1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Handling of a conduit device, switching frames via its switch fabric CPU port
4 *
5 * Copyright (c) 2017 Savoir-faire Linux Inc.
6 * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
7 */
8
9 #include <linux/ethtool.h>
10 #include <linux/netdevice.h>
11 #include <linux/netlink.h>
12 #include <net/dsa.h>
13
14 #include "conduit.h"
15 #include "dsa.h"
16 #include "port.h"
17 #include "tag.h"
18
19 static int dsa_conduit_get_regs_len(struct net_device *dev)
20 {
21 struct dsa_port *cpu_dp = dev->dsa_ptr;
22 const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
23 struct dsa_switch *ds = cpu_dp->ds;
24 int port = cpu_dp->index;
25 int ret = 0;
26 int len;
27
28 if (ops->get_regs_len) {
29 len = ops->get_regs_len(dev);
30 if (len < 0)
31 return len;
32 ret += len;
33 }
34
35 ret += sizeof(struct ethtool_drvinfo);
36 ret += sizeof(struct ethtool_regs);
37
38 if (ds->ops->get_regs_len) {
39 len = ds->ops->get_regs_len(ds, port);
40 if (len < 0)
41 return len;
42 ret += len;
43 }
44
45 return ret;
46 }
47
48 static void dsa_conduit_get_regs(struct net_device *dev,
49 struct ethtool_regs *regs, void *data)
50 {
51 struct dsa_port *cpu_dp = dev->dsa_ptr;
52 const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
53 struct dsa_switch *ds = cpu_dp->ds;
54 struct ethtool_drvinfo *cpu_info;
55 struct ethtool_regs *cpu_regs;
56 int port = cpu_dp->index;
57 int len;
58
59 if (ops->get_regs_len && ops->get_regs) {
60 len = ops->get_regs_len(dev);
61 if (len < 0)
62 return;
63 regs->len = len;
64 ops->get_regs(dev, regs, data);
65 data += regs->len;
66 }
67
68 cpu_info = (struct ethtool_drvinfo *)data;
69 strscpy(cpu_info->driver, "dsa", sizeof(cpu_info->driver));
70 data += sizeof(*cpu_info);
71 cpu_regs = (struct ethtool_regs *)data;
72 data += sizeof(*cpu_regs);
73
74 if (ds->ops->get_regs_len && ds->ops->get_regs) {
75 len = ds->ops->get_regs_len(ds, port);
76 if (len < 0)
77 return;
78 cpu_regs->len = len;
79 ds->ops->get_regs(ds, port, cpu_regs, data);
80 }
81 }
82
83 static void dsa_conduit_get_ethtool_stats(struct net_device *dev,
84 struct ethtool_stats *stats,
85 uint64_t *data)
86 {
87 struct dsa_port *cpu_dp = dev->dsa_ptr;
88 const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
89 struct dsa_switch *ds = cpu_dp->ds;
90 int port = cpu_dp->index;
91 int count = 0;
92
93 if (ops->get_sset_count && ops->get_ethtool_stats) {
94 count = ops->get_sset_count(dev, ETH_SS_STATS);
95 ops->get_ethtool_stats(dev, stats, data);
96 }
97
98 if (ds->ops->get_ethtool_stats)
99 ds->ops->get_ethtool_stats(ds, port, data + count);
100 }
101
102 static void dsa_conduit_get_ethtool_phy_stats(struct net_device *dev,
103 struct ethtool_stats *stats,
104 uint64_t *data)
105 {
106 struct dsa_port *cpu_dp = dev->dsa_ptr;
107 const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
108 struct dsa_switch *ds = cpu_dp->ds;
109 int port = cpu_dp->index;
110 int count = 0;
111
112 if (dev->phydev && !ops->get_ethtool_phy_stats) {
113 count = phy_ethtool_get_sset_count(dev->phydev);
114 if (count >= 0)
115 phy_ethtool_get_stats(dev->phydev, stats, data);
