diff --git a/toolchain_ARMCLANG.cmake b/toolchain_ARMCLANG.cmake
new file mode 100644
index 0000000..032abb2
--- /dev/null
+++ b/toolchain_ARMCLANG.cmake
@@ -0,0 +1,253 @@
+#-------------------------------------------------------------------------------
+# Copyright (c) 2020, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+
+cmake_minimum_required(VERSION 3.15)
+
+SET(CMAKE_SYSTEM_NAME Generic)
+# This setting is overridden in ${TFM_PLATFORM}/preload.cmake. It can be set to
+# any value here.
+set(CMAKE_SYSTEM_PROCESSOR cortex-m23)
+
+set(CMAKE_C_COMPILER armclang)
+set(CMAKE_ASM_COMPILER armclang)
+
+set(LINKER_VENEER_OUTPUT_FLAG --import_cmse_lib_out=)
+set(COMPILER_CMSE_FLAG -mcmse)
+
+# This variable name is a bit of a misnomer. The file it is set to is included
+# at a particular step in the compiler initialisation. It is used here to
+# configure the extensions for object files. Despite the name, it also works
+# with the Ninja generator.
+set(CMAKE_USER_MAKE_RULES_OVERRIDE ${CMAKE_CURRENT_LIST_DIR}/cmake/set_extensions.cmake)
+
+# Cmake makes it _really_ hard to dynamically set the cmake_system_processor
+# (used for setting mcpu flags etc). Instead we load
+# platform/ext/target/${TFM_PLATFORM}/preload.cmake, which should run this macro
+# to reload the compiler autoconfig. Note that it can't be loaded in this file
+# as cmake does not allow the use of command-line defined variables in toolchain
+# files and the path is platform dependent.
+macro(_compiler_reload)
+    set(CMAKE_SYSTEM_PROCESSOR ${TFM_SYSTEM_PROCESSOR})
+    set(CMAKE_SYSTEM_ARCHITECTURE ${TFM_SYSTEM_ARCHITECTURE})
+
+    set_property(DIRECTORY PROPERTY COMPILE_OPTIONS "")
+    set_property(DIRECTORY PROPERTY LINK_OPTIONS "")
+    if(${CMAKE_C_COMPILER_VERSION} VERSION_GREATER_EQUAL "6.11")
+        add_compile_options(
+            --target=arm-arm-none-eabi
+            -Wno-ignored-optimization-argument
+            -Wno-unused-command-line-argument
+            -c
+            -fdata-sections
+            -ffunction-sections
+            -fno-builtin
+            -fshort-enums
+            -fshort-wchar
+            -funsigned-char
+            -masm=auto
+            -nostdlib
+            -std=c99
+            $<$<NOT:$<BOOL:${TFM_SYSTEM_FP}>>:-mfpu=none>
+        )
+    else()
+        # Compile options for legacy compiler 6.10.1. To be removed as soon that
+        # that compiler can be deprecated.
+        add_compile_options(
+            $<$<COMPILE_LANGUAGE:C>:--target=arm-arm-none-eabi>
+            $<$<COMPILE_LANGUAGE:C>:-Wno-ignored-optimization-argument>
+            $<$<COMPILE_LANGUAGE:C>:-Wno-unused-command-line-argument>
+            $<$<COMPILE_LANGUAGE:C>:-Wall>
+            # Don't error when the MBEDTLS_NULL_ENTROPY warning is shown
+            $<$<COMPILE_LANGUAGE:C>:-Wno-error=cpp>
+            $<$<COMPILE_LANGUAGE:C>:-c>
+            $<$<COMPILE_LANGUAGE:C>:-fdata-sections>
+            $<$<COMPILE_LANGUAGE:C>:-ffunction-sections>
+            $<$<COMPILE_LANGUAGE:C>:-fno-builtin>
+            $<$<COMPILE_LANGUAGE:C>:-fshort-enums>
+            $<$<COMPILE_LANGUAGE:C>:-fshort-wchar>
+            $<$<COMPILE_LANGUAGE:C>:-funsigned-char>
+            $<$<COMPILE_LANGUAGE:C>:-masm=auto>
+            $<$<COMPILE_LANGUAGE:C>:-nostdlib>
+            $<$<COMPILE_LANGUAGE:C>:-std=c99>
+            $<$<AND:$<COMPILE_LANGUAGE:C>,$<NOT:$<BOOL:${TFM_SYSTEM_FP}>>>:-mfpu=none>
+            $<$<COMPILE_LANGUAGE:ASM>:--cpu=${CMAKE_SYSTEM_PROCESSOR}>
