[PATCH v2 0/9] Level-triggered MSI support

[PATCH v2 0/9] Level-triggered MSI support

[Marc Zyngier]

This series is a first shot at teaching the kernel about the oxymoron
expressed in $SUBJECT. Over the past couple of years, we've seen some
SoCs coming up with ways of signalling level interrupts using a new
flavor of MSIs, where the MSI controller uses two distinct messages:
one that raises a virtual line, and one that lowers it. The target MSI
controller is in charge of maintaining the state of the line.

This allows for a much simplified HW signal routing (no need to have
hundreds of discrete lines to signal level interrupts if you already
have a memory bus), but results in a departure from the current idea
the kernel has of MSIs.

This series takes a minimal approach to the problem, which is to allow
MSI controllers to use not only one, but up to two messages at a
time. This is controlled by a flag exposed at MSI irq domain creation,
and is only supported with platform MSI.

The rest of the series repaints the Marvell ICU/GICP drivers which
already make use of this feature with a side-channel, and adds support
for the same feature in GICv3. A side effect of the last GICv3 patch
is that you can also use SPIs to signal PCI MSIs. This is a last
resort measure for SoCs where the ITS is unusable for unspeakable
reasons.

* From v1:
  - irq_find_host now defaults to DOMAIN_BUS_WIRED
  - Introduced a new irqchip flag indicating support for Level MSI
  - Turned GICv3 MBI allocator spinlock into a mutex
  - Exclude fsl-mc from Level MSI

Marc Zyngier (9):
  genirq/msi: Allow level-triggered MSIs to be exposed by MSI providers
  genirq/msi: Limit level-triggered MSI to platform devices
  irqchip/mvebu-gicp: Use level-triggered MSIs between ICU and GICP
  dma-iommu: Fix compilation when !CONFIG_IOMMU_DMA
  irqdomain: Let irq_find_host default to DOMAIN_BUS_WIRED
  irqchip/gic-v3: Mark the base irq domain as DOMAIN_BUS_WIRED
  irqchip/gic-v3: Add support for Message Based Interrupts as an MSI
    controller
  irqchip/gic-v3: Add PCI/MSI support to the GICv3 MBI sub-driver
  dt-bindings/gic-v3: Add documentation for MBI support

 .../bindings/interrupt-controller/arm,gic-v3.txt   |  17 ++
 drivers/base/platform-msi.c                        |   3 +
 drivers/bus/fsl-mc/fsl-mc-msi.c                    |   2 +
 drivers/irqchip/Makefile                           |   2 +-
 drivers/irqchip/irq-gic-v3-mbi.c                   | 331 +++++++++++++++++++++
 drivers/irqchip/irq-gic-v3.c                       |   7 +
 drivers/irqchip/irq-mvebu-gicp.c                   |  38 +--
 drivers/irqchip/irq-mvebu-gicp.h                   |  12 -
 drivers/irqchip/irq-mvebu-icu.c                    |  33 +-
 drivers/pci/msi.c                                  |   3 +
 include/linux/dma-iommu.h                          |   1 +
 include/linux/irq.h                                |   1 +
 include/linux/irqchip/arm-gic-v3.h                 |   1 +
 include/linux/irqdomain.h                          |   8 +-
 include/linux/msi.h                                |   2 +
 kernel/irq/msi.c                                   |  33 +-
 16 files changed, 428 insertions(+), 66 deletions(-)
 create mode 100644 drivers/irqchip/irq-gic-v3-mbi.c
 delete mode 100644 drivers/irqchip/irq-mvebu-gicp.h

-- 
2.14.2

[PATCH v2 1/9] genirq/msi: Allow level-triggered MSIs to be exposed by MSI providers

[Marc Zyngier]

So far, MSIs have been used to signal edge-triggered interrupts, as
a write is a good model for an edge (you can't "unwrite" something).
On the other hand, routing zillions of wires in an SoC because you
need level interrupts is a bit extreme.

People have come up with a variety of schemes to support this, which
involves sending two messages: one to signal the interrupt, and one
to clear it. Since the kernel cannot represent this, we've ended up
with side-band mechanisms that are pretty awful.

Instead, let's acknoledge the requirement, and ensure that, under the
right circumstances, the irq_compose_msg and irq_write_msg can take
as a parameter an array of two messages instead of a pointer to a
single one. We also add some checking that the compose method only
clobbers the second message if the MSI domain has been created with
the MSI_FLAG_LEVEL_CAPABLE flags.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 include/linux/msi.h |  2 ++
 kernel/irq/msi.c    | 33 ++++++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 1f1bbb5b4679..5839d8062dfc 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -289,6 +289,8 @@ enum {
 	 * MSI_FLAG_ACTIVATE_EARLY has been set.
 	 */
 	MSI_FLAG_MUST_REACTIVATE	= (1 << 5),
+	/* Is level-triggered capable, using two messages */
+	MSI_FLAG_LEVEL_CAPABLE		= (1 << 6),
 };
 
 int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 2a8571f72b17..4ca2fd46645d 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -76,6 +76,19 @@ static inline void irq_chip_write_msi_msg(struct irq_data *data,
 	data->chip->irq_write_msi_msg(data, msg);
 }
 
+static void msi_check_level(struct irq_domain *domain, struct msi_msg *msg)
+{
+	struct msi_domain_info *info = domain->host_data;
+
+	/*
+	 * If the MSI provider has messed with the second message and
+	 * not advertized that it is level-capable, signal the breakage.
+	 */
+	WARN_ON(!((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
+		  (info->chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)) &&
+		(msg[1].address_lo || msg[1].address_hi || msg[1].data));
+}
+
 /**
  * msi_domain_set_affinity - Generic affinity setter function for MSI domains
  * @irq_data:	The irq data associated to the interrupt
@@ -89,13 +102,14 @@ int msi_domain_set_affinity(struct irq_data *irq_data,
 			    const struct cpumask *mask, bool force)
 {
 	struct irq_data *parent = irq_data->parent_data;
-	struct msi_msg msg;
+	struct msi_msg msg[2] = { [1] = { }, };
 	int ret;
 
 	ret = parent->chip->irq_set_affinity(parent, mask, force);
 	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
-		BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
-		irq_chip_write_msi_msg(irq_data, &msg);
+		BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
+		msi_check_level(irq_data->domain, msg);
+		irq_chip_write_msi_msg(irq_data, msg);
 	}
 
 	return ret;
@@ -104,20 +118,21 @@ int msi_domain_set_affinity(struct irq_data *irq_data,
 static int msi_domain_activate(struct irq_domain *domain,
 			       struct irq_data *irq_data, bool early)
 {
-	struct msi_msg msg;
+	struct msi_msg msg[2] = { [1] = { }, };
 
-	BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
-	irq_chip_write_msi_msg(irq_data, &msg);
+	BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
+	msi_check_level(irq_data->domain, msg);
+	irq_chip_write_msi_msg(irq_data, msg);
 	return 0;
 }
 
 static void msi_domain_deactivate(struct irq_domain *domain,
 				  struct irq_data *irq_data)
 {
-	struct msi_msg msg;
+	struct msi_msg msg[2];
 
-	memset(&msg, 0, sizeof(msg));
-	irq_chip_write_msi_msg(irq_data, &msg);
+	memset(msg, 0, sizeof(msg));
+	irq_chip_write_msi_msg(irq_data, msg);
 }
 
 static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
-- 
2.14.2

[PATCH v2 2/9] genirq/msi: Limit level-triggered MSI to platform devices

[Marc Zyngier]

Nobody would be insane enough to try and use level triggered
MSIs on PCI, but let's make sure it doesn't happen. Also,
let's mandate that the irqchip backing the platform MSI domain
is providing the IRQCHIP_SUPPORTS_LEVEL_MSI flag.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/base/platform-msi.c     | 3 +++
 drivers/bus/fsl-mc/fsl-mc-msi.c | 2 ++
 drivers/pci/msi.c               | 3 +++
 include/linux/irq.h             | 1 +
 4 files changed, 9 insertions(+)

diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index 8e22073aeeed..60d6cc618f1c 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -101,6 +101,9 @@ static void platform_msi_update_chip_ops(struct msi_domain_info *info)
 		chip->irq_set_affinity = msi_domain_set_affinity;
 	if (!chip->irq_write_msi_msg)
 		chip->irq_write_msi_msg = platform_msi_write_msg;
+	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
+		    !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
 }
 
 static void platform_msi_free_descs(struct device *dev, int base, int nvec)
diff --git a/drivers/bus/fsl-mc/fsl-mc-msi.c b/drivers/bus/fsl-mc/fsl-mc-msi.c
index ec35e255b496..8b9c66d7c4ff 100644
--- a/drivers/bus/fsl-mc/fsl-mc-msi.c
+++ b/drivers/bus/fsl-mc/fsl-mc-msi.c
@@ -163,6 +163,8 @@ struct irq_domain *fsl_mc_msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
+	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE)))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		fsl_mc_msi_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 30250631efe7..f45b74fcc059 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1434,6 +1434,9 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
+	if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
+
 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		pci_msi_domain_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 65916a305f3d..b2067083aa94 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -512,6 +512,7 @@ enum {
 	IRQCHIP_SKIP_SET_WAKE		= (1 <<  4),
 	IRQCHIP_ONESHOT_SAFE		= (1 <<  5),
 	IRQCHIP_EOI_THREADED		= (1 <<  6),
+	IRQCHIP_SUPPORTS_LEVEL_MSI	= (1 <<  7),
 };
 
 #include <linux/irqdesc.h>
-- 
2.14.2

[PATCH v2 3/9] irqchip/mvebu-gicp: Use level-triggered MSIs between ICU and GICP

[Marc Zyngier]

The ICU and GICP drivers are using an ugly side-band mechanism to
find out about the "clear" doorbell when using level interrupts.

