312 lines
		
	
	
		
			8.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			312 lines
		
	
	
		
			8.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| // SPDX-License-Identifier: GPL-2.0-only
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| /*
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|  * vivid-vbi-gen.c - vbi generator support functions.
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|  *
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|  * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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|  */
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| 
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| #include <linux/errno.h>
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| #include <linux/kernel.h>
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| #include <linux/ktime.h>
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| #include <linux/string.h>
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| #include <linux/videodev2.h>
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| 
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| #include "vivid-vbi-gen.h"
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| 
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| static void wss_insert(u8 *wss, u32 val, unsigned size)
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| {
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| 	while (size--)
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| 		*wss++ = (val & (1 << size)) ? 0xc0 : 0x10;
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| }
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| 
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| static void vivid_vbi_gen_wss_raw(const struct v4l2_sliced_vbi_data *data,
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| 		u8 *buf, unsigned sampling_rate)
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| {
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| 	const unsigned rate = 5000000;	/* WSS has a 5 MHz transmission rate */
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| 	u8 wss[29 + 24 + 24 + 24 + 18 + 18] = { 0 };
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| 	const unsigned zero = 0x07;
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| 	const unsigned one = 0x38;
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| 	unsigned bit = 0;
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| 	u16 wss_data;
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| 	int i;
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| 
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| 	wss_insert(wss + bit, 0x1f1c71c7, 29); bit += 29;
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| 	wss_insert(wss + bit, 0x1e3c1f, 24); bit += 24;
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| 
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| 	wss_data = (data->data[1] << 8) | data->data[0];
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| 	for (i = 0; i <= 13; i++, bit += 6)
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| 		wss_insert(wss + bit, (wss_data & (1 << i)) ? one : zero, 6);
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| 
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| 	for (i = 0, bit = 0; bit < sizeof(wss); bit++) {
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| 		unsigned n = ((bit + 1) * sampling_rate) / rate;
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| 
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| 		while (i < n)
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| 			buf[i++] = wss[bit];
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| 	}
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| }
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| 
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| static void vivid_vbi_gen_teletext_raw(const struct v4l2_sliced_vbi_data *data,
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| 		u8 *buf, unsigned sampling_rate)
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| {
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| 	const unsigned rate = 6937500 / 10;	/* Teletext has a 6.9375 MHz transmission rate */
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| 	u8 teletext[45] = { 0x55, 0x55, 0x27 };
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| 	unsigned bit = 0;
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| 	int i;
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| 
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| 	memcpy(teletext + 3, data->data, sizeof(teletext) - 3);
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| 	/* prevents 32 bit overflow */
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| 	sampling_rate /= 10;
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| 
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| 	for (i = 0, bit = 0; bit < sizeof(teletext) * 8; bit++) {
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| 		unsigned n = ((bit + 1) * sampling_rate) / rate;
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| 		u8 val = (teletext[bit / 8] & (1 << (bit & 7))) ? 0xc0 : 0x10;
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| 
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| 		while (i < n)
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| 			buf[i++] = val;
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| 	}
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| }
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| 
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| static void cc_insert(u8 *cc, u8 ch)
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| {
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| 	unsigned tot = 0;
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| 	unsigned i;
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| 
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| 	for (i = 0; i < 7; i++) {
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| 		cc[2 * i] = cc[2 * i + 1] = (ch & (1 << i)) ? 1 : 0;
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| 		tot += cc[2 * i];
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| 	}
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| 	cc[14] = cc[15] = !(tot & 1);
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| }
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| 
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| #define CC_PREAMBLE_BITS (14 + 4 + 2)
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| 
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| static void vivid_vbi_gen_cc_raw(const struct v4l2_sliced_vbi_data *data,
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| 		u8 *buf, unsigned sampling_rate)
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| {
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| 	const unsigned rate = 1000000;	/* CC has a 1 MHz transmission rate */
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| 
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| 	u8 cc[CC_PREAMBLE_BITS + 2 * 16] = {
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| 		/* Clock run-in: 7 cycles */
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| 		0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
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| 		/* 2 cycles of 0 */
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| 		0, 0, 0, 0,
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| 		/* Start bit of 1 (each bit is two cycles) */
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| 		1, 1
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| 	};
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| 	unsigned bit, i;
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| 
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| 	cc_insert(cc + CC_PREAMBLE_BITS, data->data[0]);
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| 	cc_insert(cc + CC_PREAMBLE_BITS + 16, data->data[1]);
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| 
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| 	for (i = 0, bit = 0; bit < sizeof(cc); bit++) {
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| 		unsigned n = ((bit + 1) * sampling_rate) / rate;
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| 
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| 		while (i < n)
