[PATCH 8/8] iommu/arm-smmu: suppress fault information about CMD_PREFETCH_CONFIG execution
From: Will Deacon <hidden>
Date: 2015-06-29 17:49:09
Also in:
linux-iommu
On Fri, Jun 26, 2015 at 09:33:04AM +0100, Zhen Lei wrote:
quoted hunk ↗ jump to hunk
Some broken SMMUv3 devices treat CMD_PREFETCH_CONFIG as illegal command, it's ugly to print error information. CMD_PREFETCH_CONFIG is just used to prefetch the configuration for a specified StreamID, without this command will not impact SMMUv3 function. Signed-off-by: Zhen Lei <redacted> --- drivers/iommu/arm-smmu-v3.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index d799feb..3971aef 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c@@ -813,6 +813,7 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu) }; int i; + u32 opcode; u64 cmd[CMDQ_ENT_DWORDS]; struct arm_smmu_queue *q = &smmu->cmdq.q; u32 cons = readl_relaxed(q->cons_reg);@@ -821,15 +822,14 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu) .opcode = CMDQ_OP_CMD_SYNC, }; - dev_err(smmu->dev, "CMDQ error (cons 0x%08x): %s\n", cons, - cerror_str[idx]); - switch (idx) { case CMDQ_ERR_CERROR_ILL_IDX: break; case CMDQ_ERR_CERROR_ABT_IDX: - dev_err(smmu->dev, "retrying command fetch\n"); case CMDQ_ERR_CERROR_NONE_IDX: + dev_err(smmu->dev, "CMDQ error (cons 0x%08x): %s\n", cons, + cerror_str[idx]); + dev_err(smmu->dev, "retrying command execution\n");
Why are you making this (unrelated) change? Out of interest, did the gerror code manage to turn the prefetch into a SYNC, as intended?
quoted hunk ↗ jump to hunk
return; }@@ -838,10 +838,20 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu) * not to touch any of the shadow cmdq state. */ queue_read(cmd, Q_ENT(q, idx), q->ent_dwords); + + /* + * Some broken SMMUv3 devices treat CMD_PREFETCH_CONFIG as illegal + * command, it's ugly to print error information. + */ + opcode = (cmd[0] >> CMDQ_0_OP_SHIFT) & CMDQ_0_OP_MASK; + if (opcode == CMDQ_OP_PREFETCH_CFG) + goto skip_error_command; +
I think a better way to fix this would be to add a quick to the device-tree along the lines of "hisilicon,broken-prefetch-cmd" which we could check before issuing the prefetch command in arm_smmu_write_strtab_ent. Something along the lines of the arm_smmu_options in arm-smmu.c would be a good basis for quirks. Will