Android 驱动开发系列二

最近琐碎事太多了，都没什么时间来写blog。现在继续写这个android驱动的开发调试

这一章主要是讲如何测试驱动。

1、驱动的简单测试

在上一篇文章中，我们已经把添加驱动模块做完了，并把驱动下载到了板子上。下面将介绍一下如何测试驱动是否正常。

这个ttt驱动，我们实现了一个读、一个写的接口，就此进行简单的测试：

启动板子，进入系统，然后进入命令行（可以用串口，也可以用adb shell）

进入dev目录：

root@android:/ # cd /dev
root@android:/dev #

查看 ttt 设备文件是否存在：

root@android:/dev # ls -l ttt
crw------- root     root     249,   0 2013-04-02 09:58 ttt

进入到/proc目录，验证设备的输入输出：

root@android:/dev # cd /proc/
root@android:/proc #

获取 ttt 设备的值：

root@android:/proc # cat ttt
0
root@android:/proc #

设置 ttt 设备的值：

root@android:/proc # echo '111' > ttt
root@android:/proc # cat ttt
111
root@android:/proc #

这里就可以说明： ttt 设备文件已经OK了，输入输出接口都没有问题。

当然，这里还有其他的方式去验证这个输入输出，如：

进入到 /sys/class 的 ttt 设备目录下：

root@android:/proc # cd /sys/class/ttt/ttt/
root@android:/sys/class/ttt/ttt # ls
dev
power
subsystem
uevent
val
root@android:/sys/class/ttt/ttt #

通过访问 val 属性文件来读写 ttt 设备的值：

root@android:/sys/class/ttt/ttt # ls
dev
power
subsystem
uevent
val
root@android:/sys/class/ttt/ttt # cat val
111
root@android:/sys/class/ttt/ttt # echo '123' > val
root@android:/sys/class/ttt/ttt # cat val
123
root@android:/sys/class/ttt/ttt #

2、编写C程序来测试驱动的读写

切换到root权限，并进入到android源码目录下的 external 目录：

root@brantyou-ubuntu:~# cd workspace/android-4.0.4_r1.2/external/
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2/external# ls
android-mock    freetype                 libpng         safe-iop
antlr           fsck_msdos               libvpx         skia
apache-harmony  genext2fs                libxml2        sonivox
apache-http     giflib                   libxslt        speex
apache-xml      google-diff-match-patch  libyuv         sqlite
astl            grub                     llvm           srec
bison           gtest                    lohit-fonts    srtp
blktrace        guava                    markdown       stlport
bluetooth       harfbuzz                 mesa3d         strace
bouncycastle    hyphenation              mksh           svox
bsdiff          icu4c                    mockwebserver  tagsoup
bzip2           iproute2                 mtpd           tcpdump
chromium        ipsec-tools              netcat         tinyalsa
clang           iptables                 netperf        tinyxml
collada         javasqlite               neven          tremolo
dbus            javassist                nist-sip       v8
dhcpcd          jdiff                    oauth          valgrind
dnsmasq         jhead                    opencv         webkit
doclava         jpeg                     openssl        webp
dropbear        jsilver                  oprofile       webrtc
e2fsprogs       jsr305                   pcre           wpa_supplicant
easymock        junit                    ping           wpa_supplicant_6
elfutils        kernel-headers           ping6          wpa_supplicant_8
embunit         libffi                   ppp            xmlwriter
emma            libgsm                   proguard       yaffs2
esd             liblzf                   protobuf       yapp
expat           libnfc-nxp               qemu           zlib
eyes-free       libnl-headers            qemu-pc-bios
fdlibm          libpcap                  quake
flac            libphonenumber           replicaisland
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2/external#

由于这个目录下的文件比较多，为了不混淆，我另外新建了一个yapp目录，用于存放相关的程序。

进入到yapp目录，并创建 tttapp 目录：

root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2/external/yapp# mkdir tttapp
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2/external/yapp# ls
helloapp  helloworld  tttapp

进入到 tttapp 目录，并创建 tttapp.c 文件：

root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2/external/yapp# cd tttapp/
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2/external/yapp/tttapp# gedit tttapp.c

tttapp.c 文件内容如下：

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#define DEVICE_NAME     "/dev/ttt"
int main(int argc, char** argv)
{
int fd = -1;
int val = 0;
fd = open(DEVICE_NAME, O_RDWR);
if(fd == -1){
printf("Failed to open device %s.\n", DEVICE_NAME);
return -1;
}
printf("Read original value:\n");
read(fd, &val, sizeof(val));
printf("%d.\n\n", val);
val = 100;
printf("Write value %d to %s.\n\n", val, DEVICE_NAME);
write(fd, &val, sizeof(val));
printf("Read the value again:\n");
read(fd, &val, sizeof(val));
printf("%d.\n\n", val);
close(fd);
return 0;
}

创建对应的Android.mk配置文件：

root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2/external/yapp/tttapp# gedit Android.mk

Android.mk 文件内容如下：

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE := tttapp
LOCAL_SRC_FILES := tttapp.c
include $(BUILD_EXECUTABLE)

