1// SPDX-License-Identifier: GPL-2.0+
2/*
3 *  HID driver for UC-Logic devices not fully compliant with HID standard
4 *  - tablet initialization and parameter retrieval
5 *
6 *  Copyright (c) 2018 Nikolai Kondrashov
7 */
8
9/*
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 */
15
16#include "hid-uclogic-params.h"
17#include "hid-uclogic-rdesc.h"
18#include "usbhid/usbhid.h"
19#include "hid-ids.h"
20#include <linux/ctype.h>
21#include <asm/unaligned.h>
22
23/**
24 * Convert a pen in-range reporting type to a string.
25 *
26 * @inrange:	The in-range reporting type to convert.
27 *
28 * Returns:
29 *	The string representing the type, or NULL if the type is unknown.
30 */
31const char *uclogic_params_pen_inrange_to_str(
32			enum uclogic_params_pen_inrange inrange)
33{
34	switch (inrange) {
35	case UCLOGIC_PARAMS_PEN_INRANGE_NORMAL:
36		return "normal";
37	case UCLOGIC_PARAMS_PEN_INRANGE_INVERTED:
38		return "inverted";
39	case UCLOGIC_PARAMS_PEN_INRANGE_NONE:
40		return "none";
41	default:
42		return NULL;
43	}
44}
45
46/**
47 * uclogic_params_get_str_desc - retrieve a string descriptor from a HID
48 * device interface, putting it into a kmalloc-allocated buffer as is, without
49 * character encoding conversion.
50 *
51 * @pbuf:	Location for the kmalloc-allocated buffer pointer containing
52 *		the retrieved descriptor. Not modified in case of error.
53 *		Can be NULL to have retrieved descriptor discarded.
54 * @hdev:	The HID device of the tablet interface to retrieve the string
55 *		descriptor from. Cannot be NULL.
56 * @idx:	Index of the string descriptor to request from the device.
57 * @len:	Length of the buffer to allocate and the data to retrieve.
58 *
59 * Returns:
60 *	number of bytes retrieved (<= len),
61 *	-EPIPE, if the descriptor was not found, or
62 *	another negative errno code in case of other error.
63 */
64static int uclogic_params_get_str_desc(__u8 **pbuf, struct hid_device *hdev,
65					__u8 idx, size_t len)
66{
67	int rc;
68	struct usb_device *udev;
69	__u8 *buf = NULL;
70
71	/* Check arguments */
72	if (hdev == NULL) {
73		rc = -EINVAL;
74		goto cleanup;
75	}
76
77	udev = hid_to_usb_dev(hdev);
78
79	buf = kmalloc(len, GFP_KERNEL);
80	if (buf == NULL) {
81		rc = -ENOMEM;
82		goto cleanup;
83	}
84
85	rc = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
86				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
87				(USB_DT_STRING << 8) + idx,
88				0x0409, buf, len,
89				USB_CTRL_GET_TIMEOUT);
90	if (rc == -EPIPE) {
91		hid_dbg(hdev, "string descriptor #%hhu not found\n", idx);
92		goto cleanup;
93	} else if (rc < 0) {
94		hid_err(hdev,
95			"failed retrieving string descriptor #%hhu: %d\n",
96			idx, rc);
97		goto cleanup;
98	}
99
100	if (pbuf != NULL) {
101		*pbuf = buf;
102		buf = NULL;
103	}
104
105cleanup:
106	kfree(buf);
107	return rc;
108}
109
110/**
111 * uclogic_params_pen_cleanup - free resources used by struct
112 * uclogic_params_pen (tablet interface's pen input parameters).
113 * Can be called repeatedly.
114 *
115 * @pen:	Pen input parameters to cleanup. Cannot be NULL.
116 */
117static void uclogic_params_pen_cleanup(struct uclogic_params_pen *pen)
118{
119	kfree(pen->desc_ptr);
120	memset(pen, 0, sizeof(*pen));
121}
122
123/**
124 * uclogic_params_pen_init_v1() - initialize tablet interface pen
125 * input and retrieve its parameters from the device, using v1 protocol.
126 *
127 * @pen:	Pointer to the pen parameters to initialize (to be
128 *		cleaned up with uclogic_params_pen_cleanup()). Not modified in
129 *		case of error, or if parameters are not found. Cannot be NULL.
130 * @pfound:	Location for a flag which is set to true if the parameters
131 *		were found, and to false if not (e.g. device was
132 *		incompatible). Not modified in case of error. Cannot be NULL.
133 * @hdev:	The HID device of the tablet interface to initialize and get
134 *		parameters from. Cannot be NULL.
135 *
136 * Returns:
137 *	Zero, if successful. A negative errno code on error.
138 */
139static int uclogic_params_pen_init_v1(struct uclogic_params_pen *pen,
140				      bool *pfound,
141				      struct hid_device *hdev)
142{
143	int rc;
144	bool found = false;
145	/* Buffer for (part of) the string descriptor */
146	__u8 *buf = NULL;
147	/* Minimum descriptor length required, maximum seen so far is 18 */
148	const int len = 12;
149	s32 resolution;
150	/* Pen report descriptor template parameters */
151	s32 desc_params[UCLOGIC_RDESC_PEN_PH_ID_NUM];
152	__u8 *desc_ptr = NULL;
153
154	/* Check arguments */
155	if (pen == NULL || pfound == NULL || hdev == NULL) {
156		rc = -EINVAL;
157		goto cleanup;
158	}
159
160	/*
161	 * Read string descriptor containing pen input parameters.
