[linux-2.6-block.git] / drivers / mailbox / mailbox-sti.c

/*
 * STi Mailbox
 *
 * Copyright (C) 2015 ST Microelectronics
 *
 * Author: Lee Jones <lee.jones@linaro.org> for ST Microelectronics
 *
 * Based on the original driver written by;
 *   Alexandre Torgue, Olivier Lebreton and Loic Pallardy
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/err.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/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include "mailbox.h"

#define STI_MBOX_INST_MAX	4      /* RAM saving: Max supported instances */
#define STI_MBOX_CHAN_MAX	20     /* RAM saving: Max supported channels  */

#define STI_IRQ_VAL_OFFSET	0x04   /* Read interrupt status	              */
#define STI_IRQ_SET_OFFSET	0x24   /* Generate a Tx channel interrupt     */
#define STI_IRQ_CLR_OFFSET	0x44   /* Clear pending Rx interrupts	      */
#define STI_ENA_VAL_OFFSET	0x64   /* Read enable status		      */
#define STI_ENA_SET_OFFSET	0x84   /* Enable a channel		      */
#define STI_ENA_CLR_OFFSET	0xa4   /* Disable a channel		      */

#define MBOX_BASE(mdev, inst)   ((mdev)->base + ((inst) * 4))

/**
 * STi Mailbox device data
 *
 * An IP Mailbox is currently composed of 4 instances
 * Each instance is currently composed of 32 channels
 * This means that we have 128 channels per Mailbox
 * A channel an be used for TX or RX
 *
 * @dev:	Device to which it is attached
 * @mbox:	Representation of a communication channel controller
 * @base:	Base address of the register mapping region
 * @name:	Name of the mailbox
 * @enabled:	Local copy of enabled channels
 * @lock:	Mutex protecting enabled status
 */
struct sti_mbox_device {
	struct device		*dev;
	struct mbox_controller	*mbox;
	void __iomem		*base;
	const char		*name;
	u32			enabled[STI_MBOX_INST_MAX];
	spinlock_t		lock;
};

/**
 * STi Mailbox platform specific configuration
 *
 * @num_inst:	Maximum number of instances in one HW Mailbox
 * @num_chan:	Maximum number of channel per instance
 */
struct sti_mbox_pdata {
	unsigned int		num_inst;
	unsigned int		num_chan;
};

/**
 * STi Mailbox allocated channel information
 *
 * @mdev:	Pointer to parent Mailbox device
 * @instance:	Instance number channel resides in
 * @channel:	Channel number pertaining to this container
 */
struct sti_channel {
	struct sti_mbox_device	*mdev;
	unsigned int		instance;
	unsigned int		channel;
};

static inline bool sti_mbox_channel_is_enabled(struct mbox_chan *chan)
{
	struct sti_channel *chan_info = chan->con_priv;
	struct sti_mbox_device *mdev = chan_info->mdev;
	unsigned int instance = chan_info->instance;
	unsigned int channel = chan_info->channel;

	return mdev->enabled[instance] & BIT(channel);
}

static inline
struct mbox_chan *sti_mbox_to_channel(struct mbox_controller *mbox,
				      unsigned int instance,
				      unsigned int channel)
{
	struct sti_channel *chan_info;
	int i;

	for (i = 0; i < mbox->num_chans; i++) {
		chan_info = mbox->chans[i].con_priv;
		if (chan_info &&
		    chan_info->instance == instance &&
		    chan_info->channel == channel)
			return &mbox->chans[i];
	}

	dev_err(mbox->dev,
		"Channel not registered: instance: %d channel: %d\n",
		instance, channel);

	return NULL;
}

static void sti_mbox_enable_channel(struct mbox_chan *chan)
{
	struct sti_channel *chan_info = chan->con_priv;
	struct sti_mbox_device *mdev = chan_info->mdev;
	unsigned int instance = chan_info->instance;
	unsigned int channel = chan_info->channel;
	unsigned long flags;
	void __iomem *base = MBOX_BASE(mdev, instance);

	spin_lock_irqsave(&mdev->lock, flags);
	mdev->enabled[instance] |= BIT(channel);
	writel_relaxed(BIT(channel), base + STI_ENA_SET_OFFSET);
	spin_unlock_irqrestore(&mdev->lock, flags);
}

