These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

11 files changed, 1236 insertions, 31 deletions

diff --git a/kernel/drivers/mailbox/Kconfig b/kernel/drivers/mailbox/Kconfig
index 84b0a2d74..546d05f43 100644
--- a/kernel/drivers/mailbox/Kconfig
+++ b/kernel/drivers/mailbox/Kconfig
@@ -46,6 +46,7 @@ config OMAP_MBOX_KFIFO_SIZE
 config PCC
 	bool "Platform Communication Channel Driver"
 	depends on ACPI
+	default n
 	help
 	  ACPI 5.0+ spec defines a generic mode of communication
 	  between the OS and a platform such as the BMC. This medium
@@ -56,8 +57,32 @@ config PCC
 
 config ALTERA_MBOX
 	tristate "Altera Mailbox"
+	depends on HAS_IOMEM
 	help
 	  An implementation of the Altera Mailbox soft core. It is used
 	  to send message between processors. Say Y here if you want to use the
 	  Altera mailbox support.
+
+config BCM2835_MBOX
+	tristate "BCM2835 Mailbox"
+	depends on ARCH_BCM2835
+	help
+	  An implementation of the BCM2385 Mailbox.  It is used to invoke
+	  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.
+
+config MAILBOX_TEST
+	tristate "Mailbox Test Client"
+	depends on OF
+	help
+	  Test client to help with testing new Controller driver
+	  implementations.
+
 endif
diff --git a/kernel/drivers/mailbox/Makefile b/kernel/drivers/mailbox/Makefile
index b18201e97..92435ef11 100644
--- a/kernel/drivers/mailbox/Makefile
+++ b/kernel/drivers/mailbox/Makefile
@@ -2,6 +2,8 @@
 
 obj-$(CONFIG_MAILBOX)		+= mailbox.o
 
+obj-$(CONFIG_MAILBOX_TEST)	+= mailbox-test.o
+
 obj-$(CONFIG_ARM_MHU)	+= arm_mhu.o
 
 obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
@@ -11,3 +13,7 @@ obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
 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
diff --git a/kernel/drivers/mailbox/arm_mhu.c b/kernel/drivers/mailbox/arm_mhu.c
index ac693c635..99befa76e 100644
--- a/kernel/drivers/mailbox/arm_mhu.c
+++ b/kernel/drivers/mailbox/arm_mhu.c
@@ -96,7 +96,7 @@ static int mhu_startup(struct mbox_chan *chan)
 			  IRQF_SHARED, "mhu_link", chan);
 	if (ret) {
 		dev_err(chan->mbox->dev,
-			"Unable to aquire IRQ %d\n", mlink->irq);
+			"Unable to acquire IRQ %d\n", mlink->irq);
 		return ret;
 	}
 
@@ -110,7 +110,7 @@ static void mhu_shutdown(struct mbox_chan *chan)
 	free_irq(mlink->irq, chan);
 }
 
-static struct mbox_chan_ops mhu_ops = {
+static const struct mbox_chan_ops mhu_ops = {
 	.send_data = mhu_send_data,
 	.startup = mhu_startup,
 	.shutdown = mhu_shutdown,
@@ -148,7 +148,7 @@ static int mhu_probe(struct amba_device *adev, const struct amba_id *id)
 	mhu->mbox.ops = &mhu_ops;
 	mhu->mbox.txdone_irq = false;
 	mhu->mbox.txdone_poll = true;
-	mhu->mbox.txpoll_period = 10;
+	mhu->mbox.txpoll_period = 1;
 
 	amba_set_drvdata(adev, mhu);
 
