cf68d7a3f7
When registering irq chip drivers, one common requirement is to specify the irq_domain irq_base and nr_irq. These fields represent the system wide logical interrupt range the domain occupies. For systems with only one interrupt controller, it's trivial to know these values. But for systems with several irq chip drivers, it becomes painful to keep track of interrupt ranges in platform defines. These create needless compile time dependencies, of which the Device Tree aims to solve. irq_alloc_desc() can search for a free irq, but is very inefficient for determining the availability of large ranges. Additionally, some irq chip drivers allocate irq descriptors lazily. For example, portions of the Device Tree may not be parsed until a particular bus is probed. But of_irq_init() is intended to be run at init time, and this is a natural time to allocate irq domains. Thus by the time we allocate our irq descriptors, we already need to know a range of acceptable irqs to use for the domain. To solve these problems, let's introduce irq_domain_find_free_range(), which will return to the caller the first available irq domain range not used already by the system. This range can then be specified with irq_domain_add(). Change-Id: I8b0f5d25b173c76b8fc5d4f46b3fe9c6bf5c3c8f Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
113 lines
4.2 KiB
C
113 lines
4.2 KiB
C
/*
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* irq_domain - IRQ translation domains
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*
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* Translation infrastructure between hw and linux irq numbers. This is
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* helpful for interrupt controllers to implement mapping between hardware
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* irq numbers and the Linux irq number space.
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*
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* irq_domains also have a hook for translating device tree interrupt
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* representation into a hardware irq number that can be mapped back to a
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* Linux irq number without any extra platform support code.
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*
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* irq_domain is expected to be embedded in an interrupt controller's private
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* data structure.
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*/
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#ifndef _LINUX_IRQDOMAIN_H
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#define _LINUX_IRQDOMAIN_H
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#include <linux/irq.h>
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#include <linux/mod_devicetable.h>
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#ifdef CONFIG_IRQ_DOMAIN
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struct device_node;
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struct irq_domain;
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/**
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* struct irq_domain_ops - Methods for irq_domain objects
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* @to_irq: (optional) given a local hardware irq number, return the linux
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* irq number. If to_irq is not implemented, then the irq_domain
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* will use this translation: irq = (domain->irq_base + hwirq)
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* @dt_translate: Given a device tree node and interrupt specifier, decode
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* the hardware irq number and linux irq type value.
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*/
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struct irq_domain_ops {
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unsigned int (*to_irq)(struct irq_domain *d, unsigned long hwirq);
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#ifdef CONFIG_OF
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int (*dt_translate)(struct irq_domain *d, struct device_node *node,
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const u32 *intspec, unsigned int intsize,
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unsigned long *out_hwirq, unsigned int *out_type);
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#endif /* CONFIG_OF */
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};
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/**
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* struct irq_domain - Hardware interrupt number translation object
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* @list: Element in global irq_domain list.
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* @irq_base: Start of irq_desc range assigned to the irq_domain. The creator
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* of the irq_domain is responsible for allocating the array of
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* irq_desc structures.
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* @nr_irq: Number of irqs managed by the irq domain
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* @hwirq_base: Starting number for hwirqs managed by the irq domain
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* @ops: pointer to irq_domain methods
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* @priv: private data pointer for use by owner. Not touched by irq_domain
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* core code.
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* @of_node: (optional) Pointer to device tree nodes associated with the
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* irq_domain. Used when decoding device tree interrupt specifiers.
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*/
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struct irq_domain {
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struct list_head list;
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unsigned int irq_base;
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unsigned int nr_irq;
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unsigned int hwirq_base;
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const struct irq_domain_ops *ops;
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void *priv;
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struct device_node *of_node;
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};
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/**
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* irq_domain_to_irq() - Translate from a hardware irq to a linux irq number
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*
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* Returns the linux irq number associated with a hardware irq. By default,
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* the mapping is irq == domain->irq_base + hwirq, but this mapping can
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* be overridden if the irq_domain implements a .to_irq() hook.
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*/
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static inline unsigned int irq_domain_to_irq(struct irq_domain *d,
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unsigned long hwirq)
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{
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if (d->ops->to_irq)
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return d->ops->to_irq(d, hwirq);
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if (WARN_ON(hwirq < d->hwirq_base))
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return 0;
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return d->irq_base + hwirq - d->hwirq_base;
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}
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#define irq_domain_for_each_hwirq(d, hw) \
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for (hw = d->hwirq_base; hw < d->hwirq_base + d->nr_irq; hw++)
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#define irq_domain_for_each_irq(d, hw, irq) \
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for (hw = d->hwirq_base, irq = irq_domain_to_irq(d, hw); \
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hw < d->hwirq_base + d->nr_irq; \
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hw++, irq = irq_domain_to_irq(d, hw))
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extern int irq_domain_add(struct irq_domain *domain);
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extern void irq_domain_del(struct irq_domain *domain);
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extern void irq_domain_register(struct irq_domain *domain);
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extern void irq_domain_register_irq(struct irq_domain *domain, int hwirq);
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extern void irq_domain_unregister(struct irq_domain *domain);
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extern void irq_domain_unregister_irq(struct irq_domain *domain, int hwirq);
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extern int irq_domain_find_free_range(unsigned int from, unsigned int cnt);
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#endif /* CONFIG_IRQ_DOMAIN */
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#if defined(CONFIG_IRQ_DOMAIN) && defined(CONFIG_OF_IRQ)
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extern struct irq_domain_ops irq_domain_simple_ops;
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extern void irq_domain_add_simple(struct device_node *controller, int irq_base);
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extern void irq_domain_generate_simple(const struct of_device_id *match,
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u64 phys_base, unsigned int irq_start);
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#else /* CONFIG_IRQ_DOMAIN && CONFIG_OF_IRQ */
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static inline void irq_domain_generate_simple(const struct of_device_id *match,
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u64 phys_base, unsigned int irq_start) { }
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#endif /* CONFIG_IRQ_DOMAIN && CONFIG_OF_IRQ */
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#endif /* _LINUX_IRQDOMAIN_H */
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