Android 8.0 RIL源码分析（二）

非URC消息处理
之前分析到在at_send_command_full_nolock调用后会先发送消息给modem,然后阻塞当前线程等待modem返回消息。

因此也是在readerLoop的消息处理中去唤醒阻塞的线程，而且应该把数据直接返回给阻塞的线程，如之前ndroid 8.0 RIL框架分析，非URC消息会调用processLine方法。

1.这里跟进到processLine方法

 static void processLine(const char *line)
{
    pthread_mutex_lock(&s_commandmutex);

    if (sp_response == NULL) {
        /* no command pending */
        handleUnsolicited(line);
    } else if (isFinalResponseSuccess(line)) {
        sp_response->success = 1;
        //将消息发回给eventLoop
        handleFinalResponse(line);
    } else if (isFinalResponseError(line)) {
        sp_response->success = 0;
        handleFinalResponse(line);
    } else if (s_smsPDU != NULL && 0 == strcmp(line, "> ")) {
        // See eg. TS 27.005 4.3
        // Commands like AT+CMGS have a "> " prompt
        writeCtrlZ(s_smsPDU);
        s_smsPDU = NULL;
    } else switch (s_type) {
        case NO_RESULT:

            handleUnsolicited(line);
            break;
        case NUMERIC:
            if (sp_response->p_intermediates == NULL
                && isdigit(line[0])
            ) {
                addIntermediate(line);
            } else {
                /* either we already have an intermediate response or
                   the line doesn't begin with a digit */
                handleUnsolicited(line);
            }
            break;
        case SINGLELINE:
            if (sp_response->p_intermediates == NULL
                && strStartsWith (line, s_responsePrefix)
            ) {
                addIntermediate(line);
            } else {
                /* we already have an intermediate response */
                handleUnsolicited(line);
            }
            break;
        case MULTILINE:
            if (strStartsWith (line, s_responsePrefix)) {
                addIntermediate(line);
            } else {
                handleUnsolicited(line);
            }
        break;

        default: /* this should never be reached */
            RLOGE("Unsupported AT command type %d\n", s_type);
            handleUnsolicited(line);
        break;
    }

    pthread_mutex_unlock(&s_commandmutex);
}

2.继续跟进handleFinalResponse

/** assumes s_commandmutex is held */
static void handleFinalResponse(const char *line)
{
    //把回应消息返回给RIL
    sp_response->finalResponse = strdup(line);
    //唤醒阻塞线程
    pthread_cond_signal(&s_commandcond);
}

3.回到at_send_command_full_nolock

    if (pp_outResponse == NULL) {
        at_response_free(sp_response);
    } else {
        /* line reader stores intermediate responses in reverse order */
        reverseIntermediates(sp_response);
        //返回的数据
        *pp_outResponse = sp_response;
    }

4.回到最开始的 requestDial,在获取到返回数据后会调用RIL_onRequestComplete

static void requestDial(void *data, size_t datalen __unused, RIL_Token t)
{
    RIL_Dial *p_dial;
    char *cmd;
    const char *clir;
    int ret;

    p_dial = (RIL_Dial *)data;

    switch (p_dial->clir) {
        case 1: clir = "I"; break;  /*invocation*/
        case 2: clir = "i"; break;  /*suppression*/
        default:
        case 0: clir = ""; break;   /*subscription default*/
    }

    asprintf(&cmd, "ATD%s%s;", p_dial->address, clir);

    ret = at_send_command(cmd, NULL);

    free(cmd);

    /* success or failure is ignored by the upper layer here.
       it will call GET_CURRENT_CALLS and determine success that way */
    RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
}

5.这就回到ril.c的onRequestComplete中

extern "C" void
RIL_onRequestComplete(RIL_Token t, RIL_Errno e, void *response, size_t responselen) {
    RequestInfo *pRI;
    int ret;
    RIL_SOCKET_ID socket_id = RIL_SOCKET_1;

    pRI = (RequestInfo *)t;

    if (!checkAndDequeueRequestInfoIfAck(pRI, false)) {
        RLOGE ("RIL_onRequestComplete: invalid RIL_Token");
        return;
    }

    socket_id = pRI->socket_id;
#if VDBG
    RLOGD("RequestComplete, %s", rilSocketIdToString(socket_id));
#endif

    if (pRI->local > 0) {
        // Locally issued command...void only!
        // response does not go back up the command socket
        RLOGD("C[locl]< %s", requestToString(pRI->pCI->requestNumber));

        free(pRI);
        return;
    }

    appendPrintBuf("[%04d]< %s",
        pRI->token, requestToString(pRI->pCI->requestNumber));

    if (pRI->cancelled == 0) {
        int responseType;
        if (s_callbacks.version >= 13 && pRI->wasAckSent == 1) {
            // If ack was already sent, then this call is an asynchronous response. So we need to
            // send id indicating that we expect an ack from RIL.java as we acquire wakelock here.
            responseType = RESPONSE_SOLICITED_ACK_EXP;
            grabPartialWakeLock();
        } else {
            responseType = RESPONSE_SOLICITED;
        }

        // there is a response payload, no matter success or not.
#if VDBG
        RLOGE ("Calling responseFunction() for token %d", pRI->token);
#endif

        pthread_rwlock_t *radioServiceRwlockPtr = radio::getRadioServiceRwlock((int) socket_id);
        int rwlockRet = pthread_rwlock_rdlock(radioServiceRwlockPtr);
        assert(rwlockRet == 0);

