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 #define SSIP_WAKETEST_FLAG 0
92 
93 /* Main state machine states */
94 enum {
95 	INIT,
96 	HANDSHAKE,
97 	ACTIVE,
98 };
99 
100 /* Send state machine states */
101 enum {
102 	SEND_IDLE,
103 	WAIT4READY,
104 	SEND_READY,
105 	SENDING,
106 	SENDING_SWBREAK,
107 };
108 
109 /* Receive state machine states */
110 enum {
111 	RECV_IDLE,
112 	RECV_READY,
113 	RECEIVING,
114 };
115 
116 /**
117  * struct ssi_protocol - SSI protocol (McSAAB) data
118  * @main_state: Main state machine
119  * @send_state: TX state machine
120  * @recv_state: RX state machine
121  * @flags: Flags, currently only used to follow wake line test
122  * @rxid: RX data id
123  * @txid: TX data id
124  * @txqueue_len: TX queue length
125  * @tx_wd: TX watchdog
126  * @rx_wd: RX watchdog
127  * @keep_alive: Workaround for SSI HW bug
128  * @lock: To serialize access to this struct
129  * @netdev: Phonet network device
130  * @txqueue: TX data queue
131  * @cmdqueue: Queue of free commands
132  * @cl: HSI client own reference
133  * @link: Link for ssip_list
134  * @tx_usecount: Refcount to keep track the slaves that use the wake line
135  * @channel_id_cmd: HSI channel id for command stream
136  * @channel_id_data: HSI channel id for data stream
137  */
138 struct ssi_protocol {
139 	unsigned int		main_state;
140 	unsigned int		send_state;
141 	unsigned int		recv_state;
142 	unsigned long		flags;
143 	u8			rxid;
144 	u8			txid;
145 	unsigned int		txqueue_len;
146 	struct timer_list	tx_wd;
147 	struct timer_list	rx_wd;
148 	struct timer_list	keep_alive; /* wake-up workaround */
149 	spinlock_t		lock;
150 	struct net_device	*netdev;
151 	struct list_head	txqueue;
152 	struct list_head	cmdqueue;
153 	struct work_struct	work;
154 	struct hsi_client	*cl;
155 	struct list_head	link;
156 	atomic_t		tx_usecnt;
157 	int			channel_id_cmd;
158 	int			channel_id_data;
159 };
160 
161 /* List of ssi protocol instances */
162 static LIST_HEAD(ssip_list);
163 
164 static void ssip_rxcmd_complete(struct hsi_msg *msg);
165 
166 static inline void ssip_set_cmd(struct hsi_msg *msg, u32 cmd)
167 {
168 	u32 *data;
169 
170 	data = sg_virt(msg->sgt.sgl);
171 	*data = cmd;
172 }
173 
174 static inline u32 ssip_get_cmd(struct hsi_msg *msg)
175 {
176 	u32 *data;
177 
178 	data = sg_virt(msg->sgt.sgl);
179 
180 	return *data;
181 }
182 
183 static void ssip_skb_to_msg(struct sk_buff *skb, struct hsi_msg *msg)
184 {
185 	skb_frag_t *frag;
186 	struct scatterlist *sg;
187 	int i;
188 
189 	BUG_ON(msg->sgt.nents != (unsigned int)(skb_shinfo(skb)->nr_frags + 1));
190 
191 	sg = msg->sgt.sgl;
192 	sg_set_buf(sg, skb->data, skb_headlen(skb));
193 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
194 		sg = sg_next(sg);
195 		BUG_ON(!sg);
196 		frag = &skb_shinfo(skb)->frags[i];
197 		sg_set_page(sg, frag->page.p, frag->size, frag->page_offset);
198 	}
199 }
200 
201 static void ssip_free_data(struct hsi_msg *msg)
202 {
203 	struct sk_buff *skb;
204 
205 	skb = msg->context;
206 	pr_debug("free data: msg %p context %p skb %p\n", msg, msg->context,
207 								skb);
208 	msg->destructor = NULL;
209 	dev_kfree_skb(skb);
210 	hsi_free_msg(msg);
211 }
212 
213 static struct hsi_msg *ssip_alloc_data(struct ssi_protocol *ssi,
214 					struct sk_buff *skb, gfp_t flags)
215 {
216 	struct hsi_msg *msg;
217 
218 	msg = hsi_alloc_msg(skb_shinfo(skb)->nr_frags + 1, flags);
219 	if (!msg)
220 		return NULL;
221 	ssip_skb_to_msg(skb, msg);
222 	msg->destructor = ssip_free_data;
223 	msg->channel = ssi->channel_id_data;
224 	msg->context = skb;
225 
226 	return msg;
227 }
228 
229 static inline void ssip_release_cmd(struct hsi_msg *msg)
230 {
231 	struct ssi_protocol *ssi = hsi_client_drvdata(msg->cl);
232 
233 	dev_dbg(&msg->cl->device, "Release cmd 0x%08x\n", ssip_get_cmd(msg));
234 	spin_lock_bh(&ssi->lock);
235 	list_add_tail(&msg->link, &ssi->cmdqueue);
236 	spin_unlock_bh(&ssi->lock);
237 }
238 
239 static struct hsi_msg *ssip_claim_cmd(struct ssi_protocol *ssi)
240 {
241 	struct hsi_msg *msg;
242 
243 	BUG_ON(list_empty(&ssi->cmdqueue));
244 
245 	spin_lock_bh(&ssi->lock);
246 	msg = list_first_entry(&ssi->cmdqueue, struct hsi_msg, link);
