1/*
2 * Surface2.0/SUR40/PixelSense input driver
3 *
4 * Copyright (c) 2014 by Florian 'floe' Echtler <floe@butterbrot.org>
5 *
6 * Derived from the USB Skeleton driver 1.1,
7 * Copyright (c) 2003 Greg Kroah-Hartman (greg@kroah.com)
8 *
9 * and from the Apple USB BCM5974 multitouch driver,
10 * Copyright (c) 2008 Henrik Rydberg (rydberg@euromail.se)
11 *
12 * and from the generic hid-multitouch driver,
13 * Copyright (c) 2010-2012 Stephane Chatty <chatty@enac.fr>
14 *
15 * and from the v4l2-pci-skeleton driver,
16 * Copyright (c) Copyright 2014 Cisco Systems, Inc.
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License as
20 * published by the Free Software Foundation; either version 2 of
21 * the License, or (at your option) any later version.
22 */
23
24#include <linux/kernel.h>
25#include <linux/errno.h>
26#include <linux/delay.h>
27#include <linux/init.h>
28#include <linux/slab.h>
29#include <linux/module.h>
30#include <linux/completion.h>
31#include <linux/uaccess.h>
32#include <linux/usb.h>
33#include <linux/printk.h>
34#include <linux/input-polldev.h>
35#include <linux/input/mt.h>
36#include <linux/usb/input.h>
37#include <linux/videodev2.h>
38#include <media/v4l2-device.h>
39#include <media/v4l2-dev.h>
40#include <media/v4l2-ioctl.h>
41#include <media/videobuf2-dma-sg.h>
42
43/* read 512 bytes from endpoint 0x86 -> get header + blobs */
44struct sur40_header {
45
46	__le16 type;       /* always 0x0001 */
47	__le16 count;      /* count of blobs (if 0: continue prev. packet) */
48
49	__le32 packet_id;  /* unique ID for all packets in one frame */
50
51	__le32 timestamp;  /* milliseconds (inc. by 16 or 17 each frame) */
52	__le32 unknown;    /* "epoch?" always 02/03 00 00 00 */
53
54} __packed;
55
56struct sur40_blob {
57
58	__le16 blob_id;
59
60	u8 action;         /* 0x02 = enter/exit, 0x03 = update (?) */
61	u8 unknown;        /* always 0x01 or 0x02 (no idea what this is?) */
62
63	__le16 bb_pos_x;   /* upper left corner of bounding box */
64	__le16 bb_pos_y;
65
66	__le16 bb_size_x;  /* size of bounding box */
67	__le16 bb_size_y;
68
69	__le16 pos_x;      /* finger tip position */
70	__le16 pos_y;
71
72	__le16 ctr_x;      /* centroid position */
73	__le16 ctr_y;
74
75	__le16 axis_x;     /* somehow related to major/minor axis, mostly: */
76	__le16 axis_y;     /* axis_x == bb_size_y && axis_y == bb_size_x */
77
78	__le32 angle;      /* orientation in radians relative to x axis -
79	                      actually an IEEE754 float, don't use in kernel */
80
81	__le32 area;       /* size in pixels/pressure (?) */
82
83	u8 padding[32];
84
85} __packed;
86
87/* combined header/blob data */
88struct sur40_data {
89	struct sur40_header header;
90	struct sur40_blob   blobs[];
91} __packed;
92
93/* read 512 bytes from endpoint 0x82 -> get header below
94 * continue reading 16k blocks until header.size bytes read */
95struct sur40_image_header {
96	__le32 magic;     /* "SUBF" */
97	__le32 packet_id;
98	__le32 size;      /* always 0x0007e900 = 960x540 */
99	__le32 timestamp; /* milliseconds (increases by 16 or 17 each frame) */
100	__le32 unknown;   /* "epoch?" always 02/03 00 00 00 */
101} __packed;
102
103/* version information */
104#define DRIVER_SHORT   "sur40"
105#define DRIVER_LONG    "Samsung SUR40"
106#define DRIVER_AUTHOR  "Florian 'floe' Echtler <floe@butterbrot.org>"
107#define DRIVER_DESC    "Surface2.0/SUR40/PixelSense input driver"
108
109/* vendor and device IDs */
110#define ID_MICROSOFT 0x045e
111#define ID_SUR40     0x0775
112
113/* sensor resolution */
114#define SENSOR_RES_X 1920
115#define SENSOR_RES_Y 1080
116
117/* touch data endpoint */
118#define TOUCH_ENDPOINT 0x86
119
120/* video data endpoint */
121#define VIDEO_ENDPOINT 0x82
122
123/* video header fields */
124#define VIDEO_HEADER_MAGIC 0x46425553
125#define VIDEO_PACKET_SIZE  16384
126
127/* polling interval (ms) */
128#define POLL_INTERVAL 10
129
130/* maximum number of contacts FIXME: this is a guess? */
131#define MAX_CONTACTS 64
132
133/* control commands */
134#define SUR40_GET_VERSION 0xb0 /* 12 bytes string    */
135#define SUR40_UNKNOWN1    0xb3 /*  5 bytes           */
136#define SUR40_UNKNOWN2    0xc1 /* 24 bytes           */
137
138#define SUR40_GET_STATE   0xc5 /*  4 bytes state (?) */
139#define SUR40_GET_SENSORS 0xb1 /*  8 bytes sensors   */
140
141/* master device state */
142struct sur40_state {
143
144	struct usb_device *usbdev;
145	struct device *dev;
146	struct input_polled_dev *input;
147
148	struct v4l2_device v4l2;
149	struct video_device vdev;
150	struct mutex lock;
151
152	struct vb2_queue queue;
153	struct vb2_alloc_ctx *alloc_ctx;
154	struct list_head buf_list;
155	spinlock_t qlock;
156	int sequence;
157
158	struct sur40_data *bulk_in_buffer;
159	size_t bulk_in_size;
160	u8 bulk_in_epaddr;
161
162	char phys[64];
163};
164
165struct sur40_buffer {
166	struct vb2_buffer vb;
167	struct list_head list;
168};
169
170/* forward declarations */
171static const struct video_device sur40_video_device;
172static const struct v4l2_pix_format sur40_video_format;
173static const struct vb2_queue sur40_queue;
174static void sur40_process_video(struct sur40_state *sur40);
175
176/*
177 * Note: an earlier, non-public version of this driver used USB_RECIP_ENDPOINT
178 * here by mistake which is very likely to have corrupted the firmware EEPROM
179 * on two separate SUR40 devices. Thanks to Alan Stern who spotted this bug.
180 * Should you ever run into a similar problem, the background story to this
181 * incident and instructions on how to fix the corrupted EEPROM are available
182 * at https://floe.butterbrot.org/matrix/hacking/surface/brick.html
183*/
184
185/* command wrapper */
186static int sur40_command(struct sur40_state *dev,
187			 u8 command, u16 index, void *buffer, u16 size)
188{
189	return usb_control_msg(dev->usbdev, usb_rcvctrlpipe(dev->usbdev, 0),
190			       command,
191			       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
192			       0x00, index, buffer, size, 1000);
193}
194
195/* Initialization routine, called from sur40_open */
196static int sur40_init(struct sur40_state *dev)
197{
198	int result;
199	u8 buffer[24];
200
201	/* stupidly replay the original MS driver init sequence */
202	result = sur40_command(dev, SUR40_GET_VERSION, 0x00, buffer, 12);
203	if (result < 0)
204		return result;
205
206	result = sur40_command(dev, SUR40_GET_VERSION, 0x01, buffer, 12);
207	if (result < 0)
208		return result;
209
210	result = sur40_command(dev, SUR40_GET_VERSION, 0x02, buffer, 12);
211	if (result < 0)
212		return result;
213
214	result = sur40_command(dev, SUR40_UNKNOWN2,    0x00, buffer, 24);
215	if (result < 0)
216		return result;
217
218	result = sur40_command(dev, SUR40_UNKNOWN1,    0x00, buffer,  5);
219	if (result < 0)
220		return result;
221
222	result = sur40_command(dev, SUR40_GET_VERSION, 0x03, buffer, 12);
223
224	/*
225	 * Discard the result buffer - no known data inside except
226	 * some version strings, maybe extract these sometime...
227	 */
228
229	return result;
230}
231
232/*
233 * Callback routines from input_polled_dev
234 */
235
236/* Enable the device, polling will now start. */
237static void sur40_open(struct input_polled_dev *polldev)
238{
239	struct sur40_state *sur40 = polldev->private;
240
241	dev_dbg(sur40->dev, "open\n");
242	sur40_init(sur40);
243}
244
245/* Disable device, polling has stopped. */
246static void sur40_close(struct input_polled_dev *polldev)
247{
248	struct sur40_state *sur40 = polldev->private;
249
250	dev_dbg(sur40->dev, "close\n");
251	/*
252	 * There is no known way to stop the device, so we simply
253	 * stop polling.
254	 */
255}
256
257/*
258 * This function is called when a whole contact has been processed,
259 * so that it can assign it to a slot and store the data there.
260 */
261static void sur40_report_blob(struct sur40_blob *blob, struct input_dev *input)
262{
263	int wide, major, minor;
264
265	int bb_size_x = le16_to_cpu(blob->bb_size_x);
266	int bb_size_y = le16_to_cpu(blob->bb_size_y);
267
268	int pos_x = le16_to_cpu(blob->pos_x);
269	int pos_y = le16_to_cpu(blob->pos_y);
270
271	int ctr_x = le16_to_cpu(blob->ctr_x);
272	int ctr_y = le16_to_cpu(blob->ctr_y);
273
274	int slotnum = input_mt_get_slot_by_key(input, blob->blob_id);
275	if (slotnum < 0 || slotnum >= MAX_CONTACTS)
276		return;
277
278	input_mt_slot(input, slotnum);
279	input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
280	wide = (bb_size_x > bb_size_y);
281	major = max(bb_size_x, bb_size_y);
282	minor = min(bb_size_x, bb_size_y);
283
284	input_report_abs(input, ABS_MT_POSITION_X, pos_x);
285	input_report_abs(input, ABS_MT_POSITION_Y, pos_y);
286	input_report_abs(input, ABS_MT_TOOL_X, ctr_x);
287	input_report_abs(input, ABS_MT_TOOL_Y, ctr_y);
288
289	/* TODO: use a better orientation measure */
290	input_report_abs(input, ABS_MT_ORIENTATION, wide);
291	input_report_abs(input, ABS_MT_TOUCH_MAJOR, major);
292	input_report_abs(input, ABS_MT_TOUCH_MINOR, minor);
293}
294
295/* core function: poll for new input data */
296static void sur40_poll(struct input_polled_dev *polldev)
297{
298	struct sur40_state *sur40 = polldev->private;
299	struct input_dev *input = polldev->input;
300	int result, bulk_read, need_blobs, packet_blobs, i;
301	u32 uninitialized_var(packet_id);
302
303	struct sur40_header *header = &sur40->bulk_in_buffer->header;
304	struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0];
305
306	dev_dbg(sur40->dev, "poll\n");
307
308	need_blobs = -1;
309
310	do {
311
312		/* perform a blocking bulk read to get data from the device */
313		result = usb_bulk_msg(sur40->usbdev,
314			usb_rcvbulkpipe(sur40->usbdev, sur40->bulk_in_epaddr),
315			sur40->bulk_in_buffer, sur40->bulk_in_size,
316			&bulk_read, 1000);
317
318		dev_dbg(sur40->dev, "received %d bytes\n", bulk_read);
319
320		if (result < 0) {
321			dev_err(sur40->dev, "error in usb_bulk_read\n");
322			return;
323		}
324
325		result = bulk_read - sizeof(struct sur40_header);
326
327		if (result % sizeof(struct sur40_blob) != 0) {
328			dev_err(sur40->dev, "transfer size mismatch\n");
329			return;
330		}
331
332		/* first packet? */
333		if (need_blobs == -1) {
334			need_blobs = le16_to_cpu(header->count);
335			dev_dbg(sur40->dev, "need %d blobs\n", need_blobs);
336			packet_id = le32_to_cpu(header->packet_id);
337		}
338
339		/*
340		 * Sanity check. when video data is also being retrieved, the
341		 * packet ID will usually increase in the middle of a series
342		 * instead of at the end.
