Add a new rx_frame_size member in the fec_enet_private structure to
decouple frame size configuration from max_buf_size. This allows more
precise control over RX frame length settings. It is particularly useful
for Jumbo frame support because the RX frame size may possible larger than
the allocated RX buffer.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
---
 drivers/net/ethernet/freescale/fec.h      | 1 +
 drivers/net/ethernet/freescale/fec_main.c | 7 ++++---
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 47317346b2f3..f1032a11aa76 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -621,6 +621,7 @@ struct fec_enet_private {
 	unsigned int total_rx_ring_size;
 	unsigned int max_buf_size;
 	unsigned int pagepool_order;
+	unsigned int rx_frame_size;
 
 	struct	platform_device *pdev;
 
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index b6ce56051c79..6d0d97bb077c 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1148,8 +1148,8 @@ fec_restart(struct net_device *ndev)
 	u32 rcntl = FEC_RCR_MII;
 	u32 ecntl = FEC_ECR_ETHEREN;
 
-	if (fep->max_buf_size == OPT_FRAME_SIZE)
-		rcntl |= (fep->max_buf_size << 16);
+	if (OPT_FRAME_SIZE != 0)
+		rcntl |= (fep->rx_frame_size << 16);
 
 	if (fep->bufdesc_ex)
 		fec_ptp_save_state(fep);
@@ -1194,7 +1194,7 @@ fec_restart(struct net_device *ndev)
 		else
 			val &= ~FEC_RACC_OPTIONS;
 		writel(val, fep->hwp + FEC_RACC);
-		writel(fep->max_buf_size, fep->hwp + FEC_FTRL);
+		writel(fep->rx_frame_size, fep->hwp + FEC_FTRL);
 	}
 #endif
 
@@ -4563,6 +4563,7 @@ fec_probe(struct platform_device *pdev)
 	pinctrl_pm_select_sleep_state(&pdev->dev);
 
 	fep->pagepool_order = 0;
+	fep->rx_frame_size = FEC_ENET_RX_FRSIZE;
 	fep->max_buf_size = PKT_MAXBUF_SIZE;
 	ndev->max_mtu = fep->max_buf_size - ETH_HLEN - ETH_FCS_LEN;
 
-- 
2.43.0