diff --git a/kernel/drivers/mailbox/bcm2835-mailbox.c b/kernel/drivers/mailbox/bcm2835-mailbox.c
new file mode 100644
index 000000000..cfb4b4496
--- /dev/null
+++ b/kernel/drivers/mailbox/bcm2835-mailbox.c
@@ -0,0 +1,216 @@
+/*
+ *  Copyright (C) 2010,2015 Broadcom
+ *  Copyright (C) 2013-2014 Lubomir Rintel
+ *  Copyright (C) 2013 Craig McGeachie
+ *
+ * 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 device provides a mechanism for writing to the mailboxes,
+ * that are shared between the ARM and the VideoCore processor
+ *
+ * Parts of the driver are based on:
+ *  - arch/arm/mach-bcm2708/vcio.c file written by Gray Girling that was
+ *    obtained from branch "rpi-3.6.y" of git://github.com/raspberrypi/
+ *    linux.git
+ *  - drivers/mailbox/bcm2835-ipc.c by Lubomir Rintel at
+ *    https://github.com/hackerspace/rpi-linux/blob/lr-raspberry-pi/drivers/
+ *    mailbox/bcm2835-ipc.c
+ *  - documentation available on the following web site:
+ *    https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+/* Mailboxes */
+#define ARM_0_MAIL0	0x00
+#define ARM_0_MAIL1	0x20
+
+/*
+ * Mailbox registers. We basically only support mailbox 0 & 1. We
+ * deliver to the VC in mailbox 1, it delivers to us in mailbox 0. See
+ * BCM2835-ARM-Peripherals.pdf section 1.3 for an explanation about
+ * the placement of memory barriers.
+ */
+#define MAIL0_RD	(ARM_0_MAIL0 + 0x00)
+#define MAIL0_POL	(ARM_0_MAIL0 + 0x10)
+#define MAIL0_STA	(ARM_0_MAIL0 + 0x18)
+#define MAIL0_CNF	(ARM_0_MAIL0 + 0x1C)
+#define MAIL1_WRT	(ARM_0_MAIL1 + 0x00)
+#define MAIL1_STA	(ARM_0_MAIL1 + 0x18)
+
+/* Status register: FIFO state. */
+#define ARM_MS_FULL		BIT(31)
+#define ARM_MS_EMPTY		BIT(30)
+
+/* Configuration register: Enable interrupts. */
+#define ARM_MC_IHAVEDATAIRQEN	BIT(0)
+
+struct bcm2835_mbox {
+	void __iomem *regs;
+	spinlock_t lock;
+	struct mbox_controller controller;
+};
+
+static struct bcm2835_mbox *bcm2835_link_mbox(struct mbox_chan *link)
+{
+	return container_of(link->mbox, struct bcm2835_mbox, controller);
+}
+
+static irqreturn_t bcm2835_mbox_irq(int irq, void *dev_id)
+{
+	struct bcm2835_mbox *mbox = dev_id;
+	struct device *dev = mbox->controller.dev;
+	struct mbox_chan *link = &mbox->controller.chans[0];
+
+	while (!(readl(mbox->regs + MAIL0_STA) & ARM_MS_EMPTY)) {
+		u32 msg = readl(mbox->regs + MAIL0_RD);
+		dev_dbg(dev, "Reply 0x%08X\n", msg);
+		mbox_chan_received_data(link, &msg);
+	}
+	return IRQ_HANDLED;
+}
+
+static int bcm2835_send_data(struct mbox_chan *link, void *data)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+	u32 msg = *(u32 *)data;
+
+	spin_lock(&mbox->lock);
+	writel(msg, mbox->regs + MAIL1_WRT);
+	dev_dbg(mbox->controller.dev, "Request 0x%08X\n", msg);
+	spin_unlock(&mbox->lock);
+	return 0;
+}
+
+static int bcm2835_startup(struct mbox_chan *link)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+
+	/* Enable the interrupt on data reception */
+	writel(ARM_MC_IHAVEDATAIRQEN, mbox->regs + MAIL0_CNF);
+
+	return 0;
+}
+
+static void bcm2835_shutdown(struct mbox_chan *link)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+
