[PATCH net-next v5 09/10] net: ethernet: mtk-star-emac: separate tx/rx handling with two NAPIs
Biao Huang
biao.huang at mediatek.com
Tue Jun 28 20:17:42 PDT 2022
Current driver may lost tx interrupts under bidirectional test with iperf3,
which leads to some unexpected issues.
This patch let rx/tx interrupt enable/disable separately, and rx/tx are
handled in different NAPIs.
Signed-off-by: Biao Huang <biao.huang at mediatek.com>
Signed-off-by: Yinghua Pan <ot_yinghua.pan at mediatek.com>
---
drivers/net/ethernet/mediatek/mtk_star_emac.c | 340 ++++++++++--------
1 file changed, 199 insertions(+), 141 deletions(-)
diff --git a/drivers/net/ethernet/mediatek/mtk_star_emac.c b/drivers/net/ethernet/mediatek/mtk_star_emac.c
index a1165f293494..87c6c9bc221d 100644
--- a/drivers/net/ethernet/mediatek/mtk_star_emac.c
+++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c
@@ -33,6 +33,7 @@
#define MTK_STAR_SKB_ALIGNMENT 16
#define MTK_STAR_HASHTABLE_MC_LIMIT 256
#define MTK_STAR_HASHTABLE_SIZE_MAX 512
+#define MTK_STAR_DESC_NEEDED (MAX_SKB_FRAGS + 4)
/* Normally we'd use NET_IP_ALIGN but on arm64 its value is 0 and it doesn't
* work for this controller.
@@ -228,7 +229,8 @@ struct mtk_star_ring_desc_data {
struct sk_buff *skb;
};
-#define MTK_STAR_RING_NUM_DESCS 128
+#define MTK_STAR_RING_NUM_DESCS 512
+#define MTK_STAR_TX_THRESH (MTK_STAR_RING_NUM_DESCS / 4)
#define MTK_STAR_NUM_TX_DESCS MTK_STAR_RING_NUM_DESCS
#define MTK_STAR_NUM_RX_DESCS MTK_STAR_RING_NUM_DESCS
#define MTK_STAR_NUM_DESCS_TOTAL (MTK_STAR_RING_NUM_DESCS * 2)
@@ -263,7 +265,8 @@ struct mtk_star_priv {
struct mtk_star_ring rx_ring;
struct mii_bus *mii;
- struct napi_struct napi;
+ struct napi_struct tx_napi;
+ struct napi_struct rx_napi;
struct device_node *phy_node;
phy_interface_t phy_intf;
@@ -379,19 +382,16 @@ mtk_star_ring_push_head_tx(struct mtk_star_ring *ring,
mtk_star_ring_push_head(ring, desc_data, flags);
}
-static unsigned int mtk_star_ring_num_used_descs(struct mtk_star_ring *ring)
+static unsigned int mtk_star_tx_ring_avail(struct mtk_star_ring *ring)
{
- return abs(ring->head - ring->tail);
-}
+ u32 avail;
-static bool mtk_star_ring_full(struct mtk_star_ring *ring)
-{
- return mtk_star_ring_num_used_descs(ring) == MTK_STAR_RING_NUM_DESCS;
-}
+ if (ring->tail > ring->head)
+ avail = ring->tail - ring->head - 1;
+ else
+ avail = MTK_STAR_RING_NUM_DESCS - ring->head + ring->tail - 1;
-static bool mtk_star_ring_descs_available(struct mtk_star_ring *ring)
-{
- return mtk_star_ring_num_used_descs(ring) > 0;
+ return avail;
}
static dma_addr_t mtk_star_dma_map_rx(struct mtk_star_priv *priv,
@@ -436,6 +436,36 @@ static void mtk_star_nic_disable_pd(struct mtk_star_priv *priv)
MTK_STAR_BIT_MAC_CFG_NIC_PD);
}
+static void mtk_star_enable_dma_irq(struct mtk_star_priv *priv,
+ bool rx, bool tx)
+{
+ u32 value;
+
+ regmap_read(priv->regs, MTK_STAR_REG_INT_MASK, &value);
+
+ if (tx)
+ value &= ~MTK_STAR_BIT_INT_STS_TNTC;
+ if (rx)
+ value &= ~MTK_STAR_BIT_INT_STS_FNRC;
+
+ regmap_write(priv->regs, MTK_STAR_REG_INT_MASK, value);
+}
+
+static void mtk_star_disable_dma_irq(struct mtk_star_priv *priv,
