本文主要对android4.4 RIL的telephony与modem的命令交互流程进行分析,当然本文不是重点介绍telephony。
telephony涉及具体业务逻辑内容比较多,包括sim、dail、sms、network等等,以后会针对这些内容学习分析。
RIL在Android体系中的位置:

(A) 应用层发起访问modem的请求
(B) RILD进程
(A) 应用层发起访问modem的请求
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java中的类RIL,提供了一系
列的接口给上层应用调用,以访问modem。当然这些接口并不是直接给APP使用,而是由framework中sim、dail、
sms、network等相关服务调用。
如: 以查询SIM卡状态getIccCardStatus()为例,该API为UiccController模块所调用:
完整的SIM卡请求log:
10-11 12:21:43.630 D/RILJ ( 1833): [3653]> GET_SIM_STATUS
10-11 12:21:43.630 D/RILC ( 1286): [0005]> GET_SIM_STATUS
10-11 12:21:43.630 D/RILC ( 1286): onRequest: GET_SIM_STATUS
10-11 12:21:43.630 D/ATC ( 1286): AT> AT+CPIN?
10-11 12:21:43.640 D/ATC ( 1286): AT< +CPIN: READY
10-11 12:21:43.640 D/ATC ( 1286): AT< OK
10-11 12:21:43.640 D/RILC ( 1286): [0005]< GET_SIM_STATUS {[app_type=1,app_state=5,perso_substate=2,aid_ptr=(null),app_label_ptr=(null),pin1_replaced=0,pin1=0,pin2=0],}
10-11 12:21:43.640 D/RILJ ( 1833): [3653]< GET_SIM_STATUS IccCardState {CARDSTATE_PRESENT,PINSTATE_UNKNOWN,num_apps=1,gsm_id=0{APPTYPE_SIM,APPSTATE_READY},cdma_id=8,ims_id=8}
发起请求:
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
- @Override
- public void
- getIccCardStatus(Message result) {
- //Note: This RIL request has not been renamed to ICC,
- // but this request is also valid for SIM and RUIM
- RILRequest rr = RILRequest.obtain(RIL_REQUEST_GET_SIM_STATUS, result); /* 获取一个RILRequest */
-
- if (RILJ_LOGD) riljLog(rr.serialString() + "> " + requestToString(rr.mRequest)); /* 参考log:[3653]> GET_SIM_STATUS */
-
- send(rr); /* 发送请求 */
- }
RILRequest.obtain是从内存池获取一个RILRequest实例,并初始化:
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
- class RILRequest {
- static final String LOG_TAG = "RilRequest";
-
- ... ...
-
- static RILRequest obtain(int request, Message result) {
- RILRequest rr = null;
-
- synchronized(sPoolSync) { /* 从内存池中取出一个RILRequest对象*/
- if (sPool != null) {
- rr = sPool;
- sPool = rr.mNext;
- rr.mNext = null;
- sPoolSize--;
- }
- }
-
- if (rr == null) { /* 如果内存池中没有,则实例化一个 */
- rr = new RILRequest();
- }
-
- rr.mSerial = sNextSerial.getAndIncrement(); /* 获取串号,并且+1 */
-
- rr.mRequest = request; /* 对应RIL_REQUEST_*请求 */
- rr.mResult = result;
- rr.mParcel = Parcel.obtain(); /* 初始化一个Parcel,用于封包以发送给底层RILD */
-
- if (result != null && result.getTarget() == null) {
- throw new NullPointerException("Message target must not be null");
- }
-
- // first elements in any RIL Parcel
- rr.mParcel.writeInt(request); /* 每个RIL Parcel最开始也最基本的两个元素 */
- rr.mParcel.writeInt(rr.mSerial);
- return rr; /* 返回这个从内存池中获取的实例 */
- }
-
- ... ...
