mboxd: Update mboxd to implement protocol V2 and add dbus support

Version 2 of the mbox protocol contains a few changes such as:
 - All sizes are in block size
 - Adds an erase command
 - Adds new response codes
 - Adds new BMC events
 - Open windows commands now take a size directive

Update the mailbox daemon to support version 2 of the protocol which
includes implementing all of the V2 functionality. Also entirely refactor
the mboxd.c code to make it more modular improving readability and
maintainability.

At the same time improve the functionality by adding:
 - Multiple windows in the daemon (still only one active window) to cache
   flash contents
 - Implement a dbus interface to allow interaction with the daemon
 - Handle sigterm and sigint and terminate cleanly

The previous implementation utilised the entire reserved memory region.
Update the daemon so that on the command line the number of windows and
the size of each which the reserved memory region will be split into can
be specified. The reserved memory region is then divided between the
windows, however there can still only be one "active" window at a time.
The daemon uses these windows to cache the flash contents meaning the
flash doesn't have to be copied when the host requests access assuming
the daemon already has a copy.

A dbus interface is added so that commands can be sent to the daemon to
control it's operation from the bmc. These include suspending and resuming
the daemon to synchronise flash access, telling the daemon to point the lpc
mapping back to flash and telling the daemon when the flash has been
modified out from under it.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Change-Id: I10be01a395c2bec437cf2c825fdd144580b60dbc
diff --git a/dbus.h b/dbus.h
new file mode 100644
index 0000000..4e5aa04
--- /dev/null
+++ b/dbus.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2016 IBM
+ *
+ * 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.
+ *
+ */
+
+#ifndef MBOX_DBUS_H
+#define MBOX_DBUS_H
+
+#define DBUS_NAME		"org.openbmc.mboxd"
+#define DOBJ_NAME		"/org/openbmc/mboxd"
+
+/* Commands */
+#define DBUS_C_PING		0x00
+#define	DBUS_C_DAEMON_STATE	0x01
+#define DBUS_C_RESET		0x02
+#define DBUS_C_SUSPEND		0x03
+#define DBUS_C_RESUME		0x04
+#define DBUS_C_MODIFIED		0x05
+#define DBUS_C_KILL		0x06
+#define DBUS_C_LPC_STATE	0x07
+#define NUM_DBUS_CMDS		(DBUS_C_LPC_STATE + 1)
+
+/* Command Args */
+/* Resume */
+#define RESUME_NUM_ARGS		1
+#define RESUME_NOT_MODIFIED	0x00
+#define RESUME_FLASH_MODIFIED	0x01
+
+/* Return Values */
+#define DBUS_SUCCESS		0x00 /* Command Succeded */
+#define E_DBUS_INTERNAL		0x01 /* Internal DBUS Error */
+#define E_DBUS_INVAL		0x02 /* Invalid Command */
+#define E_DBUS_REJECTED		0x03 /* Daemon Rejected Request */
+#define E_DBUS_HARDWARE		0x04 /* BMC Hardware Error */
+
+/* Response Args */
+/* Status */
+#define DAEMON_STATE_NUM_ARGS	1
+#define DAEMON_STATE_ACTIVE	0x00 /* Daemon Active */
+#define DAEMON_STATE_SUSPENDED	0x01 /* Daemon Suspended */
+/* LPC State */
+#define LPC_STATE_NUM_ARGS	1
+#define LPC_STATE_INVALID	0x00 /* Invalid State */
+#define LPC_STATE_FLASH		0x01 /* LPC Maps Flash Directly */
+#define LPC_STATE_MEM		0x02 /* LPC Maps Memory */
+
+struct mbox_dbus_msg {
+	uint8_t cmd;
+	size_t num_args;
+	uint8_t *args;
+};
+
+#endif /* MBOX_DBUS_H */