[PATCH 5.15 20/55] net: ethernet: mtk-star-emac: separate tx/rx handling with two NAPIs

5.15-stable review patch. If anyone has any objections, please let me know.

------------------

From: Biao Huang biao.huang@mediatek.com

[ Upstream commit 0a8bd81fd6aaace14979152e0540da8ff158a00a ]

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@mediatek.com Signed-off-by: Yinghua Pan ot_yinghua.pan@mediatek.com Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: e54b4db35e20 ("net: ethernet: mtk-star-emac: rearm interrupts in rx_poll only when advised") Signed-off-by: Sasha Levin sashal@kernel.org --- 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 392648246d8f4..209e79f2c3e8c 100644 --- a/drivers/net/ethernet/mediatek/mtk_star_emac.c +++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c @@ -32,6 +32,7 @@ #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. @@ -216,7 +217,8 @@ 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) @@ -246,7 +248,8 @@ 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; @@ -357,19 +360,16 @@ 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, @@ -414,6 +414,36 @@ 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) { @@ -429,20 +459,11 @@ 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; @@ -714,25 +735,44 @@ 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; @@ -955,7 +995,8 @@ 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); @@ -988,7 +1029,8 @@ 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); @@ -1020,13 +1062,45 @@ 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)) @@ -1034,17 +1108,11 @@ 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);

@@ -1076,31 +1144,40 @@ 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, @@ -1180,7 +1257,7 @@ 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); @@ -1188,107 +1265,85 @@ 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) @@ -1551,7 +1606,10 @@ 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);

phydev = of_phy_find_device(priv->phy_node); if (phydev) {