diff --git a/drivers/char/diag/diagchar_core.c b/drivers/char/diag/diagchar_core.c
index 8629e3e28886..9b953e6b7b5c 100644
--- a/drivers/char/diag/diagchar_core.c
+++ b/drivers/char/diag/diagchar_core.c
@@ -4290,7 +4290,7 @@ static void diag_debug_init(void)
 	 * to be logged to IPC
 	 */
 	diag_debug_mask = DIAG_DEBUG_PERIPHERALS | DIAG_DEBUG_DCI |
-				DIAG_DEBUG_USERSPACE | DIAG_DEBUG_BRIDGE;
+		DIAG_DEBUG_MHI | DIAG_DEBUG_USERSPACE | DIAG_DEBUG_BRIDGE;
 }
 #else
 static void diag_debug_init(void)
diff --git a/drivers/char/diag/diagfwd_bridge.c b/drivers/char/diag/diagfwd_bridge.c
index 754a53a4e229..f8f4425df428 100644
--- a/drivers/char/diag/diagfwd_bridge.c
+++ b/drivers/char/diag/diagfwd_bridge.c
@@ -87,7 +87,7 @@ static int diagfwd_bridge_mux_write_done(unsigned char *buf, int len,
 		return -EINVAL;
 	ch = &bridge_info[buf_ctx];
 	if (ch->dev_ops && ch->dev_ops->fwd_complete) {
-		DIAG_LOG(DIAG_DEBUG_MHI,
+		DIAG_LOG(DIAG_DEBUG_BRIDGE,
 		"Write done completion received for buf %pK len:%d\n",
 			buf, len);
 		ch->dev_ops->fwd_complete(ch->ctxt, buf, len, 0);
diff --git a/drivers/char/diag/diagfwd_mhi.c b/drivers/char/diag/diagfwd_mhi.c
index 404f265beb2a..a5c3832f46f3 100644
--- a/drivers/char/diag/diagfwd_mhi.c
+++ b/drivers/char/diag/diagfwd_mhi.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2014-2019, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2014-2020, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -149,9 +149,12 @@ static void mhi_buf_tbl_remove(struct diag_mhi_info *mhi_info, int type,
 		list_del(&item->link);
 		if (type == TYPE_MHI_READ_CH) {
 			DIAG_LOG(DIAG_DEBUG_MHI,
-			"Callback received on buffer:%pK from mhi\n", buf);
+			"Freeing read channel buffer: %pK\n", buf);
 			diagmem_free(driver, item->buf, mhi_info->mempool);
 		}
+		DIAG_LOG(DIAG_DEBUG_MHI,
+		"Removing %s channel item entry from table: %pK\n",
+			mhi_info->name, buf);
 		kfree(item);
 		found = 1;
 	}
@@ -189,7 +192,7 @@ static void mhi_buf_tbl_clear(struct diag_mhi_info *mhi_info)
 				&mhi_info->read_done_list, link) {
 				if (tp->buf == buf) {
 					DIAG_LOG(DIAG_DEBUG_MHI,
-						"buffer:%pK removed from table for ch:%s\n",
+						"Read buffer:%pK removed from table for ch:%s\n",
 						buf, mhi_info->name);
 					list_del(&tp->link);
 					kfree(tp);
@@ -211,6 +214,9 @@ static void mhi_buf_tbl_clear(struct diag_mhi_info *mhi_info)
 			item = list_entry(start, struct diag_mhi_buf_tbl_t,
 					  link);
 			list_del(&item->link);
+			DIAG_LOG(DIAG_DEBUG_MHI,
+			"Write buffer %pK removed from table for ch: %s\n",
+			buf, mhi_info->name);
 			diag_remote_dev_write_done(mhi_info->dev_id, item->buf,
 						   item->len, mhi_info->id);
 			kfree(item);
@@ -237,6 +243,9 @@ static int __mhi_close(struct diag_mhi_info *mhi_info, int close_flag)
 
 	if (close_flag == CLOSE_CHANNELS) {
 		mutex_lock(&mhi_info->ch_mutex);
+		DIAG_LOG(DIAG_DEBUG_MHI,
+			"diag: %s mhi channel closed, calling mhi unprepare\n",
+			mhi_info->name);
 		mhi_unprepare_from_transfer(mhi_info->mhi_dev);
 		mutex_unlock(&mhi_info->ch_mutex);
 	}
@@ -252,8 +261,11 @@ static int mhi_close(int id)
 		return -EINVAL;
 	}
 
