xref: /linux/drivers/misc/ti-st/st_core.c (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
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 #include <linux/netdevice.h>
19 
20 /*
21  * function pointer pointing to either,
22  * st_kim_recv during registration to receive fw download responses
23  * st_int_recv after registration to receive proto stack responses
24  */
25 static void (*st_recv)(void *disc_data, const u8 *ptr, size_t count);
26 
27 /********************************************************************/
add_channel_to_table(struct st_data_s * st_gdata,struct st_proto_s * new_proto)28 static void add_channel_to_table(struct st_data_s *st_gdata,
29 		struct st_proto_s *new_proto)
30 {
31 	pr_info("%s: id %d\n", __func__, new_proto->chnl_id);
32 	/* list now has the channel id as index itself */
33 	st_gdata->list[new_proto->chnl_id] = new_proto;
34 	st_gdata->is_registered[new_proto->chnl_id] = true;
35 }
36 
remove_channel_from_table(struct st_data_s * st_gdata,struct st_proto_s * proto)37 static void remove_channel_from_table(struct st_data_s *st_gdata,
38 		struct st_proto_s *proto)
39 {
40 	pr_info("%s: id %d\n", __func__, proto->chnl_id);
41 /*	st_gdata->list[proto->chnl_id] = NULL; */
42 	st_gdata->is_registered[proto->chnl_id] = false;
43 }
44 
45 /*
46  * called from KIM during firmware download.
47  *
48  * This is a wrapper function to tty->ops->write_room.
49  * It returns number of free space available in
50  * uart tx buffer.
51  */
st_get_uart_wr_room(struct st_data_s * st_gdata)52 int st_get_uart_wr_room(struct st_data_s *st_gdata)
53 {
54 	if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
55 		pr_err("tty unavailable to perform write");
56 		return -1;
57 	}
58 
59 	return tty_write_room(st_gdata->tty);
60 }
61 
62 /*
63  * can be called in from
64  * -- KIM (during fw download)
65  * -- ST Core (during st_write)
66  *
67  *  This is the internal write function - a wrapper
68  *  to tty->ops->write
69  */
st_int_write(struct st_data_s * st_gdata,const unsigned char * data,int count)70 int st_int_write(struct st_data_s *st_gdata,
71 	const unsigned char *data, int count)
72 {
73 	struct tty_struct *tty;
74 	if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
75 		pr_err("tty unavailable to perform write");
76 		return -EINVAL;
77 	}
78 	tty = st_gdata->tty;
79 #ifdef VERBOSE
80 	print_hex_dump(KERN_DEBUG, "<out<", DUMP_PREFIX_NONE,
81 		16, 1, data, count, 0);
82 #endif
83 	return tty->ops->write(tty, data, count);
84 
85 }
86 
87 /*
88  * push the skb received to relevant
89  * protocol stacks
90  */
st_send_frame(unsigned char chnl_id,struct st_data_s * st_gdata)91 static void st_send_frame(unsigned char chnl_id, struct st_data_s *st_gdata)
92 {
93 	pr_debug(" %s(prot:%d) ", __func__, chnl_id);
94 
95 	if (unlikely
96 	    (st_gdata == NULL || st_gdata->rx_skb == NULL
97 	     || st_gdata->is_registered[chnl_id] == false)) {
98 		pr_err("chnl_id %d not registered, no data to send?",
99 			   chnl_id);
100 		kfree_skb(st_gdata->rx_skb);
101 		return;
102 	}
103 	/*
104 	 * this cannot fail
105 	 * this shouldn't take long
106 	 * - should be just skb_queue_tail for the
107 	 *   protocol stack driver
108 	 */
109 	if (likely(st_gdata->list[chnl_id]->recv != NULL)) {
110 		if (unlikely
111 			(st_gdata->list[chnl_id]->recv
112 			(st_gdata->list[chnl_id]->priv_data, st_gdata->rx_skb)
113 			     != 0)) {
114 			pr_err(" proto stack %d's ->recv failed", chnl_id);
115 			kfree_skb(st_gdata->rx_skb);
116 			return;
117 		}
118 	} else {
119 		pr_err(" proto stack %d's ->recv null", chnl_id);
120 		kfree_skb(st_gdata->rx_skb);
121 	}
122 	return;
123 }
124 
125 /*
126  * st_reg_complete - to call registration complete callbacks
127  * of all protocol stack drivers
128  * This function is being called with spin lock held, protocol drivers are
129  * only expected to complete their waits and do nothing more than that.
