From 5aa2fb1443c346b2995f317cf2e70f3a8fd90da8 Mon Sep 17 00:00:00 2001
From: h2zero <powell.rg@gmail.com>
Date: Wed, 13 Nov 2024 13:41:02 -0700
Subject: [PATCH] Refactor NimBLEUtils::taskWait to check notification value
 before blocking.

Instead of incrementing the notificatin value via `xTaskNotifyGive` this will now set a specific bit in the task notification value
which will be tested before blocking a task. This will prevent a task from blocking indefinitely if the event that calls `taskRelease`
occurs before entering the blocked state.

* Adds a config setting for the bit to set in the task notification value.
---
 Kconfig             |  7 +++++++
 src/NimBLEUtils.cpp | 20 +++++++++++++-------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/Kconfig b/Kconfig
index db71798..2a603c6 100644
--- a/Kconfig
+++ b/Kconfig
@@ -76,6 +76,13 @@ config NIMBLE_CPP_DEBUG_ASSERT_ENABLED
         Enabling this option will add debug asserts to the NimBLE CPP library.
         This will use approximately 1kB of flash memory.
 
+config NIMBLE_CPP_FREERTOS_TASK_BLOCK_BIT
+    int "FreeRTOS task block bit"
+    default 31
+    help
+        Configure the bit to set in the task notification value when a task is blocked waiting for an event.
+        This should be set to a bit that is not used by other notifications in the system.
+        
 #
 # BT config
 #
diff --git a/src/NimBLEUtils.cpp b/src/NimBLEUtils.cpp
index d69cdee..f722be7 100644
--- a/src/NimBLEUtils.cpp
+++ b/src/NimBLEUtils.cpp
@@ -27,6 +27,10 @@
 # include <stdlib.h>
 # include <climits>
 
+# if defined INC_FREERTOS_H
+constexpr uint32_t TASK_BLOCK_BIT = (1 << CONFIG_NIMBLE_CPP_FREERTOS_TASK_BLOCK_BIT);
+# endif
+
 static const char* LOG_TAG = "NimBLEUtils";
 
 /**
@@ -44,12 +48,14 @@ bool NimBLEUtils::taskWait(const NimBLETaskData& taskData, uint32_t timeout) {
     }
 
 # if defined INC_FREERTOS_H
+    uint32_t notificationValue;
+    xTaskNotifyWait(0, TASK_BLOCK_BIT, &notificationValue, 0);
+    if (notificationValue & TASK_BLOCK_BIT) {
+        return true;
+    }
+
     taskData.m_pHandle = xTaskGetCurrentTaskHandle();
-#  ifdef ulTaskNotifyValueClear
-    // Clear the task notification value to ensure we block
-    ulTaskNotifyValueClear(static_cast<TaskHandle_t>(taskData.m_pHandle), ULONG_MAX);
-#  endif
-    return ulTaskNotifyTake(pdTRUE, ticks) == pdTRUE;
+    return xTaskNotifyWait(0, TASK_BLOCK_BIT, nullptr, ticks) == pdTRUE;
 
 # else
     ble_npl_sem     sem;
@@ -73,10 +79,10 @@ bool NimBLEUtils::taskWait(const NimBLETaskData& taskData, uint32_t timeout) {
  * @param [in] flags A return value to set in the task data structure.
  */
 void NimBLEUtils::taskRelease(const NimBLETaskData& taskData, int flags) {
+    taskData.m_flags = flags;
     if (taskData.m_pHandle != nullptr) {
-        taskData.m_flags = flags;
 # if defined INC_FREERTOS_H
-        xTaskNotifyGive(static_cast<TaskHandle_t>(taskData.m_pHandle));
+        xTaskNotify(static_cast<TaskHandle_t>(taskData.m_pHandle), TASK_BLOCK_BIT, eSetBits);
 # else
         ble_npl_sem_release(static_cast<ble_npl_sem*>(taskData.m_pHandle));
 # endif