realtek: eth: refactor transmit function

Provide a new transmit function. It is cleaner and closer to
upstream than what we have now. The basic features are:

- Avoid memory moving and keep data in the SKBs
- Only protect really critcal parts by a lock as transmit
  queues will be only called once by the kernel

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/21778
Signed-off-by: Robert Marko <robimarko@gmail.com>

diff --git a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
index f47a8c538aeee00eeeed2229c24cd70aa1830878..b4f1b54419834fd8b472cefcc6ef46cc8057e9cd 100644 (file)
--- a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
+++ b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
@@ -114,7 +114,7 @@ struct notify_b {
        u32                     reserved2[8];
 };
 
-static void rteth_838x_create_tx_header(struct p_hdr *h, unsigned int dest_port, int prio)
+static void rteth_838x_create_tx_header(struct rteth_packet *h, unsigned int dest_port, int prio)
 {
        /* cpu_tag[0] is reserved on the RTL83XX SoCs */
        h->cpu_tag[1] = 0x0400;  /* BIT 10: RTL8380_CPU_TAG */
@@ -128,7 +128,7 @@ static void rteth_838x_create_tx_header(struct p_hdr *h, unsigned int dest_port,
                h->cpu_tag[2] |= ((prio & 0x7) | BIT(3)) << 12;
 }
 
-static void rteth_839x_create_tx_header(struct p_hdr *h, unsigned int dest_port, int prio)
+static void rteth_839x_create_tx_header(struct rteth_packet *h, unsigned int dest_port, int prio)
 {
        /* cpu_tag[0] is reserved on the RTL83XX SoCs */
        h->cpu_tag[1] = 0x0100; /* RTL8390_CPU_TAG marker */
@@ -149,7 +149,7 @@ static void rteth_839x_create_tx_header(struct p_hdr *h, unsigned int dest_port,
                h->cpu_tag[2] |= ((prio & 0x7) | BIT(3)) << 8;
 }
 
-static void rteth_930x_create_tx_header(struct p_hdr *h, unsigned int dest_port, int prio)
+static void rteth_930x_create_tx_header(struct rteth_packet *h, unsigned int dest_port, int prio)
 {
        h->cpu_tag[0] = 0x8000;  /* CPU tag marker */
 
@@ -168,7 +168,7 @@ static void rteth_930x_create_tx_header(struct p_hdr *h, unsigned int dest_port,
                h->cpu_tag[2] = (BIT(5) | (prio & 0x1f)) << 8;
 }
 
-static void rteth_931x_create_tx_header(struct p_hdr *h, unsigned int dest_port, int prio)
+static void rteth_931x_create_tx_header(struct rteth_packet *h, unsigned int dest_port, int prio)
 {
        h->cpu_tag[0] = 0x8000;  /* CPU tag marker */
 
@@ -557,8 +557,10 @@ static void rteth_hw_ring_setup(struct rteth_ctrl *ctrl)
        for (int i = 0; i < ctrl->rxrings; i++)
                sw_w32(KSEG1ADDR(&ring->rx_r[i]), ctrl->r->dma_rx_base + i * 4);
 
-       for (int i = 0; i < TXRINGS; i++)
-               sw_w32(KSEG1ADDR(&ring->tx_r[i]), ctrl->r->dma_tx_base + i * 4);
+       for (int r = 0; r < RTETH_TX_RINGS; r++)
+               sw_w32(ctrl->tx_dma +
+                      r * sizeof(struct rteth_tx) + offsetof(struct rteth_tx, ring),
+                      ctrl->r->dma_tx_base + r * 4);
 }
 
 static void rtl838x_hw_en_rxtx(struct rteth_ctrl *ctrl)
@@ -967,100 +969,102 @@ static void rteth_tx_timeout(struct net_device *ndev, unsigned int txqueue)
        spin_unlock_irqrestore(&ctrl->lock, flags);
 }
 
