From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 163293002AB; Thu, 27 Aug 2026 06:03:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787810613; cv=none; b=fSTmyRCetUYe71h0jry8ZItwfY6AI6i8Sr3GCH4sJDfLiajjeAL8WPrba1+UhrcDgLyCk6jq3f6gPApc9ZTOHs3YZWZE4xLgHOx3l4YL12fTyqwm5iVXH+tlIkhdYzB5Ckg1eE7Y3Pefi199TO4XWAEqvU3HxeainDSWiHtlGaU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787810613; c=relaxed/simple; bh=eVYzJGAIjQtqQDbeCgDE5Md9phOns18vg8xOXxuMsRk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kVLxX24/5F0iyNvAqCWi7NnfwDSO83Jii7qEs2vaUlZn4ye4QxbQwGA1pf/l75eac9nhT8/3fkQ1wRIKHHwK8cpWaxmwCJXKRnMiRf3Oa+nNe8fkYqvpcb+lb5u234pEaWu6H6NfmJhEwAG27jWNweoOO9TzL1lJMQHeSk9lGgQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=b084J/mv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="b084J/mv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 564891F000E9; Thu, 27 Aug 2026 06:03:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787810611; bh=lJlXA2kwLoTfDo4tJ3+9iNIhRW5M0Zb7cMLr/tH8zJU=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=b084J/mvtWIlJZRA0TvNW50gmDidKFYYLtXiIK/+EoWo8nNi4HZFQ3RB3pKZ5yJsR xZGJn1oGgULrLcLlNvk7dAbFeSgjaQrG0Hf/wTVMpUC0e9WuJmN8dSJb/XoxMHhuLc EzfisW4LrqLTvEnKd5wCvjoAtgUCs2ITmC442ys/wQRgEqZn7wo3bUmAwLXNXxMT/W PcbmYMtuw4qCRWlX2+X+Rfvba95TbSBBWGO3L5CC99QbgE1l2qFIeJ4IPhWdw11b6V ohlPjU8eqZvh4qZEbOOZ4lXr4SSpZzIfTxPDsZeqJ862KqHE24iw+QJmhlrJAGt/aC Xj1ditT75Gb2w== Message-ID: <006617c6-e3b0-4a3b-85e5-6b5af8f11879@kernel.org> Date: Thu, 27 Aug 2026 08:03:24 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/3] dt-bindings: sound: qcom,q6apm-dai: add stage-2 (SCM/VMID) access model To: Ajay Kumar Nandam , Srinivas Kandagatla , Liam Girdwood , Mark Brown , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jaroslav Kysela , Takashi Iwai Cc: linux-sound@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260826-a2a-shikra-vmid-v5-v2-0-c3dc62354eee@oss.qualcomm.com> <20260826-a2a-shikra-vmid-v5-v2-1-c3dc62354eee@oss.qualcomm.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 25/08/2026 20:40, Ajay Kumar Nandam wrote: > The APM DAIs expose PCM buffers that the backing DSP must be able to > reach. On existing targets the DSP runs in a stage-1 context and the > buffers are described to the SMMU via the iommus property. > > On platforms such as Qualcomm Shikra, where audio is served by the modem > DSP (mDSP) rather than the ADSP, the DSP runs in a stage-2 protected > context and cannot use the SMMU. The buffers are reachable only after > hypervisor (SCM) memory assignment to the fixed set of consumer Virtual > Machine IDs (VMIDs) that own that protected context. Describe those > consumers with a new qcom,vmids property. > > The two access models are mutually exclusive: a node carries either > iommus (stage-1/SMMU) or qcom,vmids (stage-2/SCM), expressed with a > oneOf constraint. iommus is therefore no longer unconditionally required. > SCM assignment replaces the buffer's current owners with the supplied > destination set, so the driver always adds HLOS to that set itself to > retain host access; HLOS must not be listed in qcom,vmids. > > When qcom,vmids is present the PCM buffers must reside in reserved-memory > carveouts that are SCM-assigned to the consumer VMIDs. Add an optional > memory-region property listing those carveouts. The first entry is the > control-path buffer and subsequent entries are data-path buffers. > memory-region is only meaningful alongside qcom,vmids, enforced via > dependentRequired. > > Signed-off-by: Ajay Kumar Nandam > --- > .../devicetree/bindings/sound/qcom,q6apm-dai.yaml | 72 +++++++++++++++++++++- > 1 file changed, 70 insertions(+), 2 deletions(-) > > diff --git a/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml b/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml > index 9e5b30d9c6e6..d9a6bc4a14f2 100644 > --- a/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml > +++ b/Documentation/devicetree/bindings/sound/qcom,q6apm-dai.yaml > @@ -10,7 +10,15 @@ maintainers: > - Srinivas Kandagatla > > description: | > - This binding describes the Qualcomm APM DAIs in DSP > + This binding describes the Qualcomm APM DAIs in DSP. > + > + The DSP that runs the APM must be able to reach the PCM buffers. On > + existing targets the DSP runs in a stage-1 context and the buffers are > + described to the SMMU via iommus. On targets whose APM DSP runs in a > + stage-2 protected context that cannot use the SMMU, the buffers are > + reachable only after hypervisor (SCM) memory assignment to the fixed > + set of consumer VMIDs that own that protected context, described by > + qcom,vmids. The two access models are mutually exclusive. > > properties: > compatible: > @@ -20,9 +28,42 @@ properties: > minItems: 1 > maxItems: 2 As I said last time, different hardware, different programming interface, different features, so a different compatible. > > + memory-region: > + description: > + Reserved-memory carveouts (shared-dma-pool, no-map) that hold the > + PCM buffers and must be SCM-assigned to the VMIDs in qcom,vmids. > + The first entry is the control-path buffer; the second entry is > + the data-path buffer. Only used together with qcom,vmids. > + minItems: 1 > + maxItems: 2 List the items with description, isntead of free form text items: - description: - description: > + > + qcom,vmids: > + description: > + Virtual Machine IDs (VMIDs) of the processors that consume the PCM > + buffers and therefore must be granted access through SCM memory > + assignment. Required on targets whose APM DSP runs in a stage-2 > + protected context and cannot use the SMMU; mutually exclusive with > + iommus. SCM assignment replaces the buffer's current owners with the > + supplied set, so the driver always adds HLOS to the destination list > + itself to retain host access; HLOS must not be listed here. All > + listed VMIDs and HLOS receive read-write access. > + $ref: /schemas/types.yaml#/definitions/uint32-array > + minItems: 1 > + maxItems: 2 > + uniqueItems: true > + > required: > - compatible > - - iommus > + > +oneOf: > + - required: > + - iommus > + - required: > + - qcom,vmids > + > +dependentRequired: > + memory-region: > + - qcom,vmids > > additionalProperties: false > > @@ -32,3 +73,30 @@ examples: > compatible = "qcom,q6apm-dais"; > iommus = <&apps_smmu 0x1801 0x0>; > }; > + - | > + #include > + > + reserved-memory { > + #address-cells = <2>; > + #size-cells = <2>; > + ranges; > + > + audio_heap_mem: audio-heap@a1000000 { > + compatible = "shared-dma-pool"; > + reg = <0x0 0xa1000000 0x0 0x100000>; > + no-map; > + }; > + > + audio_mdsp_carveout_mem: audio-carveout@a1100000 { > + compatible = "shared-dma-pool"; > + reg = <0x0 0xa1100000 0x0 0x400000>; > + no-map; > + }; > + }; Drop entire node, not really relevant. > + > + dais { > + compatible = "qcom,q6apm-dais"; > + /* index 0: control path, index 1: data path */ > + memory-region = <&audio_heap_mem>, <&audio_mdsp_carveout_mem>; > + qcom,vmids = ; > + }; > Best regards, Krzysztof