From 4d86d38186271438ef002c5ae6e04836f01bf8bf Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Wed, 4 Oct 2017 09:54:27 +0200 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/ravb_main.c | 55 +++++++++++++++++++++++- 1 file changed, 54 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index fdf30bfa403b..a8822a756e08 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -403,8 +403,9 @@ static void ravb_emac_init(struct net_device *ndev) /* Receive frame limit set register */ ravb_write(ndev, ndev->mtu + ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN, RFLR); - /* PAUSE prohibition */ + /* EMAC Mode: PAUSE prohibition; Duplex; RX Checksum; TX; RX */ ravb_write(ndev, ECMR_ZPF | (priv->duplex ? ECMR_DM : 0) | + (ndev->features & NETIF_F_RXCSUM ? ECMR_RCSC : 0) | ECMR_TE | ECMR_RE, ECMR); ravb_set_rate(ndev); @@ -520,6 +521,19 @@ static void ravb_get_tx_tstamp(struct net_device *ndev) } } +static void ravb_rx_csum(struct sk_buff *skb) +{ + u8 *hw_csum; + + /* The hardware checksum is 2 bytes appended to packet data */ + if (unlikely(skb->len < 2)) + return; + hw_csum = skb_tail_pointer(skb) - 2; + skb->csum = csum_unfold((__force __sum16)get_unaligned_le16(hw_csum)); + skb->ip_summed = CHECKSUM_COMPLETE; + skb_trim(skb, skb->len - 2); +} + /* Packet receive function for Ethernet AVB */ static bool ravb_rx(struct net_device *ndev, int *quota, int q) { @@ -587,8 +601,11 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q) ts.tv_nsec = le32_to_cpu(desc->ts_n); shhwtstamps->hwtstamp = timespec64_to_ktime(ts); } + skb_put(skb, pkt_len); skb->protocol = eth_type_trans(skb, ndev); + if (ndev->features & NETIF_F_RXCSUM) + ravb_rx_csum(skb); napi_gro_receive(&priv->napi[q], skb); stats->rx_packets++; stats->rx_bytes += pkt_len; @@ -1842,6 +1859,38 @@ static int ravb_do_ioctl(struct net_device *ndev, struct ifreq *req, int cmd) return phy_mii_ioctl(phydev, req, cmd); } +static void ravb_set_rx_csum(struct net_device *ndev, bool enable) +{ + struct ravb_private *priv = netdev_priv(ndev); + unsigned long flags; + + spin_lock_irqsave(&priv->lock, flags); + + /* Disable TX and RX */ + ravb_rcv_snd_disable(ndev); + + /* Modify RX Checksum setting */ + ravb_modify(ndev, ECMR, ECMR_RCSC, enable ? ECMR_RCSC : 0); + + /* Enable TX and RX */ + ravb_rcv_snd_enable(ndev); + + spin_unlock_irqrestore(&priv->lock, flags); +} + +static int ravb_set_features(struct net_device *ndev, + netdev_features_t features) +{ + netdev_features_t changed = ndev->features ^ features; + + if (changed & NETIF_F_RXCSUM) + ravb_set_rx_csum(ndev, features & NETIF_F_RXCSUM); + + ndev->features = features; + + return 0; +} + static const struct net_device_ops ravb_netdev_ops = { .ndo_open = ravb_open, .ndo_stop = ravb_close, @@ -1853,6 +1902,7 @@ static const struct net_device_ops ravb_netdev_ops = { .ndo_do_ioctl = ravb_do_ioctl, .ndo_validate_addr = eth_validate_addr, .ndo_set_mac_address = eth_mac_addr, + .ndo_set_features = ravb_set_features, }; /* MDIO bus init function */ @@ -2004,6 +2054,9 @@ static int ravb_probe(struct platform_device *pdev) if (!ndev) return -ENOMEM; + ndev->features = NETIF_F_RXCSUM; + ndev->hw_features = NETIF_F_RXCSUM; + pm_runtime_enable(&pdev->dev); pm_runtime_get_sync(&pdev->dev); -- 2.30.2