1、前言
本文主要研究展讯平台Camera驱动和HAL层代码架构，熟悉展讯Camera的控制流程。
平台：Sprd-展讯平台
Hal版本：【HAL3】
知识点以下：
从HAL层到deiver层
1.Camera的打开(open)、初始化(init)和供电(power on)调用流程
2.预览(preview)调用流程
3.拍照(snapshot)调用流程c++
Camera软件架构
camera软件架构架构
2、Camera的打开(open)和初始化(init)调用流程
2.1 framework层的入口
通过App->framework层->jni层->cameraservice这个过程，接着调用到:
frameworks/av/services/camera/libcameraservice/device3/Camera3Device.cppapp
status_t Camera3Device::initialize(camera_module_t *module)
{
...
/** Open HAL device */
status_t res;
String8 deviceName = String8::format("%d", mId);
camera3_device_t *device;
//这里调用modules->open函数打开摄像头
res = module->common.methods->open(&module->common, deviceName.string(),
reinterpret_cast<hw_device_t**>(&device));
if (res != OK) {
SET_ERR_L("Could not open camera: %s (%d)", strerror(-res), res);
return res;
}
...
}
这里调用module->common.methods->open开始操做HAL层，咱们继续往下看ide
2.2 HAL层
vendor/sprd/modules/libcamera/hal3_2v1/SprdCamera3Factory.cpp函数
struct hw_module_methods_t SprdCamera3Factory::mModuleMethods = {
.open = SprdCamera3Factory::camera_device_open,
};
其实是调用的SprdCamera3Factory::camera_device_open方法。post
int SprdCamera3Factory::camera_device_open(const struct hw_module_t *module,
const char *id,
struct hw_device_t **hw_device) {
···
if (isSingleIdExposeOnMultiCameraMode(atoi(id))) {
return gSprdCamera3Wrapper->cameraDeviceOpen(module, id, hw_device);
} else {
return gSprdCamera3Factory.cameraDeviceOpen(atoi(id), hw_device);
}
···
}
这里open a camera device by its ID，经过ID来打开摄像头(后主摄：0 后副摄：2 前主摄：1 前副摄：3)ui
IDthis
接着继续调用gSprdCamera3Factory.cameraDeviceOpen();spa
int SprdCamera3Factory::cameraDeviceOpen(int camera_id,
struct hw_device_t **hw_device) {
···
SprdCamera3HWI *hw =
new SprdCamera3HWI(multiCameraModeIdToPhyId(camera_id));
rc = hw->openCamera(hw_device);
···
return rc;
}
这里new了一个SprdCamera3HWI的实例，而后调用openCamera(hw_device)方法。线程
vendor/sprd/modules/libcamera/hal3_2v1/SprdCamera3HWI.cpp
int SprdCamera3HWI::openCamera(struct hw_device_t **hw_device) {
···
ret = openCamera();
if (ret == 0) {
*hw_device = &mCameraDevice.common;
mCameraSessionActive++;
} else
*hw_device = NULL;
···
return ret;
}
接着继续调用空构造方法openCamera();
int SprdCamera3HWI::openCamera() {
···
//new SprdCamera3OEMIf的实例
mOEMIf = new SprdCamera3OEMIf(mCameraId, mSetting);
mOEMIf->camera_ioctrl(CAMERA_IOCTRL_SET_MULTI_CAMERAMODE, &mMultiCameraMode,
NULL);
//打开mOEMIf->openCamera()方法
ret = mOEMIf->openCamera();
mCameraOpened = true;
···
if (mOEMIf->isIspToolMode()) {
mOEMIf->ispToolModeInit();//初始化ispToolMode
startispserver(mCameraId);
ispvideo_RegCameraFunc(1, ispVideoStartPreview);//注册ispVideoStartPreview函数
ispvideo_RegCameraFunc(2, ispVideoStopPreview);//注册ispVideoStopPreview 函数
ispvideo_RegCameraFunc(3, ispVideoTakePicture);//注册 ispVideoTakePicture函数
ispvideo_RegCameraFunc(4, ispVideoSetParam);//注册 ispVideoSetParam函数
}
···
return NO_ERROR;
}
这里new SprdCamera3OEMIf的实例，继续调用mOEMIf->openCamera()方法。
vendor/sprd/modules/libcamera/hal3_2v1/SprdCamera3OEMIf.cpp
int SprdCamera3OEMIf::openCamera() {
···
//设置宽和高
mSetting->getLargestPictureSize(mCameraId, &picW, &picH);
mSetting->getLargestSensorSize(mCameraId, &snsW, &snsH);
if (picW * picH > snsW * snsH) {
mLargestPictureWidth = picW;
mLargestPictureHeight = picH;
} else {
mLargestPictureWidth = snsW;
mLargestPictureHeight = snsH;
}
//设置最大尺寸
mHalOem->ops->camera_set_largest_picture_size(
mCameraId, mLargestPictureWidth, mLargestPictureHeight);
//调用startCameraIfNecessary继续启动摄像头
if (!startCameraIfNecessary()) {
ret = UNKNOWN_ERROR;
HAL_LOGE("start failed");
goto exit;
}
//零延时模式线程初始化
ZSLMode_monitor_thread_init((void *)this);
#ifdef CONFIG_CAMERA_GYRO
gyro_monitor_thread_init((void *)this);
#endif
property_get("persist.sys.camera.raw.mode", value, "jpeg");
if (!strcmp(value, "raw") || !strcmp(value, "bin")) {
is_raw_capture = 1;
}
property_get("persist.sys.isptool.mode.enable", value, "false");
if (!strcmp(value, "true") || is_raw_capture) {
mIsIspToolMode = 1;
}
···
}
SprdCamera3OEMIf::openCamera主要作了如下事情：
1.设置图像的最大尺寸
2.调用startCameraIfNecessary继续启动摄像头
3.零延时模式线程初始化
4.根据persist.sys.camera.raw.mode和persist.sys.isptool.mode.enable设置属性
继续根据startCameraIfNecessary方法，这个方法作了不少事情，有些复杂。
bool SprdCamera3OEMIf::startCameraIfNecessary() {
···
//若是camera没有初始化，进行初始化
if (!isCameraInit()) {
HAL_LOGI("wait for camera_init");
if (CMR_CAMERA_SUCCESS !=
mHalOem->ops->camera_init(mCameraId, camera_cb, this, 0,
&mCameraHandle, (void *)Callback_Malloc,
(void *)Callback_Free)) {
setCameraState(SPRD_INIT);
HAL_LOGE("CameraIfNecessary: fail to camera_init().");
return false;
} else {
setCameraState(SPRD_IDLE);
}
···
//得到零延时快拍的相关参数
mHalOem->ops->camera_get_zsl_capability(mCameraHandle, &is_support_zsl,
&max_width, &max_height);
//判断是否支持零延时
