LXR linux/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 */
  49struct 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. */
 114struct 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 */
 135struct 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 */
 160struct 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
 170int atmel_i2c_probe(struct i2c_client *client, const struct i2c_device_id *id);
 171
 172void 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
 177int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd);
 178
 179void atmel_i2c_init_read_cmd(struct atmel_i2c_cmd *cmd);
 180void atmel_i2c_init_random_cmd(struct atmel_i2c_cmd *cmd);
 181void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid);
 182int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd,
 183                            struct scatterlist *pubkey);
 184
 185#endif /* __ATMEL_I2C_H__ */
 186