-
- String
- serialString() {
- //Cheesy way to do %04d
- StringBuilder sb = new StringBuilder(8); /* 创建一个StringBuilder实例用于操作字符串 */
- String sn;
- long adjustedSerial = (((long)mSerial) - Integer.MIN_VALUE)%10000;
- sn = Long.toString(adjustedSerial); /* 把数值转换成字符串 */
-
- //sb.append("J[");
- sb.append('[');
- for (int i = 0, s = sn.length() ; i < 4 - s; i++) {
- sb.append('0');
- }
- sb.append(sn);
- sb.append(']');
- return sb.toString(); /* 转换出来的字符串格式: [xxxx] */
- }
-
- ... ...
- }
send(rr)发送请求到服务端:
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
- private void
- send(RILRequest rr) {
- Message msg;
-
- ... ...
-
- msg = mSender.obtainMessage(EVENT_SEND, rr); /* 发送EVENT_SEND时间,时间参数为RILRequest */
-
- acquireWakeLock(); /* 获取wakelock,禁止进入休眠 */
-
- msg.sendToTarget(); /* message从handler类获取,从而可以直接向该handler对象发送消息。target就是创建message的handler */
- }
实际上telephony无法直接与modem通讯,由于每个厂商的modem都不一样,modem存在于系统中的方式
也不一样,如:有的CPU芯片厂商的modem是以一个CP核的方式集成在基带上(高通、展讯等),有的CPU芯
片(Exynos 4412等)需要通过串口/USB外接modem模块,如:BC72 LTE模块等。
send(rr)向RILD发送请求,这里涉及一个进程间通信问题,而且Java侧与C++侧的进程通讯,当然这里并没
有用Android开发的朋友都熟悉的Bind,而是socket。
telephony/Java侧RIL命令交互的处理,暂且称为RILJ。
RILJ作为socket的客户端,RILD(rild进程)作为服务端,后面会分析rild进程。
socket客户端的创建:
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
- public RIL(Context context, int preferredNetworkType, int cdmaSubscription) {
- ... ...
-
- mSenderThread = new HandlerThread("RILSender"); /* 创建RILSender线程 */
- mSenderThread.start();
-
- Looper looper = mSenderThread.getLooper();
- mSender = new RILSender(looper);
-
- ConnectivityManager cm = (ConnectivityManager)context.getSystemService(
- Context.CONNECTIVITY_SERVICE);
- if (cm.isNetworkSupported(ConnectivityManager.TYPE_MOBILE) == false) {
- riljLog("Not starting RILReceiver: wifi-only");
- } else {
- riljLog("Starting RILReceiver");
- mReceiver = new RILReceiver();
- mReceiverThread = new Thread(mReceiver, "RILReceiver"); /* 创建RILReceiver线程 */
- mReceiverThread.start();
-
- ... ...
- }
-
- ... ...
- }
-
- class RILReceiver implements Runnable {
- byte[] buffer;
-
- RILReceiver() { /* 构造时,分配一个数组 */
- buffer = new byte[RIL_MAX_COMMAND_BYTES];
- }
-
- @Override
- public void
- run() { /* 循环读取从RILD返回或主动上报的数据 */
- int retryCount = 0;
-
- try {for (;;) {
- LocalSocket s = null;
- LocalSocketAddress l;
-
- try {
- s = new LocalSocket(); /* 创建一个socket客户端 */
- l = new LocalSocketAddress(SOCKET_NAME_RIL,
- LocalSocketAddress.Namespace.RESERVED);
- s.connect(l); /* 连接服务器 */
- }
-
- ... ...
- }
-
- ... ...
-
- try {
- InputStream is = mSocket.getInputStream(); /* 循环读取socket的数据 */
-
- for (;;) {
- Parcel p;
- length = readRilMessage(is, buffer); /* 解析socket数据 */
-
- if (length < 0) {
- // End-of-stream reached
- break;
- }
- p = Parcel.obtain(); /* 获取一个Parcel */
- p.unmarshall(buffer, 0, length); /* 读取出来的就是之前序列化的byte数组,所以要进行一个反序列化操作 */
- p.setDataPosition(0); /* 从buffer转换到Parcel之后,需要将指针手动指向到最初的位置 */
-
- //Rlog.v(RILJ_LOG_TAG, "Read packet: " + length + " bytes");
- processResponse(p);
- p.recycle(); /* 数据处理完后,需要回收Parcel的内存 */
- }
- }
-
- ... ...
