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 | |