via-velocity: remove the bounce buffers

Executive summary: the bounce buffers are in my way

- they use something like a 64 * 1500 bytes area of PCI
  consistent area
- they are not resized when the MTU changes
- they are used
  - to hand-pad undersized packets. skb_pad anyone ?
  - to linearize fragmented skbs whose fragment count
    goes beyond the 7 fragments hardware limit in order
    to claim scatter-gather support

Actually the SG code is commented out and I wonder if it
could not be implemented (ab-)using the large send feature
of the chipset since the latter should support some
multi-descriptor packet transmitting.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Fixed-by: Séguier Régis <rseguier@e-teleport.net>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 18 insertions, 59 deletions

diff --git a/drivers/net/via-velocity.c b/drivers/net/via-velocity.c
index bcbf2fa9b94a..fce2dfd0e9e6 100644
--- a/drivers/net/via-velocity.c
+++ b/drivers/net/via-velocity.c
@@ -1104,7 +1104,6 @@ static int velocity_init_rings(struct velocity_info *vptr)
 {
         int i;
         unsigned int psize;
-        unsigned int tsize;
         dma_addr_t pool_dma;
         u8 *pool;
 
@@ -1133,19 +1132,6 @@ static int velocity_init_rings(struct velocity_info *vptr)
 
         vptr->rd_pool_dma = pool_dma;
 
-        tsize = vptr->options.numtx * PKT_BUF_SZ * vptr->num_txq;
-        vptr->tx_bufs = pci_alloc_consistent(vptr->pdev, tsize,
-                                                &vptr->tx_bufs_dma);
-
-        if (vptr->tx_bufs == NULL) {
-                printk(KERN_ERR "%s: DMA memory allocation failed.\n",
-                                        vptr->dev->name);
-                pci_free_consistent(vptr->pdev, psize, pool, pool_dma);
-                return -ENOMEM;
-        }
-
-        memset(vptr->tx_bufs, 0, vptr->options.numtx * PKT_BUF_SZ * vptr->num_txq);
-
         i = vptr->options.numrx * sizeof(struct rx_desc);
         pool += i;
         pool_dma += i;
@@ -1169,16 +1155,10 @@ static int velocity_init_rings(struct velocity_info *vptr)
 
 static void velocity_free_rings(struct velocity_info *vptr)
 {
-        int size;
-
-        size = vptr->options.numrx * sizeof(struct rx_desc) +
-               vptr->options.numtx * sizeof(struct tx_desc) * vptr->num_txq;
+        const int size = vptr->options.numrx * sizeof(struct rx_desc) +
+                vptr->options.numtx * sizeof(struct tx_desc) * vptr->num_txq;
 
         pci_free_consistent(vptr->pdev, size, vptr->rd_ring, vptr->rd_pool_dma);
-
-        size = vptr->options.numtx * PKT_BUF_SZ * vptr->num_txq;
-
-        pci_free_consistent(vptr->pdev, size, vptr->tx_bufs, vptr->tx_bufs_dma);
 }
 
 static inline void velocity_give_many_rx_descs(struct velocity_info *vptr)
@@ -1313,10 +1293,8 @@ static void velocity_free_rd_ring(struct velocity_info *vptr)
 
 static int velocity_init_td_ring(struct velocity_info *vptr)
 {
-        int i, j;
         dma_addr_t curr;
-        struct tx_desc *td;
-        struct velocity_td_info *td_info;
+        unsigned int j;
 
         /* Init the TD ring entries */
         for (j = 0; j < vptr->num_txq; j++) {
@@ -1331,14 +1309,6 @@ static int velocity_init_td_ring(struct velocity_info *vptr)
                         return -ENOMEM;
                 }
 