if (!is_support_zsl) {
mParameters.setZSLSupport("false");
}
// 获取抓取能力，包含3dnr能力
mHalOem->ops->camera_ioctrl(
mCameraHandle, CAMERA_IOCTRL_GET_GRAB_CAPABILITY, &grab_capability);
/*从oem层获取传感器和镜头信息*/
mHalOem->ops->camera_get_sensor_exif_info(mCameraHandle, &exif_info);
mSetting->getLENSTag(&lensInfo);
lensInfo.aperture = exif_info.aperture;
mSetting->setLENSTag(lensInfo);
/*从oem层获取传感器otp*/
/*开始读取refoucs模式*/
if (MODE_SINGLE_CAMERA != mMultiCameraMode &&
MODE_3D_CAPTURE != mMultiCameraMode &&
MODE_BLUR != mMultiCameraMode && MODE_BOKEH != mMultiCameraMode) {
mSprdRefocusEnabled = true;
CMR_LOGI("mSprdRefocusEnabled %d", mSprdRefocusEnabled);
}
/*结束读取refoucs模式*/
/*从oem层 获取OPT信息 开始 */
if ((MODE_BOKEH == mMultiCameraMode || mSprdRefocusEnabled == true) &&
mCameraId == 0) {
OTP_Tag otpInfo;
memset(&otpInfo, 0, sizeof(OTP_Tag));
mSetting->getOTPTag(&otpInfo);
···
struct sensor_otp_cust_info otp_info;
memset(&otp_info, 0, sizeof(struct sensor_otp_cust_info));
mHalOem->ops->camera_get_sensor_otp_info(mCameraHandle, &otp_info);
···
}
/*从oem 层获取OTP信息 结束*/
/**添加3d校准，获取最大传感器尺寸*/
mSetting->getSPRDDEFTag(&sprddefInfo);
mHalOem->ops->camera_get_sensor_info_for_raw(mCameraHandle, mode_info);
for (i = SENSOR_MODE_PREVIEW_ONE; i < SENSOR_MODE_MAX; i++) {
HAL_LOGD("trim w=%d, h=%d", mode_info[i].trim_width,
mode_info[i].trim_height);
if (mode_info[i].trim_width * mode_info[i].trim_height >=
sprddefInfo.sprd_3dcalibration_cap_size[0] *
sprddefInfo.sprd_3dcalibration_cap_size[1]) {
sprddefInfo.sprd_3dcalibration_cap_size[0] =
mode_info[i].trim_width;
sprddefInfo.sprd_3dcalibration_cap_size[1] =
mode_info[i].trim_height;
}
}
···
return true;
}
该函数已经在相应位置添加代码注释，咱们继续关注调用流程，经过mHalOem->ops->camera_init最终会调用到SprdOEMCamera.c代码的camera_init进行初始化
vendor/sprd/modules/libcamera/oem2v1/src/SprdOEMCamera.c
cmr_int camera_init(cmr_u32 camera_id, camera_cb_of_type callback,
void *client_data, cmr_uint is_autotest,
cmr_handle *camera_handle, void *cb_of_malloc,
void *cb_of_free) {
···
//初始化OEM的log
oem_init_log_level();
//调用camera_local_int继续进行初始化
ret = camera_local_int(camera_id, callback, client_data, is_autotest,
camera_handle, cb_of_malloc, cb_of_free);
···
//其余的一些初始化
camera_lls_enable(*camera_handle, 0);
camera_set_lls_shot_mode(*camera_handle, 0);
camera_vendor_hdr_enable(*camera_handle, 0);
···
return ret;
}
vendor/sprd/modules/libcamera/oem2v1/src/cmr_oem.c
cmr_int camera_local_int(cmr_u32 camera_id, camera_cb_of_type callback,
void *client_data, cmr_uint is_autotest,
cmr_handle *oem_handle, void *cb_of_malloc,
void *cb_of_free) {
···
//内存申请
struct camera_context *cxt = NULL;
*oem_handle = (cmr_handle)0;
cxt = (struct camera_context *)malloc(sizeof(struct camera_context));
//参数赋值
cmr_bzero(cxt, sizeof(*cxt));
cxt->camera_id = camera_id;
cxt->camera_cb = callback;
cxt->client_data = client_data;
cxt->hal_malloc = cb_of_malloc;
cxt->hal_free = cb_of_free;
cxt->hal_gpu_malloc = NULL;
cxt->is_multi_mode = is_multi_camera_mode_oem;
cxt->blur_facebeauty_flag = 0;
//调用camera_init_internal进行下一步初始化
ret = camera_init_internal((cmr_handle)cxt, is_autotest);
···
return ret;
}
调用camera_init_internal进行下一步初始化
cmr_int camera_init_internal(cmr_handle oem_handle, cmr_uint is_autotest) {
···
//sensor初始化
ret = camera_sensor_init(oem_handle, is_autotest);
if (ret) {
CMR_LOGE("failed to init sensor %ld", ret);
goto exit;
}
//grab初始化
ret = camera_grab_init(oem_handle);
if (ret) {
CMR_LOGE("failed to init grab %ld", ret);
goto sensor_deinit;
}
//res初始化
ret = camera_res_init(oem_handle);
if (ret) {
CMR_LOGE("failed to init res %ld", ret);
goto grab_deinit;
}
//isp初始化
ret = camera_isp_init(oem_handle);
if (ret) {
CMR_LOGE("failed to init isp %ld", ret);
goto res_deinit;
}
//初始化完成
ret = camera_res_init_done(oem_handle);
···
return ret;
}
该函数主要作了如下事情:
1.sensor初始化
2.grab初始化
3.res初始化
4.isp初始化
咱们继续关注camera_sensor_init这个函数
cmr_int camera_sensor_init(cmr_handle oem_handle, cmr_uint is_autotest) {
···
ret = cmr_sensor_init(&init_param, &sensor_handle);
ret = cmr_sensor_open(sensor_handle, camera_id_bits);
···
}
该函数分别调用了cmr_sensor_init初始化和cmr_sensor_open打开Camera
vendor/sprd/modules/libcamera/oem2v1/src/cmr_sensor.c
cmr_int cmr_sensor_init(struct sensor_init_param *init_param_ptr,
cmr_handle *sensor_handle) {
···
/*save init param*/
handle->oem_handle = init_param_ptr->oem_handle;
handle->sensor_bits = init_param_ptr->sensor_bits;
handle->private_data = init_param_ptr->private_data;
handle->is_autotest = init_param_ptr->is_autotest;
/*create thread*/
ret = cmr_sns_create_thread(handle);
···
return ret;
}
该函数 对一些参数进行赋值，而后调用cmr_sns_create_thread方法建立cmr_sns_thread_proc线程。以下：
ret = cmr_thread_create(&handle->thread_cxt.thread_handle,
