drivers/crypto/atmel-i2c.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (c) 2017, Microchip Technology Inc.
   4  * Author: Tudor Ambarus
   5  */
   6
   7 #ifndef __ATMEL_I2C_H__
   8 #define __ATMEL_I2C_H__
   9
  10 #include <linux/hw_random.h>
  11 #include <linux/types.h>
  12
  13 #define ATMEL_ECC_PRIORITY              300
  14
  15 #define COMMAND                         0x03 /* packet function */
  16 #define SLEEP_TOKEN                     0x01
  17 #define WAKE_TOKEN_MAX_SIZE             8
  18
  19 /* Definitions of Data and Command sizes */
  20 #define WORD_ADDR_SIZE                  1
  21 #define COUNT_SIZE                      1
  22 #define CRC_SIZE                        2
  23 #define CMD_OVERHEAD_SIZE               (COUNT_SIZE + CRC_SIZE)
  24
  25 /* size in bytes of the n prime */
  26 #define ATMEL_ECC_NIST_P256_N_SIZE      32
  27 #define ATMEL_ECC_PUBKEY_SIZE           (2 * ATMEL_ECC_NIST_P256_N_SIZE)
  28
  29 #define STATUS_RSP_SIZE                 4
  30 #define ECDH_RSP_SIZE                   (32 + CMD_OVERHEAD_SIZE)
  31 #define GENKEY_RSP_SIZE                 (ATMEL_ECC_PUBKEY_SIZE + \
  32                                          CMD_OVERHEAD_SIZE)
  33 #define READ_RSP_SIZE                   (4 + CMD_OVERHEAD_SIZE)
  34 #define RANDOM_RSP_SIZE                 (32 + CMD_OVERHEAD_SIZE)
  35 #define MAX_RSP_SIZE                    GENKEY_RSP_SIZE
  36
  37 /**
  38  * atmel_i2c_cmd - structure used for communicating with the device.
  39  * @word_addr: indicates the function of the packet sent to the device. This
  40  *             byte should have a value of COMMAND for normal operation.
  41  * @count    : number of bytes to be transferred to (or from) the device.
  42  * @opcode   : the command code.
  43  * @param1   : the first parameter; always present.
  44  * @param2   : the second parameter; always present.
  45  * @data     : optional remaining input data. Includes a 2-byte CRC.
  46  * @rxsize   : size of the data received from i2c client.
  47  * @msecs    : command execution time in milliseconds
  48  */
  49 struct atmel_i2c_cmd {
  50         u8 word_addr;
  51         u8 count;
  52         u8 opcode;
  53         u8 param1;
  54         __le16 param2;
  55         u8 data[MAX_RSP_SIZE];
  56         u8 msecs;
  57         u16 rxsize;
  58 } __packed;
  59
  60 /* Status/Error codes */
  61 #define STATUS_SIZE                     0x04
  62 #define STATUS_NOERR                    0x00
  63 #define STATUS_WAKE_SUCCESSFUL          0x11
  64
  65 /* Definitions for eeprom organization */
  66 #define CONFIGURATION_ZONE              0
  67 #define OTP_ZONE                        1
  68
  69 /* Definitions for eeprom zone sizes */
  70 #define OTP_ZONE_SIZE                   64
  71
  72 /* Definitions for Indexes common to all commands */
  73 #define RSP_DATA_IDX                    1 /* buffer index of data in response */
  74 #define DATA_SLOT_2                     2 /* used for ECDH private key */
  75
  76 /* Definitions for the device lock state */
  77 #define DEVICE_LOCK_ADDR                0x15
  78 #define LOCK_VALUE_IDX                  (RSP_DATA_IDX + 2)
  79 #define LOCK_CONFIG_IDX                 (RSP_DATA_IDX + 3)
  80
  81 /*
  82  * Wake High delay to data communication (microseconds). SDA should be stable
  83  * high for this entire duration.
