// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  cx18 Vertical Blank Interval support functions
 *
 *  Derived from ivtv-vbi.c
 *
 *  Copyright (C) 2007  Hans Verkuil <hverkuil@kernel.org>
 */

#include "cx18-driver.h"
#include "cx18-vbi.h"
#include "cx18-ioctl.h"
#include "cx18-queue.h"

/*
 * Raster Reference/Protection (RP) bytes, used in Start/End Active
 * Video codes emitted from the digitzer in VIP 1.x mode, that flag the start
 * of VBI sample or VBI ancillary data regions in the digital ratser line.
 *
 * Task FieldEven VerticalBlank HorizontalBlank 0 0 0 0
 */
static const u8 raw_vbi_sav_rp[2] = { 0x20, 0x60 };    /* __V_, _FV_ */
static const u8 sliced_vbi_eav_rp[2] = { 0xb0, 0xf0 }; /* T_VH, TFVH */

static void copy_vbi_data(struct cx18 *cx, int lines, u32 pts_stamp)
{
        int line = 0;
        int i;
        u32 linemask[2] = { 0, 0 };
        unsigned short size;
        static const u8 mpeg_hdr_data[] = {
                /* MPEG-2 Program Pack */
                0x00, 0x00, 0x01, 0xba,             /* Prog Pack start code */
                0x44, 0x00, 0x0c, 0x66, 0x24, 0x01, /* SCR, SCR Ext, markers */
                0x01, 0xd1, 0xd3,                   /* Mux Rate, markers */
                0xfa, 0xff, 0xff,                   /* Res, Suff cnt, Stuff */
                /* MPEG-2 Private Stream 1 PES Packet */
                0x00, 0x00, 0x01, 0xbd,             /* Priv Stream 1 start */
                0x00, 0x1a,                         /* length */
                0x84, 0x80, 0x07,                   /* flags, hdr data len */
                0x21, 0x00, 0x5d, 0x63, 0xa7,       /* PTS, markers */
                0xff, 0xff                          /* stuffing */
        };
        const int sd = sizeof(mpeg_hdr_data);   /* start of vbi data */
        int idx = cx->vbi.frame % CX18_VBI_FRAMES;
        u8 *dst = &cx->vbi.sliced_mpeg_data[idx][0];

        for (i = 0; i < lines; i++) {
                struct v4l2_sliced_vbi_data *sdata = cx->vbi.sliced_data + i;
                int f, l;

                if (sdata->id == 0)
                        continue;

                l = sdata->line - 6;
                f = sdata->field;
                if (f)
                        l += 18;
                if (l < 32)
                        linemask[0] |= (1 << l);
                else
                        linemask[1] |= (1 << (l - 32));
                dst[sd + 12 + line * 43] = cx18_service2vbi(sdata->id);
                memcpy(dst + sd + 12 + line * 43 + 1, sdata->data, 42);
                line++;
        }
        memcpy(dst, mpeg_hdr_data, sizeof(mpeg_hdr_data));
        if (line == 36) {
                /* All lines are used, so there is no space for the linemask
                   (the max size of the VBI data is 36 * 43 + 4 bytes).
                   So in this case we use the magic number 'ITV0'. */
                memcpy(dst + sd, "ITV0", 4);
                memmove(dst + sd + 4, dst + sd + 12, line * 43);
                size = 4 + ((43 * line + 3) & ~3);
        } else {
                memcpy(dst + sd, "itv0", 4);
                cpu_to_le32s(&linemask[0]);
                cpu_to_le32s(&linemask[1]);
                memcpy(dst + sd + 4, &linemask[0], 8);
                size = 12 + ((43 * line + 3) & ~3);
        }
        dst[4+16] = (size + 10) >> 8;
        dst[5+16] = (size + 10) & 0xff;
        dst[9+16] = 0x21 | ((pts_stamp >> 29) & 0x6);
        dst[10+16] = (pts_stamp >> 22) & 0xff;
        dst[11+16] = 1 | ((pts_stamp >> 14) & 0xff);
        dst[12+16] = (pts_stamp >> 7) & 0xff;
        dst[13+16] = 1 | ((pts_stamp & 0x7f) << 1);
        cx->vbi.sliced_mpeg_size[idx] = sd + size;
}

/* Compress raw VBI format, removes leading SAV codes and surplus space
   after the frame.  Returns new compressed size. */
/* FIXME - this function ignores the input size. */
static u32 compress_raw_buf(struct cx18 *cx, u8 *buf, u32 size, u32 hdr_size)
{
        u32 line_size = VBI_ACTIVE_SAMPLES;
        u32 lines = cx->vbi.count * 2;
        u8 *q = buf;
        u8 *p;
        int i;

        /* Skip the header */
        buf += hdr_size;

        for (i = 0; i < lines; i++) {
                p = buf + i * line_size;

