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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 	bool valid_slot = false;
203 
204 	if (rx_slot >= DLN2_MAX_RX_SLOTS)
205 		goto out;
206 
207 	rxc = &rxs->slots[rx_slot];
208 
209 	/*
210 	 * No need to disable interrupts as this lock is not taken in interrupt
211 	 * context elsewhere in this driver. This function (or its callers) are
212 	 * also not exported to other modules.
213 	 */
214 	spin_lock(&rxs->lock);
215 	if (rxc->in_use && !rxc->urb) {
216 		rxc->urb = urb;
217 		complete(&rxc->done);
218 		valid_slot = true;
219 	}
220 	spin_unlock(&rxs->lock);
221 
222 out:
223 	if (!valid_slot)
224 		dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);
225 
226 	return valid_slot;
227 }
228 
dln2_run_event_callbacks(struct dln2_dev * dln2,u16 id,u16 echo,void * data,int len)229 static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
230 				     void *data, int len)
231 {
232 	struct dln2_event_cb_entry *i;
233 
234 	rcu_read_lock();
235 
236 	list_for_each_entry_rcu(i, &dln2->event_cb_list, list) {
237 		if (i->id == id) {
238 			i->callback(i->pdev, echo, data, len);
239 			break;
240 		}
241 	}
242 
243 	rcu_read_unlock();
244 }
245 
dln2_rx(struct urb * urb)246 static void dln2_rx(struct urb *urb)
247 {
248 	struct dln2_dev *dln2 = urb->context;
249 	struct dln2_header *hdr = urb->transfer_buffer;
250 	struct device *dev = &dln2->interface->dev;
251 	u16 id, echo, handle, size;
252 	u8 *data;
253 	int len;
254 	int err;
255 
256 	switch (urb->status) {
257 	case 0:
258 		/* success */
259 		break;
260 	case -ECONNRESET:
261 	case -ENOENT:
262 	case -ESHUTDOWN:
263 	case -EPIPE:
264 		/* this urb is terminated, clean up */
265 		dev_dbg(dev, "urb shutting down with status %d\n", urb->status);
266 		return;
267 	default:
268 		dev_dbg(dev, "nonzero urb status received %d\n", urb->status);
269 		goto out;
270 	}
271 
272 	if (urb->actual_length < sizeof(struct dln2_header)) {
273 		dev_err(dev, "short response: %d\n", urb->actual_length);
274 		goto out;
275 	}
276 
277 	handle = le16_to_cpu(hdr->handle);
278 	id = le16_to_cpu(hdr->id);
279 	echo = le16_to_cpu(hdr->echo);
280 	size = le16_to_cpu(hdr->size);
281 
282 	if (size != urb->actual_length) {
283 		dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n",
284 			handle, id, echo, size, urb->actual_length);
285 		goto out;
286 	}
287 
288 	if (handle >= DLN2_HANDLES) {
289 		dev_warn(dev, "invalid handle %d\n", handle);
290 		goto out;
291 	}
292 
293 	data = urb->transfer_buffer + sizeof(struct dln2_header);
294 	len = urb->actual_length - sizeof(struct dln2_header);
295 
296 	if (handle == DLN2_HANDLE_EVENT) {
297 		unsigned long flags;
298 