116 } else if (ops->get_sset_count && ops->get_ethtool_phy_stats) {
117 count = ops->get_sset_count(dev, ETH_SS_PHY_STATS);
118 ops->get_ethtool_phy_stats(dev, stats, data);
119 }
120
121 if (count < 0)
122 count = 0;
123
124 if (ds->ops->get_ethtool_phy_stats)
125 ds->ops->get_ethtool_phy_stats(ds, port, data + count);
126 }
127
128 static int dsa_conduit_get_sset_count(struct net_device *dev, int sset)
129 {
130 struct dsa_port *cpu_dp = dev->dsa_ptr;
131 const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
132 struct dsa_switch *ds = cpu_dp->ds;
133 int count = 0;
134
135 if (sset == ETH_SS_PHY_STATS && dev->phydev &&
136 !ops->get_ethtool_phy_stats)
137 count = phy_ethtool_get_sset_count(dev->phydev);
138 else if (ops->get_sset_count)
139 count = ops->get_sset_count(dev, sset);
140
141 if (count < 0)
142 count = 0;
143
144 if (ds->ops->get_sset_count)
145 count += ds->ops->get_sset_count(ds, cpu_dp->index, sset);
146
147 return count;
148 }
149
150 static void dsa_conduit_get_strings(struct net_device *dev, uint32_t stringset,
151 uint8_t *data)
152 {
153 struct dsa_port *cpu_dp = dev->dsa_ptr;
154 const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
155 struct dsa_switch *ds = cpu_dp->ds;
156 int port = cpu_dp->index;
157 int len = ETH_GSTRING_LEN;
158 int mcount = 0, count, i;
159 uint8_t pfx[4];
160 uint8_t *ndata;
161
162 snprintf(pfx, sizeof(pfx), "p%.2d", port);
163 /* We do not want to be NULL-terminated, since this is a prefix */
164 pfx[sizeof(pfx) - 1] = '_';
165
166 if (stringset == ETH_SS_PHY_STATS && dev->phydev &&
167 !ops->get_ethtool_phy_stats) {
168 mcount = phy_ethtool_get_sset_count(dev->phydev);
169 if (mcount < 0)
170 mcount = 0;
171 else
172 phy_ethtool_get_strings(dev->phydev, data);
173 } else if (ops->get_sset_count && ops->get_strings) {
174 mcount = ops->get_sset_count(dev, stringset);
175 if (mcount < 0)
176 mcount = 0;
177 ops->get_strings(dev, stringset, data);
178 }
179
180 if (ds->ops->get_strings) {
181 ndata = data + mcount * len;
182 /* This function copies ETH_GSTRINGS_LEN bytes, we will mangle
183 * the output after to prepend our CPU port prefix we
184 * constructed earlier
185 */
186 ds->ops->get_strings(ds, port, stringset, ndata);
187 count = ds->ops->get_sset_count(ds, port, stringset);
188 if (count < 0)
189 return;
190 for (i = 0; i < count; i++) {
191 memmove(ndata + (i * len + sizeof(pfx)),
192 ndata + i * len, len - sizeof(pfx));
193 memcpy(ndata + i * len, pfx, sizeof(pfx));
194 }
195 }
196 }
197
198 /* Deny PTP operations on conduit if there is at least one switch in the tree
199 * that is PTP capable.
200 */
201 int __dsa_conduit_hwtstamp_validate(struct net_device *dev,
202 const struct kernel_hwtstamp_config *config,
203 struct netlink_ext_ack *extack)
204 {
205 struct dsa_port *cpu_dp = dev->dsa_ptr;
206 struct dsa_switch *ds = cpu_dp->ds;
207 struct dsa_switch_tree *dst;
208 struct dsa_port *dp;
209
210 dst = ds->dst;
211
212 list_for_each_entry(dp, &dst->ports, list) {
213 if (dsa_port_supports_hwtstamp(dp)) {
214 NL_SET_ERR_MSG(extack,
215 "HW timestamping not allowed on DSA conduit when switch supports the operation");
