drivers/mailbox/mailbox-altera.c - linux/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright Altera Corporation (C) 2013-2014. All rights reserved
  */

 #include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/mailbox_controller.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>

 #define DRIVER_NAME	"altera-mailbox"

 #define MAILBOX_CMD_REG			0x00
 #define MAILBOX_PTR_REG			0x04
 #define MAILBOX_STS_REG			0x08
 #define MAILBOX_INTMASK_REG		0x0C

 #define INT_PENDING_MSK			0x1
 #define INT_SPACE_MSK			0x2

 #define STS_PENDING_MSK			0x1
 #define STS_FULL_MSK			0x2
 #define STS_FULL_OFT			0x1

 #define MBOX_PENDING(status)	(((status) & STS_PENDING_MSK))
 #define MBOX_FULL(status)	(((status) & STS_FULL_MSK) >> STS_FULL_OFT)

 enum altera_mbox_msg {
 	MBOX_CMD = 0,
 	MBOX_PTR,
 };

 #define MBOX_POLLING_MS		5	/* polling interval 5ms */

 struct altera_mbox {
 	bool is_sender;		/* 1-sender, 0-receiver */
 	bool intr_mode;
 	int irq;
 	void __iomem *mbox_base;
 	struct device *dev;
 	struct mbox_controller controller;

 	/* If the controller supports only RX polling mode */
 	struct timer_list rxpoll_timer;
 	struct mbox_chan *chan;
 };

 static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan)
 {
 	if (!chan || !chan->con_priv)
 		return NULL;

 	return (struct altera_mbox *)chan->con_priv;
 }

 static inline int altera_mbox_full(struct altera_mbox *mbox)
 {
 	u32 status;

 	status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
 	return MBOX_FULL(status);
 }

 static inline int altera_mbox_pending(struct altera_mbox *mbox)
 {
 	u32 status;

 	status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
 	return MBOX_PENDING(status);
 }

 static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
 {
 	u32 mask;

 	mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
 	if (enable)
 		mask |= INT_PENDING_MSK;
 	else
 		mask &= ~INT_PENDING_MSK;
 	writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
 }

 static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
 {
 	u32 mask;

 	mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
 	if (enable)
 		mask |= INT_SPACE_MSK;
 	else
 		mask &= ~INT_SPACE_MSK;
 	writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
 }

 static bool altera_mbox_is_sender(struct altera_mbox *mbox)
 {
 	u32 reg;
 	/* Write a magic number to PTR register and read back this register.
 	 * This register is read-write if it is a sender.
 	 */
 	#define MBOX_MAGIC	0xA5A5AA55
 	writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
 	reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
 	if (reg == MBOX_MAGIC) {
 		/* Clear to 0 */
 		writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
 		return true;
 	}
 	return false;
 }

 static void altera_mbox_rx_data(struct mbox_chan *chan)
 {
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 	u32 data[2];

 	if (altera_mbox_pending(mbox)) {
 		data[MBOX_PTR] =
 			readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
 		data[MBOX_CMD] =
 			readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
 		mbox_chan_received_data(chan, (void *)data);
 	}
 }

 static void altera_mbox_poll_rx(struct timer_list *t)
 {
 	struct altera_mbox *mbox = from_timer(mbox, t, rxpoll_timer);

 	altera_mbox_rx_data(mbox->chan);

 	mod_timer(&mbox->rxpoll_timer,
 		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
 }

 static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p)
 {
 	struct mbox_chan *chan = (struct mbox_chan *)p;
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

 	altera_mbox_tx_intmask(mbox, false);
 	mbox_chan_txdone(chan, 0);

 	return IRQ_HANDLED;
 }

 static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p)
 {
 	struct mbox_chan *chan = (struct mbox_chan *)p;

 	altera_mbox_rx_data(chan);
 	return IRQ_HANDLED;
 }

 static int altera_mbox_startup_sender(struct mbox_chan *chan)
 {
 	int ret;
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

 	if (mbox->intr_mode) {
 		ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,
 				  DRIVER_NAME, chan);
 		if (unlikely(ret)) {
 			dev_err(mbox->dev,
 				"failed to register mailbox interrupt:%d\n",
 				ret);
 			return ret;
 		}
 	}

 	return 0;
 }

 static int altera_mbox_startup_receiver(struct mbox_chan *chan)
 {
 	int ret;
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

 	if (mbox->intr_mode) {
 		ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
 				  DRIVER_NAME, chan);
 		if (unlikely(ret)) {
 			mbox->intr_mode = false;
 			goto polling; /* use polling if failed */
 		}