Let's convert it to level-triggered MSIs, which result in a nice
cleanup.

Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-mvebu-gicp.c | 38 +++++++++++---------------------------
 drivers/irqchip/irq-mvebu-gicp.h | 12 ------------
 drivers/irqchip/irq-mvebu-icu.c  | 33 +++++++++++++++++----------------
 3 files changed, 28 insertions(+), 55 deletions(-)
 delete mode 100644 drivers/irqchip/irq-mvebu-gicp.h

diff --git a/drivers/irqchip/irq-mvebu-gicp.c b/drivers/irqchip/irq-mvebu-gicp.c
index 17a4a7b6cdbb..4e17f7081efc 100644
--- a/drivers/irqchip/irq-mvebu-gicp.c
+++ b/drivers/irqchip/irq-mvebu-gicp.c
@@ -19,8 +19,6 @@
 
 #include <dt-bindings/interrupt-controller/arm-gic.h>
 
-#include "irq-mvebu-gicp.h"
-
 #define GICP_SETSPI_NSR_OFFSET	0x0
 #define GICP_CLRSPI_NSR_OFFSET	0x8
 
@@ -55,34 +53,18 @@ static int gicp_idx_to_spi(struct mvebu_gicp *gicp, int idx)
 	return -EINVAL;
 }
 
-int mvebu_gicp_get_doorbells(struct device_node *dn, phys_addr_t *setspi,
-			     phys_addr_t *clrspi)
-{
-	struct platform_device *pdev;
-	struct mvebu_gicp *gicp;
-
-	pdev = of_find_device_by_node(dn);
-	if (!pdev)
-		return -ENODEV;
-
-	gicp = platform_get_drvdata(pdev);
-	if (!gicp)
-		return -ENODEV;
-
-	*setspi = gicp->res->start + GICP_SETSPI_NSR_OFFSET;
-	*clrspi = gicp->res->start + GICP_CLRSPI_NSR_OFFSET;
-
-	return 0;
-}
-
 static void gicp_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	struct mvebu_gicp *gicp = data->chip_data;
 	phys_addr_t setspi = gicp->res->start + GICP_SETSPI_NSR_OFFSET;
-
-	msg->data = data->hwirq;
-	msg->address_lo = lower_32_bits(setspi);
-	msg->address_hi = upper_32_bits(setspi);
+	phys_addr_t clrspi = gicp->res->start + GICP_CLRSPI_NSR_OFFSET;
+
+	msg[0].data = data->hwirq;
+	msg[0].address_lo = lower_32_bits(setspi);
+	msg[0].address_hi = upper_32_bits(setspi);
+	msg[1].data = data->hwirq;
+	msg[1].address_lo = lower_32_bits(clrspi);
+	msg[1].address_hi = upper_32_bits(clrspi);
 }
 
 static struct irq_chip gicp_irq_chip = {
@@ -170,13 +152,15 @@ static const struct irq_domain_ops gicp_domain_ops = {
 static struct irq_chip gicp_msi_irq_chip = {
 	.name		= "GICP",
 	.irq_set_type	= irq_chip_set_type_parent,
+	.flags		= IRQCHIP_SUPPORTS_LEVEL_MSI,
 };
 
 static struct msi_domain_ops gicp_msi_ops = {
 };
 
 static struct msi_domain_info gicp_msi_domain_info = {
-	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_LEVEL_CAPABLE),
 	.ops	= &gicp_msi_ops,
 	.chip	= &gicp_msi_irq_chip,
 };
diff --git a/drivers/irqchip/irq-mvebu-gicp.h b/drivers/irqchip/irq-mvebu-gicp.h
deleted file mode 100644
index eaa12fb72102..000000000000
--- a/drivers/irqchip/irq-mvebu-gicp.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __MVEBU_GICP_H__
-#define __MVEBU_GICP_H__
-
-#include <linux/types.h>
-
-struct device_node;
-
-int mvebu_gicp_get_doorbells(struct device_node *dn, phys_addr_t *setspi,
-			     phys_addr_t *clrspi);
-
-#endif /* __MVEBU_GICP_H__ */
diff --git a/drivers/irqchip/irq-mvebu-icu.c b/drivers/irqchip/irq-mvebu-icu.c
index e18c48d3a92e..13063339b416 100644
--- a/drivers/irqchip/irq-mvebu-icu.c
+++ b/drivers/irqchip/irq-mvebu-icu.c
@@ -21,8 +21,6 @@
 
 #include <dt-bindings/interrupt-controller/mvebu-icu.h>
 
-#include "irq-mvebu-gicp.h"
-
 /* ICU registers */
 #define ICU_SETSPI_NSR_AL	0x10
 #define ICU_SETSPI_NSR_AH	0x14
@@ -43,6 +41,7 @@ struct mvebu_icu {
 	void __iomem *base;
 	struct irq_domain *domain;
 	struct device *dev;
+	atomic_t initialized;
 };
 
 struct mvebu_icu_irq_data {
@@ -51,6 +50,18 @@ struct mvebu_icu_irq_data {
 	unsigned int type;
 };
 
+static void mvebu_icu_init(struct mvebu_icu *icu, struct msi_msg *msg)
+{
+	if (atomic_cmpxchg(&icu->initialized, false, true))
+		return;
+
+	/* Set Clear/Set ICU SPI message address in AP */
+	writel_relaxed(msg[0].address_hi, icu->base + ICU_SETSPI_NSR_AH);
+	writel_relaxed(msg[0].address_lo, icu->base + ICU_SETSPI_NSR_AL);
+	writel_relaxed(msg[1].address_hi, icu->base + ICU_CLRSPI_NSR_AH);
+	writel_relaxed(msg[1].address_lo, icu->base + ICU_CLRSPI_NSR_AL);
+}
+
 static void mvebu_icu_write_msg(struct msi_desc *desc, struct msi_msg *msg)
 {
 	struct irq_data *d = irq_get_irq_data(desc->irq);
@@ -59,6 +70,8 @@ static void mvebu_icu_write_msg(struct msi_desc *desc, struct msi_msg *msg)
 	unsigned int icu_int;
 
 	if (msg->address_lo || msg->address_hi) {
+		/* One off initialization */
+		mvebu_icu_init(icu, msg);
 		/* Configure the ICU with irq number & type */
 		icu_int = msg->data | ICU_INT_ENABLE;
 		if (icu_irqd->type & IRQ_TYPE_EDGE_RISING)
@@ -197,9 +210,7 @@ static int mvebu_icu_probe(struct platform_device *pdev)
 	struct device_node *node = pdev->dev.of_node;
 	struct device_node *gicp_dn;
 	struct resource *res;
-	phys_addr_t setspi, clrspi;
-	u32 i, icu_int;
-	int ret;
+	int i;
 
 	icu = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_icu),
 			   GFP_KERNEL);
@@ -242,22 +253,12 @@ static int mvebu_icu_probe(struct platform_device *pdev)
 	if (!gicp_dn)
 		return -ENODEV;
 
-	ret = mvebu_gicp_get_doorbells(gicp_dn, &setspi, &clrspi);
-	if (ret)
-		return ret;
-
-	/* Set Clear/Set ICU SPI message address in AP */
-	writel_relaxed(upper_32_bits(setspi), icu->base + ICU_SETSPI_NSR_AH);
-	writel_relaxed(lower_32_bits(setspi), icu->base + ICU_SETSPI_NSR_AL);
-	writel_relaxed(upper_32_bits(clrspi), icu->base + ICU_CLRSPI_NSR_AH);
-	writel_relaxed(lower_32_bits(clrspi), icu->base + ICU_CLRSPI_NSR_AL);
-
 	/*
 	 * Clean all ICU interrupts with type SPI_NSR, required to
 	 * avoid unpredictable SPI assignments done by firmware.
 	 */
 	for (i = 0 ; i < ICU_MAX_IRQS ; i++) {
-		icu_int = readl(icu->base + ICU_INT_CFG(i));
+		u32 icu_int = readl_relaxed(icu->base + ICU_INT_CFG(i));
 		if ((icu_int >> ICU_GROUP_SHIFT) == ICU_GRP_NSR)
 			writel_relaxed(0x0, icu->base + ICU_INT_CFG(i));
 	}
-- 
2.14.2

[PATCH v2 4/9] dma-iommu: Fix compilation when !CONFIG_IOMMU_DMA

[Marc Zyngier]

Inclusion of include/dma-iommu.h when CONFIG_IOMMU_DMA is not selected
results in the following splat:

In file included from drivers/irqchip/irq-gic-v3-mbi.c:20:0:
./include/linux/dma-iommu.h:95:69: error: unknown type name ‘dma_addr_t’
 static inline int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
                                                                     ^~~~~~~~~~
./include/linux/dma-iommu.h:108:74: warning: ‘struct list_head’ declared inside parameter list will not be visible outside of this definition or declaration
 static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
                                                                          ^~~~~~~~~
scripts/Makefile.build:312: recipe for target 'drivers/irqchip/irq-gic-v3-mbi.o' failed

Fix it by including linux/types.h.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 include/linux/dma-iommu.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 92f20832fd28..e8ca5e654277 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -17,6 +17,7 @@
 #define __DMA_IOMMU_H
 
 #ifdef __KERNEL__
+#include <linux/types.h>
 #include <asm/errno.h>
 
 #ifdef CONFIG_IOMMU_DMA
-- 
2.14.2

[PATCH v2 5/9] irqdomain: Let irq_find_host default to DOMAIN_BUS_WIRED

[Marc Zyngier]

At the beginning of times, irq_find_host() was simple. Each device node
implemented at most one irq domain, and we were happy. Over time, things
have become more complex, and we now have nodes implementing a plurality
of domains, tagged by "bus_token".

