diff --git a/drivers/mailbox/tegra-hsp.c b/drivers/mailbox/tegra-hsp.c
index 0cde356c11ab..d070c8e38375 100644
--- a/drivers/mailbox/tegra-hsp.c
+++ b/drivers/mailbox/tegra-hsp.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2016-2018, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -11,6 +11,7 @@
  * more details.
  */
 
+#include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/mailbox_controller.h>
@@ -21,6 +22,17 @@
 
 #include <dt-bindings/mailbox/tegra186-hsp.h>
 
+#include "mailbox.h"
+
+#define HSP_INT_IE(x)		(0x100 + ((x) * 4))
+#define HSP_INT_IV		0x300
+#define HSP_INT_IR		0x304
+
+#define HSP_INT_EMPTY_SHIFT	0
+#define HSP_INT_EMPTY_MASK	0xff
+#define HSP_INT_FULL_SHIFT	8
+#define HSP_INT_FULL_MASK	0xff
+
 #define HSP_INT_DIMENSIONING	0x380
 #define HSP_nSM_SHIFT		0
 #define HSP_nSS_SHIFT		4
@@ -34,6 +46,11 @@
 #define HSP_DB_RAW	0x8
 #define HSP_DB_PENDING	0xc
 
+#define HSP_SM_SHRD_MBOX	0x0
+#define HSP_SM_SHRD_MBOX_FULL	BIT(31)
+#define HSP_SM_SHRD_MBOX_FULL_INT_IE	0x04
+#define HSP_SM_SHRD_MBOX_EMPTY_INT_IE	0x08
+
 #define HSP_DB_CCPLEX		1
 #define HSP_DB_BPMP		3
 #define HSP_DB_MAX		7
@@ -55,6 +72,12 @@ struct tegra_hsp_doorbell {
 	unsigned int index;
 };
 
+struct tegra_hsp_mailbox {
+	struct tegra_hsp_channel channel;
+	unsigned int index;
+	bool sending;
+};
+
 struct tegra_hsp_db_map {
 	const char *name;
 	unsigned int master;
@@ -66,10 +89,13 @@ struct tegra_hsp_soc {
 };
 
 struct tegra_hsp {
+	struct device *dev;
 	const struct tegra_hsp_soc *soc;
-	struct mbox_controller mbox;
+	struct mbox_controller mbox_db;
+	struct mbox_controller mbox_sm;
 	void __iomem *regs;
-	unsigned int irq;
+	unsigned int doorbell_irq;
+	unsigned int *shared_irqs;
 	unsigned int num_sm;
 	unsigned int num_as;
 	unsigned int num_ss;
@@ -78,14 +104,9 @@ struct tegra_hsp {
 	spinlock_t lock;
 
 	struct list_head doorbells;
+	struct tegra_hsp_mailbox *mailboxes;
 };
 
-static inline struct tegra_hsp *
-to_tegra_hsp(struct mbox_controller *mbox)
-{
-	return container_of(mbox, struct tegra_hsp, mbox);
-}
-
 static inline u32 tegra_hsp_readl(struct tegra_hsp *hsp, unsigned int offset)
 {
 	return readl(hsp->regs + offset);
@@ -158,7 +179,7 @@ static irqreturn_t tegra_hsp_doorbell_irq(int irq, void *data)
 
 	spin_lock(&hsp->lock);
 
-	for_each_set_bit(master, &value, hsp->mbox.num_chans) {
+	for_each_set_bit(master, &value, hsp->mbox_db.num_chans) {
 		struct tegra_hsp_doorbell *db;
 
