MTK中的nvram的操作实现

NVRAM读写操作详解在MTK中，NVRAM是作为一个独立的task来运行的。在nvram_main.c文件中，(代码有删减,注释部分用黄色标出,便于阅读)voidnvram_task_main(task_entry_struct*task_entry_ptr){kal_get_my_task_index(&my_index);/*nvramspecialservice*/nvram_special_service();while(1){//从Q中得到消息receive_msg_ext_q(task_info_g[task_entry_ptr->task_indx].task_ext_qid,¤t_ilm);stack_set_active_module_id(my_index,current_ilm.dest_mod_id); //处理消息nvram_main(¤t_ilm); //释放消息free_ilm(¤t_ilm);}}Nvram_main函数,处理NVRAM相关的消息voidnvram_main(ilm_struct*ilm_ptr){if(ilm_ptr!=NULL){if((ilm_ptr->msg_id>=MSG_ID_NVRAM_CODE_BEGIN)&&(ilm_ptr->msg_id<=MSG_ID_NVRAM_CODE_END)){if(ilm_ptr->msg_id==MSG_ID_NVRAM_STARTUP_REQ){ //STARTUP消息nvram_startup_handler(ilm_ptr);}elseif(ilm_ptr->msg_id==MSG_ID_NVRAM_RESET_REQ){ //RESET消息nvram_reset_handler(ilm_ptr);}elseif(ilm_ptr->msg_id==MSG_ID_NVRAM_READ_REQ){ nvram_read_handler(ilm_ptr); //READ消息}elseif(ilm_ptr->msg_id==MSG_ID_NVRAM_WRITE_REQ){nvram_write_handler(ilm_ptr);//WRITE消息}elseif(ilm_ptr->msg_id==MSG_ID_NVRAM_SET_LOCK_REQ){nvram_set_lock_handler(ilm_ptr);//LOCK消息,比较多用在TST中}}}/*endofmodulemainfunction*/也可以看到NVRAMtask处理几个消息.READ流程从NV中读取一个数据,例如读取语言设置信息:ReadValue(NVRAM_SETTING_LANG,&data,DS_BYTE,&error);我们需要注明,NVRAM的LID,读取数据存放的指针,数据类型,和返回错误信息的地址.#defineReadValue(nId,pBuffer,nDataType,pError)\ReadValueInt(nId,pBuffer,nDataType,pError,__FILE__,__LINE__)ReadValue精简了两个参数,不需要注明文件和第多少行,方面了应用使用.看一下ReadValueInt这个函数.我们来看看这个函数到底干了什么事情:S32ReadValueInt(U8nDataItemId,void*pBuffer,U8nDataType,S16*pError,S8*fileName,S32lineNumber){switch(nDataType){caseDS_BYTE:{ //byteDataReadFlag先记住这个标志,它标志了byte的数据是否已经被读取,所以从这里我们可以猜测,NVRAM的数据,应该不是每次都从硬件读取的,而是有缓存的(记住这个假设,稍后验证)/*secondtimereading,italwasyreturnonerequestitem*/if(byteDataReadFlag){ //这个注释就更加明白了/*DataiscachednoneedtoreadfromNVRAM*/memcpy(pBuffer,&byte_data[nDataItemId*nDataType],nDataType);status=DS_BYTE;error=NVRAM_READ_SUCCESS;}/*processfirsttimereadingalldataandreturnfirstrequestitemdata*/else{/*ReaddatafromtheNVRAMfile*/ //这才从NVRAM文件中读取 //这个BUFFER的大小,8*512=4KU8tempBuffer[NVRAM_CACHE_SIZE]; //这个函数重点分析status=ReadRecordInt(NVRAM_EF_CACHE_BYTE_LID,1,tempBuffer,sizeof(tempBuffer),&error,fileName,lineNumber);/*copyoutalltotalreadingdata*/ //把读取的数据copy到byte_data里面去memcpy(byte_data,tempBuffer,sizeof(tempBuffer)); //这个时候把这个flag置上了byteDataReadFlag=1;/*returnfirstrequestitemdata*/memcpy(pBuffer,&byte_data[nDataItemId*nDataType],nDataType);status=DS_BYTE;error=NVRAM_READ_SUCCESS;}break;}/*EndofcaseDS_BYTE*///后面的SHORT,DOUBLE同样道理caseDS_SHORT:{}/*EndofcaseDS_SHORT*/caseDS_DOUBLE:{}/*EndofcaseDS_DOUBLE*/}*pError=error;returnstatus;}ReadValueInt总结:这个函数,就是把以前读好的三个数组的数据拿出来,如果还没有从NVRAM读取到cashe里面,就读一次.关键的函数是:ReadRecordInt.第一次读BYTE类型的数据之前,三个数组都是空的,flag也是空的,读一个之后,byte数据被从NVRAM文件中读入到cashe中,放在byte的数组里面,byteflag也被置上了.下次再读的byte,就只需要从CACHE中读取就可以了.同理,short和double数据也相同.