130  */
st_reg_complete(struct st_data_s * st_gdata,int err)131 static void st_reg_complete(struct st_data_s *st_gdata, int err)
132 {
133 	unsigned char i = 0;
134 	pr_info(" %s ", __func__);
135 	for (i = 0; i < ST_MAX_CHANNELS; i++) {
136 		if (likely(st_gdata != NULL &&
137 			st_gdata->is_registered[i] == true &&
138 				st_gdata->list[i]->reg_complete_cb != NULL)) {
139 			st_gdata->list[i]->reg_complete_cb
140 				(st_gdata->list[i]->priv_data, err);
141 			pr_info("protocol %d's cb sent %d\n", i, err);
142 			if (err) { /* cleanup registered protocol */
143 				st_gdata->is_registered[i] = false;
144 				if (st_gdata->protos_registered)
145 					st_gdata->protos_registered--;
146 			}
147 		}
148 	}
149 }
150 
st_check_data_len(struct st_data_s * st_gdata,unsigned char chnl_id,int len)151 static inline int st_check_data_len(struct st_data_s *st_gdata,
152 	unsigned char chnl_id, int len)
153 {
154 	int room = skb_tailroom(st_gdata->rx_skb);
155 
156 	pr_debug("len %d room %d", len, room);
157 
158 	if (!len) {
159 		/*
160 		 * Received packet has only packet header and
161 		 * has zero length payload. So, ask ST CORE to
162 		 * forward the packet to protocol driver (BT/FM/GPS)
163 		 */
164 		st_send_frame(chnl_id, st_gdata);
165 
166 	} else if (len > room) {
167 		/*
168 		 * Received packet's payload length is larger.
169 		 * We can't accommodate it in created skb.
170 		 */
171 		pr_err("Data length is too large len %d room %d", len,
172 			   room);
173 		kfree_skb(st_gdata->rx_skb);
174 	} else {
175 		/*
176 		 * Packet header has non-zero payload length and
177 		 * we have enough space in created skb. Lets read
178 		 * payload data */
179 		st_gdata->rx_state = ST_W4_DATA;
180 		st_gdata->rx_count = len;
181 		return len;
182 	}
183 
184 	/* Change ST state to continue to process next packet */
185 	st_gdata->rx_state = ST_W4_PACKET_TYPE;
186 	st_gdata->rx_skb = NULL;
187 	st_gdata->rx_count = 0;
188 	st_gdata->rx_chnl = 0;
189 
190 	return 0;
191 }
192 
193 /*
194  * st_wakeup_ack - internal function for action when wake-up ack
195  *	received
196  */
st_wakeup_ack(struct st_data_s * st_gdata,unsigned char cmd)197 static inline void st_wakeup_ack(struct st_data_s *st_gdata,
198 	unsigned char cmd)
199 {
200 	struct sk_buff *waiting_skb;
201 	unsigned long flags = 0;
202 
203 	spin_lock_irqsave(&st_gdata->lock, flags);
204 	/*
205 	 * de-Q from waitQ and Q in txQ now that the
206 	 * chip is awake
207 	 */
208 	while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
209 		skb_queue_tail(&st_gdata->txq, waiting_skb);
210 
211 	/* state forwarded to ST LL */
212 	st_ll_sleep_state(st_gdata, (unsigned long)cmd);
213 	spin_unlock_irqrestore(&st_gdata->lock, flags);
214 
215 	/* wake up to send the recently copied skbs from waitQ */
216 	st_tx_wakeup(st_gdata);
217 }
218 
219 /*
220  * st_int_recv - ST's internal receive function.
221  *	Decodes received RAW data and forwards to corresponding
222  *	client drivers (Bluetooth,FM,GPS..etc).
223  *	This can receive various types of packets,
224  *	HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
225  *	CH-8 packets from FM, CH-9 packets from GPS cores.