 		db = __tegra_hsp_doorbell_get(hsp, master);
@@ -182,6 +203,84 @@ static irqreturn_t tegra_hsp_doorbell_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t tegra_hsp_shared_full_irq(int irq, void *data)
+{
+	struct tegra_hsp *hsp = data;
+	unsigned long bit, mask;
+	u32 status, value;
+	void *msg;
+
+	status = tegra_hsp_readl(hsp, HSP_INT_IR);
+
+	/* only interested in FULL interrupts */
+	mask = (status >> HSP_INT_FULL_SHIFT) & HSP_INT_FULL_MASK;
+
+	if (!mask)
+		return IRQ_NONE;
+
+	for_each_set_bit(bit, &mask, hsp->num_sm) {
+		struct tegra_hsp_mailbox *mb = &hsp->mailboxes[bit];
+
+		if (!mb->sending) {
+			value = tegra_hsp_channel_readl(&mb->channel,
+							HSP_SM_SHRD_MBOX);
+			value &= ~HSP_SM_SHRD_MBOX_FULL;
+			msg = (void *)(unsigned long)value;
+			mbox_chan_received_data(mb->channel.chan, msg);
+
+			/*
+			 * Need to clear all bits here since some producers,
+			 * such as TCU, depend on fields in the register
+			 * getting cleared by the consumer.
+			 *
+			 * The mailbox API doesn't give the consumers a way
+			 * of doing that explicitly, so we have to make sure
+			 * we cover all possible cases.
+			 */
+			tegra_hsp_channel_writel(&mb->channel, 0x0,
+						 HSP_SM_SHRD_MBOX);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t tegra_hsp_shared_empty_irq(int irq, void *data)
+{
+	struct tegra_hsp *hsp = data;
+	unsigned long bit, mask;
+	u32 status, value;
+
+	status = tegra_hsp_readl(hsp, HSP_INT_IR);
+
+	/* only interested in EMPTY interrupts */
+	mask = (status >> HSP_INT_EMPTY_SHIFT) & HSP_INT_EMPTY_MASK;
+
+	if (!mask)
+		return IRQ_NONE;
+
+	for_each_set_bit(bit, &mask, hsp->num_sm) {
+		struct tegra_hsp_mailbox *mb = &hsp->mailboxes[bit];
+
+		if (mb->sending) {
+			/*
+			 * Disable EMPTY interrupts until data is sent
+			 * with the next message. These interrupts are
+			 * level-triggered, so if we kept them enabled
+			 * they would constantly trigger until we next
+			 * write data into the message.
+			 */
+			value = tegra_hsp_readl(hsp, HSP_INT_IE(1));
+			value &= ~BIT(HSP_INT_EMPTY_SHIFT + mb->index);
+			tegra_hsp_writel(hsp, value, HSP_INT_IE(1));
+
+			mbox_chan_txdone(mb->channel.chan, 0);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
 static struct tegra_hsp_channel *
 tegra_hsp_doorbell_create(struct tegra_hsp *hsp, const char *name,
 			  unsigned int master, unsigned int index)
@@ -194,7 +293,7 @@ tegra_hsp_doorbell_create(struct tegra_hsp *hsp, const char *name,
 	if (!db)
 		return ERR_PTR(-ENOMEM);
 
-	offset = (1 + (hsp->num_sm / 2) + hsp->num_ss + hsp->num_as) << 16;
+	offset = (1 + (hsp->num_sm / 2) + hsp->num_ss + hsp->num_as) * SZ_64K;
 	offset += index * 0x100;
 
 	db->channel.regs = hsp->regs + offset;
@@ -235,8 +334,8 @@ static int tegra_hsp_doorbell_startup(struct mbox_chan *chan)
 	unsigned long flags;
 	u32 value;
 
-	if (db->master >= hsp->mbox.num_chans) {
-		dev_err(hsp->mbox.dev,
+	if (db->master >= chan->mbox->num_chans) {
+		dev_err(chan->mbox->dev,
 			"invalid master ID %u for HSP channel\n",
 			db->master);
 		return -EINVAL;
@@ -281,46 +380,147 @@ static void tegra_hsp_doorbell_shutdown(struct mbox_chan *chan)
 	spin_unlock_irqrestore(&hsp->lock, flags);
 }
 
-static const struct mbox_chan_ops tegra_hsp_doorbell_ops = {
+static const struct mbox_chan_ops tegra_hsp_db_ops = {
 	.send_data = tegra_hsp_doorbell_send_data,
 	.startup = tegra_hsp_doorbell_startup,
 	.shutdown = tegra_hsp_doorbell_shutdown,
 };
 
