xref: /linux/drivers/hsi/clients/ssi_protocol.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
1 /*
2  * ssi_protocol.c
3  *
4  * Implementation of the SSI McSAAB improved protocol.
5  *
6  * Copyright (C) 2010 Nokia Corporation. All rights reserved.
7  * Copyright (C) 2013 Sebastian Reichel <sre@kernel.org>
8  *
9  * Contact: Carlos Chinea <carlos.chinea@nokia.com>
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License
13  * version 2 as published by the Free Software Foundation.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23  * 02110-1301 USA
24  */
25 
26 #include <linux/atomic.h>
27 #include <linux/clk.h>
28 #include <linux/device.h>
29 #include <linux/err.h>
30 #include <linux/gpio.h>
31 #include <linux/if_ether.h>
32 #include <linux/if_arp.h>
33 #include <linux/if_phonet.h>
34 #include <linux/init.h>
35 #include <linux/irq.h>
36 #include <linux/list.h>
37 #include <linux/module.h>
38 #include <linux/netdevice.h>
39 #include <linux/notifier.h>
40 #include <linux/scatterlist.h>
41 #include <linux/skbuff.h>
42 #include <linux/slab.h>
43 #include <linux/spinlock.h>
44 #include <linux/timer.h>
45 #include <linux/hsi/hsi.h>
46 #include <linux/hsi/ssi_protocol.h>
47 
48 void ssi_waketest(struct hsi_client *cl, unsigned int enable);
49 
50 #define SSIP_TXQUEUE_LEN	100
51 #define SSIP_MAX_MTU		65535
52 #define SSIP_DEFAULT_MTU	4000
53 #define PN_MEDIA_SOS		21
54 #define SSIP_MIN_PN_HDR		6	/* FIXME: Revisit */
55 #define SSIP_WDTOUT		2000	/* FIXME: has to be 500 msecs */
56 #define SSIP_KATOUT		15	/* 15 msecs */
57 #define SSIP_MAX_CMDS		5 /* Number of pre-allocated commands buffers */
58 #define SSIP_BYTES_TO_FRAMES(x) ((((x) - 1) >> 2) + 1)
59 #define SSIP_CMT_LOADER_SYNC	0x11223344
60 /*
61  * SSI protocol command definitions
62  */
63 #define SSIP_COMMAND(data)	((data) >> 28)
64 #define SSIP_PAYLOAD(data)	((data) & 0xfffffff)
65 /* Commands */
66 #define SSIP_SW_BREAK		0
67 #define SSIP_BOOTINFO_REQ	1
68 #define SSIP_BOOTINFO_RESP	2
69 #define SSIP_WAKETEST_RESULT	3
70 #define SSIP_START_TRANS	4
71 #define SSIP_READY		5
72 /* Payloads */
73 #define SSIP_DATA_VERSION(data)	((data) & 0xff)
74 #define SSIP_LOCAL_VERID	1
75 #define SSIP_WAKETEST_OK	0
76 #define SSIP_WAKETEST_FAILED	1
77 #define SSIP_PDU_LENGTH(data)	(((data) >> 8) & 0xffff)
78 #define SSIP_MSG_ID(data)	((data) & 0xff)
79 /* Generic Command */
80 #define SSIP_CMD(cmd, payload)	(((cmd) << 28) | ((payload) & 0xfffffff))
81 /* Commands for the control channel */
82 #define SSIP_BOOTINFO_REQ_CMD(ver) \
83 		SSIP_CMD(SSIP_BOOTINFO_REQ, SSIP_DATA_VERSION(ver))
84 #define SSIP_BOOTINFO_RESP_CMD(ver) \
85 		SSIP_CMD(SSIP_BOOTINFO_RESP, SSIP_DATA_VERSION(ver))
86 #define SSIP_START_TRANS_CMD(pdulen, id) \
87 		SSIP_CMD(SSIP_START_TRANS, (((pdulen) << 8) | SSIP_MSG_ID(id)))
88 #define SSIP_READY_CMD		SSIP_CMD(SSIP_READY, 0)
89 #define SSIP_SWBREAK_CMD	SSIP_CMD(SSIP_SW_BREAK, 0)
90 
91 /* Main state machine states */
92 enum {
93 	INIT,
94 	HANDSHAKE,
95 	ACTIVE,
96 };
97 
98 /* Send state machine states */
99 enum {
100 	SEND_IDLE,
101 	WAIT4READY,
102 	SEND_READY,
103 	SENDING,
104 	SENDING_SWBREAK,
105 };
106 
107 /* Receive state machine states */
108 enum {
109 	RECV_IDLE,
110 	RECV_READY,
111 	RECEIVING,
112 };
113 
114 /**
115  * struct ssi_protocol - SSI protocol (McSAAB) data
116  * @main_state: Main state machine
117  * @send_state: TX state machine
118  * @recv_state: RX state machine
119  * @waketest: Flag to follow wake line test
120  * @rxid: RX data id
121  * @txid: TX data id
122  * @txqueue_len: TX queue length
123  * @tx_wd: TX watchdog
124  * @rx_wd: RX watchdog
125  * @keep_alive: Workaround for SSI HW bug
126  * @lock: To serialize access to this struct
127  * @netdev: Phonet network device
128  * @txqueue: TX data queue
129  * @cmdqueue: Queue of free commands
130  * @cl: HSI client own reference
131  * @link: Link for ssip_list
132  * @tx_usecount: Refcount to keep track the slaves that use the wake line
133  * @channel_id_cmd: HSI channel id for command stream
134  * @channel_id_data: HSI channel id for data stream
135  */
136 struct ssi_protocol {