343		 */
344		if (packet_id != header->packet_id)
345			dev_warn(sur40->dev, "packet ID mismatch\n");
346
347		packet_blobs = result / sizeof(struct sur40_blob);
348		dev_dbg(sur40->dev, "received %d blobs\n", packet_blobs);
349
350		/* packets always contain at least 4 blobs, even if empty */
351		if (packet_blobs > need_blobs)
352			packet_blobs = need_blobs;
353
354		for (i = 0; i < packet_blobs; i++) {
355			need_blobs--;
356			dev_dbg(sur40->dev, "processing blob\n");
357			sur40_report_blob(&(inblob[i]), input);
358		}
359
360	} while (need_blobs > 0);
361
362	input_mt_sync_frame(input);
363	input_sync(input);
364
365	sur40_process_video(sur40);
366}
367
368/* deal with video data */
369static void sur40_process_video(struct sur40_state *sur40)
370{
371
372	struct sur40_image_header *img = (void *)(sur40->bulk_in_buffer);
373	struct sur40_buffer *new_buf;
374	struct usb_sg_request sgr;
375	struct sg_table *sgt;
376	int result, bulk_read;
377
378	if (!vb2_start_streaming_called(&sur40->queue))
379		return;
380
381	/* get a new buffer from the list */
382	spin_lock(&sur40->qlock);
383	if (list_empty(&sur40->buf_list)) {
384		dev_dbg(sur40->dev, "buffer queue empty\n");
385		spin_unlock(&sur40->qlock);
386		return;
387	}
388	new_buf = list_entry(sur40->buf_list.next, struct sur40_buffer, list);
389	list_del(&new_buf->list);
390	spin_unlock(&sur40->qlock);
391
392	/* retrieve data via bulk read */
393	result = usb_bulk_msg(sur40->usbdev,
394			usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT),
395			sur40->bulk_in_buffer, sur40->bulk_in_size,
396			&bulk_read, 1000);
397
398	if (result < 0) {
399		dev_err(sur40->dev, "error in usb_bulk_read\n");
400		goto err_poll;
401	}
402
403	if (bulk_read != sizeof(struct sur40_image_header)) {
404		dev_err(sur40->dev, "received %d bytes (%zd expected)\n",
405			bulk_read, sizeof(struct sur40_image_header));
406		goto err_poll;
407	}
408
409	if (le32_to_cpu(img->magic) != VIDEO_HEADER_MAGIC) {
410		dev_err(sur40->dev, "image magic mismatch\n");
411		goto err_poll;
412	}
413
414	if (le32_to_cpu(img->size) != sur40_video_format.sizeimage) {
415		dev_err(sur40->dev, "image size mismatch\n");
416		goto err_poll;
417	}
418
419	sgt = vb2_dma_sg_plane_desc(&new_buf->vb, 0);
420
421	result = usb_sg_init(&sgr, sur40->usbdev,
422		usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT), 0,
423		sgt->sgl, sgt->nents, sur40_video_format.sizeimage, 0);
424	if (result < 0) {
425		dev_err(sur40->dev, "error %d in usb_sg_init\n", result);
426		goto err_poll;
427	}
428
429	usb_sg_wait(&sgr);
430	if (sgr.status < 0) {
431		dev_err(sur40->dev, "error %d in usb_sg_wait\n", sgr.status);
432		goto err_poll;
433	}
434
435	/* mark as finished */
436	v4l2_get_timestamp(&new_buf->vb.v4l2_buf.timestamp);
437	new_buf->vb.v4l2_buf.sequence = sur40->sequence++;
438	new_buf->vb.v4l2_buf.field = V4L2_FIELD_NONE;
439	vb2_buffer_done(&new_buf->vb, VB2_BUF_STATE_DONE);
440	return;
441
442err_poll:
443	vb2_buffer_done(&new_buf->vb, VB2_BUF_STATE_ERROR);
444}
445
446/* Initialize input device parameters. */
447static void sur40_input_setup(struct input_dev *input_dev)
448{
449	__set_bit(EV_KEY, input_dev->evbit);
450	__set_bit(EV_ABS, input_dev->evbit);
451
452	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
453			     0, SENSOR_RES_X, 0, 0);
454	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
455			     0, SENSOR_RES_Y, 0, 0);
456
457	input_set_abs_params(input_dev, ABS_MT_TOOL_X,