Crutially, users of irq_find_host() all expect the most basic domain
to be returned, and not any other domain such as a bus-specific MSI
domain.

So let's change irq_find_host() to first look for a DOMAIN_BUS_WIRED
domain, and only if this fails fallback to DOMAIN_BUS_ANY. Note that
this is consistent with what irq_create_fwspec_mapping is already
doing, see 530cbe100ef7 ("irqdomain: Allow domain lookup with
DOMAIN_BUS_WIRED token").

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 include/linux/irqdomain.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 48c7e86bb556..dccfa65aee96 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -301,7 +301,13 @@ static inline struct irq_domain *irq_find_matching_host(struct device_node *node
 
 static inline struct irq_domain *irq_find_host(struct device_node *node)
 {
-	return irq_find_matching_host(node, DOMAIN_BUS_ANY);
+	struct irq_domain *d;
+
+	d = irq_find_matching_host(node, DOMAIN_BUS_WIRED);
+	if (!d)
+		d = irq_find_matching_host(node, DOMAIN_BUS_ANY);
+
+	return d;
 }
 
 /**
-- 
2.14.2

[PATCH v2 6/9] irqchip/gic-v3: Mark the base irq domain as DOMAIN_BUS_WIRED

[Marc Zyngier]

As we're about to introduce MSI domains based on top of the GICv3
domain, we must make sure nothing the new domains do not alias
with the core domain.

So let's tag that core domain with the DOMAIN_BUS_WIRED attribute,
ensuring it gets picked up by other drivers that use irq_find_host().

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-gic-v3.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index e5d101418390..94164d7b87a6 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1099,6 +1099,7 @@ static int __init gic_init_bases(void __iomem *dist_base,
 
 	gic_data.domain = irq_domain_create_tree(handle, &gic_irq_domain_ops,
 						 &gic_data);
+	irq_domain_update_bus_token(gic_data.domain, DOMAIN_BUS_WIRED);
 	gic_data.rdists.rdist = alloc_percpu(typeof(*gic_data.rdists.rdist));
 	gic_data.rdists.has_vlpis = true;
 	gic_data.rdists.has_direct_lpi = true;
-- 
2.14.2

[PATCH v2 7/9] irqchip/gic-v3: Add support for Message Based Interrupts as an MSI controller

[Marc Zyngier]

GICv3 offers the possibility to signal SPIs using a pair of doorbells
(SETPI, CLRSPI) under the name of Message Based Interrupts (MBI).
They can be used as either traditional (edge) MSIs, or the more exotic
level-triggered flavour.

Let's implement support for platform MSI, which is the original intent
for this feature.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/Makefile           |   2 +-
 drivers/irqchip/irq-gic-v3-mbi.c   | 275 +++++++++++++++++++++++++++++++++++++
 drivers/irqchip/irq-gic-v3.c       |   6 +
 include/linux/irqchip/arm-gic-v3.h |   1 +
 4 files changed, 283 insertions(+), 1 deletion(-)
 create mode 100644 drivers/irqchip/irq-gic-v3-mbi.c

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 5ed465ab1c76..15f268f646bf 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -27,7 +27,7 @@ obj-$(CONFIG_ARM_GIC)			+= irq-gic.o irq-gic-common.o
 obj-$(CONFIG_ARM_GIC_PM)		+= irq-gic-pm.o
 obj-$(CONFIG_ARCH_REALVIEW)		+= irq-gic-realview.o
 obj-$(CONFIG_ARM_GIC_V2M)		+= irq-gic-v2m.o
-obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-common.o
+obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-v3-mbi.o irq-gic-common.o
 obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-platform-msi.o irq-gic-v4.o
 obj-$(CONFIG_ARM_GIC_V3_ITS_PCI)	+= irq-gic-v3-its-pci-msi.o
 obj-$(CONFIG_ARM_GIC_V3_ITS_FSL_MC)	+= irq-gic-v3-its-fsl-mc-msi.o
diff --git a/drivers/irqchip/irq-gic-v3-mbi.c b/drivers/irqchip/irq-gic-v3-mbi.c
new file mode 100644
index 000000000000..2b3b767050aa
--- /dev/null
+++ b/drivers/irqchip/irq-gic-v3-mbi.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 ARM Limited, All Rights Reserved.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#define pr_fmt(fmt) "GICv3: " fmt
+
+#include <linux/dma-iommu.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <linux/irqchip/arm-gic-v3.h>
+
+struct mbi_range {
+	u32			spi_start;
+	u32			nr_spis;
+	unsigned long		*bm;
+};
+
+static struct mutex		mbi_lock;
+static phys_addr_t		mbi_phys_base;
+static struct mbi_range		*mbi_ranges;
+static unsigned int		mbi_range_nr;
+
+static struct irq_chip mbi_irq_chip = {
+	.name			= "MBI",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+};
+
+static int mbi_irq_gic_domain_alloc(struct irq_domain *domain,
+				       unsigned int virq,
+				       irq_hw_number_t hwirq)
+{
+	struct irq_fwspec fwspec;
+	struct irq_data *d;
+	int err;
+
+	/*
+	 * Using ACPI? There is no MBI support in the spec, you
+	 * shouldn't even be here.
+	 */
+	if (!is_of_node(domain->parent->fwnode))
+		return -EINVAL;
+
+	/*
+	 * Let's default to edge. This is consistent with traditional
+	 * MSIs, and systems requiring level signaling will just
+	 * enforce the trigger on their own.
+	 */
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	fwspec.param[0] = 0;
+	fwspec.param[1] = hwirq - 32;
+	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+
+	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (err)
+		return err;
+
+	d = irq_domain_get_irq_data(domain->parent, virq);
+	return d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
+}
+
+static void mbi_free_msi(struct mbi_range *mbi, unsigned int hwirq,
+			 int nr_irqs)
+{
+	mutex_lock(&mbi_lock);
+	bitmap_release_region(mbi->bm, hwirq - mbi->spi_start,
+			      get_count_order(nr_irqs));
+	mutex_unlock(&mbi_lock);
+}
+
+static int mbi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				   unsigned int nr_irqs, void *args)
+{
+	struct mbi_range *mbi = NULL;
+	int hwirq, offset, i, err = 0;
+
+	mutex_lock(&mbi_lock);
+	for (i = 0; i < mbi_range_nr; i++) {
+		offset = bitmap_find_free_region(mbi_ranges[i].bm,
+						 mbi_ranges[i].nr_spis,
+						 get_count_order(nr_irqs));
+		if (offset >= 0) {
+			mbi = &mbi_ranges[i];
+			break;
+		}
+	}
+	mutex_unlock(&mbi_lock);
+
+	if (!mbi)
+		return -ENOSPC;
+
+	hwirq = mbi->spi_start + offset;
+
+	for (i = 0; i < nr_irqs; i++) {
+		err = mbi_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
+		if (err)
+			goto fail;
+
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+					      &mbi_irq_chip, mbi);
+	}
+
+	return 0;
+
+fail:
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+	mbi_free_msi(mbi, hwirq, nr_irqs);
+	return err;
+}
+
+static void mbi_irq_domain_free(struct irq_domain *domain,
+				unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	struct mbi_range *mbi = irq_data_get_irq_chip_data(d);
+
+	mbi_free_msi(mbi, d->hwirq, nr_irqs);
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops mbi_domain_ops = {
+	.alloc			= mbi_irq_domain_alloc,
+	.free			= mbi_irq_domain_free,
+};
+
+static void mbi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	msg[0].address_hi = upper_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
+	msg[0].address_lo = lower_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
+	msg[0].data = data->parent_data->hwirq;
+
+	iommu_dma_map_msi_msg(data->irq, msg);
+}
+
+static void mbi_compose_mbi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	mbi_compose_msi_msg(data, msg);
+
+	msg[1].address_hi = upper_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
+	msg[1].address_lo = lower_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
+	msg[1].data = data->parent_data->hwirq;
+
+	iommu_dma_map_msi_msg(data->irq, &msg[1]);
+}
+
+/* Platform-MSI specific irqchip */
+static struct irq_chip mbi_pmsi_irq_chip = {
+	.name			= "pMSI",
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_compose_msi_msg	= mbi_compose_mbi_msg,
+	.flags			= IRQCHIP_SUPPORTS_LEVEL_MSI,
+};
+
+static struct msi_domain_ops mbi_pmsi_ops = {
+};
+
+static struct msi_domain_info mbi_pmsi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_LEVEL_CAPABLE),
+	.ops	= &mbi_pmsi_ops,
+	.chip	= &mbi_pmsi_irq_chip,
+};
+
+static int mbi_allocate_domains(struct irq_domain *parent)
+{
+	struct irq_domain *nexus_domain, *plat_domain;
+
+	nexus_domain = irq_domain_create_tree(parent->fwnode,
+					      &mbi_domain_ops, NULL);
+	if (!nexus_domain)
+		return -ENOMEM;
+
+	irq_domain_update_bus_token(nexus_domain, DOMAIN_BUS_NEXUS);
+	nexus_domain->parent = parent;
+
+	plat_domain = platform_msi_create_irq_domain(parent->fwnode,
+						     &mbi_pmsi_domain_info,
+						     nexus_domain);
+
+	if (!plat_domain) {
+		irq_domain_remove(plat_domain);
+		irq_domain_remove(nexus_domain);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int __init mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent)
+{
+	struct device_node *np;
+	const __be32 *reg;
+	int ret, n;
+
+	np = to_of_node(fwnode);
+
+	if (!of_property_read_bool(np, "msi-controller"))
+		return 0;
+
+	n = of_property_count_elems_of_size(np, "mbi-ranges", sizeof(u32));
+	if (n <= 0 || n % 2)
+		return -EINVAL;
+
+	mbi_range_nr = n / 2;
+	mbi_ranges = kcalloc(mbi_range_nr, sizeof(*mbi_ranges), GFP_KERNEL);
+	if (!mbi_ranges)
+		return -ENOMEM;
+
+	for (n = 0; n < mbi_range_nr; n++) {
+		ret = of_property_read_u32_index(np, "mbi-ranges", n * 2,
+						 &mbi_ranges[n].spi_start);
+		if (ret)
+			goto err_free_mbi;
+		ret = of_property_read_u32_index(np, "mbi-ranges", n * 2 + 1,
+						 &mbi_ranges[n].nr_spis);
+		if (ret)
+			goto err_free_mbi;
+
+		mbi_ranges[n].bm = kcalloc(BITS_TO_LONGS(mbi_ranges[n].nr_spis),
+					   sizeof(long), GFP_KERNEL);
+		if (!mbi_ranges[n].bm) {
+			ret = -ENOMEM;
+			goto err_free_mbi;
+		}
+		pr_info("MBI range [%d:%d]\n", mbi_ranges[n].spi_start,
+			mbi_ranges[n].spi_start + mbi_ranges[n].nr_spis - 1);
+	}
+
+	reg = of_get_property(np, "mbi-alias", NULL);
+	if (reg) {
+		mbi_phys_base = of_translate_address(np, reg);
+		if (mbi_phys_base == OF_BAD_ADDR) {
+			ret = -ENXIO;
+			goto err_free_mbi;
+		}
+	} else {
+		struct resource res;
+
+		if (of_address_to_resource(np, 0, &res)) {
+			ret = -ENXIO;
+			goto err_free_mbi;
+		}
+
+		mbi_phys_base = res.start;
+	}
+
+	pr_info("Using MBI frame %pa\n", &mbi_phys_base);
+
+	ret = mbi_allocate_domains(parent);
+	if (ret)
+		goto err_free_mbi;
+
+	return 0;
+
+err_free_mbi:
+	if (mbi_ranges) {
+		for (n = 0; n < mbi_range_nr; n++)
+			kfree(mbi_ranges[n].bm);
+		kfree(mbi_ranges);
+	}
+
+	return ret;
+}
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 94164d7b87a6..5a67ec084588 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1113,6 +1113,12 @@ static int __init gic_init_bases(void __iomem *dist_base,
 	pr_info("Distributor has %sRange Selector support\n",
 		gic_data.has_rss ? "" : "no ");
 
+	if (typer & GICD_TYPER_MBIS) {
+		err = mbi_init(handle, gic_data.domain);
+		if (err)
+			pr_err("Failed to initialize MBIs\n");
+	}
+
 	set_handle_irq(gic_handle_irq);
 
 	gic_update_vlpi_properties();
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index f5af3b594e6e..cbb872c1b607 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -587,6 +587,7 @@ struct fwnode_handle;
 int its_cpu_init(void);
 int its_init(struct fwnode_handle *handle, struct rdists *rdists,
 	     struct irq_domain *domain);
+int mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent);
 
 static inline bool gic_enable_sre(void)
 {
-- 
2.14.2

[PATCH v2 8/9] irqchip/gic-v3: Add PCI/MSI support to the GICv3 MBI sub-driver

[Marc Zyngier]

You would hope that if you have a GICv3 in your system, you'd use the ITS,
as it provides a large interrupt ID space and device isolation. Sadly,
some SoC integrations are less than perfect, and the ITS is not usesable on
those.

The only solution for these systems is to use the MBI interface, and
rely on a very small number of possible vectors.

This patch thus adds minimal support for PCI/MSI on top of the GICv3
MBI driver. Please don't use it if you can avoid it.

Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-gic-v3-mbi.c | 62 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 59 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-mbi.c b/drivers/irqchip/irq-gic-v3-mbi.c
index 2b3b767050aa..ad70e7c416e3 100644
--- a/drivers/irqchip/irq-gic-v3-mbi.c
+++ b/drivers/irqchip/irq-gic-v3-mbi.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/msi.h>
 #include <linux/of_address.h>
+#include <linux/of_pci.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
@@ -144,6 +145,55 @@ static void mbi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 	iommu_dma_map_msi_msg(data->irq, msg);
 }
 
+#ifdef CONFIG_PCI_MSI
+/* PCI-specific irqchip */
+static void mbi_mask_msi_irq(struct irq_data *d)
+{
+	pci_msi_mask_irq(d);
+	irq_chip_mask_parent(d);
+}
+
+static void mbi_unmask_msi_irq(struct irq_data *d)
+{
+	pci_msi_unmask_irq(d);
+	irq_chip_unmask_parent(d);
+}
+
+static struct irq_chip mbi_msi_irq_chip = {
+	.name			= "MSI",
+	.irq_mask		= mbi_mask_msi_irq,
+	.irq_unmask		= mbi_unmask_msi_irq,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_compose_msi_msg	= mbi_compose_msi_msg,
+	.irq_write_msi_msg	= pci_msi_domain_write_msg,
+};
+
+static struct msi_domain_info mbi_msi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
+	.chip	= &mbi_msi_irq_chip,
+};
+
+static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
+				   struct irq_domain **pci_domain)
+{
+	*pci_domain = pci_msi_create_irq_domain(nexus_domain->parent->fwnode,
+						&mbi_msi_domain_info,
+						nexus_domain);
+	if (!*pci_domain)
+		return -ENOMEM;
+
+	return 0;
+}
+#else
+static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
+				   struct irq_domain **pci_domain)
+{
+	*pci_domain = NULL;
+	return 0;
+}
+#endif
+
 static void mbi_compose_mbi_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	mbi_compose_msi_msg(data, msg);
@@ -175,7 +225,8 @@ static struct msi_domain_info mbi_pmsi_domain_info = {
 
 static int mbi_allocate_domains(struct irq_domain *parent)
 {
-	struct irq_domain *nexus_domain, *plat_domain;
+	struct irq_domain *nexus_domain, *pci_domain, *plat_domain;
+	int err;
 
 	nexus_domain = irq_domain_create_tree(parent->fwnode,
 					      &mbi_domain_ops, NULL);
@@ -185,12 +236,17 @@ static int mbi_allocate_domains(struct irq_domain *parent)
 	irq_domain_update_bus_token(nexus_domain, DOMAIN_BUS_NEXUS);
 	nexus_domain->parent = parent;
 
+	err = mbi_allocate_pci_domain(nexus_domain, &pci_domain);
+
 	plat_domain = platform_msi_create_irq_domain(parent->fwnode,
 						     &mbi_pmsi_domain_info,
 						     nexus_domain);
 
-	if (!plat_domain) {
-		irq_domain_remove(plat_domain);
+	if (err || !plat_domain) {
+		if (plat_domain)
+			irq_domain_remove(plat_domain);
+		if (pci_domain)
+			irq_domain_remove(pci_domain);
 		irq_domain_remove(nexus_domain);
 		return -ENOMEM;
 	}
-- 
2.14.2

[PATCH v2 9/9] dt-bindings/gic-v3: Add documentation for MBI support

[Marc Zyngier]

Add the required properties to support the MBI feature on GICv3.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 .../bindings/interrupt-controller/arm,gic-v3.txt        | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
index 0a57f2f4167d..3ea78c4ef887 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
+++ b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
@@ -57,6 +57,20 @@ Optional
   occupied by the redistributors. Required if more than one such
   region is present.
 
+- msi-controller: Boolean property. Identifies the node as an MSI
+  controller. Only present if the Message Based Interrupt
+  functionnality is being exposed by the HW, and the mbi-ranges
+  property present.
+
+- mbi-ranges: A list of pairs <intid span>, where "intid" is the first
+  SPI of a range that can be used an MBI, and "span" the size of that
+  range. Multiple ranges can be provided. Requires "msi-controller" to
+  be set.
+
+- mbi-alias: Address property. Base address of an alias of the GICD
+  region containing only the {SET,CLR}SPI registers to be used if
+  isolation is required, and if supported by the HW.
+
 Sub-nodes:
 
 PPI affinity can be expressed as a single "ppi-partitions" node,
@@ -99,6 +113,9 @@ Examples:
 		      <0x0 0x2c020000 0 0x2000>;	// GICV
 		interrupts = <1 9 4>;
 
+		msi-controller;
+		mbi-ranges = <256 128>;
+
 		gic-its@2c200000 {
 			compatible = "arm,gic-v3-its";
 			msi-controller;
-- 
2.14.2

[tip:irq/core] genirq/msi: Allow level-triggered MSIs to be exposed by MSI providers

[tip-bot for Marc Zyngier]

Commit-ID:  0be8153cbc2af9a96e9ab8631fc3ba23bb52dbe3
Gitweb:     https://git.kernel.org/tip/0be8153cbc2af9a96e9ab8631fc3ba23bb52dbe3
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:30 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:58:59 +0200

genirq/msi: Allow level-triggered MSIs to be exposed by MSI providers

So far, MSIs have been used to signal edge-triggered interrupts, as
a write is a good model for an edge (you can't "unwrite" something).
On the other hand, routing zillions of wires in an SoC because you
need level interrupts is a bit extreme.

