blob: e442c845f66f54c2641585732fda7ff33368fe5a [file] [log] [blame]
# Copyright 2023 Google LLC
# Copyright lowRISC contributors
#
# 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.
#
# While the code below looks messy, it was taken directly from a vivado example
# See here (https://www.xilinx.com/support/answers/66386.html)
# See also this link (https://github.com/lowRISC/opentitan/pull/8138#issuecomment-916696830)
# for a thorough explanation of why such a custom placement helps.
# Note the placement location was not chosen through any systematic means, but through trial
# and error, it may become necessary in the future to tweak this if other congestion
# issues arise.
## Delete placement constraint for now since it helps timing closure, but will keep the file for now.