- }
RILReceiver线程创建socket客户端,连接服务端,然后进入等待服务端的processResponse消息处理循环,RILJ
接收到RILD回复的response返回RIL请求的发起者,以getIccCardStatus(Message result)为例,processResponse(p)
会把DRILD的response返回给UiccController
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
- private static int readRilMessage(InputStream is, byte[] buffer)
- throws IOException {
- int countRead;
- int offset;
- int remaining;
- int messageLength;
- // First, read in the length of the message
- offset = 0;
- remaining = 4;
- do {
- countRead = is.read(buffer, offset, remaining); /* 读出消息的4字节长度 */
-
- if (countRead < 0 ) {
- Rlog.e(RILJ_LOG_TAG, "Hit EOS reading message length");
- return -1;
- }
- offset += countRead;
- remaining -= countRead;
- } while (remaining > 0);
- messageLength = ((buffer[0] & 0xff) << 24) /* 获取长度 */
- | ((buffer[1] & 0xff) << 16)
- | ((buffer[2] & 0xff) << 8)
- | (buffer[3] & 0xff);
- // Then, re-use the buffer and read in the message itself
- offset = 0;
- remaining = messageLength;
- do {
- countRead = is.read(buffer, offset, remaining); /* 读取剩余的数据 */
-
- if (countRead < 0 ) {
- Rlog.e(RILJ_LOG_TAG, "Hit EOS reading message. messageLength=" + messageLength
- + " remaining=" + remaining);
- return -1;
- }
- offset += countRead;
- remaining -= countRead;
- } while (remaining > 0);
- return messageLength;
- }
- private void
- processResponse (Parcel p) {
- int type;
- type = p.readInt(); /* 从RILD返回的数据第一个字节,表示请求的返回类型:RESPONSE_UNSOLICITED/RESPONSE_SOLICITED */
-
- if (type == RESPONSE_UNSOLICITED) {
- processUnsolicited (p); /* 主动上报 */
- } else if (type == RESPONSE_SOLICITED) {
- RILRequest rr = processSolicited (p); /* 普通请求对应的同步上报 */
- if (rr != null) {
- rr.release(); /* 释放对应的RILRequest内存和wakelock */
- decrementWakeLock();
- }
- }
- }
RILD的response一般有两种,一种是RILJ普通请求,RILD对RILJ请求的response (RESPONSE_SOLICITED),另一种是RILD主动上报的
response (RESPONSE_UNSOLICITED), processResponse (Parcel p)分别对这两种情况的response进行处理。
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
- private RILRequest
- processSolicited (Parcel p) {
- int serial, error;
- boolean found = false;
- serial = p.readInt(); /* 串号,也就是token */
- error = p.readInt(); /* 错误码 */
- RILRequest rr;
- rr = findAndRemoveRequestFromList(serial); /* 根据taken取出对应的RILRequest */
- ... ...
- */
- case RIL_REQUEST_GET_SIM_STATUS: ret = responseIccCardStatus(p); break;
- ... ...
-
- if (rr.mResult != null) {
- AsyncResult.forMessage(rr.mResult, ret, null); /* 把rr.mResult存到AsyncResult.userObj,并把rr.mResult.obj转换为AsyncResult */
- rr.mResult.sendToTarget(); /* msg发送到对应的target(Handler) */
- }
-
- ... ...
- }
-
- private Object
- responseIccCardStatus(Parcel p) {
- IccCardApplicationStatus appStatus;
-
- ... ...
-
- appStatus = new IccCardApplicationStatus();
-
- ... ...
