pcie_bifurcation: Fetch bifurcation at a PCIe slot with hardcoded values
This will read a json config and return the bifurcation based on that.
It will read the configure file in a persistent file to see if it is
valid machine config and return the bifurcation information
accordingly.
For example,
If it is valid config, it will return 8x8 for PE1,3,4,6.
Tested:
Unit tests passed.
Physical Tests.
PE0 -> no bifurcation
PE1 -> x8x8
```
$ ipmitool raw 0x2e 0x32 0x79 0x2b 0x00 0x0f 0
79 2b 00 0b 00
$ ipmitool raw 0x2e 0x32 0x79 0x2b 0x00 0x0f 1
79 2b 00 0b 02 08 08
```
Change-Id: I44aefbfb26372f8bc0069343c8a6d07d3cf6f42d
Signed-off-by: Willy Tu <wltu@google.com>
diff --git a/bifurcation/bifurcation_static.cpp b/bifurcation/bifurcation_static.cpp
new file mode 100644
index 0000000..66b0c9a
--- /dev/null
+++ b/bifurcation/bifurcation_static.cpp
@@ -0,0 +1,91 @@
+// Copyright 2022 Google LLC
+//
+// 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.
+#include "config.h"
+
+#include "bifurcation.hpp"
+
+#include <fmt/format.h>
+
+#include <charconv>
+#include <filesystem>
+#include <fstream>
+#include <nlohmann/json.hpp>
+#include <optional>
+#include <string_view>
+#include <vector>
+
+namespace google
+{
+namespace ipmi
+{
+
+BifurcationStatic::BifurcationStatic() :
+ BifurcationStatic(STATIC_BIFURCATION_CONFIG)
+{
+}
+
+BifurcationStatic::BifurcationStatic(std::string_view bifurcationFile) :
+ bifurcationFile(bifurcationFile)
+{
+}
+
+std::optional<std::vector<uint8_t>>
+ BifurcationStatic::getBifurcation(uint8_t index) noexcept
+{
+ // Example valid data:
+ // {
+ // "1": [8,8],
+ // "2": [4, 4, 12]
+ // }
+ std::ifstream jsonFile(bifurcationFile.c_str());
+ if (!jsonFile.is_open())
+ {
+ fmt::print(stderr, "Unable to open file {} for bifurcation.\n",
+ bifurcationFile.data());
+ return std::nullopt;
+ }
+
+ nlohmann::json jsonData;
+ try
+ {
+ jsonData = nlohmann::json::parse(jsonFile, nullptr, false);
+ }
+ catch (const nlohmann::json::parse_error& ex)
+ {
+ fmt::print(
+ stderr,
+ "Failed to parse the static config. Parse error at byte {}\n",
+ ex.byte);
+ return std::nullopt;
+ }
+
+ std::vector<uint8_t> vec;
+ try
+ {
+ std::string key = std::to_string(index);
+ auto value = jsonData[key];
+ value.get_to(vec);
+ }
+ catch (std::exception const& e)
+ {
+ fmt::print(stderr,
+ "Failed to convert bifurcation value to vec[uin8_t]\n");
+ return std::nullopt;
+ }
+
+ return vec;
+}
+
+} // namespace ipmi
+} // namespace google