SENSOR_MSG_QUEUE_SIZE,cmr_sns_thread_proc,
(void *)handle)
cmr_int cmr_sensor_open(cmr_handle sensor_handle, cmr_u32 sensor_id_bits) {
···
struct cmr_sensor_handle *handle =
(struct cmr_sensor_handle *)sensor_handle;
/*the open&close function should be sync*/
message.msg_type = CMR_SENSOR_EVT_OPEN;
message.sync_flag = CMR_MSG_SYNC_PROCESSED;
message.data = (void *)((unsigned long)sensor_id_bits);
//这里发送msg消息，去启动在cmr_sensor_init建立的
ret = cmr_thread_msg_send(handle->thread_cxt.thread_handle, &message);
···
return ret;
}
在cmr_sensor_open中，发送了msg消息，去启动在cmr_sensor_init建立的线程cmr_sns_thread_proc。
这里的消息类型是message.msg_type = CMR_SENSOR_EVT_OPEN;
cmr_int cmr_sns_thread_proc(struct cmr_msg *message, void *p_data) {
···
switch (evt) {
case CMR_SENSOR_EVT_INIT:
/*common control info config*/
CMR_LOGI("INIT DONE!");
break;
case CMR_SENSOR_EVT_OPEN:
/*camera sensor open for every bits*/
ops_param = (cmr_u32)((unsigned long)message->data);
ret = cmr_sns_open(handle, ops_param);
if (ret) {
/* notify oem through fd_sensor */
CMR_LOGE("cmr_sns_open failed!");
}
return CMR_CAMERA_INVALID_PARAM;
}
···
}
所以，接下来会走case CMR_SENSOR_EVT_OPEN这个分支，调用cmr_sns_open方法。
cmr_int cmr_sns_open(struct cmr_sensor_handle *handle, cmr_u32 sensor_id_bits) {
···
/*open all signed camera sensor*/
for (cameraId = 0; cameraId < CAMERA_ID_MAX; cameraId++) {
if (0 != (sensor_id_bits & (1 << cameraId))) {
ret = sensor_open_common(&handle->sensor_cxt[cameraId], cameraId,
handle->is_autotest);
if (ret) {
CMR_LOGE("camera %u open failed!", cameraId);
} else {
handle->sensor_bits |= (1 << cameraId);
}
}
}
···
}
cmr_sns_open方法又继续调用sensor_open_common函数，这个函数比较复杂，主要工做以下：
1.初始化ctx(context)这个结构体
2.初始化exif信息(拍照信息)
3.加载sensor file文件，里面保存了camera的id
4.根据sensor file里保存的camera 的id打开摄像头
咱们来看代码：
vendor/sprd/modules/libcamera/sensor/sensor_drv_u.c
cmr_int sensor_open_common(struct sensor_drv_context *sensor_cxt,
cmr_u32 sensor_id, cmr_uint is_autotest) {
···
/* 调用sensor_context_init 初始化ctx(context)这个结构体*/
ret_val = sensor_context_init(sensor_cxt, sensor_id, is_autotest);
/* 建立sensor_ctrl_thread_proc线程. */
ret_val = sensor_create_ctrl_thread(sensor_cxt);
/* 初始化内核驱动程序的结构体hw_drv_init_para . */
struct hw_drv_init_para input_ptr;
cmr_int fd_sensor = SENSOR_FD_INIT;//SENSOR_FD_INIT =-1
cmr_handle hw_drv_handle = NULL;
input_ptr.sensor_id = sensor_id;
input_ptr.caller_handle = sensor_cxt;
fd_sensor = hw_sensor_drv_create(&input_ptr, &hw_drv_handle);
if ( (SENSOR_FD_INIT == fd_sensor) || (NULL == hw_drv_handle) ) {
SENSOR_LOGE("sns_device_init %d error, return", sensor_id);
ret_val = SENSOR_FAIL;
goto init_exit;
}
//初始化sensor_cxt
sensor_cxt->fd_sensor = fd_sensor;
sensor_cxt->hw_drv_handle = hw_drv_handle;
sensor_cxt->sensor_hw_handler = hw_drv_handle;
/* 根据存储在传感器idx文件中的索引加载全部传感器ic信息*/
sensor_load_idx_inf_file(sensor_cxt);
if (sensor_cxt->sensor_identified) {
if (SENSOR_SUCCESS == sns_load_drv(sensor_cxt, SENSOR_MAIN)){
sensor_num++;
}
···
SENSOR_LOGI("1 is identify, register OK");
/*读到id信息，就去open*/
ret_val = sensor_open(sensor_cxt, sensor_id);
if (ret_val != SENSOR_SUCCESS) {
SENSOR_LOGI("first open sensor failed,start identify");
}
}
/* 扫描cfg表中的设备，找出正确的传感器驱动程序 */
if ((!sensor_cxt->sensor_identified) || (ret_val != SENSOR_SUCCESS)) {
sensor_num = 0;
SENSOR_LOGI("register sensor fail, start identify");
//遍历的核心函数是sensor_identify
if (sensor_identify(sensor_cxt, SENSOR_MAIN))
sensor_num++;
···
//遍历成功后，继续执行sensor_open动做
ret_val = sensor_open(sensor_cxt, sensor_id);
}
sensor_cxt->sensor_identified = SCI_TRUE;//设置sensor_id的状态为TRUE
sensor_save_idx_inf_file(sensor_cxt);//把识别到的id信息保存到/data/misc/cameraserver/sensor.file
//把节点信息保存到/sys/devices/virtual/misc/sprd_sensor/camera_sensor_name
sensor_rid_save_sensor_info(sensor_cxt);
···
return ret_val;
}
分析：首先进行一些必要的初始化，而后调用sensor_load_idx_inf_file函数去加载/data/misc/cameraserver/路径下的sensor.file文件，
1.若是读到了sensor_id， sensor_cxt->sensor_identified 设置为SCI_TRUE(这个值是1)，走sns_load_drv(sensor_cxt, SENSOR_MAIN)函数去注册驱动程序，接着直接执行sensor_open动做。
2.不然，调用sensor_identify(sensor_cxt, SENSOR_MAIN)遍历sensor list，扫描cfg表中的设备，找出正确的传感器驱动程序。
以上成功后，调用sensor_open函数进行:
1.AF的初始化 sensor_af_init()
2.OTP的读取 otp_module_init()
3.拍照信息的设置 sensor_set_export_Info()
流程图以下：
sensor_open_common流程
sensor_identify扫描流程
LOCAL cmr_int sensor_identify(struct sensor_drv_context *sensor_cxt,
SENSOR_ID_E sensor_id) {
···
ret = sensor_get_match_info(sensor_cxt, sensor_id);
ret = sensor_ic_identify(sensor_cxt, sensor_id);
retValue = sensor_identify_search(sensor_cxt, sensor_id);
return retValue;
}
分析:
1.首先调用sensor_get_match_info去获取咱们本身配置的camera驱动，流程是：
sensor_get_match_info -> sensor_get_module_tab -> back_sensor_infor_tab(以下所示)
vendor/sprd/modules/libcamera/sensor/sensor_cfg.c
