1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Shared Transport Line discipline driver Core
4  *	This hooks up ST KIM driver and ST LL driver
5  *  Copyright (C) 2009-2010 Texas Instruments
6  *  Author: Pavan Savoy <pavan_savoy@ti.com>
7  */
8 
9 #define pr_fmt(fmt)	"(stc): " fmt
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/tty.h>
13 
14 #include <linux/seq_file.h>
15 #include <linux/skbuff.h>
16 
17 #include <linux/ti_wilink_st.h>
18 
19 extern void st_kim_recv(void *, const unsigned char *, long);
20 void st_int_recv(void *, const unsigned char *, long);
21 /*
22  * function pointer pointing to either,
23  * st_kim_recv during registration to receive fw download responses
24  * st_int_recv after registration to receive proto stack responses
25  */
26 static void (*st_recv) (void *, const unsigned char *, long);
27 
28 /********************************************************************/
add_channel_to_table(struct st_data_s * st_gdata,struct st_proto_s * new_proto)29 static void add_channel_to_table(struct st_data_s *st_gdata,
30 		struct st_proto_s *new_proto)
31 {
32 	pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
33 	/* list now has the channel id as index itself */
34 	st_gdata->list[new_proto->chnl_id] = new_proto;
35 	st_gdata->is_registered[new_proto->chnl_id] = true;
36 }
37 
remove_channel_from_table(struct st_data_s * st_gdata,struct st_proto_s * proto)38 static void remove_channel_from_table(struct st_data_s *st_gdata,
39 		struct st_proto_s *proto)
40 {
41 	pr_info("%s: id %d\n", __func__, proto->chnl_id);
42 /*	st_gdata->list[proto->chnl_id] = NULL; */
43 	st_gdata->is_registered[proto->chnl_id] = false;
44 }
45 
46 /*
47  * called from KIM during firmware download.
48  *
49  * This is a wrapper function to tty->ops->write_room.
50  * It returns number of free space available in
51  * uart tx buffer.
52  */
st_get_uart_wr_room(struct st_data_s * st_gdata)53 int st_get_uart_wr_room(struct st_data_s *st_gdata)
54 {
55 	if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
56 		pr_err("tty unavailable to perform write");
57 		return -1;
58 	}
59 
60 	return tty_write_room(st_gdata->tty);
61 }
62 
63 /*
64  * can be called in from
65  * -- KIM (during fw download)
66  * -- ST Core (during st_write)
67  *
68  *  This is the internal write function - a wrapper
69  *  to tty->ops->write
70  */
st_int_write(struct st_data_s * st_gdata,const unsigned char * data,int count)71 int st_int_write(struct st_data_s *st_gdata,
72 	const unsigned char *data, int count)
73 {
74 	struct tty_struct *tty;
75 	if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
76 		pr_err("tty unavailable to perform write");
77 		return -EINVAL;
78 	}
79 	tty = st_gdata->tty;
80 #ifdef VERBOSE
81 	print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
82 		16, 1, data, count, 0);
83 #endif
84 	return tty->ops->write(tty, data, count);
85 
86 }
87 
88 /*
89  * push the skb received to relevant
90  * protocol stacks
91  */
st_send_frame(unsigned char chnl_id,struct st_data_s * st_gdata)92 static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
93 {
94 	pr_debug(" %s(prot:%d) ", __func__, chnl_id);
95 
96 	if (unlikely
97 	    (st_gdata == NULL || st_gdata->rx_skb == NULL
98 	     || st_gdata->is_registered[chnl_id] == false)) {
99 		pr_err("chnl_id %d not registered, no data to send?",
100 			   chnl_id);
101 		kfree_skb(st_gdata->rx_skb);
102 		return;
103 	}
104 	/*
105 	 * this cannot fail
106 	 * this shouldn't take long
107 	 * - should be just skb_queue_tail for the
108 	 *   protocol stack driver
109 	 */
110 	if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
111 		if (unlikely
112 			(st_gdata->list[chnl_id]->recv
113 			(st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
114 			     != 0)) {
115 			pr_err(" proto stack %d's ->recv failed", chnl_id);
116 			kfree_skb(st_gdata->rx_skb);
117 			return;
118 		}
119 	} else {
120 		pr_err(" proto stack %d's ->recv null", chnl_id);
121 		kfree_skb(st_gdata->rx_skb);
122 	}
123 	return;
124 }
125 
126 /*
127  * st_reg_complete - to call registration complete callbacks
128  * of all protocol stack drivers
129  * This function is being called with spin lock held, protocol drivers are
130  * only expected to complete their waits and do nothing more than that.