+	writel(0, mbox->regs + MAIL0_CNF);
+}
+
+static bool bcm2835_last_tx_done(struct mbox_chan *link)
+{
+	struct bcm2835_mbox *mbox = bcm2835_link_mbox(link);
+	bool ret;
+
+	spin_lock(&mbox->lock);
+	ret = !(readl(mbox->regs + MAIL1_STA) & ARM_MS_FULL);
+	spin_unlock(&mbox->lock);
+	return ret;
+}
+
+static const struct mbox_chan_ops bcm2835_mbox_chan_ops = {
+	.send_data	= bcm2835_send_data,
+	.startup	= bcm2835_startup,
+	.shutdown	= bcm2835_shutdown,
+	.last_tx_done	= bcm2835_last_tx_done
+};
+
+static struct mbox_chan *bcm2835_mbox_index_xlate(struct mbox_controller *mbox,
+		    const struct of_phandle_args *sp)
+{
+	if (sp->args_count != 0)
+		return NULL;
+
+	return &mbox->chans[0];
+}
+
+static int bcm2835_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int ret = 0;
+	struct resource *iomem;
+	struct bcm2835_mbox *mbox;
+
+	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+	if (mbox == NULL)
+		return -ENOMEM;
+	spin_lock_init(&mbox->lock);
+
+	ret = devm_request_irq(dev, irq_of_parse_and_map(dev->of_node, 0),
+			       bcm2835_mbox_irq, 0, dev_name(dev), mbox);
+	if (ret) {
+		dev_err(dev, "Failed to register a mailbox IRQ handler: %d\n",
+			ret);
+		return -ENODEV;
+	}
+
+	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mbox->regs = devm_ioremap_resource(&pdev->dev, iomem);
+	if (IS_ERR(mbox->regs)) {
+		ret = PTR_ERR(mbox->regs);
+		dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret);
+		return ret;
+	}
+
+	mbox->controller.txdone_poll = true;
+	mbox->controller.txpoll_period = 5;
+	mbox->controller.ops = &bcm2835_mbox_chan_ops;
+	mbox->controller.of_xlate = &bcm2835_mbox_index_xlate;
+	mbox->controller.dev = dev;
+	mbox->controller.num_chans = 1;
+	mbox->controller.chans = devm_kzalloc(dev,
+		sizeof(*mbox->controller.chans), GFP_KERNEL);
+	if (!mbox->controller.chans)
+		return -ENOMEM;
+
+	ret = mbox_controller_register(&mbox->controller);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, mbox);
+	dev_info(dev, "mailbox enabled\n");
+
+	return ret;
+}
+
+static int bcm2835_mbox_remove(struct platform_device *pdev)
+{
+	struct bcm2835_mbox *mbox = platform_get_drvdata(pdev);
+	mbox_controller_unregister(&mbox->controller);
+	return 0;
+}
+
+static const struct of_device_id bcm2835_mbox_of_match[] = {
+	{ .compatible = "brcm,bcm2835-mbox", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_mbox_of_match);
+
+static struct platform_driver bcm2835_mbox_driver = {
+	.driver = {
+		.name = "bcm2835-mbox",
+		.of_match_table = bcm2835_mbox_of_match,
+	},
+	.probe		= bcm2835_mbox_probe,
+	.remove		= bcm2835_mbox_remove,
+};
+module_platform_driver(bcm2835_mbox_driver);
+
+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
+MODULE_DESCRIPTION("BCM2835 mailbox IPC driver");
+MODULE_LICENSE("GPL v2");
diff --git a/kernel/drivers/mailbox/mailbox-altera.c b/kernel/drivers/mailbox/mailbox-altera.c
index a26626567..bb682c926 100644
--- a/kernel/drivers/mailbox/mailbox-altera.c
+++ b/kernel/drivers/mailbox/mailbox-altera.c
@@ -285,7 +285,7 @@ static void altera_mbox_shutdown(struct mbox_chan *chan)
 	}
 }
 
