From 2af6642f683206c3a94cc0e38eff3403cebd67f3 Mon Sep 17 00:00:00 2001
From: Russ Butler <russ.butler@arm.com>
Date: Mon, 10 Dec 2018 14:26:13 -0600
Subject: [PATCH] Add a platform config to disable the MPU

Add the platform config DISABLE_MPU to allow the MPU to be disabled
from an application.
---
 hal/mpu/mbed_mpu_v7m.c   | 2 +-
 hal/mpu/mbed_mpu_v8m.c   | 2 +-
 hal/mpu_api.h            | 2 +-
 platform/mbed_lib.json   | 4 ++++
 platform/mbed_mpu_mgmt.c | 2 +-
 platform/mbed_mpu_mgmt.h | 2 +-
 6 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/hal/mpu/mbed_mpu_v7m.c b/hal/mpu/mbed_mpu_v7m.c
index 5778e74739..96592ad625 100644
--- a/hal/mpu/mbed_mpu_v7m.c
+++ b/hal/mpu/mbed_mpu_v7m.c
@@ -20,7 +20,7 @@
 
 #if ((__ARM_ARCH_7M__ == 1U) || (__ARM_ARCH_7EM__ == 1U) || (__ARM_ARCH_6M__ == 1U)) && \
     defined (__MPU_PRESENT) && (__MPU_PRESENT == 1U) && \
-    !defined(MBED_MPU_CUSTOM)
+    !defined(MBED_MPU_CUSTOM) && !MBED_CONF_PLATFORM_DISABLE_MPU
 
 #if !DEVICE_MPU
 #error "Device has v7m MPU but it is not enabled. Add 'MPU' to device_has in targets.json"
diff --git a/hal/mpu/mbed_mpu_v8m.c b/hal/mpu/mbed_mpu_v8m.c
index 7304c149b9..de0c362ba1 100644
--- a/hal/mpu/mbed_mpu_v8m.c
+++ b/hal/mpu/mbed_mpu_v8m.c
@@ -20,7 +20,7 @@
 
 #if ((__ARM_ARCH_8M_BASE__ == 1U) || (__ARM_ARCH_8M_MAIN__ == 1U)) && \
     defined (__MPU_PRESENT) && (__MPU_PRESENT == 1U) && \
-    !defined(MBED_MPU_CUSTOM)
+    !defined(MBED_MPU_CUSTOM) && !MBED_CONF_PLATFORM_DISABLE_MPU
 
 #if !DEVICE_MPU
 #error "Device has v8m MPU but it is not enabled. Add 'MPU' to device_has in targets.json"
diff --git a/hal/mpu_api.h b/hal/mpu_api.h
index 5ce034779e..1979731b5c 100644
--- a/hal/mpu_api.h
+++ b/hal/mpu_api.h
@@ -26,7 +26,7 @@
 extern "C" {
 #endif
 
-#if DEVICE_MPU
+#if DEVICE_MPU && !MBED_CONF_PLATFORM_DISABLE_MPU
 
 /**
  * \defgroup hal_mpu MPU hal
diff --git a/platform/mbed_lib.json b/platform/mbed_lib.json
index 821df0b672..8dd22bddbd 100644
--- a/platform/mbed_lib.json
+++ b/platform/mbed_lib.json
@@ -128,6 +128,10 @@
         "fatal-error-auto-reboot-enabled": {
             "help": "Setting this to true enables auto-reboot on a fatal error.",
             "value": false
+        },
+        "disable-mpu": {
+            "help": "Disable the MPU to save rom.",
+            "value": false
         }
     },
     "target_overrides": {
diff --git a/platform/mbed_mpu_mgmt.c b/platform/mbed_mpu_mgmt.c
index 7a067a4281..2c5423a275 100644
--- a/platform/mbed_mpu_mgmt.c
+++ b/platform/mbed_mpu_mgmt.c
@@ -21,7 +21,7 @@
 #include "hal/mpu_api.h"
 #include <limits.h>
 
-#if DEVICE_MPU
+#if DEVICE_MPU && !MBED_CONF_PLATFORM_DISABLE_MPU
 
 static uint16_t mem_xn_lock;
 static uint16_t mem_wn_lock;
diff --git a/platform/mbed_mpu_mgmt.h b/platform/mbed_mpu_mgmt.h
index 8b1e422f58..cc79feee35 100644
--- a/platform/mbed_mpu_mgmt.h
+++ b/platform/mbed_mpu_mgmt.h
@@ -32,7 +32,7 @@
 extern "C" {
 #endif
 
-#if DEVICE_MPU
+#if DEVICE_MPU && !MBED_CONF_PLATFORM_DISABLE_MPU
 
 /** Lock ram execute never mode off
  *