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1 /*
2  * Driver for the Diolan DLN-2 USB adapter
3  *
4  * Copyright (c) 2014 Intel Corporation
5  *
6  * Derived from:
7  *  i2c-diolan-u2c.c
8  *  Copyright (c) 2010-2011 Ericsson AB
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation, version 2.
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/slab.h>
19 #include <linux/usb.h>
20 #include <linux/i2c.h>
21 #include <linux/mutex.h>
22 #include <linux/platform_device.h>
23 #include <linux/mfd/core.h>
24 #include <linux/mfd/dln2.h>
25 #include <linux/rculist.h>
26 
27 struct dln2_header {
28 	__le16 size;
29 	__le16 id;
30 	__le16 echo;
31 	__le16 handle;
32 };
33 
34 struct dln2_response {
35 	struct dln2_header hdr;
36 	__le16 result;
37 };
38 
39 #define DLN2_GENERIC_MODULE_ID		0x00
40 #define DLN2_GENERIC_CMD(cmd)		DLN2_CMD(cmd, DLN2_GENERIC_MODULE_ID)
41 #define CMD_GET_DEVICE_VER		DLN2_GENERIC_CMD(0x30)
42 #define CMD_GET_DEVICE_SN		DLN2_GENERIC_CMD(0x31)
43 
44 #define DLN2_HW_ID			0x200
45 #define DLN2_USB_TIMEOUT		200	/* in ms */
46 #define DLN2_MAX_RX_SLOTS		16
47 #define DLN2_MAX_URBS			16
48 #define DLN2_RX_BUF_SIZE		512
49 
50 enum dln2_handle {
51 	DLN2_HANDLE_EVENT = 0,		/* don't change, hardware defined */
52 	DLN2_HANDLE_CTRL,
53 	DLN2_HANDLE_GPIO,
54 	DLN2_HANDLE_I2C,
55 	DLN2_HANDLE_SPI,
56 	DLN2_HANDLES
57 };
58 
59 /*
60  * Receive context used between the receive demultiplexer and the transfer
61  * routine. While sending a request the transfer routine will look for a free
62  * receive context and use it to wait for a response and to receive the URB and
63  * thus the response data.
64  */
65 struct dln2_rx_context {
66 	/* completion used to wait for a response */
67 	struct completion done;
68 
69 	/* if non-NULL the URB contains the response */
70 	struct urb *urb;
71 
72 	/* if true then this context is used to wait for a response */
73 	bool in_use;
74 };
75 
76 /*
77  * Receive contexts for a particular DLN2 module (i2c, gpio, etc.). We use the
78  * handle header field to identify the module in dln2_dev.mod_rx_slots and then
79  * the echo header field to index the slots field and find the receive context
80  * for a particular request.
81  */
82 struct dln2_mod_rx_slots {
83 	/* RX slots bitmap */
84 	DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS);
85 
86 	/* used to wait for a free RX slot */
87 	wait_queue_head_t wq;
88 
89 	/* used to wait for an RX operation to complete */
90 	struct dln2_rx_context slots[DLN2_MAX_RX_SLOTS];
91 
92 	/* avoid races between alloc/free_rx_slot and dln2_rx_transfer */
93 	spinlock_t lock;
94 };
95 
96 enum dln2_endpoint {
97 	DLN2_EP_OUT	= 0,
98 	DLN2_EP_IN	= 1,
99 };
100 
101 struct dln2_dev {
102 	struct usb_device *usb_dev;
103 	struct usb_interface *interface;
104 	u8 ep_in;
105 	u8 ep_out;
106 
107 	struct urb *rx_urb[DLN2_MAX_URBS];
108 	void *rx_buf[DLN2_MAX_URBS];
109 
110 	struct dln2_mod_rx_slots mod_rx_slots[DLN2_HANDLES];
111 
112 	struct list_head event_cb_list;
113 	spinlock_t event_cb_lock;
114 
115 	bool disconnect;
116 	int active_transfers;
117 	wait_queue_head_t disconnect_wq;
118 	spinlock_t disconnect_lock;
119 };
120 
121 struct dln2_event_cb_entry {
122 	struct list_head list;
123 	u16 id;
124 	struct platform_device *pdev;
125 	dln2_event_cb_t callback;
126 };
127 
dln2_register_event_cb(struct platform_device * pdev,u16 id,dln2_event_cb_t event_cb)128 int dln2_register_event_cb(struct platform_device *pdev, u16 id,
129 			   dln2_event_cb_t event_cb)
130 {
131 	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