162	 * The specific string descriptor and data were discovered by sniffing
163	 * the Windows driver traffic.
164	 * NOTE: This enables fully-functional tablet mode.
165	 */
166	rc = uclogic_params_get_str_desc(&buf, hdev, 100, len);
167	if (rc == -EPIPE) {
168		hid_dbg(hdev,
169			"string descriptor with pen parameters not found, assuming not compatible\n");
170		goto finish;
171	} else if (rc < 0) {
172		hid_err(hdev, "failed retrieving pen parameters: %d\n", rc);
173		goto cleanup;
174	} else if (rc != len) {
175		hid_dbg(hdev,
176			"string descriptor with pen parameters has invalid length (got %d, expected %d), assuming not compatible\n",
177			rc, len);
178		goto finish;
179	}
180
181	/*
182	 * Fill report descriptor parameters from the string descriptor
183	 */
184	desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] =
185		get_unaligned_le16(buf + 2);
186	desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] =
187		get_unaligned_le16(buf + 4);
188	desc_params[UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM] =
189		get_unaligned_le16(buf + 8);
190	resolution = get_unaligned_le16(buf + 10);
191	if (resolution == 0) {
192		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] = 0;
193		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] = 0;
194	} else {
195		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] =
196			desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] * 1000 /
197			resolution;
198		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] =
199			desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] * 1000 /
200			resolution;
201	}
202	kfree(buf);
203	buf = NULL;
204
205	/*
206	 * Generate pen report descriptor
207	 */
208	desc_ptr = uclogic_rdesc_template_apply(
209				uclogic_rdesc_pen_v1_template_arr,
210				uclogic_rdesc_pen_v1_template_size,
211				desc_params, ARRAY_SIZE(desc_params));
212	if (desc_ptr == NULL) {
213		rc = -ENOMEM;
214		goto cleanup;
215	}
216
217	/*
218	 * Fill-in the parameters
219	 */
220	memset(pen, 0, sizeof(*pen));
221	pen->desc_ptr = desc_ptr;
222	desc_ptr = NULL;
223	pen->desc_size = uclogic_rdesc_pen_v1_template_size;
224	pen->id = UCLOGIC_RDESC_PEN_V1_ID;
225	pen->inrange = UCLOGIC_PARAMS_PEN_INRANGE_INVERTED;
226	found = true;
227finish:
228	*pfound = found;
229	rc = 0;
230cleanup:
231	kfree(desc_ptr);
232	kfree(buf);
233	return rc;
234}
235
236/**
237 * uclogic_params_get_le24() - get a 24-bit little-endian number from a
238 * buffer.
239 *
240 * @p:	The pointer to the number buffer.
241 *
242 * Returns:
243 *	The retrieved number
244 */
245static s32 uclogic_params_get_le24(const void *p)
246{
247	const __u8 *b = p;
248	return b[0] | (b[1] << 8UL) | (b[2] << 16UL);
249}
250
251/**
252 * uclogic_params_pen_init_v2() - initialize tablet interface pen
253 * input and retrieve its parameters from the device, using v2 protocol.
254 *
255 * @pen:	Pointer to the pen parameters to initialize (to be
256 *		cleaned up with uclogic_params_pen_cleanup()). Not modified in
257 *		case of error, or if parameters are not found. Cannot be NULL.
258 * @pfound:	Location for a flag which is set to true if the parameters
259 *		were found, and to false if not (e.g. device was
260 *		incompatible). Not modified in case of error. Cannot be NULL.
261 * @hdev:	The HID device of the tablet interface to initialize and get
262 *		parameters from. Cannot be NULL.
263 *
264 * Returns:
265 *	Zero, if successful. A negative errno code on error.
266 */
267static int uclogic_params_pen_init_v2(struct uclogic_params_pen *pen,
268					bool *pfound,
269					struct hid_device *hdev)
270{
271	int rc;
272	bool found = false;
273	/* Buffer for (part of) the string descriptor */
274	__u8 *buf = NULL;
275	/* Descriptor length required */
276	const int len = 18;
277	s32 resolution;
278	/* Pen report descriptor template parameters */
279	s32 desc_params[UCLOGIC_RDESC_PEN_PH_ID_NUM];
280	__u8 *desc_ptr = NULL;
281
282	/* Check arguments */
283	if (pen == NULL || pfound == NULL || hdev == NULL) {
284		rc = -EINVAL;
285		goto cleanup;
286	}
287
288	/*
289	 * Read string descriptor containing pen input parameters.
290	 * The specific string descriptor and data were discovered by sniffing
291	 * the Windows driver traffic.
292	 * NOTE: This enables fully-functional tablet mode.