-static struct mbox_chan *of_tegra_hsp_xlate(struct mbox_controller *mbox,
+static int tegra_hsp_mailbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct tegra_hsp_mailbox *mb = chan->con_priv;
+	struct tegra_hsp *hsp = mb->channel.hsp;
+	u32 value;
+
+	mb->sending = true;
+
+	/* copy data and mark mailbox full */
+	value = (u32)(unsigned long)data;
+	value |= HSP_SM_SHRD_MBOX_FULL;
+
+	tegra_hsp_channel_writel(&mb->channel, value, HSP_SM_SHRD_MBOX);
+
+	if (!irqs_disabled()) {
+		/* enable EMPTY interrupt for the shared mailbox */
+		value = tegra_hsp_readl(hsp, HSP_INT_IE(1));
+		value |= BIT(HSP_INT_EMPTY_SHIFT + mb->index);
+		tegra_hsp_writel(hsp, value, HSP_INT_IE(1));
+	}
+
+	return 0;
+}
+
+static int tegra_hsp_mailbox_flush(struct mbox_chan *chan,
+				   unsigned long timeout)
+{
+	struct tegra_hsp_mailbox *mb = chan->con_priv;
+	struct tegra_hsp_channel *ch = &mb->channel;
+	u32 value;
+
+	timeout = jiffies + msecs_to_jiffies(timeout);
+
+	while (time_before(jiffies, timeout)) {
+		value = tegra_hsp_channel_readl(ch, HSP_SM_SHRD_MBOX);
+		if ((value & HSP_SM_SHRD_MBOX_FULL) == 0) {
+			mbox_chan_txdone(chan, 0);
+			return 0;
+		}
+
+		udelay(1);
+	}
+
+	return -ETIME;
+}
+
+static int tegra_hsp_mailbox_startup(struct mbox_chan *chan)
+{
+	struct tegra_hsp_mailbox *mb = chan->con_priv;
+	struct tegra_hsp_channel *ch = &mb->channel;
+	struct tegra_hsp *hsp = mb->channel.hsp;
+	u32 value;
+
+	chan->txdone_method = TXDONE_BY_IRQ;
+
+	/*
+	 * Shared mailboxes start out as consumers by default. FULL interrupts
+	 * are coalesced at shared interrupt 0, while EMPTY interrupts will be
+	 * coalesced at shared interrupt 1.
+	 *
+	 * Keep EMPTY interrupts disabled at startup and only enable them when
+	 * the mailbox is actually full. This is required because the FULL and
+	 * EMPTY interrupts are level-triggered, so keeping EMPTY interrupts
+	 * enabled all the time would cause an interrupt storm while mailboxes
+	 * are idle.
+	 */
+
+	value = tegra_hsp_readl(hsp, HSP_INT_IE(0));
+	value |= BIT(HSP_INT_FULL_SHIFT + mb->index);
+	tegra_hsp_writel(hsp, value, HSP_INT_IE(0));
+
+	value = tegra_hsp_readl(hsp, HSP_INT_IE(1));
+	value &= ~BIT(HSP_INT_EMPTY_SHIFT + mb->index);
+	tegra_hsp_writel(hsp, value, HSP_INT_IE(1));
+
+	tegra_hsp_channel_writel(ch, 0x1, HSP_SM_SHRD_MBOX_FULL_INT_IE);
+	tegra_hsp_channel_writel(ch, 0x1, HSP_SM_SHRD_MBOX_EMPTY_INT_IE);
+
+	return 0;
+}
+
+static void tegra_hsp_mailbox_shutdown(struct mbox_chan *chan)
+{
+	struct tegra_hsp_mailbox *mb = chan->con_priv;
+	struct tegra_hsp_channel *ch = &mb->channel;
+	struct tegra_hsp *hsp = mb->channel.hsp;
+	u32 value;
+
+	tegra_hsp_channel_writel(ch, 0x0, HSP_SM_SHRD_MBOX_EMPTY_INT_IE);
+	tegra_hsp_channel_writel(ch, 0x0, HSP_SM_SHRD_MBOX_FULL_INT_IE);
+
+	value = tegra_hsp_readl(hsp, HSP_INT_IE(1));
+	value &= ~BIT(HSP_INT_EMPTY_SHIFT + mb->index);
+	tegra_hsp_writel(hsp, value, HSP_INT_IE(1));
+
+	value = tegra_hsp_readl(hsp, HSP_INT_IE(0));
+	value &= ~BIT(HSP_INT_FULL_SHIFT + mb->index);
+	tegra_hsp_writel(hsp, value, HSP_INT_IE(0));
+}
+
+static const struct mbox_chan_ops tegra_hsp_sm_ops = {
+	.send_data = tegra_hsp_mailbox_send_data,
+	.flush = tegra_hsp_mailbox_flush,
+	.startup = tegra_hsp_mailbox_startup,
+	.shutdown = tegra_hsp_mailbox_shutdown,
+};
+
+static struct mbox_chan *tegra_hsp_db_xlate(struct mbox_controller *mbox,
 					    const struct of_phandle_args *args)
 {
+	struct tegra_hsp *hsp = container_of(mbox, struct tegra_hsp, mbox_db);
+	unsigned int type = args->args[0], master = args->args[1];
 	struct tegra_hsp_channel *channel = ERR_PTR(-ENODEV);
-	struct tegra_hsp *hsp = to_tegra_hsp(mbox);
-	unsigned int type = args->args[0];
-	unsigned int master = args->args[1];
 	struct tegra_hsp_doorbell *db;
 	struct mbox_chan *chan;
 	unsigned long flags;
 	unsigned int i;
 
