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