-static struct mbox_chan_ops altera_mbox_ops = {
+static const struct mbox_chan_ops altera_mbox_ops = {
 	.send_data = altera_mbox_send_data,
 	.startup = altera_mbox_startup,
 	.shutdown = altera_mbox_shutdown,
diff --git a/kernel/drivers/mailbox/mailbox-sti.c b/kernel/drivers/mailbox/mailbox-sti.c
new file mode 100644
index 000000000..4835817c5
--- /dev/null
+++ b/kernel/drivers/mailbox/mailbox-sti.c
@@ -0,0 +1,513 @@
+/*
+ * 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 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");
diff --git a/kernel/drivers/mailbox/mailbox-test.c b/kernel/drivers/mailbox/mailbox-test.c
new file mode 100644
index 000000000..684ae17dc
--- /dev/null
+++ b/kernel/drivers/mailbox/mailbox-test.c
@@ -0,0 +1,361 @@
+/*
+ * Copyright (C) 2015 ST Microelectronics
+ *
+ * Author: Lee Jones <lee.jones@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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#define MBOX_MAX_SIG_LEN	8
+#define MBOX_MAX_MSG_LEN	128
+#define MBOX_BYTES_PER_LINE	16
+#define MBOX_HEXDUMP_LINE_LEN	((MBOX_BYTES_PER_LINE * 4) + 2)
+#define MBOX_HEXDUMP_MAX_LEN	(MBOX_HEXDUMP_LINE_LEN *		\
+				 (MBOX_MAX_MSG_LEN / MBOX_BYTES_PER_LINE))
+
+static struct dentry *root_debugfs_dir;
+
+struct mbox_test_device {
+	struct device		*dev;
+	void __iomem		*mmio;
+	struct mbox_chan	*tx_channel;
+	struct mbox_chan	*rx_channel;
+	char			*rx_buffer;
+	char			*signal;
+	char			*message;
+	spinlock_t		lock;
+};
+
+static ssize_t mbox_test_signal_write(struct file *filp,
+				       const char __user *userbuf,
+				       size_t count, loff_t *ppos)
+{
+	struct mbox_test_device *tdev = filp->private_data;
+	int ret;
+
+	if (!tdev->tx_channel) {
+		dev_err(tdev->dev, "Channel cannot do Tx\n");
+		return -EINVAL;
+	}
+
+	if (count > MBOX_MAX_SIG_LEN) {
+		dev_err(tdev->dev,
+			"Signal length %zd greater than max allowed %d\n",
+			count, MBOX_MAX_SIG_LEN);
+		return -EINVAL;
+	}
+
+	tdev->signal = kzalloc(MBOX_MAX_SIG_LEN, GFP_KERNEL);
+	if (!tdev->signal)
+		return -ENOMEM;
+
+	ret = copy_from_user(tdev->signal, userbuf, count);
+	if (ret) {
+		kfree(tdev->signal);
+		return -EFAULT;
+	}
+
+	return ret < 0 ? ret : count;
+}
+
+static const struct file_operations mbox_test_signal_ops = {
+	.write	= mbox_test_signal_write,
+	.open	= simple_open,
+	.llseek	= generic_file_llseek,
+};
+
+static ssize_t mbox_test_message_write(struct file *filp,
+				       const char __user *userbuf,
+				       size_t count, loff_t *ppos)
+{
+	struct mbox_test_device *tdev = filp->private_data;
+	void *data;
+	int ret;
+
+	if (!tdev->tx_channel) {
+		dev_err(tdev->dev, "Channel cannot do Tx\n");
+		return -EINVAL;
+	}
+
+	if (count > MBOX_MAX_MSG_LEN) {
+		dev_err(tdev->dev,
+			"Message length %zd greater than max allowed %d\n",
+			count, MBOX_MAX_MSG_LEN);
+		return -EINVAL;
+	}
+
+	tdev->message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL);
+	if (!tdev->message)
+		return -ENOMEM;
+
+	ret = copy_from_user(tdev->message, userbuf, count);
+	if (ret) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	/*
+	 * A separate signal is only of use if there is
+	 * MMIO to subsequently pass the message through
+	 */
+	if (tdev->mmio && tdev->signal) {
+		print_hex_dump(KERN_INFO, "Client: Sending: Signal: ", DUMP_PREFIX_ADDRESS,
