// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* altera-comp.c
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*
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* altera FPGA driver
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*
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* Copyright (C) Altera Corporation 1998-2001
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* Copyright (C) 2010 NetUP Inc.
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* Copyright (C) 2010 Igor M. Liplianin <liplianin@netup.ru>
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*/
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#include <linux/kernel.h>
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#include "altera-exprt.h"
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#define SHORT_BITS 16
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#define CHAR_BITS 8
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#define DATA_BLOB_LENGTH 3
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#define MATCH_DATA_LENGTH 8192
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#define ALTERA_REQUEST_SIZE 1024
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#define ALTERA_BUFFER_SIZE (MATCH_DATA_LENGTH + ALTERA_REQUEST_SIZE)
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static u32 altera_bits_req(u32 n)
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{
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u32 result = SHORT_BITS;
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if (n == 0)
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result = 1;
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else {
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/* Look for the highest non-zero bit position */
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while ((n & (1 << (SHORT_BITS - 1))) == 0) {
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n <<= 1;
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--result;
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}
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}
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return result;
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}
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static u32 altera_read_packed(u8 *buffer, u32 bits, u32 *bits_avail,
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u32 *in_index)
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{
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u32 result = 0;
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u32 shift = 0;
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u32 databyte = 0;
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while (bits > 0) {
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databyte = buffer[*in_index];
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result |= (((databyte >> (CHAR_BITS - *bits_avail))
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& (0xff >> (CHAR_BITS - *bits_avail))) << shift);
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if (bits <= *bits_avail) {
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result &= (0xffff >> (SHORT_BITS - (bits + shift)));
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*bits_avail -= bits;
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bits = 0;
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} else {
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++(*in_index);
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shift += *bits_avail;
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bits -= *bits_avail;
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*bits_avail = CHAR_BITS;
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}
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}
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return result;
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}
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u32 altera_shrink(u8 *in, u32 in_length, u8 *out, u32 out_length, s32 version)
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{
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u32 i, j, data_length = 0L;
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u32 offset, length;
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u32 match_data_length = MATCH_DATA_LENGTH;
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u32 bits_avail = CHAR_BITS;
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u32 in_index = 0L;
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if (version > 0)
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--match_data_length;
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for (i = 0; i < out_length; ++i)
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out[i] = 0;
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/* Read number of bytes in data. */
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for (i = 0; i < sizeof(in_length); ++i) {
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data_length = data_length | (
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altera_read_packed(in,
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CHAR_BITS,
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&bits_avail,
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&in_index) << (i * CHAR_BITS));
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}
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if (data_length > out_length) {
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data_length = 0L;
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return data_length;
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}
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i = 0;
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while (i < data_length) {
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/* A 0 bit indicates literal data. */
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if (altera_read_packed(in, 1, &bits_avail,
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&in_index) == 0) {
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for (j = 0; j < DATA_BLOB_LENGTH; ++j) {
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if (i < data_length) {
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out[i] = (u8)altera_read_packed(in,
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CHAR_BITS,
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&bits_avail,
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&in_index);
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i++;
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}
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}
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} else {
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/* A 1 bit indicates offset/length to follow. */
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offset = altera_read_packed(in, altera_bits_req((s16)
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(i > match_data_length ?
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match_data_length : i)),
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&bits_avail,
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&in_index);
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length = altera_read_packed(in, CHAR_BITS,
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&bits_avail,
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&in_index);
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for (j = 0; j < length; ++j) {
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if (i < data_length) {
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out[i] = out[i - offset];
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i++;
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}
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}
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}
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}
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return data_length;
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}
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