xref: /openbmc/linux/drivers/w1/w1_netlink.c (revision f89735c4)
1 /*
2  * w1_netlink.c
3  *
4  * Copyright (c) 2003 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
5  *
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  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21 
22 #include <linux/skbuff.h>
23 #include <linux/netlink.h>
24 #include <linux/connector.h>
25 
26 #include "w1.h"
27 #include "w1_log.h"
28 #include "w1_netlink.h"
29 
30 #if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
31 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
32 {
33 	char buf[sizeof(struct cn_msg) + sizeof(struct w1_netlink_msg)];
34 	struct cn_msg *m = (struct cn_msg *)buf;
35 	struct w1_netlink_msg *w = (struct w1_netlink_msg *)(m+1);
36 
37 	memset(buf, 0, sizeof(buf));
38 
39 	m->id.idx = CN_W1_IDX;
40 	m->id.val = CN_W1_VAL;
41 
42 	m->seq = dev->seq++;
43 	m->len = sizeof(struct w1_netlink_msg);
44 
45 	memcpy(w, msg, sizeof(struct w1_netlink_msg));
46 
47 	cn_netlink_send(m, 0, GFP_KERNEL);
48 }
49 
50 static void w1_send_slave(struct w1_master *dev, u64 rn)
51 {
52 	struct cn_msg *msg = dev->priv;
53 	struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
54 	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
55 	int avail;
56 
57 	avail = dev->priv_size - cmd->len;
58 
59 	if (avail > 8) {
60 		u64 *data = (void *)(cmd + 1) + cmd->len;
61 
62 		*data = rn;
63 		cmd->len += 8;
64 		hdr->len += 8;
65 		msg->len += 8;
66 		return;
67 	}
68 
69 	msg->ack++;
70 	cn_netlink_send(msg, 0, GFP_KERNEL);
71 
72 	msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);
73 	hdr->len = sizeof(struct w1_netlink_cmd);
74 	cmd->len = 0;
75 }
76 
77 static int w1_process_search_command(struct w1_master *dev, struct cn_msg *msg,
78 		unsigned int avail)
79 {
80 	struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
81 	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
82 	int search_type = (cmd->cmd == W1_CMD_ALARM_SEARCH)?W1_ALARM_SEARCH:W1_SEARCH;
83 
84 	dev->priv = msg;
85 	dev->priv_size = avail;
86 
87 	w1_search_devices(dev, search_type, w1_send_slave);
88 
89 	msg->ack = 0;
90 	cn_netlink_send(msg, 0, GFP_KERNEL);
91 
92 	dev->priv = NULL;
93 	dev->priv_size = 0;
94 
95 	return 0;
96 }
97 
98 static int w1_send_read_reply(struct cn_msg *msg, struct w1_netlink_msg *hdr,
99 		struct w1_netlink_cmd *cmd)
100 {
101 	void *data;
102 	struct w1_netlink_msg *h;
103 	struct w1_netlink_cmd *c;
104 	struct cn_msg *cm;
105 	int err;
106 
107 	data = kzalloc(sizeof(struct cn_msg) +
108 			sizeof(struct w1_netlink_msg) +
109 			sizeof(struct w1_netlink_cmd) +
110 			cmd->len, GFP_KERNEL);
111 	if (!data)
112 		return -ENOMEM;
113 
114 	cm = (struct cn_msg *)(data);
115 	h = (struct w1_netlink_msg *)(cm + 1);
116 	c = (struct w1_netlink_cmd *)(h + 1);
117 
118 	memcpy(cm, msg, sizeof(struct cn_msg));
119 	memcpy(h, hdr, sizeof(struct w1_netlink_msg));
120 	memcpy(c, cmd, sizeof(struct w1_netlink_cmd));
121 
122 	cm->ack = msg->seq+1;
123 	cm->len = sizeof(struct w1_netlink_msg) +
124 		sizeof(struct w1_netlink_cmd) + cmd->len;
125 
126 	h->len = sizeof(struct w1_netlink_cmd) + cmd->len;
127 
128 	memcpy(c->data, cmd->data, c->len);
129 
130 	err = cn_netlink_send(cm, 0, GFP_KERNEL);
