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__ */ 193