vxge: Fix a receive stall due to driver being out of synch with chip.

- Fix a receive stall due to driver being out of synch with chip. In a corner
case scenario the adapter's ring controller may return a RxD with transfer code
of 0xC, while the host ownership bit is still set to the adapter. The driver
needs to assume that this case where (host_ownership == 1 or adapter) and
(transfer_code == 0xC) is valid, that is, this RxD has been returned by the
receive ring controller but no frame data is associated with the rxd.

- Restore the transfer code field of each newly replenished RxD to 0x0.

- Code cleanup. Removed usage of magic numbers.

Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@neterion.com>
Signed-off-by: Ramkrishna Vepa <ram.vepa@neterion.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxge/vxge-traffic.c

@@ -878,7 +878,7 @@ void vxge_hw_ring_rxd_post_post(struct __vxge_hw_ring *ring, void *rxdh)
 
 	channel = &ring->channel;
 
-	rxdp->control_0	|= VXGE_HW_RING_RXD_LIST_OWN_ADAPTER;
+	rxdp->control_0	= VXGE_HW_RING_RXD_LIST_OWN_ADAPTER;
 
 	if (ring->stats->common_stats.usage_cnt > 0)
 		ring->stats->common_stats.usage_cnt--;
@@ -902,7 +902,7 @@ void vxge_hw_ring_rxd_post(struct __vxge_hw_ring *ring, void *rxdh)
 	channel = &ring->channel;
 
 	wmb();
-	rxdp->control_0	|= VXGE_HW_RING_RXD_LIST_OWN_ADAPTER;
+	rxdp->control_0	= VXGE_HW_RING_RXD_LIST_OWN_ADAPTER;
 
 	vxge_hw_channel_dtr_post(channel, rxdh);
 
@@ -966,6 +966,7 @@ enum vxge_hw_status vxge_hw_ring_rxd_next_completed(
 	struct __vxge_hw_channel *channel;
 	struct vxge_hw_ring_rxd_1 *rxdp;
 	enum vxge_hw_status status = VXGE_HW_OK;
+	u64 control_0, own;
 
 	channel = &ring->channel;
 
@@ -977,8 +978,12 @@ enum vxge_hw_status vxge_hw_ring_rxd_next_completed(
 		goto exit;
 	}
 
+	control_0 = rxdp->control_0;
+	own = control_0 & VXGE_HW_RING_RXD_LIST_OWN_ADAPTER;
+	*t_code	= (u8)VXGE_HW_RING_RXD_T_CODE_GET(control_0);
+
 	/* check whether it is not the end */
-	if (!(rxdp->control_0 &	VXGE_HW_RING_RXD_LIST_OWN_ADAPTER)) {
+	if (!own || ((*t_code == VXGE_HW_RING_T_CODE_FRM_DROP) && own)) {
 
 		vxge_assert(((struct vxge_hw_ring_rxd_1 *)rxdp)->host_control !=
 				0);
@@ -986,8 +991,6 @@ enum vxge_hw_status vxge_hw_ring_rxd_next_completed(
 		++ring->cmpl_cnt;
 		vxge_hw_channel_dtr_complete(channel);
 
-		*t_code	= (u8)VXGE_HW_RING_RXD_T_CODE_GET(rxdp->control_0);
-
 		vxge_assert(*t_code != VXGE_HW_RING_RXD_T_CODE_UNUSED);
 
 		ring->stats->common_stats.usage_cnt++;
@@ -1035,12 +1038,13 @@ enum vxge_hw_status vxge_hw_ring_handle_tcode(
 	 * such as unknown UPV6 header), Drop it !!!
 	 */
 
-	if (t_code == 0 || t_code == 5) {
+	if (t_code ==  VXGE_HW_RING_T_CODE_OK ||
+		t_code == VXGE_HW_RING_T_CODE_L3_PKT_ERR) {
 		status = VXGE_HW_OK;
 		goto exit;
 	}
 
