net: fec: use a union for the buffer descriptors

Using a union gives clearer C code than the existing solution, and
allows the removal of some odd code from the receive path whose
purpose was to merely store the enhanced buffer descriptor.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 130 insertions, 140 deletions

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index a1caee8fd648..e850e7e5118f 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -170,6 +170,11 @@ struct bufdesc_ex {
 	unsigned short res0[4];
 };
 
+union bufdesc_u {
+	struct bufdesc bd;
+	struct bufdesc_ex ebd;
+};
+
 /*
  *	The following definitions courtesy of commproc.h, which where
  *	Copyright (c) 1997 Dan Malek (dmalek@jlc.net).
@@ -288,14 +293,13 @@ struct fec_enet_private {
 	dma_addr_t	rx_bd_dma;
 	dma_addr_t	tx_bd_dma;
 	/* Address of Rx and Tx buffers */
-	struct bufdesc	*rx_bd_base;
-	struct bufdesc	*tx_bd_base;
+	union bufdesc_u	*rx_bd_base;
+	union bufdesc_u	*tx_bd_base;
 	/* The next free ring entry */
-	struct bufdesc	*cur_rx, *cur_tx;
+	union bufdesc_u	*cur_rx, *cur_tx;
 	/* The ring entries to be free()ed */
-	struct bufdesc	*dirty_tx;
+	union bufdesc_u	*dirty_tx;
 
-	unsigned short bufdesc_size;
 	unsigned short tx_ring_size;
 	unsigned short rx_ring_size;
 	unsigned short tx_stop_threshold;
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 27ef27f6994f..c49f2e22e6ee 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -265,68 +265,73 @@ MODULE_PARM_DESC(macaddr, "FEC Ethernet MAC address");
 static int mii_cnt;
 
 static inline
-struct bufdesc *fec_enet_get_nextdesc(struct bufdesc *bdp, struct fec_enet_private *fep)
+union bufdesc_u *fec_enet_get_nextdesc(union bufdesc_u *bdp, struct fec_enet_private *fep)
 {
-	struct bufdesc *new_bd = bdp + 1;
-	struct bufdesc_ex *ex_new_bd = (struct bufdesc_ex *)bdp + 1;
-	struct bufdesc_ex *ex_base;
-	struct bufdesc *base;
+	union bufdesc_u *base;
 	int ring_size;
 
 	if (bdp >= fep->tx_bd_base) {
 		base = fep->tx_bd_base;
 		ring_size = fep->tx_ring_size;
-		ex_base = (struct bufdesc_ex *)fep->tx_bd_base;
 	} else {
 		base = fep->rx_bd_base;
 		ring_size = fep->rx_ring_size;
-		ex_base = (struct bufdesc_ex *)fep->rx_bd_base;
 	}
 
-	if (fep->bufdesc_ex)
-		return (struct bufdesc *)((ex_new_bd >= (ex_base + ring_size)) ?
-			ex_base : ex_new_bd);
-	else
-		return (new_bd >= (base + ring_size)) ?
-			base : new_bd;
+	if (fep->bufdesc_ex) {
+		struct bufdesc_ex *ebd = &bdp->ebd + 1;
+		return ebd >= (&base->ebd + ring_size) ?
+			base : (union bufdesc_u *)ebd;
+	} else {
+		struct bufdesc *bd = &bdp->bd + 1;
+		return bd >= (&base->bd + ring_size) ?
+			base : (union bufdesc_u *)bd;
+	}
 }
 
 static inline
-struct bufdesc *fec_enet_get_prevdesc(struct bufdesc *bdp, struct fec_enet_private *fep)
+union bufdesc_u *fec_enet_get_prevdesc(union bufdesc_u *bdp, struct fec_enet_private *fep)
 {
-	struct bufdesc *new_bd = bdp - 1;
-	struct bufdesc_ex *ex_new_bd = (struct bufdesc_ex *)bdp - 1;
-	struct bufdesc_ex *ex_base;
-	struct bufdesc *base;
+	union bufdesc_u *base;
 	int ring_size;
 
 	if (bdp >= fep->tx_bd_base) {
 		base = fep->tx_bd_base;
 		ring_size = fep->tx_ring_size;
-		ex_base = (struct bufdesc_ex *)fep->tx_bd_base;
 	} else {
 		base = fep->rx_bd_base;
 		ring_size = fep->rx_ring_size;
-		ex_base = (struct bufdesc_ex *)fep->rx_bd_base;
 	}
 
