cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mtk_jpeg_dec_parse.c (2816B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (c) 2016 MediaTek Inc.
      4 * Author: Ming Hsiu Tsai <minghsiu.tsai@mediatek.com>
      5 *         Rick Chang <rick.chang@mediatek.com>
      6 */
      7
      8#include <linux/kernel.h>
      9#include <linux/videodev2.h>
     10
     11#include "mtk_jpeg_dec_parse.h"
     12
     13#define TEM	0x01
     14#define SOF0	0xc0
     15#define RST	0xd0
     16#define SOI	0xd8
     17#define EOI	0xd9
     18
     19struct mtk_jpeg_stream {
     20	u8 *addr;
     21	u32 size;
     22	u32 curr;
     23};
     24
     25static int read_byte(struct mtk_jpeg_stream *stream)
     26{
     27	if (stream->curr >= stream->size)
     28		return -1;
     29	return stream->addr[stream->curr++];
     30}
     31
     32static int read_word_be(struct mtk_jpeg_stream *stream, u32 *word)
     33{
     34	u32 temp;
     35	int byte;
     36
     37	byte = read_byte(stream);
     38	if (byte == -1)
     39		return -1;
     40	temp = byte << 8;
     41	byte = read_byte(stream);
     42	if (byte == -1)
     43		return -1;
     44	*word = (u32)byte | temp;
     45
     46	return 0;
     47}
     48
     49static void read_skip(struct mtk_jpeg_stream *stream, long len)
     50{
     51	if (len <= 0)
     52		return;
     53	while (len--)
     54		read_byte(stream);
     55}
     56
     57static bool mtk_jpeg_do_parse(struct mtk_jpeg_dec_param *param, u8 *src_addr_va,
     58			      u32 src_size)
     59{
     60	bool notfound = true;
     61	struct mtk_jpeg_stream stream;
     62
     63	stream.addr = src_addr_va;
     64	stream.size = src_size;
     65	stream.curr = 0;
     66
     67	while (notfound) {
     68		int i, length, byte;
     69		u32 word;
     70
     71		byte = read_byte(&stream);
     72		if (byte == -1)
     73			return false;
     74		if (byte != 0xff)
     75			continue;
     76		do
     77			byte = read_byte(&stream);
     78		while (byte == 0xff);
     79		if (byte == -1)
     80			return false;
     81		if (byte == 0)
     82			continue;
     83
     84		length = 0;
     85		switch (byte) {
     86		case SOF0:
     87			/* length */
     88			if (read_word_be(&stream, &word))
     89				break;
     90
     91			/* precision */
     92			if (read_byte(&stream) == -1)
     93				break;
     94
     95			if (read_word_be(&stream, &word))
     96				break;
     97			param->pic_h = word;
     98
     99			if (read_word_be(&stream, &word))
    100				break;
    101			param->pic_w = word;
    102
    103			param->comp_num = read_byte(&stream);
    104			if (param->comp_num != 1 && param->comp_num != 3)
    105				break;
    106
    107			for (i = 0; i < param->comp_num; i++) {
    108				param->comp_id[i] = read_byte(&stream);
    109				if (param->comp_id[i] == -1)
    110					break;
    111
    112				/* sampling */
    113				byte = read_byte(&stream);
    114				if (byte == -1)
    115					break;
    116				param->sampling_w[i] = (byte >> 4) & 0x0F;
    117				param->sampling_h[i] = byte & 0x0F;
    118
    119				param->qtbl_num[i] = read_byte(&stream);
    120				if (param->qtbl_num[i] == -1)
    121					break;
    122			}
    123
    124			notfound = !(i == param->comp_num);
    125			break;
    126		case RST ... RST + 7:
    127		case SOI:
    128		case EOI:
    129		case TEM:
    130			break;
    131		default:
    132			if (read_word_be(&stream, &word))
    133				break;
    134			length = (long)word - 2;
    135			read_skip(&stream, length);
    136			break;
    137		}
    138	}
    139
    140	return !notfound;
    141}
    142
    143bool mtk_jpeg_parse(struct mtk_jpeg_dec_param *param, u8 *src_addr_va,
    144		    u32 src_size)
    145{
    146	if (!mtk_jpeg_do_parse(param, src_addr_va, src_size))
    147		return false;
    148	if (mtk_jpeg_dec_fill_param(param))
    149		return false;
    150
    151	return true;
    152}