diff --git a/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-ibt-bmc.txt b/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-ibt-bmc.txt
index 028268fd99ee..c9902fd4b38b 100644
--- a/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-ibt-bmc.txt
+++ b/Documentation/devicetree/bindings/ipmi/aspeed,ast2400-ibt-bmc.txt
@@ -9,6 +9,7 @@ Required properties:
 - compatible : should be one of
 	"aspeed,ast2400-ibt-bmc"
 	"aspeed,ast2500-ibt-bmc"
+	"aspeed,ast2600-ibt-bmc"
 - reg: physical address and size of the registers
 
 Optional properties:
diff --git a/Documentation/devicetree/bindings/ipmi/ipmi-ipmb.yaml b/Documentation/devicetree/bindings/ipmi/ipmi-ipmb.yaml
new file mode 100644
index 000000000000..93d8f8e88cf5
--- /dev/null
+++ b/Documentation/devicetree/bindings/ipmi/ipmi-ipmb.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ipmi/ipmi-ipmb.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: IPMI IPMB device bindings
+
+description: IPMI IPMB device bindings
+
+maintainers:
+  - Corey Minyard <cminyard@mvista.com>
+
+properties:
+  compatible:
+    enum:
+      - ipmi-ipmb
+
+  device_type:
+    items:
+      - const: "ipmi"
+
+  reg:
+    maxItems: 1
+
+  bmcaddr:
+    $ref: /schemas/types.yaml#/definitions/uint8
+    description: The address of the BMC on the IPMB bus.  Defaults to 0x20.
+
+  retry-time:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Time between retries of sends, in milliseconds.  Defaults to 250.
+
+  max-retries:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Number of retries before a failure is declared.  Defaults to 1.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            ipmi-ipmb@40 {
+                    compatible = "ipmi-ipmb";
+                    device_type = "ipmi";
+                    reg = <0x40>;
+                    bmcaddr = /bits/ 8 <0x20>;
+                    retry-time = <250>;
+                    max-retries = <1>;
+            };
+    };
diff --git a/Documentation/driver-api/ipmi.rst b/Documentation/driver-api/ipmi.rst
index bc281f10ce4b..e224e47b6b09 100644
--- a/Documentation/driver-api/ipmi.rst
+++ b/Documentation/driver-api/ipmi.rst
@@ -166,8 +166,8 @@ and the type is IPMI_SYSTEM_INTERFACE_ADDR_TYPE.  This is used for talking
 straight to the BMC on the current card.  The channel must be
 IPMI_BMC_CHANNEL.
 
-Messages that are destined to go out on the IPMB bus use the
-IPMI_IPMB_ADDR_TYPE address type.  The format is::
+Messages that are destined to go out on the IPMB bus going through the
+BMC use the IPMI_IPMB_ADDR_TYPE address type.  The format is::
 
   struct ipmi_ipmb_addr
   {
@@ -181,6 +181,23 @@ The "channel" here is generally zero, but some devices support more
 than one channel, it corresponds to the channel as defined in the IPMI
 spec.
 
+There is also an IPMB direct address for a situation where the sender
+is directly on an IPMB bus and doesn't have to go through the BMC.
+You can send messages to a specific management controller (MC) on the
+IPMB using the IPMI_IPMB_DIRECT_ADDR_TYPE with the following format::
+
+  struct ipmi_ipmb_direct_addr
+  {
+	int           addr_type;
+	short         channel;
+	unsigned char slave_addr;
+	unsigned char rq_lun;
+	unsigned char rs_lun;
+  };
+
+The channel is always zero.  You can also receive commands from other
+MCs that you have registered to handle and respond to them, so you can
+use this to implement a management controller on a bus..
 
 Messages
 --------
@@ -348,6 +365,10 @@ user may be registered for each netfn/cmd/channel, but different users
 may register for different commands, or the same command if the
 channel bitmasks do not overlap.
 
+To respond to a received command, set the response bit in the returned
+netfn, use the address from the received message, and use the same
+msgid that you got in the receive message.
+
 From userland, equivalent IOCTLs are provided to do these functions.
 
 
@@ -570,6 +591,45 @@ web page.
 The driver supports a hot add and remove of interfaces through the I2C
 sysfs interface.
 
+The IPMI IPMB Driver
+--------------------
+
+This driver is for supporting a system that sits on an IPMB bus; it
+allows the interface to look like a normal IPMI interface.  Sending
+system interface addressed messages to it will cause the message to go
+to the registered BMC on the system (default at IPMI address 0x20).
+
+It also allows you to directly address other MCs on the bus using the
+ipmb direct addressing.  You can receive commands from other MCs on
+the bus and they will be handled through the normal received command
+mechanism described above.
+
+Parameters are::
+
+  ipmi_ipmb.bmcaddr=<address to use for system interface addresses messages>
+	ipmi_ipmb.retry_time_ms=<Time between retries on IPMB>
+	ipmi_ipmb.max_retries=<Number of times to retry a message>
+
+Loading the module will not result in the driver automatcially
+starting unless there is device tree information setting it up.  If
+you want to instantiate one of these by hand, do::
+
+  echo ipmi-ipmb <addr> > /sys/class/i2c-dev/i2c-<n>/device/new_device
+
+Note that the address you give here is the I2C address, not the IPMI
+address.  So if you want your MC address to be 0x60, you put 0x30
+here.  See the I2C driver info for more details.
+
+Command bridging to other IPMB busses through this interface does not
+work.  The receive message queue is not implemented, by design.  There
+is only one receive message queue on a BMC, and that is meant for the
+host drivers, not something on the IPMB bus.
+
+A BMC may have multiple IPMB busses, which bus your device sits on
+depends on how the system is wired.  You can fetch the channels with
+"ipmitool channel info <n>" where <n> is the channel, with the
+channels being 0-7 and try the IPMB channels.
+
 Other Pieces
 ------------
 
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index 249b31197eea..b061e6b513ed 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -69,12 +69,21 @@ config IPMI_SI
 
 config IPMI_SSIF
 	tristate 'IPMI SMBus handler (SSIF)'
-	select I2C
+	depends on I2C
 	help
 	  Provides a driver for a SMBus interface to a BMC, meaning that you
 	  have a driver that must be accessed over an I2C bus instead of a
 	  standard interface.  This module requires I2C support.
 
+config IPMI_IPMB
+	tristate 'IPMI IPMB interface'
+	depends on I2C && I2C_SLAVE
+	help
+	  Provides a driver for a system running right on the IPMB bus.
+	  It supports normal system interface messages to a BMC on the IPMB
+	  bus, and it also supports direct messaging on the bus using
+	  IPMB direct messages.  This module requires I2C support.
+
 config IPMI_POWERNV
 	depends on PPC_POWERNV
 	tristate 'POWERNV (OPAL firmware) IPMI interface'
diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
index 84f47d18007f..7ce790efad92 100644
--- a/drivers/char/ipmi/Makefile
+++ b/drivers/char/ipmi/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_IPMI_SI) += ipmi_si.o
 obj-$(CONFIG_IPMI_DMI_DECODE) += ipmi_dmi.o
 obj-$(CONFIG_IPMI_PLAT_DATA) += ipmi_plat_data.o
 obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
+obj-$(CONFIG_IPMI_IPMB) += ipmi_ipmb.o
 obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
 obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
 obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
index 6e3d247b55d1..7450904e330a 100644
--- a/drivers/char/ipmi/bt-bmc.c
+++ b/drivers/char/ipmi/bt-bmc.c
@@ -8,13 +8,11 @@
 #include <linux/errno.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
-#include <linux/mfd/syscon.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/poll.h>
-#include <linux/regmap.h>
 #include <linux/sched.h>
 #include <linux/timer.h>
 
@@ -59,8 +57,7 @@
 struct bt_bmc {
 	struct device		dev;
 	struct miscdevice	miscdev;
-	struct regmap		*map;
-	int			offset;
+	void __iomem		*base;
 	int			irq;
 	wait_queue_head_t	queue;
 	struct timer_list	poll_timer;
@@ -69,29 +66,14 @@ struct bt_bmc {
 
 static atomic_t open_count = ATOMIC_INIT(0);
 
-static const struct regmap_config bt_regmap_cfg = {
-	.reg_bits = 32,
-	.val_bits = 32,
-	.reg_stride = 4,
-};
-
 static u8 bt_inb(struct bt_bmc *bt_bmc, int reg)
 {
-	uint32_t val = 0;
-	int rc;
-
-	rc = regmap_read(bt_bmc->map, bt_bmc->offset + reg, &val);
-	WARN(rc != 0, "regmap_read() failed: %d\n", rc);
-
-	return rc == 0 ? (u8) val : 0;
+	return readb(bt_bmc->base + reg);
 }
 
 static void bt_outb(struct bt_bmc *bt_bmc, u8 data, int reg)
 {
-	int rc;
-
-	rc = regmap_write(bt_bmc->map, bt_bmc->offset + reg, data);
-	WARN(rc != 0, "regmap_write() failed: %d\n", rc);
+	writeb(data, bt_bmc->base + reg);
 }
 
 static void clr_rd_ptr(struct bt_bmc *bt_bmc)
@@ -376,18 +358,15 @@ static irqreturn_t bt_bmc_irq(int irq, void *arg)
 {
 	struct bt_bmc *bt_bmc = arg;
 	u32 reg;
-	int rc;
 
-	rc = regmap_read(bt_bmc->map, bt_bmc->offset + BT_CR2, &reg);
-	if (rc)
-		return IRQ_NONE;
+	reg = readl(bt_bmc->base + BT_CR2);
 
 	reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
 	if (!reg)
 		return IRQ_NONE;
 
 	/* ack pending IRQs */
-	regmap_write(bt_bmc->map, bt_bmc->offset + BT_CR2, reg);
+	writel(reg, bt_bmc->base + BT_CR2);
 
 	wake_up(&bt_bmc->queue);
 	return IRQ_HANDLED;
@@ -398,6 +377,7 @@ static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
 {
 	struct device *dev = &pdev->dev;
 	int rc;
+	u32 reg;
 
 	bt_bmc->irq = platform_get_irq_optional(pdev, 0);
 	if (bt_bmc->irq < 0)
@@ -417,11 +397,11 @@ static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
 	 * will be cleared (along with B2H) when we can write the next
 	 * message to the BT buffer
 	 */
-	rc = regmap_update_bits(bt_bmc->map, bt_bmc->offset + BT_CR1,
-				(BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY),
-				(BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY));
+	reg = readl(bt_bmc->base + BT_CR1);
+	reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY;
+	writel(reg, bt_bmc->base + BT_CR1);
 
-	return rc;
+	return 0;
 }
 
 static int bt_bmc_probe(struct platform_device *pdev)
@@ -439,25 +419,9 @@ static int bt_bmc_probe(struct platform_device *pdev)
 
 	dev_set_drvdata(&pdev->dev, bt_bmc);
 
-	bt_bmc->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
-	if (IS_ERR(bt_bmc->map)) {
-		void __iomem *base;
-
-		/*
-		 * Assume it's not the MFD-based devicetree description, in
-		 * which case generate a regmap ourselves
-		 */
-		base = devm_platform_ioremap_resource(pdev, 0);
-		if (IS_ERR(base))
-			return PTR_ERR(base);
-
-		bt_bmc->map = devm_regmap_init_mmio(dev, base, &bt_regmap_cfg);
-		bt_bmc->offset = 0;
-	} else {
-		rc = of_property_read_u32(dev->of_node, "reg", &bt_bmc->offset);
-		if (rc)
-			return rc;
-	}
+	bt_bmc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(bt_bmc->base))
+		return PTR_ERR(bt_bmc->base);
 
 	mutex_init(&bt_bmc->mutex);
 	init_waitqueue_head(&bt_bmc->queue);
@@ -483,12 +447,12 @@ static int bt_bmc_probe(struct platform_device *pdev)
 		add_timer(&bt_bmc->poll_timer);
 	}
 
-	regmap_write(bt_bmc->map, bt_bmc->offset + BT_CR0,
-		     (BT_IO_BASE << BT_CR0_IO_BASE) |
+	writel((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_CR0_ENABLE_IBT,
+		bt_bmc->base + BT_CR0);
 
 	clr_b_busy(bt_bmc);
 
@@ -508,6 +472,7 @@ static int bt_bmc_remove(struct platform_device *pdev)
 static const struct of_device_id bt_bmc_match[] = {
 	{ .compatible = "aspeed,ast2400-ibt-bmc" },
 	{ .compatible = "aspeed,ast2500-ibt-bmc" },
+	{ .compatible = "aspeed,ast2600-ibt-bmc" },
 	{ },
 };
 
diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index 3dd1d5abb298..d160fa4c73fe 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -247,11 +247,13 @@ static int handle_recv(struct ipmi_file_private *priv,
 
 	if (msg->msg.data_len > 0) {
 		if (rsp->msg.data_len < msg->msg.data_len) {
-			rv2 = -EMSGSIZE;
-			if (trunc)
+			if (trunc) {
+				rv2 = -EMSGSIZE;
 				msg->msg.data_len = rsp->msg.data_len;
-			else
+			} else {
+				rv = -EMSGSIZE;
 				goto recv_putback_on_err;
+			}
 		}
 
 		if (copy_to_user(rsp->msg.data,
diff --git a/drivers/char/ipmi/ipmi_ipmb.c b/drivers/char/ipmi/ipmi_ipmb.c
new file mode 100644
index 000000000000..ba0c2d2c6bbe
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_ipmb.c
@@ -0,0 +1,539 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Driver to talk to a remote management controller on IPMB.
+ */
+
+#include <linux/acpi.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/semaphore.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
+#include <linux/ipmi_msgdefs.h>
+#include <linux/ipmi_smi.h>
+
+#define DEVICE_NAME "ipmi-ipmb"
+
+static int bmcaddr = 0x20;
+module_param(bmcaddr, int, 0644);
+MODULE_PARM_DESC(bmcaddr, "Address to use for BMC.");
+
+static unsigned int retry_time_ms = 250;
+module_param(retry_time_ms, uint, 0644);
+MODULE_PARM_DESC(max_retries, "Timeout time between retries, in milliseconds.");
+
+static unsigned int max_retries = 1;
+module_param(max_retries, uint, 0644);
+MODULE_PARM_DESC(max_retries, "Max resends of a command before timing out.");
+
+/* Add room for the two slave addresses, two checksums, and rqSeq. */
+#define IPMB_MAX_MSG_LEN (IPMI_MAX_MSG_LENGTH + 5)
+
+struct ipmi_ipmb_dev {
+	struct ipmi_smi *intf;
+	struct i2c_client *client;
+
+	struct ipmi_smi_handlers handlers;
+
+	bool ready;
+
+	u8 curr_seq;
+
+	u8 bmcaddr;
+	u32 retry_time_ms;
+	u32 max_retries;
+
+	struct ipmi_smi_msg *next_msg;
+	struct ipmi_smi_msg *working_msg;
+
+	/* Transmit thread. */
+	struct task_struct *thread;
+	struct semaphore wake_thread;
+	struct semaphore got_rsp;
+	spinlock_t lock;
+	bool stopping;
+
+	u8 xmitmsg[IPMB_MAX_MSG_LEN];
+	unsigned int xmitlen;
+
+	u8 rcvmsg[IPMB_MAX_MSG_LEN];
+	unsigned int rcvlen;
+	bool overrun;
+};
+
+static bool valid_ipmb(struct ipmi_ipmb_dev *iidev)
+{
+	u8 *msg = iidev->rcvmsg;
+	u8 netfn;
+
+	if (iidev->overrun)
+		return false;
+
+	/* Minimum message size. */
+	if (iidev->rcvlen < 7)
+		return false;
+
+	/* Is it a response? */
+	netfn = msg[1] >> 2;
+	if (netfn & 1) {
+		/* Response messages have an added completion code. */
+		if (iidev->rcvlen < 8)
+			return false;
+	}
+
+	if (ipmb_checksum(msg, 3) != 0)
+		return false;
+	if (ipmb_checksum(msg + 3, iidev->rcvlen - 3) != 0)
+		return false;
+
+	return true;
+}
+
+static void ipmi_ipmb_check_msg_done(struct ipmi_ipmb_dev *iidev)
+{
+	struct ipmi_smi_msg *imsg = NULL;
+	u8 *msg = iidev->rcvmsg;
+	bool is_cmd;
+	unsigned long flags;
+
+	if (iidev->rcvlen == 0)
+		return;
+	if (!valid_ipmb(iidev))
+		goto done;
+
+	is_cmd = ((msg[1] >> 2) & 1) == 0;
+
+	if (is_cmd) {
+		/* Ignore commands until we are up. */
+		if (!iidev->ready)
+			goto done;
+
+		/* It's a command, allocate a message for it. */
+		imsg = ipmi_alloc_smi_msg();
+		if (!imsg)
+			goto done;
+		imsg->type = IPMI_SMI_MSG_TYPE_IPMB_DIRECT;
+		imsg->data_size = 0;
+	} else {
+		spin_lock_irqsave(&iidev->lock, flags);
+		if (iidev->working_msg) {
+			u8 seq = msg[4] >> 2;
+			bool xmit_rsp = (iidev->working_msg->data[0] >> 2) & 1;
+
+			/*
+			 * Responses should carry the sequence we sent
+			 * them with.  If it's a transmitted response,
+			 * ignore it.  And if the message hasn't been
+			 * transmitted, ignore it.
+			 */
+			if (!xmit_rsp && seq == iidev->curr_seq) {
+				iidev->curr_seq = (iidev->curr_seq + 1) & 0x3f;
+
+				imsg = iidev->working_msg;
+				iidev->working_msg = NULL;
+			}
+		}
+		spin_unlock_irqrestore(&iidev->lock, flags);
+	}
+
+	if (!imsg)
+		goto done;
+
+	if (imsg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+		imsg->rsp[0] = msg[1]; /* NetFn/LUN */
+		/*
+		 * Keep the source address, rqSeq.  Drop the trailing
+		 * checksum.
+		 */
+		memcpy(imsg->rsp + 1, msg + 3, iidev->rcvlen - 4);
+		imsg->rsp_size = iidev->rcvlen - 3;
+	} else {
+		imsg->rsp[0] = msg[1]; /* NetFn/LUN */
+		/*
+		 * Skip the source address, rqSeq.  Drop the trailing
+		 * checksum.
+		 */
+		memcpy(imsg->rsp + 1, msg + 5, iidev->rcvlen - 6);
+		imsg->rsp_size = iidev->rcvlen - 5;
+	}
+	ipmi_smi_msg_received(iidev->intf, imsg);
+	if (!is_cmd)
+		up(&iidev->got_rsp);
+
+done:
+	iidev->overrun = false;
+	iidev->rcvlen = 0;
+}
+
+/*
+ * The IPMB protocol only supports i2c writes so there is no need to
+ * support I2C_SLAVE_READ* events, except to know if the other end has
+ * issued a read without going to stop mode.
+ */
+static int ipmi_ipmb_slave_cb(struct i2c_client *client,
+			      enum i2c_slave_event event, u8 *val)
+{
+	struct ipmi_ipmb_dev *iidev = i2c_get_clientdata(client);
+
+	switch (event) {
+	case I2C_SLAVE_WRITE_REQUESTED:
+		ipmi_ipmb_check_msg_done(iidev);
+		/*
+		 * First byte is the slave address, to ease the checksum
+		 * calculation.
+		 */
+		iidev->rcvmsg[0] = client->addr << 1;
+		iidev->rcvlen = 1;
+		break;
+
+	case I2C_SLAVE_WRITE_RECEIVED:
+		if (iidev->rcvlen >= sizeof(iidev->rcvmsg))
+			iidev->overrun = true;
+		else
+			iidev->rcvmsg[iidev->rcvlen++] = *val;
+		break;
+
+	case I2C_SLAVE_READ_REQUESTED:
+	case I2C_SLAVE_STOP:
+		ipmi_ipmb_check_msg_done(iidev);
+		break;
+
+	case I2C_SLAVE_READ_PROCESSED:
+		break;
+	}
+
+	return 0;
+}
+
+static void ipmi_ipmb_send_response(struct ipmi_ipmb_dev *iidev,
+				    struct ipmi_smi_msg *msg, u8 cc)
+{
+	if ((msg->data[0] >> 2) & 1) {
+		/*
+		 * It's a response being sent, we needto return a
+		 * response response.  Fake a send msg command
+		 * response with channel 0.  This will always be ipmb
+		 * direct.
+		 */
+		msg->data[0] = (IPMI_NETFN_APP_REQUEST | 1) << 2;
+		msg->data[3] = IPMI_SEND_MSG_CMD;
+		msg->data[4] = cc;
+		msg->data_size = 5;
+	}
+	msg->rsp[0] = msg->data[0] | (1 << 2);
+	if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+		msg->rsp[1] = msg->data[1];
+		msg->rsp[2] = msg->data[2];
+		msg->rsp[3] = msg->data[3];
+		msg->rsp[4] = cc;
+		msg->rsp_size = 5;
+	} else {
+		msg->rsp[1] = msg->data[1];
+		msg->rsp[2] = cc;
+		msg->rsp_size = 3;
+	}
+	ipmi_smi_msg_received(iidev->intf, msg);
+}
+
+static void ipmi_ipmb_format_for_xmit(struct ipmi_ipmb_dev *iidev,
+				      struct ipmi_smi_msg *msg)
+{
+	if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+		iidev->xmitmsg[0] = msg->data[1];
+		iidev->xmitmsg[1] = msg->data[0];
+		memcpy(iidev->xmitmsg + 4, msg->data + 2, msg->data_size - 2);
+		iidev->xmitlen = msg->data_size + 2;
+	} else {
+		iidev->xmitmsg[0] = iidev->bmcaddr;
+		iidev->xmitmsg[1] = msg->data[0];
+		iidev->xmitmsg[4] = 0;
+		memcpy(iidev->xmitmsg + 5, msg->data + 1, msg->data_size - 1);
+		iidev->xmitlen = msg->data_size + 4;
+	}
+	iidev->xmitmsg[3] = iidev->client->addr << 1;
+	if (((msg->data[0] >> 2) & 1) == 0)
+		/* If it's a command, put in our own sequence number. */
+		iidev->xmitmsg[4] = ((iidev->xmitmsg[4] & 0x03) |
+				     (iidev->curr_seq << 2));
+
+	/* Now add on the final checksums. */
+	iidev->xmitmsg[2] = ipmb_checksum(iidev->xmitmsg, 2);
+	iidev->xmitmsg[iidev->xmitlen] =
+		ipmb_checksum(iidev->xmitmsg + 3, iidev->xmitlen - 3);
+	iidev->xmitlen++;
+}
+
+static int ipmi_ipmb_thread(void *data)
+{
+	struct ipmi_ipmb_dev *iidev = data;
+
+	while (!kthread_should_stop()) {
+		long ret;
+		struct i2c_msg i2c_msg;
+		struct ipmi_smi_msg *msg = NULL;
+		unsigned long flags;
+		unsigned int retries = 0;
+
+		/* Wait for a message to send */
+		ret = down_interruptible(&iidev->wake_thread);
+		if (iidev->stopping)
+			break;
+		if (ret)
+			continue;
+
+		spin_lock_irqsave(&iidev->lock, flags);
+		if (iidev->next_msg) {
+			msg = iidev->next_msg;
+			iidev->next_msg = NULL;
+		}
+		spin_unlock_irqrestore(&iidev->lock, flags);
+		if (!msg)
+			continue;
+
+		ipmi_ipmb_format_for_xmit(iidev, msg);
+
+retry:
+		i2c_msg.len = iidev->xmitlen - 1;
+		if (i2c_msg.len > 32) {
+			ipmi_ipmb_send_response(iidev, msg,
+						IPMI_REQ_LEN_EXCEEDED_ERR);
+			continue;
+		}
+
+		i2c_msg.addr = iidev->xmitmsg[0] >> 1;
+		i2c_msg.flags = 0;
+		i2c_msg.buf = iidev->xmitmsg + 1;
+
+		/* Rely on i2c_transfer for a barrier. */
+		iidev->working_msg = msg;
+
+		ret = i2c_transfer(iidev->client->adapter, &i2c_msg, 1);
+
+		if ((msg->data[0] >> 2) & 1) {
+			/*
+			 * It's a response, nothing will be returned
+			 * by the other end.
+			 */
+
+			iidev->working_msg = NULL;
+			ipmi_ipmb_send_response(iidev, msg,
+						ret < 0 ? IPMI_BUS_ERR : 0);
+			continue;
+		}
+		if (ret < 0) {
+			iidev->working_msg = NULL;
+			ipmi_ipmb_send_response(iidev, msg, IPMI_BUS_ERR);
+			continue;
+		}
+
+		/* A command was sent, wait for its response. */
+		ret = down_timeout(&iidev->got_rsp,
+				   msecs_to_jiffies(iidev->retry_time_ms));
+
+		/*
+		 * Grab the message if we can.  If the handler hasn't
+		 * already handled it, the message will still be there.
+		 */
+		spin_lock_irqsave(&iidev->lock, flags);
+		msg = iidev->working_msg;
+		iidev->working_msg = NULL;
+		spin_unlock_irqrestore(&iidev->lock, flags);
+
+		if (!msg && ret) {
+			/*
+			 * If working_msg is not set and we timed out,
+			 * that means the message grabbed by
+			 * check_msg_done before we could grab it
+			 * here.  Wait again for check_msg_done to up
+			 * the semaphore.
+			 */
+			down(&iidev->got_rsp);
+		} else if (msg && ++retries <= iidev->max_retries) {
+			spin_lock_irqsave(&iidev->lock, flags);
+			iidev->working_msg = msg;
+			spin_unlock_irqrestore(&iidev->lock, flags);
+			goto retry;
+		}
+
+		if (msg)
+			ipmi_ipmb_send_response(iidev, msg, IPMI_TIMEOUT_ERR);
+	}
+
+	if (iidev->next_msg)
+		/* Return an unspecified error. */
+		ipmi_ipmb_send_response(iidev, iidev->next_msg, 0xff);
+
+	return 0;
+}
+
+static int ipmi_ipmb_start_processing(void *send_info,
+				      struct ipmi_smi *new_intf)
+{
+	struct ipmi_ipmb_dev *iidev = send_info;
+
+	iidev->intf = new_intf;
+	iidev->ready = true;
+	return 0;
+}
+
+static void ipmi_ipmb_stop_thread(struct ipmi_ipmb_dev *iidev)
+{
+	if (iidev->thread) {
+		struct task_struct *t = iidev->thread;
+
+		iidev->thread = NULL;
+		iidev->stopping = true;
+		up(&iidev->wake_thread);
+		up(&iidev->got_rsp);
+		kthread_stop(t);
+	}
+}
+
+static void ipmi_ipmb_shutdown(void *send_info)
+{
+	struct ipmi_ipmb_dev *iidev = send_info;
+
+	ipmi_ipmb_stop_thread(iidev);
+}
+
+static void ipmi_ipmb_sender(void *send_info,
+			     struct ipmi_smi_msg *msg)
+{
+	struct ipmi_ipmb_dev *iidev = send_info;
+	unsigned long flags;
+
+	spin_lock_irqsave(&iidev->lock, flags);
+	BUG_ON(iidev->next_msg);
+
+	iidev->next_msg = msg;
+	spin_unlock_irqrestore(&iidev->lock, flags);
+
+	up(&iidev->wake_thread);
+}
+
+static void ipmi_ipmb_request_events(void *send_info)
+{
+	/* We don't fetch events here. */
+}
+
+static int ipmi_ipmb_remove(struct i2c_client *client)
+{
+	struct ipmi_ipmb_dev *iidev = i2c_get_clientdata(client);
+
+	if (iidev->client) {
+		iidev->client = NULL;
+		i2c_slave_unregister(client);
+	}
+	ipmi_ipmb_stop_thread(iidev);
+
+	return 0;
+}
+
+static int ipmi_ipmb_probe(struct i2c_client *client,
+			   const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ipmi_ipmb_dev *iidev;
+	int rv;
+
+	iidev = devm_kzalloc(&client->dev, sizeof(*iidev), GFP_KERNEL);
+	if (!iidev)
+		return -ENOMEM;
+
+	if (of_property_read_u8(dev->of_node, "bmcaddr", &iidev->bmcaddr) != 0)
+		iidev->bmcaddr = bmcaddr;
+	if (iidev->bmcaddr == 0 || iidev->bmcaddr & 1) {
+		/* Can't have the write bit set. */
+		dev_notice(&client->dev,
+			   "Invalid bmc address value %2.2x\n", iidev->bmcaddr);
+		return -EINVAL;
+	}
+
+	if (of_property_read_u32(dev->of_node, "retry-time",
+				 &iidev->retry_time_ms) != 0)
+		iidev->retry_time_ms = retry_time_ms;
+
+	if (of_property_read_u32(dev->of_node, "max-retries",
+				 &iidev->max_retries) != 0)
+		iidev->max_retries = max_retries;
+
+	i2c_set_clientdata(client, iidev);
+	client->flags |= I2C_CLIENT_SLAVE;
+
+	rv = i2c_slave_register(client, ipmi_ipmb_slave_cb);
+	if (rv)
+		return rv;
+
+	iidev->client = client;
+
+	iidev->handlers.flags = IPMI_SMI_CAN_HANDLE_IPMB_DIRECT;
+	iidev->handlers.start_processing = ipmi_ipmb_start_processing;
+	iidev->handlers.shutdown = ipmi_ipmb_shutdown;
+	iidev->handlers.sender = ipmi_ipmb_sender;
+	iidev->handlers.request_events = ipmi_ipmb_request_events;
+
+	spin_lock_init(&iidev->lock);
+	sema_init(&iidev->wake_thread, 0);
+	sema_init(&iidev->got_rsp, 0);
+
+	iidev->thread = kthread_run(ipmi_ipmb_thread, iidev,
+				    "kipmb%4.4x", client->addr);
+	if (IS_ERR(iidev->thread)) {
+		rv = PTR_ERR(iidev->thread);
+		dev_notice(&client->dev,
+			   "Could not start kernel thread: error %d\n", rv);
+		goto out_err;
+	}
+
+	rv = ipmi_register_smi(&iidev->handlers,
+			       iidev,
+			       &client->dev,
+			       iidev->bmcaddr);
+	if (rv)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	ipmi_ipmb_remove(client);
+	return rv;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_ipmi_ipmb_match[] = {
+	{ .type = "ipmi", .compatible = DEVICE_NAME },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_ipmi_ipmb_match);
+#else
+#define of_ipmi_ipmb_match NULL
+#endif
+
+static const struct i2c_device_id ipmi_ipmb_id[] = {
+	{ DEVICE_NAME, 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, ipmi_ipmb_id);
+
+static struct i2c_driver ipmi_ipmb_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name = DEVICE_NAME,
+		.of_match_table = of_ipmi_ipmb_match,
+	},
+	.probe		= ipmi_ipmb_probe,
+	.remove		= ipmi_ipmb_remove,
+	.id_table	= ipmi_ipmb_id,
+};
+module_i2c_driver(ipmi_ipmb_driver);
+
+MODULE_AUTHOR("Corey Minyard");
+MODULE_DESCRIPTION("IPMI IPMB driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index e96cb5c4f97a..deed355422f4 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -653,6 +653,11 @@ static int is_ipmb_bcast_addr(struct ipmi_addr *addr)
 	return addr->addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE;
 }
 
+static int is_ipmb_direct_addr(struct ipmi_addr *addr)
+{
+	return addr->addr_type == IPMI_IPMB_DIRECT_ADDR_TYPE;
+}
+
 static void free_recv_msg_list(struct list_head *q)
 {
 	struct ipmi_recv_msg *msg, *msg2;
@@ -805,6 +810,17 @@ ipmi_addr_equal(struct ipmi_addr *addr1, struct ipmi_addr *addr2)
 			&& (ipmb_addr1->lun == ipmb_addr2->lun));
 	}
 
+	if (is_ipmb_direct_addr(addr1)) {
+		struct ipmi_ipmb_direct_addr *daddr1
+			= (struct ipmi_ipmb_direct_addr *) addr1;
+		struct ipmi_ipmb_direct_addr *daddr2
+			= (struct ipmi_ipmb_direct_addr *) addr2;
+
+		return daddr1->slave_addr == daddr2->slave_addr &&
+			daddr1->rq_lun == daddr2->rq_lun &&
+			daddr1->rs_lun == daddr2->rs_lun;
+	}
+
 	if (is_lan_addr(addr1)) {
 		struct ipmi_lan_addr *lan_addr1
 			= (struct ipmi_lan_addr *) addr1;
@@ -843,6 +859,23 @@ int ipmi_validate_addr(struct ipmi_addr *addr, int len)
 		return 0;
 	}
 
+	if (is_ipmb_direct_addr(addr)) {
+		struct ipmi_ipmb_direct_addr *daddr = (void *) addr;
+
+		if (addr->channel != 0)
+			return -EINVAL;
+		if (len < sizeof(struct ipmi_ipmb_direct_addr))
+			return -EINVAL;
+
+		if (daddr->slave_addr & 0x01)
+			return -EINVAL;
+		if (daddr->rq_lun >= 4)
+			return -EINVAL;
+		if (daddr->rs_lun >= 4)
+			return -EINVAL;
+		return 0;
+	}
+
 	if (is_lan_addr(addr)) {
 		if (len < sizeof(struct ipmi_lan_addr))
 			return -EINVAL;
@@ -862,6 +895,9 @@ unsigned int ipmi_addr_length(int addr_type)
 			|| (addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE))
 		return sizeof(struct ipmi_ipmb_addr);
 
+	if (addr_type == IPMI_IPMB_DIRECT_ADDR_TYPE)
+		return sizeof(struct ipmi_ipmb_direct_addr);
+
 	if (addr_type == IPMI_LAN_ADDR_TYPE)
 		return sizeof(struct ipmi_lan_addr);
 
@@ -1710,7 +1746,7 @@ int ipmi_unregister_for_cmd(struct ipmi_user *user,
 }
 EXPORT_SYMBOL(ipmi_unregister_for_cmd);
 
-static unsigned char
+unsigned char
 ipmb_checksum(unsigned char *data, int size)
 {
 	unsigned char csum = 0;
@@ -1720,6 +1756,7 @@ ipmb_checksum(unsigned char *data, int size)
 
 	return -csum;
 }
+EXPORT_SYMBOL(ipmb_checksum);
 
 static inline void format_ipmb_msg(struct ipmi_smi_msg   *smi_msg,
 				   struct kernel_ipmi_msg *msg,
@@ -2051,6 +2088,58 @@ out_err:
 	return rv;
 }
 
+static int i_ipmi_req_ipmb_direct(struct ipmi_smi        *intf,
+				  struct ipmi_addr       *addr,
+				  long			 msgid,
+				  struct kernel_ipmi_msg *msg,
+				  struct ipmi_smi_msg    *smi_msg,
+				  struct ipmi_recv_msg   *recv_msg,
+				  unsigned char          source_lun)
+{
+	struct ipmi_ipmb_direct_addr *daddr;
+	bool is_cmd = !(recv_msg->msg.netfn & 0x1);
+
+	if (!(intf->handlers->flags & IPMI_SMI_CAN_HANDLE_IPMB_DIRECT))
+		return -EAFNOSUPPORT;
+
+	/* Responses must have a completion code. */
+	if (!is_cmd && msg->data_len < 1) {
+		ipmi_inc_stat(intf, sent_invalid_commands);
+		return -EINVAL;
+	}
+
+	if ((msg->data_len + 4) > IPMI_MAX_MSG_LENGTH) {
+		ipmi_inc_stat(intf, sent_invalid_commands);
+		return -EMSGSIZE;
+	}
+
+	daddr = (struct ipmi_ipmb_direct_addr *) addr;
+	if (daddr->rq_lun > 3 || daddr->rs_lun > 3) {
+		ipmi_inc_stat(intf, sent_invalid_commands);
+		return -EINVAL;
+	}
+
+	smi_msg->type = IPMI_SMI_MSG_TYPE_IPMB_DIRECT;
+	smi_msg->msgid = msgid;
+
+	if (is_cmd) {
+		smi_msg->data[0] = msg->netfn << 2 | daddr->rs_lun;
+		smi_msg->data[2] = recv_msg->msgid << 2 | daddr->rq_lun;
+	} else {
+		smi_msg->data[0] = msg->netfn << 2 | daddr->rq_lun;
+		smi_msg->data[2] = recv_msg->msgid << 2 | daddr->rs_lun;
+	}
+	smi_msg->data[1] = daddr->slave_addr;
+	smi_msg->data[3] = msg->cmd;
+
+	memcpy(smi_msg->data + 4, msg->data, msg->data_len);
+	smi_msg->data_size = msg->data_len + 4;
+
+	smi_msg->user_data = recv_msg;
+
+	return 0;
+}
+
 static int i_ipmi_req_lan(struct ipmi_smi        *intf,
 			  struct ipmi_addr       *addr,
 			  long                   msgid,
@@ -2240,6 +2329,9 @@ static int i_ipmi_request(struct ipmi_user     *user,
 		rv = i_ipmi_req_ipmb(intf, addr, msgid, msg, smi_msg, recv_msg,
 				     source_address, source_lun,
 				     retries, retry_time_ms);
+	} else if (is_ipmb_direct_addr(addr)) {
+		rv = i_ipmi_req_ipmb_direct(intf, addr, msgid, msg, smi_msg,
+					    recv_msg, source_lun);
 	} else if (is_lan_addr(addr)) {
 		rv = i_ipmi_req_lan(intf, addr, msgid, msg, smi_msg, recv_msg,
 				    source_lun, retries, retry_time_ms);
@@ -2369,6 +2461,13 @@ static void bmc_device_id_handler(struct ipmi_smi *intf,
 		return;
 	}
 
+	if (msg->msg.data[0]) {
+		dev_warn(intf->si_dev, "device id fetch failed: 0x%2.2x\n",
+			 msg->msg.data[0]);
+		intf->bmc->dyn_id_set = 0;
+		goto out;
+	}
+
 	rv = ipmi_demangle_device_id(msg->msg.netfn, msg->msg.cmd,
 			msg->msg.data, msg->msg.data_len, &intf->bmc->fetch_id);
 	if (rv) {
@@ -2384,7 +2483,7 @@ static void bmc_device_id_handler(struct ipmi_smi *intf,
 		smp_wmb();
 		intf->bmc->dyn_id_set = 1;
 	}
-
+out:
 	wake_up(&intf->waitq);
 }
 
@@ -2617,7 +2716,7 @@ static ssize_t device_id_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 10, "%u\n", id.device_id);
+	return sysfs_emit(buf, "%u\n", id.device_id);
 }
 static DEVICE_ATTR_RO(device_id);
 
@@ -2633,7 +2732,7 @@ static ssize_t provides_device_sdrs_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 10, "%u\n", (id.device_revision & 0x80) >> 7);
+	return sysfs_emit(buf, "%u\n", (id.device_revision & 0x80) >> 7);
 }
 static DEVICE_ATTR_RO(provides_device_sdrs);
 
@@ -2648,7 +2747,7 @@ static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 20, "%u\n", id.device_revision & 0x0F);
+	return sysfs_emit(buf, "%u\n", id.device_revision & 0x0F);
 }
 static DEVICE_ATTR_RO(revision);
 
@@ -2664,7 +2763,7 @@ static ssize_t firmware_revision_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 20, "%u.%x\n", id.firmware_revision_1,
+	return sysfs_emit(buf, "%u.%x\n", id.firmware_revision_1,
 			id.firmware_revision_2);
 }
 static DEVICE_ATTR_RO(firmware_revision);
@@ -2681,7 +2780,7 @@ static ssize_t ipmi_version_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 20, "%u.%u\n",
+	return sysfs_emit(buf, "%u.%u\n",
 			ipmi_version_major(&id),
 			ipmi_version_minor(&id));
 }
@@ -2699,7 +2798,7 @@ static ssize_t add_dev_support_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 10, "0x%02x\n", id.additional_device_support);
+	return sysfs_emit(buf, "0x%02x\n", id.additional_device_support);
 }
 static DEVICE_ATTR(additional_device_support, S_IRUGO, add_dev_support_show,
 		   NULL);
@@ -2716,7 +2815,7 @@ static ssize_t manufacturer_id_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 20, "0x%6.6x\n", id.manufacturer_id);
+	return sysfs_emit(buf, "0x%6.6x\n", id.manufacturer_id);
 }
 static DEVICE_ATTR_RO(manufacturer_id);
 
@@ -2732,7 +2831,7 @@ static ssize_t product_id_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 10, "0x%4.4x\n", id.product_id);
+	return sysfs_emit(buf, "0x%4.4x\n", id.product_id);
 }
 static DEVICE_ATTR_RO(product_id);
 
@@ -2748,7 +2847,7 @@ static ssize_t aux_firmware_rev_show(struct device *dev,
 	if (rv)
 		return rv;
 
-	return snprintf(buf, 21, "0x%02x 0x%02x 0x%02x 0x%02x\n",
+	return sysfs_emit(buf, "0x%02x 0x%02x 0x%02x 0x%02x\n",
 			id.aux_firmware_revision[3],
 			id.aux_firmware_revision[2],
 			id.aux_firmware_revision[1],
@@ -2770,7 +2869,7 @@ static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
 	if (!guid_set)
 		return -ENOENT;
 
-	return snprintf(buf, UUID_STRING_LEN + 1 + 1, "%pUl\n", &guid);
+	return sysfs_emit(buf, "%pUl\n", &guid);
 }
 static DEVICE_ATTR_RO(guid);
 
@@ -3794,6 +3893,123 @@ static int handle_ipmb_get_msg_cmd(struct ipmi_smi *intf,
 	return rv;
 }
 
+static int handle_ipmb_direct_rcv_cmd(struct ipmi_smi *intf,
+				      struct ipmi_smi_msg *msg)
+{
+	struct cmd_rcvr          *rcvr;
+	int                      rv = 0;
+	struct ipmi_user         *user = NULL;
+	struct ipmi_ipmb_direct_addr *daddr;
+	struct ipmi_recv_msg     *recv_msg;
+	unsigned char netfn = msg->rsp[0] >> 2;
+	unsigned char cmd = msg->rsp[3];
+
+	rcu_read_lock();
+	/* We always use channel 0 for direct messages. */
+	rcvr = find_cmd_rcvr(intf, netfn, cmd, 0);
+	if (rcvr) {
+		user = rcvr->user;
+		kref_get(&user->refcount);
+	} else
+		user = NULL;
+	rcu_read_unlock();
+
+	if (user == NULL) {
+		/* We didn't find a user, deliver an error response. */
+		ipmi_inc_stat(intf, unhandled_commands);
+
+		msg->data[0] = ((netfn + 1) << 2) | (msg->rsp[4] & 0x3);
+		msg->data[1] = msg->rsp[2];
+		msg->data[2] = msg->rsp[4] & ~0x3;
+		msg->data[3] = cmd;
+		msg->data[4] = IPMI_INVALID_CMD_COMPLETION_CODE;
+		msg->data_size = 5;
+
+		rcu_read_lock();
+		if (!intf->in_shutdown) {
+			smi_send(intf, intf->handlers, msg, 0);
+			/*
+			 * We used the message, so return the value
+			 * that causes it to not be freed or
+			 * queued.
+			 */
+			rv = -1;
+		}
+		rcu_read_unlock();
+	} else {
+		recv_msg = ipmi_alloc_recv_msg();
+		if (!recv_msg) {
+			/*
+			 * We couldn't allocate memory for the
+			 * message, so requeue it for handling
+			 * later.
+			 */
+			rv = 1;
+			kref_put(&user->refcount, free_user);
+		} else {
+			/* Extract the source address from the data. */
+			daddr = (struct ipmi_ipmb_direct_addr *)&recv_msg->addr;
+			daddr->addr_type = IPMI_IPMB_DIRECT_ADDR_TYPE;
+			daddr->channel = 0;
+			daddr->slave_addr = msg->rsp[1];
+			daddr->rs_lun = msg->rsp[0] & 3;
+			daddr->rq_lun = msg->rsp[2] & 3;
+
+			/*
+			 * Extract the rest of the message information
+			 * from the IPMB header.
+			 */
+			recv_msg->user = user;
+			recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
+			recv_msg->msgid = (msg->rsp[2] >> 2);
+			recv_msg->msg.netfn = msg->rsp[0] >> 2;
+			recv_msg->msg.cmd = msg->rsp[3];
+			recv_msg->msg.data = recv_msg->msg_data;
+
+			recv_msg->msg.data_len = msg->rsp_size - 4;
+			memcpy(recv_msg->msg_data, msg->rsp + 4,
+			       msg->rsp_size - 4);
+			if (deliver_response(intf, recv_msg))
+				ipmi_inc_stat(intf, unhandled_commands);
+			else
+				ipmi_inc_stat(intf, handled_commands);
+		}
+	}
+
+	return rv;
+}
+
+static int handle_ipmb_direct_rcv_rsp(struct ipmi_smi *intf,
+				      struct ipmi_smi_msg *msg)
+{
+	struct ipmi_recv_msg *recv_msg;
+	struct ipmi_ipmb_direct_addr *daddr;
+
+	recv_msg = (struct ipmi_recv_msg *) msg->user_data;
+	if (recv_msg == NULL) {
+		dev_warn(intf->si_dev,
+			 "IPMI message received with no owner. This could be because of a malformed message, or because of a hardware error.  Contact your hardware vendor for assistance.\n");
+		return 0;
+	}
+
+	recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
+	recv_msg->msgid = msg->msgid;
+	daddr = (struct ipmi_ipmb_direct_addr *) &recv_msg->addr;
+	daddr->addr_type = IPMI_IPMB_DIRECT_ADDR_TYPE;
+	daddr->channel = 0;
+	daddr->slave_addr = msg->rsp[1];
+	daddr->rq_lun = msg->rsp[0] & 3;
+	daddr->rs_lun = msg->rsp[2] & 3;
+	recv_msg->msg.netfn = msg->rsp[0] >> 2;
+	recv_msg->msg.cmd = msg->rsp[3];
+	memcpy(recv_msg->msg_data, &msg->rsp[4], msg->rsp_size - 4);
+	recv_msg->msg.data = recv_msg->msg_data;
+	recv_msg->msg.data_len = msg->rsp_size - 4;
+	deliver_local_response(intf, recv_msg);
+
+	return 0;
+}
+
 static int handle_lan_get_msg_rsp(struct ipmi_smi *intf,
 				  struct ipmi_smi_msg *msg)
 {
@@ -4219,18 +4435,40 @@ static int handle_bmc_rsp(struct ipmi_smi *intf,
 static int handle_one_recv_msg(struct ipmi_smi *intf,
 			       struct ipmi_smi_msg *msg)
 {
-	int requeue;
+	int requeue = 0;
 	int chan;
+	unsigned char cc;
+	bool is_cmd = !((msg->rsp[0] >> 2) & 1);
 
 	pr_debug("Recv: %*ph\n", msg->rsp_size, msg->rsp);
 
-	if ((msg->data_size >= 2)
+	if (msg->rsp_size < 2) {
+		/* Message is too small to be correct. */
+		dev_warn(intf->si_dev,
+			 "BMC returned too small a message for netfn %x cmd %x, got %d bytes\n",
+			 (msg->data[0] >> 2) | 1, msg->data[1], msg->rsp_size);
+
+return_unspecified:
+		/* Generate an error response for the message. */
+		msg->rsp[0] = msg->data[0] | (1 << 2);
+		msg->rsp[1] = msg->data[1];
+		msg->rsp[2] = IPMI_ERR_UNSPECIFIED;
+		msg->rsp_size = 3;
+	} else if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+		/* commands must have at least 3 bytes, responses 4. */
+		if (is_cmd && (msg->rsp_size < 3)) {
+			ipmi_inc_stat(intf, invalid_commands);
+			goto out;
+		}
+		if (!is_cmd && (msg->rsp_size < 4))
+			goto return_unspecified;
+	} else if ((msg->data_size >= 2)
 	    && (msg->data[0] == (IPMI_NETFN_APP_REQUEST << 2))
 	    && (msg->data[1] == IPMI_SEND_MSG_CMD)
 	    && (msg->user_data == NULL)) {
 
 		if (intf->in_shutdown)
-			goto free_msg;
+			goto out;
 
 		/*
 		 * This is the local response to a command send, start
@@ -4265,21 +4503,6 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
 		} else
 			/* The message was sent, start the timer. */
 			intf_start_seq_timer(intf, msg->msgid);
-free_msg:
-		requeue = 0;
-		goto out;
-
-	} else if (msg->rsp_size < 2) {
-		/* Message is too small to be correct. */
-		dev_warn(intf->si_dev,
-			 "BMC returned too small a message for netfn %x cmd %x, got %d bytes\n",
-			 (msg->data[0] >> 2) | 1, msg->data[1], msg->rsp_size);
-
-		/* Generate an error response for the message. */
-		msg->rsp[0] = msg->data[0] | (1 << 2);
-		msg->rsp[1] = msg->data[1];
-		msg->rsp[2] = IPMI_ERR_UNSPECIFIED;
-		msg->rsp_size = 3;
 	} else if (((msg->rsp[0] >> 2) != ((msg->data[0] >> 2) | 1))
 		   || (msg->rsp[1] != msg->data[1])) {
 		/*
@@ -4291,39 +4514,46 @@ free_msg:
 			 (msg->data[0] >> 2) | 1, msg->data[1],
 			 msg->rsp[0] >> 2, msg->rsp[1]);
 
-		/* Generate an error response for the message. */
-		msg->rsp[0] = msg->data[0] | (1 << 2);
-		msg->rsp[1] = msg->data[1];
-		msg->rsp[2] = IPMI_ERR_UNSPECIFIED;
-		msg->rsp_size = 3;
+		goto return_unspecified;
 	}
 
-	if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
-	    && (msg->rsp[1] == IPMI_SEND_MSG_CMD)
-	    && (msg->user_data != NULL)) {
+	if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+		if ((msg->data[0] >> 2) & 1) {
+			/* It's a response to a sent response. */
+			chan = 0;
+			cc = msg->rsp[4];
+			goto process_response_response;
+		}
+		if (is_cmd)
+			requeue = handle_ipmb_direct_rcv_cmd(intf, msg);
+		else
+			requeue = handle_ipmb_direct_rcv_rsp(intf, msg);
+	} else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
+		   && (msg->rsp[1] == IPMI_SEND_MSG_CMD)
+		   && (msg->user_data != NULL)) {
 		/*
 		 * It's a response to a response we sent.  For this we
 		 * deliver a send message response to the user.
 		 */
-		struct ipmi_recv_msg *recv_msg = msg->user_data;
-
-		requeue = 0;
-		if (msg->rsp_size < 2)
-			/* Message is too small to be correct. */
-			goto out;
+		struct ipmi_recv_msg *recv_msg;
 
 		chan = msg->data[2] & 0x0f;
 		if (chan >= IPMI_MAX_CHANNELS)
 			/* Invalid channel number */
 			goto out;
+		cc = msg->rsp[2];
 
+process_response_response:
+		recv_msg = msg->user_data;
+
+		requeue = 0;
 		if (!recv_msg)
 			goto out;
 
 		recv_msg->recv_type = IPMI_RESPONSE_RESPONSE_TYPE;
 		recv_msg->msg.data = recv_msg->msg_data;
+		recv_msg->msg_data[0] = cc;
 		recv_msg->msg.data_len = 1;
-		recv_msg->msg_data[0] = msg->rsp[2];
 		deliver_local_response(intf, recv_msg);
 	} else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
 		   && (msg->rsp[1] == IPMI_GET_MSG_CMD)) {
@@ -4789,7 +5019,9 @@ static atomic_t recv_msg_inuse_count = ATOMIC_INIT(0);
 static void free_smi_msg(struct ipmi_smi_msg *msg)
 {
 	atomic_dec(&smi_msg_inuse_count);
-	kfree(msg);
+	/* Try to keep as much stuff out of the panic path as possible. */
+	if (!oops_in_progress)
+		kfree(msg);
 }
 
 struct ipmi_smi_msg *ipmi_alloc_smi_msg(void)
@@ -4808,7 +5040,9 @@ EXPORT_SYMBOL(ipmi_alloc_smi_msg);
 static void free_recv_msg(struct ipmi_recv_msg *msg)
 {
 	atomic_dec(&recv_msg_inuse_count);
-	kfree(msg);
+	/* Try to keep as much stuff out of the panic path as possible. */
+	if (!oops_in_progress)
+		kfree(msg);
 }
 
 static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void)
@@ -4826,7 +5060,7 @@ static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void)
 
 void ipmi_free_recv_msg(struct ipmi_recv_msg *msg)
 {
-	if (msg->user)
+	if (msg->user && !oops_in_progress)
 		kref_put(&msg->user->refcount, free_user);
 	msg->done(msg);
 }
diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 6f3272b58ced..64dedb3ef8ec 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -1603,7 +1603,7 @@ static ssize_t name##_show(struct device *dev,			\
 {									\
 	struct smi_info *smi_info = dev_get_drvdata(dev);		\
 									\
-	return snprintf(buf, 10, "%u\n", smi_get_stat(smi_info, name));	\
+	return sysfs_emit(buf, "%u\n", smi_get_stat(smi_info, name));	\
 }									\
 static DEVICE_ATTR_RO(name)
 
@@ -1613,7 +1613,7 @@ static ssize_t type_show(struct device *dev,
 {
 	struct smi_info *smi_info = dev_get_drvdata(dev);
 
-	return snprintf(buf, 10, "%s\n", si_to_str[smi_info->io.si_type]);
+	return sysfs_emit(buf, "%s\n", si_to_str[smi_info->io.si_type]);
 }
 static DEVICE_ATTR_RO(type);
 
@@ -1624,7 +1624,7 @@ static ssize_t interrupts_enabled_show(struct device *dev,
 	struct smi_info *smi_info = dev_get_drvdata(dev);
 	int enabled = smi_info->io.irq && !smi_info->interrupt_disabled;
 
-	return snprintf(buf, 10, "%d\n", enabled);
+	return sysfs_emit(buf, "%d\n", enabled);
 }
 static DEVICE_ATTR_RO(interrupts_enabled);
 
@@ -1646,7 +1646,7 @@ static ssize_t params_show(struct device *dev,
 {
 	struct smi_info *smi_info = dev_get_drvdata(dev);
 
-	return snprintf(buf, 200,
+	return sysfs_emit(buf,
 			"%s,%s,0x%lx,rsp=%d,rsi=%d,rsh=%d,irq=%d,ipmb=%d\n",
 			si_to_str[smi_info->io.si_type],
 			addr_space_to_str[smi_info->io.addr_space],
diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 20d5af92966d..0c62e578749e 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1190,7 +1190,7 @@ static ssize_t ipmi_##name##_show(struct device *dev,			\
 {									\
 	struct ssif_info *ssif_info = dev_get_drvdata(dev);		\
 									\
-	return snprintf(buf, 10, "%u\n", ssif_get_stat(ssif_info, name));\
+	return sysfs_emit(buf, "%u\n", ssif_get_stat(ssif_info, name));\
 }									\
 static DEVICE_ATTR(name, S_IRUGO, ipmi_##name##_show, NULL)
 
@@ -1198,7 +1198,7 @@ static ssize_t ipmi_type_show(struct device *dev,
 			      struct device_attribute *attr,
 			      char *buf)
 {
-	return snprintf(buf, 10, "ssif\n");
+	return sysfs_emit(buf, "ssif\n");
 }
 static DEVICE_ATTR(type, S_IRUGO, ipmi_type_show, NULL);
 
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index e4ff3b50de7f..883b4a341012 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -342,13 +342,17 @@ static atomic_t msg_tofree = ATOMIC_INIT(0);
 static DECLARE_COMPLETION(msg_wait);
 static void msg_free_smi(struct ipmi_smi_msg *msg)
 {
-	if (atomic_dec_and_test(&msg_tofree))
-		complete(&msg_wait);
+	if (atomic_dec_and_test(&msg_tofree)) {
+		if (!oops_in_progress)
+			complete(&msg_wait);
+	}
 }
 static void msg_free_recv(struct ipmi_recv_msg *msg)
 {
-	if (atomic_dec_and_test(&msg_tofree))
-		complete(&msg_wait);
+	if (atomic_dec_and_test(&msg_tofree)) {
+		if (!oops_in_progress)
+			complete(&msg_wait);
+	}
 }
 static struct ipmi_smi_msg smi_msg = {
 	.done = msg_free_smi
@@ -434,8 +438,10 @@ static int _ipmi_set_timeout(int do_heartbeat)
 	rv = __ipmi_set_timeout(&smi_msg,
 				&recv_msg,
 				&send_heartbeat_now);
-	if (rv)
+	if (rv) {
+		atomic_set(&msg_tofree, 0);
 		return rv;
+	}
 
 	wait_for_completion(&msg_wait);
 
@@ -497,7 +503,7 @@ static void panic_halt_ipmi_heartbeat(void)
 	msg.cmd = IPMI_WDOG_RESET_TIMER;
 	msg.data = NULL;
 	msg.data_len = 0;
-	atomic_inc(&panic_done_count);
+	atomic_add(2, &panic_done_count);
 	rv = ipmi_request_supply_msgs(watchdog_user,
 				      (struct ipmi_addr *) &addr,
 				      0,
@@ -507,7 +513,7 @@ static void panic_halt_ipmi_heartbeat(void)
 				      &panic_halt_heartbeat_recv_msg,
 				      1);
 	if (rv)
-		atomic_dec(&panic_done_count);
+		atomic_sub(2, &panic_done_count);
 }
 
 static struct ipmi_smi_msg panic_halt_smi_msg = {
@@ -531,12 +537,12 @@ static void panic_halt_ipmi_set_timeout(void)
 	/* Wait for the messages to be free. */
 	while (atomic_read(&panic_done_count) != 0)
 		ipmi_poll_interface(watchdog_user);
-	atomic_inc(&panic_done_count);
+	atomic_add(2, &panic_done_count);
 	rv = __ipmi_set_timeout(&panic_halt_smi_msg,
 				&panic_halt_recv_msg,
 				&send_heartbeat_now);
 	if (rv) {
-		atomic_dec(&panic_done_count);
+		atomic_sub(2, &panic_done_count);
 		pr_warn("Unable to extend the watchdog timeout\n");
 	} else {
 		if (send_heartbeat_now)
@@ -580,6 +586,7 @@ restart:
 				      &recv_msg,
 				      1);
 	if (rv) {
+		atomic_set(&msg_tofree, 0);
 		pr_warn("heartbeat send failure: %d\n", rv);
 		return rv;
 	}
diff --git a/drivers/char/ipmi/kcs_bmc_serio.c b/drivers/char/ipmi/kcs_bmc_serio.c
index 7948cabde50b..7e2067628a6c 100644
--- a/drivers/char/ipmi/kcs_bmc_serio.c
+++ b/drivers/char/ipmi/kcs_bmc_serio.c
@@ -73,10 +73,12 @@ static int kcs_bmc_serio_add_device(struct kcs_bmc_device *kcs_bmc)
 	struct serio *port;
 
 	priv = devm_kzalloc(kcs_bmc->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
 
 	/* Use kzalloc() as the allocation is cleaned up with kfree() via serio_unregister_port() */
 	port = kzalloc(sizeof(*port), GFP_KERNEL);
-	if (!(priv && port))
+	if (!port)
 		return -ENOMEM;
 
 	port->id.type = SERIO_8042;
diff --git a/include/linux/ipmi.h b/include/linux/ipmi.h
index 52850a02a3d0..163831a087ef 100644
--- a/include/linux/ipmi.h
+++ b/include/linux/ipmi.h
@@ -335,4 +335,7 @@ extern int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data);
 
 #define GET_DEVICE_ID_MAX_RETRY		5
 
+/* Helper function for computing the IPMB checksum of some data. */
+unsigned char ipmb_checksum(unsigned char *data, int size);
+
 #endif /* __LINUX_IPMI_H */
diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h
index deec18b8944a..9277d21c2690 100644
--- a/include/linux/ipmi_smi.h
+++ b/include/linux/ipmi_smi.h
@@ -38,6 +38,59 @@ struct ipmi_smi;
 #define IPMI_WATCH_MASK_CHECK_WATCHDOG	(1 << 1)
 #define IPMI_WATCH_MASK_CHECK_COMMANDS	(1 << 2)
 
+/*
+ * SMI messages
+ *
+ * When communicating with an SMI, messages come in two formats:
+ *
+ * * Normal (to a BMC over a BMC interface)
+ *
+ * * IPMB (over a IPMB to another MC)
+ *
+ * When normal, commands are sent using the format defined by a
+ * standard message over KCS (NetFn must be even):
+ *
+ *   +-----------+-----+------+
+ *   | NetFn/LUN | Cmd | Data |
+ *   +-----------+-----+------+
+ *
+ * And responses, similarly, with an completion code added (NetFn must
+ * be odd):
+ *
+ *   +-----------+-----+------+------+
+ *   | NetFn/LUN | Cmd | CC   | Data |
+ *   +-----------+-----+------+------+
+ *
+ * With normal messages, only commands are sent and only responses are
+ * received.
+ *
+ * In IPMB mode, we are acting as an IPMB device. Commands will be in
+ * the following format (NetFn must be even):
+ *
+ *   +-------------+------+-------------+-----+------+
+ *   | NetFn/rsLUN | Addr | rqSeq/rqLUN | Cmd | Data |
+ *   +-------------+------+-------------+-----+------+
+ *
+ * Responses will using the following format:
+ *
+ *   +-------------+------+-------------+-----+------+------+
+ *   | NetFn/rqLUN | Addr | rqSeq/rsLUN | Cmd | CC   | Data |
+ *   +-------------+------+-------------+-----+------+------+
+ *
+ * This is similar to the format defined in the IPMB manual section
+ * 2.11.1 with the checksums and the first address removed.  Also, the
+ * address is always the remote address.
+ *
+ * IPMB messages can be commands and responses in both directions.
+ * Received commands are handled as received commands from the message
+ * queue.
+ */
+
+enum ipmi_smi_msg_type {
+	IPMI_SMI_MSG_TYPE_NORMAL = 0,
+	IPMI_SMI_MSG_TYPE_IPMB_DIRECT
+};
+
 /*
  * Messages to/from the lower layer.  The smi interface will take one
  * of these to send. After the send has occurred and a response has
@@ -54,6 +107,8 @@ struct ipmi_smi;
 struct ipmi_smi_msg {
 	struct list_head link;
 
+	enum ipmi_smi_msg_type type;
+
 	long    msgid;
 	void    *user_data;
 
@@ -73,6 +128,10 @@ struct ipmi_smi_msg {
 struct ipmi_smi_handlers {
 	struct module *owner;
 
+	/* Capabilities of the SMI. */
+#define IPMI_SMI_CAN_HANDLE_IPMB_DIRECT		(1 << 0)
+	unsigned int flags;
+
 	/*
 	 * The low-level interface cannot start sending messages to
 	 * the upper layer until this function is called.  This may
diff --git a/include/uapi/linux/ipmi.h b/include/uapi/linux/ipmi.h
index 32d148309b16..966c3070959b 100644
--- a/include/uapi/linux/ipmi.h
+++ b/include/uapi/linux/ipmi.h
@@ -80,6 +80,20 @@ struct ipmi_ipmb_addr {
 	unsigned char lun;
 };
 
+/*
+ * Used for messages received directly from an IPMB that have not gone
+ * through a MC.  This is for systems that sit right on an IPMB so
+ * they can receive commands and respond to them.
+ */
+#define IPMI_IPMB_DIRECT_ADDR_TYPE	0x81
+struct ipmi_ipmb_direct_addr {
+	int           addr_type;
+	short         channel;
+	unsigned char slave_addr;
+	unsigned char rs_lun;
+	unsigned char rq_lun;
+};
+
 /*
  * A LAN Address.  This is an address to/from a LAN interface bridged
  * by the BMC, not an address actually out on the LAN.
@@ -158,7 +172,7 @@ struct kernel_ipmi_msg {
  * is used for the receive in-kernel interface and in the receive
  * IOCTL.
  *
- * The "IPMI_RESPONSE_RESPNOSE_TYPE" is a little strange sounding, but
+ * The "IPMI_RESPONSE_RESPONSE_TYPE" is a little strange sounding, but
  * it allows you to get the message results when you send a response
  * message.
  */