Re: [STLinux Kernel] [PATCH v2 2/4] remoteproc: dt: Provide bindings for ST's Remote Processor Controller driver

From: Peter Griffin
Date: Tue Sep 01 2015 - 04:58:35 EST

Hi Lee,

On Fri, 28 Aug 2015, Lee Jones wrote:

> Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
> ---
> .../devicetree/bindings/remoteproc/st-rproc.txt | 35 ++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/remoteproc/st-rproc.txt

The patch documening the DT bindings should be ordered before the patch which adds
the DT node to aid reviewing.
> diff --git a/Documentation/devicetree/bindings/remoteproc/st-rproc.txt b/Documentation/devicetree/bindings/remoteproc/st-rproc.txt
> new file mode 100644
> index 0000000..fbd7d78
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/remoteproc/st-rproc.txt
> @@ -0,0 +1,35 @@
> +STMicroelectronics Remote Processor
> +-----------------------------------
> +
> +This binding provides support for adjunct processors found on ST SoCs.
> +
> +The remote processors can be controlled from the bootloader or the primary OS.
> +If the bootloader starts a remote processor processor the primary OS must detect
> +its state and act accordingly.
> +
> +Required properties:
> +- compatible Should be one of:
> + "st,st231-rproc"
> + "st,st40-rproc"

st40-proc isn't used anywhere. The stih407 doesn't have a ST40 copro, and
looking in the vendor tree remoteproc support isn't present for stih415/6 which
are the the only upstream SoC's to have a ST40 co-pro.

So I think st40-rproc support can be removed.

> +- reg Size and length of reserved co-processor memory
> +- resets Reset lines (See: ../reset/reset.txt)
> +- reset-names Must be "sw_reset" and "pwr_reset"

pwr_reset isn't used by any of the st231 co-processors. It seems to
be related to ST40 support which I don't think is required upstream.
Removing it would make the driver a fair bit smaller.

> +- clocks Clock for co-processor (See: ../clock/clock-bindings.txt)
> +- clock-names Must be "rproc_clk"

I can't see any co-pro which uses more than one clock, so clock-names looks

> +- clock-frequency Clock frequency to set co-processor at if the bootloader
> + hasn't already done so
> +- st,syscfg-boot The register that holds the boot vector for the co-processor

I would prefer to see this binding match how most other sti drivers reference syscfg
registers which is: -

st,syscfg = <&syscfg_core 0xf4>;

Description: phandle of sysconfig bank plus integer array containing register offsets.

It also means it is easily extendable if more than one syscfg register is
required in the future to boot a co-pro.


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