631 строка
14 KiB
C
631 строка
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* 842 Software Compression
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*
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* Copyright (C) 2015 Dan Streetman, IBM Corp
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*
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* See 842.h for details of the 842 compressed format.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#define MODULE_NAME "842_compress"
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#include <linux/hashtable.h>
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#include "842.h"
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#include "842_debugfs.h"
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#define SW842_HASHTABLE8_BITS (10)
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#define SW842_HASHTABLE4_BITS (11)
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#define SW842_HASHTABLE2_BITS (10)
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/* By default, we allow compressing input buffers of any length, but we must
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* use the non-standard "short data" template so the decompressor can correctly
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* reproduce the uncompressed data buffer at the right length. However the
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* hardware 842 compressor will not recognize the "short data" template, and
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* will fail to decompress any compressed buffer containing it (I have no idea
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* why anyone would want to use software to compress and hardware to decompress
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* but that's beside the point). This parameter forces the compression
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* function to simply reject any input buffer that isn't a multiple of 8 bytes
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* long, instead of using the "short data" template, so that all compressed
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* buffers produced by this function will be decompressable by the 842 hardware
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* decompressor. Unless you have a specific need for that, leave this disabled
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* so that any length buffer can be compressed.
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*/
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static bool sw842_strict;
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module_param_named(strict, sw842_strict, bool, 0644);
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static u8 comp_ops[OPS_MAX][5] = { /* params size in bits */
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{ I8, N0, N0, N0, 0x19 }, /* 8 */
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{ I4, I4, N0, N0, 0x18 }, /* 18 */
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{ I4, I2, I2, N0, 0x17 }, /* 25 */
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{ I2, I2, I4, N0, 0x13 }, /* 25 */
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{ I2, I2, I2, I2, 0x12 }, /* 32 */
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{ I4, I2, D2, N0, 0x16 }, /* 33 */
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{ I4, D2, I2, N0, 0x15 }, /* 33 */
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{ I2, D2, I4, N0, 0x0e }, /* 33 */
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{ D2, I2, I4, N0, 0x09 }, /* 33 */
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{ I2, I2, I2, D2, 0x11 }, /* 40 */
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{ I2, I2, D2, I2, 0x10 }, /* 40 */
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{ I2, D2, I2, I2, 0x0d }, /* 40 */
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{ D2, I2, I2, I2, 0x08 }, /* 40 */
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{ I4, D4, N0, N0, 0x14 }, /* 41 */
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{ D4, I4, N0, N0, 0x04 }, /* 41 */
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{ I2, I2, D4, N0, 0x0f }, /* 48 */
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{ I2, D2, I2, D2, 0x0c }, /* 48 */
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{ I2, D4, I2, N0, 0x0b }, /* 48 */
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{ D2, I2, I2, D2, 0x07 }, /* 48 */
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{ D2, I2, D2, I2, 0x06 }, /* 48 */
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{ D4, I2, I2, N0, 0x03 }, /* 48 */
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{ I2, D2, D4, N0, 0x0a }, /* 56 */
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{ D2, I2, D4, N0, 0x05 }, /* 56 */
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{ D4, I2, D2, N0, 0x02 }, /* 56 */
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{ D4, D2, I2, N0, 0x01 }, /* 56 */
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{ D8, N0, N0, N0, 0x00 }, /* 64 */
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};
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struct sw842_hlist_node8 {
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struct hlist_node node;
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u64 data;
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u8 index;
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};
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struct sw842_hlist_node4 {
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struct hlist_node node;
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u32 data;
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u16 index;
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};
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struct sw842_hlist_node2 {
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struct hlist_node node;
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u16 data;
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u8 index;
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};
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#define INDEX_NOT_FOUND (-1)
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#define INDEX_NOT_CHECKED (-2)
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struct sw842_param {
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u8 *in;
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u8 *instart;
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u64 ilen;
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u8 *out;
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u64 olen;
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u8 bit;
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u64 data8[1];
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u32 data4[2];
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u16 data2[4];
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int index8[1];
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int index4[2];
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int index2[4];
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DECLARE_HASHTABLE(htable8, SW842_HASHTABLE8_BITS);
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DECLARE_HASHTABLE(htable4, SW842_HASHTABLE4_BITS);
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DECLARE_HASHTABLE(htable2, SW842_HASHTABLE2_BITS);
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struct sw842_hlist_node8 node8[1 << I8_BITS];
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struct sw842_hlist_node4 node4[1 << I4_BITS];
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struct sw842_hlist_node2 node2[1 << I2_BITS];
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};
