On Mon, Dec 1, 2014 at 11:54 PM, Rob Herring <robherri...@gmail.com> wrote: > Adding Grant and Pantelis... > > On Mon, Dec 1, 2014 at 10:57 AM, Will Deacon <will.dea...@arm.com> wrote: >> IOMMU drivers must be initialised before any of their upstream devices, >> otherwise the relevant iommu_ops won't be configured for the bus in >> question. To solve this, a number of IOMMU drivers use initcalls to >> initialise the driver before anything has a chance to be probed. >> >> Whilst this solves the immediate problem, it leaves the job of probing >> the IOMMU completely separate from the iommu_ops to configure the IOMMU, >> which are called on a per-bus basis and require the driver to figure out >> exactly which instance of the IOMMU is being requested. In particular, >> the add_device callback simply passes a struct device to the driver, >> which then has to parse firmware tables or probe buses to identify the >> relevant IOMMU instance. >> >> This patch takes the first step in addressing this problem by adding an >> early initialisation pass for IOMMU drivers, giving them the ability to >> store some per-instance data in their iommu_ops structure and store that >> in their of_node. This can later be used when parsing OF masters to >> identify the IOMMU instance in question. >> >> Acked-by: Arnd Bergmann <a...@arndb.de> >> Acked-by: Joerg Roedel <jroe...@suse.de> >> Acked-by: Marek Szyprowski <m.szyprow...@samsung.com> >> Tested-by: Robin Murphy <robin.mur...@arm.com> >> Signed-off-by: Will Deacon <will.dea...@arm.com> >> --- >> drivers/iommu/of_iommu.c | 17 +++++++++++++++++ >> include/asm-generic/vmlinux.lds.h | 2 ++ >> include/linux/iommu.h | 2 ++ >> include/linux/of_iommu.h | 25 +++++++++++++++++++++++++ >> 4 files changed, 46 insertions(+) >> >> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c >> index e550ccb7634e..89b903406968 100644 >> --- a/drivers/iommu/of_iommu.c >> +++ b/drivers/iommu/of_iommu.c >> @@ -22,6 +22,9 @@ >> #include <linux/of.h> >> #include <linux/of_iommu.h> >> >> +static const struct of_device_id __iommu_of_table_sentinel >> + __used __section(__iommu_of_table_end); >> + >> /** >> * of_get_dma_window - Parse *dma-window property and returns 0 if found. >> * >> @@ -89,3 +92,17 @@ int of_get_dma_window(struct device_node *dn, const char >> *prefix, int index, >> return 0; >> } >> EXPORT_SYMBOL_GPL(of_get_dma_window); >> + >> +void __init of_iommu_init(void) >> +{ >> + struct device_node *np; >> + const struct of_device_id *match, *matches = &__iommu_of_table; >> + >> + for_each_matching_node_and_match(np, matches, &match) { >> + const of_iommu_init_fn init_fn = match->data; >> + >> + if (init_fn(np)) >> + pr_err("Failed to initialise IOMMU %s\n", >> + of_node_full_name(np)); >> + } >> +} >> diff --git a/include/asm-generic/vmlinux.lds.h >> b/include/asm-generic/vmlinux.lds.h >> index aa70cbda327c..bee5d683074d 100644 >> --- a/include/asm-generic/vmlinux.lds.h >> +++ b/include/asm-generic/vmlinux.lds.h >> @@ -164,6 +164,7 @@ >> #define CLKSRC_OF_TABLES() OF_TABLE(CONFIG_CLKSRC_OF, clksrc) >> #define IRQCHIP_OF_MATCH_TABLE() OF_TABLE(CONFIG_IRQCHIP, irqchip) >> #define CLK_OF_TABLES() OF_TABLE(CONFIG_COMMON_CLK, clk) >> +#define IOMMU_OF_TABLES() OF_TABLE(CONFIG_OF_IOMMU, iommu) >> #define RESERVEDMEM_OF_TABLES() OF_TABLE(CONFIG_OF_RESERVED_MEM, >> reservedmem) >> #define CPU_METHOD_OF_TABLES() OF_TABLE(CONFIG_SMP, cpu_method) >> #define EARLYCON_OF_TABLES() OF_TABLE(CONFIG_SERIAL_EARLYCON, earlycon) >> @@ -497,6 +498,7 @@ >> CLK_OF_TABLES() \ >> RESERVEDMEM_OF_TABLES() \ >> CLKSRC_OF_TABLES() \ >> + IOMMU_OF_TABLES() \ >> CPU_METHOD_OF_TABLES() \ >> KERNEL_DTB() \ >> IRQCHIP_OF_MATCH_TABLE() \ >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index e6a7c9ff72f2..7b83f9f8e11d 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -103,6 +103,7 @@ enum iommu_attr { >> * @domain_get_attr: Query domain attributes >> * @domain_set_attr: Change domain attributes >> * @pgsize_bitmap: bitmap of supported page sizes >> + * @priv: per-instance data private to the iommu driver >> */ >> struct iommu_ops { >> bool (*capable)(enum iommu_cap); >> @@ -133,6 +134,7 @@ struct iommu_ops { >> u32 (*domain_get_windows)(struct iommu_domain *domain); >> >> unsigned long pgsize_bitmap; >> + void *priv; >> }; >> >> #define IOMMU_GROUP_NOTIFY_ADD_DEVICE 1 /* Device added */ >> diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h >> index 51a560f34bca..5762cdc8effe 100644 >> --- a/include/linux/of_iommu.h >> +++ b/include/linux/of_iommu.h >> @@ -1,12 +1,17 @@ >> #ifndef __OF_IOMMU_H >> #define __OF_IOMMU_H >> >> +#include <linux/iommu.h> >> +#include <linux/of.h> >> + >> #ifdef CONFIG_OF_IOMMU >> >> extern int of_get_dma_window(struct device_node *dn, const char *prefix, >> int index, unsigned long *busno, dma_addr_t >> *addr, >> size_t *size); >> >> +extern void of_iommu_init(void); >> + >> #else >> >> static inline int of_get_dma_window(struct device_node *dn, const char >> *prefix, >> @@ -16,6 +21,26 @@ static inline int of_get_dma_window(struct device_node >> *dn, const char *prefix, >> return -EINVAL; >> } >> >> +static inline void of_iommu_init(void) { } >> + >> #endif /* CONFIG_OF_IOMMU */ >> >> +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. g. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu