> On 31. 3. 2022, at 19:21, Rob Herring <robh@xxxxxxxxxx> wrote: > > On Thu, Mar 31, 2022 at 06:13:53PM +0200, Martin Povišer wrote: >> >>> On 31. 3. 2022, at 16:10, Vinod Koul <vkoul@xxxxxxxxxx> wrote: >>> >>> On 31-03-22, 09:06, Martin Povišer wrote: >>>> >>>>> On 31. 3. 2022, at 8:50, Martin Povišer <povik@xxxxxxxxxxx> wrote: >>>>>> >>>>>> On 31. 3. 2022, at 7:23, Vinod Koul <vkoul@xxxxxxxxxx> wrote: >>>>>> >>>>>> On 30-03-22, 18:44, Martin Povišer wrote: >>>>>>> Apple's Audio DMA Controller (ADMAC) is used to fetch and store audio >>>>>>> samples on Apple SoCs from the "Apple Silicon" family. >>>>>>> >>>>>>> Signed-off-by: Martin Povišer <povik+lin@xxxxxxxxxxx> >>>>>>> --- >>>>>>> .../devicetree/bindings/dma/apple,admac.yaml | 73 +++++++++++++++++++ >>>>>>> 1 file changed, 73 insertions(+) >>>>>>> create mode 100644 Documentation/devicetree/bindings/dma/apple,admac.yaml >>>>>>> >>>>>>> diff --git a/Documentation/devicetree/bindings/dma/apple,admac.yaml b/Documentation/devicetree/bindings/dma/apple,admac.yaml >>>>>>> new file mode 100644 >>>>>>> index 000000000000..34f76a9a2983 >>>>>>> --- /dev/null >>>>>>> +++ b/Documentation/devicetree/bindings/dma/apple,admac.yaml >>>>> >>>>>>> + apple,internal-irq-destination: >>>>>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>>>>> + description: Index influencing internal routing of the IRQs >>>>>>> + within the peripheral. >>>>>> >>>>>> do you have more details for this, is this for peripheral and if so >>>>>> suited to be in dam-cells? >>>>> >>>>> By peripheral I meant the DMA controller itself here. >>> >>> Dmaengine convention is that peripheral is device which we are doing dma >>> to/from, like audio controller/fifo here >>> >>>>> Effectively the controller has four independent IRQ outputs and the driver >>>>> needs to know which one we are using. (It need not be the same output even >>>>> for different ADMAC instances on one die.) >>> >>> That smells like a mux to me.. why not use dma-requests for this? >> >> I am not sure that’s right. Reading the dmaengine docs, DMA requests seem to have >> to do with the DMA-controller-to-peripheral connection, but the proposed property >> tells us which of four independent IRQ outputs of the DMA controller we actually >> have in the interrupts= property. That is, it has to do with the DMA-controller-to-CPU >> connection. > > Why do they have to be different? IRQF_SHARED doesn't work? It’s not that the IRQ outputs of different controllers are overlaid. It’s that e.g. first output of controller A is hooked up to some input of the AP’s interrupt controller, the third output of controller B is hooked to another input, but for all we know the other controller outputs lead to nowhere or to some coprocessor. > Why can't you request each IRQ until it succeeds? > > What happens when there are 5 DMA controllers? > > If using more than 1 interrupt will never work or be needed, then I'm > inclined to say just describe that 1 interrupt. Yes, that goes against > 'describe all the h/w', but there's always exceptions. I suppose you > need to know which 'interrupts' index (output) you are using. If so, you > can do something like this: > > interrupts = <-1>, <-1>, <3 0>, <-1>; That’s actually exactly what I want! In next iteration of the binding I will drop the vendor property and do that. > > Rob Martin