static void sti_mbox_disable_channel(struct mbox_chan *chan)
{
	struct sti_channel *chan_info = chan->con_priv;
	struct sti_mbox_device *mdev = chan_info->mdev;
	unsigned int instance = chan_info->instance;
	unsigned int channel = chan_info->channel;
	unsigned long flags;
	void __iomem *base = MBOX_BASE(mdev, instance);

	spin_lock_irqsave(&mdev->lock, flags);
	mdev->enabled[instance] &= ~BIT(channel);
	writel_relaxed(BIT(channel), base + STI_ENA_CLR_OFFSET);
	spin_unlock_irqrestore(&mdev->lock, flags);
}

static void sti_mbox_clear_irq(struct mbox_chan *chan)
{
	struct sti_channel *chan_info = chan->con_priv;
	struct sti_mbox_device *mdev = chan_info->mdev;
	unsigned int instance = chan_info->instance;
	unsigned int channel = chan_info->channel;
	void __iomem *base = MBOX_BASE(mdev, instance);

	writel_relaxed(BIT(channel), base + STI_IRQ_CLR_OFFSET);
}

static struct mbox_chan *sti_mbox_irq_to_channel(struct sti_mbox_device *mdev,
						 unsigned int instance)
{
	struct mbox_controller *mbox = mdev->mbox;
	struct mbox_chan *chan = NULL;
	unsigned int channel;
	unsigned long bits;
	void __iomem *base = MBOX_BASE(mdev, instance);

	bits = readl_relaxed(base + STI_IRQ_VAL_OFFSET);
	if (!bits)
		/* No IRQs fired in specified instance */
		return NULL;

	/* An IRQ has fired, find the associated channel */
	for (channel = 0; bits; channel++) {
		if (!test_and_clear_bit(channel, &bits))
			continue;

		chan = sti_mbox_to_channel(mbox, instance, channel);
		if (chan) {
			dev_dbg(mbox->dev,
				"IRQ fired on instance: %d channel: %d\n",
				instance, channel);
			break;
		}
	}

	return chan;
}

static irqreturn_t sti_mbox_thread_handler(int irq, void *data)
{
	struct sti_mbox_device *mdev = data;
	struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
	struct mbox_chan *chan;
	unsigned int instance;

	for (instance = 0; instance < pdata->num_inst; instance++) {
keep_looking:
		chan = sti_mbox_irq_to_channel(mdev, instance);
		if (!chan)
			continue;

		mbox_chan_received_data(chan, NULL);
		sti_mbox_clear_irq(chan);
		sti_mbox_enable_channel(chan);
		goto keep_looking;
	}

	return IRQ_HANDLED;
}

static irqreturn_t sti_mbox_irq_handler(int irq, void *data)
{
	struct sti_mbox_device *mdev = data;
	struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
	struct sti_channel *chan_info;
	struct mbox_chan *chan;
	unsigned int instance;
	int ret = IRQ_NONE;

	for (instance = 0; instance < pdata->num_inst; instance++) {
		chan = sti_mbox_irq_to_channel(mdev, instance);
		if (!chan)
			continue;
		chan_info = chan->con_priv;

		if (!sti_mbox_channel_is_enabled(chan)) {
			dev_warn(mdev->dev,
				 "Unexpected IRQ: %s\n"
				 "  instance: %d: channel: %d [enabled: %x]\n",
				 mdev->name, chan_info->instance,
				 chan_info->channel, mdev->enabled[instance]);

			/* Only handle IRQ if no other valid IRQs were found */
			if (ret == IRQ_NONE)
				ret = IRQ_HANDLED;
			continue;
		}

		sti_mbox_disable_channel(chan);
		ret = IRQ_WAKE_THREAD;
	}

	if (ret == IRQ_NONE)
		dev_err(mdev->dev, "Spurious IRQ - was a channel requested?\n");

	return ret;
}

static bool sti_mbox_tx_is_ready(struct mbox_chan *chan)
{
	struct sti_channel *chan_info = chan->con_priv;
	struct sti_mbox_device *mdev = chan_info->mdev;
	unsigned int instance = chan_info->instance;
	unsigned int channel = chan_info->channel;
	void __iomem *base = MBOX_BASE(mdev, instance);

	if (!(readl_relaxed(base + STI_ENA_VAL_OFFSET) & BIT(channel))) {
		dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d disabled\n",
			mdev->name, instance, channel);
		return false;
	}

	if (readl_relaxed(base + STI_IRQ_VAL_OFFSET) & BIT(channel)) {
		dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d not ready\n",
			mdev->name, instance, channel);
		return false;
	}

	return true;
}

static int sti_mbox_send_data(struct mbox_chan *chan, void *data)
{
	struct sti_channel *chan_info = chan->con_priv;
	struct sti_mbox_device *mdev = chan_info->mdev;
	unsigned int instance = chan_info->instance;
	unsigned int channel = chan_info->channel;
	void __iomem *base = MBOX_BASE(mdev, instance);