-	if (!diag_mhi[id].enabled)
+	if (!diag_mhi[id].enabled) {
+		pr_err("diag: %s: mhi channel with index: %d is not enabled\n",
+			__func__, id);
 		return -ENODEV;
+	}
 	/*
 	 * This function is called whenever the channel needs to be closed
 	 * explicitly by Diag. Close both the read and write channels (denoted
@@ -286,9 +298,16 @@ static int __mhi_open(struct diag_mhi_info *mhi_info, int open_flag)
 		return -ENODEV;
 	if (open_flag == OPEN_CHANNELS) {
 		if ((atomic_read(&(mhi_info->read_ch.opened))) &&
-			(atomic_read(&(mhi_info->write_ch.opened))))
+			(atomic_read(&(mhi_info->write_ch.opened)))) {
+			DIAG_LOG(DIAG_DEBUG_MHI,
+			"Read and write channel already open: %s\n",
+			mhi_info->name);
 			return 0;
+		}
 		mutex_lock(&mhi_info->ch_mutex);
+		DIAG_LOG(DIAG_DEBUG_MHI,
+			"Prepare mhi for transfer on port: %s\n",
+			mhi_info->name);
 		err = mhi_prepare_for_transfer(mhi_info->mhi_dev);
 		mutex_unlock(&mhi_info->ch_mutex);
 		if (err) {
@@ -298,9 +317,9 @@ static int __mhi_open(struct diag_mhi_info *mhi_info, int open_flag)
 		}
 		atomic_set(&mhi_info->read_ch.opened, 1);
 		atomic_set(&mhi_info->write_ch.opened, 1);
-		DIAG_LOG(DIAG_DEBUG_BRIDGE,
-			 "opened mhi read/write channel, port: %d\n",
-			mhi_info->id);
+		DIAG_LOG(DIAG_DEBUG_MHI,
+			"opened mhi read/write channel, port: %s\n",
+			mhi_info->name);
 	} else if (open_flag == CHANNELS_OPENED) {
 		if (!atomic_read(&(mhi_info->read_ch.opened)) ||
 		    !atomic_read(&(mhi_info->write_ch.opened))) {
@@ -387,7 +406,7 @@ static void mhi_read_done_work_fn(struct work_struct *work)
 		spin_unlock_irqrestore(&mhi_info->read_ch.lock, flags);
 		if (!buf)
 			break;
-		DIAG_LOG(DIAG_DEBUG_BRIDGE,
+		DIAG_LOG(DIAG_DEBUG_MHI,
 			"read from mhi port %d buf %pK len:%d\n",
 			mhi_info->id, buf, len);
 		/*
@@ -453,7 +472,7 @@ static void mhi_read_work_fn(struct work_struct *work)
 			goto fail;
 		}
 
-		DIAG_LOG(DIAG_DEBUG_BRIDGE,
+		DIAG_LOG(DIAG_DEBUG_MHI,
 			 "queueing a read buf %pK, ch: %s\n",
 			 buf, mhi_info->name);
 
@@ -525,6 +544,8 @@ static int mhi_write(int id, unsigned char *buf, int len, int ctxt)
 		spin_unlock_irqrestore(&ch->lock, flags);
 		goto fail;
 	}
+	DIAG_LOG(DIAG_DEBUG_MHI, "diag: queueing a write buf %pK, ch: %s\n",
+		 buf, diag_mhi[id].name);
 
 	err = mhi_queue_transfer(diag_mhi[id].mhi_dev, DMA_TO_DEVICE, buf,
 				len, mhi_flags);
@@ -602,7 +623,7 @@ static void diag_mhi_read_cb(struct mhi_device *mhi_dev,
 		spin_lock_irqsave(&mhi_info->read_ch.lock, flags);
 		tp = kmalloc(sizeof(*tp), GFP_ATOMIC);
 		if (!tp) {
-			DIAG_LOG(DIAG_DEBUG_BRIDGE,
+			DIAG_LOG(DIAG_DEBUG_MHI,
 			"no mem for list\n");
 			spin_unlock_irqrestore(&mhi_info->read_ch.lock, flags);
 			return;
@@ -611,7 +632,7 @@ static void diag_mhi_read_cb(struct mhi_device *mhi_dev,
 				&mhi_info->read_ch.buf_tbl, link) {
 			if (item->buf == buf) {
 				DIAG_LOG(DIAG_DEBUG_MHI,
-				"Callback received on buffer:%pK from mhi\n",
+				"Read callback received on buffer:%pK from mhi\n",
 					buf);
 				tp->buf = buf;
 				tp->len = result->bytes_xferd;
@@ -651,6 +672,9 @@ static void diag_mhi_write_cb(struct mhi_device *mhi_dev,
 					__func__);
 		return;
 	}
+	DIAG_LOG(DIAG_DEBUG_MHI,
+		"Write callback received on buffer:%pK from mhi\n",
+		buf);
 	mhi_buf_tbl_remove(mhi_info, TYPE_MHI_WRITE_CH, buf,
 				   result->bytes_xferd);
 	diag_remote_dev_write_done(mhi_info->dev_id, buf,
@@ -670,6 +694,11 @@ static void diag_mhi_remove(struct mhi_device *mhi_dev)
 		return;
 	if (!mhi_info->enabled)
 		return;
+
+	DIAG_LOG(DIAG_DEBUG_MHI,
+		"Remove called on mhi channel: %s\n",
+		mhi_info->name);
+
 	__mhi_close(mhi_info, CHANNELS_CLOSED);
 	spin_lock_irqsave(&mhi_info->lock, flags);
 	mhi_info->enabled = 0;
@@ -684,11 +713,11 @@ static int diag_mhi_probe(struct mhi_device *mhi_dev,
 	unsigned long flags;
 	struct diag_mhi_info *mhi_info = &diag_mhi[index];
 
-	DIAG_LOG(DIAG_DEBUG_BRIDGE,
+	DIAG_LOG(DIAG_DEBUG_MHI,
 		"received probe for %d\n",
 		index);
 	diag_mhi[index].mhi_dev = mhi_dev;
-	DIAG_LOG(DIAG_DEBUG_BRIDGE,
+	DIAG_LOG(DIAG_DEBUG_MHI,
 		"diag: mhi device is ready to open\n");
 	spin_lock_irqsave(&mhi_info->lock, flags);
 	mhi_info->enabled = 1;
@@ -758,7 +787,7 @@ int diag_mhi_init(void)
 			       i, err);
 			goto fail;
 		}
-		DIAG_LOG(DIAG_DEBUG_BRIDGE, "mhi port %d is initailzed\n", i);
+		DIAG_LOG(DIAG_DEBUG_MHI, "mhi port %d is initailzed\n", i);
 	}
 
 	return 0;