293	 */
294	rc = uclogic_params_get_str_desc(&buf, hdev, 200, len);
295	if (rc == -EPIPE) {
296		hid_dbg(hdev,
297			"string descriptor with pen parameters not found, assuming not compatible\n");
298		goto finish;
299	} else if (rc < 0) {
300		hid_err(hdev, "failed retrieving pen parameters: %d\n", rc);
301		goto cleanup;
302	} else if (rc != len) {
303		hid_dbg(hdev,
304			"string descriptor with pen parameters has invalid length (got %d, expected %d), assuming not compatible\n",
305			rc, len);
306		goto finish;
307	} else {
308		size_t i;
309		/*
310		 * Check it's not just a catch-all UTF-16LE-encoded ASCII
311		 * string (such as the model name) some tablets put into all
312		 * unknown string descriptors.
313		 */
314		for (i = 2;
315		     i < len &&
316			(buf[i] >= 0x20 && buf[i] < 0x7f && buf[i + 1] == 0);
317		     i += 2);
318		if (i >= len) {
319			hid_dbg(hdev,
320				"string descriptor with pen parameters seems to contain only text, assuming not compatible\n");
321			goto finish;
322		}
323	}
324
325	/*
326	 * Fill report descriptor parameters from the string descriptor
327	 */
328	desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] =
329		uclogic_params_get_le24(buf + 2);
330	desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] =
331		uclogic_params_get_le24(buf + 5);
332	desc_params[UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM] =
333		get_unaligned_le16(buf + 8);
334	resolution = get_unaligned_le16(buf + 10);
335	if (resolution == 0) {
336		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] = 0;
337		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] = 0;
338	} else {
339		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] =
340			desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] * 1000 /
341			resolution;
342		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] =
343			desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] * 1000 /
344			resolution;
345	}
346	kfree(buf);
347	buf = NULL;
348
349	/*
350	 * Generate pen report descriptor
351	 */
352	desc_ptr = uclogic_rdesc_template_apply(
353				uclogic_rdesc_pen_v2_template_arr,
354				uclogic_rdesc_pen_v2_template_size,
355				desc_params, ARRAY_SIZE(desc_params));
356	if (desc_ptr == NULL) {
357		rc = -ENOMEM;
358		goto cleanup;
359	}
360
361	/*
362	 * Fill-in the parameters
363	 */
364	memset(pen, 0, sizeof(*pen));
365	pen->desc_ptr = desc_ptr;
366	desc_ptr = NULL;
367	pen->desc_size = uclogic_rdesc_pen_v2_template_size;
368	pen->id = UCLOGIC_RDESC_PEN_V2_ID;
369	pen->inrange = UCLOGIC_PARAMS_PEN_INRANGE_NONE;
370	pen->fragmented_hires = true;
371	found = true;
372finish:
373	*pfound = found;
374	rc = 0;
375cleanup:
376	kfree(desc_ptr);
377	kfree(buf);
378	return rc;
379}
380
381/**
382 * uclogic_params_frame_cleanup - free resources used by struct
383 * uclogic_params_frame (tablet interface's frame controls input parameters).
384 * Can be called repeatedly.
385 *
386 * @frame:	Frame controls input parameters to cleanup. Cannot be NULL.
387 */
388static void uclogic_params_frame_cleanup(struct uclogic_params_frame *frame)
389{
390	kfree(frame->desc_ptr);
391	memset(frame, 0, sizeof(*frame));
392}
393
394/**
395 * uclogic_params_frame_init_with_desc() - initialize tablet's frame control
396 * parameters with a static report descriptor.
397 *
398 * @frame:	Pointer to the frame parameters to initialize (to be cleaned
399 *		up with uclogic_params_frame_cleanup()). Not modified in case
400 *		of error. Cannot be NULL.
401 * @desc_ptr:	Report descriptor pointer. Can be NULL, if desc_size is zero.
402 * @desc_size:	Report descriptor size.
403 * @id:		Report ID used for frame reports, if they should be tweaked,
404 *		zero if not.
405 *
406 * Returns:
407 *	Zero, if successful. A negative errno code on error.
408 */
409static int uclogic_params_frame_init_with_desc(
410					struct uclogic_params_frame *frame,
411					const __u8 *desc_ptr,
412					size_t desc_size,
413					unsigned int id)
414{
415	__u8 *copy_desc_ptr;
416
417	if (frame == NULL || (desc_ptr == NULL && desc_size != 0))
418		return -EINVAL;
419
420	copy_desc_ptr = kmemdup(desc_ptr, desc_size, GFP_KERNEL);
421	if (copy_desc_ptr == NULL)
422		return -ENOMEM;
423
424	memset(frame, 0, sizeof(*frame));
425	frame->desc_ptr = copy_desc_ptr;
426	frame->desc_size = desc_size;
427	frame->id = id;
428	return 0;
429}
430
431/**
432 * uclogic_params_frame_init_v1_buttonpad() - initialize abstract buttonpad
433 * on a v1 tablet interface.
434 *
435 * @frame:	Pointer to the frame parameters to initialize (to be cleaned
436 *		up with uclogic_params_frame_cleanup()). Not modified in case
437 *		of error, or if parameters are not found. Cannot be NULL.
438 * @pfound:	Location for a flag which is set to true if the parameters
439 *		were found, and to false if not (e.g. device was
440 *		incompatible). Not modified in case of error. Cannot be NULL.
441 * @hdev:	The HID device of the tablet interface to initialize and get
442 *		parameters from. Cannot be NULL.