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#define get_input_data(p, o, b) \
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be##b##_to_cpu(get_unaligned((__be##b *)((p)->in + (o))))
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#define init_hashtable_nodes(p, b) do { \
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int _i; \
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hash_init((p)->htable##b); \
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for (_i = 0; _i < ARRAY_SIZE((p)->node##b); _i++) { \
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(p)->node##b[_i].index = _i; \
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(p)->node##b[_i].data = 0; \
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INIT_HLIST_NODE(&(p)->node##b[_i].node); \
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} \
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} while (0)
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#define find_index(p, b, n) ({ \
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struct sw842_hlist_node##b *_n; \
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p->index##b[n] = INDEX_NOT_FOUND; \
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hash_for_each_possible(p->htable##b, _n, node, p->data##b[n]) { \
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if (p->data##b[n] == _n->data) { \
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p->index##b[n] = _n->index; \
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break; \
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} \
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} \
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p->index##b[n] >= 0; \
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})
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#define check_index(p, b, n) \
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((p)->index##b[n] == INDEX_NOT_CHECKED \
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? find_index(p, b, n) \
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: (p)->index##b[n] >= 0)
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#define replace_hash(p, b, i, d) do { \
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struct sw842_hlist_node##b *_n = &(p)->node##b[(i)+(d)]; \
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hash_del(&_n->node); \
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_n->data = (p)->data##b[d]; \
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pr_debug("add hash index%x %x pos %x data %lx\n", b, \
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(unsigned int)_n->index, \
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(unsigned int)((p)->in - (p)->instart), \
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(unsigned long)_n->data); \
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hash_add((p)->htable##b, &_n->node, _n->data); \
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} while (0)
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static u8 bmask[8] = { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe };
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static int add_bits(struct sw842_param *p, u64 d, u8 n);
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static int __split_add_bits(struct sw842_param *p, u64 d, u8 n, u8 s)
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{
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int ret;
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if (n <= s)
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return -EINVAL;
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ret = add_bits(p, d >> s, n - s);
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if (ret)
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return ret;
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return add_bits(p, d & GENMASK_ULL(s - 1, 0), s);
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}
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static int add_bits(struct sw842_param *p, u64 d, u8 n)
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{
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int b = p->bit, bits = b + n, s = round_up(bits, 8) - bits;
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u64 o;
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u8 *out = p->out;
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pr_debug("add %u bits %lx\n", (unsigned char)n, (unsigned long)d);
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if (n > 64)
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return -EINVAL;
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/* split this up if writing to > 8 bytes (i.e. n == 64 && p->bit > 0),
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* or if we're at the end of the output buffer and would write past end
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*/
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if (bits > 64)
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return __split_add_bits(p, d, n, 32);
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else if (p->olen < 8 && bits > 32 && bits <= 56)
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return __split_add_bits(p, d, n, 16);
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else if (p->olen < 4 && bits > 16 && bits <= 24)
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return __split_add_bits(p, d, n, 8);
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if (DIV_ROUND_UP(bits, 8) > p->olen)
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return -ENOSPC;
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o = *out & bmask[b];
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d <<= s;
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if (bits <= 8)
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*out = o | d;
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else if (bits <= 16)
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put_unaligned(cpu_to_be16(o << 8 | d), (__be16 *)out);
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else if (bits <= 24)
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put_unaligned(cpu_to_be32(o << 24 | d << 8), (__be32 *)out);
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else if (bits <= 32)
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put_unaligned(cpu_to_be32(o << 24 | d), (__be32 *)out);
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else if (bits <= 40)
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put_unaligned(cpu_to_be64(o << 56 | d << 24), (__be64 *)out);
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else if (bits <= 48)
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put_unaligned(cpu_to_be64(o << 56 | d << 16), (__be64 *)out);
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else if (bits <= 56)
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put_unaligned(cpu_to_be64(o << 56 | d << 8), (__be64 *)out);
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else
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put_unaligned(cpu_to_be64(o << 56 | d), (__be64 *)out);
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p->bit += n;
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if (p->bit > 7) {
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p->out += p->bit / 8;
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p->olen -= p->bit / 8;
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p->bit %= 8;
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}
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return 0;
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}
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static int add_template(struct sw842_param *p, u8 c)
