realtek: enable CRC offloading

Enables CRC calculation offloading on RTL8380/8390/9300.

Tested on Zyxel XGS1210-10 (RTL9302)/GS1900-48 (RTL8390)/GS1900-10HP (RTL8382)
On the Zyxel GS1900-10HP, an increase of 5% in iperf3 send throughput
and 11% in receive throughput is seen.

Signed-off-by: Birger Koblitz <git@birger-koblitz.de>

diff --git a/target/linux/realtek/files-5.4/drivers/net/ethernet/rtl838x_eth.c b/target/linux/realtek/files-5.4/drivers/net/ethernet/rtl838x_eth.c
index 2f678b73849077ef4ee1d18b00cb1d5ac096711c..38b2901652b1728a377f0afb3240c881d8d2d54c 100644 (file)
--- a/target/linux/realtek/files-5.4/drivers/net/ethernet/rtl838x_eth.c
+++ b/target/linux/realtek/files-5.4/drivers/net/ethernet/rtl838x_eth.c
@@ -234,19 +234,21 @@ struct dsa_tag {
        u16     port;
        u8      l2_offloaded;
        u8      prio;
+       bool    crc_error;
 };
 
 bool rtl838x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 {
        t->reason = h->cpu_tag[3] & 0xf;
-       if (t->reason != 15)
-       pr_debug("Reason: %d\n", t->reason);
        t->queue = (h->cpu_tag[0] & 0xe0) >> 5;
+       t->port = h->cpu_tag[1] & 0x1f;
+       t->crc_error = t->reason == 13;
+
+       pr_debug("Reason: %d\n", t->reason);
        if (t->reason != 4) // NIC_RX_REASON_SPECIAL_TRAP
                t->l2_offloaded = 1;
        else
                t->l2_offloaded = 0;
-       t->port = h->cpu_tag[1] & 0x1f;
 
        return t->l2_offloaded;
 }
@@ -254,37 +256,48 @@ bool rtl838x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 bool rtl839x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 {
        t->reason = h->cpu_tag[4] & 0x1f;
-       if (t->reason != 31)
+       t->queue = (h->cpu_tag[3] & 0xe000) >> 13;
+       t->port = h->cpu_tag[1] & 0x3f;
+       t->crc_error = h->cpu_tag[3] & BIT(2);
+
        pr_debug("Reason: %d\n", t->reason);
-               t->queue = (h->cpu_tag[3] & 0xe000) >> 13;
        if ((t->reason != 7) && (t->reason != 8)) // NIC_RX_REASON_RMA_USR
                t->l2_offloaded = 1;
        else
                t->l2_offloaded = 0;
-       
-       t->port = h->cpu_tag[1] & 0x3f;
 
        return t->l2_offloaded;
 }
 
-bool rtl931x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
+bool rtl930x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 {
        t->reason = h->cpu_tag[7] & 0x3f;
-       pr_debug("Reason %d\n", t->reason);
        t->queue =  (h->cpu_tag[2] >> 11) & 0x1f;
+       t->port = (h->cpu_tag[0] >> 8) & 0x1f;
+       t->crc_error = h->cpu_tag[1] & BIT(6);
+
+       pr_debug("Reason %d, port %d, queue %d\n", t->reason, t->port, t->queue);
        if (t->reason >= 19 && t->reason <= 27)
                t->l2_offloaded = 0;
        else
                t->l2_offloaded = 1;
-       t->port = (h->cpu_tag[0] >> 8) & 0x3f;
 
        return t->l2_offloaded;
 }
 
-bool rtl930x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
+bool rtl931x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 {
-       rtl931x_decode_tag(h, t);
-       t->port &= 0x1f;
+       t->reason = h->cpu_tag[7] & 0x3f;
+       t->queue =  (h->cpu_tag[2] >> 11) & 0x1f;
+       t->port = (h->cpu_tag[0] >> 8) & 0x3f;
+       t->crc_error = h->cpu_tag[1] & BIT(6);
+
+       pr_debug("Reason %d, port %d, queue %d\n", t->reason, t->port, t->queue);
+       if (t->reason >= 19 && t->reason <= 27)
+               t->l2_offloaded = 0;
+       else
+               t->l2_offloaded = 1;
+
        return t->l2_offloaded;
 }
 
