text: /*
   * OMAP mailbox driver
   *
   * Copyright (C) 2006-2009 Nokia Corporation. All rights reserved.
   * Copyright (C) 2013-2014 Texas Instruments Inc.
   *
   * Contact: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
   *          Suman Anna <s-anna@ti.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * version 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   *
   */
  
  #include <linux/interrupt.h>
  #include <linux/spinlock.h>
  #include <linux/mutex.h>
  #include <linux/slab.h>
  #include <linux/kfifo.h>
  #include <linux/err.h>
  #include <linux/module.h>
  #include <linux/of_device.h>
  #include <linux/platform_device.h>
  #include <linux/pm_runtime.h>
  #include <linux/platform_data/mailbox-omap.h>
  #include <linux/omap-mailbox.h>
  #include <linux/mailbox_controller.h>
  #include <linux/mailbox_client.h>
  
  #include "mailbox.h"
  
  #define MAILBOX_REVISION		0x000
  #define MAILBOX_MESSAGE(m)		(0x040 + 4 * (m))
  #define MAILBOX_FIFOSTATUS(m)		(0x080 + 4 * (m))
  #define MAILBOX_MSGSTATUS(m)		(0x0c0 + 4 * (m))
  
  #define OMAP2_MAILBOX_IRQSTATUS(u)	(0x100 + 8 * (u))
  #define OMAP2_MAILBOX_IRQENABLE(u)	(0x104 + 8 * (u))
  
  #define OMAP4_MAILBOX_IRQSTATUS(u)	(0x104 + 0x10 * (u))
  #define OMAP4_MAILBOX_IRQENABLE(u)	(0x108 + 0x10 * (u))
  #define OMAP4_MAILBOX_IRQENABLE_CLR(u)	(0x10c + 0x10 * (u))
  
  #define MAILBOX_IRQSTATUS(type, u)	(type ? OMAP4_MAILBOX_IRQSTATUS(u) : \
  						OMAP2_MAILBOX_IRQSTATUS(u))
  #define MAILBOX_IRQENABLE(type, u)	(type ? OMAP4_MAILBOX_IRQENABLE(u) : \
  						OMAP2_MAILBOX_IRQENABLE(u))
  #define MAILBOX_IRQDISABLE(type, u)	(type ? OMAP4_MAILBOX_IRQENABLE_CLR(u) \
  						: OMAP2_MAILBOX_IRQENABLE(u))
  
  #define MAILBOX_IRQ_NEWMSG(m)		(1 << (2 * (m)))
  #define MAILBOX_IRQ_NOTFULL(m)		(1 << (2 * (m) + 1))
  
  #define MBOX_REG_SIZE			0x120
  
  #define OMAP4_MBOX_REG_SIZE		0x130
  
  #define MBOX_NR_REGS			(MBOX_REG_SIZE / sizeof(u32))
  #define OMAP4_MBOX_NR_REGS		(OMAP4_MBOX_REG_SIZE / sizeof(u32))
  
  struct omap_mbox_fifo {
  	unsigned long msg;
  	unsigned long fifo_stat;
  	unsigned long msg_stat;
  	unsigned long irqenable;
  	unsigned long irqstatus;
  	unsigned long irqdisable;
  	u32 intr_bit;
  };
  
  struct omap_mbox_queue {
  	spinlock_t		lock;
  	struct kfifo		fifo;
  	struct work_struct	work;
  	struct omap_mbox	*mbox;
  	bool full;
  };
  
  struct omap_mbox_device {
  	struct device *dev;
  	struct mutex cfg_lock;
  	void __iomem *mbox_base;
  	u32 num_users;
  	u32 num_fifos;
  	struct omap_mbox **mboxes;
  	struct mbox_controller controller;
  	struct list_head elem;
  };
  
  struct omap_mbox_fifo_info {
  	int tx_id;
  	int tx_usr;
  	int tx_irq;
  
  	int rx_id;
  	int rx_usr;
  	int rx_irq;
  
  	const char *name;
  	bool send_no_irq;
  };
  
  struct omap_mbox {
  	const char		*name;
  	int			irq;
  	struct omap_mbox_queue	*rxq;
  	struct device		*dev;
  	struct omap_mbox_device *parent;
  	struct omap_mbox_fifo	tx_fifo;
  	struct omap_mbox_fifo	rx_fifo;
  	u32			ctx[OMAP4_MBOX_NR_REGS];
  	u32			intr_type;
  	struct mbox_chan	*chan;
  	bool			send_no_irq;
  };
  
