On 08.05.17 15:14:37, Linu Cherian wrote:
> On Sat May 06, 2017 at 12:18:44AM +0200, Robert Richter wrote:
> > On 05.05.17 17:38:06, Geetha sowjanya wrote:
> > > From: Linu Cherian <linu.cher...@cavium.com>
> > > 
> > > With implementations supporting only page 0 register space,
> > > resource size can be 64k as well and hence perform size checks
> > > based on SMMU option PAGE0_REGS_ONLY.
> > > 
> > > For this, arm_smmu_device_dt_probe/acpi_probe has been moved before
> > > platform_get_resource call, so that SMMU options are set beforehand.
> > > 
> > > Signed-off-by:  Linu Cherian <linu.cher...@cavium.com>
> > > Signed-off-by:  Geetha Sowjanya <geethasowjanya.ak...@cavium.com>
> > > ---
> > >  drivers/iommu/arm-smmu-v3.c | 26 +++++++++++++++++---------
> > >  1 file changed, 17 insertions(+), 9 deletions(-)
> > > 
> > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> > > index 107b4a6..f027676 100644
> > > --- a/drivers/iommu/arm-smmu-v3.c
> > > +++ b/drivers/iommu/arm-smmu-v3.c
> > > @@ -2672,6 +2672,14 @@ static int arm_smmu_device_dt_probe(struct 
> > > platform_device *pdev,
> > >   return ret;
> > >  }
> > >  
> > > +static unsigned long arm_smmu_resource_size(struct arm_smmu_device *smmu)
> > > +{
> > > + if (ARM_SMMU_PAGE0_REGS_ONLY(smmu))
> > > +         return SZ_64K;
> > > + else
> > > +         return SZ_128K;
> > > +}
> > > +
> > 
> > I think this can be dropped. See below.
> > 
> > >  static int arm_smmu_device_probe(struct platform_device *pdev)
> > >  {
> > >   int irq, ret;
> > > @@ -2688,9 +2696,17 @@ static int arm_smmu_device_probe(struct 
> > > platform_device *pdev)
> > >   }
> > >   smmu->dev = dev;
> > >  
> > > + if (dev->of_node) {
> > > +         ret = arm_smmu_device_dt_probe(pdev, smmu);
> > > + } else {
> > > +         ret = arm_smmu_device_acpi_probe(pdev, smmu);
> > > +         if (ret == -ENODEV)
> > > +                 return ret;
> > > + }
> > > +
> > >   /* Base address */
> > >   res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > - if (resource_size(res) + 1 < SZ_128K) {
> > > + if (resource_size(res) + 1 < arm_smmu_resource_size(smmu)) {
> > >           dev_err(dev, "MMIO region too small (%pr)\n", res);
> > >           return -EINVAL;
> > >   }
> > 
> > Why not just do the follwoing here:
> > 
> >     /* Base address */
> >     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >     if (resource_size(res) + 1 < arm_smmu_resource_size(smmu)) {
> >             dev_err(dev, "MMIO region too small (%pr)\n", res);
> >             return -EINVAL;
> >     }
> >     ioaddr = res->start;
> > 
> > +   /*
> > +    * Override the size, for Cavium ThunderX2 implementation
> > +    * which doesn't support the page 1 SMMU register space.
> > +    */
> > +   if (smmu->options & ARM_SMMU_OPT_PAGE0_REGS_ONLY)
> > +           res->end = res->size + SZ_64K -1;
> > +
> >     smmu->base = devm_ioremap_resource(dev, res);
> >     if (IS_ERR(smmu->base))
> >             return PTR_ERR(smmu->base);
> 
> 
> This might not work, since platform_device_add is being called from
> iort.c before the res->end gets fixed up here. 

It should. You added it with 128k and you get it back with
platform_get_resource(), but before ioremap you shrink the size to
64k.

-Robert
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