net/ncsi: Resource management

NCSI spec (DSP0222) defines several objects: package, channel, mode,
filter, version and statistics etc. This introduces the data structs
to represent those objects and implement functions to manage them.
Also, this introduces CONFIG_NET_NCSI for the newly implemented NCSI
stack.

   * The user (e.g. netdev driver) dereference NCSI device by
     "struct ncsi_dev", which is embedded to "struct ncsi_dev_priv".
     The later one is used by NCSI stack internally.
   * Every NCSI device can have multiple packages simultaneously, up
     to 8 packages. It's represented by "struct ncsi_package" and
     identified by 3-bits ID.
   * Every NCSI package can have multiple channels, up to 32. It's
     represented by "struct ncsi_channel" and identified by 5-bits ID.
   * Every NCSI channel has version, statistics, various modes and
     filters. They are represented by "struct ncsi_channel_version",
     "struct ncsi_channel_stats", "struct ncsi_channel_mode" and
     "struct ncsi_channel_filter" separately.
   * Apart from AEN (Asynchronous Event Notification), the NCSI stack
     works in terms of command and response. This introduces "struct
     ncsi_req" to represent a complete NCSI transaction made of NCSI
     request and response.

link: https://www.dmtf.org/sites/default/files/standards/documents/DSP0222_1.1.0.pdf
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ncsi/Kconfig b/net/ncsi/Kconfig
new file mode 100644
index 0000000..08a8a60
--- /dev/null
+++ b/net/ncsi/Kconfig
@@ -0,0 +1,12 @@
+#
+# Configuration for NCSI support
+#
+
+config NET_NCSI
+	bool "NCSI interface support"
+	depends on INET
+	---help---
+	  This module provides NCSI (Network Controller Sideband Interface)
+	  support. Enable this only if your system connects to a network
+	  device via NCSI and the ethernet driver you're using supports
+	  the protocol explicitly.