sh_eth: add NAPI support

The driver hasn't used NAPI so far; implement its support at last...

The patch was tested on Renesas R8A77781 BOCK-W board.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 74 insertions, 12 deletions

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index cd5987ecee4b..5233edab2dd5 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1244,7 +1244,7 @@ static int sh_eth_txfree(struct net_device *ndev)
 }
 
 /* Packet receive function */
-static int sh_eth_rx(struct net_device *ndev, u32 intr_status)
+static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
 {
         struct sh_eth_private *mdp = netdev_priv(ndev);
         struct sh_eth_rxdesc *rxdesc;
@@ -1252,6 +1252,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status)
         int entry = mdp->cur_rx % mdp->num_rx_ring;
         int boguscnt = (mdp->dirty_rx + mdp->num_rx_ring) - mdp->cur_rx;
         struct sk_buff *skb;
+        int exceeded = 0;
         u16 pkt_len = 0;
         u32 desc_status;
 
@@ -1263,6 +1264,12 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status)
                 if (--boguscnt < 0)
                         break;
 
+                if (*quota <= 0) {
+                        exceeded = 1;
+                        break;
+                }
+                (*quota)--;
+
                 if (!(desc_status & RDFEND))
                         ndev->stats.rx_length_errors++;
 
@@ -1350,7 +1357,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status)
                 sh_eth_write(ndev, EDRRR_R, EDRRR);
         }
 
-        return 0;
+        return exceeded;
 }
 
 static void sh_eth_rcv_snd_disable(struct net_device *ndev)
@@ -1491,7 +1498,7 @@ static irqreturn_t sh_eth_interrupt(int irq, void *netdev)
         struct sh_eth_private *mdp = netdev_priv(ndev);
         struct sh_eth_cpu_data *cd = mdp->cd;
         irqreturn_t ret = IRQ_NONE;
-        unsigned long intr_status;
+        unsigned long intr_status, intr_enable;
 
         spin_lock(&mdp->lock);
 
@@ -1502,25 +1509,41 @@ static irqreturn_t sh_eth_interrupt(int irq, void *netdev)
          * and we need to fully handle it in sh_eth_error() in order to quench
          * it as it doesn't get cleared by just writing 1 to the ECI bit...
          */
-        intr_status &= sh_eth_read(ndev, EESIPR) | DMAC_M_ECI;
-        /* Clear interrupt */
-        if (intr_status & (EESR_RX_CHECK | cd->tx_check | cd->eesr_err_check)) {
-                sh_eth_write(ndev, intr_status, EESR);
+        intr_enable = sh_eth_read(ndev, EESIPR);
+        intr_status &= intr_enable | DMAC_M_ECI;
+        if (intr_status & (EESR_RX_CHECK | cd->tx_check | cd->eesr_err_check))
                 ret = IRQ_HANDLED;
-        } else
+        else
                 goto other_irq;
 
-        if (intr_status & EESR_RX_CHECK)
-                sh_eth_rx(ndev, intr_status);
+        if (intr_status & EESR_RX_CHECK) {
+                if (napi_schedule_prep(&mdp->napi)) {
+                        /* Mask Rx interrupts */
+                        sh_eth_write(ndev, intr_enable & ~EESR_RX_CHECK,
+                                     EESIPR);
+                        __napi_schedule(&mdp->napi);
+                } else {
+                        dev_warn(&ndev->dev,
+                                 "ignoring interrupt, status 0x%08lx, mask 0x%08lx.\n",
+                                 intr_status, intr_enable);
+                }
+        }
 
         /* Tx Check */
         if (intr_status & cd->tx_check) {
+                /* Clear Tx interrupts */
+                sh_eth_write(ndev, intr_status & cd->tx_check, EESR);
+
                 sh_eth_txfree(ndev);
                 netif_wake_queue(ndev);
         }
 
