8 files changed, 150 insertions, 227 deletions

diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index a7d0bb0880ec..e77f86e69fb5 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -162,6 +162,9 @@ int mei_hw_init(struct mei_device *dev)
 	if ((dev->host_hw_state & H_IS) == H_IS)
 		mei_reg_write(dev, H_CSR, dev->host_hw_state);
 
+	/* Doesn't change in runtime */
+	dev->hbuf_depth = (dev->host_hw_state & H_CBD) >> 24;
+
 	dev->recvd_msg = false;
 	dev_dbg(&dev->pdev->dev, "reset in start the mei device.\n");
 
@@ -303,7 +306,6 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
 				dev->iamthif_cl.host_client_id);
 
 		mei_reset_iamthif_params(dev);
-		dev->wd_due_counter = 0;
 		dev->extra_write_index = 0;
 	}
 
diff --git a/drivers/misc/mei/interface.c b/drivers/misc/mei/interface.c
index 428d21e36416..509c3957ff45 100644
--- a/drivers/misc/mei/interface.c
+++ b/drivers/misc/mei/interface.c
@@ -58,16 +58,18 @@ void mei_disable_interrupts(struct mei_device *dev)
 }
 
 /**
- * _host_get_filled_slots - gets number of device filled buffer slots
+ * mei_hbuf_filled_slots - gets number of device filled buffer slots
  *
  * @device: the device structure
  *
  * returns number of filled slots
  */
-static unsigned char _host_get_filled_slots(const struct mei_device *dev)
+static unsigned char mei_hbuf_filled_slots(struct mei_device *dev)
 {
 	char read_ptr, write_ptr;
 
+	dev->host_hw_state = mei_hcsr_read(dev);
+
 	read_ptr = (char) ((dev->host_hw_state & H_CBRP) >> 8);
 	write_ptr = (char) ((dev->host_hw_state & H_CBWP) >> 16);
 
@@ -75,43 +77,33 @@ static unsigned char _host_get_filled_slots(const struct mei_device *dev)
 }
 
 /**
- * mei_host_buffer_is_empty - checks if host buffer is empty.
+ * mei_hbuf_is_empty - checks if host buffer is empty.
  *
  * @dev: the device structure
  *
- * returns 1 if empty, 0 - otherwise.
+ * returns true if empty, false - otherwise.
  */
-int mei_host_buffer_is_empty(struct mei_device *dev)
+bool mei_hbuf_is_empty(struct mei_device *dev)
 {
-	unsigned char filled_slots;
-
-	dev->host_hw_state = mei_hcsr_read(dev);
-	filled_slots = _host_get_filled_slots(dev);
-
-	if (filled_slots == 0)
-		return 1;
-
-	return 0;
+	return mei_hbuf_filled_slots(dev) == 0;
 }
 
 /**
- * mei_count_empty_write_slots - counts write empty slots.
+ * mei_hbuf_empty_slots - counts write empty slots.
  *
  * @dev: the device structure
  *
  * returns -1(ESLOTS_OVERFLOW) if overflow, otherwise empty slots count
  */
-int mei_count_empty_write_slots(struct mei_device *dev)
+int mei_hbuf_empty_slots(struct mei_device *dev)
 {
-	unsigned char buffer_depth, filled_slots, empty_slots;
+	unsigned char filled_slots, empty_slots;
 
-	dev->host_hw_state = mei_hcsr_read(dev);
-	buffer_depth = (unsigned char) ((dev->host_hw_state & H_CBD) >> 24);
-	filled_slots = _host_get_filled_slots(dev);
-	empty_slots = buffer_depth - filled_slots;
+	filled_slots = mei_hbuf_filled_slots(dev);
+	empty_slots = dev->hbuf_depth - filled_slots;
 
 	/* check for overflow */
-	if (filled_slots > buffer_depth)
+	if (filled_slots > dev->hbuf_depth)
 		return -EOVERFLOW;
 
 	return empty_slots;
@@ -127,52 +119,39 @@ 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_hbuf_empty_slots(dev);
+	dev_dbg(&dev->pdev->dev, "empty slots = %hu.\n", empty_slots);
 
