diff options
| -rw-r--r-- | drivers/crypto/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/crypto/Makefile | 1 | ||||
| -rw-r--r-- | drivers/crypto/atmel-ecc.c | 406 | ||||
| -rw-r--r-- | drivers/crypto/atmel-i2c.c | 349 | ||||
| -rw-r--r-- | drivers/crypto/atmel-i2c.h (renamed from drivers/crypto/atmel-ecc.h) | 80 |
5 files changed, 451 insertions, 389 deletions
diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig index 119ba073f424..20674842261e 100644 --- a/drivers/crypto/Kconfig +++ b/drivers/crypto/Kconfig @@ -519,9 +519,13 @@ 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_I2C + tristate + config CRYPTO_DEV_ATMEL_ECC tristate "Support for Microchip / Atmel ECC hw accelerator" depends on I2C + select CRYPTO_DEV_ATMEL_I2C select CRYPTO_ECDH select CRC16 help diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile index a23a7197fcd7..394e84089924 100644 --- a/drivers/crypto/Makefile +++ b/drivers/crypto/Makefile @@ -2,6 +2,7 @@ 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_I2C) += atmel-i2c.o obj-$(CONFIG_CRYPTO_DEV_ATMEL_ECC) += atmel-ecc.o obj-$(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 index 5705348f540f..ff02cc05affb 100644 --- a/drivers/crypto/atmel-ecc.c +++ b/drivers/crypto/atmel-ecc.c @@ -6,8 +6,6 @@ * 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> @@ -23,42 +21,11 @@ #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; +#include "atmel-i2c.h" 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 @@ -80,188 +47,12 @@ struct atmel_ecdh_ctx { 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 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_ecc_work_data { - struct atmel_ecdh_ctx *ctx; - void (*cbk)(struct atmel_ecc_work_data *work_data, void *areq, - int 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, - sg_nents_for_len(pubkey, - ATMEL_ECC_PUBKEY_SIZE), - 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, +static void atmel_ecdh_done(struct atmel_i2c_work_data *work_data, void *areq, int status) { struct kpp_request *req = areq; struct atmel_ecdh_ctx *ctx = work_data->ctx; - struct atmel_ecc_cmd *cmd = &work_data->cmd; + struct atmel_i2c_cmd *cmd = &work_data->cmd; size_t copied, n_sz; if (status) @@ -282,82 +73,6 @@ free_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; - int 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, int 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) @@ -374,7 +89,7 @@ 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; + struct atmel_i2c_cmd *cmd; void *public_key; struct ecdh params; int ret = -ENOMEM; @@ -412,9 +127,9 @@ static int atmel_ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, ctx->do_fallback = false; ctx->curve_id = params.curve_id; - atmel_ecc_init_genkey_cmd(cmd, DATA_SLOT_2); + atmel_i2c_init_genkey_cmd(cmd, DATA_SLOT_2); - ret = atmel_ecc_send_receive(ctx->client, cmd); + ret = atmel_i2c_send_receive(ctx->client, cmd); if (ret) goto free_public_key; @@ -444,6 +159,9 @@ static int atmel_ecdh_generate_public_key(struct kpp_request *req) return crypto_kpp_generate_public_key(req); } + if (!ctx->public_key) + return -EINVAL; + /* might want less than we've got */ nbytes = min_t(size_t, ATMEL_ECC_PUBKEY_SIZE, req->dst_len); @@ -461,7 +179,7 @@ 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; + struct atmel_i2c_work_data *work_data; gfp_t gfp; int ret; @@ -482,12 +200,13 @@ static int atmel_ecdh_compute_shared_secret(struct kpp_request *req) return -ENOMEM; work_data->ctx = ctx; + work_data->client = ctx->client; - ret = atmel_ecc_init_ecdh_cmd(&work_data->cmd, req->src); + ret = atmel_i2c_init_ecdh_cmd(&work_data->cmd, req->src); if (ret) goto free_work_data; - atmel_ecc_enqueue(work_data, atmel_ecdh_done, req); + atmel_i2c_enqueue(work_data, atmel_ecdh_done, req); return -EINPROGRESS; @@ -498,7 +217,7 @@ free_work_data: static struct i2c_client *atmel_ecc_i2c_client_alloc(void) { - struct atmel_ecc_i2c_client_priv *i2c_priv, *min_i2c_priv = NULL; + struct atmel_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; @@ -533,7 +252,7 @@ static struct i2c_client *atmel_ecc_i2c_client_alloc(void) static void atmel_ecc_i2c_client_free(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); atomic_dec(&i2c_priv->tfm_count); } @@ -604,99 +323,18 @@ static struct kpp_alg atmel_ecdh = { }, }; -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)) { diff --git a/drivers/crypto/atmel-i2c.c b/drivers/crypto/atmel-i2c.c new file mode 100644 index 000000000000..5e099368d120 --- /dev/null +++ b/drivers/crypto/atmel-i2c.c @@ -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"); diff --git a/drivers/crypto/atmel-ecc.h b/drivers/crypto/atmel-i2c.h index 643a3b947338..82de5166acfa 100644 --- a/drivers/crypto/atmel-ecc.h +++ b/drivers/crypto/atmel-i2c.h @@ -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__ */ |