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Commit 9ef4546c authored by Lee Jones's avatar Lee Jones Committed by Jassi Brar
Browse files

mailbox: Add support for ST's Mailbox IP 



ST's platforms currently support a maximum of 5 Mailboxes, one for
each of the supported co-processors situated on the platform.  Each
Mailbox is divided up into 4 instances which consist of 32 channels.
Messages are passed between the application and co-processors using
shared memory areas.  It is the Client's responsibility to manage
these areas.

Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Signed-off-by: default avatarJassi Brar <jaswinder.singh@linaro.org>
parent b5f67376

drivers/mailbox/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -71,4 +71,11 @@ config BCM2835_MBOX 
	  the services of the Videocore. Say Y here if you want to use the

	  BCM2835 Mailbox.



config STI_MBOX

	tristate "STI Mailbox framework support"

	depends on ARCH_STI && OF

	help

	  Mailbox implementation for STMicroelectonics family chips with

	  hardware for interprocessor communication.



endif

drivers/mailbox/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -13,3 +13,5 @@ obj-$(CONFIG_PCC) += pcc.o 
obj-$(CONFIG_ALTERA_MBOX)	+= mailbox-altera.o



obj-$(CONFIG_BCM2835_MBOX)	+= bcm2835-mailbox.o



obj-$(CONFIG_STI_MBOX)		+= mailbox-sti.o

drivers/mailbox/mailbox-sti.c

0 → 100644
+513 −0
Original line number Diff line number Diff line 
/*

 * 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 specfic 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 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 (!mdev->base)

		return -ENOMEM;



	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");