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 void atmel_i2c_flush_queue(void); 177 178 int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd); 179 180 void atmel_i2c_init_read_cmd(struct atmel_i2c_cmd *cmd); 181 void atmel_i2c_init_random_cmd(struct atmel_i2c_cmd *cmd); 182 void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid); 183 int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd, 184 struct scatterlist *pubkey); 185 186 #endif /* __ATMEL_I2C_H__ */ 187