[PATCH 3/6] iommu/qcom: Properly reset the IOMMU context

Konrad Dybcio
2022-05-27T21:39:05Z

From: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>

To avoid context faults reset the context entirely on detach and
to ensure a fresh clean start also do a complete reset before
programming the context for domain initialization.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
---
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 75f353866c40..129e322f56a6 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -223,6 +223,23 @@ 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, 0);
+ 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);
+
+ /* Should we issue a TLBSYNC there instead? */
+ wmb();
+}
+
static int qcom_iommu_init_domain(struct iommu_domain *domain,
struct qcom_iommu_dev *qcom_iommu,
struct device *dev)
@@ -273,6 +290,8 @@ static int qcom_iommu_init_domain(struct iommu_domain *domain,
ctx->secure_init = true;
}

+ qcom_iommu_reset_ctx(ctx);
+
/* TCR */
iommu_writel(ctx, ARM_SMMU_CB_TCR2,
arm_smmu_lpae_tcr2(&pgtbl_cfg));
@@ -406,8 +425,8 @@ 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;
}
--
2.36.1