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