diff --git a/arch/powerpc/include/asm/io_event_irq.h b/arch/powerpc/include/asm/io_event_irq.h
new file mode 100644
index 0000000..cbaef02
--- /dev/null
+++ b/arch/powerpc/include/asm/io_event_irq.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2010, 2011 Mark Nelson and Tseng-Hui (Frank) Lin, 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 _ASM_POWERPC_IO_EVENT_IRQ_H
+#define _ASM_POWERPC_IO_EVENT_IRQ_H
+
+#include <linux/types.h>
+#include <linux/notifier.h>
+
+#define PSERIES_IOEI_RPC_MAX_LEN 216
+
+#define PSERIES_IOEI_TYPE_ERR_DETECTED		0x01
+#define PSERIES_IOEI_TYPE_ERR_RECOVERED		0x02
+#define PSERIES_IOEI_TYPE_EVENT			0x03
+#define PSERIES_IOEI_TYPE_RPC_PASS_THRU		0x04
+
+#define PSERIES_IOEI_SUBTYPE_NOT_APP		0x00
+#define PSERIES_IOEI_SUBTYPE_REBALANCE_REQ	0x01
+#define PSERIES_IOEI_SUBTYPE_NODE_ONLINE	0x03
+#define PSERIES_IOEI_SUBTYPE_NODE_OFFLINE	0x04
+#define PSERIES_IOEI_SUBTYPE_DUMP_SIZE_CHANGE	0x05
+#define PSERIES_IOEI_SUBTYPE_TORRENT_IRV_UPDATE	0x06
+#define PSERIES_IOEI_SUBTYPE_TORRENT_HFI_CFGED	0x07
+
+#define PSERIES_IOEI_SCOPE_NOT_APP		0x00
+#define PSERIES_IOEI_SCOPE_RIO_HUB		0x36
+#define PSERIES_IOEI_SCOPE_RIO_BRIDGE		0x37
+#define PSERIES_IOEI_SCOPE_PHB			0x38
+#define PSERIES_IOEI_SCOPE_EADS_GLOBAL		0x39
+#define PSERIES_IOEI_SCOPE_EADS_SLOT		0x3A
+#define PSERIES_IOEI_SCOPE_TORRENT_HUB		0x3B
+#define PSERIES_IOEI_SCOPE_SERVICE_PROC		0x51
+
+/* Platform Event Log Format, Version 6, data portition of IO event section */
+struct pseries_io_event_sect_data {
+	uint8_t event_type;		/* 0x00 IO-Event Type		*/
+	uint8_t rpc_data_len;		/* 0x01 RPC data length		*/
+	uint8_t scope;			/* 0x02 Error/Event Scope	*/
+	uint8_t event_subtype;		/* 0x03 I/O-Event Sub-Type	*/
+	uint32_t drc_index;		/* 0x04 DRC Index		*/
+	uint8_t rpc_data[PSERIES_IOEI_RPC_MAX_LEN];
+					/* 0x08 RPC Data (0-216 bytes,	*/
+					/* padded to 4 bytes alignment)	*/
+};
+
+extern struct atomic_notifier_head pseries_ioei_notifier_list;
+
+#endif /* _ASM_POWERPC_IO_EVENT_IRQ_H */
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index 5b3da4b..d44af70 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -52,6 +52,25 @@ 	bool
	depends on PPC_PSERIES && RTAS_ERROR_LOGGING
	default n

+config IO_EVENT_IRQ
+	bool "IO Event Interrupt support"
+	depends on PPC_PSERIES
+	select PSERIES_EVENT_LOG
+	default y
+	help
+	  Select this option, if you want to enable support for IO Event
+	  interrupts. IO event interrupt is a mechanism provided by RTAS
+	  to return information about hardware error and non-error events
+	  which may need OS attention. RTAS returns events for multiple
+	  event types and scopes. Device drivers can register their handlers
+	  to receive events.
+
+	  This option will only enable the IO event platform code. You
+	  will still need to enable or compile the actual drivers
+	  that use this infrastruture to handle IO event interrupts.
+
+	  Say Y if you are unsure.
+
 config LPARCFG
 	bool "LPAR Configuration Data"
 	depends on PPC_PSERIES || PPC_ISERIES
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index fc52378..5070a45 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_PHYP_DUMP)		+= phyp_dump.o
 obj-$(CONFIG_CMM)		+= cmm.o
 obj-$(CONFIG_DTL)		+= dtl.o
 obj-$(CONFIG_PSERIES_EVENT_LOG)	+= pseries_event_log.o
+obj-$(CONFIG_IO_EVENT_IRQ)	+= io_event_irq.o
 
 ifeq ($(CONFIG_PPC_PSERIES),y)
 obj-$(CONFIG_SUSPEND)		+= suspend.o
diff --git a/arch/powerpc/platforms/pseries/io_event_irq.c b/arch/powerpc/platforms/pseries/io_event_irq.c
new file mode 100644
index 0000000..7d963b5
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/io_event_irq.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright 2010 2011 Mark Nelson and Tseng-Hui (Frank) Lin, 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/errno.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/list.h>
+#include <linux/notifier.h>
+
+#include <asm/machdep.h>
+#include <asm/rtas.h>
+#include <asm/irq.h>
+#include <asm/io_event_irq.h>
+
+#include "pseries.h"
+#include "pseries_event_log.h"
+
+/*
+ * IO event interrupt is a mechanism provided by RTAS to return
+ * information about hardware error and non-error events. Device
+ * drivers can register their event handlers to receive events.
+ * Device drivers are expected to use atomic_notifier_chain_register()
+ * and atomic_notifier_chain_unregister() to register and unregister
+ * their event handlers. Since multiple IO event types and scopes
+ * share an IO event interrupt, the event handlers are called one
+ * by one until the IO event is claimed by one of the handlers.
+ * The event handlers are expected to return NOTIFY_OK if the
+ * event is handled by the event handler or NOTIFY_DONE if the
+ * event does not belong to the handler.
+ *
+ * Usage:
+ *
+ * Notifier function:
+ * #include <asm/io_event_irq.h>
+ * int event_handler(struct notifier_block *nb, unsigned long val, void *data) {
+ * 	p = (struct pseries_io_event_sect_data *) data;
+ * 	if (! is_my_event(p->scope, p->event_type)) return NOTIFY_DONE;
+ * 		:
+ * 		:
+ * 	return NOTIFY_OK;
+ * }
+ * struct notifier_block event_nb = {
+ * 	.notifier_call = event_handler;
+ * }
+ *
+ * Registration:
+ * atomic_notifier_chain_register(&pseries_ioei_notifier_list, &event_nb);
+ *
+ * Unregistration:
+ * atomic_notifier_chain_unregister(&pseries_ioei_notifier_list, &event_nb);
+ */
+
+ATOMIC_NOTIFIER_HEAD(pseries_ioei_notifier_list);
+EXPORT_SYMBOL_GPL(pseries_ioei_notifier_list);
+
+static int ioei_supported = 0;
+
+static int ioei_check_exception_token;
+
+/*
+ * Find the data portion of an IO Event section from event log.
+ * Return:
+ * 	pointer to a valid IO event section data. NULL if not found.
+ */
+static struct pseries_io_event_sect_data *
+		ioei_find_event(struct rtas_error_log *rtas_elog)
+{
+	struct pseries_io_event_sect_data *event_p;
+
+	/* We should only ever get called for io-event interrupts, but if
+	 * we do get called for another type then something went wrong so
+	 * make some noise about it.
+	 * RTAS_TYPE_IO only exists in extended event log version 6 or later.
+	 * No need to check event log version.
+	 */
+	if (unlikely(rtas_elog->type != RTAS_TYPE_IO)) {
+		pr_warning("io_event_irq: We got called with an event type "
+			   "of %d rather than %d!\n",
+			   rtas_elog->type, RTAS_TYPE_IO);
+		WARN_ON(1);
+		return NULL;
+	}
+
+	event_p = pseries_elog_find_sect_data(
+			(struct rtas_ext_event_log_v6 *) &rtas_elog->buffer,
+			rtas_elog->extended_log_length,
+			PSERIES_ELOG_SECT_ID_IO_EVENT);
+	if (unlikely(!event_p)) {
+		pr_warning("io_event_irq: RTAS extended event log does not "
+			   "contain an IO Event section. Could be a bug in "
+			   "system firmware!\n");
+		WARN_ON(1);
+		return NULL;
+	}
+	return event_p;
+}
+
+/*
+ * PAPR:
+ * - check-exception returns the first found error or event and clear that
+ *   error or event so it is reported once.
+ * - Each interrupt returns one event. If a plateform chooses to report
+ *   multiple events through a single interrupt, it must ensure that the
+ *   interrupt remains asserted until check-exception has been used to
+ *   process all out-standing events for that interrupt.
+ *
+ * Implementation notes:
+ * - Events must be processed in the order they are returned. Hence,
+ *   sequential in nature.
+ * - The owner of an event is determined by combinations of scope,
+ *   event type, and sub-type. There is no easy way to pre-sort clients
+ *   by scope or event type alone. For example, Torrent ISR route change
+ *   event is reported with scope 0x00 (Not Applicatable) rather than
+ *   0x3B (Torrent-hub). It is better to let the clients to identify
+ *   who owns the the event.
+ */
+
+static irqreturn_t ioei_interrupt(int irq, void *dev_id)
+{
+	struct pseries_io_event_sect_data *ioei_buf, *event_p;
+	int rtas_status, notifier_status;
+
+	ioei_buf = kmalloc(sizeof(struct pseries_io_event_sect_data),
+			     GFP_KERNEL);
+	/* Do not check kmalloc() return code here. We need to call	*/
+	/* rtas_call() to release interrupt even if kmalloc() failed.	*/
+	do {
+		spin_lock(&rtas_data_buf_lock);
+		rtas_status = rtas_call(ioei_check_exception_token, 6, 1, NULL,
+					RTAS_VECTOR_EXTERNAL_INTERRUPT,
+					virq_to_hw(irq),
+					RTAS_IO_EVENTS, 1 /* Time Critical */,
+					__pa(&rtas_data_buf),
+					RTAS_DATA_BUF_SIZE);
+		if (rtas_status == 0)
+			event_p = ioei_find_event((struct rtas_error_log *)
+						  &rtas_data_buf);
+		else
+			event_p = NULL;
+		if (event_p) {
+			if (ioei_buf)
+				memcpy(ioei_buf, event_p,
+				       pseries_elog_sect_data_len(event_p));
+			else
+				pr_warning("io_event_irq: No memory to copy "
+					   "IO event. Event type=%d, scope=%d. "
+					   "Interrupt lost!\n",
+					   event_p->event_type, event_p->scope);
+		}
+		spin_unlock(&rtas_data_buf_lock);
+		if (event_p) {
+			notifier_status = atomic_notifier_call_chain(
+						&pseries_ioei_notifier_list,
+						0, ioei_buf);
+			if (notifier_status == NOTIFY_DONE)
+				pr_warning("io_event_irq: No one claims "
+					   "interrupt for IO event type=%d, "
+					   "scope=%d. Interrupt lost!\n",
+					   ioei_buf->event_type,
+					   ioei_buf->scope);
+		}
+	} while (rtas_status == 0);
+
+	if (ioei_buf)
+		kfree(ioei_buf);
+	return IRQ_HANDLED;
+}
+
+static int __init pseries_ioei_init_irq(void)
+{
+	struct device_node *np;
+
+	ioei_supported = 0;
+	ioei_check_exception_token = rtas_token("check-exception");
+	if (ioei_check_exception_token == RTAS_UNKNOWN_SERVICE) {
+		pr_warning("io_event_irq: No check-exception on system! "
+			   "IO Event interrupt disabled.\n");
+		return -ENODEV;
+	}
+
+	np = of_find_node_by_path("/event-sources/ibm,io-events");
+	if (np) {
+		request_event_sources_irqs(np, ioei_interrupt, "IO_EVENT");
+		of_node_put(np);
+	} else {
+		pr_warning("io_event_irq: No ibm,io-events on system! "
+			   "IO Event interrupt disabled.\n");
+		return -ENODEV;
+	}
+
+	ioei_supported = 1;
+
+	return 0;
+}
+
+machine_device_initcall(pseries, pseries_ioei_init_irq);
+
