Commit 580a6902 authored by Francois Romieu's avatar Francois Romieu Committed by Jeff Garzik
Browse files

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: default avatarFrancois Romieu <romieu@fr.zoreil.com>
Fixed-by: default avatarSéguier Régis <rseguier@e-teleport.net>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 79d16385

drivers/net/via-velocity.c

+18 −54
Original line number Diff line number Diff line
@@ -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) +

	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;

}



/**

drivers/net/via-velocity.h

+0 −5
Original line number Diff line number Diff line
@@ -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;

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