和你一起終身學(xué)習(xí)，這里是程序員Android

經(jīng)典好文推薦，通過閱讀本文，您將收獲以下知識點:

一、Camera 框架介紹：

Camera的框架分為Kernel部分和hal部分，其中kernel部分主要有兩塊：

image sensor driver，負(fù)責(zé)具體型號的sensor的id檢測，上電，以及在preview、capture、初始化、3A等等功能設(shè)定時的寄存器配置；
isp driver，通過DMA將sensor數(shù)據(jù)流上傳；

HAL層部分主要有三部分組成：

imageio，主要負(fù)責(zé)數(shù)據(jù)buffer上傳的pipe；
drv，包含imgsensor和isp的hal層控制；
feature io，包含各種3A等性能配置；

這篇內(nèi)容主要介紹開機過程中search sensor以及上電流程等內(nèi)容。

二、Camera 啟動流程

1、CameraService是在開機時啟動的，啟動后進(jìn)行searchSensor的操作，會search系統(tǒng)有多少camera，開機時的search操作，只進(jìn)行camera支持?jǐn)?shù)量的遍歷，以及sensor ID的讀取操作，如下是hal部分的ASTAH繪制調(diào)用流程圖，對應(yīng)的接口的文件路徑：

HalSensorList：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/HalSensorList.enumList.cpp
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/HalSensorList.cpp
SeninfDrv：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/mt6765/seninf_drv.cpp
SensorDrv：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/imgsensor_drv.cpp

(1) 這里先看enumerateSensor_Locked完成的工作，直接看代碼：

MUINT HalSensorList::searchSensors()
{
    Mutex::Autolock _l(mEnumSensorMutex);
    MY_LOGD("searchSensors");
    return  enumerateSensor_Locked();
}

MUINT HalSensorList::enumerateSensor_Locked()
{
    SensorDrv *const pSensorDrv = SensorDrv::get();
    SeninfDrv *const pSeninfDrv = SeninfDrv::createInstance();
    //初始化seninf,配置ISP相關(guān)內(nèi)容
    pSeninfDrv->init();

    //將所有的clk全部打開
    pSeninfDrv->setAllMclkOnOff(ISP_DRIVING_8MA, TRUE);

    pSensorDrv->init();
    for (MUINT i = IMGSENSOR_SENSOR_IDX_MIN_NUM; i <= max_index_of_camera; i++) {
        if((ret = pSensorDrv->searchSensor((IMGSENSOR_SENSOR_IDX)i)) == SENSOR_NO_ERROR){
            //query sensorinfo
           querySensorDrvInfo((IMGSENSOR_SENSOR_IDX)i);
           //fill in metadata
           buildSensorMetadata((IMGSENSOR_SENSOR_IDX)i);
           pSensorInfo = pSensorDrv->getSensorInfo((IMGSENSOR_SENSOR_IDX)i);
           addAndInitSensorEnumInfo_Locked(
                (IMGSENSOR_SENSOR_IDX)i,
                mapToSensorType(pSensorInfo->GetType()),
                pSensorInfo->getDrvMacroName());
        }
    }     
}

(２) 下面主要看下searchSensor的流程，這里有去獲取sensorList的內(nèi)容：

MINT32 ImgSensorDrv::searchSensor(IMGSENSOR_SENSOR_IDX sensorIdx)
{
    GetSensorInitFuncList(&pSensorInitFunc);

    featureControl(sensorIdx, SENSOR_FEATURE_SET_DRIVER, (MUINT8 *)&idx, &featureParaLen);

    NSFeature::SensorInfoBase* pSensorInfo = pSensorInitFunc[idx].pSensorInfo;
}

GetSensorInitFuncList是獲取到配置的sensorList的內(nèi)容，此sensorList需要與kernel層配置的一致，不一致的話在打開camera時會出現(xiàn)異常：
文件位置：
vendor/mediatek/proprietary/custom/mt6765/hal/imgsensor_src/sensorlist.cpp

MSDK_SENSOR_INIT_FUNCTION_STRUCT SensorList[] =
{
#if defined(IMX486_MIPI_RAW)
    RAW_INFO(IMX486_SENSOR_ID, SENSOR_DRVNAME_IMX486_MIPI_RAW, CAM_CALGetCalData),
#endif
//.....
}