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{
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int ret, i, b = 0;
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u8 *t = comp_ops[c];
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bool inv = false;
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if (c >= OPS_MAX)
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return -EINVAL;
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pr_debug("template %x\n", t[4]);
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ret = add_bits(p, t[4], OP_BITS);
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if (ret)
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return ret;
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for (i = 0; i < 4; i++) {
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pr_debug("op %x\n", t[i]);
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switch (t[i] & OP_AMOUNT) {
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case OP_AMOUNT_8:
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if (b)
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inv = true;
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else if (t[i] & OP_ACTION_INDEX)
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ret = add_bits(p, p->index8[0], I8_BITS);
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else if (t[i] & OP_ACTION_DATA)
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ret = add_bits(p, p->data8[0], 64);
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else
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inv = true;
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break;
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case OP_AMOUNT_4:
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if (b == 2 && t[i] & OP_ACTION_DATA)
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ret = add_bits(p, get_input_data(p, 2, 32), 32);
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else if (b != 0 && b != 4)
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inv = true;
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else if (t[i] & OP_ACTION_INDEX)
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ret = add_bits(p, p->index4[b >> 2], I4_BITS);
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else if (t[i] & OP_ACTION_DATA)
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ret = add_bits(p, p->data4[b >> 2], 32);
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else
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inv = true;
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break;
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case OP_AMOUNT_2:
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if (b != 0 && b != 2 && b != 4 && b != 6)
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inv = true;
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if (t[i] & OP_ACTION_INDEX)
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ret = add_bits(p, p->index2[b >> 1], I2_BITS);
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else if (t[i] & OP_ACTION_DATA)
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ret = add_bits(p, p->data2[b >> 1], 16);
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else
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inv = true;
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break;
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case OP_AMOUNT_0:
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inv = (b != 8) || !(t[i] & OP_ACTION_NOOP);
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break;
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default:
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inv = true;
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break;
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}
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if (ret)
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return ret;
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if (inv) {
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pr_err("Invalid templ %x op %d : %x %x %x %x\n",
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c, i, t[0], t[1], t[2], t[3]);
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return -EINVAL;
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}
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b += t[i] & OP_AMOUNT;
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}
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if (b != 8) {
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pr_err("Invalid template %x len %x : %x %x %x %x\n",
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c, b, t[0], t[1], t[2], t[3]);
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return -EINVAL;
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}
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if (sw842_template_counts)
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atomic_inc(&template_count[t[4]]);
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return 0;
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}
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static int add_repeat_template(struct sw842_param *p, u8 r)
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{
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int ret;
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/* repeat param is 0-based */
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if (!r || --r > REPEAT_BITS_MAX)
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return -EINVAL;
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ret = add_bits(p, OP_REPEAT, OP_BITS);
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if (ret)
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return ret;
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ret = add_bits(p, r, REPEAT_BITS);
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if (ret)
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return ret;
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if (sw842_template_counts)
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atomic_inc(&template_repeat_count);
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return 0;
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}
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static int add_short_data_template(struct sw842_param *p, u8 b)
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{
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int ret, i;
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if (!b || b > SHORT_DATA_BITS_MAX)
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return -EINVAL;
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ret = add_bits(p, OP_SHORT_DATA, OP_BITS);
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if (ret)
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return ret;
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ret = add_bits(p, b, SHORT_DATA_BITS);
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if (ret)
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return ret;
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for (i = 0; i < b; i++) {
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ret = add_bits(p, p->in[i], 8);
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if (ret)
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return ret;
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}
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if (sw842_template_counts)
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atomic_inc(&template_short_data_count);
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return 0;
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}
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static int add_zeros_template(struct sw842_param *p)
