133 lines
4.0 KiB
Diff
133 lines
4.0 KiB
Diff
From 6599df775e2cbb4988bdf8239acf4fbec70e5ef9 Mon Sep 17 00:00:00 2001
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From: Linus Walleij <linus.walleij@linaro.org>
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Date: Sat, 23 Sep 2023 20:38:22 +0200
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Subject: [PATCH 3/4] net: ixp4xx_eth: Support changing the MTU
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As we don't specify the MTU in the driver, the framework
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will fall back to 1500 bytes and this doesn't work very
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well when we try to attach a DSA switch:
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eth1: mtu greater than device maximum
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ixp4xx_eth c800a000.ethernet eth1: error -22 setting
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MTU to 1504 to include DSA overhead
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After locating an out-of-tree patch in OpenWrt I found
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suitable code to set the MTU on the interface and ported
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it and updated it. Now the MTU gets set properly.
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Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
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Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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---
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drivers/net/ethernet/xscale/ixp4xx_eth.c | 65 +++++++++++++++++++++++-
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1 file changed, 64 insertions(+), 1 deletion(-)
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--- a/drivers/net/ethernet/xscale/ixp4xx_eth.c
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+++ b/drivers/net/ethernet/xscale/ixp4xx_eth.c
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@@ -24,6 +24,7 @@
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#include <linux/dma-mapping.h>
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#include <linux/dmapool.h>
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#include <linux/etherdevice.h>
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+#include <linux/if_vlan.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/net_tstamp.h>
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@@ -63,7 +64,15 @@
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#define POOL_ALLOC_SIZE (sizeof(struct desc) * (RX_DESCS + TX_DESCS))
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#define REGS_SIZE 0x1000
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-#define MAX_MRU 1536 /* 0x600 */
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+
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+/* MRU is said to be 14320 in a code dump, the SW manual says that
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+ * MRU/MTU is 16320 and includes VLAN and ethernet headers.
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+ * See "IXP400 Software Programmer's Guide" section 10.3.2, page 161.
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+ *
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+ * FIXME: we have chosen the safe default (14320) but if you can test
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+ * jumboframes, experiment with 16320 and see what happens!
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+ */
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+#define MAX_MRU (14320 - VLAN_ETH_HLEN)
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#define RX_BUFF_SIZE ALIGN((NET_IP_ALIGN) + MAX_MRU, 4)
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#define NAPI_WEIGHT 16
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@@ -1182,6 +1191,54 @@ static void destroy_queues(struct port *
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}
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}
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+static int ixp4xx_do_change_mtu(struct net_device *dev, int new_mtu)
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+{
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+ struct port *port = netdev_priv(dev);
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+ struct npe *npe = port->npe;
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+ int framesize, chunks;
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+ struct msg msg = {};
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+
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+ /* adjust for ethernet headers */
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+ framesize = new_mtu + VLAN_ETH_HLEN;
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+ /* max rx/tx 64 byte chunks */
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+ chunks = DIV_ROUND_UP(framesize, 64);
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+
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+ msg.cmd = NPE_SETMAXFRAMELENGTHS;
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+ msg.eth_id = port->id;
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+
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+ /* Firmware wants to know buffer size in 64 byte chunks */
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+ msg.byte2 = chunks << 8;
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+ msg.byte3 = chunks << 8;
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+
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+ msg.byte4 = msg.byte6 = framesize >> 8;
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+ msg.byte5 = msg.byte7 = framesize & 0xff;
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+
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+ if (npe_send_recv_message(npe, &msg, "ETH_SET_MAX_FRAME_LENGTH"))
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+ return -EIO;
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+ netdev_dbg(dev, "set MTU on NPE %s to %d bytes\n",
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+ npe_name(npe), new_mtu);
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+
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+ return 0;
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+}
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+
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+static int ixp4xx_eth_change_mtu(struct net_device *dev, int new_mtu)
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+{
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+ int ret;
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+
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+ /* MTU can only be changed when the interface is up. We also
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+ * set the MTU from dev->mtu when opening the device.
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+ */
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+ if (dev->flags & IFF_UP) {
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+ ret = ixp4xx_do_change_mtu(dev, new_mtu);
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+ if (ret < 0)
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+ return ret;
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+ }
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+
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+ dev->mtu = new_mtu;
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+
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+ return 0;
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+}
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+
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static int eth_open(struct net_device *dev)
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{
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struct port *port = netdev_priv(dev);
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@@ -1232,6 +1289,8 @@ static int eth_open(struct net_device *d
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if (npe_send_recv_message(port->npe, &msg, "ETH_SET_FIREWALL_MODE"))
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return -EIO;
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+ ixp4xx_do_change_mtu(dev, dev->mtu);
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+
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if ((err = request_queues(port)) != 0)
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return err;
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@@ -1374,6 +1433,7 @@ static int eth_close(struct net_device *
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static const struct net_device_ops ixp4xx_netdev_ops = {
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.ndo_open = eth_open,
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.ndo_stop = eth_close,
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+ .ndo_change_mtu = ixp4xx_eth_change_mtu,
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.ndo_start_xmit = eth_xmit,
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.ndo_set_rx_mode = eth_set_mcast_list,
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.ndo_eth_ioctl = eth_ioctl,
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@@ -1488,6 +1548,9 @@ static int ixp4xx_eth_probe(struct platf
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ndev->dev.dma_mask = dev->dma_mask;
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ndev->dev.coherent_dma_mask = dev->coherent_dma_mask;
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+ ndev->min_mtu = ETH_MIN_MTU;
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+ ndev->max_mtu = MAX_MRU;
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+
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netif_napi_add_weight(ndev, &port->napi, eth_poll, NAPI_WEIGHT);
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if (!(port->npe = npe_request(NPE_ID(port->id))))
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