+            $<$<AND:$<COMPILE_LANGUAGE:ASM>,$<NOT:$<BOOL:${TFM_SYSTEM_FP}>>>:--fpu=none>
+        )
+        set(COMPILER_CMSE_FLAG $<$<COMPILE_LANGUAGE:C>:-mcmse>)
+    endif()
+    add_link_options(
+        --info=summarysizes,sizes,totals,unused,veneers
+        --strict
+        --symbols
+        --xref
+        # Suppress link warnings that are consistant (and therefore hopefully
+        # harmless)
+        # https://developer.arm.com/documentation/100074/0608/linker-errors-and-warnings/list-of-the-armlink-error-and-warning-messages
+        # Empty region description
+        --diag_suppress=6312
+        # Ns section matches pattern
+        --diag_suppress=6314
+        # Duplicate input files
+        --diag_suppress=6304
+        $<$<NOT:$<BOOL:${TFM_SYSTEM_FP}>>:--fpu=softvfp>
+    )
+
+    if (DEFINED TFM_SYSTEM_FP)
+        if(TFM_SYSTEM_FP)
+            # TODO Whether a system requires these extensions appears to depend
+            # on the system in question, with no real rule. Since adding +fp
+            # will cause compile failures on systems that already have fp
+            # enabled, this is commented out for now to avoid those failures. In
+            # future, better handling should be implemented.
+            # string(APPEND CMAKE_SYSTEM_PROCESSOR "+fp")
+        else()
+            string(APPEND CMAKE_SYSTEM_PROCESSOR "+nofp")
+        endif()
+    endif()
+
+    if (DEFINED TFM_SYSTEM_DSP)
+        if(TFM_SYSTEM_DSP)
+            # TODO Whether a system requires these extensions appears to depend
+            # on the system in question, with no real rule. Since adding +dsp
+            # will cause compile failures on systems that already have dsp
+            # enabled, this is commented out for now to avoid those failures. In
+            # future, better handling should be implemented.
+            # string(APPEND CMAKE_SYSTEM_PROCESSOR "+dsp")
+        else()
+            string(APPEND CMAKE_SYSTEM_PROCESSOR "+nodsp")
+        endif()
+    endif()
+
+    unset(CMAKE_C_FLAGS_INIT)
+    unset(CMAKE_C_LINK_FLAGS)
+    unset(CMAKE_ASM_FLAGS_INIT)
+    unset(CMAKE_ASM_LINK_FLAGS)
+
+    # cmake does not allow the use of +dsp / +nofpu syntax. An override is added
+    # here to enable it. First reset the supported CPU list in case this has
+    # already been run.
+    __armclang_set_processor_list(C CMAKE_C_COMPILER_PROCESSOR_LIST)
+    __armclang_set_processor_list(ASM CMAKE_ASM_COMPILER_PROCESSOR_LIST)
+    # Then use regex to add +dsp +nodsp +fpu and +nofp options
+    # TODO generate this combinatorially
+    list(TRANSFORM CMAKE_C_COMPILER_PROCESSOR_LIST REPLACE "^(.+)$" "\\1;\\1+fp;\\1+nofp;")
+    list(TRANSFORM CMAKE_C_COMPILER_PROCESSOR_LIST REPLACE "^(.+)$" "\\1;\\1+dsp;\\1+nodsp;")
+    list(TRANSFORM CMAKE_ASM_COMPILER_PROCESSOR_LIST REPLACE "^(.+)$" "\\1;\\1+fp;\\1+nofp;")
+    list(TRANSFORM CMAKE_ASM_COMPILER_PROCESSOR_LIST REPLACE "^(.+)$" "\\1;\\1+dsp;\\1+nodsp;")
+
+    __compiler_armclang(C)
+
+    if(${CMAKE_C_COMPILER_VERSION} VERSION_GREATER_EQUAL "6.11")
+        __compiler_armclang(ASM)
+    else()
+        # Because armclang<6.11 does not have an integrated assembler that
+        # supports the ASM syntax used by the CMSIS startup files, it is
+        # required to manuall invoke armasm. CMake does not support that when
+        # using armclang as the declared compiler, so instead we use some of the
+        # internals from ArmCC which uses armasm by default.
