在学习SLPI侧代码前我们先了解下SEE的registry&config。
registry 放在/persist/sensors/registry/registry中，它是通过config生成的，是给SLPI解析的文件。
config 放在/persist/sensors/registry/config中，它需要RD修改更新，用来生成register以便SLPI使用。每次config update后，即会更新registry。每次reboot后，会重新加载registry。
config都是以.json为后缀的文件，每个物理sensor会有两个json文件，一个是包含所有平台的特殊配置文件，另一个是sensor driver的特殊配置文件。
如果config文件不存在并且sensor driver支持默认参数，则sensor library会将默认参数填充到registry中。
sensor driver可以通过发送request给registry sensor来随时更新registry。
下面来详细介绍下json文件：以高通给的demo文件为例。
/persist/sensors/registry/config/sdm845_lsm6dsm_0.json
{
"config":{
"hw_platform": ["HDK"],
"soc_id": ["341"]
},
"lsm6dso_0_platform":{
"owner": "lsm6dso",
".config":{
"owner": "lsm6dso",
"bus_type":{ "type": "int", "ver": "0",
"data": "1"
},
"bus_instance":{ "type": "int", "ver": "0",
"data": "2"
},
"slave_config":{ "type": "int", "ver": "0",
"data": "0"
},
"min_bus_speed_khz":{ "type": "int", "ver": "0",
"data": "0"
},
"max_bus_speed_khz":{ "type": "int", "ver": "0",
"data": "3300"
},
...
}
上面config为platform-specific configuration， 格式为：target _ sensor_name _ hadware_id
上图说明了platform-specific config中每个元素的含义。
上图为可以用作SPI or I2C的GPIO，这些GPIO是可以复用的，
举个栗子：
bus_type：1，bus_instance：2，slave_config：1
意思为：使用SPI bus，QUP为2，即使用SSC_6、SSC_7、SSC_8、SSC_9、SSC_10、SSC_11这6组GPIO。slave_config为0，即设备连在SSC_6（QUP2 lane4）上。
若bus_type :0 ，其他不变的话。
意思为：使用I2C bus，QUP为2，即使用SSC_2、SSC_3，I2C2这组I2C。slave address为0x01。
上图为sensor中断GPIO。高通强烈建议用户使用中断GPIO时与上图一一对应，所以accel的中断pin为117，mag的中断pin为119。
//sdm845_icm206xx_0.json
"dri_irq_num":{ "type": "int", "ver": "0",
"data": "117"
},
//sdm845_ak0991x_0.json
"dri_irq_num":{ "type": "int", "ver": "0",
"data": "119"
},
下面说下driver-specific configuration
/persist/sensors/registry/config/lsm6dsm_0.json
{
"config":
{
"hw_platform": ["QRD", "MTP", "Dragon", "Surf", "HDK"],
"soc_id": ["336", "341"]
},
"lsm6dso_0":{
"owner": "lsm6dso",
".accel":{
"owner": "lsm6dso",
".config":{
"owner": "lsm6dso",
"is_dri":{ "type": "int", "ver": "0",
"data": "1"
},
"hw_id":{ "type": "int", "ver": "0",
"data": "0"
},
"res_idx":{ "type": "int", "ver": "0",
"data": "2"
},
"sync_stream":{ "type": "int", "ver": "0",
"data": "0"
}
}
},
".gyro":{
"owner": "lsm6dso",
".config":{
"owner": "lsm6dso",
"is_dri":{ "type": "int", "ver": "0",
"data": "1"
},
"hw_id":{ "type": "int", "ver": "0",
"data": "0"
},
"res_idx":{ "type": "int", "ver": "0",
"data": "4"
},
"sync_stream":{ "type": "int", "ver": "0",
"data": "0"
}
}
},
...
}
格式为: sensor_name_hadware_id
上图说明了driver-specific config中每个元素的含义。
了解完registry & config，下面开始学习SLPI层Sensor。
/slpi/ssc/utils/osa/中为整个slpi的入口函数，分析build下osa.scons。可以看到user部分初始化函数为sns_user_pd_init。
env.AddRCInitFunc(
['SSC_SLPI_USER','MODEM_MODEM','SSC_ADSP_USER'],
{
'sequence_group' : 'RCINIT_GROUP_7', # required
'init_name' : 'sns', # required
'init_function' : 'sns_user_pd_init', # required
'dependencies' : ['uTimetick','i2cbsp_init','adsppm_client','pram_mgr_clnt']
})
该init函数为高通开放给custormer的入口函数，可以理解为main函数。
sns_rc sns_user_pd_init()
{
if(false == sns_init_done)
{
/* If enabled, this will delay the framework initialization by 7 seconds.
This is to easily capture init messages when SSC boots up */
#if defined(SNS_DELAY_INIT)
const sns_time one_second_in_ticks = 19200000ULL;
for(int i = 7; i > 0; i--)
{
MSG_1(MSG_SSID_SNS, DBG_MED_PRIO, "init countdown %d ", i);
/* sns_busy_wait is implemented as a sleep() */
sns_busy_wait(one_second_in_ticks);
}
#endif
...
sns_fw_init();
...
}
这里我们不关心其他init，只研究sns_fw_init。我们开始进入SEE的framework层。
1.framework层
code放在/slpi/ssc/framework/中。
另外还要注意一下，SNS_DELAY_INIT这个宏，当定义后，会delay 7s后再进行framework 初始化。一般在debug时会加上该宏，用来抓取SSC boots up时的log。
//sns_fw_init.c
int sns_fw_init(void)
{
...
rc = sns_sensor_init_fw(); //No.1
...
rc = sns_sensor_instance_init_fw(); //No.2
...
rc = register_static_sensors(); //No.3
...
return 0;
}
//sns_sensor.c
sns_rc
sns_sensor_init_fw(void)
{
...
sensor_cb = (sns_sensor_cb)
{
.struct_len = sizeof(sensor_cb),
.get_service_manager = &get_service_manager,
.get_sensor_instance = &get_sensor_instance,
.create_instance = &sns_sensor_instance_init,
.remove_instance = &sns_sensor_instance_deinit,
.get_library_sensor = &get_library_sensor,
.get_registration_index = &get_registration_index,
};
return SNS_RC_SUCCESS;
}
//sns_sensor_instance.c
sns_rc
sns_sensor_instance_init_fw(void)
{
instance_cb = (sns_sensor_instance_cb)
{
.struct_len = sizeof(instance_cb),
.get_service_manager = &get_service_manager,
.get_client_request = &get_client_request,
.remove_client_request = &remove_client_request,
.add_client_request = &add_client_request
};
return SNS_RC_SUCCESS;
}
在sns_fw_init函数中我们着重分析上面三个函数，
No.1中是sns_sensor_cb的回调函数，这里需要注意下，后面分析sensor driver时会非常频繁的用到这些回调函数。
No.2中是sns_sensor_instance_cb的回到函数，同样需要注意下，后面使用也很频繁。
No.3中是所有sensor的静态注册函数。需要说明下，这个静态注册非常有意思。为了方便添加和移除sensor，高通SDM845中将注册函数写到build文件中，每次build image时，会动态的将build中注册函数写到特定的sensor注册文件中，以便register_static_sensors()使用。
举个例子，以accel的driver icm206xx为例，进入/slpi/ssc/sensors/icm206xx/中，看下build脚本sns_icm206xx.scons。
if 'USES_SSC_STATIC_LIB_BUILDER' in env:
if 'SSC_TARGET_HEXAGON' in env['CPPDEFINES']:
env.AddSSCSU(inspect.getfile(inspect.currentframe()),
flavor = ["hexagon"],
register_func_name = "sns_register_icm206xx",
binary_lib = False,
add_island_files = icm206xx_island_enable)
上面的含义是，若USES_SSC_STATIC_LIB_BUILDER在环境中，则往环境中添加如下数据。。。。可以看到register_func_name = “sns_register_icm206xx”，后面解析可以知道sns_register_icm206xx为accel sensor的入口函数，这里仅说明一下。
那么build环境中是否有USES_SSC_STATIC_LIB_BUILDER呢？
在SLPI build脚本ssc_static_lib_builder.py中中可以看到有加入该flag。
env.AddUsesFlags('USES_SSC_STATIC_LIB_BUILDER')
env.AddMethod(add_ssc_su, 'AddSSCSU')
那如何使用sensor入口函数sns_register_icm206xx呢？
还是在ssc_static_lib_builder.py中，有个函数generate_static_sensor_list()
if "sns_register_suid_sensor" == register_func_name:
static_sensors.insert(0, (register_func_name, registration_cnt))
else:
static_sensors.append((register_func_name, registration_cnt))
#==============================================================================
# Generates sns_static_sensors.c
#==============================================================================
def generate_static_sensor_list(env, tags):
global static_sensors
if env.IsKeyEnable(tags) is True:
logger.info("generate_static_sensor_list() called with %d sensors" % len(static_sensors))
#dest = os.path.join(env.subst('${SSC_ROOT}'), 'framework', 'src')
#if not os.path.isdir(dest) or not os.listdir(dest):
# return None
if len(static_sensors) == 0:
logger.error("There are no static sensors?!!!")
return None
static_sensors_file = os.path.join(env.subst('${SSC_ROOT}'),
'framework', 'src', 'sns_static_sensors.c')
fo = open(static_sensors_file, "w")
fo.write("/* Autogenerated file. Manual modification is pointless. */\n\n")
fo.write("#include \"sns_rc.h\"\n")
fo.write("#include \"sns_register.h\"\n")
fo.write("#include \"sns_types.h\"\n")
fo.write("\n")
for reg_func,reg_cnt in static_sensors:
fo.write("sns_rc %s(sns_register_cb const *register_api);\n" % reg_func)
fo.write("\nconst sns_register_entry sns_register_sensor_list[] =\n{\n")
for reg_func,reg_cnt in static_sensors:
fo.write(" { %s, %i},\n" % (reg_func, reg_cnt))
fo.write("};\n\n")
fo.write("const uint32_t sns_register_sensor_list_len = ARR_SIZE(sns_register_sensor_list);\n\n")
fo.close()
这个函数的作用是根据所有sensor的build脚本xxx.scons中入口函数，生成一个新的文件sns_static_sensors.c。
ok，编译完后git diff下，看到了生成的sns_static_sensors.c中新加了sns_register_icm206xx。
sns_rc sns_gyro_cal_register(sns_register_cb const *register_api);
sns_rc sns_gyro_rot_matrix_register(sns_register_cb const *register_api);
+sns_rc sns_register_icm206xx(sns_register_cb const *register_api);
sns_rc sns_register_interrupt(sns_register_cb const *register_api);
const sns_register_entry sns_register_sensor_list[] =
{
{ sns_gyro_rot_matrix_register, 1},
+ { sns_register_icm206xx, 1},
{ sns_register_interrupt, 1},
}
我想大家应该都了解了吧，这样做的目的就是很快捷的添加或删除driver。
回到No.3，register_static_sensors函数中，
static sns_rc register_static_sensors(void)
{
sns_register_cb reg_cb = (sns_register_cb) //No.1
{
.struct_len = sizeof(reg_cb),
.init_sensor = &sns_sensor_init
};
for(int i = 0; i < sns_register_sensor_list_len; i++)
{
for(int j = 0; j < sns_register_sensor_list[i].cnt; j++) //No.2
{
...
sns_register_sensor_list[i].func(®_cb);
sns_sensor_library_start(library); //No.3
...
