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net: fec: remove rx_align from fec_enet_private

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The rx_align was introduced by the commit 41ef84ce4c ("net: fec: change
FEC alignment according to i.mx6 sx requirement"). Because the i.MX6 SX
requires RX buffer must be 64 bytes alignment.

Since the commit 95698ff617 ("net: fec: using page pool to manage RX
buffers"), the address of the RX buffer is always the page address plus
FEC_ENET_XDP_HEADROOM which is 256 bytes, so the RX buffer is always
64-byte aligned. Therefore, rx_align has no effect since that commit,
and we can safely remove it.

In addition, to prevent future modifications to FEC_ENET_XDP_HEADROOM,
a BUILD_BUG_ON() test has been added to the driver, which ensures that
FEC_ENET_XDP_HEADROOM provides the required alignment.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20251119025148.2817602-5-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Wei Fang
2025-11-19 10:51:47 +08:00
committed by Jakub Kicinski
parent 63083d597a
commit 3bb06c8a46
2 changed files with 14 additions and 6 deletions
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1
drivers/net/ethernet/freescale/fec.h
View File

@@ -660,7 +660,6 @@ struct fec_enet_private {
struct pm_qos_request pm_qos_req;
unsigned int tx_align;
unsigned int rx_align;
/* hw interrupt coalesce */
unsigned int rx_pkts_itr;

19
drivers/net/ethernet/freescale/fec_main.c
View File

@@ -3438,6 +3438,19 @@ fec_enet_alloc_rxq_buffers(struct net_device *ndev, unsigned int queue)
return err;
}
/* Some platforms require the RX buffer must be 64 bytes alignment.
* Some platforms require 16 bytes alignment. And some platforms
* require 4 bytes alignment. But since the page pool have been
* introduced into the driver, the address of RX buffer is always
* the page address plus FEC_ENET_XDP_HEADROOM, and
* FEC_ENET_XDP_HEADROOM is 256 bytes. Therefore, this address can
* satisfy all platforms. To prevent future modifications to
* FEC_ENET_XDP_HEADROOM from ignoring this hardware limitation, a
* BUILD_BUG_ON() test has been added, which ensures that
* FEC_ENET_XDP_HEADROOM provides the required alignment.
*/
BUILD_BUG_ON(FEC_ENET_XDP_HEADROOM & 0x3f);
for (i = 0; i < rxq->bd.ring_size; i++) {
page = page_pool_dev_alloc_pages(rxq->page_pool);
if (!page)
@@ -4072,10 +4085,8 @@ static int fec_enet_init(struct net_device *ndev)
WARN_ON(dsize != (1 << dsize_log2));
#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
fep->rx_align = 0xf;
fep->tx_align = 0xf;
#else
fep->rx_align = 0x3;
fep->tx_align = 0x3;
#endif
fep->rx_pkts_itr = FEC_ITR_ICFT_DEFAULT;
@@ -4164,10 +4175,8 @@ static int fec_enet_init(struct net_device *ndev)
fep->csum_flags |= FLAG_RX_CSUM_ENABLED;
}
if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES) {
if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES)
fep->tx_align = 0;
fep->rx_align = 0x3f;
}
ndev->hw_features = ndev->features;