xref: /openbmc/linux/net/dsa/dsa.c (revision e190bfe5) 
1 /*
2  * net/dsa/dsa.c - Hardware switch handling
3  * Copyright (c) 2008-2009 Marvell Semiconductor
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  */
10 
11 #include <linux/list.h>
12 #include <linux/netdevice.h>
13 #include <linux/platform_device.h>
14 #include <linux/slab.h>
15 #include <net/dsa.h>
16 #include "dsa_priv.h"
17 
18 char dsa_driver_version[] = "0.1";
19 
20 
21 /* switch driver registration ***********************************************/
22 static DEFINE_MUTEX(dsa_switch_drivers_mutex);
23 static LIST_HEAD(dsa_switch_drivers);
24 
25 void register_switch_driver(struct dsa_switch_driver *drv)
26 {
27 	mutex_lock(&dsa_switch_drivers_mutex);
28 	list_add_tail(&drv->list, &dsa_switch_drivers);
29 	mutex_unlock(&dsa_switch_drivers_mutex);
30 }
31 
32 void unregister_switch_driver(struct dsa_switch_driver *drv)
33 {
34 	mutex_lock(&dsa_switch_drivers_mutex);
35 	list_del_init(&drv->list);
36 	mutex_unlock(&dsa_switch_drivers_mutex);
37 }
38 
39 static struct dsa_switch_driver *
40 dsa_switch_probe(struct mii_bus *bus, int sw_addr, char **_name)
41 {
42 	struct dsa_switch_driver *ret;
43 	struct list_head *list;
44 	char *name;
45 
46 	ret = NULL;
47 	name = NULL;
48 
49 	mutex_lock(&dsa_switch_drivers_mutex);
50 	list_for_each(list, &dsa_switch_drivers) {
51 		struct dsa_switch_driver *drv;
52 
53 		drv = list_entry(list, struct dsa_switch_driver, list);
54 
55 		name = drv->probe(bus, sw_addr);
56 		if (name != NULL) {
57 			ret = drv;
58 			break;
59 		}
60 	}
61 	mutex_unlock(&dsa_switch_drivers_mutex);
62 
63 	*_name = name;
64 
65 	return ret;
66 }
67 
68 
69 /* basic switch operations **************************************************/
70 static struct dsa_switch *
71 dsa_switch_setup(struct dsa_switch_tree *dst, int index,
72 		 struct device *parent, struct mii_bus *bus)
73 {
74 	struct dsa_chip_data *pd = dst->pd->chip + index;
75 	struct dsa_switch_driver *drv;
76 	struct dsa_switch *ds;
77 	int ret;
78 	char *name;
79 	int i;
80 
81 	/*
82 	 * Probe for switch model.
83 	 */
84 	drv = dsa_switch_probe(bus, pd->sw_addr, &name);
85 	if (drv == NULL) {
86 		printk(KERN_ERR "%s[%d]: could not detect attached switch\n",
87 		       dst->master_netdev->name, index);
88 		return ERR_PTR(-EINVAL);
89 	}
90 	printk(KERN_INFO "%s[%d]: detected a %s switch\n",
91 		dst->master_netdev->name, index, name);
92 
93 
94 	/*
95 	 * Allocate and initialise switch state.
96 	 */
97 	ds = kzalloc(sizeof(*ds) + drv->priv_size, GFP_KERNEL);
98 	if (ds == NULL)
99 		return ERR_PTR(-ENOMEM);
100 
101 	ds->dst = dst;
102 	ds->index = index;
103 	ds->pd = dst->pd->chip + index;
104 	ds->drv = drv;
105 	ds->master_mii_bus = bus;
106 
107 
108 	/*
109 	 * Validate supplied switch configuration.
110 	 */
111 	for (i = 0; i < DSA_MAX_PORTS; i++) {
112 		char *name;
113 
114 		name = pd->port_names[i];
115 		if (name == NULL)
116 			continue;
117 
118 		if (!strcmp(name, "cpu")) {
119 			if (dst->cpu_switch != -1) {
120 				printk(KERN_ERR "multiple cpu ports?!\n");
121 				ret = -EINVAL;
122 				goto out;
123 			}
124 			dst->cpu_switch = index;
125 			dst->cpu_port = i;
126 		} else if (!strcmp(name, "dsa")) {
127 			ds->dsa_port_mask |= 1 << i;
128 		} else {
129 			ds->phys_port_mask |= 1 << i;
130 		}
131 	}
132 
133 
134 	/*
135 	 * If the CPU connects to this switch, set the switch tree
136 	 * tagging protocol to the preferred tagging format of this
137 	 * switch.
138 	 */
139 	if (ds->dst->cpu_switch == index)
140 		ds->dst->tag_protocol = drv->tag_protocol;
141 
142 
143 	/*
144 	 * Do basic register setup.