	/* Send event to co-processor */
	writel_relaxed(BIT(channel), base + STI_IRQ_SET_OFFSET);

	dev_dbg(mdev->dev,
		"Sent via Mailbox %s: instance: %d channel: %d\n",
		mdev->name, instance, channel);

	return 0;
}

static int sti_mbox_startup_chan(struct mbox_chan *chan)
{
	sti_mbox_clear_irq(chan);
	sti_mbox_enable_channel(chan);

	return 0;
}

static void sti_mbox_shutdown_chan(struct mbox_chan *chan)
{
	struct sti_channel *chan_info = chan->con_priv;
	struct mbox_controller *mbox = chan_info->mdev->mbox;
	int i;

	for (i = 0; i < mbox->num_chans; i++)
		if (chan == &mbox->chans[i])
			break;

	if (mbox->num_chans == i) {
		dev_warn(mbox->dev, "Request to free non-existent channel\n");
		return;
	}

	/* Reset channel */
	sti_mbox_disable_channel(chan);
	sti_mbox_clear_irq(chan);
	chan->con_priv = NULL;
}

static struct mbox_chan *sti_mbox_xlate(struct mbox_controller *mbox,
					const struct of_phandle_args *spec)
{
	struct sti_mbox_device *mdev = dev_get_drvdata(mbox->dev);
	struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
	struct sti_channel *chan_info;
	struct mbox_chan *chan = NULL;
	unsigned int instance  = spec->args[0];
	unsigned int channel   = spec->args[1];
	int i;

	/* Bounds checking */
	if (instance >= pdata->num_inst || channel  >= pdata->num_chan) {
		dev_err(mbox->dev,
			"Invalid channel requested instance: %d channel: %d\n",
			instance, channel);
		return ERR_PTR(-EINVAL);
	}

	for (i = 0; i < mbox->num_chans; i++) {
		chan_info = mbox->chans[i].con_priv;

		/* Is requested channel free? */
		if (chan_info &&
		    mbox->dev == chan_info->mdev->dev &&
		    instance == chan_info->instance &&
		    channel == chan_info->channel) {

			dev_err(mbox->dev, "Channel in use\n");
			return ERR_PTR(-EBUSY);
		}

		/*
		 * Find the first free slot, then continue checking
		 * to see if requested channel is in use
		 */
		if (!chan && !chan_info)
			chan = &mbox->chans[i];
	}

	if (!chan) {
		dev_err(mbox->dev, "No free channels left\n");
		return ERR_PTR(-EBUSY);
	}

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

	chan_info->mdev		= mdev;
	chan_info->instance	= instance;
	chan_info->channel	= channel;

	chan->con_priv = chan_info;

	dev_info(mbox->dev,
		 "Mbox: %s: Created channel: instance: %d channel: %d\n",
		 mdev->name, instance, channel);

	return chan;
}

static const struct mbox_chan_ops sti_mbox_ops = {
	.startup	= sti_mbox_startup_chan,
	.shutdown	= sti_mbox_shutdown_chan,
	.send_data	= sti_mbox_send_data,
	.last_tx_done	= sti_mbox_tx_is_ready,
};

static const struct sti_mbox_pdata mbox_stih407_pdata = {
	.num_inst	= 4,
	.num_chan	= 32,
};

static const struct of_device_id sti_mailbox_match[] = {
	{
		.compatible = "st,stih407-mailbox",
		.data = (void *)&mbox_stih407_pdata
	},
	{ }
};

static int sti_mbox_probe(struct platform_device *pdev)
{
	const struct of_device_id *match;
	struct mbox_controller *mbox;
	struct sti_mbox_device *mdev;
	struct device_node *np = pdev->dev.of_node;
	struct mbox_chan *chans;
	struct resource *res;
	int irq;
	int ret;

	match = of_match_device(sti_mailbox_match, &pdev->dev);
	if (!match) {
		dev_err(&pdev->dev, "No configuration found\n");
		return -ENODEV;
	}
	pdev->dev.platform_data = (struct sti_mbox_pdata *) match->data;

