1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Copyright (c) 2017, Microchip Technology Inc.
4 * Author: Tudor Ambarus <tudor.ambarus@microchip.com>
7 #ifndef __ATMEL_I2C_H__
8 #define __ATMEL_I2C_H__
10 #include <linux/hw_random.h>
11 #include <linux/types.h>
13 #define ATMEL_ECC_PRIORITY 300
15 #define COMMAND 0x03 /* packet function */
16 #define SLEEP_TOKEN 0x01
17 #define WAKE_TOKEN_MAX_SIZE 8
19 /* Definitions of Data and Command sizes */
20 #define WORD_ADDR_SIZE 1
23 #define CMD_OVERHEAD_SIZE (COUNT_SIZE + CRC_SIZE)
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)
29 #define STATUS_RSP_SIZE 4
30 #define ECDH_RSP_SIZE (32 + CMD_OVERHEAD_SIZE)
31 #define GENKEY_RSP_SIZE (ATMEL_ECC_PUBKEY_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
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
49 struct atmel_i2c_cmd {
55 u8 data[MAX_RSP_SIZE];
60 /* Status/Error codes */
61 #define STATUS_SIZE 0x04
62 #define STATUS_NOERR 0x00
63 #define STATUS_WAKE_SUCCESSFUL 0x11
67 const char *error_text;
69 { 0x01, "CheckMac or Verify miscompare" },
70 { 0x03, "Parse Error" },
71 { 0x05, "ECC Fault" },
72 { 0x0F, "Execution Error" },
73 { 0xEE, "Watchdog about to expire" },
74 { 0xFF, "CRC or other communication error" },
77 /* Definitions for eeprom organization */
80 /* Definitions for Indexes common to all commands */
81 #define RSP_DATA_IDX 1 /* buffer index of data in response */
82 #define DATA_SLOT_2 2 /* used for ECDH private key */
84 /* Definitions for the device lock state */
85 #define DEVICE_LOCK_ADDR 0x15
86 #define LOCK_VALUE_IDX (RSP_DATA_IDX + 2)
87 #define LOCK_CONFIG_IDX (RSP_DATA_IDX + 3)
90 * Wake High delay to data communication (microseconds). SDA should be stable
91 * high for this entire duration.
96 /* Wake Low duration */
99 /* Command execution time (milliseconds) */
100 #define MAX_EXEC_TIME_ECDH 58
101 #define MAX_EXEC_TIME_GENKEY 115
102 #define MAX_EXEC_TIME_READ 1
103 #define MAX_EXEC_TIME_RANDOM 50
106 #define OPCODE_ECDH 0x43
107 #define OPCODE_GENKEY 0x40
108 #define OPCODE_READ 0x02
109 #define OPCODE_RANDOM 0x1b
111 /* Definitions for the READ Command */
114 /* Definitions for the RANDOM Command */
115 #define RANDOM_COUNT 7
117 /* Definitions for the GenKey Command */
118 #define GENKEY_COUNT 7
119 #define GENKEY_MODE_PRIVATE 0x04
121 /* Definitions for the ECDH Command */
122 #define ECDH_COUNT 71
123 #define ECDH_PREFIX_MODE 0x00
125 /* Used for binding tfm objects to i2c clients. */
126 struct atmel_ecc_driver_data {
127 struct list_head i2c_client_list;
128 spinlock_t i2c_list_lock;
129 } ____cacheline_aligned;
132 * atmel_i2c_client_priv - i2c_client private data
133 * @client : pointer to i2c client device
134 * @i2c_client_list_node: part of i2c_client_list
135 * @lock : lock for sending i2c commands
136 * @wake_token : wake token array of zeros
137 * @wake_token_sz : size in bytes of the wake_token
138 * @tfm_count : number of active crypto transformations on i2c client
140 * Reads and writes from/to the i2c client are sequential. The first byte
141 * transmitted to the device is treated as the byte size. Any attempt to send
142 * more than this number of bytes will cause the device to not ACK those bytes.
143 * After the host writes a single command byte to the input buffer, reads are
144 * prohibited until after the device completes command execution. Use a mutex
145 * when sending i2c commands.
147 struct atmel_i2c_client_priv {
148 struct i2c_client *client;
149 struct list_head i2c_client_list_node;
151 u8 wake_token[WAKE_TOKEN_MAX_SIZE];
152 size_t wake_token_sz;
153 atomic_t tfm_count ____cacheline_aligned;
158 * atmel_i2c_work_data - data structure representing the work
159 * @ctx : transformation context.
160 * @cbk : pointer to a callback function to be invoked upon completion of this
161 * request. This has the form:
162 * callback(struct atmel_i2c_work_data *work_data, void *areq, u8 status)
164 * @work_data: data structure representing the work
165 * @areq : optional pointer to an argument passed with the original
167 * @status : status returned from the i2c client device or i2c error.
168 * @areq: optional pointer to a user argument for use at callback time.
169 * @work: describes the task to be executed.
170 * @cmd : structure used for communicating with the device.
172 struct atmel_i2c_work_data {
174 struct i2c_client *client;
175 void (*cbk)(struct atmel_i2c_work_data *work_data, void *areq,
178 struct work_struct work;
179 struct atmel_i2c_cmd cmd;
182 int atmel_i2c_probe(struct i2c_client *client, const struct i2c_device_id *id);
184 void atmel_i2c_enqueue(struct atmel_i2c_work_data *work_data,
185 void (*cbk)(struct atmel_i2c_work_data *work_data,
186 void *areq, int status),
189 int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd);
191 void atmel_i2c_init_read_cmd(struct atmel_i2c_cmd *cmd);
192 void atmel_i2c_init_random_cmd(struct atmel_i2c_cmd *cmd);
193 void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid);
194 int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd,
195 struct scatterlist *pubkey);
197 #endif /* __ATMEL_I2C_H__ */