diff --git a/drivers/coresight/coresight-tmc.c b/drivers/coresight/coresight-tmc.c
index 042b735cbd05..cdea19e163c7 100644
--- a/drivers/coresight/coresight-tmc.c
+++ b/drivers/coresight/coresight-tmc.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2012-2017, 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
@@ -850,6 +850,14 @@ static int tmc_enable(struct tmc_drvdata *drvdata, enum tmc_mode mode)
 		return ret;
 
 	mutex_lock(&drvdata->usb_lock);
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+	if (drvdata->reading) {
+		ret = -EBUSY;
+		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		goto err0;
+	}
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
 	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
 		coresight_cti_map_trigout(drvdata->cti_flush, 1, 0);
 		coresight_cti_map_trigin(drvdata->cti_reset, 2, 0);
@@ -896,10 +904,6 @@ static int tmc_enable(struct tmc_drvdata *drvdata, enum tmc_mode mode)
 	}
 
 	spin_lock_irqsave(&drvdata->spinlock, flags);
-	if (drvdata->reading) {
-		ret = -EBUSY;
-		goto err1;
-	}
 
 	if (drvdata->config_type == TMC_CONFIG_TYPE_ETB) {
 		__tmc_etb_enable(drvdata);
@@ -929,11 +933,6 @@ static int tmc_enable(struct tmc_drvdata *drvdata, enum tmc_mode mode)
 
 	dev_info(drvdata->dev, "TMC enabled\n");
 	return 0;
-err1:
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
-	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
-		if (drvdata->out_mode == TMC_ETR_OUT_MODE_USB)
-			usb_qdss_close(drvdata->usbch);
 err0:
 	mutex_unlock(&drvdata->usb_lock);
 	clk_disable_unprepare(drvdata->clk);
@@ -1328,6 +1327,7 @@ static int tmc_read_prepare(struct tmc_drvdata *drvdata)
 	unsigned long flags;
 	enum tmc_mode mode;
 
+	mutex_lock(&drvdata->usb_lock);
 	spin_lock_irqsave(&drvdata->spinlock, flags);
 	if (!drvdata->sticky_enable) {
 		dev_err(drvdata->dev, "enable tmc once before reading\n");
@@ -1358,11 +1358,13 @@ static int tmc_read_prepare(struct tmc_drvdata *drvdata)
 out:
 	drvdata->reading = true;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	mutex_unlock(&drvdata->usb_lock);
 
 	dev_info(drvdata->dev, "TMC read start\n");
 	return 0;
 err:
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	mutex_unlock(&drvdata->usb_lock);
 	return ret;
 }
 
@@ -1544,8 +1546,12 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
 {
 	struct tmc_drvdata *drvdata = container_of(file->private_data,
 						   struct tmc_drvdata, miscdev);
-	char *bufp = drvdata->buf + *ppos;
-	char *end = (char *)(drvdata->vaddr + drvdata->size);
+	char *bufp, *end;
+
+	mutex_lock(&drvdata->usb_lock);
+
+	bufp  = drvdata->buf + *ppos;
+	end = (char *)(drvdata->vaddr + drvdata->size);
 
 	if (*ppos + len > drvdata->size)
 		len = drvdata->size - *ppos;
@@ -1572,6 +1578,7 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
 
 	if (copy_to_user(data, bufp, len)) {
 		dev_dbg(drvdata->dev, "%s: copy_to_user failed\n", __func__);
+		mutex_unlock(&drvdata->usb_lock);
 		return -EFAULT;
 	}
 
@@ -1579,6 +1586,8 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
 out:
 	dev_dbg(drvdata->dev, "%s: %zu bytes copied, %d bytes left\n",
 		__func__, len, (int) (drvdata->size - *ppos));
+
+	mutex_unlock(&drvdata->usb_lock);
 	return len;
 }