ravb: RX checksum offload
Add support for RX checksum offload. This is enabled by default and
may be disabled and re-enabled using ethtool:
# ethtool -K eth0 rx off
# ethtool -K eth0 rx on
The RAVB provides a simple checksumming scheme which appears to be
completely compatible with CHECKSUM_COMPLETE: sum of all packet data after
the L2 header is appended to packet data; this may be trivially read by the
driver and used to update the skb accordingly.
In terms of performance throughput is close to gigabit line-rate both with
and without RX checksum offload enabled. Perf output, however, appears to
indicate that significantly less time is spent in do_csum(). This is as
expected.
Test results with RX checksum offload enabled:
# /usr/bin/perf_3.16 record -o /run/perf.data -a netperf -t TCP_MAERTS -H 10.4.3.162
MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.4.3.162 () port 0 AF_INET : demo
enable_enobufs failed: getprotobyname
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 10.00 937.54
Summary of output of perf report:
18.28% ksoftirqd/0 [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
10.34% ksoftirqd/0 [kernel.kallsyms] [k] __pi_memcpy
9.83% ksoftirqd/0 [kernel.kallsyms] [k] ravb_poll
7.89% ksoftirqd/0 [kernel.kallsyms] [k] skb_put
4.01% ksoftirqd/0 [kernel.kallsyms] [k] dev_gro_receive
3.37% netperf [kernel.kallsyms] [k] __arch_copy_to_user
3.17% swapper [kernel.kallsyms] [k] arch_cpu_idle
2.55% swapper [kernel.kallsyms] [k] tick_nohz_idle_enter
2.04% ksoftirqd/0 [kernel.kallsyms] [k] __pi___inval_dcache_area
2.03% swapper [kernel.kallsyms] [k] _raw_spin_unlock_irq
1.96% ksoftirqd/0 [kernel.kallsyms] [k] __netdev_alloc_skb
1.59% ksoftirqd/0 [kernel.kallsyms] [k] __slab_alloc.isra.83
Test results without RX checksum offload enabled:
# /usr/bin/perf_3.16 record -o /run/perf.data -a netperf -t TCP_MAERTS -H 10.4.3.162
MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.4.3.162 () port 0 AF_INET : demo
enable_enobufs failed: getprotobyname
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 10.00 940.20
Summary of output of perf report:
17.10% ksoftirqd/0 [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
10.99% ksoftirqd/0 [kernel.kallsyms] [k] __pi_memcpy
8.87% ksoftirqd/0 [kernel.kallsyms] [k] ravb_poll
8.16% ksoftirqd/0 [kernel.kallsyms] [k] skb_put
7.42% ksoftirqd/0 [kernel.kallsyms] [k] do_csum
3.91% ksoftirqd/0 [kernel.kallsyms] [k] dev_gro_receive
2.31% swapper [kernel.kallsyms] [k] arch_cpu_idle
2.16% ksoftirqd/0 [kernel.kallsyms] [k] __pi___inval_dcache_area
2.14% ksoftirqd/0 [kernel.kallsyms] [k] __netdev_alloc_skb
1.93% netperf [kernel.kallsyms] [k] __arch_copy_to_user
1.79% swapper [kernel.kallsyms] [k] tick_nohz_idle_enter
1.63% ksoftirqd/0 [kernel.kallsyms] [k] __slab_alloc.isra.83
Above results collected on an R-Car Gen 3 Salvator-X/r8a7796 ES1.0.
Also tested on a R-Car Gen 3 Salvator-X/r8a7795 ES1.0.
By inspection this also appears to be compatible with the ravb found
on R-Car Gen 2 SoCs, however, this patch is currently untested on such
hardware.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Simon Horman
David S. Miller
parent
acd669a8f6
commit
4d86d38186
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@ -403,8 +403,9 @@ static void ravb_emac_init(struct net_device *ndev)
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/* Receive frame limit set register */
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ravb_write(ndev, ndev->mtu + ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN, RFLR);
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/* PAUSE prohibition */
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/* EMAC Mode: PAUSE prohibition; Duplex; RX Checksum; TX; RX */
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ravb_write(ndev, ECMR_ZPF | (priv->duplex ? ECMR_DM : 0) |
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(ndev->features & NETIF_F_RXCSUM ? ECMR_RCSC : 0) |
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ECMR_TE | ECMR_RE, ECMR);
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ravb_set_rate(ndev);
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@ -520,6 +521,19 @@ static void ravb_get_tx_tstamp(struct net_device *ndev)
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}
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}
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static void ravb_rx_csum(struct sk_buff *skb)
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{
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u8 *hw_csum;
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/* The hardware checksum is 2 bytes appended to packet data */
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if (unlikely(skb->len < 2))
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return;
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hw_csum = skb_tail_pointer(skb) - 2;
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skb->csum = csum_unfold((__force __sum16)get_unaligned_le16(hw_csum));
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skb->ip_summed = CHECKSUM_COMPLETE;
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skb_trim(skb, skb->len - 2);
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}
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/* Packet receive function for Ethernet AVB */
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static bool ravb_rx(struct net_device *ndev, int *quota, int q)
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{
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@ -587,8 +601,11 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q)
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ts.tv_nsec = le32_to_cpu(desc->ts_n);
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shhwtstamps->hwtstamp = timespec64_to_ktime(ts);
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}
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skb_put(skb, pkt_len);
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skb->protocol = eth_type_trans(skb, ndev);
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if (ndev->features & NETIF_F_RXCSUM)
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ravb_rx_csum(skb);
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napi_gro_receive(&priv->napi[q], skb);
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stats->rx_packets++;
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stats->rx_bytes += pkt_len;
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@ -1842,6 +1859,38 @@ static int ravb_do_ioctl(struct net_device *ndev, struct ifreq *req, int cmd)
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return phy_mii_ioctl(phydev, req, cmd);
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}
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static void ravb_set_rx_csum(struct net_device *ndev, bool enable)
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{
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struct ravb_private *priv = netdev_priv(ndev);
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unsigned long flags;
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spin_lock_irqsave(&priv->lock, flags);
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/* Disable TX and RX */
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ravb_rcv_snd_disable(ndev);
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/* Modify RX Checksum setting */
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ravb_modify(ndev, ECMR, ECMR_RCSC, enable ? ECMR_RCSC : 0);
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/* Enable TX and RX */
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ravb_rcv_snd_enable(ndev);
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spin_unlock_irqrestore(&priv->lock, flags);
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}
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static int ravb_set_features(struct net_device *ndev,
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netdev_features_t features)
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{
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netdev_features_t changed = ndev->features ^ features;
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if (changed & NETIF_F_RXCSUM)
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ravb_set_rx_csum(ndev, features & NETIF_F_RXCSUM);
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ndev->features = features;
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return 0;
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}
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static const struct net_device_ops ravb_netdev_ops = {
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.ndo_open = ravb_open,
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.ndo_stop = ravb_close,
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@ -1853,6 +1902,7 @@ static const struct net_device_ops ravb_netdev_ops = {
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.ndo_do_ioctl = ravb_do_ioctl,
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.ndo_validate_addr = eth_validate_addr,
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.ndo_set_mac_address = eth_mac_addr,
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.ndo_set_features = ravb_set_features,
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};
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/* MDIO bus init function */
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@ -2004,6 +2054,9 @@ static int ravb_probe(struct platform_device *pdev)
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if (!ndev)
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return -ENOMEM;
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ndev->features = NETIF_F_RXCSUM;
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ndev->hw_features = NETIF_F_RXCSUM;
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pm_runtime_enable(&pdev->dev);
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pm_runtime_get_sync(&pdev->dev);
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