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-v4l2.h>
42#include <media/videobuf2-dma-sg.h>
43
44/* read 512 bytes from endpoint 0x86 -> get header + blobs */
45struct sur40_header {
46
47	__le16 type;       /* always 0x0001 */
48	__le16 count;      /* count of blobs (if 0: continue prev. packet) */
49
50	__le32 packet_id;  /* unique ID for all packets in one frame */
51
52	__le32 timestamp;  /* milliseconds (inc. by 16 or 17 each frame) */
53	__le32 unknown;    /* "epoch?" always 02/03 00 00 00 */
54
55} __packed;
56
57struct sur40_blob {
58
59	__le16 blob_id;
60
61	u8 action;         /* 0x02 = enter/exit, 0x03 = update (?) */
62	u8 unknown;        /* always 0x01 or 0x02 (no idea what this is?) */
63
64	__le16 bb_pos_x;   /* upper left corner of bounding box */
65	__le16 bb_pos_y;
66
67	__le16 bb_size_x;  /* size of bounding box */
68	__le16 bb_size_y;
69
70	__le16 pos_x;      /* finger tip position */
71	__le16 pos_y;
72
73	__le16 ctr_x;      /* centroid position */
74	__le16 ctr_y;
75
76	__le16 axis_x;     /* somehow related to major/minor axis, mostly: */
77	__le16 axis_y;     /* axis_x == bb_size_y && axis_y == bb_size_x */
78
79	__le32 angle;      /* orientation in radians relative to x axis -
80	                      actually an IEEE754 float, don't use in kernel */
81
82	__le32 area;       /* size in pixels/pressure (?) */
83
84	u8 padding[32];
85
86} __packed;
87
88/* combined header/blob data */
89struct sur40_data {
90	struct sur40_header header;
91	struct sur40_blob   blobs[];
92} __packed;
93
94/* read 512 bytes from endpoint 0x82 -> get header below
95 * continue reading 16k blocks until header.size bytes read */
96struct sur40_image_header {
97	__le32 magic;     /* "SUBF" */
98	__le32 packet_id;
99	__le32 size;      /* always 0x0007e900 = 960x540 */
100	__le32 timestamp; /* milliseconds (increases by 16 or 17 each frame) */
101	__le32 unknown;   /* "epoch?" always 02/03 00 00 00 */
102} __packed;
103
104/* version information */
105#define DRIVER_SHORT   "sur40"
106#define DRIVER_LONG    "Samsung SUR40"
107#define DRIVER_AUTHOR  "Florian 'floe' Echtler <floe@butterbrot.org>"
108#define DRIVER_DESC    "Surface2.0/SUR40/PixelSense input driver"
109
110/* vendor and device IDs */
111#define ID_MICROSOFT 0x045e
112#define ID_SUR40     0x0775
113
114/* sensor resolution */
115#define SENSOR_RES_X 1920
116#define SENSOR_RES_Y 1080
117
118/* touch data endpoint */
119#define TOUCH_ENDPOINT 0x86
120
121/* video data endpoint */
122#define VIDEO_ENDPOINT 0x82
123
124/* video header fields */
125#define VIDEO_HEADER_MAGIC 0x46425553
126#define VIDEO_PACKET_SIZE  16384
127
128/* polling interval (ms) */
129#define POLL_INTERVAL 4
130
131/* maximum number of contacts FIXME: this is a guess? */
132#define MAX_CONTACTS 64
133
134/* control commands */
135#define SUR40_GET_VERSION 0xb0 /* 12 bytes string    */
136#define SUR40_UNKNOWN1    0xb3 /*  5 bytes           */
137#define SUR40_UNKNOWN2    0xc1 /* 24 bytes           */
138
139#define SUR40_GET_STATE   0xc5 /*  4 bytes state (?) */
140#define SUR40_GET_SENSORS 0xb1 /*  8 bytes sensors   */
141
142/* master device state */
143struct sur40_state {
144
145	struct usb_device *usbdev;
146	struct device *dev;
147	struct input_polled_dev *input;
148
149	struct v4l2_device v4l2;
150	struct video_device vdev;
151	struct mutex lock;
152
153	struct vb2_queue queue;
154	struct vb2_alloc_ctx *alloc_ctx;
155	struct list_head buf_list;
156	spinlock_t qlock;
157	int sequence;
158
159	struct sur40_data *bulk_in_buffer;
160	size_t bulk_in_size;
161	u8 bulk_in_epaddr;
162
163	char phys[64];
164};
165
166struct sur40_buffer {
167	struct vb2_v4l2_buffer vb;
168	struct list_head list;
169};
170
171/* forward declarations */
172static const struct video_device sur40_video_device;
173static const struct v4l2_pix_format sur40_video_format;
174static const struct vb2_queue sur40_queue;
175static void sur40_process_video(struct sur40_state *sur40);
176
177/*
178 * Note: an earlier, non-public version of this driver used USB_RECIP_ENDPOINT
179 * here by mistake which is very likely to have corrupted the firmware EEPROM
180 * on two separate SUR40 devices. Thanks to Alan Stern who spotted this bug.
