diff mbox series

[22/24] irqchip/gic-v5: Add GICv5 ITS support

Message ID 20250408-gicv5-host-v1-22-1f26db465f8d@kernel.org (mailing list archive)
State New
Headers show
Series Arm GICv5: Host driver implementation | expand

Commit Message

Lorenzo Pieralisi April 8, 2025, 10:50 a.m. UTC
The GICv5 architecture implements Interrupt Translation Service
(ITS) components in order to translate events coming from peripherals
into interrupt events delivered to the connected IRSes.

Events (ie MSI memory writes to ITS translate frame), are translated
by the ITS using tables kept in memory.

ITS translation tables for peripherals is kept in memory storage
(device table [DT] and Interrupt Translation Table [ITT]) that
is allocated by the driver on boot.

Both tables can be 1- or 2-level; the structure is chosen by the
driver after probing the ITS HW parameters and checking the
allowed table splits and supported {device/event}_IDbits.

DT table entries are allocated on demand (ie when a device is
probed); the DT table is sized using the number of supported
deviceID bits in that that's a system design decision (ie the
number of deviceID bits implemented should reflect the number
of devices expected in a system) therefore it makes sense to
allocate a DT table that can cater for the maximum number of
devices.

DT and ITT tables are allocated using the kmalloc interface;
the allocation size may be smaller than a page or larger,
and must provide contiguous memory pages.

LPIs INTIDs backing the device events are allocated one-by-one
and only upon Linux IRQ allocation; this to avoid preallocating
a large number of LPIs to cover the HW device MSI vector
size whereas few MSI entries are actually enabled by a device.

ITS cacheability/shareability attributes are programmed
according to the provided firmware ITS description.

The GICv5 ITS reuses the GICv3 MSI parent infrastructure,
there is no need to duplicate it, make it common.

Co-developed-by: Sascha Bischoff <sascha.bischoff@arm.com>
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Co-developed-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
---
 MAINTAINERS                                        |    1 +
 drivers/irqchip/Kconfig                            |   11 +
 drivers/irqchip/Makefile                           |    4 +-
 drivers/irqchip/irq-gic-common.h                   |    2 -
 ...3-its-msi-parent.c => irq-gic-its-msi-parent.c} |    3 +-
 drivers/irqchip/irq-gic-its-msi-parent.h           |   13 +
 drivers/irqchip/irq-gic-v3-its.c                   |    3 +-
 drivers/irqchip/irq-gic-v5-irs.c                   |   32 +
 drivers/irqchip/irq-gic-v5-its.c                   | 1294 ++++++++++++++++++++
 drivers/irqchip/irq-gic-v5.c                       |    6 +-
 drivers/irqchip/irq-gic-v5.h                       |  160 +++
 11 files changed, 1521 insertions(+), 8 deletions(-)

Comments

Thomas Gleixner April 9, 2025, 11:13 a.m. UTC | #1
On Tue, Apr 08 2025 at 12:50, Lorenzo Pieralisi wrote:
>  
> +void gicv5_irs_syncr(void)
> +{
> +	u32 syncr;
> +	u32 statusr;
> +	int ret;
> +	struct gicv5_irs_chip_data *irs_data;
> +
> +	irs_data = list_first_entry_or_null(&irs_nodes,
> +					    struct gicv5_irs_chip_data, entry);
> +	if (WARN_ON(!irs_data))
> +		return;
> +
> +	syncr = FIELD_PREP(GICV5_IRS_SYNCR_SYNC, 1);
> +	irs_writel(irs_data, syncr, GICV5_IRS_SYNCR);
> +
> +	ret = readl_relaxed_poll_timeout_atomic(
> +			irs_data->irs_base + GICV5_IRS_SYNC_STATUSR, statusr,
> +			FIELD_GET(GICV5_IRS_SYNC_STATUSR_IDLE, statusr), 1,
> +			USEC_PER_SEC);
> +
> +	if (ret == -ETIMEDOUT)
> +		pr_err_ratelimited("SYNCR timeout...\n");

This timeout poll thing looks very familiar by now. Third variant :)

> +static int gicv5_its_wait_for_invalidation(struct gicv5_its_chip_data *its)
> +{
> +	int ret;
> +	u32 statusr;
> +
> +	ret = readl_relaxed_poll_timeout_atomic(
> +			its->its_base + GICV5_ITS_STATUSR, statusr,
> +			FIELD_GET(GICV5_ITS_STATUSR_IDLE, statusr), 1,
> +			USEC_PER_SEC);
> +
> +	if (ret == -ETIMEDOUT)
> +		pr_err_ratelimited("STATUSR timeout...\n");
> +
> +	return ret;
> +}

And number four follows suit :)

> +
> +static void gicv5_its_syncr(struct gicv5_its_chip_data *its,
> +			    struct gicv5_its_dev *its_dev)
> +{
> +	int ret;
> +	u64 syncr;
> +	u32 statusr;
> +
> +	syncr = FIELD_PREP(GICV5_ITS_SYNCR_SYNC, 1) |
> +		FIELD_PREP(GICV5_ITS_SYNCR_DEVICEID, its_dev->device_id);
> +
> +	its_writeq(its, syncr, GICV5_ITS_SYNCR);
> +
> +	ret = readl_relaxed_poll_timeout_atomic(
> +			its->its_base + GICV5_ITS_SYNC_STATUSR, statusr,
> +			FIELD_GET(GICV5_ITS_SYNC_STATUSR_IDLE, statusr), 1,
> +			USEC_PER_SEC);
> +
> +	if (ret == -ETIMEDOUT)
> +		pr_err_ratelimited("SYNCR timeout...\n");
> +}

Along with #5 

Thanks,

        tglx
Lorenzo Pieralisi April 9, 2025, 1:37 p.m. UTC | #2
On Wed, Apr 09, 2025 at 01:13:46PM +0200, Thomas Gleixner wrote:
> On Tue, Apr 08 2025 at 12:50, Lorenzo Pieralisi wrote:
> >  
> > +void gicv5_irs_syncr(void)
> > +{
> > +	u32 syncr;
> > +	u32 statusr;
> > +	int ret;
> > +	struct gicv5_irs_chip_data *irs_data;
> > +
> > +	irs_data = list_first_entry_or_null(&irs_nodes,
> > +					    struct gicv5_irs_chip_data, entry);
> > +	if (WARN_ON(!irs_data))
> > +		return;
> > +
> > +	syncr = FIELD_PREP(GICV5_IRS_SYNCR_SYNC, 1);
> > +	irs_writel(irs_data, syncr, GICV5_IRS_SYNCR);
> > +
> > +	ret = readl_relaxed_poll_timeout_atomic(
> > +			irs_data->irs_base + GICV5_IRS_SYNC_STATUSR, statusr,
> > +			FIELD_GET(GICV5_IRS_SYNC_STATUSR_IDLE, statusr), 1,
> > +			USEC_PER_SEC);
> > +
> > +	if (ret == -ETIMEDOUT)
> > +		pr_err_ratelimited("SYNCR timeout...\n");
> 
> This timeout poll thing looks very familiar by now. Third variant :)
> 
> > +static int gicv5_its_wait_for_invalidation(struct gicv5_its_chip_data *its)
> > +{
> > +	int ret;
> > +	u32 statusr;
> > +
> > +	ret = readl_relaxed_poll_timeout_atomic(
> > +			its->its_base + GICV5_ITS_STATUSR, statusr,
> > +			FIELD_GET(GICV5_ITS_STATUSR_IDLE, statusr), 1,
> > +			USEC_PER_SEC);
> > +
> > +	if (ret == -ETIMEDOUT)
> > +		pr_err_ratelimited("STATUSR timeout...\n");
> > +
> > +	return ret;
> > +}
> 
> And number four follows suit :)
> 
> > +
> > +static void gicv5_its_syncr(struct gicv5_its_chip_data *its,
> > +			    struct gicv5_its_dev *its_dev)
> > +{
> > +	int ret;
> > +	u64 syncr;
> > +	u32 statusr;
> > +
> > +	syncr = FIELD_PREP(GICV5_ITS_SYNCR_SYNC, 1) |
> > +		FIELD_PREP(GICV5_ITS_SYNCR_DEVICEID, its_dev->device_id);
> > +
> > +	its_writeq(its, syncr, GICV5_ITS_SYNCR);
> > +
> > +	ret = readl_relaxed_poll_timeout_atomic(
> > +			its->its_base + GICV5_ITS_SYNC_STATUSR, statusr,
> > +			FIELD_GET(GICV5_ITS_SYNC_STATUSR_IDLE, statusr), 1,
> > +			USEC_PER_SEC);
> > +
> > +	if (ret == -ETIMEDOUT)
> > +		pr_err_ratelimited("SYNCR timeout...\n");
> > +}
> 
> Along with #5 

No question about it, I will consolidate them as much as I can, I
noticed while implementing them then focused on getting the driver
functionality in place and forgot to create a single function,
apologies.

Thanks,
Lorenzo
Thomas Gleixner April 9, 2025, 6:57 p.m. UTC | #3
On Tue, Apr 08 2025 at 12:50, Lorenzo Pieralisi wrote:
> +	guard(mutex)(&its->dev_alloc_lock);
> +
> +	its_dev = gicv5_its_find_device(its, device_id);
> +	if (IS_ERR(its_dev))
> +		return PTR_ERR(its_dev);
> +
> +	ret = gicv5_its_alloc_eventid(its_dev, nr_irqs, &event_id_base);
> +	if (ret)
> +		return ret;
> +
> +	ret = iommu_dma_prepare_msi(info->desc,
> +				    its->its_trans_phys_base);
> +	if (ret)
> +		goto out_eventid;

As 0-day already complained, guard() and goto does not mix. the simple
solution is to do

foo()
        guard()
        return __foo();

Then you can put the gotos into __foo()
Lorenzo Pieralisi April 10, 2025, 8:08 a.m. UTC | #4
On Wed, Apr 09, 2025 at 08:57:02PM +0200, Thomas Gleixner wrote:
> On Tue, Apr 08 2025 at 12:50, Lorenzo Pieralisi wrote:
> > +	guard(mutex)(&its->dev_alloc_lock);
> > +
> > +	its_dev = gicv5_its_find_device(its, device_id);
> > +	if (IS_ERR(its_dev))
> > +		return PTR_ERR(its_dev);
> > +
> > +	ret = gicv5_its_alloc_eventid(its_dev, nr_irqs, &event_id_base);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = iommu_dma_prepare_msi(info->desc,
> > +				    its->its_trans_phys_base);
> > +	if (ret)
> > +		goto out_eventid;
> 
> As 0-day already complained, guard() and goto does not mix. the simple
> solution is to do
> 
> foo()
>         guard()
>         return __foo();
> 
> Then you can put the gotos into __foo()

Yes even though its usage in this function IIUC is technically fine,
there are other kernel functions where the guard(mutex) is at the
function entry with gotos that follow.

