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Message-Id: <20170410011526.4509-12-benh@kernel.crashing.org>
Date: Mon, 10 Apr 2017 11:15:25 +1000
From: Benjamin Herrenschmidt <benh@...nel.crashing.org>
To: netdev@...r.kernel.org
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: [PATCH v2 11/12] ftgmac100: Add support for fragmented tx
Add NETIF_F_SG and create multiple TX ring entries for skb fragments.
On reclaim, the skb is only freed on the segment marked as "last".
Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
--
v2. - Remove skb headlen size adjustments now that we use
eth_skb_pad().
---
drivers/net/ethernet/faraday/ftgmac100.c | 119 ++++++++++++++++++++++++-------
1 file changed, 94 insertions(+), 25 deletions(-)
diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 8a44c22..2a4d903 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -45,7 +45,7 @@
#define RX_BUF_SIZE MAX_PKT_SIZE /* must be smaller than 0x3fff */
/* Min number of tx ring entries before stopping queue */
-#define TX_THRESHOLD (1)
+#define TX_THRESHOLD (MAX_SKB_FRAGS + 1)
struct ftgmac100_descs {
struct ftgmac100_rxdes rxdes[RX_QUEUE_ENTRIES];
@@ -487,20 +487,30 @@ static void ftgmac100_txdes_set_first_segment(struct ftgmac100_txdes *txdes)
txdes->txdes0 |= cpu_to_le32(FTGMAC100_TXDES0_FTS);
}
+static inline bool ftgmac100_txdes_get_first_segment(struct ftgmac100_txdes *txdes)
+{
+ return (txdes->txdes0 & cpu_to_le32(FTGMAC100_TXDES0_FTS)) != 0;
+}
+
static void ftgmac100_txdes_set_last_segment(struct ftgmac100_txdes *txdes)
{
txdes->txdes0 |= cpu_to_le32(FTGMAC100_TXDES0_LTS);
}
+static inline bool ftgmac100_txdes_get_last_segment(struct ftgmac100_txdes *txdes)
+{
+ return (txdes->txdes0 & cpu_to_le32(FTGMAC100_TXDES0_LTS)) != 0;
+}
+
static void ftgmac100_txdes_set_buffer_size(struct ftgmac100_txdes *txdes,
unsigned int len)
{
txdes->txdes0 |= cpu_to_le32(FTGMAC100_TXDES0_TXBUF_SIZE(len));
}
-static void ftgmac100_txdes_set_txint(struct ftgmac100_txdes *txdes)
+static inline unsigned int ftgmac100_txdes_get_buffer_size(struct ftgmac100_txdes *txdes)
{
- txdes->txdes1 |= cpu_to_le32(FTGMAC100_TXDES1_TXIC);
+ return FTGMAC100_TXDES0_TXBUF_SIZE(cpu_to_le32(txdes->txdes0));
}
static void ftgmac100_txdes_set_tcpcs(struct ftgmac100_txdes *txdes)
@@ -526,7 +536,7 @@ static void ftgmac100_txdes_set_dma_addr(struct ftgmac100_txdes *txdes,
static dma_addr_t ftgmac100_txdes_get_dma_addr(struct ftgmac100_txdes *txdes)
{
- return le32_to_cpu(txdes->txdes3);
+ return (dma_addr_t)le32_to_cpu(txdes->txdes3);
}
static int ftgmac100_next_tx_pointer(int pointer)
@@ -556,13 +566,19 @@ static void ftgmac100_free_tx_packet(struct ftgmac100 *priv,
struct sk_buff *skb,
struct ftgmac100_txdes *txdes)
{
- dma_addr_t map;
+ dma_addr_t map = ftgmac100_txdes_get_dma_addr(txdes);
- map = ftgmac100_txdes_get_dma_addr(txdes);
-
- dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE);
+ if (ftgmac100_txdes_get_first_segment(txdes)) {
+ dma_unmap_single(priv->dev, map, skb_headlen(skb),
+ DMA_TO_DEVICE);
+ } else {
+ dma_unmap_page(priv->dev, map,
+ ftgmac100_txdes_get_buffer_size(txdes),
+ DMA_TO_DEVICE);
+ }
- dev_kfree_skb(skb);
+ if (ftgmac100_txdes_get_last_segment(txdes))
+ dev_kfree_skb(skb);
priv->tx_skbs[pointer] = NULL;
/* Clear txdes0 except end of ring bit, clear txdes1 as we
@@ -624,8 +640,8 @@ static int ftgmac100_hard_start_xmit(struct sk_buff *skb,
struct net_device *netdev)
{
struct ftgmac100 *priv = netdev_priv(netdev);
- struct ftgmac100_txdes *txdes;
- unsigned int pointer;
+ struct ftgmac100_txdes *txdes, *first;
+ unsigned int pointer, nfrags, len, i, j;
dma_addr_t map;
/* The HW doesn't pad small frames */
@@ -641,26 +657,33 @@ static int ftgmac100_hard_start_xmit(struct sk_buff *skb,
goto drop;
}
- map = dma_map_single(priv->dev, skb->data, skb_headlen(skb), DMA_TO_DEVICE);
- if (unlikely(dma_mapping_error(priv->dev, map))) {
- /* drop packet */
+ /* Do we have a limit on #fragments ? I yet have to get a reply
+ * from Aspeed. If there's one I haven't hit it.
