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

From: John Garry
Date: Wed Aug 11 2021 - 07:15:57 EST



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;
Are any of the errors returned from the "issue command" functions actually
consumed? I couldn't see it on mainline code from a brief browse.
I don't think so.

I don't think so either.

Can we actually propagate them?

There does appear to be some places, here's one I found:

arm_smmu_page_response() -> arm_smmu_cmdq_issue_cmd(), and arm_smmu_page_response is set to arm_smmu_ops.page_response, which returns an int

Thanks,
John