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From: "Martin Povišer" <povik@cutebit.org>
To: Rob Herring <robh@kernel.org>
Cc: "Martin Povišer" <povik+lin@cutebit.org>,
	"Hector Martin" <marcan@marcan.st>,
	"Sven Peter" <sven@svenpeter.dev>,
	"Vinod Koul" <vkoul@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Alyssa Rosenzweig" <alyssa@rosenzweig.io>,
	linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Mark Kettenis" <kettenis@openbsd.org>
Subject: Re: [PATCH v2 1/2] dt-bindings: dma: Add Apple ADMAC
Date: Thu, 14 Apr 2022 19:52:36 +0200	[thread overview]
Message-ID: <A9849767-1A50-4C57-AE40-3DD7FB475130@cutebit.org> (raw)
In-Reply-To: <85DF53F6-74BA-4D8D-8E8E-DFD67B24DA19@cutebit.org>


> On 14. 4. 2022, at 19:23, Martin Povišer <povik@cutebit.org> wrote:
> 
>> 
>> On 14. 4. 2022, at 17:43, Rob Herring <robh@kernel.org> wrote:
>> 
>> On Tue, Apr 12, 2022 at 12:22:03AM +0200, Martin Povišer wrote:
>>> Apple's Audio DMA Controller (ADMAC) is used to fetch and store audio
>>> samples on SoCs from the "Apple Silicon" family.
>>> 
>>> Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
>>> ---
>>> 
>>> After the v1 discussion, I dropped the apple,internal-irq-destination
>>> property and instead the index of the usable interrupt is now signified
>>> by prepending -1 entries to the interrupts= list. This works when I do
>>> it like this:
>>> 
>>> interrupt-parent = <&aic>;
>>> interrupts = <AIC_IRQ 0xffffffff 0>,
>>> <AIC_IRQ 626 IRQ_TYPE_LEVEL_HIGH>;
>> 
>> 
>> BTW, just use '-1'. dtc takes negative values (and other expressions).
> 
> Ha! <-1> didn’t work for me but <(-1)> does.
> 
>> 
>>> 
>>> I would find it neat to do it like this:
>>> 
>>> interrupts-extended = <0xffffffff>,
>>> <&aic AIC_IRQ 626 IRQ_TYPE_LEVEL_HIGH>;
>>> 
>>> but unfortunately the kernel doesn't pick up on it:
>>> 
>>> [ 0.767964] apple-admac 238200000.dma-controller: error -6: IRQ index 0 not found
>>> [ 0.773943] apple-admac 238200000.dma-controller: error -6: IRQ index 1 not found
>>> [ 0.780154] apple-admac 238200000.dma-controller: error -6: IRQ index 2 not found
>>> [ 0.786367] apple-admac 238200000.dma-controller: error -6: IRQ index 3 not found
>>> [ 0.788592] apple-admac 238200000.dma-controller: error -6: no usable interrupt
>> 
>> We should make this case work. It is less fragile IMO as it doesn't 
>> depend on the provider's translation of cells.
> 
> Then I may send some patch to that end.

Turns out there’s no need. Passing in <0> in place of a phandle reference
looks like what we want:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/of/base.c?h=v5.18-rc2#n1334

(Confirmed by testing to do the right thing with the IRQs.)

Martin

WARNING: multiple messages have this Message-ID (diff)
From: "Martin Povišer" <povik@cutebit.org>
To: Rob Herring <robh@kernel.org>
Cc: "Martin Povišer" <povik+lin@cutebit.org>,
	"Hector Martin" <marcan@marcan.st>,
	"Sven Peter" <sven@svenpeter.dev>,
	"Vinod Koul" <vkoul@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Alyssa Rosenzweig" <alyssa@rosenzweig.io>,
	linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Mark Kettenis" <kettenis@openbsd.org>
Subject: Re: [PATCH v2 1/2] dt-bindings: dma: Add Apple ADMAC
Date: Thu, 14 Apr 2022 19:52:36 +0200	[thread overview]
Message-ID: <A9849767-1A50-4C57-AE40-3DD7FB475130@cutebit.org> (raw)
In-Reply-To: <85DF53F6-74BA-4D8D-8E8E-DFD67B24DA19@cutebit.org>


> On 14. 4. 2022, at 19:23, Martin Povišer <povik@cutebit.org> wrote:
> 
>> 
>> On 14. 4. 2022, at 17:43, Rob Herring <robh@kernel.org> wrote:
>> 
>> On Tue, Apr 12, 2022 at 12:22:03AM +0200, Martin Povišer wrote:
>>> Apple's Audio DMA Controller (ADMAC) is used to fetch and store audio
>>> samples on SoCs from the "Apple Silicon" family.
>>> 
>>> Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
>>> ---
>>> 
>>> After the v1 discussion, I dropped the apple,internal-irq-destination
>>> property and instead the index of the usable interrupt is now signified
>>> by prepending -1 entries to the interrupts= list. This works when I do
>>> it like this:
>>> 
>>> interrupt-parent = <&aic>;
>>> interrupts = <AIC_IRQ 0xffffffff 0>,
>>> <AIC_IRQ 626 IRQ_TYPE_LEVEL_HIGH>;
>> 
>> 
>> BTW, just use '-1'. dtc takes negative values (and other expressions).
> 
> Ha! <-1> didn’t work for me but <(-1)> does.
> 
>> 
>>> 
>>> I would find it neat to do it like this:
>>> 
>>> interrupts-extended = <0xffffffff>,
>>> <&aic AIC_IRQ 626 IRQ_TYPE_LEVEL_HIGH>;
>>> 
>>> but unfortunately the kernel doesn't pick up on it:
>>> 
>>> [ 0.767964] apple-admac 238200000.dma-controller: error -6: IRQ index 0 not found
>>> [ 0.773943] apple-admac 238200000.dma-controller: error -6: IRQ index 1 not found
>>> [ 0.780154] apple-admac 238200000.dma-controller: error -6: IRQ index 2 not found
>>> [ 0.786367] apple-admac 238200000.dma-controller: error -6: IRQ index 3 not found
>>> [ 0.788592] apple-admac 238200000.dma-controller: error -6: no usable interrupt
>> 
>> We should make this case work. It is less fragile IMO as it doesn't 
>> depend on the provider's translation of cells.
> 
> Then I may send some patch to that end.

Turns out there’s no need. Passing in <0> in place of a phandle reference
looks like what we want:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/of/base.c?h=v5.18-rc2#n1334

(Confirmed by testing to do the right thing with the IRQs.)

Martin
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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-04-14 17:52 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-11 22:22 [PATCH v2 0/2] Apple ADMAC driver Martin Povišer
2022-04-11 22:22 ` Martin Povišer
2022-04-11 22:22 ` [PATCH v2 1/2] dt-bindings: dma: Add Apple ADMAC Martin Povišer
2022-04-11 22:22   ` Martin Povišer
2022-04-14 15:43   ` Rob Herring
2022-04-14 15:43     ` Rob Herring
2022-04-14 17:23     ` Martin Povišer
2022-04-14 17:23       ` Martin Povišer
2022-04-14 17:52       ` Martin Povišer [this message]
2022-04-14 17:52         ` Martin Povišer
2022-04-11 22:22 ` [PATCH v2 2/2] dmaengine: apple-admac: Add Apple ADMAC driver Martin Povišer
2022-04-11 22:22   ` Martin Povišer
2022-04-20 12:40   ` Vinod Koul
2022-04-20 12:40     ` Vinod Koul
2022-04-20 13:41     ` Martin Povišer
2022-04-20 13:41       ` Martin Povišer

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