korina: fix handling tx_chain_tail

Originally this must have been a rewrite error when introducing
'chain_index'. But the original driver did not use the previous chain
item everywhere: when altering the address tx_chain_tail points to, it
should move forward, not backwards.
Also this is not an "index" but rather the penultimate element in the
chain, so rename it accordingly.

Signed-off-by: Phil Sutter <n0-1@freewrt.org>
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/korina.c b/drivers/net/korina.c
index dced5e7..f200175 100644 (file)
--- a/drivers/net/korina.c
+++ b/drivers/net/korina.c
@@ -199,7 +199,7 @@ static int korina_send_packet(struct sk_buff *skb, struct net_device *dev)
        struct korina_private *lp = netdev_priv(dev);
        unsigned long flags;
        u32 length;
-       u32 chain_index;
+       u32 chain_prev, chain_next;
        struct dma_desc *td;
 
        spin_lock_irqsave(&lp->lock, flags);
@@ -231,8 +231,8 @@ static int korina_send_packet(struct sk_buff *skb, struct net_device *dev)
        /* Setup the transmit descriptor. */
        dma_cache_inv((u32) td, sizeof(*td));
        td->ca = CPHYSADDR(skb->data);
-       chain_index = (lp->tx_chain_tail - 1) &
-                       KORINA_TDS_MASK;
+       chain_prev = (lp->tx_chain_tail - 1) & KORINA_TDS_MASK;
+       chain_next = (lp->tx_chain_tail + 1) & KORINA_TDS_MASK;
 
        if (readl(&(lp->tx_dma_regs->dmandptr)) == 0) {
                if (lp->tx_chain_status == desc_empty) {
@@ -240,7 +240,7 @@ static int korina_send_packet(struct sk_buff *skb, struct net_device *dev)
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
                        /* Move tail */
-                       lp->tx_chain_tail = chain_index;
+                       lp->tx_chain_tail = chain_next;
                        /* Write to NDPTR */
                        writel(CPHYSADDR(&lp->td_ring[lp->tx_chain_head]),
                                        &lp->tx_dma_regs->dmandptr);
@@ -251,12 +251,12 @@ static int korina_send_packet(struct sk_buff *skb, struct net_device *dev)
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
                        /* Link to prev */
-                       lp->td_ring[chain_index].control &=
+                       lp->td_ring[chain_prev].control &=
                                        ~DMA_DESC_COF;
                        /* Link to prev */
-                       lp->td_ring[chain_index].link =  CPHYSADDR(td);
+                       lp->td_ring[chain_prev].link =  CPHYSADDR(td);
                        /* Move tail */
-                       lp->tx_chain_tail = chain_index;
+                       lp->tx_chain_tail = chain_next;
                        /* Write to NDPTR */
                        writel(CPHYSADDR(&lp->td_ring[lp->tx_chain_head]),
                                        &(lp->tx_dma_regs->dmandptr));
@@ -270,17 +270,17 @@ static int korina_send_packet(struct sk_buff *skb, struct net_device *dev)
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
                        /* Move tail */
-                       lp->tx_chain_tail = chain_index;
+                       lp->tx_chain_tail = chain_next;
                        lp->tx_chain_status = desc_filled;
                        netif_stop_queue(dev);
                } else {
                        /* Update tail */
                        td->control = DMA_COUNT(length) |
                                        DMA_DESC_COF | DMA_DESC_IOF;
-                       lp->td_ring[chain_index].control &=
+                       lp->td_ring[chain_prev].control &=
                                        ~DMA_DESC_COF;
-                       lp->td_ring[chain_index].link =  CPHYSADDR(td);
-                       lp->tx_chain_tail = chain_index;
+                       lp->td_ring[chain_prev].link =  CPHYSADDR(td);
+                       lp->tx_chain_tail = chain_next;
                }
        }
        dma_cache_wback((u32) td, sizeof(*td));