mei: use structured buffer for extra write buffer

The structure of the message is static so we don't have
to use and cast the buffer. We can also drop extra_write_index
variable as this information can be extracted directly
from the message header

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

drivers/misc/mei/init.c

@@ -288,7 +288,7 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
 		mei_me_cl_unlink(dev, &dev->iamthif_cl);
 
 		mei_amthif_reset_params(dev);
-		dev->extra_write_index = 0;
+		memset(&dev->wr_ext_msg, 0, sizeof(dev->wr_ext_msg));
 	}
 
 	dev->me_clients_num = 0;

drivers/misc/mei/interrupt.c

@@ -446,15 +446,14 @@ static void mei_client_disconnect_request(struct mei_device *dev,
 				dev->iamthif_timer = 0;
 
 			/* prepare disconnect response */
-			(void)mei_hbm_hdr(&dev->ext_msg_buf[0], len);
+			(void)mei_hbm_hdr((u32 *)&dev->wr_ext_msg.hdr, len);
 			disconnect_res =
 				(struct hbm_client_connect_response *)
-				&dev->ext_msg_buf[1];
+				&dev->wr_ext_msg.data;
 			disconnect_res->hbm_cmd = CLIENT_DISCONNECT_RES_CMD;
 			disconnect_res->host_addr = pos->host_client_id;
 			disconnect_res->me_addr = pos->me_client_id;
 			disconnect_res->status = 0;
-			dev->extra_write_index = 2;
 			break;
 		}
 	}
@@ -643,16 +642,13 @@ static void mei_irq_thread_read_bus_message(struct mei_device *dev,
 	{
 		/* prepare stop request: sent in next interrupt event */
 
-		u32 *buf = dev->ext_msg_buf;
 		const size_t len = sizeof(struct hbm_host_stop_request);
 
-		mei_hdr = mei_hbm_hdr(&buf[0], len);
-		stop_req = (struct hbm_host_stop_request *)&buf[1];
+		mei_hdr = mei_hbm_hdr((u32 *)&dev->wr_ext_msg.hdr, len);
+		stop_req = (struct hbm_host_stop_request *)&dev->wr_ext_msg.data;
 		memset(stop_req, 0, len);
 		stop_req->hbm_cmd = HOST_STOP_REQ_CMD;
 		stop_req->reason = DRIVER_STOP_REQUEST;
-
-		dev->extra_write_index = 2;
 		break;
 	}
 	default:
@@ -988,15 +984,11 @@ static int mei_irq_thread_write_handler(struct mei_cl_cb *cmpl_list,
 		wake_up_interruptible(&dev->wait_stop_wd);
 	}
 
-	if (dev->extra_write_index) {
-		dev_dbg(&dev->pdev->dev, "extra_write_index =%d.\n",
-				dev->extra_write_index);
-		mei_write_message(dev,
-				(struct mei_msg_hdr *) &dev->ext_msg_buf[0],
-				(unsigned char *) &dev->ext_msg_buf[1],
-				(dev->extra_write_index - 1) * sizeof(u32));
-		*slots -= dev->extra_write_index;
-		dev->extra_write_index = 0;
+	if (dev->wr_ext_msg.hdr.length) {
+		mei_write_message(dev, &dev->wr_ext_msg.hdr,
+			dev->wr_ext_msg.data, dev->wr_ext_msg.hdr.length);
+		*slots -= mei_data2slots(dev->wr_ext_msg.hdr.length);
+		dev->wr_ext_msg.hdr.length = 0;
 	}
 	if (dev->dev_state == MEI_DEV_ENABLED) {
 		if (dev->wd_pending &&
@@ -1263,11 +1255,11 @@ irqreturn_t mei_interrupt_thread_handler(int irq, void *dev_id)
 	}
 	/* check slots available for reading */
 	slots = mei_count_full_read_slots(dev);
-	dev_dbg(&dev->pdev->dev, "slots =%08x  extra_write_index =%08x.\n",
-		slots, dev->extra_write_index);
-	while (slots > 0 && !dev->extra_write_index) {
-		dev_dbg(&dev->pdev->dev, "slots =%08x  extra_write_index =%08x.\n",
-				slots, dev->extra_write_index);
+	while (slots > 0) {
+		/* we have urgent data to send so break the read */
+		if (dev->wr_ext_msg.hdr.length)
+			break;
+		dev_dbg(&dev->pdev->dev, "slots =%08x\n", slots);
 		dev_dbg(&dev->pdev->dev, "call mei_irq_thread_read_handler.\n");
 		rets = mei_irq_thread_read_handler(&complete_list, dev, &slots);
 		if (rets)

drivers/misc/mei/mei_dev.h

@@ -192,8 +192,9 @@ struct mei_cl {
 };
 
 /**
- * struct mei_deive -  MEI private device struct
+ * struct mei_device -  MEI private device struct
  * @hbuf_depth - depth of host(write) buffer
+ * @wr_ext_msg - buffer for hbm control responses (set in read cycle)
  */
 struct mei_device {
 	struct pci_dev *pdev;	/* pointer to pci device struct */
@@ -244,11 +245,13 @@ struct mei_device {
 	u16 init_clients_timer;
 	bool need_reset;
 
-	u32 extra_write_index;
 	unsigned char rd_msg_buf[MEI_RD_MSG_BUF_SIZE];	/* control messages */
-	u32 wr_msg_buf[128];	/* used for control messages */
-	u32 ext_msg_buf[8];	/* for control responses */
 	u32 rd_msg_hdr;
+	u32 wr_msg_buf[128];	/* used for control messages */
+	struct {
+		struct mei_msg_hdr hdr;
+		unsigned char data[4];	/* All HBM messages are 4 bytes */
+	} wr_ext_msg;		/* for control responses */
 
 	struct hbm_version version;