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

	platform_set_drvdata(pdev, mdev);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	mdev->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(mdev->base))
		return PTR_ERR(mdev->base);

	ret = of_property_read_string(np, "mbox-name", &mdev->name);
	if (ret)
		mdev->name = np->full_name;

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

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

	mdev->dev		= &pdev->dev;
	mdev->mbox		= mbox;

	spin_lock_init(&mdev->lock);

	/* STi Mailbox does not have a Tx-Done or Tx-Ready IRQ */
	mbox->txdone_irq	= false;
	mbox->txdone_poll	= true;
	mbox->txpoll_period	= 100;
	mbox->ops		= &sti_mbox_ops;
	mbox->dev		= mdev->dev;
	mbox->of_xlate		= sti_mbox_xlate;
	mbox->chans		= chans;
	mbox->num_chans		= STI_MBOX_CHAN_MAX;

	ret = mbox_controller_register(mbox);
	if (ret)
		return ret;

	/* It's okay for Tx Mailboxes to not supply IRQs */
	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_info(&pdev->dev,
			 "%s: Registered Tx only Mailbox\n", mdev->name);
		return 0;
	}

	ret = devm_request_threaded_irq(&pdev->dev, irq,
					sti_mbox_irq_handler,
					sti_mbox_thread_handler,
					IRQF_ONESHOT, mdev->name, mdev);
	if (ret) {
		dev_err(&pdev->dev, "Can't claim IRQ %d\n", irq);
		mbox_controller_unregister(mbox);
		return -EINVAL;
	}

	dev_info(&pdev->dev, "%s: Registered Tx/Rx Mailbox\n", mdev->name);

	return 0;
}

static int sti_mbox_remove(struct platform_device *pdev)
{
	struct sti_mbox_device *mdev = platform_get_drvdata(pdev);

	mbox_controller_unregister(mdev->mbox);

