Re: [PATCH 4/9] mailbox: tegra-hsp: Add support for shared mailboxes

[Pekka Pessi]

Hi Thierry,

There is typically one entity (aux cpu or a VM running on CCPLEX) owning 
the "empty" or producer side of mailbox (iow, waking up on empty) and 
another entity owning the "full" or consumer side of mailbox (waking up 
on full). An entity should not muck with the interrupts used by the 
opposite side.

One entity typically owns one shared interrupt only. For the 
BPMP/SCE/RCE/SPE HSP blocks the shared interrupt 0 is owned by the 
auxiliary processor itself, the shared interrupts 1..4 are connected to 
LIC and are available to other entities. The convention is to go through 
the interrupts 0..4 and then using the first available shared interrupt 
for both full and empty.

The interrupt functions should use a mask for mailboxes owned by kernel 
(in essence what the IE register should be for the HSP shared interrupt 
owned by the kernel) and serve only those mailboxes owned by kernel. 
Note that there is no reset for HSP in Xavier, and the IE register 
contents may be stale.

And lastly, if we want to support only Xavier and later, perhaps we 
should be more clear in the bindings? There are no mailbox-specific 
interrupt enable registers available on Parker and your design relies on 
them.

--Pekka

On 10/26/2018 02:16 PM, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> The Tegra HSP block supports 'shared mailboxes' that are simple 32-bit
> registers consisting of a FULL bit in MSB position and 31 bits of data.
> The hardware can be configured to trigger interrupts when a mailbox
> is empty or full. Add support for these shared mailboxes to the HSP
> driver.
>
> The initial use for the mailboxes is the Tegra Combined UART. For this
> purpose, we use interrupts to receive data, and spinning to wait for
> the transmit mailbox to be emptied to minimize unnecessary overhead.
>
> Based on work by Mikko Perttunen <mperttunen@xxxxxxxxxx>.
>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
>   drivers/mailbox/tegra-hsp.c | 476 +++++++++++++++++++++++++++++++-----
>   1 file changed, 415 insertions(+), 61 deletions(-)
>
> 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;
>   }