[tip: irq/core] irqchip/gic-v3-its: Provide MSI parent infrastructure

["tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     e3baf5e45373c788bc7e0d899d1563f2acdb0fa8
Gitweb:        https://git.kernel.org/tip/e3baf5e45373c788bc7e0d899d1563f2acdb0fa8
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Sun, 23 Jun 2024 17:18:36 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 10 Jul 2024 18:19:23 +02:00

irqchip/gic-v3-its: Provide MSI parent infrastructure

To support per device MSI domains the ITS must provide MSI parent domain
functionality.

Provide the basic skeleton for this:

   - msi_parent_ops
   - child domain init callback
   - the MSI parent flag set in irqdomain::flags

This does not make ITS a functional parent domain as there is no bit set in
the bus_select_mask yet, but it provides the base to implement PCI and
platform MSI support gradually on top.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Shivamurthy Shastri <shivamurthy.shastri@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240623142234.903076277@linutronix.de



---
 drivers/irqchip/Kconfig                     |  1 +-
 drivers/irqchip/Makefile                    |  2 +-
 drivers/irqchip/irq-gic-common.h            |  3 ++-
 drivers/irqchip/irq-gic-v3-its-msi-parent.c | 31 ++++++++++++++++++++-
 drivers/irqchip/irq-gic-v3-its.c            |  5 +++-
 5 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 drivers/irqchip/irq-gic-v3-its-msi-parent.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 3e3cbe9..ee78716 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -41,6 +41,7 @@ config ARM_GIC_V3
 config ARM_GIC_V3_ITS
 	bool
 	select GENERIC_MSI_IRQ
+	select IRQ_MSI_LIB
 	default ARM_GIC_V3
 
 config ARM_GIC_V3_ITS_PCI
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index f5e0fa9..def6fea 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -32,7 +32,7 @@ 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-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-platform-msi.o irq-gic-v4.o
+obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-platform-msi.o irq-gic-v4.o irq-gic-v3-its-msi-parent.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
 obj-$(CONFIG_PARTITION_PERCPU)		+= irq-partition-percpu.o
diff --git a/drivers/irqchip/irq-gic-common.h b/drivers/irqchip/irq-gic-common.h
index f407cce..eb4a220 100644
--- a/drivers/irqchip/irq-gic-common.h
+++ b/drivers/irqchip/irq-gic-common.h
@@ -8,6 +8,7 @@
 
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/msi.h>
 #include <linux/irqchip/arm-gic-common.h>
 
 struct gic_quirk {
@@ -29,6 +30,8 @@ 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-v3-its-msi-parent.c
new file mode 100644
index 0000000..cdc0844
--- /dev/null
+++ b/drivers/irqchip/irq-gic-v3-its-msi-parent.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2022 Linutronix GmbH
+// Copyright (C) 2022 Intel
+
+#include "irq-gic-common.h"
+#include "irq-msi-lib.h"
+
+#define ITS_MSI_FLAGS_REQUIRED  (MSI_FLAG_USE_DEF_DOM_OPS |	\
+				 MSI_FLAG_USE_DEF_CHIP_OPS)
+
+#define ITS_MSI_FLAGS_SUPPORTED (MSI_GENERIC_FLAGS_MASK |	\
+				 MSI_FLAG_PCI_MSIX      |	\
+				 MSI_FLAG_MULTI_PCI_MSI |	\
+				 MSI_FLAG_PCI_MSI_MASK_PARENT)
+
+static bool its_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
+				  struct irq_domain *real_parent, struct msi_domain_info *info)
+{
+	if (!msi_lib_init_dev_msi_info(dev, domain, real_parent, info))
+		return false;
+
+	return true;
+}
+
+const struct msi_parent_ops gic_v3_its_msi_parent_ops = {
+	.supported_flags	= ITS_MSI_FLAGS_SUPPORTED,
+	.required_flags		= ITS_MSI_FLAGS_REQUIRED,
+	.bus_select_token	= DOMAIN_BUS_NEXUS,
+	.prefix			= "ITS-",
+	.init_dev_msi_info	= its_init_dev_msi_info,
+};
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index af5297e..047e566 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -38,6 +38,7 @@
 #include <asm/exception.h>
 
 #include "irq-gic-common.h"
+#include "irq-msi-lib.h"
 
 #define ITS_FLAGS_CMDQ_NEEDS_FLUSHING		(1ULL << 0)
 #define ITS_FLAGS_WORKAROUND_CAVIUM_22375	(1ULL << 1)
@@ -3708,6 +3709,7 @@ static void its_irq_domain_free(struct irq_domain *domain, unsigned int virq,
 }
 
 static const struct irq_domain_ops its_domain_ops = {
+	.select			= msi_lib_irq_domain_select,
 	.alloc			= its_irq_domain_alloc,
 	.free			= its_irq_domain_free,
 	.activate		= its_irq_domain_activate,
@@ -5013,6 +5015,9 @@ 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->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT;
+
 	return 0;
 }