[PATCH RFC 2/8] iommu/arm-smmu-v3: Add and use static helper function arm_smmu_cmdq_issue_cmd_with_sync()

[Zhen Lei]

The obvious key to the performance optimization of commit 587e6c10a7ce
("iommu/arm-smmu-v3: Reduce contention during command-queue insertion") is
to allow multiple cores to insert commands in parallel after a brief mutex
contention.

Obviously, inserting as many commands at a time as possible can reduce the
number of times the mutex contention participates, thereby improving the
overall performance. At least it reduces the number of calls to function
arm_smmu_cmdq_issue_cmdlist().

Therefore, function arm_smmu_cmdq_issue_cmd_with_sync() is added to insert
the 'cmd+sync' commands at a time.

Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 33 +++++++++++++--------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 2433d3c29b49ff2..a5361153ca1d6a4 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -858,11 +858,25 @@ static int arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
 	return arm_smmu_cmdq_issue_cmdlist(smmu, cmd, 1, false);
 }
 
-static int arm_smmu_cmdq_issue_sync(struct arm_smmu_device *smmu)
+static int __maybe_unused arm_smmu_cmdq_issue_sync(struct arm_smmu_device *smmu)
 {
 	return arm_smmu_cmdq_issue_cmdlist(smmu, NULL, 0, true);
 }
 
+static int arm_smmu_cmdq_issue_cmd_with_sync(struct arm_smmu_device *smmu,
+					     struct arm_smmu_cmdq_ent *ent)
+{
+	u64 cmd[CMDQ_ENT_DWORDS];
+
+	if (arm_smmu_cmdq_build_cmd(cmd, ent)) {
+		dev_warn(smmu->dev, "ignoring unknown CMDQ opcode 0x%x\n",
+			 ent->opcode);
+		return -EINVAL;
+	}
+
+	return arm_smmu_cmdq_issue_cmdlist(smmu, cmd, 1, true);
+}
+
 static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
 				    struct arm_smmu_cmdq_batch *cmds,
 				    struct arm_smmu_cmdq_ent *cmd)
@@ -928,8 +942,7 @@ void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid)
 		.tlbi.asid = asid,
 	};
 
-	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
-	arm_smmu_cmdq_issue_sync(smmu);
+	arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 }
 
 static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain,
@@ -1210,8 +1223,7 @@ static void arm_smmu_sync_ste_for_sid(struct arm_smmu_device *smmu, u32 sid)
 		},
 	};
 
-	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
-	arm_smmu_cmdq_issue_sync(smmu);
+	arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 }
 
 static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
@@ -1823,8 +1835,7 @@ static void arm_smmu_tlb_inv_context(void *cookie)
 	} else {
 		cmd.opcode	= CMDQ_OP_TLBI_S12_VMALL;
 		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
-		arm_smmu_cmdq_issue_cmd(smmu, &cmd);
-		arm_smmu_cmdq_issue_sync(smmu);
+		arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 	}
 	arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0);
 }
@@ -3338,18 +3349,16 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
 
 	/* Invalidate any cached configuration */
 	cmd.opcode = CMDQ_OP_CFGI_ALL;
-	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
-	arm_smmu_cmdq_issue_sync(smmu);
+	arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 
 	/* Invalidate any stale TLB entries */
 	if (smmu->features & ARM_SMMU_FEAT_HYP) {
 		cmd.opcode = CMDQ_OP_TLBI_EL2_ALL;
-		arm_smmu_cmdq_issue_cmd(smmu, &cmd);
+		arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 	}
 
 	cmd.opcode = CMDQ_OP_TLBI_NSNH_ALL;
-	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
-	arm_smmu_cmdq_issue_sync(smmu);
+	arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
 
 	/* Event queue */
 	writeq_relaxed(smmu->evtq.q.q_base, smmu->base + ARM_SMMU_EVTQ_BASE);
-- 
2.26.0.106.g9fadedd