- return cardStatus;
- }
回到刚才send(rr),send(rr)并不是直接发送到socket服务端RILD,而是通过一个Message发送到RILSender线程,
在handleMessage中,把请求发到socket服务端RILD。
frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
- class RILSender extends Handler implements Runnable { /* 继承Handler,实现Runnable */
- public RILSender(Looper looper) {
- super(looper);
- }
-
- ... ...
-
- //***** Handler implementation
- @Override public void
- handleMessage(Message msg) { /* 继承Handler的handleMessage */
- RILRequest rr = (RILRequest)(msg.obj); /* Maessage中携带的RILRequest对象 */
- RILRequest req = null;
-
- switch (msg.what) {
- case EVENT_SEND: /* 发送RIL请求事件 */
- try {
- LocalSocket s;
-
- s = mSocket; /* RILReceiver中创建的用于与RILD通讯的socket */
-
- ... ...
-
- synchronized (mRequestList) { /* 多线程保护操作mRequestList */
- mRequestList.append(rr.mSerial, rr); /* 把接受到的RILRequest和对应的串号,存到mRequestList数据 */
- }
- byte[] data;
- data = rr.mParcel.marshall(); /* 把Parcel中的数据转换为byte数据 */
- rr.mParcel.recycle(); /* Parcel的内存回收 */
- rr.mParcel = null;
- ... ...
- // parcel length in big endian
- dataLength[0] = dataLength[1] = 0; /* RIL请求包的大小为4个字节 */
- dataLength[2] = (byte)((data.length >> 8) & 0xff);
- dataLength[3] = (byte)((data.length) & 0xff);
- //Rlog.v(RILJ_LOG_TAG, "writing packet: " + data.length + " bytes");
- s.getOutputStream().write(dataLength); /* 把包大小和包数据发送出去 */
- s.getOutputStream().write(data);
- } catch (IOException ex) {
- Rlog.e(RILJ_LOG_TAG, "IOException", ex);
- req = findAndRemoveRequestFromList(rr.mSerial); /* 如果出现异常,则把串号对应的RILRequest从mRequestList中删除 */
- // make sure this request has not already been handled,
- // eg, if RILReceiver cleared the list.
- if (req != null) {
- rr.onError(RADIO_NOT_AVAILABLE, null);
- rr.release();
- decrementWakeLock();
- }
- }
-
- ... ...
- }
- }
- }
(B) RILD进程
RILD作为一个独立的进程,telephony与modem之间的通讯通道。抽象出一些接口以适配不同的modem厂商,无需关心具体的
硬件操作,或者以哪种形式存存在于系统(modem作为CP集成于CPU或CPU通过串口/USB连接,如: BC72 LTE模块)。因为这些接口
由厂商去实现具体的硬件操作细节,这些接口都在libreference-ril中,在Android中使用BC72 LTE模块,只要移植
libreference-ril就行。
1. RILD的启动
RILD有init进程直接启动,启动后就监听RILJ客户端,等待RILJ连接请求。
device/samsung/smdk4x12/conf/init.smdk4x12.rc
- service ril-daemon /system/bin/rild -l /system/lib/libreference-ril.so
- class main
- socket rild stream 660 root radio
- socket rild-debug stream 660 radio system
- user root
hardware/ril/rild/rild.c为RILD进程入口:
hardware/ril/rild/rild.c
- int main(int argc, char **argv)
- {
- ... ...
-
- dlHandle = dlopen(rilLibPath, RTLD_NOW); /* 打开/system/lib/libreference-ril.so */
-
- if (dlHandle == NULL) {
- RLOGE("dlopen failed: %s", dlerror());
- exit(-1);
- }
- RIL_startEventLoop(); /* 创建eventLoop线程, 在ril_event_loop()中监听多路IO的事件,如主动唤醒事件(pipe)、RILJ的请求等 */
-
- /* 获取/system/lib/libreference-ril.so中RIL_Init函数指针 */
- rilInit = (const RIL_RadioFunctions *(*)(const struct RIL_Env *, int, char **))dlsym(dlHandle, "RIL_Init");
- if (rilInit == NULL) {
- RLOGE("RIL_Init not defined or exported in %s\n", rilLibPath);
- exit(-1);
- }
- if (hasLibArgs) {
- rilArgv = argv + i - 1;
- argc = argc -i + 1;
- } else {
- static char * newArgv[MAX_LIB_ARGS];
- static char args[PROPERTY_VALUE_MAX];
- rilArgv = newArgv;
- property_get(LIB_ARGS_PROPERTY, args, "");
- argc = make_argv(args, rilArgv);
- }
- // Make sure there's a reasonable argv[0]
- rilArgv[0] = argv[0];
- funcs = rilInit(&s_rilEnv, argc, rilArgv); /* 初始化Vender RIL */
- RIL_register(funcs); /* 注册RIL */
-
- ... ...