216 return -EBUSY;
217 }
218 }
219
220 return 0;
221 }
222
223 static int dsa_conduit_ethtool_setup(struct net_device *dev)
224 {
225 struct dsa_port *cpu_dp = dev->dsa_ptr;
226 struct dsa_switch *ds = cpu_dp->ds;
227 struct ethtool_ops *ops;
228
229 if (netif_is_lag_master(dev))
230 return 0;
231
232 ops = devm_kzalloc(ds->dev, sizeof(*ops), GFP_KERNEL);
233 if (!ops)
234 return -ENOMEM;
235
236 cpu_dp->orig_ethtool_ops = dev->ethtool_ops;
237 if (cpu_dp->orig_ethtool_ops)
238 memcpy(ops, cpu_dp->orig_ethtool_ops, sizeof(*ops));
239
240 ops->get_regs_len = dsa_conduit_get_regs_len;
241 ops->get_regs = dsa_conduit_get_regs;
242 ops->get_sset_count = dsa_conduit_get_sset_count;
243 ops->get_ethtool_stats = dsa_conduit_get_ethtool_stats;
244 ops->get_strings = dsa_conduit_get_strings;
245 ops->get_ethtool_phy_stats = dsa_conduit_get_ethtool_phy_stats;
246
247 dev->ethtool_ops = ops;
248
249 return 0;
250 }
251
252 static void dsa_conduit_ethtool_teardown(struct net_device *dev)
253 {
254 struct dsa_port *cpu_dp = dev->dsa_ptr;
255
256 if (netif_is_lag_master(dev))
257 return;
258
259 dev->ethtool_ops = cpu_dp->orig_ethtool_ops;
260 cpu_dp->orig_ethtool_ops = NULL;
261 }
262
263 /* Keep the conduit always promiscuous if the tagging protocol requires that
264 * (garbles MAC DA) or if it doesn't support unicast filtering, case in which
265 * it would revert to promiscuous mode as soon as we call dev_uc_add() on it
266 * anyway.
267 */
268 static void dsa_conduit_set_promiscuity(struct net_device *dev, int inc)
269 {
270 const struct dsa_device_ops *ops = dev->dsa_ptr->tag_ops;
271
272 if ((dev->priv_flags & IFF_UNICAST_FLT) && !ops->promisc_on_conduit)
273 return;
274
275 ASSERT_RTNL();
276
277 dev_set_promiscuity(dev, inc);
278 }
279
280 static ssize_t tagging_show(struct device *d, struct device_attribute *attr,
281 char *buf)
282 {
283 struct net_device *dev = to_net_dev(d);
284 struct dsa_port *cpu_dp = dev->dsa_ptr;
285
286 return sysfs_emit(buf, "%s\n",
287 dsa_tag_protocol_to_str(cpu_dp->tag_ops));
288 }
289
290 static ssize_t tagging_store(struct device *d, struct device_attribute *attr,
291 const char *buf, size_t count)
292 {
293 const struct dsa_device_ops *new_tag_ops, *old_tag_ops;
294 const char *end = strchrnul(buf, '\n'), *name;
295 struct net_device *dev = to_net_dev(d);
296 struct dsa_port *cpu_dp = dev->dsa_ptr;
297 size_t len = end - buf;
298 int err;
299
300 /* Empty string passed */
301 if (!len)
302 return -ENOPROTOOPT;
303
304 name = kstrndup(buf, len, GFP_KERNEL);
305 if (!name)
306 return -ENOMEM;
307
308 old_tag_ops = cpu_dp->tag_ops;
309 new_tag_ops = dsa_tag_driver_get_by_name(name);
310 kfree(name);
311 /* Bad tagger name? */
312 if (IS_ERR(new_tag_ops))
313 return PTR_ERR(new_tag_ops);
314
315 if (new_tag_ops == old_tag_ops)
316 /* Drop the temporarily held duplicate reference, since
317 * the DSA switch tree uses this tagger.
318 */
319 goto out;
320
321 err = dsa_tree_change_tag_proto(cpu_dp->ds->dst, new_tag_ops,
322 old_tag_ops);
323 if (err) {
324 /* On failure the old tagger is restored, so we don't need the
325 * driver for the new one.
