1 /*
2  * Copyright 2018 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Authors: AMD
23  *
24  */
25 
26 #include "mod_info_packet.h"
27 #include "core_types.h"
28 #include "dc_types.h"
29 #include "mod_shared.h"
30 #include "mod_freesync.h"
31 #include "dc.h"
32 
33 enum vsc_packet_revision {
34 	vsc_packet_undefined = 0,
35 	//01h = VSC SDP supports only 3D stereo.
36 	vsc_packet_rev1 = 1,
37 	//02h = 3D stereo + PSR.
38 	vsc_packet_rev2 = 2,
39 	//03h = 3D stereo + PSR2.
40 	vsc_packet_rev3 = 3,
41 	//04h = 3D stereo + PSR/PSR2 + Y-coordinate.
42 	vsc_packet_rev4 = 4,
43 	//05h = 3D stereo + PSR/PSR2 + Y-coordinate + Pixel Encoding/Colorimetry Format
44 	vsc_packet_rev5 = 5,
45 };
46 
47 #define HDMI_INFOFRAME_TYPE_VENDOR 0x81
48 #define HF_VSIF_VERSION 1
49 
50 // VTEM Byte Offset
51 #define VTEM_PB0		0
52 #define VTEM_PB1		1
53 #define VTEM_PB2		2
54 #define VTEM_PB3		3
55 #define VTEM_PB4		4
56 #define VTEM_PB5		5
57 #define VTEM_PB6		6
58 
59 #define VTEM_MD0		7
60 #define VTEM_MD1		8
61 #define VTEM_MD2		9
62 #define VTEM_MD3		10
63 
64 
65 // VTEM Byte Masks
66 //PB0
67 #define MASK_VTEM_PB0__RESERVED0  0x01
68 #define MASK_VTEM_PB0__SYNC       0x02
69 #define MASK_VTEM_PB0__VFR        0x04
70 #define MASK_VTEM_PB0__AFR        0x08
71 #define MASK_VTEM_PB0__DS_TYPE    0x30
72 	//0: Periodic pseudo-static EM Data Set
73 	//1: Periodic dynamic EM Data Set
74 	//2: Unique EM Data Set
75 	//3: Reserved
76 #define MASK_VTEM_PB0__END        0x40
77 #define MASK_VTEM_PB0__NEW        0x80
78 
79 //PB1
80 #define MASK_VTEM_PB1__RESERVED1 0xFF
81 
82 //PB2
83 #define MASK_VTEM_PB2__ORGANIZATION_ID 0xFF
84 	//0: This is a Vendor Specific EM Data Set
85 	//1: This EM Data Set is defined by This Specification (HDMI 2.1 r102.clean)
86 	//2: This EM Data Set is defined by CTA-861-G
87 	//3: This EM Data Set is defined by VESA
88 //PB3
89 #define MASK_VTEM_PB3__DATA_SET_TAG_MSB    0xFF
90 //PB4
91 #define MASK_VTEM_PB4__DATA_SET_TAG_LSB    0xFF
92 //PB5
93 #define MASK_VTEM_PB5__DATA_SET_LENGTH_MSB 0xFF
94 //PB6
95 #define MASK_VTEM_PB6__DATA_SET_LENGTH_LSB 0xFF
96 
97 
98 
99 //PB7-27 (20 bytes):
100 //PB7 = MD0
101 #define MASK_VTEM_MD0__VRR_EN         0x01
102 #define MASK_VTEM_MD0__M_CONST        0x02
103 #define MASK_VTEM_MD0__QMS_EN         0x04
104 #define MASK_VTEM_MD0__RESERVED2      0x08
105 #define MASK_VTEM_MD0__FVA_FACTOR_M1  0xF0
106 
107 //MD1
108 #define MASK_VTEM_MD1__BASE_VFRONT    0xFF
109 
110 //MD2
111 #define MASK_VTEM_MD2__BASE_REFRESH_RATE_98  0x03
112 #define MASK_VTEM_MD2__RB                    0x04
113 #define MASK_VTEM_MD2__NEXT_TFR              0xF8
114 
115 //MD3
116 #define MASK_VTEM_MD3__BASE_REFRESH_RATE_07  0xFF
117 
118 enum ColorimetryRGBDP {
119 	ColorimetryRGB_DP_sRGB               = 0,
120 	ColorimetryRGB_DP_AdobeRGB           = 3,
121 	ColorimetryRGB_DP_P3                 = 4,
122 	ColorimetryRGB_DP_CustomColorProfile = 5,
123 	ColorimetryRGB_DP_ITU_R_BT2020RGB    = 6,
124 };
125 enum ColorimetryYCCDP {
126 	ColorimetryYCC_DP_ITU601        = 0,
127 	ColorimetryYCC_DP_ITU709        = 1,
128 	ColorimetryYCC_DP_AdobeYCC      = 5,
129 	ColorimetryYCC_DP_ITU2020YCC    = 6,
130 	ColorimetryYCC_DP_ITU2020YCbCr  = 7,
131 };
132 
mod_build_vsc_infopacket(const struct dc_stream_state * stream,struct dc_info_packet * info_packet,enum dc_color_space cs)133 void mod_build_vsc_infopacket(const struct dc_stream_state *stream,
134 		struct dc_info_packet *info_packet,
135 		enum dc_color_space cs)
136 {
137 	unsigned int vsc_packet_revision = vsc_packet_undefined;
138 	unsigned int i;
139 	unsigned int pixelEncoding = 0;
140 	unsigned int colorimetryFormat = 0;
141 	bool stereo3dSupport = false;
142 
143 	if (stream->timing.timing_3d_format != TIMING_3D_FORMAT_NONE && stream->view_format != VIEW_3D_FORMAT_NONE) {
144 		vsc_packet_revision = vsc_packet_rev1;
145 		stereo3dSupport = true;
146 	}
147 
148 	/* VSC packet set to 4 for PSR-SU, or 2 for PSR1 */
149 	if (stream->link->psr_settings.psr_version == DC_PSR_VERSION_SU_1)
150 		vsc_packet_revision = vsc_packet_rev4;
151 	else if (stream->link->psr_settings.psr_version == DC_PSR_VERSION_1)
152 		vsc_packet_revision = vsc_packet_rev2;
153 
154 	/* Update to revision 5 for extended colorimetry support */
155 	if (stream->use_vsc_sdp_for_colorimetry)
156 		vsc_packet_revision = vsc_packet_rev5;
157 
158 	/* VSC packet not needed based on the features
159 	 * supported by this DP display
160 	 */
161 	if (vsc_packet_revision == vsc_packet_undefined)
162 		return;
163 
164 	if (vsc_packet_revision == vsc_packet_rev4) {
165 		/* Secondary-data Packet ID = 0*/
166 		info_packet->hb0 = 0x00;
167 		/* 07h - Packet Type Value indicating Video
168 		 * Stream Configuration packet
169 		 */
170 		info_packet->hb1 = 0x07;
171 		/* 04h = VSC SDP supporting 3D stereo + PSR/PSR2 + Y-coordinate
172 		 * (applies to eDP v1.4 or higher).
173 		 */
174 		info_packet->hb2 = 0x04;
175 		/* 0Eh = VSC SDP supporting 3D stereo + PSR2
176 		 * (HB2 = 04h), with Y-coordinate of first scan
177 		 * line of the SU region
178 		 */
179 		info_packet->hb3 = 0x0E;
180 
181 		for (i = 0; i < 28; i++)
182 			info_packet->sb[i] = 0;
183 
184 		info_packet->valid = true;
185 	}
186 
187 	if (vsc_packet_revision == vsc_packet_rev2) {
188 		/* Secondary-data Packet ID = 0*/
189 		info_packet->hb0 = 0x00;
190 		/* 07h - Packet Type Value indicating Video
191 		 * Stream Configuration packet
192 		 */
193 		info_packet->hb1 = 0x07;
194 		/* 02h = VSC SDP supporting 3D stereo and PSR
195 		 * (applies to eDP v1.3 or higher).
196 		 */
197 		info_packet->hb2 = 0x02;
198 		/* 08h = VSC packet supporting 3D stereo + PSR
199 		 * (HB2 = 02h).
200 		 */
201 		info_packet->hb3 = 0x08;
202 
203 		for (i = 0; i < 28; i++)
204 			info_packet->sb[i] = 0;
205 
206 		info_packet->valid = true;
207 	}
208 
209 	if (vsc_packet_revision == vsc_packet_rev1) {
210 
211 		info_packet->hb0 = 0x00;	// Secondary-data Packet ID = 0
212 		info_packet->hb1 = 0x07;	// 07h = Packet Type Value indicating Video Stream Configuration packet
213 		info_packet->hb2 = 0x01;	// 01h = Revision number. VSC SDP supporting 3D stereo only
214 		info_packet->hb3 = 0x01;	// 01h = VSC SDP supporting 3D stereo only (HB2 = 01h).
215 
216 		info_packet->valid = true;
217 	}
218 
219 	if (stereo3dSupport) {
220 		/* ==============================================================================================================|
221 		 * A. STEREO 3D
222 		 * ==============================================================================================================|
223 		 * VSC Payload (1 byte) From DP1.2 spec
224 		 *
225 		 * Bits 3:0 (Stereo Interface Method Code)  |  Bits 7:4 (Stereo Interface Method Specific Parameter)
226 		 * -----------------------------------------------------------------------------------------------------
227 		 * 0 = Non Stereo Video                     |  Must be set to 0x0
228 		 * -----------------------------------------------------------------------------------------------------
229 		 * 1 = Frame/Field Sequential               |  0x0: L + R view indication based on MISC1 bit 2:1
230 		 *                                          |  0x1: Right when Stereo Signal = 1
231 		 *                                          |  0x2: Left when Stereo Signal = 1
232 		 *                                          |  (others reserved)
233 		 * -----------------------------------------------------------------------------------------------------
234 		 * 2 = Stacked Frame                        |  0x0: Left view is on top and right view on bottom
235 		 *                                          |  (others reserved)
236 		 * -----------------------------------------------------------------------------------------------------
237 		 * 3 = Pixel Interleaved                    |  0x0: horiz interleaved, right view pixels on even lines
238 		 *                                          |  0x1: horiz interleaved, right view pixels on odd lines
239 		 *                                          |  0x2: checker board, start with left view pixel
240 		 *                                          |  0x3: vertical interleaved, start with left view pixels
241 		 *                                          |  0x4: vertical interleaved, start with right view pixels
242 		 *                                          |  (others reserved)
243 		 * -----------------------------------------------------------------------------------------------------
244 		 * 4 = Side-by-side                         |  0x0: left half represents left eye view
245 		 *                                          |  0x1: left half represents right eye view
246 		 */
247 		switch (stream->timing.timing_3d_format) {
248 		case TIMING_3D_FORMAT_HW_FRAME_PACKING:
249 		case TIMING_3D_FORMAT_SW_FRAME_PACKING:
250 		case TIMING_3D_FORMAT_TOP_AND_BOTTOM:
251 		case TIMING_3D_FORMAT_TB_SW_PACKED:
252 			info_packet->sb[0] = 0x02; // Stacked Frame, Left view is on top and right view on bottom.
253 			break;
254 		case TIMING_3D_FORMAT_DP_HDMI_INBAND_FA:
255 		case TIMING_3D_FORMAT_INBAND_FA:
256 			info_packet->sb[0] = 0x01; // Frame/Field Sequential, L + R view indication based on MISC1 bit 2:1
257 			break;
258 		case TIMING_3D_FORMAT_SIDE_BY_SIDE:
259 		case TIMING_3D_FORMAT_SBS_SW_PACKED:
260 			info_packet->sb[0] = 0x04; // Side-by-side
261 			break;
262 		default:
263 			info_packet->sb[0] = 0x00; // No Stereo Video, Shall be cleared to 0x0.
264 			break;
265 		}
266 
267 	}
268 
269 	/* 05h = VSC SDP supporting 3D stereo, PSR2, and Pixel Encoding/Colorimetry Format indication.