UINT32 GetSensorInitFuncList(MSDK_SENSOR_INIT_FUNCTION_STRUCT **ppSensorList)
{
    if (NULL == ppSensorList) {
        ALOGE("ERROR: NULL pSensorList\n");
        return MHAL_UNKNOWN_ERROR;
    }
    *ppSensorList = &SensorList[0];
    return MHAL_NO_ERROR;
}

對應(yīng)的MSDK_SENSOR_INIT_FUNCTION_STRUCT的結(jié)構(gòu)體如下：

typedef struct
{
    MUINT32 sensorType;
    MUINT32 SensorId;
    MUINT8  drvname[32];
    NSFeature::SensorInfoBase* pSensorInfo;
    MUINT32 (*getCameraIndexMgr)(CAMERA_DATA_TYPE_ENUM CameraDataType, MVOID *pDataBuf, MUINT32 size);
    MUINT32 (*getCameraCalData)(UINT32* pGetSensorCalData);
} MSDK_SENSOR_INIT_FUNCTION_STRUCT, *PMSDK_SENSOR_INIT_FUNCTION_STRUCT;

(3) featureControl的setDriver流程：
文件位置：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/imgsensor_drv.cpp

MINT32  ImgSensorDrv::featureControl(
    IMGSENSOR_SENSOR_IDX sensorIdx,
    ACDK_SENSOR_FEATURE_ENUM FeatureId,
    MUINT8 *pFeaturePara,
    MUINT32 *pFeatureParaLen
)
{
    //結(jié)構(gòu)ACDK_SENSOR_FEATURECONTROL_STRUCT和kernel中一致
    featureCtrl.InvokeCamera = sensorIdx;
    featureCtrl.FeatureId = FeatureId;//SENSOR_FEATURE_SET_DRIVER
    featureCtrl.pFeaturePara = pFeaturePara;
    featureCtrl.pFeatureParaLen = pFeatureParaLen;

    if (ioctl(m_fdSensor, KDIMGSENSORIOC_X_FEATURECONCTROL , &featureCtrl) < 0) {
        LOG_ERR("[featureControl] Err-ctrlCode (%s)", strerror(errno));
        return -errno;
    }

    return SENSOR_NO_ERROR;
}

三、kernel 啟動流程

先來看整體的框架圖如下：

1、set clock 設(shè)置時鐘

static long imgsensor_ioctl(
    struct file *a_pstFile,
    unsigned int a_u4Command,
    unsigned long a_u4Param)
{
    case KDIMGSENSORIOC_X_SET_MCLK_PLL:
        i4RetValue = imgsensor_clk_set(
            &pgimgsensor->clk,
            (struct ACDK_SENSOR_MCLK_STRUCT *)pBuff);
        break;
        //......
}

int imgsensor_clk_set(
    struct IMGSENSOR_CLK *pclk, struct ACDK_SENSOR_MCLK_STRUCT *pmclk)
{
    if (pmclk->on) {
        clk_prepare_enable(pclk->imgsensor_ccf[mclk_index])
        ret = clk_set_parent(
            pclk->imgsensor_ccf[pmclk->TG],
            pclk->imgsensor_ccf[mclk_index]);
    } else {
        clk_disable_unprepare(pclk->imgsensor_ccf[mclk_index]);
    }
}

2、set driver

static long imgsensor_ioctl(
    struct file *a_pstFile,
    unsigned int a_u4Command,
    unsigned long a_u4Param) 
{
    case KDIMGSENSORIOC_X_FEATURECONCTROL:
        i4RetValue = adopt_CAMERA_HW_FeatureControl(pBuff);
        break;
        //......
}

static inline int adopt_CAMERA_HW_FeatureControl(void *pBuf)
{
    /* copy from user */
    switch (pFeatureCtrl->FeatureId) {
        case SENSOR_FEATURE_SET_DRIVER:
        {
            MINT32 drv_idx;

            psensor->inst.sensor_idx = pFeatureCtrl->InvokeCamera;
            drv_idx = imgsensor_set_driver(psensor);

            memcpy(pFeaturePara, &drv_idx, FeatureParaLen);
            break;
        }
    }
}