326 */
327 dsa_tag_driver_put(new_tag_ops);
328 return err;
329 }
330
331 /* On success we no longer need the module for the old tagging protocol
332 */
333 out:
334 dsa_tag_driver_put(old_tag_ops);
335 return count;
336 }
337 static DEVICE_ATTR_RW(tagging);
338
339 static struct attribute *dsa_user_attrs[] = {
340 &dev_attr_tagging.attr,
341 NULL
342 };
343
344 static const struct attribute_group dsa_group = {
345 .name = "dsa",
346 .attrs = dsa_user_attrs,
347 };
348
349 static void dsa_conduit_reset_mtu(struct net_device *dev)
350 {
351 int err;
352
353 err = dev_set_mtu(dev, ETH_DATA_LEN);
354 if (err)
355 netdev_dbg(dev,
356 "Unable to reset MTU to exclude DSA overheads\n");
357 }
358
359 int dsa_conduit_setup(struct net_device *dev, struct dsa_port *cpu_dp)
360 {
361 const struct dsa_device_ops *tag_ops = cpu_dp->tag_ops;
362 struct dsa_switch *ds = cpu_dp->ds;
363 struct device_link *consumer_link;
364 int mtu, ret;
365
366 mtu = ETH_DATA_LEN + dsa_tag_protocol_overhead(tag_ops);
367
368 /* The DSA conduit must use SET_NETDEV_DEV for this to work. */
369 if (!netif_is_lag_master(dev)) {
370 consumer_link = device_link_add(ds->dev, dev->dev.parent,
371 DL_FLAG_AUTOREMOVE_CONSUMER);
372 if (!consumer_link)
373 netdev_err(dev,
374 "Failed to create a device link to DSA switch %s\n",
375 dev_name(ds->dev));
376 }
377
378 /* The switch driver may not implement ->port_change_mtu(), case in
379 * which dsa_user_change_mtu() will not update the conduit MTU either,
380 * so we need to do that here.
381 */
382 ret = dev_set_mtu(dev, mtu);
383 if (ret)
384 netdev_warn(dev, "error %d setting MTU to %d to include DSA overhead\n",
385 ret, mtu);
386
387 /* If we use a tagging format that doesn't have an ethertype
388 * field, make sure that all packets from this point on get
389 * sent to the tag format's receive function.
390 */
391 wmb();
392
393 dev->dsa_ptr = cpu_dp;
394
395 dsa_conduit_set_promiscuity(dev, 1);
396
397 ret = dsa_conduit_ethtool_setup(dev);
398 if (ret)
399 goto out_err_reset_promisc;
400
401 ret = sysfs_create_group(&dev->dev.kobj, &dsa_group);
402 if (ret)
403 goto out_err_ethtool_teardown;
404
405 return ret;
406
407 out_err_ethtool_teardown:
408 dsa_conduit_ethtool_teardown(dev);
409 out_err_reset_promisc:
410 dsa_conduit_set_promiscuity(dev, -1);
411 return ret;
412 }
413
414 void dsa_conduit_teardown(struct net_device *dev)
415 {
416 sysfs_remove_group(&dev->dev.kobj, &dsa_group);
417 dsa_conduit_ethtool_teardown(dev);
418 dsa_conduit_reset_mtu(dev);
419 dsa_conduit_set_promiscuity(dev, -1);
420
421 dev->dsa_ptr = NULL;
422
423 /* If we used a tagging format that doesn't have an ethertype
424 * field, make sure that all packets from this point get sent
425 * without the tag and go through the regular receive path.
426 */
427 wmb();
428 }
429
430 int dsa_conduit_lag_setup(struct net_device *lag_dev, struct dsa_port *cpu_dp,
431 struct netdev_lag_upper_info *uinfo,
432 struct netlink_ext_ack *extack)
433 {
434 bool conduit_setup = false;
435 int err;
436
437 if (!netdev_uses_dsa(lag_dev)) {
438 err = dsa_conduit_setup(lag_dev, cpu_dp);
439 if (err)
440 return err;
441
442 conduit_setup = true;
443 }
444
445 err = dsa_port_lag_join(cpu_dp, lag_dev, uinfo, extack);
446 if (err) {
447 NL_SET_ERR_MSG_WEAK_MOD(extack, "CPU port failed to join LAG");
448 goto out_conduit_teardown;
449 }
450
451 return 0;
452
453 out_conduit_teardown:
454 if (conduit_setup)
455 dsa_conduit_teardown(lag_dev);
456 return err;
457 }
458
459 /* Tear down a conduit if there isn't any other user port on it,
460 * optionally also destroying LAG information.
461 */
462 void dsa_conduit_lag_teardown(struct net_device *lag_dev,
463 struct dsa_port *cpu_dp)
464 {
465 struct net_device *upper;
466 struct list_head *iter;
467
468 dsa_port_lag_leave(cpu_dp, lag_dev);
469
470 netdev_for_each_upper_dev_rcu(lag_dev, upper, iter)
471 if (dsa_user_dev_check(upper))
472 return;
473
474 dsa_conduit_teardown(lag_dev);
475 }
476
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