Messages in this thread Patch in this message | | | From | Mark Brown <> | Subject | [PATCH] irq_domain: Standardise legacy/linear domain selection | Date | Sat, 19 May 2012 13:02:00 +0100 |
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A large proportion of interrupt controllers that support legacy mappings do so because non-DT systems need to use fixed IRQ numbers when registering devices via buses but can otherwise use a linear mapping. The interrupt controller itself typically is not affected by the mapping used and best practice is to use a linear mapping where possible so drivers frequently select at runtime depending on if a legacy range has been allocated to them.
Standardise this behaviour by providing irq_domain_register_simple() which will allocate a linear mapping unless a positive first_irq is provided in which case it will fall back to a legacy mapping. This helps make best practice for irq_domain adoption clearer.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> --- Documentation/IRQ-domain.txt | 5 +++++ include/linux/irqdomain.h | 5 +++++ kernel/irq/irqdomain.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+)
diff --git a/Documentation/IRQ-domain.txt b/Documentation/IRQ-domain.txt index 27dcaab..1401cec 100644 --- a/Documentation/IRQ-domain.txt +++ b/Documentation/IRQ-domain.txt @@ -93,6 +93,7 @@ Linux IRQ number into the hardware. Most drivers cannot use this mapping. ==== Legacy ==== +irq_domain_add_simple() irq_domain_add_legacy() irq_domain_add_legacy_isa() @@ -115,3 +116,7 @@ The legacy map should only be used if fixed IRQ mappings must be supported. For example, ISA controllers would use the legacy map for mapping Linux IRQs 0-15 so that existing ISA drivers get the correct IRQ numbers. + +Most users of legacy mappings should use irq_domain_add_simple() which +will use a legacy domain only if an IRQ range is supplied by the +system and will otherwise use a linear domain mapping. diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h index c65740d..fcf4142 100644 --- a/include/linux/irqdomain.h +++ b/include/linux/irqdomain.h @@ -112,6 +112,11 @@ struct irq_domain { }; #ifdef CONFIG_IRQ_DOMAIN +struct irq_domain *irq_domain_add_simple(struct device_node *of_node, + unsigned int size, + unsigned int first_irq, + const struct irq_domain_ops *ops, + void *host_data); struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, unsigned int size, unsigned int first_irq, diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index d0e50eb..86ae10f 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -77,6 +77,36 @@ static unsigned int irq_domain_legacy_revmap(struct irq_domain *domain, } /** + * irq_domain_add_simple() - Allocate and register a simple irq_domain. + * @of_node: pointer to interrupt controller's device tree node. + * @size: total number of irqs in mapping + * @first_irq: first number of irq block assigned to the domain + * @ops: map/unmap domain callbacks + * @host_data: Controller private data pointer + * + * Allocates a legacy irq_domain if irq_base is positive or a linear + * domain otherwise. + * + * This is intended to implement the expected behaviour for most + * interrupt controllers which is that a linear mapping should + * normally be used unless the system requires a legacy mapping in + * order to support supplying interrupt numbers during non-DT + * registration of devices. + */ +struct irq_domain *irq_domain_add_simple(struct device_node *of_node, + unsigned int size, + unsigned int first_irq, + const struct irq_domain_ops *ops, + void *host_data) +{ + if (first_irq > 0) + return irq_domain_add_legacy(of_node, size, first_irq, 0, + ops, host_data); + else + return irq_domain_add_linear(of_node, size, ops, host_data); +} + +/** * irq_domain_add_legacy() - Allocate and register a legacy revmap irq_domain. * @of_node: pointer to interrupt controller's device tree node. * @size: total number of irqs in legacy mapping -- 1.7.10
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