}
}
return SNS_RC_SUCCESS;
}
No.1中，sns_register_cb的回调函数，每个sensor driver入口函数都会调用该数据结构中.init_sensor函数。该函数的主要作用是，（1）判断是否是island mode，后面会将什么是island mode。（2）将相关数据结构加入到链表。比如library、sensors等等。
No.2中，上面生成sns_static_sensors.c文件中的sns_register_sensor_list.func，即sensor注册的入口函数；然后执行。执行后就进入的sensor driver的世界。
No.3中，sns_sensor_library_start，主要调用sensor_api->init函数和sensor_api->get_sensor_uid函数，至于sensor_api是什么，后面会讲，这里不懂先略过。
Ok，framework层初始化流程部分讲了一部分，下面开始讲sensor driver层，在sensor driver层讲解中顺带会说下相关的framework层，这样可以更深入的了解SEE框架。
2.sensor driver层
code放在/slpi/ssc/sensors/中
我们研究高通提供的demo sensor driver code：lsm6dso。
进入qcom_firware->slpi_proc->ssc->sensors->lsm6dso目录后，首先下看下build脚本。
####lsm6dso.scons######
Import('env')
import os,inspect
if ('SSC_TARGET_HEXAGON_MDSP' in env['CPPDEFINES']):
Return()
lsm6dso_island_enable = False
if 'SNS_ISLAND_INCLUDE_LSM6DSO' in env: #No.1
lsm6dso_island_enable = True
if ('SSC_TARGET_HEXAGON' in env['CPPDEFINES']) and ('SENSORS_DD_DEV_FLAG' not in env):
env.AddSSCSU(inspect.getfile(inspect.currentframe()), #No.2
register_func_name = "sns_register_lsm6dso",
binary_lib = False,
add_island_files = lsm6dso_island_enable)
if 'SENSORS_DD_DEV_FLAG' in env: #No.3
ME = inspect.getfile(inspect.currentframe())
MY_ROOT = os.path.dirname(os.path.dirname(ME))
REMOVE_FILES = env.FindFiles(['*.*'], MY_ROOT)
env.CleanPack(env['SSC_BUILD_TAGS'], REMOVE_FILES)
No.1中若存在flag=SNS_ISLAND_INCLUDE_LSM6DSO，则lsm6dso_island_enable=true，即lsm6dso被设置成island mode。何为Island mode，高通解释island有着很低的功耗。
如何设置成为island mode呢？
在build脚本上，我们需要设置flag，在build/ssc.scons中加入。
env.AddUsesFlags(['SNS_ISLAND_INCLUDE_LSM6DSO'])
在sensor driver code上，我们我要
(1) 把sensor中这些API放到sns_< drv_name >_sensor_island.c中实现
//本例为sns_lsm6dso_sensor_island.c
sns_sensor_api 内容
get_sensor_uid()
set_client_request() only for accel driver libraries
(2)把sensor instance中这些API放到sns_< drv_name >_sensor_instance_island.c中实现
//本例为sns_lsm6dso_sensor_instance_island.c
sns_sensor_instance_api内容
notify_event()
set_client_config() only for accel driver libraries
(3)把所有sensor & sensor instance island中调用的函数放到sns_< drv_name >_hal_island.c中实现：
//本例为sns_lsm6dso_hal_island.c
lsm6dso_com_write_wrapper()
lsm6dso_start_fifo_streaming()
and so on...
Normal情况哪些API放在哪些文件中呢？
(1) 把sensor中这些API放到sns_< drv_name >_sensor.c中实现
init()
deinit()
set_client_request() for non-accel driver libraries
notify_event()
(2) 把sensor instance中这些API放到sns_< drv_name >_sensor_instance.c中实现
init()
deinit()
set_client_config() only for non-accel driver libraries
(3)所有sensor & sensor instance 非island中调用的函数放到sns_< drv_name >_hal.c中实现。
No.2中设置flag=SSC_TARGET_HEXAGON是动态注册，registry_func_name=”sns_register_lsm6dso”为sensor driver的入口函数。binary_lib为是否是二进制lib，高通的一些虚拟sensor比如计步器、amd、smd等等都是以lib形式提供给customer的。customer只要调用API使用即可，不需要知道如何实现。
No.3中设置flag=SENSORS_DD_DEV_FLAG是静态注册，在SDM845上使用的均为动态注册。
接着来到入口函数中：
//sns_lsm6dso.c
sns_rc sns_register_lsm6dso(sns_register_cb const *register_api)
{
int i = 0;
/** Register Sensors */
for(i = 0; i< ARR_SIZE(lsm6dso_supported_sensors) ; i++) {
register_api->init_sensor(sizeof(lsm6dso_state), lsm6dso_supported_sensors[i].sensor_api,
lsm6dso_supported_sensors[i].instance_api);
}
return SNS_RC_SUCCESS;
}
//sns_lsm6dso_sensor_island.c
const lsm6dso_sensors lsm6dso_supported_sensors[ MAX_SUPPORTED_SENSORS ] = {
{LSM6DSO_ACCEL, &lsm6dso_accel_sensor_api, &lsm6dso_sensor_instance_api},
{LSM6DSO_GYRO, &lsm6dso_gyro_sensor_api, &lsm6dso_sensor_instance_api},
{LSM6DSO_MOTION_DETECT , &lsm6dso_motion_detect_sensor_api, &lsm6dso_sensor_instance_api},
{LSM6DSO_SENSOR_TEMP, &lsm6dso_sensor_temp_sensor_api, &lsm6dso_sensor_instance_api}
};
上面入口函数中注册四组api，每组api包含sns_sensor_api 和 sns_sensor_instance_api。
sns_sensor_api数据结构放在sns_lsm6dso_sensor_island.c中；该部分主要是为了sensor的初始化。
sns_sensor_instance_api数据结构放在sns_lsm6dso_sensor_instance_island.c中；该部分主要是为了sensor对应的操作。
以LSM6DSO_ACCEL为例：
1： sns_sensor_api定义在sns_sensor.h中，结构如下：
typedef struct sns_sensor_api
{
uint32_t struct_len;
/**
* Initialize a Sensor to its hard-coded/default state. Generate
* requests for any other necessary data (e.g. Registry data). A call to
* sns_sensor_api::deinit will precede any subsequent calls to this function.
*
* @param[i] this Sensor reference
*
* @return
* SNS_RC_INVALID_STATE - Requisite hardware not available
* SNS_RC_POLICY - Required services not available
* SNS_RC_SUCCESS
*/
sns_rc (*init)(
sns_sensor *const this);
/**
* Release all hardware and software resources associated with this Sensor
*
* @param[i] this Sensor reference
*
* @return
* SNS_RC_INVALID_STATE - Error occurred: some resource could not be released
* SNS_RC_SUCCESS
*/
sns_rc (*deinit)(
sns_sensor *const this);
/**
* Each Sensor must have a globally unique identifier; each algorithm
* and driver will define their own. If a Sensor may be loaded twice on the
* system, it is responsible for returning two unique values. These must
* not change across device reboots.
*
* @param[i] this Sensor reference
*
* @return The unique identifier for this Sensor
*/
sns_sensor_uid const* (*get_sensor_uid)(
sns_sensor const *const this);
/**
* Notification to the client that some data has been received.
*
* The client must use the sns_event_service to obtain this data
* for processing.
*
* @return
* SNS_RC_INVALID_STATE - A client error occurred; Framework shall destroy
* client
* SNS_RC_NOT_AVAILABLE - A transitory error occurred; Framework shall
* remove all outstanding input
* SNS_RC_INVALID_LIBRARY_STATE - A permanent error occurred; Framework shall
* destroy all sensors present in the client library
* SNS_RC_SUCCESS
*/
sns_rc (*notify_event)(
sns_sensor *const this);
/**
* Add, remove, or update a client's request to this Sensor.
*
* For each new request sent by a client, the Sensor (via this function)
* will receive the new_request. If the client has an active request
* (which is to be replaced), it will be specified in exist_request.
*
* If 'remove' is false:
* A client has sent a new request to this Sensor. Determine if any
* active Sensor Instance in sns_sensor_cb::get_sensor_instance()
* will handle this request. If yes, use add_client_request to associate
* this new request with that existing Instance.
*
* If not, instantiate and initialize a new Sensor Instance with the
* appropriate configuration, and similarly use add_client_request.
*
* In either case, if exist_request is provided and new_request provides
* a superceding configuration, exist_request must be removed via
* remove_client_request.
*
* If 'remove' is true:
* Remove this client request by sns_sensor_instance_cb::remove_client_request;
* re-arrange any remaining client requests/sensor instances.
*
* In all cases, if the result of the operation is a Sensor Instance with
* zero clients, sns_sensor_cb::remove_instance must be called.
*
* @param[i] this Sensor reference
* @param[i] exist_request If this request comes-in over an existing stream,
* this is the existing request.
* @param[i] new_request New request just received
* @param[i] remove If the client no longer requires this data
*
* @return
* The Sensor Instance chosen to handle this new client. NULL if an error
* occurred during processing; or if "remove" was true.
* Or sns_instance_no_error (see above).