Regardless, bad idea to mix them, as documented, thanks.

Side note: the bug the bot caught is because I moved the guard(mutex)
lower in the function and incidentally got past gotos (and gcc did not
catch it, it has to go up to W=2 to barf).

Anyway - as I mentioned in the cover letter, the current IWB driver
design, (patch 23 - where the guard(mutex) bug is and more readl_poll_*
boilerplate :), sorry), is a bit of a question (should I move it to
DOMAIN_BUS_WIRED_TO_MSI with the fixed eventid caveat to solve somehow),
or is it OK "as-is", treating it basically as an ITS hardcoded plugin ?

Thank you very much for having a look.

Lorenzo
Thomas Gleixner April 10, 2025, 9:20 a.m. UTC | #5
On Thu, Apr 10 2025 at 10:08, Lorenzo Pieralisi wrote:
> On Wed, Apr 09, 2025 at 08:57:02PM +0200, Thomas Gleixner wrote:
> Anyway - as I mentioned in the cover letter, the current IWB driver
> design, (patch 23 - where the guard(mutex) bug is and more readl_poll_*
> boilerplate :), sorry), is a bit of a question (should I move it to
> DOMAIN_BUS_WIRED_TO_MSI with the fixed eventid caveat to solve somehow),
> or is it OK "as-is", treating it basically as an ITS hardcoded plugin ?

I'm not sure whether DOMAIN_BUS_WIRED_TO_MSI buys much, but OTOH from a
layering perspective it's more in line with the existing wire to MSI
implementations. Marc might have an opinion there :)

Thanks,

        tglx
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index cdeceb6782355a4a18609135bf7f03249d8b0bb5..d231077c024deba42153663ac66b6c05f7673f03 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1908,6 +1908,7 @@  L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 F:	Documentation/devicetree/bindings/interrupt-controller/arm,gic-v5.yaml
 F:	arch/arm64/include/asm/arch_gicv5.h
+F:	drivers/irqchip/irq-gic-its-msi-parent.[ch]
 F:	drivers/irqchip/irq-gic-v5*.[ch]
 
 ARM HDLCD DRM DRIVER
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 160a4761d5d85f6dbf36f3142fd619c114733e36..6c348d421b05af0e4f4909877e02ac8ef19178ff 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -41,10 +41,14 @@  config ARM_GIC_V3
 	select HAVE_ARM_SMCCC_DISCOVERY
 	select IRQ_MSI_IOMMU
 
+config ARM_GIC_ITS_PARENT
+	bool
+
 config ARM_GIC_V3_ITS
 	bool
 	select GENERIC_MSI_IRQ
 	select IRQ_MSI_LIB
+	select ARM_GIC_ITS_PARENT
 	default ARM_GIC_V3
 	select IRQ_MSI_IOMMU
 
@@ -59,6 +63,13 @@  config ARM_GIC_V5
 	select IRQ_DOMAIN_HIERARCHY
 	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
+config ARM_GIC_V5_ITS
+	bool
+	select GENERIC_MSI_IRQ
+	select IRQ_MSI_LIB
+	select ARM_GIC_ITS_PARENT
+	default ARM_GIC_V5
+
 config ARM_NVIC
 	bool
 	select IRQ_DOMAIN_HIERARCHY
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 3d9c47fa3fdf40b7452c059d84fe8ac24c91bc0f..4280395e3bdff7858102f0b4eaaea1121cace52f 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -32,10 +32,12 @@  obj-$(CONFIG_ARCH_REALVIEW)		+= irq-gic-realview.o
 obj-$(CONFIG_IRQ_MSI_LIB)		+= irq-msi-lib.o
 obj-$(CONFIG_ARM_GIC_V2M)		+= irq-gic-v2m.o
 obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-v3-mbi.o irq-gic-common.o
-obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v4.o irq-gic-v3-its-msi-parent.o
+obj-$(CONFIG_ARM_GIC_ITS_PARENT)	+= irq-gic-its-msi-parent.o
+obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v4.o
 obj-$(CONFIG_ARM_GIC_V3_ITS_FSL_MC)	+= irq-gic-v3-its-fsl-mc-msi.o
 obj-$(CONFIG_PARTITION_PERCPU)		+= irq-partition-percpu.o
 obj-$(CONFIG_ARM_GIC_V5)		+= irq-gic-v5.o irq-gic-v5-irs.o
+obj-$(CONFIG_ARM_GIC_V5_ITS)		+= irq-gic-v5-its.o
 obj-$(CONFIG_HISILICON_IRQ_MBIGEN)	+= irq-mbigen.o
 obj-$(CONFIG_ARM_NVIC)			+= irq-nvic.o
 obj-$(CONFIG_ARM_VIC)			+= irq-vic.o
diff --git a/drivers/irqchip/irq-gic-common.h b/drivers/irqchip/irq-gic-common.h
index 020ecdf16901c9720e5746aec4d0b5b39d3625ed..710cab61d9195a0bd64d57e03c60852c4cd6ff8e 100644
--- a/drivers/irqchip/irq-gic-common.h
+++ b/drivers/irqchip/irq-gic-common.h
@@ -29,8 +29,6 @@  void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
 void gic_enable_of_quirks(const struct device_node *np,
 			  const struct gic_quirk *quirks, void *data);
 
-extern const struct msi_parent_ops gic_v3_its_msi_parent_ops;
-
 #define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING    (1 << 0)
 #define RDIST_FLAGS_RD_TABLES_PREALLOCATED     (1 << 1)
 #define RDIST_FLAGS_FORCE_NON_SHAREABLE        (1 << 2)
diff --git a/drivers/irqchip/irq-gic-v3-its-msi-parent.c b/drivers/irqchip/irq-gic-its-msi-parent.c
similarity index 98%
rename from drivers/irqchip/irq-gic-v3-its-msi-parent.c
rename to drivers/irqchip/irq-gic-its-msi-parent.c
index bdb04c8081480de468fb217b68c6933a8e1e2bd7..71edcdb2defdfd5b892d86354039d2e46b832ea5 100644
--- a/drivers/irqchip/irq-gic-v3-its-msi-parent.c
+++ b/drivers/irqchip/irq-gic-its-msi-parent.c
@@ -7,7 +7,6 @@ 
 #include <linux/acpi_iort.h>
 #include <linux/pci.h>
 
-#include "irq-gic-common.h"
 #include "irq-msi-lib.h"
 
 #define ITS_MSI_FLAGS_REQUIRED  (MSI_FLAG_USE_DEF_DOM_OPS |	\
@@ -200,7 +199,7 @@  static bool its_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
 	return true;
 }
 
-const struct msi_parent_ops gic_v3_its_msi_parent_ops = {
+const struct msi_parent_ops gic_its_msi_parent_ops = {
 	.supported_flags	= ITS_MSI_FLAGS_SUPPORTED,
 	.required_flags		= ITS_MSI_FLAGS_REQUIRED,
 	.chip_flags		= MSI_CHIP_FLAG_SET_EOI | MSI_CHIP_FLAG_SET_ACK,
diff --git a/drivers/irqchip/irq-gic-its-msi-parent.h b/drivers/irqchip/irq-gic-its-msi-parent.h
new file mode 100644
index 0000000000000000000000000000000000000000..e7bb7f3862eef379e5b85fe7bd5eb72f3586d3b7
--- /dev/null
+++ b/drivers/irqchip/irq-gic-its-msi-parent.h
@@ -0,0 +1,13 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2024 ARM Limited, All Rights Reserved.
+ */
+
+#ifndef _IRQ_GIC_ITS_MSI_PARENT_H
+#define _IRQ_GIC_ITS_MSI_PARENT_H
+
+#include <linux/msi.h>
+
+extern const struct msi_parent_ops gic_its_msi_parent_ops;
+
+#endif /* _IRQ_GIC_ITS_MSI_PARENT_H */
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 0115ad6c82593de511c285d99437996919bfa308..6c51bf4e34a38103d612c74476d640cd4126e8b6 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -41,6 +41,7 @@ 
 #include <asm/exception.h>
 
 #include "irq-gic-common.h"
+#include "irq-gic-its-msi-parent.h"
 #include "irq-msi-lib.h"
 
 #define ITS_FLAGS_CMDQ_NEEDS_FLUSHING		(1ULL << 0)
@@ -5139,7 +5140,7 @@  static int its_init_domain(struct its_node *its)
 
 	irq_domain_update_bus_token(inner_domain, DOMAIN_BUS_NEXUS);
 
-	inner_domain->msi_parent_ops = &gic_v3_its_msi_parent_ops;
+	inner_domain->msi_parent_ops = &gic_its_msi_parent_ops;
 	inner_domain->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT;
 
 	return 0;
diff --git a/drivers/irqchip/irq-gic-v5-irs.c b/drivers/irqchip/irq-gic-v5-irs.c
index 909ccf07879a1feb5abb65fa265706f2c276d927..3078baa57ec669db962796efe72f881342217a52 100644
--- a/drivers/irqchip/irq-gic-v5-irs.c
+++ b/drivers/irqchip/irq-gic-v5-irs.c
@@ -507,6 +507,30 @@  static int gicv5_irs_wait_for_idle(struct gicv5_irs_chip_data *irs_data)
 	return ret;
 }
 
+void gicv5_irs_syncr(void)
+{
+	u32 syncr;
+	u32 statusr;
+	int ret;
+	struct gicv5_irs_chip_data *irs_data;
+
+	irs_data = list_first_entry_or_null(&irs_nodes,
+					    struct gicv5_irs_chip_data, entry);
+	if (WARN_ON(!irs_data))
+		return;
+
+	syncr = FIELD_PREP(GICV5_IRS_SYNCR_SYNC, 1);
+	irs_writel(irs_data, syncr, GICV5_IRS_SYNCR);
+
+	ret = readl_relaxed_poll_timeout_atomic(
+			irs_data->irs_base + GICV5_IRS_SYNC_STATUSR, statusr,
+			FIELD_GET(GICV5_IRS_SYNC_STATUSR_IDLE, statusr), 1,
+			USEC_PER_SEC);
+
+	if (ret == -ETIMEDOUT)
+		pr_err_ratelimited("SYNCR timeout...\n");
+}
+
 int gicv5_irs_register_cpu(int cpuid)
 {
 	struct gicv5_irs_chip_data *irs_data;
@@ -803,6 +827,14 @@  int __init gicv5_irs_enable(void)
 	return 0;
 }
 
+void __init gicv5_irs_its_probe(void)
+{
+	struct gicv5_irs_chip_data *irs_data;
+
+	list_for_each_entry(irs_data, &irs_nodes, entry)
+		gicv5_its_of_probe(to_of_node(irs_data->fwnode));
+}
+
 int __init gicv5_irs_of_probe(struct device_node *parent)
 {
 	int ret;
diff --git a/drivers/irqchip/irq-gic-v5-its.c b/drivers/irqchip/irq-gic-v5-its.c
new file mode 100644
index 0000000000000000000000000000000000000000..f4f381e6c3af896f354e7e03bc2452b8a65cf093
--- /dev/null
+++ b/drivers/irqchip/irq-gic-v5-its.c
@@ -0,0 +1,1294 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024-2025 ARM Limited, All Rights Reserved.
+ */
+
+#define pr_fmt(fmt)	"GICv5 ITS: " fmt
+
+#include <linux/bitmap.h>
+#include <linux/iommu.h>
+#include <linux/iopoll.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/msi.h>
+
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <linux/slab.h>
+
+#include <linux/irqchip.h>
+
+#include "irq-gic-v5.h"
+#include "irq-gic-its-msi-parent.h"
+#include "irq-msi-lib.h"
+
+#define ITS_FLAGS_NON_COHERENT		BIT(0)
+
+static LIST_HEAD(its_nodes);
+
+static u32 its_readl(struct gicv5_its_chip_data *its_node, const u64 reg_offset)
+{
+	return readl_relaxed(its_node->its_base + reg_offset);
+}
+
+static void its_writel(struct gicv5_its_chip_data *its_node, const u32 val,
+		       const u64 reg_offset)
+{
+	writel_relaxed(val, its_node->its_base + reg_offset);
+}
+
+static void its_writeq(struct gicv5_its_chip_data *its_node, const u64 val,
+		       const u64 reg_offset)
+{
+	writeq_relaxed(val, its_node->its_base + reg_offset);
+}
+
+static void its_write_table_entry(struct gicv5_its_chip_data *its,
+				  __le64 *entry, u64 val)
+{
+	WRITE_ONCE(*entry, val);
+	if (its->flags & ITS_FLAGS_NON_COHERENT)
+		dcache_clean_inval_poc((unsigned long)entry,
+				       (unsigned long)entry + sizeof(*entry));
+	else
+		dsb(ishst);
+}
+
+static int gicv5_its_wait_for_invalidation(struct gicv5_its_chip_data *its)
+{
+	int ret;
+	u32 statusr;
+
+	ret = readl_relaxed_poll_timeout_atomic(
+			its->its_base + GICV5_ITS_STATUSR, statusr,
+			FIELD_GET(GICV5_ITS_STATUSR_IDLE, statusr), 1,
+			USEC_PER_SEC);
+
+	if (ret == -ETIMEDOUT)
+		pr_err_ratelimited("STATUSR timeout...\n");
+
+	return ret;
+}
+
+static void gicv5_its_syncr(struct gicv5_its_chip_data *its,
+			    struct gicv5_its_dev *its_dev)
+{
+	int ret;
+	u64 syncr;
+	u32 statusr;
+
+	syncr = FIELD_PREP(GICV5_ITS_SYNCR_SYNC, 1) |
+		FIELD_PREP(GICV5_ITS_SYNCR_DEVICEID, its_dev->device_id);
+
+	its_writeq(its, syncr, GICV5_ITS_SYNCR);
+
+	ret = readl_relaxed_poll_timeout_atomic(
+			its->its_base + GICV5_ITS_SYNC_STATUSR, statusr,
+			FIELD_GET(GICV5_ITS_SYNC_STATUSR_IDLE, statusr), 1,
+			USEC_PER_SEC);
+
+	if (ret == -ETIMEDOUT)
+		pr_err_ratelimited("SYNCR timeout...\n");
+}
+
+static int gicv5_its_l2sz_to_l2_bits(unsigned int sz)
+{
+	switch (sz) {
+	case GICV5_ITS_DT_ITT_CFGR_L2SZ_4k:
+		return 9;
+	case GICV5_ITS_DT_ITT_CFGR_L2SZ_16k:
+		return 11;
+	case GICV5_ITS_DT_ITT_CFGR_L2SZ_64k:
+		return 13;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int gicv5_its_itt_cache_inv(struct gicv5_its_chip_data *its,
+				   u32 device_id, u16 event_id)
+{
+	u64 didr;
+	u32 eventr, eidr;
+
+	didr = FIELD_PREP(GICV5_ITS_DIDR_DEVICEID, device_id);
+	eidr = FIELD_PREP(GICV5_ITS_EIDR_EVENTID, event_id);
+	eventr = FIELD_PREP(GICV5_ITS_INV_EVENTR_I, 0x1);
+
+	its_writeq(its, didr, GICV5_ITS_DIDR);
+	its_writel(its, eidr, GICV5_ITS_EIDR);
+	its_writel(its, eventr, GICV5_ITS_INV_EVENTR);
+
+	return gicv5_its_wait_for_invalidation(its);
+}
+
+static void gicv5_its_free_itt_linear(struct gicv5_its_dev *its_dev)
+{
+	kfree(its_dev->itt_cfg.linear.itt);
+}
+
+static void gicv5_its_free_itt_two_level(struct gicv5_its_dev *its_dev)
+{
+	unsigned int i, num_ents = its_dev->itt_cfg.l2.num_l1_ents;
+
+	for (i = 0; i < num_ents; i++)
+		kfree(its_dev->itt_cfg.l2.l2ptrs[i]);
+
+	kfree(its_dev->itt_cfg.l2.l2ptrs);
+	kfree(its_dev->itt_cfg.l2.l1itt);
+}
+
+static void gicv5_its_free_itt(struct gicv5_its_dev *its_dev)
+{
+	if (!its_dev->itt_cfg.l2itt)
+		gicv5_its_free_itt_linear(its_dev);
+	else
+		gicv5_its_free_itt_two_level(its_dev);
+}
+
+static int gicv5_its_create_itt_linear(struct gicv5_its_chip_data *its,
+				       struct gicv5_its_dev *its_dev,
+				       unsigned int event_id_bits)
+{
+	__le64 *itt;
+	unsigned int num_ents = BIT(event_id_bits);
+
+	itt = kcalloc(num_ents, sizeof(*itt), GFP_KERNEL);
+	if (!itt)
+		return -ENOMEM;
+
+	its_dev->itt_cfg.linear.itt = itt;
+	its_dev->itt_cfg.linear.num_ents = num_ents;
+	its_dev->itt_cfg.l2itt = false;
+	its_dev->itt_cfg.event_id_bits = event_id_bits;
+
+	if (its->flags & ITS_FLAGS_NON_COHERENT)
+		dcache_clean_inval_poc((unsigned long)itt,
+				(unsigned long)itt + num_ents * sizeof(*itt));
+	else
+		dsb(ishst);
+
+	return 0;
+}
+
+/*
+ * Allocate a two-level ITT. All ITT entries are allocated in one go, unlike
+ * with the device table. Span may be used to limit the second level table
+ * size, where possible.
+ */
+static int gicv5_its_create_itt_two_level(struct gicv5_its_chip_data *its,
+					  struct gicv5_its_dev *its_dev,
+					  unsigned int event_id_bits,
+					  unsigned int itt_l2sz,
+					  unsigned int num_events)
+{
+	u64 val;
+	int ret, i;
+	__le64 *itt_l1, *itt_l2, **l2ptrs;
+	unsigned int l1_bits, l2_bits, span, events_per_l2_table,
+		complete_tables, final_span, num_ents;
+
+	ret = gicv5_its_l2sz_to_l2_bits(itt_l2sz);
+	if (ret < 0 || ret >= event_id_bits) {
+		pr_debug("Incorrect l2sz (0x%x) for %u EventID bits. Cannot allocate ITT\n",
+		       itt_l2sz, event_id_bits);
+		return -EINVAL;
+	}
+
+	l2_bits = ret;
+
+	l1_bits = event_id_bits - l2_bits;
+
+	num_ents = BIT(l1_bits);
+
+	itt_l1 = kcalloc(num_ents, sizeof(*itt_l1), GFP_KERNEL);
+	if (!itt_l1)
+		return -ENOMEM;
+
+	l2ptrs = kcalloc(num_ents, sizeof(*l2ptrs), GFP_KERNEL);
+	if (!l2ptrs) {
+		kfree(itt_l1);
+		return -ENOMEM;
+	}
+
+	its_dev->itt_cfg.l2.l2ptrs = l2ptrs;
+
+	its_dev->itt_cfg.l2.l2sz = itt_l2sz;
+	its_dev->itt_cfg.l2.l1itt = itt_l1;
+	its_dev->itt_cfg.l2.num_l1_ents = num_ents;
+	its_dev->itt_cfg.l2itt = true;
+	its_dev->itt_cfg.event_id_bits = event_id_bits;
+
+	/*
+	 * Need to determine how many entries there are per L2 - this is based
+	 * on the number of bits in the table.
+	 */
+	events_per_l2_table = BIT(l2_bits);
+	complete_tables = num_events / events_per_l2_table;
+	final_span = order_base_2(num_events % events_per_l2_table);
+
+	for (i = 0; i < num_ents; i++) {
+		size_t l2sz;
+
+		span = i == complete_tables ? final_span : l2_bits;
+
+		itt_l2 = kcalloc(BIT(span), sizeof(*itt_l2), GFP_KERNEL);
+		if (!itt_l2) {
+			ret = -ENOMEM;
+			goto out_free;
+		}
+
+		its_dev->itt_cfg.l2.l2ptrs[i] = itt_l2;
+
+		l2sz = BIT(span) * sizeof(*itt_l2);
+
+		if (its->flags & ITS_FLAGS_NON_COHERENT)
+			dcache_clean_inval_poc((unsigned long)itt_l2,
+				(unsigned long)itt_l2 + l2sz);
+
+		val = (virt_to_phys(itt_l2) & GICV5_ITTL1E_L2_ADDR_MASK) |
+		       FIELD_PREP(GICV5_ITTL1E_SPAN, span)		 |
+		       FIELD_PREP(GICV5_ITTL1E_VALID, 0x1);
+
+		WRITE_ONCE(itt_l1[i], cpu_to_le64(val));
+	}
+
+	if (its->flags & ITS_FLAGS_NON_COHERENT)
+		dcache_clean_inval_poc((unsigned long)itt_l1,
+			(unsigned long)itt_l1 +	 num_ents * sizeof(*itt_l1));
+	else
+		dsb(ishst);
+
+	return 0;
+out_free:
+	for (i = i - 1; i >= 0; i--)
+		kfree(its_dev->itt_cfg.l2.l2ptrs[i]);
+
+	kfree(its_dev->itt_cfg.l2.l2ptrs);
+	kfree(itt_l1);
+	return ret;
+}
+
+/*
+ * Function to check whether the device table or ITT table support
+ * a two-level table and if so depending on the number of id_bits
+ * requested, determine whether a two-level table is required.
+ *
+ * Return the 2-level size value if a two level table is deemed
+ * necessary.
+ */
+static bool gicv5_its_l2sz_two_level(bool devtab, u32 its_idr1, u8 id_bits,
+				     u8 *sz)
+{
+	int l2_bits, l2_sz = -EINVAL;
+
+	if (devtab && !FIELD_GET(GICV5_ITS_IDR1_DT_LEVELS, its_idr1))
+		return false;
+
+	if (!devtab && !FIELD_GET(GICV5_ITS_IDR1_ITT_LEVELS, its_idr1))
+		return false;
+
+	/*
+	 * Pick an L2 size that matches the pagesize; if a match
+	 * is not found, go for the smallest supported l2 size granule.
+	 *
+	 * This ensures that we will always be able to allocate
+	 * contiguous memory at L2.
+	 */
+	switch (PAGE_SIZE) {
+	case SZ_64K:
+		if (GICV5_ITS_IDR1_L2SZ_SUPPORT_64KB(its_idr1)) {
+			l2_sz = GICV5_ITS_DT_ITT_CFGR_L2SZ_64k;
+			break;
+		}
+		fallthrough;
+	case SZ_16K:
+		if (GICV5_ITS_IDR1_L2SZ_SUPPORT_16KB(its_idr1)) {
+			l2_sz = GICV5_ITS_DT_ITT_CFGR_L2SZ_16k;
+			break;
+		}
+		fallthrough;
+	case SZ_4K:
+		if (GICV5_ITS_IDR1_L2SZ_SUPPORT_4KB(its_idr1)) {
+			l2_sz = GICV5_ITS_DT_ITT_CFGR_L2SZ_4k;
+			break;
+		}
+		if (GICV5_ITS_IDR1_L2SZ_SUPPORT_16KB(its_idr1)) {
+			l2_sz = GICV5_ITS_DT_ITT_CFGR_L2SZ_16k;
+			break;
+		}
+		if (GICV5_ITS_IDR1_L2SZ_SUPPORT_64KB(its_idr1)) {