People have come up with a variety of schemes to support this, which
involves sending two messages: one to signal the interrupt, and one
to clear it. Since the kernel cannot represent this, we've ended up
with side-band mechanisms that are pretty awful.

Instead, let's acknoledge the requirement, and ensure that, under the
right circumstances, the irq_compose_msg and irq_write_msg can take
as a parameter an array of two messages instead of a pointer to a
single one. We also add some checking that the compose method only
clobbers the second message if the MSI domain has been created with
the MSI_FLAG_LEVEL_CAPABLE flags.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-2-marc.zyngier@arm.com

---
 include/linux/msi.h |  2 ++
 kernel/irq/msi.c    | 33 ++++++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 1f1bbb5b4679..5839d8062dfc 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -289,6 +289,8 @@ enum {
 	 * MSI_FLAG_ACTIVATE_EARLY has been set.
 	 */
 	MSI_FLAG_MUST_REACTIVATE	= (1 << 5),
+	/* Is level-triggered capable, using two messages */
+	MSI_FLAG_LEVEL_CAPABLE		= (1 << 6),
 };
 
 int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 2a8571f72b17..4ca2fd46645d 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -76,6 +76,19 @@ static inline void irq_chip_write_msi_msg(struct irq_data *data,
 	data->chip->irq_write_msi_msg(data, msg);
 }
 
+static void msi_check_level(struct irq_domain *domain, struct msi_msg *msg)
+{
+	struct msi_domain_info *info = domain->host_data;
+
+	/*
+	 * If the MSI provider has messed with the second message and
+	 * not advertized that it is level-capable, signal the breakage.
+	 */
+	WARN_ON(!((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
+		  (info->chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)) &&
+		(msg[1].address_lo || msg[1].address_hi || msg[1].data));
+}
+
 /**
  * msi_domain_set_affinity - Generic affinity setter function for MSI domains
  * @irq_data:	The irq data associated to the interrupt
@@ -89,13 +102,14 @@ int msi_domain_set_affinity(struct irq_data *irq_data,
 			    const struct cpumask *mask, bool force)
 {
 	struct irq_data *parent = irq_data->parent_data;
-	struct msi_msg msg;
+	struct msi_msg msg[2] = { [1] = { }, };
 	int ret;
 
 	ret = parent->chip->irq_set_affinity(parent, mask, force);
 	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
-		BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
-		irq_chip_write_msi_msg(irq_data, &msg);
+		BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
+		msi_check_level(irq_data->domain, msg);
+		irq_chip_write_msi_msg(irq_data, msg);
 	}
 
 	return ret;
@@ -104,20 +118,21 @@ int msi_domain_set_affinity(struct irq_data *irq_data,
 static int msi_domain_activate(struct irq_domain *domain,
 			       struct irq_data *irq_data, bool early)
 {
-	struct msi_msg msg;
+	struct msi_msg msg[2] = { [1] = { }, };
 
-	BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
-	irq_chip_write_msi_msg(irq_data, &msg);
+	BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
+	msi_check_level(irq_data->domain, msg);
+	irq_chip_write_msi_msg(irq_data, msg);
 	return 0;
 }
 
 static void msi_domain_deactivate(struct irq_domain *domain,
 				  struct irq_data *irq_data)
 {
-	struct msi_msg msg;
+	struct msi_msg msg[2];
 
-	memset(&msg, 0, sizeof(msg));
-	irq_chip_write_msi_msg(irq_data, &msg);
+	memset(msg, 0, sizeof(msg));
+	irq_chip_write_msi_msg(irq_data, msg);
 }
 
 static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,

[tip:irq/core] genirq/msi: Limit level-triggered MSI to platform devices

[tip-bot for Marc Zyngier]

Commit-ID:  6988e0e0d28328467e218f59589b2770675a9ebd
Gitweb:     https://git.kernel.org/tip/6988e0e0d28328467e218f59589b2770675a9ebd
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:31 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:58:59 +0200

genirq/msi: Limit level-triggered MSI to platform devices

Nobody would be insane enough to try and use level triggered
MSIs on PCI, but let's make sure it doesn't happen. Also,
let's mandate that the irqchip backing the platform MSI domain
is providing the IRQCHIP_SUPPORTS_LEVEL_MSI flag.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-3-marc.zyngier@arm.com

---
 drivers/base/platform-msi.c     | 3 +++
 drivers/bus/fsl-mc/fsl-mc-msi.c | 2 ++
 drivers/pci/msi.c               | 3 +++
 include/linux/irq.h             | 1 +
 4 files changed, 9 insertions(+)

diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c
index 8e22073aeeed..60d6cc618f1c 100644
--- a/drivers/base/platform-msi.c
+++ b/drivers/base/platform-msi.c
@@ -101,6 +101,9 @@ static void platform_msi_update_chip_ops(struct msi_domain_info *info)
 		chip->irq_set_affinity = msi_domain_set_affinity;
 	if (!chip->irq_write_msi_msg)
 		chip->irq_write_msi_msg = platform_msi_write_msg;
+	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
+		    !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
 }
 
 static void platform_msi_free_descs(struct device *dev, int base, int nvec)
diff --git a/drivers/bus/fsl-mc/fsl-mc-msi.c b/drivers/bus/fsl-mc/fsl-mc-msi.c
index ec35e255b496..8b9c66d7c4ff 100644
--- a/drivers/bus/fsl-mc/fsl-mc-msi.c
+++ b/drivers/bus/fsl-mc/fsl-mc-msi.c
@@ -163,6 +163,8 @@ struct irq_domain *fsl_mc_msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
+	if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE)))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		fsl_mc_msi_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 30250631efe7..f45b74fcc059 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1434,6 +1434,9 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
+	if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
+
 	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 		pci_msi_domain_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 65916a305f3d..b2067083aa94 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -512,6 +512,7 @@ enum {
 	IRQCHIP_SKIP_SET_WAKE		= (1 <<  4),
 	IRQCHIP_ONESHOT_SAFE		= (1 <<  5),
 	IRQCHIP_EOI_THREADED		= (1 <<  6),
+	IRQCHIP_SUPPORTS_LEVEL_MSI	= (1 <<  7),
 };
 
 #include <linux/irqdesc.h>

[tip:irq/core] irqchip/mvebu-gicp: Use level-triggered MSIs between ICU and GICP

[tip-bot for Marc Zyngier]

Commit-ID:  25eaaabb51c9925dc65f5b54fd9a362bf118e70a
Gitweb:     https://git.kernel.org/tip/25eaaabb51c9925dc65f5b54fd9a362bf118e70a
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:32 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:59:00 +0200

irqchip/mvebu-gicp: Use level-triggered MSIs between ICU and GICP

The ICU and GICP drivers are using an ugly side-band mechanism to
find out about the "clear" doorbell when using level interrupts.

Let's convert it to level-triggered MSIs, which result in a nice
cleanup.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-4-marc.zyngier@arm.com

---
 drivers/irqchip/irq-mvebu-gicp.c | 38 +++++++++++---------------------------
 drivers/irqchip/irq-mvebu-gicp.h | 12 ------------
 drivers/irqchip/irq-mvebu-icu.c  | 33 +++++++++++++++++----------------
 3 files changed, 28 insertions(+), 55 deletions(-)

diff --git a/drivers/irqchip/irq-mvebu-gicp.c b/drivers/irqchip/irq-mvebu-gicp.c
index 17a4a7b6cdbb..4e17f7081efc 100644
--- a/drivers/irqchip/irq-mvebu-gicp.c
+++ b/drivers/irqchip/irq-mvebu-gicp.c
@@ -19,8 +19,6 @@
 
 #include <dt-bindings/interrupt-controller/arm-gic.h>
 
-#include "irq-mvebu-gicp.h"
-
 #define GICP_SETSPI_NSR_OFFSET	0x0
 #define GICP_CLRSPI_NSR_OFFSET	0x8
 
@@ -55,34 +53,18 @@ static int gicp_idx_to_spi(struct mvebu_gicp *gicp, int idx)
 	return -EINVAL;
 }
 
