[PATCH v3 1/2] irq: add irq_domain translation infrastructure
Grant Likely
grant.likely at secretlab.ca
Tue Jul 26 05:40:01 EDT 2011
On Tue, Jul 26, 2011 at 3:36 AM, Grant Likely <grant.likely at secretlab.ca> wrote:
> This patch adds irq_domain infrastructure for translating from
> hardware irq numbers to linux irqs. This is particularly important
> for architectures adding device tree support because the current
> implementation (excluding PowerPC and SPARC) cannot handle
> translation for more than a single interrupt controller. irq_domain
> supports device tree translation for any number of interrupt
> controllers.
>
> This patch converts x86, Microblaze, ARM and MIPS to use irq_domain
> for device tree irq translation. x86 is untested beyond compiling it,
> irq_domain is enabled for MIPS and Microblaze, but the old behaviour is
> preserved until the core code is modified to actually register an
> irq_domain yet. On ARM it works and is required for much of the new
> ARM device tree board support.
Oops, I obviously forgot to update the commit text. This patch only
affects ARM, I've split the MIPS, Microblaze and x86 bits out into a
separate patch. I'll craft new commit text before reposting.
g.
>
> PowerPC has /not/ been converted to use this new infrastructure. It
> is still missing some features before it can replace the virq
> infrastructure already in powerpc (see documentation on
> irq_domain_map/unmap for details). Followup patches will add the
> missing pieces and migrate PowerPC to use irq_domain.
>
> SPARC has its own method of managing interrupts from the device tree
> and is unaffected by this change.
>
> Acked-by: Ralf Baechle <ralf at linux-mips.org>
> Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
> ---
> arch/arm/Kconfig | 1
> arch/arm/include/asm/prom.h | 5 --
> arch/arm/kernel/devtree.c | 14 -----
> include/linux/irq.h | 6 ++
> include/linux/irqdomain.h | 81 ++++++++++++++++++++++++++++
> include/linux/of_irq.h | 4 +
> kernel/irq/Kconfig | 4 +
> kernel/irq/Makefile | 1
> kernel/irq/irqdomain.c | 123 +++++++++++++++++++++++++++++++++++++++++++
> 9 files changed, 220 insertions(+), 19 deletions(-)
> create mode 100644 include/linux/irqdomain.h
> create mode 100644 kernel/irq/irqdomain.c
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 9cb1f4b..b2695aa 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1680,6 +1680,7 @@ config USE_OF
> bool "Flattened Device Tree support"
> select OF
> select OF_EARLY_FLATTREE
> + select IRQ_DOMAIN
> help
> Include support for flattened device tree machine descriptions.
>
> diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h
> index 11b8708..6f65ca8 100644
> --- a/arch/arm/include/asm/prom.h
> +++ b/arch/arm/include/asm/prom.h
> @@ -16,11 +16,6 @@
> #include <asm/setup.h>
> #include <asm/irq.h>
>
> -static inline void irq_dispose_mapping(unsigned int virq)
> -{
> - return;
> -}
> -
> extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys);
> extern void arm_dt_memblock_reserve(void);
>
> diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
> index 0cdd7b4..1a33e9d 100644
> --- a/arch/arm/kernel/devtree.c
> +++ b/arch/arm/kernel/devtree.c
> @@ -132,17 +132,3 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
>
> return mdesc_best;
> }
> -
> -/**
> - * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq#
> - *
> - * Currently the mapping mechanism is trivial; simple flat hwirq numbers are
> - * mapped 1:1 onto Linux irq numbers. Cascaded irq controllers are not
> - * supported.
> - */
> -unsigned int irq_create_of_mapping(struct device_node *controller,
> - const u32 *intspec, unsigned int intsize)
> -{
> - return intspec[0];
> -}
> -EXPORT_SYMBOL_GPL(irq_create_of_mapping);
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index 5f69504..87a06f3 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -108,14 +108,18 @@ enum {
> };
>
> struct msi_desc;
> +struct irq_domain;
>
> /**
> * struct irq_data - per irq and irq chip data passed down to chip functions
> * @irq: interrupt number
> + * @hwirq: hardware interrupt number, local to the interrupt domain
> * @node: node index useful for balancing
> * @state_use_accessors: status information for irq chip functions.
> * Use accessor functions to deal with it
> * @chip: low level interrupt hardware access
> + * @domain: Interrupt translation domain; responsible for mapping
> + * between hwirq number and linux irq number.
> * @handler_data: per-IRQ data for the irq_chip methods
> * @chip_data: platform-specific per-chip private data for the chip
> * methods, to allow shared chip implementations
> @@ -128,9 +132,11 @@ struct msi_desc;
> */
> struct irq_data {
> unsigned int irq;
> + unsigned long hwirq;
> unsigned int node;
> unsigned int state_use_accessors;
> struct irq_chip *chip;
> + struct irq_domain *domain;
> void *handler_data;
> void *chip_data;
> struct msi_desc *msi_desc;
> diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
> new file mode 100644
> index 0000000..8f2c10a
> --- /dev/null
> +++ b/include/linux/irqdomain.h
> @@ -0,0 +1,81 @@
> +/*
> + * irq_domain - IRQ translation domains
> + *
> + * Translation infrastructure between hw and linux irq numbers. This is
> + * helpful for interrupt controllers to implement mapping between hardware
> + * irq numbers and the Linux irq number space.