*/
struct sns_sensor_instance* (*set_client_request)(
sns_sensor *const this,
struct sns_request const *exist_request,
struct sns_request const *new_request,
bool remove);
} sns_sensor_api;
上面每个函数都有注释，这里不再解释。
//sns_lsm6dso_sensor_island.c , sns_sensor_api放在island文件中，上面island介绍中有解释。
sns_sensor_api lsm6dso_accel_sensor_api =
{
.struct_len = sizeof(sns_sensor_api),
.init = &lsm6dso_accel_init,
.deinit = &lsm6dso_accel_deinit,
.get_sensor_uid = &lsm6dso_get_sensor_uid,
.set_client_request = &lsm6dso_set_client_request,
.notify_event = &lsm6dso_sensor_notify_event,
};
Initialization
上面说到sns_sensor_library_start，主要调用sensor_api->init函数和sensor_api->get_sensor_uid函数，下面分别介绍.init和.get_sensor_uid函数。
（1）lsm6dso_accel_init
//sns_lsm6dso_accel_sensor.c
sns_rc lsm6dso_accel_init(sns_sensor *const this)
{
lsm6dso_state *state = (lsm6dso_state*)this->state->state; //No.1
lsm6dso_acc_publish_attributes(this); //No.2
lsm6dso_init_sensor_info(this, &((sns_sensor_uid)ACCEL_SUID), LSM6DSO_ACCEL); //No.3
DBG_PRINT(state->diag_service, this, LOW, __FILENAME__, __LINE__, "accel init");
return SNS_RC_SUCCESS;
}
No.1中：此形式应用非常广泛，同this指针中获取lsm6dso_state。
lsm6dso_state定义在sns_lsm6dso_sensor.h中，是sensor driver两个非常重要的数据结构之一，当然，另外一个是lsm6dso_instance_state。
（注：这里写成this，大家都明白什么意思了吧，虽然c语言不是面向对象语言，但底层开发处处用到面向对象的思想，this这很明显的说明sns_sensor类似于基类，不同的sensor都继承该基类，该基类数据形式都是common的，强制类型转换成每个sensor独有的数据；在C语言中只不过不叫基类而已，在这里叫做framework，在kernel中叫做core。）
No.2中：比较重要，将accel的atrributes publish到attribute service中并保存起来。
void lsm6dso_acc_publish_attributes(sns_sensor *const this)
{
const char type[] = "accel";
const uint32_t active_current[3] = {25, 85, 150}; //uA
const uint32_t sleep_current = 3; //uA
lsm6dso_publish_def_attributes(this);
{
sns_std_attr_value_data values[] = {SNS_ATTR, SNS_ATTR, SNS_ATTR, SNS_ATTR, //No.a
SNS_ATTR, SNS_ATTR/*, SNS_ATTR, SNS_ATTR,SNS_ATTR*/};
values[0].has_flt = true;
values[0].flt = LSM6DSO_ODR_13;
values[1].has_flt = true;
values[1].flt = LSM6DSO_ODR_26;
values[2].has_flt = true;
values[2].flt = LSM6DSO_ODR_52;
values[3].has_flt = true;
values[3].flt = LSM6DSO_ODR_104;
values[4].has_flt = true;
values[4].flt = LSM6DSO_ODR_208;
values[5].has_flt = true;
values[5].flt = LSM6DSO_ODR_416;
//QC currently we are limiting to 416
/*
values[6].has_flt = true;
values[6].flt = LSM6DSO_ODR_833;
values[7].has_flt = true;
values[7].flt = LSM6DSO_ODR_1660;
values[8].has_flt = true;
values[8].flt = LSM6DSO_ODR_3330;
values[9].has_flt = true;
values[9].flt = LSM6DSO_ODR_6660;
*/
sns_publish_attribute(this, SNS_STD_SENSOR_ATTRID_RATES,
values, ARR_SIZE(values), false);
}
{ //No.b
sns_std_attr_value_data value = sns_std_attr_value_data_init_default;
value.str.funcs.encode = pb_encode_string_cb;
value.str.arg = &((pb_buffer_arg)
{ .buf = type, .buf_len = sizeof(type) });
sns_publish_attribute(
this, SNS_STD_SENSOR_ATTRID_TYPE, &value, 1, false);
}
{ //No.c
sns_std_attr_value_data values[] = {SNS_ATTR, SNS_ATTR, SNS_ATTR, SNS_ATTR};
int i;
for(i = 0; i < ARR_SIZE(values); i++)
{
values[i].has_flt = true;
values[i].flt = lsm6dso_accel_resolutions[i];
}
sns_publish_attribute(this, SNS_STD_SENSOR_ATTRID_RESOLUTIONS,
values, i, false);
}
{ //No.d
sns_std_attr_value_data values[] = {SNS_ATTR, SNS_ATTR, SNS_ATTR};
int i;
for(i = 0; i < ARR_SIZE(active_current); i++)
{
values[i].has_sint = true;
values[i].sint = active_current[i];
}
sns_publish_attribute(this, SNS_STD_SENSOR_ATTRID_ACTIVE_CURRENT,
values, i, false);
}
{ //No.e
sns_std_attr_value_data value = sns_std_attr_value_data_init_default;
value.has_sint = true;
value.sint = sleep_current; //uA
sns_publish_attribute(
this, SNS_STD_SENSOR_ATTRID_SLEEP_CURRENT, &value, 1, false);
}
{ //No.f
sns_std_attr_value_data values[] = {SNS_ATTR, SNS_ATTR, SNS_ATTR, SNS_ATTR};
sns_std_attr_value_data range1[] = {SNS_ATTR, SNS_ATTR};
range1[0].has_flt = true;
range1[0].flt = LSM6DSO_ACCEL_RANGE_2G_MIN;
range1[1].has_flt = true;
range1[1].flt = LSM6DSO_ACCEL_RANGE_2G_MAX;
values[0].has_subtype = true;
values[0].subtype.values.funcs.encode = sns_pb_encode_attr_cb;
values[0].subtype.values.arg =
&((pb_buffer_arg){ .buf = range1, .buf_len = ARR_SIZE(range1) });
sns_std_attr_value_data range2[] = {SNS_ATTR, SNS_ATTR};
range2[0].has_flt = true;
range2[0].flt = LSM6DSO_ACCEL_RANGE_4G_MIN;
range2[1].has_flt = true;
range2[1].flt = LSM6DSO_ACCEL_RANGE_4G_MAX;
values[1].has_subtype = true;
values[1].subtype.values.funcs.encode = sns_pb_encode_attr_cb;
values[1].subtype.values.arg =
&((pb_buffer_arg){ .buf = range2, .buf_len = ARR_SIZE(range2) });
sns_std_attr_value_data range3[] = {SNS_ATTR, SNS_ATTR};
range3[0].has_flt = true;
range3[0].flt = LSM6DSO_ACCEL_RANGE_8G_MIN;
range3[1].has_flt = true;
range3[1].flt = LSM6DSO_ACCEL_RANGE_8G_MIN;
values[2].has_subtype = true;
values[2].subtype.values.funcs.encode = sns_pb_encode_attr_cb;
values[2].subtype.values.arg =
&((pb_buffer_arg){ .buf = range3, .buf_len = ARR_SIZE(range3) });
sns_std_attr_value_data range4[] = {SNS_ATTR, SNS_ATTR};
range4[0].has_flt = true;
range4[0].flt = LSM6DSO_ACCEL_RANGE_16G_MIN;
range4[1].has_flt = true;
range4[1].flt = LSM6DSO_ACCEL_RANGE_16G_MAX;
values[3].has_subtype = true;
values[3].subtype.values.funcs.encode = sns_pb_encode_attr_cb;
values[3].subtype.values.arg =
&((pb_buffer_arg){ .buf = range4, .buf_len = ARR_SIZE(range4) });
sns_publish_attribute(this, SNS_STD_SENSOR_ATTRID_RANGES,
values, ARR_SIZE(values), true);
}
{ //No.g
sns_std_attr_value_data values[] = {SNS_ATTR};
char const proto1[] = "sns_accel.proto";
values[0].str.funcs.encode = pb_encode_string_cb;
values[0].str.arg = &((pb_buffer_arg)
{ .buf = proto1, .buf_len = sizeof(proto1) });
sns_publish_attribute(this, SNS_STD_SENSOR_ATTRID_API,
values, ARR_SIZE(values), false);
}
}
看似好多东西啊，其实这些东西都是简单的参数。就是lsm6dso driver中accel的一些属性。
sns_publish_attribute参数分别代表：1，sns_sensor；2，attribute_id；3，value；4，value length；5，completed代表是否是最后一被设置的属性，若为true，后续不能修改该属性；若为false，后续可以修改该属性。
No.a中，sns_std_attr_value_data是一个保存attr value的data，初始化元素为SNS_ATTR
#define SNS_ATTR sns_std_attr_value_data_init_default
#define sns_std_attr_value_data_init_default {false, sns_std_attr_value_init_default, {{NULL}, NULL}, false, 0, false, 0, false, 0}
typedef struct _sns_std_attr_value_data {
bool has_subtype;
sns_std_attr_value subtype;
pb_callback_t str;
bool has_flt;
float flt;
bool has_sint;
int64_t sint;
bool has_boolean;
bool boolean;
/* @@protoc_insertion_point(struct:sns_std_attr_value_data) */
} sns_std_attr_value_data;
可以看到有6个SNS_ATTR，即后面有6个value[ 0 ~ 5 ]，value的has_flt位均设为true，value的flt为LSM6DSO_ODR_13、LSM6DSO_ODR_26、LSM6DSO_ODR_52等等，
设置完后，通过sns_publish_attribute将attribute_id为SNS_STD_SENSOR_ATTRID_RATES publish到attribute service中。
后面简略的介绍下sns_publish_attribute函数后续流程。
//sns_attribute_util.c
SNS_SECTION(".text.sns") void //No.a
sns_publish_attribute(sns_sensor *const sensor,
uint32_t attribute_id, sns_std_attr_value_data const *values,
uint32_t values_len, bool completed)
{
size_t attribute_len = 0;
sns_std_attr std_attr = (sns_std_attr) //No.b
{ .attr_id = attribute_id, .value.values.funcs.encode = &sns_pb_encode_attr_cb,
.value.values.arg = &((pb_buffer_arg){ .buf = values, .buf_len = values_len }) };
if(pb_get_encoded_size(&attribute_len, sns_std_attr_fields, &std_attr)) //No.c
{
sns_service_manager *manager = sensor->cb->get_service_manager(sensor);
sns_attribute_service *attribute_service =
(sns_attribute_service*)manager->get_service(manager, SNS_ATTRIBUTE_SERVICE);
uint8_t attribute[attribute_len];
pb_ostream_t stream = pb_ostream_from_buffer(attribute, attribute_len);
if(pb_encode(&stream, sns_std_attr_fields, &std_attr)) //No.d
attribute_service->api->publish_attribute(attribute_service, sensor,
attribute, attribute_len, attribute_id, completed);
// PEND: Print a message upon errors
}
}
No.a 中 SNS_SECTION(“.text.sns”)，将函数放到.text.sns段。
No.b 中根据前面的values填充pb_buffer_arg、填充sns_std_attr数据结构。
typedef struct _sns_std_attr {
int32_t attr_id;
sns_std_attr_value value;
/* @@protoc_insertion_point(struct:sns_std_attr) */
} sns_std_attr;
No.c 中获取sns_service_manager，然后通过get_service来获取attribute service。
No.d 中通过attribute service中api进行push_attribute。
SNS_SECTION(".text.sns") static sns_rc
publish_attribute(sns_attribute_service *this, struct sns_sensor *sensor,
void const *attribute, uint32_t attribute_len, sns_attribute_id attribute_id,
bool completed)
{
UNUSED_VAR(this);
UNUSED_VAR(completed);
sns_list_iter iter;
sns_fw_sensor *fw_sensor = (sns_fw_sensor*)sensor; //No.a
sns_attribute *new_attr;
sns_mem_heap_id heap =
(SNS_STD_SENSOR_ATTRID_TYPE == attribute_id ||
SNS_STD_SENSOR_ATTRID_VENDOR == attribute_id)
? SNS_HEAP_ISLAND : SNS_HEAP_MAIN;
SNS_ISLAND_EXIT();
new_attr = sns_malloc(heap, sizeof(*new_attr) + attribute_len);
if(SNS_HEAP_ISLAND == heap && NULL == new_attr)
{
new_attr = sns_malloc(SNS_HEAP_MAIN, sizeof(*new_attr) + attribute_len);
fw_sensor->island_operation = SNS_ISLAND_STATE_ISLAND_DISABLED;
}
SNS_ASSERT(NULL != new_attr);
sns_list_item_init(&new_attr->list_entry, new_attr);
new_attr->id = attribute_id;
new_attr->value_len = attribute_len;
sns_memscpy(&new_attr->value, attribute_len, attribute, attribute_len);
for(sns_list_iter_init(&iter, &fw_sensor->attr_info->attributes, true);
NULL != sns_list_iter_curr(&iter);
sns_list_iter_advance(&iter))
{
sns_attribute *attr =
(sns_attribute*)sns_list_item_get_data(sns_list_iter_curr(&iter));
if(attr->id == attribute_id)
{
sns_list_iter_remove(&iter);
sns_free(attr);
break;
}
}
sns_list_iter_insert(&iter, &new_attr->list_entry, false);
process_special_attributes(new_attr, fw_sensor); //No.b
return SNS_RC_SUCCESS;
}
No.a中有个重要的数据结构sns_fw_sensor，该数据结构定义在sns_fw_sensor.h，每个sensor都有自己的sns_fw_sensor。将sns_sensor地址赋给sns_fw_sensor，所以sns_fw_sensor第一个成员为sns_sensor，而且sns_fw_sensor只用在framework层，不开放给sensor开发者使用。
No.b中process_special_attributes继续：
SNS_SECTION(".text.sns") static void
process_special_attributes(sns_attribute *new_attr, sns_fw_sensor *fw_sensor)
