net: dsa: tag_qca: add define for handling mgmt Ethernet packet

Add all the required define to prepare support for mgmt read/write in
Ethernet packet. Any packet of this type has to be dropped as the only
use of these special packet is receive ack for an mgmt write request or
receive data for an mgmt read request.
A struct is used that emulates the Ethernet header but is used for a
different purpose.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/dsa/tag_qca.h b/include/linux/dsa/tag_qca.h
index c02d2d3..f366422 100644 (file)
--- a/include/linux/dsa/tag_qca.h
+++ b/include/linux/dsa/tag_qca.h
@@ -12,10 +12,54 @@
 #define QCA_HDR_RECV_FRAME_IS_TAGGED   BIT(3)
 #define QCA_HDR_RECV_SOURCE_PORT       GENMASK(2, 0)
 
+/* Packet type for recv */
+#define QCA_HDR_RECV_TYPE_NORMAL       0x0
+#define QCA_HDR_RECV_TYPE_MIB          0x1
+#define QCA_HDR_RECV_TYPE_RW_REG_ACK   0x2
+
 #define QCA_HDR_XMIT_VERSION           GENMASK(15, 14)
 #define QCA_HDR_XMIT_PRIORITY          GENMASK(13, 11)
 #define QCA_HDR_XMIT_CONTROL           GENMASK(10, 8)
 #define QCA_HDR_XMIT_FROM_CPU          BIT(7)
 #define QCA_HDR_XMIT_DP_BIT            GENMASK(6, 0)
 
+/* Packet type for xmit */
+#define QCA_HDR_XMIT_TYPE_NORMAL       0x0
+#define QCA_HDR_XMIT_TYPE_RW_REG       0x1
+
+/* Check code for a valid mgmt packet. Switch will ignore the packet
+ * with this wrong.
+ */
+#define QCA_HDR_MGMT_CHECK_CODE_VAL    0x5
+
+/* Specific define for in-band MDIO read/write with Ethernet packet */
+#define QCA_HDR_MGMT_SEQ_LEN           4 /* 4 byte for the seq */
+#define QCA_HDR_MGMT_COMMAND_LEN       4 /* 4 byte for the command */
+#define QCA_HDR_MGMT_DATA1_LEN         4 /* First 4 byte for the mdio data */
+#define QCA_HDR_MGMT_HEADER_LEN                (QCA_HDR_MGMT_SEQ_LEN + \
+                                       QCA_HDR_MGMT_COMMAND_LEN + \
+                                       QCA_HDR_MGMT_DATA1_LEN)
+
+#define QCA_HDR_MGMT_DATA2_LEN         12 /* Other 12 byte for the mdio data */
+#define QCA_HDR_MGMT_PADDING_LEN       34 /* Padding to reach the min Ethernet packet */
+
+#define QCA_HDR_MGMT_PKT_LEN           (QCA_HDR_MGMT_HEADER_LEN + \
+                                       QCA_HDR_LEN + \
+                                       QCA_HDR_MGMT_DATA2_LEN + \
+                                       QCA_HDR_MGMT_PADDING_LEN)
+
+#define QCA_HDR_MGMT_SEQ_NUM           GENMASK(31, 0)  /* 63, 32 */
+#define QCA_HDR_MGMT_CHECK_CODE                GENMASK(31, 29) /* 31, 29 */
+#define QCA_HDR_MGMT_CMD               BIT(28)         /* 28 */
+#define QCA_HDR_MGMT_LENGTH            GENMASK(23, 20) /* 23, 20 */
+#define QCA_HDR_MGMT_ADDR              GENMASK(18, 0)  /* 18, 0 */
+
+/* Special struct emulating a Ethernet header */
+struct qca_mgmt_ethhdr {
+       u32 command;            /* command bit 31:0 */
+       u32 seq;                /* seq 63:32 */
+       u32 mdio_data;          /* first 4byte mdio */
+       __be16 hdr;             /* qca hdr */
+} __packed;
+
 #endif /* __TAG_QCA_H */

diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index f8df49d..f17ed5b 100644 (file)
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -32,10 +32,12 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
 
 static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
 {
-       u8 ver;
-       u16  hdr;
-       int port;
+       u8 ver, pk_type;
        __be16 *phdr;
+       int port;
+       u16 hdr;
+
+       BUILD_BUG_ON(sizeof(struct qca_mgmt_ethhdr) != QCA_HDR_MGMT_HEADER_LEN + QCA_HDR_LEN);
 
        if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
                return NULL;
@@ -48,6 +50,13 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
        if (unlikely(ver != QCA_HDR_VERSION))
                return NULL;
 
+       /* Get pk type */
+       pk_type = FIELD_GET(QCA_HDR_RECV_TYPE, hdr);
+
+       /* Ethernet MDIO read/write packet */
+       if (pk_type == QCA_HDR_RECV_TYPE_RW_REG_ACK)
+               return NULL;
+
        /* Remove QCA tag and recalculate checksum */
        skb_pull_rcsum(skb, QCA_HDR_LEN);
        dsa_strip_etype_header(skb, QCA_HDR_LEN);