+			       MBOX_BYTES_PER_LINE, 1, tdev->signal, MBOX_MAX_SIG_LEN, true);
+
+		data = tdev->signal;
+	} else
+		data = tdev->message;
+
+	print_hex_dump(KERN_INFO, "Client: Sending: Message: ", DUMP_PREFIX_ADDRESS,
+		       MBOX_BYTES_PER_LINE, 1, tdev->message, MBOX_MAX_MSG_LEN, true);
+
+	ret = mbox_send_message(tdev->tx_channel, data);
+	if (ret < 0)
+		dev_err(tdev->dev, "Failed to send message via mailbox\n");
+
+out:
+	kfree(tdev->signal);
+	kfree(tdev->message);
+
+	return ret < 0 ? ret : count;
+}
+
+static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf,
+				      size_t count, loff_t *ppos)
+{
+	struct mbox_test_device *tdev = filp->private_data;
+	unsigned long flags;
+	char *touser, *ptr;
+	int l = 0;
+	int ret;
+
+	touser = kzalloc(MBOX_HEXDUMP_MAX_LEN + 1, GFP_KERNEL);
+	if (!touser)
+		return -ENOMEM;
+
+	if (!tdev->rx_channel) {
+		ret = snprintf(touser, 20, "<NO RX CAPABILITY>\n");
+		ret = simple_read_from_buffer(userbuf, count, ppos,
+					      touser, ret);
+		goto out;
+	}
+
+	if (tdev->rx_buffer[0] == '\0') {
+		ret = snprintf(touser, 9, "<EMPTY>\n");
+		ret = simple_read_from_buffer(userbuf, count, ppos,
+					      touser, ret);
+		goto out;
+	}
+
+	spin_lock_irqsave(&tdev->lock, flags);
+
+	ptr = tdev->rx_buffer;
+	while (l < MBOX_HEXDUMP_MAX_LEN) {
+		hex_dump_to_buffer(ptr,
+				   MBOX_BYTES_PER_LINE,
+				   MBOX_BYTES_PER_LINE, 1, touser + l,
+				   MBOX_HEXDUMP_LINE_LEN, true);
+
+		ptr += MBOX_BYTES_PER_LINE;
+		l += MBOX_HEXDUMP_LINE_LEN;
+		*(touser + (l - 1)) = '\n';
+	}
+	*(touser + l) = '\0';
+
+	memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN);
+
+	spin_unlock_irqrestore(&tdev->lock, flags);
+
+	ret = simple_read_from_buffer(userbuf, count, ppos, touser, MBOX_HEXDUMP_MAX_LEN);
+out:
+	kfree(touser);
+	return ret;
+}
+
+static const struct file_operations mbox_test_message_ops = {
+	.write	= mbox_test_message_write,
+	.read	= mbox_test_message_read,
+	.open	= simple_open,
+	.llseek	= generic_file_llseek,
+};
+
+static int mbox_test_add_debugfs(struct platform_device *pdev,
+				 struct mbox_test_device *tdev)
+{
+	if (!debugfs_initialized())
+		return 0;
+
+	root_debugfs_dir = debugfs_create_dir("mailbox", NULL);
+	if (!root_debugfs_dir) {
+		dev_err(&pdev->dev, "Failed to create Mailbox debugfs\n");
+		return -EINVAL;
+	}
+
+	debugfs_create_file("message", 0600, root_debugfs_dir,
+			    tdev, &mbox_test_message_ops);
+
+	debugfs_create_file("signal", 0200, root_debugfs_dir,
+			    tdev, &mbox_test_signal_ops);
+
+	return 0;
+}
+
+static void mbox_test_receive_message(struct mbox_client *client, void *message)
+{
+	struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&tdev->lock, flags);
+	if (tdev->mmio) {
+		memcpy_fromio(tdev->rx_buffer, tdev->mmio, MBOX_MAX_MSG_LEN);
+		print_hex_dump(KERN_INFO, "Client: Received [MMIO]: ",
+			       DUMP_PREFIX_ADDRESS, MBOX_BYTES_PER_LINE, 1,
+			       tdev->rx_buffer, MBOX_MAX_MSG_LEN, true);
+	} else if (message) {
+		print_hex_dump(KERN_INFO, "Client: Received [API]: ",
+			       DUMP_PREFIX_ADDRESS, MBOX_BYTES_PER_LINE, 1,
+			       message, MBOX_MAX_MSG_LEN, true);
+		memcpy(tdev->rx_buffer, message, MBOX_MAX_MSG_LEN);
+	}
+	spin_unlock_irqrestore(&tdev->lock, flags);
+}
+
+static void mbox_test_prepare_message(struct mbox_client *client, void *message)
+{
