Revert FEC commits

This reverts commit d5e42c86e07935f3cab4dcfca787a733146d0c70
("net: fec: Don't clear IPV6 header checksum field when IP accelerator enable").

This reverts commit 79f339125ea316e910220e5f5b4ad30370f4de85
("net: fec: Add software TSO support"), as 96c50caa5148 ("net: fec:
Enable IP header hardware checksum") causes a regression with IPv6 by
overwriting the location where the IPv4 header checksum would be:

-  0x0000:  6000 0000 0028 0640 fd8f 7570 feb6 0001 `....(.@..up....
+  0x0000:  6000 0000 0028 0640 fd8f 0000 feb6 0001 `....(.@........

This reverts commit 96c50caa5148e0e0a077672574785700885c6764
("net: fec: Enable IP header hardware checksum"), as it causes a
regression with IPv6 by overwriting the location where the IPv4
header checksum would be:

-  0x0000:  6000 0000 0028 0640 fd8f 7570 feb6 0001 `....(.@..up....
+  0x0000:  6000 0000 0028 0640 fd8f 0000 feb6 0001 `....(.@........

2 files changed, 24 insertions, 270 deletions

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 6f576a3cc204..4777242aab79 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -303,12 +303,6 @@ struct fec_enet_private {
 
 	unsigned short tx_ring_size;
 	unsigned short rx_ring_size;
-	unsigned short tx_stop_threshold;
-	unsigned short tx_wake_threshold;
-
-	/* Software TSO */
-	char *tso_hdrs;
-	dma_addr_t tso_hdrs_dma;
 
 	unsigned char flags;
 
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 7f6e5a5654fd..1ec5385e7863 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -33,13 +33,6 @@
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/skbuff.h>
-#include <linux/in.h>
-#include <linux/ip.h>
-#include <net/ip.h>
-#include <net/tso.h>
-#include <linux/tcp.h>
-#include <linux/udp.h>
-#include <linux/icmp.h>
 #include <linux/spinlock.h>
 #include <linux/workqueue.h>
 #include <linux/bitops.h>
@@ -262,15 +255,6 @@ MODULE_PARM_DESC(macaddr, "FEC Ethernet MAC address");
 #define FEC_FLAG_RX_CSUM	BIT(1)
 #define FEC_FLAG_RX_VLAN	BIT(2)
 
-#define TSO_HEADER_SIZE		128
-/* Max number of allowed TCP segments for software TSO */
-#define FEC_MAX_TSO_SEGS	100
-#define FEC_MAX_SKB_DESCS	(FEC_MAX_TSO_SEGS * 2 + MAX_SKB_FRAGS)
-
-#define IS_TSO_HEADER(txq, addr) \
-	((addr >= txq->tso_hdrs_dma) && \
-	(addr < txq->tso_hdrs_dma + txq->tx_ring_size * TSO_HEADER_SIZE))
-
 static int mii_cnt;
 
 static union bufdesc_u *
@@ -303,10 +287,10 @@ fec_enet_rx_get(unsigned int index, struct fec_enet_private *fep)
 	return bdp;
 }
 
-static unsigned int fec_enet_get_free_txdesc_num(struct fec_enet_private *fep)
+static unsigned ring_free(unsigned ins, unsigned rem, unsigned size)
 {
-	int num = fep->tx_dirty - fep->tx_next;
-	return num < 0 ? num + fep->tx_ring_size : num;
+	int num = rem - ins;
+	return num < 0 ? num + size : num;
 }
 
 static void *swap_buffer(void *bufaddr, int len)
@@ -342,11 +326,6 @@ static void fec_dump(struct net_device *ndev)
 	}
 }
 
-static inline bool is_ipv4_pkt(struct sk_buff *skb)
-{
-	return skb->protocol == htons(ETH_P_IP) && ip_hdr(skb)->version == 4;
-}
-
 static int
 fec_enet_clear_csum(struct sk_buff *skb, struct net_device *ndev)
 {
@@ -366,8 +345,6 @@ fec_enet_clear_csum(struct sk_buff *skb, struct net_device *ndev)
 	if (unlikely(skb_cow_head(skb, 0)))
 		return -1;
 
