129 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * altera-comp.c4 *5 * altera FPGA driver6 *7 * Copyright (C) Altera Corporation 1998-20018 * Copyright (C) 2010 NetUP Inc.9 * Copyright (C) 2010 Igor M. Liplianin <liplianin@netup.ru>10 */11 12#include <linux/kernel.h>13#include "altera-exprt.h"14 15#define SHORT_BITS 1616#define CHAR_BITS 817#define DATA_BLOB_LENGTH 318#define MATCH_DATA_LENGTH 819219#define ALTERA_REQUEST_SIZE 102420#define ALTERA_BUFFER_SIZE (MATCH_DATA_LENGTH + ALTERA_REQUEST_SIZE)21 22static u32 altera_bits_req(u32 n)23{24 u32 result = SHORT_BITS;25 26 if (n == 0)27 result = 1;28 else {29 /* Look for the highest non-zero bit position */30 while ((n & (1 << (SHORT_BITS - 1))) == 0) {31 n <<= 1;32 --result;33 }34 }35 36 return result;37}38 39static u32 altera_read_packed(u8 *buffer, u32 bits, u32 *bits_avail,40 u32 *in_index)41{42 u32 result = 0;43 u32 shift = 0;44 u32 databyte = 0;45 46 while (bits > 0) {47 databyte = buffer[*in_index];48 result |= (((databyte >> (CHAR_BITS - *bits_avail))49 & (0xff >> (CHAR_BITS - *bits_avail))) << shift);50 51 if (bits <= *bits_avail) {52 result &= (0xffff >> (SHORT_BITS - (bits + shift)));53 *bits_avail -= bits;54 bits = 0;55 } else {56 ++(*in_index);57 shift += *bits_avail;58 bits -= *bits_avail;59 *bits_avail = CHAR_BITS;60 }61 }62 63 return result;64}65 66u32 altera_shrink(u8 *in, u32 in_length, u8 *out, u32 out_length, s32 version)67{68 u32 i, j, data_length = 0L;69 u32 offset, length;70 u32 match_data_length = MATCH_DATA_LENGTH;71 u32 bits_avail = CHAR_BITS;72 u32 in_index = 0L;73 74 if (version > 0)75 --match_data_length;76 77 for (i = 0; i < out_length; ++i)78 out[i] = 0;79 80 /* Read number of bytes in data. */81 for (i = 0; i < sizeof(in_length); ++i) {82 data_length = data_length | (83 altera_read_packed(in,84 CHAR_BITS,85 &bits_avail,86 &in_index) << (i * CHAR_BITS));87 }88 89 if (data_length > out_length) {90 data_length = 0L;91 return data_length;92 }93 94 i = 0;95 while (i < data_length) {96 /* A 0 bit indicates literal data. */97 if (altera_read_packed(in, 1, &bits_avail,98 &in_index) == 0) {99 for (j = 0; j < DATA_BLOB_LENGTH; ++j) {100 if (i < data_length) {101 out[i] = (u8)altera_read_packed(in,102 CHAR_BITS,103 &bits_avail,104 &in_index);105 i++;106 }107 }108 } else {109 /* A 1 bit indicates offset/length to follow. */110 offset = altera_read_packed(in, altera_bits_req((s16)111 (i > match_data_length ?112 match_data_length : i)),113 &bits_avail,114 &in_index);115 length = altera_read_packed(in, CHAR_BITS,116 &bits_avail,117 &in_index);118 for (j = 0; j < length; ++j) {119 if (i < data_length) {120 out[i] = out[i - offset];121 i++;122 }123 }124 }125 }126 127 return data_length;128}129