net/dsa/dsa.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/dsa/dsa.c - Hardware switch handling
   4  * Copyright (c) 2008-2009 Marvell Semiconductor
   5  * Copyright (c) 2013 Florian Fainelli <florian@openwrt.org>
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/list.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/slab.h>
  12 #include <linux/module.h>
  13 #include <linux/notifier.h>
  14 #include <linux/of.h>
  15 #include <linux/of_mdio.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/of_net.h>
  18 #include <linux/netdevice.h>
  19 #include <linux/sysfs.h>
  20 #include <linux/phy_fixed.h>
  21 #include <linux/ptp_classify.h>
  22 #include <linux/etherdevice.h>
  23
  24 #include "dsa_priv.h"
  25
  26 static LIST_HEAD(dsa_tag_drivers_list);
  27 static DEFINE_MUTEX(dsa_tag_drivers_lock);
  28
  29 static struct sk_buff *dsa_slave_notag_xmit(struct sk_buff *skb,
  30                                             struct net_device *dev)
  31 {
  32         /* Just return the original SKB */
  33         return skb;
  34 }
  35
  36 static const struct dsa_device_ops none_ops = {
  37         .name   = "none",
  38         .proto  = DSA_TAG_PROTO_NONE,
  39         .xmit   = dsa_slave_notag_xmit,
  40         .rcv    = NULL,
  41 };
  42
  43 DSA_TAG_DRIVER(none_ops);
  44
  45 static void dsa_tag_driver_register(struct dsa_tag_driver *dsa_tag_driver,
  46                                     struct module *owner)
  47 {
  48         dsa_tag_driver->owner = owner;
  49
  50         mutex_lock(&dsa_tag_drivers_lock);
  51         list_add_tail(&dsa_tag_driver->list, &dsa_tag_drivers_list);
  52         mutex_unlock(&dsa_tag_drivers_lock);
  53 }
  54
  55 void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
  56                               unsigned int count, struct module *owner)
  57 {
  58         unsigned int i;
  59
  60         for (i = 0; i < count; i++)
  61                 dsa_tag_driver_register(dsa_tag_driver_array[i], owner);
  62 }
  63
  64 static void dsa_tag_driver_unregister(struct dsa_tag_driver *dsa_tag_driver)
  65 {
  66         mutex_lock(&dsa_tag_drivers_lock);
  67         list_del(&dsa_tag_driver->list);
  68         mutex_unlock(&dsa_tag_drivers_lock);
  69 }
  70 EXPORT_SYMBOL_GPL(dsa_tag_drivers_register);
  71
  72 void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
  73                                 unsigned int count)
  74 {
  75         unsigned int i;
  76
  77         for (i = 0; i < count; i++)
  78                 dsa_tag_driver_unregister(dsa_tag_driver_array[i]);
  79 }
  80 EXPORT_SYMBOL_GPL(dsa_tag_drivers_unregister);
  81
  82 const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops)
  83 {
  84         return ops->name;
  85 };
  86
  87 const struct dsa_device_ops *dsa_tag_driver_get(int tag_protocol)
  88 {
  89         struct dsa_tag_driver *dsa_tag_driver;
  90         const struct dsa_device_ops *ops;
  91         char module_name[128];
  92         bool found = false;
  93
  94         snprintf(module_name, 127, "%s%d", DSA_TAG_DRIVER_ALIAS,
  95                  tag_protocol);
  96
  97         request_module(module_name);
  98
  99         mutex_lock(&dsa_tag_drivers_lock);
 100         list_for_each_entry(dsa_tag_driver, &dsa_tag_drivers_list, list) {
 101                 ops = dsa_tag_driver->ops;
 102                 if (ops->proto == tag_protocol) {
 103                         found = true;
 104                         break;
 105                 }
 106         }
 107
 108         if (found) {
 109                 if (!try_module_get(dsa_tag_driver->owner))
 110                         ops = ERR_PTR(-ENOPROTOOPT);
 111         } else {
 112                 ops = ERR_PTR(-ENOPROTOOPT);
 113         }
 114
 115         mutex_unlock(&dsa_tag_drivers_lock);
 116
 117         return ops;
 118 }
 119
 120 void dsa_tag_driver_put(const struct dsa_device_ops *ops)