C程序编写完了，下面进行编译：

回到android的源码目录，并执行envsetup.sh：

root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2# ls
abi       build        device      hardware  out       system
bionic    cts          docs        libcore   packages  v8.log
bootable  dalvik       external    Makefile  prebuilt  vendor
boot.img  development  frameworks  ndk       sdk
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2# . build/envsetup.sh
including device/moto/stingray/vendorsetup.sh
including device/moto/wingray/vendorsetup.sh
including device/samsung/crespo4g/vendorsetup.sh
including device/samsung/crespo/vendorsetup.sh
including device/samsung/maguro/vendorsetup.sh
including device/samsung/smdkc110/vendorsetup.sh
including device/samsung/smdkv210/vendorsetup.sh
including device/samsung/torospr/vendorsetup.sh
including device/samsung/toro/vendorsetup.sh
including device/samsung/tuna/vendorsetup.sh
including device/ti/panda/vendorsetup.sh
including sdk/bash_completion/adb.bash
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2#

执行 make tttapp 编译 tttapp 程序：

root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2# make tttapp
============================================
PLATFORM_VERSION_CODENAME=REL
PLATFORM_VERSION=4.0.4
TARGET_PRODUCT=full
TARGET_BUILD_VARIANT=eng
TARGET_BUILD_TYPE=release
TARGET_BUILD_APPS=
TARGET_ARCH=arm
TARGET_ARCH_VARIANT=armv7-a
HOST_ARCH=x86
HOST_OS=linux
HOST_BUILD_TYPE=release
BUILD_ID=IMM76I
============================================
target thumb C: tttapp <= external/yapp/tttapp/tttapp.c
target Executable: tttapp (out/target/product/generic/obj/EXECUTABLES/tttapp_intermediates/LINKED/tttapp)
target Symbolic: tttapp (out/target/product/generic/symbols/system/bin/tttapp)
target Strip: tttapp (out/target/product/generic/obj/EXECUTABLES/tttapp_intermediates/tttapp)
Install: out/target/product/generic/system/bin/tttapp
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2#

这样就表示编译成功了，我们看一下这个对应的执行程序是否已经生成：

root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2# ls -l out/target/product/generic/system/bin/tttapp
-rwxr-xr-x 1 root root 5524 2013-04-02 11:04 out/target/product/generic/system/bin/tttapp
root@brantyou-ubuntu:~/workspace/android-4.0.4_r1.2#

这样就表示生成了对应的可执行程序。

好，现在我们把这个生成的 tttapp 程序拷贝到 SD卡上，然后放到板子上去执行。

我这里是放到了U盘上面，从U盘中把tttapp 拷贝到板子上的/data目录中去：

root@android:/mnt # ls usb
D3GOther.exe
EBOOT.bin
EBOOT.nb0
IRDA_X.exe
LOST.DIR
MapTools.exe
NK.BIN
NK_2G.bin
NK_3G.bin
NK_3G_y.BIN
NK_src.bin
RFIDForProduce.exe
RFIDTest.exe
RFID_X.exe
STEPLDR.bin
STEPLDR.nb0
SwitchTools.exe
WINCE 6è½¯ä»¶
android-samsung-dev_20110830.tar.gz
barscan.exe
bbk
hello
htcbjwdm.inf
tttapp
ubuntu-11.10-desktop-i386.iso
å‡¯ç«‹å¾·åœ°å›¾
æœºèº«å·ç (MC60ç«¯).exe
root@android:/mnt #
root@android:/mnt # ls
asec
ext_sd
obb
sdcard
secure
usb
root@android:/mnt # cd usb/
root@android:/mnt/usb # ls
D3GOther.exe
EBOOT.bin
EBOOT.nb0
IRDA_X.exe
LOST.DIR
MapTools.exe
NK.BIN
NK_2G.bin
NK_3G.bin
NK_3G_y.BIN
NK_src.bin
RFIDForProduce.exe
RFIDTest.exe
RFID_X.exe
STEPLDR.bin
STEPLDR.nb0
SwitchTools.exe
WINCE 6è½¯ä»¶
android-samsung-dev_20110830.tar.gz
barscan.exe
bbk
hello
htcbjwdm.inf
tttapp
ubuntu-11.10-desktop-i386.iso
å‡¯ç«‹å¾·åœ°å›¾
æœºèº«å·ç (MC60ç«¯).exe
root@android:/mnt/usb # ll tttapp
----rwxr-x system   media_rw     5524 2013-04-02 11:08 tttapp
root@android:/mnt/usb # chmod 777 tttapp
root@android:/mnt/usb # ll tttapp
----rwxr-x system   media_rw     5524 2013-04-02 11:08 tttapp
root@android:/mnt/usb # cp tttapp /data
/system/bin/sh: cp: not found
127|root@android:/mnt/usb # mv tttapp /data
failed on 'tttapp' - Cross-device link
255|root@android:/mnt/usb # mv tttapp /data/tttapp
failed on 'tttapp' - Cross-device link
255|root@android:/mnt/usb # cat tttapp > /data/tttapp
root@android:/mnt/usb # ll /data/tttapp
-rw-rw-rw- root     log          5524 2013-04-02 11:14 tttapp
root@android:/mnt/usb # cd /data
root@android:/data # ./tttapp
/system/bin/sh: ./tttapp: cannot execute - Permission denied
126|root@android:/data # chmod 777 tttapp
root@android:/data # ./tttapp
[ttt]: ttt_open().
[ttt]: ttt_read().
[ttt]: ttt_write().
[ttt]: ttt_read().
[ttt]: ttt_release().
Read original value:
123.
Write value 100 to /dev/ttt.
Read the value again:
100.
root@android:/data #

拷贝的过程中，出现了一些情况，cp指令不可用，使用cat指令就OK了。由上面最后的几句信息，可以看出这个C程序成功了。测试驱动OK了。

到此，驱动的测试就完了。下一篇将会介绍编写对应的HAL硬件抽象层来访问内核驱动