247 	list_del(&msg->link);
248 	spin_unlock_bh(&ssi->lock);
249 	msg->destructor = ssip_release_cmd;
250 
251 	return msg;
252 }
253 
254 static void ssip_free_cmds(struct ssi_protocol *ssi)
255 {
256 	struct hsi_msg *msg, *tmp;
257 
258 	list_for_each_entry_safe(msg, tmp, &ssi->cmdqueue, link) {
259 		list_del(&msg->link);
260 		msg->destructor = NULL;
261 		kfree(sg_virt(msg->sgt.sgl));
262 		hsi_free_msg(msg);
263 	}
264 }
265 
266 static int ssip_alloc_cmds(struct ssi_protocol *ssi)
267 {
268 	struct hsi_msg *msg;
269 	u32 *buf;
270 	unsigned int i;
271 
272 	for (i = 0; i < SSIP_MAX_CMDS; i++) {
273 		msg = hsi_alloc_msg(1, GFP_KERNEL);
274 		if (!msg)
275 			goto out;
276 		buf = kmalloc(sizeof(*buf), GFP_KERNEL);
277 		if (!buf) {
278 			hsi_free_msg(msg);
279 			goto out;
280 		}
281 		sg_init_one(msg->sgt.sgl, buf, sizeof(*buf));
282 		msg->channel = ssi->channel_id_cmd;
283 		list_add_tail(&msg->link, &ssi->cmdqueue);
284 	}
285 
286 	return 0;
287 out:
288 	ssip_free_cmds(ssi);
289 
290 	return -ENOMEM;
291 }
292 
293 static void ssip_set_rxstate(struct ssi_protocol *ssi, unsigned int state)
294 {
295 	ssi->recv_state = state;
296 	switch (state) {
297 	case RECV_IDLE:
298 		del_timer(&ssi->rx_wd);
299 		if (ssi->send_state == SEND_IDLE)
300 			del_timer(&ssi->keep_alive);
301 		break;
302 	case RECV_READY:
303 		/* CMT speech workaround */
304 		if (atomic_read(&ssi->tx_usecnt))
305 			break;
306 		/* Otherwise fall through */
307 	case RECEIVING:
308 		mod_timer(&ssi->keep_alive, jiffies +
309 						msecs_to_jiffies(SSIP_KATOUT));
310 		mod_timer(&ssi->rx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
311 		break;
312 	default:
313 		break;
314 	}
315 }
316 
317 static void ssip_set_txstate(struct ssi_protocol *ssi, unsigned int state)
318 {
319 	ssi->send_state = state;
320 	switch (state) {
321 	case SEND_IDLE:
322 	case SEND_READY:
323 		del_timer(&ssi->tx_wd);
324 		if (ssi->recv_state == RECV_IDLE)
325 			del_timer(&ssi->keep_alive);
326 		break;
327 	case WAIT4READY:
328 	case SENDING:
329 	case SENDING_SWBREAK:
330 		mod_timer(&ssi->keep_alive,
331 				jiffies + msecs_to_jiffies(SSIP_KATOUT));
332 		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
333 		break;
334 	default:
335 		break;
336 	}
337 }
338 
339 struct hsi_client *ssip_slave_get_master(struct hsi_client *slave)
340 {
341 	struct hsi_client *master = ERR_PTR(-ENODEV);
342 	struct ssi_protocol *ssi;
343 
344 	list_for_each_entry(ssi, &ssip_list, link)
345 		if (slave->device.parent == ssi->cl->device.parent) {
346 			master = ssi->cl;
347 			break;
348 		}
349 
350 	return master;
351 }
352 EXPORT_SYMBOL_GPL(ssip_slave_get_master);
353 
354 int ssip_slave_start_tx(struct hsi_client *master)
355 {
356 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
357 
358 	dev_dbg(&master->device, "start TX %d\n", atomic_read(&ssi->tx_usecnt));
359 	spin_lock_bh(&ssi->lock);
360 	if (ssi->send_state == SEND_IDLE) {
361 		ssip_set_txstate(ssi, WAIT4READY);
362 		hsi_start_tx(master);
363 	}
364 	spin_unlock_bh(&ssi->lock);
365 	atomic_inc(&ssi->tx_usecnt);
366 
367 	return 0;
368 }
369 EXPORT_SYMBOL_GPL(ssip_slave_start_tx);
370 
371 int ssip_slave_stop_tx(struct hsi_client *master)
372 {
373 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
374 
375 	WARN_ON_ONCE(atomic_read(&ssi->tx_usecnt) == 0);
376 
377 	if (atomic_dec_and_test(&ssi->tx_usecnt)) {
378 		spin_lock_bh(&ssi->lock);
379 		if ((ssi->send_state == SEND_READY) ||
380 			(ssi->send_state == WAIT4READY)) {
381 			ssip_set_txstate(ssi, SEND_IDLE);
382 			hsi_stop_tx(master);
383 		}
384 		spin_unlock_bh(&ssi->lock);
385 	}
386 	dev_dbg(&master->device, "stop TX %d\n", atomic_read(&ssi->tx_usecnt));
387 
388 	return 0;
389 }
390 EXPORT_SYMBOL_GPL(ssip_slave_stop_tx);
391 
392 int ssip_slave_running(struct hsi_client *master)
393 {
394 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
395 	return netif_running(ssi->netdev);
396 }
397 EXPORT_SYMBOL_GPL(ssip_slave_running);
398 
399 static void ssip_reset(struct hsi_client *cl)
400 {
401 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
402 	struct list_head *head, *tmp;
403 	struct hsi_msg *msg;
404 
