crypto: atmel-ecc - factor out code that can be shared
In preparation of adding support for the random number generator in Atmel atsha204a devices, refactor the existing atmel-ecc driver (which drives hardware that is closely related) so we can share the basic I2C and command queuing routines. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
parent
3c756aa346
commit
c34a320176
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@ -519,9 +519,13 @@ config CRYPTO_DEV_ATMEL_SHA
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To compile this driver as a module, choose M here: the module
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will be called atmel-sha.
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config CRYPTO_DEV_ATMEL_I2C
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tristate
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config CRYPTO_DEV_ATMEL_ECC
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tristate "Support for Microchip / Atmel ECC hw accelerator"
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depends on I2C
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select CRYPTO_DEV_ATMEL_I2C
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select CRYPTO_ECDH
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select CRC16
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help
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@ -2,6 +2,7 @@
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obj-$(CONFIG_CRYPTO_DEV_ATMEL_AES) += atmel-aes.o
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obj-$(CONFIG_CRYPTO_DEV_ATMEL_SHA) += atmel-sha.o
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obj-$(CONFIG_CRYPTO_DEV_ATMEL_TDES) += atmel-tdes.o
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obj-$(CONFIG_CRYPTO_DEV_ATMEL_I2C) += atmel-i2c.o
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obj-$(CONFIG_CRYPTO_DEV_ATMEL_ECC) += atmel-ecc.o
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obj-$(CONFIG_CRYPTO_DEV_CAVIUM_ZIP) += cavium/
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obj-$(CONFIG_CRYPTO_DEV_CCP) += ccp/
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@ -6,8 +6,6 @@
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* Author: Tudor Ambarus <tudor.ambarus@microchip.com>
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*/
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#include <linux/bitrev.h>
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#include <linux/crc16.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/err.h>
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@ -23,41 +21,10 @@
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#include <crypto/internal/kpp.h>
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#include <crypto/ecdh.h>
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#include <crypto/kpp.h>
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#include "atmel-ecc.h"
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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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#include "atmel-i2c.h"
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static struct atmel_ecc_driver_data driver_data;
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/**
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* atmel_ecc_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_ecc_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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};
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/**
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* atmel_ecdh_ctx - transformation context
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* @client : pointer to i2c client device
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@ -80,188 +47,12 @@ struct atmel_ecdh_ctx {
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bool do_fallback;
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};
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/**
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* atmel_ecc_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_ecc_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_ecc_work_data {
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struct atmel_ecdh_ctx *ctx;
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void (*cbk)(struct atmel_ecc_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_ecc_cmd cmd;
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};
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static u16 atmel_ecc_crc16(u16 crc, const u8 *buffer, size_t len)
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{
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return cpu_to_le16(bitrev16(crc16(crc, buffer, len)));
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}
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/**
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* atmel_ecc_checksum() - Generate 16-bit CRC as required by ATMEL ECC.
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* CRC16 verification of the count, opcode, param1, param2 and data bytes.
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* The checksum is saved in little-endian format in the least significant
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* two bytes of the command. CRC polynomial is 0x8005 and the initial register
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* value should be zero.
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*
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* @cmd : structure used for communicating with the device.
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*/
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static void atmel_ecc_checksum(struct atmel_ecc_cmd *cmd)
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{
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u8 *data = &cmd->count;
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size_t len = cmd->count - CRC_SIZE;
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u16 *crc16 = (u16 *)(data + len);
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*crc16 = atmel_ecc_crc16(0, data, len);
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}
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static void atmel_ecc_init_read_cmd(struct atmel_ecc_cmd *cmd)
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{
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cmd->word_addr = COMMAND;
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cmd->opcode = OPCODE_READ;
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/*
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* Read the word from Configuration zone that contains the lock bytes
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* (UserExtra, Selector, LockValue, LockConfig).
