drivers/crypto/atmel-i2c.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (c) 2017, Microchip Technology Inc.
   4  * Author: Tudor Ambarus <tudor.ambarus@microchip.com>
   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 CONFIG_ZONE                     0
  67
  68 /* Definitions for Indexes common to all commands */
  69 #define RSP_DATA_IDX                    1 /* buffer index of data in response */
  70 #define DATA_SLOT_2                     2 /* used for ECDH private key */
  71
  72 /* Definitions for the device lock state */
  73 #define DEVICE_LOCK_ADDR                0x15
  74 #define LOCK_VALUE_IDX                  (RSP_DATA_IDX + 2)
  75 #define LOCK_CONFIG_IDX                 (RSP_DATA_IDX + 3)
  76
  77 /*
  78  * Wake High delay to data communication (microseconds). SDA should be stable
  79  * high for this entire duration.
  80  */
  81 #define TWHI_MIN                        1500
  82 #define TWHI_MAX                        1550
  83
  84 /* Wake Low duration */
  85 #define TWLO_USEC                       60
  86
  87 /* Command execution time (milliseconds) */
  88 #define MAX_EXEC_TIME_ECDH              58
  89 #define MAX_EXEC_TIME_GENKEY            115
  90 #define MAX_EXEC_TIME_READ              1
  91 #define MAX_EXEC_TIME_RANDOM            50
  92
  93 /* Command opcode */
  94 #define OPCODE_ECDH                     0x43
  95 #define OPCODE_GENKEY                   0x40
  96 #define OPCODE_READ                     0x02
  97 #define OPCODE_RANDOM                   0x1b
  98
  99 /* Definitions for the READ Command */
 100 #define READ_COUNT                      7
 101
 102 /* Definitions for the RANDOM Command */
 103 #define RANDOM_COUNT                    7
 104
 105 /* Definitions for the GenKey Command */
 106 #define GENKEY_COUNT                    7
 107 #define GENKEY_MODE_PRIVATE             0x04
 108
 109 /* Definitions for the ECDH Command */
 110 #define ECDH_COUNT                      71
 111 #define ECDH_PREFIX_MODE                0x00
 112
 113 /* Used for binding tfm objects to i2c clients. */
 114 struct atmel_ecc_driver_data {
 115         struct list_head i2c_client_list;
 116         spinlock_t i2c_list_lock;
 117 } ____cacheline_aligned;
 118
 119 /**
 120  * atmel_i2c_client_priv - i2c_client private data
 121  * @client              : pointer to i2c client device
 122  * @i2c_client_list_node: part of i2c_client_list
 123  * @lock                : lock for sending i2c commands
 124  * @wake_token          : wake token array of zeros
 125  * @wake_token_sz       : size in bytes of the wake_token
 126  * @tfm_count           : number of active crypto transformations on i2c client
 127  *
 128  * Reads and writes from/to the i2c client are sequential. The first byte
 129  * transmitted to the device is treated as the byte size. Any attempt to send
 130  * more than this number of bytes will cause the device to not ACK those bytes.
 131  * After the host writes a single command byte to the input buffer, reads are
 132  * prohibited until after the device completes command execution. Use a mutex
 133  * when sending i2c commands.
 134  */
 135 struct atmel_i2c_client_priv {
 136         struct i2c_client *client;
 137         struct list_head i2c_client_list_node;
 138         struct mutex lock;
 139         u8 wake_token[WAKE_TOKEN_MAX_SIZE];
 140         size_t wake_token_sz;
 141         atomic_t tfm_count ____cacheline_aligned;
 142         struct hwrng hwrng;
 143 };
 144
 145 /**
 146  * atmel_i2c_work_data - data structure representing the work
 147  * @ctx : transformation context.
 148  * @cbk : pointer to a callback function to be invoked upon completion of this
 149  *        request. This has the form:
 150  *        callback(struct atmel_i2c_work_data *work_data, void *areq, u8 status)
 151  *        where:
 152  *        @work_data: data structure representing the work
 153  *        @areq     : optional pointer to an argument passed with the original
 154  *                    request.
 155  *        @status   : status returned from the i2c client device or i2c error.
 156  * @areq: optional pointer to a user argument for use at callback time.
 157  * @work: describes the task to be executed.
 158  * @cmd : structure used for communicating with the device.
 159  */
 160 struct atmel_i2c_work_data {
 161         void *ctx;
 162         struct i2c_client *client;
 163         void (*cbk)(struct atmel_i2c_work_data *work_data, void *areq,
 164                     int status);
 165         void *areq;
 166         struct work_struct work;
 167         struct atmel_i2c_cmd cmd;
 168 };
 169
 170 int atmel_i2c_probe(struct i2c_client *client, const struct i2c_device_id *id);
 171
 172 void atmel_i2c_enqueue(struct atmel_i2c_work_data *work_data,
 173                        void (*cbk)(struct atmel_i2c_work_data *work_data,
 174                                    void *areq, int status),
 175                        void *areq);
 176
 177 int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd);
 178
 179 void atmel_i2c_init_read_cmd(struct atmel_i2c_cmd *cmd);
 180 void atmel_i2c_init_random_cmd(struct atmel_i2c_cmd *cmd);
 181 void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid);
 182 int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd,
 183                             struct scatterlist *pubkey);
 184
 185 #endif /* __ATMEL_I2C_H__ */