【Android驱动开发之Hello实例】归志宁无五亩园，读书本意在元元。这篇文章主要讲述Android驱动开发之Hello实例相关的知识，希望能为你提供帮助。
android驱动开发之Hello实例：
驱动部分
modified:
kernel/arch/arm/configs/msm8909-1gb_w100_hd720p-perf_defconfig
modified:
kernel/arch/arm/configs/msm8909-1gb_w100_hd720p_defconfig
modified:
kernel/drivers/input/misc/Kconfig
modified:
kernel/drivers/input/misc/Makefile
kernel/drivers/input/misc/hello.c
FFBM部分：用来测试驱动是否正常运行
modified:
vendor/qcom/proprietary/common/build/fastmmi/mmi.mk
modified:
vendor/qcom/proprietary/fastmmi/res/config/mmi-W200_W.cfg
modified:
vendor/qcom/proprietary/fastmmi/res/layout/Android.mk
modified:
vendor/qcom/proprietary/fastmmi/res/values/strings.xml
vendor/qcom/proprietary/fastmmi/module/hello/
vendor/qcom/proprietary/fastmmi/module/hello/Android.mk
vendor/qcom/proprietary/fastmmi/module/hello/hello.cpp
vendor/qcom/proprietary/fastmmi/res/layout/layout_hello.xml
SELinux安全，用来允许mmi访问/dev/hello节点modified:
device/qcom/sepolicy/common/mmi.te
modified:
external/sepolicy/device.te
modified:
external/sepolicy/file_contexts
1) kernel/drivers/input/misc/hello.c
#include <
linux/types.h>
#include <
linux/module.h>
#include <
linux/fs.h>
#include <
linux/init.h>
#include <
linux/cdev.h>
#include <
linux/device.h>
#include <
linux/slab.h>
#include <
asm/uaccess.h>
MODULE_AUTHOR("zhaopuqing");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION("hello v1.0");
MODULE_ALIAS("Hello");
#define DEVICE_SUM 1
static int hello_open(struct inode *inode, struct file *filp);
static int hello_release(struct inode *, struct file *filp);
static ssize_t hello_read(struct file*, char*, size_t, loff_t*);
static ssize_t hello_write(struct file*, const char*, size_t, loff_t*);
/*the major device number*/
static int hello_major = 0;
static int hello_minor = 0;
static struct class* hello_class = NULL;
/*init the file_operations structure*/
struct file_operations hello_fops = {
.owner = THIS_MODULE,
.open = hello_open,
.release = hello_release,
.read = hello_read,
.write = hello_write,
};
struct cdev *cdev;
static int global_var = 0;
/*global var*/
/*module init*/
static int __init hello_init(void){
int ret = 0;
struct device* temp = NULL;
dev_t devno = 0;
printk("hello:hello_init.\n");
ret = alloc_chrdev_region(&
devno, hello_minor, DEVICE_SUM, "hello");
if(ret <
0){
printk(KERN_ALERT"hello:Failed to alloc char dev region.\n");
goto fail;
}
hello_major = MAJOR(devno);
hello_minor = MINOR(devno);
cdev = cdev_alloc();
cdev->
owner = THIS_MODULE;
cdev->
ops = &
hello_fops;
if((ret = cdev_add(cdev, devno, 1))){
printk(KERN_NOTICE"Hello:Error%d adding hello.\n", ret);
return 0;
}else{
printk(KERN_ALERT"hello:hello register success.\n");
}
hello_class = class_create(THIS_MODULE, "hello");
if(IS_ERR(hello_class)){
ret = PTR_ERR(hello_class);
printk(KERN_ALERT"Failed to create hello class.\n");
goto destroy_cdev;
}
temp = device_create(hello_class, NULL, devno, "%s", "hello");
if(IS_ERR(temp)){
ret = PTR_ERR(temp);
printk(KERN_ALERT"Failed to create hello device.");
goto destroy_class;
}
return ret;
destroy_class:
class_destroy(hello_class);
destroy_cdev:
cdev_del(cdev);
fail:
return ret;
}
static void __exit hello_exit(void){
dev_t devno = MKDEV(hello_major, 0);
printk(KERN_ALERT"Goodbye, cruel world\n");
/*remove cdev from kernel*/
cdev_del(cdev);
/*unregister the device device driver*/
unregister_chrdev_region(devno, 1);
/*free the dev structure*/
if(cdev)
kfree(cdev);
cdev = NULL;
}
/*open device*/
static int hello_open(struct inode *inode, struct file *filp){
int ret = 0;
printk(KERN_ALERT"kernel:open success.\n");
return ret;
}
/*release device*/
static int hello_release(struct inode *inode, struct file *filp){
printk(KERN_ALERT"kernel:release success.\n");
return 0;
}
/*read device*/
static int hello_read(struct file *filp, char *buf, size_t len, loff_t *off){
printk(KERN_ALERT"kernel:reading...\n");
if(copy_to_user(buf, &
global_var, sizeof(int))){
return -EFAULT;
}
return sizeof(int);
}
/*write device*/
static ssize_t hello_write(struct file *filp, const char *buf, size_t len, loff_t *off){
printk(KERN_ALERT"kernel:writing...\n");
if(copy_from_user(&
global_var, buf, sizeof(int))){
return -EFAULT;
}
return sizeof(int);
}
/*module register*/
module_init(hello_init);
module_exit(hello_exit);
******************************************************
2)
kernel/drivers/input/misc/Kconfigconfig SENSORS_HELLO
tristate "Hello"
depends on SPI=y
help
If you say yes here you get supoort for Hello‘s
hello test.
