linux驱动由浅入深系列：高通sensor架构实例分析之二(驱动代码结构)

本系列导航：

linux驱动由浅入深系列：高通sensor架构实例分析之一(整体概览+AP侧代码分析)

linux驱动由浅入深系列：高通sensor架构实例分析之二(adsp驱动代码结构)
Linux驱动由浅入深系列：高通sensor架构实例分析之三(adsp上报数据详解、校准流程详解)

上一篇文章中我们了解了高通sensor的整体架构及对AP侧的代码进行了分析，这篇文章我们详细分析一下aDSP侧的代码结构。

 

sensor数据流关键代码概览

下图是sensor数据流程中的关键代码部分:

实现sensor驱动最重要的一个结构体

结合上一篇的测试代码，可以清楚的看到高通sensor的数据处理流程。图中7位置指示了每个基于ADSP架构的传感器需要实现的接口如下：

typedef struct{    /**      * @brief Initializes the driver and sets up devices.     *       * Allocates a handle to a driver instance, opens a communication port to      * associated devices, configures the driver and devices, and places      * the devices in the default power state. Returns the instance handle along      * with a list of supported sensors. This function will be called at init      * time.     *       * @param[out] dd_handle_ptr  Pointer that this function must malloc and      *                            populate. This is a handle to the driver     *                            instance that will be passed in to all other     *                            functions. NB: Do not use @a memhandler to     *                            allocate this memory.     * @param[in]  smgr_handle    Handle used to identify this driver when it      *                            calls into Sensors Manager functions.     * @param[in]  nv_params      NV parameters retrieved for the driver.     * @param[in]  device_info    Access info for physical devices controlled by      *                            this driver. Used to configure the bus     *                            and talk to the devices.     * @param[in]  num_devices    Number of elements in @a device_info.      * @param[in]  memhandler     Memory handler used to dynamically allocate      *                            output parameters, if applicable. NB: Do not     *                            use memhandler to allocate memory for     *                            @a dd_handle_ptr.     * @param[in/out] sensors     List of supported sensors, allocated,      *                            populated, and returned by this function.     * @param[in/out] num_sensors Number of elements in @a sensors.     *     * @return Success if @a dd_handle_ptr was allocated and the driver was      *         configured properly. Otherwise a specific error code is returned.     */    sns_ddf_status_e (*init)(        sns_ddf_handle_t*        dd_handle_ptr,        sns_ddf_handle_t         smgr_handle,        sns_ddf_nv_params_s*     nv_params,        sns_ddf_device_access_s  device_info[],        uint32_t                 num_devices,        sns_ddf_memhandler_s*    memhandler,        sns_ddf_sensor_e**       sensors,        uint32_t*                num_sensors);            /**      * @brief Retrieves a single set of sensor data.     *       * Requests a single sample of sensor data from each of the specified     * sensors. Data is returned in one of two ways: (1) immediately after being      * read from the sensor, in which case data is populated in the same order      * it was requested, or (2) in cases where the sensor requires several steps      * to be read, this function will return with the status SNS_DDF_PENDING,      * and provide the data asynchronously via @a sns_ddf_smgr_data_notify()      * when it is ready. Note that @a sns_ddf_smgr_data_notify() must be called      * even in the event of an error in order to report a failed status. An      * asynchronous notification is also expected in the case of mixed data      * (i.e. synchronous and asynchronous).     *      * @note In the case where multiple sensors are requested, the driver must      *       attempt to collect data from all requested sensors, meaning that     *       the time it takes to execute this function will be determined by     *       the number of sensors sampled, and their various delays. Drivers     *       must never return partial responses. If a sensor has failed or     *       isn't available, @a sns_ddf_sensor_data_s.status must be used to     *       reflect this status.      *      * @param[in]  dd_handle    Handle to a driver instance.     * @param[in]  sensors      List of sensors for which data is requested.     * @param[in]  num_sensors  Number of elements in @a sensors.     * @param[in]  memhandler   Memory handler used to dynamically allocate      *                          output parameters, if applicable.     * @param[out] data         Sampled sensor data. The number of elements must      *                          match @a num_sensors.     *     * @return SNS_DDF_SUCCESS if data was populated successfully. If any of the      *         sensors queried are to be read asynchronously SNS_DDF_PENDING is     *         returned and data is via @a sns_ddf_smgr_data_notify() when     *         available. Otherwise a specific error code is returned.     *       * @see sns_ddf_data_notify()     */    sns_ddf_status_e (*get_data)(        sns_ddf_handle_t         dd_handle,        sns_ddf_sensor_e         sensors[],        uint32_t                 num_sensors,        sns_ddf_memhandler_s*    memhandler,        sns_ddf_sensor_data_s**  data);    /**     * @brief Sets a sensor attribute to a specific value.     *     * @param[in] dd_handle  Handle to a driver instance.     * @param[in] sensor     Sensor for which this attribute is to be set. When      *                       addressing an attribute that refers to the driver     *                       this value is set to SNS_DDF_SENSOR__ALL.     * @param[in] attrib     Attribute to be set.     * @param[in] value      Value to set this attribute.     *     * @return Success if the value of the attribute was set properly. Otherwise      *         a specific error code is returned.     */    sns_ddf_status_e (*set_attrib)(        sns_ddf_handle_t     dd_handle,        sns_ddf_sensor_e     sensor,        sns_ddf_attribute_e  attrib,        void*                value);    /**     * @brief Retrieves the value of an attribute for a sensor.     *      * @param[in]  dd_handle   Handle to a driver instance.     * @param[in]  sensor      Sensor whose attribute is to be retrieved. When      *                         addressing an attribute that refers to the driver     *                         this value is set to SNS_DDF_SENSOR__ALL.     * @param[in]  attrib      Attribute to be retrieved.     * @param[in]  memhandler  Memory handler used to dynamically allocate      *                         output parameters, if applicable.     * @param[out] value       Pointer that this function will allocate or set      *                         to the attribute's value.     * @param[out] num_elems   Number of elements in @a value.     *       * @return Success if the attribute was retrieved and the buffer was      *         populated. Otherwise a specific error code is returned.     */    sns_ddf_status_e (*get_attrib)(        sns_ddf_handle_t       dd_handle,        sns_ddf_sensor_e       sensor,        sns_ddf_attribute_e    attrib,        sns_ddf_memhandler_s*  memhandler,        void**                 value,        uint32_t*              num_elems);         /**    * @brief Called when the timer set by this driver has expired. This must be     *        the callback function submitted when initializing a timer.    *      * @note This will be called within the context of the Sensors Manager task.    *     * @param[in] dd_handle  Handle to a driver instance.    * @param[in] arg        The argument submitted when the timer was set.     *     * @see sns_ddf_set_timer()     */    void (*handle_timer)(sns_ddf_handle_t dd_handle, void* arg);   /**     * @brief Called in response to an interrupt for this driver.    *      * @note This function will be called within the context of the SMGR task,     *       *not* the ISR.     *    * @param[in] dd_handle  Handle to a driver instance.     * @param[in] gpio_num   GPIO number that triggered this interrupt.    * @param[in] timestamp  Time at which interrupt happened.    */    void (*handle_irq)(        sns_ddf_handle_t  dd_handle,        uint32_t          gpio_num,        sns_ddf_time_t    timestamp);   /**    * @brief Resets the driver and device so they return to the state they were     *        in after init() was called.    *    * @param[in] dd_handle  Handle to a driver instance.    *     * @return Success if the driver was able to reset its state and the device.    *         Otherwise a specific error code is returned.     */    sns_ddf_status_e (*reset)(sns_ddf_handle_t dd_handle);    /**     * @brief Runs a factory test case.     *       * Tests may include embedded hardware tests in cases where the sensor      * supports it, as well as driver based sensor tests. This is generally run      * in a factory setting and must not be called while a device is streaming      * data.      *       * @param[in]  dd_handle  Handle to a driver instance.      * @param[in]  sensor     Sensor on which to run the test.      * @param[in]  test       Test case to run.      * @param[out] err        Optional driver-specific error code.     *       * @return One of the following error codes:     *     SNS_DDF_SUCCESS        - Test passed.     *     SNS_DDF_PENDING        - Test result will be sent as an event.     *     SNS_DDF_EDEVICE_BUSY   - Device is busy streaming, cannot run test.     *     SNS_DDF_EINVALID_TEST  - Test is not defined for this sensor.     *     SNS_DDF_EINVALID_PARAM - One of the parameters is invalid.     *     SNS_DDF_EFAIL          - Unknown error occurred.     */    sns_ddf_status_e (*run_test)(        sns_ddf_handle_t  dd_handle,        sns_ddf_sensor_e  sensor,        sns_ddf_test_e    test,        uint32_t*         err);    /**     * @brief Begins device-scheduled sampling and enables notification via Data      *        Ready Interrupts (DRI).     *     * The driver commands the device to begin sampling at the configured      * ODR (@a SNS_DDF_ATTRIB_ODR) and enables DRI. When data is ready, the      * driver's handle_irq() function is called and the driver notifies      * SMGR of the event via @a sns_ddf_smgr_notify_event() and @a      * SNS_DDF_EVENT_DATAREADY.      *       * @param[in] handle  Handle to the driver's instance.     * @param[in] sensor  Sensor to be sampled.     * @param[in] enable  True to enable or false to disable data stream.     *      * @return SNS_DDF_SUCCESS if sensor was successfully configured and      *         internal sampling has commenced or ceased. Otherwise an     *         appropriate error code.     */    sns_ddf_status_e (*enable_sched_data)(        sns_ddf_handle_t  handle,        sns_ddf_sensor_e  sensor,        bool              enable);    /**     * @brief Probes for the device with a given configuration.     *     * This commands the driver to look for the device with the specified     * configuration (ie, I2C address/bus defined in the sns_ddf_device_access_s     * struct.     *     * @param[in]  dev_info    Access info for physical devices controlled by      *                         this driver. Used to determine if the device is     *                         physically present.     * @param[in]  memhandler  Memory handler used to dynamically allocate      *                         output parameters, if applicable.     * @param[out] num_sensors Number of sensors supported. 0 if none.     * @param[out] sensor_type Array of sensor types supported, with num_sensor     *                         elements. Allocated by this function.     *     * @return SNS_DDF_SUCCESS if the part was probed function completed, even     *         if no device was found (in which case num_sensors will be set to     *         0).     */    sns_ddf_status_e(*probe)(        sns_ddf_device_access_s* device_info,        sns_ddf_memhandler_s*    memhandler,        uint32_t*                num_sensors,        sns_ddf_sensor_e**       sensors );            /**     * @brief Retrieves a set of sensor data. Asynchronous API     *     * Requests sample of sensor data from the specified sensor.     *     * @note If a sensor has failed or     *       isn't available, @a sns_ddf_sensor_data_s.status must be used to     *       reflect this status.     *     * @param[in]  dd_handle    Handle to a driver instance.     * @param[in]  sensor      sensor for which data is requested.     *     * @param[in]  num_samples  number of samples to retrieve as available. Drain the FIFO if value is set to Zero.     * @param[in]  trigger now  trigger notify fifo data now or     *       later when trigger_now is set to true.     *     *     * @return SNS_DDF_SUCCESS if data was populated successfully.     *         via sns_ddf_smgr_data_notify() or if trigger_now is     *         set to false; Otherwise a specific error code is     *         returned.     *     * @see sns_ddf_data_notify_data() as this will be used to report the data.     */    sns_ddf_status_e (*trigger_fifo_data)(        sns_ddf_handle_t         dd_handle,        sns_ddf_sensor_e         sensor,        uint16_t                 num_samples,        bool                     trigger_now);    /**     * @brief Delivers a Driver Access Framework message to the driver.     *        Asynchronous/Synchronous API.     *     * @detail     *     * @param[in]  dd_handle     Handle to a driver instance.     * @param[in]  req_id        Request identifier.     * @param[in]  req_msg       Request message in the opaque payload. If no     *                           payload is supplied, then this pointer will be     *                           null.     * @param[in]  req_size      Number of bytes in @req_msg. If req_msg is empty,     *                           this value must be 0.     * @param[in]  memhandler    Memory handler used to dynamically allocate     *                           output parameters, if applicable.     * @param[out] resp_msg      Pointer to the output message pointer. The output     *                           message must be allocated first using @memhandler.     * @param[out] resp_size     Pointer to number of bytes in @resp_msg. If there     *                           is no DAF response message for the request, then     *                           this must be 0 to show that the DAF response is     *                           not present. Response messages are limited in     *                           size to @SNS_SMGR_MAX_DAF_MESSAGE_SIZE_V01 bytes.     *                           Any response message larger than     *                           @SNS_SMGR_MAX_DAF_MESSAGE_SIZE_V01 bytes will be     *                           truncated.     * @param[in]  trans_id_ptr  Pointer to the optional transaction identifier.                                 This will be null if a transaction ID was not                                 provided.     * @param[in]  conn_handle   The connection handle for the request message.     *                           This value must be saved if the particular request     *                           is expected to generate indications. Upon     *                           notifying the SMGR of an indication, this value     *                           must be provided to the SMGR.     *     * @return Success if the message was retrieved and the buffer was correctly     *         populated. Otherwise a specific error code is returned.     */     sns_ddf_status_e (*process_daf_req)(         sns_ddf_handle_t       dd_handle,         uint32_t               req_id,         const void*            req_msg,         uint32_t               req_size,         sns_ddf_memhandler_s*  memhandler,         void**                 resp_msg,         uint32_t*              resp_size,         const uint8_t*         trans_id_ptr,         void*                  conn_handle);    /**     * @brief Cancels all of the driver's current Driver Access Framework     *        asynchronous transactions for the provided connection handle.     *     * @note This does not have to cancel a response message in the process of     *       being created.     *       This function does not have to be implemented for drivers that do     *       not support or implement any asynchronous messages (these messages     *       require the usage of sns_ddf_smgr_notify_daf_ind).     *     * @param[in]  dd_handle     Handle to a driver instance.     * @param[in]  conn_handle   The connection handle for the client that is     *                           cancelling the Driver Access Framework     *                           transaction.     */     void (*cancel_daf_trans)(         sns_ddf_handle_t       dd_handle,         void*                  conn_handle);} sns_ddf_driver_if_s;