-	if (dw_to_write > empty_slots)
+	dw_cnt = mei_data2slots(length);
+	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);
diff --git a/drivers/misc/mei/interface.h b/drivers/misc/mei/interface.h
index ddff5d16616f..fb5c7db4723b 100644
--- a/drivers/misc/mei/interface.h
+++ b/drivers/misc/mei/interface.h
@@ -41,14 +41,28 @@ int mei_write_message(struct mei_device *dev,
 			     unsigned char *write_buffer,
 			     unsigned long write_length);
 
-int mei_host_buffer_is_empty(struct mei_device *dev);
+bool mei_hbuf_is_empty(struct mei_device *dev);
+
+int mei_hbuf_empty_slots(struct mei_device *dev);
+
+static inline size_t mei_hbuf_max_data(const struct mei_device *dev)
+{
+	return dev->hbuf_depth * sizeof(u32) - sizeof(struct mei_msg_hdr);
+}
+
+/* get slots (dwords) from a message length + header (bytes) */
+static inline unsigned char mei_data2slots(size_t length)
+{
+	return DIV_ROUND_UP(sizeof(struct mei_msg_hdr) + length, 4);
+}
 
 int mei_count_full_read_slots(struct mei_device *dev);
 
-int mei_count_empty_write_slots(struct mei_device *dev);
 
 int mei_flow_ctrl_creds(struct mei_device *dev, struct mei_cl *cl);
 
+
+
 int mei_wd_send(struct mei_device *dev);
 int mei_wd_stop(struct mei_device *dev, bool preserve);
 int mei_wd_host_init(struct mei_device *dev);
diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 93936f1b75eb..c6ffbbe5a6c0 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -267,8 +267,7 @@ static int _mei_irq_thread_iamthif_read(struct mei_device *dev, s32 *slots)
 			+ sizeof(struct hbm_flow_control))) {
 		return -EMSGSIZE;
 	}
-	*slots -= (sizeof(struct mei_msg_hdr) +
-				sizeof(struct hbm_flow_control) + 3) / 4;
+	*slots -= mei_data2slots(sizeof(struct hbm_flow_control));
 	if (mei_send_flow_control(dev, &dev->iamthif_cl)) {
 		dev_dbg(&dev->pdev->dev, "iamthif flow control failed\n");
 		return -EIO;
@@ -280,7 +279,7 @@ static int _mei_irq_thread_iamthif_read(struct mei_device *dev, s32 *slots)
 	dev->iamthif_msg_buf_index = 0;
 	dev->iamthif_msg_buf_size = 0;
 	dev->iamthif_stall_timer = IAMTHIF_STALL_TIMER;
-	dev->mei_host_buffer_is_empty = mei_host_buffer_is_empty(dev);
+	dev->mei_host_buffer_is_empty = mei_hbuf_is_empty(dev);
 	return 0;
 }
 
@@ -300,28 +299,25 @@ static int _mei_irq_thread_close(struct mei_device *dev, s32 *slots,
 				struct mei_cl *cl,
 				struct mei_io_list *cmpl_list)
 {
-	if ((*slots * sizeof(u32)) >= (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_client_disconnect_request))) {
-		*slots -= (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_client_disconnect_request) + 3) / 4;
+	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
+			sizeof(struct hbm_client_disconnect_request)))
+		return -EBADMSG;
 