137 	unsigned int		main_state;
138 	unsigned int		send_state;
139 	unsigned int		recv_state;
140 	unsigned int		waketest:1;
141 	u8			rxid;
142 	u8			txid;
143 	unsigned int		txqueue_len;
144 	struct timer_list	tx_wd;
145 	struct timer_list	rx_wd;
146 	struct timer_list	keep_alive; /* wake-up workaround */
147 	spinlock_t		lock;
148 	struct net_device	*netdev;
149 	struct list_head	txqueue;
150 	struct list_head	cmdqueue;
151 	struct hsi_client	*cl;
152 	struct list_head	link;
153 	atomic_t		tx_usecnt;
154 	int			channel_id_cmd;
155 	int			channel_id_data;
156 };
157 
158 /* List of ssi protocol instances */
159 static LIST_HEAD(ssip_list);
160 
161 static void ssip_rxcmd_complete(struct hsi_msg *msg);
162 
163 static inline void ssip_set_cmd(struct hsi_msg *msg, u32 cmd)
164 {
165 	u32 *data;
166 
167 	data = sg_virt(msg->sgt.sgl);
168 	*data = cmd;
169 }
170 
171 static inline u32 ssip_get_cmd(struct hsi_msg *msg)
172 {
173 	u32 *data;
174 
175 	data = sg_virt(msg->sgt.sgl);
176 
177 	return *data;
178 }
179 
180 static void ssip_skb_to_msg(struct sk_buff *skb, struct hsi_msg *msg)
181 {
182 	skb_frag_t *frag;
183 	struct scatterlist *sg;
184 	int i;
185 
186 	BUG_ON(msg->sgt.nents != (unsigned int)(skb_shinfo(skb)->nr_frags + 1));
187 
188 	sg = msg->sgt.sgl;
189 	sg_set_buf(sg, skb->data, skb_headlen(skb));
190 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
191 		sg = sg_next(sg);
192 		BUG_ON(!sg);
193 		frag = &skb_shinfo(skb)->frags[i];
194 		sg_set_page(sg, frag->page.p, frag->size, frag->page_offset);
195 	}
196 }
197 
198 static void ssip_free_data(struct hsi_msg *msg)
199 {
200 	struct sk_buff *skb;
201 
202 	skb = msg->context;
203 	pr_debug("free data: msg %p context %p skb %p\n", msg, msg->context,
204 								skb);
205 	msg->destructor = NULL;
206 	dev_kfree_skb(skb);
207 	hsi_free_msg(msg);
208 }
209 
210 static struct hsi_msg *ssip_alloc_data(struct ssi_protocol *ssi,
211 					struct sk_buff *skb, gfp_t flags)
212 {
213 	struct hsi_msg *msg;
214 
215 	msg = hsi_alloc_msg(skb_shinfo(skb)->nr_frags + 1, flags);
216 	if (!msg)
217 		return NULL;
218 	ssip_skb_to_msg(skb, msg);
219 	msg->destructor = ssip_free_data;
220 	msg->channel = ssi->channel_id_data;
221 	msg->context = skb;
222 
223 	return msg;
224 }
225 
226 static inline void ssip_release_cmd(struct hsi_msg *msg)
227 {
228 	struct ssi_protocol *ssi = hsi_client_drvdata(msg->cl);
229 
230 	dev_dbg(&msg->cl->device, "Release cmd 0x%08x\n", ssip_get_cmd(msg));
231 	spin_lock_bh(&ssi->lock);
232 	list_add_tail(&msg->link, &ssi->cmdqueue);
233 	spin_unlock_bh(&ssi->lock);
234 }
235 
236 static struct hsi_msg *ssip_claim_cmd(struct ssi_protocol *ssi)
237 {
238 	struct hsi_msg *msg;
239 
240 	BUG_ON(list_empty(&ssi->cmdqueue));
241 
242 	spin_lock_bh(&ssi->lock);
243 	msg = list_first_entry(&ssi->cmdqueue, struct hsi_msg, link);
244 	list_del(&msg->link);
245 	spin_unlock_bh(&ssi->lock);
246 	msg->destructor = ssip_release_cmd;
247 
248 	return msg;
249 }
250 
251 static void ssip_free_cmds(struct ssi_protocol *ssi)
252 {
253 	struct hsi_msg *msg, *tmp;
254 
255 	list_for_each_entry_safe(msg, tmp, &ssi->cmdqueue, link) {
256 		list_del(&msg->link);
257 		msg->destructor = NULL;
258 		kfree(sg_virt(msg->sgt.sgl));
259 		hsi_free_msg(msg);
260 	}
261 }
262 
263 static int ssip_alloc_cmds(struct ssi_protocol *ssi)
264 {
265 	struct hsi_msg *msg;
266 	u32 *buf;
267 	unsigned int i;
268 
269 	for (i = 0; i < SSIP_MAX_CMDS; i++) {
270 		msg = hsi_alloc_msg(1, GFP_KERNEL);
271 		if (!msg)
272 			goto out;
273 		buf = kmalloc(sizeof(*buf), GFP_KERNEL);
274 		if (!buf) {
275 			hsi_free_msg(msg);
276 			goto out;
277 		}
278 		sg_init_one(msg->sgt.sgl, buf, sizeof(*buf));
279 		msg->channel = ssi->channel_id_cmd;
280 		list_add_tail(&msg->link, &ssi->cmdqueue);
281 	}
282 
283 	return 0;
284 out:
285 	ssip_free_cmds(ssi);
286 
287 	return -ENOMEM;
288 }
289 
290 static void ssip_set_rxstate(struct ssi_protocol *ssi, unsigned int state)
291 {
292 	ssi->recv_state = state;
293 	switch (state) {
294 	case RECV_IDLE:
295 		del_timer(&ssi->rx_wd);
296 		if (ssi->send_state == SEND_IDLE)
