From 7b6ef1262549f6afc5c881aaef80beb8fd15f908 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 7 May 2014 15:44:05 +0000 Subject: [PATCH] genirq: Provide generic hwirq allocation facility Not really the solution to the problem, but at least it confines the mess in the core code and allows to get rid of the create/destroy_irq variants from hell, i.e. 3 implementations with different semantics plus the x86 specific variants __create_irqs and create_irq_nr which have been invented in another circle of hell. x86 : x86 should be converted to irq domains and I'm deliberately making it impossible to do the multi-vector MSI support by adding more crap to the current mess. It's not that hard to do and I'm really tired of the trainwrecks which have been invented by baindaid engineering so far. Any attempt to do multi-vector MSI or ioapic hotplug without converting to irq domains is NAKed hereby. tile: Might use irq domains as well, but it has a very limited interrupt space, so handling it via this functionality might be the right thing to do even in the long run. ia64: That's an hopeless case, as I doubt that anyone has the stomach to rewrite the homebrewn dynamic allocation facilities. I stared at it for a couple of hours and gave up. The create/destroy_irq mess could be made private to itanic right away if there wouldn't be the iommu/dmar driver being shared with x86. So to do that I'm going to add a separate ia64 specific implementation later in order not to deep-six itanic right away. Signed-off-by: Thomas Gleixner Reviewed-by: Grant Likely Cc: Tony Luck Cc: Peter Zijlstra Cc: Chris Metcalf Cc: Fenghua Yu Cc: x86@kernel.org Link: http://lkml.kernel.org/r/20140507154334.208629358@linutronix.de Signed-off-by: Thomas Gleixner --- include/linux/irq.h | 15 +++++++++++++ kernel/irq/Kconfig | 5 +++++ kernel/irq/irqdesc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 71 insertions(+) diff --git a/include/linux/irq.h b/include/linux/irq.h index 5c57efb863d0..c75dd161d37f 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -637,6 +637,21 @@ static inline int irq_reserve_irq(unsigned int irq) return irq_reserve_irqs(irq, 1); } +#ifdef CONFIG_GENERIC_IRQ_LEGACY_ALLOC_HWIRQ +unsigned int irq_alloc_hwirqs(int cnt, int node); +static inline unsigned int irq_alloc_hwirq(int node) +{ + return irq_alloc_hwirqs(1, node); +} +void irq_free_hwirqs(unsigned int from, int cnt); +static inline void irq_free_hwirq(unsigned int irq) +{ + return irq_free_hwirqs(irq, 1); +} +int arch_setup_hwirq(unsigned int irq, int node); +void arch_teardown_hwirq(unsigned int irq); +#endif + #ifndef irq_reg_writel # define irq_reg_writel(val, addr) writel(val, addr) #endif diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index 07cbdfea9ae2..a83f10e406c1 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -17,6 +17,11 @@ config GENERIC_IRQ_SHOW config GENERIC_IRQ_SHOW_LEVEL bool +# Facility to allocate a hardware interrupt. This is legacy support +# and should not be used in new code. Use irq domains instead. +config GENERIC_IRQ_LEGACY_ALLOC_HWIRQ + bool + # Support for delayed migration from interrupt context config GENERIC_PENDING_IRQ bool diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index bb07f2928f4b..f388ade5e792 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -396,6 +396,57 @@ err: } EXPORT_SYMBOL_GPL(__irq_alloc_descs); +#ifdef CONFIG_GENERIC_IRQ_LEGACY_ALLOC_HWIRQ +/** + * irq_alloc_hwirqs - Allocate an irq descriptor and initialize the hardware + * @cnt: number of interrupts to allocate + * @node: node on which to allocate + * + * Returns an interrupt number > 0 or 0, if the allocation fails. + */ +unsigned int irq_alloc_hwirqs(int cnt, int node) +{ + int i, irq = __irq_alloc_descs(-1, 0, cnt, node, NULL); + + if (irq < 0) + return 0; + + for (i = irq; cnt > 0; i++, cnt--) { + if (arch_setup_hwirq(i, node)) + goto err; + irq_clear_status_flags(i, _IRQ_NOREQUEST); + } + return irq; + +err: + for (i--; i >= irq; i--) { + irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE); + arch_teardown_hwirq(i); + } + irq_free_descs(irq, cnt); + return 0; +} +EXPORT_SYMBOL_GPL(irq_alloc_hwirqs); + +/** + * irq_free_hwirqs - Free irq descriptor and cleanup the hardware + * @from: Free from irq number + * @cnt: number of interrupts to free + * + */ +void irq_free_hwirqs(unsigned int from, int cnt) +{ + int i; + + for (i = from; cnt > 0; i++, cnt--) { + irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE); + arch_teardown_hwirq(i); + } + irq_free_descs(from, cnt); +} +EXPORT_SYMBOL_GPL(irq_free_hwirqs); +#endif + /** * irq_reserve_irqs - mark irqs allocated * @from: mark from irq number -- 2.20.1