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Message-ID: <20080710220344.GB29764@electric-eye.fr.zoreil.com>
Date: Fri, 11 Jul 2008 00:03:44 +0200
From: Francois Romieu <romieu@...zoreil.com>
To: jeff@...zik.org
Cc: netdev@...r.kernel.org,
Séguier Régis <rseguier@...eleport.net>,
akpm@...ux-foundation.org
Subject: [PATCH 1/6] 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@...zoreil.com>
Fixed-by: Séguier Régis <rseguier@...eleport.net>
---
drivers/net/via-velocity.c | 72 +++++++++++---------------------------------
drivers/net/via-velocity.h | 5 ---
2 files changed, 18 insertions(+), 59 deletions(-)
diff --git a/drivers/net/via-velocity.c b/drivers/net/via-velocity.c
index 6b8d882..117dbea 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;
@@ -1878,7 +1848,7 @@ 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
@@ -2074,9 +2044,19 @@ 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)) {
@@ -2094,23 +2074,6 @@ 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;
@@ -2202,7 +2165,8 @@ 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 7387be4..8644614 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;
--
1.5.3.3
--
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