458			     0, SENSOR_RES_X, 0, 0);
459	input_set_abs_params(input_dev, ABS_MT_TOOL_Y,
460			     0, SENSOR_RES_Y, 0, 0);
461
462	/* max value unknown, but major/minor axis
463	 * can never be larger than screen */
464	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
465			     0, SENSOR_RES_X, 0, 0);
466	input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
467			     0, SENSOR_RES_Y, 0, 0);
468
469	input_set_abs_params(input_dev, ABS_MT_ORIENTATION, 0, 1, 0, 0);
470
471	input_mt_init_slots(input_dev, MAX_CONTACTS,
472			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
473}
474
475/* Check candidate USB interface. */
476static int sur40_probe(struct usb_interface *interface,
477		       const struct usb_device_id *id)
478{
479	struct usb_device *usbdev = interface_to_usbdev(interface);
480	struct sur40_state *sur40;
481	struct usb_host_interface *iface_desc;
482	struct usb_endpoint_descriptor *endpoint;
483	struct input_polled_dev *poll_dev;
484	int error;
485
486	/* Check if we really have the right interface. */
487	iface_desc = &interface->altsetting[0];
488	if (iface_desc->desc.bInterfaceClass != 0xFF)
489		return -ENODEV;
490
491	/* Use endpoint #4 (0x86). */
492	endpoint = &iface_desc->endpoint[4].desc;
493	if (endpoint->bEndpointAddress != TOUCH_ENDPOINT)
494		return -ENODEV;
495
496	/* Allocate memory for our device state and initialize it. */
497	sur40 = kzalloc(sizeof(struct sur40_state), GFP_KERNEL);
498	if (!sur40)
499		return -ENOMEM;
500
501	poll_dev = input_allocate_polled_device();
502	if (!poll_dev) {
503		error = -ENOMEM;
504		goto err_free_dev;
505	}
506
507	/* initialize locks/lists */
508	INIT_LIST_HEAD(&sur40->buf_list);
509	spin_lock_init(&sur40->qlock);
510	mutex_init(&sur40->lock);
511
512	/* Set up polled input device control structure */
513	poll_dev->private = sur40;
514	poll_dev->poll_interval = POLL_INTERVAL;
515	poll_dev->open = sur40_open;
516	poll_dev->poll = sur40_poll;
517	poll_dev->close = sur40_close;
518
519	/* Set up regular input device structure */
520	sur40_input_setup(poll_dev->input);
521
522	poll_dev->input->name = DRIVER_LONG;
523	usb_to_input_id(usbdev, &poll_dev->input->id);
524	usb_make_path(usbdev, sur40->phys, sizeof(sur40->phys));
525	strlcat(sur40->phys, "/input0", sizeof(sur40->phys));
526	poll_dev->input->phys = sur40->phys;
527	poll_dev->input->dev.parent = &interface->dev;
528
529	sur40->usbdev = usbdev;
530	sur40->dev = &interface->dev;
531	sur40->input = poll_dev;
532
533	/* use the bulk-in endpoint tested above */
534	sur40->bulk_in_size = usb_endpoint_maxp(endpoint);
535	sur40->bulk_in_epaddr = endpoint->bEndpointAddress;
536	sur40->bulk_in_buffer = kmalloc(sur40->bulk_in_size, GFP_KERNEL);
537	if (!sur40->bulk_in_buffer) {
538		dev_err(&interface->dev, "Unable to allocate input buffer.");
539		error = -ENOMEM;
540		goto err_free_polldev;
541	}
542
543	/* register the polled input device */
544	error = input_register_polled_device(poll_dev);
545	if (error) {
546		dev_err(&interface->dev,
547			"Unable to register polled input device.");
548		goto err_free_buffer;
549	}
550
551	/* register the video master device */
552	snprintf(sur40->v4l2.name, sizeof(sur40->v4l2.name), "%s", DRIVER_LONG);
553	error = v4l2_device_register(sur40->dev, &sur40->v4l2);
554	if (error) {
555		dev_err(&interface->dev,
556			"Unable to register video master device.");
557		goto err_unreg_v4l2;
558	}
559
560	/* initialize the lock and subdevice */