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{
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int ret = add_bits(p, OP_ZEROS, OP_BITS);
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if (ret)
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return ret;
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if (sw842_template_counts)
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atomic_inc(&template_zeros_count);
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return 0;
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}
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static int add_end_template(struct sw842_param *p)
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{
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int ret = add_bits(p, OP_END, OP_BITS);
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if (ret)
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return ret;
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if (sw842_template_counts)
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atomic_inc(&template_end_count);
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return 0;
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}
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static bool check_template(struct sw842_param *p, u8 c)
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{
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u8 *t = comp_ops[c];
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int i, match, b = 0;
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if (c >= OPS_MAX)
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return false;
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for (i = 0; i < 4; i++) {
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if (t[i] & OP_ACTION_INDEX) {
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if (t[i] & OP_AMOUNT_2)
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match = check_index(p, 2, b >> 1);
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else if (t[i] & OP_AMOUNT_4)
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match = check_index(p, 4, b >> 2);
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else if (t[i] & OP_AMOUNT_8)
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match = check_index(p, 8, 0);
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else
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return false;
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if (!match)
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return false;
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}
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b += t[i] & OP_AMOUNT;
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}
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return true;
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}
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static void get_next_data(struct sw842_param *p)
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{
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p->data8[0] = get_input_data(p, 0, 64);
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p->data4[0] = get_input_data(p, 0, 32);
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p->data4[1] = get_input_data(p, 4, 32);
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p->data2[0] = get_input_data(p, 0, 16);
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p->data2[1] = get_input_data(p, 2, 16);
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p->data2[2] = get_input_data(p, 4, 16);
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p->data2[3] = get_input_data(p, 6, 16);
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}
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/* update the hashtable entries.
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* only call this after finding/adding the current template
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* the dataN fields for the current 8 byte block must be already updated
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*/
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static void update_hashtables(struct sw842_param *p)
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{
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u64 pos = p->in - p->instart;
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u64 n8 = (pos >> 3) % (1 << I8_BITS);
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u64 n4 = (pos >> 2) % (1 << I4_BITS);
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u64 n2 = (pos >> 1) % (1 << I2_BITS);
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replace_hash(p, 8, n8, 0);
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replace_hash(p, 4, n4, 0);
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replace_hash(p, 4, n4, 1);
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replace_hash(p, 2, n2, 0);
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replace_hash(p, 2, n2, 1);
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replace_hash(p, 2, n2, 2);
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replace_hash(p, 2, n2, 3);
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}
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/* find the next template to use, and add it
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* the p->dataN fields must already be set for the current 8 byte block
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*/
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static int process_next(struct sw842_param *p)
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{
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int ret, i;
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p->index8[0] = INDEX_NOT_CHECKED;
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p->index4[0] = INDEX_NOT_CHECKED;
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p->index4[1] = INDEX_NOT_CHECKED;
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p->index2[0] = INDEX_NOT_CHECKED;
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p->index2[1] = INDEX_NOT_CHECKED;
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p->index2[2] = INDEX_NOT_CHECKED;
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p->index2[3] = INDEX_NOT_CHECKED;
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/* check up to OPS_MAX - 1; last op is our fallback */
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for (i = 0; i < OPS_MAX - 1; i++) {
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if (check_template(p, i))
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break;
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}
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ret = add_template(p, i);
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if (ret)
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return ret;
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return 0;
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}
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/**
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* sw842_compress
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*
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* Compress the uncompressed buffer of length @ilen at @in to the output buffer
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* @out, using no more than @olen bytes, using the 842 compression format.
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*
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* Returns: 0 on success, error on failure. The @olen parameter
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* will contain the number of output bytes written on success, or
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* 0 on error.
