From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39B5546AEE1; Tue, 16 Jun 2026 18:52:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781635935; cv=none; b=ctud8tiGPR6GhITlF6zjO4GHx51LMdd33J5Eh8XwIe4c11x/96InB55FTMew2xcT5hDU0T3N6Jw4RsVluWqfMLoND7C8MkMZEEnIHQRmotj5I8ADxuGdqhav2xgB/xWHO4vKy9fz4WVTjlybqJe86/JKXP35Y68KVtn9kY7z06g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781635935; c=relaxed/simple; bh=jXEHEcko20YGFCnNG543Cf49U5p9x3Q3OcJcKDMQLYw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e4KJE8wf0DeRdV5pkdkxcF/w/bsNx7ml8XjKJCpjC5gm+AQWqNA/audYarcrFUuoSsn6BSlsoPFX13v0RTiLm5YJBHYDhDFcnQf+zkT475YHdWI6ZkPgeW9L5zI8F8CfeFtSgA5Fp8jxiE8yJy5XM4rj4G1m3PaLjlPXLVAYbNs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=siMvzAMe; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="siMvzAMe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 212681F000E9; Tue, 16 Jun 2026 18:52:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781635934; bh=W4lTSAWLbOqBcawSx8JzEdQcYpzMwQ3LIvGPVcWFDmA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=siMvzAMeExvSpwe9u63CHQ/EEd/pR//lwW84jTpA1x+hGDCGdjCPDdG+dg56Y8iDV 1fR2Spor4qyR6GJTgzKtsByXW9BPNujRXvQ6CLvosgMSWMkMQK8R3nVYHgBUkKcfri w629TaeYVb00TcM5f03Yqaplf5I5qzINTR76mO4Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Thompson , Thangaraj Samynathan , Nicolai Buchwitz , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 143/342] net: lan743x: permit VLAN-tagged packets up to configured MTU Date: Tue, 16 Jun 2026 20:27:19 +0530 Message-ID: <20260616145054.841455606@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145048.348037099@linuxfoundation.org> References: <20260616145048.348037099@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Thompson [ Upstream commit 8173d22b211f615015f7b35f48ab11a6dd78dc99 ] VLAN-tagged interfaces on lan743x devices were previously unreachable via SSH and failed to respond to large ping packets (e.g. "ping -s 1469" given MTU=1500). In these scenarios, "ethtool -S" reports non-zero "RX Oversize Frame Errors". According to Microchip AN2948, the MAC_RX FSE (VLAN field size enforcement) bit determines whether frames with VLAN tags exceeding the base MTU plus tag length are discarded. The driver must set the MAC_RX.FSE bit before setting MAC_RX.RXEN to allow VLAN-tagged frames up to the interface MTU, preventing them from being treated as oversized. As a result, both the base and VLAN-tagged interfaces can use the same MTU without receive errors. Fixes: 23f0703c125b ("lan743x: Add main source files for new lan743x driver") Signed-off-by: David Thompson Reviewed-by: Thangaraj Samynathan Reviewed-by: Nicolai Buchwitz Tested-by: Nicolai Buchwitz # lan7430 on arm64 (RevPi Link: https://patch.msgid.link/20260529210300.433135-1-davthompson@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/microchip/lan743x_main.c | 32 +++++++++++++++++++ drivers/net/ethernet/microchip/lan743x_main.h | 1 + 2 files changed, 33 insertions(+) diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c index 26a230c60efb70..f280fda24f7f07 100644 --- a/drivers/net/ethernet/microchip/lan743x_main.c +++ b/drivers/net/ethernet/microchip/lan743x_main.c @@ -799,6 +799,36 @@ static void lan743x_mac_set_address(struct lan743x_adapter *adapter, "MAC address set to %pM\n", addr); } +static void lan743x_mac_rx_enable_fse(struct lan743x_adapter *adapter) +{ + u32 mac_rx; + bool rxen; + + mac_rx = lan743x_csr_read(adapter, MAC_RX); + if (mac_rx & MAC_RX_FSE_) + return; + + rxen = mac_rx & MAC_RX_RXEN_; + if (rxen) { + mac_rx &= ~MAC_RX_RXEN_; + lan743x_csr_write(adapter, MAC_RX, mac_rx); + lan743x_csr_wait_for_bit(adapter, MAC_RX, MAC_RX_RXD_, + 1, 1000, 20000, 100); + } + + /* Per AN2948, hardware prevents modification of the FSE bit while the + * MAC receiver is enabled (RXEN bit set). Use separate register write + * to assert the FSE bit before enabling the RXEN bit in MAC_RX + */ + mac_rx |= MAC_RX_FSE_; + lan743x_csr_write(adapter, MAC_RX, mac_rx); + + if (rxen) { + mac_rx |= MAC_RX_RXEN_; + lan743x_csr_write(adapter, MAC_RX, mac_rx); + } +} + static int lan743x_mac_init(struct lan743x_adapter *adapter) { bool mac_address_valid = true; @@ -838,6 +868,8 @@ static int lan743x_mac_init(struct lan743x_adapter *adapter) lan743x_mac_set_address(adapter, adapter->mac_address); ether_addr_copy(netdev->dev_addr, adapter->mac_address); + lan743x_mac_rx_enable_fse(adapter); + return 0; } diff --git a/drivers/net/ethernet/microchip/lan743x_main.h b/drivers/net/ethernet/microchip/lan743x_main.h index 2a40cc827b1872..3062c54faffd18 100644 --- a/drivers/net/ethernet/microchip/lan743x_main.h +++ b/drivers/net/ethernet/microchip/lan743x_main.h @@ -118,6 +118,7 @@ #define MAC_RX (0x104) #define MAC_RX_MAX_SIZE_SHIFT_ (16) #define MAC_RX_MAX_SIZE_MASK_ (0x3FFF0000) +#define MAC_RX_FSE_ BIT(2) #define MAC_RX_RXD_ BIT(1) #define MAC_RX_RXEN_ BIT(0) -- 2.53.0