net: fec: fix the error to get the previous BD entry

Bug: error to get the previous BD entry. When the current BD
is the first BD, the previous BD entry must be the last BD,
not "bdp - 1" in current logic.

V4:
  * Optimize fec_enet_get_nextdesc() for code clean.
    Replace "ex_new_bd - ring_size" with "ex_base".
    Replace "new_bd - ring_size" with "base".

V3:
  * Restore the API name because David suggest to use fec_enet_
    prefix for all function in fec driver.
    So, change next_bd() -> fec_enet_get_nextdesc()
        change pre_bd()  -> fec_enet_get_prevdesc()
  * Reduce the two APIs parameters for easy to call.

V2:
  * Add tx_ring_size and rx_ring_size to struct fec_enet_private.
  * Replace api fec_enet_get_nextdesc() with next_bd().
    Replace api fec_enet_get_prevdesc() with pre_bd().

  * Move all ring size check logic to next_bd() and pre_bd(), which
    simplifies the code redundancy.

V1:
  * Add BD ring size check to get the previous BD entry in correctly.

Reviewed-by: Li Frank <B20596@freescale.com>
Signed-off-by: Fugang Duan  <B38611@freescale.com>
Acked-by: Frank Li <frank.li@freescale.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index ae23600..0120217 100644 (file)
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -296,6 +296,9 @@ struct fec_enet_private {
        /* The ring entries to be free()ed */
        struct bufdesc  *dirty_tx;
 
+       unsigned short tx_ring_size;
+       unsigned short rx_ring_size;
+
        struct  platform_device *pdev;
 
        int     opened;

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index c610a27..fd90bf5 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -239,22 +239,57 @@ MODULE_PARM_DESC(macaddr, "FEC Ethernet MAC address");
 
 static int mii_cnt;
 
-static struct bufdesc *fec_enet_get_nextdesc(struct bufdesc *bdp, int is_ex)
+static inline
+struct bufdesc *fec_enet_get_nextdesc(struct bufdesc *bdp, struct fec_enet_private *fep)
 {
-       struct bufdesc_ex *ex = (struct bufdesc_ex *)bdp;
-       if (is_ex)
-               return (struct bufdesc *)(ex + 1);
+       struct bufdesc *new_bd = bdp + 1;
+       struct bufdesc_ex *ex_new_bd = (struct bufdesc_ex *)bdp + 1;
+       struct bufdesc_ex *ex_base;
+       struct bufdesc *base;
+       int ring_size;
+
+       if (bdp >= fep->tx_bd_base) {
+               base = fep->tx_bd_base;
+               ring_size = fep->tx_ring_size;
+               ex_base = (struct bufdesc_ex *)fep->tx_bd_base;
+       } else {
+               base = fep->rx_bd_base;
+               ring_size = fep->rx_ring_size;
+               ex_base = (struct bufdesc_ex *)fep->rx_bd_base;
+       }
+
+       if (fep->bufdesc_ex)
+               return (struct bufdesc *)((ex_new_bd >= (ex_base + ring_size)) ?
+                       ex_base : ex_new_bd);
        else
-               return bdp + 1;
+               return (new_bd >= (base + ring_size)) ?
+                       base : new_bd;
 }
 
-static struct bufdesc *fec_enet_get_prevdesc(struct bufdesc *bdp, int is_ex)
+static inline
+struct bufdesc *fec_enet_get_prevdesc(struct bufdesc *bdp, struct fec_enet_private *fep)
 {
-       struct bufdesc_ex *ex = (struct bufdesc_ex *)bdp;
-       if (is_ex)
-               return (struct bufdesc *)(ex - 1);
+       struct bufdesc *new_bd = bdp - 1;
+       struct bufdesc_ex *ex_new_bd = (struct bufdesc_ex *)bdp - 1;
+       struct bufdesc_ex *ex_base;
+       struct bufdesc *base;
+       int ring_size;
+
+       if (bdp >= fep->tx_bd_base) {
+               base = fep->tx_bd_base;
+               ring_size = fep->tx_ring_size;
+               ex_base = (struct bufdesc_ex *)fep->tx_bd_base;
+       } else {
+               base = fep->rx_bd_base;
+               ring_size = fep->rx_ring_size;
+               ex_base = (struct bufdesc_ex *)fep->rx_bd_base;
+       }
+
+       if (fep->bufdesc_ex)
+               return (struct bufdesc *)((ex_new_bd < ex_base) ?
+                       (ex_new_bd + ring_size) : ex_new_bd);
        else
-               return bdp - 1;
+               return (new_bd < base) ? (new_bd + ring_size) : new_bd;
 }
 
 static void *swap_buffer(void *bufaddr, int len)
@@ -380,7 +415,7 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
                }
        }
 