这就是为啥咱们驱动工程师添加新的Camea时，都要在这个cfg列表里添加咱们的驱动
const SENSOR_MATCH_T back_sensor_infor_tab[] = {
// gc area
#ifdef GC5005
{MODULE_SUNNY, "gc5005", &g_gc5005_mipi_raw_info, {&dw9714_drv_entry, 0}, NULL},
#endif
#ifdef GC8024
{MODULE_SUNNY, "gc8024", &g_gc8024_mipi_raw_info, {&dw9714_drv_entry, 0}, NULL},
#endif
#ifdef GC030A
{MODULE_SUNNY, "gc030a", &g_gc030a_mipi_raw_info, {NULL, 0}, NULL},
#endif
#ifdef GC2385
{MODULE_SUNNY, "gc2385", &g_gc2385_mipi_raw_info, {NULL, 0}, NULL},
#endif
···
}
2.而后调用sensor_ic_identify去识别ic信息。
识别步骤以下：
1.创建sensor IC驱动结构体
2.配置I2C总线，传感器ID, I2C时钟，从addr, reg addr lenth，数据长度
3.给sensor IC 上电
4.识别sensor IC 的PID和VID
5.删除sensor IC驱动结构体
sensor_ic_identify遍历的流程图以下，
经过 sns_ops->power(sensor_cxt->sns_ic_drv_handle, power_on);调用到sensor驱动的power_on接口，
如ov8856_drv_power_on()
sns_ops->identify(sensor_cxt->sns_ic_drv_handle,SENSOR_ZERO_I2C);调用到sensor驱动的identify接口，
如ov8856_drv_identify()
identify流程
static cmr_int sensor_ic_identify(struct sensor_drv_context *sensor_cxt,
cmr_u32 sensor_id) {
···
//1.创建sensor IC驱动结构体
struct sensor_ic_ops *sns_ops = PNULL;
struct sensor_ic_drv_init_para sns_init_para;
register_info = &sensor_cxt->sensor_register_info;
sns_ops = sensor_cxt->sensor_info_ptr->sns_ops;
sensor_cxt->i2c_addr = mod_cfg_info->major_i2c_addr;
/* 建立 sensor ic handle */
ret = sensor_ic_create(sensor_cxt, sensor_id);
try: /*sensor has backup addr*/
if (sns_ops && sns_ops->identify) {
/*2.初始化 i2c配置*/
hw_drv_cfg.i2c_bus_config = mod_cfg_info->reg_addr_value_bits;
hw_sensor_drv_cfg(sensor_cxt->hw_drv_handle, &hw_drv_cfg);
sensor_i2c_init(sensor_cxt, sensor_id);
//设置i2c地址
hw_sensor_i2c_set_addr(sensor_cxt->hw_drv_handle,
sensor_cxt->i2c_addr);
//设置i2c时钟
hw_sensor_i2c_set_clk(sensor_cxt->hw_drv_handle);
···
//3.给sensor 上电
sensor_power_on(sensor_cxt, SCI_TRUE); /*power on*/
//调用具体的驱动进行identify
ret = sns_ops->identify(sensor_cxt->sns_ic_drv_handle,
SENSOR_ZERO_I2C);
if (SENSOR_SUCCESS == ret) {
/**if the following is SCI_FALSE,that is,now is in identify
*process
* should delete sensor ic handle
**/
if (register_info->is_register[sensor_id] != SCI_TRUE) {
sensor_power_on(sensor_cxt, SCI_FALSE);
sensor_i2c_deinit(sensor_cxt, sensor_id);
sensor_ic_delete(sensor_cxt);
}
sensor_cxt->sensor_list_ptr[sensor_id] =
sensor_cxt->sensor_info_ptr;
register_info->is_register[sensor_id] = SCI_TRUE;
register_info->img_sensor_num++;
} else {
// register_info->is_register[sensor_id] = SCI_FALSE;
sensor_power_on(sensor_cxt, SCI_FALSE);
if ((sensor_cxt->i2c_addr != mod_cfg_info->minor_i2c_addr) &&
mod_cfg_info->minor_i2c_addr != 0x00) {
sensor_cxt->i2c_addr = mod_cfg_info->minor_i2c_addr;
SENSOR_LOGI("use backup i2c address,try again!");
goto try
;
}
SENSOR_LOGI("identify failed!");
//若是identify failed就删除sensor IC信息
sensor_ic_delete(sensor_cxt);
return SENSOR_FAIL;
}
}
return ret;
}
PS: power on 流程 也是咱们驱动工程师常常修改的地方，这里啰嗦几句，以ov8856的上电为例子
这的主要是三路电压，avdd，dvdd，iovdd设置供电，具体参考我以前写的文章: 你应该了解的Camera HW-硬件知识
1.供电部分
camera包含的三路电压为模拟电压（VCAMA），数字电压（VCAMD），IO口电压（VCAMIO）
a) VCAMD 就是 DVDD 数字供电，主要给 ISP 供电
b) VCAM_IO 就是 VDDIO 数字 IO 电源主要给 I2C 部分供电；
c) VCAMA 就是 AVDD 模拟供电，主要给感光区和 ADC 部分供电；
d) VCAM_AF 是对 Camera 自动对焦马达的供电
/*==============================================================================
* Description:
* sensor power on
* please modify this function acording your spec
*============================================================================*/
static cmr_int ov8856_drv_power_on(cmr_handle handle, cmr_u32 power_on) {
SENSOR_IC_CHECK_HANDLE(handle);
···
if (SENSOR_TRUE == power_on) {
//上电流程
//先拉低pnd脚
hw_sensor_power_down(sns_drv_cxt->hw_handle, power_down);
//拉低reset脚
hw_sensor_set_reset_level(sns_drv_cxt->hw_handle, reset_level);
usleep(500);//延迟500微秒，ps这里的延迟要根据规格书来
//设置av电压，主要给感官区和adc部分供电
hw_sensor_set_avdd_val(sns_drv_cxt->hw_handle, avdd_val);
//设置DVDD 电压，主要给ISP供电
hw_sensor_set_dvdd_val(sns_drv_cxt->hw_handle, dvdd_val);
//设置IO电压，IO 电源主要给 I2C 部分供电
hw_sensor_set_iovdd_val(sns_drv_cxt->hw_handle, iovdd_val);
usleep(500);//延迟500微秒
//拉高PND脚
hw_sensor_power_down(sns_drv_cxt->hw_handle, !power_down);
//拉高rst脚
hw_sensor_set_reset_level(sns_drv_cxt->hw_handle, !reset_level);
usleep(500);//延迟500微秒
//设置mclk时钟
hw_sensor_set_mclk(sns_drv_cxt->hw_handle, EX_MCLK);
} else {//下电流程，和上电相反
hw_sensor_set_mclk(sns_drv_cxt->hw_handle, SENSOR_DISABLE_MCLK);
usleep(500);
hw_sensor_set_reset_level(sns_drv_cxt->hw_handle, reset_level);
hw_sensor_power_down(sns_drv_cxt->hw_handle, power_down);
usleep(200);
hw_sensor_set_avdd_val(sns_drv_cxt->hw_handle, SENSOR_AVDD_CLOSED);
hw_sensor_set_dvdd_val(sns_drv_cxt->hw_handle, SENSOR_AVDD_CLOSED);
hw_sensor_set_iovdd_val(sns_drv_cxt->hw_handle, SENSOR_AVDD_CLOSED);
}
SENSOR_LOGI("(1:on, 0:off): %d", power_on);