- }
hardware/ril/libril/ril.cpp
- extern "C" void
- RIL_startEventLoop(void) {
-
- ... ...
-
- ret = pthread_create(&s_tid_dispatch, &attr, eventLoop, NULL); /* 创建eventLoop线程 */
- ... ...
- }
-
- static void *
- eventLoop(void *param) {
- int ret;
- int filedes[2];
- ril_event_init(); /* 初始化事件链表,timer_list,pending_list, watch_table */
- pthread_mutex_lock(&s_startupMutex);
- s_started = 1;
- pthread_cond_broadcast(&s_startupCond);
- pthread_mutex_unlock(&s_startupMutex);
- ret = pipe(filedes); /* 创建一个pipe,用于每次添加一个新事件时,唤醒selet()返回,更新fd_set使select监听新的事件 */
-
- if (ret < 0) {
- RLOGE("Error in pipe() errno:%d", errno);
- return NULL;
- }
- s_fdWakeupRead = filedes[0]; /* filedes[0]用于读pipe, filedes[1]用于写pipe */
- s_fdWakeupWrite = filedes[1];
- fcntl(s_fdWakeupRead, F_SETFL, O_NONBLOCK); /* 以非阻塞的方式读pipe */
- ril_event_set (&s_wakeupfd_event, s_fdWakeupRead, true, /* 读pipe描述符绑定到s_wakeupfd_event事件,指定回调processWakeupCallback */
- processWakeupCallback, NULL);
- rilEventAddWakeup (&s_wakeupfd_event); /* 添加s_wakeupfd_event事件到watch_table,更新readFds集合,使select监听该事件,并触发该事件 */
-
- // Only returns on error
- ril_event_loop(); /* 进入多路IO事件监听循环 */
- RLOGE ("error in event_loop_base errno:%d", errno);
- // kill self to restart on error
- kill(0, SIGKILL);
- return NULL;
- }
main函数主要启动eventLoop线程,在ril_event_loop()中监听多路IO的事件,如主动唤醒事件(pipe)、RILJ的请求等,
注册vendor RIL接口(libreference-ril)
注意这里pipe的主要作用是唤醒select返回,因为每次动态的添加一个事件,都要更新readFds集合,方便select监听
集合中新的IO。
rilEventAddWakeup()添加新事件后,都会触发select返回
hardware/ril/libril/ril.cpp
- static void rilEventAddWakeup(struct ril_event *ev) {
- ril_event_add(ev); /* 添加事件 */
- triggerEvLoop(); /* 触发事件, 每添加一个事件,都通过写pipe唤醒select,以更新多路IO集合,使能够监听该事件 */
- }
hardware/ril/libril/ril_event.cpp
- void ril_event_add(struct ril_event * ev)
- {
- dlog("~~~~ +ril_event_add ~~~~");
- MUTEX_ACQUIRE();
- for (int i = 0; i < MAX_FD_EVENTS; i++) {
- if (watch_table[i] == NULL) {
- watch_table[i] = ev; /* 将新事件添加到watch_table */
- ev->index = i;
- dlog("~~~~ added at %d ~~~~", i);
- dump_event(ev);
- FD_SET(ev->fd, &readFds); /* 更新readFds集合 */
- if (ev->fd >= nfds) nfds = ev->fd+1; /* 更新nfds */
- dlog("~~~~ nfds = %d ~~~~", nfds);
- break;
- }
- }
- MUTEX_RELEASE();
- dlog("~~~~ -ril_event_add ~~~~");
- }
hardware/ril/libril/ril.cpp
- static void triggerEvLoop() {
- int ret;
- if (!pthread_equal(pthread_self(), s_tid_dispatch)) {
- /* trigger event loop to wakeup. No reason to do this,
- * if we're in the event loop thread */
- do {
- ret = write (s_fdWakeupWrite, " ", 1); /* 向pipe写入一个" ",以唤醒select */
- } while (ret < 0 && errno == EINTR);
- }
- }
在ril_event_loop()接收到事件或socket客户端RILJ发过来的请求后,firePending()根据事件请求,调用相应的处理函数
hardware/ril/libril/ril_event.cpp
- void ril_event_loop()
- {
- int n;
- fd_set rfds;
- struct timeval tv;
- struct timeval * ptv;
- for (;;) {
- // make local copy of read fd_set