+			l2_sz = GICV5_ITS_DT_ITT_CFGR_L2SZ_64k;
+			break;
+		}
+		break;
+	}
+
+	l2_bits = gicv5_its_l2sz_to_l2_bits(l2_sz);
+
+	if (l2_bits < 0 || l2_bits > id_bits)
+		return false;
+
+	*sz = l2_sz;
+
+	return true;
+}
+
+static int gicv5_its_device_get_itte_ref(struct gicv5_its_dev *its_dev,
+					 __le64 **itte, u16 event_id)
+{
+	if (!its_dev->itt_cfg.l2itt) {
+		__le64 *itt = its_dev->itt_cfg.linear.itt;
+		*itte = &itt[event_id];
+	} else {
+		unsigned int l1_idx, l2_idx, l2_size, l2_bits;
+		__le64 *l2_itt, *l1_itt = its_dev->itt_cfg.l2.l1itt;
+		int ret;
+
+		ret = gicv5_its_l2sz_to_l2_bits(its_dev->itt_cfg.l2.l2sz);
+		if (ret < 0)
+			return ret;
+		l2_bits = ret;
+
+		l1_idx = event_id >> l2_bits;
+
+		if (!FIELD_GET(GICV5_ITTL1E_VALID,
+			       le64_to_cpu(l1_itt[l1_idx]))) {
+			pr_debug("L1 ITT entry is not valid.\n");
+			return -EINVAL;
+		}
+
+		l2_idx = event_id & GENMASK(l2_bits - 1, 0);
+
+		l2_size = BIT(FIELD_GET(GICV5_ITTL1E_SPAN,
+					le64_to_cpu(l1_itt[l1_idx])));
+
+		// Sanity check our indexing
+		if (l2_idx >= l2_size) {
+			pr_debug("L2 ITT index (%u) exceeds L2 table size (%u)!\n",
+			       l2_idx, l2_size);
+			return -EINVAL;
+		}
+		l2_itt = its_dev->itt_cfg.l2.l2ptrs[l1_idx];
+		*itte = &l2_itt[l2_idx];
+	}
+
+	return 0;
+}
+
+static int gicv5_its_device_cache_inv(struct gicv5_its_chip_data *its,
+				      struct gicv5_its_dev *its_dev)
+{
+	u32 devicer;
+	u64 didr;
+
+	didr = FIELD_PREP(GICV5_ITS_DIDR_DEVICEID, its_dev->device_id);
+	devicer = FIELD_PREP(GICV5_ITS_INV_DEVICER_I, 0x1)	|
+		  FIELD_PREP(GICV5_ITS_INV_DEVICER_EVENTID_BITS,
+			     its_dev->itt_cfg.event_id_bits)	|
+		  FIELD_PREP(GICV5_ITS_INV_DEVICER_L1, 0x0);
+	its_writeq(its, didr, GICV5_ITS_DIDR);
+	its_writel(its, devicer, GICV5_ITS_INV_DEVICER);
+
+	return gicv5_its_wait_for_invalidation(its);
+}
+
+/*
+ * Allocate a level 2 device table entry, update L1 parent to reference it.
+ * Only used for 2-level device tables, and it is called on demand.
+ */
+static int gicv5_its_alloc_l2_devtab(struct gicv5_its_chip_data *its,
+				     unsigned int l1_index)
+{
+	int ret;
+	u64 l1dte;
+	u8 span, l2sz, l2_bits;
+	__le64 *l2devtab, *l1devtab = its->devtab_cfgr.l2.l1devtab;
+
+	if (FIELD_GET(GICV5_DTL1E_VALID, le64_to_cpu(l1devtab[l1_index])))
+		return 0;
+
+	span = FIELD_GET(GICV5_DTL1E_SPAN, le64_to_cpu(l1devtab[l1_index]));
+	l2sz = FIELD_GET(GICV5_ITS_DT_CFGR_L2SZ, its->devtab_cfgr.cfgr);
+
+	ret = gicv5_its_l2sz_to_l2_bits(l2sz);
+	if (ret < 0)
+		return ret;
+
+	l2_bits = ret;
+
+	/*
+	 * Span allows us to create a smaller L2 device table.
+	 * If it is too large, use the number of allowed L2 bits.
+	 */
+	if (span > l2_bits)
+		span = l2_bits;
+
+	l2devtab = kcalloc(BIT(span), sizeof(*l2devtab), GFP_KERNEL);
+	if (!l2devtab)
+		return -ENOMEM;
+
+	its->devtab_cfgr.l2.l2ptrs[l1_index] = l2devtab;
+
+	l1dte = FIELD_PREP(GICV5_DTL1E_SPAN, span)			|
+		(virt_to_phys(l2devtab) & GICV5_DTL1E_L2_ADDR_MASK)	|
+		FIELD_PREP(GICV5_DTL1E_VALID, 0x1);
+	its_write_table_entry(its, &l1devtab[l1_index], cpu_to_le64(l1dte));
+
+	return 0;
+}
+
+static int gicv5_its_devtab_get_dte_ref(struct gicv5_its_chip_data *its,
+					__le64 **dte, u32 device_id,
+					bool alloc)
+{
+	int ret;
+	__le64 *l1devtab, *l2devtab;
+	unsigned int l2sz, l2_bits, l1_idx, l2_idx;
+	u8 str = FIELD_GET(GICV5_ITS_DT_CFGR_STRUCTURE, its->devtab_cfgr.cfgr);
+
+	if (str == GICV5_ITS_DT_ITT_CFGR_STRUCTURE_LINEAR) {
+		l2devtab = its->devtab_cfgr.linear.devtab;
+		*dte = &l2devtab[device_id];
+	} else {
+		l2sz = FIELD_GET(GICV5_ITS_DT_CFGR_L2SZ, its->devtab_cfgr.cfgr);
+		l1devtab = its->devtab_cfgr.l2.l1devtab;
+
+		ret = gicv5_its_l2sz_to_l2_bits(l2sz);
+		if (ret < 0)
+			return -EINVAL;
+
+		l2_bits = ret;
+		l1_idx = device_id >> l2_bits;
+		l2_idx = device_id & GENMASK(l2_bits - 1, 0);
+
+		if (alloc) {
+			/*
+			 * Allocate a new L2 device table here before
+			 * continuing. We make the assumption that the span in
+			 * the L1 table has been set correctly, and blindly use
+			 * that value.
+			 */
+			ret = gicv5_its_alloc_l2_devtab(its, l1_idx);
+			if (ret)
+				return ret;
+		} else {
+			if (!FIELD_GET(GICV5_DTL1E_VALID,
+				       le64_to_cpu(l1devtab[l1_idx])))
+				return -EINVAL;
+		}
+
+
+		l2devtab = its->devtab_cfgr.l2.l2ptrs[l1_idx];
+		*dte = &l2devtab[l2_idx];
+	}
+
+	return 0;
+}
+
+/*
+ * Register a new device in the device table. Allocate an ITT and
+ * program the L2DTE entry according to the ITT structure that
+ * was chosen.
+ */
+static int gicv5_its_device_register(struct gicv5_its_chip_data *its,
+				     struct gicv5_its_dev *its_dev)
+{
+	u8 event_id_bits, device_id_bits, itt_struct, itt_l2sz;
+	phys_addr_t itt_phys_base;
+	u32 idr1, idr2;
+	bool two_level_itt;
+	__le64 *dte;
+	int ret;
+	u64 val;
+
+	device_id_bits = FIELD_GET(GICV5_ITS_DT_CFGR_DEVICEID_BITS,
+				   its->devtab_cfgr.cfgr);
+
+	if (its_dev->device_id >= BIT(device_id_bits)) {
+		pr_err("Supplied DeviceID (%u) outside of Device Table range (%u)!",
+		       its_dev->device_id, (u32)GENMASK(device_id_bits - 1, 0));
+		return -EINVAL;
+	}
+
+	ret = gicv5_its_devtab_get_dte_ref(its, &dte, its_dev->device_id, true);
+	if (ret)
+		return ret;
+
+	if (FIELD_GET(GICV5_DTL2E_VALID, le64_to_cpu(*dte)))
+		return -EBUSY;
+
+	/*
+	 * Determine how many bits we need, validate those against the max.
+	 * Based on these, determine if we should go for a 1- or 2-level ITT.
+	 */
+	event_id_bits = order_base_2(its_dev->num_events);
+
+	idr2 = its_readl(its, GICV5_ITS_IDR2);
+
+	if (event_id_bits > FIELD_GET(GICV5_ITS_IDR2_EVENTID_BITS, idr2)) {
+		pr_err("Required EventID bits (%u) larger than supported bits (%u)!",
+		       event_id_bits,
+		       (u8)FIELD_GET(GICV5_ITS_IDR2_EVENTID_BITS, idr2));
+		return -EINVAL;
+	}
+
+	idr1 = its_readl(its, GICV5_ITS_IDR1);
+
+	/*
+	 * L2 ITT size is programmed into the L2DTE regardless of
+	 * whether a two-level or linear ITT is built, init it.
+	 */
+	itt_l2sz = 0;
+
+	two_level_itt = gicv5_its_l2sz_two_level(false, idr1, event_id_bits,
+						  &itt_l2sz);
+	if (two_level_itt)
+		ret = gicv5_its_create_itt_two_level(its, its_dev, event_id_bits,
+						     itt_l2sz,
+						     its_dev->num_events);
+	else
+		ret = gicv5_its_create_itt_linear(its, its_dev, event_id_bits);
+	if (ret)
+		return ret;
+
+	itt_phys_base = two_level_itt ?
+		virt_to_phys(its_dev->itt_cfg.l2.l1itt) :
+		virt_to_phys(its_dev->itt_cfg.linear.itt);
+
+	itt_struct = two_level_itt ? GICV5_ITS_DT_ITT_CFGR_STRUCTURE_TWO_LEVEL :
+				     GICV5_ITS_DT_ITT_CFGR_STRUCTURE_LINEAR;
+
+	val = FIELD_PREP(GICV5_DTL2E_EVENT_ID_BITS, event_id_bits)	|
+	      FIELD_PREP(GICV5_DTL2E_ITT_STRUCTURE, itt_struct)		|
+	      (itt_phys_base & GICV5_DTL2E_ITT_ADDR_MASK)		|
+	      FIELD_PREP(GICV5_DTL2E_ITT_L2SZ, itt_l2sz)		|
+	      FIELD_PREP(GICV5_DTL2E_VALID, 0x1);
+
+	its_write_table_entry(its, dte, cpu_to_le64(val));
+
+	ret = gicv5_its_device_cache_inv(its, its_dev);
+	if (ret) {
+		gicv5_its_free_itt(its_dev);
+		its_write_table_entry(its, dte, 0);
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Unregister a device in the device table. Lookup the device by ID, free the
+ * corresponding ITT, mark the device as invalid in the device table.
+ */
+static int gicv5_its_device_unregister(struct gicv5_its_chip_data *its,
+				       struct gicv5_its_dev *its_dev)
+{
+	int ret;
+	__le64 *dte;
+
+	ret = gicv5_its_devtab_get_dte_ref(its, &dte, its_dev->device_id, false);
+	if (ret) {
+		pr_debug("Failed to find DTE for DeviceID 0x%x\n", its_dev->device_id);
+		return -EINVAL;
+	}
+
+	if (!FIELD_GET(GICV5_DTL2E_VALID, le64_to_cpu(*dte))) {
+		pr_debug("Device table entry for DeviceID 0x%x is not valid. Nothing to clean up!",
+		       its_dev->device_id);
+		return -EINVAL;
+	}
+
+	gicv5_its_free_itt(its_dev);
+
+	/* Zero everything - make it clear that this is an invalid entry */
+	its_write_table_entry(its, dte, 0);
+
+	return gicv5_its_device_cache_inv(its, its_dev);
+}
+
+/*
+ * Allocate a 1-level device table. All entries are allocated, but marked
+ * invalid.
+ */
+static int gicv5_its_alloc_devtab_linear(struct gicv5_its_chip_data *its,
+					u8 device_id_bits)
+{
+	u32 cfgr;
+	u64 baser;
+	size_t sz;
+	__le64 *devtab;
+
+	sz = BIT_ULL(device_id_bits) * sizeof(*devtab);
+	if (sz > KMALLOC_MAX_SIZE) {
+		u8 device_id_cap = ilog2(KMALLOC_MAX_SIZE/sizeof(*devtab));
+
+		pr_warn("Limiting device ID bits from %u to %u\n",
+			device_id_bits, device_id_cap);
+		device_id_bits = device_id_cap;
+	}
+
+	devtab = kcalloc(BIT(device_id_bits), sizeof(*devtab), GFP_KERNEL);
+	if (!devtab)
+		return -ENOMEM;
+
+	if (its->flags & ITS_FLAGS_NON_COHERENT)
+		dcache_clean_inval_poc((unsigned long)devtab,
+				       (unsigned long)devtab + sz);
+	else
+		dsb(ishst);
+
+	cfgr = FIELD_PREP(GICV5_ITS_DT_CFGR_STRUCTURE,
+			  GICV5_ITS_DT_ITT_CFGR_STRUCTURE_LINEAR)	|
