From 3bbe069bea6a44c520cabd8732b2b7595cb3a718 Mon Sep 17 00:00:00 2001
From: Antoine van Gelder <antoine@greatscottgadgets.com>
Date: Mon, 9 Dec 2024 11:37:46 +0200
Subject: [PATCH] gateware.platform: add support for using yowasp when yosys is
 not available

---
 luna/__init__.py                    |  9 ++++
 luna/gateware/platform/__init__.py  |  5 +-
 luna/gateware/platform/toolchain.py | 72 +++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+), 2 deletions(-)
 create mode 100644 luna/gateware/platform/toolchain.py

diff --git a/luna/__init__.py b/luna/__init__.py
index 453b9d716..ca9e4e81d 100644
--- a/luna/__init__.py
+++ b/luna/__init__.py
@@ -12,6 +12,8 @@
 from amaranth           import Elaboratable
 from amaranth._unused   import MustUse
 
+from luna.gateware.platform import configure_toolchain
+
 # Log formatting strings.
 LOG_FORMAT_COLOR = "\u001b[37;1m%(levelname)-8s| \u001b[0m\u001b[1m%(module)-12s|\u001b[0m %(message)s"
 LOG_FORMAT_PLAIN = "%(levelname)-8s:n%(module)-12s>%(message)s"
@@ -108,8 +110,15 @@ def top_level_cli(fragment, *pos_args, **kwargs):
         join_text = "and uploading gateware to attached" if args.upload else "for"
         logging.info(f"Building {join_text} {platform.name}...")
 
+        # Configure toolchain.
+        if not configure_toolchain(platform):
+            logging.info(f"Failed to configure the toolchain for: {platform.toolchain}")
+            logging.info(f"Continuing anyway.")
+
         # Now that we're actually building, re-enable Unused warnings.
         MustUse._MustUse__silence = False
+
+        # Perform the build.
         products = platform.build(fragment,
             do_program=args.upload,
             build_dir=build_dir
diff --git a/luna/gateware/platform/__init__.py b/luna/gateware/platform/__init__.py
index de1fbc38b..ba1f3f5b1 100644
--- a/luna/gateware/platform/__init__.py
+++ b/luna/gateware/platform/__init__.py
@@ -16,6 +16,7 @@
 from amaranth import Record
 
 from .core import NullPin, LUNAPlatform
+from .toolchain import configure_toolchain
 
 
 def _get_platform_from_string(platform):
@@ -63,11 +64,11 @@ def get_appropriate_platform() -> LUNAPlatform:
             "Unable to autodetect a supported platform. "
             "The LUNA_PLATFORM environment variable must be set.")
     platform = _get_platform_from_string(platform_string)
-    
+
     # If possible, override the platform's device type with the detected FPGA.
     if fpga_device is not None:
         platform.device = fpga_device
-    
+
     return platform
 
 
diff --git a/luna/gateware/platform/toolchain.py b/luna/gateware/platform/toolchain.py
new file mode 100644
index 000000000..ddf32d92e
--- /dev/null
+++ b/luna/gateware/platform/toolchain.py
@@ -0,0 +1,72 @@
+#
+# This file is part of LUNA.
+#
+# Copyright (c) 2020-2024 Great Scott Gadgets <info@greatscottgadgets.com>
+# SPDX-License-Identifier: BSD-3-Clause
+
+""" Utilities for managing LUNA gateware toolchains. """
+
+import importlib
+import logging
+import os
+import shutil
+
+def configure_toolchain(platform):
+    """ Checks if all the required tools for the Yosys toolchain are available.
+
+        If there are missing tools it will attempt to fall back to YoWASP instead.
+
+        Returns:
+            True if a valid toolchain has been configured. Otherwise False.
+    """
+
+    if platform.has_required_tools():
+        # All good, no further hanky-panky required.
+        return True
+
+    # Do we have yowasp available to us?
+    logging.info(f"Failed to locate {platform.toolchain} toolchain, trying YoWASP.")
+    logging.debug("Checking for required tools:")
+    for tool in platform.required_tools:
+        logging.debug(f"    {tool}")
+
+    problems = 0
+
+    # Check whether yowasp-yosys is installed:
+    try:
+        import yowasp_yosys
+        logging.debug(f"Found module: {yowasp_yosys.__name__}")
+    except Exception as e:
+        problems += 1
+        logging.warning(e)
+
+    # Check whether yowasp-nextpnr-<target> is installed:
+    try:
+        nextpnr = next(filter(lambda x: x.startswith("nextpnr-"), platform.required_tools))
+        yowasp_nextpnr = importlib.import_module("yowasp_" + nextpnr.replace('-', '_'))
+        logging.debug(f"Found module: {yowasp_nextpnr.__name__}")
+    except Exception as e:
+        problems += 1
+        logging.warning(e)
+
+    # Check whether the YoWASP binaries are on the system PATH:
+    for tool in platform.required_tools:
+        env_var     = tool.replace('-', '_').upper()
+        yowasp_tool = "yowasp-" + tool
+        path = shutil.which(yowasp_tool)
+        if not path:
+            problems += 1
+            logging.warning(f"'{yowasp_tool}' is not on the system PATH.")
+        else:
+            logging.debug(f'Setting {env_var}="{yowasp_tool}"')
+            os.environ[env_var] = yowasp_tool
+
+    if problems == 0:
+        logging.info("YoWASP configured successfully.")
+    else:
+        logging.info(f"{problems} problems encountered while configuring YoWASP.")
+        logging.info(f"You can install it with:")
+        logging.info(f"    pip install yowasp-yosys yowasp-{nextpnr}")
+        return False
+
+    return True