VisionFive2 Linux kernel

feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  1) // SPDX-License-Identifier: GPL-2.0
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  2) /*
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  3)  * Generate lookup table for the table-driven CRC64 calculation.
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  4)  *
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  5)  * gen_crc64table is executed in kernel build time and generates
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  6)  * lib/crc64table.h. This header is included by lib/crc64.c for
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  7)  * the table-driven CRC64 calculation.
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  8)  *
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700  9)  * See lib/crc64.c for more information about which specification
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 10)  * and polynomial arithmetic that gen_crc64table.c follows to
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 11)  * generate the lookup table.
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 12)  *
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 13)  * Copyright 2018 SUSE Linux.
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 14)  *   Author: Coly Li <colyli@suse.de>
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 15)  */
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 16) #include <inttypes.h>
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 17) #include <stdio.h>
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 18) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 19) #define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 20) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 21) static uint64_t crc64_table[256] = {0};
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 22) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 23) static void generate_crc64_table(void)
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 24) {
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 25) 	uint64_t i, j, c, crc;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 26) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 27) 	for (i = 0; i < 256; i++) {
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 28) 		crc = 0;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 29) 		c = i << 56;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 30) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 31) 		for (j = 0; j < 8; j++) {
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 32) 			if ((crc ^ c) & 0x8000000000000000ULL)
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 33) 				crc = (crc << 1) ^ CRC64_ECMA182_POLY;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 34) 			else
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 35) 				crc <<= 1;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 36) 			c <<= 1;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 37) 		}
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 38) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 39) 		crc64_table[i] = crc;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 40) 	}
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 41) }
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 42) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 43) static void print_crc64_table(void)
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 44) {
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 45) 	int i;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 46) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 47) 	printf("/* this file is generated - do not edit */\n\n");
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 48) 	printf("#include <linux/types.h>\n");
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 49) 	printf("#include <linux/cache.h>\n\n");
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 50) 	printf("static const u64 ____cacheline_aligned crc64table[256] = {\n");
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 51) 	for (i = 0; i < 256; i++) {
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 52) 		printf("\t0x%016" PRIx64 "ULL", crc64_table[i]);
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 53) 		if (i & 0x1)
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 54) 			printf(",\n");
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 55) 		else
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 56) 			printf(", ");
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 57) 	}
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 58) 	printf("};\n");
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 59) }
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 60) 
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 61) int main(int argc, char *argv[])
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 62) {
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 63) 	generate_crc64_table();
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 64) 	print_crc64_table();
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 65) 	return 0;
feba04fd2cf8f (Coly Li 2018-08-21 21:57:11 -0700 66) }