-	if (fep->bufdesc_ex)
-		return (struct bufdesc *)((ex_new_bd < ex_base) ?
-			(ex_new_bd + ring_size) : ex_new_bd);
-	else
-		return (new_bd < base) ? (new_bd + ring_size) : new_bd;
+	if (fep->bufdesc_ex) {
+		struct bufdesc_ex *ebd = &bdp->ebd - 1;
+		return (union bufdesc_u *)(ebd < &base->ebd ?
+			ebd + ring_size : ebd);
+	} else {
+		struct bufdesc *bd = &bdp->bd - 1;
+		return (union bufdesc_u *)(bd < &base->bd ?
+			bd + ring_size : bd);
+	}
 }
 
-static int fec_enet_get_bd_index(struct bufdesc *base, struct bufdesc *bdp,
+static int fec_enet_get_bd_index(union bufdesc_u *base, union bufdesc_u *bdp,
 				struct fec_enet_private *fep)
 {
-	return ((const char *)bdp - (const char *)base) / fep->bufdesc_size;
+	if (fep->bufdesc_ex)
+		return &bdp->ebd - &base->ebd;
+	else
+		return &bdp->bd - &base->bd;
 }
 
 static unsigned int fec_enet_get_free_txdesc_num(struct fec_enet_private *fep)
 {
-	int num = ((const char *)fep->dirty_tx -
-			(const char *)fep->cur_tx) / fep->bufdesc_size;
+	int num;
+
+	if (fep->bufdesc_ex)
+		num = &fep->dirty_tx->ebd - &fep->cur_tx->ebd;
+	else
+		num = &fep->dirty_tx->bd - &fep->cur_tx->bd;
+
 	return num < 0 ? num + fep->tx_ring_size : num;
 }
 
@@ -344,7 +349,7 @@ static void *swap_buffer(void *bufaddr, int len)
 static void fec_dump(struct net_device *ndev)
 {
 	struct fec_enet_private *fep = netdev_priv(ndev);
-	struct bufdesc *bdp = fep->tx_bd_base;
+	union bufdesc_u *bdp = fep->tx_bd_base;
 	unsigned int index = 0;
 
 	netdev_info(ndev, "TX ring dump\n");
@@ -355,7 +360,8 @@ static void fec_dump(struct net_device *ndev)
 			index,
 			bdp == fep->cur_tx ? 'S' : ' ',
 			bdp == fep->dirty_tx ? 'H' : ' ',
-			bdp->cbd_sc, bdp->cbd_bufaddr, bdp->cbd_datlen,
+			bdp->bd.cbd_sc, bdp->bd.cbd_bufaddr,
+			bdp->bd.cbd_datlen,
 			fep->tx_skbuff[index]);
 		bdp = fec_enet_get_nextdesc(bdp, fep);
 		index++;
@@ -394,10 +400,10 @@ fec_enet_clear_csum(struct sk_buff *skb, struct net_device *ndev)
 }
 
 static void
-fec_enet_tx_unmap(struct bufdesc *bdp, struct fec_enet_private *fep)
+fec_enet_tx_unmap(union bufdesc_u *bdp, struct fec_enet_private *fep)
 {
-	dma_addr_t addr = bdp->cbd_bufaddr;
-	size_t length = bdp->cbd_datlen;
+	dma_addr_t addr = bdp->bd.cbd_bufaddr;
+	size_t length = bdp->bd.cbd_datlen;
 
