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Diffstat (limited to 'drivers/crypto/atmel-i2c.h')
| -rw-r--r-- | drivers/crypto/atmel-i2c.h | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/crypto/atmel-i2c.h b/drivers/crypto/atmel-i2c.h new file mode 100644 index 000000000000..21860b99c3e3 --- /dev/null +++ b/drivers/crypto/atmel-i2c.h @@ -0,0 +1,197 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2017, Microchip Technology Inc. + * Author: Tudor Ambarus <tudor.ambarus@microchip.com> + */ + +#ifndef __ATMEL_I2C_H__ +#define __ATMEL_I2C_H__ + +#include <linux/hw_random.h> +#include <linux/types.h> + +#define ATMEL_ECC_PRIORITY 300 + +#define COMMAND 0x03 /* packet function */ +#define SLEEP_TOKEN 0x01 +#define WAKE_TOKEN_MAX_SIZE 8 + +/* Definitions of Data and Command sizes */ +#define WORD_ADDR_SIZE 1 +#define COUNT_SIZE 1 +#define CRC_SIZE 2 +#define CMD_OVERHEAD_SIZE (COUNT_SIZE + CRC_SIZE) + +/* size in bytes of the n prime */ +#define ATMEL_ECC_NIST_P256_N_SIZE 32 +#define ATMEL_ECC_PUBKEY_SIZE (2 * ATMEL_ECC_NIST_P256_N_SIZE) + +#define STATUS_RSP_SIZE 4 +#define ECDH_RSP_SIZE (32 + CMD_OVERHEAD_SIZE) +#define GENKEY_RSP_SIZE (ATMEL_ECC_PUBKEY_SIZE + \ + CMD_OVERHEAD_SIZE) +#define READ_RSP_SIZE (4 + CMD_OVERHEAD_SIZE) +#define RANDOM_RSP_SIZE (32 + CMD_OVERHEAD_SIZE) +#define MAX_RSP_SIZE GENKEY_RSP_SIZE + +/** + * atmel_i2c_cmd - structure used for communicating with the device. + * @word_addr: indicates the function of the packet sent to the device. This + * byte should have a value of COMMAND for normal operation. + * @count : number of bytes to be transferred to (or from) the device. + * @opcode : the command code. + * @param1 : the first parameter; always present. + * @param2 : the second parameter; always present. + * @data : optional remaining input data. Includes a 2-byte CRC. + * @rxsize : size of the data received from i2c client. + * @msecs : command execution time in milliseconds + */ +struct atmel_i2c_cmd { + u8 word_addr; + u8 count; + u8 opcode; + u8 param1; + __le16 param2; + u8 data[MAX_RSP_SIZE]; + u8 msecs; + u16 rxsize; +} __packed; + +/* Status/Error codes */ +#define STATUS_SIZE 0x04 +#define STATUS_NOERR 0x00 +#define STATUS_WAKE_SUCCESSFUL 0x11 + +static const struct { + u8 value; + const char *error_text; +} error_list[] = { + { 0x01, "CheckMac or Verify miscompare" }, + { 0x03, "Parse Error" }, + { 0x05, "ECC Fault" }, + { 0x0F, "Execution Error" }, + { 0xEE, "Watchdog about to expire" }, + { 0xFF, "CRC or other communication error" }, +}; + +/* Definitions for eeprom organization */ +#define CONFIG_ZONE 0 + +/* Definitions for Indexes common to all commands */ +#define RSP_DATA_IDX 1 /* buffer index of data in response */ +#define DATA_SLOT_2 2 /* used for ECDH private key */ + +/* Definitions for the device lock state */ +#define DEVICE_LOCK_ADDR 0x15 +#define LOCK_VALUE_IDX (RSP_DATA_IDX + 2) +#define LOCK_CONFIG_IDX (RSP_DATA_IDX + 3) + +/* + * Wake High delay to data communication (microseconds). SDA should be stable + * high for this entire duration. + */ +#define TWHI_MIN 1500 +#define TWHI_MAX 1550 + +/* Wake Low duration */ +#define TWLO_USEC 60 + +/* Command execution time (milliseconds) */ +#define MAX_EXEC_TIME_ECDH 58 +#define MAX_EXEC_TIME_GENKEY 115 +#define MAX_EXEC_TIME_READ 1 +#define MAX_EXEC_TIME_RANDOM 50 + +/* Command opcode */ +#define OPCODE_ECDH 0x43 +#define OPCODE_GENKEY 0x40 +#define OPCODE_READ 0x02 +#define OPCODE_RANDOM 0x1b + +/* Definitions for the READ Command */ +#define READ_COUNT 7 + +/* Definitions for the RANDOM Command */ +#define RANDOM_COUNT 7 + +/* Definitions for the GenKey Command */ +#define GENKEY_COUNT 7 +#define GENKEY_MODE_PRIVATE 0x04 + +/* Definitions for the ECDH Command */ +#define ECDH_COUNT 71 +#define ECDH_PREFIX_MODE 0x00 + +/* Used for binding tfm objects to i2c clients. */ +struct atmel_ecc_driver_data { + struct list_head i2c_client_list; + spinlock_t i2c_list_lock; +} ____cacheline_aligned; + +/** + * atmel_i2c_client_priv - i2c_client private data + * @client : pointer to i2c client device + * @i2c_client_list_node: part of i2c_client_list + * @lock : lock for sending i2c commands + * @wake_token : wake token array of zeros + * @wake_token_sz : size in bytes of the wake_token + * @tfm_count : number of active crypto transformations on i2c client + * + * Reads and writes from/to the i2c client are sequential. The first byte + * transmitted to the device is treated as the byte size. Any attempt to send + * more than this number of bytes will cause the device to not ACK those bytes. + * After the host writes a single command byte to the input buffer, reads are + * prohibited until after the device completes command execution. Use a mutex + * when sending i2c commands. + */ +struct atmel_i2c_client_priv { + struct i2c_client *client; + struct list_head i2c_client_list_node; + struct mutex lock; + u8 wake_token[WAKE_TOKEN_MAX_SIZE]; + size_t wake_token_sz; + atomic_t tfm_count ____cacheline_aligned; + struct hwrng hwrng; +}; + +/** + * atmel_i2c_work_data - data structure representing the work + * @ctx : transformation context. + * @cbk : pointer to a callback function to be invoked upon completion of this + * request. This has the form: + * callback(struct atmel_i2c_work_data *work_data, void *areq, u8 status) + * where: + * @work_data: data structure representing the work + * @areq : optional pointer to an argument passed with the original + * request. + * @status : status returned from the i2c client device or i2c error. + * @areq: optional pointer to a user argument for use at callback time. + * @work: describes the task to be executed. + * @cmd : structure used for communicating with the device. + */ +struct atmel_i2c_work_data { + void *ctx; + struct i2c_client *client; + void (*cbk)(struct atmel_i2c_work_data *work_data, void *areq, + int status); + void *areq; + struct work_struct work; + struct atmel_i2c_cmd cmd; +}; + +int atmel_i2c_probe(struct i2c_client *client, const struct i2c_device_id *id); + +void atmel_i2c_enqueue(struct atmel_i2c_work_data *work_data, + void (*cbk)(struct atmel_i2c_work_data *work_data, + void *areq, int status), + void *areq); + +int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd); + +void atmel_i2c_init_read_cmd(struct atmel_i2c_cmd *cmd); +void atmel_i2c_init_random_cmd(struct atmel_i2c_cmd *cmd); +void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid); +int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd, + struct scatterlist *pubkey); + +#endif /* __ATMEL_I2C_H__ */ |