注册中断服务函数
中断注册是使用了<linux/interrupt.h>的"requset_irq"函数:
中断注册是使用了<linux/interrupt.h>的"requset_irq"函数:
extern int __must_check request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags, const char *name, void *dev);
| 变量 | 作用 |
|---|---|
| irq | 申请的硬件中断号 |
| handler | 向系统注册的中断处理函数,是一个回调函数,中断发生时,系统调用这个函数,dev_id参数将被传递给它 |
| *name | 中断名称,在/proc/interrupts中可以看到此名称 |
| *dev | 在中断共享时会用到,让handler知道是处理哪个中断,也可以用来指定中断服务函数需要参考的数据地址,一般设置为这个设备的设备结构体或者NULL |
| flags |
中断处理的属性,详细参数在 |
/*
/*
* These flags used only by the kernel as part of the
* irq handling routines.
*
* IRQF_DISABLED - keep irqs disabled when calling the action handler.
* DEPRECATED. This flag is a NOOP and scheduled to be removed
* IRQF_SAMPLE_RANDOM - irq is used to feed the random generator
* IRQF_SHARED - allow sharing the irq among several devices
* IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
* IRQF_TIMER - Flag to mark this interrupt as timer interrupt
* IRQF_PERCPU - Interrupt is per cpu
* IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
* IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
* registered first in an shared interrupt is considered for
* performance reasons)
* IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
* Used by threaded interrupts which need to keep the
* irq line disabled until the threaded handler has been run.
* IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
* IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
* IRQF_NO_THREAD - Interrupt cannot be threaded
*/
#define IRQF_DISABLED 0x00000020
#define IRQF_SAMPLE_RANDOM 0x00000040
#define IRQF_SHARED 0x00000080
#define IRQF_PROBE_SHARED 0x00000100
#define __IRQF_TIMER 0x00000200
#define IRQF_PERCPU 0x00000400
#define IRQF_NOBALANCING 0x00000800
#define IRQF_IRQPOLL 0x00001000
#define IRQF_ONESHOT 0x00002000
#define IRQF_NO_SUSPEND 0x00004000
#define IRQF_FORCE_RESUME 0x00008000
#define IRQF_NO_THREAD 0x00010000
#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
/*
* These flags used only by the kernel as part of the
* irq handling routines.
*
* IRQF_DISABLED - keep irqs disabled when calling the action handler.
* DEPRECATED. This flag is a NOOP and scheduled to be removed
* IRQF_SAMPLE_RANDOM - irq is used to feed the random generator
* IRQF_SHARED - allow sharing the irq among several devices
* IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
* IRQF_TIMER - Flag to mark this interrupt as timer interrupt
* IRQF_PERCPU - Interrupt is per cpu
* IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
* IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
* registered first in an shared interrupt is considered for
* performance reasons)
* IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
* Used by threaded interrupts which need to keep the
* irq line disabled until the threaded handler has been run.
* IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
* IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
* IRQF_NO_THREAD - Interrupt cannot be threaded
*/
#define IRQF_DISABLED 0x00000020
#define IRQF_SAMPLE_RANDOM 0x00000040
#define IRQF_SHARED 0x00000080
#define IRQF_PROBE_SHARED 0x00000100
#define __IRQF_TIMER 0x00000200
#define IRQF_PERCPU 0x00000400
#define IRQF_NOBALANCING 0x00000800
#define IRQF_IRQPOLL 0x00001000
#define IRQF_ONESHOT 0x00002000
#define IRQF_NO_SUSPEND 0x00004000
#define IRQF_FORCE_RESUME 0x00008000
#define IRQF_NO_THREAD 0x00010000
#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
关闭中断服务函数
extern void disable_irq(unsigned int irq);
| 变量 | 作用 |
|---|---|
| irq | 需要屏蔽的硬件中断号 |
使能中断服务函数
extern void enable_irq(unsigned int irq);
| 变量 | 作用 |
|---|---|
| irq | 需要使能硬件中断号 |
释放中断服务函数
void free_irq (unsigned int irq, void *dev_id);
| 变量 | 作用 |
|---|---|
| irq | 将要注销掉的中断服务函数的中断号； |
| dev_id | 值指定与"request_irq()"函数中使用的"dev_id"值相同的值 |
中断处理例程的返回值说明
中断处理例程应当返回一个值指示是否真正处理了一个中断.如果处理例程发现设备确实需要处理,应当返回"IRQ_HANDLED"; 否则返回值"IRQ_NONE".
下面是<linux/irqreturn.h>文件的内容,更为详细的说明.
#ifndef _LINUX_IRQRETURN_H
#define _LINUX_IRQRETURN_H
/**
* enum irqreturn
* @IRQ_NONE interrupt was not from this device
* @IRQ_HANDLED interrupt was handled by this device
* @IRQ_WAKE_THREAD handler requests to wake the handler thread
*/
enum irqreturn {
IRQ_NONE,
IRQ_HANDLED,
IRQ_WAKE_THREAD,
};
typedef enum irqreturn irqreturn_t;
#define IRQ_RETVAL(x) ((x) != IRQ_NONE)
#endif
#define _LINUX_IRQRETURN_H
/**
* enum irqreturn
* @IRQ_NONE interrupt was not from this device
* @IRQ_HANDLED interrupt was handled by this device
* @IRQ_WAKE_THREAD handler requests to wake the handler thread
*/
enum irqreturn {
IRQ_NONE,
IRQ_HANDLED,
IRQ_WAKE_THREAD,
};
typedef enum irqreturn irqreturn_t;
#define IRQ_RETVAL(x) ((x) != IRQ_NONE)
#endif
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