+	       FIELD_PREP(GICV5_ITS_DT_CFGR_L2SZ, 0)			|
+	       FIELD_PREP(GICV5_ITS_DT_CFGR_DEVICEID_BITS, device_id_bits);
+	its_writel(its, cfgr, GICV5_ITS_DT_CFGR);
+
+	baser = virt_to_phys(devtab) & GICV5_ITS_DT_BASER_ADDR_MASK;
+	its_writeq(its, baser, GICV5_ITS_DT_BASER);
+
+	its->devtab_cfgr.cfgr = cfgr;
+	its->devtab_cfgr.linear.devtab = devtab;
+
+	return 0;
+}
+
+/*
+ * Allocate a 2-level device table. L2 entries are not allocated,
+ * they are allocated on-demand.
+ */
+static int gicv5_its_alloc_devtab_two_level(struct gicv5_its_chip_data *its,
+					    u8 device_id_bits,
+					    u8 devtab_l2sz)
+{
+	int ret;
+	u64 baser;
+	u32 cfgr;
+	size_t l1_sz;
+	__le64 *l1devtab, **l2ptrs;
+	unsigned int l1_bits, l2_bits, i;
+
+	ret = gicv5_its_l2sz_to_l2_bits(devtab_l2sz);
+	if (ret < 0)
+		return ret;
+
+	l2_bits = ret;
+
+	l1_bits = device_id_bits - l2_bits;
+	l1_sz = BIT(l1_bits) * sizeof(*l1devtab);
+	if (l1_sz > KMALLOC_MAX_SIZE) {
+		l1_bits = ilog2(KMALLOC_MAX_SIZE/sizeof(*l1devtab));
+
+		pr_warn("Limiting device ID bits from %u to %u\n",
+			device_id_bits, l1_bits + l2_bits);
+		device_id_bits = l1_bits + l2_bits;
+		l1_sz = KMALLOC_MAX_SIZE;
+	}
+
+	l1devtab = kcalloc(BIT(l1_bits), sizeof(*l1devtab), GFP_KERNEL);
+	if (!l1devtab)
+		return -ENOMEM;
+
+	l2ptrs = kcalloc(BIT(l1_bits), sizeof(*l2ptrs), GFP_KERNEL);
+	if (!l2ptrs) {
+		kfree(l1devtab);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < BIT(l1_bits); i++)
+		l1devtab[i] = cpu_to_le64(FIELD_PREP(GICV5_DTL1E_SPAN, l2_bits));
+
+	if (its->flags & ITS_FLAGS_NON_COHERENT)
+		dcache_clean_inval_poc((unsigned long)l1devtab,
+				       (unsigned long)l1devtab + l1_sz);
+	else
+		dsb(ishst);
+
+	cfgr = FIELD_PREP(GICV5_ITS_DT_CFGR_STRUCTURE,
+			  GICV5_ITS_DT_ITT_CFGR_STRUCTURE_TWO_LEVEL)	|
+	       FIELD_PREP(GICV5_ITS_DT_CFGR_L2SZ, devtab_l2sz)		|
+	       FIELD_PREP(GICV5_ITS_DT_CFGR_DEVICEID_BITS, device_id_bits);
+	its_writel(its, cfgr, GICV5_ITS_DT_CFGR);
+
+	baser = virt_to_phys(l1devtab) & GICV5_ITS_DT_BASER_ADDR_MASK;
+	its_writeq(its, baser, GICV5_ITS_DT_BASER);
+
+	its->devtab_cfgr.cfgr = cfgr;
+	its->devtab_cfgr.l2.l1devtab = l1devtab;
+	its->devtab_cfgr.l2.l2ptrs = l2ptrs;
+
+	return 0;
+}
+
+/*
+ * Initialise the device table as either 1- or 2-level depending on what is
+ * supported by the hardware.
+ */
+static int gicv5_its_init_devtab(struct gicv5_its_chip_data *its)
+{
+	u32 idr1;
+	bool two_level_devtab;
+	u8 device_id_bits, devtab_l2sz;
+
+	idr1 = its_readl(its, GICV5_ITS_IDR1);
+
+	device_id_bits = FIELD_GET(GICV5_ITS_IDR1_DEVICEID_BITS, idr1);
+	two_level_devtab = gicv5_its_l2sz_two_level(true, idr1, device_id_bits,
+						     &devtab_l2sz);
+	if (two_level_devtab)
+		return gicv5_its_alloc_devtab_two_level(its, device_id_bits,
+						       devtab_l2sz);
+	else
+		return gicv5_its_alloc_devtab_linear(its, device_id_bits);
+}
+
+static void gicv5_its_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
+{
+	u64 addr;
+	struct gicv5_its_dev *its_dev = irq_data_get_irq_chip_data(d);
+	struct gicv5_its_chip_data *its = its_dev->its_node;
+
+	addr = its->its_trans_phys_base;
+
+	msg->data = FIELD_GET(GICV5_ITS_HWIRQ_EVENT_ID, d->hwirq);
+	msi_msg_set_addr(irq_data_get_msi_desc(d), msg, addr);
+}
+
+static const struct irq_chip gicv5_its_irq_chip = {
+	.name			= "GICv5-ITS-MSI",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_get_irqchip_state	= irq_chip_get_parent_state,
+	.irq_set_irqchip_state	= irq_chip_set_parent_state,
+	.irq_compose_msi_msg	= gicv5_its_compose_msi_msg,
+	.flags			= IRQCHIP_SET_TYPE_MASKED |
+				  IRQCHIP_SKIP_SET_WAKE	  |
+				  IRQCHIP_MASK_ON_SUSPEND
+};
+
+static struct gicv5_its_dev *gicv5_its_find_device(
+				struct gicv5_its_chip_data *its, u32 device_id)
+{
+	struct gicv5_its_dev *dev = xa_load(&its->its_devices, device_id);
+
+	return dev ? dev : ERR_PTR(-ENODEV);
+}
+
+static struct gicv5_its_dev *gicv5_its_alloc_device(
+				struct gicv5_its_chip_data *its, int nvec,
+				u32 dev_id)
+{
+	int ret;
+	struct gicv5_its_dev *its_dev;
+
+	its_dev = gicv5_its_find_device(its, dev_id);
+	if (!IS_ERR(its_dev)) {
+		pr_debug("A device with this DeviceID (0x%x) has already been registered.\n",
+			dev_id);
+
+		if (nvec > its_dev->num_events) {
+			pr_debug("Requesting more ITT entries than allocated\n");
+			return ERR_PTR(-ENXIO);
+		}
+
+		its_dev->shared = true;
+
+		return its_dev;
+	}
+
+	its_dev = kzalloc(sizeof(*its_dev), GFP_KERNEL);
+	if (!its_dev)
+		return ERR_PTR(-ENOMEM);
+
+	its_dev->device_id = dev_id;
+	its_dev->num_events = nvec;
+	its_dev->num_mapped_events = 0;
+
+	ret = gicv5_its_device_register(its, its_dev);
+	if (ret) {
+		pr_debug("Failed to register the device\n");
+		kfree(its_dev);
+		return ERR_PTR(ret);
+	}
+
+	gicv5_its_device_cache_inv(its, its_dev);
+
+	/*
+	 * This is the first time we have seen this device. Hence, it is not
+	 * shared.
+	 */
+	its_dev->shared = false;
+
+	its_dev->its_node = its;
+
+	its_dev->event_map =
+		(unsigned long *)bitmap_zalloc(its_dev->num_events, GFP_KERNEL);
+	if (!its_dev->event_map) {
+		gicv5_its_device_unregister(its, its_dev);
+		kfree(its_dev);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	xa_store(&its->its_devices, dev_id, its_dev, GFP_KERNEL);
+
+	return its_dev;
+}
+
+static int gicv5_its_msi_prepare(struct irq_domain *domain, struct device *dev,
+				 int nvec, msi_alloc_info_t *info)
+{
+	struct msi_domain_info *msi_info;
+	struct gicv5_its_chip_data *its;
+	struct gicv5_its_dev *its_dev;
+	u32 dev_id = info->scratchpad[0].ul;
+
+	msi_info = msi_get_domain_info(domain);
+	its = msi_info->data;
+
+	guard(mutex)(&its->dev_alloc_lock);
+
+	its_dev = gicv5_its_alloc_device(its, nvec, dev_id);
+	if (IS_ERR(its_dev))
+		return PTR_ERR(its_dev);
+
+	if (info->flags & MSI_ALLOC_FLAGS_PROXY_DEVICE)
+		its_dev->shared = true;
+
+	return 0;
+}
+
+static struct msi_domain_ops its_msi_domain_ops = {
+	.msi_prepare = gicv5_its_msi_prepare,
+};
+
+static int gicv5_its_alloc_event(struct gicv5_its_dev *its_dev, u16 event_id,
+				 u32 lpi)
+{
+	int ret;
+	__le64 *itte;
+	u64 itt_entry;
+	struct gicv5_its_chip_data *its = its_dev->its_node;
+
+	if (event_id >= its_dev->num_events) {
+		pr_debug("EventID 0x%x outside of ITT range (0x%x)\n", event_id,
+		       its_dev->num_events);
+		return -EINVAL;
+	}
+
+	if (WARN(its_dev->num_mapped_events == its_dev->num_events,
+		"Reached maximum number of events\n"))
+		return -EINVAL;
+
+	ret = gicv5_its_device_get_itte_ref(its_dev, &itte, event_id);
+	if (ret)
+		return ret;
+
+	if (FIELD_GET(GICV5_ITTL2E_VALID, *itte))
+		return -EEXIST;
+
+	itt_entry = FIELD_PREP(GICV5_ITTL2E_LPI_ID, lpi) |
+		    FIELD_PREP(GICV5_ITTL2E_VALID, 0x1);
+
+	its_write_table_entry(its, itte, cpu_to_le64(itt_entry));
+
+	gicv5_its_itt_cache_inv(its, its_dev->device_id, event_id);
+
+	its_dev->num_mapped_events += 1;
+
+	return 0;
+}
+
+static void gicv5_its_free_event(struct gicv5_its_dev *its_dev, u16 event_id)
+{
+	int ret;
+	__le64 *itte;
+	u64 itte_val;
+	struct gicv5_its_chip_data *its = its_dev->its_node;
+
+	if (WARN(!its_dev->num_mapped_events, "No mapped events\n"))
+		return;
+
+	ret = gicv5_its_device_get_itte_ref(its_dev, &itte, event_id);
+	if (ret) {
+		pr_debug("Failed to get the ITTE!\n");
+		return;
+	}
+
+	itte_val = le64_to_cpu(*itte);
+	itte_val &= ~GICV5_ITTL2E_VALID;
+
+	its_write_table_entry(its, itte, cpu_to_le64(itte_val));
+
+	gicv5_its_itt_cache_inv(its, its_dev->device_id, event_id);
+
+	its_dev->num_mapped_events -= 1;
+}
+
+static int gicv5_its_alloc_eventid(struct gicv5_its_dev *its_dev,
+				   unsigned int nr_irqs, u32 *eventid)
+{
+	int ret;
+
+	ret = bitmap_find_free_region(its_dev->event_map,
+				      its_dev->num_events,
+				      get_count_order(nr_irqs));
+
+	if (ret < 0)
+		return ret;
+
+	*eventid = ret;
+
+	return 0;
+}
+
+static void gicv5_its_free_eventid(struct gicv5_its_dev *its_dev,
+				   u32 event_id_base,
+				   unsigned int nr_irqs)
+{
+	bitmap_release_region(its_dev->event_map, event_id_base,
+				      get_count_order(nr_irqs));
+}
+
+static int gicv5_its_irq_domain_alloc(struct irq_domain *domain,
+				      unsigned int virq, unsigned int nr_irqs,
+				      void *arg)
+{
+	int ret, i;
+	irq_hw_number_t hwirq;
+	struct irq_data *irqd;
+	struct gicv5_its_dev *its_dev;
+	struct gicv5_its_chip_data *its;
+	u32 event_id_base, lpi_base, lpi;
+	struct msi_domain_info *msi_info;
+	msi_alloc_info_t *info = arg;
+	unsigned long device_id = info->scratchpad[0].ul;
+
+	msi_info = msi_get_domain_info(domain);
+	its = msi_info->data;
+
+	guard(mutex)(&its->dev_alloc_lock);
+
+	its_dev = gicv5_its_find_device(its, device_id);
+	if (IS_ERR(its_dev))
+		return PTR_ERR(its_dev);
+
+	ret = gicv5_its_alloc_eventid(its_dev, nr_irqs, &event_id_base);
+	if (ret)
+		return ret;
+
+	ret = iommu_dma_prepare_msi(info->desc,
+				    its->its_trans_phys_base);