226  */
st_int_recv(void * disc_data,const u8 * ptr,size_t count)227 static void st_int_recv(void *disc_data, const u8 *ptr, size_t count)
228 {
229 	struct st_proto_s *proto;
230 	unsigned short payload_len = 0;
231 	int len = 0;
232 	unsigned char type = 0;
233 	unsigned char *plen;
234 	struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
235 	unsigned long flags;
236 
237 	if (st_gdata == NULL) {
238 		pr_err(" received null from TTY ");
239 		return;
240 	}
241 
242 	pr_debug("count %zu rx_state %ld"
243 		   "rx_count %ld", count, st_gdata->rx_state,
244 		   st_gdata->rx_count);
245 
246 	spin_lock_irqsave(&st_gdata->lock, flags);
247 	/* Decode received bytes here */
248 	while (count) {
249 		if (st_gdata->rx_count) {
250 			len = min_t(unsigned int, st_gdata->rx_count, count);
251 			skb_put_data(st_gdata->rx_skb, ptr, len);
252 			st_gdata->rx_count -= len;
253 			count -= len;
254 			ptr += len;
255 
256 			if (st_gdata->rx_count)
257 				continue;
258 
259 			/* Check ST RX state machine , where are we? */
260 			switch (st_gdata->rx_state) {
261 			/* Waiting for complete packet ? */
262 			case ST_W4_DATA:
263 				pr_debug("Complete pkt received");
264 				/*
265 				 * Ask ST CORE to forward
266 				 * the packet to protocol driver
267 				 */
268 				st_send_frame(st_gdata->rx_chnl, st_gdata);
269 
270 				st_gdata->rx_state = ST_W4_PACKET_TYPE;
271 				st_gdata->rx_skb = NULL;
272 				continue;
273 			/* parse the header to know details */
274 			case ST_W4_HEADER:
275 				proto = st_gdata->list[st_gdata->rx_chnl];
276 				plen =
277 				&st_gdata->rx_skb->data
278 				[proto->offset_len_in_hdr];
279 				pr_debug("plen pointing to %x\n", *plen);
280 				if (proto->len_size == 1) /* 1 byte len field */
281 					payload_len = *(unsigned char *)plen;
282 				else if (proto->len_size == 2)
283 					payload_len =
284 					__le16_to_cpu(*(unsigned short *)plen);
285 				else
286 					pr_info("%s: invalid length "
287 					"for id %d\n",
288 					__func__, proto->chnl_id);
289 				st_check_data_len(st_gdata, proto->chnl_id,
290 						payload_len);
291 				pr_debug("off %d, pay len %d\n",
292 					proto->offset_len_in_hdr, payload_len);
293 				continue;
294 			}	/* end of switch rx_state */
295 		}
296 
297 		/* end of if rx_count */
298 
299 		/*
300 		 * Check first byte of packet and identify module
301 		 * owner (BT/FM/GPS)
302 		 */
303 		switch (*ptr) {
304 		case LL_SLEEP_IND:
305 		case LL_SLEEP_ACK:
306 		case LL_WAKE_UP_IND:
307 			pr_debug("PM packet");
308 			/*
309 			 * this takes appropriate action based on
310 			 * sleep state received --
311 			 */
312 			st_ll_sleep_state(st_gdata, *ptr);
313 			/*
314 			 * if WAKEUP_IND collides copy from waitq to txq
315 			 * and assume chip awake
316 			 */
317 			spin_unlock_irqrestore(&st_gdata->lock, flags);
318 			if (st_ll_getstate(st_gdata) == ST_LL_AWAKE)
319 				st_wakeup_ack(st_gdata, LL_WAKE_UP_ACK);
320 			spin_lock_irqsave(&st_gdata->lock, flags);
321 
322 			ptr++;
323 			count--;
324 			continue;
325 		case LL_WAKE_UP_ACK:
326 			pr_debug("PM packet");
327 
328 			spin_unlock_irqrestore(&st_gdata->lock, flags);
329 			/* wake up ack received */
330 			st_wakeup_ack(st_gdata, *ptr);
331 			spin_lock_irqsave(&st_gdata->lock, flags);
332 
333 			ptr++;
334 			count--;
335 			continue;
336 			/* Unknown packet? */
337 		default:
338 			type = *ptr;
339 
340 			/*
341 			 * Default case means non-HCILL packets,
342 			 * possibilities are packets for:
343 			 * (a) valid protocol -  Supported Protocols within
344 			 *     the ST_MAX_CHANNELS.
345 			 * (b) registered protocol - Checked by
346 			 *     "st_gdata->list[type] == NULL)" are supported
347 			 *     protocols only.
348 			 *  Rules out any invalid protocol and
349 			 *  unregistered protocols with channel ID < 16.
