kernel_optimize_test/kernel/irq/handle.c
Ingo Molnar d1bef4ed5f [PATCH] genirq: rename desc->handler to desc->chip
This patch-queue improves the generic IRQ layer to be truly generic, by adding
various abstractions and features to it, without impacting existing
functionality.

While the queue can be best described as "fix and improve everything in the
generic IRQ layer that we could think of", and thus it consists of many
smaller features and lots of cleanups, the one feature that stands out most is
the new 'irq chip' abstraction.

The irq-chip abstraction is about describing and coding and IRQ controller
driver by mapping its raw hardware capabilities [and quirks, if needed] in a
straightforward way, without having to think about "IRQ flow"
(level/edge/etc.) type of details.

This stands in contrast with the current 'irq-type' model of genirq
architectures, which 'mixes' raw hardware capabilities with 'flow' details.
The patchset supports both types of irq controller designs at once, and
converts i386 and x86_64 to the new irq-chip design.

As a bonus side-effect of the irq-chip approach, chained interrupt controllers
(master/slave PIC constructs, etc.) are now supported by design as well.

The end result of this patchset intends to be simpler architecture-level code
and more consolidation between architectures.

We reused many bits of code and many concepts from Russell King's ARM IRQ
layer, the merging of which was one of the motivations for this patchset.

This patch:

rename desc->handler to desc->chip.

Originally i did not want to do this, because it's a big patch.  But having
both "desc->handler", "desc->handle_irq" and "action->handler" caused a
large degree of confusion and made the code appear alot less clean than it
truly is.

I have also attempted a dual approach as well by introducing a
desc->chip alias - but that just wasnt robust enough and broke
frequently.

So lets get over with this quickly.  The conversion was done automatically
via scripts and converts all the code in the kernel.

This renaming patch is the first one amongst the patches, so that the
remaining patches can stay flexible and can be merged and split up
without having some big monolithic patch act as a merge barrier.

[akpm@osdl.org: build fix]
[akpm@osdl.org: another build fix]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-29 10:26:21 -07:00

196 lines
4.8 KiB
C

/*
* linux/kernel/irq/handle.c
*
* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
*
* This file contains the core interrupt handling code.
*/
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include "internals.h"
/*
* Linux has a controller-independent interrupt architecture.
* Every controller has a 'controller-template', that is used
* by the main code to do the right thing. Each driver-visible
* interrupt source is transparently wired to the apropriate
* controller. Thus drivers need not be aware of the
* interrupt-controller.
*
* The code is designed to be easily extended with new/different
* interrupt controllers, without having to do assembly magic or
* having to touch the generic code.
*
* Controller mappings for all interrupt sources:
*/
irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
[0 ... NR_IRQS-1] = {
.status = IRQ_DISABLED,
.chip = &no_irq_type,
.lock = SPIN_LOCK_UNLOCKED
}
};
/*
* Generic 'no controller' code
*/
static void end_none(unsigned int irq) { }
static void enable_none(unsigned int irq) { }
static void disable_none(unsigned int irq) { }
static void shutdown_none(unsigned int irq) { }
static unsigned int startup_none(unsigned int irq) { return 0; }
static void ack_none(unsigned int irq)
{
/*
* 'what should we do if we get a hw irq event on an illegal vector'.
* each architecture has to answer this themself.
*/
ack_bad_irq(irq);
}
struct hw_interrupt_type no_irq_type = {
.typename = "none",
.startup = startup_none,
.shutdown = shutdown_none,
.enable = enable_none,
.disable = disable_none,
.ack = ack_none,
.end = end_none,
.set_affinity = NULL
};
/*
* Special, empty irq handler:
*/
irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
{
return IRQ_NONE;
}
/*
* Have got an event to handle:
*/
fastcall irqreturn_t handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
struct irqaction *action)
{
irqreturn_t ret, retval = IRQ_NONE;
unsigned int status = 0;
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();
do {
ret = action->handler(irq, action->dev_id, regs);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
add_interrupt_randomness(irq);
local_irq_disable();
return retval;
}
/*
* do_IRQ handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*/
fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs)
{
irq_desc_t *desc = irq_desc + irq;
struct irqaction * action;
unsigned int status;
kstat_this_cpu.irqs[irq]++;
if (CHECK_IRQ_PER_CPU(desc->status)) {
irqreturn_t action_ret;
/*
* No locking required for CPU-local interrupts:
*/
if (desc->chip->ack)
desc->chip->ack(irq);
action_ret = handle_IRQ_event(irq, regs, desc->action);
desc->chip->end(irq);
return 1;
}
spin_lock(&desc->lock);
if (desc->chip->ack)
desc->chip->ack(irq);
/*
* REPLAY is when Linux resends an IRQ that was dropped earlier
* WAITING is used by probe to mark irqs that are being tested
*/
status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
status |= IRQ_PENDING; /* we _want_ to handle it */
/*
* If the IRQ is disabled for whatever reason, we cannot
* use the action we have.
*/
action = NULL;
if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
action = desc->action;
status &= ~IRQ_PENDING; /* we commit to handling */
status |= IRQ_INPROGRESS; /* we are handling it */
}
desc->status = status;
/*
* If there is no IRQ handler or it was disabled, exit early.
* Since we set PENDING, if another processor is handling
* a different instance of this same irq, the other processor
* will take care of it.
*/
if (unlikely(!action))
goto out;
/*
* Edge triggered interrupts need to remember
* pending events.
* This applies to any hw interrupts that allow a second
* instance of the same irq to arrive while we are in do_IRQ
* or in the handler. But the code here only handles the _second_
* instance of the irq, not the third or fourth. So it is mostly
* useful for irq hardware that does not mask cleanly in an
* SMP environment.
*/
for (;;) {
irqreturn_t action_ret;
spin_unlock(&desc->lock);
action_ret = handle_IRQ_event(irq, regs, action);
spin_lock(&desc->lock);
if (!noirqdebug)
note_interrupt(irq, desc, action_ret, regs);
if (likely(!(desc->status & IRQ_PENDING)))
break;
desc->status &= ~IRQ_PENDING;
}
desc->status &= ~IRQ_INPROGRESS;
out:
/*
* The ->end() handler has to deal with interrupts which got
* disabled while the handler was running.
*/
desc->chip->end(irq);
spin_unlock(&desc->lock);
return 1;
}