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我下载了内核2.6.31.4，解压缩后用source insight导入入了整个工程，也同步了项目。
然后我搜：request_irq 的定义，发现如下结果：
./include/linux/interrupt.h
#ifdef CONFIG_GENERIC_HARDIRQS
extern int __must_check request_threaded_irq(unsigned int irq, irq_handler_t handler, irq_handler_t thread_fn, unsigned long flags, const char *name, void *dev);
static inline int __must_check request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags, const char *name, void *dev)
{
return request_threaded_irq(irq, handler, NULL, flags, name, dev);
}
extern void exit_irq_thread(void);
#else
extern int __must_check request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags, const char *name, void *dev);
/*
* Special function to avoid ifdeffery in kernel/irq/devres.c which
* gets magically built by GENERIC_HARDIRQS=n architectures (sparc,
* m68k). I really love these $@%#!* obvious Makefile references:
* ../../../kernel/irq/devres.o
*/
static inline int __must_check request_threaded_irq(unsigned int irq, irq_handler_t handler, irq_handler_t thread_fn, unsigned long flags, const char *name, void *dev)
{
return request_irq(irq, handler, flags, name, dev);
}
static inline void exit_irq_thread(void) { }
#endif
可见，如果定义了 CONFIG_GENERIC_HARDIRQS， 这段程序的 request_irq 要调 request_threaded_irq ，于是我又搜 request_threaded_irq 的定义 ，于是在：
./kernel/irq/manage.c 中找到：
/**
* request_threaded_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs.
* Primary handler for threaded interrupts
* @thread_fn: Function called from the irq handler thread
* If NULL, no irq thread is created
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
*
* This call allocates interrupt resources and enables the
* interrupt line and IRQ handling. From the point this
* call is made your handler function may be invoked. Since
* your handler function must clear any interrupt the board
* raises, you must take care both to initialise your hardware
* and to set up the interrupt handler in the right order.
*
* If you want to set up a threaded irq handler for your device
* then you need to supply @handler and @thread_fn. @handler ist
* still called in hard interrupt context and has to check
* whether the interrupt originates from the device. If yes it
* needs to disable the interrupt on the device and return
* IRQ_WAKE_THREAD which will wake up the handler thread and run
* @thread_fn. This split handler design is necessary to support
* shared interrupts.
*
* Dev_id must be globally unique. Normally the address of the
* device data structure is used as the cookie. Since the handler
* receives this value it makes sense to use it.
*
* If your interrupt is shared you must pass a non NULL dev_id
* as this is required when freeing the interrupt.
*
* Flags:
*
* IRQF_SHARED Interrupt is shared
* IRQF_DISABLED Disable local interrupts while processing
* IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
* IRQF_TRIGGER_* Specify active edge(s) or level
*
*/
int request_threaded_irq(unsigned int irq, irq_handler_t handler,
irq_handler_t thread_fn, unsigned long irqflags,
const char *devname, void *dev_id)
{
struct irqaction *action;
struct irq_desc *desc;
int retval;
/*
* handle_IRQ_event() always ignores IRQF_DISABLED except for
* the _first_ irqaction (sigh). That can cause oopsing, but
* the behavior is classified as "will not fix" so we need to
* start nudging drivers away from using that idiom.
*/
if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) == (IRQF_SHARED|IRQF_DISABLED)) {
pr_warning(
"IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
irq, devname);
}
#ifdef CONFIG_LOCKDEP
/*
* Lockdep wants atomic interrupt handlers:
*/
irqflags |= IRQF_DISABLED;
#endif
/*
* Sanity-check: shared interrupts must pass in a real dev-ID,
* otherwise we'll have trouble later trying to figure out
* which interrupt is which (messes up the interrupt freeing
* logic etc).
*/
if ((irqflags & IRQF_SHARED) && !dev_id)
return -EINVAL;
desc = irq_to_desc(irq);
if (!desc)
return -EINVAL;
if (desc->status & IRQ_NOREQUEST)
return -EINVAL;
if (!handler)
return -EINVAL;
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;
action->handler = handler;
action->thread_fn = thread_fn;
action->flags = irqflags;
action->name = devname;
action->dev_id = dev_id;
retval = __setup_irq(irq, desc, action);
if (retval)
kfree(action);
#ifdef CONFIG_DEBUG_SHIRQ
if (irqflags & IRQF_SHARED) {
/*
* It's a shared IRQ -- the driver ought to be prepared for it
* to happen immediately, so let's make sure....
* We disable the irq to make sure that a 'real' IRQ doesn't
* run in parallel with our fake.
*/
unsigned long flags;
disable_irq(irq);
local_irq_save(flags);
handler(irq, dev_id);
local_irq_restore(flags);
enable_irq(irq);
}
#endif
return retval;
}
EXPORT_SYMBOL(request_threaded_irq);
我很奇怪的是，./include/linux/interrupt.h 的头文件中并没有包含 ./kernel/irq/manage.c ，这是怎么回事，那么这个 request_threaded_irq 是那个 request_irq
调用的吗 ？
除此两处之外，整个内核再也找不到 request_irq 或 request_threaded_irq 的定义了。
不是说各自的平台有各自的 request_irq 吗，为什么我找不到？
如果没有定义 CONFIG_GENERIC_HARDIRQS，那么执行的流程如何去找 request_irq 呢？
要命的问题是：./include/linux/interrupt.h 并没有对应的 ./include/linux/interrupt.c 而其中的 函数原型却在 ./kernel/irq/manage.c 中，这是个什么原理？
内核里是用相同的名字，一个头文件对应一个.c文件吗？
急盼解答！！！版主，高手，务必伸出援手啊！！！ |
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发表于 2009-10-17 16:51