561	sur40->queue = sur40_queue;
562	sur40->queue.drv_priv = sur40;
563	sur40->queue.lock = &sur40->lock;
564
565	/* initialize the queue */
566	error = vb2_queue_init(&sur40->queue);
567	if (error)
568		goto err_unreg_v4l2;
569
570	sur40->alloc_ctx = vb2_dma_sg_init_ctx(sur40->dev);
571	if (IS_ERR(sur40->alloc_ctx)) {
572		dev_err(sur40->dev, "Can't allocate buffer context");
573		goto err_unreg_v4l2;
574	}
575
576	sur40->vdev = sur40_video_device;
577	sur40->vdev.v4l2_dev = &sur40->v4l2;
578	sur40->vdev.lock = &sur40->lock;
579	sur40->vdev.queue = &sur40->queue;
580	video_set_drvdata(&sur40->vdev, sur40);
581
582	error = video_register_device(&sur40->vdev, VFL_TYPE_GRABBER, -1);
583	if (error) {
584		dev_err(&interface->dev,
585			"Unable to register video subdevice.");
586		goto err_unreg_video;
587	}
588
589	/* we can register the device now, as it is ready */
590	usb_set_intfdata(interface, sur40);
591	dev_dbg(&interface->dev, "%s is now attached\n", DRIVER_DESC);
592
593	return 0;
594
595err_unreg_video:
596	video_unregister_device(&sur40->vdev);
597err_unreg_v4l2:
598	v4l2_device_unregister(&sur40->v4l2);
599err_free_buffer:
600	kfree(sur40->bulk_in_buffer);
601err_free_polldev:
602	input_free_polled_device(sur40->input);
603err_free_dev:
604	kfree(sur40);
605
606	return error;
607}
608
609/* Unregister device & clean up. */
610static void sur40_disconnect(struct usb_interface *interface)
611{
612	struct sur40_state *sur40 = usb_get_intfdata(interface);
613
614	video_unregister_device(&sur40->vdev);
615	v4l2_device_unregister(&sur40->v4l2);
616	vb2_dma_sg_cleanup_ctx(sur40->alloc_ctx);
617
618	input_unregister_polled_device(sur40->input);
619	input_free_polled_device(sur40->input);
620	kfree(sur40->bulk_in_buffer);
621	kfree(sur40);
622
623	usb_set_intfdata(interface, NULL);
624	dev_dbg(&interface->dev, "%s is now disconnected\n", DRIVER_DESC);
625}
626
627/*
628 * Setup the constraints of the queue: besides setting the number of planes
629 * per buffer and the size and allocation context of each plane, it also
630 * checks if sufficient buffers have been allocated. Usually 3 is a good
631 * minimum number: many DMA engines need a minimum of 2 buffers in the
632 * queue and you need to have another available for userspace processing.
633 */
634static int sur40_queue_setup(struct vb2_queue *q, const struct v4l2_format *fmt,
635		       unsigned int *nbuffers, unsigned int *nplanes,
636		       unsigned int sizes[], void *alloc_ctxs[])
637{
638	struct sur40_state *sur40 = vb2_get_drv_priv(q);
639
640	if (q->num_buffers + *nbuffers < 3)
641		*nbuffers = 3 - q->num_buffers;
642
643	if (fmt && fmt->fmt.pix.sizeimage < sur40_video_format.sizeimage)
644		return -EINVAL;
645
646	*nplanes = 1;
647	sizes[0] = fmt ? fmt->fmt.pix.sizeimage : sur40_video_format.sizeimage;
648	alloc_ctxs[0] = sur40->alloc_ctx;
649
650	return 0;
651}
652
653/*
654 * Prepare the buffer for queueing to the DMA engine: check and set the
655 * payload size.
656 */
657static int sur40_buffer_prepare(struct vb2_buffer *vb)
658{
659	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
660	unsigned long size = sur40_video_format.sizeimage;
661
662	if (vb2_plane_size(vb, 0) < size) {
663		dev_err(&sur40->usbdev->dev, "buffer too small (%lu < %lu)\n",
664			 vb2_plane_size(vb, 0), size);
665		return -EINVAL;
666	}
667
668	vb2_set_plane_payload(vb, 0, size);
669	return 0;
670}
671
672/*
673 * Queue this buffer to the DMA engine.
