ipmi: start implementing flashStartTransfer

Change-Id: I1f8b1498d517c0661e98b1ba895e7152f7a9ed8e
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/ipmi.cpp b/ipmi.cpp
new file mode 100644
index 0000000..65a719a
--- /dev/null
+++ b/ipmi.cpp
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * 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 "flash-ipmi.hpp"
+#include "ipmi.hpp"
+
+ipmi_ret_t startTransfer(UpdateInterface* updater, const uint8_t* reqBuf,
+                         uint8_t* replyBuf, size_t* dataLen)
+{
+    /* Validate the request buffer. */
+    if (sizeof(struct StartTx) > (*dataLen))
+    {
+        return IPMI_CC_INVALID;
+    }
+
+    auto request = reinterpret_cast<const struct StartTx*>(reqBuf);
+
+    if (!updater->start(request->length))
+    {
+        return IPMI_CC_INVALID;
+    }
+
+    /* We were successful and set the response byte to 0. */
+    replyBuf[0] = 0x00;
+    (*dataLen) = 1;
+    return IPMI_CC_OK;
+}