-		if (mei_disconnect(dev, cl)) {
-			cl->status = 0;
-			cb_pos->information = 0;
-			list_move_tail(&cb_pos->cb_list,
-					&cmpl_list->mei_cb.cb_list);
-			return -EMSGSIZE;
-		} else {
-			cl->state = MEI_FILE_DISCONNECTING;
-			cl->status = 0;
-			cb_pos->information = 0;
-			list_move_tail(&cb_pos->cb_list,
-					&dev->ctrl_rd_list.mei_cb.cb_list);
-			cl->timer_count = MEI_CONNECT_TIMEOUT;
-		}
+	*slots -= mei_data2slots(sizeof(struct hbm_client_disconnect_request));
+
+	if (mei_disconnect(dev, cl)) {
+		cl->status = 0;
+		cb_pos->information = 0;
+		list_move_tail(&cb_pos->cb_list,
+				&cmpl_list->mei_cb.cb_list);
+		return -EMSGSIZE;
 	} else {
-		/* return the cancel routine */
-		return -EBADMSG;
+		cl->state = MEI_FILE_DISCONNECTING;
+		cl->status = 0;
+		cb_pos->information = 0;
+		list_move_tail(&cb_pos->cb_list,
+				&dev->ctrl_rd_list.mei_cb.cb_list);
+		cl->timer_count = MEI_CONNECT_TIMEOUT;
 	}
 
 	return 0;
@@ -575,10 +571,9 @@ static void mei_client_disconnect_request(struct mei_device *dev,
 					disconnect_req->me_addr);
 			cl_pos->state = MEI_FILE_DISCONNECTED;
 			cl_pos->timer_count = 0;
-			if (cl_pos == &dev->wd_cl) {
-				dev->wd_due_counter = 0;
+			if (cl_pos == &dev->wd_cl)
 				dev->wd_pending = false;
-			} else if (cl_pos == &dev->iamthif_cl)
+			else if (cl_pos == &dev->iamthif_cl)
 				dev->iamthif_timer = 0;
 
 			/* prepare disconnect response */
@@ -835,15 +830,15 @@ static int _mei_irq_thread_read(struct mei_device *dev,	s32 *slots,
 			struct mei_cl *cl,
 			struct mei_io_list *cmpl_list)
 {
-	if ((*slots * sizeof(u32)) >= (sizeof(struct mei_msg_hdr) +
+	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
 			sizeof(struct hbm_flow_control))) {
 		/* return the cancel routine */
 		list_del(&cb_pos->cb_list);
 		return -EBADMSG;
 	}
 
-	*slots -= (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_flow_control) + 3) / 4;
+	*slots -= mei_data2slots(sizeof(struct hbm_flow_control));
+
 	if (mei_send_flow_control(dev, cl)) {
 		cl->status = -ENODEV;
 		cb_pos->information = 0;
@@ -872,27 +867,25 @@ static int _mei_irq_thread_ioctl(struct mei_device *dev, s32 *slots,
 			struct mei_cl *cl,
 			struct mei_io_list *cmpl_list)
 {
-	if ((*slots * sizeof(u32)) >= (sizeof(struct mei_msg_hdr) +
+	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
 			sizeof(struct hbm_client_connect_request))) {
-		cl->state = MEI_FILE_CONNECTING;
-		*slots -= (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_client_connect_request) + 3) / 4;
-		if (mei_connect(dev, cl)) {
-			cl->status = -ENODEV;
-			cb_pos->information = 0;
-			list_del(&cb_pos->cb_list);
-			return -ENODEV;
-		} else {
-			list_move_tail(&cb_pos->cb_list,
-				&dev->ctrl_rd_list.mei_cb.cb_list);
-			cl->timer_count = MEI_CONNECT_TIMEOUT;
-		}
-	} else {
 		/* return the cancel routine */
 		list_del(&cb_pos->cb_list);
 		return -EBADMSG;
 	}
 
+	cl->state = MEI_FILE_CONNECTING;
+	 *slots -= mei_data2slots(sizeof(struct hbm_client_connect_request));
+	if (mei_connect(dev, cl)) {
+		cl->status = -ENODEV;
+		cb_pos->information = 0;
+		list_del(&cb_pos->cb_list);
+		return -ENODEV;
+	} else {
+		list_move_tail(&cb_pos->cb_list,
+			&dev->ctrl_rd_list.mei_cb.cb_list);
+		cl->timer_count = MEI_CONNECT_TIMEOUT;
+	}
 	return 0;
 }
 