return SENSOR_SUCCESS;
}
PS2:identify的实现也贴出来,继续啰嗦几句，以ov8856的上电为例子
添加了关键代码注释，很容易理解！
/*==============================================================================
* Description:
* identify sensor id
* please modify this function acording your spec
*============================================================================*/
static cmr_int ov8856_drv_identify(cmr_handle handle, cmr_uint param) {
···
//hw_sensor_read_reg 读取寄存器信息
pid_value = hw_sensor_read_reg(sns_drv_cxt->hw_handle, ov8856_PID_ADDR);
//识别到具体的sendor id
if (ov8856_PID_VALUE == pid_value) {
ver_value = hw_sensor_read_reg(sns_drv_cxt->hw_handle, ov8856_VER_ADDR);
SENSOR_LOGI("Identify: PID = %x, VER = %x", pid_value, ver_value);
if (ov8856_VER_VALUE == ver_value) {
SENSOR_LOGI("this is ov8856 sensor");
//把id信息保存起来
ov8856_drv_init_fps_info(handle);
ret_value = SENSOR_SUCCESS;
} else {
SENSOR_LOGI("Identify this is %x%x sensor", pid_value, ver_value);
}
} else {
SENSOR_LOGE("sensor identify fail, pid_value = %x", pid_value);
}
return ret_value;
}
3.最后若是identify失败，则从新执行上面2个步骤，从新遍历
sensor_identify_search函数实现以下：
LOCAL cmr_u32 sensor_identify_search(struct sensor_drv_context *sensor_cxt,
SENSOR_ID_E sensor_id) {
···
//调用sensor_get_match_info去获取咱们本身配置的camera驱动
module_tab = sensor_get_module_tab(sensor_cxt->is_autotest, sensor_id);
···
//调用sensor_ic_identify去识别ic信息
retValue = sensor_ic_identify(sensor_cxt, sensor_id);
···
return retValue;
}
到此文章的第一部分就写完了，松口气，喝口水，继续写第二部份内容！
3、预览(preview)调用流程
【Hal层】
vendor/sprd/modules/libcamera/hal3_2v1a/SprdCamera3HWI.cpp
int SprdCamera3HWI::openCamera() {
···
//注册ispVideoStartPreview函数
ispvideo_RegCameraFunc(1, ispVideoStartPreview);
···
}
在openCamera函数中，经过这个ispvideo_RegCameraFunc(1, ispVideoStartPreview);注册ispVideoStartPreview
static int ispVideoStartPreview(uint32_t param1, uint32_t param2) {
···
rtn = regularChannel->start(dev->mFrameNum);
···
}
接下来调用regularChannel->start(dev->mFrameNum)往下走
vendor/sprd/modules/libcamera/hal3_2v1/SprdCamera3Channel.cpp
int SprdCamera3RegularChannel::start(uint32_t frame_number) {
int ret = NO_ERROR;
size_t i = 0;
ret = mOEMIf->start(mChannelType, frame_number);
return ret;
}
这里的type :
typedef enum {
CAMERA_CHANNEL_TYPE_DEFAULT, / default /
CAMERA_CHANNEL_TYPE_REGULAR, / regular channel /
CAMERA_CHANNEL_TYPE_PICTURE, / picture channel/
CAMERA_CHANNEL_TYPE_RAW_CALLBACK, /YUV888 callback/
CAMERA_CHANNEL_TYPE_MAX,
} camera_channel_type_t;
接着调用 ret = mOEMIf->start(mChannelType, frame_number);
vendor/sprd/modules/libcamera/hal3_2v1/SprdCamera3OEMIf.cpp
int SprdCamera3OEMIf::start(camera_channel_type_t channel_type,
uint32_t frame_number) {
···
switch (channel_type) {
case CAMERA_CHANNEL_TYPE_REGULAR: {
···
ret = startPreviewInternal();//这里继续跟进去
break;
}
//如下是拍照部分，咱们下个部分在进行分析
case CAMERA_CHANNEL_TYPE_PICTURE: {
if (mTakePictureMode == SNAPSHOT_NO_ZSL_MODE ||
ret = takePicture();
}
else if (mTakePictureMode == SNAPSHOT_ZSL_MODE) {
ret = zslTakePicture();
} else if (mTakePictureMode == SNAPSHOT_VIDEO_MODE) {
ret = VideoTakePicture();
}
break;
}
default:
break;
}
···
return ret;
}
若是类型为CAMERA_CHANNEL_TYPE_REGULAR，则调用：
ret = startPreviewInternal();//这里继续跟进去
若是类型为CAMERA_CHANNEL_TYPE_PICTURE，则调用拍照相关：
ret = takePicture();
ret = zslTakePicture();
ret = VideoTakePicture();
int SprdCamera3OEMIf::startPreviewInternal() {
···
//preview的时候，设置照片的thumbnail size(压缩后的大小)和camera app的大小一致
chooseDefaultThumbnailSize(&jpeg_thumb_size.width, &jpeg_thumb_size.height);
···
ret = mHalOem->ops->camera_start_preview(mCameraHandle, mCaptureMode);
···
}
mHalOem->ops->camera_start_preview(mCameraHandle, mCaptureMode);方法的实如今SprdOEMCamera.c里
vendor/sprd/modules/libcamera/oem2v1/src/SprdOEMCamera.c
cmr_int camera_start_preview(cmr_handle camera_handle,
enum takepicture_mode mode) {
···
ret = camera_local_start_preview(camera_handle, mode, CAMERA_PREVIEW);
···
return ret;
}
【OEM层】
该函数很简单，就继续调用camera_local_start_preview函数
vendor/sprd/modules/libcamera/oem2v1/src/cmr_oem.c
cmr_int camera_local_start_preview(cmr_handle oem_handle,
enum takepicture_mode mode,
cmr_uint is_snapshot) {
//设置preview的参数
ret = camera_set_preview_param(oem_handle, mode, is_snapshot);
//继续cmr_preview_start
ret = cmr_preview_start(prev_cxt->preview_handle, cxt->camera_id);
···
return ret;
}
该函数设置preview的参数信息，而后继续调用cmr_preview_start方法
vendor/sprd/modules/libcamera/oem2v1/src/cmr_preview.c
cmr_int cmr_preview_start(cmr_handle preview_handle, cmr_u32 camera_id) {
···
message.msg_type = PREV_EVT_ASSIST_START;//设置msg的type类型PREV_EVT_ASSIST_START
message.sync_flag = CMR_MSG_SYNC_PROCESSED;//设置msg的flag
//发送msg消息
ret = cmr_thread_msg_send(handle->thread_cxt.assist_thread_handle, &message);
···
message.msg_type = PREV_EVT_START;//设置msg的type类型PREV_EVT_START
