[bazel] Automatically download bitstreams for FPGA tests
1. Create a bitstreams repository to cache bitstreams published in the
GCP opentitan-bitstreams bucket.
2. Create a manager script which periodically examines the list of
published bitstreams and downloads the latest (or user requested)
and creates bazel labels for those bitstreams.
3. Update the cw310 rule to depend on @bitstreams//:bitstream_test_rom.
This can be changed to @bitstreams//:bitstream_mask_rom for tests
which require the mask ROM.
Signed-off-by: Chris Frantz <cfrantz@google.com>
diff --git a/rules/bitstreams.bzl b/rules/bitstreams.bzl
new file mode 100644
index 0000000..e7dfdef
--- /dev/null
+++ b/rules/bitstreams.bzl
@@ -0,0 +1,71 @@
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+load("@python3//:defs.bzl", "interpreter")
+
+def _bitstreams_repo_impl(rctx):
+ rctx.execute(
+ [
+ rctx.path(rctx.attr.python_interpreter),
+ rctx.attr._cache_manager,
+ "--build-file=BUILD.bazel",
+ "--bucket-url={}".format(rctx.attr.bucket_url),
+ "--cache={}".format(rctx.attr.cache),
+ "--refresh-time={}".format(rctx.attr.refresh_time),
+ ],
+ quiet = False,
+ )
+
+# The bitstream repo is evaluated on every invocation of bazel.
+# Once the cache is initialized, a typical invocation will find the latest
+# cached bitstream and configure it for use as a test artifact.
+#
+# The `refresh_time` sets the interval at which the cache manager will
+# check for new bitstreams.
+#
+# By default, the cache manager will configure the latest available bitstream
+# as the default bitstream. It will refresh every 18 hours.
+#
+# The behavior of the cache manager can be constrolled via the BITSTREAM
+# environment variable. The environment variable can be any command line
+# arguments accepted by the cache manager script.
+#
+# For example, to force a refresh of the cache:
+# BITSTREAM=--refresh bazel build @bitstreams//...
+#
+# To use an exact bitstream in a test:
+# BITSTREAM=3732655dbd225b5c1ae94a79b54cc9dc8cd8e391 bazel test <label>
+#
+# You can use any valid git commit identifier to select a bitstream:
+# BITSTREAM=HEAD~1 bazel test <label>
+#
+# If you ask for a bitstream that does not exist in the GCP bucket, the
+# next oldest bitstream will be chosen.
+bitstreams_repo = repository_rule(
+ implementation = _bitstreams_repo_impl,
+ attrs = {
+ "bucket_url": attr.string(
+ doc = "Location of the GCP bitstream bucket.",
+ default = "https://storage.googleapis.com/opentitan-bitstreams/",
+ ),
+ "cache": attr.string(
+ doc = "Location of bitstreams cache.",
+ default = "~/.cache/opentitan-bitstreams",
+ ),
+ "refresh_time": attr.int(
+ doc = "How often to check for new bitstreams (seconds).",
+ default = 18 * 3600, # Refresh every 18h
+ ),
+ "python_interpreter": attr.label(
+ default = interpreter,
+ allow_single_file = True,
+ doc = "Python interpreter to use.",
+ ),
+ "_cache_manager": attr.label(
+ default = Label("//rules/scripts:bitstreams_workspace.py"),
+ allow_files = True,
+ ),
+ },
+ environ = ["BITSTREAM"],
+ local = True,
+)
