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authorEric W. Biederman <ebiederm@xmission.com>2006-10-04 02:16:37 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-04 07:55:27 -0700
commit3a16d713626735f3016da0521b7bf251cd78e836 (patch)
tree39147d40b681391a578b19fceb50dfe5a7a4a1ab /kernel
parent92db6d10bc1bc43330a4c540fa5b64c83d9d865f (diff)
downloadlinux-3a16d713626735f3016da0521b7bf251cd78e836.tar.bz2
[PATCH] genirq: irq: add a dynamic irq creation API
With the msi support comes a new concept in irq handling, irqs that are created dynamically at run time. Currently the msi code allocates irqs backwards. First it allocates a platform dependent routing value for an interrupt the ``vector'' and then it figures out from the vector which irq you are on. This msi backwards allocator suffers from two basic problems. The allocator suffers because it is trying to do something that is architecture specific in a generic way making it brittle, inflexible, and tied to tightly to the architecture implementation. The alloctor also suffers from it's very backwards nature as it has tied things together that should have no dependencies. To solve the basic dynamic irq allocation problem two new architecture specific functions are added: create_irq and destroy_irq. create_irq takes no input and returns an unused irq number, that won't be reused until it is returned to the free poll with destroy_irq. The irq then can be used for any purpose although the only initial consumer is the msi code. destroy_irq takes an irq number allocated with create_irq and returns it to the free pool. Making this functionality per architecture increases the simplicity of the irq allocation code and increases it's flexibility. dynamic_irq_init() and dynamic_irq_cleanup() are added to automate the irq_desc initializtion that should happen for dynamic irqs. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/chip.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 736cb0bd498f..0dc24386dd99 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -18,6 +18,62 @@
#include "internals.h"
/**
+ * dynamic_irq_init - initialize a dynamically allocated irq
+ * @irq: irq number to initialize
+ */
+void dynamic_irq_init(unsigned int irq)
+{
+ struct irq_desc *desc;
+ unsigned long flags;
+
+ if (irq >= NR_IRQS) {
+ printk(KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
+ WARN_ON(1);
+ return;
+ }
+
+ /* Ensure we don't have left over values from a previous use of this irq */
+ desc = irq_desc + irq;
+ spin_lock_irqsave(&desc->lock, flags);
+ desc->status = IRQ_DISABLED;
+ desc->chip = &no_irq_chip;
+ desc->handle_irq = handle_bad_irq;
+ desc->depth = 1;
+ desc->handler_data = NULL;
+ desc->chip_data = NULL;
+ desc->action = NULL;
+ desc->irq_count = 0;
+ desc->irqs_unhandled = 0;
+#ifdef CONFIG_SMP
+ desc->affinity = CPU_MASK_ALL;
+#endif
+ spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+/**
+ * dynamic_irq_cleanup - cleanup a dynamically allocated irq
+ * @irq: irq number to initialize
+ */
+void dynamic_irq_cleanup(unsigned int irq)
+{
+ struct irq_desc *desc;
+ unsigned long flags;
+
+ if (irq >= NR_IRQS) {
+ printk(KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
+ WARN_ON(1);
+ return;
+ }
+
+ desc = irq_desc + irq;
+ spin_lock_irqsave(&desc->lock, flags);
+ desc->handle_irq = handle_bad_irq;
+ desc->chip = &no_irq_chip;
+ spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+
+/**
* set_irq_chip - set the irq chip for an irq
* @irq: irq number
* @chip: pointer to irq chip description structure