	return 0;
}

static struct platform_driver sti_mbox_driver = {
	.probe = sti_mbox_probe,
	.remove = sti_mbox_remove,
	.driver = {
		.name = "sti-mailbox",
		.of_match_table = sti_mailbox_match,
	},
};
module_platform_driver(sti_mbox_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("STMicroelectronics Mailbox Controller");
MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
MODULE_ALIAS("platform:mailbox-sti");
Commit	Line	Data
9ef4546c LJ	1	/*
	2	* STi Mailbox
	3	*
	4	* Copyright (C) 2015 ST Microelectronics
	5	*
	6	* Author: Lee Jones <lee.jones@linaro.org> for ST Microelectronics
	7	*
	8	* Based on the original driver written by;
	9	* Alexandre Torgue, Olivier Lebreton and Loic Pallardy
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; either version 2 of the License, or
	14	* (at your option) any later version.
	15	*/
	16
	17	#include <linux/err.h>
	18	#include <linux/interrupt.h>
	19	#include <linux/io.h>
	20	#include <linux/kernel.h>
	21	#include <linux/mailbox_controller.h>
	22	#include <linux/module.h>
	23	#include <linux/of.h>
	24	#include <linux/of_device.h>
	25	#include <linux/platform_device.h>
	26	#include <linux/slab.h>
	27
	28	#include "mailbox.h"
	29
	30	#define STI_MBOX_INST_MAX 4 /* RAM saving: Max supported instances */
	31	#define STI_MBOX_CHAN_MAX 20 /* RAM saving: Max supported channels */
	32
	33	#define STI_IRQ_VAL_OFFSET 0x04 /* Read interrupt status */
	34	#define STI_IRQ_SET_OFFSET 0x24 /* Generate a Tx channel interrupt */
	35	#define STI_IRQ_CLR_OFFSET 0x44 /* Clear pending Rx interrupts */
	36	#define STI_ENA_VAL_OFFSET 0x64 /* Read enable status */
	37	#define STI_ENA_SET_OFFSET 0x84 /* Enable a channel */
	38	#define STI_ENA_CLR_OFFSET 0xa4 /* Disable a channel */
	39
	40	#define MBOX_BASE(mdev, inst) ((mdev)->base + ((inst) * 4))
	41
	42	/**
	43	* STi Mailbox device data
	44	*
	45	* An IP Mailbox is currently composed of 4 instances
	46	* Each instance is currently composed of 32 channels
	47	* This means that we have 128 channels per Mailbox
	48	* A channel an be used for TX or RX
	49	*
	50	* @dev: Device to which it is attached
	51	* @mbox: Representation of a communication channel controller
	52	* @base: Base address of the register mapping region
	53	* @name: Name of the mailbox
	54	* @enabled: Local copy of enabled channels
	55	* @lock: Mutex protecting enabled status
	56	*/
	57	struct sti_mbox_device {
	58	struct device *dev;
	59	struct mbox_controller *mbox;
	60	void __iomem *base;
	61	const char *name;
	62	u32 enabled[STI_MBOX_INST_MAX];
	63	spinlock_t lock;
	64	};
65
66	/**
6c03663f	67	* STi Mailbox platform specific configuration
9ef4546c LJ	68	*
	69	* @num_inst: Maximum number of instances in one HW Mailbox
	70	* @num_chan: Maximum number of channel per instance
	71	*/
	72	struct sti_mbox_pdata {
	73	unsigned int num_inst;
	74	unsigned int num_chan;
	75	};
	76
	77	/**
	78	* STi Mailbox allocated channel information
	79	*
	80	* @mdev: Pointer to parent Mailbox device
	81	* @instance: Instance number channel resides in
	82	* @channel: Channel number pertaining to this container
	83	*/
	84	struct sti_channel {
	85	struct sti_mbox_device *mdev;
	86	unsigned int instance;
	87	unsigned int channel;
	88	};
	89
	90	static inline bool sti_mbox_channel_is_enabled(struct mbox_chan *chan)
	91	{
	92	struct sti_channel *chan_info = chan->con_priv;
	93	struct sti_mbox_device *mdev = chan_info->mdev;
	94	unsigned int instance = chan_info->instance;
	95	unsigned int channel = chan_info->channel;
	96
	97	return mdev->enabled[instance] & BIT(channel);
	98	}
	99
	100	static inline
	101	struct mbox_chan sti_mbox_to_channel(struct mbox_controller mbox,
	102	unsigned int instance,
	103	unsigned int channel)
	104	{
	105	struct sti_channel *chan_info;
	106	int i;
	107
	108	for (i = 0; i < mbox->num_chans; i++) {
	109	chan_info = mbox->chans[i].con_priv;