131 
132 	kfree(data);
133 
134 	return err;
135 }
136 
137 static int w1_process_command_io(struct w1_master *dev, struct cn_msg *msg,
138 		struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
139 {
140 	int err = 0;
141 
142 	switch (cmd->cmd) {
143 	case W1_CMD_TOUCH:
144 		w1_touch_block(dev, cmd->data, cmd->len);
145 		w1_send_read_reply(msg, hdr, cmd);
146 		break;
147 	case W1_CMD_READ:
148 		w1_read_block(dev, cmd->data, cmd->len);
149 		w1_send_read_reply(msg, hdr, cmd);
150 		break;
151 	case W1_CMD_WRITE:
152 		w1_write_block(dev, cmd->data, cmd->len);
153 		break;
154 	default:
155 		err = -1;
156 		break;
157 	}
158 
159 	return err;
160 }
161 
162 static int w1_process_command_master(struct w1_master *dev, struct cn_msg *req_msg,
163 		struct w1_netlink_msg *req_hdr, struct w1_netlink_cmd *req_cmd)
164 {
165 	int err = -EINVAL;
166 	struct cn_msg *msg;
167 	struct w1_netlink_msg *hdr;
168 	struct w1_netlink_cmd *cmd;
169 
170 	msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
171 	if (!msg)
172 		return -ENOMEM;
173 
174 	msg->id = req_msg->id;
175 	msg->seq = req_msg->seq;
176 	msg->ack = 0;
177 	msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);
178 
179 	hdr = (struct w1_netlink_msg *)(msg + 1);
180 	cmd = (struct w1_netlink_cmd *)(hdr + 1);
181 
182 	hdr->type = W1_MASTER_CMD;
183 	hdr->id = req_hdr->id;
184 	hdr->len = sizeof(struct w1_netlink_cmd);
185 
186 	cmd->cmd = req_cmd->cmd;
187 	cmd->len = 0;
188 
189 	switch (cmd->cmd) {
190 	case W1_CMD_SEARCH:
191 	case W1_CMD_ALARM_SEARCH:
192 		err = w1_process_search_command(dev, msg,
193 				PAGE_SIZE - msg->len - sizeof(struct cn_msg));
194 		break;
195 	case W1_CMD_READ:
196 	case W1_CMD_WRITE:
197 	case W1_CMD_TOUCH:
198 		err = w1_process_command_io(dev, msg, hdr, cmd);
199 		break;
200 	case W1_CMD_RESET:
201 		err = w1_reset_bus(dev);
202 		break;
203 	default:
204 		cmd->res = EINVAL;
205 		cn_netlink_send(msg, 0, GFP_KERNEL);
206 		break;
207 	}
208 
209 	kfree(msg);
210 	return err;
211 }
212 
213 static int w1_process_command_slave(struct w1_slave *sl, struct cn_msg *msg,
214 		struct w1_netlink_msg *hdr, struct w1_netlink_cmd *cmd)
215 {
216 	dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n",
217 		__func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
218 		sl->reg_num.crc, cmd->cmd, cmd->len);
219 
220 	return w1_process_command_io(sl->master, msg, hdr, cmd);
221 }
222 
223 static int w1_process_command_root(struct cn_msg *msg, struct w1_netlink_msg *mcmd)
224 {
225 	struct w1_master *m;
226 	struct cn_msg *cn;
227 	struct w1_netlink_msg *w;
228 	u32 *id;
229 
230 	if (mcmd->type != W1_LIST_MASTERS) {
231 		printk(KERN_NOTICE "%s: msg: %x.%x, wrong type: %u, len: %u.\n",
232 			__func__, msg->id.idx, msg->id.val, mcmd->type, mcmd->len);
233 		return -EPROTO;
234 	}
235 
236 	cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
237 	if (!cn)
238 		return -ENOMEM;
239 
240 	cn->id.idx = CN_W1_IDX;
241 	cn->id.val = CN_W1_VAL;
242 
243 	cn->seq = msg->seq;
244 	cn->ack = 1;
245 	cn->len = sizeof(struct w1_netlink_msg);
246 	w = (struct w1_netlink_msg *)(cn + 1);
247 
248 	w->type = W1_LIST_MASTERS;
249 	w->reserved = 0;
250 	w->len = 0;
251 	id = (u32 *)(w + 1);
252 