-	if (is_ipv4_pkt(skb))
-		ip_hdr(skb)->check = 0;
 	*(__sum16 *)(skb->head + skb->csum_start + skb->csum_offset) = 0;
 
 	return 0;
@@ -424,7 +401,7 @@ fec_enet_txq_submit_frag_skb(struct sk_buff *skb, struct net_device *ndev)
 
 		if (fep->flags & FEC_FLAG_BUFDESC_EX) {
 			if (skb->ip_summed == CHECKSUM_PARTIAL)
-				estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
+				estatus |= BD_ENET_TX_PINS;
 			bdp->ebd.cbd_bdu = 0;
 			bdp->ebd.cbd_esc = estatus;
 		}
@@ -485,13 +462,6 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 	unsigned int index;
 	int ret;
 
-	if (fec_enet_get_free_txdesc_num(fep) < fep->tx_min) {
-		dev_kfree_skb_any(skb);
-		if (net_ratelimit())
-			netdev_err(ndev, "NOT enough BD for SG!\n");
-		return NETDEV_TX_OK;
-	}
-
 	/* Protocol checksum off-load for TCP and UDP. */
 	if (fec_enet_clear_csum(skb, ndev)) {
 		dev_kfree_skb_any(skb);
@@ -551,7 +521,7 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 			skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
 
 		if (skb->ip_summed == CHECKSUM_PARTIAL)
-			estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
+			estatus |= BD_ENET_TX_PINS;
 
 		bdp->ebd.cbd_bdu = 0;
 		bdp->ebd.cbd_esc = estatus;
@@ -591,213 +561,27 @@ static int fec_enet_txq_submit_skb(struct sk_buff *skb, struct net_device *ndev)
 	return 0;
 }
 
-static int
-fec_enet_txq_put_data_tso(struct sk_buff *skb, struct net_device *ndev,
-			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);
-	unsigned short status;
-	unsigned int estatus = 0;
-	dma_addr_t addr;
-
-	status = bdp->bd.cbd_sc;
-	status &= ~BD_ENET_TX_STATS;
-
-	status |= (BD_ENET_TX_TC | BD_ENET_TX_READY);
-
-	if (((unsigned long) data) & FEC_ALIGNMENT ||
-		id_entry->driver_data & FEC_QUIRK_SWAP_FRAME) {
-		memcpy(fep->tx_bounce[index], data, size);
-		data = fep->tx_bounce[index];
-
-		if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
-			swap_buffer(data, size);
-	}
-
-	addr = dma_map_single(&fep->pdev->dev, data, size, DMA_TO_DEVICE);
-	if (dma_mapping_error(&fep->pdev->dev, addr)) {
-		dev_kfree_skb_any(skb);
-		if (net_ratelimit())
-			netdev_err(ndev, "Tx DMA memory map failed\n");
-		return NETDEV_TX_BUSY;
-	}
-
-	bdp->bd.cbd_datlen = size;
-	bdp->bd.cbd_bufaddr = addr;
-
-	if (fep->flags & FEC_FLAG_BUFDESC_EX) {
-		if (skb->ip_summed == CHECKSUM_PARTIAL)
-			estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
-		bdp->ebd.cbd_bdu = 0;
-		bdp->ebd.cbd_esc = estatus;
-	}
-
-	/* Handle the last BD specially */
-	if (last_tcp)
-		status |= (BD_ENET_TX_LAST | BD_ENET_TX_TC);
-	if (is_last) {
-		status |= BD_ENET_TX_INTR;
-		if (fep->flags & FEC_FLAG_BUFDESC_EX)
-			bdp->ebd.cbd_esc |= BD_ENET_TX_INT;
-	}
-
-	bdp->bd.cbd_sc = status;
-
-	return 0;
-}
-
-static int
-fec_enet_txq_put_hdr_tso(struct sk_buff *skb, struct net_device *ndev,
-			 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);
-	void *bufaddr;
-	unsigned long dmabuf;
-	unsigned short status;
-	unsigned int estatus = 0;
-
-	status = bdp->bd.cbd_sc;
-	status &= ~BD_ENET_TX_STATS;
-	status |= (BD_ENET_TX_TC | BD_ENET_TX_READY);
-
-	bufaddr = fep->tso_hdrs + index * TSO_HEADER_SIZE;
-	dmabuf = fep->tso_hdrs_dma + index * TSO_HEADER_SIZE;
-	if (((unsigned long) bufaddr) & FEC_ALIGNMENT ||
-		id_entry->driver_data & FEC_QUIRK_SWAP_FRAME) {
-		memcpy(fep->tx_bounce[index], skb->data, hdr_len);
-		bufaddr = fep->tx_bounce[index];
-
-		if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
-			swap_buffer(bufaddr, hdr_len);
-
-		dmabuf = dma_map_single(&fep->pdev->dev, bufaddr,
-					hdr_len, DMA_TO_DEVICE);
-		if (dma_mapping_error(&fep->pdev->dev, dmabuf)) {
-			dev_kfree_skb_any(skb);
-			if (net_ratelimit())
-				netdev_err(ndev, "Tx DMA memory map failed\n");
-			return NETDEV_TX_BUSY;
-		}
-	}
-
-	bdp->bd.cbd_bufaddr = dmabuf;
-	bdp->bd.cbd_datlen = hdr_len;
-
-	if (fep->flags & FEC_FLAG_BUFDESC_EX) {
-		if (skb->ip_summed == CHECKSUM_PARTIAL)
-			estatus |= BD_ENET_TX_PINS | BD_ENET_TX_IINS;
-		bdp->ebd.cbd_bdu = 0;
-		bdp->ebd.cbd_esc = estatus;
-	}
-
-	bdp->bd.cbd_sc = status;
-
-	return 0;
-}
-
-static int fec_enet_txq_submit_tso(struct sk_buff *skb, struct net_device *ndev)
+static netdev_tx_t
+fec_enet_start_xmit(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 tso_t tso;
-	unsigned int index = fep->tx_next;
-	unsigned int last_index = index;
+	int nr_frags = skb_shinfo(skb)->nr_frags;
 	int ret;
 
