Re: Re: [PATCH v2 02/13] dt-bindings: media: ti,j721e-csi2rx-shim: Support 32 dma chans

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Krzysztof,

Thanks for the review.

On Jul 01, 2024 at 11:30:13 +0200, Krzysztof Kozlowski wrote:
> On 27/06/2024 15:09, Jai Luthra wrote:
> > The CSI2RX SHIM IP can support a maximum of 32x DMA channels.
> > 
> > These can be used to split incoming "streams" of data on the CSI-RX
> > port, distinguished by MIPI Virtual Channel (or Data Type), into
> > different locations in memory (/dev/videoX nodes).
> > 
> > Actual number of DMA channels reserved is different for each SoC
> > integrating this IP, but a maximum of 32x channels are always available
> > in this IP's register space, so set minimum as 1 and maximum as 32.

Sorry, this above paragraph is incorrect. All variants of SoCs 
integrating this IP can in-fact support 32 channels.

I will update the commit description in the next revision to make this 
clearer.

> > 
> > Link: https://www.ti.com/lit/pdf/spruiv7
> > Signed-off-by: Jai Luthra <j-luthra@xxxxxx>
> > ---
> >  .../bindings/media/ti,j721e-csi2rx-shim.yaml       | 39 ++++++++++++++++++++--
> >  1 file changed, 36 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/media/ti,j721e-csi2rx-shim.yaml b/Documentation/devicetree/bindings/media/ti,j721e-csi2rx-shim.yaml
> > index f762fdc05e4d..0e00533c7b68 100644
> > --- a/Documentation/devicetree/bindings/media/ti,j721e-csi2rx-shim.yaml
> > +++ b/Documentation/devicetree/bindings/media/ti,j721e-csi2rx-shim.yaml
> > @@ -20,11 +20,44 @@ properties:
> >      const: ti,j721e-csi2rx-shim
> >  
> >    dmas:
> > -    maxItems: 1
> > +    minItems: 1
> > +    maxItems: 32
> >  
> >    dma-names:
> > +    minItems: 1
> >      items:
> >        - const: rx0
> 
> So all variants now get total random number of DMAs? I don't understand
> why this is not constrained.

The default system-level resource partitioning allocates < 32 channels 
for some platforms, though that can be changed by the user [1].

I don't think a separate compatible for constraints makes sense here, as 
this is not an IP or SoC-level constraint, and only depends on how the 
end-user allocates the channels across peripherals.

> 
> Best regards,
> Krzysztof
> 

[1] https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/latest/exports/docs/linux/How_to_Guides/Host/K3_Resource_Partitioning_Tool.html

-- 
Thanks,
Jai

GPG Fingerprint: 4DE0 D818 E5D5 75E8 D45A AFC5 43DE 91F9 249A 7145




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux