diff --git a/Documentation/devicetree/bindings/char/ipmi/aspeed,ast2400-bt-bmc.txt b/Documentation/devicetree/bindings/char/ipmi/aspeed,ast2400-bt-bmc.txt
new file mode 100644
index 000000000000..fbbacd958240
--- /dev/null
+++ b/Documentation/devicetree/bindings/char/ipmi/aspeed,ast2400-bt-bmc.txt
@@ -0,0 +1,23 @@
+* Aspeed BT (Block Transfer) IPMI interface
+
+The Aspeed SOCs (AST2400 and AST2500) are commonly used as BMCs
+(BaseBoard Management Controllers) and the BT interface can be used to
+perform in-band IPMI communication with their host.
+
+Required properties:
+
+- compatible : should be "aspeed,ast2400-bt-bmc"
+- reg: physical address and size of the registers
+
+Optional properties:
+
+- interrupts: interrupt generated by the BT interface. without an
+  interrupt, the driver will operate in poll mode.
+
+Example:
+
+	ibt@1e789140 {
+		compatible = "aspeed,ast2400-bt-bmc";
+		reg = <0x1e789140 0x18>;
+		interrupts = <8>;
+	};
diff --git a/drivers/Makefile b/drivers/Makefile
index 53abb4a5f736..5a9e7b6b7928 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -21,7 +21,7 @@ obj-y				+= video/
 obj-y				+= idle/
 
 # IPMI must come before ACPI in order to provide IPMI opregion support
-obj-$(CONFIG_IPMI_HANDLER)	+= char/ipmi/
+obj-y				+= char/ipmi/
 
 obj-$(CONFIG_ACPI)		+= acpi/
 obj-$(CONFIG_SFI)		+= sfi/
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index 5a9350b1069a..2c234e3e7513 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -76,3 +76,10 @@ config IPMI_POWEROFF
 	 the IPMI management controller is capable of this.
 
 endif # IPMI_HANDLER
+
+config ASPEED_BT_IPMI_BMC
+	tristate "BT IPMI bmc driver"
+	help
+	  Provides a driver for the BT (Block Transfer) IPMI interface
+	  found on Aspeed SOCs (AST2400 and AST2500). The driver
+	  implements the BMC side of the BT interface.
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index f3ffde1f5f1f..0d98cd91def1 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
 obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
 obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
 obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
+obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
new file mode 100644
index 000000000000..b96cb421e1c2
--- /dev/null
+++ b/drivers/char/ipmi/bt-bmc.c
@@ -0,0 +1,486 @@
+/*
+ * Copyright (c) 2015-2016, IBM Corporation.
+ *
+ * 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/module.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/miscdevice.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/bt-bmc.h>
+
+/*
+ * This is a BMC device used to communicate to the host
+ */
+#define DEVICE_NAME	"ipmi-bt-host"
+
+#define BT_IO_BASE	0xe4
+#define BT_IRQ		10
+
+#define BT_CR0		0x0
+#define   BT_CR0_IO_BASE		16
+#define   BT_CR0_IRQ			12
+#define   BT_CR0_EN_CLR_SLV_RDP		0x8
+#define   BT_CR0_EN_CLR_SLV_WRP		0x4
+#define   BT_CR0_ENABLE_IBT		0x1
+#define BT_CR1		0x4
+#define   BT_CR1_IRQ_H2B	0x01
+#define   BT_CR1_IRQ_HBUSY	0x40
+#define BT_CR2		0x8
+#define   BT_CR2_IRQ_H2B	0x01
+#define   BT_CR2_IRQ_HBUSY	0x40
+#define BT_CR3		0xc
+#define BT_CTRL		0x10
+#define   BT_CTRL_B_BUSY		0x80
+#define   BT_CTRL_H_BUSY		0x40
+#define   BT_CTRL_OEM0			0x20
+#define   BT_CTRL_SMS_ATN		0x10
+#define   BT_CTRL_B2H_ATN		0x08
+#define   BT_CTRL_H2B_ATN		0x04
+#define   BT_CTRL_CLR_RD_PTR		0x02
+#define   BT_CTRL_CLR_WR_PTR		0x01
+#define BT_BMC2HOST	0x14
+#define BT_INTMASK	0x18
+#define   BT_INTMASK_B2H_IRQEN		0x01
+#define   BT_INTMASK_B2H_IRQ		0x02
+#define   BT_INTMASK_BMC_HWRST		0x80
+
+struct bt_bmc {
+	struct device		dev;
+	struct miscdevice	miscdev;
+	void __iomem		*base;
+	int			open_count;
+	int			irq;
+	wait_queue_head_t	queue;
+	struct timer_list	poll_timer;
+};
+
+static u8 bt_inb(struct bt_bmc *bt_bmc, int reg)
+{
+	return ioread8(bt_bmc->base + reg);
+}
+
+static void bt_outb(struct bt_bmc *bt_bmc, u8 data, int reg)
+{
+	iowrite8(data, bt_bmc->base + reg);
+}
+
+static void clr_rd_ptr(struct bt_bmc *bt_bmc)
+{
+	bt_outb(bt_bmc, BT_CTRL_CLR_RD_PTR, BT_CTRL);
+}
+
+static void clr_wr_ptr(struct bt_bmc *bt_bmc)
+{
+	bt_outb(bt_bmc, BT_CTRL_CLR_WR_PTR, BT_CTRL);
+}
+
+static void clr_h2b_atn(struct bt_bmc *bt_bmc)
+{
+	bt_outb(bt_bmc, BT_CTRL_H2B_ATN, BT_CTRL);
+}
+
+static void set_b_busy(struct bt_bmc *bt_bmc)
+{
+	if (!(bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY))
+		bt_outb(bt_bmc, BT_CTRL_B_BUSY, BT_CTRL);
+}
+
+static void clr_b_busy(struct bt_bmc *bt_bmc)
+{
+	if (bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY)
+		bt_outb(bt_bmc, BT_CTRL_B_BUSY, BT_CTRL);
+}
+
+static void set_b2h_atn(struct bt_bmc *bt_bmc)
+{
+	bt_outb(bt_bmc, BT_CTRL_B2H_ATN, BT_CTRL);
+}
+
+static u8 bt_read(struct bt_bmc *bt_bmc)
+{
+	return bt_inb(bt_bmc, BT_BMC2HOST);
+}
+
+static ssize_t bt_readn(struct bt_bmc *bt_bmc, u8 *buf, size_t n)
+{
+	int i;
+
+	for (i = 0; i < n; i++)
+		buf[i] = bt_read(bt_bmc);
+	return n;
+}
+
+static void bt_write(struct bt_bmc *bt_bmc, u8 c)
+{
+	bt_outb(bt_bmc, c, BT_BMC2HOST);
+}
+
+static ssize_t bt_writen(struct bt_bmc *bt_bmc, u8 *buf, size_t n)
+{
+	int i;
+
+	for (i = 0; i < n; i++)
+		bt_write(bt_bmc, buf[i]);
+	return n;
+}
+
+static void set_sms_atn(struct bt_bmc *bt_bmc)
+{
+	bt_outb(bt_bmc, BT_CTRL_SMS_ATN, BT_CTRL);
+}
+
+static struct bt_bmc *file_bt_bmc(struct file *file)
+{
+	return container_of(file->private_data, struct bt_bmc, miscdev);
+}
+
+static int bt_bmc_open(struct inode *inode, struct file *file)
+{
+	struct bt_bmc *bt_bmc = file_bt_bmc(file);
+
+	clr_b_busy(bt_bmc);
+
+	return 0;
+}
+
+#define BT_BMC_BUFFER_SIZE 256
+
+/*
+ * The BT (Block Transfer) interface means that entire messages are
+ * buffered by the host before a notification is sent to the BMC that
+ * there is data to be read. The first byte is the length and the
+ * message data follows. The read operation just tries to capture the
+ * whole before returning it to userspace.
+ */
+static ssize_t bt_bmc_read(struct file *file, char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct bt_bmc *bt_bmc = file_bt_bmc(file);
+	u8 len;
+	int len_byte = 1;
+	u8 kbuffer[BT_BMC_BUFFER_SIZE];
+	ssize_t ret = 0;
+	ssize_t nread;
+
+	if (!access_ok(VERIFY_WRITE, buf, count))
+		return -EFAULT;
+
+	WARN_ON(*ppos);
+
+	if (wait_event_interruptible(bt_bmc->queue,
+				bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_H2B_ATN))
+		return -ERESTARTSYS;
+
+	set_b_busy(bt_bmc);
+	clr_h2b_atn(bt_bmc);
+	clr_rd_ptr(bt_bmc);
+
+	/*
+	 * The BT frames start with the message length, which does not
+	 * include the length byte.
+	 */
+	kbuffer[0] = bt_read(bt_bmc);
+	len = kbuffer[0];
+
+	/* We pass the length back to userspace as well */
+	if (len + 1 > count)
+		len = count - 1;
+
+	while (len) {
+		nread = min_t(ssize_t, len, sizeof(kbuffer) - len_byte);
+
+		bt_readn(bt_bmc, kbuffer + len_byte, nread);
+
+		if (copy_to_user(buf, kbuffer, nread + len_byte)) {
+			ret = -EFAULT;
+			break;
+		}
+		len -= nread;
+		buf += nread + len_byte;
+		ret += nread + len_byte;
+		len_byte = 0;
+	}
+
+	clr_b_busy(bt_bmc);
+
+	return ret;
+}
+
+static ssize_t bt_bmc_write(struct file *file, const char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct bt_bmc *bt_bmc = file_bt_bmc(file);
+	u8 kbuffer[BT_BMC_BUFFER_SIZE];
+	ssize_t ret = 0;
+	ssize_t nwritten;
+
+	if (!access_ok(VERIFY_READ, buf, count))
+		return -EFAULT;
+
+	WARN_ON(*ppos);
+
+	/* There's no interrupt for clearing bmc busy so we have to
+	 * poll
+	 */
+	if (wait_event_interruptible(bt_bmc->queue,
+				!(bt_inb(bt_bmc, BT_CTRL) &
+					(BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN))))
+		return -ERESTARTSYS;
+
+	clr_wr_ptr(bt_bmc);
+
+	while (count) {
+		nwritten = min_t(ssize_t, count, sizeof(kbuffer));
+		if (copy_from_user(&kbuffer, buf, nwritten)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		bt_writen(bt_bmc, kbuffer, nwritten);
+
+		count -= nwritten;
+		buf += nwritten;
+		ret += nwritten;
+	}
+
+	set_b2h_atn(bt_bmc);
+
+	return ret;
+}
+
+static long bt_bmc_ioctl(struct file *file, unsigned int cmd,
+		unsigned long param)
+{
+	struct bt_bmc *bt_bmc = file_bt_bmc(file);
+
+	switch (cmd) {
+	case BT_BMC_IOCTL_SMS_ATN:
+		set_sms_atn(bt_bmc);
+		return 0;
+	}
+	return -EINVAL;
+}
+
+static int bt_bmc_release(struct inode *inode, struct file *file)
+{
+	struct bt_bmc *bt_bmc = file_bt_bmc(file);
+
+	set_b_busy(bt_bmc);
+	return 0;
+}
+
+static unsigned int bt_bmc_poll(struct file *file, poll_table *wait)
+{
+	struct bt_bmc *bt_bmc = file_bt_bmc(file);
+	unsigned int mask = 0;
+	uint8_t ctrl;
+
+	poll_wait(file, &bt_bmc->queue, wait);
+
+	ctrl = bt_inb(bt_bmc, BT_CTRL);
+
+	if (ctrl & BT_CTRL_H2B_ATN)
+		mask |= POLLIN;
+
+	if (!(ctrl & (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN)))
+		mask |= POLLOUT;
+
+	return mask;
+}
+
+static const struct file_operations bt_bmc_fops = {
+	.owner		= THIS_MODULE,
+	.open		= bt_bmc_open,
+	.read		= bt_bmc_read,
+	.write		= bt_bmc_write,
+	.release	= bt_bmc_release,
+	.poll		= bt_bmc_poll,
+	.unlocked_ioctl	= bt_bmc_ioctl,
+};
+
+static void poll_timer(unsigned long data)
+{
+	struct bt_bmc *bt_bmc = (void *)data;
+
+	bt_bmc->poll_timer.expires += msecs_to_jiffies(500);
+	wake_up(&bt_bmc->queue);
+	add_timer(&bt_bmc->poll_timer);
+}
+
+static irqreturn_t bt_bmc_irq(int irq, void *arg)
+{
+	struct bt_bmc *bt_bmc = arg;
+	uint32_t reg;
+
+	reg = ioread32(bt_bmc->base + BT_CR2);
+	reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
+	if (!reg)
+		return IRQ_NONE;
+
+	/* ack pending IRQs */
+	iowrite32(reg, bt_bmc->base + BT_CR2);
+
+	wake_up(&bt_bmc->queue);
+	return IRQ_HANDLED;
+}
+
+static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
+		struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	uint32_t reg;
+	int rc;
+
+	bt_bmc->irq = platform_get_irq(pdev, 0);
+	if (!bt_bmc->irq)
+		return -ENODEV;
+
+	rc = devm_request_irq(dev, bt_bmc->irq, bt_bmc_irq, IRQF_SHARED,
+			DEVICE_NAME, bt_bmc);
+	if (rc < 0) {
+		dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
+		bt_bmc->irq = 0;
+		return rc;
+	}
+
+	/* Configure IRQs on the bmc clearing the H2B and HBUSY bits;
+	 * H2B will be asserted when the bmc has data for us; HBUSY
+	 * will be cleared (along with B2H) when we can write the next
+	 * message to the BT buffer
+	 */
+	reg = ioread32(bt_bmc->base + BT_CR1);
+	reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY;
+	iowrite32(reg, bt_bmc->base + BT_CR1);
+
+	return 0;
+}
+
+static int bt_bmc_probe(struct platform_device *pdev)
+{
+	struct bt_bmc *bt_bmc;
+	struct device *dev;
+	struct resource *res;
+	int rc;
+
+	if (!pdev || !pdev->dev.of_node)
+		return -ENODEV;
+
+	dev = &pdev->dev;
+	dev_info(dev, "Found bt bmc device\n");
+
+	bt_bmc = devm_kzalloc(dev, sizeof(*bt_bmc), GFP_KERNEL);
+	if (!bt_bmc)
+		return -ENOMEM;
+
+	dev_set_drvdata(&pdev->dev, bt_bmc);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "Unable to find resources\n");
+		rc = -ENXIO;
+		goto out_free;
+	}
+
+	bt_bmc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (!bt_bmc->base) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+
+	init_waitqueue_head(&bt_bmc->queue);
+
+	bt_bmc->miscdev.minor	= MISC_DYNAMIC_MINOR,
+	bt_bmc->miscdev.name	= DEVICE_NAME,
+	bt_bmc->miscdev.fops	= &bt_bmc_fops,
+	bt_bmc->miscdev.parent = dev;
+	rc = misc_register(&bt_bmc->miscdev);
+	if (rc) {
+		dev_err(dev, "Unable to register device\n");
+		goto out_unmap;
+	}
+
+	bt_bmc_config_irq(bt_bmc, pdev);
+
+	if (bt_bmc->irq) {
+		dev_info(dev, "Using IRQ %d\n", bt_bmc->irq);
+	} else {
+		dev_info(dev, "No IRQ; using timer\n");
+		setup_timer(&bt_bmc->poll_timer, poll_timer,
+				(unsigned long)bt_bmc);
+		bt_bmc->poll_timer.expires = jiffies + msecs_to_jiffies(10);
+		add_timer(&bt_bmc->poll_timer);
+	}
+
+	iowrite32((BT_IO_BASE << BT_CR0_IO_BASE) |
+		  (BT_IRQ << BT_CR0_IRQ) |
+		  BT_CR0_EN_CLR_SLV_RDP |
+		  BT_CR0_EN_CLR_SLV_WRP |
+		  BT_CR0_ENABLE_IBT,
+		  bt_bmc->base + BT_CR0);
+
+	clr_b_busy(bt_bmc);
+
+	return 0;
+
+out_unmap:
+	devm_iounmap(&pdev->dev, bt_bmc->base);
+
+out_free:
+	devm_kfree(dev, bt_bmc);
+	return rc;
+
+}
+
+static int bt_bmc_remove(struct platform_device *pdev)
+{
+	struct bt_bmc *bt_bmc = dev_get_drvdata(&pdev->dev);
+
+	misc_deregister(&bt_bmc->miscdev);
+	if (!bt_bmc->irq)
+		del_timer_sync(&bt_bmc->poll_timer);
+	devm_iounmap(&pdev->dev, bt_bmc->base);
+	devm_kfree(&pdev->dev, bt_bmc);
+	bt_bmc = NULL;
+
+	return 0;
+}
+
+static const struct of_device_id bt_bmc_match[] = {
+	{ .compatible = "aspeed,ast2400-bt-bmc" },
+	{ },
+};
+
+static struct platform_driver bt_bmc_driver = {
+	.driver = {
+		.name		= DEVICE_NAME,
+		.of_match_table = bt_bmc_match,
+	},
+	.probe = bt_bmc_probe,
+	.remove = bt_bmc_remove,
+};
+
+module_platform_driver(bt_bmc_driver);
+
+MODULE_DEVICE_TABLE(of, bt_bmc_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alistair Popple <alistair@popple.id.au>");
+MODULE_DESCRIPTION("Linux device interface to the BT interface");
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 185f8ea2702f..17b12942c67d 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -74,6 +74,7 @@ header-y += bpf_common.h
 header-y += bpf.h
 header-y += bpqether.h
 header-y += bsg.h
+header-y += bt-bmc.h
 header-y += btrfs.h
 header-y += can.h
 header-y += capability.h
diff --git a/include/uapi/linux/bt-bmc.h b/include/uapi/linux/bt-bmc.h
new file mode 100644
index 000000000000..d9ec766a63d0
--- /dev/null
+++ b/include/uapi/linux/bt-bmc.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2015-2016, IBM Corporation.
+ *
+ * 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.
+ */
+
+#ifndef _UAPI_LINUX_BT_BMC_H
+#define _UAPI_LINUX_BT_BMC_H
+
+#include <linux/ioctl.h>
+
+#define __BT_BMC_IOCTL_MAGIC	0xb1
+#define BT_BMC_IOCTL_SMS_ATN	_IO(__BT_BMC_IOCTL_MAGIC, 0x00)
+
+#endif /* _UAPI_LINUX_BT_BMC_H */
