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1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 /* Try to choose an implementation variant via Kconfig */
4 #ifdef CONFIG_CRC32_SLICEBY8
5 # define CRC_LE_BITS 64
6 # define CRC_BE_BITS 64
7 #endif
8 #ifdef CONFIG_CRC32_SLICEBY4
9 # define CRC_LE_BITS 32
10 # define CRC_BE_BITS 32
11 #endif
12 #ifdef CONFIG_CRC32_SARWATE
13 # define CRC_LE_BITS 8
14 # define CRC_BE_BITS 8
15 #endif
16 #ifdef CONFIG_CRC32_BIT
17 # define CRC_LE_BITS 1
18 # define CRC_BE_BITS 1
19 #endif
20 
21 /*
22  * How many bits at a time to use.  Valid values are 1, 2, 4, 8, 32 and 64.
23  * For less performance-sensitive, use 4 or 8 to save table size.
24  * For larger systems choose same as CPU architecture as default.
25  * This works well on X86_64, SPARC64 systems. This may require some
26  * elaboration after experiments with other architectures.
27  */
28 #ifndef CRC_LE_BITS
29 #  ifdef CONFIG_64BIT
30 #  define CRC_LE_BITS 64
31 #  else
32 #  define CRC_LE_BITS 32
33 #  endif
34 #endif
35 #ifndef CRC_BE_BITS
36 #  ifdef CONFIG_64BIT
37 #  define CRC_BE_BITS 64
38 #  else
39 #  define CRC_BE_BITS 32
40 #  endif
41 #endif
42 
43 /*
44  * Little-endian CRC computation.  Used with serial bit streams sent
45  * lsbit-first.  Be sure to use cpu_to_le32() to append the computed CRC.
46  */
47 #if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \
48 	CRC_LE_BITS & CRC_LE_BITS-1
49 # error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
50 #endif
51 
52 /*
53  * Big-endian CRC computation.  Used with serial bit streams sent
54  * msbit-first.  Be sure to use cpu_to_be32() to append the computed CRC.
55  */
56 #if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \
57 	CRC_BE_BITS & CRC_BE_BITS-1
58 # error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
59 #endif
60