-        if (intr_status & cd->eesr_err_check)
+        if (intr_status & cd->eesr_err_check) {
+                /* Clear error interrupts */
+                sh_eth_write(ndev, intr_status & cd->eesr_err_check, EESR);
+
                 sh_eth_error(ndev, intr_status);
+        }
 
 other_irq:
         spin_unlock(&mdp->lock);
@@ -1528,6 +1551,33 @@ other_irq:
         return ret;
 }
 
+static int sh_eth_poll(struct napi_struct *napi, int budget)
+{
+        struct sh_eth_private *mdp = container_of(napi, struct sh_eth_private,
+                                                  napi);
+        struct net_device *ndev = napi->dev;
+        int quota = budget;
+        unsigned long intr_status;
+
+        for (;;) {
+                intr_status = sh_eth_read(ndev, EESR);
+                if (!(intr_status & EESR_RX_CHECK))
+                        break;
+                /* Clear Rx interrupts */
+                sh_eth_write(ndev, intr_status & EESR_RX_CHECK, EESR);
+
+                if (sh_eth_rx(ndev, intr_status, &quota))
+                        goto out;
+        }
+
+        napi_complete(napi);
+
+        /* Reenable Rx interrupts */
+        sh_eth_write(ndev, mdp->cd->eesipr_value, EESIPR);
+out:
+        return budget - quota;
+}
+
 /* PHY state control function */
 static void sh_eth_adjust_link(struct net_device *ndev)
 {
@@ -1839,6 +1889,8 @@ static int sh_eth_open(struct net_device *ndev)
         if (ret)
                 goto out_free_irq;
 
+        napi_enable(&mdp->napi);
+
         return ret;
 
 out_free_irq:
@@ -1934,6 +1986,8 @@ static int sh_eth_close(struct net_device *ndev)
 {
         struct sh_eth_private *mdp = netdev_priv(ndev);
 
+        napi_disable(&mdp->napi);
+
         netif_stop_queue(ndev);
 
         /* Disable interrupts by clearing the interrupt mask. */
@@ -2623,10 +2677,12 @@ static int sh_eth_drv_probe(struct platform_device *pdev)
                 }
         }
 
+        netif_napi_add(ndev, &mdp->napi, sh_eth_poll, 64);
+
         /* network device register */
         ret = register_netdev(ndev);
         if (ret)
-                goto out_release;
+                goto out_napi_del;
 
         /* mdio bus init */
         ret = sh_mdio_init(ndev, pdev->id, pd);
@@ -2644,6 +2700,9 @@ static int sh_eth_drv_probe(struct platform_device *pdev)
 out_unregister:
         unregister_netdev(ndev);
 
+out_napi_del:
+        netif_napi_del(&mdp->napi);
+
 out_release:
         /* net_dev free */
         if (ndev)
@@ -2656,9 +2715,11 @@ out:
 static int sh_eth_drv_remove(struct platform_device *pdev)
 {
         struct net_device *ndev = platform_get_drvdata(pdev);
+        struct sh_eth_private *mdp = netdev_priv(ndev);
 
         sh_mdio_release(ndev);
         unregister_netdev(ndev);
+        netif_napi_del(&mdp->napi);
         pm_runtime_disable(&pdev->dev);
         free_netdev(ndev);
 
diff --git a/drivers/net/ethernet/renesas/sh_eth.h b/drivers/net/ethernet/renesas/sh_eth.h
index d05b60b826eb..029744f77af6 100644
--- a/drivers/net/ethernet/renesas/sh_eth.h
+++ b/drivers/net/ethernet/renesas/sh_eth.h
@@ -505,6 +505,7 @@ struct sh_eth_private {
         u32 cur_tx, dirty_tx;
         u32 rx_buf_sz;          /* Based on MTU+slack. */
         int edmac_endian;
+        struct napi_struct napi;
         /* MII transceiver section. */
         u32 phy_id;                                     /* PHY ID */
         struct mii_bus *mii_bus;        /* MDIO bus control */