> + *
> + * irq_domains also have a hook for translating device tree interrupt
> + * representation into a hardware irq number that can be mapped back to a
> + * Linux irq number without any extra platform support code.
> + *
> + * irq_domain is expected to be embedded in an interrupt controller's private
> + * data structure.
> + */
> +#ifndef _LINUX_IRQDOMAIN_H
> +#define _LINUX_IRQDOMAIN_H
> +
> +#include <linux/irq.h>
> +
> +#ifdef CONFIG_IRQ_DOMAIN
> +struct device_node;
> +struct irq_domain;
> +
> +/**
> + * struct irq_domain_ops - Methods for irq_domain objects
> + * @to_irq: (optional) given a local hardware irq number, return the linux
> + * irq number. If to_irq is not implemented, then the irq_domain
> + * will use this translation: irq = (domain->irq_base + hwirq)
> + * @dt_translate: Given a device tree node and interrupt specifier, decode
> + * the hardware irq number and linux irq type value.
> + */
> +struct irq_domain_ops {
> + unsigned int (*to_irq)(struct irq_domain *d, unsigned long hwirq);
> +
> +#ifdef CONFIG_OF
> + int (*dt_translate)(struct irq_domain *d, struct device_node *node,
> + const u32 *intspec, unsigned int intsize,
> + unsigned long *out_hwirq, unsigned int *out_type);
> +#endif /* CONFIG_OF */
> +};
> +
> +/**
> + * struct irq_domain - Hardware interrupt number translation object
> + * @list: Element in global irq_domain list.
> + * @irq_base: Start of irq_desc range assigned to the irq_domain. The creator
> + * of the irq_domain is responsible for allocating the array of
> + * irq_desc structures.
> + * @nr_irq: Number of irqs managed by the irq domain
> + * @ops: pointer to irq_domain methods
> + * @priv: private data pointer for use by owner. Not touched by irq_domain
> + * core code.
> + * @of_node: (optional) Pointer to device tree nodes associated with the
> + * irq_domain. Used when decoding device tree interrupt specifiers.
> + */
> +struct irq_domain {
> + struct list_head list;
> + unsigned int irq_base;
> + unsigned int nr_irq;
> + const struct irq_domain_ops *ops;
> + void *priv;
> + struct device_node *of_node;
> +};
> +
> +/**
> + * irq_domain_to_irq() - Translate from a hardware irq to a linux irq number
> + *
> + * Returns the linux irq number associated with a hardware irq. By default,
> + * the mapping is irq == domain->irq_base + hwirq, but this mapping can
> + * be overridden if the irq_domain implements a .to_irq() hook.
> + */
> +static inline unsigned int irq_domain_to_irq(struct irq_domain *d,
> + unsigned long hwirq)
> +{
> + return d->ops->to_irq ? d->ops->to_irq(d, hwirq) : d->irq_base + hwirq;
> +}
> +
> +extern void irq_domain_add(struct irq_domain *domain);
> +extern void irq_domain_del(struct irq_domain *domain);
> +#endif /* CONFIG_IRQ_DOMAIN */
> +
> +#endif /* _LINUX_IRQDOMAIN_H */
> diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
> index e6955f5..cd2e61c 100644
> --- a/include/linux/of_irq.h
> +++ b/include/linux/of_irq.h
> @@ -63,6 +63,9 @@ extern int of_irq_map_one(struct device_node *device, int index,
> extern unsigned int irq_create_of_mapping(struct device_node *controller,
> const u32 *intspec,
> unsigned int intsize);
> +#ifdef CONFIG_IRQ_DOMAIN
> +extern void irq_dispose_mapping(unsigned int irq);
> +#endif
> extern int of_irq_to_resource(struct device_node *dev, int index,
> struct resource *r);
> extern int of_irq_count(struct device_node *dev);
> @@ -70,6 +73,7 @@ extern int of_irq_to_resource_table(struct device_node *dev,
> struct resource *res, int nr_irqs);
> extern struct device_node *of_irq_find_parent(struct device_node *child);
>
> +
> #endif /* CONFIG_OF_IRQ */
> #endif /* CONFIG_OF */
> #endif /* __OF_IRQ_H */
> diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
> index d1d051b3..5a38bf4 100644
> --- a/kernel/irq/Kconfig
> +++ b/kernel/irq/Kconfig
> @@ -52,6 +52,10 @@ config IRQ_EDGE_EOI_HANDLER
> config GENERIC_IRQ_CHIP
> bool
>
> +# Generic irq_domain hw <--> linux irq number translation
> +config IRQ_DOMAIN
> + bool
> +
> # Support forced irq threading
> config IRQ_FORCED_THREADING
> bool
> diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
> index 7329005..fff1738 100644
> --- a/kernel/irq/Makefile
> +++ b/kernel/irq/Makefile
> @@ -2,6 +2,7 @@
> obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o
> obj-$(CONFIG_GENERIC_IRQ_CHIP) += generic-chip.o
> obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
> +obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o
> obj-$(CONFIG_PROC_FS) += proc.o
> obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
> obj-$(CONFIG_PM_SLEEP) += pm.o
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> new file mode 100644
> index 0000000..171b754
> --- /dev/null
> +++ b/kernel/irq/irqdomain.c
> @@ -0,0 +1,123 @@
> +
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +
> +static LIST_HEAD(irq_domain_list);
> +static DEFINE_MUTEX(irq_domain_mutex);
> +
> +/**
> + * irq_domain_add() - Register an irq_domain
> + * @domain: ptr to initialized irq_domain structure
> + *
> + * Registers an irq_domain structure. The irq_domain must at a minimum be
> + * initialized with an ops structure pointer, and either a ->to_irq hook or
> + * a valid irq_base value. Everything else is optional.