 	dma_unmap_single(&fep->pdev->dev, addr, length, DMA_TO_DEVICE);
 }
@@ -408,8 +414,7 @@ fec_enet_txq_submit_frag_skb(struct sk_buff *skb, struct net_device *ndev)
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	const struct platform_device_id *id_entry =
 				platform_get_device_id(fep->pdev);
-	struct bufdesc *bdp = fep->cur_tx;
-	struct bufdesc_ex *ebdp;
+	union bufdesc_u *bdp = fep->cur_tx;
 	int nr_frags = skb_shinfo(skb)->nr_frags;
 	int frag, frag_len;
 	unsigned short status;
@@ -423,9 +428,8 @@ fec_enet_txq_submit_frag_skb(struct sk_buff *skb, struct net_device *ndev)
 	for (frag = 0; frag < nr_frags; frag++) {
 		this_frag = &skb_shinfo(skb)->frags[frag];
 		bdp = fec_enet_get_nextdesc(bdp, fep);
-		ebdp = (struct bufdesc_ex *)bdp;
 
-		status = bdp->cbd_sc;
+		status = bdp->bd.cbd_sc;
 		status &= ~BD_ENET_TX_STATS;
 		status |= (BD_ENET_TX_TC | BD_ENET_TX_READY);
 		frag_len = skb_shinfo(skb)->frags[frag].size;
@@ -444,8 +448,8 @@ fec_enet_txq_submit_frag_skb(struct sk_buff *skb, struct net_device *ndev)
 		if (fep->bufdesc_ex) {
 			if (skb->ip_summed == CHECKSUM_PARTIAL)
 				estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
-			ebdp->cbd_bdu = 0;
-			ebdp->cbd_esc = estatus;
+			bdp->ebd.cbd_bdu = 0;
+			bdp->ebd.cbd_esc = estatus;
 		}
 
 		bufaddr = page_address(this_frag->page.p) + this_frag->page_offset;
@@ -469,9 +473,9 @@ fec_enet_txq_submit_frag_skb(struct sk_buff *skb, struct net_device *ndev)
 			goto dma_mapping_error;
 		}
 
-		bdp->cbd_bufaddr = addr;
-		bdp->cbd_datlen = frag_len;
-		bdp->cbd_sc = status;
+		bdp->bd.cbd_bufaddr = addr;
+		bdp->bd.cbd_datlen = frag_len;
+		bdp->bd.cbd_sc = status;
 	}
 
 	fep->cur_tx = bdp;
@@ -482,8 +486,8 @@ dma_mapping_error:
 	bdp = fep->cur_tx;
 	for (i = 0; i < frag; i++) {
 		bdp = fec_enet_get_nextdesc(bdp, fep);
-		dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
-				bdp->cbd_datlen, DMA_TO_DEVICE);
+		dma_unmap_single(&fep->pdev->dev, bdp->bd.cbd_bufaddr,
+				bdp->bd.cbd_datlen, DMA_TO_DEVICE);
 	}
 	return NETDEV_TX_OK;
 }
@@ -494,7 +498,7 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 	const struct platform_device_id *id_entry =
 				platform_get_device_id(fep->pdev);
 	int nr_frags = skb_shinfo(skb)->nr_frags;
-	struct bufdesc *bdp, *last_bdp;
+	union bufdesc_u *bdp, *last_bdp;
 	void *bufaddr;
 	dma_addr_t addr;
 	unsigned short status;
@@ -518,7 +522,7 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 
 	/* Fill in a Tx ring entry */
 	bdp = fep->cur_tx;
-	status = bdp->cbd_sc;
+	status = bdp->bd.cbd_sc;
 	status &= ~BD_ENET_TX_STATS;
 
 	/* Set buffer length and buffer pointer */
@@ -559,9 +563,6 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 	}
 
 	if (fep->bufdesc_ex) {
-
-		struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
-
 		if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&
 			fep->hwts_tx_en))
 			skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
@@ -569,8 +570,8 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 		if (skb->ip_summed == CHECKSUM_PARTIAL)
 			estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
 
-		ebdp->cbd_bdu = 0;
-		ebdp->cbd_esc = estatus;
+		bdp->ebd.cbd_bdu = 0;
+		bdp->ebd.cbd_esc = estatus;
 	}
 
 	last_bdp = fep->cur_tx;
@@ -578,8 +579,8 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 	/* Save skb pointer */
 	fep->tx_skbuff[index] = skb;
 