443 *
444 * Returns:
445 *	Zero, if successful. A negative errno code on error.
446 */
447static int uclogic_params_frame_init_v1_buttonpad(
448					struct uclogic_params_frame *frame,
449					bool *pfound,
450					struct hid_device *hdev)
451{
452	int rc;
453	bool found = false;
454	struct usb_device *usb_dev;
455	char *str_buf = NULL;
456	const size_t str_len = 16;
457
458	/* Check arguments */
459	if (frame == NULL || pfound == NULL || hdev == NULL) {
460		rc = -EINVAL;
461		goto cleanup;
462	}
463
464	usb_dev = hid_to_usb_dev(hdev);
465
466	/*
467	 * Enable generic button mode
468	 */
469	str_buf = kzalloc(str_len, GFP_KERNEL);
470	if (str_buf == NULL) {
471		rc = -ENOMEM;
472		goto cleanup;
473	}
474
475	rc = usb_string(usb_dev, 123, str_buf, str_len);
476	if (rc == -EPIPE) {
477		hid_dbg(hdev,
478			"generic button -enabling string descriptor not found\n");
479	} else if (rc < 0) {
480		goto cleanup;
481	} else if (strncmp(str_buf, "HK On", rc) != 0) {
482		hid_dbg(hdev,
483			"invalid response to enabling generic buttons: \"%s\"\n",
484			str_buf);
485	} else {
486		hid_dbg(hdev, "generic buttons enabled\n");
487		rc = uclogic_params_frame_init_with_desc(
488				frame,
489				uclogic_rdesc_buttonpad_v1_arr,
490				uclogic_rdesc_buttonpad_v1_size,
491				UCLOGIC_RDESC_BUTTONPAD_V1_ID);
492		if (rc != 0)
493			goto cleanup;
494		found = true;
495	}
496
497	*pfound = found;
498	rc = 0;
499cleanup:
500	kfree(str_buf);
501	return rc;
502}
503
504/**
505 * uclogic_params_cleanup - free resources used by struct uclogic_params
506 * (tablet interface's parameters).
507 * Can be called repeatedly.
508 *
509 * @params:	Input parameters to cleanup. Cannot be NULL.
510 */
511void uclogic_params_cleanup(struct uclogic_params *params)
512{
513	if (!params->invalid) {
514		kfree(params->desc_ptr);
515		if (!params->pen_unused)
516			uclogic_params_pen_cleanup(&params->pen);
517		uclogic_params_frame_cleanup(&params->frame);
518		memset(params, 0, sizeof(*params));
519	}
520}
521
522/**
523 * Get a replacement report descriptor for a tablet's interface.
524 *
525 * @params:	The parameters of a tablet interface to get report
526 *		descriptor for. Cannot be NULL.
527 * @pdesc:	Location for the resulting, kmalloc-allocated report
528 *		descriptor pointer, or for NULL, if there's no replacement
529 *		report descriptor. Not modified in case of error. Cannot be
530 *		NULL.
531 * @psize:	Location for the resulting report descriptor size, not set if
532 *		there's no replacement report descriptor. Not modified in case
533 *		of error. Cannot be NULL.
534 *
535 * Returns:
536 *	Zero, if successful.
537 *	-EINVAL, if invalid arguments are supplied.
538 *	-ENOMEM, if failed to allocate memory.
539 */
540int uclogic_params_get_desc(const struct uclogic_params *params,
541				__u8 **pdesc,
542				unsigned int *psize)
543{
544	bool common_present;
545	bool pen_present;
546	bool frame_present;
547	unsigned int size;
548	__u8 *desc = NULL;
549
550	/* Check arguments */
551	if (params == NULL || pdesc == NULL || psize == NULL)
552		return -EINVAL;
553
554	size = 0;
555
556	common_present = (params->desc_ptr != NULL);
557	pen_present = (!params->pen_unused && params->pen.desc_ptr != NULL);
558	frame_present = (params->frame.desc_ptr != NULL);
559
560	if (common_present)
561		size += params->desc_size;
562	if (pen_present)
563		size += params->pen.desc_size;
564	if (frame_present)
565		size += params->frame.desc_size;
566
567	if (common_present || pen_present || frame_present) {
568		__u8 *p;
569
570		desc = kmalloc(size, GFP_KERNEL);
571		if (desc == NULL)
572			return -ENOMEM;
573		p = desc;
574
575		if (common_present) {
576			memcpy(p, params->desc_ptr,
577				params->desc_size);
578			p += params->desc_size;
579		}
580		if (pen_present) {
581			memcpy(p, params->pen.desc_ptr,
582				params->pen.desc_size);
583			p += params->pen.desc_size;
584		}
585		if (frame_present) {
586			memcpy(p, params->frame.desc_ptr,
587				params->frame.desc_size);
588			p += params->frame.desc_size;
589		}
590
591		WARN_ON(p != desc + size);
592
593		*psize = size;
594	}
595
596	*pdesc = desc;
597	return 0;
598}
599
600/**
601 * uclogic_params_init_invalid() - initialize tablet interface parameters,
602 * specifying the interface is invalid.
603 *
604 * @params:		Parameters to initialize (to be cleaned with
605 *			uclogic_params_cleanup()). Cannot be NULL.
