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

ARM MHU Mailbox Driver

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

The ARM's 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.

The last channel is specified to be a 'Secure' resource, hence can't be

used by Linux running NS.

Mailbox Device Node:

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

Required properties:

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

- compatible:		Shall be "arm,mhu" & "arm,primecell"

- 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 3 links of MHU.

Example:

--------

	mhu: mailbox@2b1f0000 {

		#mbox-cells = <1>;

		compatible = "arm,mhu", "arm,primecell";

		reg = <0 0x2b1f0000 0x1000>;

		interrupts = <0 36 4>, /* LP-NonSecure */

			     <0 35 4>, /* HP-NonSecure */

			     <0 37 4>; /* Secure */

		clocks = <&clock 0 2 1>;

		clock-names = "apb_pclk";

	};

	mhu_client: scb@2e000000 {

		compatible = "fujitsu,mb86s70-scb-1.0";

		reg = <0 0x2e000000 0x4000>;

		mboxes = <&mhu 1>; /* HP-NonSecure */

	};

	  signals. Say Y if your platform supports hardware mailboxes.

if MAILBOX

config ARM_MHU

	tristate "ARM MHU Mailbox"

	depends on ARM_AMBA

	help

	  Say Y here if you want to build the ARM MHU controller driver.

	  The controller has 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_MAILBOX)		+= mailbox.o

obj-$(CONFIG_ARM_MHU)	+= arm_mhu.o

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

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

/*

 * 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/amba/bus.h>

#include <linux/mailbox_controller.h>

#define INTR_STAT_OFS	0x0

#define INTR_SET_OFS	0x8

#define INTR_CLR_OFS	0x10

#define MHU_LP_OFFSET	0x0

#define MHU_HP_OFFSET	0x20

#define MHU_SEC_OFFSET	0x200

#define TX_REG_OFFSET	0x100

#define MHU_CHANS	3

struct mhu_link {

	unsigned irq;

	void __iomem *tx_reg;

	void __iomem *rx_reg;

};

struct arm_mhu {

	void __iomem *base;

	struct mhu_link mlink[MHU_CHANS];

	struct mbox_chan chan[MHU_CHANS];

	struct mbox_controller mbox;

};

static irqreturn_t mhu_rx_interrupt(int irq, void *p)

{

	struct mbox_chan *chan = p;

	struct 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 mhu_last_tx_done(struct mbox_chan *chan)

{

	struct mhu_link *mlink = chan->con_priv;

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

	return (val == 0);

}

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

{

	struct mhu_link *mlink = chan->con_priv;

	u32 *arg = data;

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

	return 0;

}

static int mhu_startup(struct mbox_chan *chan)

{

	struct 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, mhu_rx_interrupt,

			  IRQF_SHARED, "mhu_link", chan);

	if (ret) {

		dev_err(chan->mbox->dev,

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

		return ret;

	}

	return 0;

}

static void mhu_shutdown(struct mbox_chan *chan)

{

	struct mhu_link *mlink = chan->con_priv;

	free_irq(mlink->irq, chan);

}

static struct mbox_chan_ops mhu_ops = {

	.send_data = mhu_send_data,

	.startup = mhu_startup,

	.shutdown = mhu_shutdown,

	.last_tx_done = mhu_last_tx_done,

};

static int mhu_probe(struct amba_device *adev, const struct amba_id *id)

{

	int i, err;

	struct arm_mhu *mhu;

	struct device *dev = &adev->dev;

	int mhu_reg[MHU_CHANS] = {MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET};

	/* Allocate memory for device */

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

	if (!mhu)

		return -ENOMEM;

	mhu->base = devm_ioremap_resource(dev, &adev->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 = adev->irq[i];

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

	mhu->mbox.txdone_irq = false;

	mhu->mbox.txdone_poll = true;

	mhu->mbox.txpoll_period = 10;

	amba_set_drvdata(adev, mhu);

	err = mbox_controller_register(&mhu->mbox);

	if (err) {

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

		return err;

	}

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

	return 0;

}

static int mhu_remove(struct amba_device *adev)

{

	struct arm_mhu *mhu = amba_get_drvdata(adev);

	mbox_controller_unregister(&mhu->mbox);

	return 0;

}

static struct amba_id mhu_ids[] = {

	{

		.id	= 0x1bb098,

		.mask	= 0xffffff,

	},

	{ 0, 0 },

};

MODULE_DEVICE_TABLE(amba, mhu_ids);

static struct amba_driver arm_mhu_driver = {

	.drv = {

		.name	= "mhu",

	},

	.id_table	= mhu_ids,

	.probe		= mhu_probe,

	.remove		= mhu_remove,

};

module_amba_driver(arm_mhu_driver);

MODULE_LICENSE("GPL v2");

MODULE_DESCRIPTION("ARM MHU Driver");

MODULE_AUTHOR("Jassi Brar <jassisinghbrar@gmail.com>");

 *  shared memory regions as defined in the PCC table entries. The PCC

 *  specification supports a Doorbell mechanism for the PCC clients

 *  to notify the platform about new data. This Doorbell information

 *  is also specified in each PCC table entry. See pcc_send_data()

 *  and pcc_tx_done() for basic mode of operation.

 *  is also specified in each PCC table entry.

 *

 *  Typical high level flow of operation is:

 *

 *  PCC Reads:

 *  * Client tries to acquire a channel lock.

 *  * After it is acquired it writes READ cmd in communication region cmd

 *		address.

 *  * Client issues mbox_send_message() which rings the PCC doorbell

 *		for its PCC channel.

 *  * If command completes, then client has control over channel and

 *		it can proceed with its reads.