> + */
> +void irq_domain_add(struct irq_domain *domain)
> +{
> + struct irq_data *d;
> + int hwirq;
> +
> + /*
> + * This assumes that the irq_domain owner has already allocated
> + * the irq_descs. This block will be removed when support for dynamic
> + * allocation of irq_descs is added to irq_domain.
> + */
> + for (hwirq = 0; hwirq < domain->nr_irq; hwirq++) {
> + d = irq_get_irq_data(irq_domain_to_irq(domain, hwirq));
> + if (d || d->domain) {
> + /* things are broken; just report, don't clean up */
> + WARN(1, "error: irq_desc already assigned to a domain");
> + return;
> + }
> + d->domain = domain;
> + d->hwirq = hwirq;
> + }
> +
> + mutex_lock(&irq_domain_mutex);
> + list_add(&domain->list, &irq_domain_list);
> + mutex_unlock(&irq_domain_mutex);
> +}
> +
> +/**
> + * irq_domain_del() - Unregister an irq_domain
> + * @domain: ptr to registered irq_domain.
> + */
> +void irq_domain_del(struct irq_domain *domain)
> +{
> + struct irq_data *d;
> + int hwirq;
> +
> + mutex_lock(&irq_domain_mutex);
> + list_del(&domain->list);
> + mutex_unlock(&irq_domain_mutex);
> +
> + /* Clear the irq_domain assignments */
> + for (hwirq = 0; hwirq < domain->nr_irq; hwirq++) {
> + d = irq_get_irq_data(irq_domain_to_irq(domain, hwirq));
> + d->domain = NULL;
> + }
> +}
> +
> +#if defined(CONFIG_OF_IRQ)
> +/**
> + * irq_create_of_mapping() - Map a linux irq number from a DT interrupt spec
> + *
> + * Used by the device tree interrupt mapping code to translate a device tree
> + * interrupt specifier to a valid linux irq number. Returns either a valid
> + * linux IRQ number or 0.
> + *
> + * When the caller no longer need the irq number returned by this function it
> + * should arrange to call irq_dispose_mapping().
> + */
> +unsigned int irq_create_of_mapping(struct device_node *controller,
> + const u32 *intspec, unsigned int intsize)
> +{
> + struct irq_domain *domain;
> + unsigned long hwirq;
> + unsigned int irq, type;
> + int rc = -EINVAL;
> +
> + /* Find a domain which can translate the irq spec */
> + mutex_lock(&irq_domain_mutex);
> + list_for_each_entry(domain, &irq_domain_list, list) {
> + if (!domain->ops->dt_translate)
> + continue;
> + rc = domain->ops->dt_translate(domain, controller,
> + intspec, intsize, &hwirq, &type);
> + if (rc == 0)
> + break;
> + }
> + mutex_unlock(&irq_domain_mutex);
> +
> + if (rc != 0)
> + return 0;
> +
> + irq = irq_domain_to_irq(domain, hwirq);
> + if (type != IRQ_TYPE_NONE)
> + irq_set_irq_type(irq, type);
> + pr_debug("%s: mapped hwirq=%i to irq=%i, flags=%x\n",
> + controller->full_name, (int)hwirq, irq, type);
> + return irq;
> +}
> +EXPORT_SYMBOL_GPL(irq_create_of_mapping);
> +
> +/**
> + * irq_dispose_mapping() - Discard a mapping created by irq_create_of_mapping()
> + * @irq: linux irq number to be discarded
> + *
> + * Calling this function indicates the caller no longer needs a reference to
> + * the linux irq number returned by a prior call to irq_create_of_mapping().
> + */
> +void irq_dispose_mapping(unsigned int irq)
> +{
> + /*
> + * nothing yet; will be filled when support for dynamic allocation of
> + * irq_descs is added to irq_domain
> + */
> +}
> +EXPORT_SYMBOL_GPL(irq_dispose_mapping);
> +#endif /* CONFIG_OF_IRQ */
>
>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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