	110	if (chan_info &&
	111	chan_info->instance == instance &&
	112	chan_info->channel == channel)
	113	return &mbox->chans[i];
	114	}
	115
	116	dev_err(mbox->dev,
	117	"Channel not registered: instance: %d channel: %d\n",
	118	instance, channel);
	119
	120	return NULL;
	121	}
	122
	123	static void sti_mbox_enable_channel(struct mbox_chan *chan)
	124	{
	125	struct sti_channel *chan_info = chan->con_priv;
	126	struct sti_mbox_device *mdev = chan_info->mdev;
	127	unsigned int instance = chan_info->instance;
	128	unsigned int channel = chan_info->channel;
	129	unsigned long flags;
	130	void __iomem *base = MBOX_BASE(mdev, instance);
	131
132	spin_lock_irqsave(&mdev->lock, flags);
133	mdev->enabled[instance] \|= BIT(channel);
134	writel_relaxed(BIT(channel), base + STI_ENA_SET_OFFSET);
135	spin_unlock_irqrestore(&mdev->lock, flags);
136	}
137
138	static void sti_mbox_disable_channel(struct mbox_chan *chan)
139	{
140	struct sti_channel *chan_info = chan->con_priv;
141	struct sti_mbox_device *mdev = chan_info->mdev;
142	unsigned int instance = chan_info->instance;
143	unsigned int channel = chan_info->channel;
144	unsigned long flags;
145	void __iomem *base = MBOX_BASE(mdev, instance);
146
147	spin_lock_irqsave(&mdev->lock, flags);
148	mdev->enabled[instance] &= ~BIT(channel);
149	writel_relaxed(BIT(channel), base + STI_ENA_CLR_OFFSET);
150	spin_unlock_irqrestore(&mdev->lock, flags);
151	}
152
153	static void sti_mbox_clear_irq(struct mbox_chan *chan)
154	{
155	struct sti_channel *chan_info = chan->con_priv;
156	struct sti_mbox_device *mdev = chan_info->mdev;
157	unsigned int instance = chan_info->instance;
158	unsigned int channel = chan_info->channel;
159	void __iomem *base = MBOX_BASE(mdev, instance);
160
161	writel_relaxed(BIT(channel), base + STI_IRQ_CLR_OFFSET);
162	}
163
164	static struct mbox_chan sti_mbox_irq_to_channel(struct sti_mbox_device mdev,
165	unsigned int instance)
166	{
167	struct mbox_controller *mbox = mdev->mbox;
168	struct mbox_chan *chan = NULL;
169	unsigned int channel;
170	unsigned long bits;
171	void __iomem *base = MBOX_BASE(mdev, instance);
172
173	bits = readl_relaxed(base + STI_IRQ_VAL_OFFSET);
174	if (!bits)
175	/* No IRQs fired in specified instance */
176	return NULL;
177
178	/* An IRQ has fired, find the associated channel */
179	for (channel = 0; bits; channel++) {
180	if (!test_and_clear_bit(channel, &bits))
181	continue;
182
183	chan = sti_mbox_to_channel(mbox, instance, channel);
184	if (chan) {
185	dev_dbg(mbox->dev,
186	"IRQ fired on instance: %d channel: %d\n",
187	instance, channel);
188	break;
189	}
190	}
191
192	return chan;
193	}
194
195	static irqreturn_t sti_mbox_thread_handler(int irq, void *data)
196	{
197	struct sti_mbox_device *mdev = data;
198	struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
199	struct mbox_chan *chan;
200	unsigned int instance;
201
202	for (instance = 0; instance < pdata->num_inst; instance++) {
203	keep_looking:
204	chan = sti_mbox_irq_to_channel(mdev, instance);
205	if (!chan)
206	continue;
207
208	mbox_chan_received_data(chan, NULL);
209	sti_mbox_clear_irq(chan);
210	sti_mbox_enable_channel(chan);
211	goto keep_looking;
212	}
213
214	return IRQ_HANDLED;
215	}
216
217	static irqreturn_t sti_mbox_irq_handler(int irq, void *data)
218	{
219	struct sti_mbox_device *mdev = data;
220	struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
221	struct sti_channel *chan_info;
222	struct mbox_chan *chan;
223	unsigned int instance;
224	int ret = IRQ_NONE;
225
226	for (instance = 0; instance < pdata->num_inst; instance++) {
227	chan = sti_mbox_irq_to_channel(mdev, instance);
228	if (!chan)
229	continue;
230	chan_info = chan->con_priv;
231
232	if (!sti_mbox_channel_is_enabled(chan)) {
233	dev_warn(mdev->dev,
234	"Unexpected IRQ: %s\n"
235	" instance: %d: channel: %d [enabled: %x]\n",
236	mdev->name, chan_info->instance,