181 * Should you ever run into a similar problem, the background story to this
182 * incident and instructions on how to fix the corrupted EEPROM are available
183 * at https://floe.butterbrot.org/matrix/hacking/surface/brick.html
184*/
185
186/* command wrapper */
187static int sur40_command(struct sur40_state *dev,
188			 u8 command, u16 index, void *buffer, u16 size)
189{
190	return usb_control_msg(dev->usbdev, usb_rcvctrlpipe(dev->usbdev, 0),
191			       command,
192			       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
193			       0x00, index, buffer, size, 1000);
194}
195
196/* Initialization routine, called from sur40_open */
197static int sur40_init(struct sur40_state *dev)
198{
199	int result;
200	u8 buffer[24];
201
202	/* stupidly replay the original MS driver init sequence */
203	result = sur40_command(dev, SUR40_GET_VERSION, 0x00, buffer, 12);
204	if (result < 0)
205		return result;
206
207	result = sur40_command(dev, SUR40_GET_VERSION, 0x01, buffer, 12);
208	if (result < 0)
209		return result;
210
211	result = sur40_command(dev, SUR40_GET_VERSION, 0x02, buffer, 12);
212	if (result < 0)
213		return result;
214
215	result = sur40_command(dev, SUR40_UNKNOWN2,    0x00, buffer, 24);
216	if (result < 0)
217		return result;
218
219	result = sur40_command(dev, SUR40_UNKNOWN1,    0x00, buffer,  5);
220	if (result < 0)
221		return result;
222
223	result = sur40_command(dev, SUR40_GET_VERSION, 0x03, buffer, 12);
224
225	/*
226	 * Discard the result buffer - no known data inside except
227	 * some version strings, maybe extract these sometime...
228	 */
229
230	return result;
231}
232
233/*
234 * Callback routines from input_polled_dev
235 */
236
237/* Enable the device, polling will now start. */
238static void sur40_open(struct input_polled_dev *polldev)
239{
240	struct sur40_state *sur40 = polldev->private;
241
242	dev_dbg(sur40->dev, "open\n");
243	sur40_init(sur40);
244}
245
246/* Disable device, polling has stopped. */
247static void sur40_close(struct input_polled_dev *polldev)
248{
249	struct sur40_state *sur40 = polldev->private;
250
251	dev_dbg(sur40->dev, "close\n");
252	/*
253	 * There is no known way to stop the device, so we simply
254	 * stop polling.
255	 */
256}
257
258/*
259 * This function is called when a whole contact has been processed,
260 * so that it can assign it to a slot and store the data there.
