tpm: fix buffer type in tpm_transmit_cmd

1. The buffer cannot be const as it is used both for send and receive.
2. Drop useless casting to u8 *, as this is already a
type of 'buf' parameter, it has just masked the 'const' issue.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/tpm-interface.c

@@ -473,7 +473,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	if (rc)
 		goto out;
 
-	rc = chip->ops->send(chip, (u8 *) buf, count);
+	rc = chip->ops->send(chip, buf, count);
 	if (rc < 0) {
 		if (rc != -EPIPE)
 			dev_err(&chip->dev,
@@ -510,7 +510,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	goto out;
 
 out_recv:
-	len = chip->ops->recv(chip, (u8 *) buf, bufsiz);
+	len = chip->ops->recv(chip, buf, bufsiz);
 	if (len < 0) {
 		rc = len;
 		dev_err(&chip->dev,
@@ -562,7 +562,7 @@ out_no_locality:
  *     A positive number for a TPM error.
  */
 ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
-			 const void *buf, size_t bufsiz,
+			 void *buf, size_t bufsiz,
 			 size_t min_rsp_body_length, unsigned int flags,
 			 const char *desc)
 {
@@ -570,7 +570,7 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
 	int err;
 	ssize_t len;
 
-	len = tpm_transmit(chip, space, (u8 *)buf, bufsiz, flags);
+	len = tpm_transmit(chip, space, buf, bufsiz, flags);
 	if (len <  0)
 		return len;
 

drivers/char/tpm/tpm.h

@@ -506,7 +506,7 @@ enum tpm_transmit_flags {
 ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 		     u8 *buf, size_t bufsiz, unsigned int flags);
 ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
-			 const void *buf, size_t bufsiz,
+			 void *buf, size_t bufsiz,
 			 size_t min_rsp_body_length, unsigned int flags,
 			 const char *desc);
 int tpm_startup(struct tpm_chip *chip);