131  */
st_reg_complete(struct st_data_s * st_gdata,int err)132 static void st_reg_complete(struct st_data_s *st_gdata, int err)
133 {
134 	unsigned char i = 0;
135 	pr_info(" %s ", __func__);
136 	for (i = 0; i < ST_MAX_CHANNELS; i++) {
137 		if (likely(st_gdata != NULL &&
138 			st_gdata->is_registered[i] == true &&
139 				st_gdata->list[i]->reg_complete_cb != NULL)) {
140 			st_gdata->list[i]->reg_complete_cb
141 				(st_gdata->list[i]->priv_data, err);
142 			pr_info("protocol %d's cb sent %d\n", i, err);
143 			if (err) { /* cleanup registered protocol */
144 				st_gdata->is_registered[i] = false;
145 				if (st_gdata->protos_registered)
146 					st_gdata->protos_registered--;
147 			}
148 		}
149 	}
150 }
151 
st_check_data_len(struct st_data_s * st_gdata,unsigned char chnl_id,int len)152 static inline int st_check_data_len(struct st_data_s *st_gdata,
153 	unsigned char chnl_id, int len)
154 {
155 	int room = skb_tailroom(st_gdata->rx_skb);
156 
157 	pr_debug("len %d room %d", len, room);
158 
159 	if (!len) {
160 		/*
161 		 * Received packet has only packet header and
162 		 * has zero length payload. So, ask ST CORE to
163 		 * forward the packet to protocol driver (BT/FM/GPS)
164 		 */
165 		st_send_frame(chnl_id, st_gdata);
166 
167 	} else if (len > room) {
168 		/*
169 		 * Received packet's payload length is larger.
170 		 * We can't accommodate it in created skb.
171 		 */
172 		pr_err("Data length is too large len %d room %d", len,
173 			   room);
174 		kfree_skb(st_gdata->rx_skb);
175 	} else {
176 		/*
177 		 * Packet header has non-zero payload length and
178 		 * we have enough space in created skb. Lets read
179 		 * payload data */
180 		st_gdata->rx_state = ST_W4_DATA;
181 		st_gdata->rx_count = len;
182 		return len;
183 	}
184 
185 	/* Change ST state to continue to process next packet */
186 	st_gdata->rx_state = ST_W4_PACKET_TYPE;
187 	st_gdata->rx_skb = NULL;
188 	st_gdata->rx_count = 0;
189 	st_gdata->rx_chnl = 0;
190 
191 	return 0;
192 }
193 
194 /*
195  * st_wakeup_ack - internal function for action when wake-up ack
196  *	received
197  */
st_wakeup_ack(struct st_data_s * st_gdata,unsigned char cmd)198 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
199 	unsigned char cmd)
200 {
201 	struct sk_buff *waiting_skb;
202 	unsigned long flags = 0;
203 
204 	spin_lock_irqsave(&st_gdata->lock, flags);
205 	/*
206 	 * de-Q from waitQ and Q in txQ now that the
207 	 * chip is awake
208 	 */
209 	while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
210 		skb_queue_tail(&st_gdata->txq, waiting_skb);
211 
212 	/* state forwarded to ST LL */
213 	st_ll_sleep_state(st_gdata, (unsigned long)cmd);
214 	spin_unlock_irqrestore(&st_gdata->lock, flags);
215 
216 	/* wake up to send the recently copied skbs from waitQ */
217 	st_tx_wakeup(st_gdata);
218 }
219 
220 /*
221  * st_int_recv - ST's internal receive function.
222  *	Decodes received RAW data and forwards to corresponding
223  *	client drivers (Bluetooth,FM,GPS..etc).
224  *	This can receive various types of packets,
225  *	HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
226  *	CH-8 packets from FM, CH-9 packets from GPS cores.