+ bool rx, bool tx)
+{
+ u32 value;
+
+ regmap_read(priv->regs, MTK_STAR_REG_INT_MASK, &value);
+
+ if (tx)
+ value |= MTK_STAR_BIT_INT_STS_TNTC;
+ if (rx)
+ value |= MTK_STAR_BIT_INT_STS_FNRC;
+
+ regmap_write(priv->regs, MTK_STAR_REG_INT_MASK, value);
+}
+
/* Unmask the three interrupts we care about, mask all others. */
static void mtk_star_intr_enable(struct mtk_star_priv *priv)
{
@@ -451,20 +481,11 @@ static void mtk_star_intr_disable(struct mtk_star_priv *priv)
regmap_write(priv->regs, MTK_STAR_REG_INT_MASK, ~0);
}
-static unsigned int mtk_star_intr_read(struct mtk_star_priv *priv)
-{
- unsigned int val;
-
- regmap_read(priv->regs, MTK_STAR_REG_INT_STS, &val);
-
- return val;
-}
-
static unsigned int mtk_star_intr_ack_all(struct mtk_star_priv *priv)
{
unsigned int val;
- val = mtk_star_intr_read(priv);
+ regmap_read(priv->regs, MTK_STAR_REG_INT_STS, &val);
regmap_write(priv->regs, MTK_STAR_REG_INT_STS, val);
return val;
@@ -736,25 +757,44 @@ static void mtk_star_free_tx_skbs(struct mtk_star_priv *priv)
mtk_star_ring_free_skbs(priv, ring, mtk_star_dma_unmap_tx);
}
-/* All processing for TX and RX happens in the napi poll callback.
- *
- * FIXME: The interrupt handling should be more fine-grained with each
- * interrupt enabled/disabled independently when needed. Unfortunatly this
- * turned out to impact the driver's stability and until we have something
- * working properly, we're disabling all interrupts during TX & RX processing
- * or when resetting the counter registers.
- */
+/**
+ * mtk_star_handle_irq - Interrupt Handler.
+ * @irq: interrupt number.
+ * @data: pointer to a network interface device structure.
+ * Description : this is the driver interrupt service routine.
+ * it mainly handles:
+ * 1. tx complete interrupt for frame transmission.
+ * 2. rx complete interrupt for frame reception.
+ * 3. MAC Management Counter interrupt to avoid counter overflow.
+ **/
static irqreturn_t mtk_star_handle_irq(int irq, void *data)
{
- struct mtk_star_priv *priv;
- struct net_device *ndev;
-
- ndev = data;
- priv = netdev_priv(ndev);
+ struct net_device *ndev = data;
+ struct mtk_star_priv *priv = netdev_priv(ndev);
+ unsigned int intr_status = mtk_star_intr_ack_all(priv);
+ bool rx, tx;
+
+ rx = (intr_status & MTK_STAR_BIT_INT_STS_FNRC) &&
+ napi_schedule_prep(&priv->rx_napi);
+ tx = (intr_status & MTK_STAR_BIT_INT_STS_TNTC) &&
+ napi_schedule_prep(&priv->tx_napi);
+
+ if (rx || tx) {
+ spin_lock(&priv->lock);
+ /* mask Rx and TX Complete interrupt */
+ mtk_star_disable_dma_irq(priv, rx, tx);
+ spin_unlock(&priv->lock);
+
+ if (rx)
+ __napi_schedule(&priv->rx_napi);
+ if (tx)
+ __napi_schedule(&priv->tx_napi);
+ }
- if (netif_running(ndev)) {
- mtk_star_intr_disable(priv);
- napi_schedule(&priv->napi);
+ /* interrupt is triggered once any counters reach 0x8000000 */
+ if (intr_status & MTK_STAR_REG_INT_STS_MIB_CNT_TH) {
+ mtk_star_update_stats(priv);
+ mtk_star_reset_counters(priv);
}
return IRQ_HANDLED;
@@ -970,7 +1010,8 @@ static int mtk_star_enable(struct net_device *ndev)
if (ret)
goto err_free_skbs;
