Add module for controlling the MPU.

The MPU is a module in arm chips which allow for memory access
protection. They are more primitive than full MMUs, but can still
provide at least basic access control between different process
controls.

1 files changed, 40 insertions, 0 deletions

diff --git a/include/arch/arm/cortex-m4/mpu.h b/include/arch/arm/cortex-m4/mpu.h
new file mode 100644
index 0000000..fedaf79
--- /dev/null
+++ b/include/arch/arm/cortex-m4/mpu.h
@@ -0,0 +1,40 @@
+#ifndef ARCH_ARM_CORTEX_M4_MPU_H_
+#define ARCH_ARM_CORTEX_M4_MPU_H_
+
+#include "arch.h"
+
+typedef volatile struct {
+  volatile uint32_t type_r;
+#define mpu_en (1 << 0)
+  volatile uint32_t ctrl_r;
+  volatile uint32_t rn_r;
+
+  /**
+   * On the ARM Cortex-M4 processor, the
+   */
+  volatile union {
+#define mpu_size (0x1F << 1)
+#define mpu_srd (0xFF << 8)
+#define mpu_b (1 << 16)
+#define mpu_c (1 << 17)
+#define mpu_s (1 << 18)
+#define mpu_tex (7 << 19)
+#define mpu_ap (3 << 24)
+#define mpu_xn (1 << 28)
+
+#define mpu_valid (1 << 4)
+#define mpu_region (0xF << 0)
+    struct {
+      uint32_t rba_r;
+      uint32_t ras_r;
+    };
+    struct {
+      uint32_t rba_r;
+      uint32_t ras_r;
+    } aliased[4];
+  };
+} mpu_t;
+
+#define MPU (*((mpu_t*)(MPU_BASE)))
+
+#endif /* ARCH_ARM_CORTEX_M4_MPU_H_ */