linux/drivers/media/pci/cx18/cx18-av-vbi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  cx18 ADEC VBI functions
 *
 *  Derived from cx25840-vbi.c
 *
 *  Copyright (C) 2007  Hans Verkuil <hverkuil@xs4all.nl>
 */


#include "cx18-driver.h"

/*
 * For sliced VBI output, we set up to use VIP-1.1, 8-bit mode,
 * NN counts 1 byte Dwords, an IDID with the VBI line # in it.
 * Thus, according to the VIP-2 Spec, our VBI ancillary data lines
 * (should!) look like:
 *	4 byte EAV code:          0xff 0x00 0x00 0xRP
 *	unknown number of possible idle bytes
 *	3 byte Anc data preamble: 0x00 0xff 0xff
 *	1 byte data identifier:   ne010iii (parity bits, 010, DID bits)
 *	1 byte secondary data id: nessssss (parity bits, SDID bits)
 *	1 byte data word count:   necccccc (parity bits, NN Dword count)
 *	2 byte Internal DID:	  VBI-line-# 0x80
 *	NN data bytes
 *	1 byte checksum
 *	Fill bytes needed to fil out to 4*NN bytes of payload
 *
 * The RP codes for EAVs when in VIP-1.1 mode, not in raw mode, &
 * in the vertical blanking interval are:
 *	0xb0 (Task         0 VerticalBlank HorizontalBlank 0 0 0 0)
 *	0xf0 (Task EvenField VerticalBlank HorizontalBlank 0 0 0 0)
 *
 * Since the V bit is only allowed to toggle in the EAV RP code, just
 * before the first active region line and for active lines, they are:
 *	0x90 (Task         0 0 HorizontalBlank 0 0 0 0)
 *	0xd0 (Task EvenField 0 HorizontalBlank 0 0 0 0)
 *
 * The user application DID bytes we care about are:
 *	0x91 (1 0 010        0 !ActiveLine AncDataPresent)
 *	0x55 (0 1 010 2ndField !ActiveLine AncDataPresent)
 *
 */
static const u8 sliced_vbi_did[2] = { 0x91, 0x55 };

struct vbi_anc_data {
	/* u8 eav[4]; */
	/* u8 idle[]; Variable number of idle bytes */
	u8 preamble[3];
	u8 did;
	u8 sdid;
	u8 data_count;
	u8 idid[2];
	u8 payload[1]; /* data_count of payload */
	/* u8 checksum; */
	/* u8 fill[]; Variable number of fill bytes */
};

static int odd_parity(u8 c)
{
	c ^= (c >> 4);
	c ^= (c >> 2);
	c ^= (c >> 1);