 		altera_mbox_rx_intmask(mbox, true);
 		return 0;
 	}

 polling:
 	/* Setup polling timer */
 	mbox->chan = chan;
 	timer_setup(&mbox->rxpoll_timer, altera_mbox_poll_rx, 0);
 	mod_timer(&mbox->rxpoll_timer,
 		  jiffies + msecs_to_jiffies(MBOX_POLLING_MS));

 	return 0;
 }

 static int altera_mbox_send_data(struct mbox_chan *chan, void *data)
 {
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 	u32 *udata = (u32 *)data;

 	if (!mbox || !data)
 		return -EINVAL;
 	if (!mbox->is_sender) {
 		dev_warn(mbox->dev,
 			 "failed to send. This is receiver mailbox.\n");
 		return -EINVAL;
 	}

 	if (altera_mbox_full(mbox))
 		return -EBUSY;

 	/* Enable interrupt before send */
 	if (mbox->intr_mode)
 		altera_mbox_tx_intmask(mbox, true);

 	/* Pointer register must write before command register */
 	writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
 	writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG);

 	return 0;
 }

 static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
 {
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

 	/* Return false if mailbox is full */
 	return altera_mbox_full(mbox) ? false : true;
 }

 static bool altera_mbox_peek_data(struct mbox_chan *chan)
 {
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

 	return altera_mbox_pending(mbox) ? true : false;
 }

 static int altera_mbox_startup(struct mbox_chan *chan)
 {
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
 	int ret = 0;

 	if (!mbox)
 		return -EINVAL;

 	if (mbox->is_sender)
 		ret = altera_mbox_startup_sender(chan);
 	else
 		ret = altera_mbox_startup_receiver(chan);

 	return ret;
 }

 static void altera_mbox_shutdown(struct mbox_chan *chan)
 {
 	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

 	if (mbox->intr_mode) {
 		/* Unmask all interrupt masks */
 		writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
 		free_irq(mbox->irq, chan);
 	} else if (!mbox->is_sender) {
 		del_timer_sync(&mbox->rxpoll_timer);
 	}
 }

 static const struct mbox_chan_ops altera_mbox_ops = {
 	.send_data = altera_mbox_send_data,
 	.startup = altera_mbox_startup,
 	.shutdown = altera_mbox_shutdown,
 	.last_tx_done = altera_mbox_last_tx_done,
 	.peek_data = altera_mbox_peek_data,
 };

 static int altera_mbox_probe(struct platform_device *pdev)
 {
 	struct altera_mbox *mbox;
 	struct resource	*regs;
 	struct mbox_chan *chans;
 	int ret;

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

 	/* Allocated one channel */
 	chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
 	if (!chans)
 		return -ENOMEM;

 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);

 	mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
 	if (IS_ERR(mbox->mbox_base))
 		return PTR_ERR(mbox->mbox_base);

 	/* Check is it a sender or receiver? */
 	mbox->is_sender = altera_mbox_is_sender(mbox);

 	mbox->irq = platform_get_irq(pdev, 0);
 	if (mbox->irq >= 0)
 		mbox->intr_mode = true;

 	mbox->dev = &pdev->dev;

 	/* Hardware supports only one channel. */
 	chans[0].con_priv = mbox;
 	mbox->controller.dev = mbox->dev;
 	mbox->controller.num_chans = 1;
 	mbox->controller.chans = chans;
 	mbox->controller.ops = &altera_mbox_ops;

 	if (mbox->is_sender) {
 		if (mbox->intr_mode) {
 			mbox->controller.txdone_irq = true;
 		} else {
 			mbox->controller.txdone_poll = true;
 			mbox->controller.txpoll_period = MBOX_POLLING_MS;
 		}
 	}

 	ret = devm_mbox_controller_register(&pdev->dev, &mbox->controller);
 	if (ret) {
 		dev_err(&pdev->dev, "Register mailbox failed\n");
 		goto err;
 	}

 	platform_set_drvdata(pdev, mbox);
 err:
 	return ret;
 }

 static const struct of_device_id altera_mbox_match[] = {
 	{ .compatible = "altr,mailbox-1.0" },
 	{ /* Sentinel */ }
 };