405 	if (netif_running(ssi->netdev))
406 		netif_carrier_off(ssi->netdev);
407 	hsi_flush(cl);
408 	spin_lock_bh(&ssi->lock);
409 	if (ssi->send_state != SEND_IDLE)
410 		hsi_stop_tx(cl);
411 	spin_unlock_bh(&ssi->lock);
412 	if (test_and_clear_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
413 		ssi_waketest(cl, 0); /* FIXME: To be removed */
414 	spin_lock_bh(&ssi->lock);
415 	del_timer(&ssi->rx_wd);
416 	del_timer(&ssi->tx_wd);
417 	del_timer(&ssi->keep_alive);
418 	ssi->main_state = 0;
419 	ssi->send_state = 0;
420 	ssi->recv_state = 0;
421 	ssi->flags = 0;
422 	ssi->rxid = 0;
423 	ssi->txid = 0;
424 	list_for_each_safe(head, tmp, &ssi->txqueue) {
425 		msg = list_entry(head, struct hsi_msg, link);
426 		dev_dbg(&cl->device, "Pending TX data\n");
427 		list_del(head);
428 		ssip_free_data(msg);
429 	}
430 	ssi->txqueue_len = 0;
431 	spin_unlock_bh(&ssi->lock);
432 }
433 
434 static void ssip_dump_state(struct hsi_client *cl)
435 {
436 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
437 	struct hsi_msg *msg;
438 
439 	spin_lock_bh(&ssi->lock);
440 	dev_err(&cl->device, "Main state: %d\n", ssi->main_state);
441 	dev_err(&cl->device, "Recv state: %d\n", ssi->recv_state);
442 	dev_err(&cl->device, "Send state: %d\n", ssi->send_state);
443 	dev_err(&cl->device, "CMT %s\n", (ssi->main_state == ACTIVE) ?
444 							"Online" : "Offline");
445 	dev_err(&cl->device, "Wake test %d\n",
446 				test_bit(SSIP_WAKETEST_FLAG, &ssi->flags));
447 	dev_err(&cl->device, "Data RX id: %d\n", ssi->rxid);
448 	dev_err(&cl->device, "Data TX id: %d\n", ssi->txid);
449 
450 	list_for_each_entry(msg, &ssi->txqueue, link)
451 		dev_err(&cl->device, "pending TX data (%p)\n", msg);
452 	spin_unlock_bh(&ssi->lock);
453 }
454 
455 static void ssip_error(struct hsi_client *cl)
456 {
457 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
458 	struct hsi_msg *msg;
459 
460 	ssip_dump_state(cl);
461 	ssip_reset(cl);
462 	msg = ssip_claim_cmd(ssi);
463 	msg->complete = ssip_rxcmd_complete;
464 	hsi_async_read(cl, msg);
465 }
466 
467 static void ssip_keep_alive(struct timer_list *t)
468 {
469 	struct ssi_protocol *ssi = from_timer(ssi, t, keep_alive);
470 	struct hsi_client *cl = ssi->cl;
471 
472 	dev_dbg(&cl->device, "Keep alive kick in: m(%d) r(%d) s(%d)\n",
473 		ssi->main_state, ssi->recv_state, ssi->send_state);
474 
475 	spin_lock(&ssi->lock);
476 	if (ssi->recv_state == RECV_IDLE)
477 		switch (ssi->send_state) {
478 		case SEND_READY:
479 			if (atomic_read(&ssi->tx_usecnt) == 0)
480 				break;
481 			/*
482 			 * Fall through. Workaround for cmt-speech
483 			 * in that case we relay on audio timers.
484 			 */
485 		case SEND_IDLE:
486 			spin_unlock(&ssi->lock);
487 			return;
488 		}
489 	mod_timer(&ssi->keep_alive, jiffies + msecs_to_jiffies(SSIP_KATOUT));
490 	spin_unlock(&ssi->lock);
491 }
492 
493 static void ssip_rx_wd(struct timer_list *t)
494 {
495 	struct ssi_protocol *ssi = from_timer(ssi, t, rx_wd);
496 	struct hsi_client *cl = ssi->cl;
497 
498 	dev_err(&cl->device, "Watchdog trigerred\n");
499 	ssip_error(cl);
500 }
501 
502 static void ssip_tx_wd(struct timer_list *t)
503 {
504 	struct ssi_protocol *ssi = from_timer(ssi, t, tx_wd);
505 	struct hsi_client *cl = ssi->cl;
506 
507 	dev_err(&cl->device, "Watchdog trigerred\n");
508 	ssip_error(cl);
509 }
510 
511 static void ssip_send_bootinfo_req_cmd(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, "Issuing BOOT INFO REQ command\n");
517 	msg = ssip_claim_cmd(ssi);
518 	ssip_set_cmd(msg, SSIP_BOOTINFO_REQ_CMD(SSIP_LOCAL_VERID));
519 	msg->complete = ssip_release_cmd;
520 	hsi_async_write(cl, msg);
521 	dev_dbg(&cl->device, "Issuing RX command\n");
522 	msg = ssip_claim_cmd(ssi);
523 	msg->complete = ssip_rxcmd_complete;
524 	hsi_async_read(cl, msg);
525 }
526 
527 static void ssip_start_rx(struct hsi_client *cl)
528 {
529 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
530 	struct hsi_msg *msg;
531 
532 	dev_dbg(&cl->device, "RX start M(%d) R(%d)\n", ssi->main_state,
533 						ssi->recv_state);
534 	spin_lock_bh(&ssi->lock);
535 	/*
536 	 * We can have two UP events in a row due to a short low
537 	 * high transition. Therefore we need to ignore the sencond UP event.