227  */
st_int_recv(void * disc_data,const unsigned char * data,long count)228 void st_int_recv(void *disc_data,
229 	const unsigned char *data, long count)
230 {
231 	char *ptr;
232 	struct st_proto_s *proto;
233 	unsigned short payload_len = 0;
234 	int len = 0;
235 	unsigned char type = 0;
236 	unsigned char *plen;
237 	struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
238 	unsigned long flags;
239 
240 	ptr = (char *)data;
241 	/* tty_receive sent null ? */
242 	if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
243 		pr_err(" received null from TTY ");
244 		return;
245 	}
246 
247 	pr_debug("count %ld rx_state %ld"
248 		   "rx_count %ld", count, st_gdata->rx_state,
249 		   st_gdata->rx_count);
250 
251 	spin_lock_irqsave(&st_gdata->lock, flags);
252 	/* Decode received bytes here */
253 	while (count) {
254 		if (st_gdata->rx_count) {
255 			len = min_t(unsigned int, st_gdata->rx_count, count);
256 			skb_put_data(st_gdata->rx_skb, ptr, len);
257 			st_gdata->rx_count -= len;
258 			count -= len;
259 			ptr += len;
260 
261 			if (st_gdata->rx_count)
262 				continue;
263 
264 			/* Check ST RX state machine , where are we? */
265 			switch (st_gdata->rx_state) {
266 			/* Waiting for complete packet ? */
267 			case ST_W4_DATA:
268 				pr_debug("Complete pkt received");
269 				/*
270 				 * Ask ST CORE to forward
271 				 * the packet to protocol driver
272 				 */
273 				st_send_frame(st_gdata->rx_chnl, st_gdata);
274 
275 				st_gdata->rx_state = ST_W4_PACKET_TYPE;
276 				st_gdata->rx_skb = NULL;
277 				continue;
278 			/* parse the header to know details */
279 			case ST_W4_HEADER:
280 				proto = st_gdata->list[st_gdata->rx_chnl];
281 				plen =
282 				&st_gdata->rx_skb->data
283 				[proto->offset_len_in_hdr];
284 				pr_debug("plen pointing to %x\n", *plen);
285 				if (proto->len_size == 1) /* 1 byte len field */
286 					payload_len = *(unsigned char *)plen;
287 				else if (proto->len_size == 2)
288 					payload_len =
289 					__le16_to_cpu(*(unsigned short *)plen);
290 				else
291 					pr_info("%s: invalid length "
292 					"for id %d\n",
293 					__func__, proto->chnl_id);
294 				st_check_data_len(st_gdata, proto->chnl_id,
295 						payload_len);
296 				pr_debug("off %d, pay len %d\n",
297 					proto->offset_len_in_hdr, payload_len);
298 				continue;
299 			}	/* end of switch rx_state */
300 		}
301 
302 		/* end of if rx_count */
303 
304 		/*
305 		 * Check first byte of packet and identify module
306 		 * owner (BT/FM/GPS)
307 		 */
308 		switch (*ptr) {
309 		case LL_SLEEP_IND:
310 		case LL_SLEEP_ACK:
311 		case LL_WAKE_UP_IND:
312 			pr_debug("PM packet");
313 			/*
314 			 * this takes appropriate action based on
315 			 * sleep state received --
316 			 */
317 			st_ll_sleep_state(st_gdata, *ptr);
318 			/*
319 			 * if WAKEUP_IND collides copy from waitq to txq
320 			 * and assume chip awake
321 			 */
322 			spin_unlock_irqrestore(&st_gdata->lock, flags);
323 			if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
324 				st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
325 			spin_lock_irqsave(&st_gdata->lock, flags);
326 
327 			ptr++;
328 			count--;
329 			continue;
330 		case LL_WAKE_UP_ACK:
331 			pr_debug("PM packet");
332 
333 			spin_unlock_irqrestore(&st_gdata->lock, flags);
334 			/* wake up ack received */
335 			st_wakeup_ack(st_gdata, *ptr);
336 			spin_lock_irqsave(&st_gdata->lock, flags);
337 
338 			ptr++;
339 			count--;
340 			continue;
341 			/* Unknow packet? */
342 		default:
343 			type = *ptr;
344 
345 			/*
346 			 * Default case means non-HCILL packets,
347 			 * possibilities are packets for:
348 			 * (a) valid protocol -  Supported Protocols within
349 			 *     the ST_MAX_CHANNELS.
