linux-kernel - Re: [PATCH] iommu/qcom: restore IOMMU state if needed

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Message-ID: <4525320.LvFx2qVVIh@z3ntu.xyz>
Date:   Sat, 25 Nov 2023 13:07:05 +0100
From:   Luca Weiss <luca@...tu.xyz>
To:     ~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org,
        Rob Clark <robdclark@...il.com>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>
Cc:     iommu@...ts.linux.dev, linux-arm-msm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Vladimir Lypak <vladimir.lypak@...il.com>
Subject: Re: [PATCH] iommu/qcom: restore IOMMU state if needed

On Mittwoch, 11. Oktober 2023 19:57:26 CET Luca Weiss wrote:
> From: Vladimir Lypak <vladimir.lypak@...il.com>
> 
> If the IOMMU has a power domain then some state will be lost in
> qcom_iommu_suspend and TZ will reset device if we don't call
> qcom_scm_restore_sec_cfg before accessing it again.
> 
> Signed-off-by: Vladimir Lypak <vladimir.lypak@...il.com>
> [luca@...tu.xyz: reword commit message a bit]
> Signed-off-by: Luca Weiss <luca@...tu.xyz>
> ---
> This patch is required for MSM8953 GPU IOMMU.
> 
> See also downstream sources:
> https://git.codelinaro.org/clo/la/kernel/msm-4.9/-/commit/f8464885dafc5b780b
> 85de29d92a08c692d3a4d0
> https://git.codelinaro.org/clo/la/kernel/msm-4.9/-/blob/LA.UM.10.6.2.r1-025
> 00-89xx.0/drivers/iommu/arm-smmu.c#L4221-4225
> 
> Since the compatibles provided by this driver (qcom,msm-iommu-v*) is
> only used on msm8916, msm8939 and msm8953, and both 8916 and 8939 don't
> have a power domain on the IOMMU, I also don't expect anything to break
> there.

Hi all,

Any feedback on this patch?

Regards
Luca

> ---
>  drivers/iommu/arm/arm-smmu/qcom_iommu.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> b/drivers/iommu/arm/arm-smmu/qcom_iommu.c index 97b2122032b2..67abeb02cf53
> 100644
> --- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> +++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> @@ -900,8 +900,16 @@ static void qcom_iommu_device_remove(struct
> platform_device *pdev) static int __maybe_unused qcom_iommu_resume(struct
> device *dev)
>  {
>  	struct qcom_iommu_dev *qcom_iommu = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = clk_bulk_prepare_enable(CLK_NUM, qcom_iommu->clks);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (dev->pm_domain)
> +		return qcom_scm_restore_sec_cfg(qcom_iommu->sec_id, 0);
> 
> -	return clk_bulk_prepare_enable(CLK_NUM, qcom_iommu->clks);
> +	return ret;
>  }
> 
>  static int __maybe_unused qcom_iommu_suspend(struct device *dev)
> 
> ---
> base-commit: 2933a1156742d8c47550493a77af8e2d81cf3c84
> change-id: 20231011-msm8953-iommu-restore-fabc2e31fee7
> 
> Best regards,