From a7c43cd93fbe9cb0efd7e2fb89836c60fbe6ff7c Mon Sep 17 00:00:00 2001
From: Aurora <davidone92@katamail.com>
Date: Thu, 9 Jun 2016 16:52:12 +0200
Subject: [PATCH] Disable caches/mpu before changing MPU settings

---
 source/start.s | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/source/start.s b/source/start.s
index 52f88b9..4c91264 100644
--- a/source/start.s
+++ b/source/start.s
@@ -5,6 +5,13 @@ _start:
     @ Change the stack pointer
     mov sp, #0x27000000
 
+    @ Disable caches / MPU
+    mrc p15, 0, r0, c1, c0, 0  @ read control register
+    bic r0, #(1<<12)           @ - instruction cache disable
+    bic r0, #(1<<2)            @ - data cache disable
+    bic r0, #(1<<0)            @ - mpu disable
+    mcr p15, 0, r0, c1, c0, 0  @ write control register
+
     @ Give read/write access to all the memory regions
     ldr r0, =0x33333333
     mcr p15, 0, r0, c5, c0, 2 @ write data access
@@ -32,7 +39,7 @@ _start:
     mcr p15, 0, r8, c2, c0, 0	@ Data cacheable 0, 3, 5
     mcr p15, 0, r8, c2, c0, 1	@ Inst cacheable 0, 3, 5
 
-    @ Enable caches
+    @ Enable caches / MPU
     mrc p15, 0, r0, c1, c0, 0  @ read control register
     orr r0, r0, #(1<<12)       @ - instruction cache enable
     orr r0, r0, #(1<<2)        @ - data cache enable