Merge branch 'mailbox-for-next' of git://git.linaro.org/landing-teams/working/fujitsu/integration

Amlogic Meson MHU Mailbox Driver

================================

The Amlogic's Meson SoCs Message-Handling-Unit (MHU) is a mailbox controller

that has 3 independent channels/links to communicate with remote processor(s).

MHU links are hardwired on a platform. A link raises interrupt for any

received data. However, there is no specified way of knowing if the sent

data has been read by the remote. This driver assumes the sender polls

STAT register and the remote clears it after having read the data.

Mailbox Device Node:

====================

Required properties:

--------------------

- compatible:		Shall be "amlogic,meson-gxbb-mhu"

- reg:			Contains the mailbox register address range (base

			address and length)

- #mbox-cells		Shall be 1 - the index of the channel needed.

- interrupts:		Contains the interrupt information corresponding to

			each of the 2 links of MHU.

Example:

--------

	mailbox: mailbox@c883c404 {

		#mbox-cells = <1>;

		compatible = "amlogic,meson-gxbb-mhu";

		reg = <0 0xc883c404 0 0x4c>;

		interrupts = <0 208 IRQ_TYPE_EDGE_RISING>,

			     <0 209 IRQ_TYPE_EDGE_RISING>,

			     <0 210 IRQ_TYPE_EDGE_RISING>;

		#mbox-cells = <1>;

	};

	  The controller has 3 mailbox channels, the last of which can be

	  used in Secure mode only.

config PLATFORM_MHU

	tristate "Platform MHU Mailbox"

	depends on OF

	depends on HAS_IOMEM

	help

	  Say Y here if you want to build a platform specific variant MHU

	  controller driver.

	  The controller has a maximum of 3 mailbox channels, the last of

	  which can be used in Secure mode only.

config PL320_MBOX

	bool "ARM PL320 Mailbox"

	depends on ARM_AMBA

obj-$(CONFIG_ARM_MHU)	+= arm_mhu.o

obj-$(CONFIG_PLATFORM_MHU)	+= platform_mhu.o

obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o

obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o

/*

 * Copyright (C) 2016 BayLibre SAS.

 * Author: Neil Armstrong <narmstrong@baylibre.com>

 * Synchronised with arm_mhu.c from :

 * Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.

 * Copyright (C) 2015 Linaro Ltd.

 * Author: Jassi Brar <jaswinder.singh@linaro.org>

 *

 * 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, version 2 of the License.

 *

 * 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.

 */

#include <linux/interrupt.h>

#include <linux/spinlock.h>

#include <linux/mutex.h>

#include <linux/delay.h>

#include <linux/slab.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/mailbox_controller.h>

#define INTR_SET_OFS	0x0

#define INTR_STAT_OFS	0x4

#define INTR_CLR_OFS	0x8

#define MHU_SEC_OFFSET	0x0

#define MHU_LP_OFFSET	0xc

#define MHU_HP_OFFSET	0x18

#define TX_REG_OFFSET	0x24

#define MHU_CHANS	3

struct platform_mhu_link {

	int irq;

	void __iomem *tx_reg;

	void __iomem *rx_reg;

};

struct platform_mhu {

	void __iomem *base;

	struct platform_mhu_link mlink[MHU_CHANS];

	struct mbox_chan chan[MHU_CHANS];

	struct mbox_controller mbox;

};

static irqreturn_t platform_mhu_rx_interrupt(int irq, void *p)

{

	struct mbox_chan *chan = p;

	struct platform_mhu_link *mlink = chan->con_priv;

	u32 val;

	val = readl_relaxed(mlink->rx_reg + INTR_STAT_OFS);

	if (!val)

		return IRQ_NONE;

	mbox_chan_received_data(chan, (void *)&val);

	writel_relaxed(val, mlink->rx_reg + INTR_CLR_OFS);

	return IRQ_HANDLED;

}

static bool platform_mhu_last_tx_done(struct mbox_chan *chan)

{

	struct platform_mhu_link *mlink = chan->con_priv;

	u32 val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);

	return (val == 0);

