xref: /openbmc/linux/net/dsa/dsa.c (revision b8d312aa) 
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");
373