299 		spin_lock_irqsave(&dln2->event_cb_lock, flags);
300 		dln2_run_event_callbacks(dln2, id, echo, data, len);
301 		spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
302 	} else {
303 		/* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
304 		if (dln2_transfer_complete(dln2, urb, handle, echo))
305 			return;
306 	}
307 
308 out:
309 	err = usb_submit_urb(urb, GFP_ATOMIC);
310 	if (err < 0)
311 		dev_err(dev, "failed to resubmit RX URB: %d\n", err);
312 }
313 
dln2_prep_buf(u16 handle,u16 cmd,u16 echo,const void * obuf,int * obuf_len,gfp_t gfp)314 static void *dln2_prep_buf(u16 handle, u16 cmd, u16 echo, const void *obuf,
315 			   int *obuf_len, gfp_t gfp)
316 {
317 	int len;
318 	void *buf;
319 	struct dln2_header *hdr;
320 
321 	len = *obuf_len + sizeof(*hdr);
322 	buf = kmalloc(len, gfp);
323 	if (!buf)
324 		return NULL;
325 
326 	hdr = (struct dln2_header *)buf;
327 	hdr->id = cpu_to_le16(cmd);
328 	hdr->size = cpu_to_le16(len);
329 	hdr->echo = cpu_to_le16(echo);
330 	hdr->handle = cpu_to_le16(handle);
331 
332 	memcpy(buf + sizeof(*hdr), obuf, *obuf_len);
333 
334 	*obuf_len = len;
335 
336 	return buf;
337 }
338 
dln2_send_wait(struct dln2_dev * dln2,u16 handle,u16 cmd,u16 echo,const void * obuf,int obuf_len)339 static int dln2_send_wait(struct dln2_dev *dln2, u16 handle, u16 cmd, u16 echo,
340 			  const void *obuf, int obuf_len)
341 {
342 	int ret = 0;
343 	int len = obuf_len;
344 	void *buf;
345 	int actual;
346 
347 	buf = dln2_prep_buf(handle, cmd, echo, obuf, &len, GFP_KERNEL);
348 	if (!buf)
349 		return -ENOMEM;
350 
351 	ret = usb_bulk_msg(dln2->usb_dev,
352 			   usb_sndbulkpipe(dln2->usb_dev, dln2->ep_out),
353 			   buf, len, &actual, DLN2_USB_TIMEOUT);
354 
355 	kfree(buf);
356 
357 	return ret;
358 }
359 
find_free_slot(struct dln2_dev * dln2,u16 handle,int * slot)360 static bool find_free_slot(struct dln2_dev *dln2, u16 handle, int *slot)
361 {
362 	struct dln2_mod_rx_slots *rxs;
363 	unsigned long flags;
364 
365 	if (dln2->disconnect) {
366 		*slot = -ENODEV;
367 		return true;
368 	}
369 
370 	rxs = &dln2->mod_rx_slots[handle];
371 
372 	spin_lock_irqsave(&rxs->lock, flags);
373 
374 	*slot = find_first_zero_bit(rxs->bmap, DLN2_MAX_RX_SLOTS);
375 
376 	if (*slot < DLN2_MAX_RX_SLOTS) {
377 		struct dln2_rx_context *rxc = &rxs->slots[*slot];
378 
379 		set_bit(*slot, rxs->bmap);
380 		rxc->in_use = true;
381 	}
382 
383 	spin_unlock_irqrestore(&rxs->lock, flags);
384 
385 	return *slot < DLN2_MAX_RX_SLOTS;
386 }
387 
alloc_rx_slot(struct dln2_dev * dln2,u16 handle)388 static int alloc_rx_slot(struct dln2_dev *dln2, u16 handle)
389 {
390 	int ret;
391 	int slot;
392 
393 	/*
394 	 * No need to timeout here, the wait is bounded by the timeout in
395 	 * _dln2_transfer.