        //调用返回的响应方法
        ret = pRI->pCI->responseFunction((int) socket_id,
                responseType, pRI->token, e, response, responselen);

        rwlockRet = pthread_rwlock_unlock(radioServiceRwlockPtr);
        assert(rwlockRet == 0);
    }
    free(pRI);
}

5.跟进到RadioResponse

public class RadioResponse extends IRadioResponse.Stub {
    /**
     * @param responseInfo Response info struct containing response type, serial no. and error
     */
    public void dialResponse(RadioResponseInfo responseInfo) {
        responseVoid(responseInfo);
    }

6.继续跟进responseVoid

    public void responseVoid(RadioResponseInfo responseInfo) {
        //创建rilRequest反馈对象
        RILRequest rr = mRil.processResponse(responseInfo);

        if (rr != null) {
            Object ret = null;
            if (responseInfo.error == RadioError.NONE) {
            //modem处理成功
                sendMessageResponse(rr.mResult, ret);
            }
            mRil.processResponseDone(rr, responseInfo, ret);
        }
    }

7.将消息发送回请求的地方

    public static void sendMessageResponse(Message msg, Object ret) {
        if (msg != null) {
            AsyncResult.forMessage(msg, ret, null);
            msg.sendToTarget();
        }
    }

URC消息处理
1.之前分析过如果是底层主动上报的URC消息则是使用handleUnsolicited进行处理

static void handleUnsolicited(const char *line)
{
    if (s_unsolHandler != NULL) {
        s_unsolHandler(line, NULL);
    }
}

可以看到s_unsolHandler是个静态变量

static ATUnsolHandler s_unsolHandler;

查找s_unsolHandler的初始化

int at_open(int fd, ATUnsolHandler h)
{
    ...
    s_unsolHandler = h;
    ...
}

可以看到是在at_open的时候传入的handler,继续往上追溯mainLoop

static void *
mainLoop(void *param __unused)
{      
    ...
    ret = at_open(fd, onUnsolicited);
    ...
}

2.可以看到其实调用的是reference-ril.c中的onUnsolicited方法

/**
 * Called by atchannel when an unsolicited line appears
 * This is called on atchannel's reader thread. AT commands may
 * not be issued here
 */
static void onUnsolicited (const char *s, const char *sms_pdu)
{
    ...
    if (strStartsWith(s, "%CTZV:")) {
        /* TI specific -- NITZ time */
        char *response;

        line = p = strdup(s);
        at_tok_start(&p);

        err = at_tok_nextstr(&p, &response);

        if (err != 0) {
            RLOGE("invalid NITZ line %s\n", s);
        } else {
            RIL_onUnsolicitedResponse (
                RIL_UNSOL_NITZ_TIME_RECEIVED,
                response, strlen(response));
        }
        free(line);
    } 
    ...省略多个else if
}

可以看到其最后调用RIL_onUnsolicitedResponse进行处理

#define RIL_onRequestComplete(t, e, response, responselen) s_rilenv->OnRequestComplete(t,e, response, responselen)
#define RIL_onUnsolicitedResponse(a,b,c) s_rilenv->OnUnsolicitedResponse(a,b,c)

3.继续跟进RIL_onUnsolicitedResponse

extern "C"
void RIL_onUnsolicitedResponse(int unsolResponse, const void *data,
                                size_t datalen)
{
            ...
            ret = s_unsolResponses[unsolResponseIndex].responseFunction(
            (int) soc_id, responseType, 0, RIL_E_SUCCESS, const_cast(data),
            datalen);
            ...
}

查看UnsolResponseInfo结构

typedef struct {
    int requestNumber;
    int (*responseFunction) (int slotId, int responseType, int token,
            RIL_Errno e, void *response, size_t responselen);
    WakeType wakeType;
} UnsolResponseInfo;

查找UnsolResponseInfo 的初始化

static UnsolResponseInfo s_unsolResponses[] = {
#include "ril_unsol_commands.h"
};

可以看到这个头文件的定义和N上已经发生了改变

    {RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED, radio::callStateChangedInd, WAKE_PARTIAL},

4.跟进对应的callStateChangedInd响应方法

ril-service.cp  
int radio::callStateChangedInd(int slotId,
                               int indicationType, int token, RIL_Errno e, void *response,
                               size_t responseLen) {
    if (radioService[slotId] != NULL && radioService[slotId]->mRadioIndication != NULL) {
#if VDBG
        RLOGD("callStateChangedInd");
#endif
        Return<void> retStatus = radioService[slotId]->mRadioIndication->callStateChanged(
                convertIntToRadioIndicationType(indicationType));
        radioService[slotId]->checkReturnStatus(retStatus);
    } else {
        RLOGE("callStateChangedInd: radioService[%d]->mRadioIndication == NULL", slotId);
    }

    return 0;
}

5.可以看到其又通过HIDL调用到RILJ处的方法

frameworks\opt\telephony\src\java\com\android\internal\telephony\RadioIndication.java

    public void callStateChanged(int indicationType) {
        mRil.processIndication(indicationType);

        if (RIL.RILJ_LOGD) mRil.unsljLog(RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED);
        //继续通知消息
        mRil.mCallStateRegistrants.notifyRegistrants();
    }

RILJ到RILC的HIDL调用