297 			del_timer(&ssi->keep_alive);
298 		break;
299 	case RECV_READY:
300 		/* CMT speech workaround */
301 		if (atomic_read(&ssi->tx_usecnt))
302 			break;
303 		/* Otherwise fall through */
304 	case RECEIVING:
305 		mod_timer(&ssi->keep_alive, jiffies +
306 						msecs_to_jiffies(SSIP_KATOUT));
307 		mod_timer(&ssi->rx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
308 		break;
309 	default:
310 		break;
311 	}
312 }
313 
314 static void ssip_set_txstate(struct ssi_protocol *ssi, unsigned int state)
315 {
316 	ssi->send_state = state;
317 	switch (state) {
318 	case SEND_IDLE:
319 	case SEND_READY:
320 		del_timer(&ssi->tx_wd);
321 		if (ssi->recv_state == RECV_IDLE)
322 			del_timer(&ssi->keep_alive);
323 		break;
324 	case WAIT4READY:
325 	case SENDING:
326 	case SENDING_SWBREAK:
327 		mod_timer(&ssi->keep_alive,
328 				jiffies + msecs_to_jiffies(SSIP_KATOUT));
329 		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
330 		break;
331 	default:
332 		break;
333 	}
334 }
335 
336 struct hsi_client *ssip_slave_get_master(struct hsi_client *slave)
337 {
338 	struct hsi_client *master = ERR_PTR(-ENODEV);
339 	struct ssi_protocol *ssi;
340 
341 	list_for_each_entry(ssi, &ssip_list, link)
342 		if (slave->device.parent == ssi->cl->device.parent) {
343 			master = ssi->cl;
344 			break;
345 		}
346 
347 	return master;
348 }
349 EXPORT_SYMBOL_GPL(ssip_slave_get_master);
350 
351 int ssip_slave_start_tx(struct hsi_client *master)
352 {
353 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
354 
355 	dev_dbg(&master->device, "start TX %d\n", atomic_read(&ssi->tx_usecnt));
356 	spin_lock_bh(&ssi->lock);
357 	if (ssi->send_state == SEND_IDLE) {
358 		ssip_set_txstate(ssi, WAIT4READY);
359 		hsi_start_tx(master);
360 	}
361 	spin_unlock_bh(&ssi->lock);
362 	atomic_inc(&ssi->tx_usecnt);
363 
364 	return 0;
365 }
366 EXPORT_SYMBOL_GPL(ssip_slave_start_tx);
367 
368 int ssip_slave_stop_tx(struct hsi_client *master)
369 {
370 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
371 
372 	WARN_ON_ONCE(atomic_read(&ssi->tx_usecnt) == 0);
373 
374 	if (atomic_dec_and_test(&ssi->tx_usecnt)) {
375 		spin_lock_bh(&ssi->lock);
376 		if ((ssi->send_state == SEND_READY) ||
377 			(ssi->send_state == WAIT4READY)) {
378 			ssip_set_txstate(ssi, SEND_IDLE);
379 			hsi_stop_tx(master);
380 		}
381 		spin_unlock_bh(&ssi->lock);
382 	}
383 	dev_dbg(&master->device, "stop TX %d\n", atomic_read(&ssi->tx_usecnt));
384 
385 	return 0;
386 }
387 EXPORT_SYMBOL_GPL(ssip_slave_stop_tx);
388 
389 int ssip_slave_running(struct hsi_client *master)
390 {
391 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
392 	return netif_running(ssi->netdev);
393 }
394 EXPORT_SYMBOL_GPL(ssip_slave_running);
395 
396 static void ssip_reset(struct hsi_client *cl)
397 {
398 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
399 	struct list_head *head, *tmp;
400 	struct hsi_msg *msg;
401 
402 	if (netif_running(ssi->netdev))
403 		netif_carrier_off(ssi->netdev);
404 	hsi_flush(cl);
405 	spin_lock_bh(&ssi->lock);
406 	if (ssi->send_state != SEND_IDLE)
407 		hsi_stop_tx(cl);
408 	if (ssi->waketest)
409 		ssi_waketest(cl, 0);
410 	del_timer(&ssi->rx_wd);
411 	del_timer(&ssi->tx_wd);
412 	del_timer(&ssi->keep_alive);
413 	ssi->main_state = 0;
414 	ssi->send_state = 0;
415 	ssi->recv_state = 0;
416 	ssi->waketest = 0;
417 	ssi->rxid = 0;
418 	ssi->txid = 0;
419 	list_for_each_safe(head, tmp, &ssi->txqueue) {
420 		msg = list_entry(head, struct hsi_msg, link);
421 		dev_dbg(&cl->device, "Pending TX data\n");
422 		list_del(head);
423 		ssip_free_data(msg);
424 	}
425 	ssi->txqueue_len = 0;
426 	spin_unlock_bh(&ssi->lock);
427 }
428 
429 static void ssip_dump_state(struct hsi_client *cl)
430 {
431 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
432 	struct hsi_msg *msg;
433 
434 	spin_lock_bh(&ssi->lock);
435 	dev_err(&cl->device, "Main state: %d\n", ssi->main_state);
436 	dev_err(&cl->device, "Recv state: %d\n", ssi->recv_state);
437 	dev_err(&cl->device, "Send state: %d\n", ssi->send_state);
438 	dev_err(&cl->device, "CMT %s\n", (ssi->main_state == ACTIVE) ?
