iommu/arm-smmu-v3: Add and use static helper function arm_smmu_get_cmdq()

One SMMU has only one normal CMDQ. Therefore, this CMDQ is used regardless
of the core on which the command is inserted. It can be referenced
directly through "smmu->cmdq". However, one SMMU has multiple ECMDQs, and
the ECMDQ used by the core on which the command insertion is executed may
be different. So the helper function arm_smmu_get_cmdq() is added, which
returns the CMDQ/ECMDQ that the current core should use. Currently, the
code that supports ECMDQ is not added. just simply returns "&smmu->cmdq".

Many subfunctions of arm_smmu_cmdq_issue_cmdlist() use "&smmu->cmdq" or
"&smmu->cmdq.q" directly. To support ECMDQ, they need to call the newly
added function arm_smmu_get_cmdq() instead.

Note that normal CMDQ is still required until ECMDQ is available.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210811114852.2429-4-thunder.leizhen@huawei.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -335,10 +335,14 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
 	return 0;
 }
 
+static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu)
+{
+	return &smmu->cmdq;
+}
+
 static void arm_smmu_cmdq_build_sync_cmd(u64 *cmd, struct arm_smmu_device *smmu,
-					 u32 prod)
+					 struct arm_smmu_queue *q, u32 prod)
 {
-	struct arm_smmu_queue *q = &smmu->cmdq.q;
 	struct arm_smmu_cmdq_ent ent = {
 		.opcode = CMDQ_OP_CMD_SYNC,
 	};
@@ -579,7 +583,7 @@ static int arm_smmu_cmdq_poll_until_not_full(struct arm_smmu_device *smmu,
 {
 	unsigned long flags;
 	struct arm_smmu_queue_poll qp;
-	struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
+	struct arm_smmu_cmdq *cmdq = arm_smmu_get_cmdq(smmu);
 	int ret = 0;
 
 	/*
@@ -595,7 +599,7 @@ static int arm_smmu_cmdq_poll_until_not_full(struct arm_smmu_device *smmu,
 
 	queue_poll_init(smmu, &qp);
 	do {
-		llq->val = READ_ONCE(smmu->cmdq.q.llq.val);
+		llq->val = READ_ONCE(cmdq->q.llq.val);
 		if (!queue_full(llq))
 			break;
 
@@ -614,7 +618,7 @@ static int __arm_smmu_cmdq_poll_until_msi(struct arm_smmu_device *smmu,
 {
 	int ret = 0;
 	struct arm_smmu_queue_poll qp;
-	struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
+	struct arm_smmu_cmdq *cmdq = arm_smmu_get_cmdq(smmu);
 	u32 *cmd = (u32 *)(Q_ENT(&cmdq->q, llq->prod));
 
 	queue_poll_init(smmu, &qp);
@@ -637,12 +641,12 @@ static int __arm_smmu_cmdq_poll_until_consumed(struct arm_smmu_device *smmu,
 					       struct arm_smmu_ll_queue *llq)
 {
 	struct arm_smmu_queue_poll qp;
-	struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
+	struct arm_smmu_cmdq *cmdq = arm_smmu_get_cmdq(smmu);
 	u32 prod = llq->prod;
 	int ret = 0;
 
 	queue_poll_init(smmu, &qp);
-	llq->val = READ_ONCE(smmu->cmdq.q.llq.val);
+	llq->val = READ_ONCE(cmdq->q.llq.val);
 	do {
 		if (queue_consumed(llq, prod))
 			break;
@@ -732,7 +736,7 @@ static int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
 	u32 prod;
 	unsigned long flags;
 	bool owner;
-	struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
+	struct arm_smmu_cmdq *cmdq = arm_smmu_get_cmdq(smmu);
 	struct arm_smmu_ll_queue llq, head;
 	int ret = 0;
 
@@ -772,7 +776,7 @@ static int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
 	arm_smmu_cmdq_write_entries(cmdq, cmds, llq.prod, n);
 	if (sync) {
 		prod = queue_inc_prod_n(&llq, n);
-		arm_smmu_cmdq_build_sync_cmd(cmd_sync, smmu, prod);
+		arm_smmu_cmdq_build_sync_cmd(cmd_sync, smmu, &cmdq->q, prod);
 		queue_write(Q_ENT(&cmdq->q, prod), cmd_sync, CMDQ_ENT_DWORDS);
 
 		/*