pch_can: Improve rx processing

Replace complex "goto" to "do~while".
For easy to read/understand, it divides a rx function into some functions.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
index 210957f..d646fbc 100644 (file)
--- a/drivers/net/can/pch_can.c
+++ b/drivers/net/can/pch_can.c
@@ -698,83 +698,110 @@ static irqreturn_t pch_can_interrupt(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
-static int pch_can_rx_normal(struct net_device *ndev, u32 int_stat)
+static void pch_fifo_thresh(struct pch_can_priv *priv, int obj_id)
+{
+       if (obj_id < PCH_FIFO_THRESH) {
+               iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL |
+                         PCH_CMASK_ARB, &priv->regs->ifregs[0].cmask);
+
+               /* Clearing the Dir bit. */
+               pch_can_bit_clear(&priv->regs->ifregs[0].id2, PCH_ID2_DIR);
+
+               /* Clearing NewDat & IntPnd */
+               pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
+                                 PCH_IF_MCONT_INTPND);
+               pch_can_check_if_busy(&priv->regs->ifregs[0].creq, obj_id);
+       } else if (obj_id > PCH_FIFO_THRESH) {
+               pch_can_int_clr(priv, obj_id);
+       } else if (obj_id == PCH_FIFO_THRESH) {
+               int cnt;
+               for (cnt = 0; cnt < PCH_FIFO_THRESH; cnt++)
+                       pch_can_int_clr(priv, cnt + 1);
+       }
+}
+
+static void pch_can_rx_msg_lost(struct net_device *ndev, int obj_id)
+{
+       struct pch_can_priv *priv = netdev_priv(ndev);
+       struct net_device_stats *stats = &(priv->ndev->stats);
+       struct sk_buff *skb;
+       struct can_frame *cf;
+
+       netdev_dbg(priv->ndev, "Msg Obj is overwritten.\n");
+       pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
+                         PCH_IF_MCONT_MSGLOST);
+       iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL,
+                 &priv->regs->ifregs[0].cmask);
+       pch_can_check_if_busy(&priv->regs->ifregs[0].creq, obj_id);
+
+       skb = alloc_can_err_skb(ndev, &cf);
+       if (!skb)
+               return;
+
+       cf->can_id |= CAN_ERR_CRTL;
+       cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+       stats->rx_over_errors++;
+       stats->rx_errors++;
+
+       netif_receive_skb(skb);
+}
+
+static int pch_can_rx_normal(struct net_device *ndev, u32 obj_num, int quota)
 {
        u32 reg;
        canid_t id;
-       u32 ide;
-       u32 rtr;
-       int i, k;
        int rcv_pkts = 0;
        struct sk_buff *skb;
        struct can_frame *cf;
        struct pch_can_priv *priv = netdev_priv(ndev);
        struct net_device_stats *stats = &(priv->ndev->stats);
+       int i;
+       u32 id2;
        u16 data_reg;
 
-       /* Reading the messsage object from the Message RAM */
-       iowrite32(PCH_CMASK_RX_TX_GET, &priv->regs->ifregs[0].cmask);
-       pch_can_check_if_busy(&priv->regs->ifregs[0].creq, int_stat);
+       do {
+               /* Reading the messsage object from the Message RAM */
+               iowrite32(PCH_CMASK_RX_TX_GET, &priv->regs->ifregs[0].cmask);
+               pch_can_check_if_busy(&priv->regs->ifregs[0].creq, obj_num);
 
-       /* Reading the MCONT register. */
-       reg = ioread32(&priv->regs->ifregs[0].mcont);
-       reg &= 0xffff;
+               /* Reading the MCONT register. */
+               reg = ioread32(&priv->regs->ifregs[0].mcont);
+
+               if (reg & PCH_IF_MCONT_EOB)
+                       break;
 
-       for (k = int_stat; !(reg & PCH_IF_MCONT_EOB); k++) {
                /* If MsgLost bit set. */
                if (reg & PCH_IF_MCONT_MSGLOST) {
-                       dev_err(&priv->ndev->dev, "Msg Obj is overwritten.\n");
-                       pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
-                                         PCH_IF_MCONT_MSGLOST);
-                       iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL,
-                                 &priv->regs->ifregs[0].cmask);
-                       pch_can_check_if_busy(&priv->regs->ifregs[0].creq, k);
-
-                       skb = alloc_can_err_skb(ndev, &cf);
-                       if (!skb)
-                               return -ENOMEM;
-
-                       priv->can.can_stats.error_passive++;
-                       priv->can.state = CAN_STATE_ERROR_PASSIVE;
-                       cf->can_id |= CAN_ERR_CRTL;
-                       cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
-                       cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
-                       stats->rx_packets++;
-                       stats->rx_bytes += cf->can_dlc;
-
-                       netif_receive_skb(skb);
+                       pch_can_rx_msg_lost(ndev, obj_num);
                        rcv_pkts++;
-                       goto RX_NEXT;
+                       quota--;
+                       obj_num++;
+                       continue;
+               } else if (!(reg & PCH_IF_MCONT_NEWDAT)) {
+                       obj_num++;
+                       continue;
                }
-               if (!(reg & PCH_IF_MCONT_NEWDAT))
-                       goto RX_NEXT;
 
                skb = alloc_can_skb(priv->ndev, &cf);
                if (!skb)
                        return -ENOMEM;
 