538 	 */
539 	if ((ssi->main_state != ACTIVE) || (ssi->recv_state == RECV_READY)) {
540 		spin_unlock_bh(&ssi->lock);
541 		return;
542 	}
543 	ssip_set_rxstate(ssi, RECV_READY);
544 	spin_unlock_bh(&ssi->lock);
545 
546 	msg = ssip_claim_cmd(ssi);
547 	ssip_set_cmd(msg, SSIP_READY_CMD);
548 	msg->complete = ssip_release_cmd;
549 	dev_dbg(&cl->device, "Send READY\n");
550 	hsi_async_write(cl, msg);
551 }
552 
553 static void ssip_stop_rx(struct hsi_client *cl)
554 {
555 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
556 
557 	dev_dbg(&cl->device, "RX stop M(%d)\n", ssi->main_state);
558 	spin_lock_bh(&ssi->lock);
559 	if (likely(ssi->main_state == ACTIVE))
560 		ssip_set_rxstate(ssi, RECV_IDLE);
561 	spin_unlock_bh(&ssi->lock);
562 }
563 
564 static void ssip_free_strans(struct hsi_msg *msg)
565 {
566 	ssip_free_data(msg->context);
567 	ssip_release_cmd(msg);
568 }
569 
570 static void ssip_strans_complete(struct hsi_msg *msg)
571 {
572 	struct hsi_client *cl = msg->cl;
573 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
574 	struct hsi_msg *data;
575 
576 	data = msg->context;
577 	ssip_release_cmd(msg);
578 	spin_lock_bh(&ssi->lock);
579 	ssip_set_txstate(ssi, SENDING);
580 	spin_unlock_bh(&ssi->lock);
581 	hsi_async_write(cl, data);
582 }
583 
584 static int ssip_xmit(struct hsi_client *cl)
585 {
586 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
587 	struct hsi_msg *msg, *dmsg;
588 	struct sk_buff *skb;
589 
590 	spin_lock_bh(&ssi->lock);
591 	if (list_empty(&ssi->txqueue)) {
592 		spin_unlock_bh(&ssi->lock);
593 		return 0;
594 	}
595 	dmsg = list_first_entry(&ssi->txqueue, struct hsi_msg, link);
596 	list_del(&dmsg->link);
597 	ssi->txqueue_len--;
598 	spin_unlock_bh(&ssi->lock);
599 
600 	msg = ssip_claim_cmd(ssi);
601 	skb = dmsg->context;
602 	msg->context = dmsg;
603 	msg->complete = ssip_strans_complete;
604 	msg->destructor = ssip_free_strans;
605 
606 	spin_lock_bh(&ssi->lock);
607 	ssip_set_cmd(msg, SSIP_START_TRANS_CMD(SSIP_BYTES_TO_FRAMES(skb->len),
608 								ssi->txid));
609 	ssi->txid++;
610 	ssip_set_txstate(ssi, SENDING);
611 	spin_unlock_bh(&ssi->lock);
612 
613 	dev_dbg(&cl->device, "Send STRANS (%d frames)\n",
614 						SSIP_BYTES_TO_FRAMES(skb->len));
615 
616 	return hsi_async_write(cl, msg);
617 }
618 
619 /* In soft IRQ context */
620 static void ssip_pn_rx(struct sk_buff *skb)
621 {
622 	struct net_device *dev = skb->dev;
623 
624 	if (unlikely(!netif_running(dev))) {
625 		dev_dbg(&dev->dev, "Drop RX packet\n");
626 		dev->stats.rx_dropped++;
627 		dev_kfree_skb(skb);
628 		return;
629 	}
630 	if (unlikely(!pskb_may_pull(skb, SSIP_MIN_PN_HDR))) {
631 		dev_dbg(&dev->dev, "Error drop RX packet\n");
632 		dev->stats.rx_errors++;
633 		dev->stats.rx_length_errors++;
634 		dev_kfree_skb(skb);
635 		return;
636 	}
637 	dev->stats.rx_packets++;
638 	dev->stats.rx_bytes += skb->len;
639 
640 	/* length field is exchanged in network byte order */
641 	((u16 *)skb->data)[2] = ntohs(((u16 *)skb->data)[2]);
642 	dev_dbg(&dev->dev, "RX length fixed (%04x -> %u)\n",
643 			((u16 *)skb->data)[2], ntohs(((u16 *)skb->data)[2]));
644 
645 	skb->protocol = htons(ETH_P_PHONET);
646 	skb_reset_mac_header(skb);
647 	__skb_pull(skb, 1);
648 	netif_rx(skb);
649 }
650 
651 static void ssip_rx_data_complete(struct hsi_msg *msg)
652 {
653 	struct hsi_client *cl = msg->cl;
654 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
655 	struct sk_buff *skb;
656 
657 	if (msg->status == HSI_STATUS_ERROR) {
658 		dev_err(&cl->device, "RX data error\n");
659 		ssip_free_data(msg);
660 		ssip_error(cl);
661 		return;
662 	}
663 	del_timer(&ssi->rx_wd); /* FIXME: Revisit */
664 	skb = msg->context;
665 	ssip_pn_rx(skb);
666 	hsi_free_msg(msg);
667 }
668 
669 static void ssip_rx_bootinforeq(struct hsi_client *cl, u32 cmd)
670 {
671 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
672 	struct hsi_msg *msg;
673 