@@ -932,8 +925,7 @@ static int _mei_irq_thread_cmpl(struct mei_device *dev,	s32 *slots,
 				cb_pos->information);
 		dev_dbg(&dev->pdev->dev, "mei_hdr->length  =%d\n",
 				mei_hdr->length);
-		*slots -= (sizeof(struct mei_msg_hdr) +
-				mei_hdr->length + 3) / 4;
+		*slots -= mei_data2slots(mei_hdr->length);
 		if (mei_write_message(dev, mei_hdr,
 				(unsigned char *)
 				(cb_pos->request_buffer.data +
@@ -951,7 +943,7 @@ static int _mei_irq_thread_cmpl(struct mei_device *dev,	s32 *slots,
 			list_move_tail(&cb_pos->cb_list,
 				&dev->write_waiting_list.mei_cb.cb_list);
 		}
-	} else if (*slots == ((dev->host_hw_state & H_CBD) >> 24)) {
+	} else if (*slots == dev->hbuf_depth) {
 		/* buffer is still empty */
 		mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
 		mei_hdr->host_addr = cl->host_client_id;
@@ -960,9 +952,7 @@ static int _mei_irq_thread_cmpl(struct mei_device *dev,	s32 *slots,
 			(*slots * sizeof(u32)) - sizeof(struct mei_msg_hdr);
 		mei_hdr->msg_complete = 0;
 		mei_hdr->reserved = 0;
-
-		(*slots) -= (sizeof(struct mei_msg_hdr) +
-				mei_hdr->length + 3) / 4;
+		*slots -= mei_data2slots(mei_hdr->length);
 		if (mei_write_message(dev, mei_hdr,
 					(unsigned char *)
 					(cb_pos->request_buffer.data +
@@ -1021,8 +1011,7 @@ static int _mei_irq_thread_cmpl_iamthif(struct mei_device *dev, s32 *slots,
 		mei_hdr->msg_complete = 1;
 		mei_hdr->reserved = 0;
 
-		*slots -= (sizeof(struct mei_msg_hdr) +
-				mei_hdr->length + 3) / 4;
+		*slots -= mei_data2slots(mei_hdr->length);
 
 		if (mei_write_message(dev, mei_hdr,
 					(dev->iamthif_msg_buf +
@@ -1046,8 +1035,8 @@ static int _mei_irq_thread_cmpl_iamthif(struct mei_device *dev, s32 *slots,
 				&dev->write_waiting_list.mei_cb.cb_list);
 
 		}
-	} else if (*slots == ((dev->host_hw_state & H_CBD) >> 24)) {
-			/* buffer is still empty */
+	} else if (*slots == dev->hbuf_depth) {
+		/* buffer is still empty */
 		mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
 		mei_hdr->host_addr = cl->host_client_id;
 		mei_hdr->me_addr = cl->me_client_id;
@@ -1056,8 +1045,7 @@ static int _mei_irq_thread_cmpl_iamthif(struct mei_device *dev, s32 *slots,
 		mei_hdr->msg_complete = 0;
 		mei_hdr->reserved = 0;
 
-		*slots -= (sizeof(struct mei_msg_hdr) +
-				mei_hdr->length + 3) / 4;
+		*slots -= mei_data2slots(mei_hdr->length);
 
 		if (mei_write_message(dev, mei_hdr,
 					(dev->iamthif_msg_buf +
@@ -1199,17 +1187,19 @@ static int mei_irq_thread_write_handler(struct mei_io_list *cmpl_list,
 	struct mei_io_list *list;
 	int ret;
 
-	if (!mei_host_buffer_is_empty(dev)) {
+	if (!mei_hbuf_is_empty(dev)) {
 		dev_dbg(&dev->pdev->dev, "host buffer is not empty.\n");
 		return 0;
 	}
-	*slots = mei_count_empty_write_slots(dev);
+	*slots = mei_hbuf_empty_slots(dev);
+	if (*slots <= 0)
+		return -EMSGSIZE;
+
 	/* complete all waiting for write CB */
 	dev_dbg(&dev->pdev->dev, "complete all waiting for write cb.\n");
 
