net/dsa/master.c

   1 /*
   2  * Handling of a master device, switching frames via its switch fabric CPU port
   3  *
   4  * Copyright (c) 2017 Savoir-faire Linux Inc.
   5  *      Vivien Didelot <vivien.didelot@savoirfairelinux.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include "dsa_priv.h"
  14
  15 static void dsa_master_get_ethtool_stats(struct net_device *dev,
  16                                          struct ethtool_stats *stats,
  17                                          uint64_t *data)
  18 {
  19         struct dsa_port *cpu_dp = dev->dsa_ptr;
  20         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
  21         struct dsa_switch *ds = cpu_dp->ds;
  22         int port = cpu_dp->index;
  23         int count = 0;
  24
  25         if (ops->get_sset_count && ops->get_ethtool_stats) {
  26                 count = ops->get_sset_count(dev, ETH_SS_STATS);
  27                 ops->get_ethtool_stats(dev, stats, data);
  28         }
  29
  30         if (ds->ops->get_ethtool_stats)
  31                 ds->ops->get_ethtool_stats(ds, port, data + count);
  32 }
  33
  34 static void dsa_master_get_ethtool_phy_stats(struct net_device *dev,
  35                                              struct ethtool_stats *stats,
  36                                              uint64_t *data)
  37 {
  38         struct dsa_port *cpu_dp = dev->dsa_ptr;
  39         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
  40         struct dsa_switch *ds = cpu_dp->ds;
  41         int port = cpu_dp->index;
  42         int count = 0;
  43
  44         if (dev->phydev && !ops->get_ethtool_phy_stats) {
  45                 count = phy_ethtool_get_sset_count(dev->phydev);
  46                 if (count >= 0)
  47                         phy_ethtool_get_stats(dev->phydev, stats, data);
  48         } else if (ops->get_sset_count && ops->get_ethtool_phy_stats) {
  49                 count = ops->get_sset_count(dev, ETH_SS_PHY_STATS);
  50                 ops->get_ethtool_phy_stats(dev, stats, data);
  51         }
  52
  53         if (count < 0)
  54                 count = 0;
  55
  56         if (ds->ops->get_ethtool_phy_stats)
  57                 ds->ops->get_ethtool_phy_stats(ds, port, data + count);
  58 }
  59
  60 static int dsa_master_get_sset_count(struct net_device *dev, int sset)
  61 {
  62         struct dsa_port *cpu_dp = dev->dsa_ptr;
  63         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
  64         struct dsa_switch *ds = cpu_dp->ds;
  65         int count = 0;
  66
  67         if (sset == ETH_SS_PHY_STATS && dev->phydev &&
  68             !ops->get_ethtool_phy_stats)
  69                 count = phy_ethtool_get_sset_count(dev->phydev);
  70         else if (ops->get_sset_count)
  71                 count = ops->get_sset_count(dev, sset);
  72
  73         if (count < 0)
  74                 count = 0;
  75
  76         if (ds->ops->get_sset_count)
  77                 count += ds->ops->get_sset_count(ds, cpu_dp->index, sset);
  78
  79         return count;
  80 }
  81
  82 static void dsa_master_get_strings(struct net_device *dev, uint32_t stringset,
  83                                    uint8_t *data)
  84 {
  85         struct dsa_port *cpu_dp = dev->dsa_ptr;
  86         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
  87         struct dsa_switch *ds = cpu_dp->ds;
  88         int port = cpu_dp->index;
  89         int len = ETH_GSTRING_LEN;
  90         int mcount = 0, count;
  91         unsigned int i;
  92         uint8_t pfx[4];
  93         uint8_t *ndata;
  94
  95         snprintf(pfx, sizeof(pfx), "p%.2d", port);
  96         /* We do not want to be NULL-terminated, since this is a prefix */
  97         pfx[sizeof(pfx) - 1] = '_';
  98
  99         if (stringset == ETH_SS_PHY_STATS && dev->phydev &&
 100             !ops->get_ethtool_phy_stats) {
 101                 mcount = phy_ethtool_get_sset_count(dev->phydev);
 102                 if (mcount < 0)
 103                         mcount = 0;
 104                 else
 105                         phy_ethtool_get_strings(dev->phydev, data);
 106         } else if (ops->get_sset_count && ops->get_strings) {
 107                 mcount = ops->get_sset_count(dev, stringset);
 108                 if (mcount < 0)
 109                         mcount = 0;
 110                 ops->get_strings(dev, stringset, data);
 111         }
 112
 113         if (ds->ops->get_strings) {
 114                 ndata = data + mcount * len;
 115                 /* This function copies ETH_GSTRINGS_LEN bytes, we will mangle
 116                  * the output after to prepend our CPU port prefix we
