From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 5/9] iommu/arm-smmu: Clear global and context bank fault status registers Date: Fri, 27 Sep 2013 09:52:56 +0100 Message-ID: <20130927085255.GC8319@mudshark.cambridge.arm.com> References: <1380234982-1677-1-git-send-email-andreas.herrmann@calxeda.com> <1380234982-1677-6-git-send-email-andreas.herrmann@calxeda.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1380234982-1677-6-git-send-email-andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@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: Andreas Herrmann Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , Rob Herring , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: iommu@lists.linux-foundation.org On Thu, Sep 26, 2013 at 11:36:17PM +0100, Andreas Herrmann wrote: > After reset these registers have unknown values. > This might cause problems when evaluating SMMU_GFSR and/or SMMU_CB_FSR > in handlers for combined interrupts. > > Signed-off-by: Andreas Herrmann > --- > drivers/iommu/arm-smmu.c | 6 ++++++ > 1 file changed, 6 insertions(+) Your capitalisation of fsr vs FSR is inconsistent > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index de9dd60..9d31ad9 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -642,6 +642,9 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain) > stage1 = root_cfg->cbar != CBAR_TYPE_S2_TRANS; > cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, root_cfg->cbndx); > > + /* clear fsr */ > + writel_relaxed(0xffffffff, cb_base + ARM_SMMU_CB_FSR); I think this is too late, since we've already requested the IRQ line for this context bank by the time we get here. There are two options (afaict): (1) Clear the CB FSRs during probe *and* during domain destruction (2) Delay request_irq until after the context bank has been initialised Also, rather than 0xffffffff, FSR_IGN | FSR_FAULT is probably clearer. > /* CBAR */ > reg = root_cfg->cbar; > if (smmu->version == 1) > @@ -1564,6 +1567,9 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu) > int i = 0; > u32 scr0 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sCR0); > > + /* clear global FSRs */ > + writel(0xffffffff, gr0_base + ARM_SMMU_GR0_sGFSR); For this guy, a read of the register and a write back is probably better than writing 1s to all the reserved bits. Will