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| 			buf[i++] = cc[bit] ? 0xc0 : 0x10;
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| 	}
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| }
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| 
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| void vivid_vbi_gen_raw(const struct vivid_vbi_gen_data *vbi,
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| 		const struct v4l2_vbi_format *vbi_fmt, u8 *buf)
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| {
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| 	unsigned idx;
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| 
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| 	for (idx = 0; idx < 25; idx++) {
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| 		const struct v4l2_sliced_vbi_data *data = vbi->data + idx;
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| 		unsigned start_2nd_field;
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| 		unsigned line = data->line;
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| 		u8 *linebuf = buf;
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| 
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| 		start_2nd_field = (data->id & V4L2_SLICED_VBI_525) ? 263 : 313;
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| 		if (data->field)
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| 			line += start_2nd_field;
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| 		line -= vbi_fmt->start[data->field];
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| 
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| 		if (vbi_fmt->flags & V4L2_VBI_INTERLACED)
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| 			linebuf += (line * 2 + data->field) *
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| 				vbi_fmt->samples_per_line;
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| 		else
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| 			linebuf += (line + data->field * vbi_fmt->count[0]) *
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| 				vbi_fmt->samples_per_line;
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| 		if (data->id == V4L2_SLICED_CAPTION_525)
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| 			vivid_vbi_gen_cc_raw(data, linebuf, vbi_fmt->sampling_rate);
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| 		else if (data->id == V4L2_SLICED_WSS_625)
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| 			vivid_vbi_gen_wss_raw(data, linebuf, vbi_fmt->sampling_rate);
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| 		else if (data->id == V4L2_SLICED_TELETEXT_B)
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| 			vivid_vbi_gen_teletext_raw(data, linebuf, vbi_fmt->sampling_rate);
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| 	}
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| }
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| 
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| static const u8 vivid_cc_sequence1[30] = {
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| 	0x14, 0x20,	/* Resume Caption Loading */
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| 	'H',  'e',
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| 	'l',  'l',
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| 	'o',  ' ',
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| 	'w',  'o',
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| 	'r',  'l',
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| 	'd',  '!',
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| 	0x14, 0x2f,	/* End of Caption */
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| };
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| 
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| static const u8 vivid_cc_sequence2[30] = {
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| 	0x14, 0x20,	/* Resume Caption Loading */
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| 	'C',  'l',
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| 	'o',  's',
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| 	'e',  'd',
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| 	' ',  'c',
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| 	'a',  'p',
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| 	't',  'i',
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| 	'o',  'n',
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| 	's',  ' ',
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| 	't',  'e',
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| 	's',  't',
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| 	0x14, 0x2f,	/* End of Caption */
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| };
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| 
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| static u8 calc_parity(u8 val)
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| {
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| 	unsigned i;
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| 	unsigned tot = 0;
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| 
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| 	for (i = 0; i < 7; i++)
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| 		tot += (val & (1 << i)) ? 1 : 0;
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| 	return val | ((tot & 1) ? 0 : 0x80);
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| }
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| 
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| static void vivid_vbi_gen_set_time_of_day(u8 *packet)
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| {
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| 	struct tm tm;
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| 	u8 checksum, i;
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| 
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| 	time64_to_tm(ktime_get_real_seconds(), 0, &tm);
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| 	packet[0] = calc_parity(0x07);
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| 	packet[1] = calc_parity(0x01);
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| 	packet[2] = calc_parity(0x40 | tm.tm_min);
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| 	packet[3] = calc_parity(0x40 | tm.tm_hour);
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| 	packet[4] = calc_parity(0x40 | tm.tm_mday);
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| 	if (tm.tm_mday == 1 && tm.tm_mon == 2 &&
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| 	    sys_tz.tz_minuteswest > tm.tm_min + tm.tm_hour * 60)
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| 		packet[4] = calc_parity(0x60 | tm.tm_mday);
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| 	packet[5] = calc_parity(0x40 | (1 + tm.tm_mon));
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| 	packet[6] = calc_parity(0x40 | (1 + tm.tm_wday));
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| 	packet[7] = calc_parity(0x40 | ((tm.tm_year - 90) & 0x3f));
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| 	packet[8] = calc_parity(0x0f);
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| 	for (checksum = i = 0; i <= 8; i++)
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| 		checksum += packet[i] & 0x7f;
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| 	packet[9] = calc_parity(0x100 - checksum);
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| 	checksum = 0;
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| 	packet[10] = calc_parity(0x07);
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| 	packet[11] = calc_parity(0x04);
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| 	if (sys_tz.tz_minuteswest >= 0)
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| 		packet[12] = calc_parity(0x40 | ((sys_tz.tz_minuteswest / 60) & 0x1f));
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| 	else
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| 		packet[12] = calc_parity(0x40 | ((24 + sys_tz.tz_minuteswest / 60) & 0x1f));
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| 	packet[13] = calc_parity(0);
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| 	packet[14] = calc_parity(0x0f);
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| 	for (checksum = 0, i = 10; i <= 14; i++)