-	if (tso_count_descs(skb) >= fec_enet_get_free_txdesc_num(fep)) {
-		dev_kfree_skb_any(skb);
+	if (ring_free(fep->tx_next, fep->tx_dirty, fep->tx_ring_size) < 1 + nr_frags) {
+		/* Ooops.  All transmit buffers are full.  Bail out.
+		 * This should not happen, since ndev->tbusy should be set.
+		 */
 		if (net_ratelimit())
-			netdev_err(ndev, "NOT enough BD for TSO!\n");
-		return NETDEV_TX_OK;
-	}
-
-	/* Protocol checksum off-load for TCP and UDP. */
-	if (fec_enet_clear_csum(skb, ndev)) {
-		dev_kfree_skb_any(skb);
-		return NETDEV_TX_OK;
-	}
-
-	/* Initialize the TSO handler, and prepare the first payload */
-	tso_start(skb, &tso);
-
-	total_len = skb->len - hdr_len;
-	while (total_len > 0) {
-		union bufdesc_u *bdp;
-		char *hdr;
-
-		bdp = fec_enet_tx_get(index, fep);
-		data_left = min_t(int, skb_shinfo(skb)->gso_size, total_len);
-		total_len -= data_left;
-
-		/* prepare packet headers: MAC + IP + TCP */
-		hdr = fep->tso_hdrs + index * TSO_HEADER_SIZE;
-		tso_build_hdr(skb, hdr, &tso, data_left, total_len == 0);
-		ret = fec_enet_txq_put_hdr_tso(skb, ndev, bdp, index);
-		if (ret)
-			goto err_release;
-
-		while (data_left > 0) {
-			int size;
-
-			if (++index >= fep->tx_ring_size)
-				index = 0;
-
-			size = min_t(int, tso.size, data_left);
-			bdp = fec_enet_tx_get(index, fep);
-			ret = fec_enet_txq_put_data_tso(skb, ndev, bdp, index, tso.data,
-							size, size == data_left,
-							total_len == 0);
-			if (ret)
-				goto err_release;
-
-			data_left -= size;
-			tso_build_data(skb, &tso, size);
-		}
-
-		last_index = index;
-		if (++index >= fep->tx_ring_size)
-			index = 0;
+			netdev_err(ndev, "tx queue full!\n");
+		return NETDEV_TX_BUSY;
 	}
 
-	/* Save skb pointer */
-	fep->tx_skbuff[last_index] = skb;
-
-	skb_tx_timestamp(skb);
-	netdev_sent_queue(ndev, skb->len);
-	fep->tx_next = index;
-
-	/* Trigger transmission start */
-	if (readl(fep->hwp + FEC_X_DES_ACTIVE) == 0)
-		writel(0, fep->hwp + FEC_X_DES_ACTIVE);
-
-	return 0;
-
-err_release:
-	/* TODO: Release all used data descriptors for TSO */
-	return ret;
-}
-
-static netdev_tx_t
-fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
-{
-	struct fec_enet_private *fep = netdev_priv(ndev);
-	int ret;
-
-	if (skb_is_gso(skb))
-		ret = fec_enet_txq_submit_tso(skb, ndev);
-	else
-		ret = fec_enet_txq_submit_skb(skb, ndev);
+	ret = fec_enet_txq_submit_skb(skb, ndev);
 	if (ret)
 		return ret;
 