{
if(SNS_STD_SENSOR_ATTRID_AVAILABLE == new_attr->id)
{
bool available = (bool)decode_attribute(new_attr, &pb_decode_attr_value_cb);
if(available != sns_attr_info_get_available(fw_sensor->attr_info))
{
char data_type[32];
sns_attr_info_get_data_type(fw_sensor->attr_info, data_type, sizeof(data_type));
sns_attr_info_set_available(fw_sensor->attr_info, available);
sns_suid_sensor_apprise(data_type);
}
sns_diag_register_sensor(fw_sensor);
}
else if(SNS_STD_SENSOR_ATTRID_TYPE == new_attr->id)
{
sns_attr_priority priority = { false, false };
char const *data_type =
(char*)decode_attribute(new_attr, &pb_decode_attr_value_cb);
SNS_ASSERT(NULL != data_type);
sns_attr_info_set_data_type(fw_sensor->attr_info, data_type);
for(uint8_t i = 0; i < ARR_SIZE(event_priority_datatypes); i++)
{
if(0 == strcmp(data_type, event_priority_datatypes[i]))
{
priority.event_priority = true;
break;
}
}
for(uint8_t i = 0; i < ARR_SIZE(req_priority_datatypes); i++)
{
if(0 == strcmp(data_type, req_priority_datatypes[i]))
{
priority.req_priority = true;
break;
}
}
sns_attr_info_set_priority(fw_sensor->attr_info, priority);
}
else if(SNS_STD_SENSOR_ATTRID_VENDOR == new_attr->id)
{
char const *vendor = (char*)decode_attribute(new_attr, &pb_decode_attr_value_cb);
sns_attr_info_set_vendor(fw_sensor->attr_info, vendor);
}
else if(SNS_STD_SENSOR_ATTRID_PHYSICAL_SENSOR == new_attr->id &&
!sns_attr_info_get_is_physical_sensor(fw_sensor->attr_info))
{
bool physical_sensor = (bool)decode_attribute(new_attr, &pb_decode_attr_value_cb);
sns_attr_info_set_is_physical_sensor(fw_sensor->attr_info, physical_sensor);
}
}
上面函数主要根据attribute_id进行不同的处理，并将数据保存在fw_sensor->attr_info中。
Ok，上面关于sns_publish_attribute大概介绍完毕，有兴趣的童鞋可以仔细研究，没有兴趣的话不影响大局，可以略过不看，只需记得attribte参数放进sns_fw_sensor->attr_info中，以便后续使用！
回到lsm6dso_acc_publish_attributes中。
No.b中：同样publish attribute_id为SNS_STD_SENSOR_ATTRID_TYPE的value。
No.c中：同样publish attribute_id为SNS_STD_SENSOR_ATTRID_RESOLUTIONS的value。
No.d中：同样publish attribute_id为SNS_STD_SENSOR_ATTRID_ACTIVE_CURRENT的value。
No.e中：同样publish attribute_id为SNS_STD_SENSOR_ATTRID_SLEEP_CURRENT的value。
No.f中：同样publish attribute_id为SNS_STD_SENSOR_ATTRID_RANGES的value。
No.g中：同样publish attribute_id为SNS_STD_SENSOR_ATTRID_API的value。API使用的是sns_accel.proto。
回到lsm6dso_accel_init的函数lsm6dso_init_sensor_info中，
首先介绍几个数据结构。之前我们知道有个struct sns_sensor，sns_sensor有个成员为struct sns_sensor_cb const*cb我们没有介绍过。
//sns_sensor.h
typedef struct sns_sensor
{
/* Functions which call back into the framework; provided by the Framework */
struct sns_sensor_cb const *cb;
/* API implementation provided for and by this Sensor */
struct sns_sensor_api const *sensor_api;
/* The associated API for an Sensor Instances created for and by this
* Sensor. */
struct sns_sensor_instance_api const *instance_api;
/* State space allocated by the Framework for the sole use of the Sensor
* developer. */
struct sns_sensor_state *state;
} sns_sensor;
//sns_sensor.h
typedef struct sns_sensor_cb
{
uint32_t struct_len;
/**
* Get a reference to the Service Manager. With this object, a reference
* to any other utility service can be obtained.
* * @param[i] this Sensor reference
* * @return Service Manager reference
*/
struct sns_service_manager* (*get_service_manager)(
sns_sensor const *this);
/**
* Return the next Sensor Instance associated with this Sensor.
* * Each Sensor has a list of associated Sensor Instances; entries are added
* to that list within calls to 'create_instance', and removed from the
* list when it services no client requests.
* * Each call to this function iterates over the list, and returns the next
* entry. NULL is returned at the end of the list, or if the list is empty.
* * @param[i] this Sensor reference
* @param[i] first Return the first instance; reset the internal iterator
* Must be called first to initialize iteration
* * @return Next Sensor Instance associated with this Sensor
*/
struct sns_sensor_instance* (*get_sensor_instance)(
sns_sensor const *this,
bool first);
/**
* Allocate and initialize a new Sensor Instance to be associated with this
* Sensor. Will call sns_sensor_instance::init.
* * @note Direct pointers to the returned value should not be saved.
* * @param[i] this Sensor reference
* @param[i] stateLen Allocation size for sns_sensor_instance::state
* * @return Newly created Sensor Instance
*/
struct sns_sensor_instance* (*create_instance)(
sns_sensor *this,
uint32_t state_len);
/**
* Remove and deallocate a Sensor Instance. Will call
* sns_sensor_instance::deinit.
* * @param[i] instance Instance received within set_client_request
*/
void (*remove_instance)(
struct sns_sensor_instance *instance);
/**
* Return the next Sensor associated with this library.
* * Each Sensor is a member of a library; each library may contain several
* Sensors. Sensors may be removed from a library upon errors, but no
* entries are added after Framework initialization has completed.
* * Each call to this function iterates over the list, and returns the next
* entry. NULL is returned at the end of the list, or if the list is empty.
* * This function is intended to be used by Sensors which share physical
* hardware with another sensor, and hence must share state/instances.
* * @param[i] this Sensor reference
* @param[i] first Return the first sensor; reset the internal iterator;
* Must be called first to initialize iteration
* * @return Next Sensor associated with this library.
*/
struct sns_sensor* (*get_library_sensor)(
sns_sensor const *this,
bool first);
/**
* If multiple copies of this Sensor Library have been registered with SEE,
* this returns the index (starting at '0') of this particular copy. See
* parameter registration_cnt of env.AddSSCSU.
* * @param[i] this Sensor reference
* * @return Library registration index
*/
uint32_t (*get_registration_index)(
sns_sensor const *this);
} sns_sensor_cb;
sns_sensor_cb是通过SEE framework 提供来给sensor使用的callback。其中包含5个函数，分别是
No.3中：填充lsm6dso_state，
通过sns_sensor ->cb->get_service_manager来获取一个sns_service_manager的handle。sns_service_manager是可以管理所有service的数据结构。
然后在介绍下init_dependencies比较重要：
//sns_lsm6dso_sensor.c
static char def_dependency[][MAX_DEP_LENGTH] = {
"interrupt", "async_com_port", "timer", "data_acquisition_engine", "registry"
};
static void init_dependencies(sns_sensor *const this)
{
int i = 0;
lsm6dso_state *state = (lsm6dso_state*)this->state->state;
DBG_PRINT(state->diag_service, this, LOW, __FILENAME__, __LINE__, "init_dependencies sensor");
for(i=0;i<ARR_SIZE(def_dependency);i++)
{
send_suid_req(this, def_dependency[i], strlen(def_dependency[i]));
}
}
accel 所依赖的platform sensor。有interrupt、async_com_port、timer、registry等等。
send_suid_req函数内容比较中要！因为后面很多地方会用到，这里我们重点介绍下：
static void send_suid_req(sns_sensor *this, char *const data_type, uint32_t data_type_len)
{
lsm6dso_state *state = (lsm6dso_state*)this->state->state;
if(state->fw_stream == NULL) //No.a
{
sns_service_manager *manager = this->cb->get_service_manager(this);
sns_stream_service *stream_service =
(sns_stream_service*)manager->get_service(manager, SNS_STREAM_SERVICE);
stream_service->api->create_sensor_stream(stream_service, this, sns_get_suid_lookup(),
&state->fw_stream);
}
if(state->fw_stream != NULL) //No.b
{
size_t encoded_len;
pb_buffer_arg data = (pb_buffer_arg){ .buf = data_type, .buf_len = data_type_len };
uint8_t buffer[50];
sns_suid_req suid_req = sns_suid_req_init_default;
suid_req.has_register_updates = true;
suid_req.register_updates = true;
suid_req.data_type.funcs.encode = &pb_encode_string_cb;
suid_req.data_type.arg = &data;
sns_rc rc = SNS_RC_SUCCESS;
encoded_len = pb_encode_request(buffer, sizeof(buffer), &suid_req, sns_suid_req_fields, NULL);
if(0 < encoded_len)
{
sns_request request = (sns_request){
.request_len = encoded_len, .request = buffer, .message_id = SNS_SUID_MSGID_SNS_SUID_REQ };
rc = state->fw_stream->api->send_request(state->fw_stream, &request);
}
if(0 >= encoded_len || SNS_RC_SUCCESS != rc)
{
DBG_PRINT(state->diag_service, this, ERROR, __FILENAME__, __LINE__,
"encoded_len=%d rc=%u", encoded_len, rc);
}
}
}
No.a中：首先介绍个数据结构sns_data_stream
//sns_data_stream.h
typedef struct sns_data_stream
{
struct sns_data_stream_api *api;
} sns_data_stream;
typedef struct sns_data_stream_api
{
uint32_t struct_len;
/**
* Send a request to some other service/Sensor. This request may
* update or replace the existing stream, depending on the Sensor
* specification.
*
* @param[io] data_stream Data stream on which to send the request
* @param[i] Request to be sent; Framework will copy request
*
* @return
* SNS_RC_INVALID_TYPE - Request ID not valid
* SNS_RC_INVALID_STATE - Stream is no longer available; create again
* SNS_RC_SUCCESS
*/
sns_rc (*send_request)(
sns_data_stream *data_stream,
sns_request *request);
/**
* Initiate a flush on the connection associated with sensorUID.
*
* @note This is a helper function; clients may also initiate a flush
* by generating a flush request message, and sending it via send_request.
*
* @param[io] data_stream Data stream on which to initiate the flush
*
* @return
* SNS_RC_INVALID_STATE - Stream is no longer available; create again
* SNS_RC_SUCCESS
*/
sns_rc (*initiate_flush)(
sns_data_stream *data_stream);
/**
* Retrieve a pointer to the oldest unprocessed input sample associated with
* this data stream from the event queue. This event is a single, logical
* sample, as produced and published by the source Sensor.
*
* @note Multiple sequential calls to this function will return the same
* pointer.
*
* @param[io] data_stream Data stream from which to get an event
*
* @return Next unprocessed event on the queue; NULL if no events remain
*/
sns_sensor_event* (*peek_input)(
sns_data_stream *data_stream);
/**
* Remove the current event from the input queue (the event that would
* be returned via peek_input). Return the next unprocessed event from the
* event queue.