+	if (ret)
+		goto out_eventid;
+
+	ret = gicv5_alloc_lpi_range(nr_irqs, &lpi_base);
+	if (ret) {
+		pr_debug("Failed to find free LPIs!\n");
+		goto out_eventid;
+	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		lpi = lpi_base + i;
+
+		ret = irq_domain_alloc_irqs_parent(domain, virq + i, 1, &lpi);
+		if (ret)
+			goto out_free_lpi;
+
+		/*
+		 * Store eventid and deviceid into the hwirq for later use.
+		 *
+		 *	hwirq  = event_id << 32 | device_id
+		 */
+		hwirq = FIELD_PREP(GICV5_ITS_HWIRQ_DEVICE_ID, device_id) |
+			FIELD_PREP(GICV5_ITS_HWIRQ_EVENT_ID,
+				    (u64)event_id_base + i);
+		irq_domain_set_info(domain, virq + i, hwirq,
+				    &gicv5_its_irq_chip, its_dev,
+				    handle_fasteoi_irq, NULL, NULL);
+
+		irqd = irq_get_irq_data(virq + i);
+		irqd_set_single_target(irqd);
+		irqd_set_affinity_on_activate(irqd);
+		irqd_set_resend_when_in_progress(irqd);
+	}
+
+	return 0;
+
+out_free_lpi:
+	gicv5_free_lpi_range(lpi_base, nr_irqs);
+out_eventid:
+	gicv5_its_free_eventid(its_dev, event_id_base, nr_irqs);
+
+	return ret;
+}
+
+static void gicv5_its_irq_domain_free(struct irq_domain *domain,
+				      unsigned int virq, unsigned int nr_irqs)
+{
+	int i;
+	u16 event_id_base;
+	u32 device_id;
+	bool free_device;
+	struct irq_data *d;
+	struct gicv5_its_dev *its_dev;
+	struct msi_domain_info *msi_info;
+	struct gicv5_its_chip_data *its;
+
+	msi_info = msi_get_domain_info(domain);
+	its = msi_info->data;
+
+	d = irq_domain_get_irq_data(domain, virq);
+	device_id = FIELD_GET(GICV5_ITS_HWIRQ_DEVICE_ID, d->hwirq);
+	event_id_base = FIELD_GET(GICV5_ITS_HWIRQ_EVENT_ID, d->hwirq);
+
+	guard(mutex)(&its->dev_alloc_lock);
+
+	its_dev = gicv5_its_find_device(its, device_id);
+	if (IS_ERR(its_dev)) {
+		pr_debug("Couldn't find the ITS device!\n");
+		return;
+	}
+
+	bitmap_release_region(its_dev->event_map, event_id_base,
+			      get_count_order(nr_irqs));
+
+	free_device = !its_dev->shared && bitmap_empty(its_dev->event_map,
+						       its_dev->num_events);
+
+	/*  Hierarchically free irq data */
+	for (i = 0; i < nr_irqs; i++) {
+		d = irq_domain_get_irq_data(domain, virq + i);
+
+		WARN_ON(gicv5_free_lpi_range(d->parent_data->hwirq, 1));
+		irq_domain_reset_irq_data(d);
+	}
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+
+	gicv5_its_syncr(its, its_dev);
+	gicv5_irs_syncr();
+
+	if (free_device) {
+		gicv5_its_device_unregister(its, its_dev);
+		bitmap_free(its_dev->event_map);
+		xa_erase(&its->its_devices, device_id);
+		kfree(its_dev);
+	}
+}
+
+static int gicv5_its_irq_domain_activate(struct irq_domain *domain,
+					 struct irq_data *d, bool reserve)
+{
+	u16 event_id;
+	u32 lpi;
+	struct gicv5_its_dev *its_dev = irq_data_get_irq_chip_data(d);
+
+	event_id = FIELD_GET(GICV5_ITS_HWIRQ_EVENT_ID, d->hwirq);
+	lpi = d->parent_data->hwirq;
+
+	return gicv5_its_alloc_event(its_dev, event_id, lpi);
+}
+
+static void gicv5_its_irq_domain_deactivate(struct irq_domain *domain,
+					    struct irq_data *d)
+{
+	u16 event_id;
+	struct gicv5_its_dev *its_dev = irq_data_get_irq_chip_data(d);
+
+	event_id = FIELD_GET(GICV5_ITS_HWIRQ_EVENT_ID, d->hwirq);
+
+	gicv5_its_free_event(its_dev, event_id);
+}
+static const struct irq_domain_ops gicv5_its_irq_domain_ops = {
+	.alloc		= gicv5_its_irq_domain_alloc,
+	.free		= gicv5_its_irq_domain_free,
+	.activate	= gicv5_its_irq_domain_activate,
+	.deactivate	= gicv5_its_irq_domain_deactivate,
+	.select		= msi_lib_irq_domain_select,
+};
+
+static int gicv5_its_wait_for_idle(struct gicv5_its_chip_data *its)
+{
+	int ret;
+	u32 cr0;
+
+	ret = readl_relaxed_poll_timeout_atomic(
+			its->its_base + GICV5_ITS_CR0, cr0,
+			FIELD_GET(GICV5_ITS_CR0_IDLE, cr0), 1,
+			USEC_PER_SEC);
+
+	if (ret == -ETIMEDOUT)
+		pr_err_ratelimited("GICv5 ITS CR0 timeout...\n");
+
+	return ret;
+}
+
+static void gicv5_its_print_info(struct gicv5_its_chip_data *its_node)
+{
+	u8 str;
+	bool devtab_linear;
+	u8 device_id_bits = FIELD_GET(GICV5_ITS_DT_CFGR_DEVICEID_BITS,
+			    its_node->devtab_cfgr.cfgr);
+
+	str = FIELD_GET(GICV5_ITS_DT_CFGR_STRUCTURE, its_node->devtab_cfgr.cfgr);
+	devtab_linear = (str == GICV5_ITS_DT_ITT_CFGR_STRUCTURE_LINEAR);
+
+	pr_info("ITS %s enabled using %s device table device_id_bits %u\n",
+		fwnode_get_name(its_node->fwnode),
+		devtab_linear ? "linear" : "2-level",
+		device_id_bits);
+}
+
+static int __init gicv5_its_init_bases(phys_addr_t its_trans_base,
+				       void __iomem *its_base,
+				       struct fwnode_handle *handle,
+				       struct irq_domain *parent_domain)
+
+{
+	int ret;
+	bool enabled;
+	u32 cr0, cr1;
+	struct gicv5_its_chip_data *its_node;
+	struct msi_domain_info *info;
+	struct device_node *np = to_of_node(handle);
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	its_node = kzalloc(sizeof(*its_node), GFP_KERNEL);
+	if (!its_node) {
+		kfree(info);
+		return -ENOMEM;
+	}
+
+	info->ops = &its_msi_domain_ops;
+	info->data = its_node;
+
+	mutex_init(&its_node->dev_alloc_lock);
+	xa_init(&its_node->its_devices);
+	its_node->fwnode = handle;
+	its_node->its_base = its_base;
+	its_node->its_trans_phys_base = its_trans_base;
+
+	its_node->domain = irq_domain_create_hierarchy(
+		parent_domain, IRQ_DOMAIN_FLAG_ISOLATED_MSI, 0, handle,
+		&gicv5_its_irq_domain_ops, info);
+	irq_domain_update_bus_token(its_node->domain,
+				    DOMAIN_BUS_NEXUS);
+
+	its_node->domain->msi_parent_ops = &gic_its_msi_parent_ops;
+	its_node->domain->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT;
+
+	cr0 = its_readl(its_node, GICV5_ITS_CR0);
+	enabled = FIELD_GET(GICV5_ITS_CR0_ITSEN, cr0);
+	if (WARN(enabled, "ITS %s enabled, disabling it before proceeding\n",
+		 np->full_name)) {
+		cr0 = FIELD_PREP(GICV5_ITS_CR0_ITSEN, 0x0);
+		its_writel(its_node, cr0, GICV5_ITS_CR0);
+		ret = gicv5_its_wait_for_idle(its_node);
+		if (ret) {
+			irq_domain_remove(its_node->domain);
+			kfree(info);
+			kfree(its_node);
+			return ret;
+		}
+	}
+
+	if (of_property_read_bool(np, "dma-noncoherent")) {
+		/*
+		 * A non-coherent ITS implies that some cache levels cannot be
+		 * used coherently by the cores and GIC. Our only option is to mark
+		 * memory attributes for the GIC as non-cacheable; by default,
+		 * non-cacheable memory attributes imply outer-shareable
+		 * shareability, the value written into ITS_CR1_SH is ignored.
+		 */
+		cr1 = FIELD_PREP(GICV5_ITS_CR1_ITT_RA, GICV5_NO_READ_ALLOC)	|
+		      FIELD_PREP(GICV5_ITS_CR1_DT_RA, GICV5_NO_READ_ALLOC)	|
+		      FIELD_PREP(GICV5_ITS_CR1_IC, GICV5_NON_CACHE)		|
+		      FIELD_PREP(GICV5_ITS_CR1_OC, GICV5_NON_CACHE);
+		its_node->flags |= ITS_FLAGS_NON_COHERENT;
+	} else {
+		cr1 = FIELD_PREP(GICV5_ITS_CR1_ITT_RA, GICV5_READ_ALLOC)	|
+		      FIELD_PREP(GICV5_ITS_CR1_DT_RA, GICV5_READ_ALLOC)		|
+		      FIELD_PREP(GICV5_ITS_CR1_IC, GICV5_WB_CACHE)		|
+		      FIELD_PREP(GICV5_ITS_CR1_OC, GICV5_WB_CACHE)		|
+		      FIELD_PREP(GICV5_ITS_CR1_SH, GICV5_INNER_SHARE);
+	}
+
+	its_writel(its_node, cr1, GICV5_ITS_CR1);
+
+	ret = gicv5_its_init_devtab(its_node);
+	if (ret) {
+		irq_domain_remove(its_node->domain);
+		kfree(info);
+		kfree(its_node);
+		return ret;
+	}
+
+	cr0 = FIELD_PREP(GICV5_ITS_CR0_ITSEN, 0x1);
+	its_writel(its_node, cr0, GICV5_ITS_CR0);
+
+	ret = gicv5_its_wait_for_idle(its_node);
+	if (ret) {
+		irq_domain_remove(its_node->domain);
+		kfree(info);
+		kfree(its_node);
+		return ret;
+	}
+
+	list_add(&its_node->entry, &its_nodes);
+
+	gicv5_its_print_info(its_node);
+
+	return 0;
+}
+
+static int __init gicv5_its_init(struct device_node *node)
+{
+	int ret = 0;
+	void __iomem *its_base;
+	struct resource res;
+
+	its_base = of_io_request_and_map(node, 0, "ITS");
+	if (IS_ERR(its_base)) {
+		pr_err("%pOF: unable to map GICv5 ITS_CONFIG_FRAME\n", node);
+		return PTR_ERR(its_base);
+	}
+
+	/*
+	 * The ITS_TRANSLATE_FRAME is the second reg entry, (first is the
+	 * ITS_CONFIG_FRAME) - extract it and use it to init ITS data
+	 * structures.
+	 */
+	ret = of_address_to_resource(node, 1, &res);
+	if (ret)
+		goto out_unmap;
+
+	ret = gicv5_its_init_bases(res.start, its_base, &node->fwnode,
+				   gicv5_global_data.lpi_domain);
+	if (ret)
+		goto out_unmap;
+
+	return 0;
+out_unmap:
+	iounmap(its_base);
+	return ret;
+}
+
+void __init gicv5_its_of_probe(struct device_node *parent)
+{
+	struct device_node *np;
+
+	for_each_available_child_of_node(parent, np) {
+		if (!of_device_is_compatible(np, "arm,gic-v5-its"))
+			continue;
+
+		if (gicv5_its_init(np))
+			pr_err("Failed to init ITS %s\n", np->full_name);
+	}
+}
diff --git a/drivers/irqchip/irq-gic-v5.c b/drivers/irqchip/irq-gic-v5.c
index 24789e9590115e6de7007cd4a74376ae34702ed6..13145d8b0a038b7c13fee32a3b1bc235029e38f1 100644
--- a/drivers/irqchip/irq-gic-v5.c
+++ b/drivers/irqchip/irq-gic-v5.c
@@ -100,12 +100,12 @@  static int release_lpi_range(u32 min, u32 max)
 	return mtree_store_range(&lpi_mt, min, max, NULL, GFP_KERNEL);
 }
 
