Thursday, April 9, 2009

[android] trace radio interface layer (RIL) by two emulators

I study android from this week and my entry point is based on my related GSM network experiences. Yeah! Let's start it from code tracing: how to register to the network, how to receive/dial a phone call, how to send/receive a SMS message...etc...

A. Set up the working environment: my machine is ubuntu 8.10, kernel is 2.6.27-11-generic.

1. download Android SDK
unzip the file, and you will see theses two tools ( emulator & adb) we need.

2. download Android source code
just follow the steps, and type 'make', then i get it all done. (yes, i'm a lucky person!)

B. Let's have fun with multiple emulator:
1. prepare two terminals:

terminal A: $emulator -skin HVGA-P -data lib/images/userdata.img -debug modem,radio -scale 0.5
terminal B: $emulator -skin HVGA-L -data lib/images/userdata2.img -debug modem,radio -scale 0.5

2. it would come out with two emulators: (I changed one of them to use iPhone skin!)

3. When both of them camp to the 'Android' network, use Dialer in emulator-5554 and dial '5556', then it would display an incoming call in emulator-5556. (5554 and 5556 are their port number)

4. Answer the incoming call in emulator-5556 and then hang up in emulator-5554. (You will receive different events if you hang up in emulator-5556.)

5. DONE! Let's get the log date from both of them.

$adb -s emulator-5554 logcat -b radio -d > radio.5554
$adb -s emulator-5556 logcat -b radio -d > radio.5556
$adb -s emulator-5554 logcat *:D -d > debugall.5554
$adb -s emulator-5556 logcat *:D -d > debugall.5556

C. Check the RIL process by these photos

D. How to dial out a call in Android? I traced the radio log and make sure the whole procedure and the source code.
DIAL out a phone call: (MO call)

from top UI to bottom,
[App] Phone Application ---> [App Framework] Telephony Manager (GSM) --->
[App Framework] Telephony Manager (RIL) ---> [Libraries] Telephony Manager
---> [Libraries] rild ---> [Libraries] ---> [Kernel Driver] Baseband

RIL: /hardware/ril/reference-ril/refereince-ril.c
AT: /hardware/ril/reference-ril/atchannel.c
RILD: /hardware/ril/rild/rild.c
RILC: /hardware/ril/libril/ril.cpp
RILJ: /frameworks/base/telephony/java/com/android/internal/telephony/gsm/
GSM: /frameworks/base/telephony/java/com/android/internal/telephony/gsm/

D/RILJ ( 85): [0053]> DIAL
D/RIL ( 22): onRequest: DIAL
D/AT ( 22): AT> ATD5556;
D/AT ( 22): AT< OK

D/GSM ( 85): [GSMConn] update: parent=DIALING, hasNewParent=false, wasConnectingInOrOut=true,
wasHolding=false, isConnectingInOrOut=true, changed=false
D/AT ( 22): AT< RING
D/RILJ ( 85): [0059]> SET_MUTE false
D/RIL ( 22): onRequest: SET_MUTE
D/RILJ ( 85): [0059]< SET_MUTE error:
D/RIL ( 22): onRequest: GET_CURRENT_CALLS
D/AT ( 22): AT> AT+CLCC
D/AT ( 22): AT< +CLCC: 1,0,3,0,0,"5556",129
D/AT ( 22): AT< OK

D/RILJ ( 85): [0124]< GET_CURRENT_CALLS [id=1,mo,ACTIVE,voice,norm,129,0]
D/GSM ( 85): [GSMConn] update: parent=ACTIVE, hasNewParent=false, wasConnectingInOrOut=
false, wasHolding=false, isConnectingInOrOut=false, changed=false
D/RILJ ( 85): WAKE_LOCK_TIMEOUT mReqPending=0 mRequestList=1
D/GSM ( 85): [CallTracker] hangupForegroundResumeBackground
D/AT ( 22): AT> AT+CHLD=1
D/AT ( 22): AT< OK

PS. Above logs are all from emulator-5554! ATD: dial command in modem, AT+CLCC: List current calls, AT+CHLD: Releases all active calls

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