// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Coda multi-standard codec IP - H.264 helper functions
 *
 * Copyright (C) 2012 Vista Silicon S.L.
 *    Javier Martin, <javier.martin@vista-silicon.com>
 *    Xavier Duret
 */

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/videodev2.h>

#include "coda.h"

static const u8 coda_filler_size[8] = { 0, 7, 14, 13, 12, 11, 10, 9 };

static const u8 *coda_find_nal_header(const u8 *buf, const u8 *end)
{
        u32 val = 0xffffffff;

        do {
                val = val << 8 | *buf++;
                if (buf >= end)
                        return NULL;
        } while (val != 0x00000001);

        return buf;
}

int coda_sps_parse_profile(struct coda_ctx *ctx, struct vb2_buffer *vb)
{
        const u8 *buf = vb2_plane_vaddr(vb, 0);
        const u8 *end = buf + vb2_get_plane_payload(vb, 0);

        /* Find SPS header */
        do {
                buf = coda_find_nal_header(buf, end);
                if (!buf)
                        return -EINVAL;
        } while ((*buf++ & 0x1f) != 0x7);

        ctx->params.h264_profile_idc = buf[0];
        ctx->params.h264_level_idc = buf[2];

        return 0;
}

int coda_h264_filler_nal(int size, char *p)
{
        if (size < 6)
                return -EINVAL;

        p[0] = 0x00;
        p[1] = 0x00;
        p[2] = 0x00;
        p[3] = 0x01;
        p[4] = 0x0c;
        memset(p + 5, 0xff, size - 6);
        /* Add rbsp stop bit and trailing at the end */
        p[size - 1] = 0x80;

        return 0;
}

int coda_h264_padding(int size, char *p)
{
        int nal_size;
        int diff;

        diff = size - (size & ~0x7);
        if (diff == 0)
                return 0;

        nal_size = coda_filler_size[diff];
        coda_h264_filler_nal(nal_size, p);

        return nal_size;
}

int coda_h264_profile(int profile_idc)
{
        switch (profile_idc) {
        case 66: return V4L2_MPEG_VIDEO_H264_PROFILE_BASELINE;
        case 77: return V4L2_MPEG_VIDEO_H264_PROFILE_MAIN;
        case 88: return V4L2_MPEG_VIDEO_H264_PROFILE_EXTENDED;
        case 100: return V4L2_MPEG_VIDEO_H264_PROFILE_HIGH;
        default: return -EINVAL;
        }
}

int coda_h264_level(int level_idc)
{
        switch (level_idc) {
        case 10: return V4L2_MPEG_VIDEO_H264_LEVEL_1_0;
        case 9:  return V4L2_MPEG_VIDEO_H264_LEVEL_1B;
        case 11: return V4L2_MPEG_VIDEO_H264_LEVEL_1_1;
        case 12: return V4L2_MPEG_VIDEO_H264_LEVEL_1_2;
        case 13: return V4L2_MPEG_VIDEO_H264_LEVEL_1_3;
        case 20: return V4L2_MPEG_VIDEO_H264_LEVEL_2_0;
        case 21: return V4L2_MPEG_VIDEO_H264_LEVEL_2_1;
        case 22: return V4L2_MPEG_VIDEO_H264_LEVEL_2_2;
        case 30: return V4L2_MPEG_VIDEO_H264_LEVEL_3_0;
        case 31: return V4L2_MPEG_VIDEO_H264_LEVEL_3_1;
        case 32: return V4L2_MPEG_VIDEO_H264_LEVEL_3_2;
        case 40: return V4L2_MPEG_VIDEO_H264_LEVEL_4_0;
        case 41: return V4L2_MPEG_VIDEO_H264_LEVEL_4_1;
        case 42: return V4L2_MPEG_VIDEO_H264_LEVEL_4_2;
        case 50: return V4L2_MPEG_VIDEO_H264_LEVEL_5_0;
        case 51: return V4L2_MPEG_VIDEO_H264_LEVEL_5_1;
        default: return -EINVAL;
        }
}

struct rbsp {
        char *buf;
        int size;
        int pos;
};

static inline int rbsp_read_bit(struct rbsp *rbsp)
{
        int shift = 7 - (rbsp->pos % 8);
        int ofs = rbsp->pos++ / 8;

        if (ofs >= rbsp->size)
                return -EINVAL;