- napi_enable(&priv->napi);
+ napi_enable(&priv->tx_napi);
+ napi_enable(&priv->rx_napi);
mtk_star_intr_ack_all(priv);
mtk_star_intr_enable(priv);
@@ -1003,7 +1044,8 @@ static void mtk_star_disable(struct net_device *ndev)
struct mtk_star_priv *priv = netdev_priv(ndev);
netif_stop_queue(ndev);
- napi_disable(&priv->napi);
+ napi_disable(&priv->tx_napi);
+ napi_disable(&priv->rx_napi);
mtk_star_intr_disable(priv);
mtk_star_dma_disable(priv);
mtk_star_intr_ack_all(priv);
@@ -1035,13 +1077,45 @@ static int mtk_star_netdev_ioctl(struct net_device *ndev,
return phy_mii_ioctl(ndev->phydev, req, cmd);
}
-static int mtk_star_netdev_start_xmit(struct sk_buff *skb,
- struct net_device *ndev)
+static int __mtk_star_maybe_stop_tx(struct mtk_star_priv *priv, u16 size)
+{
+ netif_stop_queue(priv->ndev);
+
+ /* Might race with mtk_star_tx_poll, check again */
+ smp_mb();
+ if (likely(mtk_star_tx_ring_avail(&priv->tx_ring) < size))
+ return -EBUSY;
+
+ netif_start_queue(priv->ndev);
+
+ return 0;
+}
+
+static inline int mtk_star_maybe_stop_tx(struct mtk_star_priv *priv, u16 size)
+{
+ if (likely(mtk_star_tx_ring_avail(&priv->tx_ring) >= size))
+ return 0;
+
+ return __mtk_star_maybe_stop_tx(priv, size);
+}
+
+static netdev_tx_t mtk_star_netdev_start_xmit(struct sk_buff *skb,
+ struct net_device *ndev)
{
struct mtk_star_priv *priv = netdev_priv(ndev);
struct mtk_star_ring *ring = &priv->tx_ring;
struct device *dev = mtk_star_get_dev(priv);
struct mtk_star_ring_desc_data desc_data;
+ int nfrags = skb_shinfo(skb)->nr_frags;
+
+ if (unlikely(mtk_star_tx_ring_avail(ring) < nfrags + 1)) {
+ if (!netif_queue_stopped(ndev)) {
+ netif_stop_queue(ndev);
+ /* This is a hard error, log it. */
+ pr_err_ratelimited("Tx ring full when queue awake\n");
+ }
+ return NETDEV_TX_BUSY;
+ }
desc_data.dma_addr = mtk_star_dma_map_tx(priv, skb);
if (dma_mapping_error(dev, desc_data.dma_addr))
@@ -1049,17 +1123,11 @@ static int mtk_star_netdev_start_xmit(struct sk_buff *skb,
desc_data.skb = skb;
desc_data.len = skb->len;
-
- spin_lock_bh(&priv->lock);
-
mtk_star_ring_push_head_tx(ring, &desc_data);
netdev_sent_queue(ndev, skb->len);
- if (mtk_star_ring_full(ring))
- netif_stop_queue(ndev);
-
- spin_unlock_bh(&priv->lock);
+ mtk_star_maybe_stop_tx(priv, MTK_STAR_DESC_NEEDED);
mtk_star_dma_resume_tx(priv);
@@ -1091,31 +1159,40 @@ static int mtk_star_tx_complete_one(struct mtk_star_priv *priv)
return ret;
}
-static void mtk_star_tx_complete_all(struct mtk_star_priv *priv)
+static int mtk_star_tx_poll(struct napi_struct *napi, int budget)
{
+ struct mtk_star_priv *priv = container_of(napi, struct mtk_star_priv,
+ tx_napi);
+ int ret = 0, pkts_compl = 0, bytes_compl = 0, count = 0;
struct mtk_star_ring *ring = &priv->tx_ring;
struct net_device *ndev = priv->ndev;
- int ret, pkts_compl, bytes_compl;
- bool wake = false;
-
- spin_lock(&priv->lock);
-
- for (pkts_compl = 0, bytes_compl = 0;;
- pkts_compl++, bytes_compl += ret, wake = true) {
- if (!mtk_star_ring_descs_available(ring))
- break;
+ unsigned int head = ring->head;
+ unsigned int entry = ring->tail;