*
* Once this function returns, there is no means to retrieve the removed
* Event again; the data has been freed, and its memory should not be
* accessed.
*
* @param[io] data_stream Data stream from which to get an event
*
* @return The next unprocessed event on the queue (after the removal occurs)
* NULL if no further events remain
*/
sns_sensor_event* (*get_next_input)(
sns_data_stream *data_stream);
/**
* Lookup the current number of input pending on this data stream. This
* value may change at any time, and should not be treated as precise.
*
* @note Do no rely on this value to assume valid input from peek_input.
*
* @param[io] data_stream Data stream from which to get the input count
*
* @return Number of input events (aka samples) available for processing
*/
uint32_t (*get_input_cnt)(
sns_data_stream *data_stream);
} sns_data_stream_api;
上面注释很清楚了，不再解释。
第一次很定进入state->fw_stream==NULL，通过获取sns_service_manager获取sns_service_type为SNS_STREAM_SERVICE的stream_service。并通过stream_service来创建一个新的sensor stream。
No.b中：接着会进入state->fw_stream != NULL，这里比较重要的是：会填充一个sns_suid_req，并通过pb_encode_request函数编码成buffer，然后继续填充sns_request，最后，通过state->fw_stream->api->send_request发送改message_id为SNS_SUID_MSGID_SNS_SUID_REQ的sns_request。后面不用说也可以知道，通过SNS_SUID_MSGID_SNS_SUID_EVENT接收的event，获取suid。不信，你可以看lsm6dso_sensor_notify_event中lsm6dso_process_suid_events函数。就是对SNS_SUID_MSGID_SNS_SUID_EVENT进行处理的。后面再详细介绍。
Ok，lsm6dso_accel_init解析完毕。
（注：这里为什么要详细介绍这部分，因为这部分是sensor driver 发送suid request的一个例子，所有sensor包括物理和虚拟sensor都会通过该种方式发送request的，并通过callback来解析event）
发送完suid request后，通过.notify_event来对返回的suid event进行解码：
static sns_rc lsm6dso_sensor_notify_event(sns_sensor *const this)
{
sns_rc rv = SNS_RC_SUCCESS;
lsm6dso_state *state = (lsm6dso_state*)this->state->state; //No.1
if((NULL != state->fw_stream &&
0 != state->fw_stream->api->get_input_cnt(state->fw_stream)) ||
(NULL != state->reg_data_stream &&
0 != state->reg_data_stream->api->get_input_cnt(state->reg_data_stream))) //No.2
{
lsm6dso_exit_island(this);
lsm6dso_process_suid_events(this);
rv = lsm6dso_process_registry_events(this);
}
if(rv == SNS_RC_SUCCESS)
{
rv = lsm6dso_process_timer_events(this); //No.3
}
if(rv == SNS_RC_SUCCESS && LSM6DSO_ACCEL == state->sensor)
{ //No.4
if(!state->hw_is_present &&
NULL != state->pwr_rail_service &&
NULL != state->timer_stream &&
state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_NONE)
{
sns_time timeticks;
state->rail_config.rail_vote = SNS_RAIL_ON_LPM;
state->pwr_rail_service->api->sns_vote_power_rail_update(state->pwr_rail_service,
this,
&state->rail_config,
&timeticks); /* ignored */
timeticks = sns_convert_ns_to_ticks(LSM6DSO_OFF_TO_IDLE_MS * 1000 * 1000);
lsm6dso_start_power_rail_timer(this, timeticks, LSM6DSO_POWER_RAIL_PENDING_INIT);
}
if(!state->available && state->hw_is_present && state->outstanding_reg_requests == 0)
{
lsm6dso_exit_island(this);
lsm6dso_update_siblings(this);
}
}
return rv;
}
No.1中获取lsm6dso_state
No.2中lsm6dso_exit_island先退出island，lsm6dso_process_suid_events来处理suid event。
void lsm6dso_process_suid_events(sns_sensor *const this)
{
lsm6dso_state *state = (lsm6dso_state*)this->state->state; //No.a
sns_data_stream *stream = state->fw_stream;
sns_service_manager *service_mgr;
sns_stream_service *stream_svc;
if(NULL == stream || 0 == stream->api->get_input_cnt(stream))
{
return;
}
service_mgr = this->cb->get_service_manager(this);
stream_svc = (sns_stream_service*) service_mgr->get_service(service_mgr,
SNS_STREAM_SERVICE);
for(sns_sensor_event *event = stream->api->peek_input(stream); //No.b
NULL != event;
event = stream->api->get_next_input(stream))
{
if(SNS_SUID_MSGID_SNS_SUID_EVENT == event->message_id)
{
sns_diag_service* diag = state->diag_service; //No.c
pb_istream_t pbstream = pb_istream_from_buffer((void*)event->event, event->event_len);
sns_suid_event suid_event = sns_suid_event_init_default;
pb_buffer_arg data_type_arg = { .buf = NULL, .buf_len = 0 };
sns_sensor_uid uid_list;
sns_suid_search suid_search;
suid_search.suid = &uid_list;
suid_search.num_of_suids = 0;
suid_event.data_type.funcs.decode = &pb_decode_string_cb;
suid_event.data_type.arg = &data_type_arg;
suid_event.suid.funcs.decode = &pb_decode_suid_event;
suid_event.suid.arg = &suid_search;
if(!pb_decode(&pbstream, sns_suid_event_fields, &suid_event)) //No.d
{
DBG_PRINT(diag, this, ERROR, __FILENAME__, __LINE__, "pb_decode() failed");
continue;
}
/* if no suids found, ignore the event */
if(suid_search.num_of_suids == 0)
{
continue;
}
/* save suid based on incoming data type name */
if(0 == strncmp(data_type_arg.buf, "interrupt", data_type_arg.buf_len))
{
state->irq_suid = uid_list;
}
else if(0 == strncmp(data_type_arg.buf, "timer", data_type_arg.buf_len))
{
state->timer_suid = uid_list;
stream_svc->api->create_sensor_stream(stream_svc, this, state->timer_suid,
&state->timer_stream);
if(NULL == state->timer_stream)
{
DBG_PRINT(diag, this, ERROR, __FILENAME__, __LINE__,
"process_suid_events:: Failed to create timer stream");
}
}
else if (0 == strncmp(data_type_arg.buf, "async_com_port",
data_type_arg.buf_len))
{
state->acp_suid = uid_list;
}
else if (0 == strncmp(data_type_arg.buf, "registry", data_type_arg.buf_len))
{
process_registry_suid(this, &uid_list);
}
else if (0 == strncmp(data_type_arg.buf, "data_acquisition_engine",
data_type_arg.buf_len))
{
state->dae_suid = uid_list;
}
else
{
DBG_PRINT(diag, this, ERROR, __FILENAME__, __LINE__,
"process_suid_events:: invalid datatype_name");
}
}
}
return;
}
上面为lsm6dso_process_suid_events函数，所有处理event的函数都与此类似。
No.a中：获取lsm6dso_state、sns_data_stream、sns_service_manager、sns_stream_service。
No.b中：比较重要，for循环去获取sns_data_stream中的event。
另一种写法：
sns_sensor_event *event = stream->api->peek_input(stream);
while(NULL != event)
{
if(SNS_SUID_MSGID_SNS_SUID_EVENT == event->message_id)
{
..............
}
...........
}
event = stream->api->get_next_input(stream);
No.c中：针对event->message_id = SNS_SUID_MSGID_SNS_SUID_EVENT的处理。
通过pb_istream_from_buffer函数从event中获取pb_istream_t，然后将pb_istream_t解码成suid_event形式。
suid_event即为我们熟知的格式。
suid_event有两个解码函数：pb_decode_string_cb用来解码data_type；pb_decode_suid_event用来解码suid。
typedef struct _sns_suid_event {
pb_callback_t data_type;
pb_callback_t suid;
/* @@protoc_insertion_point(struct:sns_suid_event) */
} sns_suid_event;
No.d中：解码后，根据data_type进行相应的处理，可以看到在该driver的.notify_event中只处理interrupt、timer、async_com_port、registry、data_acquisition_engine这几类sensor。
回到lsm6dso_sensor_notify_event函数中：
No.3：lsm6dso_process_timer_events来用处理message_id=lsm6dso_process_timer_events的event。
static sns_rc lsm6dso_process_timer_events(sns_sensor *const this)
{
...
for(sns_sensor_event *event = stream->api->peek_input(stream);
NULL != event;
event = stream->api->get_next_input(stream))
{
...
if(SNS_TIMER_MSGID_SNS_TIMER_SENSOR_EVENT != event->message_id)
{
continue; /* not interested in other events */
}
...
if(state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_INIT) //No.a
{
/** Initial HW discovery is OK to run in normal mode. */
lsm6dso_exit_island(this);
lsm6dso_discover_hw(this);
}
else if(state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_SET_CLIENT_REQ) //No.b
{
sns_sensor_instance *instance = sns_sensor_util_get_shared_instance(this);
if(NULL != instance)
{
...
inst_state->instance_is_ready_to_configure = true;
lsm6dso_reval_instance_config(this, instance, state->sensor);
}
}
else if(state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_OFF) //No.c
{
sns_sensor_instance *instance = sns_sensor_util_get_shared_instance(this);
state->rail_config.rail_vote = SNS_RAIL_OFF;
state->pwr_rail_service->api->
sns_vote_power_rail_update(state->pwr_rail_service, this,
&state->rail_config, NULL);
if(NULL != instance)
{
lsm6dso_instance_state *inst_state = (lsm6dso_instance_state*) instance->state->state;
inst_state->instance_is_ready_to_configure = false;
}
}
sns_sensor_util_remove_sensor_stream(this, &state->reg_data_stream);
state->power_rail_pend_state = LSM6DSO_POWER_RAIL_PENDING_NONE;
}
if(state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_NONE) //No.d
{
sns_sensor_util_remove_sensor_stream(this, &state->timer_stream);
}
return rv;
}
该函数中处理完timer event后，根据不同的state->power_rail_pend_state做不同的操作，
No.a是：当state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_INIT时，执行退出island，discover_hw，discover_hw中，读芯片register来判断是哪颗芯片：
void lsm6dso_discover_hw(sns_sensor *const this)
{
sns_rc rv = SNS_RC_SUCCESS;
...
/**-------------------Read and Confirm WHO-AM-I------------------------*/
buffer[0] = 0x0;
...
rv = lsm6dso_get_who_am_i(state->scp_service,state->com_port_info.port_handle, &buffer[0]);
...
if(rv == SNS_RC_SUCCESS
&&
buffer[0] == LSM6DSO_WHOAMI_VALUE)
{
...
sns_sensor_instance *instance = sns_sensor_util_get_shared_instance(this);
if(instance)
{
...
// Reset Sensor
rv = lsm6dso_reset_device(instance,
LSM6DSO_ACCEL | LSM6DSO_GYRO | LSM6DSO_MOTION_DETECT | LSM6DSO_SENSOR_TEMP);
if(rv == SNS_RC_SUCCESS)
{
state->hw_is_present = true;
}
}
...