-	bdp->cbd_datlen = buflen;
-	bdp->cbd_bufaddr = addr;
+	bdp->bd.cbd_datlen = buflen;
+	bdp->bd.cbd_bufaddr = addr;
 
 	/*
 	 * We need the preceding stores to the descriptor to complete
@@ -592,7 +593,7 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 	 * it's the last BD of the frame, and to put the CRC on the end.
 	 */
 	status |= (BD_ENET_TX_READY | BD_ENET_TX_TC);
-	bdp->cbd_sc = status;
+	bdp->bd.cbd_sc = status;
 
 	/* If this was the last BD in the ring, start at the beginning again. */
 	bdp = fec_enet_get_nextdesc(last_bdp, fep);
@@ -611,18 +612,17 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 
 static int
 fec_enet_txq_put_data_tso(struct sk_buff *skb, struct net_device *ndev,
-			struct bufdesc *bdp, int index, char *data,
+			union bufdesc_u *bdp, int index, char *data,
 			int size, bool last_tcp, bool is_last)
 {
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	const struct platform_device_id *id_entry =
 				platform_get_device_id(fep->pdev);
-	struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
 	unsigned short status;
 	unsigned int estatus = 0;
 	dma_addr_t addr;
 
-	status = bdp->cbd_sc;
+	status = bdp->bd.cbd_sc;
 	status &= ~BD_ENET_TX_STATS;
 
 	status |= (BD_ENET_TX_TC | BD_ENET_TX_READY);
@@ -644,14 +644,14 @@ fec_enet_txq_put_data_tso(struct sk_buff *skb, struct net_device *ndev,
 		return NETDEV_TX_BUSY;
 	}
 
-	bdp->cbd_datlen = size;
-	bdp->cbd_bufaddr = addr;
+	bdp->bd.cbd_datlen = size;
+	bdp->bd.cbd_bufaddr = addr;
 
 	if (fep->bufdesc_ex) {
 		if (skb->ip_summed == CHECKSUM_PARTIAL)
 			estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
-		ebdp->cbd_bdu = 0;
-		ebdp->cbd_esc = estatus;
+		bdp->ebd.cbd_bdu = 0;
+		bdp->ebd.cbd_esc = estatus;
 	}
 
 	/* Handle the last BD specially */
@@ -660,29 +660,28 @@ fec_enet_txq_put_data_tso(struct sk_buff *skb, struct net_device *ndev,
 	if (is_last) {
 		status |= BD_ENET_TX_INTR;
 		if (fep->bufdesc_ex)
-			ebdp->cbd_esc |= BD_ENET_TX_INT;
+			bdp->ebd.cbd_esc |= BD_ENET_TX_INT;
 	}
 
-	bdp->cbd_sc = status;
+	bdp->bd.cbd_sc = status;
 
 	return 0;
 }
 
 static int
 fec_enet_txq_put_hdr_tso(struct sk_buff *skb, struct net_device *ndev,
-			struct bufdesc *bdp, int index)
+			 union bufdesc_u *bdp, int index)
 {
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	const struct platform_device_id *id_entry =
 				platform_get_device_id(fep->pdev);
 	int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
-	struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
 	void *bufaddr;
 	unsigned long dmabuf;
 	unsigned short status;
 	unsigned int estatus = 0;
 
-	status = bdp->cbd_sc;
+	status = bdp->bd.cbd_sc;
 	status &= ~BD_ENET_TX_STATS;
 	status |= (BD_ENET_TX_TC | BD_ENET_TX_READY);
 
@@ -706,17 +705,17 @@ fec_enet_txq_put_hdr_tso(struct sk_buff *skb, struct net_device *ndev,
 		}
 	}
 
-	bdp->cbd_bufaddr = dmabuf;
-	bdp->cbd_datlen = hdr_len;
+	bdp->bd.cbd_bufaddr = dmabuf;
+	bdp->bd.cbd_datlen = hdr_len;
 
 	if (fep->bufdesc_ex) {
 		if (skb->ip_summed == CHECKSUM_PARTIAL)
 			estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
-		ebdp->cbd_bdu = 0;
-		ebdp->cbd_esc = estatus;
+		bdp->ebd.cbd_bdu = 0;
+		bdp->ebd.cbd_esc = estatus;
 	}
 
