On 15/11/2022 12:11, AngeloGioacchino Del Regno wrote:
Avoid context faults by resetting the context(s) entirely at
detach_dev() time and also do the same before programming the
context for domain initialization.
Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
[Marijn: Rebased over next-20221111]
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Probably:
Fixes: 0ae349a0f33f ("iommu/qcom: Add qcom_iommu")
What causes context faults? Shouldn't the context be disabled once we
write 0 to CB_SCTLR?
---
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 491a8093f3d6..49f4308f1bd2 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -223,6 +223,20 @@ static irqreturn_t qcom_iommu_fault(int irq, void *dev)
return IRQ_HANDLED;
}
+static void qcom_iommu_reset_ctx(struct qcom_iommu_ctx *ctx)
+{
+ iommu_writel(ctx, ARM_SMMU_CB_FAR, 0);
+ iommu_writel(ctx, ARM_SMMU_CB_FSR, ARM_SMMU_FSR_FAULT);
+ iommu_writel(ctx, ARM_SMMU_CB_S1_MAIR1, 0);
+ iommu_writel(ctx, ARM_SMMU_CB_PAR, 0);
+ iommu_writel(ctx, ARM_SMMU_CB_S1_MAIR0, 0);
+ iommu_writel(ctx, ARM_SMMU_CB_SCTLR, 0);
+ iommu_writel(ctx, ARM_SMMU_CB_TCR2, 0);
+ iommu_writel(ctx, ARM_SMMU_CB_TCR, 0);
+ iommu_writeq(ctx, ARM_SMMU_CB_TTBR0, 0);
+ iommu_writeq(ctx, ARM_SMMU_CB_TTBR1, 0);
+}
+
static int qcom_iommu_init_domain(struct iommu_domain *domain,
struct qcom_iommu_dev *qcom_iommu,
struct device *dev)
@@ -273,6 +287,8 @@ static int qcom_iommu_init_domain(struct iommu_domain *domain,
ctx->secure_init = true;
}
+ qcom_iommu_reset_ctx(ctx);
Is it enough to write 0 to ARM_SMMU_CB_SCTLR here instead of doing the
full reset?
+
/* TTBRs */
iommu_writeq(ctx, ARM_SMMU_CB_TTBR0,
pgtbl_cfg.arm_lpae_s1_cfg.ttbr |
@@ -401,8 +417,8 @@ static void qcom_iommu_detach_dev(struct iommu_domain *domain, struct device *de
for (i = 0; i < fwspec->num_ids; i++) {
struct qcom_iommu_ctx *ctx = to_ctx(qcom_domain, fwspec->ids[i]);
- /* Disable the context bank: */
- iommu_writel(ctx, ARM_SMMU_CB_SCTLR, 0);
+ /* Disable and reset the context bank */
+ qcom_iommu_reset_ctx(ctx);
ctx->domain = NULL;
}
--
With best wishes
Dmitry