-	if (t_code > 0xF) {
+	if (t_code > VXGE_HW_RING_T_CODE_MULTI_ERR) {
 		status = VXGE_HW_ERR_INVALID_TCODE;
 		goto exit;
 	}

drivers/net/vxge/vxge-traffic.h

@@ -1866,6 +1866,51 @@ struct vxge_hw_ring_rxd_info {
 	u32	rth_hash_type;
 	u32	rth_value;
 };
+/**
+ * enum vxge_hw_ring_tcode - Transfer codes returned by adapter
+ * @VXGE_HW_RING_T_CODE_OK: Transfer ok.
+ * @VXGE_HW_RING_T_CODE_L3_CKSUM_MISMATCH: Layer 3 checksum presentation
+ *		configuration mismatch.
+ * @VXGE_HW_RING_T_CODE_L4_CKSUM_MISMATCH: Layer 4 checksum presentation
+ *		configuration mismatch.
+ * @VXGE_HW_RING_T_CODE_L3_L4_CKSUM_MISMATCH: Layer 3 and Layer 4 checksum
+ *		presentation configuration mismatch.
+ * @VXGE_HW_RING_T_CODE_L3_PKT_ERR: Layer 3 error unparseable packet,
+ *		such as unknown IPv6 header.
+ * @VXGE_HW_RING_T_CODE_L2_FRM_ERR: Layer 2 error frame integrity
+ *		error, such as FCS or ECC).
+ * @VXGE_HW_RING_T_CODE_BUF_SIZE_ERR: Buffer size error the RxD buffer(
+ *		s) were not appropriately sized and data loss occurred.
+ * @VXGE_HW_RING_T_CODE_INT_ECC_ERR: Internal ECC error RxD corrupted.
+ * @VXGE_HW_RING_T_CODE_BENIGN_OVFLOW: Benign overflow the contents of
+ *		Segment1 exceeded the capacity of Buffer1 and the remainder
+ *		was placed in Buffer2. Segment2 now starts in Buffer3.
+ *		No data loss or errors occurred.
+ * @VXGE_HW_RING_T_CODE_ZERO_LEN_BUFF: Buffer size 0 one of the RxDs
+ *		assigned buffers has a size of 0 bytes.
+ * @VXGE_HW_RING_T_CODE_FRM_DROP: Frame dropped either due to
+ *		VPath Reset or because of a VPIN mismatch.
+ * @VXGE_HW_RING_T_CODE_UNUSED: Unused
+ * @VXGE_HW_RING_T_CODE_MULTI_ERR: Multiple errors more than one
+ *		transfer code condition occurred.
+ *
+ * Transfer codes returned by adapter.
+ */
+enum vxge_hw_ring_tcode {
+	VXGE_HW_RING_T_CODE_OK				= 0x0,
+	VXGE_HW_RING_T_CODE_L3_CKSUM_MISMATCH		= 0x1,
+	VXGE_HW_RING_T_CODE_L4_CKSUM_MISMATCH		= 0x2,
+	VXGE_HW_RING_T_CODE_L3_L4_CKSUM_MISMATCH	= 0x3,
+	VXGE_HW_RING_T_CODE_L3_PKT_ERR			= 0x5,
+	VXGE_HW_RING_T_CODE_L2_FRM_ERR			= 0x6,
+	VXGE_HW_RING_T_CODE_BUF_SIZE_ERR		= 0x7,
+	VXGE_HW_RING_T_CODE_INT_ECC_ERR			= 0x8,
+	VXGE_HW_RING_T_CODE_BENIGN_OVFLOW		= 0x9,
+	VXGE_HW_RING_T_CODE_ZERO_LEN_BUFF		= 0xA,
+	VXGE_HW_RING_T_CODE_FRM_DROP			= 0xC,
+	VXGE_HW_RING_T_CODE_UNUSED			= 0xE,
+	VXGE_HW_RING_T_CODE_MULTI_ERR			= 0xF
+};
 
 /**
  * enum enum vxge_hw_ring_hash_type - RTH hash types