350 			 */
351 
352 			if ((type >= ST_MAX_CHANNELS) ||
353 					(st_gdata->list[type] == NULL)) {
354 				pr_err("chip/interface misbehavior: "
355 						"dropping frame starting "
356 						"with 0x%02x\n", type);
357 				goto done;
358 			}
359 
360 			st_gdata->rx_skb = alloc_skb(
361 					st_gdata->list[type]->max_frame_size,
362 					GFP_ATOMIC);
363 			if (st_gdata->rx_skb == NULL) {
364 				pr_err("out of memory: dropping\n");
365 				goto done;
366 			}
367 
368 			skb_reserve(st_gdata->rx_skb,
369 					st_gdata->list[type]->reserve);
370 			/* next 2 required for BT only */
371 			st_gdata->rx_skb->cb[0] = type; /*pkt_type*/
372 			st_gdata->rx_skb->cb[1] = 0; /*incoming*/
373 			st_gdata->rx_chnl = *ptr;
374 			st_gdata->rx_state = ST_W4_HEADER;
375 			st_gdata->rx_count = st_gdata->list[type]->hdr_len;
376 			pr_debug("rx_count %ld\n", st_gdata->rx_count);
377 		}
378 		ptr++;
379 		count--;
380 	}
381 done:
382 	spin_unlock_irqrestore(&st_gdata->lock, flags);
383 	pr_debug("done %s", __func__);
384 	return;
385 }
386 
387 /*
388  * st_int_dequeue - internal de-Q function.
389  *	If the previous data set was not written
390  *	completely, return that skb which has the pending data.
391  *	In normal cases, return top of txq.
392  */
st_int_dequeue(struct st_data_s * st_gdata)393 static struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
394 {
395 	struct sk_buff *returning_skb;
396 
397 	pr_debug("%s", __func__);
398 	if (st_gdata->tx_skb != NULL) {
399 		returning_skb = st_gdata->tx_skb;
400 		st_gdata->tx_skb = NULL;
401 		return returning_skb;
402 	}
403 	return skb_dequeue(&st_gdata->txq);
404 }
405 
406 /*
407  * st_int_enqueue - internal Q-ing function.
408  *	Will either Q the skb to txq or the tx_waitq
409  *	depending on the ST LL state.
410  *	If the chip is asleep, then Q it onto waitq and
411  *	wakeup the chip.
412  *	txq and waitq needs protection since the other contexts
413  *	may be sending data, waking up chip.
414  */
st_int_enqueue(struct st_data_s * st_gdata,struct sk_buff * skb)415 static void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
416 {
417 	unsigned long flags = 0;
418 
419 	pr_debug("%s", __func__);
420 	spin_lock_irqsave(&st_gdata->lock, flags);
421 
422 	switch (st_ll_getstate(st_gdata)) {
423 	case ST_LL_AWAKE:
424 		pr_debug("ST LL is AWAKE, sending normally");
425 		skb_queue_tail(&st_gdata->txq, skb);
426 		break;
427 	case ST_LL_ASLEEP_TO_AWAKE:
428 		skb_queue_tail(&st_gdata->tx_waitq, skb);
429 		break;
430 	case ST_LL_AWAKE_TO_ASLEEP:
431 		pr_err("ST LL is illegal state(%ld),"
432 			   "purging received skb.", st_ll_getstate(st_gdata));
433 		dev_kfree_skb_irq(skb);
434 		break;
435 	case ST_LL_ASLEEP:
436 		skb_queue_tail(&st_gdata->tx_waitq, skb);
437 		st_ll_wakeup(st_gdata);
438 		break;
439 	default:
440 		pr_err("ST LL is illegal state(%ld),"
441 			   "purging received skb.", st_ll_getstate(st_gdata));
442 		dev_kfree_skb_irq(skb);
443 		break;
444 	}
445 
446 	spin_unlock_irqrestore(&st_gdata->lock, flags);
447 	pr_debug("done %s", __func__);
448 	return;
449 }
450 
451 /*
452  * internal wakeup function
453  * called from either
454  * - TTY layer when write's finished
455  * - st_write (in context of the protocol stack)
456  */
work_fn_write_wakeup(struct work_struct * work)457 static void work_fn_write_wakeup(struct work_struct *work)
458 {
459 	struct st_data_s *st_gdata = container_of(work, struct st_data_s,
460 			work_write_wakeup);
461 
462 	st_tx_wakeup((void *)st_gdata);
463 }
st_tx_wakeup(struct st_data_s * st_data)464 void st_tx_wakeup(struct st_data_s *st_data)