  /* global variables for the mailbox devices */
  static DEFINE_MUTEX(omap_mbox_devices_lock);
  static LIST_HEAD(omap_mbox_devices);
  
  static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE;
  module_param(mbox_kfifo_size, uint, S_IRUGO);
  MODULE_PARM_DESC(mbox_kfifo_size, "Size of omap's mailbox kfifo (bytes)");
  
  static struct omap_mbox *mbox_chan_to_omap_mbox(struct mbox_chan *chan)
  {
  	if (!chan || !chan->con_priv)
  		return NULL;
  
  	return (struct omap_mbox *)chan->con_priv;
  }
  
  static inline
  unsigned int mbox_read_reg(struct omap_mbox_device *mdev, size_t ofs)
  {
  	return __raw_readl(mdev->mbox_base + ofs);
  }
  
  static inline
  void mbox_write_reg(struct omap_mbox_device *mdev, u32 val, size_t ofs)
  {
  	__raw_writel(val, mdev->mbox_base + ofs);
  }
  
  /* Mailbox FIFO handle functions */
  static mbox_msg_t mbox_fifo_read(struct omap_mbox *mbox)
  {
  	struct omap_mbox_fifo *fifo = &mbox->rx_fifo;
  	return (mbox_msg_t) mbox_read_reg(mbox->parent, fifo->msg);
  }
  
  static void mbox_fifo_write(struct omap_mbox *mbox, mbox_msg_t msg)
  {
  	struct omap_mbox_fifo *fifo = &mbox->tx_fifo;
  	mbox_write_reg(mbox->parent, msg, fifo->msg);
  }
  
  static int mbox_fifo_empty(struct omap_mbox *mbox)
  {
  	struct omap_mbox_fifo *fifo = &mbox->rx_fifo;
  	return (mbox_read_reg(mbox->parent, fifo->msg_stat) == 0);
  }
  
  static int mbox_fifo_full(struct omap_mbox *mbox)
  {
  	struct omap_mbox_fifo *fifo = &mbox->tx_fifo;
  	return mbox_read_reg(mbox->parent, fifo->fifo_stat);
  }
  
  /* Mailbox IRQ handle functions */
  static void ack_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
  {
  	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
  				&mbox->tx_fifo : &mbox->rx_fifo;
  	u32 bit = fifo->intr_bit;
  	u32 irqstatus = fifo->irqstatus;
  
  	mbox_write_reg(mbox->parent, bit, irqstatus);
  
  	/* Flush posted write for irq status to avoid spurious interrupts */
  	mbox_read_reg(mbox->parent, irqstatus);
  }
  
  static int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
  {
  	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
  				&mbox->tx_fifo : &mbox->rx_fifo;
  	u32 bit = fifo->intr_bit;
  	u32 irqenable = fifo->irqenable;
  	u32 irqstatus = fifo->irqstatus;
  
  	u32 enable = mbox_read_reg(mbox->parent, irqenable);
  	u32 status = mbox_read_reg(mbox->parent, irqstatus);
  
  	return (int)(enable & status & bit);
  }
  
  void omap_mbox_save_ctx(struct mbox_chan *chan)
  {
  	int i;
  	int nr_regs;
  	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
  
  	if (WARN_ON(!mbox))
  		return;
  
  	if (mbox->intr_type)
  		nr_regs = OMAP4_MBOX_NR_REGS;
  	else
  		nr_regs = MBOX_NR_REGS;
  	for (i = 0; i < nr_regs; i++) {
  		mbox->ctx[i] = mbox_read_reg(mbox->parent, i * sizeof(u32));
  