+ while (entry != head && count < (MTK_STAR_RING_NUM_DESCS - 1)) {
ret = mtk_star_tx_complete_one(priv);
if (ret < 0)
break;
+
+ count++;
+ pkts_compl++;
+ bytes_compl += ret;
+ entry = ring->tail;
}
netdev_completed_queue(ndev, pkts_compl, bytes_compl);
- if (wake && netif_queue_stopped(ndev))
+ if (unlikely(netif_queue_stopped(ndev)) &&
+ (mtk_star_tx_ring_avail(ring) > MTK_STAR_TX_THRESH))
netif_wake_queue(ndev);
- spin_unlock(&priv->lock);
+ if (napi_complete(napi)) {
+ spin_lock(&priv->lock);
+ mtk_star_enable_dma_irq(priv, false, true);
+ spin_unlock(&priv->lock);
+ }
+
+ return 0;
}
static void mtk_star_netdev_get_stats64(struct net_device *ndev,
@@ -1195,7 +1272,7 @@ static const struct ethtool_ops mtk_star_ethtool_ops = {
.set_link_ksettings = phy_ethtool_set_link_ksettings,
};
-static int mtk_star_receive_packet(struct mtk_star_priv *priv)
+static int mtk_star_rx(struct mtk_star_priv *priv, int budget)
{
struct mtk_star_ring *ring = &priv->rx_ring;
struct device *dev = mtk_star_get_dev(priv);
@@ -1203,107 +1280,85 @@ static int mtk_star_receive_packet(struct mtk_star_priv *priv)
struct net_device *ndev = priv->ndev;
struct sk_buff *curr_skb, *new_skb;
dma_addr_t new_dma_addr;
- int ret;
+ int ret, count = 0;
- spin_lock(&priv->lock);
- ret = mtk_star_ring_pop_tail(ring, &desc_data);
- spin_unlock(&priv->lock);
- if (ret)
- return -1;
+ while (count < budget) {
+ ret = mtk_star_ring_pop_tail(ring, &desc_data);
+ if (ret)
+ return -1;
- curr_skb = desc_data.skb;
+ curr_skb = desc_data.skb;
- if ((desc_data.flags & MTK_STAR_DESC_BIT_RX_CRCE) ||
- (desc_data.flags & MTK_STAR_DESC_BIT_RX_OSIZE)) {
- /* Error packet -> drop and reuse skb. */
- new_skb = curr_skb;
- goto push_new_skb;
- }
+ if ((desc_data.flags & MTK_STAR_DESC_BIT_RX_CRCE) ||
+ (desc_data.flags & MTK_STAR_DESC_BIT_RX_OSIZE)) {
+ /* Error packet -> drop and reuse skb. */
+ new_skb = curr_skb;
+ goto push_new_skb;
+ }
- /* Prepare new skb before receiving the current one. Reuse the current
- * skb if we fail at any point.
- */
- new_skb = mtk_star_alloc_skb(ndev);
- if (!new_skb) {
- ndev->stats.rx_dropped++;
- new_skb = curr_skb;
- goto push_new_skb;
- }
+ /* Prepare new skb before receiving the current one.
+ * Reuse the current skb if we fail at any point.
+ */
+ new_skb = mtk_star_alloc_skb(ndev);
+ if (!new_skb) {
+ ndev->stats.rx_dropped++;
+ new_skb = curr_skb;
+ goto push_new_skb;
+ }
- new_dma_addr = mtk_star_dma_map_rx(priv, new_skb);
- if (dma_mapping_error(dev, new_dma_addr)) {
- ndev->stats.rx_dropped++;
- dev_kfree_skb(new_skb);
- new_skb = curr_skb;
- netdev_err(ndev, "DMA mapping error of RX descriptor\n");
- goto push_new_skb;
- }
+ new_dma_addr = mtk_star_dma_map_rx(priv, new_skb);
+ if (dma_mapping_error(dev, new_dma_addr)) {
+ ndev->stats.rx_dropped++;
+ dev_kfree_skb(new_skb);
+ new_skb = curr_skb;
+ netdev_err(ndev, "DMA mapping error of RX descriptor\n");
+ goto push_new_skb;
+ }
- /* We can't fail anymore at this point: it's safe to unmap the skb. */
- mtk_star_dma_unmap_rx(priv, &desc_data);
+ /* We can't fail anymore at this point:
+ * it's safe to unmap the skb.
