From nobody Fri Feb 13 12:33:10 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57F10CE7A81 for ; Mon, 25 Sep 2023 07:10:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232435AbjIYHKL (ORCPT ); Mon, 25 Sep 2023 03:10:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232426AbjIYHKG (ORCPT ); Mon, 25 Sep 2023 03:10:06 -0400 Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D06D3D3 for ; Mon, 25 Sep 2023 00:09:58 -0700 (PDT) Received: by mail-lf1-x131.google.com with SMTP id 2adb3069b0e04-50306b2920dso7071118e87.0 for ; Mon, 25 Sep 2023 00:09:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1695625797; x=1696230597; darn=vger.kernel.org; h=cc:to:message-id:content-transfer-encoding:mime-version:subject :date:from:from:to:cc:subject:date:message-id:reply-to; bh=EqZK5rfK2NK1ukLToqkFpZ/nmPOVTvrQx25n2XKJyNo=; b=CzxG0qQw3GsFg3Oyc9/jLQtyimetLOpEJ4xl8VmT9JAhYSoJmude0ArvD9vJp+YOr3 7+pWGFXt3tgq+ndwqzAZa8cJ+VgJ1p/HFZ+rADyJmJJAXmNwGSg7x/z7MEQjfDW9Qot6 OCCyZCV3/37I36ZLT2AicvkwiKupCMdFVybQxJTuAhsw7ofYdMU0CY4NuOLJ9Q34FoQU dypU/TMO7T8PP7dISAUhHy+biKrN//ubsZPrivSuxoLrHo4EaLlPpSDB9UATTT9ioJJ0 O0dcjBLh8pB2nN6PGQOVnxmGYsL7sHeuXt1e/qzL33wpnen7QW9fjSBTvRGWFUTfvK18 8Y3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695625797; x=1696230597; h=cc:to:message-id:content-transfer-encoding:mime-version:subject :date:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=EqZK5rfK2NK1ukLToqkFpZ/nmPOVTvrQx25n2XKJyNo=; b=aT7md4rWV/C/BVmETKbKy2ElOO2PkcngTjlCUaEUsc/BCmKJ5YfQGFwbNFAzJwns9o kYPQZqeamyIiHA5N/oKqPAdo482ll4YeshzO8dUb3YhWndKKmDjQxSI0gSXOrKl2Q92y PBh2lghnBasBUmvRhthtjnKQd8WcY0+LCB5vIQfeg5nR3Ii+IbEng3tT9bNG4Uv2rKcD bp8K8dowXbqMAlJBXYrO+VGU2c00nem63Kpi3HS9poLBeMY1y8JWt6arpRu7hcSI1x9c tWN6o4f1A55SbY916YUX6tFDe87QRSCa5ZQMcq3RyK+PpS7bazQp8+GcCkhZJXanahZJ YNgA== X-Gm-Message-State: AOJu0Ywf6bil0PUgpkTteYwRVh6Ky2kOOWT9NcSJXVor9znBnbPxM6D3 b16BiQuQPS+qrbrp19q8oKg1UA== X-Google-Smtp-Source: AGHT+IG50fbbZdBe34ijbBMGdi2JJbwAU5TARGF5Cp2x6RxUr7HavmVYcYtcCvmLfjpZDC+IMKAHFQ== X-Received: by 2002:a05:6512:2804:b0:4fe:3291:6b50 with SMTP id cf4-20020a056512280400b004fe32916b50mr3511955lfb.7.1695625796579; Mon, 25 Sep 2023 00:09:56 -0700 (PDT) Received: from [192.168.1.2] (c-05d8225c.014-348-6c756e10.bbcust.telenor.se. [92.34.216.5]) by smtp.gmail.com with ESMTPSA id x27-20020ac259db000000b004ff6fa3f038sm1705221lfn.144.2023.09.25.00.09.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Sep 2023 00:09:56 -0700 (PDT) From: Linus Walleij Date: Mon, 25 Sep 2023 09:09:52 +0200 Subject: [PATCH net-next v2] net: ixp4xx_eth: Support changing the MTU MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20230925-ixp4xx-eth-mtu-v2-1-393caab75cb0@linaro.org> X-B4-Tracking: v=1; b=H4sIAEAyEWUC/3WNywrDIBBFfyXMulPUBKpd9T9KFnlM4kCrQW2wB P+9kn2Xh8M994BIgSnCvTkg0M6RvaugLg1MdnArIc+VQQnVCqNa5Lx1OSMli+/0wUl0cr7RQqZ VUEdboIXzGXyCo4SOcoK+Gssx+fA9n3Z5+n/RXaJEQ1qPRmiSo3q82A3BX31YoS+l/AB+VPnYt wAAAA== To: Krzysztof Halasa , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Walleij X-Mailer: b4 0.12.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As we don't specify the MTU in the driver, the framework will fall back to 1500 bytes and this doesn't work very well when we try to attach a DSA switch: eth1: mtu greater than device maximum ixp4xx_eth c800a000.ethernet eth1: error -22 setting MTU to 1504 to include DSA overhead After locating an out-of-tree patch in OpenWrt I found suitable code to set the MTU on the interface and ported it and updated it. Now the MTU gets set properly. Signed-off-by: Linus Walleij Reviewed-by: Jacob Keller --- Changes in v2: - Don't just set min/max MTU: implement the interface for actually changing it as well. - Link to v1: https://lore.kernel.org/r/20230923-ixp4xx-eth-mtu-v1-1-9e88b9= 08e1b2@linaro.org --- drivers/net/ethernet/xscale/ixp4xx_eth.c | 64 ++++++++++++++++++++++++++++= +++- 1 file changed, 63 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/xscale/ixp4xx_eth.c b/drivers/net/etherne= t/xscale/ixp4xx_eth.c index 3b0c5f177447..18e52abc005b 100644 --- a/drivers/net/ethernet/xscale/ixp4xx_eth.c +++ b/drivers/net/ethernet/xscale/ixp4xx_eth.