 	list = &dev->write_waiting_list;
-	list_for_each_entry_safe(pos, next,
-			&list->mei_cb.cb_list, cb_list) {
+	list_for_each_entry_safe(pos, next, &list->mei_cb.cb_list, cb_list) {
 		cl = (struct mei_cl *)pos->file_private;
 		if (cl == NULL)
 			continue;
@@ -1219,17 +1209,15 @@ static int mei_irq_thread_write_handler(struct mei_io_list *cmpl_list,
 		if (MEI_WRITING == cl->writing_state &&
 		   (pos->major_file_operations == MEI_WRITE) &&
 		   (cl != &dev->iamthif_cl)) {
-			dev_dbg(&dev->pdev->dev,
-				"MEI WRITE COMPLETE\n");
+			dev_dbg(&dev->pdev->dev, "MEI WRITE COMPLETE\n");
 			cl->writing_state = MEI_WRITE_COMPLETE;
 			list_add_tail(&pos->cb_list,
-				&cmpl_list->mei_cb.cb_list);
+				      &cmpl_list->mei_cb.cb_list);
 		}
 		if (cl == &dev->iamthif_cl) {
 			dev_dbg(&dev->pdev->dev, "check iamthif flow control.\n");
 			if (dev->iamthif_flow_control_pending) {
-				ret = _mei_irq_thread_iamthif_read(
-						dev, slots);
+				ret = _mei_irq_thread_iamthif_read(dev, slots);
 				if (ret)
 					return ret;
 			}
@@ -1254,25 +1242,18 @@ static int mei_irq_thread_write_handler(struct mei_io_list *cmpl_list,
 	}
 	if (dev->mei_state == MEI_ENABLED) {
 		if (dev->wd_pending &&
-			mei_flow_ctrl_creds(dev, &dev->wd_cl) > 0) {
+		    mei_flow_ctrl_creds(dev, &dev->wd_cl) > 0) {
 			if (mei_wd_send(dev))
 				dev_dbg(&dev->pdev->dev, "wd send failed.\n");
-			else
-				if (mei_flow_ctrl_reduce(dev, &dev->wd_cl))
-					return -ENODEV;
+			else if (mei_flow_ctrl_reduce(dev, &dev->wd_cl))
+				return -ENODEV;
 
 			dev->wd_pending = false;
 
-			if (dev->wd_timeout) {
-				*slots -= (sizeof(struct mei_msg_hdr) +
-					 MEI_START_WD_DATA_SIZE + 3) / 4;
-				dev->wd_due_counter = 2;
-			} else {
-				*slots -= (sizeof(struct mei_msg_hdr) +
-					 MEI_WD_PARAMS_SIZE + 3) / 4;
-				dev->wd_due_counter = 0;
-			}
-
+			if (dev->wd_timeout)
+				*slots -= mei_data2slots(MEI_START_WD_DATA_SIZE);
+			else
+				*slots -= mei_data2slots(MEI_START_WD_DATA_SIZE);
 		}
 	}
 	if (dev->stop)
@@ -1320,42 +1301,34 @@ static int mei_irq_thread_write_handler(struct mei_io_list *cmpl_list,
 	/* complete  write list CB */
 	dev_dbg(&dev->pdev->dev, "complete write list cb.\n");
 	list_for_each_entry_safe(pos, next,
-			&dev->write_list.mei_cb.cb_list, cb_list) {
+				&dev->write_list.mei_cb.cb_list, cb_list) {
 		cl = (struct mei_cl *)pos->file_private;
 		if (cl == NULL)
 			continue;
 
 		if (cl != &dev->iamthif_cl) {
-			if (!mei_flow_ctrl_creds(dev, cl)) {
+			if (mei_flow_ctrl_creds(dev, cl) <= 0) {
 				dev_dbg(&dev->pdev->dev,
-					"No flow control"
-				    " credentials for client"
-				    " %d, not sending.\n",
-				    cl->host_client_id);
+					"No flow control credentials for client %d, not sending.\n",
+					cl->host_client_id);
 				continue;
 			}
-			ret = _mei_irq_thread_cmpl(dev, slots,
-					    pos,
-					    cl, cmpl_list);
+			ret = _mei_irq_thread_cmpl(dev, slots, pos,
+						cl, cmpl_list);
 			if (ret)
 				return ret;
 