674 	/* Workaroud: Ignore CMT Loader message leftover */
675 	if (cmd == SSIP_CMT_LOADER_SYNC)
676 		return;
677 
678 	switch (ssi->main_state) {
679 	case ACTIVE:
680 		dev_err(&cl->device, "Boot info req on active state\n");
681 		ssip_error(cl);
682 		/* Fall through */
683 	case INIT:
684 	case HANDSHAKE:
685 		spin_lock_bh(&ssi->lock);
686 		ssi->main_state = HANDSHAKE;
687 		spin_unlock_bh(&ssi->lock);
688 
689 		if (!test_and_set_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
690 			ssi_waketest(cl, 1); /* FIXME: To be removed */
691 
692 		spin_lock_bh(&ssi->lock);
693 		/* Start boot handshake watchdog */
694 		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
695 		spin_unlock_bh(&ssi->lock);
696 		dev_dbg(&cl->device, "Send BOOTINFO_RESP\n");
697 		if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
698 			dev_warn(&cl->device, "boot info req verid mismatch\n");
699 		msg = ssip_claim_cmd(ssi);
700 		ssip_set_cmd(msg, SSIP_BOOTINFO_RESP_CMD(SSIP_LOCAL_VERID));
701 		msg->complete = ssip_release_cmd;
702 		hsi_async_write(cl, msg);
703 		break;
704 	default:
705 		dev_dbg(&cl->device, "Wrong state M(%d)\n", ssi->main_state);
706 		break;
707 	}
708 }
709 
710 static void ssip_rx_bootinforesp(struct hsi_client *cl, u32 cmd)
711 {
712 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
713 
714 	if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
715 		dev_warn(&cl->device, "boot info resp verid mismatch\n");
716 
717 	spin_lock_bh(&ssi->lock);
718 	if (ssi->main_state != ACTIVE)
719 		/* Use tx_wd as a boot watchdog in non ACTIVE state */
720 		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
721 	else
722 		dev_dbg(&cl->device, "boot info resp ignored M(%d)\n",
723 							ssi->main_state);
724 	spin_unlock_bh(&ssi->lock);
725 }
726 
727 static void ssip_rx_waketest(struct hsi_client *cl, u32 cmd)
728 {
729 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
730 	unsigned int wkres = SSIP_PAYLOAD(cmd);
731 
732 	spin_lock_bh(&ssi->lock);
733 	if (ssi->main_state != HANDSHAKE) {
734 		dev_dbg(&cl->device, "wake lines test ignored M(%d)\n",
735 							ssi->main_state);
736 		spin_unlock_bh(&ssi->lock);
737 		return;
738 	}
739 	spin_unlock_bh(&ssi->lock);
740 
741 	if (test_and_clear_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
742 		ssi_waketest(cl, 0); /* FIXME: To be removed */
743 
744 	spin_lock_bh(&ssi->lock);
745 	ssi->main_state = ACTIVE;
746 	del_timer(&ssi->tx_wd); /* Stop boot handshake timer */
747 	spin_unlock_bh(&ssi->lock);
748 
749 	dev_notice(&cl->device, "WAKELINES TEST %s\n",
750 				wkres & SSIP_WAKETEST_FAILED ? "FAILED" : "OK");
751 	if (wkres & SSIP_WAKETEST_FAILED) {
752 		ssip_error(cl);
753 		return;
754 	}
755 	dev_dbg(&cl->device, "CMT is ONLINE\n");
756 	netif_wake_queue(ssi->netdev);
757 	netif_carrier_on(ssi->netdev);
758 }
759 
760 static void ssip_rx_ready(struct hsi_client *cl)
761 {
762 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
763 
764 	spin_lock_bh(&ssi->lock);
765 	if (unlikely(ssi->main_state != ACTIVE)) {
766 		dev_dbg(&cl->device, "READY on wrong state: S(%d) M(%d)\n",
767 					ssi->send_state, ssi->main_state);
768 		spin_unlock_bh(&ssi->lock);
769 		return;
770 	}
771 	if (ssi->send_state != WAIT4READY) {
772 		dev_dbg(&cl->device, "Ignore spurious READY command\n");
773 		spin_unlock_bh(&ssi->lock);
774 		return;
775 	}
776 	ssip_set_txstate(ssi, SEND_READY);
777 	spin_unlock_bh(&ssi->lock);
778 	ssip_xmit(cl);
779 }
780 
781 static void ssip_rx_strans(struct hsi_client *cl, u32 cmd)
782 {
783 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
784 	struct sk_buff *skb;
785 	struct hsi_msg *msg;
786 	int len = SSIP_PDU_LENGTH(cmd);
787 
788 	dev_dbg(&cl->device, "RX strans: %d frames\n", len);
789 	spin_lock_bh(&ssi->lock);
790 	if (unlikely(ssi->main_state != ACTIVE)) {
791 		dev_err(&cl->device, "START TRANS wrong state: S(%d) M(%d)\n",