message.sync_flag = CMR_MSG_SYNC_PROCESSED;//设置msg的flag
message.data = (void *)((unsigned long)camera_id);
//发送了msg消息
ret = cmr_thread_msg_send(handle->thread_cxt.thread_handle, &message);
···
return ret;
}
这里主要调用cmr_thread_msg_send发送两条msg消息，
第一条msg=消息
assist_thread_handle=prev_assist_thread_proc
该handle的建立：
在prev_create_thread(struct prev_handle *handle)调用
ret = cmr_thread_create(&handle>thread_cxt.assist_thread_handle,PREV_MSG_QUEUE_SIZE, prev_assist_thread_proc, (void *)handle);
cmr_int prev_assist_thread_proc(struct cmr_msg *message, void *p_data) {
···
msg_type = (cmr_u32)message->msg_type;//得到msg_tyoe
//根据msg_type进行操做
switch (msg_type) {
case PREV_EVT_ASSIST_START:
handle->frame_active = 1;
break;
···
case PREV_EVT_ASSIST_STOP:
handle->frame_active = 0;
break;
···
return ret;
}
当msg_type=PREV_EVT_ASSIST_START:
仅仅操做handle->frame_active = 1;
第二条msg=消息
thread_cxt.thread_handle=prev_thread_proc
cmr_int prev_thread_proc(struct cmr_msg *message, void *p_data) {
···
switch (msg_type) {
···
case PREV_EVT_START:
camera_id = (cmr_u32)((unsigned long)message->data);
prev_recovery_reset(handle, camera_id);
ret = prev_start(handle, camera_id, 0, 0);
/*Notify preview started*/
cb_data_info.cb_type = PREVIEW_EXIT_CB_PREPARE;
cb_data_info.func_type = PREVIEW_FUNC_START_PREVIEW;
cb_data_info.frame_data = NULL;
prev_cb_start(handle, &cb_data_info);
break;
···
}
分析：
1.ret = prev_start(handle, camera_id, 0, 0)调用流程以下：
ret = handle->ops.channel_start(···);【cmr_preview.c】
->cmr_int camera_channel_start(···);【cmr_oem.c】
->cmr_int cmr_grab_cap_start(···)【cmr_grab.c】
->ret = ioctl(p_grab->fd, SPRD_IMG_IO_SET_CAP_SKIP_NUM, &num);【cmr_grab.c】
【kernel层】
经过ioctl的方式调用kernel层的方法
通过以上一系列复杂流程，后看到cmr_grab_cap_start()调入到kernel目录执行打开DCAM,cmr_grab_cap_start经过ioctl的方式调用kernel层的方法。
cmr_int cmr_grab_cap_start(cmr_handle grab_handle, cmr_u32 skip_num) {
···
ret = ioctl(p_grab->fd, SPRD_IMG_IO_SET_CAP_SKIP_NUM, &num);
ATRACE_BEGIN("dcam_stream_on");
ret = ioctl(p_grab->fd, SPRD_IMG_IO_STREAM_ON, &stream_on);
···
return ret;
}
kernel/drivers/misc/sprd_camera/dcam/dcam_if_r4p0/dcam_ioctrl.c
{SPRD_IMG_IO_STREAM_ON, dcamio_stream_on},
static int dcamio_stream_on(struct camera_file *camerafile,
unsigned long arg,
unsigned int cmd)
{
···
ret = sprd_img_get_dcam_dev(camerafile, &dev, &info);
ret = sprd_camera_stream_on(camerafile);
···
return ret;
}
2.prev_cb_start(handle, &cb_data_info)调用流程以下：
prev_cb_start(handle, &cb_data_info)//cmr_preview.c
->ret = cmr_thread_msg_send(···);//cmr_preview.c
//message.msg_type = PREV_EVT_CB_START;cb_thread_handle = prev_cb_thread_proc
->ret = handle->oem_cb(···)//cmr_preview.c
//handle->oem_cb = init_param_ptr->oem_cb=camera_preview_cb;
->ret = cmr_thread_msg_send(···);// oem2v1/src/cmr_oem.c
//message.sub_msg_type = oem_cb_type;
//prev_cb_thr_handle = camera_preview_cb_thread_proc
->callback(···);
vendor/sprd/modules/libcamera/oem2v1/src/cmr_oem.c
cmr_int camera_preview_cb_thread_proc(struct cmr_msg *message, void *data) {
···
callback = cxt->camera_cb;
callback(message->sub_msg_type, cxt->client_data,
message->msg_type, message->data);
···
return ret;
}
这里callback 为 cxt->camera_cb;具体实如今SprdCamera3OEMIf::camera_cb(···);
vendor/sprd/modules/libcamera/hal3_2v1/SprdCamera3OEMIf.cpp
void SprdCamera3OEMIf::camera_cb(enum camera_cb_type cb,
const void *client_data,
enum camera_func_type func, void *parm4) {
···
switch (func) {
case CAMERA_FUNC_START_PREVIEW:
obj->HandleStartPreview(cb, parm4);
break;
···
这里在oem_func = CAMERA_FUNC_START_PREVIEW;所以继续调用HandleStartPreview(cb, parm4);
void SprdCamera3OEMIf::HandleStartPreview(enum camera_cb_type cb, void *parm4) {
···
receivePreviewFrame((struct camera_frame_type *)parm4);
···
}
这里是调用receivePreviewFrame接收frame data
void SprdCamera3OEMIf::receivePreviewFrame(struct camera_frame_type *frame) {
···
//接收frame data
channel->getStream(CAMERA_STREAM_TYPE_PREVIEW, &pre_stream);
channel->getStream(CAMERA_STREAM_TYPE_VIDEO, &rec_stream);
channel->getStream(CAMERA_STREAM_TYPE_CALLBACK, &callback_stream);
HAL_LOGV("pre_stream %p, rec_stream %p, callback_stream %p", pre_stream,
rec_stream, callback_stream);
//美颜
#ifdef CONFIG_FACE_BEAUTY
int sx, sy, ex, ey, angle, pose;
struct face_beauty_levels beautyLevels;
beautyLevels.blemishLevel =
(unsigned char)sprddefInfo.perfect_skin_level[0];
beautyLevels.smoothLevel = (unsigned char)sprddefInfo.perfect_skin_level[1];
beautyLevels.skinColor = (unsigned char)sprddefInfo.perfect_skin_level[2];
beautyLevels.skinLevel = (unsigned char)sprddefInfo.perfect_skin_level[3];
beautyLevels.brightLevel = (unsigned char)sprddefInfo.perfect_skin_level[4];
beautyLevels.lipColor = (unsigned char)sprddefInfo.perfect_skin_level[5];
