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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/Kconfig
config 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=%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=%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.mk
LOCAL_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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