 		} else if (cl == &dev->iamthif_cl) {
 			/* IAMTHIF IOCTL */
 			dev_dbg(&dev->pdev->dev, "complete amthi write cb.\n");
-			if (!mei_flow_ctrl_creds(dev, cl)) {
+			if (mei_flow_ctrl_creds(dev, cl) <= 0) {
 				dev_dbg(&dev->pdev->dev,
-					"No flow control"
-				    " credentials for amthi"
-				    " client %d.\n",
-				    cl->host_client_id);
+					"No flow control credentials for amthi client %d.\n",
+					cl->host_client_id);
 				continue;
 			}
-			ret = _mei_irq_thread_cmpl_iamthif(dev,
-						slots,
-						pos,
-						cl,
-						cmpl_list);
+			ret = _mei_irq_thread_cmpl_iamthif(dev, slots, pos,
+						cl, cmpl_list);
 			if (ret)
 				return ret;
 
@@ -1555,7 +1528,7 @@ irqreturn_t mei_interrupt_thread_handler(int irq, void *dev_id)
 end:
 	dev_dbg(&dev->pdev->dev, "end of bottom half function.\n");
 	dev->host_hw_state = mei_hcsr_read(dev);
-	dev->mei_host_buffer_is_empty = mei_host_buffer_is_empty(dev);
+	dev->mei_host_buffer_is_empty = mei_hbuf_is_empty(dev);
 
 	bus_message_received = false;
 	if (dev->recvd_msg && waitqueue_active(&dev->wait_recvd_msg)) {
diff --git a/drivers/misc/mei/iorw.c b/drivers/misc/mei/iorw.c
index f9cced69b65e..50f52e21f587 100644
--- a/drivers/misc/mei/iorw.c
+++ b/drivers/misc/mei/iorw.c
@@ -481,12 +481,8 @@ int amthi_write(struct mei_device *dev, struct mei_cl_cb *cb)
 	if (ret && dev->mei_host_buffer_is_empty) {
 		ret = 0;
 		dev->mei_host_buffer_is_empty = false;
-		if (cb->request_buffer.size >
-			(((dev->host_hw_state & H_CBD) >> 24) * sizeof(u32))
-				-sizeof(struct mei_msg_hdr)) {
-			mei_hdr.length =
-			    (((dev->host_hw_state & H_CBD) >> 24) *
-			    sizeof(u32)) - sizeof(struct mei_msg_hdr);
+		if (cb->request_buffer.size > mei_hbuf_max_data(dev)) {
+			mei_hdr.length = mei_hbuf_max_data(dev);
 			mei_hdr.msg_complete = 0;
 		} else {
 			mei_hdr.length = cb->request_buffer.size;
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index c70333228337..092330208869 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -714,13 +714,8 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 	if (rets && dev->mei_host_buffer_is_empty) {
 		rets = 0;
 		dev->mei_host_buffer_is_empty = false;
-		if (length > ((((dev->host_hw_state & H_CBD) >> 24) *
-			sizeof(u32)) - sizeof(struct mei_msg_hdr))) {
-
-			mei_hdr.length =
-				(((dev->host_hw_state & H_CBD) >> 24) *
-				sizeof(u32)) -
-				sizeof(struct mei_msg_hdr);
+		if (length >  mei_hbuf_max_data(dev)) {
+			mei_hdr.length = mei_hbuf_max_data(dev);
 			mei_hdr.msg_complete = 0;
 		} else {
 			mei_hdr.length = length;
@@ -982,7 +977,7 @@ static int __devinit mei_probe(struct pci_dev *pdev,
 		err = request_threaded_irq(pdev->irq,
 			NULL,
 			mei_interrupt_thread_handler,
-			0, mei_driver_name, dev);
+			IRQF_ONESHOT, mei_driver_name, dev);
 	else
 		err = request_threaded_irq(pdev->irq,
 			mei_interrupt_quick_handler,
@@ -992,7 +987,7 @@ static int __devinit mei_probe(struct pci_dev *pdev,
 	if (err) {
 		dev_err(&pdev->dev, "request_threaded_irq failure. irq = %d\n",
 		       pdev->irq);
-		goto unmap_memory;
+		goto disable_msi;
 	}
 	INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
 	if (mei_hw_init(dev)) {
@@ -1023,8 +1018,8 @@ release_irq:
 	mei_disable_interrupts(dev);
 	flush_scheduled_work();
 	free_irq(pdev->irq, dev);
+disable_msi:
 	pci_disable_msi(pdev);
-unmap_memory:
 	pci_iounmap(pdev, dev->mem_addr);
 free_device:
 	kfree(dev);
@@ -1101,6 +1096,8 @@ static void __devexit mei_remove(struct pci_dev *pdev)
 