465 {
466 	struct sk_buff *skb;
467 	unsigned long flags;	/* for irq save flags */
468 	pr_debug("%s", __func__);
469 	/* check for sending & set flag sending here */
470 	if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
471 		pr_debug("ST already sending");
472 		/* keep sending */
473 		set_bit(ST_TX_WAKEUP, &st_data->tx_state);
474 		return;
475 		/* TX_WAKEUP will be checked in another
476 		 * context
477 		 */
478 	}
479 	do {			/* come back if st_tx_wakeup is set */
480 		/* woke-up to write */
481 		clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
482 		while ((skb = st_int_dequeue(st_data))) {
483 			int len;
484 			spin_lock_irqsave(&st_data->lock, flags);
485 			/* enable wake-up from TTY */
486 			set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
487 			len = st_int_write(st_data, skb->data, skb->len);
488 			skb_pull(skb, len);
489 			/* if skb->len = len as expected, skb->len=0 */
490 			if (skb->len) {
491 				/* would be the next skb to be sent */
492 				st_data->tx_skb = skb;
493 				spin_unlock_irqrestore(&st_data->lock, flags);
494 				break;
495 			}
496 			dev_kfree_skb_irq(skb);
497 			spin_unlock_irqrestore(&st_data->lock, flags);
498 		}
499 		/* if wake-up is set in another context- restart sending */
500 	} while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
501 
502 	/* clear flag sending */
503 	clear_bit(ST_TX_SENDING, &st_data->tx_state);
504 }
505 
506 /********************************************************************/
507 /* functions called from ST KIM
508 */
kim_st_list_protocols(struct st_data_s * st_gdata,void * buf)509 void kim_st_list_protocols(struct st_data_s *st_gdata, void *buf)
510 {
511 	seq_printf(buf, "[%d]\nBT=%c\nFM=%c\nGPS=%c\n",
512 			st_gdata->protos_registered,
513 			st_gdata->is_registered[0x04] == true ? 'R' : 'U',
514 			st_gdata->is_registered[0x08] == true ? 'R' : 'U',
515 			st_gdata->is_registered[0x09] == true ? 'R' : 'U');
516 }
517 
518 /********************************************************************/
519 /*
520  * functions called from protocol stack drivers
521  * to be EXPORT-ed
522  */
st_register(struct st_proto_s * new_proto)523 long st_register(struct st_proto_s *new_proto)
524 {
525 	struct st_data_s	*st_gdata;
526 	long err = 0;
527 	unsigned long flags = 0;
528 
529 	st_kim_ref(&st_gdata, 0);
530 	if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
531 	    || new_proto->reg_complete_cb == NULL) {
532 		pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
533 		return -EINVAL;
534 	}
535 
536 	if (new_proto->chnl_id >= ST_MAX_CHANNELS) {
537 		pr_err("chnl_id %d not supported", new_proto->chnl_id);
538 		return -EPROTONOSUPPORT;
539 	}
540 
541 	if (st_gdata->is_registered[new_proto->chnl_id] == true) {
542 		pr_err("chnl_id %d already registered", new_proto->chnl_id);
543 		return -EALREADY;
544 	}
545 
546 	/* can be from process context only */
547 	spin_lock_irqsave(&st_gdata->lock, flags);
548 
549 	if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
550 		pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->chnl_id);
551 		/* fw download in progress */
552 
553 		add_channel_to_table(st_gdata, new_proto);
554 		st_gdata->protos_registered++;
555 		new_proto->write = st_write;
556 
557 		set_bit(ST_REG_PENDING, &st_gdata->st_state);
558 		spin_unlock_irqrestore(&st_gdata->lock, flags);
559 		return -EINPROGRESS;
560 	} else if (st_gdata->protos_registered == ST_EMPTY) {
561 		pr_info(" chnl_id list empty :%d ", new_proto->chnl_id);
562 		set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
563 		st_recv = st_kim_recv;
