kernel/drivers/net/ethernet/freescale/fec_main.c, branch linux-6.18.y

net: fec: account for VLAN header in frame length calculations

2026-01-30T09:32:26Z

commit ca1bb3fedf26a08ed31974131bc0064d4fe33649 upstream. The MAX_FL (maximum frame length) and related calculations used ETH_HLEN, which does not account for the 4-byte VLAN tag in tagged frames. This caused the hardware to reject valid VLAN frames as oversized, resulting in RX errors and dropped packets. Use VLAN_ETH_HLEN instead of ETH_HLEN in the MAX_FL register setup, cut-through mode threshold, buffer allocation, and max_mtu calculation. Cc: stable@kernel.org # v6.18+ Fixes: 62b5bb7be7bc ("net: fec: update MAX_FL based on the current MTU") Fixes: d466c16026e9 ("net: fec: enable the Jumbo frame support for i.MX8QM") Fixes: 59e9bf037d75 ("net: fec: add change_mtu to support dynamic buffer allocation") Fixes: ec2a1681ed4f ("net: fec: use a member variable for maximum buffer size") Signed-off-by: Clemens Gruber Reviewed-by: Wei Fang Link: https://patch.msgid.link/20260121083751.66997-1-mail@clemensgruber.at Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

net: fec: ERR007885 Workaround for XDP TX path

2026-01-02T11:56:43Z

[ Upstream commit e8e032cd24dda7cceaa27bc2eb627f82843f0466 ] The ERR007885 will lead to a TDAR race condition for mutliQ when the driver sets TDAR and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles). And it will cause the udma_tx and udma_tx_arbiter state machines to hang. Therefore, the commit 53bb20d1faba ("net: fec: add variable reg_desc_active to speed things up") and the commit a179aad12bad ("net: fec: ERR007885 Workaround for conventional TX") have added the workaround to fix the potential issue for the conventional TX path. Similarly, the XDP TX path should also have the potential hang issue, so add the workaround for XDP TX path. Fixes: 6d6b39f180b8 ("net: fec: add initial XDP support") Signed-off-by: Wei Fang Link: https://patch.msgid.link/20251128025915.2486943-1-wei.fang@nxp.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: fec: correct rx_bytes statistic for the case SHIFT16 is set

2025-11-08T02:55:27Z

Two additional bytes in front of each frame received into the RX FIFO if SHIFT16 is set, so we need to subtract the extra two bytes from pkt_len to correct the statistic of rx_bytes. Fixes: 3ac72b7b63d5 ("net: fec: align IP header in hardware") Signed-off-by: Wei Fang Reviewed-by: Frank Li Link: https://patch.msgid.link/20251106021421.2096585-1-wei.fang@nxp.com Signed-off-by: Jakub Kicinski

net: fec: enable the Jumbo frame support for i.MX8QM

2025-09-14T21:20:01Z

Certain i.MX SoCs, such as i.MX8QM and i.MX8QXP, feature enhanced FEC hardware that supports Ethernet Jumbo frames with packet sizes up to 16K bytes. When Jumbo frames are supported, the TX FIFO may not be large enough to hold an entire frame. To handle this, the FIFO is configured to operate in cut-through mode when the frame size exceeds (PKT_MAXBUF_SIZE - ETH_HLEN - ETH_FCS_LEN), which allows transmission to begin once the FIFO reaches a certain threshold. Reviewed-by: Wei Fang Signed-off-by: Shenwei Wang Link: https://patch.msgid.link/20250910185211.721341-7-shenwei.wang@nxp.com Signed-off-by: Jakub Kicinski

net: fec: add change_mtu to support dynamic buffer allocation

2025-09-14T21:20:01Z

Add a fec_change_mtu() handler to recalculate the pagepool_order based on the new_mtu value. And update the rx_frame_size accordingly when pagepool_order changes. MTU changes are only allowed when the adater is not running. Reviewed-by: Wei Fang Signed-off-by: Shenwei Wang Link: https://patch.msgid.link/20250910185211.721341-6-shenwei.wang@nxp.com Signed-off-by: Jakub Kicinski

net: fec: add rx_frame_size to support configurable RX length

2025-09-14T21:20:01Z

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 Signed-off-by: Shenwei Wang Link: https://patch.msgid.link/20250910185211.721341-5-shenwei.wang@nxp.com Signed-off-by: Jakub Kicinski

net: fec: update MAX_FL based on the current MTU

2025-09-14T21:20:01Z

Configure the MAX_FL (Maximum Frame Length) register according to the current MTU value, which ensures that packets exceeding the configured MTU trigger an RX error. Reviewed-by: Wei Fang Signed-off-by: Shenwei Wang Link: https://patch.msgid.link/20250910185211.721341-4-shenwei.wang@nxp.com Signed-off-by: Jakub Kicinski

net: fec: add pagepool_order to support variable page size

2025-09-14T21:20:01Z

Add a new pagepool_order member in the fec_enet_private struct to allow dynamic configuration of page size for an instance. This change clears the hardcoded page size assumptions. Reviewed-by: Andrew Lunn Reviewed-by: Wei Fang Signed-off-by: Shenwei Wang Link: https://patch.msgid.link/20250910185211.721341-3-shenwei.wang@nxp.com Signed-off-by: Jakub Kicinski

net: fec: use a member variable for maximum buffer size

2025-09-14T21:20:01Z

Refactor code to support Jumbo frame functionality by adding a member variable in the fec_enet_private structure to store PKT_MAXBUF_SIZE. Remove the OPT_FRAME_SIZE and define a new macro OPT_ARCH_HAS_MAX_FL to indicate architectures that support configurable maximum frame length. And update the MAX_FL register value to max_buf_size when OPT_ARCH_HAS_MAX_FL is defined as 1. Reviewed-by: Andrew Lunn Reviewed-by: Wei Fang Signed-off-by: Shenwei Wang Link: https://patch.msgid.link/20250910185211.721341-2-shenwei.wang@nxp.com Signed-off-by: Jakub Kicinski

net: fec: Fix possible NPD in fec_enet_phy_reset_after_clk_enable()

2025-09-06T00:45:43Z

The function of_phy_find_device may return NULL, so we need to take care before dereferencing phy_dev. Fixes: 64a632da538a ("net: fec: Fix phy_device lookup for phy_reset_after_clk_enable()") Signed-off-by: Stefan Wahren Cc: Christoph Niedermaier Cc: Richard Leitner Reviewed-by: Simon Horman Reviewed-by: Wei Fang Link: https://patch.msgid.link/20250904091334.53965-1-wahrenst@gmx.net Signed-off-by: Jakub Kicinski