From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 8/8] iommu/arm-smmu: suppress fault information about CMD_PREFETCH_CONFIG execution Date: Mon, 29 Jun 2015 18:49:09 +0100 Message-ID: <20150629174909.GN17474@arm.com> References: <1435307584-9812-1-git-send-email-thunder.leizhen@huawei.com> <1435307584-9812-9-git-send-email-thunder.leizhen@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1435307584-9812-9-git-send-email-thunder.leizhen-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Zhen Lei Cc: "huxinwei-hv44wF8Li93QT0dZR+AlfA@public.gmane.org" , iommu , Zefan Li , Tianhong Ding , linux-arm-kernel List-Id: iommu@lists.linux-foundation.org On Fri, Jun 26, 2015 at 09:33:04AM +0100, Zhen Lei wrote: > 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 > --- > 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? > 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