-int mvebu_gicp_get_doorbells(struct device_node *dn, phys_addr_t *setspi,
-			     phys_addr_t *clrspi)
-{
-	struct platform_device *pdev;
-	struct mvebu_gicp *gicp;
-
-	pdev = of_find_device_by_node(dn);
-	if (!pdev)
-		return -ENODEV;
-
-	gicp = platform_get_drvdata(pdev);
-	if (!gicp)
-		return -ENODEV;
-
-	*setspi = gicp->res->start + GICP_SETSPI_NSR_OFFSET;
-	*clrspi = gicp->res->start + GICP_CLRSPI_NSR_OFFSET;
-
-	return 0;
-}
-
 static void gicp_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	struct mvebu_gicp *gicp = data->chip_data;
 	phys_addr_t setspi = gicp->res->start + GICP_SETSPI_NSR_OFFSET;
-
-	msg->data = data->hwirq;
-	msg->address_lo = lower_32_bits(setspi);
-	msg->address_hi = upper_32_bits(setspi);
+	phys_addr_t clrspi = gicp->res->start + GICP_CLRSPI_NSR_OFFSET;
+
+	msg[0].data = data->hwirq;
+	msg[0].address_lo = lower_32_bits(setspi);
+	msg[0].address_hi = upper_32_bits(setspi);
+	msg[1].data = data->hwirq;
+	msg[1].address_lo = lower_32_bits(clrspi);
+	msg[1].address_hi = upper_32_bits(clrspi);
 }
 
 static struct irq_chip gicp_irq_chip = {
@@ -170,13 +152,15 @@ static const struct irq_domain_ops gicp_domain_ops = {
 static struct irq_chip gicp_msi_irq_chip = {
 	.name		= "GICP",
 	.irq_set_type	= irq_chip_set_type_parent,
+	.flags		= IRQCHIP_SUPPORTS_LEVEL_MSI,
 };
 
 static struct msi_domain_ops gicp_msi_ops = {
 };
 
 static struct msi_domain_info gicp_msi_domain_info = {
-	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_LEVEL_CAPABLE),
 	.ops	= &gicp_msi_ops,
 	.chip	= &gicp_msi_irq_chip,
 };
diff --git a/drivers/irqchip/irq-mvebu-gicp.h b/drivers/irqchip/irq-mvebu-gicp.h
deleted file mode 100644
index eaa12fb72102..000000000000
--- a/drivers/irqchip/irq-mvebu-gicp.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __MVEBU_GICP_H__
-#define __MVEBU_GICP_H__
-
-#include <linux/types.h>
-
-struct device_node;
-
-int mvebu_gicp_get_doorbells(struct device_node *dn, phys_addr_t *setspi,
-			     phys_addr_t *clrspi);
-
-#endif /* __MVEBU_GICP_H__ */
diff --git a/drivers/irqchip/irq-mvebu-icu.c b/drivers/irqchip/irq-mvebu-icu.c
index e18c48d3a92e..13063339b416 100644
--- a/drivers/irqchip/irq-mvebu-icu.c
+++ b/drivers/irqchip/irq-mvebu-icu.c
@@ -21,8 +21,6 @@
 
 #include <dt-bindings/interrupt-controller/mvebu-icu.h>
 
-#include "irq-mvebu-gicp.h"
-
 /* ICU registers */
 #define ICU_SETSPI_NSR_AL	0x10
 #define ICU_SETSPI_NSR_AH	0x14
@@ -43,6 +41,7 @@ struct mvebu_icu {
 	void __iomem *base;
 	struct irq_domain *domain;
 	struct device *dev;
+	atomic_t initialized;
 };
 
 struct mvebu_icu_irq_data {
@@ -51,6 +50,18 @@ struct mvebu_icu_irq_data {
 	unsigned int type;
 };
 
+static void mvebu_icu_init(struct mvebu_icu *icu, struct msi_msg *msg)
+{
+	if (atomic_cmpxchg(&icu->initialized, false, true))
+		return;
+
+	/* Set Clear/Set ICU SPI message address in AP */
+	writel_relaxed(msg[0].address_hi, icu->base + ICU_SETSPI_NSR_AH);
+	writel_relaxed(msg[0].address_lo, icu->base + ICU_SETSPI_NSR_AL);
+	writel_relaxed(msg[1].address_hi, icu->base + ICU_CLRSPI_NSR_AH);
+	writel_relaxed(msg[1].address_lo, icu->base + ICU_CLRSPI_NSR_AL);
+}
+
 static void mvebu_icu_write_msg(struct msi_desc *desc, struct msi_msg *msg)
 {
 	struct irq_data *d = irq_get_irq_data(desc->irq);
@@ -59,6 +70,8 @@ static void mvebu_icu_write_msg(struct msi_desc *desc, struct msi_msg *msg)
 	unsigned int icu_int;
 
 	if (msg->address_lo || msg->address_hi) {
+		/* One off initialization */
+		mvebu_icu_init(icu, msg);
 		/* Configure the ICU with irq number & type */
 		icu_int = msg->data | ICU_INT_ENABLE;
 		if (icu_irqd->type & IRQ_TYPE_EDGE_RISING)
@@ -197,9 +210,7 @@ static int mvebu_icu_probe(struct platform_device *pdev)
 	struct device_node *node = pdev->dev.of_node;
 	struct device_node *gicp_dn;
 	struct resource *res;
-	phys_addr_t setspi, clrspi;
-	u32 i, icu_int;
-	int ret;
+	int i;
 
 	icu = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_icu),
 			   GFP_KERNEL);
@@ -242,22 +253,12 @@ static int mvebu_icu_probe(struct platform_device *pdev)
 	if (!gicp_dn)
 		return -ENODEV;
 
-	ret = mvebu_gicp_get_doorbells(gicp_dn, &setspi, &clrspi);
-	if (ret)
-		return ret;
-
-	/* Set Clear/Set ICU SPI message address in AP */
-	writel_relaxed(upper_32_bits(setspi), icu->base + ICU_SETSPI_NSR_AH);
-	writel_relaxed(lower_32_bits(setspi), icu->base + ICU_SETSPI_NSR_AL);
-	writel_relaxed(upper_32_bits(clrspi), icu->base + ICU_CLRSPI_NSR_AH);
-	writel_relaxed(lower_32_bits(clrspi), icu->base + ICU_CLRSPI_NSR_AL);
-
 	/*
 	 * Clean all ICU interrupts with type SPI_NSR, required to
 	 * avoid unpredictable SPI assignments done by firmware.
 	 */
 	for (i = 0 ; i < ICU_MAX_IRQS ; i++) {
-		icu_int = readl(icu->base + ICU_INT_CFG(i));
+		u32 icu_int = readl_relaxed(icu->base + ICU_INT_CFG(i));
 		if ((icu_int >> ICU_GROUP_SHIFT) == ICU_GRP_NSR)
 			writel_relaxed(0x0, icu->base + ICU_INT_CFG(i));
 	}

[tip:irq/core] dma-iommu: Fix compilation when !CONFIG_IOMMU_DMA

[tip-bot for Marc Zyngier]

Commit-ID:  8a22a3e1e768c309b718f99bd86f9f25a453e0dc
Gitweb:     https://git.kernel.org/tip/8a22a3e1e768c309b718f99bd86f9f25a453e0dc
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:33 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:59:00 +0200

dma-iommu: Fix compilation when !CONFIG_IOMMU_DMA

Inclusion of include/dma-iommu.h when CONFIG_IOMMU_DMA is not selected
results in the following splat:

In file included from drivers/irqchip/irq-gic-v3-mbi.c:20:0:
./include/linux/dma-iommu.h:95:69: error: unknown type name ‘dma_addr_t’
 static inline int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
                                                                     ^~~~~~~~~~
./include/linux/dma-iommu.h:108:74: warning: ‘struct list_head’ declared inside parameter list will not be visible outside of this definition or declaration
 static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
                                                                          ^~~~~~~~~
scripts/Makefile.build:312: recipe for target 'drivers/irqchip/irq-gic-v3-mbi.o' failed

Fix it by including linux/types.h.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-5-marc.zyngier@arm.com

---
 include/linux/dma-iommu.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 92f20832fd28..e8ca5e654277 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -17,6 +17,7 @@
 #define __DMA_IOMMU_H
 
 #ifdef __KERNEL__
+#include <linux/types.h>
 #include <asm/errno.h>
 
 #ifdef CONFIG_IOMMU_DMA

[tip:irq/core] irqdomain: Let irq_find_host default to DOMAIN_BUS_WIRED

[tip-bot for Marc Zyngier]

Commit-ID:  6461934371bfc1bfe6b424b197a546b4effd0a32
Gitweb:     https://git.kernel.org/tip/6461934371bfc1bfe6b424b197a546b4effd0a32
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:34 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:59:00 +0200

irqdomain: Let irq_find_host default to DOMAIN_BUS_WIRED

At the beginning of times, irq_find_host() was simple. Each device node
implemented at most one irq domain, and we were happy. Over time, things
have become more complex, and we now have nodes implementing a plurality
of domains, tagged by "bus_token".

Crutially, users of irq_find_host() all expect the most basic domain
to be returned, and not any other domain such as a bus-specific MSI
domain.

So let's change irq_find_host() to first look for a DOMAIN_BUS_WIRED
domain, and only if this fails fallback to DOMAIN_BUS_ANY. Note that
this is consistent with what irq_create_fwspec_mapping is already
doing, see 530cbe100ef7 ("irqdomain: Allow domain lookup with
DOMAIN_BUS_WIRED token").

