nxp: added csu driver

NXP Central Security Unit(CSU) for NXP SoC.
CSU is used for:
- Access permissions for peripheral that donot have their own
  access control.
- Locking of individual CSU settings until the next POR
- General purpose security related control bits

Refer NXP SoC manuals fro more details.
Signed-off-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Change-Id: I07a4729c79c5e2597f8b2a782e87e09f7f30c2ca

drivers/nxp/csu/csu.c

+/*
+ * Copyright 2020 NXP
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include <endian.h>
+
+#include <common/debug.h>
+#include <csu.h>
+#include <lib/mmio.h>
+
+void enable_layerscape_ns_access(struct csu_ns_dev_st *csu_ns_dev,
+				 uint32_t num, uintptr_t nxp_csu_addr)
+{
+	uint32_t *base = (uint32_t *)nxp_csu_addr;
+	uint32_t *reg;
+	uint32_t val;
+	int i;
+
+	for (i = 0; i < num; i++) {
+		reg = base + csu_ns_dev[i].ind / 2U;
+		val = be32toh(mmio_read_32((uintptr_t)reg));
+		if (csu_ns_dev[i].ind % 2U == 0U) {
+			val &= 0x0000ffffU;
+			val |= csu_ns_dev[i].val << 16U;
+		} else {
+			val &= 0xffff0000U;
+			val |= csu_ns_dev[i].val;
+		}
+		mmio_write_32((uintptr_t)reg, htobe32(val));
+	}
+}

drivers/nxp/csu/csu.h

+/*
+ * Copyright 2020 NXP
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#ifndef CSU_H
+#define CSU_H
+
+#define CSU_SEC_ACCESS_REG_OFFSET	(0x0021CU)
+
+/* Macros defining access permissions to configure
+ * the regions controlled by Central Security Unit.
+ */
+enum csu_cslx_access {
+	CSU_NS_SUP_R = (0x8U),
+	CSU_NS_SUP_W = (0x80U),
+	CSU_NS_SUP_RW = (0x88U),
+	CSU_NS_USER_R = (0x4U),
+	CSU_NS_USER_W = (0x40U),
+	CSU_NS_USER_RW = (0x44U),
+	CSU_S_SUP_R = (0x2U),
+	CSU_S_SUP_W = (0x20U),
+	CSU_S_SUP_RW = (0x22U),
+	CSU_S_USER_R = (0x1U),
+	CSU_S_USER_W = (0x10U),
+	CSU_S_USER_RW = (0x11U),
+	CSU_ALL_RW = (0xffU),
+};
+
+struct csu_ns_dev_st {
+	uintptr_t ind;
+	uint32_t val;
+};
+
+void enable_layerscape_ns_access(struct csu_ns_dev_st *csu_ns_dev,
+				 uint32_t num, uintptr_t nxp_csu_addr);
+
+#endif

drivers/nxp/csu/csu.mk

+#
+# Copyright 2020 NXP
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-----------------------------------------------------------------------------
+ifeq (${CSU_ADDED},)
+
+CSU_ADDED		:= 1
+
+CSU_DRIVERS_PATH	:=  ${PLAT_DRIVERS_PATH}/csu
+
+PLAT_INCLUDES		+= -I$(CSU_DRIVERS_PATH)
+
+CSU_SOURCES		+= $(CSU_DRIVERS_PATH)/csu.c
+
+ifeq (${BL_COMM_CSU_NEEDED},yes)
+BL_COMMON_SOURCES	+= ${CSU_SOURCES}
+else
+ifeq (${BL2_CSU_NEEDED},yes)
+BL2_SOURCES		+= ${CSU_SOURCES}
+endif
+ifeq (${BL31_CSU_NEEDED},yes)
+BL31_SOURCES		+= ${CSU_SOURCES}
+endif
+endif
+
+endif