Messages in this thread | | | Date | Thu, 9 Feb 2023 09:27:20 +0100 | From | neil.armstrong@linaro ... | Subject | Re: [PATCH] dt-bindings: dma: qcom,bam-dma: add optional memory interconnect properties |
| |
On 09/02/2023 09:25, Bhupesh Sharma wrote: > On 2/8/23 2:38 PM, neil.armstrong@linaro.org wrote: >> On 08/02/2023 10:03, Krzysztof Kozlowski wrote: >>> On 07/02/2023 16:27, Dmitry Baryshkov wrote: >>>> On 07/02/2023 15:35, Neil Armstrong wrote: >>>>> On 07/02/2023 11:32, Dmitry Baryshkov wrote: >>>>>> On 07/02/2023 12:03, Neil Armstrong wrote: >>>>>>> Recents SoCs like the SM8450 or SM8550 requires memory interconnect >>>>>>> in order to have functional DMA. >>>>>>> >>>>>>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org> >>>>>>> --- >>>>>>> Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml | 6 ++++++ >>>>>>> 1 file changed, 6 insertions(+) >>>>>> >>>>>> I suspect this will not work without a change for a driver. >>>>>> >>>>> >>>>> I had the impression single interconnect entries would be taken in account >>>>> by the platform core, but it doesn't seem to be the case, anyway I can;t >>>>> find >>>>> any code doing that. >>>> >>>> Probably you mixed interconnects and power-domains here. >>>> >>> >>> The driver change was submitted some time ago: >>> https://lore.kernel.org/all/20210505213731.538612-10-bhupesh.sharma@linaro.org/ >>> >>> There is already DTS user of it and we expect driver to be resubmitted >>> at some point. >>> >>> What I don't really get is that crypto driver sets bandwidth for >>> interconnects, not the BAM. Why BAM needs interconnect? Usually you do >>> not need to initialize some middle paths. Getting the final interconnect >>> path (e.g. crypto-memory) is enough, because it includes everything in >>> between. >> >> Indeed the interconnect on BAM may be redundant since QCE sets the BW, >> I'll investigate to understand if it's also necessary on BAM. > > Since we are already doing this via QCE driver (since crypto block on qcom SoCs employs BAM DMA services) via [1], this change is not needed for sm8150, sm8250, sm8350 and subsequent qcom SoCs (available presently), so this patch can be dropped.
Ack, I'll push a patch to remove the interconnect properties from the BAM node in sm8550.
Neil
> > [1]. https://www.spinics.net/lists/linux-arm-msm/msg142957.html > > Thanks, > Bhupesh
| |