  		dev_dbg(mbox->dev, "%s: [%02x] %08x\n", __func__,
  			i, mbox->ctx[i]);
  	}
  }
  EXPORT_SYMBOL(omap_mbox_save_ctx);
  
  void omap_mbox_restore_ctx(struct mbox_chan *chan)
  {
  	int i;
  	int nr_regs;
  	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
  
  	if (WARN_ON(!mbox))
  		return;
  
  	if (mbox->intr_type)
  		nr_regs = OMAP4_MBOX_NR_REGS;
  	else
  		nr_regs = MBOX_NR_REGS;
  	for (i = 0; i < nr_regs; i++) {
  		mbox_write_reg(mbox->parent, mbox->ctx[i], i * sizeof(u32));
  		dev_dbg(mbox->dev, "%s: [%02x] %08x\n", __func__,
  			i, mbox->ctx[i]);
  	}
  }
  EXPORT_SYMBOL(omap_mbox_restore_ctx);
  
  static void _omap_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
  {
  	u32 l;
  	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
  				&mbox->tx_fifo : &mbox->rx_fifo;
  	u32 bit = fifo->intr_bit;
  	u32 irqenable = fifo->irqenable;
  
  	l = mbox_read_reg(mbox->parent, irqenable);
  	l |= bit;
  	mbox_write_reg(mbox->parent, l, irqenable);
  }
  
  static void _omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
  {
  	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
  				&mbox->tx_fifo : &mbox->rx_fifo;
  	u32 bit = fifo->intr_bit;
  	u32 irqdisable = fifo->irqdisable;
  
  	/*
  	 * Read and update the interrupt configuration register for pre-OMAP4.
  	 * OMAP4 and later SoCs have a dedicated interrupt disabling register.
  	 */
  	if (!mbox->intr_type)
  		bit = mbox_read_reg(mbox->parent, irqdisable) & ~bit;
  
  	mbox_write_reg(mbox->parent, bit, irqdisable);
  }
  
  void omap_mbox_enable_irq(struct mbox_chan *chan, omap_mbox_irq_t irq)
  {
  	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
  
  	if (WARN_ON(!mbox))
  		return;
  
  	_omap_mbox_enable_irq(mbox, irq);
  }
  EXPORT_SYMBOL(omap_mbox_enable_irq);
  
  void omap_mbox_disable_irq(struct mbox_chan *chan, omap_mbox_irq_t irq)
  {
  	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
  
  	if (WARN_ON(!mbox))
  		return;
  
  	_omap_mbox_disable_irq(mbox, irq);
  }
  EXPORT_SYMBOL(omap_mbox_disable_irq);
  
  /*
   * Message receiver(workqueue)
   */
  static void mbox_rx_work(struct work_struct *work)
  {
  	struct omap_mbox_queue *mq =
  			container_of(work, struct omap_mbox_queue, work);
  	mbox_msg_t msg;
  	int len;
  
  	while (kfifo_len(&mq->fifo) >= sizeof(msg)) {
  		len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
  		WARN_ON(len != sizeof(msg));
  
  		mbox_chan_received_data(mq->mbox->chan, (void *)msg);
  		spin_lock_irq(&mq->lock);
  		if (mq->full) {
  			mq->full = false;
  			_omap_mbox_enable_irq(mq->mbox, IRQ_RX);
  		}
  		spin_unlock_irq(&mq->lock);
  	}
  }
  
  /*
   * Mailbox interrupt handler
   */
  static void __mbox_tx_interrupt(struct omap_mbox *mbox)
  {
  	_omap_mbox_disable_irq(mbox, IRQ_TX);
  	ack_mbox_irq(mbox, IRQ_TX);
  	mbox_chan_txdone(mbox->chan, 0);
  }
  
  static void __mbox_rx_interrupt(struct omap_mbox *mbox)
  {
  	struct omap_mbox_queue *mq = mbox->rxq;
  	mbox_msg_t msg;
  	int len;
  
  	while (!mbox_fifo_empty(mbox)) {
  		if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
  			_omap_mbox_disable_irq(mbox, IRQ_RX);
  			mq->full = true;
  			goto nomem;
  		}
  
  		msg = mbox_fifo_read(mbox);
  
  		len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
  		WARN_ON(len != sizeof(msg));
  	}
  