564 
565 		/* enable the ST LL - to set default chip state */
566 		st_ll_enable(st_gdata);
567 
568 		/* release lock previously held - re-locked below */
569 		spin_unlock_irqrestore(&st_gdata->lock, flags);
570 
571 		/*
572 		 * this may take a while to complete
573 		 * since it involves BT fw download
574 		 */
575 		err = st_kim_start(st_gdata->kim_data);
576 		if (err != 0) {
577 			clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
578 			if ((st_gdata->protos_registered != ST_EMPTY) &&
579 			    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
580 				pr_err(" KIM failure complete callback ");
581 				spin_lock_irqsave(&st_gdata->lock, flags);
582 				st_reg_complete(st_gdata, err);
583 				spin_unlock_irqrestore(&st_gdata->lock, flags);
584 				clear_bit(ST_REG_PENDING, &st_gdata->st_state);
585 			}
586 			return -EINVAL;
587 		}
588 
589 		spin_lock_irqsave(&st_gdata->lock, flags);
590 
591 		clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
592 		st_recv = st_int_recv;
593 
594 		/*
595 		 * this is where all pending registration
596 		 * are signalled to be complete by calling callback functions
597 		 */
598 		if ((st_gdata->protos_registered != ST_EMPTY) &&
599 		    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
600 			pr_debug(" call reg complete callback ");
601 			st_reg_complete(st_gdata, 0);
602 		}
603 		clear_bit(ST_REG_PENDING, &st_gdata->st_state);
604 
605 		/*
606 		 * check for already registered once more,
607 		 * since the above check is old
608 		 */
609 		if (st_gdata->is_registered[new_proto->chnl_id] == true) {
610 			pr_err(" proto %d already registered ",
611 				   new_proto->chnl_id);
612 			spin_unlock_irqrestore(&st_gdata->lock, flags);
613 			return -EALREADY;
614 		}
615 
616 		add_channel_to_table(st_gdata, new_proto);
617 		st_gdata->protos_registered++;
618 		new_proto->write = st_write;
619 		spin_unlock_irqrestore(&st_gdata->lock, flags);
620 		return err;
621 	}
622 	/* if fw is already downloaded & new stack registers protocol */
623 	else {
624 		add_channel_to_table(st_gdata, new_proto);
625 		st_gdata->protos_registered++;
626 		new_proto->write = st_write;
627 
628 		/* lock already held before entering else */
629 		spin_unlock_irqrestore(&st_gdata->lock, flags);
630 		return err;
631 	}
632 }
633 EXPORT_SYMBOL_GPL(st_register);
634 
635 /*
636  * to unregister a protocol -
637  * to be called from protocol stack driver
638  */
st_unregister(struct st_proto_s * proto)639 long st_unregister(struct st_proto_s *proto)
640 {
641 	long err = 0;
642 	unsigned long flags = 0;
643 	struct st_data_s	*st_gdata;
644 
645 	pr_debug("%s: %d ", __func__, proto->chnl_id);
646 
647 	st_kim_ref(&st_gdata, 0);
648 	if (!st_gdata || proto->chnl_id >= ST_MAX_CHANNELS) {
649 		pr_err(" chnl_id %d not supported", proto->chnl_id);
650 		return -EPROTONOSUPPORT;
651 	}
652 
653 	spin_lock_irqsave(&st_gdata->lock, flags);
654 
655 	if (st_gdata->is_registered[proto->chnl_id] == false) {
656 		pr_err(" chnl_id %d not registered", proto->chnl_id);
657 		spin_unlock_irqrestore(&st_gdata->lock, flags);
658 		return -EPROTONOSUPPORT;
659 	}
660 
661 	if (st_gdata->protos_registered)
662 		st_gdata->protos_registered--;
663 
664 	remove_channel_from_table(st_gdata, proto);
665 	spin_unlock_irqrestore(&st_gdata->lock, flags);
666 
667 	if ((st_gdata->protos_registered == ST_EMPTY) &&
668 	    (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
669 		pr_info(" all chnl_ids unregistered ");
670 
671 		/* stop traffic on tty */
672 		if (st_gdata->tty) {
673 			tty_ldisc_flush(st_gdata->tty);