237	chan_info->channel, mdev->enabled[instance]);
238
239	/* Only handle IRQ if no other valid IRQs were found */
240	if (ret == IRQ_NONE)
241	ret = IRQ_HANDLED;
242	continue;
243	}
244
245	sti_mbox_disable_channel(chan);
246	ret = IRQ_WAKE_THREAD;
247	}
248
249	if (ret == IRQ_NONE)
250	dev_err(mdev->dev, "Spurious IRQ - was a channel requested?\n");
251
252	return ret;
253	}
254
255	static bool sti_mbox_tx_is_ready(struct mbox_chan *chan)
256	{
257	struct sti_channel *chan_info = chan->con_priv;
258	struct sti_mbox_device *mdev = chan_info->mdev;
259	unsigned int instance = chan_info->instance;
260	unsigned int channel = chan_info->channel;
261	void __iomem *base = MBOX_BASE(mdev, instance);
262
263	if (!(readl_relaxed(base + STI_ENA_VAL_OFFSET) & BIT(channel))) {
264	dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d disabled\n",
265	mdev->name, instance, channel);
266	return false;
267	}
268
269	if (readl_relaxed(base + STI_IRQ_VAL_OFFSET) & BIT(channel)) {
270	dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d not ready\n",
271	mdev->name, instance, channel);
272	return false;
273	}
274
275	return true;
276	}
277
278	static int sti_mbox_send_data(struct mbox_chan chan, void data)
279	{
280	struct sti_channel *chan_info = chan->con_priv;
281	struct sti_mbox_device *mdev = chan_info->mdev;
282	unsigned int instance = chan_info->instance;
283	unsigned int channel = chan_info->channel;
284	void __iomem *base = MBOX_BASE(mdev, instance);
285
286	/* Send event to co-processor */
287	writel_relaxed(BIT(channel), base + STI_IRQ_SET_OFFSET);
288
289	dev_dbg(mdev->dev,
290	"Sent via Mailbox %s: instance: %d channel: %d\n",
291	mdev->name, instance, channel);
292
293	return 0;
294	}
295
296	static int sti_mbox_startup_chan(struct mbox_chan *chan)
297	{
298	sti_mbox_clear_irq(chan);
299	sti_mbox_enable_channel(chan);
300
301	return 0;
302	}
303
304	static void sti_mbox_shutdown_chan(struct mbox_chan *chan)
305	{
306	struct sti_channel *chan_info = chan->con_priv;
307	struct mbox_controller *mbox = chan_info->mdev->mbox;
308	int i;
309
310	for (i = 0; i < mbox->num_chans; i++)
311	if (chan == &mbox->chans[i])
312	break;
313
314	if (mbox->num_chans == i) {
315	dev_warn(mbox->dev, "Request to free non-existent channel\n");
316	return;
317	}
318
319	/* Reset channel */
320	sti_mbox_disable_channel(chan);
321	sti_mbox_clear_irq(chan);
322	chan->con_priv = NULL;
323	}
324
325	static struct mbox_chan sti_mbox_xlate(struct mbox_controller mbox,
326	const struct of_phandle_args *spec)
327	{
328	struct sti_mbox_device *mdev = dev_get_drvdata(mbox->dev);
329	struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
330	struct sti_channel *chan_info;
331	struct mbox_chan *chan = NULL;
332	unsigned int instance = spec->args[0];
333	unsigned int channel = spec->args[1];
334	int i;
335
336	/* Bounds checking */
337	if (instance >= pdata->num_inst \|\| channel >= pdata->num_chan) {
338	dev_err(mbox->dev,
339	"Invalid channel requested instance: %d channel: %d\n",
340	instance, channel);
341	return ERR_PTR(-EINVAL);
342	}
343
344	for (i = 0; i < mbox->num_chans; i++) {
345	chan_info = mbox->chans[i].con_priv;
346
347	/* Is requested channel free? */
348	if (chan_info &&
349	mbox->dev == chan_info->mdev->dev &&
350	instance == chan_info->instance &&
351	channel == chan_info->channel) {
352
353	dev_err(mbox->dev, "Channel in use\n");
354	return ERR_PTR(-EBUSY);
355	}
356
357	/*
358	* Find the first free slot, then continue checking
359	* to see if requested channel is in use
360	*/
361	if (!chan && !chan_info)
362	chan = &mbox->chans[i];
363	}
364
365	if (!chan) {
366	dev_err(mbox->dev, "No free channels left\n");
367	return ERR_PTR(-EBUSY);
368	}
369
370	chan_info = devm_kzalloc(mbox->dev, sizeof(*chan_info), GFP_KERNEL);
371	if (!chan_info)
372	return ERR_PTR(-ENOMEM);
373
374	chan_info->mdev = mdev;
