crypto: atmel-ecc - factor out code that can be shared

In preparation of adding support for the random number generator in
Atmel atsha204a devices, refactor the existing atmel-ecc driver (which
drives hardware that is closely related) so we can share the basic
I2C and command queuing routines.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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__ */