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From: Mark Brown <broonie@kernel.org>
To: Ajay Kumar Nandam <ajay.nandam@oss.qualcomm.com>
Cc: Srinivas Kandagatla <srini@kernel.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
	Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	linux-sound@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	Mohit Sharma <mohit.sharma@oss.qualcomm.com>
Subject: Re: [PATCH v5 4/4] ASoC: qcom: q6apm-dai: add SCM buffer assignment for mDSP platforms
Date: Tue, 22 Sep 2026 14:30:00 +0200	[thread overview]
Message-ID: <arJ0yBdeDfjYihRd@sirena.co.uk> (raw)
In-Reply-To: <20260922-vmid-v4-v5-4-e79cfd7af5b3@oss.qualcomm.com>

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On Tue, Sep 22, 2026 at 12:38:12AM +0530, Ajay Kumar Nandam wrote:
> On platforms such as Qualcomm Shikra, audio is served by the modem DSP
> (mDSP) which runs in a stage-2 protected context. Unlike ADSP targets
> where SMMU-mapped system RAM is directly accessible, the mDSP cannot
> reach the PCM buffers unless they are explicitly SCM-assigned to the
> appropriate Virtual Machine IDs (VMIDs). Without this assignment, audio
> does not function on these platforms.

> +static int q6apm_dai_scm_assign(struct q6apm_dai_data *pdata,
> +				phys_addr_t addr, size_t size)
> +{

> +	r = &pdata->scm_regions[pdata->num_scm_regions++];

This needs a lock.

> @@ -1021,6 +1168,7 @@ static int q6apm_dai_probe(struct platform_device *pdev)
>  {

> +			if (per_stream <= POS_BUFFER_BYTES + PAGE_SIZE) {
> +				dev_err(dev,
> +					"reserved-memory pool too small: %llu bytes\n",
> +					(u64)rmem->size);

%pa

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  reply	other threads:[~2026-09-22 12:30 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-21 19:08 [PATCH v5 0/4] ASoC: qcom: enable audio on stage-2 protected DSPs (mDSP) Ajay Kumar Nandam
2026-09-21 19:08 ` [PATCH v5 1/4] ASoC: qcom: q6apm: clear g_apm on driver removal Ajay Kumar Nandam
2026-09-21 19:08 ` [PATCH v5 2/4] ASoC: qcom: qdsp6: generalize GPR service domain Ajay Kumar Nandam
2026-09-21 19:08 ` [PATCH v5 3/4] dt-bindings: sound: qcom,q6apm-dai: add memory-region and relax iommus Ajay Kumar Nandam
2026-09-22 12:21   ` Mark Brown
2026-09-23 11:08     ` Ajay Kumar Nandam
2026-09-22 12:46   ` Rob Herring (Arm)
2026-09-23 11:12     ` Ajay Kumar Nandam
2026-09-23 11:57   ` Krzysztof Kozlowski
2026-09-23 16:22     ` Ajay Kumar Nandam
2026-09-21 19:08 ` [PATCH v5 4/4] ASoC: qcom: q6apm-dai: add SCM buffer assignment for mDSP platforms Ajay Kumar Nandam
2026-09-22 12:30   ` Mark Brown [this message]
2026-09-23 11:20     ` Ajay Kumar Nandam

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