674 			stop_tty(st_gdata->tty);
675 		}
676 
677 		/* all chnl_ids now unregistered */
678 		st_kim_stop(st_gdata->kim_data);
679 		/* disable ST LL */
680 		st_ll_disable(st_gdata);
681 	}
682 	return err;
683 }
684 
685 /*
686  * called in protocol stack drivers
687  * via the write function pointer
688  */
st_write(struct sk_buff * skb)689 long st_write(struct sk_buff *skb)
690 {
691 	struct st_data_s *st_gdata;
692 	long len;
693 
694 	st_kim_ref(&st_gdata, 0);
695 	if (unlikely(skb == NULL || st_gdata == NULL
696 		|| st_gdata->tty == NULL)) {
697 		pr_err("data/tty unavailable to perform write");
698 		return -EINVAL;
699 	}
700 
701 	pr_debug("%d to be written", skb->len);
702 	len = skb->len;
703 
704 	/* st_ll to decide where to enqueue the skb */
705 	st_int_enqueue(st_gdata, skb);
706 	/* wake up */
707 	st_tx_wakeup(st_gdata);
708 
709 	/* return number of bytes written */
710 	return len;
711 }
712 
713 /* for protocols making use of shared transport */
714 EXPORT_SYMBOL_GPL(st_unregister);
715 
716 /********************************************************************/
717 /*
718  * functions called from TTY layer
719  */
st_tty_open(struct tty_struct * tty)720 static int st_tty_open(struct tty_struct *tty)
721 {
722 	struct st_data_s *st_gdata;
723 	pr_info("%s ", __func__);
724 
725 	st_kim_ref(&st_gdata, 0);
726 	st_gdata->tty = tty;
727 	tty->disc_data = st_gdata;
728 
729 	/* don't do an wakeup for now */
730 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
731 
732 	/* mem already allocated
733 	 */
734 	tty->receive_room = 65536;
735 	/* Flush any pending characters in the driver and discipline. */
736 	tty_ldisc_flush(tty);
737 	tty_driver_flush_buffer(tty);
738 	/*
739 	 * signal to UIM via KIM that -
740 	 * installation of N_TI_WL ldisc is complete
741 	 */
742 	st_kim_complete(st_gdata->kim_data);
743 	pr_debug("done %s", __func__);
744 
745 	return 0;
746 }
747 
st_tty_close(struct tty_struct * tty)748 static void st_tty_close(struct tty_struct *tty)
749 {
750 	unsigned char i;
751 	unsigned long flags;
752 	struct	st_data_s *st_gdata = tty->disc_data;
753 
754 	pr_info("%s ", __func__);
755 
756 	/*
757 	 * TODO:
758 	 * if a protocol has been registered & line discipline
759 	 * un-installed for some reason - what should be done ?
760 	 */
761 	spin_lock_irqsave(&st_gdata->lock, flags);
762 	for (i = ST_BT; i < ST_MAX_CHANNELS; i++) {
763 		if (st_gdata->is_registered[i] == true)
764 			pr_err("%d not un-registered", i);
765 		st_gdata->list[i] = NULL;
766 		st_gdata->is_registered[i] = false;
767 	}
768 	st_gdata->protos_registered = 0;
769 	spin_unlock_irqrestore(&st_gdata->lock, flags);
770 	/*
771 	 * signal to UIM via KIM that -
772 	 * N_TI_WL ldisc is un-installed
773 	 */
774 	st_kim_complete(st_gdata->kim_data);
775 	st_gdata->tty = NULL;
776 	/* Flush any pending characters in the driver and discipline. */
777 	tty_ldisc_flush(tty);
778 	tty_driver_flush_buffer(tty);
779 
780 	spin_lock_irqsave(&st_gdata->lock, flags);
781 	/* empty out txq and tx_waitq */
782 	skb_queue_purge(&st_gdata->txq);
783 	skb_queue_purge(&st_gdata->tx_waitq);
784 	/* reset the TTY Rx states of ST */
785 	st_gdata->rx_count = 0;
786 	st_gdata->rx_state = ST_W4_PACKET_TYPE;
787 	kfree_skb(st_gdata->rx_skb);
788 	st_gdata->rx_skb = NULL;
789 	spin_unlock_irqrestore(&st_gdata->lock, flags);
790 
791 	pr_debug("%s: done ", __func__);
792 }
793 
st_tty_receive(struct tty_struct * tty,const u8 * data,const u8 * tty_flags,size_t count)794 static void st_tty_receive(struct tty_struct *tty, const u8 *data,
795 			   const u8 *tty_flags, size_t count)
