stmmac: support extend descriptors

This patch is to support the extend descriptors available
in the chips newer than the 3.50.

In case of the extend descriptors cannot be supported,
at runtime, the driver will continue to work using the old style.

In detail, this support extends the main descriptor structure
adding new descriptors: 4, 5, 6, 7. The desc4 gives us extra
information about the received ethernet payload when it is
carrying PTP packets or TCP/UDP/ICMP over IP packets.
The descriptors 6 and 7 are used for saving HW L/H timestamps (PTP).

V2: this new version removes the Koption added in the first implementation
because all the checks now to verify if the extended descriptors are
actually supported happen at probe time.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 304 insertions, 139 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index bbee6b32ed63..96fbf86366a9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -468,29 +468,56 @@ static int stmmac_init_phy(struct net_device *dev)
 }
 
 /**
- * display_ring
+ * stmmac_display_ring
  * @p: pointer to the ring.
  * @size: size of the ring.
- * Description: display all the descriptors within the ring.
+ * Description: display the control/status and buffer descriptors.
  */
-static void display_ring(struct dma_desc *p, int size)
+static void stmmac_display_ring(void *head, int size, int extend_desc)
 {
-	struct tmp_s {
-		u64 a;
-		unsigned int b;
-		unsigned int c;
-	};
 	int i;
+	struct dma_extended_desc *ep = (struct dma_extended_desc *) head;
+	struct dma_desc *p = (struct dma_desc *) head;
+
 	for (i = 0; i < size; i++) {
-		struct tmp_s *x = (struct tmp_s *)(p + i);
-		pr_info("\t%d [0x%x]: DES0=0x%x DES1=0x%x BUF1=0x%x BUF2=0x%x",
-		       i, (unsigned int)virt_to_phys(&p[i]),
-		       (unsigned int)(x->a), (unsigned int)((x->a) >> 32),
-		       x->b, x->c);
+		u64 x;
+		if (extend_desc) {
+			x = *(u64 *) ep;
+			pr_info("%d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
+				i, (unsigned int) virt_to_phys(ep),
+				(unsigned int) x, (unsigned int) (x >> 32),
+				ep->basic.des2, ep->basic.des3);
+			ep++;
+		} else {
+			x = *(u64 *) p;
+			pr_info("%d [0x%x]: 0x%x 0x%x 0x%x 0x%x",
+				i, (unsigned int) virt_to_phys(p),
+				(unsigned int) x, (unsigned int) (x >> 32),
+				p->des2, p->des3);
+			p++;
+		}
 		pr_info("\n");
 	}
 }
 
+static void stmmac_display_rings(struct stmmac_priv *priv)
+{
+	unsigned int txsize = priv->dma_tx_size;
+	unsigned int rxsize = priv->dma_rx_size;
+
+	if (priv->extend_desc) {
+		pr_info("Extended RX descriptor ring:\n");
+		stmmac_display_ring((void *) priv->dma_erx, rxsize, 1);
+		pr_info("Extended TX descriptor ring:\n");
+		stmmac_display_ring((void *) priv->dma_etx, txsize, 1);
+	} else {
+		pr_info("RX descriptor ring:\n");
+		stmmac_display_ring((void *)priv->dma_rx, rxsize, 0);
+		pr_info("TX descriptor ring:\n");
+		stmmac_display_ring((void *)priv->dma_tx, txsize, 0);
+	}
+}
+
 static int stmmac_set_bfsize(int mtu, int bufsize)
 {
 	int ret = bufsize;
@@ -507,6 +534,59 @@ static int stmmac_set_bfsize(int mtu, int bufsize)
 	return ret;
 }
 