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
+
+	misc_deregister(&mei_misc_device);
 }
 #ifdef CONFIG_PM
 static int mei_pci_suspend(struct device *device)
@@ -1145,7 +1142,7 @@ static int mei_pci_resume(struct device *device)
 		err = request_threaded_irq(pdev->irq,
 			NULL,
 			mei_interrupt_thread_handler,
-			0, mei_driver_name, dev);
+			IRQF_ONESHOT, mei_driver_name, dev);
 	else
 		err = request_threaded_irq(pdev->irq,
 			mei_interrupt_quick_handler,
@@ -1185,45 +1182,7 @@ static struct pci_driver mei_driver = {
 	.driver.pm = MEI_PM_OPS,
 };
 
-/**
- * mei_init_module - Driver Registration Routine
- *
- * mei_init_module is the first routine called when the driver is
- * loaded. All it does is to register with the PCI subsystem.
- *
- * returns 0 on success, <0 on failure.
- */
-static int __init mei_init_module(void)
-{
-	int ret;
-
-	pr_debug("loading.\n");
-	/* init pci module */
-	ret = pci_register_driver(&mei_driver);
-	if (ret < 0)
-		pr_err("error registering driver.\n");
-
-	return ret;
-}
-
-module_init(mei_init_module);
-
-/**
- * mei_exit_module - Driver Exit Cleanup Routine
- *
- * mei_exit_module is called just before the driver is removed
- * from memory.
- */
-static void __exit mei_exit_module(void)
-{
-	misc_deregister(&mei_misc_device);
-	pci_unregister_driver(&mei_driver);
-
-	pr_debug("unloaded successfully.\n");
-}
-
-module_exit(mei_exit_module);
-
+module_pci_driver(mei_driver);
 
 MODULE_AUTHOR("Intel Corporation");
 MODULE_DESCRIPTION("Intel(R) Management Engine Interface");
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 63d7ee97c5fb..d61c4ddfc80c 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -167,7 +167,10 @@ struct mei_io_list {
 	struct mei_cl_cb mei_cb;
 };
 
-/* MEI private device struct */
+/**
+ * struct mei_deive -  MEI private device struct
+ * @hbuf_depth - depth of host(write) buffer
+ */
 struct mei_device {
 	struct pci_dev *pdev;	/* pointer to pci device struct */
 	/*
@@ -205,6 +208,7 @@ struct mei_device {
 	 */
 	u32 host_hw_state;
 	u32 me_hw_state;
+	u8  hbuf_depth;
 	/*
 	 * waiting queue for receive message from FW
 	 */
@@ -237,15 +241,14 @@ struct mei_device {
 	bool mei_host_buffer_is_empty;
 
 	struct mei_cl wd_cl;
+	bool wd_interface_reg;
 	bool wd_pending;
 	bool wd_stopped;
 	bool wd_bypass;	/* if false, don't refresh watchdog ME client */
 	u16 wd_timeout;	/* seconds ((wd_data[1] << 8) + wd_data[0]) */
-	u16 wd_due_counter;
 	unsigned char wd_data[MEI_START_WD_DATA_SIZE];
 
 
-
 	struct file *iamthif_file_object;
 	struct mei_cl iamthif_cl;
 	struct mei_cl_cb *iamthif_current_cb;
@@ -259,8 +262,6 @@ struct mei_device {
 	bool iamthif_flow_control_pending;
 	bool iamthif_ioctl;
 	bool iamthif_canceled;
-
-	bool wd_interface_reg;
 };
 
