[diag] Move otPlatDiagModeGet() check to ProcessCmd

All diagnostic commands (instead of `diag start`) should fail if
device is not in diagnostic mode. Previously it was verified by
each command's process method (with a missing check in
`ProcessEcho` and `ProcessGpio`). This commit moves the check
directly to `ProcessCmd` and cleans up redundant code.

Signed-off-by: Maciej Baczmanski <maciej.baczmanski@nordicsemi.no>

Author: maciejbaczmanski

src/core/diags/factory_diags.cpp

@@ -334,8 +334,6 @@ Error Diags::ProcessChannel(uint8_t aArgsLength, char *aArgs[])
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
-
     if (aArgsLength == 0)
     {
         Output("channel: %d\r\n", mChannel);
@@ -363,8 +361,6 @@ Error Diags::ProcessPower(uint8_t aArgsLength, char *aArgs[])
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
-
     if (aArgsLength == 0)
     {
         Output("tx power: %d dBm\r\n", mTxPower);
@@ -391,7 +387,6 @@ Error Diags::ProcessRepeat(uint8_t aArgsLength, char *aArgs[])
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
     VerifyOrExit(aArgsLength > 0, error = kErrorInvalidArgs);
 
     if (StringMatch(aArgs[0], "stop"))
@@ -446,7 +441,6 @@ Error Diags::ProcessSend(uint8_t aArgsLength, char *aArgs[])
     uint32_t txPackets;
     uint8_t  txLength;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
     VerifyOrExit(aArgsLength >= 1, error = kErrorInvalidArgs);
 
     SuccessOrExit(error = Utils::CmdLineParser::ParseAsUint32(aArgs[0], txPackets));
@@ -512,8 +506,6 @@ Error Diags::ProcessStats(uint8_t aArgsLength, char *aArgs[])
 {
     Error error = kErrorNone;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
-
     if ((aArgsLength == 1) && StringMatch(aArgs[0], "clear"))
     {
         mStats.Clear();
@@ -542,8 +534,6 @@ Error Diags::ProcessStop(uint8_t aArgsLength, char *aArgs[])
 
     Error error = kErrorNone;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
-
     otPlatAlarmMilliStop(&GetInstance());
     otPlatDiagModeSet(false);
     Get<Radio>().SetPromiscuous(false);
@@ -635,7 +625,6 @@ Error Diags::ProcessRadio(uint8_t aArgsLength, char *aArgs[])
 {
     Error error = kErrorInvalidArgs;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
     VerifyOrExit(aArgsLength > 0, error = kErrorInvalidArgs);
 
     if (StringMatch(aArgs[0], "sleep"))
@@ -840,7 +829,6 @@ Error Diags::ProcessContinuousWave(uint8_t aArgsLength, char *aArgs[])
 {
     Error error = kErrorInvalidArgs;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
     VerifyOrExit(aArgsLength > 0, error = kErrorInvalidArgs);
 
     if (StringMatch(aArgs[0], "start"))
@@ -861,7 +849,6 @@ Error Diags::ProcessStream(uint8_t aArgsLength, char *aArgs[])
 {
     Error error = kErrorInvalidArgs;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
     VerifyOrExit(aArgsLength > 0, error = kErrorInvalidArgs);
 
     if (StringMatch(aArgs[0], "start"))
@@ -892,8 +879,6 @@ Error Diags::ProcessPowerSettings(uint8_t aArgsLength, char *aArgs[])
     uint8_t       channel;
     PowerSettings powerSettings;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
-
     if (aArgsLength == 0)
     {
         bool          isPrePowerSettingsValid = false;
@@ -951,8 +936,6 @@ Error Diags::ProcessRawPowerSetting(uint8_t aArgsLength, char *aArgs[])
     Error           error = kErrorInvalidArgs;
     RawPowerSetting setting;
 
-    VerifyOrExit(otPlatDiagModeGet(), error = kErrorInvalidState);
-
     if (aArgsLength == 0)
     {
         SuccessOrExit(error = GetRawPowerSetting(setting));
@@ -1112,6 +1095,8 @@ Error Diags::ProcessCmd(uint8_t aArgsLength, char *aArgs[])
         ExitNow();
     }
 
+    VerifyOrExit(otPlatDiagModeGet() || StringMatch(aArgs[0], "start"), error = kErrorInvalidState);
+
     for (const Command &command : sCommands)
     {
         if (StringMatch(aArgs[0], command.mName))