606 */
607static void uclogic_params_init_invalid(struct uclogic_params *params)
608{
609	params->invalid = true;
610}
611
612/**
613 * uclogic_params_init_with_opt_desc() - initialize tablet interface
614 * parameters with an optional replacement report descriptor. Only modify
615 * report descriptor, if the original report descriptor matches the expected
616 * size.
617 *
618 * @params:		Parameters to initialize (to be cleaned with
619 *			uclogic_params_cleanup()). Not modified in case of
620 *			error. Cannot be NULL.
621 * @hdev:		The HID device of the tablet interface create the
622 *			parameters for. Cannot be NULL.
623 * @orig_desc_size:	Expected size of the original report descriptor to
624 *			be replaced.
625 * @desc_ptr:		Pointer to the replacement report descriptor.
626 *			Can be NULL, if desc_size is zero.
627 * @desc_size:		Size of the replacement report descriptor.
628 *
629 * Returns:
630 *	Zero, if successful. -EINVAL if an invalid argument was passed.
631 *	-ENOMEM, if failed to allocate memory.
632 */
633static int uclogic_params_init_with_opt_desc(struct uclogic_params *params,
634					     struct hid_device *hdev,
635					     unsigned int orig_desc_size,
636					     __u8 *desc_ptr,
637					     unsigned int desc_size)
638{
639	__u8 *desc_copy_ptr = NULL;
640	unsigned int desc_copy_size;
641	int rc;
642
643	/* Check arguments */
644	if (params == NULL || hdev == NULL ||
645	    (desc_ptr == NULL && desc_size != 0)) {
646		rc = -EINVAL;
647		goto cleanup;
648	}
649
650	/* Replace report descriptor, if it matches */
651	if (hdev->dev_rsize == orig_desc_size) {
652		hid_dbg(hdev,
653			"device report descriptor matches the expected size, replacing\n");
654		desc_copy_ptr = kmemdup(desc_ptr, desc_size, GFP_KERNEL);
655		if (desc_copy_ptr == NULL) {
656			rc = -ENOMEM;
657			goto cleanup;
658		}
659		desc_copy_size = desc_size;
660	} else {
661		hid_dbg(hdev,
662			"device report descriptor doesn't match the expected size (%u != %u), preserving\n",
663			hdev->dev_rsize, orig_desc_size);
664		desc_copy_ptr = NULL;
665		desc_copy_size = 0;
666	}
667
668	/* Output parameters */
669	memset(params, 0, sizeof(*params));
670	params->desc_ptr = desc_copy_ptr;
671	desc_copy_ptr = NULL;
672	params->desc_size = desc_copy_size;
673
674	rc = 0;
675cleanup:
676	kfree(desc_copy_ptr);
677	return rc;
678}
679
680/**
681 * uclogic_params_init_with_pen_unused() - initialize tablet interface
682 * parameters preserving original reports and generic HID processing, but
683 * disabling pen usage.
684 *
685 * @params:		Parameters to initialize (to be cleaned with
686 *			uclogic_params_cleanup()). Not modified in case of
687 *			error. Cannot be NULL.
688 */
689static void uclogic_params_init_with_pen_unused(struct uclogic_params *params)
690{
691	memset(params, 0, sizeof(*params));
692	params->pen_unused = true;
693}
694
695/**
696 * uclogic_params_init() - initialize a Huion tablet interface and discover
697 * its parameters.
698 *
699 * @params:	Parameters to fill in (to be cleaned with
700 *		uclogic_params_cleanup()). Not modified in case of error.
701 *		Cannot be NULL.
702 * @hdev:	The HID device of the tablet interface to initialize and get
703 *		parameters from. Cannot be NULL.
704 *
705 * Returns:
706 *	Zero, if successful. A negative errno code on error.