396 	 */
397 	ret = wait_event_interruptible(dln2->mod_rx_slots[handle].wq,
398 				       find_free_slot(dln2, handle, &slot));
399 	if (ret < 0)
400 		return ret;
401 
402 	return slot;
403 }
404 
free_rx_slot(struct dln2_dev * dln2,u16 handle,int slot)405 static void free_rx_slot(struct dln2_dev *dln2, u16 handle, int slot)
406 {
407 	struct dln2_mod_rx_slots *rxs;
408 	struct urb *urb = NULL;
409 	unsigned long flags;
410 	struct dln2_rx_context *rxc;
411 
412 	rxs = &dln2->mod_rx_slots[handle];
413 
414 	spin_lock_irqsave(&rxs->lock, flags);
415 
416 	clear_bit(slot, rxs->bmap);
417 
418 	rxc = &rxs->slots[slot];
419 	rxc->in_use = false;
420 	urb = rxc->urb;
421 	rxc->urb = NULL;
422 	reinit_completion(&rxc->done);
423 
424 	spin_unlock_irqrestore(&rxs->lock, flags);
425 
426 	if (urb) {
427 		int err;
428 		struct device *dev = &dln2->interface->dev;
429 
430 		err = usb_submit_urb(urb, GFP_KERNEL);
431 		if (err < 0)
432 			dev_err(dev, "failed to resubmit RX URB: %d\n", err);
433 	}
434 
435 	wake_up_interruptible(&rxs->wq);
436 }
437 
_dln2_transfer(struct dln2_dev * dln2,u16 handle,u16 cmd,const void * obuf,unsigned obuf_len,void * ibuf,unsigned * ibuf_len)438 static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
439 			  const void *obuf, unsigned obuf_len,
440 			  void *ibuf, unsigned *ibuf_len)
441 {
442 	int ret = 0;
443 	int rx_slot;
444 	struct dln2_response *rsp;
445 	struct dln2_rx_context *rxc;
446 	struct device *dev = &dln2->interface->dev;
447 	const unsigned long timeout = msecs_to_jiffies(DLN2_USB_TIMEOUT);
448 	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
449 	int size;
450 
451 	spin_lock(&dln2->disconnect_lock);
452 	if (!dln2->disconnect)
453 		dln2->active_transfers++;
454 	else
455 		ret = -ENODEV;
456 	spin_unlock(&dln2->disconnect_lock);
457 
458 	if (ret)
459 		return ret;
460 
461 	rx_slot = alloc_rx_slot(dln2, handle);
462 	if (rx_slot < 0) {
463 		ret = rx_slot;
464 		goto out_decr;
465 	}
466 
467 	ret = dln2_send_wait(dln2, handle, cmd, rx_slot, obuf, obuf_len);
468 	if (ret < 0) {
469 		dev_err(dev, "USB write failed: %d\n", ret);
470 		goto out_free_rx_slot;
471 	}
472 
473 	rxc = &rxs->slots[rx_slot];
474 
475 	ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
476 	if (ret <= 0) {
477 		if (!ret)
478 			ret = -ETIMEDOUT;
479 		goto out_free_rx_slot;
480 	} else {
481 		ret = 0;
482 	}
483 
484 	if (dln2->disconnect) {
485 		ret = -ENODEV;
486 		goto out_free_rx_slot;
487 	}
488 
489 	/* if we got here we know that the response header has been checked */
490 	rsp = rxc->urb->transfer_buffer;
491 	size = le16_to_cpu(rsp->hdr.size);
492 
493 	if (size < sizeof(*rsp)) {
494 		ret = -EPROTO;
495 		goto out_free_rx_slot;
496 	}
497 
498 	if (le16_to_cpu(rsp->result) > 0x80) {
499 		dev_dbg(dev, "%d received response with error %d\n",
500 			handle, le16_to_cpu(rsp->result));
501 		ret = -EREMOTEIO;
502 		goto out_free_rx_slot;
503 	}
504 
505 	if (!ibuf)
506 		goto out_free_rx_slot;
507 
508 	if (*ibuf_len > size - sizeof(*rsp))
509 		*ibuf_len = size - sizeof(*rsp);
510 
511 	memcpy(ibuf, rsp + 1, *ibuf_len);
512 
513 out_free_rx_slot:
514 	free_rx_slot(dln2, handle, rx_slot);