 
@@ -361,7 +362,8 @@ int mei_find_me_client_index(const struct mei_device *dev, uuid_le cuuid);
  *
  * returns register value (u32)
  */
-static inline u32 mei_reg_read(struct mei_device *dev, unsigned long offset)
+static inline u32 mei_reg_read(const struct mei_device *dev,
+			       unsigned long offset)
 {
 	return ioread32(dev->mem_addr + offset);
 }
@@ -373,8 +375,8 @@ static inline u32 mei_reg_read(struct mei_device *dev, unsigned long offset)
  * @offset: offset from which to write the data
  * @value: register value to write (u32)
  */
-static inline void mei_reg_write(struct mei_device *dev,
-				unsigned long offset, u32 value)
+static inline void mei_reg_write(const struct mei_device *dev,
+				 unsigned long offset, u32 value)
 {
 	iowrite32(value, dev->mem_addr + offset);
 }
@@ -386,7 +388,7 @@ static inline void mei_reg_write(struct mei_device *dev,
  *
  * returns the byte read.
  */
-static inline u32 mei_hcsr_read(struct mei_device *dev)
+static inline u32 mei_hcsr_read(const struct mei_device *dev)
 {
 	return mei_reg_read(dev, H_CSR);
 }
@@ -398,7 +400,7 @@ static inline u32 mei_hcsr_read(struct mei_device *dev)
  *
  * returns ME_CSR_HA register value (u32)
  */
-static inline u32 mei_mecsr_read(struct mei_device *dev)
+static inline u32 mei_mecsr_read(const struct mei_device *dev)
 {
 	return mei_reg_read(dev, ME_CSR_HA);
 }
@@ -410,7 +412,7 @@ static inline u32 mei_mecsr_read(struct mei_device *dev)
  *
  * returns ME_CB_RW register value (u32)
  */
-static inline u32 mei_mecbrw_read(struct mei_device *dev)
+static inline u32 mei_mecbrw_read(const struct mei_device *dev)
 {
 	return mei_reg_read(dev, ME_CB_RW);
 }
diff --git a/drivers/misc/mei/wd.c b/drivers/misc/mei/wd.c
index 6be5605707b4..5133fd77b91c 100644
--- a/drivers/misc/mei/wd.c
+++ b/drivers/misc/mei/wd.c
@@ -53,11 +53,12 @@ static void mei_wd_set_start_timeout(struct mei_device *dev, u16 timeout)
 }
 
 /**
- * host_init_wd - mei initialization wd.
+ * mei_wd_host_init - connect to the watchdog client
  *
  * @dev: the device structure
  * returns -ENENT if wd client cannot be found
  *         -EIO if write has failed
+ *         0 on success
  */
 int mei_wd_host_init(struct mei_device *dev)
 {
@@ -137,7 +138,6 @@ int mei_wd_stop(struct mei_device *dev, bool preserve)
 		return 0;
 
 	dev->wd_timeout = 0;
-	dev->wd_due_counter = 0;
 	memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_PARAMS_SIZE);
 	dev->stop = true;
 
@@ -341,7 +341,7 @@ static const struct watchdog_ops wd_ops = {
 };
 static const struct watchdog_info wd_info = {
 		.identity = INTEL_AMT_WATCHDOG_ID,
-		.options = WDIOF_KEEPALIVEPING,
+		.options = WDIOF_KEEPALIVEPING | WDIOF_ALARMONLY,
 };
 
 static struct watchdog_device amt_wd_dev = {
@@ -357,8 +357,6 @@ void  mei_watchdog_register(struct mei_device *dev)
 {
 	dev_dbg(&dev->pdev->dev, "dev->wd_timeout =%d.\n", dev->wd_timeout);
 
-	dev->wd_due_counter = !!dev->wd_timeout;
-
 	if (watchdog_register_device(&amt_wd_dev)) {
 		dev_err(&dev->pdev->dev,
 			"wd: unable to register watchdog device.\n");