+static void stmmac_clear_descriptors(struct stmmac_priv *priv)
+{
+	int i;
+	unsigned int txsize = priv->dma_tx_size;
+	unsigned int rxsize = priv->dma_rx_size;
+
+	/* Clear the Rx/Tx descriptors */
+	for (i = 0; i < rxsize; i++)
+		if (priv->extend_desc)
+			priv->hw->desc->init_rx_desc(&priv->dma_erx[i].basic,
+						     priv->use_riwt, priv->mode,
+						     (i == rxsize - 1));
+		else
+			priv->hw->desc->init_rx_desc(&priv->dma_rx[i],
+						     priv->use_riwt, priv->mode,
+						     (i == rxsize - 1));
+	for (i = 0; i < txsize; i++)
+		if (priv->extend_desc)
+			priv->hw->desc->init_tx_desc(&priv->dma_etx[i].basic,
+						     priv->mode,
+						     (i == txsize - 1));
+		else
+			priv->hw->desc->init_tx_desc(&priv->dma_tx[i],
+						     priv->mode,
+						     (i == txsize - 1));
+}
+
+static int stmmac_init_rx_buffers(struct stmmac_priv *priv, struct dma_desc *p,
+				  int i)
+{
+	struct sk_buff *skb;
+
+	skb = __netdev_alloc_skb(priv->dev, priv->dma_buf_sz + NET_IP_ALIGN,
+				 GFP_KERNEL);
+	if (unlikely(skb == NULL)) {
+		pr_err("%s: Rx init fails; skb is NULL\n", __func__);
+		return 1;
+	}
+	skb_reserve(skb, NET_IP_ALIGN);
+	priv->rx_skbuff[i] = skb;
+	priv->rx_skbuff_dma[i] = dma_map_single(priv->device, skb->data,
+						priv->dma_buf_sz,
+						DMA_FROM_DEVICE);
+
+	p->des2 = priv->rx_skbuff_dma[i];
+
+	if ((priv->mode == STMMAC_RING_MODE) &&
+	    (priv->dma_buf_sz == BUF_SIZE_16KiB))
+		priv->hw->ring->init_desc3(p);
+
+	return 0;
+}
+
 /**
  * init_dma_desc_rings - init the RX/TX descriptor rings
  * @dev: net device structure
@@ -518,11 +598,9 @@ static void init_dma_desc_rings(struct net_device *dev)
 {
 	int i;
 	struct stmmac_priv *priv = netdev_priv(dev);
-	struct sk_buff *skb;
 	unsigned int txsize = priv->dma_tx_size;
 	unsigned int rxsize = priv->dma_rx_size;
 	unsigned int bfsize = 0;
-	int dis_ic = 0;
 
 	/* Set the max buffer size according to the DESC mode
 	 * and the MTU. Note that RING mode allows 16KiB bsize. */
@@ -535,50 +613,53 @@ static void init_dma_desc_rings(struct net_device *dev)
 	DBG(probe, INFO, "stmmac: txsize %d, rxsize %d, bfsize %d\n",
 	    txsize, rxsize, bfsize);
 
