 1
>> +
>> + firmware-name:
>> + description: |
>> + Should contain the name of the default firmware image
>> + file located on the firmware search path
>> +
>> + 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
>
> Drop. What mailbox provider is used is outside the scope of this
> binding.

OK.

>
>> + maxItems: 1
>> +
>> + memory-region:
>> + minItems: 2
>> + maxItems: 8
>> + description: |
>> + phandle to the reserved memory nodes to be associated with the remoteproc
>> + device. There should be at least two reserved memory nodes defined - the
>> + 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
>
> items:
> - description: dynamic DMA allocations like vrings and vring buffers
> - description: firmware image section ???
> - description: firmware image section ???

Yeah, this is scalable if we will have multiple separate DDR regions. I
had to choose a decent maxItems value, so I chose 8. Wouldn't listing
the individual items override the number of minItems/maxItems?

>
>> +
>> +# Optional properties:
>> +# --------------------
>> +
>> + sram:
>> + $ref: /schemas/types.yaml#/definitions/phandle-array
>> + minItems: 1
>> + maxItems: 4
>> + description: |
>> + phandles to one or more reserved on-chip SRAM regions. 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
>> + - mboxes
>> + - memory-region
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> + - |
>> + / {
>> + model = "Texas Instruments K3 J721E SoC";
>> + compatible = "ti,j721e";
>> + #address-cells = <2>;
>> + #size-cells = <2>;
>> +
>> + /* DSP Carveout reserved memory nodes */
>> + reserved-memory {
>> + #address-cells = <2>;
>> + #size-cells = <2>;
>> + ranges;
>> +
>> + c66_0_dma_memory_region: c66-dma-memory@a6000000 {
>> + compatible = "shared-dma-pool";
>> + reg = <0x00 0xa6000000 0x00 0x100000>;
>> + no-map;
>> + };
>> +
>> + c66_0_memory_region: c66-memory@a6100000 {
>> + compatible = "shared-dma-pool";
>> + reg = <0x00 0xa6100000 0x00 0xf00000>;
>> + no-map;
>> + };
>> + };
>
> Drop all of this. Outside the scope of this binding. And will likely
> start failing validation as schemas become more complete.

This is a complete example because of the memory-region references below.

>
>> +
>> + cbass_main: bus@100000 {
>
> Drop unused labels.

OK.

regards
Suman

>
>> + compatible = "simple-bus";
>> + #address-cells = <2>;
>> + #size-cells = <2>;
>> + ranges = <0x00 0x00100000 0x00 0x00100000 0x00 0x00020000>, /* ctrl mmr */
>> + <0x4d 0x80800000 0x4d 0x80800000 0x00 0x00800000>, /* C66_0 */
>> + <0x4d 0x81800000 0x4d 0x81800000 0x00 0x00800000>; /* C66_1 */
>> +
>> + /* J721E C66_0 DSP node */
>> + c66_0: dsp@4d80800000 {
>> + compatible = "ti,j721e-c66-dsp";
>> + reg = <0x4d 0x80800000 0x00 0x00048000>,
>> + <0x4d 0x80e00000 0x00 0x00008000>,
>> + <0x4d 0x80f00000 0x00 0x00008000>;
>> + reg-names = "l2sram", "l1pram", "l1dram";
>> + ti,sci = <&dmsc>;
>> + ti,sci-dev-id = <142>;
>> + ti,sci-proc-ids = <0x03 0xFF>;
>> + resets = <&k3_reset 142 1>;
>> + firmware-name = "j7-c66_0-fw";
>> + memory-region = <&c66_0_dma_memory_region>,
>> + <&c66_0_memory_region>;
>> + mboxes = <&mailbox0_cluster3 &mbox_c66_0>;
>> + };
>> + };
>> + };
>> --
>> 2.26.0
>>