From mboxrd@z Thu Jan 1 00:00:00 1970 From: laurent.pinchart@ideasonboard.com (Laurent Pinchart) Date: Wed, 10 Sep 2014 16:01:34 +0300 Subject: [RFC PATCH v2 4/7] iommu: provide helper function to configure an IOMMU for an of master In-Reply-To: <1409680587-29818-5-git-send-email-will.deacon@arm.com> References: <1409680587-29818-1-git-send-email-will.deacon@arm.com> <1409680587-29818-5-git-send-email-will.deacon@arm.com> Message-ID: <1486715.2XVviDPC9Z@avalon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Will, Thank you for the patch. On Tuesday 02 September 2014 18:56:24 Will Deacon wrote: > The generic IOMMU device-tree bindings can be used to add arbitrary OF > masters to an IOMMU with a compliant binding. > > This patch introduces of_iommu_configure, which does exactly that. > > Signed-off-by: Will Deacon > --- > drivers/iommu/Kconfig | 2 +- > drivers/iommu/of_iommu.c | 52 ++++++++++++++++++++++++++++++++++++++++++ > include/linux/dma-mapping.h | 7 ++++++ > include/linux/of_iommu.h | 8 +++++++ > 4 files changed, 68 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > index dd5112265cc9..6d13f962f156 100644 > --- a/drivers/iommu/Kconfig > +++ b/drivers/iommu/Kconfig > @@ -15,7 +15,7 @@ if IOMMU_SUPPORT > > config OF_IOMMU > def_bool y > - depends on OF > + depends on OF && IOMMU_API > > config FSL_PAMU > bool "Freescale IOMMU support" > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c > index f9209666157c..1188c929ffa7 100644 > --- a/drivers/iommu/of_iommu.c > +++ b/drivers/iommu/of_iommu.c > @@ -18,6 +18,7 @@ > */ > > #include > +#include > #include > #include > #include > @@ -90,6 +91,57 @@ int of_get_dma_window(struct device_node *dn, const char > *prefix, int index, } > EXPORT_SYMBOL_GPL(of_get_dma_window); > > +struct iommu_dma_mapping *of_iommu_configure(struct device *dev) > +{ > + struct of_phandle_args iommu_spec; > + struct iommu_dma_mapping *mapping; > + struct bus_type *bus = dev->bus; > + const struct iommu_ops *ops = bus->iommu_ops; > + struct iommu_data *iommu = NULL; > + int idx = 0; > + > + if (!iommu_present(bus) || !ops->of_xlate) > + return NULL; > + > + /* > + * We don't currently walk up the tree looking for a parent IOMMU. > + * See the `Notes:' section of > + * Documentation/devicetree/bindings/iommu/iommu.txt > + */ > + while (!of_parse_phandle_with_args(dev->of_node, "iommus", > + "#iommu-cells", idx, > + &iommu_spec)) { > + struct device_node *np = iommu_spec.np; > + struct iommu_data *data = of_iommu_get_data(np); > + > + if (!iommu) { > + if (!ops->of_xlate(dev, &iommu_spec)) > + iommu = data; If I understand the code correctly, this will call of_xlate for the first IOMMU reference only and silently ignore all subsequent references if they point to the same IOMMU device but with different stream/requester IDs. Is that the desired behaviour ? > + } else if (iommu != data) { > + pr_warn("Rejecting device %s with multiple IOMMU instances\n", > + dev_name(dev)); > + iommu = NULL; > + } > + > + of_node_put(np); > + > + if (!iommu) > + break; > + > + idx++; > + } > + > + if (!iommu) > + return NULL; > + > + mapping = devm_kzalloc(dev, sizeof(*mapping), GFP_KERNEL); > + if (!mapping) > + return NULL; > + > + mapping->iommu = iommu; > + return mapping; > +} > + > void __init of_iommu_init(void) > { > struct device_node *np; > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index 0f7f7b68b0db..16bf92f71c3e 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -62,6 +62,13 @@ struct dma_map_ops { > int is_phys; > }; > > +struct iommu_data; > + > +struct iommu_dma_mapping { > + struct iommu_data *iommu; > + struct list_head node; > +}; > + > #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1)) > > #define DMA_MASK_NONE 0x0ULL > diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h > index a39e2d78f735..f2d3b1e780d7 100644 > --- a/include/linux/of_iommu.h > +++ b/include/linux/of_iommu.h > @@ -1,9 +1,12 @@ > #ifndef __OF_IOMMU_H > #define __OF_IOMMU_H > > +#include > #include > #include > > +struct iommu_dma_mapping; > + > #ifdef CONFIG_OF_IOMMU > > extern int of_get_dma_window(struct device_node *dn, const char *prefix, > @@ -11,6 +14,7 @@ extern int of_get_dma_window(struct device_node *dn, const > char *prefix, size_t *size); > > extern void of_iommu_init(void); > +extern struct iommu_dma_mapping *of_iommu_configure(struct device *dev); > > #else > > @@ -22,6 +26,10 @@ static inline int of_get_dma_window(struct device_node > *dn, const char *prefix, } > > static inline void of_iommu_init(void) { } > +static inline struct iommu_dma_mapping *of_iommu_configure(struct device > *dev) +{ > + return NULL; > +} > > #endif /* CONFIG_OF_IOMMU */ -- Regards, Laurent Pinchart