707 */
708static int uclogic_params_huion_init(struct uclogic_params *params,
709				     struct hid_device *hdev)
710{
711	int rc;
712	struct usb_device *udev;
713	struct usb_interface *iface;
714	__u8 bInterfaceNumber;
715	bool found;
716	/* The resulting parameters (noop) */
717	struct uclogic_params p = {0, };
718	static const char transition_ver[] = "HUION_T153_160607";
719	char *ver_ptr = NULL;
720	const size_t ver_len = sizeof(transition_ver) + 1;
721
722	/* Check arguments */
723	if (params == NULL || hdev == NULL) {
724		rc = -EINVAL;
725		goto cleanup;
726	}
727
728	udev = hid_to_usb_dev(hdev);
729	iface = to_usb_interface(hdev->dev.parent);
730	bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
731
732	/* If it's not a pen interface */
733	if (bInterfaceNumber != 0) {
734		/* TODO: Consider marking the interface invalid */
735		uclogic_params_init_with_pen_unused(&p);
736		goto output;
737	}
738
739	/* Try to get firmware version */
740	ver_ptr = kzalloc(ver_len, GFP_KERNEL);
741	if (ver_ptr == NULL) {
742		rc = -ENOMEM;
743		goto cleanup;
744	}
745	rc = usb_string(udev, 201, ver_ptr, ver_len);
746	if (rc == -EPIPE) {
747		*ver_ptr = '\0';
748	} else if (rc < 0) {
749		hid_err(hdev,
750			"failed retrieving Huion firmware version: %d\n", rc);
751		goto cleanup;
752	}
753
754	/* If this is a transition firmware */
755	if (strcmp(ver_ptr, transition_ver) == 0) {
756		hid_dbg(hdev,
757			"transition firmware detected, not probing pen v2 parameters\n");
758	} else {
759		/* Try to probe v2 pen parameters */
760		rc = uclogic_params_pen_init_v2(&p.pen, &found, hdev);
761		if (rc != 0) {
762			hid_err(hdev,
763				"failed probing pen v2 parameters: %d\n", rc);
764			goto cleanup;
765		} else if (found) {
766			hid_dbg(hdev, "pen v2 parameters found\n");
767			/* Create v2 buttonpad parameters */
768			rc = uclogic_params_frame_init_with_desc(
769					&p.frame,
770					uclogic_rdesc_buttonpad_v2_arr,
771					uclogic_rdesc_buttonpad_v2_size,
772					UCLOGIC_RDESC_BUTTONPAD_V2_ID);
773			if (rc != 0) {
774				hid_err(hdev,
775					"failed creating v2 buttonpad parameters: %d\n",
776					rc);
777				goto cleanup;
778			}
779			/* Set bitmask marking frame reports in pen reports */
780			p.pen_frame_flag = 0x20;
781			goto output;
782		}
783		hid_dbg(hdev, "pen v2 parameters not found\n");
784	}
785
786	/* Try to probe v1 pen parameters */
787	rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
788	if (rc != 0) {
789		hid_err(hdev,
790			"failed probing pen v1 parameters: %d\n", rc);
791		goto cleanup;
792	} else if (found) {
793		hid_dbg(hdev, "pen v1 parameters found\n");
794		/* Try to probe v1 buttonpad */
795		rc = uclogic_params_frame_init_v1_buttonpad(
796						&p.frame,
797						&found, hdev);
798		if (rc != 0) {
799			hid_err(hdev, "v1 buttonpad probing failed: %d\n", rc);
800			goto cleanup;
801		}
802		hid_dbg(hdev, "buttonpad v1 parameters%s found\n",
803			(found ? "" : " not"));
804		if (found) {
805			/* Set bitmask marking frame reports */
806			p.pen_frame_flag = 0x20;
807		}
808		goto output;
809	}
810	hid_dbg(hdev, "pen v1 parameters not found\n");
811
812	uclogic_params_init_invalid(&p);
813
814output:
815	/* Output parameters */
816	memcpy(params, &p, sizeof(*params));
817	memset(&p, 0, sizeof(p));
818	rc = 0;
819cleanup:
820	kfree(ver_ptr);
821	uclogic_params_cleanup(&p);
822	return rc;
823}
824
825/**
826 * uclogic_params_init() - initialize a tablet interface and discover its
827 * parameters.
828 *
829 * @params:	Parameters to fill in (to be cleaned with
830 *		uclogic_params_cleanup()). Not modified in case of error.
831 *		Cannot be NULL.
832 * @hdev:	The HID device of the tablet interface to initialize and get
833 *		parameters from. Cannot be NULL. Must be using the USB low-level
834 *		driver, i.e. be an actual USB tablet.
835 *
836 * Returns:
837 *	Zero, if successful. A negative errno code on error.
838 */
839int uclogic_params_init(struct uclogic_params *params,
840			struct hid_device *hdev)
841{
842	int rc;
843	struct usb_device *udev;
844	__u8  bNumInterfaces;
845	struct usb_interface *iface;
846	__u8 bInterfaceNumber;
847	bool found;
848	/* The resulting parameters (noop) */
849	struct uclogic_params p = {0, };
850
851	/* Check arguments */
852	if (params == NULL || hdev == NULL || !hid_is_usb(hdev)) {
853		rc = -EINVAL;
854		goto cleanup;
855	}
856
857	udev = hid_to_usb_dev(hdev);
858	bNumInterfaces = udev->config->desc.bNumInterfaces;
859	iface = to_usb_interface(hdev->dev.parent);
860	bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
861
862	/*
863	 * Set replacement report descriptor if the original matches the
864	 * specified size. Otherwise keep interface unchanged.
865	 */
866#define WITH_OPT_DESC(_orig_desc_token, _new_desc_token) \
867	uclogic_params_init_with_opt_desc(                  \
868		&p, hdev,                                   \
869		UCLOGIC_RDESC_##_orig_desc_token##_SIZE,    \
870		uclogic_rdesc_##_new_desc_token##_arr,      \
871		uclogic_rdesc_##_new_desc_token##_size)
872
873#define VID_PID(_vid, _pid) \
874	(((__u32)(_vid) << 16) | ((__u32)(_pid) & U16_MAX))
875
876	/*
877	 * Handle specific interfaces for specific tablets.
878	 *
879	 * Observe the following logic:
880	 *
881	 * If the interface is recognized as producing certain useful input:
882	 *	Mark interface as valid.
883	 *	Output interface parameters.
884	 * Else, if the interface is recognized as *not* producing any useful
885	 * input:
886	 *	Mark interface as invalid.
887	 * Else:
888	 *	Mark interface as valid.
889	 *	Output noop parameters.
890	 *
891	 * Rule of thumb: it is better to disable a broken interface than let
892	 *		  it spew garbage input.
