Add MPU driver for stm32f769

2 files changed, 72 insertions, 0 deletions

diff --git a/os/drivers/memory/stm32f7_mpu.c b/os/drivers/memory/stm32f7_mpu.c
new file mode 100644
index 00000000..dbca7027
--- /dev/null
+++ b/os/drivers/memory/stm32f7_mpu.c
@@ -0,0 +1,63 @@
+#include <stdint.h>
+#include "stm32f7_mpu.h"
+#include <drivers/include/device.h>
+#include <arch/aarch32/stm32f7/stm32f769xx.h>
+#include <arch/aarch32/core_cm7.h>
+
+static void __mpu_disable(void)
+{
+  /* Make sure outstanding transfers are done */
+  __DMB();
+
+  /* Disable fault exceptions */
+  SCB->SHCSR &= ~SCB_SHCSR_MEMFAULTENA_Msk;
+  
+  /* Disable the MPU and clear the control register*/
+  MPU->CTRL = 0;
+}
+
+static void __mpu_enable(uint32_t ctrl)
+{
+  /* Enable the MPU */
+  MPU->CTRL = ctrl | MPU_CTRL_ENABLE_Msk;
+  
+  /* Enable fault exceptions */
+  SCB->SHCSR |= SCB_SHCSR_MEMFAULTENA_Msk;
+  
+  /* Ensure MPU setting take effects */
+  __DSB();
+  __ISB();
+}
+
+int stm32f7_mpu_init(struct device *dev) {
+  dev->devptr = (void *)MPU;
+
+  __mpu_disable();
+  MPU->RNR = MPU_REGION_NUMBER0;
+
+  /* Disable the Region */
+  CLEAR_BIT(MPU->RASR, MPU_RASR_ENABLE_Msk);
+
+  /* Apply configuration */
+  MPU->RBAR = 0; // Base addr
+
+  uint32_t rasr = MPU_INSTRUCTION_ACCESS_DISABLE << MPU_RASR_XN_Pos;
+  rasr |= MPU_REGION_SIZE_4GB << MPU_RASR_SIZE_Pos;
+  rasr |= MPU_REGION_NO_ACCESS << MPU_RASR_AP_Pos;
+  rasr |= MPU_ACCESS_NOT_BUFFERABLE << MPU_RASR_B_Pos;
+  rasr |= MPU_ACCESS_NOT_CACHEABLE << MPU_RASR_C_Pos;
+  rasr |= MPU_ACCESS_SHAREABLE << MPU_RASR_S_Pos;
+  rasr |= MPU_TEX_LEVEL0 << MPU_RASR_TEX_Pos;
+  rasr |= 0x87 << MPU_RASR_SRD_Pos; // Sub region disable
+  rasr |= MPU_REGION_ENABLE << MPU_RASR_ENABLE_Pos;
+  
+  MPU->RASR = rasr;
+
+  __mpu_enable(MPU_PRIVILEGED_DEFAULT);
+
+  return 0;
+}
+
+int stm32f7_mpu_deinit(struct device *dev) {
+  return 0;
+}
diff --git a/os/drivers/memory/stm32f7_mpu.h b/os/drivers/memory/stm32f7_mpu.h
new file mode 100644
index 00000000..4e81453c
--- /dev/null
+++ b/os/drivers/memory/stm32f7_mpu.h
@@ -0,0 +1,9 @@
+#ifndef __STM32F7_MPU_H__
+#define __STM32F7_MPU_H__
+
+#include <drivers/include/device.h>
+
+int stm32f7_mpu_init(struct device *dev);
+int stm32f7_mpu_deinit(struct device *dev);
+
+#endif/*__STM32F7_MPU_H__*/