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-6-marc.zyngier@arm.com

---
 include/linux/irqdomain.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 48c7e86bb556..dccfa65aee96 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -301,7 +301,13 @@ static inline struct irq_domain *irq_find_matching_host(struct device_node *node
 
 static inline struct irq_domain *irq_find_host(struct device_node *node)
 {
-	return irq_find_matching_host(node, DOMAIN_BUS_ANY);
+	struct irq_domain *d;
+
+	d = irq_find_matching_host(node, DOMAIN_BUS_WIRED);
+	if (!d)
+		d = irq_find_matching_host(node, DOMAIN_BUS_ANY);
+
+	return d;
 }
 
 /**

[tip:irq/core] irqchip/gic-v3: Mark the base irq domain as DOMAIN_BUS_WIRED

[tip-bot for Marc Zyngier]

Commit-ID:  b2425b51bed7437c08c11ce71bb0f308f4516451
Gitweb:     https://git.kernel.org/tip/b2425b51bed7437c08c11ce71bb0f308f4516451
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:35 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:59:01 +0200

irqchip/gic-v3: Mark the base irq domain as DOMAIN_BUS_WIRED

As we're about to introduce MSI domains based on top of the GICv3
domain, we must make sure nothing the new domains do not alias
with the core domain.

So let's tag that core domain with the DOMAIN_BUS_WIRED attribute,
ensuring it gets picked up by other drivers that use irq_find_host().

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-7-marc.zyngier@arm.com

---
 drivers/irqchip/irq-gic-v3.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index e5d101418390..94164d7b87a6 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1099,6 +1099,7 @@ static int __init gic_init_bases(void __iomem *dist_base,
 
 	gic_data.domain = irq_domain_create_tree(handle, &gic_irq_domain_ops,
 						 &gic_data);
+	irq_domain_update_bus_token(gic_data.domain, DOMAIN_BUS_WIRED);
 	gic_data.rdists.rdist = alloc_percpu(typeof(*gic_data.rdists.rdist));
 	gic_data.rdists.has_vlpis = true;
 	gic_data.rdists.has_direct_lpi = true;

[tip:irq/core] irqchip/gic-v3: Add support for Message Based Interrupts as an MSI controller

[tip-bot for Marc Zyngier]

Commit-ID:  505287525c24d5c78b662fd73721ad9900b91fcc
Gitweb:     https://git.kernel.org/tip/505287525c24d5c78b662fd73721ad9900b91fcc
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:36 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:59:01 +0200

irqchip/gic-v3: Add support for Message Based Interrupts as an MSI controller

GICv3 offers the possibility to signal SPIs using a pair of doorbells
(SETPI, CLRSPI) under the name of Message Based Interrupts (MBI).
They can be used as either traditional (edge) MSIs, or the more exotic
level-triggered flavour.

Let's implement support for platform MSI, which is the original intent
for this feature.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-8-marc.zyngier@arm.com

---
 drivers/irqchip/Makefile           |   2 +-
 drivers/irqchip/irq-gic-v3-mbi.c   | 275 +++++++++++++++++++++++++++++++++++++
 drivers/irqchip/irq-gic-v3.c       |   6 +
 include/linux/irqchip/arm-gic-v3.h |   1 +
 4 files changed, 283 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 5ed465ab1c76..15f268f646bf 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -27,7 +27,7 @@ obj-$(CONFIG_ARM_GIC)			+= irq-gic.o irq-gic-common.o
 obj-$(CONFIG_ARM_GIC_PM)		+= irq-gic-pm.o
 obj-$(CONFIG_ARCH_REALVIEW)		+= irq-gic-realview.o
 obj-$(CONFIG_ARM_GIC_V2M)		+= irq-gic-v2m.o
-obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-common.o
+obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-v3-mbi.o irq-gic-common.o
 obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-platform-msi.o irq-gic-v4.o
 obj-$(CONFIG_ARM_GIC_V3_ITS_PCI)	+= irq-gic-v3-its-pci-msi.o
 obj-$(CONFIG_ARM_GIC_V3_ITS_FSL_MC)	+= irq-gic-v3-its-fsl-mc-msi.o
diff --git a/drivers/irqchip/irq-gic-v3-mbi.c b/drivers/irqchip/irq-gic-v3-mbi.c
new file mode 100644
index 000000000000..2b3b767050aa
--- /dev/null
+++ b/drivers/irqchip/irq-gic-v3-mbi.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 ARM Limited, All Rights Reserved.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#define pr_fmt(fmt) "GICv3: " fmt
+
+#include <linux/dma-iommu.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <linux/irqchip/arm-gic-v3.h>
+
+struct mbi_range {
+	u32			spi_start;
+	u32			nr_spis;
+	unsigned long		*bm;
+};
+
+static struct mutex		mbi_lock;
+static phys_addr_t		mbi_phys_base;
+static struct mbi_range		*mbi_ranges;
+static unsigned int		mbi_range_nr;
+
+static struct irq_chip mbi_irq_chip = {
+	.name			= "MBI",
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+};
+
+static int mbi_irq_gic_domain_alloc(struct irq_domain *domain,
+				       unsigned int virq,
+				       irq_hw_number_t hwirq)
+{
+	struct irq_fwspec fwspec;
+	struct irq_data *d;
+	int err;
+
+	/*
+	 * Using ACPI? There is no MBI support in the spec, you
+	 * shouldn't even be here.
+	 */
+	if (!is_of_node(domain->parent->fwnode))
+		return -EINVAL;
+
+	/*
+	 * Let's default to edge. This is consistent with traditional
+	 * MSIs, and systems requiring level signaling will just
+	 * enforce the trigger on their own.
+	 */
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	fwspec.param[0] = 0;
+	fwspec.param[1] = hwirq - 32;
+	fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+
+	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (err)
+		return err;
+
+	d = irq_domain_get_irq_data(domain->parent, virq);
+	return d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
+}
+
+static void mbi_free_msi(struct mbi_range *mbi, unsigned int hwirq,
+			 int nr_irqs)
+{
+	mutex_lock(&mbi_lock);
+	bitmap_release_region(mbi->bm, hwirq - mbi->spi_start,
+			      get_count_order(nr_irqs));
+	mutex_unlock(&mbi_lock);
+}
+
+static int mbi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				   unsigned int nr_irqs, void *args)
+{
+	struct mbi_range *mbi = NULL;
+	int hwirq, offset, i, err = 0;
+
+	mutex_lock(&mbi_lock);
+	for (i = 0; i < mbi_range_nr; i++) {
+		offset = bitmap_find_free_region(mbi_ranges[i].bm,
+						 mbi_ranges[i].nr_spis,
+						 get_count_order(nr_irqs));
+		if (offset >= 0) {
+			mbi = &mbi_ranges[i];
+			break;
+		}
+	}
+	mutex_unlock(&mbi_lock);
+
+	if (!mbi)
+		return -ENOSPC;
+
+	hwirq = mbi->spi_start + offset;
+
+	for (i = 0; i < nr_irqs; i++) {
+		err = mbi_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
+		if (err)
+			goto fail;
+
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+					      &mbi_irq_chip, mbi);
+	}
+
+	return 0;
+
+fail:
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+	mbi_free_msi(mbi, hwirq, nr_irqs);
+	return err;
+}
+
+static void mbi_irq_domain_free(struct irq_domain *domain,
+				unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	struct mbi_range *mbi = irq_data_get_irq_chip_data(d);
+
+	mbi_free_msi(mbi, d->hwirq, nr_irqs);
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops mbi_domain_ops = {
+	.alloc			= mbi_irq_domain_alloc,
+	.free			= mbi_irq_domain_free,
+};
+
+static void mbi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	msg[0].address_hi = upper_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
+	msg[0].address_lo = lower_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
+	msg[0].data = data->parent_data->hwirq;
+
+	iommu_dma_map_msi_msg(data->irq, msg);
+}
+
+static void mbi_compose_mbi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	mbi_compose_msi_msg(data, msg);
+
+	msg[1].address_hi = upper_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
+	msg[1].address_lo = lower_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
+	msg[1].data = data->parent_data->hwirq;
+
+	iommu_dma_map_msi_msg(data->irq, &msg[1]);
+}
+
+/* Platform-MSI specific irqchip */
+static struct irq_chip mbi_pmsi_irq_chip = {
+	.name			= "pMSI",
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_compose_msi_msg	= mbi_compose_mbi_msg,
+	.flags			= IRQCHIP_SUPPORTS_LEVEL_MSI,
+};
+
+static struct msi_domain_ops mbi_pmsi_ops = {
+};
+
+static struct msi_domain_info mbi_pmsi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_LEVEL_CAPABLE),
+	.ops	= &mbi_pmsi_ops,
+	.chip	= &mbi_pmsi_irq_chip,
+};
+
+static int mbi_allocate_domains(struct irq_domain *parent)
+{
+	struct irq_domain *nexus_domain, *plat_domain;
+
+	nexus_domain = irq_domain_create_tree(parent->fwnode,
+					      &mbi_domain_ops, NULL);
+	if (!nexus_domain)
+		return -ENOMEM;
+
+	irq_domain_update_bus_token(nexus_domain, DOMAIN_BUS_NEXUS);
+	nexus_domain->parent = parent;
+
+	plat_domain = platform_msi_create_irq_domain(parent->fwnode,
+						     &mbi_pmsi_domain_info,
+						     nexus_domain);
+
+	if (!plat_domain) {
+		irq_domain_remove(plat_domain);
+		irq_domain_remove(nexus_domain);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int __init mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent)
+{
+	struct device_node *np;
+	const __be32 *reg;
+	int ret, n;
+
+	np = to_of_node(fwnode);
+
+	if (!of_property_read_bool(np, "msi-controller"))
+		return 0;
+
+	n = of_property_count_elems_of_size(np, "mbi-ranges", sizeof(u32));
+	if (n <= 0 || n % 2)
+		return -EINVAL;
+
+	mbi_range_nr = n / 2;
+	mbi_ranges = kcalloc(mbi_range_nr, sizeof(*mbi_ranges), GFP_KERNEL);
+	if (!mbi_ranges)
+		return -ENOMEM;
+
+	for (n = 0; n < mbi_range_nr; n++) {
+		ret = of_property_read_u32_index(np, "mbi-ranges", n * 2,
+						 &mbi_ranges[n].spi_start);
+		if (ret)
+			goto err_free_mbi;
+		ret = of_property_read_u32_index(np, "mbi-ranges", n * 2 + 1,
+						 &mbi_ranges[n].nr_spis);
+		if (ret)
+			goto err_free_mbi;
+
+		mbi_ranges[n].bm = kcalloc(BITS_TO_LONGS(mbi_ranges[n].nr_spis),
+					   sizeof(long), GFP_KERNEL);
+		if (!mbi_ranges[n].bm) {
+			ret = -ENOMEM;
+			goto err_free_mbi;
+		}
+		pr_info("MBI range [%d:%d]\n", mbi_ranges[n].spi_start,
+			mbi_ranges[n].spi_start + mbi_ranges[n].nr_spis - 1);
+	}
+
+	reg = of_get_property(np, "mbi-alias", NULL);
+	if (reg) {
+		mbi_phys_base = of_translate_address(np, reg);
+		if (mbi_phys_base == OF_BAD_ADDR) {
+			ret = -ENXIO;
+			goto err_free_mbi;
+		}
+	} else {
+		struct resource res;
+
+		if (of_address_to_resource(np, 0, &res)) {
+			ret = -ENXIO;
+			goto err_free_mbi;
+		}
+
+		mbi_phys_base = res.start;
+	}
+
+	pr_info("Using MBI frame %pa\n", &mbi_phys_base);
+
+	ret = mbi_allocate_domains(parent);
+	if (ret)
+		goto err_free_mbi;
+
+	return 0;
+
+err_free_mbi:
+	if (mbi_ranges) {
+		for (n = 0; n < mbi_range_nr; n++)
+			kfree(mbi_ranges[n].bm);
+		kfree(mbi_ranges);
+	}
+
+	return ret;
+}
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 94164d7b87a6..5a67ec084588 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1113,6 +1113,12 @@ static int __init gic_init_bases(void __iomem *dist_base,
 	pr_info("Distributor has %sRange Selector support\n",
 		gic_data.has_rss ? "" : "no ");
 