 *  * Client releases lock.

 *

 *  PCC Writes:

 *  * Client tries to acquire channel lock.

 *  * Client writes to its communication region after it acquires a

 *		channel lock.

 *  * Client writes WRITE cmd in communication region cmd address.

 *  * Client issues mbox_send_message() which rings the PCC doorbell

 *		for its PCC channel.

 *  * If command completes, then writes have succeded and it can release

 *		the channel lock.

 *

 *  There is a Nominal latency defined for each channel which indicates

 *  how long to wait until a command completes. If command is not complete

 *  the client needs to retry or assume failure.

 *

 *	For more details about PCC, please see the ACPI specification from

 *  http://www.uefi.org/ACPIv5.1 Section 14.

#include "mailbox.h"

#define MAX_PCC_SUBSPACES	256

#define PCCS_SS_SIG_MAGIC	0x50434300

#define PCC_CMD_COMPLETE	0x1

static struct mbox_chan *pcc_mbox_channels;

	return pcc_chan;

}

/**

 * get_subspace_id - Given a Mailbox channel, find out the

 *		PCC subspace id.

 * @chan: Pointer to Mailbox Channel from which we want

 *		the index.

 * Return: Errno if not found, else positive index number.

 */

static int get_subspace_id(struct mbox_chan *chan)

{

	unsigned int id = chan - pcc_mbox_channels;

	if (id < 0 || id > pcc_mbox_ctrl.num_chans)

		return -ENOENT;

	return id;

}

/**

 * pcc_mbox_request_channel - PCC clients call this function to

 *		request a pointer to their PCC subspace, from which they

	chan = get_pcc_channel(subspace_id);

	if (!chan || chan->cl) {

		dev_err(dev, "%s: PCC mailbox not free\n", __func__);

		dev_err(dev, "Channel not found for idx: %d\n", subspace_id);

		return ERR_PTR(-EBUSY);

	}

EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);

/**

 * pcc_tx_done - Callback from Mailbox controller code to

 *		check if PCC message transmission completed.

 * @chan: Pointer to Mailbox channel on which previous

 *		transmission occurred.

 *

 * Return: TRUE if succeeded.

 */

static bool pcc_tx_done(struct mbox_chan *chan)

{

	struct acpi_pcct_hw_reduced *pcct_ss = chan->con_priv;

	struct acpi_pcct_shared_memory *generic_comm_base =

		(struct acpi_pcct_shared_memory *) pcct_ss->base_address;

	u16 cmd_delay = pcct_ss->latency;

	unsigned int retries = 0;

	/* Try a few times while waiting for platform to consume */

	while (!(readw_relaxed(&generic_comm_base->status)

		    & PCC_CMD_COMPLETE)) {

		if (retries++ < 5)

			udelay(cmd_delay);

		else {

			/*

			 * If the remote is dead, this will cause the Mbox

			 * controller to timeout after mbox client.tx_tout

			 * msecs.

			 */

			pr_err("PCC platform did not respond.\n");

			return false;

		}

	}

	return true;

}

/**

 * pcc_send_data - Called from Mailbox Controller code to finally

 *	transmit data over channel.

 * pcc_send_data - Called from Mailbox Controller code. Used

 *		here only to ring the channel doorbell. The PCC client

 *		specific read/write is done in the client driver in

 *		order to maintain atomicity over PCC channel once

 *		OS has control over it. See above for flow of operations.

 * @chan: Pointer to Mailbox channel over which to send data.

 * @data: Actual data to be written over channel.

 * @data: Client specific data written over channel. Used here

 *		only for debug after PCC transaction completes.

 *

 * Return: Err if something failed else 0 for success.

 */

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

{

	struct acpi_pcct_hw_reduced *pcct_ss = chan->con_priv;

	struct acpi_pcct_shared_memory *generic_comm_base =

		(struct acpi_pcct_shared_memory *) pcct_ss->base_address;

	struct acpi_generic_address doorbell;

	u64 doorbell_preserve;

	u64 doorbell_val;

	u64 doorbell_write;

	u16 cmd = *(u16 *) data;

	u16 ss_idx = -1;

	ss_idx = get_subspace_id(chan);

	if (ss_idx < 0) {

		pr_err("Invalid Subspace ID from PCC client\n");

		return -EINVAL;

	}

	doorbell = pcct_ss->doorbell_register;

	doorbell_preserve = pcct_ss->preserve_mask;

	doorbell_write = pcct_ss->write_mask;

	/* Write to the shared comm region. */

	writew(cmd, &generic_comm_base->command);

	/* Write Subspace MAGIC value so platform can identify destination. */

	writel((PCCS_SS_SIG_MAGIC | ss_idx), &generic_comm_base->signature);

	/* Flip CMD COMPLETE bit */

	writew(0, &generic_comm_base->status);

	/* Sync notification from OSPM to Platform. */

	/* Sync notification from OS to Platform. */

	acpi_read(&doorbell_val, &doorbell);

	acpi_write((doorbell_val & doorbell_preserve) | doorbell_write,

			&doorbell);

static struct mbox_chan_ops pcc_chan_ops = {

	.send_data = pcc_send_data,

	.last_tx_done = pcc_tx_done,

};

/**

	pcc_mbox_ctrl.chans = pcc_mbox_channels;

	pcc_mbox_ctrl.ops = &pcc_chan_ops;

	pcc_mbox_ctrl.txdone_poll = true;

	pcc_mbox_ctrl.txpoll_period = 10;

	pcc_mbox_ctrl.dev = &pdev->dev;

	pr_info("Registering PCC driver as Mailbox controller\n");