I.MX6 Android U-blox miniPCI 4G porting

/**************************************************************************
 *                I.MX6 Android U-blox miniPCI 4G porting
 * 声明：
 *     在移植U-blox的4G模块的过程中遇到了不少的问题，有不少是自己的这边疏忽
 * 的问题，无论怎么说，问题解决了就行。
 *
 *                                       2016-1-11 深圳 南山平山村 曾剑锋
 *************************************************************************/

一、参考文档：
    . 飞思卡尔i.MX 6Quad Android 4.0.4的3G驱动移植
        http://blog.csdn.net/xnwyd/article/details/9498235
    . 关于 android RIL 调试
        http://blog.lytsing.org/archives/476.html

二、ublox设备miniPCI识别到的设备节点：
    . 只有一个: /dev/ttyACM0.
    . 原因如下：
        the USB mode of MPCI-L210 module in "RNDIS" mode, so it will only create one and only one ttyACM0 node. If you need to use ttyACM0, ttyACM1 and ttyACM2. please execute following command:
            // Set USB configuration to "fairly back-compatible" and disable the audio over USB.
            . AT+UUSBCONF=,””,
            // It need reboot the module.
            . AT+CFUN=
            // this command will reboot the module, or you can reboot device instead of.
            . AT+UUSBCONF?
        For more detail description, please check attach file(AT-CommandExample), chapter  USB profile configuration. 

三、重新配置ublox：
    . 参考《AT Commands Examples Examples for u-blox cellular modules Application Note》;
    . chapter  USB profile configuration: Fairly back-compatible profile
        This is the configuration (<id>=) similar to the one implemented in the u-blox LISA-U series. The interfaces available are:
            .  CDC-ACM for AT command and data
            .  CDC-ACM for GNSS tunnelling
            .  CDC-ACM for SIM Access profile (SAP)
            .  CDC-ACM for diagnostic
        This configuration is identified by:
            VID = 0x1546
            PID = 0x1141
        省略后面的命令说明...
    . 使用串口工具，对ublox进行配置，我使用的是自己之前写的命令行的串口工具，参考：《I.MX6 Android Linux UART send receive with multi-thread and multi-mode demo》
        root@android:/data/local # ./autorun.sh
        serialString : /dev/ttyACM0.
        baudRate .
        workMode: send and recv.
        AT+UUSBCONF=,"",

        OK

    . dmesg信息提示如下：
        ......
        usb -1.4: new high speed USB device number  using fsl-ehci
        imx-ipuv3 imx-ipuv3.: IPU DMFC DP HIGH RESOLUTION: (,), 5B(~), 5F(,)
        cdc_acm -1.4:1.0: This device cannot do calls on its own. It is not a modem.
        cdc_acm -1.4:1.0: ttyACM0: USB ACM device
        cdc_acm -1.4:1.2: This device cannot do calls on its own. It is not a modem.
        cdc_acm -1.4:1.2: ttyACM1: USB ACM device
        cdc_acm -1.4:1.4: This device cannot do calls on its own. It is not a modem.
        cdc_acm -1.4:1.4: ttyACM2: USB ACM device
        cdc_acm -1.4:1.6: This device cannot do calls on its own. It is not a modem.
        cdc_acm -1.4:1.6: ttyACM3: USB ACM device
        cdc_acm -1.4:1.8: This device cannot do calls on its own. It is not a modem.
        cdc_acm -1.4:1.8: ttyACM4: USB ACM device
        cdc_acm -1.4:1.10: This device cannot do calls on its own. It is not a modem.
        cdc_acm -1.4:1.10: ttyACM5: USB ACM device
        ......
    . 厂家的FAE说上面的错误可以不用关心
        This device cannot do calls on its own. It is not a modem.

四、配置Android系统：
    . 参考文档：《Android RIL Production delivery – Source code Application Note》
    . 参考章节：Appendix - D Android 4.1/ 4.2 / 4.3 / 4.4 module configuration
        To enable the USB module connection, configure Ueventd.[platform].rc, AndroidProducts.mk and init.rc files as described in sections below. Before changing the files, below are some necessary steps to follow.

五、Error：
    . Error1：
        . 出错信息：
            init: cannot execve('/system/bin/uril-repo.sh'): No such file or directory
        . 查看uril-repo.sh文件：busybox vi uril-repo.sh
            #!/system/bin/sh^M
            ^M
            URIL_REPO_DST=/data/uril/repository.txt^M
            ^M
            rril_repo_missing=`ls $URIL_REPO_DST`true^M
            ^M
            if (${rril_repo_missing}) ; then^M
                    mkdir /data/uril^M
                    chmod  /data/uril^M
                    cat /etc/uril/repository.txt > $URIL_REPO_DST^M
                    chmod  $URIL_REPO_DST^M
                    sync^M
                    /system/bin/log -t RIL-repo "created $URIL_REPO_DST"^M
            else^M
                    /system/bin/log -t RIL-repo "$URIL_REPO_DST exists"^M
            fi^M
            ^M
            # set this property after checking that repository exists or after it's created^
            # This is checked in rildmain mainloop during RIL_Init^M
            /system/bin/setprop "net.uril.repository" "ready"^M
            ^M
            # set this property to configure emergency number if required^M
            #/system/bin/setprop "ril.ecclist" "111,112,113,115,117,118,119,122,125,127,911,
            - uril-repo.sh / %
        . 通过查看文件，发现其中的每行最后都多出了^M这个字符，貌似这个文件是在Windows上面编辑的。
        . 删除这些^M。
        . 但是这个字符在Ubuntu、Vim中都看不到，这貌似有点奇怪。
        . 有点忧伤的地方在于U-Blox提供的etc下的配置文件都是这种文件，他们提供错了文档。
    . Error2:
        . adb logcat -v time -b radio > logcat_info.txt
        . 错误信息：
            - ::05.570 I/RIL     ( ): 3G modem monitor thread is start