+	if (priv->extend_desc) {
+		priv->dma_erx = dma_alloc_coherent(priv->device, rxsize *
+						   sizeof(struct
+							  dma_extended_desc),
+						   &priv->dma_rx_phy,
+						   GFP_KERNEL);
+		priv->dma_etx = dma_alloc_coherent(priv->device, txsize *
+						   sizeof(struct
+							  dma_extended_desc),
+						   &priv->dma_tx_phy,
+						   GFP_KERNEL);
+		if ((!priv->dma_erx) || (!priv->dma_etx))
+			return;
+	} else {
+		priv->dma_rx = dma_alloc_coherent(priv->device, rxsize *
+						  sizeof(struct dma_desc),
+						  &priv->dma_rx_phy,
+						  GFP_KERNEL);
+		priv->dma_tx = dma_alloc_coherent(priv->device, txsize *
+						  sizeof(struct dma_desc),
+						  &priv->dma_tx_phy,
+						  GFP_KERNEL);
+		if ((!priv->dma_rx) || (!priv->dma_tx))
+			return;
+	}
+
 	priv->rx_skbuff_dma = kmalloc_array(rxsize, sizeof(dma_addr_t),
 					    GFP_KERNEL);
 	priv->rx_skbuff = kmalloc_array(rxsize, sizeof(struct sk_buff *),
 					GFP_KERNEL);
-	priv->dma_rx = dma_alloc_coherent(priv->device,
-					  rxsize * sizeof(struct dma_desc),
-					  &priv->dma_rx_phy, GFP_KERNEL);
 	priv->tx_skbuff = kmalloc_array(txsize, sizeof(struct sk_buff *),
 					GFP_KERNEL);
-	priv->dma_tx = dma_alloc_coherent(priv->device,
-					  txsize * sizeof(struct dma_desc),
-					  &priv->dma_tx_phy, GFP_KERNEL);
-
-	if ((priv->dma_rx == NULL) || (priv->dma_tx == NULL))
-		return;
-
-	DBG(probe, INFO, "stmmac (%s) DMA desc: virt addr (Rx %p, "
-	    "Tx %p)\n\tDMA phy addr (Rx 0x%08x, Tx 0x%08x)\n",
-	    dev->name, priv->dma_rx, priv->dma_tx,
-	    (unsigned int)priv->dma_rx_phy, (unsigned int)priv->dma_tx_phy);
+	if (netif_msg_drv(priv))
+		pr_debug("(%s) dma_rx_phy=0x%08x dma_tx_phy=0x%08x\n", __func__,
+			 (u32) priv->dma_rx_phy, (u32) priv->dma_tx_phy);
 
 	/* RX INITIALIZATION */
-	DBG(probe, INFO, "stmmac: SKB addresses:\n"
-			 "skb\t\tskb data\tdma data\n");
-
+	DBG(probe, INFO, "stmmac: SKB addresses:\nskb\t\tskb data\tdma data\n");
 	for (i = 0; i < rxsize; i++) {
-		struct dma_desc *p = priv->dma_rx + i;
+		struct dma_desc *p;
+		if (priv->extend_desc)
+			p = &((priv->dma_erx + i)->basic);
+		else
+			p = priv->dma_rx + i;
 
-		skb = __netdev_alloc_skb(dev, bfsize + NET_IP_ALIGN,
-					 GFP_KERNEL);
-		if (unlikely(skb == NULL)) {
-			pr_err("%s: Rx init fails; skb is NULL\n", __func__);
+		if (stmmac_init_rx_buffers(priv, p, i))
 			break;
-		}
-		skb_reserve(skb, NET_IP_ALIGN);
-		priv->rx_skbuff[i] = skb;
-		priv->rx_skbuff_dma[i] = dma_map_single(priv->device, skb->data,
-						bfsize, DMA_FROM_DEVICE);
-
-		p->des2 = priv->rx_skbuff_dma[i];
-
-		if ((priv->mode == STMMAC_RING_MODE) &&
-		    (bfsize == BUF_SIZE_16KiB))
-			priv->hw->ring->init_desc3(p);
 
 		DBG(probe, INFO, "[%p]\t[%p]\t[%x]\n", priv->rx_skbuff[i],
 			priv->rx_skbuff[i]->data, priv->rx_skbuff_dma[i]);
@@ -588,35 +669,39 @@ static void init_dma_desc_rings(struct net_device *dev)
 	priv->dma_buf_sz = bfsize;
 	buf_sz = bfsize;
 
+	/* Setup the chained descriptor addresses */
+	if (priv->mode == STMMAC_CHAIN_MODE) {
+		if (priv->extend_desc) {
+			priv->hw->chain->init(priv->dma_erx, priv->dma_rx_phy,
+					      rxsize, 1);
+			priv->hw->chain->init(priv->dma_etx, priv->dma_tx_phy,
+					      txsize, 1);
+		} else {
+			priv->hw->chain->init(priv->dma_rx, priv->dma_rx_phy,
+					      rxsize, 0);
+			priv->hw->chain->init(priv->dma_tx, priv->dma_tx_phy,
+					      txsize, 0);
+		}
+	}
+
 	/* TX INITIALIZATION */
 	for (i = 0; i < txsize; i++) {
+		struct dma_desc *p;
+		if (priv->extend_desc)
+			p = &((priv->dma_etx + i)->basic);
+		else
+			p = priv->dma_tx + i;
+		p->des2 = 0;
 		priv->tx_skbuff[i] = NULL;
-		priv->dma_tx[i].des2 = 0;
 	}
 
