Skip to content

Commit

Permalink
net: fs_enet: Implement NETIF_F_SG feature
Browse files Browse the repository at this point in the history 
Freescale ethernet controllers have the capability to re-assemble fragmented
data into a single ethernet frame. This patch uses this capability and
implements NETIP_F_SG feature into the fs_enet ethernet driver.

On a MPC885, I get 53% performance improvement on a ftp transfer of a 15Mb file:
  * Without the patch : 2,8 Mbps
  * With the patch : 4,3 Mbps

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
LEROY Christophe authored and David S. Miller committed Feb 4, 2015
1 parent 2bd8248 commit 4fc9b87
Show file tree
Hide file tree
Showing 2 changed files with 66 additions and 30 deletions.
95 changes: 65 additions & 30 deletions drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -278,14 +278,20 @@ static int fs_enet_tx_napi(struct napi_struct *napi, int budget)
fep->stats.collisions++;

/* unmap */
dma_unmap_single(fep->dev, CBDR_BUFADDR(bdp),
skb->len, DMA_TO_DEVICE);
if (fep->mapped_as_page[dirtyidx])
dma_unmap_page(fep->dev, CBDR_BUFADDR(bdp),
CBDR_DATLEN(bdp), DMA_TO_DEVICE);
else
dma_unmap_single(fep->dev, CBDR_BUFADDR(bdp),
CBDR_DATLEN(bdp), DMA_TO_DEVICE);

/*
* Free the sk buffer associated with this last transmit.
*/
dev_kfree_skb(skb);
fep->tx_skbuff[dirtyidx] = NULL;
if (skb) {
dev_kfree_skb(skb);
fep->tx_skbuff[dirtyidx] = NULL;
}

/*
* Update pointer to next buffer descriptor to be transmitted.
Expand All @@ -299,7 +305,7 @@ static int fs_enet_tx_napi(struct napi_struct *napi, int budget)
* Since we have freed up a buffer, the ring is no longer
* full.
*/
if (!fep->tx_free++)
if (++fep->tx_free >= MAX_SKB_FRAGS)
do_wake = 1;
has_tx_work = 1;
}
Expand Down Expand Up @@ -509,6 +515,9 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
cbd_t __iomem *bdp;
int curidx;
u16 sc;
int nr_frags = skb_shinfo(skb)->nr_frags;
skb_frag_t *frag;
int len;

#ifdef CONFIG_FS_ENET_MPC5121_FEC
if (((unsigned long)skb->data) & 0x3) {
Expand All @@ -530,7 +539,7 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
*/
bdp = fep->cur_tx;

if (!fep->tx_free || (CBDR_SC(bdp) & BD_ENET_TX_READY)) {
if (fep->tx_free <= nr_frags || (CBDR_SC(bdp) & BD_ENET_TX_READY)) {
netif_stop_queue(dev);
spin_unlock(&fep->tx_lock);

Expand All @@ -543,35 +552,42 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
}

curidx = bdp - fep->tx_bd_base;
/*
* Clear all of the status flags.
*/
CBDC_SC(bdp, BD_ENET_TX_STATS);

/*
* Save skb pointer.
*/
fep->tx_skbuff[curidx] = skb;

fep->stats.tx_bytes += skb->len;

len = skb->len;
fep->stats.tx_bytes += len;
if (nr_frags)
len -= skb->data_len;
fep->tx_free -= nr_frags + 1;
/*
* Push the data cache so the CPM does not get stale memory data.
*/
CBDW_BUFADDR(bdp, dma_map_single(fep->dev,
skb->data, skb->len, DMA_TO_DEVICE));
CBDW_DATLEN(bdp, skb->len);
skb->data, len, DMA_TO_DEVICE));
CBDW_DATLEN(bdp, len);

fep->mapped_as_page[curidx] = 0;
frag = skb_shinfo(skb)->frags;
while (nr_frags) {
CBDC_SC(bdp,
BD_ENET_TX_STATS | BD_ENET_TX_LAST | BD_ENET_TX_TC);
CBDS_SC(bdp, BD_ENET_TX_READY);

if ((CBDR_SC(bdp) & BD_ENET_TX_WRAP) == 0)
bdp++, curidx++;
else
bdp = fep->tx_bd_base, curidx = 0;