  	/* no more messages in the fifo. clear IRQ source. */
  	ack_mbox_irq(mbox, IRQ_RX);
  nomem:
  	schedule_work(&mbox->rxq->work);
  }
  
  static irqreturn_t mbox_interrupt(int irq, void *p)
  {
  	struct omap_mbox *mbox = p;
  
  	if (is_mbox_irq(mbox, IRQ_TX))
  		__mbox_tx_interrupt(mbox);
  
  	if (is_mbox_irq(mbox, IRQ_RX))
  		__mbox_rx_interrupt(mbox);
  
  	return IRQ_HANDLED;
  }
  
  static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
  					void (*work)(struct work_struct *))
  {
  	struct omap_mbox_queue *mq;
  
  	if (!work)
  		return NULL;
  
  	mq = kzalloc(sizeof(struct omap_mbox_queue), GFP_KERNEL);
  	if (!mq)
  		return NULL;
  
  	spin_lock_init(&mq->lock);
  
  	if (kfifo_alloc(&mq->fifo, mbox_kfifo_size, GFP_KERNEL))
  		goto error;
  
  	INIT_WORK(&mq->work, work);
  	return mq;
  
  error:
  	kfree(mq);
  	return NULL;
  }
  
  static void mbox_queue_free(struct omap_mbox_queue *q)
  {
  	kfifo_free(&q->fifo);
  	kfree(q);
  }
  
  static int omap_mbox_startup(struct omap_mbox *mbox)
  {
  	int ret = 0;
  	struct omap_mbox_queue *mq;
  
  	mq = mbox_queue_alloc(mbox, mbox_rx_work);
  	if (!mq)
  		return -ENOMEM;
  	mbox->rxq = mq;
  	mq->mbox = mbox;
  
  	ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
  			  mbox->name, mbox);
  	if (unlikely(ret)) {
  		pr_err("failed to register mailbox interrupt:%d\n", ret);
  		goto fail_request_irq;
  	}
  
  	if (mbox->send_no_irq)
  		mbox->chan->txdone_method = TXDONE_BY_ACK;
  
  	_omap_mbox_enable_irq(mbox, IRQ_RX);
  
  	return 0;
  
  fail_request_irq:
  	mbox_queue_free(mbox->rxq);
  	return ret;
  }
  
  static void omap_mbox_fini(struct omap_mbox *mbox)
  {
  	_omap_mbox_disable_irq(mbox, IRQ_RX);
  	free_irq(mbox->irq, mbox);
  	flush_work(&mbox->rxq->work);
  	mbox_queue_free(mbox->rxq);
  }
  
  static struct omap_mbox *omap_mbox_device_find(struct omap_mbox_device *mdev,
  					       const char *mbox_name)
  {
  	struct omap_mbox *_mbox, *mbox = NULL;
  	struct omap_mbox **mboxes = mdev->mboxes;
  	int i;
  
  	if (!mboxes)
  		return NULL;
  
  	for (i = 0; (_mbox = mboxes[i]); i++) {
  		if (!strcmp(_mbox->name, mbox_name)) {
  			mbox = _mbox;
  			break;
  		}
  	}
  	return mbox;
  }
  
  struct mbox_chan *omap_mbox_request_channel(struct mbox_client *cl,
  					    const char *chan_name)
  {
  	struct device *dev = cl->dev;
  	struct omap_mbox *mbox = NULL;
  	struct omap_mbox_device *mdev;
  	struct mbox_chan *chan;
  	unsigned long flags;
  	int ret;
  
  	if (!dev)
  		return ERR_PTR(-ENODEV);
  
  	if (dev->of_node) {
  		pr_err("%s: please use mbox_request_channel(), this API is supported only for OMAP non-DT usage\n",
  		       __func__);
  		return ERR_PTR(-ENODEV);
  	}
  