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*/
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cmd->param1 = CONFIG_ZONE;
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cmd->param2 = DEVICE_LOCK_ADDR;
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cmd->count = READ_COUNT;
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atmel_ecc_checksum(cmd);
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cmd->msecs = MAX_EXEC_TIME_READ;
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cmd->rxsize = READ_RSP_SIZE;
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}
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static void atmel_ecc_init_genkey_cmd(struct atmel_ecc_cmd *cmd, u16 keyid)
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{
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cmd->word_addr = COMMAND;
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cmd->count = GENKEY_COUNT;
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cmd->opcode = OPCODE_GENKEY;
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cmd->param1 = GENKEY_MODE_PRIVATE;
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/* a random private key will be generated and stored in slot keyID */
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cmd->param2 = cpu_to_le16(keyid);
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atmel_ecc_checksum(cmd);
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cmd->msecs = MAX_EXEC_TIME_GENKEY;
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cmd->rxsize = GENKEY_RSP_SIZE;
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}
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static int atmel_ecc_init_ecdh_cmd(struct atmel_ecc_cmd *cmd,
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struct scatterlist *pubkey)
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{
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size_t copied;
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cmd->word_addr = COMMAND;
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cmd->count = ECDH_COUNT;
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cmd->opcode = OPCODE_ECDH;
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cmd->param1 = ECDH_PREFIX_MODE;
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/* private key slot */
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cmd->param2 = cpu_to_le16(DATA_SLOT_2);
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/*
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* The device only supports NIST P256 ECC keys. The public key size will
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* always be the same. Use a macro for the key size to avoid unnecessary
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* computations.
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*/
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copied = sg_copy_to_buffer(pubkey,
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sg_nents_for_len(pubkey,
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ATMEL_ECC_PUBKEY_SIZE),
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cmd->data, ATMEL_ECC_PUBKEY_SIZE);
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if (copied != ATMEL_ECC_PUBKEY_SIZE)
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return -EINVAL;
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atmel_ecc_checksum(cmd);
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cmd->msecs = MAX_EXEC_TIME_ECDH;
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cmd->rxsize = ECDH_RSP_SIZE;
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return 0;
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}
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/*
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* After wake and after execution of a command, there will be error, status, or
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* result bytes in the device's output register that can be retrieved by the
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* system. When the length of that group is four bytes, the codes returned are
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* detailed in error_list.
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*/
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static int atmel_ecc_status(struct device *dev, u8 *status)
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{
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size_t err_list_len = ARRAY_SIZE(error_list);
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int i;
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u8 err_id = status[1];
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if (*status != STATUS_SIZE)
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return 0;
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if (err_id == STATUS_WAKE_SUCCESSFUL || err_id == STATUS_NOERR)
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return 0;
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for (i = 0; i < err_list_len; i++)
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if (error_list[i].value == err_id)
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break;
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/* if err_id is not in the error_list then ignore it */
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if (i != err_list_len) {
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dev_err(dev, "%02x: %s:\n", err_id, error_list[i].error_text);
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return err_id;
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}
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return 0;
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}
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static int atmel_ecc_wakeup(struct i2c_client *client)
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{
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struct atmel_ecc_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
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u8 status[STATUS_RSP_SIZE];
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int ret;
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/*
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* The device ignores any levels or transitions on the SCL pin when the
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* device is idle, asleep or during waking up. Don't check for error
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* when waking up the device.
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*/
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i2c_master_send(client, i2c_priv->wake_token, i2c_priv->wake_token_sz);
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/*
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* Wait to wake the device. Typical execution times for ecdh and genkey
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* are around tens of milliseconds. Delta is chosen to 50 microseconds.
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*/
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usleep_range(TWHI_MIN, TWHI_MAX);
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ret = i2c_master_recv(client, status, STATUS_SIZE);
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if (ret < 0)
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return ret;
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return atmel_ecc_status(&client->dev, status);
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}
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static int atmel_ecc_sleep(struct i2c_client *client)
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{
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u8 sleep = SLEEP_TOKEN;
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return i2c_master_send(client, &sleep, 1);
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}
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static void atmel_ecdh_done(struct atmel_ecc_work_data *work_data, void *areq,
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static void atmel_ecdh_done(struct atmel_i2c_work_data *work_data, void *areq,
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int status)
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{
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struct kpp_request *req = areq;
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struct atmel_ecdh_ctx *ctx = work_data->ctx;
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struct atmel_ecc_cmd *cmd = &work_data->cmd;
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struct atmel_i2c_cmd *cmd = &work_data->cmd;
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size_t copied, n_sz;
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if (status)
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@ -282,82 +73,6 @@ free_work_data:
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kpp_request_complete(req, status);
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}
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/*
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* atmel_ecc_send_receive() - send a command to the device and receive its
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* response.
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* @client: i2c client device
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* @cmd : structure used to communicate with the device
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*
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* After the device receives a Wake token, a watchdog counter starts within the
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* device. After the watchdog timer expires, the device enters sleep mode
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* regardless of whether some I/O transmission or command execution is in
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* progress. If a command is attempted when insufficient time remains prior to
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* watchdog timer execution, the device will return the watchdog timeout error
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* code without attempting to execute the command. There is no way to reset the
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* counter other than to put the device into sleep or idle mode and then
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* wake it up again.
