[PATCH v3 15/17] stmmac: do not perform zero-copy for rx frames
From: Alexandre TORGUE <hidden>
Date: 2016-02-29 13:29:03
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Giuseppe Cavallaro <redacted> This patch is to allow this driver to copy tiny frames during the reception process. This is giving more stability while stressing the driver on STi embedded systems. Signed-off-by: Giuseppe Cavallaro <redacted> Signed-off-by: Alexandre TORGUE <redacted>
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 0d01f3e..221f5cd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h@@ -74,6 +74,7 @@ struct stmmac_priv { unsigned int cur_rx; unsigned int dirty_rx; unsigned int dma_buf_sz; + unsigned int rx_copybreak; u32 rx_riwt; int hwts_rx_en; dma_addr_t *rx_skbuff_dma;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index c803d4c..3c7928e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c@@ -781,6 +781,43 @@ static int stmmac_get_ts_info(struct net_device *dev, return ethtool_op_get_ts_info(dev, info); } +static int stmmac_get_tunable(struct net_device *dev, + const struct ethtool_tunable *tuna, void *data) +{ + struct stmmac_priv *priv = netdev_priv(dev); + int ret = 0; + + switch (tuna->id) { + case ETHTOOL_RX_COPYBREAK: + *(u32 *)data = priv->rx_copybreak; + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static int stmmac_set_tunable(struct net_device *dev, + const struct ethtool_tunable *tuna, + const void *data) +{ + struct stmmac_priv *priv = netdev_priv(dev); + int ret = 0; + + switch (tuna->id) { + case ETHTOOL_RX_COPYBREAK: + priv->rx_copybreak = *(u32 *)data; + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + static const struct ethtool_ops stmmac_ethtool_ops = { .begin = stmmac_check_if_running, .get_drvinfo = stmmac_ethtool_getdrvinfo,
@@ -803,6 +840,8 @@ static const struct ethtool_ops stmmac_ethtool_ops = { .get_ts_info = stmmac_get_ts_info, .get_coalesce = stmmac_get_coalesce, .set_coalesce = stmmac_set_coalesce, + .get_tunable = stmmac_get_tunable, + .set_tunable = stmmac_set_tunable, }; void stmmac_set_ethtool_ops(struct net_device *netdev)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 3cc1355..2ffe8dd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c@@ -91,6 +91,8 @@ static int buf_sz = DEFAULT_BUFSIZE; module_param(buf_sz, int, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(buf_sz, "DMA buffer size"); +#define STMMAC_RX_COPYBREAK 256 + static const u32 default_msg_level = (NETIF_MSG_DRV | NETIF_MSG_PROBE | NETIF_MSG_LINK | NETIF_MSG_IFUP | NETIF_MSG_IFDOWN | NETIF_MSG_TIMER);
@@ -1808,6 +1810,7 @@ static int stmmac_open(struct net_device *dev) priv->xstats.threshold = tc; priv->dma_buf_sz = STMMAC_ALIGN(buf_sz); + priv->rx_copybreak = STMMAC_RX_COPYBREAK; ret = alloc_dma_desc_resources(priv); if (ret < 0) {
@@ -2159,8 +2162,7 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv) struct sk_buff *skb; skb = netdev_alloc_skb_ip_align(priv->dev, bfsize); - - if (unlikely(skb == NULL)) + if (unlikely(!skb)) break; priv->rx_skbuff[entry] = skb;
@@ -2282,23 +2284,52 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit) pr_debug("\tframe size %d, COE: %d\n", frame_len, status); } - skb = priv->rx_skbuff[entry]; - if (unlikely(!skb)) { - pr_err("%s: Inconsistent Rx descriptor chain\n", - priv->dev->name); - priv->dev->stats.rx_dropped++; - break; + + if (unlikely(frame_len < priv->rx_copybreak)) { + skb = netdev_alloc_skb_ip_align(priv->dev, + frame_len); + if (unlikely(!skb)) { + if (net_ratelimit()) + dev_warn(priv->device, + "packet dropped\n"); + priv->dev->stats.rx_dropped++; + break; + } + + dma_sync_single_for_cpu(priv->device, + priv->rx_skbuff_dma + [entry], frame_len, + DMA_FROM_DEVICE); + skb_copy_to_linear_data(skb, + priv-> + rx_skbuff[entry]->data, + frame_len); + + skb_put(skb, frame_len); + dma_sync_single_for_device(priv->device, + priv->rx_skbuff_dma + [entry], frame_len, + DMA_FROM_DEVICE); + } else { + skb = priv->rx_skbuff[entry]; + if (unlikely(!skb)) { + pr_err("%s: Inconsistent Rx chain\n", + priv->dev->name); + priv->dev->stats.rx_dropped++; + break; + } + prefetch(skb->data - NET_IP_ALIGN); + priv->rx_skbuff[entry] = NULL; + + skb_put(skb, frame_len); + dma_unmap_single(priv->device, + priv->rx_skbuff_dma[entry], + priv->dma_buf_sz, + DMA_FROM_DEVICE); } - prefetch(skb->data - NET_IP_ALIGN); - priv->rx_skbuff[entry] = NULL; stmmac_get_rx_hwtstamp(priv, entry, skb); - skb_put(skb, frame_len); - dma_unmap_single(priv->device, - priv->rx_skbuff_dma[entry], - priv->dma_buf_sz, DMA_FROM_DEVICE); - if (netif_msg_pktdata(priv)) { pr_debug("frame received (%dbytes)", frame_len); print_pkt(skb->data, frame_len);
--
1.9.1