[PATCH v17 17/20] iommu/arm-smmu: Add a way for implementations to influence SCTLR

Rob Clark
2020-09-05T20:05:30Z

From: Rob Clark <robdclark@chromium.org>

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 <robdclark@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
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;
+
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;
};
--
2.26.2