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| 		checksum += packet[i] & 0x7f;
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| 	packet[15] = calc_parity(0x100 - checksum);
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| }
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| 
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| static const u8 hamming[16] = {
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| 	0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f,
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| 	0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea
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| };
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| 
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| static void vivid_vbi_gen_teletext(u8 *packet, unsigned line, unsigned frame)
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| {
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| 	unsigned offset = 2;
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| 	unsigned i;
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| 
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| 	packet[0] = hamming[1 + ((line & 1) << 3)];
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| 	packet[1] = hamming[line >> 1];
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| 	memset(packet + 2, 0x20, 40);
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| 	if (line == 0) {
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| 		/* subcode */
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| 		packet[2] = hamming[frame % 10];
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| 		packet[3] = hamming[frame / 10];
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| 		packet[4] = hamming[0];
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| 		packet[5] = hamming[0];
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| 		packet[6] = hamming[0];
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| 		packet[7] = hamming[0];
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| 		packet[8] = hamming[0];
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| 		packet[9] = hamming[1];
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| 		offset = 10;
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| 	}
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| 	packet += offset;
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| 	memcpy(packet, "Page: 100 Row: 10", 17);
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| 	packet[7] = '0' + frame / 10;
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| 	packet[8] = '0' + frame % 10;
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| 	packet[15] = '0' + line / 10;
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| 	packet[16] = '0' + line % 10;
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| 	for (i = 0; i < 42 - offset; i++)
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| 		packet[i] = calc_parity(packet[i]);
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| }
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| 
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| void vivid_vbi_gen_sliced(struct vivid_vbi_gen_data *vbi,
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| 		bool is_60hz, unsigned seqnr)
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| {
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| 	struct v4l2_sliced_vbi_data *data0 = vbi->data;
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| 	struct v4l2_sliced_vbi_data *data1 = vbi->data + 1;
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| 	unsigned frame = seqnr % 60;
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| 
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| 	memset(vbi->data, 0, sizeof(vbi->data));
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| 
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| 	if (!is_60hz) {
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| 		unsigned i;
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| 
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| 		for (i = 0; i <= 11; i++) {
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| 			data0->id = V4L2_SLICED_TELETEXT_B;
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| 			data0->line = 7 + i;
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| 			vivid_vbi_gen_teletext(data0->data, i, frame);
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| 			data0++;
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| 		}
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| 		data0->id = V4L2_SLICED_WSS_625;
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| 		data0->line = 23;
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| 		/* 4x3 video aspect ratio */
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| 		data0->data[0] = 0x08;
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| 		data0++;
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| 		for (i = 0; i <= 11; i++) {
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| 			data0->id = V4L2_SLICED_TELETEXT_B;
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| 			data0->field = 1;
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| 			data0->line = 7 + i;
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| 			vivid_vbi_gen_teletext(data0->data, 12 + i, frame);
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| 			data0++;
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| 		}
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| 		return;
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| 	}
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| 
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| 	data0->id = V4L2_SLICED_CAPTION_525;
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| 	data0->line = 21;
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| 	data1->id = V4L2_SLICED_CAPTION_525;
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| 	data1->field = 1;
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| 	data1->line = 21;
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| 
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| 	if (frame < 15) {
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| 		data0->data[0] = calc_parity(vivid_cc_sequence1[2 * frame]);
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| 		data0->data[1] = calc_parity(vivid_cc_sequence1[2 * frame + 1]);
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| 	} else if (frame >= 30 && frame < 45) {
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| 		frame -= 30;
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| 		data0->data[0] = calc_parity(vivid_cc_sequence2[2 * frame]);
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| 		data0->data[1] = calc_parity(vivid_cc_sequence2[2 * frame + 1]);
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| 	} else {
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| 		data0->data[0] = calc_parity(0);
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| 		data0->data[1] = calc_parity(0);
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| 	}
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| 
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| 	frame = seqnr % (30 * 60);
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| 	switch (frame) {
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| 	case 0:
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| 		vivid_vbi_gen_set_time_of_day(vbi->time_of_day_packet);
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| 		/* fall through */
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| 	case 1 ... 7:
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| 		data1->data[0] = vbi->time_of_day_packet[frame * 2];
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| 		data1->data[1] = vbi->time_of_day_packet[frame * 2 + 1];
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| 		break;
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| 	default:
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| 		data1->data[0] = calc_parity(0);
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| 		data1->data[1] = calc_parity(0);
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| 		break;
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| 	}
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| }
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