beautyLevels.lipLevel = (unsigned char)sprddefInfo.perfect_skin_level[6];
beautyLevels.slimLevel = (unsigned char)sprddefInfo.perfect_skin_level[7];
beautyLevels.largeLevel = (unsigned char)sprddefInfo.perfect_skin_level[8];
#endif
···
}
这个函数实现很复杂，主要用来recevie Frame data here , 以及美颜等，具体细节之后分析。
4、拍照(snapshot)调用流程
【Hal层】
咱们直接从SprdCamera3OEMIf::start开始分析，怎么调用到这个函数的，前面已经分析过了，就不在赘述！
vendor/sprd/modules/libcamera/hal3_2v1/SprdCamera3OEMIf.cpp
int SprdCamera3OEMIf::start(camera_channel_type_t channel_type,
uint32_t frame_number) {
···
switch (channel_type) {
···
case CAMERA_CHANNEL_TYPE_PICTURE: {
if (···)
setCamPreformaceScene(CAM_CAPTURE_S_LEVEL_NH);
}
if (mTakePictureMode == SNAPSHOT_NO_ZSL_MODE ||
mTakePictureMode == SNAPSHOT_ONLY_MODE)
···
ret = takePicture();
···
else if (mTakePictureMode == SNAPSHOT_ZSL_MODE) {
mVideoSnapshotFrameNum = frame_number;
···
ret = zslTakePicture();
···
} else if (mTakePictureMode == SNAPSHOT_VIDEO_MODE) {
mVideoSnapshotFrameNum = frame_number;
ret = VideoTakePicture();
}
break;
}
···
}
···
}
分析：首先channel_type=CAMERA_CHANNEL_TYPE_PICTURE，而后进行如下动做：
1.setCamPreformaceScene(CAM_CAPTURE_S_LEVEL_NH);设定Camera的场景，场景类型以下
typedef enum CAMERA_PERFORMACE_SCENE {
CAM_OPEN_S,
CAM_OPEN_E_LEVEL_H, // DFS:veryhigh
CAM_OPEN_E_LEVEL_N, // DFS:normal
CAM_OPEN_E_LEVEL_L, // DFS:low
CAM_PREVIEW_S_LEVEL_H, // powerhint:performance
CAM_PREVIEW_S_LEVEL_N, // powerhint:normal
CAM_PREVIEW_S_LEVEL_L, // powerhint:low
CAM_CAPTURE_S_LEVEL_HH, // powerhint:performance DFS:veryhigh
CAM_CAPTURE_S_LEVEL_HN, // powerhint:performance DFS:normal
CAM_CAPTURE_S_LEVEL_NH, // powerhint:normal DFS:veryhigh
CAM_CAPTURE_S_LEVEL_NN, // powerhint:normal DFS:normal
CAM_CAPTURE_E_LEVEL_NH, // powerhint:normal DFS:veryhigh
CAM_CAPTURE_E_LEVEL_NN, // powerhint:normal DFS:normal
CAM_CAPTURE_E_LEVEL_NL, // powerhint:normal DFS:low
CAM_CAPTURE_E_LEVEL_LN, // powerhint:low DFS:normal
CAM_CAPTURE_E_LEVEL_LL, // powerhint:low DFS:low
CAM_CAPTURE_E_LEVEL_LH, // powerhint:low DFS:veryhigh
CAM_FLUSH_S,
CAM_FLUSH_E,
CAM_EXIT_S,
CAM_EXIT_E,
} sys_performance_camera_scene;
2.根据mTakePictureMode调用不一样的拍照方法
- 第一种：普通拍照模式
mTakePictureMode =SNAPSHOT_NO_ZSL_MODE 或者 SNAPSHOT_ONLY_MODE
ret = takePicture(); - 第二种：零延迟拍照(预览画面是啥，拍出来的就是啥，所见即所得)
mTakePictureMode == SNAPSHOT_ZSL_MODE
ret = zslTakePicture(); - 第三种：视频模式
mTakePictureMode == SNAPSHOT_VIDEO_MODE
ret = VideoTakePicture();
有3条分支，这里咱们选择普通的拍照模式分支继续分析。
int SprdCamera3OEMIf::takePicture() {
···
mHalOem->ops->camera_take_picture(mCameraHandle, mCaptureMode)
···
}
其实takePicture函数有不少操做，好比：相机是否已经preview，没有的话，先进行preview，其次，相机是否正在capturing(截屏)，若是是的话，等待，直到capturing结束等等。最后调用
mHalOem->ops->camera_take_picture(mCameraHandle, mCaptureMode)来调用到oem层。
OEM层(展讯本身封装的一层，Hal层和驱动层沟通的中间桥梁)
vendor/sprd/modules/libcamera/oem2v1/src/SprdOEMCamera.c
cmr_int camera_take_picture(cmr_handle camera_handle,
enum takepicture_mode cap_mode) {
···
ret = camera_local_start_snapshot(camera_handle, cap_mode, CAMERA_SNAPSHOT);
if (ret) {
CMR_LOGE("failed to start snapshot %ld", ret);
}
···
}
分析：这个函很简单，就直接调用camera_local_start_snapshot进行拍照动做
vendor/sprd/modules/libcamera/oem2v1/src/cmr_oem.c
cmr_int camera_local_set_cap_size(cmr_handle oem_handle,
cmr_u32 is_reprocessing, cmr_u32 camera_id,
cmr_u32 width, cmr_u32 height) {
//1
ret = cmr_snapshot_post_proc(cxt->snp_cxt.snapshot_handle, &snp_param);
//2
ret = camera_local_start_capture(oem_handle);
//3
ret = cmr_snapshot_receive_data(cxt->snp_cxt.snapshot_handle,
SNAPSHOT_EVT_CHANNEL_DONE,
(void *)&frame);
}
分析：该函数主要作了如下事情：
1.调用cmr_snapshot_post_proc()函数发送一条msg消息
2.调用camera_local_start_capture()函数继续拍照流程
3.调用cmr_snapshot_receive_data()函数receive拍照的数据
先来看
1.调用cmr_snapshot_post_proc()函数发送一条msg消息
vendor/sprd/modules/libcamera/oem2v1/src/cmr_snapshot.c
cmr_int cmr_snapshot_post_proc(cmr_handle snapshot_handle,
struct snapshot_param *param_ptr) {
···
message.msg_type = SNP_EVT_START_PROC;
message.sync_flag = CMR_MSG_SYNC_PROCESSED;
message.alloc_flag = 0;
message.data = param_ptr;
ret = cmr_thread_msg_send(cxt->thread_cxt.main_thr_handle, &message);
···
}
消息类型： message.msg_type = SNP_EVT_START_PROC;
线程处理函数为：snp_main_thread_proc。
咱们来看这个处理函数：
cmr_int snp_main_thread_proc(struct cmr_msg *message, void *p_data) {
···
switch (message->msg_type) {
···
case SNP_EVT_START_PROC:
ret = snp_set_post_proc_param(snp_handle,
(struct snapshot_param *)message->data);
break;
···
}
···
}
分析：直接调用snp_set_post_proc_param函数
cmr_int snp_set_post_proc_param(cmr_handle snp_handle,
struct snapshot_param *param_ptr) {
···
ret = cxt->ops.get_sensor_info(cxt->oem_handle, cxt->req_param.camera_id,
&cxt->sensor_info);
ret = snp_set_jpeg_dec_param(snp_handle);