-	bdp->cbd_sc = status;
+	bdp->bd.cbd_sc = status;
 
 	return 0;
 }
@@ -726,7 +725,7 @@ static int fec_enet_txq_submit_tso(struct sk_buff *skb, struct net_device *ndev)
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
 	int total_len, data_left;
-	struct bufdesc *bdp = fep->cur_tx;
+	union bufdesc_u *bdp = fep->cur_tx;
 	struct tso_t tso;
 	unsigned int index = 0;
 	int ret;
@@ -823,7 +822,7 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 static void fec_enet_bd_init(struct net_device *dev)
 {
 	struct fec_enet_private *fep = netdev_priv(dev);
-	struct bufdesc *bdp;
+	union bufdesc_u *bdp;
 	unsigned int i;
 
 	/* Initialize the receive buffer descriptors. */
@@ -831,16 +830,16 @@ static void fec_enet_bd_init(struct net_device *dev)
 	for (i = 0; i < fep->rx_ring_size; i++) {
 
 		/* Initialize the BD for every fragment in the page. */
-		if (bdp->cbd_bufaddr)
-			bdp->cbd_sc = BD_ENET_RX_EMPTY;
+		if (bdp->bd.cbd_bufaddr)
+			bdp->bd.cbd_sc = BD_ENET_RX_EMPTY;
 		else
-			bdp->cbd_sc = 0;
+			bdp->bd.cbd_sc = 0;
 		bdp = fec_enet_get_nextdesc(bdp, fep);
 	}
 
 	/* Set the last buffer to wrap */
 	bdp = fec_enet_get_prevdesc(bdp, fep);
-	bdp->cbd_sc |= BD_SC_WRAP;
+	bdp->bd.cbd_sc |= BD_SC_WRAP;
 
 	fep->cur_rx = fep->rx_bd_base;
 
@@ -850,10 +849,10 @@ static void fec_enet_bd_init(struct net_device *dev)
 	for (i = 0; i < fep->tx_ring_size; i++) {
 
 		/* Initialize the BD for every fragment in the page. */
-		bdp->cbd_sc = 0;
-		if (bdp->cbd_bufaddr && !IS_TSO_HEADER(fep, bdp->cbd_bufaddr))
+		bdp->bd.cbd_sc = 0;
+		if (bdp->bd.cbd_bufaddr)
 			fec_enet_tx_unmap(bdp, fep);
-		bdp->cbd_bufaddr = 0;
+		bdp->bd.cbd_bufaddr = 0;
 		if (fep->tx_skbuff[i]) {
 			dev_kfree_skb_any(fep->tx_skbuff[i]);
 			fep->tx_skbuff[i] = NULL;
@@ -863,7 +862,7 @@ static void fec_enet_bd_init(struct net_device *dev)
 
 	/* Set the last buffer to wrap */
 	bdp = fec_enet_get_prevdesc(bdp, fep);
-	bdp->cbd_sc |= BD_SC_WRAP;
+	bdp->bd.cbd_sc |= BD_SC_WRAP;
 	fep->dirty_tx = bdp;
 }
 
@@ -1128,7 +1127,7 @@ static void
 fec_enet_tx(struct net_device *ndev)
 {
 	struct	fec_enet_private *fep;
-	struct bufdesc *bdp;
+	union bufdesc_u *bdp;
 	unsigned short status;
 	struct	sk_buff	*skb;
 	int	index = 0;
@@ -1141,7 +1140,7 @@ fec_enet_tx(struct net_device *ndev)
 	bdp = fec_enet_get_nextdesc(bdp, fep);
 
 	pkts_compl = bytes_compl = 0;
-	while (((status = bdp->cbd_sc) & BD_ENET_TX_READY) == 0) {
+	while (((status = bdp->bd.cbd_sc) & BD_ENET_TX_READY) == 0) {
 