-       bdp_pre = fec_enet_get_prevdesc(bdp, fep->bufdesc_ex);
+       bdp_pre = fec_enet_get_prevdesc(bdp, fep);
        if ((id_entry->driver_data & FEC_QUIRK_ERR006358) &&
            !(bdp_pre->cbd_sc & BD_ENET_TX_READY)) {
                fep->delay_work.trig_tx = true;
@@ -389,10 +424,7 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
        }
 
        /* If this was the last BD in the ring, start at the beginning again. */
-       if (status & BD_ENET_TX_WRAP)
-               bdp = fep->tx_bd_base;
-       else
-               bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+       bdp = fec_enet_get_nextdesc(bdp, fep);
 
        fep->cur_tx = bdp;
 
@@ -417,18 +449,18 @@ static void fec_enet_bd_init(struct net_device *dev)
 
        /* Initialize the receive buffer descriptors. */
        bdp = fep->rx_bd_base;
-       for (i = 0; i < RX_RING_SIZE; i++) {
+       for (i = 0; i < fep->rx_ring_size; i++) {
 
                /* Initialize the BD for every fragment in the page. */
                if (bdp->cbd_bufaddr)
                        bdp->cbd_sc = BD_ENET_RX_EMPTY;
                else
                        bdp->cbd_sc = 0;
-               bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+               bdp = fec_enet_get_nextdesc(bdp, fep);
        }
 
        /* Set the last buffer to wrap */
-       bdp = fec_enet_get_prevdesc(bdp, fep->bufdesc_ex);
+       bdp = fec_enet_get_prevdesc(bdp, fep);
        bdp->cbd_sc |= BD_SC_WRAP;
 
        fep->cur_rx = fep->rx_bd_base;
@@ -436,7 +468,7 @@ static void fec_enet_bd_init(struct net_device *dev)
        /* ...and the same for transmit */
        bdp = fep->tx_bd_base;
        fep->cur_tx = bdp;
-       for (i = 0; i < TX_RING_SIZE; i++) {
+       for (i = 0; i < fep->tx_ring_size; i++) {
 
                /* Initialize the BD for every fragment in the page. */
                bdp->cbd_sc = 0;
@@ -445,11 +477,11 @@ static void fec_enet_bd_init(struct net_device *dev)
                        fep->tx_skbuff[i] = NULL;
                }
                bdp->cbd_bufaddr = 0;
-               bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+               bdp = fec_enet_get_nextdesc(bdp, fep);
        }
 
        /* Set the last buffer to wrap */
-       bdp = fec_enet_get_prevdesc(bdp, fep->bufdesc_ex);
+       bdp = fec_enet_get_prevdesc(bdp, fep);
        bdp->cbd_sc |= BD_SC_WRAP;
        fep->dirty_tx = bdp;
 }
@@ -510,10 +542,10 @@ fec_restart(struct net_device *ndev, int duplex)
        writel(fep->bd_dma, fep->hwp + FEC_R_DES_START);
        if (fep->bufdesc_ex)
                writel((unsigned long)fep->bd_dma + sizeof(struct bufdesc_ex)
-                       * RX_RING_SIZE, fep->hwp + FEC_X_DES_START);
+                       * fep->rx_ring_size, fep->hwp + FEC_X_DES_START);
        else
                writel((unsigned long)fep->bd_dma + sizeof(struct bufdesc)
-                       * RX_RING_SIZE, fep->hwp + FEC_X_DES_START);
+                       * fep->rx_ring_size,    fep->hwp + FEC_X_DES_START);
 
 
        for (i = 0; i <= TX_RING_MOD_MASK; i++) {
@@ -727,10 +759,7 @@ fec_enet_tx(struct net_device *ndev)
        bdp = fep->dirty_tx;
 
        /* get next bdp of dirty_tx */
-       if (bdp->cbd_sc & BD_ENET_TX_WRAP)
-               bdp = fep->tx_bd_base;
-       else
-               bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+       bdp = fec_enet_get_nextdesc(bdp, fep);
 
        while (((status = bdp->cbd_sc) & BD_ENET_TX_READY) == 0) {
 
@@ -800,10 +829,7 @@ fec_enet_tx(struct net_device *ndev)
                fep->dirty_tx = bdp;
 
                /* Update pointer to next buffer descriptor to be transmitted */
-               if (status & BD_ENET_TX_WRAP)
-                       bdp = fep->tx_bd_base;
-               else
-                       bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+               bdp = fec_enet_get_nextdesc(bdp, fep);
 
