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
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/
* 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 <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
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)
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)
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;
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;
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);
{
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;
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;
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;
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);
}
},
};
-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);
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;
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)) {
+++ /dev/null
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright (c) 2017, Microchip Technology Inc.
- * Author: Tudor Ambarus <tudor.ambarus@microchip.com>
- */
-
-#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__ */
--- /dev/null
+// 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");
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2017, Microchip Technology Inc.
+ * Author: Tudor Ambarus <tudor.ambarus@microchip.com>
+ */
+
+#ifndef __ATMEL_I2C_H__
+#define __ATMEL_I2C_H__
+
+#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_i2c_cmd - structure used for communicating with the device.
+ * @word_addr: indicates the function of the packet sent to the device. This
+ * byte should have a value of COMMAND for normal operation.
+ * @count : number of bytes to be transferred to (or from) the device.
+ * @opcode : the command code.
+ * @param1 : the first parameter; always present.
+ * @param2 : the second parameter; always present.
+ * @data : optional remaining input data. Includes a 2-byte CRC.
+ * @rxsize : size of the data received from i2c client.
+ * @msecs : command execution time in milliseconds
+ */
+struct atmel_i2c_cmd {
+ u8 word_addr;
+ u8 count;
+ u8 opcode;
+ u8 param1;
+ u16 param2;
+ u8 data[MAX_RSP_SIZE];
+ u8 msecs;
+ u16 rxsize;
+} __packed;
+
+/* Status/Error codes */
+#define STATUS_SIZE 0x04
+#define STATUS_NOERR 0x00
+#define STATUS_WAKE_SUCCESSFUL 0x11
+
+static const struct {
+ u8 value;
+ const char *error_text;
+} error_list[] = {
+ { 0x01, "CheckMac or Verify miscompare" },
+ { 0x03, "Parse Error" },
+ { 0x05, "ECC Fault" },
+ { 0x0F, "Execution Error" },
+ { 0xEE, "Watchdog about to expire" },
+ { 0xFF, "CRC or other communication error" },
+};
+
+/* Definitions for eeprom organization */
+#define CONFIG_ZONE 0
+
+/* Definitions for Indexes common to all commands */
+#define RSP_DATA_IDX 1 /* buffer index of data in response */
+#define DATA_SLOT_2 2 /* used for ECDH private key */
+
+/* Definitions for the device lock state */
+#define DEVICE_LOCK_ADDR 0x15
+#define LOCK_VALUE_IDX (RSP_DATA_IDX + 2)
+#define LOCK_CONFIG_IDX (RSP_DATA_IDX + 3)
+
+/*
+ * Wake High delay to data communication (microseconds). SDA should be stable
+ * high for this entire duration.
+ */
+#define TWHI_MIN 1500
+#define TWHI_MAX 1550
+
+/* Wake Low duration */
+#define TWLO_USEC 60
+
+/* Command execution time (milliseconds) */
+#define MAX_EXEC_TIME_ECDH 58
+#define MAX_EXEC_TIME_GENKEY 115
+#define MAX_EXEC_TIME_READ 1
+
+/* 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
+
+/* 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__ */
projects / openwrt / staging / blogic.git / commitdiff