Re: [PATCH v5 1/3] dt-bindings: media: imx-jpeg: Assign slot for imx jpeg encoder/decoder

[ming qian]

Hi Krzysztof,

> > From: Ming Qian <ming.qian@xxxxxxx>
> >
> > This IP includes a jpeg wrapper and a jpeg engine, the wrapper is
> > working on descriptor based manner. It supports up to 4 slots, each slot
> > can have its own chained descriptors. Host won't configure the engine
> > directly, but fill some descriptors to encode or decode one jpeg
> > picture. Then configure the descriptors to certain slot register. The
> > jpeg wrapper will schedule between different slots. When some slot is
> > finished, the slot interrupt will be triggered. The purpose of slot is
> > that engine can be shared across multiple VMS and os.
> >
> > Currently, power domains and interrupts are enabled for all 4 slots, but
> > only one slot is used. There is no benefit in using more that one slot
> > from within the same OS, as the slots are scheduled in round-robin
> > manner and not executed in parallel.
> >
> > Use the property "nxp,slot" to assign a single slot, and just expose the
> > parts of the h/w for the assigned slot. For example, only put slot 1's
> > power-domains entry in the DT when slot 1 is assigned. If not specified,
> > 0 is used by default.
> >
> > Signed-off-by: Ming Qian <ming.qian@xxxxxxx>
> > ---
> > v5
> > - improve commit message
> > - improve property description
> >
> > v4
> > - improve commit message
> > - drop line making the property required, to avoid ABI break
> >
> > v3
> > - add vender prefix, change property slot to nxp,slot
> > - add type for property slot
> >
> > v2
> > - add a new property in bindings document
> >
> >   .../bindings/media/nxp,imx8-jpeg.yaml         | 46 +++++++++----------
> >   1 file changed, 22 insertions(+), 24 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml b/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml
> > index 3d9d1db37040..0961856bdcab 100644
> > --- a/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml
> > +++ b/Documentation/devicetree/bindings/media/nxp,imx8-jpeg.yaml
> > @@ -32,19 +32,27 @@ properties:
> >       maxItems: 1
> >   
> >     interrupts:
> > -    description: |
> > -      There are 4 slots available in the IP, which the driver may use
> > -      If a certain slot is used, it should have an associated interrupt
> > -      The interrupt with index i is assumed to be for slot i
> > -    minItems: 1               # At least one slot is needed by the driver
> > -    maxItems: 4               # The IP has 4 slots available for use
> > +    description:
> > +      Interrupt number for slot
> > +    maxItems: 1
>
> The device still has four interrupts, so we should allow up to four of
> them. One given OS might want to use two or all four slots.
Got it, I will fix it in v6 patch.

> >   
> >     power-domains:
> >       description:
> >         List of phandle and PM domain specifier as documented in
> >         Documentation/devicetree/bindings/power/power_domain.txt
> > -    minItems: 2               # Wrapper and 1 slot
> > -    maxItems: 5               # Wrapper and 4 slots
> > +    minItems: 1               # Mixed power domain
> > +    maxItems: 2               # Wrapper and 1 slot
> > +
> > +  nxp,slot:
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    description:
> > +      Integer number of slot index used. This IP includes a jpeg wrapper, the
> > +      wrapper is working on descriptor based manner. It supports up to 4 slots,
> > +      each slot can have its own chained descriptors. The purpose is to share
> > +      the jpeg engine across multiple VMS and os. We use this property to
> > +      assign a single slot. If not specified, 0 is used by default.
> > +    minimum: 0
> > +    maximum: 3
>
> default: 0
Got it.

Best regards,
Ming
> Best regards,
> Krzysztof