- memcpy(&rfds, &readFds, sizeof(fd_set));
- if (-1 == calcNextTimeout(&tv)) { /* 计算timer_list链表中每个事件对应的超时时间 */
- // no pending timers; block indefinitely
- dlog("~~~~ no timers; blocking indefinitely ~~~~");
- ptv = NULL;
- } else {
- dlog("~~~~ blocking for %ds + %dus ~~~~", (int)tv.tv_sec, (int)tv.tv_usec);
- ptv = &tv;
- }
- printReadies(&rfds);
- n = select(nfds, &rfds, NULL, NULL, ptv); /* 等待readFds集合中的事件唤醒 */
- printReadies(&rfds);
- dlog("~~~~ %d events fired ~~~~", n);
- if (n < 0) {
- if (errno == EINTR) continue;
- RLOGE("ril_event: select error (%d)", errno);
- // bail?
- return;
- }
- // Check for timeouts
- processTimeouts(); /* 检查timer_list链表中是否有事件已经超时 */
- // Check for read-ready
- processReadReadies(&rfds, n); /* 从watch_table中取出监听到的事件, 并添加到pending_list链表 */
- // Fire away
- firePending(); /* 从pending_list依次取出事件,并执行该事件的回调 */
- }
- }
-
- static void processTimeouts()
- {
- dlog("~~~~ +processTimeouts ~~~~");
- MUTEX_ACQUIRE();
- struct timeval now;
- struct ril_event * tev = timer_list.next;
- struct ril_event * next;
- getNow(&now);
- // walk list, see if now >= ev->timeout for any events
- /* 检查timer_list链表中是否有事件已经超时 */
- dlog("~~~~ Looking for timers <= %ds + %dus ~~~~", (int)now.tv_sec, (int)now.tv_usec);
- while ((tev != &timer_list) && (timercmp(&now, &tev->timeout, >))) {
- // Timer expired
- dlog("~~~~ firing timer ~~~~");
- next = tev->next;
- removeFromList(tev); /* 将该超时移出链表 */
- addToList(tev, &pending_list); /* 并且将该超时添加到pending链表 */
- tev = next; /* 指针指向下一个超时 */
- }
- MUTEX_RELEASE();
- dlog("~~~~ -processTimeouts ~~~~");
- }
-
- static void processReadReadies(fd_set * rfds, int n)
- {
- dlog("~~~~ +processReadReadies (%d) ~~~~", n);
- MUTEX_ACQUIRE();
- for (int i = 0; (i < MAX_FD_EVENTS) && (n > 0); i++) {
- struct ril_event * rev = watch_table[i];
- if (rev != NULL && FD_ISSET(rev->fd, rfds)) { /* 从watch_table中取出监听到的事件 */
- addToList(rev, &pending_list); /* 并把该事件加入pending_list链表 */
- if (rev->persist == false) { /* 如果该事件不需要处理,则移出removeWatch */
- removeWatch(rev, i);
- }
- n--;
- }
- }
- MUTEX_RELEASE();
- dlog("~~~~ -processReadReadies (%d) ~~~~", n);
- }
-
- static void firePending()
- {
- dlog("~~~~ +firePending ~~~~");
- struct ril_event * ev = pending_list.next;
- while (ev != &pending_list) { /* 从pending_list依次取出事件 */
- struct ril_event * next = ev->next;
- removeFromList(ev);
- ev->func(ev->fd, 0, ev->param); /* 并执行该事件的回调 */
- ev = next;
- }
- dlog("~~~~ -firePending ~~~~");
- }
上面分析了RIL_startEventLoop()的事件流程,简单总结就是根据事件调用该事件的处理函数。
到这里还没说到怎样创建socket服务端的,回到mian(),funcs = rilInit(&s_rilEnv, argc, rilArgv);
初始化了libreference-ril,RIL_register(funcs);注册了厂商须实现的相关接口,创建socket服务端的,
并监听客户端连接,一旦连接,则开始等待读取客户端发过来的请求。
hardware/ril/libril/ril.cpp
- extern "C" void
- RIL_register (const RIL_RadioFunctions *callbacks) {
-
- ... ...