  	mutex_lock(&omap_mbox_devices_lock);
  	list_for_each_entry(mdev, &omap_mbox_devices, elem) {
  		mbox = omap_mbox_device_find(mdev, chan_name);
  		if (mbox)
  			break;
  	}
  	mutex_unlock(&omap_mbox_devices_lock);
  
  	if (!mbox || !mbox->chan)
  		return ERR_PTR(-ENOENT);
  
  	chan = mbox->chan;
  	spin_lock_irqsave(&chan->lock, flags);
  	chan->msg_free = 0;
  	chan->msg_count = 0;
  	chan->active_req = NULL;
  	chan->cl = cl;
  	init_completion(&chan->tx_complete);
  	spin_unlock_irqrestore(&chan->lock, flags);
  
  	ret = chan->mbox->ops->startup(chan);
  	if (ret) {
  		pr_err("Unable to startup the chan (%d)\n", ret);
  		mbox_free_channel(chan);
  		chan = ERR_PTR(ret);
  	}
  
  	return chan;
  }
  EXPORT_SYMBOL(omap_mbox_request_channel);
  
  static struct class omap_mbox_class = { .name = "mbox", };
  
  static int omap_mbox_register(struct omap_mbox_device *mdev)
  {
  	int ret;
  	int i;
  	struct omap_mbox **mboxes;
  
  	if (!mdev || !mdev->mboxes)
  		return -EINVAL;
  
  	mboxes = mdev->mboxes;
  	for (i = 0; mboxes[i]; i++) {
  		struct omap_mbox *mbox = mboxes[i];
  		mbox->dev = device_create(&omap_mbox_class, mdev->dev,
  					0, mbox, "%s", mbox->name);
  		if (IS_ERR(mbox->dev)) {
  			ret = PTR_ERR(mbox->dev);
  			goto err_out;
  		}
  	}
  
  	mutex_lock(&omap_mbox_devices_lock);
  	list_add(&mdev->elem, &omap_mbox_devices);
  	mutex_unlock(&omap_mbox_devices_lock);
  
  	ret = mbox_controller_register(&mdev->controller);
  
  err_out:
  	if (ret) {
  		while (i--)
  			device_unregister(mboxes[i]->dev);
  	}
  	return ret;
  }
  
  static int omap_mbox_unregister(struct omap_mbox_device *mdev)
  {
  	int i;
  	struct omap_mbox **mboxes;
  
  	if (!mdev || !mdev->mboxes)
  		return -EINVAL;
  
  	mutex_lock(&omap_mbox_devices_lock);
  	list_del(&mdev->elem);
  	mutex_unlock(&omap_mbox_devices_lock);
  
  	mbox_controller_unregister(&mdev->controller);
  
  	mboxes = mdev->mboxes;
  	for (i = 0; mboxes[i]; i++)
  		device_unregister(mboxes[i]->dev);
  	return 0;
  }
  
  static int omap_mbox_chan_startup(struct mbox_chan *chan)
  {
  	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
  	struct omap_mbox_device *mdev = mbox->parent;
  	int ret = 0;
  
  	mutex_lock(&mdev->cfg_lock);
  	pm_runtime_get_sync(mdev->dev);
  	ret = omap_mbox_startup(mbox);
  	if (ret)
  		pm_runtime_put_sync(mdev->dev);
  	mutex_unlock(&mdev->cfg_lock);
  	return ret;
  }
  
  static void omap_mbox_chan_shutdown(struct mbox_chan *chan)
  {
  	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
  	struct omap_mbox_device *mdev = mbox->parent;
  
  	mutex_lock(&mdev->cfg_lock);
  	omap_mbox_fini(mbox);
  	pm_runtime_put_sync(mdev->dev);
  	mutex_unlock(&mdev->cfg_lock);
  }
  
  static int omap_mbox_chan_send_noirq(struct omap_mbox *mbox, void *data)
  {
  	int ret = -EBUSY;
  
  	if (!mbox_fifo_full(mbox)) {
  		_omap_mbox_enable_irq(mbox, IRQ_RX);
  		mbox_fifo_write(mbox, (mbox_msg_t)data);
  		ret = 0;
  		_omap_mbox_disable_irq(mbox, IRQ_RX);
  