261 */
262static void sur40_report_blob(struct sur40_blob *blob, struct input_dev *input)
263{
264	int wide, major, minor;
265
266	int bb_size_x = le16_to_cpu(blob->bb_size_x);
267	int bb_size_y = le16_to_cpu(blob->bb_size_y);
268
269	int pos_x = le16_to_cpu(blob->pos_x);
270	int pos_y = le16_to_cpu(blob->pos_y);
271
272	int ctr_x = le16_to_cpu(blob->ctr_x);
273	int ctr_y = le16_to_cpu(blob->ctr_y);
274
275	int slotnum = input_mt_get_slot_by_key(input, blob->blob_id);
276	if (slotnum < 0 || slotnum >= MAX_CONTACTS)
277		return;
278
279	input_mt_slot(input, slotnum);
280	input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
281	wide = (bb_size_x > bb_size_y);
282	major = max(bb_size_x, bb_size_y);
283	minor = min(bb_size_x, bb_size_y);
284
285	input_report_abs(input, ABS_MT_POSITION_X, pos_x);
286	input_report_abs(input, ABS_MT_POSITION_Y, pos_y);
287	input_report_abs(input, ABS_MT_TOOL_X, ctr_x);
288	input_report_abs(input, ABS_MT_TOOL_Y, ctr_y);
289
290	/* TODO: use a better orientation measure */
291	input_report_abs(input, ABS_MT_ORIENTATION, wide);
292	input_report_abs(input, ABS_MT_TOUCH_MAJOR, major);
293	input_report_abs(input, ABS_MT_TOUCH_MINOR, minor);
294}
295
296/* core function: poll for new input data */
297static void sur40_poll(struct input_polled_dev *polldev)
298{
299	struct sur40_state *sur40 = polldev->private;
300	struct input_dev *input = polldev->input;
301	int result, bulk_read, need_blobs, packet_blobs, i;
302	u32 uninitialized_var(packet_id);
303
304	struct sur40_header *header = &sur40->bulk_in_buffer->header;
305	struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0];
306
307	dev_dbg(sur40->dev, "poll\n");
308
309	need_blobs = -1;
310
311	do {
312
313		/* perform a blocking bulk read to get data from the device */
314		result = usb_bulk_msg(sur40->usbdev,
315			usb_rcvbulkpipe(sur40->usbdev, sur40->bulk_in_epaddr),
316			sur40->bulk_in_buffer, sur40->bulk_in_size,
317			&bulk_read, 1000);
318
319		dev_dbg(sur40->dev, "received %d bytes\n", bulk_read);
320
321		if (result < 0) {
322			dev_err(sur40->dev, "error in usb_bulk_read\n");
323			return;
324		}
325
326		result = bulk_read - sizeof(struct sur40_header);
327
328		if (result % sizeof(struct sur40_blob) != 0) {
329			dev_err(sur40->dev, "transfer size mismatch\n");
330			return;
331		}
332
333		/* first packet? */
334		if (need_blobs == -1) {
335			need_blobs = le16_to_cpu(header->count);
336			dev_dbg(sur40->dev, "need %d blobs\n", need_blobs);
337			packet_id = le32_to_cpu(header->packet_id);
338		}
339
340		/*
341		 * Sanity check. when video data is also being retrieved, the
342		 * packet ID will usually increase in the middle of a series
343		 * instead of at the end.
344		 */
345		if (packet_id != header->packet_id)
346			dev_dbg(sur40->dev, "packet ID mismatch\n");
347
348		packet_blobs = result / sizeof(struct sur40_blob);
349		dev_dbg(sur40->dev, "received %d blobs\n", packet_blobs);
350
351		/* packets always contain at least 4 blobs, even if empty */
352		if (packet_blobs > need_blobs)
353			packet_blobs = need_blobs;
354
355		for (i = 0; i < packet_blobs; i++) {
356			need_blobs--;
357			dev_dbg(sur40->dev, "processing blob\n");
358			sur40_report_blob(&(inblob[i]), input);
359		}
360
361	} while (need_blobs > 0);
362
363	input_mt_sync_frame(input);
364	input_sync(input);
365
366	sur40_process_video(sur40);
367}
368
369/* deal with video data */
370static void sur40_process_video(struct sur40_state *sur40)
371{
372
373	struct sur40_image_header *img = (void *)(sur40->bulk_in_buffer);
374	struct sur40_buffer *new_buf;
375	struct usb_sg_request sgr;
