drivers/mailbox/hi6220-mailbox.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Hisilicon's Hi6220 mailbox driver
  *
  * Copyright (c) 2015 HiSilicon Limited.
  * Copyright (c) 2015 Linaro Limited.
  *
  * Author: Leo Yan <leo.yan@linaro.org>
  */

 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kfifo.h>
 #include <linux/mailbox_controller.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>

 #define MBOX_CHAN_MAX			32

 #define MBOX_TX				0x1

 /* Mailbox message length: 8 words */
 #define MBOX_MSG_LEN			8

 /* Mailbox Registers */
 #define MBOX_OFF(m)			(0x40 * (m))
 #define MBOX_MODE_REG(m)		(MBOX_OFF(m) + 0x0)
 #define MBOX_DATA_REG(m)		(MBOX_OFF(m) + 0x4)

 #define MBOX_STATE_MASK			(0xF << 4)
 #define MBOX_STATE_IDLE			(0x1 << 4)
 #define MBOX_STATE_TX			(0x2 << 4)
 #define MBOX_STATE_RX			(0x4 << 4)
 #define MBOX_STATE_ACK			(0x8 << 4)
 #define MBOX_ACK_CONFIG_MASK		(0x1 << 0)
 #define MBOX_ACK_AUTOMATIC		(0x1 << 0)
 #define MBOX_ACK_IRQ			(0x0 << 0)

 /* IPC registers */
 #define ACK_INT_RAW_REG(i)		((i) + 0x400)
 #define ACK_INT_MSK_REG(i)		((i) + 0x404)
 #define ACK_INT_STAT_REG(i)		((i) + 0x408)
 #define ACK_INT_CLR_REG(i)		((i) + 0x40c)
 #define ACK_INT_ENA_REG(i)		((i) + 0x500)
 #define ACK_INT_DIS_REG(i)		((i) + 0x504)
 #define DST_INT_RAW_REG(i)		((i) + 0x420)


 struct hi6220_mbox_chan {

 	/*
 	 * Description for channel's hardware info:
 	 *  - direction: tx or rx
 	 *  - dst irq: peer core's irq number
 	 *  - ack irq: local irq number
 	 *  - slot number
 	 */
 	unsigned int dir, dst_irq, ack_irq;
 	unsigned int slot;

 	struct hi6220_mbox *parent;
 };

 struct hi6220_mbox {
 	struct device *dev;

 	int irq;

 	/* flag of enabling tx's irq mode */
 	bool tx_irq_mode;

 	/* region for ipc event */
 	void __iomem *ipc;

 	/* region for mailbox */
 	void __iomem *base;

 	unsigned int chan_num;
 	struct hi6220_mbox_chan *mchan;

 	void *irq_map_chan[MBOX_CHAN_MAX];
 	struct mbox_chan *chan;
 	struct mbox_controller controller;
 };

 static void mbox_set_state(struct hi6220_mbox *mbox,
 			   unsigned int slot, u32 val)
 {
 	u32 status;

 	status = readl(mbox->base + MBOX_MODE_REG(slot));
 	status = (status & ~MBOX_STATE_MASK) | val;
 	writel(status, mbox->base + MBOX_MODE_REG(slot));
 }

 static void mbox_set_mode(struct hi6220_mbox *mbox,
 			  unsigned int slot, u32 val)
 {
 	u32 mode;

 	mode = readl(mbox->base + MBOX_MODE_REG(slot));
 	mode = (mode & ~MBOX_ACK_CONFIG_MASK) | val;
 	writel(mode, mbox->base + MBOX_MODE_REG(slot));
 }

 static bool hi6220_mbox_last_tx_done(struct mbox_chan *chan)
 {
 	struct hi6220_mbox_chan *mchan = chan->con_priv;
 	struct hi6220_mbox *mbox = mchan->parent;
 	u32 state;

 	/* Only set idle state for polling mode */
 	BUG_ON(mbox->tx_irq_mode);

 	state = readl(mbox->base + MBOX_MODE_REG(mchan->slot));
 	return ((state & MBOX_STATE_MASK) == MBOX_STATE_IDLE);
 }

 static int hi6220_mbox_send_data(struct mbox_chan *chan, void *msg)
 {
 	struct hi6220_mbox_chan *mchan = chan->con_priv;
 	struct hi6220_mbox *mbox = mchan->parent;
 	unsigned int slot = mchan->slot;
 	u32 *buf = msg;
 	int i;