                /* Since we have freed up a buffer, the ring is no longer full
                 */
@@ -993,10 +1019,8 @@ rx_processing_done:
                }
 
                /* Update BD pointer to next entry */
-               if (status & BD_ENET_RX_WRAP)
-                       bdp = fep->rx_bd_base;
-               else
-                       bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+               bdp = fec_enet_get_nextdesc(bdp, fep);
+
                /* Doing this here will keep the FEC running while we process
                 * incoming frames.  On a heavily loaded network, we should be
                 * able to keep up at the expense of system resources.
@@ -1662,7 +1686,7 @@ static void fec_enet_free_buffers(struct net_device *ndev)
        struct bufdesc  *bdp;
 
        bdp = fep->rx_bd_base;
-       for (i = 0; i < RX_RING_SIZE; i++) {
+       for (i = 0; i < fep->rx_ring_size; i++) {
                skb = fep->rx_skbuff[i];
 
                if (bdp->cbd_bufaddr)
@@ -1670,11 +1694,11 @@ static void fec_enet_free_buffers(struct net_device *ndev)
                                        FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE);
                if (skb)
                        dev_kfree_skb(skb);
-               bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+               bdp = fec_enet_get_nextdesc(bdp, fep);
        }
 
        bdp = fep->tx_bd_base;
-       for (i = 0; i < TX_RING_SIZE; i++)
+       for (i = 0; i < fep->tx_ring_size; i++)
                kfree(fep->tx_bounce[i]);
 }
 
@@ -1686,7 +1710,7 @@ static int fec_enet_alloc_buffers(struct net_device *ndev)
        struct bufdesc  *bdp;
 
        bdp = fep->rx_bd_base;
-       for (i = 0; i < RX_RING_SIZE; i++) {
+       for (i = 0; i < fep->rx_ring_size; i++) {
                skb = netdev_alloc_skb(ndev, FEC_ENET_RX_FRSIZE);
                if (!skb) {
                        fec_enet_free_buffers(ndev);
@@ -1703,15 +1727,15 @@ static int fec_enet_alloc_buffers(struct net_device *ndev)
                        ebdp->cbd_esc = BD_ENET_RX_INT;
                }
 
-               bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+               bdp = fec_enet_get_nextdesc(bdp, fep);
        }
 
        /* Set the last buffer to wrap. */
-       bdp = fec_enet_get_prevdesc(bdp, fep->bufdesc_ex);
+       bdp = fec_enet_get_prevdesc(bdp, fep);
        bdp->cbd_sc |= BD_SC_WRAP;
 
        bdp = fep->tx_bd_base;
-       for (i = 0; i < TX_RING_SIZE; i++) {
+       for (i = 0; i < fep->tx_ring_size; i++) {
                fep->tx_bounce[i] = kmalloc(FEC_ENET_TX_FRSIZE, GFP_KERNEL);
 
                bdp->cbd_sc = 0;
@@ -1722,11 +1746,11 @@ static int fec_enet_alloc_buffers(struct net_device *ndev)
                        ebdp->cbd_esc = BD_ENET_TX_INT;
                }
 
-               bdp = fec_enet_get_nextdesc(bdp, fep->bufdesc_ex);
+               bdp = fec_enet_get_nextdesc(bdp, fep);
        }
 
        /* Set the last buffer to wrap. */
-       bdp = fec_enet_get_prevdesc(bdp, fep->bufdesc_ex);
+       bdp = fec_enet_get_prevdesc(bdp, fep);
        bdp->cbd_sc |= BD_SC_WRAP;
 
        return 0;
@@ -1966,13 +1990,17 @@ static int fec_enet_init(struct net_device *ndev)
        /* Get the Ethernet address */
        fec_get_mac(ndev);
 
+       /* init the tx & rx ring size */
+       fep->tx_ring_size = TX_RING_SIZE;
+       fep->rx_ring_size = RX_RING_SIZE;
+
        /* Set receive and transmit descriptor base. */
        fep->rx_bd_base = cbd_base;
        if (fep->bufdesc_ex)
                fep->tx_bd_base = (struct bufdesc *)
-                       (((struct bufdesc_ex *)cbd_base) + RX_RING_SIZE);
+                       (((struct bufdesc_ex *)cbd_base) + fep->rx_ring_size);
        else
-               fep->tx_bd_base = cbd_base + RX_RING_SIZE;
+               fep->tx_bd_base = cbd_base + fep->rx_ring_size;
 
        /* The FEC Ethernet specific entries in the device structure */
        ndev->watchdog_timeo = TX_TIMEOUT;