+	if (typer & GICD_TYPER_MBIS) {
+		err = mbi_init(handle, gic_data.domain);
+		if (err)
+			pr_err("Failed to initialize MBIs\n");
+	}
+
 	set_handle_irq(gic_handle_irq);
 
 	gic_update_vlpi_properties();
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index f5af3b594e6e..cbb872c1b607 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -587,6 +587,7 @@ struct fwnode_handle;
 int its_cpu_init(void);
 int its_init(struct fwnode_handle *handle, struct rdists *rdists,
 	     struct irq_domain *domain);
+int mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent);
 
 static inline bool gic_enable_sre(void)
 {

[tip:irq/core] irqchip/gic-v3: Add PCI/MSI support to the GICv3 MBI sub-driver

[tip-bot for Marc Zyngier]

Commit-ID:  38985351492b4ef2f63ffe527ef7cdfa66680f94
Gitweb:     https://git.kernel.org/tip/38985351492b4ef2f63ffe527ef7cdfa66680f94
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:37 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:59:01 +0200

irqchip/gic-v3: Add PCI/MSI support to the GICv3 MBI sub-driver

You would hope that if you have a GICv3 in your system, you'd use the ITS,
as it provides a large interrupt ID space and device isolation. Sadly,
some SoC integrations are less than perfect, and the ITS is not usesable on
those.

The only solution for these systems is to use the MBI interface, and
rely on a very small number of possible vectors.

This patch thus adds minimal support for PCI/MSI on top of the GICv3
MBI driver. Please don't use it if you can avoid it.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-9-marc.zyngier@arm.com

---
 drivers/irqchip/irq-gic-v3-mbi.c | 62 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 59 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-mbi.c b/drivers/irqchip/irq-gic-v3-mbi.c
index 2b3b767050aa..ad70e7c416e3 100644
--- a/drivers/irqchip/irq-gic-v3-mbi.c
+++ b/drivers/irqchip/irq-gic-v3-mbi.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/msi.h>
 #include <linux/of_address.h>
+#include <linux/of_pci.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
@@ -144,6 +145,55 @@ static void mbi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 	iommu_dma_map_msi_msg(data->irq, msg);
 }
 
+#ifdef CONFIG_PCI_MSI
+/* PCI-specific irqchip */
+static void mbi_mask_msi_irq(struct irq_data *d)
+{
+	pci_msi_mask_irq(d);
+	irq_chip_mask_parent(d);
+}
+
+static void mbi_unmask_msi_irq(struct irq_data *d)
+{
+	pci_msi_unmask_irq(d);
+	irq_chip_unmask_parent(d);
+}
+
+static struct irq_chip mbi_msi_irq_chip = {
+	.name			= "MSI",
+	.irq_mask		= mbi_mask_msi_irq,
+	.irq_unmask		= mbi_unmask_msi_irq,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_compose_msi_msg	= mbi_compose_msi_msg,
+	.irq_write_msi_msg	= pci_msi_domain_write_msg,
+};
+
+static struct msi_domain_info mbi_msi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		   MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
+	.chip	= &mbi_msi_irq_chip,
+};
+
+static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
+				   struct irq_domain **pci_domain)
+{
+	*pci_domain = pci_msi_create_irq_domain(nexus_domain->parent->fwnode,
+						&mbi_msi_domain_info,
+						nexus_domain);
+	if (!*pci_domain)
+		return -ENOMEM;
+
+	return 0;
+}
+#else
+static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
+				   struct irq_domain **pci_domain)
+{
+	*pci_domain = NULL;
+	return 0;
+}
+#endif
+
 static void mbi_compose_mbi_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	mbi_compose_msi_msg(data, msg);
@@ -175,7 +225,8 @@ static struct msi_domain_info mbi_pmsi_domain_info = {
 
 static int mbi_allocate_domains(struct irq_domain *parent)
 {
-	struct irq_domain *nexus_domain, *plat_domain;
+	struct irq_domain *nexus_domain, *pci_domain, *plat_domain;
+	int err;
 
 	nexus_domain = irq_domain_create_tree(parent->fwnode,
 					      &mbi_domain_ops, NULL);
@@ -185,12 +236,17 @@ static int mbi_allocate_domains(struct irq_domain *parent)
 	irq_domain_update_bus_token(nexus_domain, DOMAIN_BUS_NEXUS);
 	nexus_domain->parent = parent;
 
+	err = mbi_allocate_pci_domain(nexus_domain, &pci_domain);
+
 	plat_domain = platform_msi_create_irq_domain(parent->fwnode,
 						     &mbi_pmsi_domain_info,
 						     nexus_domain);
 
-	if (!plat_domain) {
-		irq_domain_remove(plat_domain);
+	if (err || !plat_domain) {
+		if (plat_domain)
+			irq_domain_remove(plat_domain);
+		if (pci_domain)
+			irq_domain_remove(pci_domain);
 		irq_domain_remove(nexus_domain);
 		return -ENOMEM;
 	}

[tip:irq/core] dt-bindings/gic-v3: Add documentation for MBI support

[tip-bot for Marc Zyngier]

Commit-ID:  53667c670fe00d63246fb3cfb4480bb1ba247bcc
Gitweb:     https://git.kernel.org/tip/53667c670fe00d63246fb3cfb4480bb1ba247bcc
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Tue, 8 May 2018 13:14:38 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sun, 13 May 2018 15:59:02 +0200

dt-bindings/gic-v3: Add documentation for MBI support

Add the required properties to support the MBI feature on GICv3.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-10-marc.zyngier@arm.com

---
 .../bindings/interrupt-controller/arm,gic-v3.txt        | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
index 0a57f2f4167d..3ea78c4ef887 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
+++ b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
@@ -57,6 +57,20 @@ Optional
   occupied by the redistributors. Required if more than one such
   region is present.
 
+- msi-controller: Boolean property. Identifies the node as an MSI
+  controller. Only present if the Message Based Interrupt
+  functionnality is being exposed by the HW, and the mbi-ranges
+  property present.
+
+- mbi-ranges: A list of pairs <intid span>, where "intid" is the first
+  SPI of a range that can be used an MBI, and "span" the size of that
+  range. Multiple ranges can be provided. Requires "msi-controller" to
+  be set.
+
+- mbi-alias: Address property. Base address of an alias of the GICD
+  region containing only the {SET,CLR}SPI registers to be used if
+  isolation is required, and if supported by the HW.
+
 Sub-nodes:
 
 PPI affinity can be expressed as a single "ppi-partitions" node,
@@ -99,6 +113,9 @@ Examples:
 		      <0x0 0x2c020000 0 0x2000>;	// GICV
 		interrupts = <1 9 4>;
 
+		msi-controller;
+		mbi-ranges = <256 128>;
+
 		gic-its@2c200000 {
 			compatible = "arm,gic-v3-its";
 			msi-controller;