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/* 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>
#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;
u16 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__ */
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