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| author | Eric Nelson <eric@nelint.com> | 2016-09-24 07:42:19 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-27 07:39:34 -0400 |
| commit | 3ac72b7b63d57b231dda1e8f8d13872e0d7e8603 (patch) | |
| tree | daf1ca189ea3eb820b243e1752a6be19bdbdfbfb /drivers | |
| parent | 97dc499c1ae396bc0d529f5b1aef3138de1ae7de (diff) | |
| download | linux-0-day-3ac72b7b63d57b231dda1e8f8d13872e0d7e8603.tar.gz linux-0-day-3ac72b7b63d57b231dda1e8f8d13872e0d7e8603.tar.xz | |
net: fec: align IP header in hardware
The FEC receive accelerator (RACC) supports shifting the data payload of
received packets by 16-bits, which aligns the payload (IP header) on a
4-byte boundary, which is, if not required, at least strongly suggested
by the Linux networking layer.
Without this patch, a huge number of alignment faults will be taken by the
IP stack, as seen in /proc/cpu/alignment:
~/$ cat /proc/cpu/alignment
User: 0
System: 72645 (inet_gro_receive+0x104/0x27c)
Skipped: 0
Half: 0
Word: 0
DWord: 0
Multi: 72645
User faults: 3 (fixup+warn)
This patch was suggested by Andrew Lunn in this message to linux-netdev:
http://marc.info/?l=linux-arm-kernel&m=147465452108384&w=2
and adapted from a patch by Russell King from 2014:
http://git.arm.linux.org.uk/cgit/linux-arm.git/commit/?id=70d8a8a
Signed-off-by: Eric Nelson <eric@nelint.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/ethernet/freescale/fec_main.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 3fb11f929adc8..692ee248e4864 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -180,6 +180,7 @@ MODULE_PARM_DESC(macaddr, "FEC Ethernet MAC address"); /* FEC receive acceleration */ #define FEC_RACC_IPDIS (1 << 1) #define FEC_RACC_PRODIS (1 << 2) +#define FEC_RACC_SHIFT16 BIT(7) #define FEC_RACC_OPTIONS (FEC_RACC_IPDIS | FEC_RACC_PRODIS) /* @@ -945,9 +946,11 @@ fec_restart(struct net_device *ndev) #if !defined(CONFIG_M5272) if (fep->quirks & FEC_QUIRK_HAS_RACC) { - /* set RX checksum */ val = readl(fep->hwp + FEC_RACC); + /* align IP header */ + val |= FEC_RACC_SHIFT16; if (fep->csum_flags & FLAG_RX_CSUM_ENABLED) + /* set RX checksum */ val |= FEC_RACC_OPTIONS; else val &= ~FEC_RACC_OPTIONS; @@ -1428,6 +1431,12 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id) prefetch(skb->data - NET_IP_ALIGN); skb_put(skb, pkt_len - 4); data = skb->data; + +#if !defined(CONFIG_M5272) + if (fep->quirks & FEC_QUIRK_HAS_RACC) + data = skb_pull_inline(skb, 2); +#endif + if (!is_copybreak && need_swap) swap_buffer(data, pkt_len); |