[PATCH 3/7] iommu/arm-smmu: Add tlb_sync implementation hook

[Krishna Reddy <vdumpa@xxxxxxxxxx>]

tlb_sync hook allows nvidia smmu handle tlb sync
across multiple SMMUs as necessary.

Signed-off-by: Krishna Reddy <vdumpa@xxxxxxxxxx>
---
 drivers/iommu/arm-smmu-nvidia.c | 32 ++++++++++++++++++++++++++++++++
 drivers/iommu/arm-smmu.c        |  8 +++++---
 drivers/iommu/arm-smmu.h        |  4 ++++
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm-smmu-nvidia.c b/drivers/iommu/arm-smmu-nvidia.c
index d93ceda..a429b2c 100644
--- a/drivers/iommu/arm-smmu-nvidia.c
+++ b/drivers/iommu/arm-smmu-nvidia.c
@@ -56,11 +56,43 @@ static void nsmmu_write_reg64(struct arm_smmu_device *smmu,
 		writeq_relaxed(val, nsmmu_page(smmu, i, page) + offset);
 }
 
+static void nsmmu_tlb_sync_wait(struct arm_smmu_device *smmu, int page,
+				int sync, int status, int inst)
+{
+	u32 reg;
+	unsigned int spin_cnt, delay;
+
+	for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {
+		for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {
+			reg = readl_relaxed(
+			      nsmmu_page(smmu, inst, page) + status);
+			if (!(reg & sTLBGSTATUS_GSACTIVE))
+				return;
+			cpu_relax();
+		}
+		udelay(delay);
+	}
+	dev_err_ratelimited(smmu->dev,
+			    "TLB sync timed out -- SMMU may be deadlocked\n");
+}
+
+static void nsmmu_tlb_sync(struct arm_smmu_device *smmu, int page,
+			   int sync, int status)
+{
+	int i;
+
+	arm_smmu_writel(smmu, page, sync, 0);
+
+	for (i = 0; i < to_nsmmu(smmu)->num_inst; i++)
+		nsmmu_tlb_sync_wait(smmu, page, sync, status, i);
+}
+
 static const struct arm_smmu_impl nsmmu_impl = {
 	.read_reg = nsmmu_read_reg,
 	.write_reg = nsmmu_write_reg,
 	.read_reg64 = nsmmu_read_reg64,
 	.write_reg64 = nsmmu_write_reg64,
+	.tlb_sync = nsmmu_tlb_sync,
 };
 
 struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 46e1641..f5454e71 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -52,9 +52,6 @@
  */
 #define QCOM_DUMMY_VAL -1
 
-#define TLB_LOOP_TIMEOUT		1000000	/* 1s! */
-#define TLB_SPIN_COUNT			10
-
 #define MSI_IOVA_BASE			0x8000000
 #define MSI_IOVA_LENGTH			0x100000
 
@@ -244,6 +241,11 @@ static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, int page,
 	unsigned int spin_cnt, delay;
 	u32 reg;
 
+	if (smmu->impl->tlb_sync) {
+		smmu->impl->tlb_sync(smmu, page, sync, status);
+		return;
+	}
+
 	arm_smmu_writel(smmu, page, sync, QCOM_DUMMY_VAL);
 	for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {
 		for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index 9645bf1..d3217f1 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -207,6 +207,8 @@ enum arm_smmu_cbar_type {
 /* Maximum number of context banks per SMMU */
 #define ARM_SMMU_MAX_CBS		128
 
+#define TLB_LOOP_TIMEOUT		1000000	/* 1s! */
+#define TLB_SPIN_COUNT			10
 
 /* Shared driver definitions */
 enum arm_smmu_arch_version {
@@ -336,6 +338,8 @@ struct arm_smmu_impl {
 	int (*cfg_probe)(struct arm_smmu_device *smmu);
 	int (*reset)(struct arm_smmu_device *smmu);
 	int (*init_context)(struct arm_smmu_domain *smmu_domain);
+	void (*tlb_sync)(struct arm_smmu_device *smmu, int page, int sync,
+			 int status);
 };
 
 static inline void __iomem *arm_smmu_page(struct arm_smmu_device *smmu, int n)
-- 
2.1.4