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    Subject[PATCH net-next-2.6 v9 04/20] pch_can: Improve rx processing
    Date
    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>
    ---
    drivers/net/can/pch_can.c | 158 +++++++++++++++++++++++----------------------
    1 files changed, 82 insertions(+), 76 deletions(-)

    diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
    index 210957f..d646fbc 100644
    --- 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;
    --
    1.6.0.6


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