@@ -731,8 +744,9 @@ static void rtl838x_hw_en_rxtx(struct rtl838x_eth_priv *priv)
         * | MEDIA_SEL
         */
        sw_w32(0x6192F, priv->r->mac_force_mode_ctrl + priv->cpu_port * 4);
-       /* allow CRC errors on CPU-port */
-       sw_w32_mask(0, 0x8, priv->r->mac_port_ctrl(priv->cpu_port));
+
+       /* Enable CRC checks on CPU-port */
+       sw_w32_mask(0, BIT(3), priv->r->mac_port_ctrl(priv->cpu_port));
 }
 
 static void rtl839x_hw_en_rxtx(struct rtl838x_eth_priv *priv)
@@ -746,8 +760,8 @@ static void rtl839x_hw_en_rxtx(struct rtl838x_eth_priv *priv)
        /* Enable DMA */
        sw_w32_mask(0, RX_EN | TX_EN, priv->r->dma_if_ctrl);
 
-       /* Restart TX/RX to CPU port */
-       sw_w32_mask(0x0, 0x3, priv->r->mac_port_ctrl(priv->cpu_port));
+       /* Restart TX/RX to CPU port, enable CRC checking */
+       sw_w32_mask(0x0, 0x3 | BIT(3), priv->r->mac_port_ctrl(priv->cpu_port));
 
        /* CPU port joins Lookup Miss Flooding Portmask */
        // TODO: The code below should also work for the RTL838x
@@ -784,8 +798,8 @@ static void rtl93xx_hw_en_rxtx(struct rtl838x_eth_priv *priv)
        /* Enable DMA */
        sw_w32_mask(0, RX_EN_93XX | TX_EN_93XX, priv->r->dma_if_ctrl);
 
-       /* Restart TX/RX to CPU port */
-       sw_w32_mask(0x0, 0x3, priv->r->mac_port_ctrl(priv->cpu_port));
+       /* Restart TX/RX to CPU port, enable CRC checking */
+       sw_w32_mask(0x0, 0x3 | BIT(4), priv->r->mac_port_ctrl(priv->cpu_port));
 
        sw_w32_mask(0, BIT(priv->cpu_port), RTL930X_L2_UNKN_UC_FLD_PMSK);
        sw_w32(0x217, priv->r->mac_force_mode_ctrl + priv->cpu_port * 4);
@@ -1115,15 +1129,20 @@ static int rtl838x_eth_tx(struct sk_buff *skb, struct net_device *dev)
        if (netdev_uses_dsa(dev) && skb->data[len-4] == 0x80 && skb->data[len-3] > 0
                        && skb->data[len-3] < 28 &&  skb->data[len-2] == 0x10
                        &&  skb->data[len-1] == 0x00) {
-               /* Reuse tag space for CRC */
+               /* Reuse tag space for CRC if possible */
                dest_port = skb->data[len-3];
                len -= 4;
        }
-       if (len < ETH_ZLEN)
-               len = ETH_ZLEN;
 
-       /* ASIC expects that packet includes CRC, so we extend by 4 bytes */
-       len += 4;
+       len += 4; // Add space for CRC
+
+       // On RTL8380 SoCs, the packet needs extra padding
+       if (priv->family_id == RTL8380_FAMILY_ID) {
+               if (len < ETH_ZLEN)
+                       len = ETH_ZLEN; // SoC not automatically padding to ETH_ZLEN
+               else
+                       len += 4;
+       }
 
        if (skb_padto(skb, len)) {
                ret = NETDEV_TX_OK;
@@ -1280,6 +1299,12 @@ static int rtl838x_hw_receive(struct net_device *dev, int r, int budget)
                                         tag.queue, len, tag.reason, tag.port);
 
                        skb->protocol = eth_type_trans(skb, dev);
+                       if (dev->features & NETIF_F_RXCSUM) {
+                               if (tag.crc_error)
+                                       skb_checksum_none_assert(skb);
+                               else
+                                       skb->ip_summed = CHECKSUM_UNNECESSARY;
+                       }
                        dev->stats.rx_packets++;
                        dev->stats.rx_bytes += len;
 
