SPI模块的JNI方法提供Java访问HAL层服务接口

谁借莪１个温暖的怀抱￠ 2022-08-11 16:40 187阅读 0赞

1、在frameworks/base/services/jni下创建spijni文件夹。

2、在spijni目录下创建com\_android\_server\_SpiService.cpp和Android.mk。

com\_android\_server\_SpiService.cpp

#define	LOG_TAG "SpiService"
    #include "jni.h"
    #include "JNIHelp.h"
    #include "android_runtime/AndroidRuntime.h"
    #include <utils/misc.h>
    #include <utils/Log.h>
    #include <hardware/hardware.h>
    #include <hardware/spihal.h>
    #include <stdio.h>
    #include <fcntl.h>
    
    namespace android
    {
    	/* 定义访问HAL层函数结构体 */
    	struct spi_device_t *spi_device = NULL;
    	/* 定义spi读函数 */
    	static jint spi_jni_read(JNIEnv *env, jobject clazz, jbyteArray jread_arr, jint len)
    	{
    		jbyte *array = NULL;
    		jboolean *buf;
    		int i = 0;
    
    		ALOGE("Jni Spi Read ...\n");
    		array = env->GetByteArrayElements(jread_arr, NULL);
    		if(array == NULL)
    		{
    			ALOGE("JniSpiRead: getByteArrayElements error!\n");
    			return -1;
    		}
    		buf = (jboolean *)calloc(sizeof(*array), sizeof(jboolean));
    		if(buf == NULL)
    		{
    			ALOGE("JniSpiRead: calloc error!\n");
    			return -1;
    		}
    		
    		spi_device->spi_read(spi_device, buf, len);
    		for(i = 0; i < len; i++)
    		{
    			ALOGE("Spi Jni Read: data : %#x\n",*(buf + i));
    			*(array + i) = (jchar)(*(buf + i));
    		}
    		env->ReleaseByteArrayElements(jread_arr, array, 0);
    		free(buf);
    		buf = NULL;
    		return 0;
    		
    	}
    	/* 定义spi写函数 */
    	static jint spi_jni_write(JNIEnv *env, jobject clazz, jbyteArray jwrite_arr, jint len)
    	{
    		jbyte *array = NULL;
    		jboolean *buf;
    		int i = 0;
    
    		ALOGE("Jni Spi Write ...\n");
    		array = env->GetByteArrayElements(jwrite_arr, NULL);
    		if(array == NULL)
    		{
    			ALOGE("JniSpiWrite: getByteArrayElements error!\n");
    			return -1;
    		}
    		buf = (jboolean *)calloc(sizeof(*array), sizeof(jboolean));
    		if(buf == NULL)
    		{
    			ALOGE("JniSpiWrite: calloc error!\n");
    			return -1;
    		}
    		for(i = 0; i < len; i++)
    		{
    			*(buf + i) = (jboolean)(*(array + i));
    			ALOGE("Spi Jni Write: data : %#x\n",*(buf + i));
    		}
    		env->ReleaseByteArrayElements(jwrite_arr, array, 0);
    		