 	/* indicate as a TX channel */
 	mchan->dir = MBOX_TX;

 	mbox_set_state(mbox, slot, MBOX_STATE_TX);

 	if (mbox->tx_irq_mode)
 		mbox_set_mode(mbox, slot, MBOX_ACK_IRQ);
 	else
 		mbox_set_mode(mbox, slot, MBOX_ACK_AUTOMATIC);

 	for (i = 0; i < MBOX_MSG_LEN; i++)
 		writel(buf[i], mbox->base + MBOX_DATA_REG(slot) + i * 4);

 	/* trigger remote request */
 	writel(BIT(mchan->dst_irq), DST_INT_RAW_REG(mbox->ipc));
 	return 0;
 }

 static irqreturn_t hi6220_mbox_interrupt(int irq, void *p)
 {
 	struct hi6220_mbox *mbox = p;
 	struct hi6220_mbox_chan *mchan;
 	struct mbox_chan *chan;
 	unsigned int state, intr_bit, i;
 	u32 msg[MBOX_MSG_LEN];

 	state = readl(ACK_INT_STAT_REG(mbox->ipc));
 	if (!state) {
 		dev_warn(mbox->dev, "%s: spurious interrupt\n",
 			 __func__);
 		return IRQ_HANDLED;
 	}

 	while (state) {
 		intr_bit = __ffs(state);
 		state &= (state - 1);

 		chan = mbox->irq_map_chan[intr_bit];
 		if (!chan) {
 			dev_warn(mbox->dev, "%s: unexpected irq vector %d\n",
 				 __func__, intr_bit);
 			continue;
 		}

 		mchan = chan->con_priv;
 		if (mchan->dir == MBOX_TX)
 			mbox_chan_txdone(chan, 0);
 		else {
 			for (i = 0; i < MBOX_MSG_LEN; i++)
 				msg[i] = readl(mbox->base +
 					MBOX_DATA_REG(mchan->slot) + i * 4);

 			mbox_chan_received_data(chan, (void *)msg);
 		}

 		/* clear IRQ source */
 		writel(BIT(mchan->ack_irq), ACK_INT_CLR_REG(mbox->ipc));
 		mbox_set_state(mbox, mchan->slot, MBOX_STATE_IDLE);
 	}

 	return IRQ_HANDLED;
 }

 static int hi6220_mbox_startup(struct mbox_chan *chan)
 {
 	struct hi6220_mbox_chan *mchan = chan->con_priv;
 	struct hi6220_mbox *mbox = mchan->parent;

 	mchan->dir = 0;

 	/* enable interrupt */
 	writel(BIT(mchan->ack_irq), ACK_INT_ENA_REG(mbox->ipc));
 	return 0;
 }

 static void hi6220_mbox_shutdown(struct mbox_chan *chan)
 {
 	struct hi6220_mbox_chan *mchan = chan->con_priv;
 	struct hi6220_mbox *mbox = mchan->parent;

 	/* disable interrupt */
 	writel(BIT(mchan->ack_irq), ACK_INT_DIS_REG(mbox->ipc));
 	mbox->irq_map_chan[mchan->ack_irq] = NULL;
 }

 static const struct mbox_chan_ops hi6220_mbox_ops = {
 	.send_data    = hi6220_mbox_send_data,
 	.startup      = hi6220_mbox_startup,
 	.shutdown     = hi6220_mbox_shutdown,
 	.last_tx_done = hi6220_mbox_last_tx_done,
 };

 static struct mbox_chan *hi6220_mbox_xlate(struct mbox_controller *controller,
 					   const struct of_phandle_args *spec)
 {
 	struct hi6220_mbox *mbox = dev_get_drvdata(controller->dev);
 	struct hi6220_mbox_chan *mchan;
 	struct mbox_chan *chan;
 	unsigned int i = spec->args[0];
 	unsigned int dst_irq = spec->args[1];
 	unsigned int ack_irq = spec->args[2];

 	/* Bounds checking */
 	if (i >= mbox->chan_num || dst_irq >= mbox->chan_num ||
 	    ack_irq >= mbox->chan_num) {
 		dev_err(mbox->dev,
 			"Invalid channel idx %d dst_irq %d ack_irq %d\n",
 			i, dst_irq, ack_irq);
 		return ERR_PTR(-EINVAL);
 	}

