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

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 2bf8d94..b51863f 100644 (file)
--- 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 72c7f62..6e4f771 100644 (file)
--- 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 (file)
--- 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 (file)
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 3c755d5..d770d6a 100644 (file)
--- 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)
@@ -3688,6 +3689,7 @@ 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,
@@ -4993,6 +4995,9 @@ 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;
 }