132 	struct dln2_event_cb_entry *i, *entry;
133 	unsigned long flags;
134 	int ret = 0;
135 
136 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
137 	if (!entry)
138 		return -ENOMEM;
139 
140 	entry->id = id;
141 	entry->callback = event_cb;
142 	entry->pdev = pdev;
143 
144 	spin_lock_irqsave(&dln2->event_cb_lock, flags);
145 
146 	list_for_each_entry(i, &dln2->event_cb_list, list) {
147 		if (i->id == id) {
148 			ret = -EBUSY;
149 			break;
150 		}
151 	}
152 
153 	if (!ret)
154 		list_add_rcu(&entry->list, &dln2->event_cb_list);
155 
156 	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
157 
158 	if (ret)
159 		kfree(entry);
160 
161 	return ret;
162 }
163 EXPORT_SYMBOL(dln2_register_event_cb);
164 
dln2_unregister_event_cb(struct platform_device * pdev,u16 id)165 void dln2_unregister_event_cb(struct platform_device *pdev, u16 id)
166 {
167 	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
168 	struct dln2_event_cb_entry *i;
169 	unsigned long flags;
170 	bool found = false;
171 
172 	spin_lock_irqsave(&dln2->event_cb_lock, flags);
173 
174 	list_for_each_entry(i, &dln2->event_cb_list, list) {
175 		if (i->id == id) {
176 			list_del_rcu(&i->list);
177 			found = true;
178 			break;
179 		}
180 	}
181 
182 	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
183 
184 	if (found) {
185 		synchronize_rcu();
186 		kfree(i);
187 	}
188 }
189 EXPORT_SYMBOL(dln2_unregister_event_cb);
190 
191 /*
192  * Returns true if a valid transfer slot is found. In this case the URB must not
193  * be resubmitted immediately in dln2_rx as we need the data when dln2_transfer
194  * is woke up. It will be resubmitted there.
195  */
dln2_transfer_complete(struct dln2_dev * dln2,struct urb * urb,u16 handle,u16 rx_slot)196 static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
197 				   u16 handle, u16 rx_slot)
198 {
199 	struct device *dev = &dln2->interface->dev;
200 	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
201 	struct dln2_rx_context *rxc;
202 	unsigned long flags;
203 	bool valid_slot = false;
204 
205 	if (rx_slot >= DLN2_MAX_RX_SLOTS)
206 		goto out;
207 
208 	rxc = &rxs->slots[rx_slot];
209 
210 	spin_lock_irqsave(&rxs->lock, flags);
211 	if (rxc->in_use && !rxc->urb) {
212 		rxc->urb = urb;
213 		complete(&rxc->done);
214 		valid_slot = true;
215 	}
216 	spin_unlock_irqrestore(&rxs->lock, flags);
217 
218 out:
219 	if (!valid_slot)
220 		dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);
221 
222 	return valid_slot;
223 }
224 
dln2_run_event_callbacks(struct dln2_dev * dln2,u16 id,u16 echo,void * data,int len)225 static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
226 				     void *data, int len)
227 {
228 	struct dln2_event_cb_entry *i;
229 
230 	rcu_read_lock();
231 
232 	list_for_each_entry_rcu(i, &dln2->event_cb_list, list) {
233 		if (i->id == id) {
234 			i->callback(i->pdev, echo, data, len);
235 			break;
236 		}
237 	}
238 
239 	rcu_read_unlock();
240 }
241 
dln2_rx(struct urb * urb)242 static void dln2_rx(struct urb *urb)
243 {
244 	struct dln2_dev *dln2 = urb->context;
245 	struct dln2_header *hdr = urb->transfer_buffer;
246 	struct device *dev = &dln2->interface->dev;
247 	u16 id, echo, handle, size;
248 	u8 *data;
249 	int len;
250 	int err;
251 
252 	switch (urb->status) {
253 	case 0:
254 		/* success */
255 		break;
256 	case -ECONNRESET:
257 	case -ENOENT:
258 	case -ESHUTDOWN:
259 	case -EPIPE:
260 		/* this urb is terminated, clean up */
261 		dev_dbg(dev, "urb shutting down with status %d\n", urb->status);
262 		return;
263 	default:
264 		dev_dbg(dev, "nonzero urb status received %d\n", urb->status);
