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  • /*
     * Copyright (C) 2014 Marek Vasut <marex@denx.de>
     *
     * Command for en/de-crypting block of memory with AES-128-CBC cipher.
     *
     * SPDX-License-Identifier:	GPL-2.0+
     */
    
    #include <common.h>
    #include <command.h>
    #include <environment.h>
    #include <aes.h>
    #include <malloc.h>
    #include <asm/byteorder.h>
    #include <linux/compiler.h>
    
    DECLARE_GLOBAL_DATA_PTR;
    
    /**
     * do_aes() - Handle the "aes" command-line command
     * @cmdtp:	Command data struct pointer
     * @flag:	Command flag
     * @argc:	Command-line argument count
     * @argv:	Array of command-line arguments
     *
     * Returns zero on success, CMD_RET_USAGE in case of misuse and negative
     * on error.
     */
    static int do_aes(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
    {
    	uint32_t key_addr, src_addr, dst_addr, len;
    	uint8_t *key_ptr, *src_ptr, *dst_ptr;
    	uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
    	uint32_t aes_blocks;
    	int enc;
    
    	if (argc != 6)
    		return CMD_RET_USAGE;
    
    	if (!strncmp(argv[1], "enc", 3))
    		enc = 1;
    	else if (!strncmp(argv[1], "dec", 3))
    		enc = 0;
    	else
    		return CMD_RET_USAGE;
    
    	key_addr = simple_strtoul(argv[2], NULL, 16);
    	src_addr = simple_strtoul(argv[3], NULL, 16);
    	dst_addr = simple_strtoul(argv[4], NULL, 16);
    	len = simple_strtoul(argv[5], NULL, 16);
    
    	key_ptr = (uint8_t *)key_addr;
    	src_ptr = (uint8_t *)src_addr;
    	dst_ptr = (uint8_t *)dst_addr;
    
    	/* First we expand the key. */
    	aes_expand_key(key_ptr, key_exp);
    
    	/* Calculate the number of AES blocks to encrypt. */
    	aes_blocks = DIV_ROUND_UP(len, AES_KEY_LENGTH);
    
    	if (enc)
    		aes_cbc_encrypt_blocks(key_exp, src_ptr, dst_ptr, aes_blocks);
    	else
    		aes_cbc_decrypt_blocks(key_exp, src_ptr, dst_ptr, aes_blocks);
    
    	return 0;
    }
    
    /***************************************************/
    #ifdef CONFIG_SYS_LONGHELP
    static char aes_help_text[] =
    	"enc key src dst len - Encrypt block of data $len bytes long\n"
    	"                          at address $src using a key at address\n"
    	"                          $key and store the result at address\n"
    	"                          $dst. The $len size must be multiple of\n"
    	"                          16 bytes and $key must be 16 bytes long.\n"
    	"aes dec key src dst len - Decrypt block of data $len bytes long\n"
    	"                          at address $src using a key at address\n"
    	"                          $key and store the result at address\n"
    	"                          $dst. The $len size must be multiple of\n"
    	"                          16 bytes and $key must be 16 bytes long.";
    #endif
    
    U_BOOT_CMD(
    	aes, 6, 1, do_aes,
    	"AES 128 CBC encryption",
    	aes_help_text
    );