	return c & 1;
}

static int decode_vps(u8 *dst, u8 *p)
{
	static const u8 biphase_tbl[] = {
		0xf0, 0x78, 0x70, 0xf0, 0xb4, 0x3c, 0x34, 0xb4,
		0xb0, 0x38, 0x30, 0xb0, 0xf0, 0x78, 0x70, 0xf0,
		0xd2, 0x5a, 0x52, 0xd2, 0x96, 0x1e, 0x16, 0x96,
		0x92, 0x1a, 0x12, 0x92, 0xd2, 0x5a, 0x52, 0xd2,
		0xd0, 0x58, 0x50, 0xd0, 0x94, 0x1c, 0x14, 0x94,
		0x90, 0x18, 0x10, 0x90, 0xd0, 0x58, 0x50, 0xd0,
		0xf0, 0x78, 0x70, 0xf0, 0xb4, 0x3c, 0x34, 0xb4,
		0xb0, 0x38, 0x30, 0xb0, 0xf0, 0x78, 0x70, 0xf0,
		0xe1, 0x69, 0x61, 0xe1, 0xa5, 0x2d, 0x25, 0xa5,
		0xa1, 0x29, 0x21, 0xa1, 0xe1, 0x69, 0x61, 0xe1,
		0xc3, 0x4b, 0x43, 0xc3, 0x87, 0x0f, 0x07, 0x87,
		0x83, 0x0b, 0x03, 0x83, 0xc3, 0x4b, 0x43, 0xc3,
		0xc1, 0x49, 0x41, 0xc1, 0x85, 0x0d, 0x05, 0x85,
		0x81, 0x09, 0x01, 0x81, 0xc1, 0x49, 0x41, 0xc1,
		0xe1, 0x69, 0x61, 0xe1, 0xa5, 0x2d, 0x25, 0xa5,
		0xa1, 0x29, 0x21, 0xa1, 0xe1, 0x69, 0x61, 0xe1,
		0xe0, 0x68, 0x60, 0xe0, 0xa4, 0x2c, 0x24, 0xa4,
		0xa0, 0x28, 0x20, 0xa0, 0xe0, 0x68, 0x60, 0xe0,
		0xc2, 0x4a, 0x42, 0xc2, 0x86, 0x0e, 0x06, 0x86,
		0x82, 0x0a, 0x02, 0x82, 0xc2, 0x4a, 0x42, 0xc2,
		0xc0, 0x48, 0x40, 0xc0, 0x84, 0x0c, 0x04, 0x84,
		0x80, 0x08, 0x00, 0x80, 0xc0, 0x48, 0x40, 0xc0,
		0xe0, 0x68, 0x60, 0xe0, 0xa4, 0x2c, 0x24, 0xa4,
		0xa0, 0x28, 0x20, 0xa0, 0xe0, 0x68, 0x60, 0xe0,
		0xf0, 0x78, 0x70, 0xf0, 0xb4, 0x3c, 0x34, 0xb4,
		0xb0, 0x38, 0x30, 0xb0, 0xf0, 0x78, 0x70, 0xf0,
		0xd2, 0x5a, 0x52, 0xd2, 0x96, 0x1e, 0x16, 0x96,
		0x92, 0x1a, 0x12, 0x92, 0xd2, 0x5a, 0x52, 0xd2,
		0xd0, 0x58, 0x50, 0xd0, 0x94, 0x1c, 0x14, 0x94,
		0x90, 0x18, 0x10, 0x90, 0xd0, 0x58, 0x50, 0xd0,
		0xf0, 0x78, 0x70, 0xf0, 0xb4, 0x3c, 0x34, 0xb4,
		0xb0, 0x38, 0x30, 0xb0, 0xf0, 0x78, 0x70, 0xf0,
	};

	u8 c, err = 0;
	int i;

	for (i = 0; i < 2 * 13; i += 2) {
		err |= biphase_tbl[p[i]] | biphase_tbl[p[i + 1]];
		c = (biphase_tbl[p[i + 1]] & 0xf) |
		    ((biphase_tbl[p[i]] & 0xf) << 4);
		dst[i / 2] = c;
	}

	return err & 0xf0;
}

int cx18_av_g_sliced_fmt(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_format *svbi)
{
	struct cx18 *cx = v4l2_get_subdevdata(sd);
	struct cx18_av_state *state = &cx->av_state;
	static const u16 lcr2vbi[] = {
		0, V4L2_SLICED_TELETEXT_B, 0,	/* 1 */
		0, V4L2_SLICED_WSS_625, 0,	/* 4 */
		V4L2_SLICED_CAPTION_525,	/* 6 */
		0, 0, V4L2_SLICED_VPS, 0, 0,	/* 9 */
		0, 0, 0, 0
	};
	int is_pal = !(state->std & V4L2_STD_525_60);
	int i;

	memset(svbi->service_lines, 0, sizeof(svbi->service_lines));
	svbi->service_set = 0;

	/* we're done if raw VBI is active */
	if ((cx18_av_read(cx, 0x404) & 0x10) == 0)
		return 0;

	if (is_pal) {
		for (i = 7; i <= 23; i++) {
			u8 v = cx18_av_read(cx, 0x424 + i - 7);

			svbi->service_lines[0][i] = lcr2vbi[v >> 4];
			svbi->service_lines[1][i] = lcr2vbi[v & 0xf];
			svbi->service_set |= svbi->service_lines[0][i] |
				svbi->service_lines[1][i];
		}
	} else {
		for (i = 10; i <= 21; i++) {
			u8 v = cx18_av_read(cx, 0x424 + i - 10);

			svbi->service_lines[0][i] = lcr2vbi[v >> 4];
			svbi->service_lines[1][i] = lcr2vbi[v & 0xf];
			svbi->service_set |= svbi->service_lines[0][i] |
				svbi->service_lines[1][i];
		}
	}
	return 0;
}

int cx18_av_s_raw_fmt(struct v4l2_subdev *sd, struct v4l2_vbi_format *fmt)
{
	struct cx18 *cx = v4l2_get_subdevdata(sd);
	struct cx18_av_state *state = &cx->av_state;

	/* Setup standard */
	cx18_av_std_setup(cx);