  		/* we must read and ack the interrupt directly from here */
  		mbox_fifo_read(mbox);
  		ack_mbox_irq(mbox, IRQ_RX);
  	}
  
  	return ret;
  }
  
  static int omap_mbox_chan_send(struct omap_mbox *mbox, void *data)
  {
  	int ret = -EBUSY;
  
  	if (!mbox_fifo_full(mbox)) {
  		mbox_fifo_write(mbox, (mbox_msg_t)data);
  		ret = 0;
  	}
  
  	/* always enable the interrupt */
  	_omap_mbox_enable_irq(mbox, IRQ_TX);
  	return ret;
  }
  
  static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
  {
  	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
  	int ret;
  
  	if (!mbox)
  		return -EINVAL;
  
  	if (mbox->send_no_irq)
  		ret = omap_mbox_chan_send_noirq(mbox, data);
  	else
  		ret = omap_mbox_chan_send(mbox, data);
  
  	return ret;
  }
  
  static const struct mbox_chan_ops omap_mbox_chan_ops = {
  	.startup        = omap_mbox_chan_startup,
  	.send_data      = omap_mbox_chan_send_data,
  	.shutdown       = omap_mbox_chan_shutdown,
  };
  
  static const struct of_device_id omap_mailbox_of_match[] = {
  	{
  		.compatible	= "ti,omap2-mailbox",
  		.data		= (void *)MBOX_INTR_CFG_TYPE1,
  	},
  	{
  		.compatible	= "ti,omap3-mailbox",
  		.data		= (void *)MBOX_INTR_CFG_TYPE1,
  	},
  	{
  		.compatible	= "ti,omap4-mailbox",
  		.data		= (void *)MBOX_INTR_CFG_TYPE2,
  	},
  	{
  		/* end */
  	},
  };
  MODULE_DEVICE_TABLE(of, omap_mailbox_of_match);
  
  static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,
  					    const struct of_phandle_args *sp)
  {
  	phandle phandle = sp->args[0];
  	struct device_node *node;
  	struct omap_mbox_device *mdev;
  	struct omap_mbox *mbox;
  
  	mdev = container_of(controller, struct omap_mbox_device, controller);
  	if (WARN_ON(!mdev))
  		return ERR_PTR(-EINVAL);
  
  	node = of_find_node_by_phandle(phandle);
  	if (!node) {
  		pr_err("%s: could not find node phandle 0x%x\n",
  		       __func__, phandle);
  		return ERR_PTR(-ENODEV);
  	}
  
  	mbox = omap_mbox_device_find(mdev, node->name);
  	of_node_put(node);
  	return mbox ? mbox->chan : ERR_PTR(-ENOENT);
  }
  
  static int omap_mbox_probe(struct platform_device *pdev)
  {
  	struct resource *mem;
  	int ret;
  	struct mbox_chan *chnls;
  	struct omap_mbox **list, *mbox, *mboxblk;
  	struct omap_mbox_pdata *pdata = pdev->dev.platform_data;
  	struct omap_mbox_dev_info *info = NULL;
  	struct omap_mbox_fifo_info *finfo, *finfoblk;
  	struct omap_mbox_device *mdev;
  	struct omap_mbox_fifo *fifo;
  	struct device_node *node = pdev->dev.of_node;
  	struct device_node *child;
  	const struct of_device_id *match;
  	u32 intr_type, info_count;
  	u32 num_users, num_fifos;
  	u32 tmp[3];
  	u32 l;
  	int i;
  
  	if (!node && (!pdata || !pdata->info_cnt || !pdata->info)) {
  		pr_err("%s: platform not supported\n", __func__);
  		return -ENODEV;
  	}
  
  	if (node) {
  		match = of_match_device(omap_mailbox_of_match, &pdev->dev);
  		if (!match)
  			return -ENODEV;
  		intr_type = (u32)match->data;
  