515 out_decr:
516 	spin_lock(&dln2->disconnect_lock);
517 	dln2->active_transfers--;
518 	spin_unlock(&dln2->disconnect_lock);
519 	if (dln2->disconnect)
520 		wake_up(&dln2->disconnect_wq);
521 
522 	return ret;
523 }
524 
dln2_transfer(struct platform_device * pdev,u16 cmd,const void * obuf,unsigned obuf_len,void * ibuf,unsigned * ibuf_len)525 int dln2_transfer(struct platform_device *pdev, u16 cmd,
526 		  const void *obuf, unsigned obuf_len,
527 		  void *ibuf, unsigned *ibuf_len)
528 {
529 	struct dln2_platform_data *dln2_pdata;
530 	struct dln2_dev *dln2;
531 	u16 handle;
532 
533 	dln2 = dev_get_drvdata(pdev->dev.parent);
534 	dln2_pdata = dev_get_platdata(&pdev->dev);
535 	handle = dln2_pdata->handle;
536 
537 	return _dln2_transfer(dln2, handle, cmd, obuf, obuf_len, ibuf,
538 			      ibuf_len);
539 }
540 EXPORT_SYMBOL(dln2_transfer);
541 
dln2_check_hw(struct dln2_dev * dln2)542 static int dln2_check_hw(struct dln2_dev *dln2)
543 {
544 	int ret;
545 	__le32 hw_type;
546 	int len = sizeof(hw_type);
547 
548 	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_VER,
549 			     NULL, 0, &hw_type, &len);
550 	if (ret < 0)
551 		return ret;
552 	if (len < sizeof(hw_type))
553 		return -EREMOTEIO;
554 
555 	if (le32_to_cpu(hw_type) != DLN2_HW_ID) {
556 		dev_err(&dln2->interface->dev, "Device ID 0x%x not supported\n",
557 			le32_to_cpu(hw_type));
558 		return -ENODEV;
559 	}
560 
561 	return 0;
562 }
563 
dln2_print_serialno(struct dln2_dev * dln2)564 static int dln2_print_serialno(struct dln2_dev *dln2)
565 {
566 	int ret;
567 	__le32 serial_no;
568 	int len = sizeof(serial_no);
569 	struct device *dev = &dln2->interface->dev;
570 
571 	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
572 			     &serial_no, &len);
573 	if (ret < 0)
574 		return ret;
575 	if (len < sizeof(serial_no))
576 		return -EREMOTEIO;
577 
578 	dev_info(dev, "Diolan DLN2 serial %u\n", le32_to_cpu(serial_no));
579 
580 	return 0;
581 }
582 
dln2_hw_init(struct dln2_dev * dln2)583 static int dln2_hw_init(struct dln2_dev *dln2)
584 {
585 	int ret;
586 
587 	ret = dln2_check_hw(dln2);
588 	if (ret < 0)
589 		return ret;
590 
591 	return dln2_print_serialno(dln2);
592 }
593 
dln2_free_rx_urbs(struct dln2_dev * dln2)594 static void dln2_free_rx_urbs(struct dln2_dev *dln2)
595 {
596 	int i;
597 
598 	for (i = 0; i < DLN2_MAX_URBS; i++) {
599 		usb_free_urb(dln2->rx_urb[i]);
600 		kfree(dln2->rx_buf[i]);
601 	}
602 }
603 
dln2_stop_rx_urbs(struct dln2_dev * dln2)604 static void dln2_stop_rx_urbs(struct dln2_dev *dln2)
605 {
606 	int i;
607 
608 	for (i = 0; i < DLN2_MAX_URBS; i++)
609 		usb_kill_urb(dln2->rx_urb[i]);
610 }
611 
dln2_free(struct dln2_dev * dln2)612 static void dln2_free(struct dln2_dev *dln2)
613 {
614 	dln2_free_rx_urbs(dln2);
615 	usb_put_dev(dln2->usb_dev);
616 	kfree(dln2);
617 }
618 
dln2_setup_rx_urbs(struct dln2_dev * dln2,struct usb_host_interface * hostif)619 static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
620 			      struct usb_host_interface *hostif)
621 {
622 	int i;
623 	const int rx_max_size = DLN2_RX_BUF_SIZE;
624 
625 	for (i = 0; i < DLN2_MAX_URBS; i++) {
626 		dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
