[nrf toup] platform: nordic_nrf: Add option to initialize hardware to…

… reset on boot

Add an option to the nordic platforms to initialize the hardware state
to the its reset values when the TF-M firmware is booting.
The option is useful when the TF-M firmware image is chain-loaded, for
example, a bootloader, and we need to guarantee that the internal
states of the architecture core blocks are restored to the reset values.

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>
(cherry picked from commit 9f3911b)
Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>

platform/ext/target/nordic_nrf/common/core/CMakeLists.txt

@@ -77,6 +77,18 @@ target_sources(platform_s
         plat_test.c
 )
 
+if (NRF_HW_INIT_RESET_ON_BOOT)
+    target_sources(platform_s
+        PRIVATE
+            hw_init.c
+    )
+
+    target_compile_definitions(platform_s
+        PUBLIC
+            NRF_HW_INIT_RESET_ON_BOOT
+    )
+endif()
+
 if(TFM_PARTITION_PLATFORM)
     target_sources(platform_s
         PRIVATE

platform/ext/target/nordic_nrf/common/core/config.cmake

@@ -20,3 +20,5 @@ set(NULL_POINTER_EXCEPTION_DETECTION    FALSE       CACHE BOOL
 
 set(PLATFORM_SLIH_IRQ_TEST_SUPPORT      ON          CACHE BOOL    "Platform supports SLIH IRQ tests")
 set(PLATFORM_FLIH_IRQ_TEST_SUPPORT      ON          CACHE BOOL    "Platform supports FLIH IRQ tests")
+
+set(NRF_HW_INIT_RESET_ON_BOOT CACHE BOOL OFF "Initialize internal architecture state at boot")

platform/ext/target/nordic_nrf/common/core/hw_init.c

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+#include <stdint.h>
+#include <nrf.h>
+#include "array.h"
+
+/* This routine clears all ARM MPU region configuration. */
+static void hw_init_mpu(void)
+{
+	const int num_regions =
+		((MPU->TYPE & MPU_TYPE_DREGION_Msk) >> MPU_TYPE_DREGION_Pos);
+
+	for (int i = 0; i < num_regions; i++) {
+		ARM_MPU_ClrRegion(i);
+	}
+}
+
+/* This routine resets Cortex-M system control block components and core
+ * registers.
+ */
+void hw_init_reset_on_boot(void)
+{
+	/* Disable interrupts */
+	__disable_irq();
+
+	/* Reset exception and interrupt mask state (PRIMASK handled by
+	 * __enable_irq below)
+	 */
+	__set_FAULTMASK(0);
+	__set_BASEPRI(0);
+
+	/* Clear MPU region configuration */
+	hw_init_mpu();
+
+	/* Disable NVIC interrupts */
+	for (int i = 0; i < ARRAY_SIZE(NVIC->ICER); i++) {
+		NVIC->ICER[i] = 0xFFFFFFFF;
+	}
+	/* Clear pending NVIC interrupts */
+	for (int i = 0; i < ARRAY_SIZE(NVIC->ICPR); i++) {
+		NVIC->ICPR[i] = 0xFFFFFFFF;
+	}
+
+	/* Restore Interrupts */
+	__enable_irq();
+
+	__DSB();
+	__ISB();
+}

platform/ext/target/nordic_nrf/common/core/hw_init.h

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2022 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+#ifndef HW_INIT_H__
+#define HW_INIT_H__
+
+#define _SCS_BASE_ADDR 0xE000E000
+#define _SCS_MPU_CTRL (_SCS_BASE_ADDR + 0xd94)
+
+#endif /* HW_INIT_H__*/

platform/ext/target/nordic_nrf/common/nrf5340/gcc/startup_nrf5340_s.S

@@ -22,6 +22,7 @@
  */
 
 #include "tfm_plat_config.h"
+#include "hw_init.h"
 
     .syntax unified
     .arch   armv8-m.main
@@ -128,6 +129,30 @@ __Vectors:
     .globl  Reset_Handler
     .type   Reset_Handler, %function
 Reset_Handler:
+
+/* If the ARM core status registers and system blocks are not in their initial
+ * reset values then reset these first before booting.
+ */
+#ifdef NRF_HW_INIT_RESET_ON_BOOT
+    movs r0, #0
+
+    /* Reset CONTROL register */
+    msr CONTROL, r0
+    isb
+
+    /* Clear SPLIM registers */
+    msr MSPLIM, r0
+    msr PSPLIM, r0
+
+    /* Disable MPU */
+    ldr r1, =_SCS_MPU_CTRL
+    str r0, [r1]
+    dsb
+
+    /* Initialize core architecture registers and system blocks */
+    bl hw_init_reset_on_boot
+#endif /* NRF_HW_INIT_RESET_ON_BOOT */
+
 /*  Firstly it copies data from read only memory to RAM. There are two schemes
  *  to copy. One can copy more than one sections. Another can only copy
  *  one section.  The former scheme needs more instructions and read-only

platform/ext/target/nordic_nrf/common/nrf9160/gcc/startup_nrf9160_s.S

@@ -22,6 +22,7 @@
  */
 
 #include "tfm_plat_config.h"
+#include "hw_init.h"
 
     .syntax unified
     .arch   armv8-m.main
@@ -124,6 +125,30 @@ __Vectors:
     .globl  Reset_Handler
     .type   Reset_Handler, %function
 Reset_Handler:
+
+/* If the ARM core status registers and system blocks are not in their initial
+ * reset values then reset these first before booting.
+ */
+#ifdef NRF_HW_INIT_RESET_ON_BOOT
+    movs r0, #0
+
+    /* Reset CONTROL register */
+    msr CONTROL, r0
+    isb
+
+    /* Clear SPLIM registers */
+    msr MSPLIM, r0
+    msr PSPLIM, r0
+
+    /* Disable MPU */
+    ldr r1, =_SCS_MPU_CTRL
+    str r0, [r1]
+    dsb
+
+    /* Initialize core architecture registers and system blocks */
+    bl hw_init_reset_on_boot
+#endif /* NRF_HW_INIT_RESET_ON_BOOT */
+
 /*  Firstly it copies data from read only memory to RAM. There are two schemes
  *  to copy. One can copy more than one sections. Another can only copy
  *  one section.  The former scheme needs more instructions and read-only