                /* Get Received data */
-               ide = ((ioread32(&priv->regs->ifregs[0].id2)) & PCH_ID2_XTD) >>
-                                                                            14;
-               if (ide) {
+               id2 = ioread32(&priv->regs->ifregs[0].id2);
+               if (id2 & PCH_ID2_XTD) {
                        id = (ioread32(&priv->regs->ifregs[0].id1) & 0xffff);
-                       id |= (((ioread32(&priv->regs->ifregs[0].id2)) &
-                                           0x1fff) << 16);
-                       cf->can_id = (id & CAN_EFF_MASK) | CAN_EFF_FLAG;
+                       id |= (((id2) & 0x1fff) << 16);
+                       cf->can_id = id | CAN_EFF_FLAG;
                } else {
-                       id = (((ioread32(&priv->regs->ifregs[0].id2)) &
-                                                    (CAN_SFF_MASK << 2)) >> 2);
-                       cf->can_id = (id & CAN_SFF_MASK);
+                       id = (id2 >> 2) & CAN_SFF_MASK;
+                       cf->can_id = id;
                }
 
-               rtr = (ioread32(&priv->regs->ifregs[0].id2) &  PCH_ID2_DIR);
-               if (rtr) {
-                       cf->can_dlc = 0;
+               if (id2 & PCH_ID2_DIR)
                        cf->can_id |= CAN_RTR_FLAG;
-               } else {
-                       cf->can_dlc =
-                             ((ioread32(&priv->regs->ifregs[0].mcont)) & 0x0f);
-               }
+
+               cf->can_dlc = get_can_dlc((ioread32(&priv->regs->
+                                                   ifregs[0].mcont)) & 0xF);
 
                for (i = 0; i < cf->can_dlc; i += 2) {
                        data_reg = ioread16(&priv->regs->ifregs[0].data[i / 2]);
@@ -785,33 +812,12 @@ static int pch_can_rx_normal(struct net_device *ndev, u32 int_stat)
                netif_receive_skb(skb);
                rcv_pkts++;
                stats->rx_packets++;
+               quota--;
                stats->rx_bytes += cf->can_dlc;
 
-               if (k < PCH_FIFO_THRESH) {
-                       iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL |
-                                 PCH_CMASK_ARB, &priv->regs->ifregs[0].cmask);
-
-                       /* Clearing the Dir bit. */
-                       pch_can_bit_clear(&priv->regs->ifregs[0].id2,
-                                         PCH_ID2_DIR);
-
-                       /* Clearing NewDat & IntPnd */
-                       pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
-                                         PCH_IF_MCONT_INTPND);
-                       pch_can_check_if_busy(&priv->regs->ifregs[0].creq, k);
-               } else if (k > PCH_FIFO_THRESH) {
-                       pch_can_int_clr(priv, k);
-               } else if (k == PCH_FIFO_THRESH) {
-                       int cnt;
-                       for (cnt = 0; cnt < PCH_FIFO_THRESH; cnt++)
-                               pch_can_int_clr(priv, cnt+1);
-               }
-RX_NEXT:
-               /* Reading the messsage object from the Message RAM */
-               iowrite32(PCH_CMASK_RX_TX_GET, &priv->regs->ifregs[0].cmask);
-               pch_can_check_if_busy(&priv->regs->ifregs[0].creq, k);
-               reg = ioread32(&priv->regs->ifregs[0].mcont);
-       }
+               pch_fifo_thresh(priv, obj_num);
+               obj_num++;
+       } while (quota > 0);
 
        return rcv_pkts;
 }
@@ -869,7 +875,7 @@ static int pch_can_rx_poll(struct napi_struct *napi, int quota)
                goto end;
 
        if ((int_stat >= PCH_RX_OBJ_START) && (int_stat <= PCH_RX_OBJ_END)) {
-               rcv_pkts += pch_can_rx_normal(ndev, int_stat);
+               rcv_pkts += pch_can_rx_normal(ndev, int_stat, quota);
                quota -= rcv_pkts;
                if (quota < 0)
                        goto end;