遍歷CONFIG_CUSTOM_KERNEL_IMGSENSOR的內(nèi)容，然后看sensorList是否對應(yīng)，并獲取對應(yīng)的下標(biāo)，調(diào)用imgsensor_check_is_alive進(jìn)行上下電并讀取ID 的操作：

struct IMGSENSOR_INIT_FUNC_LIST kdSensorList[MAX_NUM_OF_SUPPORT_SENSOR] = {
#if defined(XXXXXX_MIPI_RAW)
        {XXXXXX_SENSOR_ID,
        SENSOR_DRVNAME_XXXXXX_MIPI_RAW,
        XXXXXX_MIPI_RAW_SensorInit},
#endif
    //......
}

int imgsensor_set_driver(struct IMGSENSOR_SENSOR *psensor)
{
    struct IMGSENSOR_SENSOR_INST    *psensor_inst = &psensor->inst;
    struct IMGSENSOR_INIT_FUNC_LIST *pSensorList  = kdSensorList;
    //獲取config的size
    char *sensor_configs = STRINGIZE(CONFIG_CUSTOM_KERNEL_IMGSENSOR);
    imgsensor_i2c_init(&psensor_inst->i2c_cfg,
    imgsensor_custom_config[psensor->inst.sensor_idx].i2c_dev);

    memcpy(psensor_list_config, sensor_configs+1, strlen(sensor_configs)-2);
    //對應(yīng)config字符串進(jìn)行按空格進(jìn)行拆解
    driver_name = strsep(&psensor_list_config, " \0");

    while (driver_name != NULL) {
        for (j = 0; j < MAX_NUM_OF_SUPPORT_SENSOR; j++) {
            //判斷對應(yīng)的init函數(shù)是否存在
            if (pSensorList[j].init == NULL)
                break;
            else if (!strcmp(driver_name, pSensorList[j].name)) {
                //如果在config中和sensorlist中同時有定義進(jìn)行賦值
                orderedSearchList[i++] = j;
                break;
            }
        }
        driver_name = strsep(&psensor_list_config, " \0");
    }

    for (i = 0; i < MAX_NUM_OF_SUPPORT_SENSOR; i++) {
        //上面獲取到的sensorlist的下標(biāo)
        drv_idx = orderedSearchList[i];
        if (pSensorList[drv_idx].init) {
            //調(diào)用對應(yīng)驅(qū)動的init函數(shù)
            pSensorList[drv_idx].init(&psensor->pfunc);
            if (psensor->pfunc) {
                psensor_inst->psensor_name =
                    (char *)pSensorList[drv_idx].name;
                    //到這里是重點，進(jìn)行上電讀取ID的操作
                if (!imgsensor_check_is_alive(psensor)) {
                    ret = drv_idx;
                }
            }
        }
    }
}

下面看對應(yīng)的上下電以及讀取ID的操作：

static inline int imgsensor_check_is_alive(struct IMGSENSOR_SENSOR *psensor)
{
    struct IMGSENSOR_SENSOR_INST  *psensor_inst = &psensor->inst;
    //上電
    err = imgsensor_hw_power(&pgimgsensor->hw,
                psensor,
                psensor_inst->psensor_name,
                IMGSENSOR_HW_POWER_STATUS_ON);
    //讀取ID
    imgsensor_sensor_feature_control(
            psensor,
            SENSOR_FEATURE_CHECK_SENSOR_ID,
            (MUINT8 *)&sensorID,
            &retLen);

    if (sensorID == 0 || sensorID == 0xFFFFFFFF) {
        pr_info("Fail to get sensor ID %x\n", sensorID);
        err = ERROR_SENSOR_CONNECT_FAIL;
    } else {
        pr_info(" Sensor found ID = 0x%x\n", sensorID);
        err = ERROR_NONE;
    }
    //下電
    imgsensor_hw_power(&pgimgsensor->hw,
        psensor,
        psensor_inst->psensor_name,
        IMGSENSOR_HW_POWER_STATUS_OFF);

    return err ? -EIO:err;
}

3、上電相關(guān)

上電時序配置：

struct IMGSENSOR_HW_POWER_INFO {
    enum IMGSENSOR_HW_PIN       pin;
    enum IMGSENSOR_HW_PIN_STATE pin_state_on;
    u32  pin_on_delay;
    enum IMGSENSOR_HW_PIN_STATE pin_state_off;
    u32  pin_off_delay;
};

struct IMGSENSOR_HW_POWER_SEQ sensor_power_sequence[] = {
    //……
    #if defined(XXXXXX_MIPI_RAW)
        {
            SENSOR_DRVNAME_XXXXXX_MIPI_RAW,
            {
                {RST, Vol_Low, 0},
                {DVDD, Vol_1100, 1},
                {AVDD, Vol_2800, 1},
                {DOVDD, Vol_1800, 1},
                {RST, Vol_High, 1},
                {SensorMCLK, Vol_High, 0},
            },
        },
    #endif
}

