Add IAR support for the target AN385 of MPS2.

Add file MPS2.icf and startup_MPS2.S to suppout IAR of the target
AN385(ARM_MPS2_M3). Add "IAR" to supported_toolchain list.

Change-Id: I038b05b8b21bd146a1568de897ed030ccd52ab79
Signed-off-by: Shawn Shan <[email protected]>

Author: ChangwuShan

targets/TARGET_ARM_SSG/TARGET_MPS2/TARGET_MPS2_M3/device/TOOLCHAIN_IAR/MPS2.icf

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2009-2019 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License) you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * This file is derivative of mbed-os V5.10.4 CM3DS MPS2.icf for IAR
+ */
+
+/* Code memory zones */
+define symbol ZBT_SSRAM1_START  = 0x00000000;
+define symbol ZBT_SSRAM1_SIZE   = 0x00400000; /* 4 MiB */
+
+/* Data memory zones */
+define symbol ZBT_SSRAM23_START = 0x20000000;
+define symbol ZBT_SSRAM23_SIZE  = 0x00400000; /* 4 MiB */
+
+/* NVIC vector numbers and size. */
+define symbol NVIC_NUM_VECTORS        = 16 + 48;
+define symbol NVIC_VECTORS_SIZE       = NVIC_NUM_VECTORS * 4;
+
+/* Specials */
+define symbol __ICFEDIT_intvec_start__ = ZBT_SSRAM1_START;
+
+/* Memory Regions */
+define symbol __ICFEDIT_region_ROM_start__    = ZBT_SSRAM1_START;
+define symbol __ICFEDIT_region_ROM_end__      = ZBT_SSRAM1_START + ZBT_SSRAM1_SIZE - 1;
+/*
+ * At execution, RAM is set to be in ZBT SSRAM2 and 3, just after the vector
+ * table previously moved from Flash.
+ */
+define symbol __ICFEDIT_region_RAM_start__    = ZBT_SSRAM23_START + NVIC_VECTORS_SIZE;
+define symbol __ICFEDIT_region_RAM_end__      = ZBT_SSRAM23_START + ZBT_SSRAM23_SIZE;
+
+/* Sizes */
+/* Heap and Stack size */
+define symbol __ICFEDIT_size_heap__   = 0x1000;
+define symbol __ICFEDIT_size_cstack__ = 0x400;
+
+define memory mem with size = 4G;
+define region ROM_region      = mem:[from __ICFEDIT_region_ROM_start__   to __ICFEDIT_region_ROM_end__];
+define region RAM_region      = mem:[from __ICFEDIT_region_RAM_start__   to __ICFEDIT_region_RAM_end__];
+
+initialize by copy { readwrite };
+do not initialize  { section .noinit };
+
+define block CSTACK    with alignment = 8, size = __ICFEDIT_size_cstack__   { };
+define block HEAP      with alignment = 8, size = __ICFEDIT_size_heap__     { };
+
+place at address mem:__ICFEDIT_intvec_start__ { readonly section .intvec };
+place in ROM_region   { readonly };
+place in RAM_region   { readwrite,
+                        block CSTACK, block HEAP };