+ */
+ nfrags = skb_shinfo(skb)->nr_frags;
+
+ /* Get header len */
+ len = skb_headlen(skb);
+
+ /* Map the packet head */
+ map = dma_map_single(priv->dev, skb->data, len, DMA_TO_DEVICE);
+ if (dma_mapping_error(priv->dev, map)) {
if (net_ratelimit())
- netdev_err(netdev, "map socket buffer failed\n");
+ netdev_err(netdev, "map tx packet head failed\n");
goto drop;
}
/* Grab the next free tx descriptor */
pointer = priv->tx_pointer;
- txdes = &priv->descs->txdes[pointer];
+ txdes = first = &priv->descs->txdes[pointer];
- /* setup TX descriptor */
+ /* Setup it up with the packet head. We don't set the OWN bit yet. */
priv->tx_skbs[pointer] = skb;
ftgmac100_txdes_set_dma_addr(txdes, map);
- ftgmac100_txdes_set_buffer_size(txdes, skb->len);
-
+ ftgmac100_txdes_set_buffer_size(txdes, len);
ftgmac100_txdes_set_first_segment(txdes);
- ftgmac100_txdes_set_last_segment(txdes);
- ftgmac100_txdes_set_txint(txdes);
+
+ /* Setup HW checksumming */
if (skb->ip_summed == CHECKSUM_PARTIAL) {
__be16 protocol = skb->protocol;
@@ -675,14 +698,41 @@ static int ftgmac100_hard_start_xmit(struct sk_buff *skb,
}
}
+ /* Next descriptor */
+ pointer = ftgmac100_next_tx_pointer(pointer);
+
+ /* Add the fragments */
+ for (i = 0; i < nfrags; i++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ len = frag->size;
+
+ /* Map it */
+ map = skb_frag_dma_map(priv->dev, frag, 0, len,
+ DMA_TO_DEVICE);
+ if (dma_mapping_error(priv->dev, map))
+ goto dma_err;
+
+ /* Setup descriptor */
+ priv->tx_skbs[pointer] = skb;
+ txdes = &priv->descs->txdes[pointer];
+ ftgmac100_txdes_set_dma_addr(txdes, map);
+ ftgmac100_txdes_set_buffer_size(txdes, len);
+ ftgmac100_txdes_set_dma_own(txdes);
+ pointer = ftgmac100_next_tx_pointer(pointer);
+ }
+
+ /* Tag last fragment */
+ ftgmac100_txdes_set_last_segment(txdes);
+
/* Order the previous packet and descriptor udpates
* before setting the OWN bit.
*/
dma_wmb();
- ftgmac100_txdes_set_dma_own(txdes);
+ ftgmac100_txdes_set_dma_own(first);
/* Update next TX pointer */
- priv->tx_pointer = ftgmac100_next_tx_pointer(pointer);
+ priv->tx_pointer = pointer;
/* If there isn't enough room for all the fragments of a new packet
* in the TX ring, stop the queue. The sequence below is race free
@@ -700,6 +750,25 @@ static int ftgmac100_hard_start_xmit(struct sk_buff *skb,
return NETDEV_TX_OK;
+ dma_err:
+ if (net_ratelimit())
+ netdev_err(netdev, "map tx fragment failed\n");
+
+ /* Free head */
+ pointer = priv->tx_pointer;
+ ftgmac100_free_tx_packet(priv, pointer, skb, first);
+
+ /* Then all fragments */
+ for (j = 0; j < i; j++) {
+ pointer = ftgmac100_next_tx_pointer(pointer);
+ txdes = &priv->descs->txdes[pointer];
+ ftgmac100_free_tx_packet(priv, pointer, skb, txdes);
+ }
+
+ /* This cannot be reached if we successfully mapped the
+ * last fragment, so we know ftgmac100_free_tx_packet()
+ * hasn't freed the skb yet.
+ */
drop:
/* Drop the packet */
dev_kfree_skb_any(skb);
@@ -1439,12 +1508,12 @@ static int ftgmac100_probe(struct platform_device *pdev)
* when NCSI is enabled on the interface. It doesn't work
* in that case.
*/
- netdev->features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM | NETIF_F_GRO;
+ netdev->features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM |
+ NETIF_F_GRO | NETIF_F_SG;
if (priv->use_ncsi &&
of_get_property(pdev->dev.of_node, "no-hw-checksum", NULL))
netdev->features &= ~NETIF_F_IP_CSUM;
-
/* register network device */
err = register_netdev(netdev);
if (err) {
--
2.9.3
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