这篇文章的app程序是参考国嵌的。
在编写app之前我们要编译好madplay
准备工作一:
编译madplay
首先解压三个压缩文件
[root@localhost ~]# cd /work/projects/sound/
[root@localhost sound]# ls
libid3tag-0.15.1b.tar.gz libmad-0.15.1b.tar.gz madplay-0.15.2b.tar.gz
[root@localhost sound]# tar xzf libid3tag-0.15.1b.tar.gz //从名字上看是个库
[root@localhost sound]# tar xzf libmad-0.15.1b.tar.gz //这个也是库
[root@localhost sound]# tar xzf madplay-0.15.2b.tar.gz //这个是应用程序,它依赖这两个库
[root@localhost sound]#
[root@localhost sound]# cd libid3tag-0.15.1b
[root@localhost libid3tag-0.15.1b]# ./configure--host=arm-linux --prefix=/work/projects/sound/tmp
configure: WARNING: If you wanted to set the --build type, don't use--host.
If a cross compiler isdetected then cross compile mode will be used.
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
然后再
make
make install
再按照上面的方法进入libmad-0.15.1b文件夹编译
./configure --host=arm-linux --prefix=/work/projects/sound/tmpLDFLAGS="-L/work/projects/sound/tmp/lib" CFLAGS="-I/work/projects/sound/tmp/include"
注意: -L/work…..
这个-L与/之间没有空格.
然后再
make
make install
把tmp/bin/* tmp/lib/*so* -d把库文件复制到开发板lib文件夹,bin文件复制到开发板的bin文件夹
# madplay --tty-control /mnt/mp3/beyond.mp3
MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 RobertLeslie et al.
s3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
Artist: Beyond£¨»Æ¼Ò¾Ô£©
Album:ÒôÀÖµîÌÃMusicPalace
Comment:http://music.zkinfo.ha.cn
s3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
到这里时候测试下自己的开发板能否播放mp3音乐。
注意事项:确保自己的开发板已经有声卡了,想提高播放音乐的音量不能用madplay提供的方法(声音加大会破掉,而且音质会变得很差),如果你的开发板有QT界面直接调整音量滑块。
准备工作二:
编写开发板上的驱动程序。我的开发板是TQ2440。
key_drv_irq.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>
static int major;
static struct class *key_class;
static struct class_device *key_class_dev;
volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;
static DECLARE_WAIT_QUEUE_HEAD(button_waitq);
/* 中断事件标志, 中断服务程序将它置1,third_drv_read将它清0 */
static volatile int ev_press = 0;
struct pin_desc{
unsigned int pin;
unsigned int key_val;
};
/* 键值: 按下时, 0x01, 0x02, 0x03, 0x04 */
/* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 */
static unsigned char key_val;
struct pin_desc pins_desc[4] = {
{S3C2410_GPF1, 0x01},
{S3C2410_GPF4, 0x02},
{S3C2410_GPF2, 0x03},
{S3C2410_GPF0, 0x04},
};
/*
* 确定按键值
*/
static irqreturn_t buttons_irq(int irq, void *dev_id)
{
struct pin_desc * pindesc = (struct pin_desc *)dev_id;
unsigned int pinval;
pinval = s3c2410_gpio_getpin(pindesc->pin);
if (pinval)
{
/* 松开 */
key_val = 0x80 | pindesc->key_val;
}
else
{
/* 按下 */
key_val = pindesc->key_val;
}
ev_press = 1; /* 表示中断发生了 */
wake_up_interruptible(&button_waitq); /* 唤醒休眠的进程 */
return IRQ_RETVAL(IRQ_HANDLED);
}
static int key_drv_open(struct inode *inode, struct file *file)
{
/* 配置成输入模式 */
request_irq(IRQ_EINT1, buttons_irq, IRQT_BOTHEDGE, "K1", &pins_desc[0]);
request_irq(IRQ_EINT4, buttons_irq, IRQT_BOTHEDGE, "K2", &pins_desc[1]);
request_irq(IRQ_EINT2, buttons_irq, IRQT_BOTHEDGE, "K3", &pins_desc[2]);
request_irq(IRQ_EINT0, buttons_irq, IRQT_BOTHEDGE, "K4", &pins_desc[3]);
return 0;
}
static ssize_t key_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
if (size != 1)
return -EINVAL;
/* 如果没有按键动作, 休眠 */
wait_event_interruptible(button_waitq, ev_press);