376	struct sg_table *sgt;
377	int result, bulk_read;
378
379	if (!vb2_start_streaming_called(&sur40->queue))
380		return;
381
382	/* get a new buffer from the list */
383	spin_lock(&sur40->qlock);
384	if (list_empty(&sur40->buf_list)) {
385		dev_dbg(sur40->dev, "buffer queue empty\n");
386		spin_unlock(&sur40->qlock);
387		return;
388	}
389	new_buf = list_entry(sur40->buf_list.next, struct sur40_buffer, list);
390	list_del(&new_buf->list);
391	spin_unlock(&sur40->qlock);
392
393	dev_dbg(sur40->dev, "buffer acquired\n");
394
395	/* retrieve data via bulk read */
396	result = usb_bulk_msg(sur40->usbdev,
397			usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT),
398			sur40->bulk_in_buffer, sur40->bulk_in_size,
399			&bulk_read, 1000);
400
401	if (result < 0) {
402		dev_err(sur40->dev, "error in usb_bulk_read\n");
403		goto err_poll;
404	}
405
406	if (bulk_read != sizeof(struct sur40_image_header)) {
407		dev_err(sur40->dev, "received %d bytes (%zd expected)\n",
408			bulk_read, sizeof(struct sur40_image_header));
409		goto err_poll;
410	}
411
412	if (le32_to_cpu(img->magic) != VIDEO_HEADER_MAGIC) {
413		dev_err(sur40->dev, "image magic mismatch\n");
414		goto err_poll;
415	}
416
417	if (le32_to_cpu(img->size) != sur40_video_format.sizeimage) {
418		dev_err(sur40->dev, "image size mismatch\n");
419		goto err_poll;
420	}
421
422	dev_dbg(sur40->dev, "header acquired\n");
423
424	sgt = vb2_dma_sg_plane_desc(&new_buf->vb.vb2_buf, 0);
425
426	result = usb_sg_init(&sgr, sur40->usbdev,
427		usb_rcvbulkpipe(sur40->usbdev, VIDEO_ENDPOINT), 0,
428		sgt->sgl, sgt->nents, sur40_video_format.sizeimage, 0);
429	if (result < 0) {
430		dev_err(sur40->dev, "error %d in usb_sg_init\n", result);
431		goto err_poll;
432	}
433
434	usb_sg_wait(&sgr);
435	if (sgr.status < 0) {
436		dev_err(sur40->dev, "error %d in usb_sg_wait\n", sgr.status);
437		goto err_poll;
438	}
439
440	dev_dbg(sur40->dev, "image acquired\n");
441
442	/* return error if streaming was stopped in the meantime */
443	if (sur40->sequence == -1)
444		goto err_poll;
445
446	/* mark as finished */
447	v4l2_get_timestamp(&new_buf->vb.timestamp);
448	new_buf->vb.sequence = sur40->sequence++;
449	new_buf->vb.field = V4L2_FIELD_NONE;
450	vb2_buffer_done(&new_buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
451	dev_dbg(sur40->dev, "buffer marked done\n");
452	return;
453
454err_poll:
455	vb2_buffer_done(&new_buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
456}
457
458/* Initialize input device parameters. */
459static void sur40_input_setup(struct input_dev *input_dev)
460{
461	__set_bit(EV_KEY, input_dev->evbit);
462	__set_bit(EV_ABS, input_dev->evbit);
463
464	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
465			     0, SENSOR_RES_X, 0, 0);
466	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
467			     0, SENSOR_RES_Y, 0, 0);
468
469	input_set_abs_params(input_dev, ABS_MT_TOOL_X,
470			     0, SENSOR_RES_X, 0, 0);
471	input_set_abs_params(input_dev, ABS_MT_TOOL_Y,
472			     0, SENSOR_RES_Y, 0, 0);
473
474	/* max value unknown, but major/minor axis
475	 * can never be larger than screen */
476	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR,
477			     0, SENSOR_RES_X, 0, 0);
478	input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR,
479			     0, SENSOR_RES_Y, 0, 0);
480
481	input_set_abs_params(input_dev, ABS_MT_ORIENTATION, 0, 1, 0, 0);
482
483	input_mt_init_slots(input_dev, MAX_CONTACTS,
484			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
485}
486
487/* Check candidate USB interface. */
488static int sur40_probe(struct usb_interface *interface,
489		       const struct usb_device_id *id)