674 */
675static void sur40_buffer_queue(struct vb2_buffer *vb)
676{
677	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
678	struct sur40_buffer *buf = (struct sur40_buffer *)vb;
679
680	spin_lock(&sur40->qlock);
681	list_add_tail(&buf->list, &sur40->buf_list);
682	spin_unlock(&sur40->qlock);
683}
684
685static void return_all_buffers(struct sur40_state *sur40,
686			       enum vb2_buffer_state state)
687{
688	struct sur40_buffer *buf, *node;
689
690	spin_lock(&sur40->qlock);
691	list_for_each_entry_safe(buf, node, &sur40->buf_list, list) {
692		vb2_buffer_done(&buf->vb, state);
693		list_del(&buf->list);
694	}
695	spin_unlock(&sur40->qlock);
696}
697
698/*
699 * Start streaming. First check if the minimum number of buffers have been
700 * queued. If not, then return -ENOBUFS and the vb2 framework will call
701 * this function again the next time a buffer has been queued until enough
702 * buffers are available to actually start the DMA engine.
703 */
704static int sur40_start_streaming(struct vb2_queue *vq, unsigned int count)
705{
706	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
707
708	sur40->sequence = 0;
709	return 0;
710}
711
712/*
713 * Stop the DMA engine. Any remaining buffers in the DMA queue are dequeued
714 * and passed on to the vb2 framework marked as STATE_ERROR.
715 */
716static void sur40_stop_streaming(struct vb2_queue *vq)
717{
718	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
719
720	/* Release all active buffers */
721	return_all_buffers(sur40, VB2_BUF_STATE_ERROR);
722}
723
724/* V4L ioctl */
725static int sur40_vidioc_querycap(struct file *file, void *priv,
726				 struct v4l2_capability *cap)
727{
728	struct sur40_state *sur40 = video_drvdata(file);
729
730	strlcpy(cap->driver, DRIVER_SHORT, sizeof(cap->driver));
731	strlcpy(cap->card, DRIVER_LONG, sizeof(cap->card));
732	usb_make_path(sur40->usbdev, cap->bus_info, sizeof(cap->bus_info));
733	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE |
734		V4L2_CAP_READWRITE |
735		V4L2_CAP_STREAMING;
736	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
737	return 0;
738}
739
740static int sur40_vidioc_enum_input(struct file *file, void *priv,
741				   struct v4l2_input *i)
742{
743	if (i->index != 0)
744		return -EINVAL;
745	i->type = V4L2_INPUT_TYPE_CAMERA;
746	i->std = V4L2_STD_UNKNOWN;
747	strlcpy(i->name, "In-Cell Sensor", sizeof(i->name));
748	i->capabilities = 0;
749	return 0;
750}
751
752static int sur40_vidioc_s_input(struct file *file, void *priv, unsigned int i)
753{
754	return (i == 0) ? 0 : -EINVAL;
755}
756
757static int sur40_vidioc_g_input(struct file *file, void *priv, unsigned int *i)
758{
759	*i = 0;
760	return 0;
761}
762
763static int sur40_vidioc_fmt(struct file *file, void *priv,
764			    struct v4l2_format *f)
765{
766	f->fmt.pix = sur40_video_format;
767	return 0;
768}
769
770static int sur40_vidioc_enum_fmt(struct file *file, void *priv,
771				 struct v4l2_fmtdesc *f)
772{
773	if (f->index != 0)
774		return -EINVAL;
775	strlcpy(f->description, "8-bit greyscale", sizeof(f->description));
776	f->pixelformat = V4L2_PIX_FMT_GREY;
777	f->flags = 0;
778	return 0;
779}
780
781static const struct usb_device_id sur40_table[] = {
782	{ USB_DEVICE(ID_MICROSOFT, ID_SUR40) },  /* Samsung SUR40 */
783	{ }                                      /* terminating null entry */
784};
785MODULE_DEVICE_TABLE(usb, sur40_table);
786
787/* V4L2 structures */
788static const struct vb2_ops sur40_queue_ops = {
789	.queue_setup		= sur40_queue_setup,
790	.buf_prepare		= sur40_buffer_prepare,
791	.buf_queue		= sur40_buffer_queue,
792	.start_streaming	= sur40_start_streaming,
793	.stop_streaming		= sur40_stop_streaming,
794	.wait_prepare		= vb2_ops_wait_prepare,
795	.wait_finish		= vb2_ops_wait_finish,
796};
797
798static const struct vb2_queue sur40_queue = {
799	.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
800	/*
801	 * VB2_USERPTR in currently not enabled: passing a user pointer to
802	 * dma-sg will result in segment sizes that are not a multiple of
803	 * 512 bytes, which is required by the host controller.
