[sw] Add Meson as software build system
Overview:
This commit adds the following changes:
* Meson build files for sw/ targets. There are two supported build
configurations:
* build-fpga: Nexys FPGA
* build-sim: Verilator
* RISCV crosstool support via toolchain.txt
* Add util/embedded_target.py to generate additional objects per
embedded_target.
* Breakdown sw/lib/ot_lib.a intp per IP libraries. Each target now
includes the dependencies it needs, e.g. sw_lib_uart_ot can be used to
include the UART device library.
New build system requirements:
```console
$ pip3 install --user meson
$ apt-get install ninja-build
```
Steps for using Meson:
```console
$ cd ${REPO_TOP}
$ ./meson_init.sh
$ ninja -C build-fpga
$ ninja -C build-verilator
```
To build an individual target:
In the following example, just build the flash_test.bin
target:
```console
$ ninja -C build-fpga sw/tests/flash_ctrl/flash_test.bin
```
meson_init.sh configuration options:
* `-f`: Delete build directories before calling meson.
* `-r`: Call Meson with `--reconfigure` flag. Requires valid build
directories.
diff --git a/meson_init.sh b/meson_init.sh
new file mode 100755
index 0000000..6f06bc9
--- /dev/null
+++ b/meson_init.sh
@@ -0,0 +1,76 @@
+#!/bin/bash
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+set -o errexit
+set -o pipefail
+set -o nounset
+
+readonly BUILD_DIR_PREFIX="build"
+readonly TARGET_VERILATOR="verilator"
+readonly TARGET_FPGA="fpga"
+
+function usage() {
+ cat << USAGE
+Configure Meson build targets.
+
+Usage: $0 [-r|-f]
+
+ -f: Remove build directories before running Meson.
+ -r: Force reconfiguration of build directories.
+
+USAGE
+}
+
+FLAGS_force=false
+FLAGS_reconfigure=""
+while getopts 'r?:f?' flag; do
+ case "${flag}" in
+ f) FLAGS_force=true;;
+ r) FLAGS_reconfigure="--reconfigure";;
+ ?) usage && exit 1;;
+ *) usage
+ error "Unexpected option ${flag}"
+ ;;
+ esac
+done
+
+if [[ "${FLAGS_force}" == true && -n "${FLAGS_reconfigure}" ]]; then
+ usage >&2
+ echo "Error: -r and -f cannont be used at the same time." >&2
+ exit 1
+fi
+
+if [[ ! -n "$(command -v meson)" ]]; then
+ echo "Unable to find meson. Please install meson before running this command." >&2
+ exit 1
+fi
+
+if [[ ! -n "$(command -v ninja)" ]]; then
+ echo "Unable to find ninja. Please install ninja before running this command." >&2
+ exit 1
+fi
+
+if [[ "${FLAGS_force}" == true ]]; then
+ for target_suffix in "${TARGET_VERILATOR}" "${TARGET_FPGA}"; do
+ rm -rf "${BUILD_DIR_PREFIX}-${target_suffix}"
+ done
+fi
+
+if [[ ! -n "${FLAGS_reconfigure}" ]] ; then
+ for target_suffix in "${TARGET_VERILATOR}" "${TARGET_FPGA}"; do
+ if [[ -d "${BUILD_DIR_PREFIX}-${target_suffix}" ]]; then
+ usage >&2
+ echo "Error: ${BUILD_DIR_PREFIX}-${target_suffix} already exists. " \
+ "Remove directory, or rerun $0 with the -r option" >&2
+ exit 1
+ fi
+ done
+fi
+
+meson ${FLAGS_reconfigure} "-Dtarget=${TARGET_VERILATOR}" --cross-file=toolchain.txt \
+ --buildtype=plain "${BUILD_DIR_PREFIX}-${TARGET_VERILATOR}"
+
+meson ${FLAGS_reconfigure} "-Dtarget=${TARGET_FPGA}" --cross-file=toolchain.txt \
+ --buildtype=plain "${BUILD_DIR_PREFIX}-${TARGET_FPGA}"