-	switch (type) {
-	case TEGRA_HSP_MBOX_TYPE_DB:
-		db = tegra_hsp_doorbell_get(hsp, master);
-		if (db)
-			channel = &db->channel;
+	if (type != TEGRA_HSP_MBOX_TYPE_DB || !hsp->doorbell_irq)
+		return ERR_PTR(-ENODEV);
 
-		break;
-
-	default:
-		break;
-	}
+	db = tegra_hsp_doorbell_get(hsp, master);
+	if (db)
+		channel = &db->channel;
 
 	if (IS_ERR(channel))
 		return ERR_CAST(channel);
 
 	spin_lock_irqsave(&hsp->lock, flags);
 
-	for (i = 0; i < hsp->mbox.num_chans; i++) {
-		chan = &hsp->mbox.chans[i];
+	for (i = 0; i < mbox->num_chans; i++) {
+		chan = &mbox->chans[i];
 		if (!chan->con_priv) {
-			chan->con_priv = channel;
 			channel->chan = chan;
+			chan->con_priv = db;
 			break;
 		}
 
@@ -332,6 +532,19 @@ static struct mbox_chan *of_tegra_hsp_xlate(struct mbox_controller *mbox,
 	return chan ?: ERR_PTR(-EBUSY);
 }
 
+static struct mbox_chan *tegra_hsp_sm_xlate(struct mbox_controller *mbox,
+					    const struct of_phandle_args *args)
+{
+	struct tegra_hsp *hsp = container_of(mbox, struct tegra_hsp, mbox_sm);
+	unsigned int type = args->args[0], index = args->args[1];
+
+	if (type != TEGRA_HSP_MBOX_TYPE_SM || !hsp->shared_irqs ||
+	    index >= hsp->num_sm)
+		return ERR_PTR(-ENODEV);
+
+	return hsp->mailboxes[index].channel.chan;
+}
+
 static void tegra_hsp_remove_doorbells(struct tegra_hsp *hsp)
 {
 	struct tegra_hsp_doorbell *db, *tmp;
@@ -364,10 +577,72 @@ static int tegra_hsp_add_doorbells(struct tegra_hsp *hsp)
 	return 0;
 }
 