 117                  * constructed earlier
 118                  */
 119                 ds->ops->get_strings(ds, port, stringset, ndata);
 120                 count = ds->ops->get_sset_count(ds, port, stringset);
 121                 for (i = 0; i < count; i++) {
 122                         memmove(ndata + (i * len + sizeof(pfx)),
 123                                 ndata + i * len, len - sizeof(pfx));
 124                         memcpy(ndata + i * len, pfx, sizeof(pfx));
 125                 }
 126         }
 127 }
 128
 129 static int dsa_master_ethtool_setup(struct net_device *dev)
 130 {
 131         struct dsa_port *cpu_dp = dev->dsa_ptr;
 132         struct dsa_switch *ds = cpu_dp->ds;
 133         struct ethtool_ops *ops;
 134
 135         ops = devm_kzalloc(ds->dev, sizeof(*ops), GFP_KERNEL);
 136         if (!ops)
 137                 return -ENOMEM;
 138
 139         cpu_dp->orig_ethtool_ops = dev->ethtool_ops;
 140         if (cpu_dp->orig_ethtool_ops)
 141                 memcpy(ops, cpu_dp->orig_ethtool_ops, sizeof(*ops));
 142
 143         ops->get_sset_count = dsa_master_get_sset_count;
 144         ops->get_ethtool_stats = dsa_master_get_ethtool_stats;
 145         ops->get_strings = dsa_master_get_strings;
 146         ops->get_ethtool_phy_stats = dsa_master_get_ethtool_phy_stats;
 147
 148         dev->ethtool_ops = ops;
 149
 150         return 0;
 151 }
 152
 153 static void dsa_master_ethtool_teardown(struct net_device *dev)
 154 {
 155         struct dsa_port *cpu_dp = dev->dsa_ptr;
 156
 157         dev->ethtool_ops = cpu_dp->orig_ethtool_ops;
 158         cpu_dp->orig_ethtool_ops = NULL;
 159 }
 160
 161 static ssize_t tagging_show(struct device *d, struct device_attribute *attr,
 162                             char *buf)
 163 {
 164         struct net_device *dev = to_net_dev(d);
 165         struct dsa_port *cpu_dp = dev->dsa_ptr;
 166
 167         return sprintf(buf, "%s\n",
 168                        dsa_tag_protocol_to_str(cpu_dp->tag_ops));
 169 }
 170 static DEVICE_ATTR_RO(tagging);
 171
 172 static struct attribute *dsa_slave_attrs[] = {
 173         &dev_attr_tagging.attr,
 174         NULL
 175 };
 176
 177 static const struct attribute_group dsa_group = {
 178         .name   = "dsa",
 179         .attrs  = dsa_slave_attrs,
 180 };
 181
 182 static void dsa_master_set_mtu(struct net_device *dev, struct dsa_port *cpu_dp)
 183 {
 184         unsigned int mtu = ETH_DATA_LEN + cpu_dp->tag_ops->overhead;
 185         int err;
 186
 187         rtnl_lock();
 188         if (mtu <= dev->max_mtu) {
 189                 err = dev_set_mtu(dev, mtu);
 190                 if (err)
 191                         netdev_dbg(dev, "Unable to set MTU to include for DSA overheads\n");
 192         }
 193         rtnl_unlock();
 194 }
 195
 196 static void dsa_master_reset_mtu(struct net_device *dev)
 197 {
 198         int err;
 199
 200         rtnl_lock();
 201         err = dev_set_mtu(dev, ETH_DATA_LEN);
 202         if (err)
 203                 netdev_dbg(dev,
 204                            "Unable to reset MTU to exclude DSA overheads\n");
 205         rtnl_unlock();
 206 }
 207
 208 static struct lock_class_key dsa_master_addr_list_lock_key;
 209
 210 int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 211 {
 212         int ret;
 213
 214         dsa_master_set_mtu(dev,  cpu_dp);
 215
 216         /* If we use a tagging format that doesn't have an ethertype
 217          * field, make sure that all packets from this point on get
 218          * sent to the tag format's receive function.
 219          */
 220         wmb();
 221
 222         dev->dsa_ptr = cpu_dp;
 223         lockdep_set_class(&dev->addr_list_lock,
 224                           &dsa_master_addr_list_lock_key);
 225
 226         ret = dsa_master_ethtool_setup(dev);
 227         if (ret)
 228                 return ret;
 229
 230         ret = sysfs_create_group(&dev->dev.kobj, &dsa_group);
 231         if (ret)
 232                 dsa_master_ethtool_teardown(dev);
 233
 234         return ret;
 235 }
 236
 237 void dsa_master_teardown(struct net_device *dev)
 238 {
 239         sysfs_remove_group(&dev->dev.kobj, &dsa_group);
 240         dsa_master_ethtool_teardown(dev);
 241         dsa_master_reset_mtu(dev);
 242
 243         dev->dsa_ptr = NULL;
 244
 245         /* If we used a tagging format that doesn't have an ethertype
 246          * field, make sure that all packets from this point get sent
 247          * without the tag and go through the regular receive path.
 248          */
 249         wmb();
 250 }