 	/* Is requested channel free? */
 	chan = &mbox->chan[i];
 	if (mbox->irq_map_chan[ack_irq] == (void *)chan) {
 		dev_err(mbox->dev, "Channel in use\n");
 		return ERR_PTR(-EBUSY);
 	}

 	mchan = chan->con_priv;
 	mchan->dst_irq = dst_irq;
 	mchan->ack_irq = ack_irq;

 	mbox->irq_map_chan[ack_irq] = (void *)chan;
 	return chan;
 }

 static const struct of_device_id hi6220_mbox_of_match[] = {
 	{ .compatible = "hisilicon,hi6220-mbox", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, hi6220_mbox_of_match);

 static int hi6220_mbox_probe(struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
 	struct device *dev = &pdev->dev;
 	struct hi6220_mbox *mbox;
 	int i, err;

 	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
 	if (!mbox)
 		return -ENOMEM;

 	mbox->dev = dev;
 	mbox->chan_num = MBOX_CHAN_MAX;
 	mbox->mchan = devm_kcalloc(dev,
 		mbox->chan_num, sizeof(*mbox->mchan), GFP_KERNEL);
 	if (!mbox->mchan)
 		return -ENOMEM;

 	mbox->chan = devm_kcalloc(dev,
 		mbox->chan_num, sizeof(*mbox->chan), GFP_KERNEL);
 	if (!mbox->chan)
 		return -ENOMEM;

 	mbox->irq = platform_get_irq(pdev, 0);
 	if (mbox->irq < 0)
 		return mbox->irq;

 	mbox->ipc = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mbox->ipc)) {
 		dev_err(dev, "ioremap ipc failed\n");
 		return PTR_ERR(mbox->ipc);
 	}

 	mbox->base = devm_platform_ioremap_resource(pdev, 1);
 	if (IS_ERR(mbox->base)) {
 		dev_err(dev, "ioremap buffer failed\n");
 		return PTR_ERR(mbox->base);
 	}

 	err = devm_request_irq(dev, mbox->irq, hi6220_mbox_interrupt, 0,
 			dev_name(dev), mbox);
 	if (err) {
 		dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
 			err);
 		return -ENODEV;
 	}

 	mbox->controller.dev = dev;
 	mbox->controller.chans = &mbox->chan[0];
 	mbox->controller.num_chans = mbox->chan_num;
 	mbox->controller.ops = &hi6220_mbox_ops;
 	mbox->controller.of_xlate = hi6220_mbox_xlate;

 	for (i = 0; i < mbox->chan_num; i++) {
 		mbox->chan[i].con_priv = &mbox->mchan[i];
 		mbox->irq_map_chan[i] = NULL;

 		mbox->mchan[i].parent = mbox;
 		mbox->mchan[i].slot   = i;
 	}

 	/* mask and clear all interrupt vectors */
 	writel(0x0,  ACK_INT_MSK_REG(mbox->ipc));
 	writel(~0x0, ACK_INT_CLR_REG(mbox->ipc));

 	/* use interrupt for tx's ack */
 	mbox->tx_irq_mode = !of_property_read_bool(node, "hi6220,mbox-tx-noirq");

 	if (mbox->tx_irq_mode)
 		mbox->controller.txdone_irq = true;
 	else {
 		mbox->controller.txdone_poll = true;
 		mbox->controller.txpoll_period = 5;
 	}

 	err = devm_mbox_controller_register(dev, &mbox->controller);
 	if (err) {
 		dev_err(dev, "Failed to register mailbox %d\n", err);
 		return err;
 	}

 	platform_set_drvdata(pdev, mbox);
 	dev_info(dev, "Mailbox enabled\n");
 	return 0;
 }

 static struct platform_driver hi6220_mbox_driver = {
 	.driver = {
 		.name = "hi6220-mbox",
 		.of_match_table = hi6220_mbox_of_match,
 	},
 	.probe	= hi6220_mbox_probe,
 };

 static int __init hi6220_mbox_init(void)
 {
 	return platform_driver_register(&hi6220_mbox_driver);
 }
 core_initcall(hi6220_mbox_init);

 static void __exit hi6220_mbox_exit(void)
 {
 	platform_driver_unregister(&hi6220_mbox_driver);
 }
 module_exit(hi6220_mbox_exit);

 MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
 MODULE_DESCRIPTION("Hi6220 mailbox driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Hisilicon's Hi6220 mailbox driver
	*
	* Copyright (c) 2015 HiSilicon Limited.
	* Copyright (c) 2015 Linaro Limited.
	*
	* Author: Leo Yan <leo.yan@linaro.org>
	*/

	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kfifo.h>
	#include <linux/mailbox_controller.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>

	#define MBOX_CHAN_MAX 32

	#define MBOX_TX 0x1

	/* Mailbox message length: 8 words */
	#define MBOX_MSG_LEN 8

	/* Mailbox Registers */
	#define MBOX_OFF(m) (0x40 * (m))
	#define MBOX_MODE_REG(m) (MBOX_OFF(m) + 0x0)
	#define MBOX_DATA_REG(m) (MBOX_OFF(m) + 0x4)

	#define MBOX_STATE_MASK (0xF << 4)
	#define MBOX_STATE_IDLE (0x1 << 4)
	#define MBOX_STATE_TX (0x2 << 4)
	#define MBOX_STATE_RX (0x4 << 4)
	#define MBOX_STATE_ACK (0x8 << 4)
	#define MBOX_ACK_CONFIG_MASK (0x1 << 0)
	#define MBOX_ACK_AUTOMATIC (0x1 << 0)
	#define MBOX_ACK_IRQ (0x0 << 0)

	/* IPC registers */
	#define ACK_INT_RAW_REG(i) ((i) + 0x400)
	#define ACK_INT_MSK_REG(i) ((i) + 0x404)
	#define ACK_INT_STAT_REG(i) ((i) + 0x408)
	#define ACK_INT_CLR_REG(i) ((i) + 0x40c)
	#define ACK_INT_ENA_REG(i) ((i) + 0x500)
	#define ACK_INT_DIS_REG(i) ((i) + 0x504)
	#define DST_INT_RAW_REG(i) ((i) + 0x420)


	struct hi6220_mbox_chan {

	/*
	* Description for channel's hardware info:
	* - direction: tx or rx
	* - dst irq: peer core's irq number
	* - ack irq: local irq number
	* - slot number
	*/
	unsigned int dir, dst_irq, ack_irq;
	unsigned int slot;

	struct hi6220_mbox *parent;
	};

	struct hi6220_mbox {
	struct device *dev;

	int irq;

	/* flag of enabling tx's irq mode */
	bool tx_irq_mode;

	/* region for ipc event */
	void __iomem *ipc;

	/* region for mailbox */
	void __iomem *base;

	unsigned int chan_num;
	struct hi6220_mbox_chan *mchan;

	void *irq_map_chan[MBOX_CHAN_MAX];
	struct mbox_chan *chan;
	struct mbox_controller controller;
	};

	static void mbox_set_state(struct hi6220_mbox *mbox,
	unsigned int slot, u32 val)
	{
	u32 status;

	status = readl(mbox->base + MBOX_MODE_REG(slot));
	status = (status & ~MBOX_STATE_MASK) \| val;
	writel(status, mbox->base + MBOX_MODE_REG(slot));
	}

	static void mbox_set_mode(struct hi6220_mbox *mbox,
	unsigned int slot, u32 val)
	{
	u32 mode;

	mode = readl(mbox->base + MBOX_MODE_REG(slot));
	mode = (mode & ~MBOX_ACK_CONFIG_MASK) \| val;
	writel(mode, mbox->base + MBOX_MODE_REG(slot));
	}

	static bool hi6220_mbox_last_tx_done(struct mbox_chan *chan)
	{
	struct hi6220_mbox_chan *mchan = chan->con_priv;
	struct hi6220_mbox *mbox = mchan->parent;
	u32 state;

	/* Only set idle state for polling mode */
	BUG_ON(mbox->tx_irq_mode);

	state = readl(mbox->base + MBOX_MODE_REG(mchan->slot));
	return ((state & MBOX_STATE_MASK) == MBOX_STATE_IDLE);
	}

	static int hi6220_mbox_send_data(struct mbox_chan chan, void msg)
	{
	struct hi6220_mbox_chan *mchan = chan->con_priv;
	struct hi6220_mbox *mbox = mchan->parent;
	unsigned int slot = mchan->slot;
	u32 *buf = msg;
	int i;