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*/
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static int atmel_ecc_send_receive(struct i2c_client *client,
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struct atmel_ecc_cmd *cmd)
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{
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struct atmel_ecc_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
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int ret;
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mutex_lock(&i2c_priv->lock);
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ret = atmel_ecc_wakeup(client);
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if (ret)
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goto err;
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/* send the command */
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ret = i2c_master_send(client, (u8 *)cmd, cmd->count + WORD_ADDR_SIZE);
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if (ret < 0)
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goto err;
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/* delay the appropriate amount of time for command to execute */
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msleep(cmd->msecs);
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/* receive the response */
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ret = i2c_master_recv(client, cmd->data, cmd->rxsize);
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if (ret < 0)
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goto err;
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/* put the device into low-power mode */
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ret = atmel_ecc_sleep(client);
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if (ret < 0)
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goto err;
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mutex_unlock(&i2c_priv->lock);
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return atmel_ecc_status(&client->dev, cmd->data);
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err:
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mutex_unlock(&i2c_priv->lock);
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return ret;
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}
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static void atmel_ecc_work_handler(struct work_struct *work)
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{
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struct atmel_ecc_work_data *work_data =
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container_of(work, struct atmel_ecc_work_data, work);
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struct atmel_ecc_cmd *cmd = &work_data->cmd;
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struct i2c_client *client = work_data->ctx->client;
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int status;
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status = atmel_ecc_send_receive(client, cmd);
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work_data->cbk(work_data, work_data->areq, status);
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}
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static void atmel_ecc_enqueue(struct atmel_ecc_work_data *work_data,
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void (*cbk)(struct atmel_ecc_work_data *work_data,
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void *areq, int status),
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void *areq)
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{
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work_data->cbk = (void *)cbk;
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work_data->areq = areq;
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INIT_WORK(&work_data->work, atmel_ecc_work_handler);
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schedule_work(&work_data->work);
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}
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static unsigned int atmel_ecdh_supported_curve(unsigned int curve_id)
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{
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if (curve_id == ECC_CURVE_NIST_P256)
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@ -374,7 +89,7 @@ static int atmel_ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
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unsigned int len)
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{
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struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
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struct atmel_ecc_cmd *cmd;
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struct atmel_i2c_cmd *cmd;
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void *public_key;
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struct ecdh params;
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int ret = -ENOMEM;
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@ -412,9 +127,9 @@ static int atmel_ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
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ctx->do_fallback = false;
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ctx->curve_id = params.curve_id;
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atmel_ecc_init_genkey_cmd(cmd, DATA_SLOT_2);
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atmel_i2c_init_genkey_cmd(cmd, DATA_SLOT_2);
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ret = atmel_ecc_send_receive(ctx->client, cmd);
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ret = atmel_i2c_send_receive(ctx->client, cmd);
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if (ret)
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goto free_public_key;
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@ -444,6 +159,9 @@ static int atmel_ecdh_generate_public_key(struct kpp_request *req)
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return crypto_kpp_generate_public_key(req);
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}
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if (!ctx->public_key)