265 		goto out;
266 	}
267 
268 	if (urb->actual_length < sizeof(struct dln2_header)) {
269 		dev_err(dev, "short response: %d\n", urb->actual_length);
270 		goto out;
271 	}
272 
273 	handle = le16_to_cpu(hdr->handle);
274 	id = le16_to_cpu(hdr->id);
275 	echo = le16_to_cpu(hdr->echo);
276 	size = le16_to_cpu(hdr->size);
277 
278 	if (size != urb->actual_length) {
279 		dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n",
280 			handle, id, echo, size, urb->actual_length);
281 		goto out;
282 	}
283 
284 	if (handle >= DLN2_HANDLES) {
285 		dev_warn(dev, "invalid handle %d\n", handle);
286 		goto out;
287 	}
288 
289 	data = urb->transfer_buffer + sizeof(struct dln2_header);
290 	len = urb->actual_length - sizeof(struct dln2_header);
291 
292 	if (handle == DLN2_HANDLE_EVENT) {
293 		unsigned long flags;
294 
295 		spin_lock_irqsave(&dln2->event_cb_lock, flags);
296 		dln2_run_event_callbacks(dln2, id, echo, data, len);
297 		spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
298 	} else {
299 		/* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
300 		if (dln2_transfer_complete(dln2, urb, handle, echo))
301 			return;
302 	}
303 
304 out:
305 	err = usb_submit_urb(urb, GFP_ATOMIC);
306 	if (err < 0)
307 		dev_err(dev, "failed to resubmit RX URB: %d\n", err);
308 }
309 
dln2_prep_buf(u16 handle,u16 cmd,u16 echo,const void * obuf,int * obuf_len,gfp_t gfp)310 static void *dln2_prep_buf(u16 handle, u16 cmd, u16 echo, const void *obuf,
311 			   int *obuf_len, gfp_t gfp)
312 {
313 	int len;
314 	void *buf;
315 	struct dln2_header *hdr;
316 
317 	len = *obuf_len + sizeof(*hdr);
318 	buf = kmalloc(len, gfp);
319 	if (!buf)
320 		return NULL;
321 
322 	hdr = (struct dln2_header *)buf;
323 	hdr->id = cpu_to_le16(cmd);
324 	hdr->size = cpu_to_le16(len);
325 	hdr->echo = cpu_to_le16(echo);
326 	hdr->handle = cpu_to_le16(handle);
327 
328 	memcpy(buf + sizeof(*hdr), obuf, *obuf_len);
329 
330 	*obuf_len = len;
331 
332 	return buf;
333 }
334 
dln2_send_wait(struct dln2_dev * dln2,u16 handle,u16 cmd,u16 echo,const void * obuf,int obuf_len)335 static int dln2_send_wait(struct dln2_dev *dln2, u16 handle, u16 cmd, u16 echo,
336 			  const void *obuf, int obuf_len)
337 {
338 	int ret = 0;
339 	int len = obuf_len;
340 	void *buf;
341 	int actual;
342 
343 	buf = dln2_prep_buf(handle, cmd, echo, obuf, &len, GFP_KERNEL);
344 	if (!buf)
345 		return -ENOMEM;
346 
347 	ret = usb_bulk_msg(dln2->usb_dev,
348 			   usb_sndbulkpipe(dln2->usb_dev, dln2->ep_out),
349 			   buf, len, &actual, DLN2_USB_TIMEOUT);
350 
351 	kfree(buf);
352 
353 	return ret;
354 }
355 
find_free_slot(struct dln2_dev * dln2,u16 handle,int * slot)356 static bool find_free_slot(struct dln2_dev *dln2, u16 handle, int *slot)
357 {
358 	struct dln2_mod_rx_slots *rxs;
359 	unsigned long flags;
360 
361 	if (dln2->disconnect) {
362 		*slot = -ENODEV;
363 		return true;
364 	}
365 
366 	rxs = &dln2->mod_rx_slots[handle];
367 
368 	spin_lock_irqsave(&rxs->lock, flags);
369 
370 	*slot = find_first_zero_bit(rxs->bmap, DLN2_MAX_RX_SLOTS);
371 
372 	if (*slot < DLN2_MAX_RX_SLOTS) {
373 		struct dln2_rx_context *rxc = &rxs->slots[*slot];
374 
375 		set_bit(*slot, rxs->bmap);
376 		rxc->in_use = true;
377 	}
378 
379 	spin_unlock_irqrestore(&rxs->lock, flags);
380 
381 	return *slot < DLN2_MAX_RX_SLOTS;
382 }
383 
alloc_rx_slot(struct dln2_dev * dln2,u16 handle)384 static int alloc_rx_slot(struct dln2_dev *dln2, u16 handle)
385 {
386 	int ret;
387 	int slot;
388 
389 	/*
390 	 * No need to timeout here, the wait is bounded by the timeout in
391 	 * _dln2_transfer.