	/* indicate as a TX channel */
	mchan->dir = MBOX_TX;

	mbox_set_state(mbox, slot, MBOX_STATE_TX);

	if (mbox->tx_irq_mode)
	mbox_set_mode(mbox, slot, MBOX_ACK_IRQ);
	else
	mbox_set_mode(mbox, slot, MBOX_ACK_AUTOMATIC);

	for (i = 0; i < MBOX_MSG_LEN; i++)
	writel(buf[i], mbox->base + MBOX_DATA_REG(slot) + i * 4);

	/* trigger remote request */
	writel(BIT(mchan->dst_irq), DST_INT_RAW_REG(mbox->ipc));
	return 0;
	}

	static irqreturn_t hi6220_mbox_interrupt(int irq, void *p)
	{
	struct hi6220_mbox *mbox = p;
	struct hi6220_mbox_chan *mchan;
	struct mbox_chan *chan;
	unsigned int state, intr_bit, i;
	u32 msg[MBOX_MSG_LEN];

	state = readl(ACK_INT_STAT_REG(mbox->ipc));
	if (!state) {
	dev_warn(mbox->dev, "%s: spurious interrupt\n",
	__func__);
	return IRQ_HANDLED;
	}

	while (state) {
	intr_bit = __ffs(state);
	state &= (state - 1);

	chan = mbox->irq_map_chan[intr_bit];
	if (!chan) {
	dev_warn(mbox->dev, "%s: unexpected irq vector %d\n",
	__func__, intr_bit);
	continue;
	}

	mchan = chan->con_priv;
	if (mchan->dir == MBOX_TX)
	mbox_chan_txdone(chan, 0);
	else {
	for (i = 0; i < MBOX_MSG_LEN; i++)
	msg[i] = readl(mbox->base +
	MBOX_DATA_REG(mchan->slot) + i * 4);

	mbox_chan_received_data(chan, (void *)msg);
	}

	/* clear IRQ source */
	writel(BIT(mchan->ack_irq), ACK_INT_CLR_REG(mbox->ipc));
	mbox_set_state(mbox, mchan->slot, MBOX_STATE_IDLE);
	}

	return IRQ_HANDLED;
	}

	static int hi6220_mbox_startup(struct mbox_chan *chan)
	{
	struct hi6220_mbox_chan *mchan = chan->con_priv;
	struct hi6220_mbox *mbox = mchan->parent;

	mchan->dir = 0;

	/* enable interrupt */
	writel(BIT(mchan->ack_irq), ACK_INT_ENA_REG(mbox->ipc));
	return 0;
	}

	static void hi6220_mbox_shutdown(struct mbox_chan *chan)
	{
	struct hi6220_mbox_chan *mchan = chan->con_priv;
	struct hi6220_mbox *mbox = mchan->parent;

	/* disable interrupt */
	writel(BIT(mchan->ack_irq), ACK_INT_DIS_REG(mbox->ipc));
	mbox->irq_map_chan[mchan->ack_irq] = NULL;
	}

	static const struct mbox_chan_ops hi6220_mbox_ops = {
	.send_data = hi6220_mbox_send_data,
	.startup = hi6220_mbox_startup,
	.shutdown = hi6220_mbox_shutdown,
	.last_tx_done = hi6220_mbox_last_tx_done,
	};

	static struct mbox_chan hi6220_mbox_xlate(struct mbox_controller controller,
	const struct of_phandle_args *spec)
	{
	struct hi6220_mbox *mbox = dev_get_drvdata(controller->dev);
	struct hi6220_mbox_chan *mchan;
	struct mbox_chan *chan;
	unsigned int i = spec->args[0];
	unsigned int dst_irq = spec->args[1];
	unsigned int ack_irq = spec->args[2];

	/* Bounds checking */
	if (i >= mbox->chan_num \|\| dst_irq >= mbox->chan_num \|\|
	ack_irq >= mbox->chan_num) {
	dev_err(mbox->dev,
	"Invalid channel idx %d dst_irq %d ack_irq %d\n",
	i, dst_irq, ack_irq);
	return ERR_PTR(-EINVAL);
	}

