Messages in this thread | | | Subject | Re: [RFC PATCH 1/8] of/device: Allow specifying a custom iommu_spec to of_dma_configure | From | Robin Murphy <> | Date | Tue, 16 Feb 2021 12:47:43 +0000 |
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Hi Mikko,
On 2021-02-08 16:38, Mikko Perttunen wrote: > To allow for more customized device tree bindings that point to IOMMUs, > allow manual specification of iommu_spec to of_dma_configure. > > The initial use case for this is with Host1x, where the driver manages > a set of device tree-defined IOMMU contexts that are dynamically > allocated to various users. These contexts don't correspond to > platform devices and are instead attached to dummy devices on a custom > software bus.
I'd suggest taking a closer look at the patches that made this of_dma_configure_id() in the first place, and the corresponding bus code in fsl-mc. At this level, Host1x sounds effectively identical to DPAA2 in terms of being a bus of logical devices composed from bits of implicit behind-the-scenes hardware. I mean, compare your series title to the fact that their identifiers are literally named "Isolation Context ID" ;)
Please just use the existing mechanisms to describe a mapping between Host1x context IDs and SMMU Stream IDs, rather than what looks like a giant hacky mess here.
(This also reminds me I wanted to rip out all the PCI special-cases and convert pci_dma_configure() over to passing its own IDs too, so thanks for the memory-jog...)
Robin.
> Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com> > --- > drivers/iommu/of_iommu.c | 12 ++++++++---- > drivers/of/device.c | 9 +++++---- > include/linux/of_device.h | 34 +++++++++++++++++++++++++++------- > include/linux/of_iommu.h | 6 ++++-- > 4 files changed, 44 insertions(+), 17 deletions(-) > > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c > index e505b9130a1c..3fefa6c63863 100644 > --- a/drivers/iommu/of_iommu.c > +++ b/drivers/iommu/of_iommu.c > @@ -87,8 +87,7 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index, > } > EXPORT_SYMBOL_GPL(of_get_dma_window); > > -static int of_iommu_xlate(struct device *dev, > - struct of_phandle_args *iommu_spec) > +int of_iommu_xlate(struct device *dev, struct of_phandle_args *iommu_spec) > { > const struct iommu_ops *ops; > struct fwnode_handle *fwnode = &iommu_spec->np->fwnode; > @@ -117,6 +116,7 @@ static int of_iommu_xlate(struct device *dev, > module_put(ops->owner); > return ret; > } > +EXPORT_SYMBOL_GPL(of_iommu_xlate); > > static int of_iommu_configure_dev_id(struct device_node *master_np, > struct device *dev, > @@ -177,7 +177,8 @@ static int of_iommu_configure_device(struct device_node *master_np, > > const struct iommu_ops *of_iommu_configure(struct device *dev, > struct device_node *master_np, > - const u32 *id) > + const u32 *id, > + struct of_phandle_args *iommu_spec) > { > const struct iommu_ops *ops = NULL; > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > @@ -209,7 +210,10 @@ const struct iommu_ops *of_iommu_configure(struct device *dev, > err = pci_for_each_dma_alias(to_pci_dev(dev), > of_pci_iommu_init, &info); > } else { > - err = of_iommu_configure_device(master_np, dev, id); > + if (iommu_spec) > + err = of_iommu_xlate(dev, iommu_spec); > + else > + err = of_iommu_configure_device(master_np, dev, id); > > fwspec = dev_iommu_fwspec_get(dev); > if (!err && fwspec) > diff --git a/drivers/of/device.c b/drivers/of/device.c > index aedfaaafd3e7..84ada2110c5b 100644 > --- a/drivers/of/device.c > +++ b/drivers/of/device.c > @@ -88,8 +88,9 @@ int of_device_add(struct platform_device *ofdev) > * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events > * to fix up DMA configuration. > */ > -int of_dma_configure_id(struct device *dev, struct device_node *np, > - bool force_dma, const u32 *id) > +int __of_dma_configure(struct device *dev, struct device_node *np, > + bool force_dma, const u32 *id, > + struct of_phandle_args *iommu_spec) > { > const struct iommu_ops *iommu; > const struct bus_dma_region *map = NULL; > @@ -170,7 +171,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np, > dev_dbg(dev, "device is%sdma coherent\n", > coherent ? " " : " not "); > > - iommu = of_iommu_configure(dev, np, id); > + iommu = of_iommu_configure(dev, np, id, iommu_spec); > if (PTR_ERR(iommu) == -EPROBE_DEFER) { > kfree(map); > return -EPROBE_DEFER; > @@ -184,7 +185,7 @@ int of_dma_configure_id(struct device *dev, struct device_node *np, > dev->dma_range_map = map; > return 0; > } > -EXPORT_SYMBOL_GPL(of_dma_configure_id); > +EXPORT_SYMBOL_GPL(__of_dma_configure); > > int of_device_register(struct platform_device *pdev) > { > diff --git a/include/linux/of_device.h b/include/linux/of_device.h > index 07ca187fc5e4..40cc3e788cb9 100644 > --- a/include/linux/of_device.h > +++ b/include/linux/of_device.h > @@ -55,14 +55,27 @@ static inline struct device_node *of_cpu_device_node_get(int cpu) > return of_node_get(cpu_dev->of_node); > } > > -int of_dma_configure_id(struct device *dev, > +int __of_dma_configure(struct device *dev, > struct device_node *np, > - bool force_dma, const u32 *id); > + bool force_dma, const u32 *id, > + struct of_phandle_args *iommu_spec); > static inline int of_dma_configure(struct device *dev, > struct device_node *np, > bool force_dma) > { > - return of_dma_configure_id(dev, np, force_dma, NULL); > + return __of_dma_configure(dev, np, force_dma, NULL, NULL); > +} > +static inline int of_dma_configure_id(struct device *dev, > + struct device_node *np, > + bool force_dma, const u32 *id) > +{ > + return __of_dma_configure(dev, np, force_dma, id, NULL); > +} > +static inline int > +of_dma_configure_iommu_spec(struct device *dev, struct device_node *np, > + bool force_dma, struct of_phandle_args *iommu_spec) > +{ > + return __of_dma_configure(dev, np, force_dma, NULL, iommu_spec); > } > #else /* CONFIG_OF */ > > @@ -112,18 +125,25 @@ static inline struct device_node *of_cpu_device_node_get(int cpu) > return NULL; > } > > -static inline int of_dma_configure_id(struct device *dev, > +static inline int of_dma_configure(struct device *dev, > struct device_node *np, > bool force_dma) > { > return 0; > } > -static inline int of_dma_configure(struct device *dev, > - struct device_node *np, > - bool force_dma) > + > +static inline int of_dma_configure_id(struct device *dev, > + struct device_node *np, > + bool force_dma, const u32 *id) > { > return 0; > } > + > +static inline int > +of_dma_configure_iommu_spec(struct device *dev, struct device_node *np, > + bool force_dma, struct of_phandle_args *iommu_spec) > +{ return 0; > +} > #endif /* CONFIG_OF */ > > #endif /* _LINUX_OF_DEVICE_H */ > diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h > index 16f4b3e87f20..e8d1e6d32d77 100644 > --- a/include/linux/of_iommu.h > +++ b/include/linux/of_iommu.h > @@ -14,7 +14,8 @@ extern int of_get_dma_window(struct device_node *dn, const char *prefix, > > extern const struct iommu_ops *of_iommu_configure(struct device *dev, > struct device_node *master_np, > - const u32 *id); > + const u32 *id, > + struct of_phandle_args *iommu_spec); > > #else > > @@ -27,7 +28,8 @@ static inline int of_get_dma_window(struct device_node *dn, const char *prefix, > > static inline const struct iommu_ops *of_iommu_configure(struct device *dev, > struct device_node *master_np, > - const u32 *id) > + const u32 *id, > + struct of_phandle_args *iommu_spec); > { > return NULL; > } >
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