net/ncsi: NCSI command packet handler

The NCSI command packets are sent from MC (Management Controller)
to remote end. They are used for multiple purposes: probe existing
NCSI package/channel, retrieve NCSI channel's capability, configure
NCSI channel etc.

This defines struct to represent NCSI command packets and introduces
function ncsi_xmit_cmd(), which will be used to transmit NCSI command
packet according to the request. The request is represented by struct
ncsi_cmd_arg.

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>

include/uapi/linux/if_ether.h

@@ -87,6 +87,7 @@
 #define ETH_P_8021AH	0x88E7          /* 802.1ah Backbone Service Tag */
 #define ETH_P_MVRP	0x88F5          /* 802.1Q MVRP                  */
 #define ETH_P_1588	0x88F7		/* IEEE 1588 Timesync */
+#define ETH_P_NCSI	0x88F8		/* NCSI protocol		*/
 #define ETH_P_PRP	0x88FB		/* IEC 62439-3 PRP/HSRv0	*/
 #define ETH_P_FCOE	0x8906		/* Fibre Channel over Ethernet  */
 #define ETH_P_TDLS	0x890D          /* TDLS */

net/ncsi/Makefile

@@ -1,4 +1,4 @@
 #
 # Makefile for NCSI API
 #
-obj-$(CONFIG_NET_NCSI) += ncsi-manage.o
+obj-$(CONFIG_NET_NCSI) += ncsi-cmd.o ncsi-manage.o

net/ncsi/internal.h

@@ -220,6 +220,21 @@ struct ncsi_dev_priv {
 	struct list_head    node;            /* Form NCSI device list      */
 };
 
+struct ncsi_cmd_arg {
+	struct ncsi_dev_priv *ndp;        /* Associated NCSI device        */
+	unsigned char        type;        /* Command in the NCSI packet    */
+	unsigned char        id;          /* Request ID (sequence number)  */
+	unsigned char        package;     /* Destination package ID        */
+	unsigned char        channel;     /* Detination channel ID or 0x1f */
+	unsigned short       payload;     /* Command packet payload length */
+	bool                 driven;      /* Drive the state machine?      */
+	union {
+		unsigned char  bytes[16]; /* Command packet specific data  */
+		unsigned short words[8];
+		unsigned int   dwords[4];
+	};
+};
+
 extern struct list_head ncsi_dev_list;
 extern spinlock_t ncsi_dev_lock;
 
@@ -253,4 +268,8 @@ struct ncsi_request *ncsi_alloc_request(struct ncsi_dev_priv *ndp, bool driven);
 void ncsi_free_request(struct ncsi_request *nr);
 struct ncsi_dev *ncsi_find_dev(struct net_device *dev);
 
+/* Packet handlers */
+u32 ncsi_calculate_checksum(unsigned char *data, int len);
+int ncsi_xmit_cmd(struct ncsi_cmd_arg *nca);
+
 #endif /* __NCSI_INTERNAL_H__ */