[PATCH 2/3] iommu/arm-smmu-qcom: Make set_stall work when the device is on

[Connor Abbott]

Up until now we have only called the set_stall callback during
initialization when the device is off. But we will soon start calling it
to temporarily disable stall-on-fault when the device is on, so handle
that by checking if the device is on and writing SCTLR.

Signed-off-by: Connor Abbott <cwabbott0 at gmail.com>
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 31 +++++++++++++++++++++++++++---
 1 file changed, 28 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 ee2fdf7e79a6d04bc2700e454253c96b573c5569..54be27f7b49d78b7542fd714d6aade2b23c65fc0 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -112,12 +112,37 @@ static void qcom_adreno_smmu_set_stall(const void *cookie, bool enabled)
 {
 	struct arm_smmu_domain *smmu_domain = (void *)cookie;
 	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
-	struct qcom_smmu *qsmmu = to_qcom_smmu(smmu_domain->smmu);
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
+	u32 mask = BIT(cfg->cbndx);
+	bool stall_changed = !!(qsmmu->stall_enabled & mask) != enabled;
 
 	if (enabled)
-		qsmmu->stall_enabled |= BIT(cfg->cbndx);
+		qsmmu->stall_enabled |= mask;
 	else
-		qsmmu->stall_enabled &= ~BIT(cfg->cbndx);
+		qsmmu->stall_enabled &= ~mask;
+
+	/*
+	 * If the device is on and we changed the setting, update the register.
+	 */
+	if (stall_changed && pm_runtime_get_if_active(smmu->dev) > 0) {
+		u32 reg = arm_smmu_cb_read(smmu, cfg->cbndx, ARM_SMMU_CB_SCTLR);
+
+		if (enabled)
+			reg |= ARM_SMMU_SCTLR_CFCFG;
+		else
+			reg &= ~ARM_SMMU_SCTLR_CFCFG;
+
+		arm_smmu_cb_write(smmu, cfg->cbndx, ARM_SMMU_CB_SCTLR, reg);
+
+		/*
+		 * If doing this in the context fault handler, make sure the
+		 * update lands before we acknowledge the fault.
+		 */
+		wmb();
+
+		pm_runtime_put_autosuspend(smmu->dev);
+	}
 }
 
 static void qcom_adreno_smmu_resume_translation(const void *cookie, bool terminate)

-- 
2.47.1