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return -EINVAL;
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/* might want less than we've got */
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nbytes = min_t(size_t, ATMEL_ECC_PUBKEY_SIZE, req->dst_len);
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@ -461,7 +179,7 @@ static int atmel_ecdh_compute_shared_secret(struct kpp_request *req)
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{
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struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
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struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm);
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struct atmel_ecc_work_data *work_data;
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struct atmel_i2c_work_data *work_data;
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gfp_t gfp;
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int ret;
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@ -482,12 +200,13 @@ static int atmel_ecdh_compute_shared_secret(struct kpp_request *req)
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return -ENOMEM;
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work_data->ctx = ctx;
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work_data->client = ctx->client;
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ret = atmel_ecc_init_ecdh_cmd(&work_data->cmd, req->src);
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ret = atmel_i2c_init_ecdh_cmd(&work_data->cmd, req->src);
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if (ret)
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goto free_work_data;
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atmel_ecc_enqueue(work_data, atmel_ecdh_done, req);
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atmel_i2c_enqueue(work_data, atmel_ecdh_done, req);
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return -EINPROGRESS;
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@ -498,7 +217,7 @@ free_work_data:
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static struct i2c_client *atmel_ecc_i2c_client_alloc(void)
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{
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struct atmel_ecc_i2c_client_priv *i2c_priv, *min_i2c_priv = NULL;
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struct atmel_i2c_client_priv *i2c_priv, *min_i2c_priv = NULL;
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struct i2c_client *client = ERR_PTR(-ENODEV);
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int min_tfm_cnt = INT_MAX;
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int tfm_cnt;
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@ -533,7 +252,7 @@ static struct i2c_client *atmel_ecc_i2c_client_alloc(void)
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static void atmel_ecc_i2c_client_free(struct i2c_client *client)
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{
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struct atmel_ecc_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
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struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
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atomic_dec(&i2c_priv->tfm_count);
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}
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@ -604,99 +323,18 @@ static struct kpp_alg atmel_ecdh = {
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},
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};
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static inline size_t atmel_ecc_wake_token_sz(u32 bus_clk_rate)
|
||||
{
|
||||
u32 no_of_bits = DIV_ROUND_UP(TWLO_USEC * bus_clk_rate, USEC_PER_SEC);
|
||||
|
||||
/* return the size of the wake_token in bytes */
|
||||
return DIV_ROUND_UP(no_of_bits, 8);
|
||||
}
|
||||
|
||||
static int device_sanity_check(struct i2c_client *client)
|
||||
{
|
||||
struct atmel_ecc_cmd *cmd;
|
||||
int ret;
|
||||
|
||||
cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
|
||||
if (!cmd)
|
||||
return -ENOMEM;
|
||||
|
||||
atmel_ecc_init_read_cmd(cmd);
|
||||
|
||||
ret = atmel_ecc_send_receive(client, cmd);
|
||||
if (ret)
|
||||
goto free_cmd;
|
||||
|
||||
/*
|
||||
* It is vital that the Configuration, Data and OTP zones be locked
|
||||
* prior to release into the field of the system containing the device.
|
||||
* Failure to lock these zones may permit modification of any secret
|
||||
* keys and may lead to other security problems.
|
||||
*/
|
||||
if (cmd->data[LOCK_CONFIG_IDX] || cmd->data[LOCK_VALUE_IDX]) {
|
||||
dev_err(&client->dev, "Configuration or Data and OTP zones are unlocked!\n");
|
||||
ret = -ENOTSUPP;
|
||||
}
|
||||
|
||||
/* fall through */
|
||||
free_cmd:
|
||||
kfree(cmd);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int atmel_ecc_probe(struct i2c_client *client,
|
||||
const struct i2c_device_id *id)
|
||||
{
|
||||
struct atmel_ecc_i2c_client_priv *i2c_priv;
|
||||
struct device *dev = &client->dev;
|
||||
struct atmel_i2c_client_priv *i2c_priv;
|
||||
int ret;
|
||||
u32 bus_clk_rate;
|
||||
|
||||
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
|
||||
dev_err(dev, "I2C_FUNC_I2C not supported\n");
|
||||
return -ENODEV;
|
||||
}
|
||||
|
||||
clk_rate = i2c_acpi_find_bus_speed(&client->adapter->dev);
|
||||
if (!clk_rate) {
|
||||
ret = device_property_read_u32(&client->adapter->dev,
|
||||
"clock-frequency", &bus_clk_rate);
|
||||
if (ret) {
|
||||
dev_err(dev, "failed to read clock-frequency property\n");
|
||||
return ret;
|
||||
}
|
||||
}
|
||||
|
||||
if (bus_clk_rate > 1000000L) {
|
||||
dev_err(dev, "%d exceeds maximum supported clock frequency (1MHz)\n",
|
||||
bus_clk_rate);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
i2c_priv = devm_kmalloc(dev, sizeof(*i2c_priv), GFP_KERNEL);
|
||||
if (!i2c_priv)
|
||||
return -ENOMEM;
|
||||
|
||||
i2c_priv->client = client;
|
||||
mutex_init(&i2c_priv->lock);
|
||||
|
||||
/*
|
||||
* WAKE_TOKEN_MAX_SIZE was calculated for the maximum bus_clk_rate -
|
||||
* 1MHz. The previous bus_clk_rate check ensures us that wake_token_sz
|
||||
* will always be smaller than or equal to WAKE_TOKEN_MAX_SIZE.