270 	 *   Added in DP1.3, a DP Source device is allowed to indicate the pixel encoding/colorimetry
271 	 *   format to the DP Sink device with VSC SDP only when the DP Sink device supports it
272 	 *   (i.e., VSC_SDP_EXTENSION_FOR_COLORIMETRY_SUPPORTED bit in the DPRX_FEATURE_ENUMERATION_LIST
273 	 *   register (DPCD Address 02210h, bit 3) is set to 1).
274 	 *   (Requires VSC_SDP_EXTENSION_FOR_COLORIMETRY_SUPPORTED bit set to 1 in DPCD 02210h. This
275 	 *   DPCD register is exposed in the new Extended Receiver Capability field for DPCD Rev. 1.4
276 	 *   (and higher). When MISC1. bit 6. is Set to 1, a Source device uses a VSC SDP to indicate
277 	 *   the Pixel Encoding/Colorimetry Format and that a Sink device must ignore MISC1, bit 7, and
278 	 *   MISC0, bits 7:1 (MISC1, bit 7. and MISC0, bits 7:1 become "don't care").)
279 	 */
280 	if (vsc_packet_revision == vsc_packet_rev5) {
281 		/* Secondary-data Packet ID = 0 */
282 		info_packet->hb0 = 0x00;
283 		/* 07h - Packet Type Value indicating Video Stream Configuration packet */
284 		info_packet->hb1 = 0x07;
285 		/* 05h = VSC SDP supporting 3D stereo, PSR2, and Pixel Encoding/Colorimetry Format indication. */
286 		info_packet->hb2 = 0x05;
287 		/* 13h = VSC SDP supporting 3D stereo, + PSR2, + Pixel Encoding/Colorimetry Format indication (HB2 = 05h). */
288 		info_packet->hb3 = 0x13;
289 
290 		info_packet->valid = true;
291 
292 		/* Set VSC SDP fields for pixel encoding and colorimetry format from DP 1.3 specs
293 		 * Data Bytes DB 18~16
294 		 * Bits 3:0 (Colorimetry Format)        |  Bits 7:4 (Pixel Encoding)
295 		 * ----------------------------------------------------------------------------------------------------
296 		 * 0x0 = sRGB                           |  0 = RGB
297 		 * 0x1 = RGB Wide Gamut Fixed Point
298 		 * 0x2 = RGB Wide Gamut Floating Point
299 		 * 0x3 = AdobeRGB
300 		 * 0x4 = DCI-P3
301 		 * 0x5 = CustomColorProfile
302 		 * (others reserved)
303 		 * ----------------------------------------------------------------------------------------------------
304 		 * 0x0 = ITU-R BT.601                   |  1 = YCbCr444
305 		 * 0x1 = ITU-R BT.709
306 		 * 0x2 = xvYCC601
307 		 * 0x3 = xvYCC709
308 		 * 0x4 = sYCC601
309 		 * 0x5 = AdobeYCC601
310 		 * 0x6 = ITU-R BT.2020 Y'cC'bcC'rc
311 		 * 0x7 = ITU-R BT.2020 Y'C'bC'r
312 		 * (others reserved)
313 		 * ----------------------------------------------------------------------------------------------------
314 		 * 0x0 = ITU-R BT.601                   |  2 = YCbCr422
315 		 * 0x1 = ITU-R BT.709
316 		 * 0x2 = xvYCC601
317 		 * 0x3 = xvYCC709
318 		 * 0x4 = sYCC601
319 		 * 0x5 = AdobeYCC601
320 		 * 0x6 = ITU-R BT.2020 Y'cC'bcC'rc
321 		 * 0x7 = ITU-R BT.2020 Y'C'bC'r
322 		 * (others reserved)
323 		 * ----------------------------------------------------------------------------------------------------
324 		 * 0x0 = ITU-R BT.601                   |  3 = YCbCr420
325 		 * 0x1 = ITU-R BT.709
326 		 * 0x2 = xvYCC601
327 		 * 0x3 = xvYCC709
328 		 * 0x4 = sYCC601
329 		 * 0x5 = AdobeYCC601
330 		 * 0x6 = ITU-R BT.2020 Y'cC'bcC'rc
331 		 * 0x7 = ITU-R BT.2020 Y'C'bC'r
332 		 * (others reserved)
333 		 * ----------------------------------------------------------------------------------------------------