 121 {
 122         struct dsa_tag_driver *dsa_tag_driver;
 123
 124         mutex_lock(&dsa_tag_drivers_lock);
 125         list_for_each_entry(dsa_tag_driver, &dsa_tag_drivers_list, list) {
 126                 if (dsa_tag_driver->ops == ops) {
 127                         module_put(dsa_tag_driver->owner);
 128                         break;
 129                 }
 130         }
 131         mutex_unlock(&dsa_tag_drivers_lock);
 132 }
 133
 134 static int dev_is_class(struct device *dev, void *class)
 135 {
 136         if (dev->class != NULL && !strcmp(dev->class->name, class))
 137                 return 1;
 138
 139         return 0;
 140 }
 141
 142 static struct device *dev_find_class(struct device *parent, char *class)
 143 {
 144         if (dev_is_class(parent, class)) {
 145                 get_device(parent);
 146                 return parent;
 147         }
 148
 149         return device_find_child(parent, class, dev_is_class);
 150 }
 151
 152 struct net_device *dsa_dev_to_net_device(struct device *dev)
 153 {
 154         struct device *d;
 155
 156         d = dev_find_class(dev, "net");
 157         if (d != NULL) {
 158                 struct net_device *nd;
 159
 160                 nd = to_net_dev(d);
 161                 dev_hold(nd);
 162                 put_device(d);
 163
 164                 return nd;
 165         }
 166
 167         return NULL;
 168 }
 169 EXPORT_SYMBOL_GPL(dsa_dev_to_net_device);
 170
 171 /* Determine if we should defer delivery of skb until we have a rx timestamp.
 172  *
 173  * Called from dsa_switch_rcv. For now, this will only work if tagging is
 174  * enabled on the switch. Normally the MAC driver would retrieve the hardware
 175  * timestamp when it reads the packet out of the hardware. However in a DSA
 176  * switch, the DSA driver owning the interface to which the packet is
 177  * delivered is never notified unless we do so here.
 178  */
 179 static bool dsa_skb_defer_rx_timestamp(struct dsa_slave_priv *p,
 180                                        struct sk_buff *skb)
 181 {
 182         struct dsa_switch *ds = p->dp->ds;
 183         unsigned int type;
 184
 185         if (skb_headroom(skb) < ETH_HLEN)
 186                 return false;
 187
 188         __skb_push(skb, ETH_HLEN);
 189
 190         type = ptp_classify_raw(skb);
 191
 192         __skb_pull(skb, ETH_HLEN);
 193
 194         if (type == PTP_CLASS_NONE)
 195                 return false;
 196
 197         if (likely(ds->ops->port_rxtstamp))
 198                 return ds->ops->port_rxtstamp(ds, p->dp->index, skb, type);
 199
 200         return false;
 201 }
 202
 203 static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
 204                           struct packet_type *pt, struct net_device *unused)
 205 {
 206         struct dsa_port *cpu_dp = dev->dsa_ptr;
 207         struct sk_buff *nskb = NULL;
 208         struct pcpu_sw_netstats *s;
 209         struct dsa_slave_priv *p;
 210
 211         if (unlikely(!cpu_dp)) {
 212                 kfree_skb(skb);
 213                 return 0;
 214         }
 215
 216         skb = skb_unshare(skb, GFP_ATOMIC);
 217         if (!skb)
 218                 return 0;
 219
 220         nskb = cpu_dp->rcv(skb, dev, pt);
 221         if (!nskb) {
 222                 kfree_skb(skb);
 223                 return 0;
 224         }
 225
 226         skb = nskb;
 227         p = netdev_priv(skb->dev);
 228         skb_push(skb, ETH_HLEN);
 229         skb->pkt_type = PACKET_HOST;
 230         skb->protocol = eth_type_trans(skb, skb->dev);
 231
 232         s = this_cpu_ptr(p->stats64);
 233         u64_stats_update_begin(&s->syncp);
 234         s->rx_packets++;
 235         s->rx_bytes += skb->len;
 236         u64_stats_update_end(&s->syncp);
 237
 238         if (dsa_skb_defer_rx_timestamp(p, skb))
 239                 return 0;
 240
 241         netif_receive_skb(skb);
