From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Will Deacon <will@kernel.org>,
Akhil P Oommen <akhilpo@codeaurora.org>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Jordan Crouse <jcrouse@codeaurora.org>,
linux-arm-msm@vger.kernel.org,
Robin Murphy <robin.murphy@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv2 2/2] iommu/arm-smmu-qcom: Move the adreno smmu specific impl earlier
Date: Fri, 26 Feb 2021 11:24:52 -0600 [thread overview]
Message-ID: <YDku5PFQZetP4iG8@builder.lan> (raw)
In-Reply-To: <c607d71eb0fe507c8b83cc0ea9b393777f22149a.1614332994.git.saiprakash.ranjan@codeaurora.org>
On Fri 26 Feb 03:55 CST 2021, Sai Prakash Ranjan wrote:
> Adreno(GPU) SMMU and APSS(Application Processor SubSystem) SMMU
> both implement "arm,mmu-500" in some QTI SoCs and to run through
> adreno smmu specific implementation such as enabling split pagetables
> support, we need to match the "qcom,adreno-smmu" compatible first
> before apss smmu or else we will be running apps smmu implementation
> for adreno smmu and the additional features for adreno smmu is never
> set. For ex: we have "qcom,sc7280-smmu-500" compatible for both apps
> and adreno smmu implementing "arm,mmu-500", so the adreno smmu
> implementation is never reached because the current sequence checks
> for apps smmu compatible(qcom,sc7280-smmu-500) first and runs that
> specific impl and we never reach adreno smmu specific implementation.
>
So you're saying that you have a single SMMU instance that's compatible
with both an entry in qcom_smmu_impl_of_match[] and "qcom,adreno-smmu"?
Per your proposed change we will pick the adreno ops _only_ for this
component, essentially disabling the non-Adreno quirks selected by the
qcom impl. As such keeping the non-adreno compatible in the
qcom_smmu_impl_init[] seems to only serve to obfuscate the situation.
Don't we somehow need the combined set of quirks? (At least if we're
running this with a standard UEFI based boot flow?)
Regards,
Bjorn
> Suggested-by: Akhil P Oommen <akhilpo@codeaurora.org>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
> drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index bea3ee0dabc2..03f048aebb80 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -345,11 +345,17 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
> {
> const struct device_node *np = smmu->dev->of_node;
>
> - if (of_match_node(qcom_smmu_impl_of_match, np))
> - return qcom_smmu_create(smmu, &qcom_smmu_impl);
> -
> + /*
> + * Do not change this order of implementation, i.e., first adreno
> + * smmu impl and then apss smmu since we can have both implementing
> + * arm,mmu-500 in which case we will miss setting adreno smmu specific
> + * features if the order is changed.
> + */
> if (of_device_is_compatible(np, "qcom,adreno-smmu"))
> return qcom_smmu_create(smmu, &qcom_adreno_smmu_impl);
>
> + if (of_match_node(qcom_smmu_impl_of_match, np))
> + return qcom_smmu_create(smmu, &qcom_smmu_impl);
> +
> return smmu;
> }
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
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next prev parent reply other threads:[~2021-02-26 17:25 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 9:55 [PATCHv2 0/2] iommu/arm-smmu-qcom: Add SC7280 support Sai Prakash Ranjan
2021-02-26 9:55 ` [PATCHv2 1/2] iommu/arm-smmu-qcom: Add SC7280 SMMU compatible Sai Prakash Ranjan
2021-02-26 9:55 ` [PATCHv2 2/2] iommu/arm-smmu-qcom: Move the adreno smmu specific impl earlier Sai Prakash Ranjan
2021-02-26 15:51 ` Jordan Crouse
2021-02-26 17:24 ` Bjorn Andersson [this message]
2021-02-26 18:23 ` Rob Clark
2021-02-26 19:14 ` Bjorn Andersson
2021-02-27 13:53 ` Sai Prakash Ranjan
2021-03-11 23:29 ` Bjorn Andersson
2021-03-14 19:01 ` Sai Prakash Ranjan
2021-03-25 7:40 ` Sai Prakash Ranjan
2021-03-25 15:05 ` Will Deacon
2021-04-05 8:42 ` Sai Prakash Ranjan
2021-04-19 3:11 ` Sai Prakash Ranjan
2021-02-26 18:48 ` Jordan Crouse
2021-02-26 19:54 ` Jordan Crouse
2021-04-19 14:38 ` Bjorn Andersson
2021-04-20 6:06 ` Sai Prakash Ranjan
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