350 			 * (b) registered protocol - Checked by
351 			 *     "st_gdata->list[type] == NULL)" are supported
352 			 *     protocols only.
353 			 *  Rules out any invalid protocol and
354 			 *  unregistered protocols with channel ID < 16.
355 			 */
356 
357 			if ((type >= ST_MAX_CHANNELS) ||
358 					(st_gdata->list[type] == NULL)) {
359 				pr_err("chip/interface misbehavior: "
360 						"dropping frame starting "
361 						"with 0x%02x\n", type);
362 				goto done;
363 			}
364 
365 			st_gdata->rx_skb = alloc_skb(
366 					st_gdata->list[type]->max_frame_size,
367 					GFP_ATOMIC);
368 			if (st_gdata->rx_skb == NULL) {
369 				pr_err("out of memory: dropping\n");
370 				goto done;
371 			}
372 
373 			skb_reserve(st_gdata->rx_skb,
374 					st_gdata->list[type]->reserve);
375 			/* next 2 required for BT only */
376 			st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
377 			st_gdata->rx_skb->cb[1] = 0; /*incoming*/
378 			st_gdata->rx_chnl = *ptr;
379 			st_gdata->rx_state = ST_W4_HEADER;
380 			st_gdata->rx_count = st_gdata->list[type]->hdr_len;
381 			pr_debug("rx_count %ld\n", st_gdata->rx_count);
382 		}
383 		ptr++;
384 		count--;
385 	}
386 done:
387 	spin_unlock_irqrestore(&st_gdata->lock, flags);
388 	pr_debug("done %s", __func__);
389 	return;
390 }
391 
392 /*
393  * st_int_dequeue - internal de-Q function.
394  *	If the previous data set was not written
395  *	completely, return that skb which has the pending data.
396  *	In normal cases, return top of txq.
397  */
st_int_dequeue(struct st_data_s * st_gdata)398 static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
399 {
400 	struct sk_buff *returning_skb;
401 
402 	pr_debug("%s", __func__);
403 	if (st_gdata->tx_skb != NULL) {
404 		returning_skb = st_gdata->tx_skb;
405 		st_gdata->tx_skb = NULL;
406 		return returning_skb;
407 	}
408 	return skb_dequeue(&st_gdata->txq);
409 }
410 
411 /*
412  * st_int_enqueue - internal Q-ing function.
413  *	Will either Q the skb to txq or the tx_waitq
414  *	depending on the ST LL state.
415  *	If the chip is asleep, then Q it onto waitq and
416  *	wakeup the chip.
417  *	txq and waitq needs protection since the other contexts
418  *	may be sending data, waking up chip.
419  */
st_int_enqueue(struct st_data_s * st_gdata,struct sk_buff * skb)420 static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
421 {
422 	unsigned long flags = 0;
423 
424 	pr_debug("%s", __func__);
425 	spin_lock_irqsave(&st_gdata->lock, flags);
426 
427 	switch (st_ll_getstate(st_gdata)) {
428 	case ST_LL_AWAKE:
429 		pr_debug("ST LL is AWAKE, sending normally");
430 		skb_queue_tail(&st_gdata->txq, skb);
431 		break;
432 	case ST_LL_ASLEEP_TO_AWAKE:
433 		skb_queue_tail(&st_gdata->tx_waitq, skb);
434 		break;
435 	case ST_LL_AWAKE_TO_ASLEEP:
436 		pr_err("ST LL is illegal state(%ld),"
437 			   "purging received skb.", st_ll_getstate(st_gdata));
438 		kfree_skb(skb);
439 		break;
440 	case ST_LL_ASLEEP:
441 		skb_queue_tail(&st_gdata->tx_waitq, skb);
442 		st_ll_wakeup(st_gdata);
443 		break;
444 	default:
445 		pr_err("ST LL is illegal state(%ld),"
446 			   "purging received skb.", st_ll_getstate(st_gdata));
447 		kfree_skb(skb);
448 		break;
449 	}
450 
451 	spin_unlock_irqrestore(&st_gdata->lock, flags);
452 	pr_debug("done %s", __func__);
453 	return;
454 }
455 
456 /*
457  * internal wakeup function
458  * called from either
459  * - TTY layer when write's finished
460  * - st_write (in context of the protocol stack)
461  */
work_fn_write_wakeup(struct work_struct * work)462 static void work_fn_write_wakeup(struct work_struct *work)
463 {
464 	struct st_data_s *st_gdata = container_of(work, struct st_data_s,