-
- s_fdListen = android_get_control_socket(SOCKET_NAME_RIL); /* 创建socket服务端,用于与RILJ通信 */
- if (s_fdListen < 0) {
- RLOGE("Failed to get socket '" SOCKET_NAME_RIL "'");
- exit(-1);
- }
- ret = listen(s_fdListen, 4); /* 监听RILJ */
-
- if (ret < 0) {
- RLOGE("Failed to listen on control socket '%d': %s",
- s_fdListen, strerror(errno));
- exit(-1);
- }
- /* note: non-persistent so we can accept only one connection at a time */
- ril_event_set (&s_listen_event, s_fdListen, false, /* 设置一个监听事件s_listen_event,一旦与RILJ建立连 */
- listenCallback, NULL); /* 则进入listenCallback,等待读取RILJ发送数据 */
- rilEventAddWakeup (&s_listen_event); /* 添加s_listen_event到watch_table, 唤醒select */
-
- ... ...
- }
-
- static void listenCallback (int fd, short flags, void *param) {
- ... ...
-
- s_fdCommand = accept(s_fdListen, (sockaddr *) &peeraddr, &socklen); /* 接受RILJ客户端的连接 */
- ... ...
-
- err = getsockopt(s_fdCommand, SOL_SOCKET, SO_PEERCRED, &creds, &szCreds);
-
- ret = fcntl(s_fdCommand, F_SETFL, O_NONBLOCK); /* 非阻塞方式读写socket */
-
- if (ret < 0) {
- RLOGE ("Error setting O_NONBLOCK errno:%d", errno);
- }
- RLOGI("libril: new connection");
- p_rs = record_stream_new(s_fdCommand, MAX_COMMAND_BYTES); /* 创建一个stream用于缓存读socket的数据 */
- ril_event_set (&s_commands_event, s_fdCommand, 1, /* 设置s_commands_event,processCommandsCallback循环读取socket的数据 */
- processCommandsCallback, p_rs);
- rilEventAddWakeup (&s_commands_event); /* 添加s_commands_event事件,唤醒select */
- onNewCommandConnect(); /* 通知RILJ已建立连接 */
- }
- static void processCommandsCallback(int fd, short flags, void *param) {
-
- ... ...
-
- for (;;) {
- /* loop until EAGAIN/EINTR, end of stream, or other error */
- ret = record_stream_get_next(p_rs, &p_record, &recordlen); /* 循环从数据流中读取socket数据 */
-
- if (ret == 0 && p_record == NULL) {
- /* end-of-stream */
- break;
- } else if (ret < 0) {
- break;
- } else if (ret == 0) { /* && p_record != NULL */
- processCommandBuffer(p_record, recordlen); /* 对接受到的数据进行组包,下发给vender ril,即libreference-ril.so */
- }
- }
- }
processCommandBuffer(p_record, recordlen)对接收到的数据进行组包,下发给vender ril,即libreference-ril.so,
然后就脱离了RILD的控制了,libreference-ril.so主要是厂商对RILD控制modem接口的实现。
hardware/ril/libril/ril.cpp
- static int
- processCommandBuffer(void *buffer, size_t buflen) {
- ... ...
