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
128 bytes, so RX buffer is always 64-byte aligned. Therefore, rx_align
has no effect since that commit, and we can safely remove it.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
---
 drivers/net/ethernet/freescale/fec.h      | 1 -
 drivers/net/ethernet/freescale/fec_main.c | 6 +-----
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index c5bbc2c16a4f..a25dca9c7d71 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 5de86c8bc78e..cf598d5260fb 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -4069,10 +4069,8 @@ 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;
@@ -4161,10 +4159,8 @@ 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;
 
-- 
2.34.1

On Tue, Nov 11, 2025 at 06:00:56PM +0800, Wei Fang wrote:
> 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
> 128 bytes, so RX buffer is always 64-byte aligned.

It is not obvious to me where this 128 bytes is added.

	Andrew

On Tue, Nov 11, 2025 at 06:00:56PM +0800, Wei Fang wrote:
> 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
> 128 bytes, so RX buffer is always 64-byte aligned. Therefore, rx_align
> has no effect since that commit, and we can safely remove it.

I suggest keep it as it because we need know this kind limitation in case
future code change broke prediction
'net: fec: using page pool to manage RX ..."

Frank
>
> Signed-off-by: Wei Fang <wei.fang@nxp.com>
> ---
>  drivers/net/ethernet/freescale/fec.h      | 1 -
>  drivers/net/ethernet/freescale/fec_main.c | 6 +-----
>  2 files changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
> index c5bbc2c16a4f..a25dca9c7d71 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 5de86c8bc78e..cf598d5260fb 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -4069,10 +4069,8 @@ 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;
> @@ -4161,10 +4159,8 @@ 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;
>
> --
> 2.34.1
>