aDSP初始化流程

aDSP的初始化工作从[Sns_init_dsps.c]文件中的  sns_init()函数开始，其中调用  ->    sns_init_once(); -> SNS_INIT_FUNCTIONS存在一个各个模块的初始化函数指针列表，依次调用各个模块的初始化函数init_ptrs[i]()          -> 其中我们关注传感器相关的[sns_smgr_main_uimg.c]sns_smgr_init() ->        创建了 [sns_smgr_main.c]sns_smgr_task() 进程 ->sns_smgr_hw_init(); ->sns_smgr_process_msg(); ->sns_smgr_process_reg_resp_msg();         ->sns_smgr_process_reg_data() ->sns_smgr_process_reg_devinfo() ->sns_smgr_parse_reg_devinfo_resp() -> 通过drv_fn_ptr->probe()指针，调用相应传感器实现的probe函数。如果某传感器没有实现probe函数，则调用sns_smgr_populate_cfg_from_devinfo()。

 

aDSP上报传感器数据

Sensor上报数据的三种方式：

1，  （Polling）0x00调用一次get_data后启动timer，等到timer到时间后调用sns_ddf_driver_if_s中指定的handle_timer()函数上报一组传感器数据

2，  （DRI）0x80调用enable_sched_data()启用DRI（Data ReadyInterrupt，数据完成中断），按照set_cycle_time指定的ODR（Output Data Rate，数据输出速率）进行数据采集，采集完成后调用sns_ddf_driver_if_s中指定的handle_irq()函数上报传感器数据。

3，  （FIFO）0xD0调用trigger_fifo_data()函数启动FIFO模式，当数据量到达指定的阈值，触发sns_ddf_smgr_data_notify()函数上报一批数据。

关于数据上报流程更详细的见下一篇博客：Linux驱动由浅入深系列：高通sensor架构实例分析之三(adsp上报数据详解)