465 			work_write_wakeup);
466 
467 	st_tx_wakeup((void *)st_gdata);
468 }
st_tx_wakeup(struct st_data_s * st_data)469 void st_tx_wakeup(struct st_data_s *st_data)
470 {
471 	struct sk_buff *skb;
472 	unsigned long flags;	/* for irq save flags */
473 	pr_debug("%s", __func__);
474 	/* check for sending & set flag sending here */
475 	if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
476 		pr_debug("ST already sending");
477 		/* keep sending */
478 		set_bit(ST_TX_WAKEUP, &st_data->tx_state);
479 		return;
480 		/* TX_WAKEUP will be checked in another
481 		 * context
482 		 */
483 	}
484 	do {			/* come back if st_tx_wakeup is set */
485 		/* woke-up to write */
486 		clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
487 		while ((skb = st_int_dequeue(st_data))) {
488 			int len;
489 			spin_lock_irqsave(&st_data->lock, flags);
490 			/* enable wake-up from TTY */
491 			set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
492 			len = st_int_write(st_data, skb->data, skb->len);
493 			skb_pull(skb, len);
494 			/* if skb->len = len as expected, skb->len=0 */
495 			if (skb->len) {
496 				/* would be the next skb to be sent */
497 				st_data->tx_skb = skb;
498 				spin_unlock_irqrestore(&st_data->lock, flags);
499 				break;
500 			}
501 			kfree_skb(skb);
502 			spin_unlock_irqrestore(&st_data->lock, flags);
503 		}
504 		/* if wake-up is set in another context- restart sending */
505 	} while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
506 
507 	/* clear flag sending */
508 	clear_bit(ST_TX_SENDING, &st_data->tx_state);
509 }
510 
511 /********************************************************************/
512 /* functions called from ST KIM
513 */
kim_st_list_protocols(struct st_data_s * st_gdata,void * buf)514 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
515 {
516 	seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
517 			st_gdata->protos_registered,
518 			st_gdata->is_registered[0x04] == true ? 'R' : 'U',
519 			st_gdata->is_registered[0x08] == true ? 'R' : 'U',
520 			st_gdata->is_registered[0x09] == true ? 'R' : 'U');
521 }
522 
523 /********************************************************************/
524 /*
525  * functions called from protocol stack drivers
526  * to be EXPORT-ed
527  */
st_register(struct st_proto_s * new_proto)528 long st_register(struct st_proto_s *new_proto)
529 {
530 	struct st_data_s	*st_gdata;
531 	long err = 0;
532 	unsigned long flags = 0;
533 
534 	st_kim_ref(&st_gdata, 0);
535 	if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
536 	    || new_proto->reg_complete_cb == NULL) {
537 		pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
538 		return -EINVAL;
539 	}
540 
541 	if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
542 		pr_err("chnl_id %d not supported", new_proto->chnl_id);
543 		return -EPROTONOSUPPORT;
544 	}
545 
546 	if (st_gdata->is_registered[new_proto->chnl_id] == true) {
547 		pr_err("chnl_id %d already registered", new_proto->chnl_id);
548 		return -EALREADY;
549 	}
550 
551 	/* can be from process context only */
552 	spin_lock_irqsave(&st_gdata->lock, flags);
553 
554 	if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
555 		pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
556 		/* fw download in progress */
557 
558 		add_channel_to_table(st_gdata, new_proto);
559 		st_gdata->protos_registered++;
560 		new_proto->write = st_write;
561 
562 		set_bit(ST_REG_PENDING, &st_gdata->st_state);
563 		spin_unlock_irqrestore(&st_gdata->lock, flags);
564 		return -EINPROGRESS;
565 	} else if (st_gdata->protos_registered == ST_EMPTY) {