******************************************************
3)
kernel/drivers/input/misc/Makefile
obj-$(CONFIG_SENSORS_HELLO)
+= hello.o
******************************************************
4)
kernel/arch/arm/configs/msm8909-1gb_w100_hd720p-perf_defconfig
CONFIG_SENSORS_HELLO=y
*******************************************************
5)
kernel/arch/arm/configs/msm8909-1gb_w100_hd720p_defconfig
CONFIG_SENSORS_HELLO=y
**************************************************
6)
vendor/qcom/proprietary/fastmmi/module/hello/hello.cpp#include "mmi_module.h"
#define TAG "Hello"
#define DEVICE_NAME "/dev/hello"
#define HELLO_TEST_WAIT "hello test,please waitting...."
#define HELLO_TEST_SUCCESS "hello test success!"
#define HELLO_TEST_FAILED "hello test failed!"
static const mmi_module_t* g_module;
static unordered_map <
string, string >
paras;
static void cb_function(const char *str, int size){
if(g_module != NULL){
g_module->
cb_print(paras[KEY_MODULE_NAME].c_str(),SUBCMD_MMI, str, size, PRINT);
}
}
int hello_test(){
ALOGI("%s : %s start!\n", TAG, __FUNCTION__);
int fd = -1;
int val = 0;
fd = open(DEVICE_NAME, O_RDWR);
if(fd <
= 0){
ALOGI("%s : %s open device [%s] failed!\n", TAG, __FUNCTION__, DEVICE_NAME);
return FAILED;
}
ALOGI("%s : %s start to read device info!\n", TAG, __FUNCTION__);
read(fd, &
val, sizeof(val));
ALOGI("%s : %s read value=https://www.songbingjia.com/android/%d/n", TAG, __FUNCTION__, val);
ALOGI("********************************************\n");
val = 5;
ALOGI("%s : %s start write value %d to %s\n", TAG, __FUNCTION__, val, DEVICE_NAME);
write(fd, &
val, sizeof(val));
ALOGI("*********************************************\n");
ALOGI("%s : %s read device value again!\n", TAG, __FUNCTION__);
read(fd, &
val, sizeof(val));
ALOGI("%s : %s read value=https://www.songbingjia.com/android/%d/n", TAG, __FUNCTION__, val);
close(fd);
return SUCCESS;
}
static int32_t module_init(const mmi_module_t * module, unordered_map <
string, string >
&
params){
ALOGI("%s : %s start!\n", TAG, __FUNCTION__);
if(module == NULL){
ALOGE("%s : %s NULL point received!\n", __FUNCTION__);
return FAILED;
}
return SUCCESS;
}
static int32_t module_deinit(const mmi_module_t * module){
ALOGI("%s : %s start!\n", TAG, __FUNCTION__);
if(module == NULL){
ALOGE("%s : %s NULL point received!\n", TAG, __FUNCTION__);
return FAILED;
}
return SUCCESS;
}
static int32_t module_run(const mmi_module_t * module, const char *cmd, unordered_map <
string ,string >
&
params){
int ret = FAILED;
if(!module || !cmd){
ALOGE("%s : %s NULL point received!\n", TAG, __FUNCTION__);
return FAILED;
}
g_module = module;
paras = params;
ALOGI("%s start.command : %s\n", __FUNCTION__, cmd);
cb_function(HELLO_TEST_WAIT, strlen(HELLO_TEST_WAIT));
if(!strcmp(cmd, SUBCMD_MMI)){
ret = hello_test();
if(ret != SUCCESS){
ALOGE("%s : %s open hello module failed!\n", TAG, __FUNCTION__);
cb_function(HELLO_TEST_FAILED, strlen(HELLO_TEST_FAILED));
}else{
ALOGI("%s : %s open hello module success!\n", TAG, __FUNCTION__);
cb_function(HELLO_TEST_SUCCESS, strlen(HELLO_TEST_SUCCESS));
}
}else if(!strcmp(cmd, SUBCMD_PCBA)){
}else{
ALOGE("%s : %s Invalid command : %s received!\n", TAG, __FUNCTION__, cmd);
ret = FAILED;
}
return ret;
}
static int32_t module_stop(const mmi_module_t *module){