  		if (of_property_read_u32(node, "ti,mbox-num-users",
  					 &num_users))
  			return -ENODEV;
  
  		if (of_property_read_u32(node, "ti,mbox-num-fifos",
  					 &num_fifos))
  			return -ENODEV;
  
  		info_count = of_get_available_child_count(node);
  		if (!info_count) {
  			dev_err(&pdev->dev, "no available mbox devices found\n");
  			return -ENODEV;
  		}
  	} else { /* non-DT device creation */
  		info_count = pdata->info_cnt;
  		info = pdata->info;
  		intr_type = pdata->intr_type;
  		num_users = pdata->num_users;
  		num_fifos = pdata->num_fifos;
  	}
  
  	finfoblk = devm_kzalloc(&pdev->dev, info_count * sizeof(*finfoblk),
  				GFP_KERNEL);
  	if (!finfoblk)
  		return -ENOMEM;
  
  	finfo = finfoblk;
  	child = NULL;
  	for (i = 0; i < info_count; i++, finfo++) {
  		if (node) {
  			child = of_get_next_available_child(node, child);
  			ret = of_property_read_u32_array(child, "ti,mbox-tx",
  							 tmp, ARRAY_SIZE(tmp));
  			if (ret)
  				return ret;
  			finfo->tx_id = tmp[0];
  			finfo->tx_irq = tmp[1];
  			finfo->tx_usr = tmp[2];
  
  			ret = of_property_read_u32_array(child, "ti,mbox-rx",
  							 tmp, ARRAY_SIZE(tmp));
  			if (ret)
  				return ret;
  			finfo->rx_id = tmp[0];
  			finfo->rx_irq = tmp[1];
  			finfo->rx_usr = tmp[2];
  
  			finfo->name = child->name;
  
  			if (of_find_property(child, "ti,mbox-send-noirq", NULL))
  				finfo->send_no_irq = true;
  		} else {
  			finfo->tx_id = info->tx_id;
  			finfo->rx_id = info->rx_id;
  			finfo->tx_usr = info->usr_id;
  			finfo->tx_irq = info->irq_id;
  			finfo->rx_usr = info->usr_id;
  			finfo->rx_irq = info->irq_id;
  			finfo->name = info->name;
  			info++;
  		}
  		if (finfo->tx_id >= num_fifos || finfo->rx_id >= num_fifos ||
  		    finfo->tx_usr >= num_users || finfo->rx_usr >= num_users)
  			return -EINVAL;
  	}
  
  	mdev = devm_kzalloc(&pdev->dev, sizeof(*mdev), GFP_KERNEL);
  	if (!mdev)
  		return -ENOMEM;
  
  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	mdev->mbox_base = devm_ioremap_resource(&pdev->dev, mem);
  	if (IS_ERR(mdev->mbox_base))
  		return PTR_ERR(mdev->mbox_base);
  
  	/* allocate one extra for marking end of list */
  	list = devm_kzalloc(&pdev->dev, (info_count + 1) * sizeof(*list),
  			    GFP_KERNEL);
  	if (!list)
  		return -ENOMEM;
  
  	chnls = devm_kzalloc(&pdev->dev, (info_count + 1) * sizeof(*chnls),
  			     GFP_KERNEL);
  	if (!chnls)
  		return -ENOMEM;
  
  	mboxblk = devm_kzalloc(&pdev->dev, info_count * sizeof(*mbox),
  			       GFP_KERNEL);
  	if (!mboxblk)
  		return -ENOMEM;
  
  	mbox = mboxblk;
  	finfo = finfoblk;
  	for (i = 0; i < info_count; i++, finfo++) {
  		fifo = &mbox->tx_fifo;
  		fifo->msg = MAILBOX_MESSAGE(finfo->tx_id);
  		fifo->fifo_stat = MAILBOX_FIFOSTATUS(finfo->tx_id);
  		fifo->intr_bit = MAILBOX_IRQ_NOTFULL(finfo->tx_id);
  		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, finfo->tx_usr);
  		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, finfo->tx_usr);
  		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, finfo->tx_usr);
  