|
||||
*/
|
||||
i2c_priv->wake_token_sz = atmel_ecc_wake_token_sz(bus_clk_rate);
|
||||
|
||||
memset(i2c_priv->wake_token, 0, sizeof(i2c_priv->wake_token));
|
||||
|
||||
atomic_set(&i2c_priv->tfm_count, 0);
|
||||
|
||||
i2c_set_clientdata(client, i2c_priv);
|
||||
|
||||
ret = device_sanity_check(client);
|
||||
ret = atmel_i2c_probe(client, id);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
i2c_priv = i2c_get_clientdata(client);
|
||||
|
||||
spin_lock(&driver_data.i2c_list_lock);
|
||||
list_add_tail(&i2c_priv->i2c_client_list_node,
|
||||
&driver_data.i2c_client_list);
|
||||
|
@ -708,10 +346,10 @@ static int atmel_ecc_probe(struct i2c_client *client,
|
|||
list_del(&i2c_priv->i2c_client_list_node);
|
||||
spin_unlock(&driver_data.i2c_list_lock);
|
||||
|
||||
dev_err(dev, "%s alg registration failed\n",
|
||||
dev_err(&client->dev, "%s alg registration failed\n",
|
||||
atmel_ecdh.base.cra_driver_name);
|
||||
} else {
|
||||
dev_info(dev, "atmel ecc algorithms registered in /proc/crypto\n");
|
||||
dev_info(&client->dev, "atmel ecc algorithms registered in /proc/crypto\n");
|
||||
}
|
||||
|
||||
return ret;
|
||||
|
@ -719,7 +357,7 @@ static int atmel_ecc_probe(struct i2c_client *client,
|
|||
|
||||
static int atmel_ecc_remove(struct i2c_client *client)
|
||||
{
|
||||
struct atmel_ecc_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
|
||||
struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
|
||||
|
||||
/* Return EBUSY if i2c client already allocated. */
|
||||
if (atomic_read(&i2c_priv->tfm_count)) {
|
||||
|
|
349
drivers/crypto/atmel-i2c.c
Normal file
349
drivers/crypto/atmel-i2c.c
Normal file
|
@ -0,0 +1,349 @@
|
|||
// SPDX-License-Identifier: GPL-2.0
|
||||
/*
|
||||
* Microchip / Atmel ECC (I2C) driver.
|
||||
*
|
||||
* Copyright (c) 2017, Microchip Technology Inc.
|
||||
* Author: Tudor Ambarus <tudor.ambarus@microchip.com>
|
||||
*/
|
||||
|
||||
#include <linux/bitrev.h>
|
||||
#include <linux/crc16.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/device.h>
|
||||
#include <linux/err.h>
|
||||
#include <linux/errno.h>
|
||||
#include <linux/i2c.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/scatterlist.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/workqueue.h>
|
||||
#include "atmel-i2c.h"
|
||||
|
||||
/**
|
||||
* atmel_i2c_checksum() - Generate 16-bit CRC as required by ATMEL ECC.
|
||||
* CRC16 verification of the count, opcode, param1, param2 and data bytes.
|
||||
* The checksum is saved in little-endian format in the least significant
|
||||
* two bytes of the command. CRC polynomial is 0x8005 and the initial register
|
||||
* value should be zero.
|
||||
*
|
||||
* @cmd : structure used for communicating with the device.
|
||||
*/
|
||||
static void atmel_i2c_checksum(struct atmel_i2c_cmd *cmd)
|
||||
{
|
||||
u8 *data = &cmd->count;
|
||||
size_t len = cmd->count - CRC_SIZE;
|
||||
u16 *__crc16 = (u16 *)(data + len);
|
||||
|
||||
*__crc16 = cpu_to_le16(bitrev16(crc16(0, data, len)));
|
||||
}
|
||||
|
||||
void atmel_i2c_init_read_cmd(struct atmel_i2c_cmd *cmd)
|
||||
{
|
||||
cmd->word_addr = COMMAND;
|
||||
cmd->opcode = OPCODE_READ;
|
||||
/*
|
||||
* Read the word from Configuration zone that contains the lock bytes
|
||||
* (UserExtra, Selector, LockValue, LockConfig).