893	 */
894
895	switch (VID_PID(hdev->vendor, hdev->product)) {
896	case VID_PID(USB_VENDOR_ID_UCLOGIC,
897		     USB_DEVICE_ID_UCLOGIC_TABLET_PF1209):
898		rc = WITH_OPT_DESC(PF1209_ORIG, pf1209_fixed);
899		if (rc != 0)
900			goto cleanup;
901		break;
902	case VID_PID(USB_VENDOR_ID_UCLOGIC,
903		     USB_DEVICE_ID_UCLOGIC_TABLET_WP4030U):
904		rc = WITH_OPT_DESC(WPXXXXU_ORIG, wp4030u_fixed);
905		if (rc != 0)
906			goto cleanup;
907		break;
908	case VID_PID(USB_VENDOR_ID_UCLOGIC,
909		     USB_DEVICE_ID_UCLOGIC_TABLET_WP5540U):
910		if (hdev->dev_rsize == UCLOGIC_RDESC_WP5540U_V2_ORIG_SIZE) {
911			if (bInterfaceNumber == 0) {
912				/* Try to probe v1 pen parameters */
913				rc = uclogic_params_pen_init_v1(&p.pen,
914								&found, hdev);
915				if (rc != 0) {
916					hid_err(hdev,
917						"pen probing failed: %d\n",
918						rc);
919					goto cleanup;
920				}
921				if (!found) {
922					hid_warn(hdev,
923						 "pen parameters not found");
924				}
925			} else {
926				uclogic_params_init_invalid(&p);
927			}
928		} else {
929			rc = WITH_OPT_DESC(WPXXXXU_ORIG, wp5540u_fixed);
930			if (rc != 0)
931				goto cleanup;
932		}
933		break;
934	case VID_PID(USB_VENDOR_ID_UCLOGIC,
935		     USB_DEVICE_ID_UCLOGIC_TABLET_WP8060U):
936		rc = WITH_OPT_DESC(WPXXXXU_ORIG, wp8060u_fixed);
937		if (rc != 0)
938			goto cleanup;
939		break;
940	case VID_PID(USB_VENDOR_ID_UCLOGIC,
941		     USB_DEVICE_ID_UCLOGIC_TABLET_WP1062):
942		rc = WITH_OPT_DESC(WP1062_ORIG, wp1062_fixed);
943		if (rc != 0)
944			goto cleanup;
945		break;
946	case VID_PID(USB_VENDOR_ID_UCLOGIC,
947		     USB_DEVICE_ID_UCLOGIC_WIRELESS_TABLET_TWHL850):
948		switch (bInterfaceNumber) {
949		case 0:
950			rc = WITH_OPT_DESC(TWHL850_ORIG0, twhl850_fixed0);
951			if (rc != 0)
952				goto cleanup;
953			break;
954		case 1:
955			rc = WITH_OPT_DESC(TWHL850_ORIG1, twhl850_fixed1);
956			if (rc != 0)
957				goto cleanup;
958			break;
959		case 2:
960			rc = WITH_OPT_DESC(TWHL850_ORIG2, twhl850_fixed2);
961			if (rc != 0)
962				goto cleanup;
963			break;
964		}
965		break;
966	case VID_PID(USB_VENDOR_ID_UCLOGIC,
967		     USB_DEVICE_ID_UCLOGIC_TABLET_TWHA60):
968		/*
969		 * If it is not a three-interface version, which is known to
970		 * respond to initialization.
971		 */
972		if (bNumInterfaces != 3) {
973			switch (bInterfaceNumber) {
974			case 0:
975				rc = WITH_OPT_DESC(TWHA60_ORIG0,
976							twha60_fixed0);
977				if (rc != 0)
978					goto cleanup;
979				break;
980			case 1:
981				rc = WITH_OPT_DESC(TWHA60_ORIG1,
982							twha60_fixed1);
983				if (rc != 0)
984					goto cleanup;
985				break;
986			}
987			break;
988		}
989		fallthrough;
990	case VID_PID(USB_VENDOR_ID_HUION,
991		     USB_DEVICE_ID_HUION_TABLET):
992	case VID_PID(USB_VENDOR_ID_HUION,
993		     USB_DEVICE_ID_HUION_HS64):
994	case VID_PID(USB_VENDOR_ID_UCLOGIC,
995		     USB_DEVICE_ID_HUION_TABLET):
996	case VID_PID(USB_VENDOR_ID_UCLOGIC,
997		     USB_DEVICE_ID_YIYNOVA_TABLET):
998	case VID_PID(USB_VENDOR_ID_UCLOGIC,
999		     USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_81):
1000	case VID_PID(USB_VENDOR_ID_UCLOGIC,
1001		     USB_DEVICE_ID_UCLOGIC_DRAWIMAGE_G3):
1002	case VID_PID(USB_VENDOR_ID_UCLOGIC,
1003		     USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_45):
1004	case VID_PID(USB_VENDOR_ID_UCLOGIC,
1005		     USB_DEVICE_ID_UCLOGIC_UGEE_TABLET_47):
1006		rc = uclogic_params_huion_init(&p, hdev);
1007		if (rc != 0)
1008			goto cleanup;
1009		break;
1010	case VID_PID(USB_VENDOR_ID_UGTIZER,
1011		     USB_DEVICE_ID_UGTIZER_TABLET_GP0610):
1012	case VID_PID(USB_VENDOR_ID_UGTIZER,
1013		     USB_DEVICE_ID_UGTIZER_TABLET_GT5040):
1014	case VID_PID(USB_VENDOR_ID_UGEE,