145 	 */
146 	ret = drv->setup(ds);
147 	if (ret < 0)
148 		goto out;
149 
150 	ret = drv->set_addr(ds, dst->master_netdev->dev_addr);
151 	if (ret < 0)
152 		goto out;
153 
154 	ds->slave_mii_bus = mdiobus_alloc();
155 	if (ds->slave_mii_bus == NULL) {
156 		ret = -ENOMEM;
157 		goto out;
158 	}
159 	dsa_slave_mii_bus_init(ds);
160 
161 	ret = mdiobus_register(ds->slave_mii_bus);
162 	if (ret < 0)
163 		goto out_free;
164 
165 
166 	/*
167 	 * Create network devices for physical switch ports.
168 	 */
169 	for (i = 0; i < DSA_MAX_PORTS; i++) {
170 		struct net_device *slave_dev;
171 
172 		if (!(ds->phys_port_mask & (1 << i)))
173 			continue;
174 
175 		slave_dev = dsa_slave_create(ds, parent, i, pd->port_names[i]);
176 		if (slave_dev == NULL) {
177 			printk(KERN_ERR "%s[%d]: can't create dsa "
178 			       "slave device for port %d(%s)\n",
179 			       dst->master_netdev->name,
180 			       index, i, pd->port_names[i]);
181 			continue;
182 		}
183 
184 		ds->ports[i] = slave_dev;
185 	}
186 
187 	return ds;
188 
189 out_free:
190 	mdiobus_free(ds->slave_mii_bus);
191 out:
192 	kfree(ds);
193 	return ERR_PTR(ret);
194 }
195 
196 static void dsa_switch_destroy(struct dsa_switch *ds)
197 {
198 }
199 
200 
201 /* hooks for ethertype-less tagging formats *********************************/
202 /*
203  * The original DSA tag format and some other tag formats have no
204  * ethertype, which means that we need to add a little hack to the
205  * networking receive path to make sure that received frames get
206  * the right ->protocol assigned to them when one of those tag
207  * formats is in use.
208  */
209 bool dsa_uses_dsa_tags(void *dsa_ptr)
210 {
211 	struct dsa_switch_tree *dst = dsa_ptr;
212 
213 	return !!(dst->tag_protocol == htons(ETH_P_DSA));
214 }
215 
216 bool dsa_uses_trailer_tags(void *dsa_ptr)
217 {
218 	struct dsa_switch_tree *dst = dsa_ptr;
219 
220 	return !!(dst->tag_protocol == htons(ETH_P_TRAILER));
221 }
222 
223 
224 /* link polling *************************************************************/
225 static void dsa_link_poll_work(struct work_struct *ugly)
226 {
227 	struct dsa_switch_tree *dst;
228 	int i;
229 
230 	dst = container_of(ugly, struct dsa_switch_tree, link_poll_work);
231 
232 	for (i = 0; i < dst->pd->nr_chips; i++) {
233 		struct dsa_switch *ds = dst->ds[i];
234 
235 		if (ds != NULL && ds->drv->poll_link != NULL)
236 			ds->drv->poll_link(ds);
237 	}
238 
239 	mod_timer(&dst->link_poll_timer, round_jiffies(jiffies + HZ));
240 }
241 
242 static void dsa_link_poll_timer(unsigned long _dst)
243 {
244 	struct dsa_switch_tree *dst = (void *)_dst;
245 
246 	schedule_work(&dst->link_poll_work);
247 }
248 
249 
250 /* platform driver init and cleanup *****************************************/
251 static int dev_is_class(struct device *dev, void *class)
252 {
253 	if (dev->class != NULL && !strcmp(dev->class->name, class))
254 		return 1;
255 
256 	return 0;
257 }
258 
259 static struct device *dev_find_class(struct device *parent, char *class)
260 {
261 	if (dev_is_class(parent, class)) {
262 		get_device(parent);
263 		return parent;
264 	}
265 
266 	return device_find_child(parent, class, dev_is_class);
267 }
268 
269 static struct mii_bus *dev_to_mii_bus(struct device *dev)
270 {
271 	struct device *d;
272 
273 	d = dev_find_class(dev, "mdio_bus");
274 	if (d != NULL) {
275 		struct mii_bus *bus;
276 
277 		bus = to_mii_bus(d);
278 		put_device(d);
279 
280 		return bus;
281 	}
282 
283 	return NULL;
284 }
285 
286 static struct net_device *dev_to_net_device(struct device *dev)
287 {
288 	struct device *d;
289 
290 	d = dev_find_class(dev, "net");
