> -----Original Message----- > From: Lorenzo Pieralisi [mailto:[email protected]] > Sent: Friday, June 16, 2017 12:17 PM > To: Shameerali Kolothum Thodi > Cc: [email protected]; [email protected]; Linuxarm; linux- > [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected] > Subject: Re: [PATCH 2/2] iommu/arm-smmu-v3:Enable ACPI based HiSilicon > erratum 161010801 > > On Fri, Jun 16, 2017 at 09:43:52AM +0000, Shameerali Kolothum Thodi wrote: > > Hi Lorenzo, > > > > > -----Original Message----- > > > From: [email protected] [mailto:linuxarm- > > > [email protected]] On Behalf Of Shameerali Kolothum Thodi > > > Sent: Tuesday, June 13, 2017 3:53 PM > > > To: Lorenzo Pieralisi > > > Cc: [email protected]; [email protected]; Linuxarm; linux- > > > [email protected]; [email protected]; > > > [email protected]; [email protected]; > [email protected]; > > > [email protected]; [email protected] > > > 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(®ion->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 { > > The fwnode handling is fine, I do not like much the: > > dev_is_pci() > > check because it relies on implicit knowledge of the platform and > the quirks you need (ie you know that it is _just_ a PCI RC quirk > implicitly), the logic behind reserving the regions is a bit > convoluted and not easy to understand at all. > > Let me try to rephrase it: you know, through an SMMU model number, > that your PCI RC handles MSI in a specific way, but by reading the > code above this is not clear at all, at least to me. This is a PCI > RC quirk but it does not depend on any PCI RC specific firmware binding > whatsoever, that's what is a bit hard to understand.
Right. I had a thought of limiting the iort_iommu_its_get_resv_regions to pci devices only. Just like the way iommu_dma_get_resv_regions() does now. But not sure there will ever be a platform which requires this for non-pci devices as well. Thanks, Shameer _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
