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[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 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@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-v1-1-9e88b908e1b2@linaro.org --- drivers/net/ethernet/xscale/ixp4xx_eth.c | 64 +++++++++++++++++++++++++++++++- 1 file changed, 63 insertions(+), 1 deletion(-) --- base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d change-id: 20230923-ixp4xx-eth-mtu-c041d7efe932 Best regards, diff --git a/drivers/net/ethernet/xscale/ixp4xx_eth.c b/drivers/net/ethernet/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 @@ #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) #define NAPI_WEIGHT 16 @@ -1182,6 +1191,53 @@ static void destroy_queues(struct port *port) } } +static int ixp4xx_do_change_mtu(struct net_device *dev, int new_mtu) +{ + struct port *port = netdev_priv(dev); + struct npe *npe = port->npe; + struct msg msg; + /* adjust for ethernet headers */ + int framesize = new_mtu + VLAN_ETH_HLEN; + /* max rx/tx 64 byte chunks */ + int chunks = DIV_ROUND_UP(framesize, 64); + + memset(&msg, 0, sizeof(msg)); + msg.cmd = NPE_SETMAXFRAMELENGTHS; + msg.eth_id = port->id; + + /* Firmware wants to know buffer size in 64 byte chunks */ + msg.byte2 = chunks << 8; + msg.byte3 = chunks << 8; + + msg.byte4 = msg.byte6 = framesize >> 8; + msg.byte5 = msg.byte7 = 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 = ixp4xx_do_change_mtu(dev, new_mtu); + if (ret < 0) + return ret; + } + + dev->mtu = new_mtu; + + return 0; +} + static int eth_open(struct net_device *dev) { struct port *port = 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; + ixp4xx_do_change_mtu(dev, dev->mtu); + if ((err = request_queues(port)) != 0) return err; @@ -1374,6 +1432,7 @@ static int eth_close(struct net_device *dev) static const struct net_device_ops ixp4xx_netdev_ops = { .ndo_open = eth_open, .ndo_stop = eth_close, + .ndo_change_mtu = ixp4xx_eth_change_mtu, .ndo_start_xmit = eth_xmit, .ndo_set_rx_mode = eth_set_mcast_list, .ndo_eth_ioctl = eth_ioctl, @@ -1488,6 +1547,9 @@ static int ixp4xx_eth_probe(struct platform_device *pdev) ndev->dev.dma_mask = dev->dma_mask; ndev->dev.coherent_dma_mask = dev->coherent_dma_mask; + ndev->min_mtu = ETH_MIN_MTU; + ndev->max_mtu = MAX_MRU; + netif_napi_add_weight(ndev, &port->napi, eth_poll, NAPI_WEIGHT); if (!(port->npe = npe_request(NPE_ID(port->id))))