566 		pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
567 		set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
568 		st_recv = st_kim_recv;
569 
570 		/* enable the ST LL - to set default chip state */
571 		st_ll_enable(st_gdata);
572 
573 		/* release lock previously held - re-locked below */
574 		spin_unlock_irqrestore(&st_gdata->lock, flags);
575 
576 		/*
577 		 * this may take a while to complete
578 		 * since it involves BT fw download
579 		 */
580 		err = st_kim_start(st_gdata->kim_data);
581 		if (err != 0) {
582 			clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
583 			if ((st_gdata->protos_registered != ST_EMPTY) &&
584 			    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
585 				pr_err(" KIM failure complete callback ");
586 				spin_lock_irqsave(&st_gdata->lock, flags);
587 				st_reg_complete(st_gdata, err);
588 				spin_unlock_irqrestore(&st_gdata->lock, flags);
589 				clear_bit(ST_REG_PENDING, &st_gdata->st_state);
590 			}
591 			return -EINVAL;
592 		}
593 
594 		spin_lock_irqsave(&st_gdata->lock, flags);
595 
596 		clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
597 		st_recv = st_int_recv;
598 
599 		/*
600 		 * this is where all pending registration
601 		 * are signalled to be complete by calling callback functions
602 		 */
603 		if ((st_gdata->protos_registered != ST_EMPTY) &&
604 		    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
605 			pr_debug(" call reg complete callback ");
606 			st_reg_complete(st_gdata, 0);
607 		}
608 		clear_bit(ST_REG_PENDING, &st_gdata->st_state);
609 
610 		/*
611 		 * check for already registered once more,
612 		 * since the above check is old
613 		 */
614 		if (st_gdata->is_registered[new_proto->chnl_id] == true) {
615 			pr_err(" proto %d already registered ",
616 				   new_proto->chnl_id);
617 			spin_unlock_irqrestore(&st_gdata->lock, flags);
618 			return -EALREADY;
619 		}
620 
621 		add_channel_to_table(st_gdata, new_proto);
622 		st_gdata->protos_registered++;
623 		new_proto->write = st_write;
624 		spin_unlock_irqrestore(&st_gdata->lock, flags);
625 		return err;
626 	}
627 	/* if fw is already downloaded & new stack registers protocol */
628 	else {
629 		add_channel_to_table(st_gdata, new_proto);
630 		st_gdata->protos_registered++;
631 		new_proto->write = st_write;
632 
633 		/* lock already held before entering else */
634 		spin_unlock_irqrestore(&st_gdata->lock, flags);
635 		return err;
636 	}
637 }
638 EXPORT_SYMBOL_GPL(st_register);
639 
640 /*
641  * to unregister a protocol -
642  * to be called from protocol stack driver
643  */
st_unregister(struct st_proto_s * proto)644 long st_unregister(struct st_proto_s *proto)
645 {
646 	long err = 0;
647 	unsigned long flags = 0;
648 	struct st_data_s	*st_gdata;
649 
650 	pr_debug("%s: %d ", __func__, proto->chnl_id);
651 
652 	st_kim_ref(&st_gdata, 0);
653 	if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
654 		pr_err(" chnl_id %d not supported", proto->chnl_id);
655 		return -EPROTONOSUPPORT;
656 	}
657 
658 	spin_lock_irqsave(&st_gdata->lock, flags);
659 
660 	if (st_gdata->is_registered[proto->chnl_id] == false) {
661 		pr_err(" chnl_id %d not registered", proto->chnl_id);
662 		spin_unlock_irqrestore(&st_gdata->lock, flags);
663 		return -EPROTONOSUPPORT;
664 	}
665 
666 	if (st_gdata->protos_registered)
667 		st_gdata->protos_registered--;
668 
669 	remove_channel_from_table(st_gdata, proto);
670 	spin_unlock_irqrestore(&st_gdata->lock, flags);
671 
672 	if ((st_gdata->protos_registered == ST_EMPTY) &&
673 	    (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
674 		pr_info(" all chnl_ids unregistered ");
675 
676 		/* stop traffic on tty */