439 							"Online" : "Offline");
440 	dev_err(&cl->device, "Wake test %d\n", ssi->waketest);
441 	dev_err(&cl->device, "Data RX id: %d\n", ssi->rxid);
442 	dev_err(&cl->device, "Data TX id: %d\n", ssi->txid);
443 
444 	list_for_each_entry(msg, &ssi->txqueue, link)
445 		dev_err(&cl->device, "pending TX data (%p)\n", msg);
446 	spin_unlock_bh(&ssi->lock);
447 }
448 
449 static void ssip_error(struct hsi_client *cl)
450 {
451 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
452 	struct hsi_msg *msg;
453 
454 	ssip_dump_state(cl);
455 	ssip_reset(cl);
456 	msg = ssip_claim_cmd(ssi);
457 	msg->complete = ssip_rxcmd_complete;
458 	hsi_async_read(cl, msg);
459 }
460 
461 static void ssip_keep_alive(unsigned long data)
462 {
463 	struct hsi_client *cl = (struct hsi_client *)data;
464 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
465 
466 	dev_dbg(&cl->device, "Keep alive kick in: m(%d) r(%d) s(%d)\n",
467 		ssi->main_state, ssi->recv_state, ssi->send_state);
468 
469 	spin_lock(&ssi->lock);
470 	if (ssi->recv_state == RECV_IDLE)
471 		switch (ssi->send_state) {
472 		case SEND_READY:
473 			if (atomic_read(&ssi->tx_usecnt) == 0)
474 				break;
475 			/*
476 			 * Fall through. Workaround for cmt-speech
477 			 * in that case we relay on audio timers.
478 			 */
479 		case SEND_IDLE:
480 			spin_unlock(&ssi->lock);
481 			return;
482 		}
483 	mod_timer(&ssi->keep_alive, jiffies + msecs_to_jiffies(SSIP_KATOUT));
484 	spin_unlock(&ssi->lock);
485 }
486 
487 static void ssip_wd(unsigned long data)
488 {
489 	struct hsi_client *cl = (struct hsi_client *)data;
490 
491 	dev_err(&cl->device, "Watchdog trigerred\n");
492 	ssip_error(cl);
493 }
494 
495 static void ssip_send_bootinfo_req_cmd(struct hsi_client *cl)
496 {
497 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
498 	struct hsi_msg *msg;
499 
500 	dev_dbg(&cl->device, "Issuing BOOT INFO REQ command\n");
501 	msg = ssip_claim_cmd(ssi);
502 	ssip_set_cmd(msg, SSIP_BOOTINFO_REQ_CMD(SSIP_LOCAL_VERID));
503 	msg->complete = ssip_release_cmd;
504 	hsi_async_write(cl, msg);
505 	dev_dbg(&cl->device, "Issuing RX command\n");
506 	msg = ssip_claim_cmd(ssi);
507 	msg->complete = ssip_rxcmd_complete;
508 	hsi_async_read(cl, msg);
509 }
510 
511 static void ssip_start_rx(struct hsi_client *cl)
512 {
513 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
514 	struct hsi_msg *msg;
515 
516 	dev_dbg(&cl->device, "RX start M(%d) R(%d)\n", ssi->main_state,
517 						ssi->recv_state);
518 	spin_lock(&ssi->lock);
519 	/*
520 	 * We can have two UP events in a row due to a short low
521 	 * high transition. Therefore we need to ignore the sencond UP event.
522 	 */
523 	if ((ssi->main_state != ACTIVE) || (ssi->recv_state == RECV_READY)) {
524 		if (ssi->main_state == INIT) {
525 			ssi->main_state = HANDSHAKE;
526 			spin_unlock(&ssi->lock);
527 			ssip_send_bootinfo_req_cmd(cl);
528 		} else {
529 			spin_unlock(&ssi->lock);
530 		}
531 		return;
532 	}
533 	ssip_set_rxstate(ssi, RECV_READY);
534 	spin_unlock(&ssi->lock);
535 
536 	msg = ssip_claim_cmd(ssi);
537 	ssip_set_cmd(msg, SSIP_READY_CMD);
538 	msg->complete = ssip_release_cmd;
539 	dev_dbg(&cl->device, "Send READY\n");
540 	hsi_async_write(cl, msg);
541 }
542 
543 static void ssip_stop_rx(struct hsi_client *cl)
544 {
545 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
546 
547 	dev_dbg(&cl->device, "RX stop M(%d)\n", ssi->main_state);
548 	spin_lock(&ssi->lock);
549 	if (likely(ssi->main_state == ACTIVE))
550 		ssip_set_rxstate(ssi, RECV_IDLE);
551 	spin_unlock(&ssi->lock);
552 }
553 
554 static void ssip_free_strans(struct hsi_msg *msg)
555 {
556 	ssip_free_data(msg->context);
557 	ssip_release_cmd(msg);
558 }
559 
560 static void ssip_strans_complete(struct hsi_msg *msg)
561 {
562 	struct hsi_client *cl = msg->cl;
563 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
564 	struct hsi_msg *data;
565 
566 	data = msg->context;
567 	ssip_release_cmd(msg);
568 	spin_lock(&ssi->lock);
569 	ssip_set_txstate(ssi, SENDING);
570 	spin_unlock(&ssi->lock);
571 	hsi_async_write(cl, data);
572 }
573 
574 static int ssip_xmit(struct hsi_client *cl)
575 {
576 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
577 	struct hsi_msg *msg, *dmsg;
578 	struct sk_buff *skb;
579 
580 	spin_lock_bh(&ssi->lock);
581 	if (list_empty(&ssi->txqueue)) {
582 		spin_unlock_bh(&ssi->lock);
583 		return 0;
584 	}