/* 如果有按键动作, 返回键值 */
copy_to_user(buf, &key_val, 1);
ev_press = 0;
return 1;
}
int key_dev_close(struct inode *inode, struct file *file)
{
free_irq(IRQ_EINT1, &pins_desc[0]);
free_irq(IRQ_EINT4, &pins_desc[1]);
free_irq(IRQ_EINT2, &pins_desc[2]);
free_irq(IRQ_EINT0, &pins_desc[3]);
return 0;
}
static struct file_operations key_drv_fops={
.owner=THIS_MODULE,
.open=key_drv_open,
.read=key_drv_read,
.release=key_dev_close,
};
static int key_drv_init(void)
{
major=register_chrdev(0, "key_drv", &key_drv_fops);
key_class=class_create(THIS_MODULE, "keydrv");
key_class_dev=class_device_create(key_class, NULL, MKDEV(major,0), NULL,"buttons"); /* dev/buttons */
gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16); //0x56000010是的GPIOB的
gpfdat = gpfcon + 1;
return 0;
}
static void key_drv_exit(void)
{
unregister_chrdev(major, "key_drv");
class_device_unregister(key_class_dev);
class_destroy(key_class); //class_destory(key_class);
iounmap(gpfcon);
}
module_init(key_drv_init);
module_exit(key_drv_exit);
MODULE_LICENSE("GPL");
编译成ko文件,然后安装到开发板上。
准备工作三:
app-mp3.c
/*
* mp3播放器控制程序
* 功能:
k1:播放、暂停
k2:停止播放
k3:上一首
k4:下一首
* 附加:歌曲自动循环播放
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/select.h>
#include <sys/time.h>
#include <errno.h>
#include <sys/wait.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/shm.h>
/*共享内存申请标记*/
#define PERM S_IRUSR|S_IWUSR
/*双向循环列表:存放歌曲名*/
struct song
{
char songname[20];
struct song *prev;
struct song *next;
};
/*孙子进程id号*/
pid_t gradchild;
/*子进程id号*/
pid_t pid;
/*共享内存描述标记*/
int shmid;
char *p_addr;
/*播放标记*/
int first_key=1;
int play_flag=0;
/*************************************************
Function name: play
Parameter : struct song *
Description : 播放函数
Return : void
Argument : void
Autor & date : ada 09,12,07
**************************************************/
void play(struct song *currentsong)
{
pid_t fd;
char *c_addr;
char *p;
int len;
char my_song[30]="/mp3/";
while(currentsong)
{
/*创建子进程,即孙子进程*/
fd = fork();
if(fd == -1)
{
perror("fork");
exit(1);
}
else if(fd == 0)
{
/*把歌曲名加上根路径*/
strcat(my_song,currentsong->songname);
p = my_song;
len = strlen(p);
/*去掉文件名最后的'\n'*/
my_song[len-1]='\0';
printf("THIS SONG IS %s\n",my_song);
execl("/bin/madplay","madplay",my_song,NULL);
printf("\n\n\n");
}
else
{
/*内存映射*/
c_addr = shmat(shmid,0,0);
/*把孙子进程的id和当前播放歌曲的节点指针传入共享内存*/
memcpy(c_addr,&fd,sizeof(pid_t));
memcpy(c_addr + sizeof(pid_t)+1,¤tsong,4);
/*使用wait阻塞孙子进程,直到孙子进程播放完才能被唤醒;
当被唤醒时,表示播放MP3期间没有按键按下,则继续顺序播放下一首MP3*/
if(fd == wait(NULL))
{
currentsong = currentsong->next;
printf("THE NEXT SONG IS %s\n",currentsong->songname);
}
}
}
}
/*************************************************
Function name: creat_song_list
Parameter : void
Description : 创建歌曲名的双向循环链表
Return : struct song *
Argument : void
Autor & date : ada 09.12.07
**************************************************/
struct song *creat_song_list(void)
{
FILE *fd;
size_t size;
size_t len;
char *line = NULL;
struct song *head;
struct song *p1;
struct song *p2;
system("ls /mp3 >song_list");
fd = fopen("song_list","r");
p1 = (struct song *)malloc(sizeof(struct song));
printf("==================================song list=====================================\n");