        return (rbsp->buf[ofs] >> shift) & 1;
}

static inline int rbsp_write_bit(struct rbsp *rbsp, int bit)
{
        int shift = 7 - (rbsp->pos % 8);
        int ofs = rbsp->pos++ / 8;

        if (ofs >= rbsp->size)
                return -EINVAL;

        rbsp->buf[ofs] &= ~(1 << shift);
        rbsp->buf[ofs] |= bit << shift;

        return 0;
}

static inline int rbsp_read_bits(struct rbsp *rbsp, int num, int *val)
{
        int i, ret;
        int tmp = 0;

        if (num > 32)
                return -EINVAL;

        for (i = 0; i < num; i++) {
                ret = rbsp_read_bit(rbsp);
                if (ret < 0)
                        return ret;
                tmp |= ret << (num - i - 1);
        }

        if (val)
                *val = tmp;

        return 0;
}

static int rbsp_write_bits(struct rbsp *rbsp, int num, int value)
{
        int ret;

        while (num--) {
                ret = rbsp_write_bit(rbsp, (value >> num) & 1);
                if (ret)
                        return ret;
        }

        return 0;
}

static int rbsp_read_uev(struct rbsp *rbsp, unsigned int *val)
{
        int leading_zero_bits = 0;
        unsigned int tmp = 0;
        int ret;

        while ((ret = rbsp_read_bit(rbsp)) == 0)
                leading_zero_bits++;
        if (ret < 0)
                return ret;

        if (leading_zero_bits > 0) {
                ret = rbsp_read_bits(rbsp, leading_zero_bits, &tmp);
                if (ret)
                        return ret;
        }

        if (val)
                *val = (1 << leading_zero_bits) - 1 + tmp;

        return 0;
}

static int rbsp_write_uev(struct rbsp *rbsp, unsigned int value)
{
        int i;
        int ret;
        int tmp = value + 1;
        int leading_zero_bits = fls(tmp) - 1;

        for (i = 0; i < leading_zero_bits; i++) {
                ret = rbsp_write_bit(rbsp, 0);
                if (ret)
                        return ret;
        }

        return rbsp_write_bits(rbsp, leading_zero_bits + 1, tmp);
}

static int rbsp_read_sev(struct rbsp *rbsp, int *val)
{
        unsigned int tmp;
        int ret;

        ret = rbsp_read_uev(rbsp, &tmp);
        if (ret)
                return ret;

        if (val) {
                if (tmp & 1)
                        *val = (tmp + 1) / 2;
                else
                        *val = -(tmp / 2);
        }

        return 0;
}

/**
 * coda_h264_sps_fixup - fixes frame cropping values in h.264 SPS
 * @ctx: encoder context
 * @width: visible width
 * @height: visible height
 * @buf: buffer containing h.264 SPS RBSP, starting with NAL header
 * @size: modified RBSP size return value
 * @max_size: available size in buf
 *
 * Rewrites the frame cropping values in an h.264 SPS RBSP correctly for the
 * given visible width and height.
 */
int coda_h264_sps_fixup(struct coda_ctx *ctx, int width, int height, char *buf,
                        int *size, int max_size)
{
        int profile_idc;
        unsigned int pic_order_cnt_type;
        int pic_width_in_mbs_minus1, pic_height_in_map_units_minus1;
        int frame_mbs_only_flag, frame_cropping_flag;
        int vui_parameters_present_flag;
        unsigned int crop_right, crop_bottom;
        struct rbsp sps;
        int pos;
        int ret;

        if (*size < 8 || *size >= max_size)
                return -EINVAL;

        sps.buf = buf + 5; /* Skip NAL header */
        sps.size = *size - 5;

        profile_idc = sps.buf[0];
        /* Skip constraint_set[0-5]_flag, reserved_zero_2bits */
        /* Skip level_idc */
        sps.pos = 24;

        /* seq_parameter_set_id */
        ret = rbsp_read_uev(&sps, NULL);
        if (ret)
                return ret;

        if (profile_idc == 100 || profile_idc == 110 || profile_idc == 122 ||
            profile_idc == 244 || profile_idc == 44 || profile_idc == 83 ||
            profile_idc == 86 || profile_idc == 118 || profile_idc == 128 ||
            profile_idc == 138 || profile_idc == 139 || profile_idc == 134 ||
            profile_idc == 135) {
                dev_err(ctx->fh.vdev->dev_parent,
                        "%s: Handling profile_idc %d not implemented\n",
                        __func__, profile_idc);
                return -EINVAL;
        }