            - ::05.570 E/RILD    ( ): dlopen failed: Cannot load library: load_library(linker.cpp:): library "/system/lib/libhuawei-ril.so" not found

            - ::05.620 I/RIL-repo( ): created /data/uril/repository.txt 

            - ::10.100 E/RILD    ( ): dlopen failed: Cannot load library: load_library(linker.cpp:): library "/system/lib/libhuawei-ril.so" not found

            ......
        . cat hardware/ril/rild/rild.c
            ......
            // #define REFERENCE_RIL_DEF_PATH "/system/lib/libhuawei-ril.so"
            ......
            int main(int argc, char **argv)
            {
                ......
                switch (modem_type){
                    case ZTE_MODEM:
                    rilLibPath = REFERENCE_RIL_ZTE_PATH;
                    break;

                    case HUAWEI_MODEM:
                    case AMAZON_MODEM:
                    default:
                    rilLibPath = REFERENCE_RIL_DEF_PATH;
                    break;
                }
                ......
            }
        . 修改REFERENCE_RIL_DEF_PATH的值为：
            "/system/lib/librapid-ril-core.so"
        . 根据rild.c中代码的运行流程可知，命令行中的-l参数是无效。
    . 能够获取GSM信号，但无法获取网络数据：
        . 模块问题检查：
            root@android:/data/local # ./autorun.sh
            CMD: AT+UUSBCONF?.

            +UUSBCONF: ,"RNDIS",,"0x1146"

            OK
            CMD: AT+UUSBCONF=,"",.

            OK
            CMD: AT+CFUN=.
            usb -1.4: USB disconnect, device number
            usb -1.4: new high speed USB device number  using fsl-ehci
            usb -1.4: USB disconnect, device number
            usb -1.4: new high speed USB device number  using fsl-ehci
            cdc_acm -1.4:1.0: This device cannot do calls on its own. It is not a modem.
            cdc_acm -1.4:1.0: ttyACM0: USB ACM device
            cdc_acm -1.4:1.2: This device cannot do calls on its own. It is not a modem.
            cdc_acm -1.4:1.2: ttyACM1: USB ACM device
            cdc_acm -1.4:1.4: This device cannot do calls on its own. It is not a modem.
            cdc_acm -1.4:1.4: ttyACM2: USB ACM device
            cdc_acm -1.4:1.6: This device cannot do calls on its own. It is not a modem.
            cdc_acm -1.4:1.6: ttyACM3: USB ACM device
            cdc_acm -1.4:1.8: This device cannot do calls on its own. It is not a modem.
            cdc_acm -1.4:1.8: ttyACM4: USB ACM device
            cdc_acm -1.4:1.10: This device cannot do calls on its own. It is not a modem.
            cdc_acm -1.4:1.10: ttyACM5: USB ACM device
            CMD: AT+UUSBCONF?.

            +UUSBCONF: ,"",,"0x1141"

            OK
            usb -1.4: USB disconnect, device number
            usb -1.4: new high speed USB device number  using fsl-ehci
            usb -1.4: USB disconnect, device number
            usb -1.4: new high speed USB device number  using fsl-ehci
            cdc_acm -1.4:1.2: This device cannot do calls on its own. It is not a modem.
            cdc_acm -1.4:1.2: ttyACM0: USB ACM device
            CMD: AT+UUSBCONF?.
            AT+UUSBCONF?
            +UUSBCONF: ,"RNDIS",,"0x1146"

            OK

            ATE0V1
            OK
        . 从1中可以看出：
            将模块设置为Fairly back-compatible模式的时候，移植的系统又会自动将模块
            重置为High throughput模式，无法稳定工作在Fairly back-compatible模式。
        . 原因是 "hardware/ril/ublox_ril/CORE/ND/systemmanager.cpp” 的 1729 行.
        . 解决办法：
            . 参考《AndroidRIL-SourceCode_AppNote.pdf》中"章节 I, Repository file configuration".
            . cat build/target/product/rootdir/etc/uril/repository.txt
                ......
                // Modem settings
                Group Modem
                    SupportedModem              UbloxModem
                    //NetworkInterfaceName        USB     // 修改为ppp
                    NetworkInterfaceName        ppp
                    DisableModemReset
                ......
                // USB Profile Configuration
                Group USBUBM
                    // 将RNDIS模式修改为CDC-ACM模式
                    // USBCONF                     3    // 0: CDC-ACM, 2: CDC-ECM, 3: RNDIS
                    USBCONF                         // 0: CDC-ACM, 2: CDC-ECM, 3: RNDIS
                    UBMCONF                // 1: Router,  2: Bridge
                ......