162306a36Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0 262306a36Sopenharmony_ci#include <linux/io.h> 362306a36Sopenharmony_ci#include <linux/export.h> 462306a36Sopenharmony_ci 562306a36Sopenharmony_ci/** 662306a36Sopenharmony_ci * check_signature - find BIOS signatures 762306a36Sopenharmony_ci * @io_addr: mmio address to check 862306a36Sopenharmony_ci * @signature: signature block 962306a36Sopenharmony_ci * @length: length of signature 1062306a36Sopenharmony_ci * 1162306a36Sopenharmony_ci * Perform a signature comparison with the mmio address io_addr. This 1262306a36Sopenharmony_ci * address should have been obtained by ioremap. 1362306a36Sopenharmony_ci * Returns 1 on a match. 1462306a36Sopenharmony_ci */ 1562306a36Sopenharmony_ci 1662306a36Sopenharmony_ciint check_signature(const volatile void __iomem *io_addr, 1762306a36Sopenharmony_ci const unsigned char *signature, int length) 1862306a36Sopenharmony_ci{ 1962306a36Sopenharmony_ci while (length--) { 2062306a36Sopenharmony_ci if (readb(io_addr) != *signature) 2162306a36Sopenharmony_ci return 0; 2262306a36Sopenharmony_ci io_addr++; 2362306a36Sopenharmony_ci signature++; 2462306a36Sopenharmony_ci } 2562306a36Sopenharmony_ci return 1; 2662306a36Sopenharmony_ci} 2762306a36Sopenharmony_ciEXPORT_SYMBOL(check_signature); 28