From f856b89723f4be62cb53a0d9f70647aeee7279b3 Mon Sep 17 00:00:00 2001
From: Daniel Agar <daniel@agar.ca>
Date: Tue, 31 Aug 2021 18:01:06 -0400
Subject: [PATCH] boards: Holybro H7 boards clear MPU early in board init

 - needed if the bootloader configures the memory protection unit (MPU)
---
 boards/holybro/durandal-v1/src/init.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/boards/holybro/durandal-v1/src/init.c b/boards/holybro/durandal-v1/src/init.c
index 05746c4959..3f1eccc180 100644
--- a/boards/holybro/durandal-v1/src/init.c
+++ b/boards/holybro/durandal-v1/src/init.c
@@ -75,6 +75,8 @@
 #include <px4_platform/board_determine_hw_info.h>
 #include <px4_platform/board_dma_alloc.h>
 
+#include <mpu.h>
+
 /****************************************************************************
  * Pre-Processor Definitions
  ****************************************************************************/
@@ -160,6 +162,16 @@ __EXPORT void board_on_reset(int status)
 __EXPORT void
 stm32_boardinitialize(void)
 {
+	// clear all existing MPU configuration from bootloader
+	for (int region = 0; region < CONFIG_ARM_MPU_NREGIONS; region++) {
+		putreg32(region, MPU_RNR);
+		putreg32(0, MPU_RBAR);
+		putreg32(0, MPU_RASR);
+
+		// save
+		putreg32(0, MPU_CTRL);
+	}
+
 	board_on_reset(-1); /* Reset PWM first thing */
 
 	/* configure LEDs */