mei: constify buffer in the write functions calls

The write buffer should not by modified so make it constant. Also
hitchhike some style fixes on the way in the interface and rename
mei_me_write_message to mei_me_hbuf_write for consistency.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hw-me.c

@@ -450,7 +450,7 @@ static size_t mei_me_hbuf_max_len(const struct mei_device *dev)
 
 
 /**
- * mei_me_write_message - writes a message to mei device.
+ * mei_me_hbuf_write - writes a message to host hw buffer.
  *
  * @dev: the device structure
  * @header: mei HECI header of message
@@ -458,9 +458,9 @@ static size_t mei_me_hbuf_max_len(const struct mei_device *dev)
  *
  * Return: -EIO if write has failed
  */
-static int mei_me_write_message(struct mei_device *dev,
-			struct mei_msg_hdr *header,
-			unsigned char *buf)
+static int mei_me_hbuf_write(struct mei_device *dev,
+			     struct mei_msg_hdr *header,
+			     const unsigned char *buf)
 {
 	unsigned long rem;
 	unsigned long length = header->length;
@@ -1243,7 +1243,7 @@ static const struct mei_hw_ops mei_me_hw_ops = {
 	.hbuf_is_ready = mei_me_hbuf_is_empty,
 	.hbuf_max_len = mei_me_hbuf_max_len,
 
-	.write = mei_me_write_message,
+	.write = mei_me_hbuf_write,
 
 	.rdbuf_full_slots = mei_me_count_full_read_slots,
 	.read_hdr = mei_me_mecbrw_read,

drivers/misc/mei/hw-txe.c

@@ -691,7 +691,8 @@ static void mei_txe_hw_config(struct mei_device *dev)
  */
 
 static int mei_txe_write(struct mei_device *dev,
-		struct mei_msg_hdr *header, unsigned char *buf)
+			 struct mei_msg_hdr *header,
+			 const unsigned char *buf)
 {
 	struct mei_txe_hw *hw = to_txe_hw(dev);
 	unsigned long rem;

drivers/misc/mei/mei_dev.h

@@ -300,10 +300,9 @@ struct mei_hw_ops {
 	int (*hbuf_free_slots)(struct mei_device *dev);
 	bool (*hbuf_is_ready)(struct mei_device *dev);
 	size_t (*hbuf_max_len)(const struct mei_device *dev);
-
 	int (*write)(struct mei_device *dev,
 		     struct mei_msg_hdr *hdr,
-		     unsigned char *buf);
+		     const unsigned char *buf);
 
 	int (*rdbuf_full_slots)(struct mei_device *dev);
 
@@ -665,7 +664,7 @@ static inline size_t mei_hbuf_max_len(const struct mei_device *dev)
 }
 
 static inline int mei_write_message(struct mei_device *dev,
-			struct mei_msg_hdr *hdr, void *buf)
+				    struct mei_msg_hdr *hdr, const void *buf)
 {
 	return dev->ops->write(dev, hdr, buf);
 }