[PATCH 2/5] iommu/arm-smmu-qcom: Provide way to access current TTBR0

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@chromium.org>

The drm driver can skip tlbinv when unmapping from something that isn't
the current pgtables, as there is already a tlbinv on context switch.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 9 +++++++++
 include/linux/adreno-smmu-priv.h           | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 7820711c4560..59b460c1c9a5 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -157,6 +157,14 @@ static int qcom_adreno_smmu_set_ttbr0_cfg(const void *cookie,
 	return 0;
 }
 
+static u64 qcom_adreno_smmu_get_ttbr0(const void *cookie)
+{
+	struct arm_smmu_domain *smmu_domain = (void *)cookie;
+	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+
+	return arm_smmu_cb_readq(smmu_domain->smmu, cfg->cbndx, ARM_SMMU_CB_TTBR0);
+}
+
 static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
 					       struct arm_smmu_device *smmu,
 					       struct device *dev, int start)
@@ -217,6 +225,7 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 	priv->cookie = smmu_domain;
 	priv->get_ttbr1_cfg = qcom_adreno_smmu_get_ttbr1_cfg;
 	priv->set_ttbr0_cfg = qcom_adreno_smmu_set_ttbr0_cfg;
+	priv->get_ttbr0 = qcom_adreno_smmu_get_ttbr0;
 	priv->get_fault_info = qcom_adreno_smmu_get_fault_info;
 	priv->set_stall = qcom_adreno_smmu_set_stall;
 	priv->resume_translation = qcom_adreno_smmu_resume_translation;
diff --git a/include/linux/adreno-smmu-priv.h b/include/linux/adreno-smmu-priv.h
index ac4c2c0ab724..4ad90541a095 100644
--- a/include/linux/adreno-smmu-priv.h
+++ b/include/linux/adreno-smmu-priv.h
@@ -43,6 +43,7 @@ struct adreno_smmu_fault_info {
  * @set_ttbr0_cfg: Set the TTBR0 config for the GPUs context bank.  A
  *                 NULL config disables TTBR0 translation, otherwise
  *                 TTBR0 translation is enabled with the specified cfg
+ * @get_ttbr0:     Get current TTBR0 value
  * @get_fault_info: Called by the GPU fault handler to get information about
  *                  the fault
  * @set_stall:     Configure whether stall on fault (CFCFG) is enabled.  Call
@@ -64,6 +65,7 @@ struct adreno_smmu_priv {
 	const void *cookie;
 	const struct io_pgtable_cfg *(*get_ttbr1_cfg)(const void *cookie);
 	int (*set_ttbr0_cfg)(const void *cookie, const struct io_pgtable_cfg *cfg);
+	u64 (*get_ttbr0)(const void *cookie);
 	void (*get_fault_info)(const void *cookie, struct adreno_smmu_fault_info *info);
 	void (*set_stall)(const void *cookie, bool enabled);
 	void (*resume_translation)(const void *cookie, bool terminate);
-- 
2.37.2