 		/* current queue is empty */
 		if (bdp == fep->cur_tx)
@@ -1151,9 +1150,9 @@ fec_enet_tx(struct net_device *ndev)
 
 		skb = fep->tx_skbuff[index];
 		fep->tx_skbuff[index] = NULL;
-		if (!IS_TSO_HEADER(fep, bdp->cbd_bufaddr))
+		if (!IS_TSO_HEADER(fep, bdp->bd.cbd_bufaddr))
 			fec_enet_tx_unmap(bdp, fep);
-		bdp->cbd_bufaddr = 0;
+		bdp->bd.cbd_bufaddr = 0;
 		if (!skb) {
 			bdp = fec_enet_get_nextdesc(bdp, fep);
 			continue;
@@ -1182,9 +1181,8 @@ fec_enet_tx(struct net_device *ndev)
 		if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS) &&
 			fep->bufdesc_ex) {
 			struct skb_shared_hwtstamps shhwtstamps;
-			struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
 
-			fec_enet_hwtstamp(fep, ebdp->ts, &shhwtstamps);
+			fec_enet_hwtstamp(fep, bdp->ebd.ts, &shhwtstamps);
 			skb_tstamp_tx(skb, &shhwtstamps);
 		}
 
@@ -1228,13 +1226,12 @@ fec_enet_rx(struct net_device *ndev, int budget)
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	const struct platform_device_id *id_entry =
 				platform_get_device_id(fep->pdev);
-	struct bufdesc *bdp;
+	union bufdesc_u *bdp;
 	unsigned short status;
 	struct	sk_buff	*skb;
 	ushort	pkt_len;
 	__u8 *data;
 	int	pkt_received = 0;
-	struct	bufdesc_ex *ebdp = NULL;
 	bool	vlan_packet_rcvd = false;
 	u16	vlan_tag;
 	int	index = 0;
@@ -1248,7 +1245,7 @@ fec_enet_rx(struct net_device *ndev, int budget)
 	 */
 	bdp = fep->cur_rx;
 
-	while (!((status = bdp->cbd_sc) & BD_ENET_RX_EMPTY)) {
+	while (!((status = bdp->bd.cbd_sc) & BD_ENET_RX_EMPTY)) {
 
 		if (pkt_received >= budget)
 			break;
@@ -1297,26 +1294,21 @@ fec_enet_rx(struct net_device *ndev, int budget)
 
 		/* Process the incoming frame. */
 		ndev->stats.rx_packets++;
-		pkt_len = bdp->cbd_datlen;
+		pkt_len = bdp->bd.cbd_datlen;
 		ndev->stats.rx_bytes += pkt_len;
 
 		index = fec_enet_get_bd_index(fep->rx_bd_base, bdp, fep);
 		data = fep->rx_skbuff[index]->data;
-		dma_sync_single_for_cpu(&fep->pdev->dev, bdp->cbd_bufaddr,
+		dma_sync_single_for_cpu(&fep->pdev->dev, bdp->bd.cbd_bufaddr,
 					FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE);
 
 		if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
 			swap_buffer(data, pkt_len);
 
-		/* Extract the enhanced buffer descriptor */
-		ebdp = NULL;
-		if (fep->bufdesc_ex)
-			ebdp = (struct bufdesc_ex *)bdp;
-
 		/* If this is a VLAN packet remove the VLAN Tag */
 		vlan_packet_rcvd = false;
 		if ((ndev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
-		    fep->bufdesc_ex && (ebdp->cbd_esc & BD_ENET_RX_VLAN)) {
+		    fep->bufdesc_ex && (bdp->ebd.cbd_esc & BD_ENET_RX_VLAN)) {
 			/* Push and remove the vlan tag */
 			struct vlan_hdr *vlan_header =
 					(struct vlan_hdr *) (data + ETH_HLEN);
@@ -1352,12 +1344,12 @@ fec_enet_rx(struct net_device *ndev, int budget)
 