253 	mutex_lock(&w1_mlock);
254 	list_for_each_entry(m, &w1_masters, w1_master_entry) {
255 		if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
256 			cn_netlink_send(cn, 0, GFP_KERNEL);
257 			cn->ack++;
258 			cn->len = sizeof(struct w1_netlink_msg);
259 			w->len = 0;
260 			id = (u32 *)(w + 1);
261 		}
262 
263 		*id = m->id;
264 		w->len += sizeof(*id);
265 		cn->len += sizeof(*id);
266 		id++;
267 	}
268 	cn->ack = 0;
269 	cn_netlink_send(cn, 0, GFP_KERNEL);
270 	mutex_unlock(&w1_mlock);
271 
272 	kfree(cn);
273 	return 0;
274 }
275 
276 static void w1_cn_callback(void *data)
277 {
278 	struct cn_msg *msg = data;
279 	struct w1_netlink_msg *m = (struct w1_netlink_msg *)(msg + 1);
280 	struct w1_netlink_cmd *cmd;
281 	struct w1_slave *sl;
282 	struct w1_master *dev;
283 	int err = 0;
284 
285 	while (msg->len && !err) {
286 		struct w1_reg_num id;
287 		u16 mlen = m->len;
288 		u8 *cmd_data = m->data;
289 
290 		dev = NULL;
291 		sl = NULL;
292 
293 		memcpy(&id, m->id.id, sizeof(id));
294 #if 0
295 		printk("%s: %02x.%012llx.%02x: type=%02x, len=%u.\n",
296 				__func__, id.family, (unsigned long long)id.id, id.crc, m->type, m->len);
297 #endif
298 		if (m->len + sizeof(struct w1_netlink_msg) > msg->len) {
299 			err = -E2BIG;
300 			break;
301 		}
302 
303 		if (m->type == W1_MASTER_CMD) {
304 			dev = w1_search_master_id(m->id.mst.id);
305 		} else if (m->type == W1_SLAVE_CMD) {
306 			sl = w1_search_slave(&id);
307 			if (sl)
308 				dev = sl->master;
309 		} else {
310 			err = w1_process_command_root(msg, m);
311 			goto out_cont;
312 		}
313 
314 		if (!dev) {
315 			err = -ENODEV;
316 			goto out_cont;
317 		}
318 
319 		err = 0;
320 		if (!mlen)
321 			goto out_cont;
322 
323 		mutex_lock(&dev->mutex);
324 
325 		if (sl && w1_reset_select_slave(sl)) {
326 			err = -ENODEV;
327 			goto out_up;
328 		}
329 
330 		while (mlen) {
331 			cmd = (struct w1_netlink_cmd *)cmd_data;
332 
333 			if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
334 				err = -E2BIG;
335 				break;
336 			}
337 
338 			if (sl)
339 				w1_process_command_slave(sl, msg, m, cmd);
340 			else
341 				w1_process_command_master(dev, msg, m, cmd);
342 
343 			cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
344 			mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
345 		}
346 out_up:
347 		atomic_dec(&dev->refcnt);
348 		if (sl)
349 			atomic_dec(&sl->refcnt);
350 		mutex_unlock(&dev->mutex);
351 out_cont:
352 		msg->len -= sizeof(struct w1_netlink_msg) + m->len;
353 		m = (struct w1_netlink_msg *)(((u8 *)m) + sizeof(struct w1_netlink_msg) + m->len);
354 
355 		/*
356 		 * Let's allow requests for nonexisting devices.
357 		 */
358 		if (err == -ENODEV)
359 			err = 0;
360 	}
361 }
362 
363 int w1_init_netlink(void)
364 {
365 	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
366 
367 	return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
368 }
369 
370 void w1_fini_netlink(void)
371 {
372 	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
373 
374 	cn_del_callback(&w1_id);
375 }
376 #else
377 void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
378 {
379 }
380 
381 int w1_init_netlink(void)
382 {
383 	return 0;
384 }
385 
386 void w1_fini_netlink(void)
387 {
388 }
389 #endif
390