[posix] extract co-processor init out of otSysInit (#10344)

This commit adds a new posix sys API `otSysInitCoprocessor` which only
initializes the platform spinel component. (Reset the co-processor and
get the type)

The intention is to let the app to get the co-processor type without
creating the otInstance. Currently only `otSysInit` can be called
which creates the otInstance. However in some cases, we don't want to
create the instance at the early stage.

src/posix/main.c

@@ -275,12 +275,14 @@ static void ParseArg(int aArgCount, char *aArgVector[], PosixConfig *aConfig)
 
     for (; optind < aArgCount; optind++)
     {
-        VerifyOrDie(aConfig->mPlatformConfig.mRadioUrlNum < OT_ARRAY_LENGTH(aConfig->mPlatformConfig.mRadioUrls),
+        VerifyOrDie(aConfig->mPlatformConfig.mCoprocessorUrls.mNum <
+                        OT_ARRAY_LENGTH(aConfig->mPlatformConfig.mCoprocessorUrls.mUrls),
                     OT_EXIT_INVALID_ARGUMENTS);
-        aConfig->mPlatformConfig.mRadioUrls[aConfig->mPlatformConfig.mRadioUrlNum++] = aArgVector[optind];
+        aConfig->mPlatformConfig.mCoprocessorUrls.mUrls[aConfig->mPlatformConfig.mCoprocessorUrls.mNum++] =
+            aArgVector[optind];
     }
 
-    if (aConfig->mPlatformConfig.mRadioUrlNum == 0)
+    if (aConfig->mPlatformConfig.mCoprocessorUrls.mNum == 0)
     {
         PrintUsage(aArgVector[0], stderr, OT_EXIT_INVALID_ARGUMENTS);
     }

src/posix/platform/include/openthread/openthread-system.h

@@ -69,25 +69,49 @@ enum
     OT_PLATFORM_CONFIG_MAX_RADIO_URLS = 2, ///< Max number of Radio URLs.
 };
 
+/**
+ * Represents the Co-processor URLs.
+ *
+ */
+typedef struct otPlatformCoprocessorUrls
+{
+    const char *mUrls[OT_PLATFORM_CONFIG_MAX_RADIO_URLS]; ///< Co-processor URLs.
+    uint8_t     mNum;                                     ///< Number of Co-processor URLs.
+} otPlatformCoprocessorUrls;
+
 /**
  * Represents platform specific configurations.
  *
  */
 typedef struct otPlatformConfig
 {
-    const char *mBackboneInterfaceName;                        ///< Backbone network interface name.
-    const char *mInterfaceName;                                ///< Thread network interface name.
-    const char *mRadioUrls[OT_PLATFORM_CONFIG_MAX_RADIO_URLS]; ///< Radio URLs.
-    uint8_t     mRadioUrlNum;                                  ///< Number of Radio URLs.
-    int         mRealTimeSignal;                               ///< The real-time signal for microsecond timer.
-    uint32_t    mSpeedUpFactor;                                ///< Speed up factor.
-    bool        mPersistentInterface;                          ///< Whether persistent the interface
-    bool        mDryRun;                                       ///< If 'DryRun' is set, the posix daemon will exit
-                                                               ///< directly after initialization.
-    CoprocessorType mCoprocessorType;                          ///< The co-processor type. This field is used to pass
-                                                               ///< the type to the app layer.
+    const char               *mBackboneInterfaceName; ///< Backbone network interface name.
+    const char               *mInterfaceName;         ///< Thread network interface name.
+    otPlatformCoprocessorUrls mCoprocessorUrls;       ///< Coprocessor URLs.
+    int                       mRealTimeSignal;        ///< The real-time signal for microsecond timer.
+    uint32_t                  mSpeedUpFactor;         ///< Speed up factor.
+    bool                      mPersistentInterface;   ///< Whether persistent the interface
+    bool                      mDryRun;                ///< If 'DryRun' is set, the posix daemon will exit
+                                                      ///< directly after initialization.
+    CoprocessorType mCoprocessorType;                 ///< The co-processor type. This field is used to pass
+                                                      ///< the type to the app layer.
 } otPlatformConfig;
 
