diff options
| -rw-r--r-- | Documentation/devicetree/bindings/crypto/atmel-crypto.txt | 13 | ||||
| -rw-r--r-- | drivers/crypto/Kconfig | 14 | ||||
| -rw-r--r-- | drivers/crypto/Makefile | 1 | ||||
| -rw-r--r-- | drivers/crypto/atmel-ecc.c | 781 | ||||
| -rw-r--r-- | drivers/crypto/atmel-ecc.h | 128 |
5 files changed, 937 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/crypto/atmel-crypto.txt b/Documentation/devicetree/bindings/crypto/atmel-crypto.txt index f2aab3dc2b52..7de1a9674c70 100644 --- a/Documentation/devicetree/bindings/crypto/atmel-crypto.txt +++ b/Documentation/devicetree/bindings/crypto/atmel-crypto.txt @@ -66,3 +66,16 @@ sha@f8034000 { dmas = <&dma1 2 17>; dma-names = "tx"; }; + +* Eliptic Curve Cryptography (I2C) + +Required properties: +- compatible : must be "atmel,atecc508a". +- reg: I2C bus address of the device. +- clock-frequency: must be present in the i2c controller node. + +Example: +atecc508a@C0 { + compatible = "atmel,atecc508a"; + reg = <0xC0>; +}; diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig index 5db825a469de..49397a9ae67c 100644 --- a/drivers/crypto/Kconfig +++ b/drivers/crypto/Kconfig @@ -525,6 +525,20 @@ config CRYPTO_DEV_ATMEL_SHA To compile this driver as a module, choose M here: the module will be called atmel-sha. +config CRYPTO_DEV_ATMEL_ECC + tristate "Support for Microchip / Atmel ECC hw accelerator" + depends on ARCH_AT91 || COMPILE_TEST + depends on I2C + select CRYPTO_ECDH + select CRC16 + help + Microhip / Atmel ECC hw accelerator. + Select this if you want to use the Microchip / Atmel module for + ECDH algorithm. + + To compile this driver as a module, choose M here: the module + will be called atmel-ecc. + config CRYPTO_DEV_CCP bool "Support for AMD Cryptographic Coprocessor" depends on ((X86 && PCI) || (ARM64 && (OF_ADDRESS || ACPI))) && HAS_IOMEM diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile index 2c555a3393b2..de629165fde7 100644 --- a/drivers/crypto/Makefile +++ b/drivers/crypto/Makefile @@ -1,6 +1,7 @@ obj-$(CONFIG_CRYPTO_DEV_ATMEL_AES) += atmel-aes.o obj-$(CONFIG_CRYPTO_DEV_ATMEL_SHA) += atmel-sha.o obj-$(CONFIG_CRYPTO_DEV_ATMEL_TDES) += atmel-tdes.o +obj-$(CONFIG_CRYPTO_DEV_ATMEL_ECC) += atmel-ecc.o obj-$(CONFIG_CRYPTO_DEV_BFIN_CRC) += bfin_crc.o obj-$(CONFIG_CRYPTO_DEV_CAVIUM_ZIP) += cavium/ obj-$(CONFIG_CRYPTO_DEV_CCP) += ccp/ diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c new file mode 100644 index 000000000000..66ab1021eba5 --- /dev/null +++ b/drivers/crypto/atmel-ecc.c @@ -0,0 +1,781 @@ +/* + * Microchip / Atmel ECC (I2C) driver. + * + * Copyright (c) 2017, Microchip Technology Inc. + * Author: Tudor Ambarus <tudor.ambarus@microchip.com> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#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/of_device.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/workqueue.h> +#include <crypto/internal/kpp.h> +#include <crypto/ecdh.h> +#include <crypto/kpp.h> +#include "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; + +static struct atmel_ecc_driver_data driver_data; + +/** + * atmel_ecc_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_ecc_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_ecdh_ctx - transformation context + * @client : pointer to i2c client device + * @fallback : used for unsupported curves or when user wants to use its own + * private key. + * @public_key : generated