627 		if (!dln2->rx_buf[i])
628 			return -ENOMEM;
629 
630 		dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
631 		if (!dln2->rx_urb[i])
632 			return -ENOMEM;
633 
634 		usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev,
635 				  usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in),
636 				  dln2->rx_buf[i], rx_max_size, dln2_rx, dln2);
637 	}
638 
639 	return 0;
640 }
641 
dln2_start_rx_urbs(struct dln2_dev * dln2,gfp_t gfp)642 static int dln2_start_rx_urbs(struct dln2_dev *dln2, gfp_t gfp)
643 {
644 	struct device *dev = &dln2->interface->dev;
645 	int ret;
646 	int i;
647 
648 	for (i = 0; i < DLN2_MAX_URBS; i++) {
649 		ret = usb_submit_urb(dln2->rx_urb[i], gfp);
650 		if (ret < 0) {
651 			dev_err(dev, "failed to submit RX URB: %d\n", ret);
652 			return ret;
653 		}
654 	}
655 
656 	return 0;
657 }
658 
659 static struct dln2_platform_data dln2_pdata_gpio = {
660 	.handle = DLN2_HANDLE_GPIO,
661 };
662 
663 /* Only one I2C port seems to be supported on current hardware */
664 static struct dln2_platform_data dln2_pdata_i2c = {
665 	.handle = DLN2_HANDLE_I2C,
666 	.port = 0,
667 };
668 
669 /* Only one SPI port supported */
670 static struct dln2_platform_data dln2_pdata_spi = {
671 	.handle = DLN2_HANDLE_SPI,
672 	.port = 0,
673 };
674 
675 static const struct mfd_cell dln2_devs[] = {
676 	{
677 		.name = "dln2-gpio",
678 		.platform_data = &dln2_pdata_gpio,
679 		.pdata_size = sizeof(struct dln2_platform_data),
680 	},
681 	{
682 		.name = "dln2-i2c",
683 		.platform_data = &dln2_pdata_i2c,
684 		.pdata_size = sizeof(struct dln2_platform_data),
685 	},
686 	{
687 		.name = "dln2-spi",
688 		.platform_data = &dln2_pdata_spi,
689 		.pdata_size = sizeof(struct dln2_platform_data),
690 	},
691 };
692 
dln2_stop(struct dln2_dev * dln2)693 static void dln2_stop(struct dln2_dev *dln2)
694 {
695 	int i, j;
696 
697 	/* don't allow starting new transfers */
698 	spin_lock(&dln2->disconnect_lock);
699 	dln2->disconnect = true;
700 	spin_unlock(&dln2->disconnect_lock);
701 
702 	/* cancel in progress transfers */
703 	for (i = 0; i < DLN2_HANDLES; i++) {
704 		struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[i];
705 		unsigned long flags;
706 
707 		spin_lock_irqsave(&rxs->lock, flags);
708 
709 		/* cancel all response waiters */
710 		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) {
711 			struct dln2_rx_context *rxc = &rxs->slots[j];
712 
713 			if (rxc->in_use)
714 				complete(&rxc->done);
715 		}
716 
717 		spin_unlock_irqrestore(&rxs->lock, flags);
718 	}
719 
720 	/* wait for transfers to end */
721 	wait_event(dln2->disconnect_wq, !dln2->active_transfers);
722 
723 	dln2_stop_rx_urbs(dln2);
724 }
725 
dln2_disconnect(struct usb_interface * interface)726 static void dln2_disconnect(struct usb_interface *interface)
727 {
728 	struct dln2_dev *dln2 = usb_get_intfdata(interface);
729 
730 	dln2_stop(dln2);
731 
732 	mfd_remove_devices(&interface->dev);
733 
734 	dln2_free(dln2);
735 }
736 
dln2_probe(struct usb_interface * interface,const struct usb_device_id * usb_id)737 static int dln2_probe(struct usb_interface *interface,
738 		      const struct usb_device_id *usb_id)