792 					ssi->send_state, ssi->main_state);
793 		spin_unlock_bh(&ssi->lock);
794 		return;
795 	}
796 	ssip_set_rxstate(ssi, RECEIVING);
797 	if (unlikely(SSIP_MSG_ID(cmd) != ssi->rxid)) {
798 		dev_err(&cl->device, "START TRANS id %d expected %d\n",
799 					SSIP_MSG_ID(cmd), ssi->rxid);
800 		spin_unlock_bh(&ssi->lock);
801 		goto out1;
802 	}
803 	ssi->rxid++;
804 	spin_unlock_bh(&ssi->lock);
805 	skb = netdev_alloc_skb(ssi->netdev, len * 4);
806 	if (unlikely(!skb)) {
807 		dev_err(&cl->device, "No memory for rx skb\n");
808 		goto out1;
809 	}
810 	skb->dev = ssi->netdev;
811 	skb_put(skb, len * 4);
812 	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
813 	if (unlikely(!msg)) {
814 		dev_err(&cl->device, "No memory for RX data msg\n");
815 		goto out2;
816 	}
817 	msg->complete = ssip_rx_data_complete;
818 	hsi_async_read(cl, msg);
819 
820 	return;
821 out2:
822 	dev_kfree_skb(skb);
823 out1:
824 	ssip_error(cl);
825 }
826 
827 static void ssip_rxcmd_complete(struct hsi_msg *msg)
828 {
829 	struct hsi_client *cl = msg->cl;
830 	u32 cmd = ssip_get_cmd(msg);
831 	unsigned int cmdid = SSIP_COMMAND(cmd);
832 
833 	if (msg->status == HSI_STATUS_ERROR) {
834 		dev_err(&cl->device, "RX error detected\n");
835 		ssip_release_cmd(msg);
836 		ssip_error(cl);
837 		return;
838 	}
839 	hsi_async_read(cl, msg);
840 	dev_dbg(&cl->device, "RX cmd: 0x%08x\n", cmd);
841 	switch (cmdid) {
842 	case SSIP_SW_BREAK:
843 		/* Ignored */
844 		break;
845 	case SSIP_BOOTINFO_REQ:
846 		ssip_rx_bootinforeq(cl, cmd);
847 		break;
848 	case SSIP_BOOTINFO_RESP:
849 		ssip_rx_bootinforesp(cl, cmd);
850 		break;
851 	case SSIP_WAKETEST_RESULT:
852 		ssip_rx_waketest(cl, cmd);
853 		break;
854 	case SSIP_START_TRANS:
855 		ssip_rx_strans(cl, cmd);
856 		break;
857 	case SSIP_READY:
858 		ssip_rx_ready(cl);
859 		break;
860 	default:
861 		dev_warn(&cl->device, "command 0x%08x not supported\n", cmd);
862 		break;
863 	}
864 }
865 
866 static void ssip_swbreak_complete(struct hsi_msg *msg)
867 {
868 	struct hsi_client *cl = msg->cl;
869 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
870 
871 	ssip_release_cmd(msg);
872 	spin_lock_bh(&ssi->lock);
873 	if (list_empty(&ssi->txqueue)) {
874 		if (atomic_read(&ssi->tx_usecnt)) {
875 			ssip_set_txstate(ssi, SEND_READY);
876 		} else {
877 			ssip_set_txstate(ssi, SEND_IDLE);
878 			hsi_stop_tx(cl);
879 		}
880 		spin_unlock_bh(&ssi->lock);
881 	} else {
882 		spin_unlock_bh(&ssi->lock);
883 		ssip_xmit(cl);
884 	}
885 	netif_wake_queue(ssi->netdev);
886 }
887 
888 static void ssip_tx_data_complete(struct hsi_msg *msg)
889 {
890 	struct hsi_client *cl = msg->cl;
891 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
892 	struct hsi_msg *cmsg;
893 
894 	if (msg->status == HSI_STATUS_ERROR) {
895 		dev_err(&cl->device, "TX data error\n");
896 		ssip_error(cl);
897 		goto out;
898 	}
899 	spin_lock_bh(&ssi->lock);
900 	if (list_empty(&ssi->txqueue)) {
901 		ssip_set_txstate(ssi, SENDING_SWBREAK);
902 		spin_unlock_bh(&ssi->lock);
903 		cmsg = ssip_claim_cmd(ssi);
904 		ssip_set_cmd(cmsg, SSIP_SWBREAK_CMD);
905 		cmsg->complete = ssip_swbreak_complete;
906 		dev_dbg(&cl->device, "Send SWBREAK\n");
907 		hsi_async_write(cl, cmsg);
908 	} else {
909 		spin_unlock_bh(&ssi->lock);
910 		ssip_xmit(cl);
911 	}
912 out:
913 	ssip_free_data(msg);
914 }
915 
916 static void ssip_port_event(struct hsi_client *cl, unsigned long event)
917 {
918 	switch (event) {
919 	case HSI_EVENT_START_RX:
920 		ssip_start_rx(cl);
921 		break;
922 	case HSI_EVENT_STOP_RX:
923 		ssip_stop_rx(cl);
924 		break;
925 	default:
926 		return;
927 	}
928 }
929 
930 static int ssip_pn_open(struct net_device *dev)
931 {
932 	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
933 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
934 	int err;
935 
936 	err = hsi_claim_port(cl, 1);
937 	if (err < 0) {
938 		dev_err(&cl->device, "SSI port already claimed\n");
