On Tue, Aug 23, 2016 at 08:05:15PM +0100, Robin Murphy wrote: > Introduce a common structure to hold the per-device firmware data that > non-architectural IOMMU drivers generally need to keep track of. > Initially this is DT-specific to complement the existing of_iommu > support code, but will generalise further once other firmware methods > (e.g. ACPI IORT) come along. > > Ultimately the aim is to promote the fwspec to a first-class member of > struct device, and handle the init/free automatically in the firmware > code. That way we can have API calls look for dev->fwspec->iommu_ops > before falling back to dev->bus->iommu_ops, and thus gracefully handle > those troublesome multi-IOMMU systems which we currently cannot. To > start with, though, make use of the existing archdata field and delegate > the init/free to drivers to allow an incremental conversion rather than > the impractical pain of trying to attempt everything in one go. > > Suggested-by: Will Deacon <[email protected]> > Signed-off-by: Robin Murphy <[email protected]> > --- > > v5: Fix shocking num_ids oversight. > > drivers/iommu/of_iommu.c | 52 > ++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/of_iommu.h | 15 ++++++++++++++ > 2 files changed, 67 insertions(+) > > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c > index 1a65cc806898..bec51eb47b0d 100644 > --- a/drivers/iommu/of_iommu.c > +++ b/drivers/iommu/of_iommu.c > @@ -219,3 +219,55 @@ static int __init of_iommu_init(void) > return 0; > } > postcore_initcall_sync(of_iommu_init); > + > +int iommu_fwspec_init(struct device *dev, struct device_node *iommu_np) > +{ > + struct iommu_fwspec *fwspec = dev->archdata.iommu; > + > + if (fwspec) > + return 0; > + > + fwspec = kzalloc(sizeof(*fwspec), GFP_KERNEL); > + if (!fwspec) > + return -ENOMEM; > + > + fwspec->iommu_np = of_node_get(iommu_np); > + fwspec->iommu_ops = of_iommu_get_ops(iommu_np); > + dev->archdata.iommu = fwspec; > + return 0; > +} > + > +void iommu_fwspec_free(struct device *dev) > +{ > + struct iommu_fwspec *fwspec = dev->archdata.iommu; > + > + if (fwspec) { > + of_node_put(fwspec->iommu_np); > + kfree(fwspec); > + } > +} > + > +int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids) > +{ > + struct iommu_fwspec *fwspec = dev->archdata.iommu; > + size_t size; > + > + if (!fwspec) > + return -EINVAL; > + > + size = offsetof(struct iommu_fwspec, ids[fwspec->num_ids + num_ids]); > + fwspec = krealloc(dev->archdata.iommu, size, GFP_KERNEL); > + if (!fwspec) > + return -ENOMEM; > + > + while (num_ids--) > + fwspec->ids[fwspec->num_ids++] = *ids++; > + > + dev->archdata.iommu = fwspec;
It might just be me, but I find this really fiddly to read. The fact that you realloc the whole fwspec, rather than just the array isn't helping, but I also think that while loop would be much better off as a for loop, using the index as, well, an index into the ids array and fwspec->ids array. Will _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