585 	dmsg = list_first_entry(&ssi->txqueue, struct hsi_msg, link);
586 	list_del(&dmsg->link);
587 	ssi->txqueue_len--;
588 	spin_unlock_bh(&ssi->lock);
589 
590 	msg = ssip_claim_cmd(ssi);
591 	skb = dmsg->context;
592 	msg->context = dmsg;
593 	msg->complete = ssip_strans_complete;
594 	msg->destructor = ssip_free_strans;
595 
596 	spin_lock_bh(&ssi->lock);
597 	ssip_set_cmd(msg, SSIP_START_TRANS_CMD(SSIP_BYTES_TO_FRAMES(skb->len),
598 								ssi->txid));
599 	ssi->txid++;
600 	ssip_set_txstate(ssi, SENDING);
601 	spin_unlock_bh(&ssi->lock);
602 
603 	dev_dbg(&cl->device, "Send STRANS (%d frames)\n",
604 						SSIP_BYTES_TO_FRAMES(skb->len));
605 
606 	return hsi_async_write(cl, msg);
607 }
608 
609 /* In soft IRQ context */
610 static void ssip_pn_rx(struct sk_buff *skb)
611 {
612 	struct net_device *dev = skb->dev;
613 
614 	if (unlikely(!netif_running(dev))) {
615 		dev_dbg(&dev->dev, "Drop RX packet\n");
616 		dev->stats.rx_dropped++;
617 		dev_kfree_skb(skb);
618 		return;
619 	}
620 	if (unlikely(!pskb_may_pull(skb, SSIP_MIN_PN_HDR))) {
621 		dev_dbg(&dev->dev, "Error drop RX packet\n");
622 		dev->stats.rx_errors++;
623 		dev->stats.rx_length_errors++;
624 		dev_kfree_skb(skb);
625 		return;
626 	}
627 	dev->stats.rx_packets++;
628 	dev->stats.rx_bytes += skb->len;
629 
630 	/* length field is exchanged in network byte order */
631 	((u16 *)skb->data)[2] = ntohs(((u16 *)skb->data)[2]);
632 	dev_dbg(&dev->dev, "RX length fixed (%04x -> %u)\n",
633 			((u16 *)skb->data)[2], ntohs(((u16 *)skb->data)[2]));
634 
635 	skb->protocol = htons(ETH_P_PHONET);
636 	skb_reset_mac_header(skb);
637 	__skb_pull(skb, 1);
638 	netif_rx(skb);
639 }
640 
641 static void ssip_rx_data_complete(struct hsi_msg *msg)
642 {
643 	struct hsi_client *cl = msg->cl;
644 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
645 	struct sk_buff *skb;
646 
647 	if (msg->status == HSI_STATUS_ERROR) {
648 		dev_err(&cl->device, "RX data error\n");
649 		ssip_free_data(msg);
650 		ssip_error(cl);
651 		return;
652 	}
653 	del_timer(&ssi->rx_wd); /* FIXME: Revisit */
654 	skb = msg->context;
655 	ssip_pn_rx(skb);
656 	hsi_free_msg(msg);
657 }
658 
659 static void ssip_rx_bootinforeq(struct hsi_client *cl, u32 cmd)
660 {
661 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
662 	struct hsi_msg *msg;
663 
664 	/* Workaroud: Ignore CMT Loader message leftover */
665 	if (cmd == SSIP_CMT_LOADER_SYNC)
666 		return;
667 
668 	switch (ssi->main_state) {
669 	case ACTIVE:
670 		dev_err(&cl->device, "Boot info req on active state\n");
671 		ssip_error(cl);
672 		/* Fall through */
673 	case INIT:
674 		spin_lock(&ssi->lock);
675 		ssi->main_state = HANDSHAKE;
676 		if (!ssi->waketest) {
677 			ssi->waketest = 1;
678 			ssi_waketest(cl, 1); /* FIXME: To be removed */
679 		}
680 		/* Start boot handshake watchdog */
681 		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
682 		spin_unlock(&ssi->lock);
683 		dev_dbg(&cl->device, "Send BOOTINFO_RESP\n");
684 		if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
685 			dev_warn(&cl->device, "boot info req verid mismatch\n");
686 		msg = ssip_claim_cmd(ssi);
687 		ssip_set_cmd(msg, SSIP_BOOTINFO_RESP_CMD(SSIP_LOCAL_VERID));
688 		msg->complete = ssip_release_cmd;
689 		hsi_async_write(cl, msg);
690 		break;
691 	case HANDSHAKE:
692 		/* Ignore */
693 		break;
694 	default:
695 		dev_dbg(&cl->device, "Wrong state M(%d)\n", ssi->main_state);
696 		break;
697 	}
698 }
699 
700 static void ssip_rx_bootinforesp(struct hsi_client *cl, u32 cmd)
701 {
702 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
703 
704 	if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
705 		dev_warn(&cl->device, "boot info resp verid mismatch\n");
706 
707 	spin_lock(&ssi->lock);
708 	if (ssi->main_state != ACTIVE)
709 		/* Use tx_wd as a boot watchdog in non ACTIVE state */
710 		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
711 	else
712 		dev_dbg(&cl->device, "boot info resp ignored M(%d)\n",
713 							ssi->main_state);
714 	spin_unlock(&ssi->lock);
715 }
716 
717 static void ssip_rx_waketest(struct hsi_client *cl, u32 cmd)
718 {
719 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
720 	unsigned int wkres = SSIP_PAYLOAD(cmd);
721 
722 	spin_lock(&ssi->lock);
723 	if (ssi->main_state != HANDSHAKE) {
724 		dev_dbg(&cl->device, "wake lines test ignored M(%d)\n",
725 							ssi->main_state);
726 		spin_unlock(&ssi->lock);
727 		return;
728 	}