 MODULE_DEVICE_TABLE(of, altera_mbox_match);

 static struct platform_driver altera_mbox_driver = {
 	.probe	= altera_mbox_probe,
 	.driver	= {
 		.name	= DRIVER_NAME,
 		.of_match_table	= altera_mbox_match,
 	},
 };

 module_platform_driver(altera_mbox_driver);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Altera mailbox specific functions");
 MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
 MODULE_ALIAS("platform:altera-mailbox");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright Altera Corporation (C) 2013-2014. All rights reserved
	*/

	#include <linux/device.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/mailbox_controller.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>

	#define DRIVER_NAME "altera-mailbox"

	#define MAILBOX_CMD_REG 0x00
	#define MAILBOX_PTR_REG 0x04
	#define MAILBOX_STS_REG 0x08
	#define MAILBOX_INTMASK_REG 0x0C

	#define INT_PENDING_MSK 0x1
	#define INT_SPACE_MSK 0x2

	#define STS_PENDING_MSK 0x1
	#define STS_FULL_MSK 0x2
	#define STS_FULL_OFT 0x1

	#define MBOX_PENDING(status) (((status) & STS_PENDING_MSK))
	#define MBOX_FULL(status) (((status) & STS_FULL_MSK) >> STS_FULL_OFT)

	enum altera_mbox_msg {
	MBOX_CMD = 0,
	MBOX_PTR,
	};

	#define MBOX_POLLING_MS 5 /* polling interval 5ms */

	struct altera_mbox {
	bool is_sender; /* 1-sender, 0-receiver */
	bool intr_mode;
	int irq;
	void __iomem *mbox_base;
	struct device *dev;
	struct mbox_controller controller;

	/* If the controller supports only RX polling mode */
	struct timer_list rxpoll_timer;
	struct mbox_chan *chan;
	};

	static struct altera_mbox mbox_chan_to_altera_mbox(struct mbox_chan chan)
	{
	if (!chan \|\| !chan->con_priv)
	return NULL;

	return (struct altera_mbox *)chan->con_priv;
	}

	static inline int altera_mbox_full(struct altera_mbox *mbox)
	{
	u32 status;

	status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
	return MBOX_FULL(status);
	}

	static inline int altera_mbox_pending(struct altera_mbox *mbox)
	{
	u32 status;

	status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
	return MBOX_PENDING(status);
	}

	static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
	{
	u32 mask;

	mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
	if (enable)
	mask \|= INT_PENDING_MSK;
	else
	mask &= ~INT_PENDING_MSK;
	writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
	}

	static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
	{
	u32 mask;

	mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
	if (enable)
	mask \|= INT_SPACE_MSK;
	else
	mask &= ~INT_SPACE_MSK;
	writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
	}

	static bool altera_mbox_is_sender(struct altera_mbox *mbox)
	{
	u32 reg;
	/* Write a magic number to PTR register and read back this register.
	* This register is read-write if it is a sender.
	*/
	#define MBOX_MAGIC 0xA5A5AA55
	writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
	reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
	if (reg == MBOX_MAGIC) {
	/* Clear to 0 */
	writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
	return true;
	}
	return false;
	}

	static void altera_mbox_rx_data(struct mbox_chan *chan)
	{
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
	u32 data[2];

	if (altera_mbox_pending(mbox)) {
	data[MBOX_PTR] =
	readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
	data[MBOX_CMD] =
	readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
	mbox_chan_received_data(chan, (void *)data);
	}
	}

	static void altera_mbox_poll_rx(struct timer_list *t)
	{
	struct altera_mbox *mbox = from_timer(mbox, t, rxpoll_timer);

	altera_mbox_rx_data(mbox->chan);

	mod_timer(&mbox->rxpoll_timer,
	jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
	}

	static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p)
	{
	struct mbox_chan chan = (struct mbox_chan )p;
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

	altera_mbox_tx_intmask(mbox, false);
	mbox_chan_txdone(chan, 0);

	return IRQ_HANDLED;
	}

	static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p)
	{
	struct mbox_chan chan = (struct mbox_chan )p;

	altera_mbox_rx_data(chan);
	return IRQ_HANDLED;
	}

	static int altera_mbox_startup_sender(struct mbox_chan *chan)
	{
	int ret;
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

	if (mbox->intr_mode) {
	ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,
	DRIVER_NAME, chan);
	if (unlikely(ret)) {
	dev_err(mbox->dev,
	"failed to register mailbox interrupt:%d\n",
	ret);
	return ret;
	}
	}

	return 0;
	}

	static int altera_mbox_startup_receiver(struct mbox_chan *chan)
	{
	int ret;
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