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -63,7 +64,15 @@ =20 #define POOL_ALLOC_SIZE (sizeof(struct desc) * (RX_DESCS + TX_DESCS)) #define REGS_SIZE 0x1000 -#define MAX_MRU 1536 /* 0x600 */ + +/* MRU is said to be 14320 in a code dump, the SW manual says that + * MRU/MTU is 16320 and includes VLAN and ethernet headers. + * See "IXP400 Software Programmer's Guide" section 10.3.2, page 161. + * + * FIXME: we have chosen the safe default (14320) but if you can test + * jumboframes, experiment with 16320 and see what happens! + */ +#define MAX_MRU (14320 - VLAN_ETH_HLEN) #define RX_BUFF_SIZE ALIGN((NET_IP_ALIGN) + MAX_MRU, 4) =20 #define NAPI_WEIGHT 16 @@ -1182,6 +1191,53 @@ static void destroy_queues(struct port *port) } } =20 +static int ixp4xx_do_change_mtu(struct net_device *dev, int new_mtu) +{ + struct port *port =3D netdev_priv(dev); + struct npe *npe =3D port->npe; + struct msg msg; + /* adjust for ethernet headers */ + int framesize =3D new_mtu + VLAN_ETH_HLEN; + /* max rx/tx 64 byte chunks */ + int chunks =3D DIV_ROUND_UP(framesize, 64); + + memset(&msg, 0, sizeof(msg)); + msg.cmd =3D NPE_SETMAXFRAMELENGTHS; + msg.eth_id =3D port->id; + + /* Firmware wants to know buffer size in 64 byte chunks */ + msg.byte2 =3D chunks << 8; + msg.byte3 =3D chunks << 8; + + msg.byte4 =3D msg.byte6 =3D framesize >> 8; + msg.byte5 =3D msg.byte7 =3D framesize & 0xff; + + if (npe_send_recv_message(npe, &msg, "ETH_SET_MAX_FRAME_LENGTH")) + return -EIO; + netdev_dbg(dev, "set MTU on NPE %s to %d bytes\n", + npe_name(npe), new_mtu); + + return 0; +} + +static int ixp4xx_eth_change_mtu(struct net_device *dev, int new_mtu) +{ + int ret; + + /* MTU can only be changed when the interface is up. We also + * set the MTU from dev->mtu when opening the device. + */ + if (dev->flags & IFF_UP) { + ret =3D ixp4xx_do_change_mtu(dev, new_mtu); + if (ret < 0) + return ret; + } + + dev->mtu =3D new_mtu; + + return 0; +} + static int eth_open(struct net_device *dev) { struct port *port =3D netdev_priv(dev); @@ -1232,6 +1288,8 @@ static int eth_open(struct net_device *dev) if (npe_send_recv_message(port->npe, &msg, "ETH_SET_FIREWALL_MODE")) return -EIO; =20 + ixp4xx_do_change_mtu(dev, dev->mtu); + if ((err =3D request_queues(port)) !=3D 0) return err; =20 @@ -1374,6 +1432,7 @@ static int eth_close(struct net_device *dev) static const struct net_device_ops ixp4xx_netdev_ops =3D { .ndo_open =3D eth_open, .ndo_stop =3D eth_close, + .ndo_change_mtu =3D ixp4xx_eth_change_mtu, .ndo_start_xmit =3D eth_xmit, .ndo_set_rx_mode =3D eth_set_mcast_list, .ndo_eth_ioctl =3D eth_ioctl, @@ -1488,6 +1547,9 @@ static int ixp4xx_eth_probe(struct platform_device *p= dev) ndev->dev.dma_mask =3D dev->dma_mask; ndev->dev.coherent_dma_mask =3D dev->coherent_dma_mask; =20 + ndev->min_mtu =3D ETH_MIN_MTU; + ndev->max_mtu =3D MAX_MRU; + netif_napi_add_weight(ndev, &port->napi, eth_poll, NAPI_WEIGHT); =20 if (!(port->npe =3D npe_request(NPE_ID(port->id)))) --- base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d change-id: 20230923-ixp4xx-eth-mtu-c041d7efe932 Best regards, --=20 Linus Walleij