1015		     USB_DEVICE_ID_UGEE_XPPEN_TABLET_G540):
1016	case VID_PID(USB_VENDOR_ID_UGEE,
1017		     USB_DEVICE_ID_UGEE_XPPEN_TABLET_G640):
1018	case VID_PID(USB_VENDOR_ID_UGEE,
1019		     USB_DEVICE_ID_UGEE_TABLET_RAINBOW_CV720):
1020		/* If this is the pen interface */
1021		if (bInterfaceNumber == 1) {
1022			/* Probe v1 pen parameters */
1023			rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
1024			if (rc != 0) {
1025				hid_err(hdev, "pen probing failed: %d\n", rc);
1026				goto cleanup;
1027			}
1028			if (!found) {
1029				hid_warn(hdev, "pen parameters not found");
1030				uclogic_params_init_invalid(&p);
1031			}
1032		} else {
1033			/* TODO: Consider marking the interface invalid */
1034			uclogic_params_init_with_pen_unused(&p);
1035		}
1036		break;
1037	case VID_PID(USB_VENDOR_ID_UGEE,
1038		     USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO01):
1039		/* If this is the pen and frame interface */
1040		if (bInterfaceNumber == 1) {
1041			/* Probe v1 pen parameters */
1042			rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
1043			if (rc != 0) {
1044				hid_err(hdev, "pen probing failed: %d\n", rc);
1045				goto cleanup;
1046			}
1047			/* Initialize frame parameters */
1048			rc = uclogic_params_frame_init_with_desc(
1049				&p.frame,
1050				uclogic_rdesc_xppen_deco01_frame_arr,
1051				uclogic_rdesc_xppen_deco01_frame_size,
1052				0);
1053			if (rc != 0)
1054				goto cleanup;
1055		} else {
1056			/* TODO: Consider marking the interface invalid */
1057			uclogic_params_init_with_pen_unused(&p);
1058		}
1059		break;
1060	case VID_PID(USB_VENDOR_ID_UGEE,
1061		     USB_DEVICE_ID_UGEE_TABLET_G5):
1062		/* Ignore non-pen interfaces */
1063		if (bInterfaceNumber != 1) {
1064			uclogic_params_init_invalid(&p);
1065			break;
1066		}
1067
1068		rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
1069		if (rc != 0) {
1070			hid_err(hdev, "pen probing failed: %d\n", rc);
1071			goto cleanup;
1072		} else if (found) {
1073			rc = uclogic_params_frame_init_with_desc(
1074				&p.frame,
1075				uclogic_rdesc_ugee_g5_frame_arr,
1076				uclogic_rdesc_ugee_g5_frame_size,
1077				UCLOGIC_RDESC_UGEE_G5_FRAME_ID);
1078			if (rc != 0) {
1079				hid_err(hdev,
1080					"failed creating buttonpad parameters: %d\n",
1081					rc);
1082				goto cleanup;
1083			}
1084			p.frame.re_lsb =
1085				UCLOGIC_RDESC_UGEE_G5_FRAME_RE_LSB;
1086			p.frame.dev_id_byte =
1087				UCLOGIC_RDESC_UGEE_G5_FRAME_DEV_ID_BYTE;
1088		} else {
1089			hid_warn(hdev, "pen parameters not found");
1090			uclogic_params_init_invalid(&p);
1091		}
1092
1093		break;
1094	case VID_PID(USB_VENDOR_ID_UGEE,
1095		     USB_DEVICE_ID_UGEE_TABLET_EX07S):
1096		/* Ignore non-pen interfaces */
1097		if (bInterfaceNumber != 1) {
1098			uclogic_params_init_invalid(&p);
1099			break;
1100		}
1101
1102		rc = uclogic_params_pen_init_v1(&p.pen, &found, hdev);
1103		if (rc != 0) {
1104			hid_err(hdev, "pen probing failed: %d\n", rc);
1105			goto cleanup;
1106		} else if (found) {
1107			rc = uclogic_params_frame_init_with_desc(
1108				&p.frame,
1109				uclogic_rdesc_ugee_ex07_buttonpad_arr,
1110				uclogic_rdesc_ugee_ex07_buttonpad_size,
1111				0);
1112			if (rc != 0) {
1113				hid_err(hdev,
1114					"failed creating buttonpad parameters: %d\n",
1115					rc);
1116				goto cleanup;
1117			}
1118		} else {
1119			hid_warn(hdev, "pen parameters not found");
1120			uclogic_params_init_invalid(&p);
1121		}
1122
1123		break;
1124	}
1125
1126#undef VID_PID
1127#undef WITH_OPT_DESC
1128
1129	/* Output parameters */
1130	memcpy(params, &p, sizeof(*params));
1131	memset(&p, 0, sizeof(p));
1132	rc = 0;
1133cleanup:
1134	uclogic_params_cleanup(&p);
1135	return rc;
1136}
1137