-                for (i = 0; i < vptr->options.numtx; i++, curr += sizeof(struct tx_desc)) {
-                        td = &(vptr->td_rings[j][i]);
-                        td_info = &(vptr->td_infos[j][i]);
-                        td_info->buf = vptr->tx_bufs +
-                                (j * vptr->options.numtx + i) * PKT_BUF_SZ;
-                        td_info->buf_dma = vptr->tx_bufs_dma +
-                                (j * vptr->options.numtx + i) * PKT_BUF_SZ;
-                }
                 vptr->td_tail[j] = vptr->td_curr[j] = vptr->td_used[j] = 0;
         }
         return 0;
@@ -1867,7 +1837,7 @@ static void velocity_free_tx_buf(struct velocity_info *vptr, struct velocity_td_
         /*
          *      Don't unmap the pre-allocated tx_bufs
          */
-        if (tdinfo->skb_dma && (tdinfo->skb_dma[0] != tdinfo->buf_dma)) {
+        if (tdinfo->skb_dma) {
 
                 for (i = 0; i < tdinfo->nskb_dma; i++) {
 #ifdef VELOCITY_ZERO_COPY_SUPPORT
@@ -2063,9 +2033,19 @@ static int velocity_xmit(struct sk_buff *skb, struct net_device *dev)
         struct tx_desc *td_ptr;
         struct velocity_td_info *tdinfo;
         unsigned long flags;
-        int index;
         int pktlen = skb->len;
-        __le16 len = cpu_to_le16(pktlen);
+        __le16 len;
+        int index;
+
+
+
+        if (skb->len < ETH_ZLEN) {
+                if (skb_padto(skb, ETH_ZLEN))
+                        goto out;
+                pktlen = ETH_ZLEN;
+        }
+
+        len = cpu_to_le16(pktlen);
 
 #ifdef VELOCITY_ZERO_COPY_SUPPORT
         if (skb_shinfo(skb)->nr_frags > 6 && __skb_linearize(skb)) {
@@ -2083,23 +2063,6 @@ static int velocity_xmit(struct sk_buff *skb, struct net_device *dev)
         td_ptr->tdesc1.TCR = TCR0_TIC;
         td_ptr->td_buf[0].size &= ~TD_QUEUE;
 
-        /*
-         *      Pad short frames.
-         */
-        if (pktlen < ETH_ZLEN) {
-                /* Cannot occur until ZC support */
-                pktlen = ETH_ZLEN;
-                len = cpu_to_le16(ETH_ZLEN);
-                skb_copy_from_linear_data(skb, tdinfo->buf, skb->len);
-                memset(tdinfo->buf + skb->len, 0, ETH_ZLEN - skb->len);
-                tdinfo->skb = skb;
-                tdinfo->skb_dma[0] = tdinfo->buf_dma;
-                td_ptr->tdesc0.len = len;
-                td_ptr->td_buf[0].pa_low = cpu_to_le32(tdinfo->skb_dma[0]);
-                td_ptr->td_buf[0].pa_high = 0;
-                td_ptr->td_buf[0].size = len;   /* queue is 0 anyway */
-                tdinfo->nskb_dma = 1;
-        } else
 #ifdef VELOCITY_ZERO_COPY_SUPPORT
         if (skb_shinfo(skb)->nr_frags > 0) {
                 int nfrags = skb_shinfo(skb)->nr_frags;
@@ -2191,7 +2154,8 @@ static int velocity_xmit(struct sk_buff *skb, struct net_device *dev)
         }
         dev->trans_start = jiffies;
         spin_unlock_irqrestore(&vptr->lock, flags);
-        return 0;
+out:
+        return NETDEV_TX_OK;
 }
 
 /**
diff --git a/drivers/net/via-velocity.h b/drivers/net/via-velocity.h
index 7387be4f428d..86446147284c 100644
--- a/drivers/net/via-velocity.h
+++ b/drivers/net/via-velocity.h
@@ -236,10 +236,8 @@ struct velocity_rd_info {
 
 struct velocity_td_info {
         struct sk_buff *skb;
-        u8 *buf;
         int nskb_dma;
         dma_addr_t skb_dma[7];
-        dma_addr_t buf_dma;
 };
 
 enum  velocity_owner {
@@ -1506,9 +1504,6 @@ struct velocity_info {
         dma_addr_t rd_pool_dma;
         dma_addr_t td_pool_dma[TX_QUEUE_NO];
 
-        dma_addr_t tx_bufs_dma;
-        u8 *tx_bufs;
-
         struct vlan_group    *vlgrp;
         u8 ip_addr[4];
         enum chip_type chip_id;