291 	if (d != NULL) {
292 		struct net_device *nd;
293 
294 		nd = to_net_dev(d);
295 		dev_hold(nd);
296 		put_device(d);
297 
298 		return nd;
299 	}
300 
301 	return NULL;
302 }
303 
304 static int dsa_probe(struct platform_device *pdev)
305 {
306 	static int dsa_version_printed;
307 	struct dsa_platform_data *pd = pdev->dev.platform_data;
308 	struct net_device *dev;
309 	struct dsa_switch_tree *dst;
310 	int i;
311 
312 	if (!dsa_version_printed++)
313 		printk(KERN_NOTICE "Distributed Switch Architecture "
314 			"driver version %s\n", dsa_driver_version);
315 
316 	if (pd == NULL || pd->netdev == NULL)
317 		return -EINVAL;
318 
319 	dev = dev_to_net_device(pd->netdev);
320 	if (dev == NULL)
321 		return -EINVAL;
322 
323 	if (dev->dsa_ptr != NULL) {
324 		dev_put(dev);
325 		return -EEXIST;
326 	}
327 
328 	dst = kzalloc(sizeof(*dst), GFP_KERNEL);
329 	if (dst == NULL) {
330 		dev_put(dev);
331 		return -ENOMEM;
332 	}
333 
334 	platform_set_drvdata(pdev, dst);
335 
336 	dst->pd = pd;
337 	dst->master_netdev = dev;
338 	dst->cpu_switch = -1;
339 	dst->cpu_port = -1;
340 
341 	for (i = 0; i < pd->nr_chips; i++) {
342 		struct mii_bus *bus;
343 		struct dsa_switch *ds;
344 
345 		bus = dev_to_mii_bus(pd->chip[i].mii_bus);
346 		if (bus == NULL) {
347 			printk(KERN_ERR "%s[%d]: no mii bus found for "
348 				"dsa switch\n", dev->name, i);
349 			continue;
350 		}
351 
352 		ds = dsa_switch_setup(dst, i, &pdev->dev, bus);
353 		if (IS_ERR(ds)) {
354 			printk(KERN_ERR "%s[%d]: couldn't create dsa switch "
355 				"instance (error %ld)\n", dev->name, i,
356 				PTR_ERR(ds));
357 			continue;
358 		}
359 
360 		dst->ds[i] = ds;
361 		if (ds->drv->poll_link != NULL)
362 			dst->link_poll_needed = 1;
363 	}
364 
365 	/*
366 	 * If we use a tagging format that doesn't have an ethertype
367 	 * field, make sure that all packets from this point on get
368 	 * sent to the tag format's receive function.
369 	 */
370 	wmb();
371 	dev->dsa_ptr = (void *)dst;
372 
373 	if (dst->link_poll_needed) {
374 		INIT_WORK(&dst->link_poll_work, dsa_link_poll_work);
375 		init_timer(&dst->link_poll_timer);
376 		dst->link_poll_timer.data = (unsigned long)dst;
377 		dst->link_poll_timer.function = dsa_link_poll_timer;
378 		dst->link_poll_timer.expires = round_jiffies(jiffies + HZ);
379 		add_timer(&dst->link_poll_timer);
380 	}
381 
382 	return 0;
383 }
384 
385 static int dsa_remove(struct platform_device *pdev)
386 {
387 	struct dsa_switch_tree *dst = platform_get_drvdata(pdev);
388 	int i;
389 
390 	if (dst->link_poll_needed)
391 		del_timer_sync(&dst->link_poll_timer);
392 
393 	flush_scheduled_work();
394 
395 	for (i = 0; i < dst->pd->nr_chips; i++) {
396 		struct dsa_switch *ds = dst->ds[i];
397 
398 		if (ds != NULL)
399 			dsa_switch_destroy(ds);
400 	}
401 
402 	return 0;
403 }
404 
405 static void dsa_shutdown(struct platform_device *pdev)
406 {
407 }
408 
409 static struct platform_driver dsa_driver = {
410 	.probe		= dsa_probe,
411 	.remove		= dsa_remove,
412 	.shutdown	= dsa_shutdown,
413 	.driver = {
414 		.name	= "dsa",
415 		.owner	= THIS_MODULE,
416 	},
417 };
418 
419 static int __init dsa_init_module(void)
420 {
421 	return platform_driver_register(&dsa_driver);
422 }
423 module_init(dsa_init_module);
424 
425 static void __exit dsa_cleanup_module(void)
426 {
427 	platform_driver_unregister(&dsa_driver);
428 }
429 module_exit(dsa_cleanup_module);
430 
431 MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>")
432 MODULE_DESCRIPTION("Driver for Distributed Switch Architecture switch chips");
433 MODULE_LICENSE("GPL");
434 MODULE_ALIAS("platform:dsa");
435