|
||||
*/
|
||||
cmd->param1 = CONFIG_ZONE;
|
||||
cmd->param2 = DEVICE_LOCK_ADDR;
|
||||
cmd->count = READ_COUNT;
|
||||
|
||||
atmel_i2c_checksum(cmd);
|
||||
|
||||
cmd->msecs = MAX_EXEC_TIME_READ;
|
||||
cmd->rxsize = READ_RSP_SIZE;
|
||||
}
|
||||
EXPORT_SYMBOL(atmel_i2c_init_read_cmd);
|
||||
|
||||
void atmel_i2c_init_genkey_cmd(struct atmel_i2c_cmd *cmd, u16 keyid)
|
||||
{
|
||||
cmd->word_addr = COMMAND;
|
||||
cmd->count = GENKEY_COUNT;
|
||||
cmd->opcode = OPCODE_GENKEY;
|
||||
cmd->param1 = GENKEY_MODE_PRIVATE;
|
||||
/* a random private key will be generated and stored in slot keyID */
|
||||
cmd->param2 = cpu_to_le16(keyid);
|
||||
|
||||
atmel_i2c_checksum(cmd);
|
||||
|
||||
cmd->msecs = MAX_EXEC_TIME_GENKEY;
|
||||
cmd->rxsize = GENKEY_RSP_SIZE;
|
||||
}
|
||||
EXPORT_SYMBOL(atmel_i2c_init_genkey_cmd);
|
||||
|
||||
int atmel_i2c_init_ecdh_cmd(struct atmel_i2c_cmd *cmd,
|
||||
struct scatterlist *pubkey)
|
||||
{
|
||||
size_t copied;
|
||||
|
||||
cmd->word_addr = COMMAND;
|
||||
cmd->count = ECDH_COUNT;
|
||||
cmd->opcode = OPCODE_ECDH;
|
||||
cmd->param1 = ECDH_PREFIX_MODE;
|
||||
/* private key slot */
|
||||
cmd->param2 = cpu_to_le16(DATA_SLOT_2);
|
||||
|
||||
/*
|
||||
* The device only supports NIST P256 ECC keys. The public key size will
|
||||
* always be the same. Use a macro for the key size to avoid unnecessary
|
||||
* computations.
|
||||
*/
|
||||
copied = sg_copy_to_buffer(pubkey,
|
||||
sg_nents_for_len(pubkey,
|
||||
ATMEL_ECC_PUBKEY_SIZE),
|
||||
cmd->data, ATMEL_ECC_PUBKEY_SIZE);
|
||||
if (copied != ATMEL_ECC_PUBKEY_SIZE)
|
||||
return -EINVAL;
|
||||
|
||||
atmel_i2c_checksum(cmd);
|
||||
|
||||
cmd->msecs = MAX_EXEC_TIME_ECDH;
|
||||
cmd->rxsize = ECDH_RSP_SIZE;
|
||||
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(atmel_i2c_init_ecdh_cmd);
|
||||
|
||||
/*
|
||||
* After wake and after execution of a command, there will be error, status, or
|
||||
* result bytes in the device's output register that can be retrieved by the
|
||||
* system. When the length of that group is four bytes, the codes returned are
|
||||
* detailed in error_list.
|
||||
*/
|
||||
static int atmel_i2c_status(struct device *dev, u8 *status)
|
||||
{
|
||||
size_t err_list_len = ARRAY_SIZE(error_list);
|
||||
int i;
|
||||
u8 err_id = status[1];
|
||||
|
||||
if (*status != STATUS_SIZE)
|
||||
return 0;
|
||||
|
||||
if (err_id == STATUS_WAKE_SUCCESSFUL || err_id == STATUS_NOERR)
|
||||
return 0;
|
||||
|
||||
for (i = 0; i < err_list_len; i++)
|
||||
if (error_list[i].value == err_id)
|
||||
break;
|
||||
|
||||
/* if err_id is not in the error_list then ignore it */
|
||||
if (i != err_list_len) {
|
||||
dev_err(dev, "%02x: %s:\n", err_id, error_list[i].error_text);
|
||||
return err_id;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int atmel_i2c_wakeup(struct i2c_client *client)
|
||||
{
|
||||
struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
|
||||
u8 status[STATUS_RSP_SIZE];
|
||||
int ret;
|
||||
|
||||
/*
|
||||
* The device ignores any levels or transitions on the SCL pin when the
|
||||
* device is idle, asleep or during waking up. Don't check for error
|
||||
* when waking up the device.
|
||||
*/
|
||||
i2c_master_send(client, i2c_priv->wake_token, i2c_priv->wake_token_sz);
|
||||
|
||||
/*
|
||||
* Wait to wake the device. Typical execution times for ecdh and genkey
|
||||
* are around tens of milliseconds. Delta is chosen to 50 microseconds.
|
||||
*/
|
||||
usleep_range(TWHI_MIN, TWHI_MAX);
|
||||
|
||||
ret = i2c_master_recv(client, status, STATUS_SIZE);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
return atmel_i2c_status(&client->dev, status);
|
||||
}
|
||||
|
||||
static int atmel_i2c_sleep(struct i2c_client *client)
|
||||
{
|
||||
u8 sleep = SLEEP_TOKEN;
|
||||
|
||||
return i2c_master_send(client, &sleep, 1);
|
||||
}
|
||||
|
||||
/*
|
||||
* atmel_i2c_send_receive() - send a command to the device and receive its
|
||||
* response.