ALOGI("%s : %s start.\n", __FUNCTION__);
if(module == NULL){
ALOGE("%s : %s NULL point received!\n", TAG, __FUNCTION__);
return FAILED;
}
pthread_kill(module->
run_pid, SIGUSR1);
return SUCCESS;
}
static struct mmi_module_methods_t module_methods = {
.module_init = module_init,
.module_deinit = module_deinit,
.module_run = module_run,
.module_stop = module_stop,
};
mmi_module_t MMI_MODULE_INFO_SYM = {
.version_major = 1,
.version_minor = 0,
.name = "Hello",
.author = "Hello test",
.methods = &
module_methods,
.module_handle = NULL,
.supported_cmd_list = NULL,
.supported_cmd_list_size = 0,
.cb_print = NULL,
.run_pid = -1,
};
*****************************************************
7)
vendor/qcom/proprietary/fastmmi/module/hello/Android.mkLOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_OWNER := qti
LOCAL_PROPRIETARY_MODULE := true
LOCAL_SRC_FILES := hello.cpp
LOCAL_MODULE := mmi_hello
LOCAL_CLANG := false
LOCAL_MODULE_TAGS := optional
LOCAL_CFLAGS := -Wall
LOCAL_C_INCLUDES := external/libcxx/include \
$(QC_PROP_ROOT)/fastmmi/libmmi
LOCAL_SHARED_LIBRARIES := libcutils libutils libmmi libhardware libc++
LOCAL_C_INCLUDES += $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr/include
ifeq ($(TARGET_COMPILE_WITH_MSM_KERNEL), true)
LOCAL_ADDITIONAL_DEPENDENCIES := $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ/usr
endif
include $(BUILD_SHARED_LIBRARY)
********************************************************
8)
vendor/qcom/proprietary/fastmmi/res/layout/layout_hello.xml<
?xml version="1.0" encoding="utf-8"?>
<
layout>
<
include layout="header.xml" />
<
button
name="instruction"
text="hello_notice"
w_rel="100"
h_rel="10"
x_rel="0"
y_rel="12"
color="0x007D7DFF" />
<
textview
name="display"
text=""
w_rel="100"
h_rel="60"
x_rel="4"
y_rel="27" />
<
include layout="footer.xml" />
<
/layout>
********************************************
9)
vendor/qcom/proprietary/fastmmi/res/values/strings.xml<
string name="hello">
Hello<
/string>
<
string name="hell_notice">
Hello test, just for test!<
/string>
**************************************************
10)
vendor/qcom/proprietary/fastmmi/res/layout/Android.mk
include $(CLEAR_VARS)
LOCAL_SRC_FILES := layout_hello.xml
LOCAL_CFLAGS := -Wall
LOCAL_MODULE := layout_hello.xml
LOCAL_MODULE_CLASS := ETC
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)/mmi/layout
include $(BUILD_PREBUILT)
***************************************************
11)
vendor/qcom/proprietary/fastmmi/res/config/mmi-W200_W.cfg[HELLO]
lib_name=mmi_hello.so
enable=1
automation=0
display_name=hello
layout=layout_hello.xml
**********************************************
12)
vendor/qcom/proprietary/common/build/fastmmi/mmi.mk
MMI += mmi_hello
MMI_RES += layout_hello.xml
************************************************
13)
external/sepolicy/device.te#hello test
type hello_device, dev_type;
************************************************
14)
external/sepolicy/file_contexts#hello test
/dev/hello
u:object_r:hello_device:s0
***************************************************
15)
device/qcom/sepolicy/common/mmi.te
allow mmi hello_device:chr_file {open read write};
以上为全部测试代码：
打印内核消息为：adb shell cat /proc/kmsg
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