 			/* Get receive timestamp from the skb */
 			if (fep->hwts_rx_en && fep->bufdesc_ex)
-				fec_enet_hwtstamp(fep, ebdp->ts,
+				fec_enet_hwtstamp(fep, bdp->ebd.ts,
 						  skb_hwtstamps(skb));
 
 			if (fep->bufdesc_ex &&
 			    (fep->csum_flags & FLAG_RX_CSUM_ENABLED)) {
-				if (!(ebdp->cbd_esc & FLAG_RX_CSUM_ERROR)) {
+				if (!(bdp->ebd.cbd_esc & FLAG_RX_CSUM_ERROR)) {
 					/* don't check it */
 					skb->ip_summed = CHECKSUM_UNNECESSARY;
 				} else {
@@ -1374,15 +1366,13 @@ fec_enet_rx(struct net_device *ndev, int budget)
 			napi_gro_receive(&fep->napi, skb);
 		}
 
-		dma_sync_single_for_device(&fep->pdev->dev, bdp->cbd_bufaddr,
+		dma_sync_single_for_device(&fep->pdev->dev, bdp->bd.cbd_bufaddr,
 					FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE);
 rx_processing_done:
 		if (fep->bufdesc_ex) {
-			struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
-
-			ebdp->cbd_esc = BD_ENET_RX_INT;
-			ebdp->cbd_prot = 0;
-			ebdp->cbd_bdu = 0;
+			bdp->ebd.cbd_esc = BD_ENET_RX_INT;
+			bdp->ebd.cbd_prot = 0;
+			bdp->ebd.cbd_bdu = 0;
 		}
 
 		/*
@@ -1396,7 +1386,7 @@ rx_processing_done:
 
 		/* Mark the buffer empty */
 		status |= BD_ENET_RX_EMPTY;
-		bdp->cbd_sc = status;
+		bdp->bd.cbd_sc = status;
 
 		/* Update BD pointer to next entry */
 		bdp = fec_enet_get_nextdesc(bdp, fep);
@@ -2249,14 +2239,14 @@ static void fec_enet_free_buffers(struct net_device *ndev)
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	unsigned int i;
 	struct sk_buff *skb;
-	struct bufdesc	*bdp;
+	union bufdesc_u *bdp;
 
 	bdp = fep->rx_bd_base;
 	for (i = 0; i < fep->rx_ring_size; i++) {
 		skb = fep->rx_skbuff[i];
 		fep->rx_skbuff[i] = NULL;
 		if (skb) {
-			dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
+			dma_unmap_single(&fep->pdev->dev, bdp->bd.cbd_bufaddr,
 					FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE);
 			dev_kfree_skb(skb);
 		}
@@ -2265,9 +2255,9 @@ static void fec_enet_free_buffers(struct net_device *ndev)
 
 	bdp = fep->tx_bd_base;
 	for (i = 0; i < fep->tx_ring_size; i++) {
-		if (bdp->cbd_bufaddr && !IS_TSO_HEADER(fep, bdp->cbd_bufaddr))
+		if (bdp->bd.cbd_bufaddr)
 			fec_enet_tx_unmap(bdp, fep);
-		bdp->cbd_bufaddr = 0;
+		bdp->bd.cbd_bufaddr = 0;
 		kfree(fep->tx_bounce[i]);
 		fep->tx_bounce[i] = NULL;
 		skb = fep->tx_skbuff[i];
@@ -2281,7 +2271,7 @@ static int fec_enet_alloc_buffers(struct net_device *ndev)
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	unsigned int i;
 	struct sk_buff *skb;
-	struct bufdesc	*bdp;
+	union bufdesc_u *bdp;
 
 	bdp = fep->rx_bd_base;
 	for (i = 0; i < fep->rx_ring_size; i++) {
@@ -2301,20 +2291,18 @@ static int fec_enet_alloc_buffers(struct net_device *ndev)
 		}
 
 		fep->rx_skbuff[i] = skb;
-		bdp->cbd_bufaddr = addr;
-		bdp->cbd_sc = BD_ENET_RX_EMPTY;
+		bdp->bd.cbd_bufaddr = addr;
+		bdp->bd.cbd_sc = BD_ENET_RX_EMPTY;
 