}
...
state->who_am_i = buffer[0];
/**------------------Power Down and Close COM Port--------------------*/
state->scp_service->api->sns_scp_update_bus_power(state->com_port_info.port_handle,
false);
state->scp_service->api->sns_scp_close(state->com_port_info.port_handle);
state->scp_service->api->sns_scp_deregister_com_port(&state->com_port_info.port_handle);
/**----------------------Turn Power Rail OFF--------------------------*/
state->rail_config.rail_vote = SNS_RAIL_OFF;
state->pwr_rail_service->api->sns_vote_power_rail_update(state->pwr_rail_service,
this,
&state->rail_config,
NULL);
}
可以看到通过lsm6dso_get_who_am_i来获取芯片信息后，再reset device，reset无论成功与否，都要close COM port，通过sns_vote_power_rail_update来关电。这部分code会在系统初始化的时候跑一遍。
No.b：state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_SET_CLIENT_REQ时，会通过函数lsm6dso_reval_instance_config发送配置信息。
No.c：state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_OFF，顾名思义——关电。并remove registry data sream。
No.d：state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_NONE时直接remove timer data stream。
回到lsm6dso_sensor_notify_event中：
No.4：主要是在lsm6dso_start_power_rail_timer中发送timer的request，来控制power rail。注意：
先将state->rail_config.rail_vote 设为SNS_RAIL_ON_LPM（这种state只用在accel driver上），然后sns_vote_power_rail_update进入low power mode。然后通过lsm6dso_start_power_rail_timer发送timer的request，
注意：pwr_rail_pend_state = LSM6DSO_POWER_RAIL_PENDING_INIT，这就与上面的No.a对应起来，会discover hw，然后再关电。
（2）init对应的是deinit
sns_rc lsm6dso_accel_deinit(sns_sensor *const this)
{
UNUSED_VAR(this);
// Turn Sensor OFF.
// Close COM port.
// Turn Power Rails OFF.
// No need to clear lsm6dso_state because it will get freed anyway.
return SNS_RC_SUCCESS;
}
（3）lsm6dso_get_sensor_uid函数，用来获取suid。
sns_sensor_uid const* lsm6dso_get_sensor_uid(sns_sensor const *const this)
{
lsm6dso_state *state = (lsm6dso_state*)this->state->state;
return &state->my_suid;
}
sensor driver初始化流程如下图：
Ok，初始化是每个sensor driver一开跑的code，通过初始化可以获取hardware信息，初始化系统资源，解析registry config等等，为sensor driver 下一步Activation提供了可靠的保障。
Activation：
（4）lsm6dso_set_client_request函数，用来设置来自client的request。并创建sensor instance。
set_client_request函数的解释如下：
该函数是用来add、remove、update来自client的request。
如果remove为true：通过sns_sensor_instance_cb::remove_client_request来删除这个client，并重排来自client的request和sensor_instances。
如果remove设为false：分为两种处理方式：i，若是一个new request ； ii，若是一个已经存在的request。
可以看到在sns_stream_service.c的handle_req中，set_client_request的remove参数为false的。在handle_stream_destroy中，set_client_request的remove参数为true。
下面分步解析lsm6dso_set_client_request的code。
sns_sensor_instance* lsm6dso_set_client_request(sns_sensor *const this,
struct sns_request const *exist_request,
struct sns_request const *new_request,
bool remove)
{
lsm6dso_state *state = (lsm6dso_state*)this->state->state;
sns_sensor_instance *instance = sns_sensor_util_get_shared_instance(this); //No.1
sns_diag_service* diag = state->diag_service; sns_time on_timestamp;
sns_time delta;
bool reval_config = false;
...
No.1中通过sns_sensor_util_get_shared_instance来查找sensor共享的instance。许多物理sensor共享一个单独instance，通过该函数查找该instance，若存在，则返回该instance；若不存在，则返回NULL。
if(remove)
{
if(NULL == instance) { //No.2
DBG_PRINT(diag, this, ERROR, __FILENAME__, __LINE__,
"lsm6dso_set_client_request:: Instance not available! Returning!");
return instance;
}
...
lsm6dso_instance_state *inst_state =
(lsm6dso_instance_state*)instance->state->state;
inst_state->config_sensors |= state->sensor;
instance->cb->remove_client_request(instance, exist_request); //No.3
if(exist_request->message_id != SNS_PHYSICAL_SENSOR_TEST_MSGID_SNS_PHYSICAL_SENSOR_TEST_CONFIG) //No.4
{
lsm6dso_reval_instance_config(this, instance, state->sensor);
}
else //No.5
{
lsm6dso_instance_state *inst_state =
(lsm6dso_instance_state*)instance->state->state;
...
//If a factory self test was run, update the registry & sensor->state
if(inst_state->self_test_info.update_registry)
{
DBG_PRINT(diag, this, MED, __FILENAME__, __LINE__,
"Updating registry and sensor state with new calibration values");
//copy to sensor state
if(LSM6DSO_ACCEL == inst_state->self_test_info.sensor)
{
sns_memscpy(state->fac_cal_bias, sizeof(state->fac_cal_bias),
inst_state->accel_registry_cfg.fac_cal_bias, sizeof(inst_state->accel_registry_cfg.fac_cal_bias));
}
else if(LSM6DSO_GYRO == inst_state->self_test_info.sensor)
{
sns_memscpy(state->fac_cal_bias, sizeof(state->fac_cal_bias),
inst_state->gyro_registry_cfg.fac_cal_bias, sizeof(inst_state->gyro_registry_cfg.fac_cal_bias));
}
//Update flag in sensor_state to indicate which registry is to be updated
//write registry
inst_state->registry_reset.request = false;
lsm6dso_sensor_write_output_to_registry(this, instance);
// Set the flag to false indicating that the registry is updated
inst_state->self_test_info.update_registry = false;
}
}
}
在分析remove这路前，先了解下sns_sensor_instance中的sns_sensor_instance_cb的callback函数吧，下面我们介绍了sns_sensor中的sns_sensor_cb callback函数。
//sns_sensor_instance.h
typedef struct sns_sensor_instance
{
/* Functions which call back into the framework; provided by the Framework */
struct sns_sensor_instance_cb const *cb;
/* State space allocated by the Framework for the sole use of the Sensor
* Instance developer. */
struct sns_sensor_instance_state *state;
} sns_sensor_instance;
//sns_sensor_instance.h
typedef struct sns_sensor_instance_cb
{
uint32_t struct_len;
/**
* Get a reference to the Service Manager. With this object, a reference
* to any other utility service can be obtained.
*
* @param[i] this Sensor Instance reference
*
* @return Service Manager reference
*/
struct sns_service_manager* (*get_service_manager)(
sns_sensor_instance *this);
/**
* Return the next client request associated with this Sensor Instance and
* SUID.
*
* Each Sensor Instance has a list of client requests per SUID which it is
* servicing. Entries are added via calls to add_client_request; removed
* via remove_client_request.
*
* Each call to this function iterates over the list, and returns the next
* entry. NULL is returned at the end of the list, or if the list is empty.
*
* @note An Instance may be handling client requests for multiple
* (related) Sensors; must use SUID parameter to filter.
*
* @param[i] this Sensor Instance reference
* @param[i] suid Sensor associated with this Instance
* @param[i] first Return the first request; reset the internal iterator
* Must be called first to initialize iteration
*
* SNS_RC_NOT_AVAILABLE - The Framework is not aware of SUID
* SNS_RC_SUCCESS
*/
struct sns_request const* (*get_client_request)(
sns_sensor_instance *this,
sns_sensor_uid const *suid,
bool first);
/**
* Remove a client request from this Sensor Instance.
*
* @param[i] this Sensor Instance reference
* @param[i] request Client request to be removed
*/
void (*remove_client_request)(
sns_sensor_instance *this,
struct sns_request const *request);
/**
* Assign this Sensor Instance to service the client request.
*
* @note This function may only be given sns_request objects received
* from sns_sensor_api::set_client_request.
*
* @note The SUID of the recepient Sensor will be noted upon addition;
* this SUID must be used within get_client_request.
*
* @param[i] this Sensor Instance reference
* @param[i] request Client request to be added
*/
void (*add_client_request)(
sns_sensor_instance *this,
struct sns_request const *request);
} sns_sensor_instance_cb;
四个函数分别如下：
然后就可以继续分析remove这路的代码了。
No.2：在remove instance时，若instance为NULL，instance都为NULL了还remove什么呀，直接return NULL。
No.3：当instance不为NULL时，执行instance->cb->remove_client_request(instance, exist_request)，remove一个client request，当然这个client request是exist_requset是旧的request。
No.4：然后判断旧的request的message_id即exist_request->message_id是否为SNS_PHYSICAL_SENSOR_TEST_MSGID_SNS_PHYSICAL_SENSOR_TEST_CONFIG；若不为，则会通过lsm6dso_reval_instance_config函数发送所有的HW Resources给instance，做最后的处理。因为，一旦走到remove分支，framework将调用instance中的deinit()来摧毁该instance，在调deinit()前需要将所有的Hw资源发送给instance，以便让deinit()摧毁。这样摧毁的才更彻底。
No.5：走为SNS_PHYSICAL_SENSOR_TEST_MSGID_SNS_PHYSICAL_SENSOR_TEST_CONFIG这路，说明正在做self-test，首先判断是否reconfig_postpone是否为true，若为true，说明在self-test时有延缓重新配置configure的需求（reconfigure），那不用说了，都要摧毁instance了，现在还不做，什么时候做呀，于是Do it now。即执行lsm6dso_reval_instance_config函数。
接着，就开始写registry了，若update_registry为true，说明factory self test在运行，Ok，不要运行了，可以结束了，赶紧写registry。于是通过lsm6dso_sensor_write_output_to_registry函数将accel calibration的数据accel_registry_cfg.fac_cal_bias、gyro calibration的数据gyro_registry_cfg.fac_cal_bias写入/persisit/sensors/registry/registry/lsm6dso_0_platform.accel.fac_cal和lsm6dso_0_platform.gyro.fac_cal中以便以后使用。
#define LSM6DSO_REG_PLATFORM_FAC_CAL_ACCEL "lsm6dso_0_platform.accel.fac_cal"
#define LSM6DSO_REG_PLATFORM_FAC_CAL_GYRO "lsm6dso_0_platform.gyro.fac_cal"
bool lsm6dso_sensor_write_output_to_registry(
sns_sensor *const this,
sns_sensor_instance *const instance)
{
...
char accel_name[] = LSM6DSO_REG_PLATFORM_FAC_CAL_ACCEL;
char gyro_name[] = LSM6DSO_REG_PLATFORM_FAC_CAL_GYRO;
sns_registry_write_req write_req = sns_registry_write_req_init_default;
...
if(((inst_state->self_test_info.sensor == LSM6DSO_ACCEL) && !(inst_state->registry_reset.request)) || ((inst_state->registry_reset.sensor_type == LSM6DSO_ACCEL) && (inst_state->registry_reset.request)))
{
name_data = (pb_buffer_arg)
{ .buf = accel_name, .buf_len = strlen(accel_name) + 1 };
}
...
write_req.name.funcs.encode = &pb_encode_string_cb;
write_req.name.arg = &name_data;
write_req.data.items.funcs.encode = &sns_send_to_registry_persist_cb;
write_req.data.items.arg = instance;
...
