ALSA在ARM（S3C6410）中的移植

软硬件平台：ARM9（S3C2410A），UDA1341, 2.6.33.1内核，arm-none-linux-gnueabi-gcc-4.3.2ASoC:ALSA为嵌入式系统提供的SOC级驱动，支持PCM，I2S和AC97。详细内容可查阅：http://www.alsa-project.org/main/index.php/ASoC （1）驱动移植2.6.33.1已经为提供了UDA134X的ALSA驱动，只需要稍微配置即可。在arch/arm/mach-s3c2410/mach-smdk2410.c中添加：static struct s3c24xx_uda134x_platform_data s3c24xx_uda134x_data = {
        .l3_clk = S3C2410_GPB（4）,
        .l3_data = S3C2410_GPB（3）,
        .l3_mode = S3C2410_GPB（2）,
        .model = UDA134X_UDA1341,
};static struct platform_device s3c24xx_uda134x = {
        .name = "s3c24xx_uda134x",
        .dev = {
                .platform_data    = &s3c24xx_uda134x_data,
        }
};在smdk2410_devices[]添加一项：&s3c24xx_uda134x配置内核选项，选中ALSA支持。更新内核，启动显示usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
usbcore: registered new interface driver snd-usb-audio
usbcore: registered new interface driver snd-usb-caiaq
No device for DAI UDA134X
No device for DAI s3c24xx-i2s
S3C24XX_UDA134X SoC Audio driver
UDA134X SoC Audio Codec
asoc: UDA134X <-> s3c24xx-i2s mapping ok
usb 1-1: new full speed USB device using s3c2410-ohci and address 2
ALSA device list:
#0: S3C24XX_UDA134X （UDA134X）驱动移植成功。可以支持板子的UDA1341，可支持我的usb声卡了。（此处也可以直接使用alsa-driver提供驱动程序，具体我没有做）（2）alsa-lib移植版本alsa-lib-1.0.22./configure --host=arm-linux --target=arm-linux --prefix=/usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/usr --enable-static --enable-shared --disable-python --with-configdir=/usr/local/share --with-plugindir=/usr/local/lib/alsa_lib编译安装，将库文件、配置文件和插件文件转移到嵌入式文件系统的对应目录上。（3）alsa-utils移植版本alsa-utils-1.0.23PKG_CONFIG_PATH="/usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/usr/lib/pkgconfig" LDFLAGS="-L/usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/armv4t/usr/lib -lpthread -lc -lgcc" CFLAGS="-I/usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/armv4t/usr/include" ./configure --host=arm-linux --target=arm-linux --prefix=/home/gyh/mybook/alsa-utils-prefix --disable-alsamixer --with-alsa-prefix=/usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/usr/lib/ --with-alsa-inc-prefix=/usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/usr/include/将/home/gyh/mybook/alsa-utils-prefix目录拷贝到嵌入式文件系统的对应目录上。（4）alsa配置在启动脚本中添加：（可能您的不需要）/bin/mkdir /dev/snd
/bin/ln -s /dev/pcmC0D0c /dev/snd/pcmC0D0c
/bin/ln -s /dev/pcmC0D0p /dev/snd/pcmC0D0p
/bin/ln -s /dev/controlC0 /dev/snd/controlC0
/bin/ln -s /dev/pcmC1D0c /dev/snd/pcmC1D0c
/bin/ln -s /dev/pcmC1D0p /dev/snd/pcmC1D0p
/bin/ln -s /dev/controlC1 /dev/snd/controlC1
/bin/ln -s /dev/seq /dev/snd/seq
/bin/ln -s /dev/timer /dev/snd/timer modprobe.conf文件内容为#for ALSA
alias char-major-116 sndoptions snd cards_limit=2
alias snd-card-0 snd-soc-uda134x #换成您自己的
alias snd-card-1 snd-usb-audio#for OSS
alias char-major-14 soundcore
alias sound-slot-0 snd-card-0#OSS Emulation by ALSA
alias sound-service-0-0 snd-mixer-oss
alias sound-service-0-1 snd-seq-oss
alias sound-service-0-3 snd-pcm-oss
alias sound-service-0-8 snd-seq-oss
alias sound-service-0-12 snd-pcm-ossalias sound-slot-1 snd-card-1alias sound-service-1-0 snd-mixer-oss
alias sound-service-1-1 snd-seq-oss
alias sound-service-1-3 snd-pcm-oss
alias sound-service-1-8 snd-seq-oss
alias sound-service-1-12 snd-pcm-ossoptions snd-soc-uda134x index=0
options snd-usb-audio index=1 asound.conf里内容为# asoc:uda134x

pcm.！dmix {
        type dmix
        ipc_key 5678293
        ipc_key_add_uid yes
        slave {
                pcm "hw:0,0"
                period_time 0
                period_size 2048
                buffer_size 16384
                format S16_LE
                rate 48000
        }
}

pcm.！dsnoop {
        type dsnoop
        ipc_key 5778293
        ipc_key_add_uid yes
        slave {
                pcm "hw:0,0"
                period_time 0
                period_size 2048
                buffer_size 16384
                format S16_LE
                rate 48000
        }
}

pcm.asymed {
        type asym
        playback.pcm "dmix"
        capture.pcm "dsnoop"
}

pcm.！default {
        type plug
        slave.pcm "asymed"
}

pcm.dsp0 {
        type plug
        slave.pcm "asymed"
}

ctl.mixer0 {
        type hw
        card 0
} （5）测试放音和录音./aplay try.wav &显示Playing WAVE "try.wav" : Signed 16 bit Little .....听到音乐了。 ./arecord -t wav -f dat myrecord.wav显示mapped channel 9 to 1Recording WAVE "myrecord.wav" : Signed 16 bit Little Endian, Rate 48000 Hz, Steo
对着麦克风说话，ctrl+C停止./aplay myrecord.wav听到刚才说的话。设置音量./amixer set Master 50%./amixer set Capture 50%./alsactl store -f asound.state在开机启动脚本中增加脚本使每次开机恢复设置，我增加的脚本如下：/home/gyh/mybook/alsa-utils-prefix/sbin/alsactl restore -f /home/gyh/mybook/alsa-utils-prefix/sbin/asound.state