|
||||
* @client: i2c client device
|
||||
* @cmd : structure used to communicate with the device
|
||||
*
|
||||
* After the device receives a Wake token, a watchdog counter starts within the
|
||||
* device. After the watchdog timer expires, the device enters sleep mode
|
||||
* regardless of whether some I/O transmission or command execution is in
|
||||
* progress. If a command is attempted when insufficient time remains prior to
|
||||
* watchdog timer execution, the device will return the watchdog timeout error
|
||||
* code without attempting to execute the command. There is no way to reset the
|
||||
* counter other than to put the device into sleep or idle mode and then
|
||||
* wake it up again.
|
||||
*/
|
||||
int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd)
|
||||
{
|
||||
struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client);
|
||||
int ret;
|
||||
|
||||
mutex_lock(&i2c_priv->lock);
|
||||
|
||||
ret = atmel_i2c_wakeup(client);
|
||||
if (ret)
|
||||
goto err;
|
||||
|
||||
/* send the command */
|
||||
ret = i2c_master_send(client, (u8 *)cmd, cmd->count + WORD_ADDR_SIZE);
|
||||
if (ret < 0)
|
||||
goto err;
|
||||
|
||||
/* delay the appropriate amount of time for command to execute */
|
||||
msleep(cmd->msecs);
|
||||
|
||||
/* receive the response */
|
||||
ret = i2c_master_recv(client, cmd->data, cmd->rxsize);
|
||||
if (ret < 0)
|
||||
goto err;
|
||||
|
||||
/* put the device into low-power mode */
|
||||
ret = atmel_i2c_sleep(client);
|
||||
if (ret < 0)
|
||||
goto err;
|
||||
|
||||
mutex_unlock(&i2c_priv->lock);
|
||||
return atmel_i2c_status(&client->dev, cmd->data);
|
||||
err:
|
||||
mutex_unlock(&i2c_priv->lock);
|
||||
return ret;
|
||||
}
|
||||
EXPORT_SYMBOL(atmel_i2c_send_receive);
|
||||
|
||||
static void atmel_i2c_work_handler(struct work_struct *work)
|
||||
{
|
||||
struct atmel_i2c_work_data *work_data =
|
||||
container_of(work, struct atmel_i2c_work_data, work);
|
||||
struct atmel_i2c_cmd *cmd = &work_data->cmd;
|
||||
struct i2c_client *client = work_data->client;
|
||||
int status;
|
||||
|
||||
status = atmel_i2c_send_receive(client, cmd);
|
||||
work_data->cbk(work_data, work_data->areq, status);
|
||||
}
|
||||
|
||||
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)
|
||||
{
|
||||
work_data->cbk = (void *)cbk;
|
||||
work_data->areq = areq;
|
||||
|
||||
INIT_WORK(&work_data->work, atmel_i2c_work_handler);
|
||||
schedule_work(&work_data->work);
|
||||
}
|
||||
EXPORT_SYMBOL(atmel_i2c_enqueue);
|
||||
|
||||
static inline size_t atmel_i2c_wake_token_sz(u32 bus_clk_rate)
|
||||
{
|
||||
u32 no_of_bits = DIV_ROUND_UP(TWLO_USEC * bus_clk_rate, USEC_PER_SEC);
|
||||
|
||||
/* return the size of the wake_token in bytes */
|
||||
return DIV_ROUND_UP(no_of_bits, 8);
|
||||
}
|
||||
|
||||
static int device_sanity_check(struct i2c_client *client)
|
||||
{
|
||||
struct atmel_i2c_cmd *cmd;
|
||||
int ret;
|
||||
|
||||
cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
|
||||
if (!cmd)
|
||||
return -ENOMEM;
|
||||
|
||||
atmel_i2c_init_read_cmd(cmd);
|
||||
|
||||
ret = atmel_i2c_send_receive(client, cmd);
|
||||
if (ret)
|
||||
goto free_cmd;
|
||||
|
||||
/*
|
||||
* It is vital that the Configuration, Data and OTP zones be locked
|
||||
* prior to release into the field of the system containing the device.
|
||||
* Failure to lock these zones may permit modification of any secret
|
||||
* keys and may lead to other security problems.