392 	 */
393 	ret = wait_event_interruptible(dln2->mod_rx_slots[handle].wq,
394 				       find_free_slot(dln2, handle, &slot));
395 	if (ret < 0)
396 		return ret;
397 
398 	return slot;
399 }
400 
free_rx_slot(struct dln2_dev * dln2,u16 handle,int slot)401 static void free_rx_slot(struct dln2_dev *dln2, u16 handle, int slot)
402 {
403 	struct dln2_mod_rx_slots *rxs;
404 	struct urb *urb = NULL;
405 	unsigned long flags;
406 	struct dln2_rx_context *rxc;
407 
408 	rxs = &dln2->mod_rx_slots[handle];
409 
410 	spin_lock_irqsave(&rxs->lock, flags);
411 
412 	clear_bit(slot, rxs->bmap);
413 
414 	rxc = &rxs->slots[slot];
415 	rxc->in_use = false;
416 	urb = rxc->urb;
417 	rxc->urb = NULL;
418 	reinit_completion(&rxc->done);
419 
420 	spin_unlock_irqrestore(&rxs->lock, flags);
421 
422 	if (urb) {
423 		int err;
424 		struct device *dev = &dln2->interface->dev;
425 
426 		err = usb_submit_urb(urb, GFP_KERNEL);
427 		if (err < 0)
428 			dev_err(dev, "failed to resubmit RX URB: %d\n", err);
429 	}
430 
431 	wake_up_interruptible(&rxs->wq);
432 }
433 
_dln2_transfer(struct dln2_dev * dln2,u16 handle,u16 cmd,const void * obuf,unsigned obuf_len,void * ibuf,unsigned * ibuf_len)434 static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
435 			  const void *obuf, unsigned obuf_len,
436 			  void *ibuf, unsigned *ibuf_len)
437 {
438 	int ret = 0;
439 	int rx_slot;
440 	struct dln2_response *rsp;
441 	struct dln2_rx_context *rxc;
442 	struct device *dev = &dln2->interface->dev;
443 	const unsigned long timeout = msecs_to_jiffies(DLN2_USB_TIMEOUT);
444 	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
445 	int size;
446 
447 	spin_lock(&dln2->disconnect_lock);
448 	if (!dln2->disconnect)
449 		dln2->active_transfers++;
450 	else
451 		ret = -ENODEV;
452 	spin_unlock(&dln2->disconnect_lock);
453 
454 	if (ret)
455 		return ret;
456 
457 	rx_slot = alloc_rx_slot(dln2, handle);
458 	if (rx_slot < 0) {
459 		ret = rx_slot;
460 		goto out_decr;
461 	}
462 
463 	ret = dln2_send_wait(dln2, handle, cmd, rx_slot, obuf, obuf_len);
464 	if (ret < 0) {
465 		dev_err(dev, "USB write failed: %d\n", ret);
466 		goto out_free_rx_slot;
467 	}
468 
469 	rxc = &rxs->slots[rx_slot];
470 
471 	ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
472 	if (ret <= 0) {
473 		if (!ret)
474 			ret = -ETIMEDOUT;
475 		goto out_free_rx_slot;
476 	} else {
477 		ret = 0;
478 	}
479 
480 	if (dln2->disconnect) {
481 		ret = -ENODEV;
482 		goto out_free_rx_slot;
483 	}
484 
485 	/* if we got here we know that the response header has been checked */
486 	rsp = rxc->urb->transfer_buffer;
487 	size = le16_to_cpu(rsp->hdr.size);
488 
489 	if (size < sizeof(*rsp)) {
490 		ret = -EPROTO;
491 		goto out_free_rx_slot;
492 	}
493 
494 	if (le16_to_cpu(rsp->result) > 0x80) {
495 		dev_dbg(dev, "%d received response with error %d\n",
496 			handle, le16_to_cpu(rsp->result));
497 		ret = -EREMOTEIO;
498 		goto out_free_rx_slot;
499 	}
500 
501 	if (!ibuf)
502 		goto out_free_rx_slot;
503 
504 	if (*ibuf_len > size - sizeof(*rsp))
505 		*ibuf_len = size - sizeof(*rsp);
506 
507 	memcpy(ibuf, rsp + 1, *ibuf_len);
508 
509 out_free_rx_slot:
510 	free_rx_slot(dln2, handle, rx_slot);