-	/* In case of Chained mode this sets the des3 to the next
-	 * element in the chain */
-	if (priv->mode == STMMAC_CHAIN_MODE) {
-		priv->hw->chain->init_dma_chain(priv->dma_rx, priv->dma_rx_phy,
-						rxsize);
-		priv->hw->chain->init_dma_chain(priv->dma_tx, priv->dma_tx_phy,
-						txsize);
-	}
 	priv->dirty_tx = 0;
 	priv->cur_tx = 0;
 
-	if (priv->use_riwt)
-		dis_ic = 1;
-	/* Clear the Rx/Tx descriptors */
-	priv->hw->desc->init_rx_desc(priv->dma_rx, rxsize, dis_ic, priv->mode);
-	priv->hw->desc->init_tx_desc(priv->dma_tx, txsize, priv->mode);
+	stmmac_clear_descriptors(priv);
 
-	if (netif_msg_hw(priv)) {
-		pr_info("RX descriptor ring:\n");
-		display_ring(priv->dma_rx, rxsize);
-		pr_info("TX descriptor ring:\n");
-		display_ring(priv->dma_tx, txsize);
-	}
+	if (netif_msg_hw(priv))
+		stmmac_display_rings(priv);
 }
 
 static void dma_free_rx_skbufs(struct stmmac_priv *priv)
@@ -639,7 +724,12 @@ static void dma_free_tx_skbufs(struct stmmac_priv *priv)
 
 	for (i = 0; i < priv->dma_tx_size; i++) {
 		if (priv->tx_skbuff[i] != NULL) {
-			struct dma_desc *p = priv->dma_tx + i;
+			struct dma_desc *p;
+			if (priv->extend_desc)
+				p = &((priv->dma_etx + i)->basic);
+			else
+				p = priv->dma_tx + i;
+
 			if (p->des2)
 				dma_unmap_single(priv->device, p->des2,
 						 priv->hw->desc->get_tx_len(p),
@@ -658,12 +748,21 @@ static void free_dma_desc_resources(struct stmmac_priv *priv)
 
 	/* Free the region of consistent memory previously allocated for
 	 * the DMA */
-	dma_free_coherent(priv->device,
-			  priv->dma_tx_size * sizeof(struct dma_desc),
-			  priv->dma_tx, priv->dma_tx_phy);
-	dma_free_coherent(priv->device,
-			  priv->dma_rx_size * sizeof(struct dma_desc),
-			  priv->dma_rx, priv->dma_rx_phy);
+	if (!priv->extend_desc) {
+		dma_free_coherent(priv->device,
+				  priv->dma_tx_size * sizeof(struct dma_desc),
+				  priv->dma_tx, priv->dma_tx_phy);
+		dma_free_coherent(priv->device,
+				  priv->dma_rx_size * sizeof(struct dma_desc),
+				  priv->dma_rx, priv->dma_rx_phy);
+	} else {
+		dma_free_coherent(priv->device, priv->dma_tx_size *
+				  sizeof(struct dma_extended_desc),
+				  priv->dma_etx, priv->dma_tx_phy);
+		dma_free_coherent(priv->device, priv->dma_rx_size *
+				  sizeof(struct dma_extended_desc),
+				  priv->dma_erx, priv->dma_rx_phy);
+	}
 	kfree(priv->rx_skbuff_dma);
 	kfree(priv->rx_skbuff);
 	kfree(priv->tx_skbuff);
@@ -710,13 +809,18 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
 		int last;
 		unsigned int entry = priv->dirty_tx % txsize;
 		struct sk_buff *skb = priv->tx_skbuff[entry];
-		struct dma_desc *p = priv->dma_tx + entry;
+		struct dma_desc *p;
+
+		if (priv->extend_desc)
+			p = (struct dma_desc *) (priv->dma_etx + entry);
+		else
+			p = priv->dma_tx + entry;
 