334 		 * 0x0 =DICOM Part14 Grayscale          |  4 = Yonly
335 		 * Display Function
336 		 * (others reserved)
337 		 */
338 
339 		/* Set Pixel Encoding */
340 		switch (stream->timing.pixel_encoding) {
341 		case PIXEL_ENCODING_RGB:
342 			pixelEncoding = 0x0;  /* RGB = 0h */
343 			break;
344 		case PIXEL_ENCODING_YCBCR444:
345 			pixelEncoding = 0x1;  /* YCbCr444 = 1h */
346 			break;
347 		case PIXEL_ENCODING_YCBCR422:
348 			pixelEncoding = 0x2;  /* YCbCr422 = 2h */
349 			break;
350 		case PIXEL_ENCODING_YCBCR420:
351 			pixelEncoding = 0x3;  /* YCbCr420 = 3h */
352 			break;
353 		default:
354 			pixelEncoding = 0x0;  /* default RGB = 0h */
355 			break;
356 		}
357 
358 		/* Set Colorimetry format based on pixel encoding */
359 		switch (stream->timing.pixel_encoding) {
360 		case PIXEL_ENCODING_RGB:
361 			if ((cs == COLOR_SPACE_SRGB) ||
362 					(cs == COLOR_SPACE_SRGB_LIMITED))
363 				colorimetryFormat = ColorimetryRGB_DP_sRGB;
364 			else if (cs == COLOR_SPACE_ADOBERGB)
365 				colorimetryFormat = ColorimetryRGB_DP_AdobeRGB;
366 			else if ((cs == COLOR_SPACE_2020_RGB_FULLRANGE) ||
367 					(cs == COLOR_SPACE_2020_RGB_LIMITEDRANGE))
368 				colorimetryFormat = ColorimetryRGB_DP_ITU_R_BT2020RGB;
369 			break;
370 
371 		case PIXEL_ENCODING_YCBCR444:
372 		case PIXEL_ENCODING_YCBCR422:
373 		case PIXEL_ENCODING_YCBCR420:
374 			/* Note: xvYCC probably not supported correctly here on DP since colorspace translation
375 			 * loses distinction between BT601 vs xvYCC601 in translation
376 			 */
377 			if (cs == COLOR_SPACE_YCBCR601)
378 				colorimetryFormat = ColorimetryYCC_DP_ITU601;
379 			else if (cs == COLOR_SPACE_YCBCR709)
380 				colorimetryFormat = ColorimetryYCC_DP_ITU709;
381 			else if (cs == COLOR_SPACE_ADOBERGB)
382 				colorimetryFormat = ColorimetryYCC_DP_AdobeYCC;
383 			else if (cs == COLOR_SPACE_2020_YCBCR)
384 				colorimetryFormat = ColorimetryYCC_DP_ITU2020YCbCr;
385 			break;
386 
387 		default:
388 			colorimetryFormat = ColorimetryRGB_DP_sRGB;
389 			break;
390 		}
391 
392 		info_packet->sb[16] = (pixelEncoding << 4) | colorimetryFormat;
393 
394 		/* Set color depth */
395 		switch (stream->timing.display_color_depth) {
396 		case COLOR_DEPTH_666:
397 			/* NOTE: This is actually not valid for YCbCr pixel encoding to have 6 bpc
398 			 *       as of DP1.4 spec, but value of 0 probably reserved here for potential future use.
399 			 */
400 			info_packet->sb[17] = 0;
401 			break;
402 		case COLOR_DEPTH_888:
403 			info_packet->sb[17] = 1;
404 			break;
405 		case COLOR_DEPTH_101010:
406 			info_packet->sb[17] = 2;
407 			break;
408 		case COLOR_DEPTH_121212:
409 			info_packet->sb[17] = 3;
410 			break;
411 		/*case COLOR_DEPTH_141414: -- NO SUCH FORMAT IN DP SPEC */
412 		case COLOR_DEPTH_161616:
413 			info_packet->sb[17] = 4;
414 			break;
415 		default:
416 			info_packet->sb[17] = 0;
417 			break;
418 		}
419 
420 		/* all YCbCr are always limited range */
421 		if ((cs == COLOR_SPACE_SRGB_LIMITED) ||
422 				(cs == COLOR_SPACE_2020_RGB_LIMITEDRANGE) ||
423 				(pixelEncoding != 0x0)) {
424 			info_packet->sb[17] |= 0x80; /* DB17 bit 7 set to 1 for CEA timing. */
425 		}
426 
427 		/* Content Type (Bits 2:0)
428 		 *  0 = Not defined.