	/* VBI Offset */
	cx18_av_write(cx, 0x47f, state->slicer_line_delay);
	cx18_av_write(cx, 0x404, 0x2e);
	return 0;
}

int cx18_av_s_sliced_fmt(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_format *svbi)
{
	struct cx18 *cx = v4l2_get_subdevdata(sd);
	struct cx18_av_state *state = &cx->av_state;
	int is_pal = !(state->std & V4L2_STD_525_60);
	int i, x;
	u8 lcr[24];

	for (x = 0; x <= 23; x++)
		lcr[x] = 0x00;

	/* Setup standard */
	cx18_av_std_setup(cx);

	/* Sliced VBI */
	cx18_av_write(cx, 0x404, 0x32);	/* Ancillary data */
	cx18_av_write(cx, 0x406, 0x13);
	cx18_av_write(cx, 0x47f, state->slicer_line_delay);

	/* Force impossible lines to 0 */
	if (is_pal) {
		for (i = 0; i <= 6; i++)
			svbi->service_lines[0][i] =
				svbi->service_lines[1][i] = 0;
	} else {
		for (i = 0; i <= 9; i++)
			svbi->service_lines[0][i] =
				svbi->service_lines[1][i] = 0;

		for (i = 22; i <= 23; i++)
			svbi->service_lines[0][i] =
				svbi->service_lines[1][i] = 0;
	}

	/* Build register values for requested service lines */
	for (i = 7; i <= 23; i++) {
		for (x = 0; x <= 1; x++) {
			switch (svbi->service_lines[1-x][i]) {
			case V4L2_SLICED_TELETEXT_B:
				lcr[i] |= 1 << (4 * x);
				break;
			case V4L2_SLICED_WSS_625:
				lcr[i] |= 4 << (4 * x);
				break;
			case V4L2_SLICED_CAPTION_525:
				lcr[i] |= 6 << (4 * x);
				break;
			case V4L2_SLICED_VPS:
				lcr[i] |= 9 << (4 * x);
				break;
			}
		}
	}

	if (is_pal) {
		for (x = 1, i = 0x424; i <= 0x434; i++, x++)
			cx18_av_write(cx, i, lcr[6 + x]);
	} else {
		for (x = 1, i = 0x424; i <= 0x430; i++, x++)
			cx18_av_write(cx, i, lcr[9 + x]);
		for (i = 0x431; i <= 0x434; i++)
			cx18_av_write(cx, i, 0);
	}

	cx18_av_write(cx, 0x43c, 0x16);
	/* Should match vblank set in cx18_av_std_setup() */
	cx18_av_write(cx, 0x474, is_pal ? 38 : 26);
	return 0;
}

int cx18_av_decode_vbi_line(struct v4l2_subdev *sd,
				   struct v4l2_decode_vbi_line *vbi)
{
	struct cx18 *cx = v4l2_get_subdevdata(sd);
	struct cx18_av_state *state = &cx->av_state;
	struct vbi_anc_data *anc = (struct vbi_anc_data *)vbi->p;
	u8 *p;
	int did, sdid, l, err = 0;

	/*
	 * Check for the ancillary data header for sliced VBI
	 */
	if (anc->preamble[0] ||
			anc->preamble[1] != 0xff || anc->preamble[2] != 0xff ||
			(anc->did != sliced_vbi_did[0] &&
			 anc->did != sliced_vbi_did[1])) {
		vbi->line = vbi->type = 0;
		return 0;
	}

	did = anc->did;
	sdid = anc->sdid & 0xf;
	l = anc->idid[0] & 0x3f;
	l += state->slicer_line_offset;
	p = anc->payload;

	/* Decode the SDID set by the slicer */
	switch (sdid) {
	case 1:
		sdid = V4L2_SLICED_TELETEXT_B;
		break;
	case 4:
		sdid = V4L2_SLICED_WSS_625;
		break;
	case 6:
		sdid = V4L2_SLICED_CAPTION_525;
		err = !odd_parity(p[0]) || !odd_parity(p[1]);
		break;
	case 9:
		sdid = V4L2_SLICED_VPS;
		if (decode_vps(p, p) != 0)
			err = 1;
		break;
	default:
		sdid = 0;
		err = 1;
		break;
	}

	vbi->type = err ? 0 : sdid;
	vbi->line = err ? 0 : l;
	vbi->is_second_field = err ? 0 : (did == sliced_vbi_did[1]);
	vbi->p = p;
	return 0;
}