 		/* Check if the descriptor is owned by the DMA. */
 		if (priv->hw->desc->get_tx_owner(p))
 			break;
 
-		/* Verify tx error by looking at the last segment */
+		/* Verify tx error by looking at the last segment. */
 		last = priv->hw->desc->get_tx_ls(p);
 		if (likely(last)) {
 			int tx_error =
@@ -785,12 +889,21 @@ static inline void stmmac_disable_dma_irq(struct stmmac_priv *priv)
  */
 static void stmmac_tx_err(struct stmmac_priv *priv)
 {
+	int i;
+	int txsize = priv->dma_tx_size;
 	netif_stop_queue(priv->dev);
 
 	priv->hw->dma->stop_tx(priv->ioaddr);
 	dma_free_tx_skbufs(priv);
-	priv->hw->desc->init_tx_desc(priv->dma_tx, priv->dma_tx_size,
-				     priv->mode);
+	for (i = 0; i < txsize; i++)
+		if (priv->extend_desc)
+			priv->hw->desc->init_tx_desc(&priv->dma_etx[i].basic,
+						     priv->mode,
+						     (i == txsize - 1));
+		else
+			priv->hw->desc->init_tx_desc(&priv->dma_tx[i],
+						     priv->mode,
+						     (i == txsize - 1));
 	priv->dirty_tx = 0;
 	priv->cur_tx = 0;
 	priv->hw->dma->start_tx(priv->ioaddr);
@@ -864,6 +977,14 @@ static void stmmac_selec_desc_mode(struct stmmac_priv *priv)
 {
 	if (priv->plat->enh_desc) {
 		pr_info(" Enhanced/Alternate descriptors\n");
+
+		/* GMAC older than 3.50 has no extended descriptors */
+		if (priv->synopsys_id >= DWMAC_CORE_3_50) {
+			pr_info("\tEnabled extended descriptors\n");
+			priv->extend_desc = 1;
+		} else
+			pr_warn("Extended descriptors not supported\n");
+
 		priv->hw->desc = &enh_desc_ops;
 	} else {
 		pr_info(" Normal descriptors\n");
@@ -950,6 +1071,7 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 {
 	int pbl = DEFAULT_DMA_PBL, fixed_burst = 0, burst_len = 0;
 	int mixed_burst = 0;
+	int atds = 0;
 
 	/* Some DMA parameters can be passed from the platform;
 	 * in case of these are not passed we keep a default
@@ -961,9 +1083,12 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 		burst_len = priv->plat->dma_cfg->burst_len;
 	}
 
+	if (priv->extend_desc && (priv->mode == STMMAC_RING_MODE))
+		atds = 1;
+
 	return priv->hw->dma->init(priv->ioaddr, pbl, fixed_burst, mixed_burst,
 				   burst_len, priv->dma_tx_phy,
-				   priv->dma_rx_phy);
+				   priv->dma_rx_phy, atds);
 }
 
 /**
@@ -1237,7 +1362,11 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL);
 
-	desc = priv->dma_tx + entry;
+	if (priv->extend_desc)
+		desc = (struct dma_desc *) (priv->dma_etx + entry);
+	else
+		desc = priv->dma_tx + entry;
+
 	first = desc;
 
 #ifdef STMMAC_XMIT_DEBUG
@@ -1268,14 +1397,17 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 		priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len,
 						csum_insertion, priv->mode);
 	} else
-		desc = priv->dma_tx + entry;
+		desc = first;
 
 	for (i = 0; i < nfrags; i++) {
 		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 		int len = skb_frag_size(frag);
 
 		entry = (++priv->cur_tx) % txsize;
-		desc = priv->dma_tx + entry;
+		if (priv->extend_desc)
+			desc = (struct dma_desc *) (priv->dma_etx + entry);
+		else
+			desc = priv->dma_tx + entry;
 
