iommu/arm-smmu-v3: Add ARM_SMMU_OPT_TEGRA241_CMDQV

The CMDQV extension in NVIDIA Tegra241 SoC only supports CS_NONE in the
CS field of CMD_SYNC. Add a new SMMU option to accommodate that.

Suggested-by: Will Deacon <will@kernel.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Link: https://lore.kernel.org/r/a3cb9bb2429fbae4a59f7ef517614d226763d717.1724970714.git.nicolinc@nvidia.com
Signed-off-by: Will Deacon <will@kernel.org>

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

@@ -351,6 +351,15 @@ static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu)
 	return &smmu->cmdq;
 }
 
+static bool arm_smmu_cmdq_needs_busy_polling(struct arm_smmu_device *smmu,
+					     struct arm_smmu_cmdq *cmdq)
+{
+	if (cmdq == &smmu->cmdq)
+		return false;
+
+	return smmu->options & ARM_SMMU_OPT_TEGRA241_CMDQV;
+}
+
 static void arm_smmu_cmdq_build_sync_cmd(u64 *cmd, struct arm_smmu_device *smmu,
 					 struct arm_smmu_cmdq *cmdq, u32 prod)
 {
@@ -369,6 +378,8 @@ static void arm_smmu_cmdq_build_sync_cmd(u64 *cmd, struct arm_smmu_device *smmu,
 	}
 
 	arm_smmu_cmdq_build_cmd(cmd, &ent);
+	if (arm_smmu_cmdq_needs_busy_polling(smmu, cmdq))
+		u64p_replace_bits(cmd, CMDQ_SYNC_0_CS_NONE, CMDQ_SYNC_0_CS);
 }
 
 void __arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu,
@@ -423,6 +434,8 @@ void __arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu,
 
 	/* Convert the erroneous command into a CMD_SYNC */
 	arm_smmu_cmdq_build_cmd(cmd, &cmd_sync);
+	if (arm_smmu_cmdq_needs_busy_polling(smmu, cmdq))
+		u64p_replace_bits(cmd, CMDQ_SYNC_0_CS_NONE, CMDQ_SYNC_0_CS);
 
 	queue_write(Q_ENT(q, cons), cmd, q->ent_dwords);
 }
@@ -706,7 +719,8 @@ static int arm_smmu_cmdq_poll_until_sync(struct arm_smmu_device *smmu,
 					 struct arm_smmu_cmdq *cmdq,
 					 struct arm_smmu_ll_queue *llq)
 {
-	if (smmu->options & ARM_SMMU_OPT_MSIPOLL)
+	if (smmu->options & ARM_SMMU_OPT_MSIPOLL &&
+	    !arm_smmu_cmdq_needs_busy_polling(smmu, cmdq))
 		return __arm_smmu_cmdq_poll_until_msi(smmu, cmdq, llq);
 
 	return __arm_smmu_cmdq_poll_until_consumed(smmu, cmdq, llq);

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

@@ -665,6 +665,7 @@ struct arm_smmu_device {
 #define ARM_SMMU_OPT_PAGE0_REGS_ONLY	(1 << 1)
 #define ARM_SMMU_OPT_MSIPOLL		(1 << 2)
 #define ARM_SMMU_OPT_CMDQ_FORCE_SYNC	(1 << 3)
+#define ARM_SMMU_OPT_TEGRA241_CMDQV	(1 << 4)
 	u32				options;
 
 	struct arm_smmu_cmdq		cmdq;