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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2019-05-24 18:26:48 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2019-05-30 09:35:45 +0200
commitc34a320176a59445d76783e5ee043d6ecd22d011 (patch)
treebfd1e21b2b68dad8d2f213b9a7b59c70bde84e81 /drivers/crypto/atmel-i2c.h
parentcrypto: atmel-ecc - add support for ACPI probing on non-AT91 platforms (diff)
downloadlinux-c34a320176a59445d76783e5ee043d6ecd22d011.tar.xz
linux-c34a320176a59445d76783e5ee043d6ecd22d011.zip
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>
Diffstat (limited to 'drivers/crypto/atmel-i2c.h')
-rw-r--r--drivers/crypto/atmel-i2c.h186
1 files changed, 186 insertions, 0 deletions
diff --git a/drivers/crypto/atmel-i2c.h b/drivers/crypto/atmel-i2c.h
new file mode 100644
index 000000000000..82de5166acfa
--- /dev/null
+++ b/drivers/crypto/atmel-i2c.h
@@ -0,0 +1,186 @@
+/* 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__ */