	if (mbox->intr_mode) {
	ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
	DRIVER_NAME, chan);
	if (unlikely(ret)) {
	mbox->intr_mode = false;
	goto polling; /* use polling if failed */
	}

	altera_mbox_rx_intmask(mbox, true);
	return 0;
	}

	polling:
	/* Setup polling timer */
	mbox->chan = chan;
	timer_setup(&mbox->rxpoll_timer, altera_mbox_poll_rx, 0);
	mod_timer(&mbox->rxpoll_timer,
	jiffies + msecs_to_jiffies(MBOX_POLLING_MS));

	return 0;
	}

	static int altera_mbox_send_data(struct mbox_chan chan, void data)
	{
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
	u32 udata = (u32 )data;

	if (!mbox \|\| !data)
	return -EINVAL;
	if (!mbox->is_sender) {
	dev_warn(mbox->dev,
	"failed to send. This is receiver mailbox.\n");
	return -EINVAL;
	}

	if (altera_mbox_full(mbox))
	return -EBUSY;

	/* Enable interrupt before send */
	if (mbox->intr_mode)
	altera_mbox_tx_intmask(mbox, true);

	/* Pointer register must write before command register */
	writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
	writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG);

	return 0;
	}

	static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
	{
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

	/* Return false if mailbox is full */
	return altera_mbox_full(mbox) ? false : true;
	}

	static bool altera_mbox_peek_data(struct mbox_chan *chan)
	{
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

	return altera_mbox_pending(mbox) ? true : false;
	}

	static int altera_mbox_startup(struct mbox_chan *chan)
	{
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
	int ret = 0;

	if (!mbox)
	return -EINVAL;

	if (mbox->is_sender)
	ret = altera_mbox_startup_sender(chan);
	else
	ret = altera_mbox_startup_receiver(chan);

	return ret;
	}

	static void altera_mbox_shutdown(struct mbox_chan *chan)
	{
	struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);

	if (mbox->intr_mode) {
	/* Unmask all interrupt masks */
	writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
	free_irq(mbox->irq, chan);
	} else if (!mbox->is_sender) {
	del_timer_sync(&mbox->rxpoll_timer);
	}
	}

	static const struct mbox_chan_ops altera_mbox_ops = {
	.send_data = altera_mbox_send_data,
	.startup = altera_mbox_startup,
	.shutdown = altera_mbox_shutdown,
	.last_tx_done = altera_mbox_last_tx_done,
	.peek_data = altera_mbox_peek_data,
	};

	static int altera_mbox_probe(struct platform_device *pdev)
	{
	struct altera_mbox *mbox;
	struct resource *regs;
	struct mbox_chan *chans;
	int ret;

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

	/* Allocated one channel */
	chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
	if (!chans)
	return -ENOMEM;

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
	if (IS_ERR(mbox->mbox_base))
	return PTR_ERR(mbox->mbox_base);

	/* Check is it a sender or receiver? */
	mbox->is_sender = altera_mbox_is_sender(mbox);

	mbox->irq = platform_get_irq(pdev, 0);
	if (mbox->irq >= 0)
	mbox->intr_mode = true;

	mbox->dev = &pdev->dev;

	/* Hardware supports only one channel. */
	chans[0].con_priv = mbox;
	mbox->controller.dev = mbox->dev;
	mbox->controller.num_chans = 1;
	mbox->controller.chans = chans;
	mbox->controller.ops = &altera_mbox_ops;

	if (mbox->is_sender) {
	if (mbox->intr_mode) {
	mbox->controller.txdone_irq = true;
	} else {
	mbox->controller.txdone_poll = true;
	mbox->controller.txpoll_period = MBOX_POLLING_MS;
	}
	}

	ret = devm_mbox_controller_register(&pdev->dev, &mbox->controller);
	if (ret) {
	dev_err(&pdev->dev, "Register mailbox failed\n");
	goto err;
	}

	platform_set_drvdata(pdev, mbox);
	err:
	return ret;
	}

	static const struct of_device_id altera_mbox_match[] = {
	{ .compatible = "altr,mailbox-1.0" },
	{ /* Sentinel */ }
	};

	MODULE_DEVICE_TABLE(of, altera_mbox_match);

	static struct platform_driver altera_mbox_driver = {
	.probe = altera_mbox_probe,
	.driver = {
	.name = DRIVER_NAME,
	.of_match_table = altera_mbox_match,
	},
	};

	module_platform_driver(altera_mbox_driver);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("Altera mailbox specific functions");
	MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
	MODULE_ALIAS("platform:altera-mailbox");