-	if (fec_enet_get_free_txdesc_num(fep) < fep->tx_stop_threshold)
+	if (ring_free(fep->tx_next, fep->tx_dirty, fep->tx_ring_size) < fep->tx_min)
 		netif_stop_queue(ndev);
 
 	return NETDEV_TX_OK;
@@ -1135,9 +919,7 @@ fec_enet_tx(struct net_device *ndev)
 
 		skb = fep->tx_skbuff[index];
 		fep->tx_skbuff[index] = NULL;
-		if (!IS_TSO_HEADER(fep, bdp->bd.cbd_bufaddr))
-			fec_enet_tx_unmap(bdp, fep);
-		bdp->bd.cbd_bufaddr = 0;
+		fec_enet_tx_unmap(bdp, fep);
 		if (!skb)
 			continue;
 
@@ -1191,7 +973,8 @@ fec_enet_tx(struct net_device *ndev)
 		writel(0, fep->hwp + FEC_X_DES_ACTIVE);
 
 	if (netif_queue_stopped(ndev) &&
-	    fec_enet_get_free_txdesc_num(fep) >= fep->tx_wake_threshold)
+	    ring_free(fep->tx_next, fep->tx_dirty, fep->tx_ring_size) >=
+	      fep->tx_min)
 		netif_wake_queue(ndev);
 }
 
@@ -2591,15 +2374,10 @@ static int fec_set_features(struct net_device *netdev,
 	}
 
 	/* Set the appropriate minimum transmit ring free threshold */
-	if (features & NETIF_F_SG) {
+	if (features & NETIF_F_SG)
 		fep->tx_min = MAX_SKB_FRAGS + 1;
-		fep->tx_stop_threshold = FEC_MAX_SKB_DESCS;
-		fep->tx_wake_threshold = (fep->tx_ring_size - fep->tx_stop_threshold) / 2;
-	} else {
+	else
 		fep->tx_min = 1;
-		fep->tx_stop_threshold = 1;
-		fep->tx_wake_threshold = 1;
-	}
 
 	/* Resume the device after updates */
 	if (netif_running(netdev) && changed & FEATURES_NEED_QUIESCE) {
@@ -2647,9 +2425,6 @@ static int fec_enet_init(struct net_device *ndev)
 	fep->tx_ring_size = TX_RING_SIZE;
 	fep->rx_ring_size = RX_RING_SIZE;
 
-	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->flags & FEC_FLAG_BUFDESC_EX)
 		bd_size *= sizeof(struct bufdesc_ex);
@@ -2661,13 +2436,6 @@ static int fec_enet_init(struct net_device *ndev)
 	if (!cbd_base)
 		return -ENOMEM;
 
-	fep->tso_hdrs = dma_alloc_coherent(NULL, fep->tx_ring_size * TSO_HEADER_SIZE,
-						&fep->tso_hdrs_dma, GFP_KERNEL);
-	if (!fep->tso_hdrs) {
-		dma_free_coherent(NULL, bd_size, cbd_base, cbd_dma);
-		return -ENOMEM;
-	}
-
 	memset(cbd_base, 0, PAGE_SIZE);
 
 	fep->netdev = ndev;
@@ -2708,25 +2476,17 @@ static int fec_enet_init(struct net_device *ndev)
 		}
 
 		if (id_entry->driver_data & FEC_QUIRK_HAS_CSUM) {
-			ndev->gso_max_segs = FEC_MAX_TSO_SEGS;
-
 			/* enable hw accelerator */
 			ndev->features |= (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM
-					| NETIF_F_RXCSUM | NETIF_F_SG |
-					NETIF_F_TSO);
+					| NETIF_F_RXCSUM | NETIF_F_SG);
 			fep->flags |= FEC_FLAG_RX_CSUM;
 		}
 	}
 
-	if (ndev->features & NETIF_F_SG) {
+	if (ndev->features & NETIF_F_SG)
 		fep->tx_min = MAX_SKB_FRAGS + 1;
-		fep->tx_stop_threshold = FEC_MAX_SKB_DESCS;
-		fep->tx_wake_threshold = (fep->tx_ring_size - fep->tx_stop_threshold) / 2;
-	} else {
+	else
 		fep->tx_min = 1;
-		fep->tx_stop_threshold = 1;
-		fep->tx_wake_threshold = 1;
-	}
 
 	ndev->hw_features = ndev->features;