-static int gicv5_alloc_lpi_range(u32 nr_lpis, u32 *base)
+int gicv5_alloc_lpi_range(u32 nr_lpis, u32 *base)
 {
 	return alloc_lpi_range(nr_lpis, base);
 }
 
-static int gicv5_free_lpi_range(u32 base, u32 nr_lpis)
+int gicv5_free_lpi_range(u32 base, u32 nr_lpis)
 {
 	if (nr_lpis < 1)
 		return -EINVAL;
@@ -1217,6 +1217,8 @@  static int __init gicv5_of_init(struct device_node *node,
 
 	gicv5_smp_init();
 
+	gicv5_irs_its_probe();
+
 	return 0;
 }
 IRQCHIP_DECLARE(gic_v5, "arm,gic-v5", gicv5_of_init);
diff --git a/drivers/irqchip/irq-gic-v5.h b/drivers/irqchip/irq-gic-v5.h
index 8376da2a342d14568a71c0bc85b79c4e7b83a66c..b5c3f69305f30dfa6332fd50c0b98300e3484a05 100644
--- a/drivers/irqchip/irq-gic-v5.h
+++ b/drivers/irqchip/irq-gic-v5.h
@@ -41,6 +41,8 @@ 
 #define GICV5_IRS_IDR7			0x001c
 #define GICV5_IRS_CR0			0x0080
 #define GICV5_IRS_CR1			0x0084
+#define GICV5_IRS_SYNCR			0x00c0
+#define GICV5_IRS_SYNC_STATUSR		0x00c4
 #define GICV5_IRS_SPI_SELR		0x0108
 #define GICV5_IRS_SPI_CFGR		0x0114
 #define GICV5_IRS_SPI_STATUSR		0x0118
@@ -94,6 +96,10 @@ 
 #define GICV5_IRS_CR1_OC		GENMASK(3, 2)
 #define GICV5_IRS_CR1_SH		GENMASK(1, 0)
 
