On Thursday 04 December 2014 10:21:27 Will Deacon wrote: > On Thu, Dec 04, 2014 at 10:10:17AM +0000, Arnd Bergmann wrote: > > On Thursday 04 December 2014 09:49:53 Will Deacon wrote: > > > On Wed, Dec 03, 2014 at 07:57:50PM +0000, Arnd Bergmann wrote: > > > > On Tuesday 02 December 2014 14:16:57 Grant Likely wrote: > > > > > On Mon, Dec 1, 2014 at 11:54 PM, Rob Herring <robherri...@gmail.com> > > > > > wrote: > > > > > > On Mon, Dec 1, 2014 at 10:57 AM, Will Deacon <will.dea...@arm.com> > > > > > > wrote: > > > > > >> > > > > > >> +static inline void of_iommu_set_ops(struct device_node *np, > > > > > >> + const struct iommu_ops *ops) > > > > > >> +{ > > > > > >> + np->data = (struct iommu_ops *)ops; > > > > > >> +} > > > > > >> + > > > > > >> +static inline struct iommu_ops *of_iommu_get_ops(struct > > > > > >> device_node *np) > > > > > >> +{ > > > > > >> + return np->data; > > > > > >> +} > > > > > > > > > > > > This may collide with other users. While use of it is rare, PPC uses > > > > > > it in its PCI code. The OF_DYNAMIC code frees it but never actually > > > > > > sets it. There may be some coming usage with the DT overlay code or > > > > > > that's just a bug. Pantelis or Grant can comment. If not, I think we > > > > > > really should try to get rid of this pointer rather than expand it's > > > > > > usage. > > > > > > > > > > > > I didn't see a user of this. I'm guessing that is coming in a SMMU > > > > > > patch? > > > > > > > > > > Good catch. This is not good. The data pointer should be avoided since > > > > > there are no controls over its use. Until a better solution can be > > > > > implemented, probably the safest thing to do is add a struct iommu_ops > > > > > pointer to struct device_node. However, assuming that only a small > > > > > portion of nodes will actually have iommu_ops set, I'd rather see a > > > > > separate registry that matches device_nodes to iommu_ops. > > > > > > > > Fair enough. Will, can you take a copy of drivers/dma/of-dma.c and > > > > adapt it as needed? It should be exactly what we need to start > > > > out and can be extended and generalized later. > > > > > > Sure, I'll add this to my list of stuff to do for 3.20. > > > > Does that mean the we don't get any of the patches for 3.19 despite the > > Acks? > > Hmm, I don't know how useful they are without the get/set ops and I don't > think I can get those ready for 3.19 given where we currently are. > > Grant's suggestion of adding an iommu_ops pointer to device_node would work > as a temporary hack, but anything more advanced is going to need proper > review.
Right. I guess it doesn't hurt much if we put the new pointer inside #ifdef CONFIG_OF_IOMMU, then at least there is no significant size increase in most DT based platforms. Arnd _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu