crypto: atmel-sha204a - add reading from otp zone

Provide a read function reading the otp zone. The otp zone can be used for
storing serial numbers. The otp zone, as also data zone, are only
accessible if the chip was locked before. Locking the chip is a post
production customization and has to be done manually i.e. not by this
driver. Without this step the chip is pretty much not usable, where
putting or not putting data into the otp zone is optional.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/atmel-i2c.c b/drivers/crypto/atmel-i2c.c
index a0d0d4f2ab25aa6a58f58b3a5a239a19f52d6a5b..a895e4289efa0c89b0554883334b585be046d7ba 100644 (file)
--- a/drivers/crypto/atmel-i2c.c
+++ b/drivers/crypto/atmel-i2c.c
@@ -70,6 +70,30 @@ void atmel_i2c_init_read_config_cmd(struct atmel_i2c_cmd *cmd)
 }
 EXPORT_SYMBOL(atmel_i2c_init_read_config_cmd);
 
+int atmel_i2c_init_read_otp_cmd(struct atmel_i2c_cmd *cmd, u16 addr)
+{
+       if (addr < 0 || addr > OTP_ZONE_SIZE)
+               return -1;
+
+       cmd->word_addr = COMMAND;
+       cmd->opcode = OPCODE_READ;
+       /*
+        * Read the word from OTP zone that may contain e.g. serial
+        * numbers or similar if persistently pre-initialized and locked
+        */
+       cmd->param1 = OTP_ZONE;
+       cmd->param2 = cpu_to_le16(addr);
+       cmd->count = READ_COUNT;
+
+       atmel_i2c_checksum(cmd);
+
+       cmd->msecs = MAX_EXEC_TIME_READ;
+       cmd->rxsize = READ_RSP_SIZE;
+
+       return 0;
+}
+EXPORT_SYMBOL(atmel_i2c_init_read_otp_cmd);
+
 void atmel_i2c_init_random_cmd(struct atmel_i2c_cmd *cmd)
 {
        cmd->word_addr = COMMAND;

diff --git a/drivers/crypto/atmel-i2c.h b/drivers/crypto/atmel-i2c.h
index 275297a8208bba795b57a066ab53feff8c757ad5..72f04c15682ffee42137b57546579aa476d158bb 100644 (file)
--- a/drivers/crypto/atmel-i2c.h
+++ b/drivers/crypto/atmel-i2c.h
@@ -64,6 +64,10 @@ struct atmel_i2c_cmd {
 
 /* Definitions for eeprom organization */
 #define CONFIGURATION_ZONE             0
+#define OTP_ZONE                       1
+
+/* Definitions for eeprom zone sizes */
+#define OTP_ZONE_SIZE                  64
 
 /* Definitions for Indexes common to all commands */
 #define RSP_DATA_IDX                   1 /* buffer index of data in response */
@@ -179,6 +183,7 @@ void atmel_i2c_flush_queue(void);
 int atmel_i2c_send_receive(struct i2c_client *client, struct atmel_i2c_cmd *cmd);
 
 void atmel_i2c_init_read_config_cmd(struct atmel_i2c_cmd *cmd);
+int atmel_i2c_init_read_otp_cmd(struct atmel_i2c_cmd *cmd, u16 addr);
 void atmel_i2c_init_random_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,

diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c
index c77f482d2a97e905f453cdd7b5cc77f6cb36122f..563a0493b492037bfa7b9ba6fe6dd43f944b5c16 100644 (file)
--- a/drivers/crypto/atmel-sha204a.c
+++ b/drivers/crypto/atmel-sha204a.c
@@ -91,6 +91,29 @@ static int atmel_sha204a_rng_read(struct hwrng *rng, void *data, size_t max,
        return max;
 }
 
+static int atmel_sha204a_otp_read(struct i2c_client *client, u16 addr, u8 *otp)
+{
+       struct atmel_i2c_cmd cmd;
+       int ret = -1;
+
+       if (atmel_i2c_init_read_otp_cmd(&cmd, addr) < 0) {
+               dev_err(&client->dev, "failed, invalid otp address %04X\n",
+                       addr);
+               return ret;
+       }
+
+       ret = atmel_i2c_send_receive(client, &cmd);
+
+       if (cmd.data[0] == 0xff) {
+               dev_err(&client->dev, "failed, device not ready\n");
+               return -ret;
+       }
+
+       memcpy(otp, cmd.data+1, 4);
+
+       return ret;
+}
+
 static int atmel_sha204a_probe(struct i2c_client *client)
 {
        struct atmel_i2c_client_priv *i2c_priv;