  84  */
  85 #define TWHI_MIN                        1500
  86 #define TWHI_MAX                        1550
  87
  88 /* Wake Low duration */
  89 #define TWLO_USEC                       60
  90
  91 /* Command execution time (milliseconds) */
  92 #define MAX_EXEC_TIME_ECDH              58
  93 #define MAX_EXEC_TIME_GENKEY            115
  94 #define MAX_EXEC_TIME_READ              1
  95 #define MAX_EXEC_TIME_RANDOM            50
  96
  97 /* Command opcode */
  98 #define OPCODE_ECDH                     0x43
  99 #define OPCODE_GENKEY                   0x40
 100 #define OPCODE_READ                     0x02
 101 #define OPCODE_RANDOM                   0x1b
 102
 103 /* Definitions for the READ Command */
 104 #define READ_COUNT                      7
 105
 106 /* Definitions for the RANDOM Command */
 107 #define RANDOM_COUNT                    7
 108
 109 /* Definitions for the GenKey Command */
 110 #define GENKEY_COUNT                    7
 111 #define GENKEY_MODE_PRIVATE             0x04
 112
 113 /* Definitions for the ECDH Command */
 114 #define ECDH_COUNT                      71
 115 #define ECDH_PREFIX_MODE                0x00
 116
 117 /* Used for binding tfm objects to i2c clients. */
 118 struct atmel_ecc_driver_data {
 119         struct list_head i2c_client_list;
 120         spinlock_t i2c_list_lock;
 121 } ____cacheline_aligned;
 122
 123 /**
 124  * atmel_i2c_client_priv - i2c_client private data
 125  * @client              : pointer to i2c client device
 126  * @i2c_client_list_node: part of i2c_client_list
 127  * @lock                : lock for sending i2c commands
 128  * @wake_token          : wake token array of zeros
 129  * @wake_token_sz       : size in bytes of the wake_token
 130  * @tfm_count           : number of active crypto transformations on i2c client
 131  * @hwrng               : hold the hardware generated rng
 132  *
 133  * Reads and writes from/to the i2c client are sequential. The first byte
 134  * transmitted to the device is treated as the byte size. Any attempt to send
 135  * more than this number of bytes will cause the device to not ACK those bytes.
 136  * After the host writes a single command byte to the input buffer, reads are
 137  * prohibited until after the device completes command execution. Use a mutex
 138  * when sending i2c commands.
 139  */
 140 struct atmel_i2c_client_priv {
 141         struct i2c_client *client;
 142         struct list_head i2c_client_list_node;
 143         struct mutex lock;
 144         u8 wake_token[WAKE_TOKEN_MAX_SIZE];
 145         size_t wake_token_sz;
 146         atomic_t tfm_count ____cacheline_aligned;
 147         struct hwrng hwrng;
 148 };
 149
 150 /**
 151  * atmel_i2c_work_data - data structure representing the work
 152  * @ctx : transformation context.
 153  * @cbk : pointer to a callback function to be invoked upon completion of this
 154  *        request. This has the form:
 155  *        callback(struct atmel_i2c_work_data *work_data, void *areq, u8 status)
 156  *        where:
 157  *        @work_data: data structure representing the work
 158  *        @areq     : optional pointer to an argument passed with the original
 159  *                    request.
 160  *        @status   : status returned from the i2c client device or i2c error.
 161  * @areq: optional pointer to a user argument for use at callback time.
 162  * @work: describes the task to be executed.
 163  * @cmd : structure used for communicating with the device.
 164  */
 165 struct atmel_i2c_work_data {
 166         void *ctx;
 167         struct i2c_client *client;
 168         void (*cbk)(struct atmel_i2c_work_data *work_data, void *areq,
 169                     int status);
 170         void *areq;
 171         struct work_struct work;
 172         struct atmel_i2c_cmd cmd;
 173 };
 174
 175 int atmel_i2c_probe(struct i2c_client *client);
 176
 177 void atmel_i2c_enqueue(struct atmel_i2c_work_data *work_data,
 178                        void (*cbk)(struct atmel_i2c_work_data *work_data,
 179                                    void *areq, int status),
 180                        void *areq);
 181 void atmel_i2c_flush_queue(void);
 182
 183 int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd);
 184
 185 void atmel_i2c_init_read_config_cmd(struct atmel_i2c_cmd *cmd);
 186 int atmel_i2c_init_read_otp_cmd(struct atmel_i2c_cmd *cmd, u16 addr);
 187 void atmel_i2c_init_random_cmd(struct atmel_i2c_cmd *cmd);
 188 void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid);
 189 int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd,
 190                             struct scatterlist *pubkey);
 191
 192 #endif /* __ATMEL_I2C_H__ */