- p.setData((uint8_t *) buffer, buflen); /* 把接受到的数据填装到parcel */
-
- // status checked at end
- status = p.readInt32(&request); /* 解析request */
- status = p.readInt32 (&token); /* 解析token,RILJ中的serial */
- ... ...
-
- pRI = (RequestInfo *)calloc(1, sizeof(RequestInfo)); /* 分配一个RequestInfo,用于发送请求给vendor ril */
- pRI->token = token; /* 设置token */
- pRI->pCI = &(s_commands[request]); /* 设置请求 */
- ret = pthread_mutex_lock(&s_pendingRequestsMutex);
- assert (ret == 0);
- pRI->p_next = s_pendingRequests; /* 添加到s_pendingRequests请求链表中 */
- s_pendingRequests = pRI;
- ret = pthread_mutex_unlock(&s_pendingRequestsMutex);
- assert (ret == 0);
- /* sLastDispatchedToken = token; */
- pRI->pCI->dispatchFunction(p, pRI); /* 执行事件回调,到这里开始进入vender ril了 */
-
- return 0;
- }
我们仍然以获取SIM卡状态为例,pRI->pCI->dispatchFunction(p, pRI)对应调用了dispatchVoid()
hardware/ril/libril/ril.cpp
- static void
- dispatchVoid (Parcel& p, RequestInfo *pRI) {
- clearPrintBuf;
- printRequest(pRI->token, pRI->pCI->requestNumber);
- s_callbacks.onRequest(pRI->pCI->requestNumber, NULL, 0, pRI);
- }
s_callbacks.onRequest(pRI->pCI->requestNumber, NULL, 0, pRI); 调用的就是libreference-ril.c中的onRequest()函数。
以上分析了RILD对RILJ下发的请求处理流程,下面接着分析RILD返回response给RILJ的流程。分两种情况,一种对请求的响应,
另一种是主动上报。
libreference-ril对请求处理完毕后,调用RIL_onRequestComplete回复RILJ该请求的处理结果。
hardware/ril/libril/ril.cpp
- RIL_onRequestComplete(RIL_Token t, RIL_Errno e, void *response, size_t responselen) {
-
- ... ...
- p.writeInt32 (RESPONSE_SOLICITED);
- p.writeInt32 (pRI->token);
- errorOffset = p.dataPosition();
-
- p.writeInt32 (e);
-
- if (response != NULL) {
- // there is a response payload, no matter success or not.
- ret = pRI->pCI->responseFunction(p, response, responselen);
-
- ... ...
- }
-
- ... ...
-
- sendResponse(p);
-
- ... ...
- }
-
- static int
- sendResponse (Parcel &p) {
- printResponse;
- return sendResponseRaw(p.data(), p.dataSize());
- }
- static int
- sendResponseRaw (const void *data, size_t dataSize) {
- ... ...
- ret = blockingWrite(fd, (void *)&header, sizeof(header)); /* 先写4字节数据长度 */
-
- if (ret < 0) {
- pthread_mutex_unlock(&s_writeMutex);
- return ret;
- }
- ret = blockingWrite(fd, data, dataSize); /* 再写数据 */
- ... ...
- }
最终是通过sendResponseRaw()直接通过写socket回复RILJ。对于主动上报的处理是类似的,也是通过sendResponseRaw()
上报给RILJ。可以参考RIL_onUnsolicitedResponse()函数。
到此,RILJ与RILD之间的通信流程已经分析完,后续分析libreference-ril。libreference-ril中先关接口的实现方式,每个modem厂商都不一样。
BC72是通过串口/USB发送AT的方式控制,实现通话、短信、上网等功能。
谢谢!