739 {
740 	struct usb_host_interface *hostif = interface->cur_altsetting;
741 	struct usb_endpoint_descriptor *epin;
742 	struct usb_endpoint_descriptor *epout;
743 	struct device *dev = &interface->dev;
744 	struct dln2_dev *dln2;
745 	int ret;
746 	int i, j;
747 
748 	if (hostif->desc.bInterfaceNumber != 0 ||
749 	    hostif->desc.bNumEndpoints < 2)
750 		return -ENODEV;
751 
752 	epout = &hostif->endpoint[DLN2_EP_OUT].desc;
753 	if (!usb_endpoint_is_bulk_out(epout))
754 		return -ENODEV;
755 	epin = &hostif->endpoint[DLN2_EP_IN].desc;
756 	if (!usb_endpoint_is_bulk_in(epin))
757 		return -ENODEV;
758 
759 	dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
760 	if (!dln2)
761 		return -ENOMEM;
762 
763 	dln2->ep_out = epout->bEndpointAddress;
764 	dln2->ep_in = epin->bEndpointAddress;
765 	dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
766 	dln2->interface = interface;
767 	usb_set_intfdata(interface, dln2);
768 	init_waitqueue_head(&dln2->disconnect_wq);
769 
770 	for (i = 0; i < DLN2_HANDLES; i++) {
771 		init_waitqueue_head(&dln2->mod_rx_slots[i].wq);
772 		spin_lock_init(&dln2->mod_rx_slots[i].lock);
773 		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++)
774 			init_completion(&dln2->mod_rx_slots[i].slots[j].done);
775 	}
776 
777 	spin_lock_init(&dln2->event_cb_lock);
778 	spin_lock_init(&dln2->disconnect_lock);
779 	INIT_LIST_HEAD(&dln2->event_cb_list);
780 
781 	ret = dln2_setup_rx_urbs(dln2, hostif);
782 	if (ret)
783 		goto out_free;
784 
785 	ret = dln2_start_rx_urbs(dln2, GFP_KERNEL);
786 	if (ret)
787 		goto out_stop_rx;
788 
789 	ret = dln2_hw_init(dln2);
790 	if (ret < 0) {
791 		dev_err(dev, "failed to initialize hardware\n");
792 		goto out_stop_rx;
793 	}
794 
795 	ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs));
796 	if (ret != 0) {
797 		dev_err(dev, "failed to add mfd devices to core\n");
798 		goto out_stop_rx;
799 	}
800 
801 	return 0;
802 
803 out_stop_rx:
804 	dln2_stop_rx_urbs(dln2);
805 
806 out_free:
807 	dln2_free(dln2);
808 
809 	return ret;
810 }
811 
dln2_suspend(struct usb_interface * iface,pm_message_t message)812 static int dln2_suspend(struct usb_interface *iface, pm_message_t message)
813 {
814 	struct dln2_dev *dln2 = usb_get_intfdata(iface);
815 
816 	dln2_stop(dln2);
817 
818 	return 0;
819 }
820 
dln2_resume(struct usb_interface * iface)821 static int dln2_resume(struct usb_interface *iface)
822 {
823 	struct dln2_dev *dln2 = usb_get_intfdata(iface);
824 
825 	dln2->disconnect = false;
826 
827 	return dln2_start_rx_urbs(dln2, GFP_NOIO);
828 }
829 
830 static const struct usb_device_id dln2_table[] = {
831 	{ USB_DEVICE(0xa257, 0x2013) },
832 	{ }
833 };
834 
835 MODULE_DEVICE_TABLE(usb, dln2_table);
836 
837 static struct usb_driver dln2_driver = {
838 	.name = "dln2",
839 	.probe = dln2_probe,
840 	.disconnect = dln2_disconnect,
841 	.id_table = dln2_table,
842 	.suspend = dln2_suspend,
843 	.resume = dln2_resume,
844 };
845 
846 module_usb_driver(dln2_driver);
847 
848 MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
849 MODULE_DESCRIPTION("Core driver for the Diolan DLN2 interface adapter");
850 MODULE_LICENSE("GPL v2");
851