+static int tegra_hsp_add_mailboxes(struct tegra_hsp *hsp, struct device *dev)
+{
+	int i;
+
+	hsp->mailboxes = devm_kcalloc(dev, hsp->num_sm, sizeof(*hsp->mailboxes),
+				      GFP_KERNEL);
+	if (!hsp->mailboxes)
+		return -ENOMEM;
+
+	for (i = 0; i < hsp->num_sm; i++) {
+		struct tegra_hsp_mailbox *mb = &hsp->mailboxes[i];
+
+		mb->index = i;
+		mb->sending = false;
+
+		mb->channel.hsp = hsp;
+		mb->channel.regs = hsp->regs + SZ_64K + i * SZ_32K;
+		mb->channel.chan = &hsp->mbox_sm.chans[i];
+		mb->channel.chan->con_priv = mb;
+	}
+
+	return 0;
+}
+
+static int tegra_hsp_request_shared_irqs(struct tegra_hsp *hsp)
+{
+	int err;
+
+	if (hsp->shared_irqs[0] > 0) {
+		err = devm_request_irq(hsp->dev, hsp->shared_irqs[0],
+				       tegra_hsp_shared_full_irq, 0,
+				       dev_name(hsp->dev), hsp);
+		if (err < 0) {
+			dev_err(hsp->dev,
+				"failed to request full interrupt: %d\n",
+				err);
+			return err;
+		}
+
+		dev_dbg(hsp->dev, "full interrupt requested: %u\n",
+			hsp->shared_irqs[0]);
+	}
+
+	if (hsp->shared_irqs[1] > 0) {
+		err = devm_request_irq(hsp->dev, hsp->shared_irqs[1],
+				       tegra_hsp_shared_empty_irq, 0,
+				       dev_name(hsp->dev), hsp);
+		if (err < 0) {
+			dev_err(hsp->dev,
+				"failed to request empty interrupt: %d\n",
+				err);
+			return err;
+		}
+
+		dev_dbg(hsp->dev, "empty interrupt requested: %u\n",
+			hsp->shared_irqs[1]);
+	}
+
+	return 0;
+}
+
 static int tegra_hsp_probe(struct platform_device *pdev)
 {
 	struct tegra_hsp *hsp;
 	struct resource *res;
+	unsigned int i;
 	u32 value;
 	int err;
 
@@ -375,6 +650,7 @@ static int tegra_hsp_probe(struct platform_device *pdev)
 	if (!hsp)
 		return -ENOMEM;
 
+	hsp->dev = &pdev->dev;
 	hsp->soc = of_device_get_match_data(&pdev->dev);
 	INIT_LIST_HEAD(&hsp->doorbells);
 	spin_lock_init(&hsp->lock);
@@ -392,58 +668,136 @@ static int tegra_hsp_probe(struct platform_device *pdev)
 	hsp->num_si = (value >> HSP_nSI_SHIFT) & HSP_nINT_MASK;
 
 	err = platform_get_irq_byname(pdev, "doorbell");
-	if (err < 0) {
-		dev_err(&pdev->dev, "failed to get doorbell IRQ: %d\n", err);
-		return err;
+	if (err >= 0)
+		hsp->doorbell_irq = err;
+
+	if (hsp->num_si > 0) {
+		unsigned int count = 0;
+
+		hsp->shared_irqs = devm_kcalloc(&pdev->dev, hsp->num_si,
+						sizeof(*hsp->shared_irqs),
+						GFP_KERNEL);
+		if (!hsp->shared_irqs)
+			return -ENOMEM;
+
+		for (i = 0; i < hsp->num_si; i++) {
+			char *name;
+
+			name = kasprintf(GFP_KERNEL, "shared%u", i);
+			if (!name)
+				return -ENOMEM;
+
+			err = platform_get_irq_byname(pdev, name);
+			if (err >= 0) {
+				hsp->shared_irqs[i] = err;
+				count++;
+			}
+
+			kfree(name);
+		}
+
+		if (count == 0) {
+			devm_kfree(&pdev->dev, hsp->shared_irqs);
+			hsp->shared_irqs = NULL;
+		}
 	}
 
-	hsp->irq = err;
+	/* setup the doorbell controller */
+	hsp->mbox_db.of_xlate = tegra_hsp_db_xlate;
+	hsp->mbox_db.num_chans = 32;
+	hsp->mbox_db.dev = &pdev->dev;
+	hsp->mbox_db.ops = &tegra_hsp_db_ops;
 
-	hsp->mbox.of_xlate = of_tegra_hsp_xlate;
-	hsp->mbox.num_chans = 32;
-	hsp->mbox.dev = &pdev->dev;
-	hsp->mbox.txdone_irq = false;
-	hsp->mbox.txdone_poll = false;
-	hsp->mbox.ops = &tegra_hsp_doorbell_ops;
+	hsp->mbox_db.chans = devm_kcalloc(&pdev->dev, hsp->mbox_db.num_chans,
+					  sizeof(*hsp->mbox_db.chans),
+					  GFP_KERNEL);
+	if (!hsp->mbox_db.chans)
+		return -ENOMEM;
 