796 {
797 #ifdef VERBOSE
798 	print_hex_dump(KERN_DEBUG, ">in>", DUMP_PREFIX_NONE,
799 		16, 1, data, count, 0);
800 #endif
801 
802 	/*
803 	 * if fw download is in progress then route incoming data
804 	 * to KIM for validation
805 	 */
806 	st_recv(tty->disc_data, data, count);
807 	pr_debug("done %s", __func__);
808 }
809 
810 /*
811  * wake-up function called in from the TTY layer
812  * inside the internal wakeup function will be called
813  */
st_tty_wakeup(struct tty_struct * tty)814 static void st_tty_wakeup(struct tty_struct *tty)
815 {
816 	struct	st_data_s *st_gdata = tty->disc_data;
817 	pr_debug("%s ", __func__);
818 	/* don't do an wakeup for now */
819 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
820 
821 	/*
822 	 * schedule the internal wakeup instead of calling directly to
823 	 * avoid lockup (port->lock needed in tty->ops->write is
824 	 * already taken here
825 	 */
826 	schedule_work(&st_gdata->work_write_wakeup);
827 }
828 
st_tty_flush_buffer(struct tty_struct * tty)829 static void st_tty_flush_buffer(struct tty_struct *tty)
830 {
831 	struct	st_data_s *st_gdata = tty->disc_data;
832 	pr_debug("%s ", __func__);
833 
834 	kfree_skb(st_gdata->tx_skb);
835 	st_gdata->tx_skb = NULL;
836 
837 	tty_driver_flush_buffer(tty);
838 	return;
839 }
840 
841 static struct tty_ldisc_ops st_ldisc_ops = {
842 	.num = N_TI_WL,
843 	.name = "n_st",
844 	.open = st_tty_open,
845 	.close = st_tty_close,
846 	.receive_buf = st_tty_receive,
847 	.write_wakeup = st_tty_wakeup,
848 	.flush_buffer = st_tty_flush_buffer,
849 	.owner = THIS_MODULE
850 };
851 
852 /********************************************************************/
st_core_init(struct st_data_s ** core_data)853 int st_core_init(struct st_data_s **core_data)
854 {
855 	struct st_data_s *st_gdata;
856 	long err;
857 
858 	err = tty_register_ldisc(&st_ldisc_ops);
859 	if (err) {
860 		pr_err("error registering %d line discipline %ld",
861 			   N_TI_WL, err);
862 		return err;
863 	}
864 	pr_debug("registered n_shared line discipline");
865 
866 	st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
867 	if (!st_gdata) {
868 		pr_err("memory allocation failed");
869 		err = -ENOMEM;
870 		goto err_unreg_ldisc;
871 	}
872 
873 	/* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
874 	 * will be pushed in this queue for actual transmission.
875 	 */
876 	skb_queue_head_init(&st_gdata->txq);
877 	skb_queue_head_init(&st_gdata->tx_waitq);
878 
879 	/* Locking used in st_int_enqueue() to avoid multiple execution */
880 	spin_lock_init(&st_gdata->lock);
881 
882 	err = st_ll_init(st_gdata);
883 	if (err) {
884 		pr_err("error during st_ll initialization(%ld)", err);
885 		goto err_free_gdata;
886 	}
887 
888 	INIT_WORK(&st_gdata->work_write_wakeup, work_fn_write_wakeup);
889 
890 	*core_data = st_gdata;
891 	return 0;
892 err_free_gdata:
893 	kfree(st_gdata);
894 err_unreg_ldisc:
895 	tty_unregister_ldisc(&st_ldisc_ops);
896 	return err;
897 }
898 
st_core_exit(struct st_data_s * st_gdata)899 void st_core_exit(struct st_data_s *st_gdata)
900 {
901 	long err;
902 	/* internal module cleanup */
903 	err = st_ll_deinit(st_gdata);
904 	if (err)
905 		pr_err("error during deinit of ST LL %ld", err);
906 
907 	if (st_gdata != NULL) {
908 		/* Free ST Tx Qs and skbs */
909 		skb_queue_purge(&st_gdata->txq);
910 		skb_queue_purge(&st_gdata->tx_waitq);
911 		kfree_skb(st_gdata->rx_skb);
912 		kfree_skb(st_gdata->tx_skb);
913 		/* TTY ldisc cleanup */
914 		tty_unregister_ldisc(&st_ldisc_ops);
915 		/* free the global data pointer */
916 		kfree(st_gdata);
917 	}
918 }
919