+        find_program(ARMASM_PATH armasm HINTS "${_CMAKE_C_TOOLCHAIN_LOCATION}")
+        set(CMAKE_ASM_COMPILER ${ARMASM_PATH})
+        include(${CMAKE_ROOT}/Modules/Compiler/ARMCC.cmake)
+        include(${CMAKE_ROOT}/Modules/Compiler/ARMCC-ASM.cmake)
+        __compiler_armcc(ASM)
+    endif()
+
+    set(CMAKE_C_FLAGS ${CMAKE_C_FLAGS_INIT})
+    set(CMAKE_ASM_FLAGS ${CMAKE_ASM_FLAGS_INIT})
+
+    # But armlink doesn't support this +dsp syntax, so take the cpu flag and
+    # throw away the plus and everything after.
+    string(REGEX REPLACE "(--cpu=.*)\\+[a-z\\+]*[ ]?" "\\1" CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS}")
+    string(REGEX REPLACE "(--cpu=.*)\\+[a-z\\+]*[ ]?" "\\1" CMAKE_ASM_LINK_FLAGS "${CMAKE_ASM_LINK_FLAGS}")
+endmacro()
+
+# Behaviour for handling scatter files is so wildly divergent between compilers
+# that this macro is required.
+macro(target_add_scatter_file target)
+    target_link_options(${target}
+        PRIVATE
+        --scatter=$<TARGET_OBJECTS:${target}_scatter>
+    )
+
+    add_dependencies(${target}
+        ${target}_scatter
+    )
+
+    add_library(${target}_scatter OBJECT)
+    foreach(scatter_file ${ARGN})
+        target_sources(${target}_scatter
+            PRIVATE
+                ${scatter_file}
+        )
+        # Cmake cannot use generator expressions in the
+        # set_source_file_properties command, so instead we just parse the regex
+        # for the filename and set the property on all files, regardless of if
+        # the generator expression would evaluate to true or not.
+        string(REGEX REPLACE ".*>:(.*)>$" "\\1" SCATTER_FILE_PATH "${scatter_file}")
+        set_source_files_properties(${SCATTER_FILE_PATH}
+            PROPERTIES
+            LANGUAGE C
+        )
+    endforeach()
+
+    set_target_properties(${target}_scatter PROPERTIES
+        SUFFIX ".ld"
+    )
+
+    target_link_libraries(${target}_scatter
+        platform_region_defs
+        psa_interface
+        tfm_partition_defs
+    )
+
+    target_compile_options(${target}_scatter
+        PRIVATE
+            -E
+            -xc
+    )
+endmacro()
+
+macro(add_convert_to_bin_target target)
+    get_target_property(bin_dir ${target} RUNTIME_OUTPUT_DIRECTORY)
+
+    add_custom_target(${target}_bin
+        SOURCES ${bin_dir}/${target}.bin
+    )
+    add_custom_command(OUTPUT ${bin_dir}/${target}.bin
+        DEPENDS ${target}
+        COMMAND fromelf
+            --bincombined $<TARGET_FILE:${target}>
+            --output=${bin_dir}/${target}.bin
+    )
+
+    add_custom_target(${target}_elf
+        SOURCES ${bin_dir}/${target}.elf
+    )
+    add_custom_command(OUTPUT ${bin_dir}/${target}.elf
+        DEPENDS ${target}
+        COMMAND fromelf
+            --elf $<TARGET_FILE:${target}>
+            --output=${bin_dir}/${target}.elf
+    )
+
+    add_custom_target(${target}_hex
+        SOURCES ${bin_dir}/${target}.hex
+    )
+    add_custom_command(OUTPUT ${bin_dir}/${target}.hex
+        DEPENDS ${target}
+        COMMAND fromelf
+            --i32combined $<TARGET_FILE:${target}>
+            --output=${bin_dir}/${target}.hex
+    )
+
+    add_custom_target(${target}_binaries
+        ALL
+        DEPENDS ${target}_bin
+        DEPENDS ${target}_elf
+        DEPENDS ${target}_hex
+    )
+endmacro()