[PATCH 2/2] iommu/arm-smmu-v3:Enable ACPI based HiSilicon erratum 161010801

[Shameerali Kolothum Thodi]

Hi Lorenzo,

> -----Original Message-----
> From: linuxarm-bounces at huawei.com [mailto:linuxarm-
> bounces at huawei.com] On Behalf Of Shameerali Kolothum Thodi
> Sent: Tuesday, June 13, 2017 3:53 PM
> To: Lorenzo Pieralisi
> Cc: marc.zyngier at arm.com; will.deacon at arm.com; Linuxarm; linux-
> acpi at vger.kernel.org; iommu at lists.linux-foundation.org;
> hanjun.guo at linaro.org; sudeep.holla at arm.com; robin.murphy at arm.com;
> linux-arm-kernel at lists.infradead.org; devel at acpica.org
> Subject: RE: [PATCH 2/2] iommu/arm-smmu-v3:Enable ACPI based HiSilicon
> erratum 161010801

[...]
 > > > ---
> > >  drivers/iommu/arm-smmu-v3.c | 27 ++++++++++++++++++++++-----
> > >  1 file changed, 22 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-
> > v3.c
> > > index abe4b88..2636c85 100644
> > > --- a/drivers/iommu/arm-smmu-v3.c
> > > +++ b/drivers/iommu/arm-smmu-v3.c
> > > @@ -597,6 +597,7 @@ struct arm_smmu_device {
> > >  	u32				features;
> > >
> > >  #define ARM_SMMU_OPT_SKIP_PREFETCH	(1 << 0)
> > > +#define ARM_SMMU_OPT_RESV_HW_MSI	(1 << 1)
> > >  	u32				options;
> > >
> > >  	struct arm_smmu_cmdq		cmdq;
> > > @@ -1904,14 +1905,29 @@ static void
> arm_smmu_get_resv_regions(struct
> > device *dev,
> > >  				      struct list_head *head)
> > >  {
> > >  	struct iommu_resv_region *region;
> > > +	struct arm_smmu_device *smmu;
> > > +	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> > >  	int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
> > >
> > > -	region = iommu_alloc_resv_region(MSI_IOVA_BASE,
> > MSI_IOVA_LENGTH,
> > > -					 prot, IOMMU_RESV_SW_MSI);
> > > -	if (!region)
> > > -		return;
> > > +	smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
> > >
> > > -	list_add_tail(&region->list, head);
> > > +	if (smmu && (smmu->options & ARM_SMMU_OPT_RESV_HW_MSI)
> > &&
> > > +		      dev_is_pci(dev)) {
> > > +		int ret;
> > > +
> > > +		ret = iort_iommu_its_get_resv_regions(dev, head);
> >
> > This should be made fwnode dependent, it makes precious little sense to
> call
> > IORT to reserve regions on a DT based platforms (I know the
> > ARM_SMMU_OPT_RESV_HW_MSI option is only selected in ACPI (?) but
> > comment applies regardless - have you prototyped a DT version too ?).
> 
> Ok. I will add a check here. 

This is what I have in mind. Please take a look and let me know. I will send out
a v2 of this series soon.
....
if (smmu && (smmu->options & ARM_SMMU_OPT_RESV_HW_MSI) &&
			dev_is_pci(dev)) {
	int ret = -EINVAL;

	if (!is_of_node(smmu->dev->fwnode))
		ret = iort_iommu_its_get_resv_regions(dev, head);

	if (ret) {
		dev_warn(dev, "HW MSI region resv failed: %d\n", ret);
		return;
	}
} else {
---
Many thanks,
Shameer