-		if (fep->bufdesc_ex) {
-			struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
-			ebdp->cbd_esc = BD_ENET_RX_INT;
-		}
+		if (fep->bufdesc_ex)
+			bdp->ebd.cbd_esc = BD_ENET_RX_INT;
 
 		bdp = fec_enet_get_nextdesc(bdp, fep);
 	}
 
 	/* Set the last buffer to wrap. */
 	bdp = fec_enet_get_prevdesc(bdp, fep);
-	bdp->cbd_sc |= BD_SC_WRAP;
+	bdp->bd.cbd_sc |= BD_SC_WRAP;
 
 	bdp = fep->tx_bd_base;
 	for (i = 0; i < fep->tx_ring_size; i++) {
@@ -2322,20 +2310,18 @@ static int fec_enet_alloc_buffers(struct net_device *ndev)
 		if (!fep->tx_bounce[i])
 			goto err_alloc;
 
-		bdp->cbd_sc = 0;
-		bdp->cbd_bufaddr = 0;
+		bdp->bd.cbd_sc = 0;
+		bdp->bd.cbd_bufaddr = 0;
 
-		if (fep->bufdesc_ex) {
-			struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp;
-			ebdp->cbd_esc = BD_ENET_TX_INT;
-		}
+		if (fep->bufdesc_ex)
+			bdp->ebd.cbd_esc = BD_ENET_TX_INT;
 
 		bdp = fec_enet_get_nextdesc(bdp, fep);
 	}
 
 	/* Set the last buffer to wrap. */
 	bdp = fec_enet_get_prevdesc(bdp, fep);
-	bdp->cbd_sc |= BD_SC_WRAP;
+	bdp->bd.cbd_sc |= BD_SC_WRAP;
 
 	return 0;
 
@@ -2580,7 +2566,7 @@ static int fec_enet_init(struct net_device *ndev)
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	const struct platform_device_id *id_entry =
 				platform_get_device_id(fep->pdev);
-	struct bufdesc *cbd_base;
+	union bufdesc_u *cbd_base;
 	dma_addr_t cbd_dma;
 	int bd_size;
 
@@ -2591,12 +2577,11 @@ static int fec_enet_init(struct net_device *ndev)
 	fep->tx_stop_threshold = FEC_MAX_SKB_DESCS;
 	fep->tx_wake_threshold = (fep->tx_ring_size - fep->tx_stop_threshold) / 2;
 
+	bd_size = fep->tx_ring_size + fep->rx_ring_size;
 	if (fep->bufdesc_ex)
-		fep->bufdesc_size = sizeof(struct bufdesc_ex);
+		bd_size *= sizeof(struct bufdesc_ex);
 	else
-		fep->bufdesc_size = sizeof(struct bufdesc);
-	bd_size = (fep->tx_ring_size + fep->rx_ring_size) *
-			fep->bufdesc_size;
+		bd_size *= sizeof(struct bufdesc);
 
 	/* Allocate memory for buffer descriptors. */
 	cbd_base = dma_alloc_coherent(NULL, bd_size, &cbd_dma, GFP_KERNEL);
@@ -2623,12 +2608,13 @@ static int fec_enet_init(struct net_device *ndev)
 	fep->rx_bd_base = cbd_base;
 	fep->rx_bd_dma = cbd_dma;
 	if (fep->bufdesc_ex) {
-		fep->tx_bd_base = (struct bufdesc *)
-			(((struct bufdesc_ex *)cbd_base) + fep->rx_ring_size);
+		fep->tx_bd_base = (union bufdesc_u *)
+			(&cbd_base->ebd + fep->rx_ring_size);
 		fep->tx_bd_dma = cbd_dma + sizeof(struct bufdesc_ex) *
 			fep->rx_ring_size;
 	} else {
-		fep->tx_bd_base = cbd_base + fep->rx_ring_size;
+		fep->tx_bd_base = (union bufdesc_u *)
+			(&cbd_base->bd + fep->rx_ring_size);
 		fep->tx_bd_dma = cbd_dma + sizeof(struct bufdesc) *
 			fep->rx_ring_size;
 	}