                /* Look for SAV code */
                if (p[0] != 0xff || p[1] || p[2] ||
                    (p[3] != raw_vbi_sav_rp[0] &&
                     p[3] != raw_vbi_sav_rp[1]))
                        break;
                if (i == lines - 1) {
                        /* last line is hdr_size bytes short - extrapolate it */
                        memcpy(q, p + 4, line_size - 4 - hdr_size);
                        q += line_size - 4 - hdr_size;
                        p += line_size - hdr_size - 1;
                        memset(q, (int) *p, hdr_size);
                } else {
                        memcpy(q, p + 4, line_size - 4);
                        q += line_size - 4;
                }
        }
        return lines * (line_size - 4);
}

static u32 compress_sliced_buf(struct cx18 *cx, u8 *buf, u32 size,
                               const u32 hdr_size)
{
        struct v4l2_decode_vbi_line vbi;
        int i;
        u32 line = 0;
        u32 line_size = cx->is_60hz ? VBI_HBLANK_SAMPLES_60HZ
                                    : VBI_HBLANK_SAMPLES_50HZ;

        /* find the first valid line */
        for (i = hdr_size, buf += hdr_size; i < size; i++, buf++) {
                if (buf[0] == 0xff && !buf[1] && !buf[2] &&
                    (buf[3] == sliced_vbi_eav_rp[0] ||
                     buf[3] == sliced_vbi_eav_rp[1]))
                        break;
        }

        /*
         * The last line is short by hdr_size bytes, but for the remaining
         * checks against size, we pretend that it is not, by counting the
         * header bytes we knowingly skipped
         */
        size -= (i - hdr_size);
        if (size < line_size)
                return line;

        for (i = 0; i < size / line_size; i++) {
                u8 *p = buf + i * line_size;

                /* Look for EAV code  */
                if (p[0] != 0xff || p[1] || p[2] ||
                    (p[3] != sliced_vbi_eav_rp[0] &&
                     p[3] != sliced_vbi_eav_rp[1]))
                        continue;
                vbi.p = p + 4;
                v4l2_subdev_call(cx->sd_av, vbi, decode_vbi_line, &vbi);
                if (vbi.type) {
                        cx->vbi.sliced_data[line].id = vbi.type;
                        cx->vbi.sliced_data[line].field = vbi.is_second_field;
                        cx->vbi.sliced_data[line].line = vbi.line;
                        memcpy(cx->vbi.sliced_data[line].data, vbi.p, 42);
                        line++;
                }
        }
        return line;
}

static void _cx18_process_vbi_data(struct cx18 *cx, struct cx18_buffer *buf)
{
        /*
         * The CX23418 provides a 12 byte header in its raw VBI buffers to us:
         * 0x3fffffff [4 bytes of something] [4 byte presentation time stamp]
         */
        struct vbi_data_hdr {
                __be32 magic;
                __be32 unknown;
                __be32 pts;
        } *hdr = (struct vbi_data_hdr *) buf->buf;

        u8 *p = (u8 *) buf->buf;
        u32 size = buf->bytesused;
        u32 pts;
        int lines;

        /*
         * The CX23418 sends us data that is 32 bit little-endian swapped,
         * but we want the raw VBI bytes in the order they were in the raster
         * line.  This has a side effect of making the header big endian
         */
        cx18_buf_swap(buf);

        /* Raw VBI data */
        if (cx18_raw_vbi(cx)) {

                size = buf->bytesused =
                     compress_raw_buf(cx, p, size, sizeof(struct vbi_data_hdr));

                /*
                 * Hack needed for compatibility with old VBI software.
                 * Write the frame # at the last 4 bytes of the frame
                 */
                p += size - 4;
                memcpy(p, &cx->vbi.frame, 4);
                cx->vbi.frame++;
                return;
        }

        /* Sliced VBI data with data insertion */

        pts = (be32_to_cpu(hdr->magic) == 0x3fffffff) ? be32_to_cpu(hdr->pts)
                                                      : 0;

        lines = compress_sliced_buf(cx, p, size, sizeof(struct vbi_data_hdr));

        /* always return at least one empty line */
        if (lines == 0) {
                cx->vbi.sliced_data[0].id = 0;
                cx->vbi.sliced_data[0].line = 0;
                cx->vbi.sliced_data[0].field = 0;
                lines = 1;
        }
        buf->bytesused = size = lines * sizeof(cx->vbi.sliced_data[0]);
        memcpy(p, &cx->vbi.sliced_data[0], size);

        if (cx->vbi.insert_mpeg)
                copy_vbi_data(cx, lines, pts);
        cx->vbi.frame++;
}

void cx18_process_vbi_data(struct cx18 *cx, struct cx18_mdl *mdl,
                           int streamtype)
{
        struct cx18_buffer *buf;
        u32 orig_used;

        if (streamtype != CX18_ENC_STREAM_TYPE_VBI)
                return;

        /*
         * Big assumption here:
         * Every buffer hooked to the MDL's buf_list is a complete VBI frame
         * that ends at the end of the buffer.
         *
         * To assume anything else would make the code in this file
         * more complex, or require extra memcpy()'s to make the
         * buffers satisfy the above assumption.  It's just simpler to set
         * up the encoder buffer transfers to make the assumption true.
         */
        list_for_each_entry(buf, &mdl->buf_list, list) {
                orig_used = buf->bytesused;
                if (orig_used == 0)
                        break;
                _cx18_process_vbi_data(cx, buf);
                mdl->bytesused -= (orig_used - buf->bytesused);
        }
}