490{
491	struct usb_device *usbdev = interface_to_usbdev(interface);
492	struct sur40_state *sur40;
493	struct usb_host_interface *iface_desc;
494	struct usb_endpoint_descriptor *endpoint;
495	struct input_polled_dev *poll_dev;
496	int error;
497
498	/* Check if we really have the right interface. */
499	iface_desc = &interface->altsetting[0];
500	if (iface_desc->desc.bInterfaceClass != 0xFF)
501		return -ENODEV;
502
503	/* Use endpoint #4 (0x86). */
504	endpoint = &iface_desc->endpoint[4].desc;
505	if (endpoint->bEndpointAddress != TOUCH_ENDPOINT)
506		return -ENODEV;
507
508	/* Allocate memory for our device state and initialize it. */
509	sur40 = kzalloc(sizeof(struct sur40_state), GFP_KERNEL);
510	if (!sur40)
511		return -ENOMEM;
512
513	poll_dev = input_allocate_polled_device();
514	if (!poll_dev) {
515		error = -ENOMEM;
516		goto err_free_dev;
517	}
518
519	/* initialize locks/lists */
520	INIT_LIST_HEAD(&sur40->buf_list);
521	spin_lock_init(&sur40->qlock);
522	mutex_init(&sur40->lock);
523
524	/* Set up polled input device control structure */
525	poll_dev->private = sur40;
526	poll_dev->poll_interval = POLL_INTERVAL;
527	poll_dev->open = sur40_open;
528	poll_dev->poll = sur40_poll;
529	poll_dev->close = sur40_close;
530
531	/* Set up regular input device structure */
532	sur40_input_setup(poll_dev->input);
533
534	poll_dev->input->name = DRIVER_LONG;
535	usb_to_input_id(usbdev, &poll_dev->input->id);
536	usb_make_path(usbdev, sur40->phys, sizeof(sur40->phys));
537	strlcat(sur40->phys, "/input0", sizeof(sur40->phys));
538	poll_dev->input->phys = sur40->phys;
539	poll_dev->input->dev.parent = &interface->dev;
540
541	sur40->usbdev = usbdev;
542	sur40->dev = &interface->dev;
543	sur40->input = poll_dev;
544
545	/* use the bulk-in endpoint tested above */
546	sur40->bulk_in_size = usb_endpoint_maxp(endpoint);
547	sur40->bulk_in_epaddr = endpoint->bEndpointAddress;
548	sur40->bulk_in_buffer = kmalloc(sur40->bulk_in_size, GFP_KERNEL);
549	if (!sur40->bulk_in_buffer) {
550		dev_err(&interface->dev, "Unable to allocate input buffer.");
551		error = -ENOMEM;
552		goto err_free_polldev;
553	}
554
555	/* register the polled input device */
556	error = input_register_polled_device(poll_dev);
557	if (error) {
558		dev_err(&interface->dev,
559			"Unable to register polled input device.");
560		goto err_free_buffer;
561	}
562
563	/* register the video master device */
564	snprintf(sur40->v4l2.name, sizeof(sur40->v4l2.name), "%s", DRIVER_LONG);
565	error = v4l2_device_register(sur40->dev, &sur40->v4l2);
566	if (error) {
567		dev_err(&interface->dev,
568			"Unable to register video master device.");
569		goto err_unreg_v4l2;
570	}
571
572	/* initialize the lock and subdevice */
573	sur40->queue = sur40_queue;
574	sur40->queue.drv_priv = sur40;
575	sur40->queue.lock = &sur40->lock;
576
577	/* initialize the queue */
578	error = vb2_queue_init(&sur40->queue);
579	if (error)
580		goto err_unreg_v4l2;
581
582	sur40->alloc_ctx = vb2_dma_sg_init_ctx(sur40->dev);
583	if (IS_ERR(sur40->alloc_ctx)) {
584		dev_err(sur40->dev, "Can't allocate buffer context");
585		error = PTR_ERR(sur40->alloc_ctx);
586		goto err_unreg_v4l2;
587	}
588
589	sur40->vdev = sur40_video_device;
590	sur40->vdev.v4l2_dev = &sur40->v4l2;
591	sur40->vdev.lock = &sur40->lock;
592	sur40->vdev.queue = &sur40->queue;
593	video_set_drvdata(&sur40->vdev, sur40);
594
595	error = video_register_device(&sur40->vdev, VFL_TYPE_GRABBER, -1);
596	if (error) {
597		dev_err(&interface->dev,
598			"Unable to register video subdevice.");
599		goto err_unreg_video;
600	}
601