939 		return err;
940 	}
941 	err = hsi_register_port_event(cl, ssip_port_event);
942 	if (err < 0) {
943 		dev_err(&cl->device, "Register HSI port event failed (%d)\n",
944 			err);
945 		return err;
946 	}
947 	dev_dbg(&cl->device, "Configuring SSI port\n");
948 	hsi_setup(cl);
949 
950 	if (!test_and_set_bit(SSIP_WAKETEST_FLAG, &ssi->flags))
951 		ssi_waketest(cl, 1); /* FIXME: To be removed */
952 
953 	spin_lock_bh(&ssi->lock);
954 	ssi->main_state = HANDSHAKE;
955 	spin_unlock_bh(&ssi->lock);
956 
957 	ssip_send_bootinfo_req_cmd(cl);
958 
959 	return 0;
960 }
961 
962 static int ssip_pn_stop(struct net_device *dev)
963 {
964 	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
965 
966 	ssip_reset(cl);
967 	hsi_unregister_port_event(cl);
968 	hsi_release_port(cl);
969 
970 	return 0;
971 }
972 
973 static void ssip_xmit_work(struct work_struct *work)
974 {
975 	struct ssi_protocol *ssi =
976 				container_of(work, struct ssi_protocol, work);
977 	struct hsi_client *cl = ssi->cl;
978 
979 	ssip_xmit(cl);
980 }
981 
982 static int ssip_pn_xmit(struct sk_buff *skb, struct net_device *dev)
983 {
984 	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
985 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
986 	struct hsi_msg *msg;
987 
988 	if ((skb->protocol != htons(ETH_P_PHONET)) ||
989 					(skb->len < SSIP_MIN_PN_HDR))
990 		goto drop;
991 	/* Pad to 32-bits - FIXME: Revisit*/
992 	if ((skb->len & 3) && skb_pad(skb, 4 - (skb->len & 3)))
993 		goto inc_dropped;
994 
995 	/*
996 	 * Modem sends Phonet messages over SSI with its own endianess...
997 	 * Assume that modem has the same endianess as we do.
998 	 */
999 	if (skb_cow_head(skb, 0))
1000 		goto drop;
1001 
1002 	/* length field is exchanged in network byte order */
1003 	((u16 *)skb->data)[2] = htons(((u16 *)skb->data)[2]);
1004 
1005 	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
1006 	if (!msg) {
1007 		dev_dbg(&cl->device, "Dropping tx data: No memory\n");
1008 		goto drop;
1009 	}
1010 	msg->complete = ssip_tx_data_complete;
1011 
1012 	spin_lock_bh(&ssi->lock);
1013 	if (unlikely(ssi->main_state != ACTIVE)) {
1014 		spin_unlock_bh(&ssi->lock);
1015 		dev_dbg(&cl->device, "Dropping tx data: CMT is OFFLINE\n");
1016 		goto drop2;
1017 	}
1018 	list_add_tail(&msg->link, &ssi->txqueue);
1019 	ssi->txqueue_len++;
1020 	if (dev->tx_queue_len < ssi->txqueue_len) {
1021 		dev_info(&cl->device, "TX queue full %d\n", ssi->txqueue_len);
1022 		netif_stop_queue(dev);
1023 	}
1024 	if (ssi->send_state == SEND_IDLE) {
1025 		ssip_set_txstate(ssi, WAIT4READY);
1026 		spin_unlock_bh(&ssi->lock);
1027 		dev_dbg(&cl->device, "Start TX qlen %d\n", ssi->txqueue_len);
1028 		hsi_start_tx(cl);
1029 	} else if (ssi->send_state == SEND_READY) {
1030 		/* Needed for cmt-speech workaround */
1031 		dev_dbg(&cl->device, "Start TX on SEND READY qlen %d\n",
1032 							ssi->txqueue_len);
1033 		spin_unlock_bh(&ssi->lock);
1034 		schedule_work(&ssi->work);
1035 	} else {
1036 		spin_unlock_bh(&ssi->lock);
1037 	}
1038 	dev->stats.tx_packets++;
1039 	dev->stats.tx_bytes += skb->len;
1040 
1041 	return 0;
1042 drop2:
1043 	hsi_free_msg(msg);
1044 drop:
1045 	dev_kfree_skb(skb);
1046 inc_dropped:
1047 	dev->stats.tx_dropped++;
1048 
1049 	return 0;
1050 }
1051 
1052 /* CMT reset event handler */
1053 void ssip_reset_event(struct hsi_client *master)
1054 {
1055 	struct ssi_protocol *ssi = hsi_client_drvdata(master);
1056 	dev_err(&ssi->cl->device, "CMT reset detected!\n");
1057 	ssip_error(ssi->cl);
1058 }
1059 EXPORT_SYMBOL_GPL(ssip_reset_event);
1060 
1061 static const struct net_device_ops ssip_pn_ops = {
1062 	.ndo_open	= ssip_pn_open,
1063 	.ndo_stop	= ssip_pn_stop,
1064 	.ndo_start_xmit	= ssip_pn_xmit,
1065 };
1066 
1067 static void ssip_pn_setup(struct net_device *dev)
1068 {
1069 	dev->features		= 0;
1070 	dev->netdev_ops		= &ssip_pn_ops;
1071 	dev->type		= ARPHRD_PHONET;