when calling set_secret(). It's the responsibility + * of the user to not call set_secret() while + * generate_public_key() or compute_shared_secret() are in flight. + * @curve_id : elliptic curve id + * @n_sz : size in bytes of the n prime + * @do_fallback: true when the device doesn't support the curve or when the user + * wants to use its own private key. + */ +struct atmel_ecdh_ctx { + struct i2c_client *client; + struct crypto_kpp *fallback; + const u8 *public_key; + unsigned int curve_id; + size_t n_sz; + bool do_fallback; +}; + +/** + * atmel_ecc_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_ecc_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 device. + * @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_ecc_work_data { + struct atmel_ecdh_ctx *ctx; + void (*cbk)(struct atmel_ecc_work_data *work_data, void *areq, + u8 status); + void *areq; + struct work_struct work; + struct atmel_ecc_cmd cmd; +}; + +static u16 atmel_ecc_crc16(u16 crc, const u8 *buffer, size_t len) +{ + return cpu_to_le16(bitrev16(crc16(crc, buffer, len))); +} + +/** + * atmel_ecc_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_ecc_checksum(struct atmel_ecc_cmd *cmd) +{ + u8 *data = &cmd->count; + size_t len = cmd->count - CRC_SIZE; + u16 *crc16 = (u16 *)(data + len); + + *crc16 = atmel_ecc_crc16(0, data, len); +} + +static void atmel_ecc_init_read_cmd(struct atmel_ecc_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_ecc_checksum(cmd); + + cmd->msecs = MAX_EXEC_TIME_READ; + cmd->rxsize = READ_RSP_SIZE; +} + +static void atmel_ecc_init_genkey_cmd(struct atmel_ecc_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_ecc_checksum(cmd); + + cmd->msecs = MAX_EXEC_TIME_GENKEY; + cmd->rxsize = GENKEY_RSP_SIZE; +} + +static int atmel_ecc_init_ecdh_cmd(struct atmel_ecc_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, 1, cmd->data, ATMEL_ECC_PUBKEY_SIZE); + if (copied != ATMEL_ECC_PUBKEY_SIZE) + return -EINVAL; + + atmel_ecc_checksum(cmd); + + cmd->msecs = MAX_EXEC_TIME_ECDH; + cmd->rxsize = ECDH_RSP_SIZE; + + return 0; +} + +/* + * 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_ecc_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_ecc_wakeup(struct i2c_client *client) +{ + struct atmel_ecc_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_ecc_status(&client->dev, status); +} + +static int atmel_ecc_sleep(struct i2c_client *client) +{ + u8 sleep = SLEEP_TOKEN; + + return i2c_master_send(client, &sleep, 1); +} + +static void atmel_ecdh_done(struct atmel_ecc_work_data *work_data, void *areq, + u8 status) +{ + struct kpp_request *req = areq; + struct atmel_ecdh_ctx *ctx = work_data->ctx; + struct atmel_ecc_cmd *cmd = &work_data->cmd; + size_t copied; + size_t n_sz = ctx->n_sz; + + if (status) + goto free_work_data; + + /* copy the shared secret */ + copied = sg_copy_from_buffer(req->dst, 1, &cmd->data[RSP_DATA_IDX], + n_sz); + if (copied != n_sz) + status = -EINVAL; + + /* fall through */ +free_work_data: + kzfree(work_data); + kpp_request_complete(req, status); +} + +/* + * atmel_ecc_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. + */ +static int atmel_ecc_send_receive(struct i2c_client *client, + struct atmel_ecc_cmd *cmd) +{ + struct atmel_ecc_i2c_client_priv *i2c_priv = i2c_get_clientdata(client); + int ret; + + mutex_lock(&i2c_priv->lock); + + ret = atmel_ecc_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_ecc_sleep(client); + if (ret < 0) + goto err; + + mutex_unlock(&i2c_priv->lock); + return atmel_ecc_status(&client->dev, cmd->data); +err: + mutex_unlock(&i2c_priv->lock); + return ret; +} + +static void atmel_ecc_work_handler(struct work_struct *work) +{ + struct atmel_ecc_work_data *work_data = + container_of(work, struct atmel_ecc_work_data, work); + struct atmel_ecc_cmd *cmd = &work_data->cmd; + struct i2c_client *client = work_data->ctx->client; + u8 status; + + status = atmel_ecc_send_receive(client, cmd); + work_data->cbk(work_data, work_data->areq, status); +} + +static void atmel_ecc_enqueue(struct atmel_ecc_work_data *work_data, + void (*cbk)(struct atmel_ecc_work_data *work_data, + void *areq, u8 status), + void *areq) +{ + work_data->cbk = (void *)cbk; + work_data->areq = areq; + + INIT_WORK(&work_data->work, atmel_ecc_work_handler); + schedule_work(&work_data->work); +} + +static unsigned int atmel_ecdh_supported_curve(unsigned int curve_id) +{ + if (curve_id == ECC_CURVE_NIST_P256) + return ATMEL_ECC_NIST_P256_N_SIZE; + + return 0; +} + +/* + * A random private key is generated and stored in the device. The device + * returns the pair public key. + */ +static int atmel_ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, + unsigned int len) +{ + struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm); + struct atmel_ecc_cmd *cmd; + void *public_key; + struct ecdh params; + int ret = -ENOMEM; + + /* free the old public key, if any */ + kfree(ctx->public_key); + /* make sure you don't free the old public key twice */ + ctx->public_key = NULL; + + if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0) { + dev_err(&ctx->client->dev, "crypto_ecdh_decode_key failed\n"); + return -EINVAL; + } + + ctx->n_sz = atmel_ecdh_supported_curve(params.curve_id); + if (!ctx->n_sz || params.key_size) { + /* fallback to ecdh software implementation */ + ctx->do_fallback = true; + return crypto_kpp_set_secret(ctx->fallback, buf, len); + } + + cmd = kmalloc(sizeof(*cmd), GFP_KERNEL); + if (!cmd) + return -ENOMEM; + + /* + * 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. + */ + public_key = kmalloc(ATMEL_ECC_PUBKEY_SIZE, GFP_KERNEL); + if (!public_key) + goto free_cmd; + + ctx->do_fallback = false; + ctx->curve_id = params.curve_id; + + atmel_ecc_init_genkey_cmd(cmd, DATA_SLOT_2); + + ret = atmel_ecc_send_receive(ctx->client, cmd); + if (ret) + goto free_public_key; + + /* save the public key */ + memcpy(public_key, &cmd->data[RSP_DATA_IDX], ATMEL_ECC_PUBKEY_SIZE); + ctx->public_key = public_key; + + kfree(cmd); + return 0; + +free_public_key: + kfree(public_key); +free_cmd: + kfree(cmd); + return ret; +} + +static int atmel_ecdh_generate_public_key(struct kpp_request *req) +{ + struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); + struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm); + size_t copied; + int ret = 0; + + if (ctx->do_fallback) { + kpp_request_set_tfm(req, ctx->fallback); + return crypto_kpp_generate_public_key(req); + } + + /* public key was saved at private key generation */ + copied = sg_copy_from_buffer(req->dst, 1, ctx->public_key, + ATMEL_ECC_PUBKEY_SIZE); + if (copied != ATMEL_ECC_PUBKEY_SIZE) + ret = -EINVAL; + + return ret; +} + +static int atmel_ecdh_compute_shared_secret(struct kpp_request *req) +{ + struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); + struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm); + struct