system("ls /mp3");
printf("\n");
printf("================================================================================\n");
size = getline(&line,&len,fd);
strncpy(p1->songname,line,strlen(line));
head = p1;
while((size = getline(&line,&len,fd)) != -1)
{
p2 = p1;
p1 = (struct song *)malloc(sizeof(struct song));
strncpy(p1->songname,line,strlen(line));
p2->next = p1;
p1->prev = p2;
}
p1->next = head;
head->prev = p1;
p1 = NULL;
p2 = NULL;
system("rm -rf song_list");
return head;
}
/*************************************************
Function name: startplay
Parameter : pid_t *,struct song *
Description : 开始播放函数
Return : void
Argument : void
Autor & date : ada 09.12.07
**************************************************/
void startplay(pid_t *childpid,struct song *my_song)
{
pid_t pid;
int ret;
/*创建子进程*/
pid = fork();
if(pid > 0)
{
*childpid = pid;
play_flag = 1;
sleep(1);
/*把孙子进程的pid传给父进程*/
memcpy(&gradchild,p_addr,sizeof(pid_t));
}
else if(0 == pid)
{
/*子进程播放MP3函数*/
play(my_song);
}
}
/*************************************************
Function name: my_pause
Parameter : pid_t
Description : 暂停函数
Return : void
Argument : void
Autor & date : ada 09,12,07
**************************************************/
void my_pause(pid_t pid)
{
printf("=======================PAUSE!PRESS K1 TO CONTINUE===================\n");
kill(pid,SIGSTOP); //对孙子进程发送SKGSTOP信号
play_flag = 0;
}
/*************************************************
Function name: my_pause
Parameter : pid_t
Description : 停止播放函数
Return : void
Argument : void
Autor & date : ada 09,12,07
**************************************************/
void my_stop(pid_t g_pid)
{
printf("=======================STOP!PRESS K1 TO START PLAY===================\n");
kill(g_pid,SIGKILL); //对孙子进程发送SKGKILL信号
kill(pid,SIGKILL); //对子进程发送SKGKILL信号
first_key=1;
}
/*************************************************
Function name: conti_play
Parameter : pid_t
Description : 继续函数
Return : void
Argument : void
Autor & date : ada 09,12,07
**************************************************/
void conti_play(pid_t pid)
{
printf("===============================CONTINUE=============================\n");
kill(pid,SIGCONT); //对孙子进程发送SIGCONT信号
play_flag=1;
}
/*************************************************
Function name: next
Parameter : pid_t
Description : 下一首函数
Return : void
Argument : void
Autor & date : ada 09.12.07
**************************************************/
void next(pid_t next_pid)
{
struct song *nextsong;
printf("===============================NEXT MP3=============================\n");
/*从共享内存获得孙子进程播放歌曲的节点指针*/
memcpy(&nextsong,p_addr + sizeof(pid_t)+1,4);
/*指向下首歌曲的节点*/
nextsong = nextsong->next;
/*杀死当前歌曲播放的子进程,孙子进程*/
kill(pid,SIGKILL);
kill(next_pid,SIGKILL);
wait(NULL);
startplay(&pid,nextsong);
}
/*************************************************
Function name: prev
Parameter : pid_t
Description : 上一首函数
Return : void
Argument : void
Autor & date : yuanhui 09.12.08
**************************************************/
void prev(pid_t prev_pid)
{
struct song *prevsong;
/*从共享内存获得孙子进程播放歌曲的节点指针*/
printf("===============================PRIOR MP3=============================\n");