511 out_decr:
512 	spin_lock(&dln2->disconnect_lock);
513 	dln2->active_transfers--;
514 	spin_unlock(&dln2->disconnect_lock);
515 	if (dln2->disconnect)
516 		wake_up(&dln2->disconnect_wq);
517 
518 	return ret;
519 }
520 
dln2_transfer(struct platform_device * pdev,u16 cmd,const void * obuf,unsigned obuf_len,void * ibuf,unsigned * ibuf_len)521 int dln2_transfer(struct platform_device *pdev, u16 cmd,
522 		  const void *obuf, unsigned obuf_len,
523 		  void *ibuf, unsigned *ibuf_len)
524 {
525 	struct dln2_platform_data *dln2_pdata;
526 	struct dln2_dev *dln2;
527 	u16 handle;
528 
529 	dln2 = dev_get_drvdata(pdev->dev.parent);
530 	dln2_pdata = dev_get_platdata(&pdev->dev);
531 	handle = dln2_pdata->handle;
532 
533 	return _dln2_transfer(dln2, handle, cmd, obuf, obuf_len, ibuf,
534 			      ibuf_len);
535 }
536 EXPORT_SYMBOL(dln2_transfer);
537 
dln2_check_hw(struct dln2_dev * dln2)538 static int dln2_check_hw(struct dln2_dev *dln2)
539 {
540 	int ret;
541 	__le32 hw_type;
542 	int len = sizeof(hw_type);
543 
544 	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_VER,
545 			     NULL, 0, &hw_type, &len);
546 	if (ret < 0)
547 		return ret;
548 	if (len < sizeof(hw_type))
549 		return -EREMOTEIO;
550 
551 	if (le32_to_cpu(hw_type) != DLN2_HW_ID) {
552 		dev_err(&dln2->interface->dev, "Device ID 0x%x not supported\n",
553 			le32_to_cpu(hw_type));
554 		return -ENODEV;
555 	}
556 
557 	return 0;
558 }
559 
dln2_print_serialno(struct dln2_dev * dln2)560 static int dln2_print_serialno(struct dln2_dev *dln2)
561 {
562 	int ret;
563 	__le32 serial_no;
564 	int len = sizeof(serial_no);
565 	struct device *dev = &dln2->interface->dev;
566 
567 	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
568 			     &serial_no, &len);
569 	if (ret < 0)
570 		return ret;
571 	if (len < sizeof(serial_no))
572 		return -EREMOTEIO;
573 
574 	dev_info(dev, "Diolan DLN2 serial %u\n", le32_to_cpu(serial_no));
575 
576 	return 0;
577 }
578 
dln2_hw_init(struct dln2_dev * dln2)579 static int dln2_hw_init(struct dln2_dev *dln2)
580 {
581 	int ret;
582 
583 	ret = dln2_check_hw(dln2);
584 	if (ret < 0)
585 		return ret;
586 
587 	return dln2_print_serialno(dln2);
588 }
589 
dln2_free_rx_urbs(struct dln2_dev * dln2)590 static void dln2_free_rx_urbs(struct dln2_dev *dln2)
591 {
592 	int i;
593 
594 	for (i = 0; i < DLN2_MAX_URBS; i++) {
595 		usb_free_urb(dln2->rx_urb[i]);
596 		kfree(dln2->rx_buf[i]);
597 	}
598 }
599 
dln2_stop_rx_urbs(struct dln2_dev * dln2)600 static void dln2_stop_rx_urbs(struct dln2_dev *dln2)
601 {
602 	int i;
603 
604 	for (i = 0; i < DLN2_MAX_URBS; i++)
605 		usb_kill_urb(dln2->rx_urb[i]);
606 }
607 
dln2_free(struct dln2_dev * dln2)608 static void dln2_free(struct dln2_dev *dln2)
609 {
610 	dln2_free_rx_urbs(dln2);
611 	usb_put_dev(dln2->usb_dev);
612 	kfree(dln2);
613 }
614 
dln2_setup_rx_urbs(struct dln2_dev * dln2,struct usb_host_interface * hostif)615 static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
616 			      struct usb_host_interface *hostif)
617 {
618 	int i;
619 	const int rx_max_size = DLN2_RX_BUF_SIZE;
620 
621 	for (i = 0; i < DLN2_MAX_URBS; i++) {
622 		dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