+	struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
+
+	if (tdev->mmio) {
+		if (tdev->signal)
+			memcpy_toio(tdev->mmio, tdev->message, MBOX_MAX_MSG_LEN);
+		else
+			memcpy_toio(tdev->mmio, message, MBOX_MAX_MSG_LEN);
+	}
+}
+
+static void mbox_test_message_sent(struct mbox_client *client,
+				   void *message, int r)
+{
+	if (r)
+		dev_warn(client->dev,
+			 "Client: Message could not be sent: %d\n", r);
+	else
+		dev_info(client->dev,
+			 "Client: Message sent\n");
+}
+
+static struct mbox_chan *
+mbox_test_request_channel(struct platform_device *pdev, const char *name)
+{
+	struct mbox_client *client;
+	struct mbox_chan *channel;
+
+	client = devm_kzalloc(&pdev->dev, sizeof(*client), GFP_KERNEL);
+	if (!client)
+		return ERR_PTR(-ENOMEM);
+
+	client->dev		= &pdev->dev;
+	client->rx_callback	= mbox_test_receive_message;
+	client->tx_prepare	= mbox_test_prepare_message;
+	client->tx_done		= mbox_test_message_sent;
+	client->tx_block	= true;
+	client->knows_txdone	= false;
+	client->tx_tout		= 500;
+
+	channel = mbox_request_channel_byname(client, name);
+	if (IS_ERR(channel)) {
+		dev_warn(&pdev->dev, "Failed to request %s channel\n", name);
+		return NULL;
+	}
+
+	return channel;
+}
+
+static int mbox_test_probe(struct platform_device *pdev)
+{
+	struct mbox_test_device *tdev;
+	struct resource *res;
+	int ret;
+
+	tdev = devm_kzalloc(&pdev->dev, sizeof(*tdev), GFP_KERNEL);
+	if (!tdev)
+		return -ENOMEM;
+
+	/* It's okay for MMIO to be NULL */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	tdev->mmio = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(tdev->mmio))
+		tdev->mmio = NULL;
+
+	tdev->tx_channel = mbox_test_request_channel(pdev, "tx");
+	tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
+
+	if (!tdev->tx_channel && !tdev->rx_channel)
+		return -EPROBE_DEFER;
+
+	tdev->dev = &pdev->dev;
+	platform_set_drvdata(pdev, tdev);
+
+	spin_lock_init(&tdev->lock);
+
+	if (tdev->rx_channel) {
+		tdev->rx_buffer = devm_kzalloc(&pdev->dev,
+					       MBOX_MAX_MSG_LEN, GFP_KERNEL);
+		if (!tdev->rx_buffer)
+			return -ENOMEM;
+	}
+
+	ret = mbox_test_add_debugfs(pdev, tdev);
+	if (ret)
+		return ret;
+
+	dev_info(&pdev->dev, "Successfully registered\n");
+
+	return 0;
+}
+
+static int mbox_test_remove(struct platform_device *pdev)
+{
+	struct mbox_test_device *tdev = platform_get_drvdata(pdev);
+
+	debugfs_remove_recursive(root_debugfs_dir);
+
+	if (tdev->tx_channel)
+		mbox_free_channel(tdev->tx_channel);
+	if (tdev->rx_channel)
+		mbox_free_channel(tdev->rx_channel);
+
+	return 0;
+}
+
+static const struct of_device_id mbox_test_match[] = {
+	{ .compatible = "mailbox_test" },
+	{},
+};
+
+static struct platform_driver mbox_test_driver = {
+	.driver = {
+		.name = "mailbox_sti_test",
+		.of_match_table = mbox_test_match,
+	},
+	.probe  = mbox_test_probe,
+	.remove = mbox_test_remove,
+};
+module_platform_driver(mbox_test_driver);
+
+MODULE_DESCRIPTION("Generic Mailbox Testing Facility");
+MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
+MODULE_LICENSE("GPL v2");
diff --git a/kernel/drivers/mailbox/mailbox.c b/kernel/drivers/mailbox/mailbox.c
index 19b491d29..6a4811f85 100644
--- a/kernel/drivers/mailbox/mailbox.c
+++ b/kernel/drivers/mailbox/mailbox.c
@@ -26,8 +26,6 @@
 static LIST_HEAD(mbox_cons);
 static DEFINE_MUTEX(con_mutex);
 