804	*/
805	.io_modes = VB2_MMAP | VB2_READ | VB2_DMABUF,
806	.buf_struct_size = sizeof(struct sur40_buffer),
807	.ops = &sur40_queue_ops,
808	.mem_ops = &vb2_dma_sg_memops,
809	.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC,
810	.min_buffers_needed = 3,
811};
812
813static const struct v4l2_file_operations sur40_video_fops = {
814	.owner = THIS_MODULE,
815	.open = v4l2_fh_open,
816	.release = vb2_fop_release,
817	.unlocked_ioctl = video_ioctl2,
818	.read = vb2_fop_read,
819	.mmap = vb2_fop_mmap,
820	.poll = vb2_fop_poll,
821};
822
823static const struct v4l2_ioctl_ops sur40_video_ioctl_ops = {
824
825	.vidioc_querycap	= sur40_vidioc_querycap,
826
827	.vidioc_enum_fmt_vid_cap = sur40_vidioc_enum_fmt,
828	.vidioc_try_fmt_vid_cap	= sur40_vidioc_fmt,
829	.vidioc_s_fmt_vid_cap	= sur40_vidioc_fmt,
830	.vidioc_g_fmt_vid_cap	= sur40_vidioc_fmt,
831
832	.vidioc_enum_input	= sur40_vidioc_enum_input,
833	.vidioc_g_input		= sur40_vidioc_g_input,
834	.vidioc_s_input		= sur40_vidioc_s_input,
835
836	.vidioc_reqbufs		= vb2_ioctl_reqbufs,
837	.vidioc_create_bufs	= vb2_ioctl_create_bufs,
838	.vidioc_querybuf	= vb2_ioctl_querybuf,
839	.vidioc_qbuf		= vb2_ioctl_qbuf,
840	.vidioc_dqbuf		= vb2_ioctl_dqbuf,
841	.vidioc_expbuf		= vb2_ioctl_expbuf,
842
843	.vidioc_streamon	= vb2_ioctl_streamon,
844	.vidioc_streamoff	= vb2_ioctl_streamoff,
845};
846
847static const struct video_device sur40_video_device = {
848	.name = DRIVER_LONG,
849	.fops = &sur40_video_fops,
850	.ioctl_ops = &sur40_video_ioctl_ops,
851	.release = video_device_release_empty,
852};
853
854static const struct v4l2_pix_format sur40_video_format = {
855	.pixelformat = V4L2_PIX_FMT_GREY,
856	.width  = SENSOR_RES_X / 2,
857	.height = SENSOR_RES_Y / 2,
858	.field = V4L2_FIELD_NONE,
859	.colorspace = V4L2_COLORSPACE_SRGB,
860	.bytesperline = SENSOR_RES_X / 2,
861	.sizeimage = (SENSOR_RES_X/2) * (SENSOR_RES_Y/2),
862};
863
864/* USB-specific object needed to register this driver with the USB subsystem. */
865static struct usb_driver sur40_driver = {
866	.name = DRIVER_SHORT,
867	.probe = sur40_probe,
868	.disconnect = sur40_disconnect,
869	.id_table = sur40_table,
870};
871
872module_usb_driver(sur40_driver);
873
874MODULE_AUTHOR(DRIVER_AUTHOR);
875MODULE_DESCRIPTION(DRIVER_DESC);
876MODULE_LICENSE("GPL");
877