    		spi_device->spi_write(spi_device, buf, len);
    		free(buf);
    		buf = NULL;
    		return 0;
    	}
    	/* 定义spi打开函数 */
    	static inline int spi_jni_open(const hw_module_t * module, struct spi_device_t **device)
    	{
    		return module->methods->open(module, SPI_HARDWARE_MODULE_ID, (struct hw_device_t **)device);
    	}
    	/* 定义spi初始化函数 */
    	static jboolean spi_jni_init(JNIEnv *env, jclass clazz)
    	{
    		spi_module_t *Jspi_module;
    		ALOGE("Spi JNI: spi initializing ...\n");
    		if(hw_get_module(SPI_HARDWARE_MODULE_ID, (const struct hw_module_t **)&Jspi_module) == 0)
    		{
    			ALOGE("Spi JNI: spi stub found.\n");
    			if(spi_jni_open(&(Jspi_module->common), &spi_device) == 0)
    			{
    				ALOGE("Spi JNI: spi device is open.\n");
    				if(spi_device)
    				{
    					spi_device->spi_init(spi_device);
    					ALOGE("Spi JNI: spi init successfuly!\n");
    					return true;
    				}
    				ALOGE("Spi JNI: spi init failed.\n");
    				return false;
    			}
    			ALOGE("Spi JNI: failed to open spi device.\n");
    			return false;
    		}
    		ALOGE("Spi JNI: failed to get spi stub module.\n");
    		return false;
    	}
    	/* JNI方法 */
    	static const JNINativeMethod method_table[] = 
    	{
    		{"native_init", "()Z", (void *)spi_jni_init},
    		{"native_write", "([BI)I", (void *)spi_jni_write},
    		{"native_read", "([BI)I", (void *)spi_jni_read},
    	};
    	/* 注册JNI方法 */
    	static int registerMethods(JNIEnv *env)
    	{
    		static const char *const kClassName = "com/android/server/SpiService";
    		jclass clazz;
    		clazz = env->FindClass(kClassName);
    		if(clazz == NULL)
    		{
    			ALOGE("Can't find class %s\n",kClassName);
    			return -1;
    		}
    		if(env->RegisterNatives(clazz,method_table, sizeof(method_table)/sizeof(method_table[0])) != JNI_OK)
    		{
    			ALOGE("Failed registering methods for %s\n",kClassName);
    			return -1;
    		}
    		return 0;
    	}
    	extern "C" 
    	
    	jint JNI_OnLoad(JavaVM *vm, void *reserved)
    	{
    		JNIEnv *env = NULL;
    		jint result = -1;
    		ALOGE("Jni OnLoad ...\n");
    		if(vm->GetEnv((void **)&env, JNI_VERSION_1_4) != JNI_OK)
    		{
    			ALOGE("ERROR: GetEnv failed .\n");
    			goto fail;
    		}
    		assert(env != NULL);
    		if(registerMethods(env) != 0)
    		{
    			ALOGE("ERROR: PlatformLibrary native registeration failed .\n");
    			goto fail;
    		}
    		result = JNI_VERSION_1_4;
    fail:
    		return result;
    	}
    };

Android.mk

LOCAL_PATH:= $(call my-dir)
    include $(CLEAR_VARS)
    
    LOCAL_SRC_FILES:= \
        com_android_server_SpiService.cpp \
    
    LOCAL_C_INCLUDES += \
        $(JNI_H_INCLUDE) \
        frameworks/base/services \
        frameworks/base/core/jni \
        external/skia/include/core \
        libcore/include \
        libcore/include/libsuspend \
    	$(call include-path-for, libhardware)/hardware \
    	$(call include-path-for, libhardware_legacy)/hardware_legacy \
    
    LOCAL_SHARED_LIBRARIES := \
        libandroid_runtime \
        libandroidfw \
        libcutils \
        liblog \
        libhardware \
        libhardware_legacy \
        libnativehelper \
        libsystem_server \
        libutils \
        libui \
        libinput \
        libskia \
        libgui \
        libusbhost \
        libsuspend
    
    ifeq ($(WITH_MALLOC_LEAK_CHECK),true)
        LOCAL_CFLAGS += -DMALLOC_LEAK_CHECK
    endif
    
    LOCAL_MODULE:= libspi_servers
    
    include $(BUILD_SHARED_LIBRARY)

3、在源码主目录下编译执行命令：mmm  frameworks/base/services/jni。

4、生成库的路径out/target/product/sabresd\_6dq/symbols/system/lib/libspi\_servers.so。

5、把生成的该库放到开发板的/system/lib目录下

加执行权限 chown  root  libspi\_servers.so

chmod  777   libspi\_servers.so

注意：如果无法打开设备节点/dev/spi1.0则

加执行权限   chown  root  spi1.0

chmod  777   spi1.0

无法加执行权限时执行：mount -o rw,remount -t ext4 /dev/block/mmcblk0p5 /system

chmod   777  /system