對應(yīng)的控制的流程如下：

static enum IMGSENSOR_RETURN imgsensor_hw_power_sequence(
    struct IMGSENSOR_HW             *phw,
    enum   IMGSENSOR_SENSOR_IDX      sensor_idx,
    enum   IMGSENSOR_HW_POWER_STATUS pwr_status,
    struct IMGSENSOR_HW_POWER_SEQ   *ppower_sequence,
    char *pcurr_idx)
{
    ppwr_info = ppwr_seq->pwr_info;
    // 上電
    while (ppwr_info->pin != IMGSENSOR_HW_PIN_NONE &&
        ppwr_info < ppwr_seq->pwr_info + IMGSENSOR_HW_POWER_INFO_MAX) {

        if (pwr_status == IMGSENSOR_HW_POWER_STATUS_ON &&
           ppwr_info->pin != IMGSENSOR_HW_PIN_UNDEF) {
            pdev = phw->pdev[psensor_pwr->id[ppwr_info->pin]];
            if (pdev->set != NULL)
                //調(diào)用GPIO或者regulator的set 電壓操作，這里的pdev在imgsensor_probe中已經(jīng)設(shè)置
                pdev->set( 
                    pdev->pinstance,
                    sensor_idx,
                    ppwr_info->pin,
                    ppwr_info->pin_state_on);

            mdelay(ppwr_info->pin_on_delay);
        }
        // 從上到下依次上電
        ppwr_info++;
        pin_cnt++;
    }

    // 下電操作
    if (pwr_status == IMGSENSOR_HW_POWER_STATUS_OFF) {
        while (pin_cnt) {
            //從下到上依次下電
            ppwr_info--;
            pin_cnt--;

            if (ppwr_info->pin != IMGSENSOR_HW_PIN_UNDEF) {
                pdev =
                    phw->pdev[psensor_pwr->id[ppwr_info->pin]];
                mdelay(ppwr_info->pin_on_delay);

                if (pdev->set != NULL)
                    pdev->set(
                        pdev->pinstance,
                        sensor_idx,
                        ppwr_info->pin,
                        ppwr_info->pin_state_off);
            }
        }
    }

    /* wait for power stable */
    if (pwr_status == IMGSENSOR_HW_POWER_STATUS_ON)
        mdelay(5);
    return IMGSENSOR_RETURN_SUCCESS;
}

四、總結(jié)

通過上面的代碼流程，可以知道上開機時，camera模塊先會將所有的MCLK打開，然后對依次對對應(yīng)的sensor進(jìn)行上電，讀取ID(判斷I2C是否正常通訊)。這部分調(diào)試過程中遇到的問題總結(jié)如下：

1、ID讀取不到，I2C不通

檢查上電時序，３項電壓（AVDD/DVDD/IOVDD）是否正確；
I2C地址及通道設(shè)置是否正確；
檢查cfg_setting_imgsensor.cpp中MCLK和HW鏈接配置是否正確；

2、Camera 啟動時間過長

檢查Sensor上電時序要求的延時，是否有偏長的情況；
去掉多余的I2C地址，因為大部分驅(qū)動會多添加一些地址；
OTP的加載調(diào)整到每次開機時第一次打開加載，之后不加載；
sensorInit如果時間過長，可以調(diào)節(jié)I2C speed(400->1000)；

3、preview 階段耗時

檢查streamOn/Off的耗時；
preview_init是否有較長時間的耗時
以及延時操作使用mdelay代替msleep；
pre_delay_frame/cap_delay_frame丟幀操作是否合適；

4、低電流、功耗相關(guān)問題

檢查電壓是否都有下電成功，防止漏電；
對于共pin的sensor，在操作時是否有做好workaround；
將I2C寄存器單個讀寫，調(diào)整為連續(xù)讀寫的方式也有一定優(yōu)化；
sensor的PIN是否有被其他模塊占用，異常操作的行為；

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