 		TX_DBG("\t[entry %d] segment len: %d\n", entry, len);
 		desc->des2 = skb_frag_dma_map(priv->device, frag, 0, len,
@@ -1319,7 +1451,11 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 		       "first=%p, nfrags=%d\n",
 		       (priv->cur_tx % txsize), (priv->dirty_tx % txsize),
 		       entry, first, nfrags);
-		display_ring(priv->dma_tx, txsize);
+		if (priv->extend_desc)
+			stmmac_display_ring((void *)priv->dma_etx, txsize, 1);
+		else
+			stmmac_display_ring((void *)priv->dma_tx, txsize, 0);
+
 		pr_info(">>> frame to be transmitted: ");
 		print_pkt(skb->data, skb->len);
 	}
@@ -1344,10 +1480,16 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv)
 {
 	unsigned int rxsize = priv->dma_rx_size;
 	int bfsize = priv->dma_buf_sz;
-	struct dma_desc *p = priv->dma_rx;
 
 	for (; priv->cur_rx - priv->dirty_rx > 0; priv->dirty_rx++) {
 		unsigned int entry = priv->dirty_rx % rxsize;
+		struct dma_desc *p;
+
+		if (priv->extend_desc)
+			p = (struct dma_desc *) (priv->dma_erx + entry);
+		else
+			p = priv->dma_rx + entry;
+
 		if (likely(priv->rx_skbuff[entry] == NULL)) {
 			struct sk_buff *skb;
 
@@ -1361,16 +1503,16 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv)
 			    dma_map_single(priv->device, skb->data, bfsize,
 					   DMA_FROM_DEVICE);
 
-			(p + entry)->des2 = priv->rx_skbuff_dma[entry];
+			p->des2 = priv->rx_skbuff_dma[entry];
 
 			if (unlikely((priv->mode == STMMAC_RING_MODE) &&
 				     (priv->plat->has_gmac)))
-				priv->hw->ring->refill_desc3(bfsize, p + entry);
+				priv->hw->ring->refill_desc3(bfsize, p);
 
 			RX_DBG(KERN_INFO "\trefill entry #%d\n", entry);
 		}
 		wmb();
-		priv->hw->desc->set_rx_owner(p + entry);
+		priv->hw->desc->set_rx_owner(p);
 		wmb();
 	}
 }
@@ -1381,30 +1523,47 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 	unsigned int entry = priv->cur_rx % rxsize;
 	unsigned int next_entry;
 	unsigned int count = 0;
-	struct dma_desc *p = priv->dma_rx + entry;
-	struct dma_desc *p_next;
 
 #ifdef STMMAC_RX_DEBUG
 	if (netif_msg_hw(priv)) {
 		pr_debug(">>> stmmac_rx: descriptor ring:\n");
-		display_ring(priv->dma_rx, rxsize);
+		if (priv->extend_desc)
+			stmmac_display_ring((void *) priv->dma_erx, rxsize, 1);
+		else
+			stmmac_display_ring((void *)priv->dma_rx, rxsize, 0);
 	}
 #endif
-	while (!priv->hw->desc->get_rx_owner(p)) {
+	while (count < limit) {
 		int status;
+		struct dma_desc *p, *p_next;
 
-		if (count >= limit)
+		if (priv->extend_desc)
+			p = (struct dma_desc *) (priv->dma_erx + entry);
+		else
+			p = priv->dma_rx + entry ;
+
+		if (priv->hw->desc->get_rx_owner(p))
 			break;
 
 		count++;
 
 		next_entry = (++priv->cur_rx) % rxsize;
-		p_next = priv->dma_rx + next_entry;
+		if (priv->extend_desc)
+			p_next = (struct dma_desc *) (priv->dma_erx +
+						      next_entry);
+		else
+			p_next = priv->dma_rx + next_entry;
+
 		prefetch(p_next);
 