729 	if (ssi->waketest) {
730 		ssi->waketest = 0;
731 		ssi_waketest(cl, 0); /* FIXME: To be removed */
732 	}
733 	ssi->main_state = ACTIVE;
734 	del_timer(&ssi->tx_wd); /* Stop boot handshake timer */
735 	spin_unlock(&ssi->lock);
736 
737 	dev_notice(&cl->device, "WAKELINES TEST %s\n",
738 				wkres & SSIP_WAKETEST_FAILED ? "FAILED" : "OK");
739 	if (wkres & SSIP_WAKETEST_FAILED) {
740 		ssip_error(cl);
741 		return;
742 	}
743 	dev_dbg(&cl->device, "CMT is ONLINE\n");
744 	netif_wake_queue(ssi->netdev);
745 	netif_carrier_on(ssi->netdev);
746 }
747 
748 static void ssip_rx_ready(struct hsi_client *cl)
749 {
750 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
751 
752 	spin_lock(&ssi->lock);
753 	if (unlikely(ssi->main_state != ACTIVE)) {
754 		dev_dbg(&cl->device, "READY on wrong state: S(%d) M(%d)\n",
755 					ssi->send_state, ssi->main_state);
756 		spin_unlock(&ssi->lock);
757 		return;
758 	}
759 	if (ssi->send_state != WAIT4READY) {
760 		dev_dbg(&cl->device, "Ignore spurious READY command\n");
761 		spin_unlock(&ssi->lock);
762 		return;
763 	}
764 	ssip_set_txstate(ssi, SEND_READY);
765 	spin_unlock(&ssi->lock);
766 	ssip_xmit(cl);
767 }
768 
769 static void ssip_rx_strans(struct hsi_client *cl, u32 cmd)
770 {
771 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
772 	struct sk_buff *skb;
773 	struct hsi_msg *msg;
774 	int len = SSIP_PDU_LENGTH(cmd);
775 
776 	dev_dbg(&cl->device, "RX strans: %d frames\n", len);
777 	spin_lock(&ssi->lock);
778 	if (unlikely(ssi->main_state != ACTIVE)) {
779 		dev_err(&cl->device, "START TRANS wrong state: S(%d) M(%d)\n",
780 					ssi->send_state, ssi->main_state);
781 		spin_unlock(&ssi->lock);
782 		return;
783 	}
784 	ssip_set_rxstate(ssi, RECEIVING);
785 	if (unlikely(SSIP_MSG_ID(cmd) != ssi->rxid)) {
786 		dev_err(&cl->device, "START TRANS id %d expeceted %d\n",
787 					SSIP_MSG_ID(cmd), ssi->rxid);
788 		spin_unlock(&ssi->lock);
789 		goto out1;
790 	}
791 	ssi->rxid++;
792 	spin_unlock(&ssi->lock);
793 	skb = netdev_alloc_skb(ssi->netdev, len * 4);
794 	if (unlikely(!skb)) {
795 		dev_err(&cl->device, "No memory for rx skb\n");
796 		goto out1;
797 	}
798 	skb->dev = ssi->netdev;
799 	skb_put(skb, len * 4);
800 	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
801 	if (unlikely(!msg)) {
802 		dev_err(&cl->device, "No memory for RX data msg\n");
803 		goto out2;
804 	}
805 	msg->complete = ssip_rx_data_complete;
806 	hsi_async_read(cl, msg);
807 
808 	return;
809 out2:
810 	dev_kfree_skb(skb);
811 out1:
812 	ssip_error(cl);
813 }
814 
815 static void ssip_rxcmd_complete(struct hsi_msg *msg)
816 {
817 	struct hsi_client *cl = msg->cl;
818 	u32 cmd = ssip_get_cmd(msg);
819 	unsigned int cmdid = SSIP_COMMAND(cmd);
820 
821 	if (msg->status == HSI_STATUS_ERROR) {
822 		dev_err(&cl->device, "RX error detected\n");
823 		ssip_release_cmd(msg);
824 		ssip_error(cl);
825 		return;
826 	}
827 	hsi_async_read(cl, msg);
828 	dev_dbg(&cl->device, "RX cmd: 0x%08x\n", cmd);
829 	switch (cmdid) {
830 	case SSIP_SW_BREAK:
831 		/* Ignored */
832 		break;
833 	case SSIP_BOOTINFO_REQ:
834 		ssip_rx_bootinforeq(cl, cmd);
835 		break;
836 	case SSIP_BOOTINFO_RESP:
837 		ssip_rx_bootinforesp(cl, cmd);
838 		break;
839 	case SSIP_WAKETEST_RESULT:
840 		ssip_rx_waketest(cl, cmd);
841 		break;
842 	case SSIP_START_TRANS:
843 		ssip_rx_strans(cl, cmd);
844 		break;
845 	case SSIP_READY:
846 		ssip_rx_ready(cl);
847 		break;
848 	default:
849 		dev_warn(&cl->device, "command 0x%08x not supported\n", cmd);
850 		break;
851 	}
852 }
853 
854 static void ssip_swbreak_complete(struct hsi_msg *msg)
855 {
856 	struct hsi_client *cl = msg->cl;
857 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
858 
859 	ssip_release_cmd(msg);
860 	spin_lock(&ssi->lock);
861 	if (list_empty(&ssi->txqueue)) {
862 		if (atomic_read(&ssi->tx_usecnt)) {
863 			ssip_set_txstate(ssi, SEND_READY);
864 		} else {
865 			ssip_set_txstate(ssi, SEND_IDLE);
866 			hsi_stop_tx(cl);
867 		}
868 		spin_unlock(&ssi->lock);
869 	} else {
870 		spin_unlock(&ssi->lock);
871 		ssip_xmit(cl);
872 	}
873 	netif_wake_queue(ssi->netdev);
874 }
875 
876 static void ssip_tx_data_complete(struct hsi_msg *msg)
877 {
878 	struct hsi_client *cl = msg->cl;
879 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
880 	struct hsi_msg *cmsg;
881 
882 	if (msg->status == HSI_STATUS_ERROR) {
883 		dev_err(&cl->device, "TX data error\n");
884 		ssip_error(cl);
