net: fec: add rx_frame_size to support configurable RX length

Add a new rx_frame_size member in the fec_enet_private structure to
track the RX buffer size. On the Jumbo frame enabled system, the value
will be recalculated whenever the MTU is updated, allowing the driver
to allocate RX buffer efficiently.

Configure the TRUNC_FL (Frame Truncation Length) based on the smaller
value between max_buf_size and the rx_frame_size to maintain consistent
RX error behavior, regardless of whether Jumbo frames are enabled.

Reviewed-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://patch.msgid.link/20250910185211.721341-5-shenwei.wang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 47317346b2f313325600d6c6852e3270924e1229..f1032a11aa7680df219d437329ba946bae9c5c3c 100644 (file)
--- 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 7bc1fe2c13ed605f3811663a38962365592339ad..d71d0d4f5597176005d3f2cc076df909447f14dc 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -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(min(fep->rx_frame_size, fep->max_buf_size), fep->hwp + FEC_FTRL);
        }
 #endif
 
@@ -4565,6 +4565,7 @@ 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;