  		fifo = &mbox->rx_fifo;
  		fifo->msg = MAILBOX_MESSAGE(finfo->rx_id);
  		fifo->msg_stat =  MAILBOX_MSGSTATUS(finfo->rx_id);
  		fifo->intr_bit = MAILBOX_IRQ_NEWMSG(finfo->rx_id);
  		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, finfo->rx_usr);
  		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, finfo->rx_usr);
  		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, finfo->rx_usr);
  
  		mbox->send_no_irq = finfo->send_no_irq;
  		mbox->intr_type = intr_type;
  
  		mbox->parent = mdev;
  		mbox->name = finfo->name;
  		mbox->irq = platform_get_irq(pdev, finfo->tx_irq);
  		if (mbox->irq < 0)
  			return mbox->irq;
  		mbox->chan = &chnls[i];
  		chnls[i].con_priv = mbox;
  		list[i] = mbox++;
  	}
  
  	mutex_init(&mdev->cfg_lock);
  	mdev->dev = &pdev->dev;
  	mdev->num_users = num_users;
  	mdev->num_fifos = num_fifos;
  	mdev->mboxes = list;
  
  	/* OMAP does not have a Tx-Done IRQ, but rather a Tx-Ready IRQ */
  	mdev->controller.txdone_irq = true;
  	mdev->controller.dev = mdev->dev;
  	mdev->controller.ops = &omap_mbox_chan_ops;
  	mdev->controller.chans = chnls;
  	mdev->controller.num_chans = info_count;
  	mdev->controller.of_xlate = omap_mbox_of_xlate;
  	ret = omap_mbox_register(mdev);
  	if (ret)
  		return ret;
  
  	platform_set_drvdata(pdev, mdev);
  	pm_runtime_enable(mdev->dev);
  
  	ret = pm_runtime_get_sync(mdev->dev);
  	if (ret < 0) {
  		pm_runtime_put_noidle(mdev->dev);
  		goto unregister;
  	}
  
  	/*
  	 * just print the raw revision register, the format is not
  	 * uniform across all SoCs
  	 */
  	l = mbox_read_reg(mdev, MAILBOX_REVISION);
  	dev_info(mdev->dev, "omap mailbox rev 0x%x\n", l);
  
  	ret = pm_runtime_put_sync(mdev->dev);
  	if (ret < 0)
  		goto unregister;
  
  	devm_kfree(&pdev->dev, finfoblk);
  	return 0;
  
  unregister:
  	pm_runtime_disable(mdev->dev);
  	omap_mbox_unregister(mdev);
  	return ret;
  }
  
  static int omap_mbox_remove(struct platform_device *pdev)
  {
  	struct omap_mbox_device *mdev = platform_get_drvdata(pdev);
  
  	pm_runtime_disable(mdev->dev);
  	omap_mbox_unregister(mdev);
  
  	return 0;
  }
  
  static struct platform_driver omap_mbox_driver = {
  	.probe	= omap_mbox_probe,
  	.remove	= omap_mbox_remove,
  	.driver	= {
  		.name = "omap-mailbox",
  		.of_match_table = of_match_ptr(omap_mailbox_of_match),
  	},
  };
  
  static int __init omap_mbox_init(void)
  {
  	int err;
  
  	err = class_register(&omap_mbox_class);
  	if (err)
  		return err;
  
  	/* kfifo size sanity check: alignment and minimal size */
  	mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
  	mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size,
  							sizeof(mbox_msg_t));
  
  	return platform_driver_register(&omap_mbox_driver);
  }
  subsys_initcall(omap_mbox_init);
  
  static void __exit omap_mbox_exit(void)
  {
  	platform_driver_unregister(&omap_mbox_driver);
  	class_unregister(&omap_mbox_class);
  }
  module_exit(omap_mbox_exit);
  
  MODULE_LICENSE("GPL v2");
  MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
  MODULE_AUTHOR("Toshihiro Kobayashi");
  MODULE_AUTHOR("Hiroshi DOYU");
  