 242
 243         return 0;
 244 }
 245
 246 #ifdef CONFIG_PM_SLEEP
 247 static bool dsa_is_port_initialized(struct dsa_switch *ds, int p)
 248 {
 249         return dsa_is_user_port(ds, p) && ds->ports[p].slave;
 250 }
 251
 252 int dsa_switch_suspend(struct dsa_switch *ds)
 253 {
 254         int i, ret = 0;
 255
 256         /* Suspend slave network devices */
 257         for (i = 0; i < ds->num_ports; i++) {
 258                 if (!dsa_is_port_initialized(ds, i))
 259                         continue;
 260
 261                 ret = dsa_slave_suspend(ds->ports[i].slave);
 262                 if (ret)
 263                         return ret;
 264         }
 265
 266         if (ds->ops->suspend)
 267                 ret = ds->ops->suspend(ds);
 268
 269         return ret;
 270 }
 271 EXPORT_SYMBOL_GPL(dsa_switch_suspend);
 272
 273 int dsa_switch_resume(struct dsa_switch *ds)
 274 {
 275         int i, ret = 0;
 276
 277         if (ds->ops->resume)
 278                 ret = ds->ops->resume(ds);
 279
 280         if (ret)
 281                 return ret;
 282
 283         /* Resume slave network devices */
 284         for (i = 0; i < ds->num_ports; i++) {
 285                 if (!dsa_is_port_initialized(ds, i))
 286                         continue;
 287
 288                 ret = dsa_slave_resume(ds->ports[i].slave);
 289                 if (ret)
 290                         return ret;
 291         }
 292
 293         return 0;
 294 }
 295 EXPORT_SYMBOL_GPL(dsa_switch_resume);
 296 #endif
 297
 298 static struct packet_type dsa_pack_type __read_mostly = {
 299         .type   = cpu_to_be16(ETH_P_XDSA),
 300         .func   = dsa_switch_rcv,
 301 };
 302
 303 static struct workqueue_struct *dsa_owq;
 304
 305 bool dsa_schedule_work(struct work_struct *work)
 306 {
 307         return queue_work(dsa_owq, work);
 308 }
 309
 310 static ATOMIC_NOTIFIER_HEAD(dsa_notif_chain);
 311
 312 int register_dsa_notifier(struct notifier_block *nb)
 313 {
 314         return atomic_notifier_chain_register(&dsa_notif_chain, nb);
 315 }
 316 EXPORT_SYMBOL_GPL(register_dsa_notifier);
 317
 318 int unregister_dsa_notifier(struct notifier_block *nb)
 319 {
 320         return atomic_notifier_chain_unregister(&dsa_notif_chain, nb);
 321 }
 322 EXPORT_SYMBOL_GPL(unregister_dsa_notifier);
 323
 324 int call_dsa_notifiers(unsigned long val, struct net_device *dev,
 325                        struct dsa_notifier_info *info)
 326 {
 327         info->dev = dev;
 328         return atomic_notifier_call_chain(&dsa_notif_chain, val, info);
 329 }
 330 EXPORT_SYMBOL_GPL(call_dsa_notifiers);
 331
 332 static int __init dsa_init_module(void)
 333 {
 334         int rc;
 335
 336         dsa_owq = alloc_ordered_workqueue("dsa_ordered",
 337                                           WQ_MEM_RECLAIM);
 338         if (!dsa_owq)
 339                 return -ENOMEM;
 340
 341         rc = dsa_slave_register_notifier();
 342         if (rc)
 343                 goto register_notifier_fail;
 344
 345         dev_add_pack(&dsa_pack_type);
 346
 347         dsa_tag_driver_register(&DSA_TAG_DRIVER_NAME(none_ops),
 348                                 THIS_MODULE);
 349
 350         return 0;
 351
 352 register_notifier_fail:
 353         destroy_workqueue(dsa_owq);
 354
 355         return rc;
 356 }
 357 module_init(dsa_init_module);
 358
 359 static void __exit dsa_cleanup_module(void)
 360 {
 361         dsa_tag_driver_unregister(&DSA_TAG_DRIVER_NAME(none_ops));
 362
 363         dsa_slave_unregister_notifier();
 364         dev_remove_pack(&dsa_pack_type);
 365         destroy_workqueue(dsa_owq);
 366 }
 367 module_exit(dsa_cleanup_module);
 368
 369 MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>");
 370 MODULE_DESCRIPTION("Driver for Distributed Switch Architecture switch chips");
 371 MODULE_LICENSE("GPL");
 372 MODULE_ALIAS("platform:dsa");