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*/
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int sw842_compress(const u8 *in, unsigned int ilen,
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u8 *out, unsigned int *olen, void *wmem)
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{
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struct sw842_param *p = (struct sw842_param *)wmem;
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int ret;
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u64 last, next, pad, total;
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u8 repeat_count = 0;
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u32 crc;
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BUILD_BUG_ON(sizeof(*p) > SW842_MEM_COMPRESS);
|
|
|
|
init_hashtable_nodes(p, 8);
|
|
init_hashtable_nodes(p, 4);
|
|
init_hashtable_nodes(p, 2);
|
|
|
|
p->in = (u8 *)in;
|
|
p->instart = p->in;
|
|
p->ilen = ilen;
|
|
p->out = out;
|
|
p->olen = *olen;
|
|
p->bit = 0;
|
|
|
|
total = p->olen;
|
|
|
|
*olen = 0;
|
|
|
|
/* if using strict mode, we can only compress a multiple of 8 */
|
|
if (sw842_strict && (ilen % 8)) {
|
|
pr_err("Using strict mode, can't compress len %d\n", ilen);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* let's compress at least 8 bytes, mkay? */
|
|
if (unlikely(ilen < 8))
|
|
goto skip_comp;
|
|
|
|
/* make initial 'last' different so we don't match the first time */
|
|
last = ~get_unaligned((u64 *)p->in);
|
|
|
|
while (p->ilen > 7) {
|
|
next = get_unaligned((u64 *)p->in);
|
|
|
|
/* must get the next data, as we need to update the hashtable
|
|
* entries with the new data every time
|
|
*/
|
|
get_next_data(p);
|
|
|
|
/* we don't care about endianness in last or next;
|
|
* we're just comparing 8 bytes to another 8 bytes,
|
|
* they're both the same endianness
|
|
*/
|
|
if (next == last) {
|
|
/* repeat count bits are 0-based, so we stop at +1 */
|
|
if (++repeat_count <= REPEAT_BITS_MAX)
|
|
goto repeat;
|
|
}
|
|
if (repeat_count) {
|
|
ret = add_repeat_template(p, repeat_count);
|
|
repeat_count = 0;
|
|
if (next == last) /* reached max repeat bits */
|
|
goto repeat;
|
|
}
|
|
|
|
if (next == 0)
|
|
ret = add_zeros_template(p);
|
|
else
|
|
ret = process_next(p);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
repeat:
|
|
last = next;
|
|
update_hashtables(p);
|
|
p->in += 8;
|
|
p->ilen -= 8;
|
|
}
|
|
|
|
if (repeat_count) {
|
|
ret = add_repeat_template(p, repeat_count);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
skip_comp:
|
|
if (p->ilen > 0) {
|
|
ret = add_short_data_template(p, p->ilen);
|
|
if (ret)
|
|
return ret;
|
|
|
|
p->in += p->ilen;
|
|
p->ilen = 0;
|
|
}
|
|
|
|
ret = add_end_template(p);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/*
|
|
* crc(0:31) is appended to target data starting with the next
|
|
* bit after End of stream template.
|
|
* nx842 calculates CRC for data in big-endian format. So doing
|
|
* same here so that sw842 decompression can be used for both
|
|
* compressed data.
|
|
*/
|
|
crc = crc32_be(0, in, ilen);
|
|
ret = add_bits(p, crc, CRC_BITS);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (p->bit) {
|
|
p->out++;
|
|
p->olen--;
|
|
p->bit = 0;
|
|
}
|
|
|
|
/* pad compressed length to multiple of 8 */
|
|
pad = (8 - ((total - p->olen) % 8)) % 8;
|
|
if (pad) {
|
|
if (pad > p->olen) /* we were so close! */
|
|
return -ENOSPC;
|
|
memset(p->out, 0, pad);
|
|
p->out += pad;
|
|
p->olen -= pad;
|
|
}
|
|
|
|
if (unlikely((total - p->olen) > UINT_MAX))
|
|
return -ENOSPC;
|
|
|
|
*olen = total - p->olen;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(sw842_compress);
|
|
|
|
static int __init sw842_init(void)
|
|
{
|
|
if (sw842_template_counts)
|
|
sw842_debugfs_create();
|
|
|
|
return 0;
|
|
}
|
|
module_init(sw842_init);
|
|
|
|
static void __exit sw842_exit(void)
|
|
{
|
|
if (sw842_template_counts)
|
|
sw842_debugfs_remove();
|
|
}
|
|
module_exit(sw842_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Software 842 Compressor");
|
|
MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
|