ret = snp_set_isp_proc_param(snp_handle);
ret = snp_set_channel_out_param(snp_handle);
ret = snp_set_hdr_param(snp_handle);
snp_get_is_scaling(snp_handle, is_normal_cap);
ret = snp_set_rot_param(snp_handle);
ret = snp_set_jpeg_enc_param(snp_handle);
ret = snp_set_jpeg_exif_param(snp_handle);
···
}
分析：设置各类参数。
2.调用camera_local_start_capture()函数继续拍照流程
vendor/sprd/modules/libcamera/oem2v1/src/cmr_oem.c
cmr_int camera_local_start_capture(cmr_handle oem_handle) {
//设置拍照的时候是否须要闪光灯
camera_local_snapshot_is_need_flash(oem_handle, cxt->camera_id,
&flash_status);
//继续调用cmr_grab_start_capture拍照
ret = cmr_grab_start_capture(cxt->grab_cxt.grab_handle, capture_param);
}
这里继续调用cmr_grab_start_capture拍照。
vendor/sprd/modules/libcamera/oem2v1/src/cmr_grab.c
cmr_int cmr_grab_start_capture(cmr_handle grab_handle,
struct sprd_img_capture_param capture_param) {
struct cmr_grab *p_grab;
p_grab = (struct cmr_grab *)grab_handle;
ret = ioctl(p_grab->fd, SPRD_IMG_IO_START_CAPTURE, &capture_param);
···
}
从这里开始，就调用到咱们驱动层了，经过ioctl的接口调用驱动的函数。那么经过SPRD_IMG_IO_START_CAPTURE这个cmd调用的时哪一个函数呢？
【kernel层】
kernel/drivers/misc/sprd_camera/dcam/dcam_if_r4p0/
static struct dcam_io_ctrl_fun s_cam_io_ctrl_fun_tab[] = {
···
{SPRD_IMG_IO_START_CAPTURE, dcamio_start_capture},
···
}
所以，能够看出调用的时dcamio_start_capture函数，好吧，咱们就跟到kernel层一探究竟！！！
kernel/drivers/misc/sprd_camera/dcam/dcam_if_r4p0/dcam_ioctrl.c
static int dcamio_start_capture(struct camera_file *camerafile,
unsigned long arg,
unsigned int cmd)
{
int ret = 0;
unsigned int cap_flag = 0;
struct camera_dev *dev = NULL;
struct camera_info *info = NULL;
struct camera_group *group = NULL;
//获取设备信息
ret = sprd_img_get_dcam_dev(camerafile, &dev, &info);
if (ret) {
pr_err("fail to get dcam dev\n");
goto exit;
}
group = camerafile->grp;
//从用户空间得到数据，拷贝到cap_flag变量中
ret = copy_from_user(&cap_flag, (void __user *) arg,
sizeof(unsigned int));
if (ret) {
pr_err("fail to get user info\n");
ret = -EFAULT;
goto exit;
}
if (dev->cap_flag == DCAM_CAPTURE_STOP) {
dev->cap_flag = DCAM_CAPTURE_START;
if (dev->dcam_cxt.need_isp_tool)
cap_flag = DCAM_CAPTURE_NONE;
pr_info("start capture, cap_flag %d\n", cap_flag);
//调用该函数进行拍照动做
ret = sprd_isp_start_pipeline_full(dev->isp_dev_handle,
cap_flag);
if (ret) {
pr_err("fail to start offline\n");
goto exit;
}
}
//拍照完成
pr_info("start capture done\n");
exit:
return ret;
}
注释添加的很清晰了，这里简单说一下
调用sprd_isp_start_pipeline_full动做去执行拍照，最后的数据会保存在p_offline_frame中！【struct camera_frame *p_offline_frame = NULL，p_offline_frame是一个指针】
**p_offline_frame = &dev->offline_frame[ISP_OFF_BUF_FULL];**
**memcpy(p_offline_frame, &frame, sizeof(struct camera_frame));**
**complete(&dev->offline_full_thread_com);**
最后经过complete唤醒线程，让线程去接受数据。
PS:【complete是完成量的概念，用于保护共享数据，防止竞态，而且告诉另外一个休眠的线程，说我边完事了，你醒醒，继续干你的活去。具体能够参考LDD这本书或者自行百度】
最后咱们简单分析一下是如何收取数据的
3.调用cmr_snapshot_receive_data()函数receive拍照的数据
vendor/sprd/modules/libcamera/oem2v1/src/cmr_snapshot.c
cmr_int cmr_snapshot_receive_data(cmr_handle snapshot_handle, cmr_int evt,
void *data) {
···
switch (evt) {//normol拍照模式
case SNAPSHOT_EVT_CHANNEL_DONE:
malloc_len = sizeof(struct frm_info);
CMR_LOGD("video %d zsl %d yaddr_vir 0x%x",
cxt->req_param.is_video_snapshot,
cxt->req_param.is_zsl_snapshot, frame_info_ptr->yaddr_vir);
buffer_id = snp_get_buffer_id(snapshot_handle, data);
buffer_id += frame_info_ptr->base;
snp_evt = SNP_EVT_CHANNEL_DONE;
if (1 == cxt->req_param.is_video_snapshot ||
1 == cxt->req_param.is_zsl_snapshot) {
flag = 1;
width = cxt->req_param.post_proc_setting.chn_out_frm[0].size.width;
height =
cxt->req_param.post_proc_setting.chn_out_frm[0].size.height;
act_width = cxt->req_param.post_proc_setting.actual_snp_size.width;
act_height =
cxt->req_param.post_proc_setting.actual_snp_size.height;
//memcpy指的是c和c++使用的内存拷贝函数，从kernel中经过地址拷贝数据到oem层
memcpy(&chn_data, data, sizeof(struct frm_info));
chn_data.base = CMR_CAP0_ID_BASE;
chn_data.frame_id = CMR_CAP0_ID_BASE;
if (1 == cxt->req_param.is_zsl_snapshot) {
chn_data.base = CMR_CAP1_ID_BASE;
chn_data.frame_id = CMR_CAP1_ID_BASE;
}
}
if (1 == cxt->req_param.is_video_snapshot) {//视频模式
···
cmr_copy((void *)dst_vir, (void *)src_vir, width * height / 2);
cmr_snapshot_memory_flush(
cxt, &(cxt->req_param.post_proc_setting.chn_out_frm[0]));
···
} else if (1 == cxt->req_param.is_zsl_snapshot) {//零延迟拍照模式
···
cmr_copy((void *)dst_vir, (void *)src_vir, width * height / 2);
cmr_snapshot_memory_flush(
cxt, &(cxt->req_param.post_proc_setting.chn_out_frm[0]));
···
}
break;
···
}
···
}
拍完照片后，咱们会受到一个msg消息，type=SNAPSHOT_EVT_CHANNEL_DONE，表示拍照完成！
调用memcpy(&chn_data, data, sizeof(struct frm_info));从kernel获取数据，还记得kernel中是吧数据保存在
struct camera_frame *p_offline_frame 指针中，咱们经过地址把数据拷贝出来！
即memcpy(&chn_data, data, sizeof(struct frm_info));！