mei: make mei_write_message more readable

1. reduce hairy casting
2. replace open code with mei_count_empty_write_slots
4. include header size in check for overflow
3. use concise for loop instead of a while loop

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 18 insertions, 31 deletions

diff --git a/drivers/misc/mei/interface.c b/drivers/misc/mei/interface.c
index 428d21e36416..6c0569177646 100644
--- a/drivers/misc/mei/interface.c
+++ b/drivers/misc/mei/interface.c
@@ -127,52 +127,39 @@ int mei_count_empty_write_slots(struct mei_device *dev)
  *
  * This function returns -EIO if write has failed
  */
-int mei_write_message(struct mei_device *dev,
-                      struct mei_msg_hdr *header,
-                      unsigned char *write_buffer,
-                      unsigned long write_length)
+int mei_write_message(struct mei_device *dev, struct mei_msg_hdr *header,
+                      unsigned char *buf, unsigned long length)
 {
-        u32 temp_msg = 0;
-        unsigned long bytes_written = 0;
-        unsigned char buffer_depth, filled_slots, empty_slots;
-        unsigned long dw_to_write;
-
-        dev->host_hw_state = mei_hcsr_read(dev);
+        unsigned long rem, dw_cnt;
+        u32 *reg_buf = (u32 *)buf;
+        int i;
+        int empty_slots;
 
-        dev_dbg(&dev->pdev->dev,
-                        "host_hw_state = 0x%08x.\n",
-                        dev->host_hw_state);
 
         dev_dbg(&dev->pdev->dev,
                         "mei_write_message header=%08x.\n",
                         *((u32 *) header));
 
-        buffer_depth = (unsigned char) ((dev->host_hw_state & H_CBD) >> 24);
-        filled_slots = _host_get_filled_slots(dev);
-        empty_slots = buffer_depth - filled_slots;
-        dev_dbg(&dev->pdev->dev,
-                        "filled = %hu, empty = %hu.\n",
-                        filled_slots, empty_slots);
-
-        dw_to_write = ((write_length + 3) / 4);
+        empty_slots = mei_count_empty_write_slots(dev);
+        dev_dbg(&dev->pdev->dev, "empty slots = %hu.\n", empty_slots);
 
-        if (dw_to_write > empty_slots)
+        dw_cnt = (length + sizeof(*header) + 3) / 4;
+        if (empty_slots < 0 || dw_cnt > empty_slots)
                 return -EIO;
 
         mei_reg_write(dev, H_CB_WW, *((u32 *) header));
 
-        while (write_length >= 4) {
-                mei_reg_write(dev, H_CB_WW,
-                                *(u32 *) (write_buffer + bytes_written));
-                bytes_written += 4;
-                write_length -= 4;
-        }
+        for (i = 0; i < length / 4; i++)
+                mei_reg_write(dev, H_CB_WW, reg_buf[i]);
 
-        if (write_length > 0) {
-                memcpy(&temp_msg, &write_buffer[bytes_written], write_length);
-                mei_reg_write(dev, H_CB_WW, temp_msg);
+        rem = length & 0x3;
+        if (rem > 0) {
+                u32 reg = 0;
+                memcpy(&reg, &buf[length - rem], rem);
+                mei_reg_write(dev, H_CB_WW, reg);
         }
 
+        dev->host_hw_state = mei_hcsr_read(dev);
         dev->host_hw_state |= H_IG;
         mei_hcsr_set(dev);
         dev->me_hw_state = mei_mecsr_read(dev);