From a2c44269654665924033f1dbd2ad49aa7b0a41ba Mon Sep 17 00:00:00 2001
From: Seppo Takalo <seppo.takalo@arm.com>
Date: Thu, 3 Aug 2017 13:03:11 +0300
Subject: [PATCH] Allow using of malloc() for reserving the Nanostack's heap.

Some devices have RAM memory split into two sections.
This becames a problem for GCC based toolchains as they don't
support splitting .bss or .data sections into two memory parts.
When we run out of memory from .bss sections, allocating the stack
by malloc() allows it to be moved to .data section which might already
be in the second memory section. For example KW24D platform.
---
 .../FEATURE_NANOSTACK/mbed-mesh-api/README.md          |  1 +
 .../FEATURE_NANOSTACK/mbed-mesh-api/mbed_lib.json      |  1 +
 .../mbed-mesh-api/source/mesh_system.c                 | 10 ++++++++++
 3 files changed, 12 insertions(+)

diff --git a/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/README.md b/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/README.md
index 24aed7d7a9..eb50e73fb9 100644
--- a/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/README.md
+++ b/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/README.md
@@ -34,6 +34,7 @@ An example of the configuration file:
 | Parameter name  | Value         | Description |
 | --------------- | ------------- | ----------- |
 | heap-size       | number [0-0xfffe] | Nanostack's internal heap size |
+| use-malloc-for-heap | `false` or `true` | Use `malloc()` for reserving the internal heap. Default: `false` |
 
 ### Thread related configuration parameters
 
diff --git a/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/mbed_lib.json b/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/mbed_lib.json
index d668e2261d..c9401e662c 100644
--- a/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/mbed_lib.json
+++ b/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/mbed_lib.json
@@ -2,6 +2,7 @@
     "name": "mbed-mesh-api",
     "config": {
         "heap-size": 32500,
+        "use-malloc-for-heap": false,
         "6lowpan-nd-channel-mask": "(1<<12)",
         "6lowpan-nd-channel-page": 0,
         "6lowpan-nd-channel": 12,
diff --git a/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/source/mesh_system.c b/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/source/mesh_system.c
index a9505ad434..c87d7d3772 100644
--- a/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/source/mesh_system.c
+++ b/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api/source/mesh_system.c
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <stdlib.h>
 #include "eventOS_scheduler.h"
 #include "eventOS_event.h"
 #include "net_interface.h"
@@ -22,13 +23,18 @@
 #include "platform/arm_hal_timer.h"
 #include "ns_hal_init.h"
 #include "include/mesh_system.h"
+#include "mbed_assert.h"
 // For tracing we need to define flag, have include and define group
 #define HAVE_DEBUG 1
 #include "ns_trace.h"
 #define TRACE_GROUP  "m6-mesh-system"
 
 /* Heap for NanoStack */
+#if !MBED_CONF_MBED_MESH_API_USE_MALLOC_FOR_HEAP
 static uint8_t app_stack_heap[MBED_CONF_MBED_MESH_API_HEAP_SIZE + 1];
+#else
+static uint8_t *app_stack_heap;
+#endif
 static bool mesh_initialized = false;
 
 /*
@@ -55,6 +61,10 @@ static void mesh_system_heap_error_handler(heap_fail_t event)
 void mesh_system_init(void)
 {
     if (mesh_initialized == false) {
+#if MBED_CONF_MBED_MESH_API_USE_MALLOC_FOR_HEAP
+        app_stack_heap = malloc(MBED_CONF_MBED_MESH_API_HEAP_SIZE+1);
+        MBED_ASSERT(app_stack_heap);
+#endif
         ns_hal_init(app_stack_heap, MBED_CONF_MBED_MESH_API_HEAP_SIZE,
                     mesh_system_heap_error_handler, NULL);
         eventOS_scheduler_mutex_wait();