-static int rteth_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static int rteth_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
-       int len;
-       struct rteth_ctrl *ctrl = netdev_priv(dev);
-       struct ring_b *ring = ctrl->membase;
-       int ret;
-       unsigned long flags;
-       struct p_hdr *h;
-       int dest_port = -1;
-       int q = skb_get_queue_mapping(skb) % TXRINGS;
-
-       if (q) /* Check for high prio queue */
-               pr_debug("SKB priority: %d\n", skb->priority);
-
-       spin_lock_irqsave(&ctrl->lock, flags);
-       len = skb->len;
-
-       /* Check for DSA tagging at the end of the buffer */
-       if (netdev_uses_dsa(dev) &&
+       struct rteth_ctrl *ctrl = netdev_priv(netdev);
+       int slot, len = skb->len, dest_port = -1;
+       int ring = skb_get_queue_mapping(skb);
+       struct device *dev = &ctrl->pdev->dev;
+       struct rteth_packet *packet;
+       dma_addr_t packet_dma;
+
+       if (netdev_uses_dsa(netdev) &&
            skb->data[len - 4] == 0x80 &&
            skb->data[len - 3] < ctrl->r->cpu_port &&
            skb->data[len - 2] == 0x10 &&
            skb->data[len - 1] == 0x00) {
-               /* Reuse tag space for CRC if possible */
+               /* DSA tag, reuse space for CRC */
                dest_port = skb->data[len - 3];
-               skb->data[len - 4] = skb->data[len - 3] = skb->data[len - 2] = skb->data[len - 1] = 0x00;
-               len -= 4;
+               skb->data[len - 4] = skb->data[len - 3] = 0;
+               skb->data[len - 2] = skb->data[len - 1] = 0;
+       } else {
+               /* No DSA tag, add space for CRC */
+               len += 4;
        }
 
-       len += 4; /* Add space for CRC */
+       if (unlikely(skb_padto(skb, len))) {
+               netdev->stats.tx_errors++;
+               dev_warn(dev, "skb pad failed\n");
 
-       if (skb_padto(skb, len)) {
-               ret = NETDEV_TX_OK;
-               goto txdone;
+               return NETDEV_TX_OK;
        }
 
-       /* We can send this packet if CPU owns the descriptor */
-       if (!(ring->tx_r[q][ring->c_tx[q]] & 0x1)) {
-               /* Set descriptor for tx */
-               h = &ring->tx_header[q][ring->c_tx[q]];
-               h->size = len;
-               h->len = len;
-               /* On RTL8380 SoCs, small packet lengths being sent need adjustments */
-               if (ctrl->r->family_id == RTL8380_FAMILY_ID) {
-                       if (len < ETH_ZLEN - 4)
-                               h->len -= 4;
-               }
+       slot = ctrl->tx_data[ring].slot;
+       packet = &ctrl->tx_data[ring].packet[slot];
+       packet_dma = ctrl->tx_data[ring].ring[slot];
 
-               if (dest_port >= 0)
-                       ctrl->r->create_tx_header(h, dest_port, skb->priority >> 1);
+       if (unlikely(packet_dma & RTETH_OWN_CPU)) {
+               netif_stop_subqueue(netdev, ring);
+               if (net_ratelimit())
+                       dev_warn(dev, "tx ring %d busy, waiting for slot %d\n", ring, slot);
 
-               /* Copy packet data to tx buffer */
-               memcpy((void *)KSEG1ADDR(h->buf), skb->data, len);
-               /* Make sure packet data is visible to ASIC */
-               wmb();
+               return NETDEV_TX_BUSY;
+       }
 
-               /* Hand over to switch */
-               ring->tx_r[q][ring->c_tx[q]] |= 1;
+       packet->dma = dma_map_single(dev, skb->data, skb->len, DMA_TO_DEVICE);
+       if (unlikely(dma_mapping_error(dev, packet->dma))) {
+               dev_kfree_skb_any(skb);
+               netdev->stats.tx_errors++;
 
-               /* Before starting TX, prevent a Lextra bus bug on RTL8380 SoCs */
-               if (ctrl->r->family_id == RTL8380_FAMILY_ID) {
-                       for (int i = 0; i < 10; i++) {
-                               u32 val = sw_r32(ctrl->r->dma_if_ctrl);
+               return NETDEV_TX_OK;
+       }
 
