^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /* SPDX-License-Identifier: GPL-2.0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) #ifndef __842_H__
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) #define __842_H__
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) /* The 842 compressed format is made up of multiple blocks, each of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * which have the format:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * <template>[arg1][arg2][arg3][arg4]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) * where there are between 0 and 4 template args, depending on the specific
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * template operation. For normal operations, each arg is either a specific
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) * number of data bytes to add to the output buffer, or an index pointing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) * to a previously-written number of data bytes to copy to the output buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) * The template code is a 5-bit value. This code indicates what to do with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) * the following data. Template codes from 0 to 0x19 should use the template
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * table, the static "decomp_ops" table used in decompress. For each template
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * (table row), there are between 1 and 4 actions; each action corresponds to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * an arg following the template code bits. Each action is either a "data"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * type action, or a "index" type action, and each action results in 2, 4, or 8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * bytes being written to the output buffer. Each template (i.e. all actions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) * in the table row) will add up to 8 bytes being written to the output buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * Any row with less than 4 actions is padded with noop actions, indicated by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) * N0 (for which there is no corresponding arg in the compressed data buffer).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * "Data" actions, indicated in the table by D2, D4, and D8, mean that the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * corresponding arg is 2, 4, or 8 bytes, respectively, in the compressed data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * buffer should be copied directly to the output buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * "Index" actions, indicated in the table by I2, I4, and I8, mean the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) * corresponding arg is an index parameter that points to, respectively, a 2,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * 4, or 8 byte value already in the output buffer, that should be copied to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * the end of the output buffer. Essentially, the index points to a position
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * in a ring buffer that contains the last N bytes of output buffer data.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * The number of bits for each index's arg are: 8 bits for I2, 9 bits for I4,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * and 8 bits for I8. Since each index points to a 2, 4, or 8 byte section,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * this means that I2 can reference 512 bytes ((2^8 bits = 256) * 2 bytes), I4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * can reference 2048 bytes ((2^9 = 512) * 4 bytes), and I8 can reference 2048
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * bytes ((2^8 = 256) * 8 bytes). Think of it as a kind-of ring buffer for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * each of I2, I4, and I8 that are updated for each byte written to the output
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * buffer. In this implementation, the output buffer is directly used for each
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * index; there is no additional memory required. Note that the index is into
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * a ring buffer, not a sliding window; for example, if there have been 260
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * bytes written to the output buffer, an I2 index of 0 would index to byte 256
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * in the output buffer, while an I2 index of 16 would index to byte 16 in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) * output buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * There are also 3 special template codes; 0x1b for "repeat", 0x1c for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * "zeros", and 0x1e for "end". The "repeat" operation is followed by a 6 bit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) * arg N indicating how many times to repeat. The last 8 bytes written to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * output buffer are written again to the output buffer, N + 1 times. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * "zeros" operation, which has no arg bits, writes 8 zeros to the output
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * buffer. The "end" operation, which also has no arg bits, signals the end
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) * of the compressed data. There may be some number of padding (don't care,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * but usually 0) bits after the "end" operation bits, to fill the buffer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) * length to a specific byte multiple (usually a multiple of 8, 16, or 32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * bytes).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) * This software implementation also uses one of the undefined template values,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) * 0x1d as a special "short data" template code, to represent less than 8 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) * of uncompressed data. It is followed by a 3 bit arg N indicating how many
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) * data bytes will follow, and then N bytes of data, which should be copied to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) * the output buffer. This allows the software 842 compressor to accept input
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * buffers that are not an exact multiple of 8 bytes long. However, those
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) * compressed buffers containing this sw-only template will be rejected by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) * the 842 hardware decompressor, and must be decompressed with this software
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) * library. The 842 software compression module includes a parameter to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) * disable using this sw-only "short data" template, and instead simply
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) * reject any input buffer that is not a multiple of 8 bytes long.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * After all actions for each operation code are processed, another template
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) * code is in the next 5 bits. The decompression ends once the "end" template
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) * code is detected.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) #include <linux/bitops.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) #include <linux/crc32.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) #include <asm/unaligned.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) #include <linux/sw842.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) /* special templates */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) #define OP_REPEAT (0x1B)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) #define OP_ZEROS (0x1C)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) #define OP_END (0x1E)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) /* sw only template - this is not in the hw design; it's used only by this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) * software compressor and decompressor, to allow input buffers that aren't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) * a multiple of 8.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) #define OP_SHORT_DATA (0x1D)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) /* additional bits of each op param */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) #define OP_BITS (5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) #define REPEAT_BITS (6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) #define SHORT_DATA_BITS (3)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) #define I2_BITS (8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) #define I4_BITS (9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) #define I8_BITS (8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) #define CRC_BITS (32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) #define REPEAT_BITS_MAX (0x3f)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) #define SHORT_DATA_BITS_MAX (0x7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) /* Arbitrary values used to indicate action */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) #define OP_ACTION (0x70)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) #define OP_ACTION_INDEX (0x10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) #define OP_ACTION_DATA (0x20)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) #define OP_ACTION_NOOP (0x40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) #define OP_AMOUNT (0x0f)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) #define OP_AMOUNT_0 (0x00)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) #define OP_AMOUNT_2 (0x02)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) #define OP_AMOUNT_4 (0x04)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) #define OP_AMOUNT_8 (0x08)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) #define D2 (OP_ACTION_DATA | OP_AMOUNT_2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) #define D4 (OP_ACTION_DATA | OP_AMOUNT_4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) #define D8 (OP_ACTION_DATA | OP_AMOUNT_8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) #define I2 (OP_ACTION_INDEX | OP_AMOUNT_2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) #define I4 (OP_ACTION_INDEX | OP_AMOUNT_4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) #define I8 (OP_ACTION_INDEX | OP_AMOUNT_8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) #define N0 (OP_ACTION_NOOP | OP_AMOUNT_0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) /* the max of the regular templates - not including the special templates */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) #define OPS_MAX (0x1a)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) #endif
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
3 Commits
0 Branches
0 Tags