885 		goto out;
886 	}
887 	spin_lock(&ssi->lock);
888 	if (list_empty(&ssi->txqueue)) {
889 		ssip_set_txstate(ssi, SENDING_SWBREAK);
890 		spin_unlock(&ssi->lock);
891 		cmsg = ssip_claim_cmd(ssi);
892 		ssip_set_cmd(cmsg, SSIP_SWBREAK_CMD);
893 		cmsg->complete = ssip_swbreak_complete;
894 		dev_dbg(&cl->device, "Send SWBREAK\n");
895 		hsi_async_write(cl, cmsg);
896 	} else {
897 		spin_unlock(&ssi->lock);
898 		ssip_xmit(cl);
899 	}
900 out:
901 	ssip_free_data(msg);
902 }
903 
904 static void ssip_port_event(struct hsi_client *cl, unsigned long event)
905 {
906 	switch (event) {
907 	case HSI_EVENT_START_RX:
908 		ssip_start_rx(cl);
909 		break;
910 	case HSI_EVENT_STOP_RX:
911 		ssip_stop_rx(cl);
912 		break;
913 	default:
914 		return;
915 	}
916 }
917 
918 static int ssip_pn_open(struct net_device *dev)
919 {
920 	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
921 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
922 	int err;
923 
924 	err = hsi_claim_port(cl, 1);
925 	if (err < 0) {
926 		dev_err(&cl->device, "SSI port already claimed\n");
927 		return err;
928 	}
929 	err = hsi_register_port_event(cl, ssip_port_event);
930 	if (err < 0) {
931 		dev_err(&cl->device, "Register HSI port event failed (%d)\n",
932 			err);
933 		return err;
934 	}
935 	dev_dbg(&cl->device, "Configuring SSI port\n");
936 	hsi_setup(cl);
937 	spin_lock_bh(&ssi->lock);
938 	if (!ssi->waketest) {
939 		ssi->waketest = 1;
940 		ssi_waketest(cl, 1); /* FIXME: To be removed */
941 	}
942 	ssi->main_state = INIT;
943 	spin_unlock_bh(&ssi->lock);
944 
945 	return 0;
946 }
947 
948 static int ssip_pn_stop(struct net_device *dev)
949 {
950 	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
951 
952 	ssip_reset(cl);
953 	hsi_unregister_port_event(cl);
954 	hsi_release_port(cl);
955 
956 	return 0;
957 }
958 
959 static int ssip_pn_set_mtu(struct net_device *dev, int new_mtu)
960 {
961 	if (new_mtu > SSIP_MAX_MTU || new_mtu < PHONET_MIN_MTU)
962 		return -EINVAL;
963 	dev->mtu = new_mtu;
964 
965 	return 0;
966 }
967 
968 static int ssip_pn_xmit(struct sk_buff *skb, struct net_device *dev)
969 {
970 	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
971 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
972 	struct hsi_msg *msg;
973 
974 	if ((skb->protocol != htons(ETH_P_PHONET)) ||
975 					(skb->len < SSIP_MIN_PN_HDR))
976 		goto drop;
977 	/* Pad to 32-bits - FIXME: Revisit*/
978 	if ((skb->len & 3) && skb_pad(skb, 4 - (skb->len & 3)))
979 		goto drop;
980 
981 	/*
982 	 * Modem sends Phonet messages over SSI with its own endianess...
983 	 * Assume that modem has the same endianess as we do.
984 	 */
985 	if (skb_cow_head(skb, 0))
986 		goto drop;
987 
988 	/* length field is exchanged in network byte order */
989 	((u16 *)skb->data)[2] = htons(((u16 *)skb->data)[2]);
990 
991 	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
992 	if (!msg) {
993 		dev_dbg(&cl->device, "Dropping tx data: No memory\n");
994 		goto drop;
995 	}
996 	msg->complete = ssip_tx_data_complete;
997 
998 	spin_lock_bh(&ssi->lock);
999 	if (unlikely(ssi->main_state != ACTIVE)) {
1000 		spin_unlock_bh(&ssi->lock);
1001 		dev_dbg(&cl->device, "Dropping tx data: CMT is OFFLINE\n");
1002 		goto drop2;
1003 	}
1004 	list_add_tail(&msg->link, &ssi->txqueue);
1005 	ssi->txqueue_len++;
1006 	if (dev->tx_queue_len < ssi->txqueue_len) {
1007 		dev_info(&cl->device, "TX queue full %d\n", ssi->txqueue_len);
1008 		netif_stop_queue(dev);
1009 	}
1010 	if (ssi->send_state == SEND_IDLE) {
1011 		ssip_set_txstate(ssi, WAIT4READY);
1012 		spin_unlock_bh(&ssi->lock);
1013 		dev_dbg(&cl->device, "Start TX qlen %d\n", ssi->txqueue_len);
1014 		hsi_start_tx(cl);
1015 	} else if (ssi->send_state == SEND_READY) {
1016 		/* Needed for cmt-speech workaround */
1017 		dev_dbg(&cl->device, "Start TX on SEND READY qlen %d\n",
1018 							ssi->txqueue_len);
1019 		spin_unlock_bh(&ssi->lock);
1020 		ssip_xmit(cl);
1021 	} else {
1022 		spin_unlock_bh(&ssi->lock);
1023 	}
1024 	dev->stats.tx_packets++;
1025 	dev->stats.tx_bytes += skb->len;
1026 
1027 	return 0;
1028 drop2:
1029 	hsi_free_msg(msg);
1030 drop:
1031 	dev->stats.tx_dropped++;
1032 	dev_kfree_skb(skb);
1033 
1034 	return 0;
1035 }
1036 
1037 /* CMT reset event handler */
1038 void ssip_reset_event(struct hsi_client *master)
1039 {
1040 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
