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SubjectRe: [PATCH v3 2/7] iommu/arm-smmu-v3: Do resource size checks based on SMMU
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.cherian@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.cherian@cavium.com>
> > Signed-off-by: Geetha Sowjanya <geethasowjanya.akula@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.


--
Linu cherian

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