	/* Is requested channel free? */
	chan = &mbox->chan[i];
	if (mbox->irq_map_chan[ack_irq] == (void *)chan) {
	dev_err(mbox->dev, "Channel in use\n");
	return ERR_PTR(-EBUSY);
	}

	mchan = chan->con_priv;
	mchan->dst_irq = dst_irq;
	mchan->ack_irq = ack_irq;

	mbox->irq_map_chan[ack_irq] = (void *)chan;
	return chan;
	}

	static const struct of_device_id hi6220_mbox_of_match[] = {
	{ .compatible = "hisilicon,hi6220-mbox", },
	{},
	};
	MODULE_DEVICE_TABLE(of, hi6220_mbox_of_match);

	static int hi6220_mbox_probe(struct platform_device *pdev)
	{
	struct device_node *node = pdev->dev.of_node;
	struct device *dev = &pdev->dev;
	struct hi6220_mbox *mbox;
	int i, err;

	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
	if (!mbox)
	return -ENOMEM;

	mbox->dev = dev;
	mbox->chan_num = MBOX_CHAN_MAX;
	mbox->mchan = devm_kcalloc(dev,
	mbox->chan_num, sizeof(*mbox->mchan), GFP_KERNEL);
	if (!mbox->mchan)
	return -ENOMEM;

	mbox->chan = devm_kcalloc(dev,
	mbox->chan_num, sizeof(*mbox->chan), GFP_KERNEL);
	if (!mbox->chan)
	return -ENOMEM;

	mbox->irq = platform_get_irq(pdev, 0);
	if (mbox->irq < 0)
	return mbox->irq;

	mbox->ipc = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(mbox->ipc)) {
	dev_err(dev, "ioremap ipc failed\n");
	return PTR_ERR(mbox->ipc);
	}

	mbox->base = devm_platform_ioremap_resource(pdev, 1);
	if (IS_ERR(mbox->base)) {
	dev_err(dev, "ioremap buffer failed\n");
	return PTR_ERR(mbox->base);
	}

	err = devm_request_irq(dev, mbox->irq, hi6220_mbox_interrupt, 0,
	dev_name(dev), mbox);
	if (err) {
	dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
	err);
	return -ENODEV;
	}

	mbox->controller.dev = dev;
	mbox->controller.chans = &mbox->chan[0];
	mbox->controller.num_chans = mbox->chan_num;
	mbox->controller.ops = &hi6220_mbox_ops;
	mbox->controller.of_xlate = hi6220_mbox_xlate;

	for (i = 0; i < mbox->chan_num; i++) {
	mbox->chan[i].con_priv = &mbox->mchan[i];
	mbox->irq_map_chan[i] = NULL;

	mbox->mchan[i].parent = mbox;
	mbox->mchan[i].slot = i;
	}

	/* mask and clear all interrupt vectors */
	writel(0x0, ACK_INT_MSK_REG(mbox->ipc));
	writel(~0x0, ACK_INT_CLR_REG(mbox->ipc));

	/* use interrupt for tx's ack */
	mbox->tx_irq_mode = !of_property_read_bool(node, "hi6220,mbox-tx-noirq");

	if (mbox->tx_irq_mode)
	mbox->controller.txdone_irq = true;
	else {
	mbox->controller.txdone_poll = true;
	mbox->controller.txpoll_period = 5;
	}

	err = devm_mbox_controller_register(dev, &mbox->controller);
	if (err) {
	dev_err(dev, "Failed to register mailbox %d\n", err);
	return err;
	}

	platform_set_drvdata(pdev, mbox);
	dev_info(dev, "Mailbox enabled\n");
	return 0;
	}

	static struct platform_driver hi6220_mbox_driver = {
	.driver = {
	.name = "hi6220-mbox",
	.of_match_table = hi6220_mbox_of_match,
	},
	.probe = hi6220_mbox_probe,
	};

	static int __init hi6220_mbox_init(void)
	{
	return platform_driver_register(&hi6220_mbox_driver);
	}
	core_initcall(hi6220_mbox_init);

	static void __exit hi6220_mbox_exit(void)
	{
	platform_driver_unregister(&hi6220_mbox_driver);
	}
	module_exit(hi6220_mbox_exit);

	MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");
	MODULE_DESCRIPTION("Hi6220 mailbox driver");
	MODULE_LICENSE("GPL v2");