        /* log2_max_frame_num_minus4 */
        ret = rbsp_read_uev(&sps, NULL);
        if (ret)
                return ret;

        ret = rbsp_read_uev(&sps, &pic_order_cnt_type);
        if (ret)
                return ret;

        if (pic_order_cnt_type == 0) {
                /* log2_max_pic_order_cnt_lsb_minus4 */
                ret = rbsp_read_uev(&sps, NULL);
                if (ret)
                        return ret;
        } else if (pic_order_cnt_type == 1) {
                unsigned int i, num_ref_frames_in_pic_order_cnt_cycle;

                /* delta_pic_order_always_zero_flag */
                ret = rbsp_read_bit(&sps);
                if (ret < 0)
                        return ret;
                /* offset_for_non_ref_pic */
                ret = rbsp_read_sev(&sps, NULL);
                if (ret)
                        return ret;
                /* offset_for_top_to_bottom_field */
                ret = rbsp_read_sev(&sps, NULL);
                if (ret)
                        return ret;

                ret = rbsp_read_uev(&sps,
                                    &num_ref_frames_in_pic_order_cnt_cycle);
                if (ret)
                        return ret;
                for (i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++) {
                        /* offset_for_ref_frame */
                        ret = rbsp_read_sev(&sps, NULL);
                        if (ret)
                                return ret;
                }
        }

        /* max_num_ref_frames */
        ret = rbsp_read_uev(&sps, NULL);
        if (ret)
                return ret;

        /* gaps_in_frame_num_value_allowed_flag */
        ret = rbsp_read_bit(&sps);
        if (ret < 0)
                return ret;
        ret = rbsp_read_uev(&sps, &pic_width_in_mbs_minus1);
        if (ret)
                return ret;
        ret = rbsp_read_uev(&sps, &pic_height_in_map_units_minus1);
        if (ret)
                return ret;
        frame_mbs_only_flag = ret = rbsp_read_bit(&sps);
        if (ret < 0)
                return ret;
        if (!frame_mbs_only_flag) {
                /* mb_adaptive_frame_field_flag */
                ret = rbsp_read_bit(&sps);
                if (ret < 0)
                        return ret;
        }
        /* direct_8x8_inference_flag */
        ret = rbsp_read_bit(&sps);
        if (ret < 0)
                return ret;

        /* Mark position of the frame cropping flag */
        pos = sps.pos;
        frame_cropping_flag = ret = rbsp_read_bit(&sps);
        if (ret < 0)
                return ret;
        if (frame_cropping_flag) {
                unsigned int crop_left, crop_top;

                ret = rbsp_read_uev(&sps, &crop_left);
                if (ret)
                        return ret;
                ret = rbsp_read_uev(&sps, &crop_right);
                if (ret)
                        return ret;
                ret = rbsp_read_uev(&sps, &crop_top);
                if (ret)
                        return ret;
                ret = rbsp_read_uev(&sps, &crop_bottom);
                if (ret)
                        return ret;
        }
        vui_parameters_present_flag = ret = rbsp_read_bit(&sps);
        if (ret < 0)
                return ret;
        if (vui_parameters_present_flag) {
                dev_err(ctx->fh.vdev->dev_parent,
                        "%s: Handling vui_parameters not implemented\n",
                        __func__);
                return -EINVAL;
        }

        crop_right = round_up(width, 16) - width;
        crop_bottom = round_up(height, 16) - height;
        crop_right /= 2;
        if (frame_mbs_only_flag)
                crop_bottom /= 2;
        else
                crop_bottom /= 4;


        sps.size = max_size - 5;
        sps.pos = pos;
        frame_cropping_flag = 1;
        ret = rbsp_write_bit(&sps, frame_cropping_flag);
        if (ret)
                return ret;
        ret = rbsp_write_uev(&sps, 0); /* crop_left */
        if (ret)
                return ret;
        ret = rbsp_write_uev(&sps, crop_right);
        if (ret)
                return ret;
        ret = rbsp_write_uev(&sps, 0); /* crop_top */
        if (ret)
                return ret;
        ret = rbsp_write_uev(&sps, crop_bottom);
        if (ret)
                return ret;
        ret = rbsp_write_bit(&sps, 0); /* vui_parameters_present_flag */
        if (ret)
                return ret;
        ret = rbsp_write_bit(&sps, 1);
        if (ret)
                return ret;

        *size = 5 + DIV_ROUND_UP(sps.pos, 8);

        return 0;
}