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
48void 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 */
92enum {
93	INIT,
94	HANDSHAKE,
95	ACTIVE,
96};
97
98/* Send state machine states */
99enum {
100	SEND_IDLE,
101	WAIT4READY,
102	SEND_READY,
103	SENDING,
104	SENDING_SWBREAK,
105};
106
107/* Receive state machine states */
108enum {
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 */
136struct 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 */
159static LIST_HEAD(ssip_list);
160
161static void ssip_rxcmd_complete(struct hsi_msg *msg);
162
163static 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
171static 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
180static 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
198static 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
210static 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
226static 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
236static 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
251static 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
263static 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;
284out:
285	ssip_free_cmds(ssi);
286
287	return -ENOMEM;
288}
289
290static 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
314static 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
336struct 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}
349EXPORT_SYMBOL_GPL(ssip_slave_get_master);
350
351int 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}
366EXPORT_SYMBOL_GPL(ssip_slave_start_tx);
367
368int 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}
387EXPORT_SYMBOL_GPL(ssip_slave_stop_tx);
388
389int ssip_slave_running(struct hsi_client *master)
390{
391	struct ssi_protocol *ssi = hsi_client_drvdata(master);
392	return netif_running(ssi->netdev);
393}
394EXPORT_SYMBOL_GPL(ssip_slave_running);
395
396static 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
429static 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
449static 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
461static 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
487static 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
495static 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
511static 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
543static 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
554static void ssip_free_strans(struct hsi_msg *msg)
555{
556	ssip_free_data(msg->context);
557	ssip_release_cmd(msg);
558}
559
560static 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
574static 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 */
610static 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
641static 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
659static 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
700static 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
717static 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
748static 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
769static 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;
809out2:
810	dev_kfree_skb(skb);
811out1:
812	ssip_error(cl);
813}
814
815static 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
854static 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
876static 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	}
900out:
901	ssip_free_data(msg);
902}
903
904static 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
918static 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
948static 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
959static 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
968static 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;
1028drop2:
1029	hsi_free_msg(msg);
1030drop:
1031	dev->stats.tx_dropped++;
1032	dev_kfree_skb(skb);
1033
1034	return 0;
1035}
1036
1037/* CMT reset event handler */
1038void 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}
1044EXPORT_SYMBOL_GPL(ssip_reset_event);
1045
1046static 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
1053static 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
1069static 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;
1139out2:
1140	free_netdev(ssi->netdev);
1141out1:
1142	ssip_free_cmds(ssi);
1143out:
1144	kfree(ssi);
1145
1146	return err;
1147}
1148
1149static 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
1163static 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
1172static 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}
1178module_init(ssip_init);
1179
1180static void __exit ssip_exit(void)
1181{
1182	hsi_unregister_client_driver(&ssip_driver);
1183	pr_info("SSI protocol driver removed\n");
1184}
1185module_exit(ssip_exit);
1186
1187MODULE_ALIAS("hsi:ssi-protocol");
1188MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
1189MODULE_AUTHOR("Remi Denis-Courmont <remi.denis-courmont@nokia.com>");
1190MODULE_DESCRIPTION("SSI protocol improved aka McSAAB");
1191MODULE_LICENSE("GPL");
1192