-	hsp->mbox.chans = devm_kcalloc(&pdev->dev, hsp->mbox.num_chans,
-					sizeof(*hsp->mbox.chans),
-					GFP_KERNEL);
-	if (!hsp->mbox.chans)
+	if (hsp->doorbell_irq) {
+		err = tegra_hsp_add_doorbells(hsp);
+		if (err < 0) {
+			dev_err(&pdev->dev, "failed to add doorbells: %d\n",
+			        err);
+			return err;
+		}
+	}
+
+	err = mbox_controller_register(&hsp->mbox_db);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to register doorbell mailbox: %d\n", err);
+		goto remove_doorbells;
+	}
+
+	/* setup the shared mailbox controller */
+	hsp->mbox_sm.of_xlate = tegra_hsp_sm_xlate;
+	hsp->mbox_sm.num_chans = hsp->num_sm;
+	hsp->mbox_sm.dev = &pdev->dev;
+	hsp->mbox_sm.ops = &tegra_hsp_sm_ops;
+
+	hsp->mbox_sm.chans = devm_kcalloc(&pdev->dev, hsp->mbox_sm.num_chans,
+					  sizeof(*hsp->mbox_sm.chans),
+					  GFP_KERNEL);
+	if (!hsp->mbox_sm.chans)
 		return -ENOMEM;
 
-	err = tegra_hsp_add_doorbells(hsp);
+	if (hsp->shared_irqs) {
+		err = tegra_hsp_add_mailboxes(hsp, &pdev->dev);
+		if (err < 0) {
+			dev_err(&pdev->dev, "failed to add mailboxes: %d\n",
+			        err);
+			goto unregister_mbox_db;
+		}
+	}
+
+	err = mbox_controller_register(&hsp->mbox_sm);
 	if (err < 0) {
-		dev_err(&pdev->dev, "failed to add doorbells: %d\n", err);
-		return err;
+		dev_err(&pdev->dev, "failed to register shared mailbox: %d\n", err);
+		goto unregister_mbox_db;
 	}
 
 	platform_set_drvdata(pdev, hsp);
 
-	err = mbox_controller_register(&hsp->mbox);
-	if (err) {
-		dev_err(&pdev->dev, "failed to register mailbox: %d\n", err);
-		tegra_hsp_remove_doorbells(hsp);
-		return err;
+	if (hsp->doorbell_irq) {
+		err = devm_request_irq(&pdev->dev, hsp->doorbell_irq,
+				       tegra_hsp_doorbell_irq, IRQF_NO_SUSPEND,
+				       dev_name(&pdev->dev), hsp);
+		if (err < 0) {
+			dev_err(&pdev->dev,
+			        "failed to request doorbell IRQ#%u: %d\n",
+				hsp->doorbell_irq, err);
+			goto unregister_mbox_sm;
+		}
 	}
 
-	err = devm_request_irq(&pdev->dev, hsp->irq, tegra_hsp_doorbell_irq,
-			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), hsp);
-	if (err < 0) {
-		dev_err(&pdev->dev, "failed to request IRQ#%u: %d\n",
-			hsp->irq, err);
-		return err;
+	if (hsp->shared_irqs) {
+		err = tegra_hsp_request_shared_irqs(hsp);
+		if (err < 0)
+			goto unregister_mbox_sm;
 	}
 
 	return 0;
+
+unregister_mbox_sm:
+	mbox_controller_unregister(&hsp->mbox_sm);
+unregister_mbox_db:
+	mbox_controller_unregister(&hsp->mbox_db);
+remove_doorbells:
+	if (hsp->doorbell_irq)
+		tegra_hsp_remove_doorbells(hsp);
+
+	return err;
 }
 
 static int tegra_hsp_remove(struct platform_device *pdev)
 {
 	struct tegra_hsp *hsp = platform_get_drvdata(pdev);
 
-	mbox_controller_unregister(&hsp->mbox);
-	tegra_hsp_remove_doorbells(hsp);
+	mbox_controller_unregister(&hsp->mbox_sm);
+	mbox_controller_unregister(&hsp->mbox_db);
+
+	if (hsp->doorbell_irq)
+		tegra_hsp_remove_doorbells(hsp);
 
 	return 0;
 }