atmel_ecc_work_data *work_data; + gfp_t gfp; + int ret; + + if (ctx->do_fallback) { + kpp_request_set_tfm(req, ctx->fallback); + return crypto_kpp_compute_shared_secret(req); + } + + gfp = (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ? GFP_KERNEL : + GFP_ATOMIC; + + work_data = kmalloc(sizeof(*work_data), gfp); + if (!work_data) + return -ENOMEM; + + work_data->ctx = ctx; + + ret = atmel_ecc_init_ecdh_cmd(&work_data->cmd, req->src); + if (ret) + goto free_work_data; + + atmel_ecc_enqueue(work_data, atmel_ecdh_done, req); + + return -EINPROGRESS; + +free_work_data: + kfree(work_data); + return ret; +} + +struct i2c_client *atmel_ecc_i2c_client_alloc(void) +{ + struct atmel_ecc_i2c_client_priv *i2c_priv, *min_i2c_priv = NULL; + struct i2c_client *client = ERR_PTR(-ENODEV); + int min_tfm_cnt = INT_MAX; + int tfm_cnt; + + spin_lock(&driver_data.i2c_list_lock); + + if (list_empty(&driver_data.i2c_client_list)) { + spin_unlock(&driver_data.i2c_list_lock); + return ERR_PTR(-ENODEV); + } + + list_for_each_entry(i2c_priv, &driver_data.i2c_client_list, + i2c_client_list_node) { + tfm_cnt = atomic_read(&i2c_priv->tfm_count); + if (tfm_cnt < min_tfm_cnt) { + min_tfm_cnt = tfm_cnt; + min_i2c_priv = i2c_priv; + } + if (!min_tfm_cnt) + break; + } + + if (min_i2c_priv) { + atomic_inc(&min_i2c_priv->tfm_count); + client = min_i2c_priv->client; + } + + spin_unlock(&driver_data.i2c_list_lock); + + return client; +} + +void atmel_ecc_i2c_client_free(struct i2c_client *client) +{ + struct atmel_ecc_i2c_client_priv *i2c_priv = i2c_get_clientdata(client); + + atomic_dec(&i2c_priv->tfm_count); +} + +static int atmel_ecdh_init_tfm(struct crypto_kpp *tfm) +{ + const char *alg = kpp_alg_name(tfm); + struct crypto_kpp *fallback; + struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm); + + ctx->client = atmel_ecc_i2c_client_alloc(); + if (IS_ERR(ctx->client)) { + pr_err("tfm - i2c_client binding failed\n"); + return PTR_ERR(ctx->client); + } + + fallback = crypto_alloc_kpp(alg, 0, CRYPTO_ALG_NEED_FALLBACK); + if (IS_ERR(fallback)) { + dev_err(&ctx->client->dev, "Failed to allocate transformation for '%s': %ld\n", + alg, PTR_ERR(fallback)); + return PTR_ERR(fallback); + } + + crypto_kpp_set_flags(fallback, crypto_kpp_get_flags(tfm)); + + dev_info(&ctx->client->dev, "Using '%s' as fallback implementation.\n", + crypto_tfm_alg_driver_name(crypto_kpp_tfm(fallback))); + + ctx->fallback = fallback; + + return 0; +} + +static void atmel_ecdh_exit_tfm(struct crypto_kpp *tfm) +{ + struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm); + + kfree(ctx->public_key); + crypto_free_kpp(ctx->fallback); + atmel_ecc_i2c_client_free(ctx->client); +} + +static unsigned int atmel_ecdh_max_size(struct crypto_kpp *tfm) +{ + struct atmel_ecdh_ctx *ctx = kpp_tfm_ctx(tfm); + + if (ctx->fallback) + return crypto_kpp_maxsize(ctx->fallback); + + /* + * 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. + */ + return ATMEL_ECC_PUBKEY_SIZE; +} + +static struct kpp_alg atmel_ecdh = { + .set_secret = atmel_ecdh_set_secret, + .generate_public_key = atmel_ecdh_generate_public_key, + .compute_shared_secret = atmel_ecdh_compute_shared_secret, + .init = atmel_ecdh_init_tfm, + .exit = atmel_ecdh_exit_tfm, + .max_size = atmel_ecdh_max_size, + .base = { + .cra_flags = CRYPTO_ALG_NEED_FALLBACK, + .cra_name = "ecdh", + .cra_driver_name = "atmel-ecdh", + .cra_priority = ATMEL_ECC_PRIORITY, + .cra_module = THIS_MODULE, + .cra_ctxsize = sizeof(struct atmel_ecdh_ctx), + }, +}; + +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; + 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; + } + + ret = of_property_read_u32(client->adapter->dev.of_node, + "clock-frequency", &bus_clk_rate); + if (ret) { + dev_err(dev, "of: 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); + if (ret) + return ret; + + spin_lock(&driver_data.i2c_list_lock); + list_add_tail(&i2c_priv->i2c_client_list_node, + &driver_data.i2c_client_list); + spin_unlock(&driver_data.i2c_list_lock); + + ret = crypto_register_kpp(&atmel_ecdh); + if (ret) { + spin_lock(&driver_data.i2c_list_lock); + list_del(&i2c_priv->i2c_client_list_node); + spin_unlock(&driver_data.i2c_list_lock); + + dev_err(dev, "%s alg registration failed\n", + atmel_ecdh.base.cra_driver_name); + } else { + dev_info(dev, "atmel ecc algorithms registered in /proc/crypto\n"); + } + + return ret; +} + +static int atmel_ecc_remove(struct i2c_client *client) +{ + struct atmel_ecc_i2c_client_priv *i2c_priv = i2c_get_clientdata(client); + + /* Return EBUSY if i2c client already allocated. */ + if (atomic_read(&i2c_priv->tfm_count)) { + dev_err(&client->dev, "Device is busy\n"); + return -EBUSY; + } + + crypto_unregister_kpp(&atmel_ecdh); + + spin_lock(&driver_data.i2c_list_lock); + list_del(&i2c_priv->i2c_client_list_node); + spin_unlock(&driver_data.i2c_list_lock); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id atmel_ecc_dt_ids[] = { + { + .compatible = "atmel,atecc508a", + }, { + /* sentinel */ + } +}; +MODULE_DEVICE_TABLE(of, atmel_ecc_dt_ids); +#endif + +static const struct i2c_device_id atmel_ecc_id[] = { + { "atecc508a", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, atmel_ecc_id); + +static struct i2c_driver atmel_ecc_driver = { + .driver = { + .name = "atmel-ecc", + .of_match_table = of_match_ptr(atmel_ecc_dt_ids), + }, + .probe = atmel_ecc_probe, + .remove = atmel_ecc_remove, + .id_table = atmel_ecc_id, +}; + +static int __init atmel_ecc_init(void) +{ + spin_lock_init(&driver_data.i2c_list_lock); + INIT_LIST_HEAD(&driver_data.i2c_client_list); + return i2c_add_driver(&atmel_ecc_driver); +} + +static void __exit atmel_ecc_exit(void) +{ + flush_scheduled_work(); + i2c_del_driver(&atmel_ecc_driver); +} + +module_init(atmel_ecc_init); +module_exit(atmel_ecc_exit); + +MODULE_AUTHOR("Tudor Ambarus <tudor.ambarus@microchip.com>"); +MODULE_DESCRIPTION("Microchip / Atmel ECC (I2C) driver"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/crypto/atmel-ecc.h b/drivers/crypto/atmel-ecc.h new file mode 100644 index 000000000000..25232c8abcc2 --- /dev/null +++ b/drivers/crypto/atmel-ecc.h @@ -0,0 +1,128 @@ +/* + * Copyright (c) 2017, Microchip Technology Inc. + * Author: Tudor Ambarus <tudor.ambarus@microchip.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#ifndef __ATMEL_ECC_H__ +#define __ATMEL_ECC_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 MAX_RSP_SIZE GENKEY_RSP_SIZE + +/** + * atmel_ecc_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_ecc_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 + +/* Command opcode */ +#define OPCODE_ECDH 0x43 +#define OPCODE_GENKEY 0x40 +#define OPCODE_READ 0x02 + +/* Definitions for the READ Command */ +#define READ_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 + +#endif /* __ATMEL_ECC_H__ */ |