677 		if (st_gdata->tty) {
678 			tty_ldisc_flush(st_gdata->tty);
679 			stop_tty(st_gdata->tty);
680 		}
681 
682 		/* all chnl_ids now unregistered */
683 		st_kim_stop(st_gdata->kim_data);
684 		/* disable ST LL */
685 		st_ll_disable(st_gdata);
686 	}
687 	return err;
688 }
689 
690 /*
691  * called in protocol stack drivers
692  * via the write function pointer
693  */
st_write(struct sk_buff * skb)694 long st_write(struct sk_buff *skb)
695 {
696 	struct st_data_s *st_gdata;
697 	long len;
698 
699 	st_kim_ref(&st_gdata, 0);
700 	if (unlikely(skb == NULL || st_gdata == NULL
701 		|| st_gdata->tty == NULL)) {
702 		pr_err("data/tty unavailable to perform write");
703 		return -EINVAL;
704 	}
705 
706 	pr_debug("%d to be written", skb->len);
707 	len = skb->len;
708 
709 	/* st_ll to decide where to enqueue the skb */
710 	st_int_enqueue(st_gdata, skb);
711 	/* wake up */
712 	st_tx_wakeup(st_gdata);
713 
714 	/* return number of bytes written */
715 	return len;
716 }
717 
718 /* for protocols making use of shared transport */
719 EXPORT_SYMBOL_GPL(st_unregister);
720 
721 /********************************************************************/
722 /*
723  * functions called from TTY layer
724  */
st_tty_open(struct tty_struct * tty)725 static int st_tty_open(struct tty_struct *tty)
726 {
727 	struct st_data_s *st_gdata;
728 	pr_info("%s ", __func__);
729 
730 	st_kim_ref(&st_gdata, 0);
731 	st_gdata->tty = tty;
732 	tty->disc_data = st_gdata;
733 
734 	/* don't do an wakeup for now */
735 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
736 
737 	/* mem already allocated
738 	 */
739 	tty->receive_room = 65536;
740 	/* Flush any pending characters in the driver and discipline. */
741 	tty_ldisc_flush(tty);
742 	tty_driver_flush_buffer(tty);
743 	/*
744 	 * signal to UIM via KIM that -
745 	 * installation of N_TI_WL ldisc is complete
746 	 */
747 	st_kim_complete(st_gdata->kim_data);
748 	pr_debug("done %s", __func__);
749 
750 	return 0;
751 }
752 
st_tty_close(struct tty_struct * tty)753 static void st_tty_close(struct tty_struct *tty)
754 {
755 	unsigned char i;
756 	unsigned long flags;
757 	struct	st_data_s *st_gdata = tty->disc_data;
758 
759 	pr_info("%s ", __func__);
760 
761 	/*
762 	 * TODO:
763 	 * if a protocol has been registered & line discipline
764 	 * un-installed for some reason - what should be done ?
765 	 */
766 	spin_lock_irqsave(&st_gdata->lock, flags);
767 	for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
768 		if (st_gdata->is_registered[i] == true)
769 			pr_err("%d not un-registered", i);
770 		st_gdata->list[i] = NULL;
771 		st_gdata->is_registered[i] = false;
772 	}
773 	st_gdata->protos_registered = 0;
774 	spin_unlock_irqrestore(&st_gdata->lock, flags);
775 	/*
776 	 * signal to UIM via KIM that -
777 	 * N_TI_WL ldisc is un-installed
778 	 */
779 	st_kim_complete(st_gdata->kim_data);
780 	st_gdata->tty = NULL;
781 	/* Flush any pending characters in the driver and discipline. */
782 	tty_ldisc_flush(tty);
783 	tty_driver_flush_buffer(tty);
784 
785 	spin_lock_irqsave(&st_gdata->lock, flags);
786 	/* empty out txq and tx_waitq */
787 	skb_queue_purge(&st_gdata->txq);
788 	skb_queue_purge(&st_gdata->tx_waitq);
789 	/* reset the TTY Rx states of ST */
790 	st_gdata->rx_count = 0;
791 	st_gdata->rx_state = ST_W4_PACKET_TYPE;
792 	kfree_skb(st_gdata->rx_skb);
793 	st_gdata->rx_skb = NULL;
794 	spin_unlock_irqrestore(&st_gdata->lock, flags);
795 
796 	pr_debug("%s: done ", __func__);
797 }
798 
st_tty_receive(struct tty_struct * tty,const unsigned char * data,const char * tty_flags,int count)799 static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
