armv7m: add MPU configuration support

Cortex-M archs support option memory protection unit (MPU). MPU is used
to set the memory types, attributes, access permissions for different regions,
cache policies of the device.

e.g. using MPU it is possible to configure memory region as device memory
or strongly ordered, memory attributes like execute never, cache policies
like write-back or write-through.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>

1 files changed, 67 insertions, 0 deletions

diff --git a/arch/arm/include/asm/armv7m_mpu.h b/arch/arm/include/asm/armv7m_mpu.h
new file mode 100644
index 0000000000..d7e99b4d8d
--- /dev/null
+++ b/arch/arm/include/asm/armv7m_mpu.h
@@ -0,0 +1,67 @@
+/*
+ * (C) Copyright 2017
+ * Vikas Manocha, ST Micoelectronics, vikas.manocha@st.com.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+enum region_number {
+	REGION_0 = 0,
+	REGION_1,
+	REGION_2,
+	REGION_3,
+	REGION_4,
+	REGION_5,
+	REGION_6,
+	REGION_7,
+};
+
+enum ap {
+	NO_ACCESS = 0,
+	PRIV_RW_USR_NO,
+	PRIV_RW_USR_RO,
+	PRIV_RW_USR_RW,
+	UNPREDICTABLE,
+	PRIV_RO_USR_NO,
+	PRIV_RO_USR_RO,
+};
+
+enum mr_attr {
+	STRONG_ORDER = 0,
+	SHARED_WRITE_BUFFERED,
+	O_I_WT_NO_WR_ALLOC,
+	O_I_WB_NO_WR_ALLOC,
+	O_I_NON_CACHEABLE,
+	O_I_WB_RD_WR_ALLOC,
+	DEVICE_NON_SHARED,
+};
+enum size {
+	REGION_8MB = 22,
+	REGION_16MB,
+	REGION_32MB,
+	REGION_64MB,
+	REGION_128MB,
+	REGION_256MB,
+	REGION_512MB,
+	REGION_1GB,
+	REGION_2GB,
+	REGION_4GB,
+};
+
+enum xn {
+	XN_DIS = 0,
+	XN_EN,
+};
+
+struct mpu_region_config {
+	uint32_t start_addr;
+	enum region_number region_no;
+	enum xn xn;
+	enum ap ap;
+	enum mr_attr mr_attr;
+	enum size reg_size;
+};
+
+void disable_mpu(void);
+void enable_mpu(void);
+void mpu_config(struct mpu_region_config *reg_config);