drivers/crypto/atmel-ecc.h

   1 /*
   2  * Copyright (c) 2017, Microchip Technology Inc.
   3  * Author: Tudor Ambarus <tudor.ambarus@microchip.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program.  If not, see <http://www.gnu.org/licenses/>.
  16  *
  17  */
  18
  19 #ifndef __ATMEL_ECC_H__
  20 #define __ATMEL_ECC_H__
  21
  22 #define ATMEL_ECC_PRIORITY              300
  23
  24 #define COMMAND                         0x03 /* packet function */
  25 #define SLEEP_TOKEN                     0x01
  26 #define WAKE_TOKEN_MAX_SIZE             8
  27
  28 /* Definitions of Data and Command sizes */
  29 #define WORD_ADDR_SIZE                  1
  30 #define COUNT_SIZE                      1
  31 #define CRC_SIZE                        2
  32 #define CMD_OVERHEAD_SIZE               (COUNT_SIZE + CRC_SIZE)
  33
  34 /* size in bytes of the n prime */
  35 #define ATMEL_ECC_NIST_P256_N_SIZE      32
  36 #define ATMEL_ECC_PUBKEY_SIZE           (2 * ATMEL_ECC_NIST_P256_N_SIZE)
  37
  38 #define STATUS_RSP_SIZE                 4
  39 #define ECDH_RSP_SIZE                   (32 + CMD_OVERHEAD_SIZE)
  40 #define GENKEY_RSP_SIZE                 (ATMEL_ECC_PUBKEY_SIZE + \
  41                                          CMD_OVERHEAD_SIZE)
  42 #define READ_RSP_SIZE                   (4 + CMD_OVERHEAD_SIZE)
  43 #define MAX_RSP_SIZE                    GENKEY_RSP_SIZE
  44
  45 /**
  46  * atmel_ecc_cmd - structure used for communicating with the device.
  47  * @word_addr: indicates the function of the packet sent to the device. This
  48  *             byte should have a value of COMMAND for normal operation.
  49  * @count    : number of bytes to be transferred to (or from) the device.
  50  * @opcode   : the command code.
  51  * @param1   : the first parameter; always present.
  52  * @param2   : the second parameter; always present.
  53  * @data     : optional remaining input data. Includes a 2-byte CRC.
  54  * @rxsize   : size of the data received from i2c client.
  55  * @msecs    : command execution time in milliseconds
  56  */
  57 struct atmel_ecc_cmd {
  58         u8 word_addr;
  59         u8 count;
  60         u8 opcode;
  61         u8 param1;
  62         u16 param2;
  63         u8 data[MAX_RSP_SIZE];
  64         u8 msecs;
  65         u16 rxsize;
  66 } __packed;
  67
  68 /* Status/Error codes */
  69 #define STATUS_SIZE                     0x04
  70 #define STATUS_NOERR                    0x00
  71 #define STATUS_WAKE_SUCCESSFUL          0x11
  72
  73 static const struct {
  74         u8 value;
  75         const char *error_text;
  76 } error_list[] = {
  77         { 0x01, "CheckMac or Verify miscompare" },
  78         { 0x03, "Parse Error" },
  79         { 0x05, "ECC Fault" },
  80         { 0x0F, "Execution Error" },
  81         { 0xEE, "Watchdog about to expire" },
  82         { 0xFF, "CRC or other communication error" },
  83 };
  84
  85 /* Definitions for eeprom organization */
  86 #define CONFIG_ZONE                     0
  87
  88 /* Definitions for Indexes common to all commands */
  89 #define RSP_DATA_IDX                    1 /* buffer index of data in response */
  90 #define DATA_SLOT_2                     2 /* used for ECDH private key */
  91
  92 /* Definitions for the device lock state */
  93 #define DEVICE_LOCK_ADDR                0x15
  94 #define LOCK_VALUE_IDX                  (RSP_DATA_IDX + 2)
  95 #define LOCK_CONFIG_IDX                 (RSP_DATA_IDX + 3)
  96
  97 /*
  98  * Wake High delay to data communication (microseconds). SDA should be stable
  99  * high for this entire duration.
 100  */
 101 #define TWHI_MIN                        1500
 102 #define TWHI_MAX                        1550
 103
 104 /* Wake Low duration */
 105 #define TWLO_USEC                       60
 106
 107 /* Command execution time (milliseconds) */
 108 #define MAX_EXEC_TIME_ECDH              58
 109 #define MAX_EXEC_TIME_GENKEY            115
 110 #define MAX_EXEC_TIME_READ              1
 111
 112 /* Command opcode */
 113 #define OPCODE_ECDH                     0x43
 114 #define OPCODE_GENKEY                   0x40
 115 #define OPCODE_READ                     0x02
 116
 117 /* Definitions for the READ Command */
 118 #define READ_COUNT                      7
 119
 120 /* Definitions for the GenKey Command */
 121 #define GENKEY_COUNT                    7
 122 #define GENKEY_MODE_PRIVATE             0x04
 123
 124 /* Definitions for the ECDH Command */
 125 #define ECDH_COUNT                      71
 126 #define ECDH_PREFIX_MODE                0x00
 127
 128 #endif /* __ATMEL_ECC_H__ */