}

static int platform_mhu_send_data(struct mbox_chan *chan, void *data)

{

	struct platform_mhu_link *mlink = chan->con_priv;

	u32 *arg = data;

	writel_relaxed(*arg, mlink->tx_reg + INTR_SET_OFS);

	return 0;

}

static int platform_mhu_startup(struct mbox_chan *chan)

{

	struct platform_mhu_link *mlink = chan->con_priv;

	u32 val;

	int ret;

	val = readl_relaxed(mlink->tx_reg + INTR_STAT_OFS);

	writel_relaxed(val, mlink->tx_reg + INTR_CLR_OFS);

	ret = request_irq(mlink->irq, platform_mhu_rx_interrupt,

			  IRQF_SHARED, "platform_mhu_link", chan);

	if (ret) {

		dev_err(chan->mbox->dev,

			"Unable to acquire IRQ %d\n", mlink->irq);

		return ret;

	}

	return 0;

}

static void platform_mhu_shutdown(struct mbox_chan *chan)

{

	struct platform_mhu_link *mlink = chan->con_priv;

	free_irq(mlink->irq, chan);

}

static const struct mbox_chan_ops platform_mhu_ops = {

	.send_data = platform_mhu_send_data,

	.startup = platform_mhu_startup,

	.shutdown = platform_mhu_shutdown,

	.last_tx_done = platform_mhu_last_tx_done,

};

static int platform_mhu_probe(struct platform_device *pdev)

{

	int i, err;

	struct platform_mhu *mhu;

	struct device *dev = &pdev->dev;

	struct resource *res;

	int platform_mhu_reg[MHU_CHANS] = {

		MHU_SEC_OFFSET, MHU_LP_OFFSET, MHU_HP_OFFSET

	};

	/* Allocate memory for device */

	mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);

	if (!mhu)

		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	mhu->base = devm_ioremap_resource(dev, res);

	if (IS_ERR(mhu->base)) {

		dev_err(dev, "ioremap failed\n");

		return PTR_ERR(mhu->base);

	}

	for (i = 0; i < MHU_CHANS; i++) {

		mhu->chan[i].con_priv = &mhu->mlink[i];

		mhu->mlink[i].irq = platform_get_irq(pdev, i);

		if (mhu->mlink[i].irq < 0) {

			dev_err(dev, "failed to get irq%d\n", i);

			return mhu->mlink[i].irq;

		}

		mhu->mlink[i].rx_reg = mhu->base + platform_mhu_reg[i];

		mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;

	}

	mhu->mbox.dev = dev;

	mhu->mbox.chans = &mhu->chan[0];

	mhu->mbox.num_chans = MHU_CHANS;

	mhu->mbox.ops = &platform_mhu_ops;

	mhu->mbox.txdone_irq = false;

	mhu->mbox.txdone_poll = true;

	mhu->mbox.txpoll_period = 1;

	platform_set_drvdata(pdev, mhu);

	err = mbox_controller_register(&mhu->mbox);

	if (err) {

		dev_err(dev, "Failed to register mailboxes %d\n", err);

		return err;

	}

	dev_info(dev, "Platform MHU Mailbox registered\n");

	return 0;

}

static int platform_mhu_remove(struct platform_device *pdev)

{

	struct platform_mhu *mhu = platform_get_drvdata(pdev);

	mbox_controller_unregister(&mhu->mbox);

	return 0;

}

static const struct of_device_id platform_mhu_dt_ids[] = {

	{ .compatible = "amlogic,meson-gxbb-mhu", },

	{ /* sentinel */ },

};

MODULE_DEVICE_TABLE(of, platform_mhu_dt_ids);

static struct platform_driver platform_mhu_driver = {

	.probe	= platform_mhu_probe,

	.remove	= platform_mhu_remove,

	.driver = {

		.name = "platform-mhu",

		.of_match_table	= platform_mhu_dt_ids,

	},

};

module_platform_driver(platform_mhu_driver);

MODULE_LICENSE("GPL v2");

MODULE_ALIAS("platform:platform-mhu");

MODULE_DESCRIPTION("Platform MHU Driver");

MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");