 		/* read the status of the incoming frame */
-		status = (priv->hw->desc->rx_status(&priv->dev->stats,
-						    &priv->xstats, p));
+		status = priv->hw->desc->rx_status(&priv->dev->stats,
+						   &priv->xstats, p);
+		if ((priv->extend_desc) && (priv->hw->desc->rx_extended_status))
+			priv->hw->desc->rx_extended_status(&priv->dev->stats,
+							   &priv->xstats,
+							   priv->dma_erx +
+							   entry);
 		if (unlikely(status == discard_frame))
 			priv->dev->stats.rx_errors++;
 		else {
@@ -1459,7 +1618,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 			priv->dev->stats.rx_bytes += frame_len;
 		}
 		entry = next_entry;
-		p = p_next;	/* use prefetched values */
 	}
 
 	stmmac_rx_refill(priv);
@@ -1697,40 +1855,51 @@ static struct dentry *stmmac_fs_dir;
 static struct dentry *stmmac_rings_status;
 static struct dentry *stmmac_dma_cap;
 
-static int stmmac_sysfs_ring_read(struct seq_file *seq, void *v)
+static void sysfs_display_ring(void *head, int size, int extend_desc,
+				struct seq_file *seq)
 {
-	struct tmp_s {
-		u64 a;
-		unsigned int b;
-		unsigned int c;
-	};
 	int i;
-	struct net_device *dev = seq->private;
-	struct stmmac_priv *priv = netdev_priv(dev);
-
-	seq_printf(seq, "=======================\n");
-	seq_printf(seq, " RX descriptor ring\n");
-	seq_printf(seq, "=======================\n");
+	struct dma_extended_desc *ep = (struct dma_extended_desc *) head;
+	struct dma_desc *p = (struct dma_desc *) head;
 
-	for (i = 0; i < priv->dma_rx_size; i++) {
-		struct tmp_s *x = (struct tmp_s *)(priv->dma_rx + i);
-		seq_printf(seq, "[%d] DES0=0x%x DES1=0x%x BUF1=0x%x BUF2=0x%x",
-			   i, (unsigned int)(x->a),
-			   (unsigned int)((x->a) >> 32), x->b, x->c);
+	for (i = 0; i < size; i++) {
+		u64 x;
+		if (extend_desc) {
+			x = *(u64 *) ep;
+			seq_printf(seq, "%d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
+				   i, (unsigned int) virt_to_phys(ep),
+				   (unsigned int) x, (unsigned int) (x >> 32),
+				   ep->basic.des2, ep->basic.des3);
+			ep++;
+		} else {
+			x = *(u64 *) p;
+			seq_printf(seq, "%d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
+				   i, (unsigned int) virt_to_phys(ep),
+				   (unsigned int) x, (unsigned int) (x >> 32),
+				   p->des2, p->des3);
+			p++;
+		}
 		seq_printf(seq, "\n");
 	}
+}
 
-	seq_printf(seq, "\n");
-	seq_printf(seq, "=======================\n");
-	seq_printf(seq, "  TX descriptor ring\n");
-	seq_printf(seq, "=======================\n");
+static int stmmac_sysfs_ring_read(struct seq_file *seq, void *v)
+{
+	struct net_device *dev = seq->private;
+	struct stmmac_priv *priv = netdev_priv(dev);
+	unsigned int txsize = priv->dma_tx_size;
+	unsigned int rxsize = priv->dma_rx_size;
 