602	/* we can register the device now, as it is ready */
603	usb_set_intfdata(interface, sur40);
604	dev_dbg(&interface->dev, "%s is now attached\n", DRIVER_DESC);
605
606	return 0;
607
608err_unreg_video:
609	video_unregister_device(&sur40->vdev);
610err_unreg_v4l2:
611	v4l2_device_unregister(&sur40->v4l2);
612err_free_buffer:
613	kfree(sur40->bulk_in_buffer);
614err_free_polldev:
615	input_free_polled_device(sur40->input);
616err_free_dev:
617	kfree(sur40);
618
619	return error;
620}
621
622/* Unregister device & clean up. */
623static void sur40_disconnect(struct usb_interface *interface)
624{
625	struct sur40_state *sur40 = usb_get_intfdata(interface);
626
627	video_unregister_device(&sur40->vdev);
628	v4l2_device_unregister(&sur40->v4l2);
629	vb2_dma_sg_cleanup_ctx(sur40->alloc_ctx);
630
631	input_unregister_polled_device(sur40->input);
632	input_free_polled_device(sur40->input);
633	kfree(sur40->bulk_in_buffer);
634	kfree(sur40);
635
636	usb_set_intfdata(interface, NULL);
637	dev_dbg(&interface->dev, "%s is now disconnected\n", DRIVER_DESC);
638}
639
640/*
641 * Setup the constraints of the queue: besides setting the number of planes
642 * per buffer and the size and allocation context of each plane, it also
643 * checks if sufficient buffers have been allocated. Usually 3 is a good
644 * minimum number: many DMA engines need a minimum of 2 buffers in the
645 * queue and you need to have another available for userspace processing.
646 */
647static int sur40_queue_setup(struct vb2_queue *q, const void *parg,
648		       unsigned int *nbuffers, unsigned int *nplanes,
649		       unsigned int sizes[], void *alloc_ctxs[])
650{
651	const struct v4l2_format *fmt = parg;
652	struct sur40_state *sur40 = vb2_get_drv_priv(q);
653
654	if (q->num_buffers + *nbuffers < 3)
655		*nbuffers = 3 - q->num_buffers;
656
657	if (fmt && fmt->fmt.pix.sizeimage < sur40_video_format.sizeimage)
658		return -EINVAL;
659
660	*nplanes = 1;
661	sizes[0] = fmt ? fmt->fmt.pix.sizeimage : sur40_video_format.sizeimage;
662	alloc_ctxs[0] = sur40->alloc_ctx;
663
664	return 0;
665}
666
667/*
668 * Prepare the buffer for queueing to the DMA engine: check and set the
669 * payload size.
670 */
671static int sur40_buffer_prepare(struct vb2_buffer *vb)
672{
673	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
674	unsigned long size = sur40_video_format.sizeimage;
675
676	if (vb2_plane_size(vb, 0) < size) {
677		dev_err(&sur40->usbdev->dev, "buffer too small (%lu < %lu)\n",
678			 vb2_plane_size(vb, 0), size);
679		return -EINVAL;
680	}
681
682	vb2_set_plane_payload(vb, 0, size);
683	return 0;
684}
685
686/*
687 * Queue this buffer to the DMA engine.
688 */
689static void sur40_buffer_queue(struct vb2_buffer *vb)
690{
691	struct sur40_state *sur40 = vb2_get_drv_priv(vb->vb2_queue);
692	struct sur40_buffer *buf = (struct sur40_buffer *)vb;
693
694	spin_lock(&sur40->qlock);
695	list_add_tail(&buf->list, &sur40->buf_list);
696	spin_unlock(&sur40->qlock);
697}
698
699static void return_all_buffers(struct sur40_state *sur40,
700			       enum vb2_buffer_state state)
701{
702	struct sur40_buffer *buf, *node;
703
704	spin_lock(&sur40->qlock);
705	list_for_each_entry_safe(buf, node, &sur40->buf_list, list) {
706		vb2_buffer_done(&buf->vb.vb2_buf, state);
707		list_del(&buf->list);
708	}
709	spin_unlock(&sur40->qlock);
710}
711
712/*
713 * Start streaming. First check if the minimum number of buffers have been
714 * queued. If not, then return -ENOBUFS and the vb2 framework will call
715 * this function again the next time a buffer has been queued until enough
716 * buffers are available to actually start the DMA engine.