-static void poll_txdone(unsigned long data);
-
 static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
 {
 	int idx;
@@ -88,7 +86,9 @@ exit:
 	spin_unlock_irqrestore(&chan->lock, flags);
 
 	if (!err && (chan->txdone_method & TXDONE_BY_POLL))
-		poll_txdone((unsigned long)chan->mbox);
+		/* kick start the timer immediately to avoid delays */
+		hrtimer_start(&chan->mbox->poll_hrt, ktime_set(0, 0),
+			      HRTIMER_MODE_REL);
 }
 
 static void tx_tick(struct mbox_chan *chan, int r)
@@ -112,9 +112,10 @@ static void tx_tick(struct mbox_chan *chan, int r)
 		complete(&chan->tx_complete);
 }
 
-static void poll_txdone(unsigned long data)
+static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
 {
-	struct mbox_controller *mbox = (struct mbox_controller *)data;
+	struct mbox_controller *mbox =
+		container_of(hrtimer, struct mbox_controller, poll_hrt);
 	bool txdone, resched = false;
 	int i;
 
@@ -130,9 +131,11 @@ static void poll_txdone(unsigned long data)
 		}
 	}
 
-	if (resched)
-		mod_timer(&mbox->poll, jiffies +
-				msecs_to_jiffies(mbox->txpoll_period));
+	if (resched) {
+		hrtimer_forward_now(hrtimer, ms_to_ktime(mbox->txpoll_period));
+		return HRTIMER_RESTART;
+	}
+	return HRTIMER_NORESTART;
 }
 
 /**
@@ -318,7 +321,7 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 		return ERR_PTR(-ENODEV);
 	}
 
-	chan = NULL;
+	chan = ERR_PTR(-EPROBE_DEFER);
 	list_for_each_entry(mbox, &mbox_cons, node)
 		if (mbox->dev->of_node == spec.np) {
 			chan = mbox->of_xlate(mbox, &spec);
@@ -327,7 +330,12 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 
 	of_node_put(spec.np);
 
-	if (!chan || chan->cl || !try_module_get(mbox->dev->driver->owner)) {
+	if (IS_ERR(chan)) {
+		mutex_unlock(&con_mutex);
+		return chan;
+	}
+
+	if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
 		dev_dbg(dev, "%s: mailbox not free\n", __func__);
 		mutex_unlock(&con_mutex);
 		return ERR_PTR(-EBUSY);
@@ -357,6 +365,35 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 }
 EXPORT_SYMBOL_GPL(mbox_request_channel);
 
+struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
+					      const char *name)
+{
+	struct device_node *np = cl->dev->of_node;
+	struct property *prop;
+	const char *mbox_name;
+	int index = 0;
+
+	if (!np) {
+		dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
+		return ERR_PTR(-ENOSYS);
+	}
+
+	if (!of_get_property(np, "mbox-names", NULL)) {
+		dev_err(cl->dev,
+			"%s() requires an \"mbox-names\" property\n", __func__);
+		return ERR_PTR(-ENOSYS);
+	}
+
+	of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
+		if (!strncmp(name, mbox_name, strlen(name)))
+			break;
+		index++;
+	}
+
+	return mbox_request_channel(cl, index);
+}
+EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
+
 /**
  * mbox_free_channel - The client relinquishes control of a mailbox
  *			channel by this call.
@@ -390,7 +427,7 @@ of_mbox_index_xlate(struct mbox_controller *mbox,
 	int ind = sp->args[0];
 
 	if (ind >= mbox->num_chans)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	return &mbox->chans[ind];
 }
@@ -417,9 +454,9 @@ int mbox_controller_register(struct mbox_controller *mbox)
 		txdone = TXDONE_BY_ACK;
 
 	if (txdone == TXDONE_BY_POLL) {
-		mbox->poll.function = &poll_txdone;
-		mbox->poll.data = (unsigned long)mbox;
-		init_timer(&mbox->poll);
+		hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
+			     HRTIMER_MODE_REL);
+		mbox->poll_hrt.function = txdone_hrtimer;
 	}
 
 	for (i = 0; i < mbox->num_chans; i++) {
@@ -461,7 +498,7 @@ void mbox_controller_unregister(struct mbox_controller *mbox)
 		mbox_free_channel(&mbox->chans[i]);
 
 	if (mbox->txdone_poll)
-		del_timer_sync(&mbox->poll);
+		hrtimer_cancel(&mbox->poll_hrt);
 