800 			   const char *tty_flags, int count)
801 {
802 #ifdef VERBOSE
803 	print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
804 		16, 1, data, count, 0);
805 #endif
806 
807 	/*
808 	 * if fw download is in progress then route incoming data
809 	 * to KIM for validation
810 	 */
811 	st_recv(tty->disc_data, data, count);
812 	pr_debug("done %s", __func__);
813 }
814 
815 /*
816  * wake-up function called in from the TTY layer
817  * inside the internal wakeup function will be called
818  */
st_tty_wakeup(struct tty_struct * tty)819 static void st_tty_wakeup(struct tty_struct *tty)
820 {
821 	struct	st_data_s *st_gdata = tty->disc_data;
822 	pr_debug("%s ", __func__);
823 	/* don't do an wakeup for now */
824 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
825 
826 	/*
827 	 * schedule the internal wakeup instead of calling directly to
828 	 * avoid lockup (port->lock needed in tty->ops->write is
829 	 * already taken here
830 	 */
831 	schedule_work(&st_gdata->work_write_wakeup);
832 }
833 
st_tty_flush_buffer(struct tty_struct * tty)834 static void st_tty_flush_buffer(struct tty_struct *tty)
835 {
836 	struct	st_data_s *st_gdata = tty->disc_data;
837 	pr_debug("%s ", __func__);
838 
839 	kfree_skb(st_gdata->tx_skb);
840 	st_gdata->tx_skb = NULL;
841 
842 	tty_driver_flush_buffer(tty);
843 	return;
844 }
845 
846 static struct tty_ldisc_ops st_ldisc_ops = {
847 	.num = N_TI_WL,
848 	.name = "n_st",
849 	.open = st_tty_open,
850 	.close = st_tty_close,
851 	.receive_buf = st_tty_receive,
852 	.write_wakeup = st_tty_wakeup,
853 	.flush_buffer = st_tty_flush_buffer,
854 	.owner = THIS_MODULE
855 };
856 
857 /********************************************************************/
st_core_init(struct st_data_s ** core_data)858 int st_core_init(struct st_data_s **core_data)
859 {
860 	struct st_data_s *st_gdata;
861 	long err;
862 
863 	err = tty_register_ldisc(&st_ldisc_ops);
864 	if (err) {
865 		pr_err("error registering %d line discipline %ld",
866 			   N_TI_WL, err);
867 		return err;
868 	}
869 	pr_debug("registered n_shared line discipline");
870 
871 	st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
872 	if (!st_gdata) {
873 		pr_err("memory allocation failed");
874 		err = -ENOMEM;
875 		goto err_unreg_ldisc;
876 	}
877 
878 	/* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
879 	 * will be pushed in this queue for actual transmission.
880 	 */
881 	skb_queue_head_init(&st_gdata->txq);
882 	skb_queue_head_init(&st_gdata->tx_waitq);
883 
884 	/* Locking used in st_int_enqueue() to avoid multiple execution */
885 	spin_lock_init(&st_gdata->lock);
886 
887 	err = st_ll_init(st_gdata);
888 	if (err) {
889 		pr_err("error during st_ll initialization(%ld)", err);
890 		goto err_free_gdata;
891 	}
892 
893 	INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
894 
895 	*core_data = st_gdata;
896 	return 0;
897 err_free_gdata:
898 	kfree(st_gdata);
899 err_unreg_ldisc:
900 	tty_unregister_ldisc(&st_ldisc_ops);
901 	return err;
902 }
903 
st_core_exit(struct st_data_s * st_gdata)904 void st_core_exit(struct st_data_s *st_gdata)
905 {
906 	long err;
907 	/* internal module cleanup */
908 	err = st_ll_deinit(st_gdata);
909 	if (err)
910 		pr_err("error during deinit of ST LL %ld", err);
911 
912 	if (st_gdata != NULL) {
913 		/* Free ST Tx Qs and skbs */
914 		skb_queue_purge(&st_gdata->txq);
915 		skb_queue_purge(&st_gdata->tx_waitq);
916 		kfree_skb(st_gdata->rx_skb);
917 		kfree_skb(st_gdata->tx_skb);
918 		/* TTY ldisc cleanup */
919 		tty_unregister_ldisc(&st_ldisc_ops);
920 		/* free the global data pointer */
921 		kfree(st_gdata);
922 	}
923 }
924