Re: [PATCH v18 2/4] iommu/arm-smmu: Add a way for implementations to influence SCTLR
From: Jordan Crouse <hidden>
Date: 2020-11-03 17:28:35
Also in:
linux-arm-msm, linux-iommu, lkml
On Mon, Nov 02, 2020 at 06:18:45PM +0000, Robin Murphy wrote:
On 2020-11-02 17:14, Jordan Crouse wrote:quoted
From: Rob Clark <redacted> For the Adreno GPU's SMMU, we want SCTLR.HUPCF set to ensure that pending translations are not terminated on iova fault. Otherwise a terminated CP read could hang the GPU by returning invalid command-stream data. Signed-off-by: Rob Clark <redacted> Reviewed-by: Bjorn Andersson <redacted> Signed-off-by: Jordan Crouse <redacted> --- drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 6 ++++++ drivers/iommu/arm/arm-smmu/arm-smmu.c | 3 +++ drivers/iommu/arm/arm-smmu/arm-smmu.h | 3 +++ 3 files changed, 12 insertions(+)diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c index 1e942eed2dfc..0663d7d26908 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c@@ -129,6 +129,12 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain, (smmu_domain->cfg.fmt == ARM_SMMU_CTX_FMT_AARCH64)) pgtbl_cfg->quirks |= IO_PGTABLE_QUIRK_ARM_TTBR1; + /* + * On the GPU device we want to process subsequent transactions after a + * fault to keep the GPU from hanging + */ + smmu_domain->cfg.sctlr_set |= ARM_SMMU_SCTLR_HUPCF; + /* * Initialize private interface with GPU: */diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index dad7fa86fbd4..1f06ab219819 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c@@ -617,6 +617,9 @@ void arm_smmu_write_context_bank(struct arm_smmu_device *smmu, int idx) if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) reg |= ARM_SMMU_SCTLR_E; + reg |= cfg->sctlr_set; + reg &= ~cfg->sctlr_clr;Since we now have a write_s2cr hook, I'm inclined to think that the consistency of a write_sctlr hook that could similarly apply its own arbitrary tweaks would make sense for this. Does anyone have any strong opinions?
None from me. That would make an eventual stall-on-fault implementation easier too. Jordan
Robin.quoted
+ arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_SCTLR, reg); }diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h index 6c5ff9999eae..ddf2ca4c923d 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h@@ -144,6 +144,7 @@ enum arm_smmu_cbar_type { #define ARM_SMMU_CB_SCTLR 0x0 #define ARM_SMMU_SCTLR_S1_ASIDPNE BIT(12) #define ARM_SMMU_SCTLR_CFCFG BIT(7) +#define ARM_SMMU_SCTLR_HUPCF BIT(8) #define ARM_SMMU_SCTLR_CFIE BIT(6) #define ARM_SMMU_SCTLR_CFRE BIT(5) #define ARM_SMMU_SCTLR_E BIT(4)@@ -341,6 +342,8 @@ struct arm_smmu_cfg { u16 asid; u16 vmid; }; + u32 sctlr_set; /* extra bits to set in SCTLR */ + u32 sctlr_clr; /* bits to mask in SCTLR */ enum arm_smmu_cbar_type cbar; enum arm_smmu_context_fmt fmt; };
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