encoded_len = pb_encode_request(buffer, sizeof(buffer),
&write_req, sns_registry_write_req_fields, NULL);
if(0 < encoded_len)
{
sns_request request = (sns_request){
.request_len = encoded_len, .request = buffer,
.message_id = SNS_REGISTRY_MSGID_SNS_REGISTRY_WRITE_REQ };
state->reg_data_stream->api->send_request(state->reg_data_stream, &request);
}
return true;
}
因为这是demo code，所以写的比较复杂，在正常情况下没有那么繁琐，如下即可。
if(remove)
{
if(NULL != instance)
{
instance->cb->remove_client_request(instance, exist_request);
xxxx_reval_instance_config(this, instance, state->sensor);
if(exist_request->message_id == SNS_PHYSICAL_SENSOR_TEST_MSGID_SNS_PHYSICAL_SENSOR_TEST_CONFIG)
{
/** Write bias into registry when client was removed */
if(inst_state->update_fac_cal_in_registry)
{
...
xxxxx_update_registry(this, instance, sensor_type);
inst_state->update_fac_cal_in_registry = false;
}
}
}
}
remove分析完了，下面分析else分支：else分支分为两个一个是instance ！= NULL、另一个是instance == NULL。下面code可以说目前不属于任何分支，只是一个小小的过滤。
else
{
if(NULL != instance) //No.6
{
lsm6dso_instance_state *inst_state =
(lsm6dso_instance_state*)instance->state->state;
if(inst_state->self_test_info.test_alive)
{
DBG_PRINT(diag, this, HIGH, __FILENAME__, __LINE__,
"Self test is running. Ignoring new request! ");
return NULL; // Return without honouring any request for any sensor streaming
}
No.6中：若instance != NULL，并且self_test_info.test_alive == true，说明目前正处于self-test，Ok，任何request都忽略。即return NULL。该段code过滤掉所有在self-test中的请求，这样不会打断factory calibration。
下面开始正式处理两个分支了。先分析instance == NULL的情况。
if(NULL == instance)
{
if(state->sensor == LSM6DSO_GYRO) //No.7
{
state->rail_config.rail_vote = SNS_RAIL_ON_NPM;
}
else
{
state->rail_config.rail_vote = SNS_RAIL_ON_LPM;
}
state->pwr_rail_service->api->sns_vote_power_rail_update(
state->pwr_rail_service,
this,
&state->rail_config,
&on_timestamp);
delta = sns_get_system_time() - on_timestamp; //No.8
// Use on_timestamp to determine correct Timer value.
if(delta < sns_convert_ns_to_ticks(LSM6DSO_OFF_TO_IDLE_MS*1000*1000))
{
DBG_PRINT(diag, this, MED, __FILENAME__, __LINE__,
"lsm6dso_set_client_request:: start power rail timer");
lsm6dso_start_power_rail_timer(this,
sns_convert_ns_to_ticks(LSM6DSO_OFF_TO_IDLE_MS*1000*1000) - delta,
LSM6DSO_POWER_RAIL_PENDING_SET_CLIENT_REQ);
} else {
// rail is already ON
state->power_rail_pend_state = LSM6DSO_POWER_RAIL_PENDING_NONE;
reval_config = true;
}
/** create_instance() calls init() for the Sensor Instance */ //No.9
instance = this->cb->create_instance(this,
sizeof(lsm6dso_instance_state));
/* If rail is already ON then flag instance OK to configure */
if(reval_config)
{
lsm6dso_instance_state *inst_state =
(lsm6dso_instance_state*)instance->state->state;
inst_state->instance_is_ready_to_configure = true;
}
}
这路比较简单，
因为instance == NULL，所有要创建一个新的instance。
No.7：因为accel可以工作在low power mode下，所有和gyro有区分。然后通过sns_vote_power_rail_update 改变上电状态。
No.8：sns_get_system_time获取系统的滴答时间，获取系统时间戳和上电时的时间戳的差值delta。若差值小于100ms，说明没有上电，于是通过lsm6dso_start_power_rail_timer上电。若差值大于100ms，说明已经上电，设置state->power_rail_pend_state为LSM6DSO_POWER_RAIL_PENDING_NONE。
值得一提的是：lsm6dso_start_power_rail_timer会发送request，可以通过lsm6dso_sensor_notify_event中的lsm6dso_process_timer_events函数接收（前面已经介绍过该函数）。lsm6dso_process_timer_events中进入state->power_rail_pend_state == LSM6DSO_POWER_RAIL_PENDING_SET_CLIENT_REQ的分支进行reconfig操作。
No.9：上电后，开始创建新的instance。reval_config被设为true时（即rail is already ON的情况），设置inst_state->instance_is_ready_to_configure = true；若不是rail is already ON的情况呢，不用担心，会走上面斜体标记的lsm6dso_process_timer_events部分，在if中，instance_is_ready_to_configure还是被设成true的。
再分析instance ！= NULL的情况，在不为NULL的情况下，还分为两部分：一部分是exist_requst & new_request均不为NULL，即新旧request均不为NULL 和new_requset ->message_id == SNS_STD_MSGID_SNS_STD_FLUSH_REQ。另一部分，则为else。分为No.10 和 No.11来讲。
else
{
...
if(NULL != exist_request //No.10
&&
NULL != new_request
&&
new_request->message_id == SNS_STD_MSGID_SNS_STD_FLUSH_REQ)
{
lsm6dso_instance_state *inst_state =
(lsm6dso_instance_state*)instance->state->state;
if(inst_state->fifo_info.fifo_enabled &&
((state->sensor == LSM6DSO_ACCEL) || (state->sensor == LSM6DSO_GYRO)))
{
lsm6dso_send_flush_config(this, instance);
/** Do not update instance client request list at this point
because FIFO flush is a transitory request for an on-going
stream request. */
return instance;
}
else
{
/** There aren't any FIFO sensors enabled to support flush.
* Send flush complete event anyway. */
lsm6dso_send_fifo_flush_done(instance, &state->my_suid);
return instance;
}
}
else //No.11
{
reval_config = true;
/** An existing client is changing request*/
if((NULL != exist_request) && (NULL != new_request))
{
instance->cb->remove_client_request(instance, exist_request);
}
/** A new client sent new_request*/
else if(NULL != new_request)
{
// No-op. new_request will be added to requests list below.
}
}
}
No.10：处理new_request->message_id == SNS_STD_MSGID_SNS_STD_FLUSH_REQ，若fifo_enable为true。则通过lsm6dso_send_flush_config，通过this->instance_api->set_client_config发送message_id = SNS_STD_MSGID_SNS_STD_FLUSH_REQ的request。若else：则说明fifo 不是enable的，则通过lsm6dso_send_fifo_flush_done直接flush。通过event_service->api->publish_event
发送message_id = SNS_STD_MSGID_SNS_STD_FLUSH_EVENT的flush event。
No.11：若不满足上面的任意一种的情况下，if exist_request & new_request均不为NULL，即只有message_id ！= SNS_STD_MSGID_SNS_STD_FLUSH_REQ，通过instance->cb->remove_client_request函数remove掉exist_requset，即remove掉存在的request。 else if 没有进行操作。下面再进行操作。
接着在分析instance != NULL的情况。为甚么用写一遍instance != NULL呢？因为上面若instance == NULL时，创建instance后，instance就不为NULL了，这时就要处理instance != NULL的情况。当前，实际写code时，可以省略不少步骤。
{
lsm6dso_instance_state *inst_state =
(lsm6dso_instance_state*)instance->state->state;
if(NULL != new_request) //No.12
{
instance->cb->add_client_request(instance, new_request);
if(LSM6DSO_MOTION_DETECT == state->sensor) {
sns_memscpy(&inst_state->md_info.md_config, sizeof(inst_state->md_info.md_config),
&state->md_config, sizeof(state->md_config));
DBG_PRINT(diag, this, HIGH, __FILENAME__, __LINE__,
"lsm6dso_set_client_request:: copying md config");
}
if(new_request->message_id == SNS_STD_SENSOR_MSGID_SNS_STD_SENSOR_CONFIG //No.13
||
new_request->message_id == SNS_STD_EVENT_GATED_SENSOR_MSGID_SNS_STD_SENSOR_CONFIG) {
inst_state->config_sensors |= state->sensor;
//copy range/resolution to inst state
if(LSM6DSO_ACCEL == state->sensor)
{
inst_state->accel_info.sstvt = lsm6dso_accel_resolutions[state->resolution_idx]*1000; //convert to micro-g/LSB
inst_state->accel_info.range = lsm6dso_accel_ranges[state->resolution_idx];
inst_state->accel_info.range_idx = state->resolution_idx;
}
else if(LSM6DSO_GYRO == state->sensor)
{
inst_state->gyro_info.sstvt = lsm6dso_gyro_resolutions[state->resolution_idx];
inst_state->gyro_info.range = lsm6dso_gyro_ranges[state->resolution_idx];
inst_state->gyro_info.range_idx = state->resolution_idx;
}
}
if(new_request->message_id == SNS_CAL_MSGID_SNS_CAL_RESET) { //No.14
DBG_PRINT(diag, this, HIGH, __FILENAME__, __LINE__,
"Received event: SNS_CAL_MSGID_SNS_CAL_RESET");
inst_state->registry_reset.request = true;
inst_state->registry_reset.sensor_type = state->sensor;
lsm6dso_sensor_write_output_to_registry(this, instance);
//copy to sensor state
if(LSM6DSO_ACCEL == state->sensor)
{
sns_memscpy(state->fac_cal_bias, sizeof(state->fac_cal_bias),
inst_state->accel_registry_cfg.fac_cal_bias, sizeof(inst_state->accel_registry_cfg.fac_cal_bias));
sns_memscpy(&state->fac_cal_corr_mat, sizeof(state->fac_cal_corr_mat),
&inst_state->accel_registry_cfg.fac_cal_corr_mat, sizeof(inst_state->accel_registry_cfg.fac_cal_corr_mat));
}
else if(LSM6DSO_GYRO == state->sensor)
{
sns_memscpy(state->fac_cal_bias, sizeof(state->fac_cal_bias),
inst_state->gyro_registry_cfg.fac_cal_bias, sizeof(inst_state->gyro_registry_cfg.fac_cal_bias));
sns_memscpy(&state->fac_cal_corr_mat, sizeof(state->fac_cal_corr_mat),
&inst_state->gyro_registry_cfg.fac_cal_corr_mat, sizeof(inst_state->gyro_registry_cfg.fac_cal_corr_mat));
}
lsm6dso_send_cal_event(instance, state->sensor);
}
if(new_request->message_id == SNS_STD_SENSOR_MSGID_SNS_STD_ON_CHANGE_CONFIG //No.15
&&
state->sensor == LSM6DSO_MOTION_DETECT)
{
if(inst_state->fifo_info.publish_sensors & LSM6DSO_ACCEL) {
//send event as MD disabled since non-gated client is active
//no need of this as we alreay set md_info state
sns_motion_detect_event md_state;
md_state.motion_detect_event_type = SNS_MOTION_DETECT_EVENT_TYPE_DISABLED;
DBG_PRINT(diag, this, MED, __FILENAME__, __LINE__,
"send MD_event =%d",
md_state.motion_detect_event_type);
pb_send_event(instance,
sns_motion_detect_event_fields,
&md_state,
sns_get_system_time(),
SNS_MOTION_DETECT_MSGID_SNS_MOTION_DETECT_EVENT,
&inst_state->md_info.suid);
reval_config = false;
} else if (inst_state->md_info.enable_md_int) {
//there is exsisting md client already present, just send event
DBG_PRINT(diag, this, MED, __FILENAME__, __LINE__,
"send MD_event =%d",
inst_state->md_info.cur_md_state.motion_detect_event_type);
pb_send_event(instance,
sns_motion_detect_event_fields,
&inst_state->md_info.cur_md_state,
sns_get_system_time(),
SNS_MOTION_DETECT_MSGID_SNS_MOTION_DETECT_EVENT,
&inst_state->md_info.suid);
reval_config = false;
} else
inst_state->md_info.md_new_req = true;
}
}
if(reval_config && inst_state->instance_is_ready_to_configure) //No.16
{
lsm6dso_reval_instance_config(this, instance, state->sensor);
}
}
这部分code才是关键
No.12：new_requset != NULL为前提条件，通过add_client_request添加一个request client，以后新的request都会通过该client进行处理。
No.13：message_id = SNS_STD_SENSOR_MSGID_SNS_STD_SENSOR_CONFIG 或SNS_STD_EVENT_GATED_SENSOR_MSGID_SNS_STD_SENSOR_CONFIG进行处理，设置相应的参数。
No.14：message_id == SNS_CAL_MSGID_SNS_CAL_RESET进行处理，写registry。
No.15：message_id == SNS_STD_SENSOR_MSGID_SNS_STD_ON_CHANGE_CONFIG进行处理，on change只有motion_detect才是，所以只处理motion_detect。
No.16：跳出if(new_requset != NULL)循环，若reval_config 和 instance_is_ready_to_configure均为true，则reconfig instance参数。
Ok，到这里remove 为false的分支解析完毕，总结一下：
若instance == NULL，则创建新的instance；若instance != NULL并且新的request的messge_id为SNS_STD_MSGID_SNS_STD_FLUSH_REQ则进行flush，直接return instance；若instance != NULL并且messge_id不为SNS_STD_MSGID_SNS_STD_FLUSH_REQ，先remove旧的client_request，再创建新的client_request，再跟进新的request的message_id进行相应的处理。
lsm6dso_set_client_request最后一部分：异常处理
// Sensors are required to call remove_instance when clientless
if(NULL != instance &&
NULL == instance->cb->get_client_request(instance,
&(sns_sensor_uid)ACCEL_SUID, true) &&
NULL == instance->cb->get_client_request(instance,
&(sns_sensor_uid)MOTION_DETECT_SUID, true) &&
NULL == instance->cb->get_client_request(instance,
&(sns_sensor_uid)GYRO_SUID, true) &&
NULL == instance->cb->get_client_request(instance,
&(sns_sensor_uid)SENSOR_TEMPERATURE_SUID, true))
{
this->cb->remove_instance(instance);
}
return instance;
若出现instance !=NULL的同时，获取不同accel、motion_detect、gyro、temp的client request，则remove instance。
因为我们前进都已经add_client_request过client request了，若现在有获取不到client request了，说明中间某步出了问题，不能继续进行了，则需要remove instance。
Ok，lsm6dso_set_client_request分析完毕。
这里面需要注意下：与后续sns_sensor_instance_api有关系的地方。
sns_rc
sns_sensor_init_fw(void)
{
sensor_cb = (sns_sensor_cb)
{
...
