diff options
Diffstat (limited to 'target/linux/leon/patches/020-greth_optimize_gbit_tx_descriptor_handling.patch')
| -rw-r--r-- | target/linux/leon/patches/020-greth_optimize_gbit_tx_descriptor_handling.patch | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/target/linux/leon/patches/020-greth_optimize_gbit_tx_descriptor_handling.patch b/target/linux/leon/patches/020-greth_optimize_gbit_tx_descriptor_handling.patch new file mode 100644 index 000000000..3a14eb76d --- /dev/null +++ b/target/linux/leon/patches/020-greth_optimize_gbit_tx_descriptor_handling.patch @@ -0,0 +1,61 @@ +From 544631281bed5cc37b8f2d3a99f44c9d4b97f9a8 Mon Sep 17 00:00:00 2001 +From: Daniel Hellstrom <daniel@gaisler.com> +Date: Wed, 1 Dec 2010 10:07:12 +0100 +Subject: [PATCH] GRETH: GBit transmit descriptor handling optimization + +It is safe to enable all fragments before enabling the first descriptor, +this way all descriptors don't have to be processed twice, added extra +memory barrier. + +Signed-off-by: Daniel Hellstrom <daniel@gaisler.com> +--- + drivers/net/greth.c | 19 ++++++++++--------- + 1 files changed, 10 insertions(+), 9 deletions(-) + +--- a/drivers/net/greth.c ++++ b/drivers/net/greth.c +@@ -512,7 +512,7 @@ greth_start_xmit_gbit(struct sk_buff *sk + greth->tx_skbuff[curr_tx] = NULL; + bdp = greth->tx_bd_base + curr_tx; + +- status = GRETH_TXBD_CSALL; ++ status = GRETH_TXBD_CSALL | GRETH_BD_EN; + status |= frag->size & GRETH_BD_LEN; + + /* Wrap around descriptor ring */ +@@ -549,26 +549,27 @@ greth_start_xmit_gbit(struct sk_buff *sk + + wmb(); + +- /* Enable the descriptors that we configured ... */ +- for (i = 0; i < nr_frags + 1; i++) { +- bdp = greth->tx_bd_base + greth->tx_next; +- greth_write_bd(&bdp->stat, greth_read_bd(&bdp->stat) | GRETH_BD_EN); +- greth->tx_next = NEXT_TX(greth->tx_next); +- greth->tx_free--; +- } ++ /* Enable the descriptor chain by enabling the first descriptor */ ++ bdp = greth->tx_bd_base + greth->tx_next; ++ greth_write_bd(&bdp->stat, greth_read_bd(&bdp->stat) | GRETH_BD_EN); ++ greth->tx_next = curr_tx; ++ greth->tx_free -= nr_frags + 1; ++ ++ wmb(); + + greth_enable_tx(greth); + + return NETDEV_TX_OK; + + frag_map_error: +- /* Unmap SKB mappings that succeeded */ ++ /* Unmap SKB mappings that succeeded and disable descriptor */ + for (i = 0; greth->tx_next + i != curr_tx; i++) { + bdp = greth->tx_bd_base + greth->tx_next + i; + dma_unmap_single(greth->dev, + greth_read_bd(&bdp->addr), + greth_read_bd(&bdp->stat) & GRETH_BD_LEN, + DMA_TO_DEVICE); ++ greth_write_bd(&bdp->stat, 0); + } + map_error: + if (net_ratelimit()) |