/*
* If this was the last BD in the ring, start at the beginning again.
*/
if ((CBDR_SC(bdp) & BD_ENET_TX_WRAP) == 0)
fep->cur_tx++;
else
fep->cur_tx = fep->tx_bd_base;
len = skb_frag_size(frag);
CBDW_BUFADDR(bdp, skb_frag_dma_map(fep->dev, frag, 0, len,
DMA_TO_DEVICE));
CBDW_DATLEN(bdp, len);

if (!--fep->tx_free)
netif_stop_queue(dev);
fep->tx_skbuff[curidx] = NULL;
fep->mapped_as_page[curidx] = 1;

frag++;
nr_frags--;
}

/* Trigger transmission start */
sc = BD_ENET_TX_READY | BD_ENET_TX_INTR |
Expand All @@ -582,8 +598,22 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
* yay for hw reuse :) */
if (skb->len <= 60)
sc |= BD_ENET_TX_PAD;
CBDC_SC(bdp, BD_ENET_TX_STATS);
CBDS_SC(bdp, sc);

/* Save skb pointer. */
fep->tx_skbuff[curidx] = skb;

/* If this was the last BD in the ring, start at the beginning again. */
if ((CBDR_SC(bdp) & BD_ENET_TX_WRAP) == 0)
bdp++;
else
bdp = fep->tx_bd_base;
fep->cur_tx = bdp;

if (fep->tx_free < MAX_SKB_FRAGS)
netif_stop_queue(dev);

skb_tx_timestamp(skb);

(*fep->ops->tx_kickstart)(dev);
Expand Down Expand Up @@ -917,7 +947,7 @@ static int fs_enet_probe(struct platform_device *ofdev)
}

fpi->rx_ring = 32;
fpi->tx_ring = 32;
fpi->tx_ring = 64;
fpi->rx_copybreak = 240;
fpi->napi_weight = 17;
fpi->phy_node = of_parse_phandle(ofdev->dev.of_node, "phy-handle", 0);
Expand Down Expand Up @@ -955,7 +985,8 @@ static int fs_enet_probe(struct platform_device *ofdev)

privsize = sizeof(*fep) +
sizeof(struct sk_buff **) *
(fpi->rx_ring + fpi->tx_ring);
(fpi->rx_ring + fpi->tx_ring) +
sizeof(char) * fpi->tx_ring;

ndev = alloc_etherdev(privsize);
if (!ndev) {
Expand All @@ -978,6 +1009,8 @@ static int fs_enet_probe(struct platform_device *ofdev)

fep->rx_skbuff = (struct sk_buff **)&fep[1];
fep->tx_skbuff = fep->rx_skbuff + fpi->rx_ring;
fep->mapped_as_page = (char *)(fep->rx_skbuff + fpi->rx_ring +
fpi->tx_ring);

spin_lock_init(&fep->lock);
spin_lock_init(&fep->tx_lock);
Expand Down Expand Up @@ -1007,6 +1040,8 @@ static int fs_enet_probe(struct platform_device *ofdev)

netif_carrier_off(ndev);

ndev->features |= NETIF_F_SG;

ret = register_netdev(ndev);
if (ret)
goto out_free_bd;
Expand Down
1 change: 1 addition & 0 deletions drivers/net/ethernet/freescale/fs_enet/fs_enet.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -134,6 +134,7 @@ struct fs_enet_private {
void __iomem *ring_base;
struct sk_buff **rx_skbuff;
struct sk_buff **tx_skbuff;
char *mapped_as_page;
cbd_t __iomem *rx_bd_base; /* Address of Rx and Tx buffers. */
cbd_t __iomem *tx_bd_base;
cbd_t __iomem *dirty_tx; /* ring entries to be free()ed. */
Expand Down

0 comments on commit 4fc9b87

Please sign in to comment.