.create_instance = &sns_sensor_instance_init,
.remove_instance = &sns_sensor_instance_deinit,
...
};
return SNS_RC_SUCCESS;
}
SNS_SECTION(".text.sns") sns_sensor_instance*
sns_sensor_instance_init(sns_sensor *sensor, uint32_t state_len)
{
sns_fw_sensor *fw_sensor = (sns_fw_sensor*)sensor;
...
rv = sensor->instance_api->init(
(sns_sensor_instance*)instance, sensor->state);
...
}
return (sns_sensor_instance*)instance;
}
下面开始介绍sns_sensor_instance_api
2： sns_sensor_instance_api定义在sns_sensor_instance.h中，结构如下：
//sns_sensor_instance.h
typedef struct sns_sensor_instance_api
{
uint32_t struct_len;
/**
* Initialize a Sensor Instance to its default state. A call to
* sns_sensor_instance_api::deinit will precede any subsequent calls
* to this function.
*
* @note Persistent configuration can be made available using the
* sensor_state.
*
* @param[i] this Sensor Instance reference
* @param[i] sensor_state State of the Sensor which created this Instance
*
* @return
* SNS_RC_NOT_AVAILABLE - Sensor state does not allow for this operation
* SNS_RC_SUCCESS
*/
sns_rc (*init)(
sns_sensor_instance *const this,
sns_sensor_state const *sensor_state);
/**
* Release all hardware and software resources associated with this Sensor
* Instance.
*
* @param[i] this Sensor Instance reference
*
* @return
* SNS_RC_INVALID_STATE - Error occurred: some resource could not be released
* SNS_RC_SUCCESS
*/
sns_rc (*deinit)(
sns_sensor_instance *const this);
/**
* Update a Sensor Instance configuration to this sensorRequest.
*
* The Sensor Instance is expected to start all dependent streams, timers, etc..
*
* @note
* A Sensor may define any number of unique request types they support.
* However, a client may only have a single active stream; an enable
* request can inherently serve as a "reconfiguration" request.
*
* @param[i] this Sensor Instance reference
*
* @return
* SNS_RC_INVALID_VALUE - Invalid client request
* SNS_RC_SUCCESS
*/
sns_rc (*set_client_config)(
sns_sensor_instance *const this,
struct sns_request const *client_request);
/**
* Notification to the client that some data has been received.
*
* The client must use the sns_manager_event to obtain this data
* for processing.
*
* @return
* SNS_RC_INVALID_STATE - A client error occurred; Framework shall destroy client
* SNS_RC_NOT_AVAILABLE - A transitory error occurred; Framework shall remove
* all outstanding input
* SNS_RC_SUCCESS
*/
sns_rc (*notify_event)(
sns_sensor_instance *const this);
} sns_sensor_instance_api;
上面每个函数都有注释，这里不再解释。
sns_rc lsm6dso_inst_init(sns_sensor_instance *const this,
sns_sensor_state const *sstate)
{
state->scp_service = (sns_sync_com_port_service*)
service_mgr->get_service(service_mgr, SNS_SYNC_COM_PORT_SERVICE);
/**---------Setup stream connections with dependent Sensors---------*/
stream_mgr->api->create_sensor_instance_stream(stream_mgr,
this,
sensor_state->irq_suid,
&state->interrupt_data_stream);
stream_mgr->api->create_sensor_instance_stream(stream_mgr,
this,
sensor_state->acp_suid,
&state->async_com_port_data_stream);
在lsm6dso_inst_init中多数为初始化设置，包含获取sync_com_port service和创建async_com_port&interrupt data stream。
state->scp_service->api->sns_scp_register_com_port(&state->com_port_info.com_config,
&state->com_port_info.port_handle);
通过instance注册com port。
在instance state复制所有sensor uids，初始化FIFO状态，初始Accel状态，初始Gyro状态等等，初始化中断数据，初始化com config，enable async com port：
/** Configure the Async Com Port */
{
sns_data_stream* data_stream = state->async_com_port_data_stream;
uint8_t pb_encode_buffer[100];
sns_request async_com_port_request =
{
.message_id = SNS_ASYNC_COM_PORT_MSGID_SNS_ASYNC_COM_PORT_CONFIG,
.request = &pb_encode_buffer
};
async_com_port_request.request_len =
pb_encode_request(pb_encode_buffer,
sizeof(pb_encode_buffer),
&state->ascp_config,
sns_async_com_port_config_fields,
NULL);
data_stream->api->send_request(data_stream, &async_com_port_request);
}
等等。。。
对应的是lsm6dso_inst_deinit
sns_rc lsm6dso_inst_deinit(sns_sensor_instance *const this)
{
lsm6dso_instance_state *state =
(lsm6dso_instance_state*)this->state->state;
inst_cleanup(this, state);
return SNS_RC_SUCCESS;
}
static void inst_cleanup(sns_sensor_instance *const this,
lsm6dso_instance_state *state)
{
...
if(NULL != state->com_port_info.port_handle)
{
state->scp_service->api->sns_scp_update_bus_power(state->com_port_info.port_handle, true);
}
lsm6dso_set_fifo_config(this, 0, 0, 0, 0 );
lsm6dso_reconfig_hw(this);
if(NULL != state->com_port_info.port_handle)
{
state->scp_service->api->sns_scp_update_bus_power(state->com_port_info.port_handle, false);
}
sns_sensor_util_remove_sensor_instance_stream(this, &state->interrupt_data_stream);
sns_sensor_util_remove_sensor_instance_stream(this, &state->async_com_port_data_stream);
sns_sensor_util_remove_sensor_instance_stream(this, &state->timer_sensor_temp_data_stream);
sns_sensor_util_remove_sensor_instance_stream(this, &state->timer_md_data_stream);
sns_sensor_util_remove_sensor_instance_stream(this, &state->timer_self_test_data_stream);
sns_sensor_util_remove_sensor_instance_stream(this, &state->timer_heart_beat_data_stream);
if(NULL != state->scp_service)
{
state->scp_service->api->sns_scp_close(state->com_port_info.port_handle);
state->scp_service->api->sns_scp_deregister_com_port(&state->com_port_info.port_handle);
state->scp_service = NULL;
}
lsm6dso_dae_if_deinit(this);
}
inst_cleanup中：
下面解析sns_sensor_instance_api::set_client_config
static sns_rc lsm6dso_inst_set_client_config(sns_sensor_instance *const this,
sns_request const *client_request)
{
lsm6dso_instance_state *state =
(lsm6dso_instance_state*)this->state->state;
...
sns_service_manager *mgr = this->cb->get_service_manager(this);
sns_event_service *e_service = (sns_event_service*)mgr->get_service(mgr, SNS_EVENT_SERVICE); //No.1
sns_lsm6dso_req *payload = (sns_lsm6dso_req*)client_request->request;
...
// Turn COM port ON
state->scp_service->api->sns_scp_update_bus_power(state->com_port_info.port_handle, //No.2
true);
// Register for interrupt
if(!lsm6dso_dae_if_available(this)) //No.3
{
lsm6dso_register_interrupt(this);
}
该段code中首先
No.1：获取sns_service_manager ，并通过sns_service_manager 获取sns_event_service。
No.2：通过sns_scp_update_bus_power给COM port上电。
No.3：先判断sensor dae_if是否enable，若enable，则可以使用中断采集数据。接着，注册interrupt，在lsm6dso_register_interrupt函数中，发送message_id = SNS_INTERRUPT_MSGID_SNS_INTERRUPT_REQ的request来请求interrupt。
下面针对不同message_id进行处理。
if(client_request->message_id == SNS_STD_SENSOR_MSGID_SNS_STD_SENSOR_CONFIG)
{
desired_sample_rate = payload->desired_sample_rate; //No.4
desired_report_rate = payload->desired_report_rate;
uint8_t desired_rate_idx = 0;
if(state->fifo_info.fifo_enabled & LSM6DSO_ACCEL) //No.5
{
rv = lsm6dso_match_odr(LSM6DSO_ACCEL, desired_sample_rate,
&desired_rate_idx,
&accel_chosen_sample_rate,
&accel_chosen_sample_rate_reg_value,
&accel_num_samples_to_discard);
}
if(state->fifo_info.fifo_enabled & LSM6DSO_GYRO) //No.6
{
rv = lsm6dso_match_odr(LSM6DSO_GYRO, desired_sample_rate,
&desired_rate_idx,
&gyro_chosen_sample_rate,
&gyro_chosen_sample_rate_reg_value,
&gyro_num_samples_to_disca