From 3bb06c8a461b8c8714eef5094b1fadd2d066dd1a Mon Sep 17 00:00:00 2001 From: Wei Fang Date: Wed, 19 Nov 2025 10:51:47 +0800 Subject: [PATCH] net: fec: remove rx_align from fec_enet_private The rx_align was introduced by the commit 41ef84ce4c72 ("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 95698ff6177b ("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 Link: https://patch.msgid.link/20251119025148.2817602-5-wei.fang@nxp.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/freescale/fec.h | 1 - drivers/net/ethernet/freescale/fec_main.c | 19 ++++++++++++++----- 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h index c5bbc2c16a4f9..a25dca9c7d717 100644 --- a/drivers/net/ethernet/freescale/fec.h +++ b/drivers/net/ethernet/freescale/fec.h @@ -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; diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 6c19be0618ae0..c82be43b19abe 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -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; -- 2.47.3