內核atom機制
阿新 • • 發佈：2019-02-18
信號 -m reg 初始 lin order ems pos res
內核版本：linux2.6.22.6 硬件平臺：JZ2440
驅動源碼 atom_ipc_poll_key_int_drv.c ：
#include <linux/module.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/delay.h> #include <linux/irq.h> #include <asm/uaccess.h> #include <asm/irq.h> #include<asm/io.h> #include <asm/arch/regs-gpio.h> #include <asm/hardware.h> #include <linux/poll.h> static struct class *key_int_class; static struct class_device *key_int_class_device; volatile unsigned long *GPFCON=NULL; volatile unsigned long *GPFDAT=NULL; volatile unsigned long*GPGCON=NULL; volatile unsigned long *GPGDAT=NULL; static struct fasync_struct fasync_key; //定義一個 fsync 結構體 struct pin_desc { unsigned int pin; unsigned int key_val; }; static unsigned char key_val; static volatile int ev_press=0; static struct pin_desc pin_desc_array[4]={{S3C2410_GPF0,0x01},{S3C2410_GPF2,0X02},{S3C2410_GPG3,0x03},{S3C2410_GPG11,0x04}}; static DECLARE_WAIT_QUEUE_HEAD(wait_key); static atomic_t ready=ATOMIC_INIT(1); static irqreturn_t key_handler(int irq, void *dev_id) { struct pin_desc *pindesc = (struct pin_desc *)dev_id; unsigned int pinval=0; pinval = s3c2410_gpio_getpin(pindesc->pin); if(pinval) key_val = 0x08 | pindesc->key_val; else key_val = pindesc->key_val; kill_fasync(&fasync_key,SIGIO,POLL_IN); //發生中斷後 向結構體裏的PID進程 發送 SIGIO 信號 wake_up_interruptible(&wait_key); ev_press = 1; return IRQ_RETVAL(IRQ_HANDLED); } static int key_drv_open(struct inode *inode,struct file *file) { if(!atomic_dec_and_test(&ready)) { atomic_inc(&ready); return -EBUSY; } request_irq(IRQ_EINT0, key_handler,IRQT_BOTHEDGE,"KEY1", &pin_desc_array[0]); request_irq(IRQ_EINT2, key_handler,IRQT_BOTHEDGE,"KEY2", &pin_desc_array[1]); request_irq(IRQ_EINT11, key_handler,IRQT_BOTHEDGE,"KEY3",&pin_desc_array[2]); request_irq(IRQ_EINT19, key_handler,IRQT_BOTHEDGE,"KEY4",&pin_desc_array[3]); return 0; } ssize_t key_drv_read(struct file *file,const char __user *buf,size_t count,loff_t *ppos) { if (count != 1) return -EINVAL; wait_event_interruptible(wait_key,ev_press); ev_press=0; copy_to_user(buf,&key_val,1); return 1; } static int key_drv_close(struct inode *inode,struct file *file) { atomic_inc(&ready); free_irq(IRQ_EINT0, &pin_desc_array[0]); free_irq(IRQ_EINT2, &pin_desc_array[1]); free_irq(IRQ_EINT11, &pin_desc_array[2]); free_irq(IRQ_EINT19, &pin_desc_array[3]); return 0; } unsigned int key_drv_poll(struct file *file,poll_table *wait) { unsigned int mask=0; poll_wait(file,&wait_key,wait); if(ev_press) mask |= POLLIN | POLLRDNORM; return mask; } static int init_fasync(int fd,struct file *file,int on) // 初始化FASYNC 結構體 { printk("init fasync struct...\n"); return fasync_helper(fd,file,on,&fasync_key); } static struct file_operations key_drv_mode= { .owner = THIS_MODULE, .open = key_drv_open, .read = key_drv_read, .release = key_drv_close, .poll = key_drv_poll, .fasync = init_fasync, }; int major=0; static int key_drv_init(void) { major = register_chrdev(0,"atom_ipc_poll_key",&key_drv_mode); // /proc/devices key_int_class = class_create(THIS_MODULE,"key_int_class"); key_int_class_device = class_device_create(key_int_class,NULL,MKDEV(major,0),NULL,"atom_ipc_poll_key"); // /dev/key_int_drv GPFCON=(volatile unsigned long *)ioremap(0x56000050,16); GPFDAT=GPFCON+1; GPGCON=(volatile unsigned long *)ioremap(0x56000060,16); GPGDAT=GPGCON+1; return 0; } static void key_drv_exit(void) { unregister_chrdev(major,"atom_ipc_poll_key"); class_device_unregister(key_int_class_device); class_destroy(key_int_class); iounmap(GPFCON); iounmap(GPGCON); } module_init(key_drv_init); module_exit(key_drv_exit); MODULE_LICENSE("GPL");
測試應用程序 atom_ipc_poll_key_int_drv_test.c ：
#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <stdio.h> #include <poll.h> #include <signal.h> #include <sys/types.h> #include <unistd.h> #include <fcntl.h> int fd=0; void act_fun(void) // 捕獲信號響應函數 { unsigned char key_val=0; read(fd,&key_val,1); printf("key_val= %d\n",key_val); } int main(int argc,char **argv) { unsigned char key_val=0; int oflags=0; int ret; struct pollfd fds[1]; fd = open("/dev/atom_ipc_poll_key",O_RDWR); if(fd <0) { printf("error: can‘t open device :/dev/atom_ipc_poll_key\n"); return -1; } signal(SIGIO,act_fun); //捕獲信號 fcntl(fd,F_SETOWN,getpid()); //應用程 序用 fcntl 告訴fd驅動 當前應用程序的PID oflags = fcntl(fd,F_GETFL); // 獲取 fd驅動的 狀態旗標 fcntl(fd,F_SETFL,oflags|FASYNC);//更新oflags while(1) { sleep(1000); } return 0; }
Makefile文件:
KER_DIR=/work/systems/kernel/linux-2/linux-2.6.22.6 all: make -C $(KER_DIR) M=`pwd` modules clean: make -C $(KER_DIR) M=`pwd` modules clean rm -fr moudles.order obj-m +=atom_ipc_poll_key_int_drv.o
內核atom機制