|
||||
*/
|
||||
if (cmd->data[LOCK_CONFIG_IDX] || cmd->data[LOCK_VALUE_IDX]) {
|
||||
dev_err(&client->dev, "Configuration or Data and OTP zones are unlocked!\n");
|
||||
ret = -ENOTSUPP;
|
||||
}
|
||||
|
||||
/* fall through */
|
||||
free_cmd:
|
||||
kfree(cmd);
|
||||
return ret;
|
||||
}
|
||||
|
||||
int atmel_i2c_probe(struct i2c_client *client, const struct i2c_device_id *id)
|
||||
{
|
||||
struct atmel_i2c_client_priv *i2c_priv;
|
||||
struct device *dev = &client->dev;
|
||||
int ret;
|
||||
u32 bus_clk_rate;
|
||||
|
||||
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
|
||||
dev_err(dev, "I2C_FUNC_I2C not supported\n");
|
||||
return -ENODEV;
|
||||
}
|
||||
|
||||
bus_clk_rate = i2c_acpi_find_bus_speed(&client->adapter->dev);
|
||||
if (!bus_clk_rate) {
|
||||
ret = device_property_read_u32(&client->adapter->dev,
|
||||
"clock-frequency", &bus_clk_rate);
|
||||
if (ret) {
|
||||
dev_err(dev, "failed to read clock-frequency property\n");
|
||||
return ret;
|
||||
}
|
||||
}
|
||||
|
||||
if (bus_clk_rate > 1000000L) {
|
||||
dev_err(dev, "%d exceeds maximum supported clock frequency (1MHz)\n",
|
||||
bus_clk_rate);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
i2c_priv = devm_kmalloc(dev, sizeof(*i2c_priv), GFP_KERNEL);
|
||||
if (!i2c_priv)
|
||||
return -ENOMEM;
|
||||
|
||||
i2c_priv->client = client;
|
||||
mutex_init(&i2c_priv->lock);
|
||||
|
||||
/*
|
||||
* WAKE_TOKEN_MAX_SIZE was calculated for the maximum bus_clk_rate -
|
||||
* 1MHz. The previous bus_clk_rate check ensures us that wake_token_sz
|
||||
* will always be smaller than or equal to WAKE_TOKEN_MAX_SIZE.
|
||||
*/
|
||||
i2c_priv->wake_token_sz = atmel_i2c_wake_token_sz(bus_clk_rate);
|
||||
|
||||
memset(i2c_priv->wake_token, 0, sizeof(i2c_priv->wake_token));
|
||||
|
||||
atomic_set(&i2c_priv->tfm_count, 0);
|
||||
|
||||
i2c_set_clientdata(client, i2c_priv);
|
||||
|
||||
ret = device_sanity_check(client);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(atmel_i2c_probe);
|
||||
|
||||
MODULE_AUTHOR("Tudor Ambarus <tudor.ambarus@microchip.com>");
|
||||
MODULE_DESCRIPTION("Microchip / Atmel ECC (I2C) driver");
|
||||
MODULE_LICENSE("GPL v2");
|
|
@ -4,8 +4,8 @@
|
|||
* Author: Tudor Ambarus <tudor.ambarus@microchip.com>
|
||||
*/
|
||||
|
||||
#ifndef __ATMEL_ECC_H__
|
||||
#define __ATMEL_ECC_H__
|
||||
#ifndef __ATMEL_I2C_H__
|
||||
#define __ATMEL_I2C_H__
|
||||
|
||||
#define ATMEL_ECC_PRIORITY 300
|
||||
|
||||
|
@ -31,7 +31,7 @@
|
|||
#define MAX_RSP_SIZE GENKEY_RSP_SIZE
|
||||
|
||||
/**
|
||||
* atmel_ecc_cmd - structure used for communicating with the device.
|
||||
* 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.
|
||||
|
@ -42,7 +42,7 @@
|
|||
* @rxsize : size of the data received from i2c client.
|
||||
* @msecs : command execution time in milliseconds
|
||||
*/
|
||||
struct atmel_ecc_cmd {
|
||||
struct atmel_i2c_cmd {
|
||||
u8 word_addr;
|
||||
u8 count;
|
||||
u8 opcode;
|
||||
|
@ -113,4 +113,74 @@ static const struct {
|
|||
#define ECDH_COUNT 71
|
||||
#define ECDH_PREFIX_MODE 0x00
|
||||
|
||||
#endif /* __ATMEL_ECC_H__ */
|
||||
/* 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;
|
||||
};
|
||||
|
||||
/**
|
||||
* 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_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__ */
|
Loading…
Reference in a new issue