623 		if (!dln2->rx_buf[i])
624 			return -ENOMEM;
625 
626 		dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
627 		if (!dln2->rx_urb[i])
628 			return -ENOMEM;
629 
630 		usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev,
631 				  usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in),
632 				  dln2->rx_buf[i], rx_max_size, dln2_rx, dln2);
633 	}
634 
635 	return 0;
636 }
637 
dln2_start_rx_urbs(struct dln2_dev * dln2,gfp_t gfp)638 static int dln2_start_rx_urbs(struct dln2_dev *dln2, gfp_t gfp)
639 {
640 	struct device *dev = &dln2->interface->dev;
641 	int ret;
642 	int i;
643 
644 	for (i = 0; i < DLN2_MAX_URBS; i++) {
645 		ret = usb_submit_urb(dln2->rx_urb[i], gfp);
646 		if (ret < 0) {
647 			dev_err(dev, "failed to submit RX URB: %d\n", ret);
648 			return ret;
649 		}
650 	}
651 
652 	return 0;
653 }
654 
655 static struct dln2_platform_data dln2_pdata_gpio = {
656 	.handle = DLN2_HANDLE_GPIO,
657 };
658 
659 /* Only one I2C port seems to be supported on current hardware */
660 static struct dln2_platform_data dln2_pdata_i2c = {
661 	.handle = DLN2_HANDLE_I2C,
662 	.port = 0,
663 };
664 
665 /* Only one SPI port supported */
666 static struct dln2_platform_data dln2_pdata_spi = {
667 	.handle = DLN2_HANDLE_SPI,
668 	.port = 0,
669 };
670 
671 static const struct mfd_cell dln2_devs[] = {
672 	{
673 		.name = "dln2-gpio",
674 		.platform_data = &dln2_pdata_gpio,
675 		.pdata_size = sizeof(struct dln2_platform_data),
676 	},
677 	{
678 		.name = "dln2-i2c",
679 		.platform_data = &dln2_pdata_i2c,
680 		.pdata_size = sizeof(struct dln2_platform_data),
681 	},
682 	{
683 		.name = "dln2-spi",
684 		.platform_data = &dln2_pdata_spi,
685 		.pdata_size = sizeof(struct dln2_platform_data),
686 	},
687 };
688 
dln2_stop(struct dln2_dev * dln2)689 static void dln2_stop(struct dln2_dev *dln2)
690 {
691 	int i, j;
692 
693 	/* don't allow starting new transfers */
694 	spin_lock(&dln2->disconnect_lock);
695 	dln2->disconnect = true;
696 	spin_unlock(&dln2->disconnect_lock);
697 
698 	/* cancel in progress transfers */
699 	for (i = 0; i < DLN2_HANDLES; i++) {
700 		struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[i];
701 		unsigned long flags;
702 
703 		spin_lock_irqsave(&rxs->lock, flags);
704 
705 		/* cancel all response waiters */
706 		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) {
707 			struct dln2_rx_context *rxc = &rxs->slots[j];
708 
709 			if (rxc->in_use)
710 				complete(&rxc->done);
711 		}
712 
713 		spin_unlock_irqrestore(&rxs->lock, flags);
714 	}
715 
716 	/* wait for transfers to end */
717 	wait_event(dln2->disconnect_wq, !dln2->active_transfers);
718 
719 	dln2_stop_rx_urbs(dln2);
720 }
721 
dln2_disconnect(struct usb_interface * interface)722 static void dln2_disconnect(struct usb_interface *interface)
723 {
724 	struct dln2_dev *dln2 = usb_get_intfdata(interface);
725 
726 	dln2_stop(dln2);
727 
728 	mfd_remove_devices(&interface->dev);
729 
730 	dln2_free(dln2);
731 }
732 
dln2_probe(struct usb_interface * interface,const struct usb_device_id * usb_id)733 static int dln2_probe(struct usb_interface *interface,
734 		      const struct usb_device_id *usb_id)