1041 	dev_err(&ssi->cl->device, "CMT reset detected!\n");
1042 	ssip_error(ssi->cl);
1043 }
1044 EXPORT_SYMBOL_GPL(ssip_reset_event);
1045 
1046 static const struct net_device_ops ssip_pn_ops = {
1047 	.ndo_open	= ssip_pn_open,
1048 	.ndo_stop	= ssip_pn_stop,
1049 	.ndo_start_xmit	= ssip_pn_xmit,
1050 	.ndo_change_mtu	= ssip_pn_set_mtu,
1051 };
1052 
1053 static void ssip_pn_setup(struct net_device *dev)
1054 {
1055 	dev->features		= 0;
1056 	dev->netdev_ops		= &ssip_pn_ops;
1057 	dev->type		= ARPHRD_PHONET;
1058 	dev->flags		= IFF_POINTOPOINT | IFF_NOARP;
1059 	dev->mtu		= SSIP_DEFAULT_MTU;
1060 	dev->hard_header_len	= 1;
1061 	dev->dev_addr[0]	= PN_MEDIA_SOS;
1062 	dev->addr_len		= 1;
1063 	dev->tx_queue_len	= SSIP_TXQUEUE_LEN;
1064 
1065 	dev->destructor		= free_netdev;
1066 	dev->header_ops		= &phonet_header_ops;
1067 }
1068 
1069 static int ssi_protocol_probe(struct device *dev)
1070 {
1071 	static const char ifname[] = "phonet%d";
1072 	struct hsi_client *cl = to_hsi_client(dev);
1073 	struct ssi_protocol *ssi;
1074 	int err;
1075 
1076 	ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
1077 	if (!ssi) {
1078 		dev_err(dev, "No memory for ssi protocol\n");
1079 		return -ENOMEM;
1080 	}
1081 
1082 	spin_lock_init(&ssi->lock);
1083 	init_timer_deferrable(&ssi->rx_wd);
1084 	init_timer_deferrable(&ssi->tx_wd);
1085 	init_timer(&ssi->keep_alive);
1086 	ssi->rx_wd.data = (unsigned long)cl;
1087 	ssi->rx_wd.function = ssip_wd;
1088 	ssi->tx_wd.data = (unsigned long)cl;
1089 	ssi->tx_wd.function = ssip_wd;
1090 	ssi->keep_alive.data = (unsigned long)cl;
1091 	ssi->keep_alive.function = ssip_keep_alive;
1092 	INIT_LIST_HEAD(&ssi->txqueue);
1093 	INIT_LIST_HEAD(&ssi->cmdqueue);
1094 	atomic_set(&ssi->tx_usecnt, 0);
1095 	hsi_client_set_drvdata(cl, ssi);
1096 	ssi->cl = cl;
1097 
1098 	ssi->channel_id_cmd = hsi_get_channel_id_by_name(cl, "mcsaab-control");
1099 	if (ssi->channel_id_cmd < 0) {
1100 		err = ssi->channel_id_cmd;
1101 		dev_err(dev, "Could not get cmd channel (%d)\n", err);
1102 		goto out;
1103 	}
1104 
1105 	ssi->channel_id_data = hsi_get_channel_id_by_name(cl, "mcsaab-data");
1106 	if (ssi->channel_id_data < 0) {
1107 		err = ssi->channel_id_data;
1108 		dev_err(dev, "Could not get data channel (%d)\n", err);
1109 		goto out;
1110 	}
1111 
1112 	err = ssip_alloc_cmds(ssi);
1113 	if (err < 0) {
1114 		dev_err(dev, "No memory for commands\n");
1115 		goto out;
1116 	}
1117 
1118 	ssi->netdev = alloc_netdev(0, ifname, NET_NAME_UNKNOWN, ssip_pn_setup);
1119 	if (!ssi->netdev) {
1120 		dev_err(dev, "No memory for netdev\n");
1121 		err = -ENOMEM;
1122 		goto out1;
1123 	}
1124 
1125 	SET_NETDEV_DEV(ssi->netdev, dev);
1126 	netif_carrier_off(ssi->netdev);
1127 	err = register_netdev(ssi->netdev);
1128 	if (err < 0) {
1129 		dev_err(dev, "Register netdev failed (%d)\n", err);
1130 		goto out2;
1131 	}
1132 
1133 	list_add(&ssi->link, &ssip_list);
1134 
1135 	dev_dbg(dev, "channel configuration: cmd=%d, data=%d\n",
1136 		ssi->channel_id_cmd, ssi->channel_id_data);
1137 
1138 	return 0;
1139 out2:
1140 	free_netdev(ssi->netdev);
1141 out1:
1142 	ssip_free_cmds(ssi);
1143 out:
1144 	kfree(ssi);
1145 
1146 	return err;
1147 }
1148 
1149 static int ssi_protocol_remove(struct device *dev)
1150 {
1151 	struct hsi_client *cl = to_hsi_client(dev);
1152 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
1153 
1154 	list_del(&ssi->link);
1155 	unregister_netdev(ssi->netdev);
1156 	ssip_free_cmds(ssi);
1157 	hsi_client_set_drvdata(cl, NULL);
1158 	kfree(ssi);
1159 
1160 	return 0;
1161 }
1162 
1163 static struct hsi_client_driver ssip_driver = {
1164 	.driver = {
1165 		.name	= "ssi-protocol",
1166 		.owner	= THIS_MODULE,
1167 		.probe	= ssi_protocol_probe,
1168 		.remove	= ssi_protocol_remove,
1169 	},
1170 };
1171 
1172 static int __init ssip_init(void)
1173 {
1174 	pr_info("SSI protocol aka McSAAB added\n");
1175 
1176 	return hsi_register_client_driver(&ssip_driver);
1177 }
1178 module_init(ssip_init);
1179 
1180 static void __exit ssip_exit(void)
1181 {
1182 	hsi_unregister_client_driver(&ssip_driver);
1183 	pr_info("SSI protocol driver removed\n");
1184 }
1185 module_exit(ssip_exit);
1186 
1187 MODULE_ALIAS("hsi:ssi-protocol");
1188 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
1189 MODULE_AUTHOR("Remi Denis-Courmont <remi.denis-courmont@nokia.com>");
1190 MODULE_DESCRIPTION("SSI protocol improved aka McSAAB");
1191 MODULE_LICENSE("GPL");
1192