+/**
+ * Initializes the co-processor and the spinel driver.
+ *
+ * @note This API will initialize the co-processor by resetting it and return the co-processor type.
+ *       If this API is called, the upcoming call of `otSysInit` won't initialize the co-processor
+ *       and the spinel driver again, unless `otSysDeinit` is called. This API is used to get the
+ *       co-processor type without calling `otSysInit`.
+ *
+ * @param[in]  aUrls  The URLs to initialize the co-processor.
+ *
+ * @returns The co-processor type.
+ *
+ */
+CoprocessorType otSysInitCoprocessor(otPlatformCoprocessorUrls *aUrls);
+
 /**
  * Performs all platform-specific initialization of OpenThread's drivers and initializes the OpenThread
  * instance.

src/posix/platform/system.cpp

@@ -82,20 +82,20 @@ static void processStateChange(otChangedFlags aFlags, void *aContext)
 }
 #endif
 
-static const char *get802154RadioUrl(otPlatformConfig *aPlatformConfig)
+static const char *get802154RadioUrl(const otPlatformCoprocessorUrls &aUrls)
 {
     const char *radioUrl = nullptr;
 
-    for (uint8_t i = 0; i < aPlatformConfig->mRadioUrlNum; i++)
+    for (uint8_t i = 0; i < aUrls.mNum; i++)
     {
-        ot::Posix::RadioUrl url(aPlatformConfig->mRadioUrls[i]);
+        ot::Posix::RadioUrl url(aUrls.mUrls[i]);
 
         if (strcmp(url.GetProtocol(), "trel") == 0)
         {
             continue;
         }
 
-        radioUrl = aPlatformConfig->mRadioUrls[i];
+        radioUrl = aUrls.mUrls[i];
         break;
     }
 
@@ -108,13 +108,13 @@ static const char *getTrelRadioUrl(otPlatformConfig *aPlatformConfig)
 {
     const char *radioUrl = nullptr;
 
-    for (uint8_t i = 0; i < aPlatformConfig->mRadioUrlNum; i++)
+    for (uint8_t i = 0; i < aPlatformConfig->mCoprocessorUrls.mNum; i++)
     {
-        ot::Posix::RadioUrl url(aPlatformConfig->mRadioUrls[i]);
+        ot::Posix::RadioUrl url(aPlatformConfig->mCoprocessorUrls.mUrls[i]);
 
         if (strcmp(url.GetProtocol(), "trel") == 0)
         {
-            radioUrl = aPlatformConfig->mRadioUrls[i];
+            radioUrl = aPlatformConfig->mCoprocessorUrls.mUrls[i];
             break;
         }
     }
@@ -132,7 +132,7 @@ void otSysSetInfraNetif(const char *aInfraNetifName, int aIcmp6Socket)
 
 void platformInitRcpMode(otPlatformConfig *aPlatformConfig)
 {
-    platformRadioInit(get802154RadioUrl(aPlatformConfig));
+    platformRadioInit(get802154RadioUrl(aPlatformConfig->mCoprocessorUrls));
 
     // For Dry-Run option, only init the co-processor.
     VerifyOrExit(!aPlatformConfig->mDryRun);
@@ -181,7 +181,10 @@ void platformInit(otPlatformConfig *aPlatformConfig)
 
     platformAlarmInit(aPlatformConfig->mSpeedUpFactor, aPlatformConfig->mRealTimeSignal);
 
-    sCoprocessorType = platformSpinelManagerInit(get802154RadioUrl(aPlatformConfig));
+    if (sCoprocessorType == OT_COPROCESSOR_UNKNOWN)
+    {
+        sCoprocessorType = platformSpinelManagerInit(get802154RadioUrl(aPlatformConfig->mCoprocessorUrls));
+    }
 
     switch (sCoprocessorType)
     {
@@ -249,6 +252,12 @@ exit:
     return;
 }
 
+CoprocessorType otSysInitCoprocessor(otPlatformCoprocessorUrls *aUrls)
+{
+    sCoprocessorType = platformSpinelManagerInit(get802154RadioUrl(*aUrls));
+    return sCoprocessorType;
+}
+
 otInstance *otSysInit(otPlatformConfig *aPlatformConfig)
 {
     OT_ASSERT(gInstance == nullptr);