memcpy(&prevsong,p_addr + sizeof(pid_t)+1,4);
/*指向上首歌曲的节点*/
prevsong = prevsong->prev;
/*杀死当前歌曲播放的子进程,孙子进程*/
kill(pid,SIGKILL);
kill(prev_pid,SIGKILL);
wait(NULL);
//linux C中的wait(NULL)是什么意思?请问_百度知道
//答:等待子进程退出。NULL的意思是退出状态不关注。如果要获取退出状态应该写成wait(&status);
startplay(&pid,prevsong);
}
/*************************************************
Function name: main
Parameter : void
Description : 主函数
Return : int
Argument : void
Autor & date : ada 09.12.07
**************************************************/
int main(void)
{
int buttons_fd;
int key_value;
struct song *head;
/*打开设备文件*/
buttons_fd = open("/dev/buttons", O_RDWR);
if (buttons_fd < 0) {
perror("open /dev/buttons fail!!!");
exit(1);
}
/*创建播放列表*/
head = creat_song_list();
printf("===================================OPTION=======================================\n\n\n\n");
printf(" K1:START/PAUSE K2:STOP K3:NEXT K4:PRIOR\n\n\n\n");
printf("================================================================================\n");
/*共享内存:用于存放子进程ID,播放列表位置*/
if((shmid = shmget(IPC_PRIVATE,5,PERM))== -1)
exit(1);
p_addr = shmat(shmid,0,0);
memset(p_addr,'\0',1024);
while(1)
{
unsigned char key_value;
read(buttons_fd, &key_value, 1);
key_value--;
/*首次播放,必须是按键1*/
if(first_key) {
switch(key_value)
{
case 0:
startplay(&pid,head);
first_key=0;
break;
case 1:
case 2:
case 3:
printf("=======================PRESS K1 TO START PLAY===================\n");
break;
default:
printf("=======================PRESS K1 TO START PLAY===================\n");
break;
} //end switch
}//end if(first_key)
/*若不是首次播放,则根据不同键值处理*/
else if(!first_key) {
switch(key_value)
{
case 0:
//printf("play_flag:%d\n",play_flag);
if(play_flag)
my_pause(gradchild);
else
conti_play(gradchild);
break;
case 1:
my_stop(gradchild);
break;
case 2:
next(gradchild);
break;
case 3:
prev(gradchild);
break;
} //end switch
}//end if(!first_key)
}
close(buttons_fd);
return 0;
}
准备工作四:
在开发板根目录建立mp3文件夹,拷贝几首MP3文件进去,注意文件名不要超过20个字符。
现在可以运行这个app-mp3应用程序了。
=======================PRESS K1 TO START PLAY===================
=======================PRESS K1 TO START PLAY===================
=======================PRESS K1 TO START PLAY===================
THIS SONG IS /mp3/Tank.mp3
MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
s3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
Title: 贩贩贩 Artist: Tank(贩s3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
===============================NEXT MP3=============================
THIS SONG IS /mp3/beyond.mp3
MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
s3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
Artist: Beyond(黄家驹)
Album: 音乐殿堂Musics3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
Palace
Comment: http://music.zkinfo.ha.cn
error: frame 12346: lost synchronization
12346 frames decoded (0:05:22.5), +0.6 dB peak amplitude, 19 clipped samples
THE NEXT SONG IS huanghun.mp3
THIS SONG IS /mp3/huanghun.mp3
MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
s3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
Title: 黄昏
Artist: 周传雄 (小刚)
s3c2410-uda1341-superlp: audio_set_dsp_speed:44100 prescaler:66
Album: transfer
Year: 2000
Genre: Pop
Comment: mp3.attin.com