[openwrt/openwrt] realtek: eth: refactor transmit function
LEDE Commits
lede-commits at lists.infradead.org
Sun Feb 1 02:28:05 PST 2026
robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/41300fd88a96037fc1931b424a27618a2a4474ad
commit 41300fd88a96037fc1931b424a27618a2a4474ad
Author: Markus Stockhausen <markus.stockhausen at gmx.de>
AuthorDate: Fri Jan 30 13:58:05 2026 +0100
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 at gmx.de>
Link: https://github.com/openwrt/openwrt/pull/21778
Signed-off-by: Robert Marko <robimarko at gmail.com>
---
.../files-6.12/drivers/net/ethernet/rtl838x_eth.c | 162 +++++++++++----------
.../files-6.12/drivers/net/ethernet/rtl838x_eth.h | 2 +-
2 files changed, 84 insertions(+), 80 deletions(-)
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 f47a8c538a..b4f1b54419 100644
--- 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 bb64b88d15..cdd3b61229 100644
--- 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);
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