717 */
718static int sur40_start_streaming(struct vb2_queue *vq, unsigned int count)
719{
720	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
721
722	sur40->sequence = 0;
723	return 0;
724}
725
726/*
727 * Stop the DMA engine. Any remaining buffers in the DMA queue are dequeued
728 * and passed on to the vb2 framework marked as STATE_ERROR.
729 */
730static void sur40_stop_streaming(struct vb2_queue *vq)
731{
732	struct sur40_state *sur40 = vb2_get_drv_priv(vq);
733	sur40->sequence = -1;
734
735	/* Release all active buffers */
736	return_all_buffers(sur40, VB2_BUF_STATE_ERROR);
737}
738
739/* V4L ioctl */
740static int sur40_vidioc_querycap(struct file *file, void *priv,
741				 struct v4l2_capability *cap)
742{
743	struct sur40_state *sur40 = video_drvdata(file);
744
745	strlcpy(cap->driver, DRIVER_SHORT, sizeof(cap->driver));
746	strlcpy(cap->card, DRIVER_LONG, sizeof(cap->card));
747	usb_make_path(sur40->usbdev, cap->bus_info, sizeof(cap->bus_info));
748	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE |
749		V4L2_CAP_READWRITE |
750		V4L2_CAP_STREAMING;
751	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
752	return 0;
753}
754
755static int sur40_vidioc_enum_input(struct file *file, void *priv,
756				   struct v4l2_input *i)
757{
758	if (i->index != 0)
759		return -EINVAL;
760	i->type = V4L2_INPUT_TYPE_CAMERA;
761	i->std = V4L2_STD_UNKNOWN;
762	strlcpy(i->name, "In-Cell Sensor", sizeof(i->name));
763	i->capabilities = 0;
764	return 0;
765}
766
767static int sur40_vidioc_s_input(struct file *file, void *priv, unsigned int i)
768{
769	return (i == 0) ? 0 : -EINVAL;
770}
771
772static int sur40_vidioc_g_input(struct file *file, void *priv, unsigned int *i)
773{
774	*i = 0;
775	return 0;
776}
777
778static int sur40_vidioc_fmt(struct file *file, void *priv,
779			    struct v4l2_format *f)
780{
781	f->fmt.pix = sur40_video_format;
782	return 0;
783}
784
785static int sur40_vidioc_enum_fmt(struct file *file, void *priv,
786				 struct v4l2_fmtdesc *f)
787{
788	if (f->index != 0)
789		return -EINVAL;
790	strlcpy(f->description, "8-bit greyscale", sizeof(f->description));
791	f->pixelformat = V4L2_PIX_FMT_GREY;
792	f->flags = 0;
793	return 0;
794}
795
796static int sur40_vidioc_enum_framesizes(struct file *file, void *priv,
797					struct v4l2_frmsizeenum *f)
798{
799	if ((f->index != 0) || (f->pixel_format != V4L2_PIX_FMT_GREY))
800		return -EINVAL;
801
802	f->type = V4L2_FRMSIZE_TYPE_DISCRETE;
803	f->discrete.width  = sur40_video_format.width;
804	f->discrete.height = sur40_video_format.height;
805	return 0;
806}
807
808static int sur40_vidioc_enum_frameintervals(struct file *file, void *priv,
809					    struct v4l2_frmivalenum *f)
810{
811	if ((f->index > 1) || (f->pixel_format != V4L2_PIX_FMT_GREY)
812		|| (f->width  != sur40_video_format.width)
813		|| (f->height != sur40_video_format.height))
814			return -EINVAL;
815
816	f->type = V4L2_FRMIVAL_TYPE_DISCRETE;
817	f->discrete.denominator  = 60/(f->index+1);
818	f->discrete.numerator = 1;
819	return 0;
820}
821
822
823static const struct usb_device_id sur40_table[] = {
824	{ USB_DEVICE(ID_MICROSOFT, ID_SUR40) },  /* Samsung SUR40 */
825	{ }                                      /* terminating null entry */
826};
827MODULE_DEVICE_TABLE(usb, sur40_table);
828
829/* V4L2 structures */
830static const struct vb2_ops sur40_queue_ops = {
831	.queue_setup		= sur40_queue_setup,
832	.buf_prepare		= sur40_buffer_prepare,
833	.buf_queue		= sur40_buffer_queue,
834	.start_streaming	= sur40_start_streaming,
835	.stop_streaming		= sur40_stop_streaming,
836	.wait_prepare		= vb2_ops_wait_prepare,
837	.wait_finish		= vb2_ops_wait_finish,
838};
839
840static const struct vb2_queue sur40_queue = {
841	.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
842	/*
843	 * VB2_USERPTR in currently not enabled: passing a user pointer to
844	 * dma-sg will result in segment sizes that are not a multiple of
845	 * 512 bytes, which is required by the host controller.