375	chan_info->instance = instance;
376	chan_info->channel = channel;
377
378	chan->con_priv = chan_info;
379
380	dev_info(mbox->dev,
381	"Mbox: %s: Created channel: instance: %d channel: %d\n",
382	mdev->name, instance, channel);
383
384	return chan;
385	}
386
bfbcfa77	387	static const struct mbox_chan_ops sti_mbox_ops = {
9ef4546c LJ	388	.startup = sti_mbox_startup_chan,
	389	.shutdown = sti_mbox_shutdown_chan,
	390	.send_data = sti_mbox_send_data,
	391	.last_tx_done = sti_mbox_tx_is_ready,
	392	};
	393
	394	static const struct sti_mbox_pdata mbox_stih407_pdata = {
	395	.num_inst = 4,
	396	.num_chan = 32,
	397	};
	398
	399	static const struct of_device_id sti_mailbox_match[] = {
	400	{
	401	.compatible = "st,stih407-mailbox",
	402	.data = (void *)&mbox_stih407_pdata
	403	},
	404	{ }
	405	};
	406
	407	static int sti_mbox_probe(struct platform_device *pdev)
	408	{
	409	const struct of_device_id *match;
	410	struct mbox_controller *mbox;
	411	struct sti_mbox_device *mdev;
	412	struct device_node *np = pdev->dev.of_node;
	413	struct mbox_chan *chans;
	414	struct resource *res;
	415	int irq;
	416	int ret;
	417
	418	match = of_match_device(sti_mailbox_match, &pdev->dev);
	419	if (!match) {
	420	dev_err(&pdev->dev, "No configuration found\n");
	421	return -ENODEV;
	422	}
	423	pdev->dev.platform_data = (struct sti_mbox_pdata *) match->data;
	424
	425	mdev = devm_kzalloc(&pdev->dev, sizeof(*mdev), GFP_KERNEL);
	426	if (!mdev)
	427	return -ENOMEM;
	428
	429	platform_set_drvdata(pdev, mdev);
	430
	431	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	432	mdev->base = devm_ioremap_resource(&pdev->dev, res);
c430cf37 AKC	433	if (IS_ERR(mdev->base))
c430cf37 AKC	434	return PTR_ERR(mdev->base);
9ef4546c LJ	435
	436	ret = of_property_read_string(np, "mbox-name", &mdev->name);
	437	if (ret)
	438	mdev->name = np->full_name;
	439
	440	mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
	441	if (!mbox)
	442	return -ENOMEM;
	443
	444	chans = devm_kzalloc(&pdev->dev,
	445	sizeof(chans) STI_MBOX_CHAN_MAX, GFP_KERNEL);
	446	if (!chans)
	447	return -ENOMEM;
	448
	449	mdev->dev = &pdev->dev;
	450	mdev->mbox = mbox;
	451
	452	spin_lock_init(&mdev->lock);
	453
	454	/* STi Mailbox does not have a Tx-Done or Tx-Ready IRQ */
	455	mbox->txdone_irq = false;
	456	mbox->txdone_poll = true;
	457	mbox->txpoll_period = 100;
	458	mbox->ops = &sti_mbox_ops;
	459	mbox->dev = mdev->dev;
	460	mbox->of_xlate = sti_mbox_xlate;
	461	mbox->chans = chans;
	462	mbox->num_chans = STI_MBOX_CHAN_MAX;
	463
	464	ret = mbox_controller_register(mbox);
	465	if (ret)
	466	return ret;
	467
	468	/* It's okay for Tx Mailboxes to not supply IRQs */
	469	irq = platform_get_irq(pdev, 0);
	470	if (irq < 0) {
	471	dev_info(&pdev->dev,
	472	"%s: Registered Tx only Mailbox\n", mdev->name);
	473	return 0;
	474	}
	475
	476	ret = devm_request_threaded_irq(&pdev->dev, irq,
	477	sti_mbox_irq_handler,
	478	sti_mbox_thread_handler,
	479	IRQF_ONESHOT, mdev->name, mdev);
	480	if (ret) {
	481	dev_err(&pdev->dev, "Can't claim IRQ %d\n", irq);
	482	mbox_controller_unregister(mbox);
	483	return -EINVAL;
	484	}
	485
	486	dev_info(&pdev->dev, "%s: Registered Tx/Rx Mailbox\n", mdev->name);
	487
	488	return 0;
	489	}
	490
	491	static int sti_mbox_remove(struct platform_device *pdev)
	492	{
	493	struct sti_mbox_device *mdev = platform_get_drvdata(pdev);
	494
	495	mbox_controller_unregister(mdev->mbox);
	496
	497	return 0;
	498	}
499
500	static struct platform_driver sti_mbox_driver = {
501	.probe = sti_mbox_probe,
502	.remove = sti_mbox_remove,
503	.driver = {
504	.name = "sti-mailbox",
505	.of_match_table = sti_mailbox_match,
506	},
507	};
508	module_platform_driver(sti_mbox_driver);
509
510	MODULE_LICENSE("GPL");
511	MODULE_DESCRIPTION("STMicroelectronics Mailbox Controller");
512	MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
513	MODULE_ALIAS("platform:mailbox-sti");