-	for (i = 0; i < priv->dma_tx_size; i++) {
-		struct tmp_s *x = (struct tmp_s *)(priv->dma_tx + i);
-		seq_printf(seq, "[%d] DES0=0x%x DES1=0x%x BUF1=0x%x BUF2=0x%x",
-			   i, (unsigned int)(x->a),
-			   (unsigned int)((x->a) >> 32), x->b, x->c);
-		seq_printf(seq, "\n");
+	if (priv->extend_desc) {
+		seq_printf(seq, "Extended RX descriptor ring:\n");
+		sysfs_display_ring((void *) priv->dma_erx, rxsize, 1, seq);
+		seq_printf(seq, "Extended TX descriptor ring:\n");
+		sysfs_display_ring((void *) priv->dma_etx, txsize, 1, seq);
+	} else {
+		seq_printf(seq, "RX descriptor ring:\n");
+		sysfs_display_ring((void *)priv->dma_rx, rxsize, 0, seq);
+		seq_printf(seq, "TX descriptor ring:\n");
+		sysfs_display_ring((void *)priv->dma_tx, txsize, 0, seq);
 	}
 
 	return 0;
@@ -1895,7 +2064,7 @@ static const struct net_device_ops stmmac_netdev_ops = {
  */
 static int stmmac_hw_init(struct stmmac_priv *priv)
 {
-	int ret = 0;
+	int ret;
 	struct mac_device_info *mac;
 
 	/* Identify the MAC HW device */
@@ -1913,6 +2082,9 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
 	/* Get and dump the chip ID */
 	priv->synopsys_id = stmmac_get_synopsys_id(priv);
 
+	/* To use alternate (extended) or normal descriptor structures */
+	stmmac_selec_desc_mode(priv);
+
 	/* To use the chained or ring mode */
 	if (chain_mode)	{
 		priv->hw->chain = &chain_mode_ops;
@@ -1947,9 +2119,6 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
 	} else
 		pr_info(" No HW DMA feature register supported");
 
-	/* Select the enhnaced/normal descriptor structures */
-	stmmac_selec_desc_mode(priv);
-
 	/* Enable the IPC (Checksum Offload) and check if the feature has been
 	 * enabled during the core configuration. */
 	ret = priv->hw->mac->rx_ipc(priv->ioaddr);
@@ -1969,7 +2138,7 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
 		device_set_wakeup_capable(priv->device, 1);
 	}
 
-	return ret;
+	return 0;
 }
 
 /**
@@ -2015,7 +2184,9 @@ struct stmmac_priv *stmmac_dvr_probe(struct device *device,
 		priv->plat->phy_addr = phyaddr;
 
 	/* Init MAC and get the capabilities */
-	stmmac_hw_init(priv);
+	ret = stmmac_hw_init(priv);
+	if (ret)
+		goto error_free_netdev;
 
 	ndev->netdev_ops = &stmmac_netdev_ops;
 
@@ -2086,6 +2257,7 @@ error_clk_get:
 	unregister_netdev(ndev);
 error_netdev_register:
 	netif_napi_del(&priv->napi);
+error_free_netdev:
 	free_netdev(ndev);
 
 	return NULL;
@@ -2119,7 +2291,6 @@ int stmmac_dvr_remove(struct net_device *ndev)
 int stmmac_suspend(struct net_device *ndev)
 {
 	struct stmmac_priv *priv = netdev_priv(ndev);
-	int dis_ic = 0;
 	unsigned long flags;
 
 	if (!ndev || !netif_running(ndev))
@@ -2133,19 +2304,13 @@ int stmmac_suspend(struct net_device *ndev)
 	netif_device_detach(ndev);
 	netif_stop_queue(ndev);
 
-	if (priv->use_riwt)
-		dis_ic = 1;
-
 	napi_disable(&priv->napi);
 
 	/* Stop TX/RX DMA */
 	priv->hw->dma->stop_tx(priv->ioaddr);
 	priv->hw->dma->stop_rx(priv->ioaddr);
-	/* Clear the Rx/Tx descriptors */
-	priv->hw->desc->init_rx_desc(priv->dma_rx, priv->dma_rx_size,
-				     dis_ic, priv->mode);
-	priv->hw->desc->init_tx_desc(priv->dma_tx, priv->dma_tx_size,
-				     priv->mode);
+
+	stmmac_clear_descriptors(priv);
 
 	/* Enable Power down mode by programming the PMT regs */
 	if (device_may_wakeup(priv->device))