735 {
736 	struct usb_host_interface *hostif = interface->cur_altsetting;
737 	struct usb_endpoint_descriptor *epin;
738 	struct usb_endpoint_descriptor *epout;
739 	struct device *dev = &interface->dev;
740 	struct dln2_dev *dln2;
741 	int ret;
742 	int i, j;
743 
744 	if (hostif->desc.bInterfaceNumber != 0 ||
745 	    hostif->desc.bNumEndpoints < 2)
746 		return -ENODEV;
747 
748 	epout = &hostif->endpoint[DLN2_EP_OUT].desc;
749 	if (!usb_endpoint_is_bulk_out(epout))
750 		return -ENODEV;
751 	epin = &hostif->endpoint[DLN2_EP_IN].desc;
752 	if (!usb_endpoint_is_bulk_in(epin))
753 		return -ENODEV;
754 
755 	dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
756 	if (!dln2)
757 		return -ENOMEM;
758 
759 	dln2->ep_out = epout->bEndpointAddress;
760 	dln2->ep_in = epin->bEndpointAddress;
761 	dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
762 	dln2->interface = interface;
763 	usb_set_intfdata(interface, dln2);
764 	init_waitqueue_head(&dln2->disconnect_wq);
765 
766 	for (i = 0; i < DLN2_HANDLES; i++) {
767 		init_waitqueue_head(&dln2->mod_rx_slots[i].wq);
768 		spin_lock_init(&dln2->mod_rx_slots[i].lock);
769 		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++)
770 			init_completion(&dln2->mod_rx_slots[i].slots[j].done);
771 	}
772 
773 	spin_lock_init(&dln2->event_cb_lock);
774 	spin_lock_init(&dln2->disconnect_lock);
775 	INIT_LIST_HEAD(&dln2->event_cb_list);
776 
777 	ret = dln2_setup_rx_urbs(dln2, hostif);
778 	if (ret)
779 		goto out_free;
780 
781 	ret = dln2_start_rx_urbs(dln2, GFP_KERNEL);
782 	if (ret)
783 		goto out_stop_rx;
784 
785 	ret = dln2_hw_init(dln2);
786 	if (ret < 0) {
787 		dev_err(dev, "failed to initialize hardware\n");
788 		goto out_stop_rx;
789 	}
790 
791 	ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs));
792 	if (ret != 0) {
793 		dev_err(dev, "failed to add mfd devices to core\n");
794 		goto out_stop_rx;
795 	}
796 
797 	return 0;
798 
799 out_stop_rx:
800 	dln2_stop_rx_urbs(dln2);
801 
802 out_free:
803 	dln2_free(dln2);
804 
805 	return ret;
806 }
807 
dln2_suspend(struct usb_interface * iface,pm_message_t message)808 static int dln2_suspend(struct usb_interface *iface, pm_message_t message)
809 {
810 	struct dln2_dev *dln2 = usb_get_intfdata(iface);
811 
812 	dln2_stop(dln2);
813 
814 	return 0;
815 }
816 
dln2_resume(struct usb_interface * iface)817 static int dln2_resume(struct usb_interface *iface)
818 {
819 	struct dln2_dev *dln2 = usb_get_intfdata(iface);
820 
821 	dln2->disconnect = false;
822 
823 	return dln2_start_rx_urbs(dln2, GFP_NOIO);
824 }
825 
826 static const struct usb_device_id dln2_table[] = {
827 	{ USB_DEVICE(0xa257, 0x2013) },
828 	{ }
829 };
830 
831 MODULE_DEVICE_TABLE(usb, dln2_table);
832 
833 static struct usb_driver dln2_driver = {
834 	.name = "dln2",
835 	.probe = dln2_probe,
836 	.disconnect = dln2_disconnect,
837 	.id_table = dln2_table,
838 	.suspend = dln2_suspend,
839 	.resume = dln2_resume,
840 };
841 
842 module_usb_driver(dln2_driver);
843 
844 MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
845 MODULE_DESCRIPTION("Core driver for the Diolan DLN2 interface adapter");
846 MODULE_LICENSE("GPL v2");
847