来看看它是怎么做的#defineReadRecordInt(nFileId,nRecordId,pBuffer,nBufferSize,pError,fileName,lineNumber)\AccessRecordInt(nFileId,nRecordId,pBuffer,nBufferSize,1,pError,MMI_FALSE,MMI_TRUE,fileName,lineNumber)S32AccessRecordInt(U16nFileId,U16nRecordId,void*pBuffer,U16nBufferSize,U16nRecordAmount,S16*pError,pBOOLisWrite,pBOOLisValue,S8*filename,S32lineNumber){MYQUEUEqueueNode;S32status=-1;U32my_index;circularQ_check_enumcircularQ_check_result=circularQ_check_never_check;staticU8nvram_req_count=0;MMI_BOOLtoPush;if(isWrite){//WRITE的先放一下,先看READ的再说}else{ //发了一个消息 SendNVRAMReadReq(nFileId,nRecordId,nRecordAmount);//这个函数调用了Message.oslMsgId=MSG_ID_MMI_EQ_NVRAM_READ_REQ;//OslMsgSendExtQueue(&Message),发了一个REQ消息到Q上去.}in_nvram_procedure++;//REQ消息发完了,接下来就等RSP消息来while(1){/*ifmorethan1accessrequestexist,gothroughthecircularQ*/if((nvram_req_count>0)&&(circularQ_check_result==circularQ_check_never_check)){circularQ_check_result=NVRAMCheckCircularQ(&queueNode,nFileId);}if(circularQ_check_result!=circularQ_check_found){OslReceiveMsgExtQ(mmi_ext_qid,&queueNode);OslGetMyTaskIndex(&my_index);OslStackSetActiveModuleID(my_index,MOD_MMI);}//这个标志位先置空,不管,先记住它toPush=MMI_FALSE;switch(queueNode.msg_id){//这里列出了很多消息,其他不管,先找READ_RSP消息再说caseMSG_ID_MMI_EQ_PLAY_AUDIO_RSP:caseMSG_ID_MMI_EQ_STOP_AUDIO_RSP:caseMSG_ID_MMI_EQ_EXE_GPIO_LEVEL_RSP:caseMSG_ID_MMI_EQ_SET_VOLUME_RSP:caseMSG_ID_MMI_EQ_KEYPAD_DETECT_IND:caseMSG_ID_TIMER_EXPIRY://就它了caseMSG_ID_MMI_EQ_NVRAM_READ_RSP:{mmi_eq_nvram_read_rsp_struct*readMessage;readMessage=(mmi_eq_nvram_read_rsp_struct*)queueNode.oslDataPtr;{if(readMessage->result.flag==MMI_OK){ //读成功了,再比较一下数据大小是不是合格if(readMessage->length>nBufferSize){}elseif(readMessage->length<nBufferSize){}else{memcpy(pBuffer,readMessage->data,readMessage->length);*pError=NVRAM_READ_SUCCESS;}status=readMessage->length;}OslFreeInterTaskMsg(&queueNode);}toPush=MMI_TRUE;break;}caseMSG_ID_MMI_EQ_NVRAM_WRITE_RSP:}//这个flag标志是否读取成功if(toPush==MMI_TRUE){ilm_structilm_ptr;flag=OslWriteCircularQ(&ilm_ptr);OslFreeInterTaskMsg(&queueNode);}}}AccessRecordInt总结:这个函数是个真正的读取函数,发REQ消息给NVRAMTASK,等待RSP消息,得到读取数据.写入流程重点分析WriteValueInt这个函数S32WriteValueInt(U8nDataItemId,void*pBuffer,U8nDataType,S16*pError,S8*fileName,S32lineNumber){switch(nDataType){//还拿BYTE来说caseDS_BYTE:{ //已经从NVRAM到CACHE里面了/*secondtimeaccess,italwayssetstherequestitem*/if(byteDataReadFlag){/*DataiscachednoneedtoreadfromNVRAM*/memcpy(&byte_data[nDataItemId*nDataType],pBuffer,nDataType);/*writeintoNVRAMmodule,ifnotwaitforfalshingdirectly*/if(!byteDataWriteFlashFlag){status=WriteRecordInt(NVRAM_EF_CACHE_BYTE_LID,1,byte_data,NVRAM_CACHE_SIZE,&error,fileName,lineNumber);}status=DS_BYTE;error=NVRAM_WRITE_SUCCESS;} //还没有读到CACHE里面/*processfirsttimeaccessalldataandreturnfirstwriteitemdata*/else{ //那就读到CACHE/*ReadalldatafromtheNVRAMfile*/status=ReadRecordInt(NVRAM_EF_CACHE_BYTE_LID,1,byte_data,NVRAM_CACHE_SIZE,&error,fileName,lineNumber);memcpy(&byte_data[nDataItemId*nDataType],pBuffer,nDataType); //读好了,就写吧/*writeintoNVRAMmodule,ifnotwaitforfalshingdirectly*/if(!byteDataWriteFlashFlag){ //关键还是WriteRecordIntstatus=WriteRecordInt(NVRAM_EF_CACHE_BYTE_LID,1,byte_data,NVRAM_CACHE_SIZE,