+#define GICV5_IRS_SYNCR_SYNC		BIT(31)
+
+#define GICV5_IRS_SYNC_STATUSR_IDLE	BIT(0)
+
 #define GICV5_IRS_SPI_STATUSR_V		BIT(1)
 #define GICV5_IRS_SPI_STATUSR_IDLE	BIT(0)
 
@@ -135,6 +141,101 @@ 
 
 #define GICV5_ISTL1E_L2_ADDR_MASK	GENMASK_ULL(55, 12)
 
+#define GICV5_ITS_IDR1		0x0004
+#define GICV5_ITS_IDR2		0x0008
+#define GICV5_ITS_CR0		0x0080
+#define GICV5_ITS_CR1		0x0084
+#define GICV5_ITS_DT_BASER	0x00c0
+#define GICV5_ITS_DT_CFGR	0x00d0
+#define GICV5_ITS_DIDR		0x0100
+#define GICV5_ITS_EIDR		0x0108
+#define GICV5_ITS_INV_EVENTR	0x010c
+#define GICV5_ITS_INV_DEVICER	0x0110
+#define GICV5_ITS_STATUSR	0x0120
+#define GICV5_ITS_SYNCR		0x0140
+#define GICV5_ITS_SYNC_STATUSR	0x0148
+
+#define GICV5_ITS_IDR1_L2SZ			GENMASK(10, 8)
+#define GICV5_ITS_IDR1_ITT_LEVELS		BIT(7)
+#define GICV5_ITS_IDR1_DT_LEVELS		BIT(6)
+#define GICV5_ITS_IDR1_DEVICEID_BITS		GENMASK(5, 0)
+
+#define GICV5_ITS_IDR1_L2SZ_SUPPORT_4KB(r)	FIELD_GET(BIT(8), (r))
+#define GICV5_ITS_IDR1_L2SZ_SUPPORT_16KB(r)	FIELD_GET(BIT(9), (r))
+#define GICV5_ITS_IDR1_L2SZ_SUPPORT_64KB(r)	FIELD_GET(BIT(10), (r))
+
+#define GICV5_ITS_IDR2_XDMN_EVENTs		GENMASK(6, 5)
+#define GICV5_ITS_IDR2_EVENTID_BITS		GENMASK(4, 0)
+
+#define GICV5_ITS_CR0_IDLE			BIT(1)
+#define GICV5_ITS_CR0_ITSEN			BIT(0)
+
+#define GICV5_ITS_CR1_ITT_RA			BIT(7)
+#define GICV5_ITS_CR1_DT_RA			BIT(6)
+#define GICV5_ITS_CR1_IC			GENMASK(5, 4)
+#define GICV5_ITS_CR1_OC			GENMASK(3, 2)
+#define GICV5_ITS_CR1_SH			GENMASK(1, 0)
+
+#define GICV5_ITS_DT_CFGR_STRUCTURE		BIT(16)
+#define GICV5_ITS_DT_CFGR_L2SZ			GENMASK(7, 6)
+#define GICV5_ITS_DT_CFGR_DEVICEID_BITS		GENMASK(5, 0)
+
+#define GICV5_ITS_DT_BASER_ADDR_MASK		GENMASK_ULL(55, 3)
+
+#define GICV5_ITS_INV_DEVICER_I			BIT(31)
+#define GICV5_ITS_INV_DEVICER_EVENTID_BITS	GENMASK(5, 1)
+#define GICV5_ITS_INV_DEVICER_L1		BIT(0)
+
+#define GICV5_ITS_DIDR_DEVICEID			GENMASK_ULL(31, 0)
+
+#define GICV5_ITS_EIDR_EVENTID			GENMASK(15, 0)
+
+#define GICV5_ITS_INV_EVENTR_I			BIT(31)
+#define GICV5_ITS_INV_EVENTR_ITT_L2SZ		GENMASK(2, 1)
+#define GICV5_ITS_INV_EVENTR_L1			BIT(0)
+
+#define GICV5_ITS_STATUSR_IDLE			BIT(0)
+
+#define GICV5_ITS_SYNCR_SYNC			BIT_ULL(63)
+#define GICV5_ITS_SYNCR_SYNCALL			BIT_ULL(32)
+#define GICV5_ITS_SYNCR_DEVICEID		GENMASK_ULL(31, 0)
+
+#define GICV5_ITS_SYNC_STATUSR_IDLE		BIT(0)
+
+#define GICV5_DTL1E_VALID			BIT_ULL(0)
+// Note that there is no shift for the address by design
+#define GICV5_DTL1E_L2_ADDR_MASK		GENMASK_ULL(55, 3)
+#define GICV5_DTL1E_SPAN			GENMASK_ULL(63, 60)
+
+#define GICV5_DTL2E_VALID			BIT_ULL(0)
+#define GICV5_DTL2E_ITT_L2SZ			GENMASK_ULL(2, 1)
+// Note that there is no shift for the address by design
+#define GICV5_DTL2E_ITT_ADDR_MASK		GENMASK_ULL(55, 3)
+#define GICV5_DTL2E_ITT_DSWE			BIT_ULL(57)
+#define GICV5_DTL2E_ITT_STRUCTURE		BIT_ULL(58)
+#define GICV5_DTL2E_EVENT_ID_BITS		GENMASK_ULL(63, 59)
+
+#define GICV5_ITTL1E_VALID			BIT_ULL(0)
+// Note that there is no shift for the address by design
+#define GICV5_ITTL1E_L2_ADDR_MASK		GENMASK_ULL(55, 3)
+#define GICV5_ITTL1E_SPAN			GENMASK_ULL(63, 60)
+
+#define GICV5_ITTL2E_LPI_ID			GENMASK_ULL(23, 0)
+#define GICV5_ITTL2E_DAC			GENMASK_ULL(29, 28)
+#define GICV5_ITTL2E_VIRTUAL			BIT_ULL(30)
+#define GICV5_ITTL2E_VALID			BIT_ULL(31)
+#define GICV5_ITTL2E_VM_ID			GENMASK_ULL(47, 32)
+
+#define GICV5_ITS_DT_ITT_CFGR_L2SZ_4k		0b00
+#define GICV5_ITS_DT_ITT_CFGR_L2SZ_16k		0b01
+#define GICV5_ITS_DT_ITT_CFGR_L2SZ_64k		0b10
+
+#define GICV5_ITS_DT_ITT_CFGR_STRUCTURE_LINEAR		0
+#define GICV5_ITS_DT_ITT_CFGR_STRUCTURE_TWO_LEVEL	1
+
+#define GICV5_ITS_HWIRQ_DEVICE_ID		GENMASK_ULL(31, 0)
+#define GICV5_ITS_HWIRQ_EVENT_ID		GENMASK_ULL(63, 32)
+
 struct gicv5_chip_data {
 	struct fwnode_handle	*fwnode;
 	struct irq_domain	*ppi_domain;
@@ -172,13 +273,72 @@  void __init gicv5_free_lpi_domain(void);
 int gicv5_irs_of_probe(struct device_node *parent);
 void gicv5_irs_remove(void);
 int gicv5_irs_enable(void);
+void gicv5_irs_its_probe(void);
 int gicv5_irs_register_cpu(int cpuid);
 int gicv5_irs_cpu_to_iaffid(int cpu_id, u16 *iaffid);
 struct gicv5_irs_chip_data *gicv5_irs_lookup_by_spi_id(u32 spi_id);
 int gicv5_spi_irq_set_type(struct irq_data *d, unsigned int type);
 int gicv5_spi_set_type(struct irq_data *d, unsigned int type);
 int gicv5_irs_iste_alloc(u32 lpi);
+void gicv5_irs_syncr(void);
+
+struct gicv5_its_devtab_cfg {
+	union {
+		struct {
+			__le64	*devtab;
+		} linear;
+		struct {
+			__le64	*l1devtab;
+			__le64	**l2ptrs;
+		} l2;
+	};
+	u32	cfgr;
+};
+
+struct gicv5_its_itt_cfg {
+	union {
+		struct {
+			__le64	*itt;
+			unsigned int num_ents;
+		} linear;
+		struct {
+			__le64	*l1itt;
+			__le64	**l2ptrs;
+			unsigned int num_l1_ents;
+			u8 l2sz;
+		} l2;
+	};
+	u8 event_id_bits;
+	bool l2itt;
+};
+
+struct gicv5_its_chip_data {
+	struct	list_head		entry;
+	struct	xarray			its_devices;
+	struct	mutex			dev_alloc_lock;
+	struct	fwnode_handle		*fwnode;
+	struct gicv5_its_devtab_cfg	devtab_cfgr;
+	struct irq_domain		*domain;
+	void	__iomem			*its_base;
+	phys_addr_t			its_trans_phys_base;
+	u32				flags;
+};
+
+struct gicv5_its_dev {
+	struct gicv5_its_chip_data	*its_node;
+	struct gicv5_its_itt_cfg	itt_cfg;
+	unsigned long			*event_map;
+	u32				device_id;
+	u32				num_events;
+	u32				num_mapped_events;
+	bool				shared;
+};
 
 void gicv5_init_lpi(u32 max);
 void gicv5_free_lpi(void);
+
+int gicv5_alloc_lpi_range(u32 nr_lpis, u32 *base);
+int gicv5_free_lpi_range(u32 base, u32 nr_lpis);
+
+void __init gicv5_its_of_probe(struct device_node *parent);
 #endif