diff options
| author | Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> | 2018-09-26 15:54:31 +0200 |
|---|---|---|
| committer | Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> | 2018-09-26 15:54:31 +0200 |
| commit | aaccf3c97418f169afdbb5855e9cbcbda34e90fd (patch) | |
| tree | 5d4207e67958bdbc23288cf30178692f5534e1a0 /lib/gen_crc64table.c | |
| parent | f39684524b391c5a7ed0ac44db4fec3357af1c5d (diff) | |
| parent | 6bf4ca7fbc85d80446ac01c0d1d77db4d91a6d84 (diff) | |
Merge tag 'v4.19-rc5' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next
Sync with upstream (which now contains fbdev-v4.19 changes) to
prepare a base for fbdev-v4.20 changes.
Diffstat (limited to 'lib/gen_crc64table.c')
| -rw-r--r-- | lib/gen_crc64table.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/lib/gen_crc64table.c b/lib/gen_crc64table.c new file mode 100644 index 000000000000..9011926e4162 --- /dev/null +++ b/lib/gen_crc64table.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generate lookup table for the table-driven CRC64 calculation. + * + * gen_crc64table is executed in kernel build time and generates + * lib/crc64table.h. This header is included by lib/crc64.c for + * the table-driven CRC64 calculation. + * + * See lib/crc64.c for more information about which specification + * and polynomial arithmetic that gen_crc64table.c follows to + * generate the lookup table. + * + * Copyright 2018 SUSE Linux. + * Author: Coly Li <colyli@suse.de> + */ +#include <inttypes.h> +#include <stdio.h> + +#include <linux/swab.h> + +#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL + +static uint64_t crc64_table[256] = {0}; + +static void generate_crc64_table(void) +{ + uint64_t i, j, c, crc; + + for (i = 0; i < 256; i++) { + crc = 0; + c = i << 56; + + for (j = 0; j < 8; j++) { + if ((crc ^ c) & 0x8000000000000000ULL) + crc = (crc << 1) ^ CRC64_ECMA182_POLY; + else + crc <<= 1; + c <<= 1; + } + + crc64_table[i] = crc; + } +} + +static void print_crc64_table(void) +{ + int i; + + printf("/* this file is generated - do not edit */\n\n"); + printf("#include <linux/types.h>\n"); + printf("#include <linux/cache.h>\n\n"); + printf("static const u64 ____cacheline_aligned crc64table[256] = {\n"); + for (i = 0; i < 256; i++) { + printf("\t0x%016" PRIx64 "ULL", crc64_table[i]); + if (i & 0x1) + printf(",\n"); + else + printf(", "); + } + printf("};\n"); +} + +int main(int argc, char *argv[]) +{ + generate_crc64_table(); + print_crc64_table(); + return 0; +} |