1072 	dev->flags		= IFF_POINTOPOINT | IFF_NOARP;
1073 	dev->mtu		= SSIP_DEFAULT_MTU;
1074 	dev->hard_header_len	= 1;
1075 	dev->dev_addr[0]	= PN_MEDIA_SOS;
1076 	dev->addr_len		= 1;
1077 	dev->tx_queue_len	= SSIP_TXQUEUE_LEN;
1078 
1079 	dev->needs_free_netdev	= true;
1080 	dev->header_ops		= &phonet_header_ops;
1081 }
1082 
1083 static int ssi_protocol_probe(struct device *dev)
1084 {
1085 	static const char ifname[] = "phonet%d";
1086 	struct hsi_client *cl = to_hsi_client(dev);
1087 	struct ssi_protocol *ssi;
1088 	int err;
1089 
1090 	ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
1091 	if (!ssi) {
1092 		dev_err(dev, "No memory for ssi protocol\n");
1093 		return -ENOMEM;
1094 	}
1095 
1096 	spin_lock_init(&ssi->lock);
1097 	timer_setup(&ssi->rx_wd, ssip_rx_wd, TIMER_DEFERRABLE);
1098 	timer_setup(&ssi->tx_wd, ssip_tx_wd, TIMER_DEFERRABLE);
1099 	timer_setup(&ssi->keep_alive, ssip_keep_alive, 0);
1100 	INIT_LIST_HEAD(&ssi->txqueue);
1101 	INIT_LIST_HEAD(&ssi->cmdqueue);
1102 	atomic_set(&ssi->tx_usecnt, 0);
1103 	hsi_client_set_drvdata(cl, ssi);
1104 	ssi->cl = cl;
1105 	INIT_WORK(&ssi->work, ssip_xmit_work);
1106 
1107 	ssi->channel_id_cmd = hsi_get_channel_id_by_name(cl, "mcsaab-control");
1108 	if (ssi->channel_id_cmd < 0) {
1109 		err = ssi->channel_id_cmd;
1110 		dev_err(dev, "Could not get cmd channel (%d)\n", err);
1111 		goto out;
1112 	}
1113 
1114 	ssi->channel_id_data = hsi_get_channel_id_by_name(cl, "mcsaab-data");
1115 	if (ssi->channel_id_data < 0) {
1116 		err = ssi->channel_id_data;
1117 		dev_err(dev, "Could not get data channel (%d)\n", err);
1118 		goto out;
1119 	}
1120 
1121 	err = ssip_alloc_cmds(ssi);
1122 	if (err < 0) {
1123 		dev_err(dev, "No memory for commands\n");
1124 		goto out;
1125 	}
1126 
1127 	ssi->netdev = alloc_netdev(0, ifname, NET_NAME_UNKNOWN, ssip_pn_setup);
1128 	if (!ssi->netdev) {
1129 		dev_err(dev, "No memory for netdev\n");
1130 		err = -ENOMEM;
1131 		goto out1;
1132 	}
1133 
1134 	/* MTU range: 6 - 65535 */
1135 	ssi->netdev->min_mtu = PHONET_MIN_MTU;
1136 	ssi->netdev->max_mtu = SSIP_MAX_MTU;
1137 
1138 	SET_NETDEV_DEV(ssi->netdev, dev);
1139 	netif_carrier_off(ssi->netdev);
1140 	err = register_netdev(ssi->netdev);
1141 	if (err < 0) {
1142 		dev_err(dev, "Register netdev failed (%d)\n", err);
1143 		goto out2;
1144 	}
1145 
1146 	list_add(&ssi->link, &ssip_list);
1147 
1148 	dev_dbg(dev, "channel configuration: cmd=%d, data=%d\n",
1149 		ssi->channel_id_cmd, ssi->channel_id_data);
1150 
1151 	return 0;
1152 out2:
1153 	free_netdev(ssi->netdev);
1154 out1:
1155 	ssip_free_cmds(ssi);
1156 out:
1157 	kfree(ssi);
1158 
1159 	return err;
1160 }
1161 
1162 static int ssi_protocol_remove(struct device *dev)
1163 {
1164 	struct hsi_client *cl = to_hsi_client(dev);
1165 	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
1166 
1167 	list_del(&ssi->link);
1168 	unregister_netdev(ssi->netdev);
1169 	ssip_free_cmds(ssi);
1170 	hsi_client_set_drvdata(cl, NULL);
1171 	kfree(ssi);
1172 
1173 	return 0;
1174 }
1175 
1176 static struct hsi_client_driver ssip_driver = {
1177 	.driver = {
1178 		.name	= "ssi-protocol",
1179 		.owner	= THIS_MODULE,
1180 		.probe	= ssi_protocol_probe,
1181 		.remove	= ssi_protocol_remove,
1182 	},
1183 };
1184 
1185 static int __init ssip_init(void)
1186 {
1187 	pr_info("SSI protocol aka McSAAB added\n");
1188 
1189 	return hsi_register_client_driver(&ssip_driver);
1190 }
1191 module_init(ssip_init);
1192 
1193 static void __exit ssip_exit(void)
1194 {
1195 	hsi_unregister_client_driver(&ssip_driver);
1196 	pr_info("SSI protocol driver removed\n");
1197 }
1198 module_exit(ssip_exit);
1199 
1200 MODULE_ALIAS("hsi:ssi-protocol");
1201 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
1202 MODULE_AUTHOR("Remi Denis-Courmont <remi.denis-courmont@nokia.com>");
1203 MODULE_DESCRIPTION("SSI protocol improved aka McSAAB");
1204 MODULE_LICENSE("GPL");
1205