+ */
+ mtk_star_dma_unmap_rx(priv, &desc_data);
- skb_put(desc_data.skb, desc_data.len);
- desc_data.skb->ip_summed = CHECKSUM_NONE;
- desc_data.skb->protocol = eth_type_trans(desc_data.skb, ndev);
- desc_data.skb->dev = ndev;
- netif_receive_skb(desc_data.skb);
+ skb_put(desc_data.skb, desc_data.len);
+ desc_data.skb->ip_summed = CHECKSUM_NONE;
+ desc_data.skb->protocol = eth_type_trans(desc_data.skb, ndev);
+ desc_data.skb->dev = ndev;
+ netif_receive_skb(desc_data.skb);
- /* update dma_addr for new skb */
- desc_data.dma_addr = new_dma_addr;
+ /* update dma_addr for new skb */
+ desc_data.dma_addr = new_dma_addr;
push_new_skb:
- desc_data.len = skb_tailroom(new_skb);
- desc_data.skb = new_skb;
- spin_lock(&priv->lock);
- mtk_star_ring_push_head_rx(ring, &desc_data);
- spin_unlock(&priv->lock);
-
- return 0;
-}
-
-static int mtk_star_process_rx(struct mtk_star_priv *priv, int budget)
-{
- int received, ret;
+ count++;
- for (received = 0, ret = 0; received < budget && ret == 0; received++)
- ret = mtk_star_receive_packet(priv);
+ desc_data.len = skb_tailroom(new_skb);
+ desc_data.skb = new_skb;
+ mtk_star_ring_push_head_rx(ring, &desc_data);
+ }
mtk_star_dma_resume_rx(priv);
- return received;
+ return count;
}
-static int mtk_star_poll(struct napi_struct *napi, int budget)
+static int mtk_star_rx_poll(struct napi_struct *napi, int budget)
{
struct mtk_star_priv *priv;
- unsigned int status;
- int received = 0;
-
- priv = container_of(napi, struct mtk_star_priv, napi);
-
- status = mtk_star_intr_read(priv);
- mtk_star_intr_ack_all(priv);
-
- if (status & MTK_STAR_BIT_INT_STS_TNTC)
- /* Clean-up all TX descriptors. */
- mtk_star_tx_complete_all(priv);
+ int work_done = 0;
- if (status & MTK_STAR_BIT_INT_STS_FNRC)
- /* Receive up to $budget packets. */
- received = mtk_star_process_rx(priv, budget);
+ priv = container_of(napi, struct mtk_star_priv, rx_napi);
- if (unlikely(status & MTK_STAR_REG_INT_STS_MIB_CNT_TH)) {
- mtk_star_update_stats(priv);
- mtk_star_reset_counters(priv);
+ work_done = mtk_star_rx(priv, budget);
+ if (work_done < budget) {
+ napi_complete_done(napi, work_done);
+ spin_lock(&priv->lock);
+ mtk_star_enable_dma_irq(priv, true, false);
+ spin_unlock(&priv->lock);
}
- if (received < budget)
- napi_complete_done(napi, received);
-
- mtk_star_intr_enable(priv);
-
- return received;
+ return work_done;
}
static void mtk_star_mdio_rwok_clear(struct mtk_star_priv *priv)
@@ -1602,7 +1657,10 @@ static int mtk_star_probe(struct platform_device *pdev)
ndev->netdev_ops = &mtk_star_netdev_ops;
ndev->ethtool_ops = &mtk_star_ethtool_ops;
- netif_napi_add(ndev, &priv->napi, mtk_star_poll, NAPI_POLL_WEIGHT);
+ netif_napi_add(ndev, &priv->rx_napi, mtk_star_rx_poll,
+ NAPI_POLL_WEIGHT);
+ netif_tx_napi_add(ndev, &priv->tx_napi, mtk_star_tx_poll,
+ NAPI_POLL_WEIGHT);
return devm_register_netdev(dev, ndev);
}
--
2.25.1
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