@@ -1837,6 +1862,40 @@ static int rtl838x_mdio_remove(struct rtl838x_eth_priv *priv)
        return 0;
 }
 
+static netdev_features_t rtl838x_fix_features(struct net_device *dev,
+                                         netdev_features_t features)
+{
+       return features;
+}
+
+static int rtl83xx_set_features(struct net_device *dev, netdev_features_t features)
+{
+       struct rtl838x_eth_priv *priv = netdev_priv(dev);
+
+       if ((features ^ dev->features) & NETIF_F_RXCSUM) {
+               if (!(features & NETIF_F_RXCSUM))
+                       sw_w32_mask(BIT(3), 0, priv->r->mac_port_ctrl(priv->cpu_port));
+               else
+                       sw_w32_mask(0, BIT(4), priv->r->mac_port_ctrl(priv->cpu_port));
+       }
+
+       return 0;
+}
+
+static int rtl93xx_set_features(struct net_device *dev, netdev_features_t features)
+{
+       struct rtl838x_eth_priv *priv = netdev_priv(dev);
+
+       if ((features ^ dev->features) & NETIF_F_RXCSUM) {
+               if (!(features & NETIF_F_RXCSUM))
+                       sw_w32_mask(BIT(4), 0, priv->r->mac_port_ctrl(priv->cpu_port));
+               else
+                       sw_w32_mask(0, BIT(4), priv->r->mac_port_ctrl(priv->cpu_port));
+       }
+
+       return 0;
+}
+
 static const struct net_device_ops rtl838x_eth_netdev_ops = {
        .ndo_open = rtl838x_eth_open,
        .ndo_stop = rtl838x_eth_stop,
@@ -1846,6 +1905,8 @@ static const struct net_device_ops rtl838x_eth_netdev_ops = {
        .ndo_validate_addr = eth_validate_addr,
        .ndo_set_rx_mode = rtl838x_eth_set_multicast_list,
        .ndo_tx_timeout = rtl838x_eth_tx_timeout,
+       .ndo_set_features = rtl83xx_set_features,
+       .ndo_fix_features = rtl838x_fix_features,
 };
 
 static const struct net_device_ops rtl839x_eth_netdev_ops = {
@@ -1857,6 +1918,8 @@ static const struct net_device_ops rtl839x_eth_netdev_ops = {
        .ndo_validate_addr = eth_validate_addr,
        .ndo_set_rx_mode = rtl839x_eth_set_multicast_list,
        .ndo_tx_timeout = rtl838x_eth_tx_timeout,
+       .ndo_set_features = rtl83xx_set_features,
+       .ndo_fix_features = rtl838x_fix_features,
 };
 
 static const struct net_device_ops rtl930x_eth_netdev_ops = {
@@ -1868,6 +1931,8 @@ static const struct net_device_ops rtl930x_eth_netdev_ops = {
        .ndo_validate_addr = eth_validate_addr,
        .ndo_set_rx_mode = rtl930x_eth_set_multicast_list,
        .ndo_tx_timeout = rtl838x_eth_tx_timeout,
+       .ndo_set_features = rtl93xx_set_features,
+       .ndo_fix_features = rtl838x_fix_features,
 };
 
 static const struct net_device_ops rtl931x_eth_netdev_ops = {
@@ -1879,6 +1944,8 @@ static const struct net_device_ops rtl931x_eth_netdev_ops = {
        .ndo_validate_addr = eth_validate_addr,
        .ndo_set_rx_mode = rtl931x_eth_set_multicast_list,
        .ndo_tx_timeout = rtl838x_eth_tx_timeout,
+       .ndo_set_features = rtl93xx_set_features,
+       .ndo_fix_features = rtl838x_fix_features,
 };
 
 static const struct phylink_mac_ops rtl838x_phylink_ops = {
@@ -1975,6 +2042,8 @@ static int __init rtl838x_eth_probe(struct platform_device *pdev)
        dev->ethtool_ops = &rtl838x_ethtool_ops;
        dev->min_mtu = ETH_ZLEN;
        dev->max_mtu = 1536;
+       dev->features = NETIF_F_RXCSUM | NETIF_F_HW_CSUM;
+       dev->hw_features = NETIF_F_RXCSUM;
 
        priv->id = soc_info.id;
        priv->family_id = soc_info.family;