846	*/
847	.io_modes = VB2_MMAP | VB2_READ | VB2_DMABUF,
848	.buf_struct_size = sizeof(struct sur40_buffer),
849	.ops = &sur40_queue_ops,
850	.mem_ops = &vb2_dma_sg_memops,
851	.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC,
852	.min_buffers_needed = 3,
853};
854
855static const struct v4l2_file_operations sur40_video_fops = {
856	.owner = THIS_MODULE,
857	.open = v4l2_fh_open,
858	.release = vb2_fop_release,
859	.unlocked_ioctl = video_ioctl2,
860	.read = vb2_fop_read,
861	.mmap = vb2_fop_mmap,
862	.poll = vb2_fop_poll,
863};
864
865static const struct v4l2_ioctl_ops sur40_video_ioctl_ops = {
866
867	.vidioc_querycap	= sur40_vidioc_querycap,
868
869	.vidioc_enum_fmt_vid_cap = sur40_vidioc_enum_fmt,
870	.vidioc_try_fmt_vid_cap	= sur40_vidioc_fmt,
871	.vidioc_s_fmt_vid_cap	= sur40_vidioc_fmt,
872	.vidioc_g_fmt_vid_cap	= sur40_vidioc_fmt,
873
874	.vidioc_enum_framesizes = sur40_vidioc_enum_framesizes,
875	.vidioc_enum_frameintervals = sur40_vidioc_enum_frameintervals,
876
877	.vidioc_enum_input	= sur40_vidioc_enum_input,
878	.vidioc_g_input		= sur40_vidioc_g_input,
879	.vidioc_s_input		= sur40_vidioc_s_input,
880
881	.vidioc_reqbufs		= vb2_ioctl_reqbufs,
882	.vidioc_create_bufs	= vb2_ioctl_create_bufs,
883	.vidioc_querybuf	= vb2_ioctl_querybuf,
884	.vidioc_qbuf		= vb2_ioctl_qbuf,
885	.vidioc_dqbuf		= vb2_ioctl_dqbuf,
886	.vidioc_expbuf		= vb2_ioctl_expbuf,
887
888	.vidioc_streamon	= vb2_ioctl_streamon,
889	.vidioc_streamoff	= vb2_ioctl_streamoff,
890};
891
892static const struct video_device sur40_video_device = {
893	.name = DRIVER_LONG,
894	.fops = &sur40_video_fops,
895	.ioctl_ops = &sur40_video_ioctl_ops,
896	.release = video_device_release_empty,
897};
898
899static const struct v4l2_pix_format sur40_video_format = {
900	.pixelformat = V4L2_PIX_FMT_GREY,
901	.width  = SENSOR_RES_X / 2,
902	.height = SENSOR_RES_Y / 2,
903	.field = V4L2_FIELD_NONE,
904	.colorspace = V4L2_COLORSPACE_SRGB,
905	.bytesperline = SENSOR_RES_X / 2,
906	.sizeimage = (SENSOR_RES_X/2) * (SENSOR_RES_Y/2),
907};
908
909/* USB-specific object needed to register this driver with the USB subsystem. */
910static struct usb_driver sur40_driver = {
911	.name = DRIVER_SHORT,
912	.probe = sur40_probe,
913	.disconnect = sur40_disconnect,
914	.id_table = sur40_table,
915};
916
917module_usb_driver(sur40_driver);
918
919MODULE_AUTHOR(DRIVER_AUTHOR);
920MODULE_DESCRIPTION(DRIVER_DESC);
921MODULE_LICENSE("GPL");
922