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git://projects.qi-hardware.com/openwrt-xburst.git
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62 lines
1.9 KiB
Diff
62 lines
1.9 KiB
Diff
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From 544631281bed5cc37b8f2d3a99f44c9d4b97f9a8 Mon Sep 17 00:00:00 2001
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From: Daniel Hellstrom <daniel@gaisler.com>
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Date: Wed, 1 Dec 2010 10:07:12 +0100
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Subject: [PATCH] GRETH: GBit transmit descriptor handling optimization
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It is safe to enable all fragments before enabling the first descriptor,
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this way all descriptors don't have to be processed twice, added extra
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memory barrier.
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Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
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---
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drivers/net/greth.c | 19 ++++++++++---------
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1 files changed, 10 insertions(+), 9 deletions(-)
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--- a/drivers/net/greth.c
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+++ b/drivers/net/greth.c
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@@ -512,7 +512,7 @@ greth_start_xmit_gbit(struct sk_buff *sk
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greth->tx_skbuff[curr_tx] = NULL;
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bdp = greth->tx_bd_base + curr_tx;
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- status = GRETH_TXBD_CSALL;
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+ status = GRETH_TXBD_CSALL | GRETH_BD_EN;
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status |= frag->size & GRETH_BD_LEN;
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/* Wrap around descriptor ring */
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@@ -549,26 +549,27 @@ greth_start_xmit_gbit(struct sk_buff *sk
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wmb();
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- /* Enable the descriptors that we configured ... */
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- for (i = 0; i < nr_frags + 1; i++) {
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- bdp = greth->tx_bd_base + greth->tx_next;
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- greth_write_bd(&bdp->stat, greth_read_bd(&bdp->stat) | GRETH_BD_EN);
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- greth->tx_next = NEXT_TX(greth->tx_next);
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- greth->tx_free--;
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- }
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+ /* Enable the descriptor chain by enabling the first descriptor */
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+ bdp = greth->tx_bd_base + greth->tx_next;
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+ greth_write_bd(&bdp->stat, greth_read_bd(&bdp->stat) | GRETH_BD_EN);
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+ greth->tx_next = curr_tx;
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+ greth->tx_free -= nr_frags + 1;
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+
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+ wmb();
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greth_enable_tx(greth);
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return NETDEV_TX_OK;
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frag_map_error:
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- /* Unmap SKB mappings that succeeded */
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+ /* Unmap SKB mappings that succeeded and disable descriptor */
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for (i = 0; greth->tx_next + i != curr_tx; i++) {
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bdp = greth->tx_bd_base + greth->tx_next + i;
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dma_unmap_single(greth->dev,
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greth_read_bd(&bdp->addr),
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greth_read_bd(&bdp->stat) & GRETH_BD_LEN,
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DMA_TO_DEVICE);
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+ greth_write_bd(&bdp->stat, 0);
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}
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map_error:
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if (net_ratelimit())
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