[PATCH] iommu/arm-smmu: Clear global and context bank fault status registers

[Will Deacon]

On Mon, Sep 30, 2013 at 02:56:21PM +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 <andreas.herrmann at calxeda.com>
> ---
>  drivers/iommu/arm-smmu.c |   27 ++++++++++++++++++++-------
>  1 file changed, 20 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 579b6f8..cbbf597 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -631,6 +631,12 @@ static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
>  	return IRQ_HANDLED;
>  }
>  
> +static void arm_smmu_clear_cb_fsr(struct arm_smmu_device *smmu, u8 cbndx)
> +{
> +	void __iomem *cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cbndx);
> +	writel_relaxed(FSR_FAULT, cb_base + ARM_SMMU_CB_FSR);
> +}

Hmm, why not just stick this in arm_smmu_init_context_bank...

>  static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain)
>  {
>  	u32 reg;
> @@ -838,6 +844,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
>  		root_cfg->irptndx = root_cfg->cbndx;
>  	}
>  
> +	arm_smmu_clear_cb_fsr(smmu, root_cfg->cbndx);

... then move that function call here instead of where it currently is?

>  	irq = smmu->irqs[smmu->num_global_irqs + root_cfg->irptndx];
>  	ret = request_irq(irq, arm_smmu_context_fault, IRQF_SHARED,
>  			  "arm-smmu-context-fault", domain);
> @@ -1564,7 +1571,11 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
>  	void __iomem *gr0_base = ARM_SMMU_GR0(smmu);
>  	void __iomem *sctlr_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB_SCTLR;
>  	int i = 0;
> -	u32 scr0 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sCR0);
> +	u32 val;

I guess we have to dilute the meaning of the variable, but perhaps `reg' is
slightly more indicative than `val'?

Do you plan to post all your patches as a new series (it's hard to keep
track of what to pick)?

Cheers,

Will