429 		 *  1 = Graphics.
430 		 *  2 = Photo.
431 		 *  3 = Video.
432 		 *  4 = Game.
433 		 */
434 		info_packet->sb[18] = 0;
435 	}
436 }
437 
438 /**
439  *  mod_build_hf_vsif_infopacket - Prepare HDMI Vendor Specific info frame.
440  *                                 Follows HDMI Spec to build up Vendor Specific info frame
441  *
442  *  @stream:      contains data we may need to construct VSIF (i.e. timing_3d_format, etc.)
443  *  @info_packet: output structure where to store VSIF
444  */
mod_build_hf_vsif_infopacket(const struct dc_stream_state * stream,struct dc_info_packet * info_packet)445 void mod_build_hf_vsif_infopacket(const struct dc_stream_state *stream,
446 		struct dc_info_packet *info_packet)
447 {
448 		unsigned int length = 5;
449 		bool hdmi_vic_mode = false;
450 		uint8_t checksum = 0;
451 		uint32_t i = 0;
452 		enum dc_timing_3d_format format;
453 
454 		info_packet->valid = false;
455 		format = stream->timing.timing_3d_format;
456 		if (stream->view_format == VIEW_3D_FORMAT_NONE)
457 			format = TIMING_3D_FORMAT_NONE;
458 
459 		if (stream->timing.hdmi_vic != 0
460 				&& stream->timing.h_total >= 3840
461 				&& stream->timing.v_total >= 2160
462 				&& format == TIMING_3D_FORMAT_NONE)
463 			hdmi_vic_mode = true;
464 
465 		if ((format == TIMING_3D_FORMAT_NONE) && !hdmi_vic_mode)
466 			return;
467 
468 		info_packet->sb[1] = 0x03;
469 		info_packet->sb[2] = 0x0C;
470 		info_packet->sb[3] = 0x00;
471 
472 		if (format != TIMING_3D_FORMAT_NONE)
473 			info_packet->sb[4] = (2 << 5);
474 
475 		else if (hdmi_vic_mode)
476 			info_packet->sb[4] = (1 << 5);
477 
478 		switch (format) {
479 		case TIMING_3D_FORMAT_HW_FRAME_PACKING:
480 		case TIMING_3D_FORMAT_SW_FRAME_PACKING:
481 			info_packet->sb[5] = (0x0 << 4);
482 			break;
483 
484 		case TIMING_3D_FORMAT_SIDE_BY_SIDE:
485 		case TIMING_3D_FORMAT_SBS_SW_PACKED:
486 			info_packet->sb[5] = (0x8 << 4);
487 			length = 6;
488 			break;
489 
490 		case TIMING_3D_FORMAT_TOP_AND_BOTTOM:
491 		case TIMING_3D_FORMAT_TB_SW_PACKED:
492 			info_packet->sb[5] = (0x6 << 4);
493 			break;
494 
495 		default:
496 			break;
497 		}
498 
499 		if (hdmi_vic_mode)
500 			info_packet->sb[5] = stream->timing.hdmi_vic;
501 
502 		info_packet->hb0 = HDMI_INFOFRAME_TYPE_VENDOR;
503 		info_packet->hb1 = 0x01;
504 		info_packet->hb2 = (uint8_t) (length);
505 
506 		checksum += info_packet->hb0;
507 		checksum += info_packet->hb1;
508 		checksum += info_packet->hb2;
509 
510 		for (i = 1; i <= length; i++)
511 			checksum += info_packet->sb[i];
512 
513 		info_packet->sb[0] = (uint8_t) (0x100 - checksum);
514 
515 		info_packet->valid = true;
516 }
517 
518