From 37fef5ed547421e627b69193798d2556b3cebe19 Mon Sep 17 00:00:00 2001
From: Ashish <104561745+aashu216@users.noreply.github.com>
Date: Wed, 28 Feb 2024 05:31:29 +0530
Subject: [PATCH] [spinel] drop received frames between RCP disable and reset
 (#9793)

Signed-off-by: Ashishkumar Vara <ashish.vara@nxp.com>
---
 src/lib/spinel/multi_frame_buffer.hpp | 2 +-
 src/lib/spinel/radio_spinel.cpp       | 3 +++
 src/lib/spinel/spinel_encoder.cpp     | 2 ++
 src/lib/spinel/spinel_encoder.hpp     | 6 ++++++
 src/ncp/ncp_base.cpp                  | 2 ++
 5 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/lib/spinel/multi_frame_buffer.hpp b/src/lib/spinel/multi_frame_buffer.hpp
index ab1ef835b..61945a5ca 100644
--- a/src/lib/spinel/multi_frame_buffer.hpp
+++ b/src/lib/spinel/multi_frame_buffer.hpp
@@ -371,7 +371,7 @@ public:
 
         aFrame = (aFrame == nullptr) ? mBuffer : aFrame + aLength;
 
-        if (aFrame != mWriteFrameStart)
+        if (HasSavedFrame() && (aFrame != mWriteFrameStart))
         {
             uint16_t totalLength = LittleEndian::ReadUint16(aFrame + kHeaderTotalLengthOffset);
             uint16_t skipLength  = LittleEndian::ReadUint16(aFrame + kHeaderSkipLengthOffset);
diff --git a/src/lib/spinel/radio_spinel.cpp b/src/lib/spinel/radio_spinel.cpp
index b41fde342..a0ab17238 100644
--- a/src/lib/spinel/radio_spinel.cpp
+++ b/src/lib/spinel/radio_spinel.cpp
@@ -670,6 +670,9 @@ void RadioSpinel::HandleValueIs(spinel_prop_key_t aKey, const uint8_t *aBuffer,
                 ExitNow();
             }
 
+            // this clear is necessary in case the RCP has sent messages between disable and reset
+            mRxFrameBuffer.Clear();
+
             LogInfo("RCP reset: %s", spinel_status_to_cstr(status));
             sIsReady = true;
         }
diff --git a/src/lib/spinel/spinel_encoder.cpp b/src/lib/spinel/spinel_encoder.cpp
index 91a9ec36c..6cd390486 100644
--- a/src/lib/spinel/spinel_encoder.cpp
+++ b/src/lib/spinel/spinel_encoder.cpp
@@ -291,5 +291,7 @@ exit:
     return error;
 }
 
+void Encoder::ClearNcpBuffer(void) { mNcpBuffer.Clear(); }
+
 } // namespace Spinel
 } // namespace ot
diff --git a/src/lib/spinel/spinel_encoder.hpp b/src/lib/spinel/spinel_encoder.hpp
index 6b9ea983d..c678519b4 100644
--- a/src/lib/spinel/spinel_encoder.hpp
+++ b/src/lib/spinel/spinel_encoder.hpp
@@ -676,6 +676,12 @@ public:
      */
     otError ResetToSaved(void);
 
+    /**
+     * Clear NCP buffer on reset command.
+     *
+     */
+    void ClearNcpBuffer(void);
+
 private:
     enum
     {
diff --git a/src/ncp/ncp_base.cpp b/src/ncp/ncp_base.cpp
index e0b4c1881..a1ad3adb3 100644
--- a/src/ncp/ncp_base.cpp
+++ b/src/ncp/ncp_base.cpp
@@ -1285,6 +1285,8 @@ otError NcpBase::CommandHandler_RESET(uint8_t aHeader)
 
         ResetCounters();
 
+        mEncoder.ClearNcpBuffer();
+
         SuccessOrAssert(error = WriteLastStatusFrame(SPINEL_HEADER_FLAG | SPINEL_HEADER_TX_NOTIFICATION_IID,
                                                      SPINEL_STATUS_RESET_POWER_ON));
     }