 	mutex_unlock(&con_mutex);
 }
diff --git a/kernel/drivers/mailbox/omap-mailbox.c b/kernel/drivers/mailbox/omap-mailbox.c
index 0f332c178..b7f636f15 100644
--- a/kernel/drivers/mailbox/omap-mailbox.c
+++ b/kernel/drivers/mailbox/omap-mailbox.c
@@ -38,6 +38,8 @@
 #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))
@@ -106,6 +108,7 @@ struct omap_mbox_fifo_info {
 	int rx_irq;
 
 	const char *name;
+	bool send_no_irq;
 };
 
 struct omap_mbox {
@@ -119,6 +122,7 @@ struct omap_mbox {
 	u32			ctx[OMAP4_MBOX_NR_REGS];
 	u32			intr_type;
 	struct mbox_chan	*chan;
+	bool			send_no_irq;
 };
 
 /* global variables for the mailbox devices */
@@ -418,6 +422,9 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 		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;
@@ -586,13 +593,27 @@ static void omap_mbox_chan_shutdown(struct mbox_chan *chan)
 	mutex_unlock(&mdev->cfg_lock);
 }
 
-static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
+static int omap_mbox_chan_send_noirq(struct omap_mbox *mbox, void *data)
 {
-	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
 	int ret = -EBUSY;
 
-	if (!mbox)
-		return -EINVAL;
+	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);
@@ -604,7 +625,23 @@ static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
 	return ret;
 }
 
-static struct mbox_chan_ops omap_mbox_chan_ops = {
+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,
@@ -639,18 +676,18 @@ static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,
 
 	mdev = container_of(controller, struct omap_mbox_device, controller);
 	if (WARN_ON(!mdev))
-		return NULL;
+		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 NULL;
+		return ERR_PTR(-ENODEV);
 	}
 
 	mbox = omap_mbox_device_find(mdev, node->name);
 	of_node_put(node);
-	return mbox ? mbox->chan : NULL;
+	return mbox ? mbox->chan : ERR_PTR(-ENOENT);
 }
 
 static int omap_mbox_probe(struct platform_device *pdev)
@@ -732,6 +769,9 @@ static int omap_mbox_probe(struct platform_device *pdev)
 			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;
@@ -791,6 +831,7 @@ static int omap_mbox_probe(struct platform_device *pdev)
 		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;
diff --git a/kernel/drivers/mailbox/pcc.c b/kernel/drivers/mailbox/pcc.c
index 7e91d68a3..45d85aea9 100644
--- a/kernel/drivers/mailbox/pcc.c
+++ b/kernel/drivers/mailbox/pcc.c
@@ -122,7 +122,7 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
 	 */
 	chan = get_pcc_channel(subspace_id);
 
-	if (!chan || chan->cl) {
+	if (IS_ERR(chan) || chan->cl) {
 		dev_err(dev, "Channel not found for idx: %d\n", subspace_id);
 		return ERR_PTR(-EBUSY);
 	}
@@ -198,7 +198,7 @@ static int pcc_send_data(struct mbox_chan *chan, void *data)
 	return 0;
 }
 
-static struct mbox_chan_ops pcc_chan_ops = {
+static const struct mbox_chan_ops pcc_chan_ops = {
 	.send_data = pcc_send_data,
 };
 
@@ -352,4 +352,10 @@ static int __init pcc_init(void)
 
 	return 0;
 }
-device_initcall(pcc_init);
+
+/*
+ * Make PCC init postcore so that users of this mailbox
+ * such as the ACPI Processor driver have it available
+ * at their init.
+ */
+postcore_initcall(pcc_init);
diff --git a/kernel/drivers/mailbox/pl320-ipc.c b/kernel/drivers/mailbox/pl320-ipc.c
index f3755e0aa..f80acb36f 100644
--- a/kernel/drivers/mailbox/pl320-ipc.c
+++ b/kernel/drivers/mailbox/pl320-ipc.c
@@ -195,4 +195,4 @@ static int __init ipc_init(void)
 {
 	return amba_driver_register(&pl320_driver);
 }
-module_init(ipc_init);
+subsys_initcall(ipc_init);