-                               if ((val & 0xc) == 0xc)
-                                       break;
-                       }
-               }
+       if (likely(packet->skb)) {
+               /* cleanup old data of this slot */
+               dma_unmap_single(dev, packet->dma, packet->skb->len, DMA_TO_DEVICE);
+               dev_kfree_skb_any(packet->skb);
+       }
 
-               /* Tell switch to send data */
-               if (ctrl->r->family_id == RTL9310_FAMILY_ID || ctrl->r->family_id == RTL9300_FAMILY_ID) {
-                       /* Ring ID q == 0: Low priority, Ring ID = 1: High prio queue */
-                       if (!q)
-                               sw_w32_mask(0, BIT(2), ctrl->r->dma_if_ctrl);
-                       else
-                               sw_w32_mask(0, BIT(3), ctrl->r->dma_if_ctrl);
-               } else {
-                       sw_w32_mask(0, TX_DO, ctrl->r->dma_if_ctrl);
-               }
+       if (ctrl->r->family_id == RTL8380_FAMILY_ID) {
+               /* On RTL8380 SoCs, small packet lengths being sent need adjustments */
+               if (len < ETH_ZLEN - 4)
+                       len -= 4;
+       }
 
-               dev->stats.tx_packets++;
-               dev->stats.tx_bytes += len;
-               dev_kfree_skb(skb);
-               ring->c_tx[q] = (ring->c_tx[q] + 1) % TXRINGLEN;
-               ret = NETDEV_TX_OK;
-       } else {
-               dev_warn(&ctrl->pdev->dev, "Data is owned by switch\n");
-               ret = NETDEV_TX_BUSY;
+       if (dest_port >= 0)
+               ctrl->r->create_tx_header(packet, dest_port, 0); // TODO ok to set prio to 0?
+
+       /* Transfer data and hand packet over to switch */
+       packet->len = len;
+       packet->skb = skb;
+       dma_wmb();
+       ctrl->tx_data[ring].ring[slot] = packet_dma | RTETH_OWN_CPU;
+       ctrl->tx_data[ring].slot = (slot + 1) % RTETH_TX_RING_SIZE;
+       wmb();
+
+       spin_lock(&ctrl->tx_lock);
+
+       /* Before starting TX, prevent a Lexra bus bug on RTL8380 SoCs */
+       if (ctrl->r->family_id == RTL8380_FAMILY_ID) {
+               for (int i = 0; i < 10; i++) {
+                       u32 val = sw_r32(ctrl->r->dma_if_ctrl);
+                       if ((val & 0xc) == 0xc)
+                               break;
+               }
        }
 
-txdone:
-       spin_unlock_irqrestore(&ctrl->lock, flags);
+       /* Tell switch to send data */
+       if (ctrl->r->family_id == RTL9310_FAMILY_ID || ctrl->r->family_id == RTL9300_FAMILY_ID)
+               sw_w32_mask(0, BIT(2 + ring), ctrl->r->dma_if_ctrl);
+       else
+               sw_w32_mask(0, TX_DO, ctrl->r->dma_if_ctrl);
+
+       netdev->stats.tx_packets++;
+       netdev->stats.tx_bytes += len;
+
+       spin_unlock(&ctrl->tx_lock);
 
-       return ret;
+       return NETDEV_TX_OK;
 }
 
 static int rtl838x_hw_receive(struct net_device *dev, int r, int budget)

diff --git a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.h b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.h
index bb64b88d15b7d3a00bc7257ec6f37722e9f7c040..cdd3b612299c0cc192b650154f4ec785d76c1ce7 100644 (file)
--- a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.h
+++ b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.h
@@ -435,7 +435,7 @@ struct rteth_config {
        u32 (*get_mac_tx_pause_sts)(int port);
        int mac;
        int l2_tbl_flush_ctrl;
-       void (*create_tx_header)(struct p_hdr *h, unsigned int dest_port, int prio);
+       void (*create_tx_header)(struct rteth_packet *h, unsigned int dest_port, int prio);
        bool (*decode_tag)(struct p_hdr *h, struct dsa_tag *tag);
        void (*hw_reset)(struct rteth_ctrl *ctrl);
        int (*init_mac)(struct rteth_ctrl *ctrl);